Publications

Title / Authors / Details Open Access Download

Stem-cell-derived human microglia transplanted in mouse brain to study human disease.
Mancuso R, Van Den Daele J, Fattorelli N, Wolfs L, Balusu S, Burton O, Liston A, Sierksma A, Fourne Y, Poovathingal S, Arranz-Mendiguren A, Sala Frigerio C, Claes C, Serneels L, Theys T, Perry VH, Verfaillie C, Fiers M, De Strooper B

Although genetics highlights the role of microglia in Alzheimer's disease, one-third of putative Alzheimer's disease risk genes lack adequate mouse orthologs. Here we successfully engraft human microglia derived from embryonic stem cells in the mouse brain. The cells recapitulate transcriptionally human primary microglia ex vivo and show expression of human-specific Alzheimer's disease risk genes. Oligomeric amyloid-β induces a divergent response in human versus mouse microglia. This model can be used to study the role of microglia in neurological diseases.

+ View Abstract

Nature neuroscience, , 1546-1726, , 2019

PMID:31659342

Longitudinal In Vivo Assessment of Host-Microbe Interactions in a Murine Model of Pulmonary Aspergillosis.
Saini S, Poelmans J, Korf H, Dooley JL, Liang S, Manshian BB, Verbeke R, Soenen SJ, Vande Velde G, Lentacker I, Lagrou K, Liston A, Gysemans C, De Smedt SC, Himmelreich U

The fungus Aspergillus fumigatus is ubiquitous in nature and the most common cause of invasive pulmonary aspergillosis (IPA) in patients with a compromised immune system. The development of IPA in patients under immunosuppressive treatment or in patients with primary immunodeficiency demonstrates the importance of the host immune response in controlling aspergillosis. However, study of the host-microbe interaction has been hampered by the lack of tools for their non-invasive assessment. We developed a methodology to study the response of the host's immune system against IPA longitudinally in vivo by using fluorine-19 magnetic resonance imaging (F MRI). We showed the advantage of a perfluorocarbon-based contrast agent for the in vivo labeling of macrophages and dendritic cells, permitting quantification of pulmonary inflammation in different murine IPA models. Our findings reveal the potential of F MRI for the assessment of rapid kinetics of innate immune response against IPA and the permissive niche generated through immunosuppression.

+ View Abstract

iScience, 20, 2589-0042, , 2019

PMID:31581067

Open Access

Safe targeting of T cell acute lymphoblastic leukemia by pathology-specific NOTCH inhibition.
Habets RA, de Bock CE, Serneels L, Lodewijckx I, Verbeke D, Nittner D, Narlawar R, Demeyer S, Dooley J, Liston A, Taghon T, Cools J, de Strooper B

Given the high frequency of activating mutations in T cell acute lymphoblastic leukemia (T-ALL), inhibition of the γ-secretase complex remains an attractive target to prevent ligand-independent release of the cytoplasmic tail and oncogenic NOTCH1 signaling. However, four different γ-secretase complexes exist, and available inhibitors block all complexes equally. As a result, these cause severe "on-target" gastrointestinal tract, skin, and thymus toxicity, limiting their therapeutic application. Here, we demonstrate that genetic deletion or pharmacologic inhibition of the presenilin-1 (PSEN1) subclass of γ-secretase complexes is highly effective in decreasing leukemia while avoiding dose-limiting toxicities. Clinically, T-ALL samples were found to selectively express only PSEN1-containing γ-secretase complexes. The conditional knockout of in developing T cells attenuated the development of a mutant NOTCH1-driven leukemia in mice in vivo but did not abrogate normal T cell development. Treatment of T-ALL cell lines with the selective PSEN1 inhibitor MRK-560 effectively decreased mutant NOTCH1 processing and led to cell cycle arrest. These observations were extended to T-ALL patient-derived xenografts in vivo, demonstrating that MRK-560 treatment decreases leukemia burden and increased overall survival without any associated gut toxicity. Therefore, PSEN1-selective compounds provide a potential therapeutic strategy for safe and effective targeting of T-ALL and possibly also for other diseases in which NOTCH signaling plays a role.

+ View Abstract

Science translational medicine, 11, 1946-6242, , 2019

PMID:31142678

Inborn errors of immunity: single mutations unravel mechanisms of immune disease.
Liston A, Humblet-Baron S

Immunology and cell biology, , 1440-1711, , 2019

PMID:30942931

The Aire family expands.
Liston A, Dooley J

T cell tolerance depends upon Aire-expressing cells to purge the T cell repertoire of autoreactive clones. Once thought to be the exclusive domain of thymic epithelial cells, a new study by Yamano et al. (https://doi.org/10.1084/jem.20181430) in this issue of identifies ILC3-like cells in the lymph nodes with similar properties.

+ View Abstract

The Journal of experimental medicine, , 1540-9538, , 2019

PMID:30923044

Machine learning identifies an immunological pattern associated with multiple juvenile idiopathic arthritis subtypes.
Van Nieuwenhove E, Lagou V, Van Eyck L, Dooley J, Bodenhofer U, Roca C, Vandebergh M, Goris A, Humblet-Baron S, Wouters C, Liston A

Juvenile idiopathic arthritis (JIA) is the most common class of childhood rheumatic diseases, with distinct disease subsets that may have diverging pathophysiological origins. Both adaptive and innate immune processes have been proposed as primary drivers, which may account for the observed clinical heterogeneity, but few high-depth studies have been performed.

+ View Abstract

Annals of the rheumatic diseases, , 1468-2060, , 2019

PMID:30862608

Prospective study evaluating immune-mediated mechanisms and predisposing factors underlying persistent postinfectious abdominal complaints.
Florens MV, Van Wanrooy S, Dooley J, Aguilera-Lizarraga J, Vanbrabant W, Wouters MM, Van Oudenhove L, Peetermans WE, Liston A, Boeckxstaens GE

The role of persistent immune activation in postinfectious irritable bowel syndrome (PI-IBS) remains controversial. Here, we prospectively studied healthy subjects traveling to destinations with a high-risk to develop infectious gastroenteritis (IGE) in order to identify immune-mediated mechanisms and risk factors of PI-IBS.

+ View Abstract

Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society, 31, 1365-2982, , 2019

PMID:30657233

IFN-γ and CD25 drive distinct pathologic features during hemophagocytic lymphohistiocytosis.
Humblet-Baron S, Franckaert D, Dooley J, Ailal F, Bousfiha A, Deswarte C, Oleaga-Quintas C, Casanova JL, Bustamante J, Liston A

Inflammatory activation of CD8 T cells can, when left unchecked, drive severe immunopathology. Hyperstimulation of CD8 T cells through a broad set of triggering signals can precipitate hemophagocytic lymphohistiocytosis (HLH), a life-threatening systemic inflammatory disorder.

+ View Abstract

The Journal of allergy and clinical immunology, , 1097-6825, , 2018

PMID:30578871

NFIL3 mutations alter immune homeostasis and sensitise for arthritis pathology.
Schlenner S, Pasciuto E, Lagou V, Burton O, Prezzemolo T, Junius S, Roca CP, Seillet C, Louis C, Dooley J, Luong K, Van Nieuwenhove E, Wicks IP, Belz G, Humblet-Baron S, Wouters C, Liston A

is a key immunological transcription factor, with knockout mice studies identifying functional roles in multiple immune cell types. Despite the importance of NFIL3, little is known about its function in humans.

+ View Abstract

Annals of the rheumatic diseases, 78, 1468-2060, , 2019

PMID:30552177

Open Access

A robust pipeline with high replication rate for detection of somatic variants in the adaptive immune system as a source of common genetic variation in autoimmune disease.
Van Horebeek L, Hilven K, Mallants K, Van Nieuwenhuijze A, Kelkka T, Savola P, Mustjoki S, Schlenner SM, Liston A, Dubois B, Goris A

The role of somatic variants in diseases beyond cancer is increasingly being recognized, with potential roles in autoinflammatory and autoimmune diseases. However, as mutation rates and allele fractions are lower, studies in these diseases are substantially less tolerant of false positives and bio-informatics algorithms require high replication rates. We developed a pipeline combining two variant callers, MuTect2 and VarScan2, with technical filtering and prioritization. Our pipeline detects somatic variants with allele fractions as low as 0.5% and achieves a replication rate >55%. Validation in an independent dataset demonstrates excellent performance (sensitivity >57%, specificity >98%, replication rate >80%). We applied this pipeline to the autoimmune disease multiple sclerosis (MS) as a proof-of-principle. We demonstrate that 60% of MS patients carry 2-10 exonic somatic variants in their peripheral blood T and B cells, with the vast majority (80%) occurring in T cells and variants persisting over time. Synonymous variants significantly co-occur with nonsynonymous variants. Systematic characterization indicates somatic variants are enriched for being novel or very rare in public databases of germline variants and trend towards being more damaging and conserved, as reflected by higher CADD and GERP scores. Our pipeline and proof-of-principle now warrant further investigation of common somatic genetic variation on top of inherited genetic variation in the context of autoimmune disease, where it may offer subtle survival advantages to immune cells and contribute to the capacity of these cells to participate in the autoimmune reaction.

+ View Abstract

Human molecular genetics, , 1460-2083, , 2018

PMID:30541027

Murine myeloproliferative disorder as a consequence of impaired collaboration between dendritic cells and CD4 T cells.
Humblet-Baron S, Barber JS, Roca CP, Lenaerts A, Koni PA, Liston A

Dendritic cells (DCs) are a key cell type in the initiation of the adaptive immune response. Recently, an additional role for DCs in suppressing myeloproliferation was discovered. Myeloproliferative disorder (MPD) was observed in murine studies with constitutive depletion of DCs, as well as in patients with congenital deficiency in DCs caused by mutations in or The mechanistic link between DC deficiency and MPD was not predicted through the known biology and has remained an enigma. Prevailing models suggest numerical DC deficiency leads to MPD through compensatory myeloid differentiation. Here, we formally tested whether MPD can also arise through a loss of DC function without numerical deficiency. Using mice whose DCs are deficient in antigen presentation, we find spontaneous MPD that is characterized by splenomegaly, neutrophilia, and extramedullary hematopoiesis, despite normal numbers of DCs. Disease development was dependent on loss of the MHC class II (MHCII) antigen-presenting complex on DCs and was eliminated in mice deficient in total lymphocytes. Mice lacking MHCII and CD4 T cells did not develop disease. Thus, MPD was paradoxically contingent on the presence of CD4 T cells and on a failure of DCs to activate CD4 T cells, trapping the cells in a naive Flt3 ligand-expressing state. These results identify a novel requirement for intercellular collaboration between DCs and CD4 T cells to regulate myeloid differentiation. Our findings support a new conceptual framework of DC biology in preventing MPD in mice and humans.

+ View Abstract

Blood, 133, 1528-0020, , 2019

PMID:30333120

Open Access

Genetic Architecture of Adaptive Immune System Identifies Key Immune Regulators.
Lagou V, Garcia-Perez JE, Smets I, Van Horebeek L, Vandebergh M, Chen L, Mallants K, Prezzemolo T, Hilven K, Humblet-Baron S, Moisse M, Van Damme P, Boeckxstaens G, Bowness P, Dubois B, Dooley J, Liston A, Goris A

The immune system is highly diverse, but characterization of its genetic architecture has lagged behind the vast progress made by genome-wide association studies (GWASs) of emergent diseases. Our GWAS for 54 functionally relevant phenotypes of the adaptive immune system in 489 healthy individuals identifies eight genome-wide significant associations explaining 6%-20% of variance. Coding and splicing variants in PTPRC and COMMD10 are involved in memory T cell differentiation. Genetic variation controlling disease-relevant T helper cell subsets includes RICTOR and STON2 associated with Th2 and Th17, respectively, and the interferon-lambda locus controlling regulatory T cell proliferation. Early and memory B cell differentiation stages are associated with variation in LARP1B and SP4. Finally, the latrophilin family member ADGRL2 correlates with baseline pro-inflammatory interleukin-6 levels. Suggestive associations reveal mechanisms of autoimmune disease associations, in particular related to pro-inflammatory cytokine production. Pinpointing these key human immune regulators offers attractive therapeutic perspectives.

+ View Abstract

Cell reports, 25, 2211-1247, , 2018

PMID:30332657

Open Access

Mice Deficient in Nucleoporin Nup210 Develop Peripheral T Cell Alterations.
van Nieuwenhuijze A, Burton O, Lemaitre P, Denton AE, Cascalho A, Goodchild RE, Malengier-Devlies B, Cauwe B, Linterman MA, Humblet-Baron S, Liston A

The nucleopore is an essential structure of the eukaryotic cell, regulating passage between the nucleus and cytoplasm. While individual functions of core nucleopore proteins have been identified, the role of other components, such as Nup210, are poorly defined. Here, through the use of an unbiased ENU mutagenesis screen for mutations effecting the peripheral T cell compartment, we identified a Nup210 mutation in a mouse strain with altered CD4/CD8 T cell ratios. Through the generation of Nup210 knockout mice we identified Nup210 as having a T cell-intrinsic function in the peripheral homeostasis of T cells. Remarkably, despite the deep evolutionary conservation of this key nucleopore complex member, no other major phenotypes developed, with viable and healthy knockout mice. These results identify Nup210 as an important nucleopore complex component for peripheral T cells, and raise further questions of why this nucleopore component shows deep evolutionary conservation despite seemingly redundant functions in most cell types.

+ View Abstract

Frontiers in immunology, 9, 1664-3224, , 2018

PMID:30323813

Open Access

The Long Non-coding RNA Anticipates Foxp3 Expression in Regulatory T Cells.
Brajic A, Franckaert D, Burton O, Bornschein S, Calvanese AL, Demeyer S, Cools J, Dooley J, Schlenner S, Liston A

Mammalian genomes encode a plethora of long non-coding RNA (lncRNA). These transcripts are thought to regulate gene expression, influencing biological processes from development to pathology. Results from the few lncRNA that have been studied in the context of the immune system have highlighted potentially critical functions as network regulators. Here we explored the nature of the lncRNA transcriptome in regulatory T cells (Tregs), a subset of CD4 T cells required to establish and maintain immunological self-tolerance. The identified Treg lncRNA transcriptome showed distinct differences from that of non-regulatory CD4 T cells, with evidence of direct shaping of the lncRNA transcriptome by Foxp3, the master transcription factor driving the distinct mRNA profile of Tregs. Treg lncRNA changes were disproportionally reversed in the absence of Foxp3, with an enrichment for colocalisation with Foxp3 DNA binding sites, indicating a direct coordination of transcription by Foxp3 independent of the mRNA coordination function. We further identified a novel lncRNA , as a member of the core Treg lncRNA transcriptome. expression anticipates Foxp3 expression during Treg conversion, and -deficient mice show a mild delay in and peripheral Treg induction. These results implicate as part of the upstream cascade leading to Treg conversion, and may provide clues as to the nature of this process.

+ View Abstract

Frontiers in immunology, 9, 1664-3224, , 2018

PMID:30319599

Open Access

Insufficient IL-10 Production as a Mechanism Underlying the Pathogenesis of Systemic Juvenile Idiopathic Arthritis.
Imbrechts M, Avau A, Vandenhaute J, Malengier-Devlies B, Put K, Mitera T, Berghmans N, Burton O, Junius S, Liston A, de Somer L, Wouters C, Matthys P

Systemic juvenile idiopathic arthritis (sJIA) is a childhood-onset immune disorder of unknown cause. One of the concepts is that the disease results from an inappropriate control of immune responses to an initially harmless trigger. In the current study, we investigated whether sJIA may be caused by defects in IL-10, a key cytokine in controlling inflammation. We used a translational approach, with an sJIA-like mouse model and sJIA patient samples. The sJIA mouse model relies on injection of CFA in IFN-γ-deficient BALB/c mice; corresponding wild type (WT) mice only develop a subtle and transient inflammatory reaction. Diseased IFN-γ-deficient mice showed a defective IL-10 production in CD4 regulatory T cells, CD19 B cells, and CD3CD122CD49b NK cells, with B cells as the major source of IL-10. In addition, neutralization of IL-10 in WT mice resulted in a chronic immune inflammatory disorder clinically and hematologically reminiscent of sJIA. In sJIA patients, IL-10 plasma levels were strikingly low as compared with proinflammatory mediators. Furthermore, CD19 B cells from sJIA patients showed a decreased IL-10 production, both ex vivo and after in vitro stimulation. In conclusion, IL-10 neutralization in CFA-challenged WT mice converts a transient inflammatory reaction into a chronic disease and represents an alternative model for sJIA in IFN-γ-competent mice. Cell-specific IL-10 defects were observed in sJIA mice and patients, together with an insufficient IL-10 production to counterbalance their proinflammatory cytokines. Our data indicate that a defective IL-10 production contributes to the pathogenesis of sJIA.

+ View Abstract

Journal of immunology (Baltimore, Md. : 1950), 201, 1550-6606, , 2018

PMID:30266771

ADA2 Deficiency Mimicking Idiopathic Multicentric Castleman Disease.
Van Nieuwenhove E, Humblet-Baron S, Van Eyck L, De Somer L, Dooley J, Tousseyn T, Hershfield M, Liston A, Wouters C

Multicentric Castleman disease (MCD) is a rare entity that, unlike unicentric Castleman disease, involves generalized polyclonal lymphoproliferation, systemic inflammation, and multiple-organ system failure resulting from proinflammatory hypercytokinemia, including, in particular, interleukin-6. A subset of MCD is caused by human herpesvirus-8 (HHV-8), although the etiology for HHV-8-negative, idiopathic MCD (iMCD) cases is unknown at present. Recently, a consensus was reached on the diagnostic criteria for iMCD to aid in diagnosis, recognize mimics, and initiate prompt treatment. Pediatric iMCD remains particularly rare, and differentiation from MCD mimics in children presenting with systemic inflammation and lymphoproliferation is a challenge. We report on a young boy who presented with a HHV-8-negative, iMCD-like phenotype and was found to suffer from the monogenic disorder deficiency of adenosine deaminase 2 (DADA2), which is caused by loss-of-function mutations in DADA2 prototypic features include early-onset ischemic and hemorrhagic strokes, livedoid rash, systemic inflammation, and polyarteritis nodosa vasculopathy, but marked clinical heterogeneity has been observed. Our patient's presentation remains unique, with predominant systemic inflammation, lymphoproliferation, and polyclonal hypergammaglobulinemia but without apparent immunodeficiency. On the basis of the iMCD-like phenotype with elevated interleukin-6 expression, treatment with tocilizumab was initiated, resulting in immediate normalization of clinical and biochemical parameters. In conclusion, iMCD and DADA2 should be considered in the differential diagnosis of children presenting with systemic inflammation and lymphoproliferation. We describe the first case of DADA2 that mimics the clinicopathologic features of iMCD, and our report extends the clinical spectrum of DADA2 to include predominant immune activation and lymphoproliferation.

+ View Abstract

Pediatrics, 142, 1098-4275, , 2018

PMID:30139808

An avian foundation for dominant tolerance.
Liston A

Nature reviews. Immunology, 18, 1474-1741, , 2018

PMID:30097638

Phenotype molding of stromal cells in the lung tumor microenvironment.
Lambrechts D, Wauters E, Boeckx B, Aibar S, Nittner D, Burton O, Bassez A, Decaluwé H, Pircher A, Van den Eynde K, Weynand B, Verbeken E, De Leyn P, Liston A, Vansteenkiste J, Carmeliet P, Aerts S, Thienpont B

Cancer cells are embedded in the tumor microenvironment (TME), a complex ecosystem of stromal cells. Here, we present a 52,698-cell catalog of the TME transcriptome in human lung tumors at single-cell resolution, validated in independent samples where 40,250 additional cells were sequenced. By comparing with matching non-malignant lung samples, we reveal a highly complex TME that profoundly molds stromal cells. We identify 52 stromal cell subtypes, including novel subpopulations in cell types hitherto considered to be homogeneous, as well as transcription factors underlying their heterogeneity. For instance, we discover fibroblasts expressing different collagen sets, endothelial cells downregulating immune cell homing and genes coregulated with established immune checkpoint transcripts and correlating with T-cell activity. By assessing marker genes for these cell subtypes in bulk RNA-sequencing data from 1,572 patients, we illustrate how these correlate with survival, while immunohistochemistry for selected markers validates them as separate cellular entities in an independent series of lung tumors. Hence, in providing a comprehensive catalog of stromal cells types and by characterizing their phenotype and co-optive behavior, this resource provides deeper insights into lung cancer biology that will be helpful in advancing lung cancer diagnosis and therapy.

+ View Abstract

Nature medicine, 24, 1546-170X, , 2018

PMID:29988129

A kindred with mutant IKAROS and autoimmunity.
Van Nieuwenhove E, Garcia-Perez JE, Helsen C, Rodriguez PD, van Schouwenburg PA, Dooley J, Schlenner S, van der Burg M, Verhoeyen E, Gijsbers R, Frietze S, Schjerven H, Meyts I, Claessens F, Humblet-Baron S, Wouters C, Liston A

The Journal of allergy and clinical immunology, 142, 1097-6825, , 2018

PMID:29705243

A Framework for Understanding the Evasion of Host Immunity by Biofilms.
Garcia-Perez JE, Mathé L, Humblet-Baron S, Braem A, Lagrou K, Van Dijck P, Liston A

biofilms are a major cause of nosocomial morbidity and mortality. The mechanism by which biofilms evade the immune system remains unknown. In this perspective, we develop a theoretical framework of the three, not mutually exclusive, models, which could explain biofilm evasion of host immunity. First, biofilms may exhibit properties of immunological silence, preventing immune activation. Second, biofilms may produce immune-deviating factors, converting effective immunity into ineffective immunity. Third, biofilms may resist host immunity, which would otherwise be effective. Using a murine subcutaneous biofilm model, we found that mice infected with biofilms developed sterilizing immunity effective when challenged with yeast form . Despite the induction of effective anti- immunity, no spontaneous clearance of the biofilm was observed. These results support the immune resistance model of biofilm immune evasion and demonstrate an asymmetric relationship between the host and biofilms, with biofilms eliciting effective immune responses yet being resistant to immunological clearance.

+ View Abstract

Frontiers in immunology, 9, 1664-3224, , 2018

PMID:29616035

Open Access

The origins of diversity in human immunity.
Liston A, Goris A

Nature immunology, 19, 1529-2916, , 2018

PMID:29476185

Abnormal differentiation of B cells and megakaryocytes in patients with Roifman syndrome.
Heremans J, Garcia-Perez JE, Turro E, Schlenner SM, Casteels I, Collin R, de Zegher F, Greene D, Humblet-Baron S, Lesage S, Matthys P, Penkett CJ, Put K, Stirrups K, , Thys C, Van Geet C, Van Nieuwenhove E, Wouters C, Meyts I, Freson K, Liston A

Roifman syndrome is a rare inherited disorder characterized by spondyloepiphyseal dysplasia, growth retardation, cognitive delay, hypogammaglobulinemia, and, in some patients, thrombocytopenia. Compound heterozygous variants in the small nuclear RNA gene RNU4ATAC, which is necessary for U12-type intron splicing, were identified recently as driving Roifman syndrome.

+ View Abstract

The Journal of allergy and clinical immunology, 142, 1097-6825, , 2018

PMID:29391254

Multiple sclerosis risk variants alter expression of co-stimulatory genes in B cells.
Smets I, Fiddes B, Garcia-Perez JE, He D, Mallants K, Liao W, Dooley J, Wang G, Humblet-Baron S, Dubois B, Compston A, Jones J, Coles A, Liston A, Ban M, Goris A, Sawcer S

The increasing evidence supporting a role for B cells in the pathogenesis of multiple sclerosis prompted us to investigate the influence of known susceptibility variants on the surface expression of co-stimulatory molecules in these cells. Using flow cytometry we measured surface expression of CD40 and CD86 in B cells from 68 patients and 162 healthy controls that were genotyped for the multiple sclerosis associated single nucleotide polymorphisms (SNPs) rs4810485, which maps within the CD40 gene, and rs9282641, which maps within the CD86 gene. We found that carrying the risk allele rs4810485*T lowered the cell-surface expression of CD40 in all tested B cell subtypes (in total B cells P ≤ 5.10 × 10-5 in patients and ≤4.09 × 10-6 in controls), while carrying the risk allele rs9282641*G increased the expression of CD86, with this effect primarily seen in the naïve B cell subset (P = 0.048 in patients and 5.38 × 10-5 in controls). In concordance with these results, analysis of RNA expression demonstrated that the risk allele rs4810485*T resulted in lower total CD40 [removed]P = 0.057) but with an increased proportion of alternative splice-forms leading to decoy receptors (P = 4.00 × 10-7). Finally, we also observed that the risk allele rs4810485*T was associated with decreased levels of interleukin-10 (P = 0.020), which is considered to have an immunoregulatory function downstream of CD40. Given the importance of these co-stimulatory molecules in determining the immune reaction that appears in response to antigen our data suggest that B cells might have an important antigen presentation and immunoregulatory role in the pathogenesis of multiple sclerosis.

+ View Abstract

Brain : a journal of neurology, 141, 1460-2156, , 2018

PMID:29361022

Open Access

NOD mice, susceptible to pancreatic autoimmunity, demonstrate delayed growth of pancreatic cancer.
Dooley J, Pasciuto E, Lagou V, Lampi Y, Dresselaers T, Himmelreich U, Liston A

Pancreatic cancer is a high mortality form of cancer, with a median survival only six months. There are multiple associated risk factors associated, most importantly type 2 diabetes, obesity, pancreatitis and smoking. The relative rarity of the disease, however, has made it difficult to dissect causative risk factors, especially with related risk factors. A major unanswered question with important therapeutic implications is the effect of immunological responses on pancreatic cancer formation, with data from other cancers suggesting the potential for local immunological responses to either increase cancer development or increase cancer elimination. Due to the rarity and late diagnosis of pancreatic cancer direct epidemiological evidence is lacking, thus necessitating a reliance on animal models. Here we investigated the relationship between pancreatic autoimmunity and cancer by backcrossing the well characterised Ela1-Tag transgenic model of pancreatic cancer onto the pancreatic autoimmune susceptible NOD mouse strain. Through longitudinal magnetic resonance imaging we found that the NOD genetic background delayed the onset of pancreatic tumours and substantially slowed the growth rate of tumours after development. These results suggest that elevated autoimmune surveillance of the pancreas limits tumour formation and growth, identifying pancreatic cancer as a promising target for immune checkpoint blockade therapies that unleash latent autoimmunity.

+ View Abstract

Oncotarget, 8, 1949-2553, , 2017

PMID:29113292

Open Access

CCR7 Modulates the Generation of Thymic Regulatory T Cells by Altering the Composition of the Thymic Dendritic Cell Compartment.
Hu Z, Li Y, Van Nieuwenhuijze A, Selden HJ, Jarrett AM, Sorace AG, Yankeelov TE, Liston A, Ehrlich LIR

Upon recognition of auto-antigens, thymocytes are negatively selected or diverted to a regulatory T cell (Treg) fate. CCR7 is required for negative selection of auto-reactive thymocytes in the thymic medulla. Here, we describe an unanticipated contribution of CCR7 to intrathymic Treg generation. Ccr7 mice have increased Treg cellularity because of a hematopoietic but non-T cell autonomous CCR7 function. CCR7 expression by thymic dendritic cells (DCs) promotes survival of mature Sirpα DCs. Thus, CCR7 deficiency results in apoptosis of Sirpα DCs, which is counterbalanced by expansion of immature Sirpα DCs that efficiently induce Treg generation. CCR7 deficiency results in enhanced intrathymic generation of Tregs at the neonatal stage and in lymphopenic adults, when Treg differentiation is critical for establishing self-tolerance. Together, these results reveal a complex function for CCR7 in thymic tolerance induction, where CCR7 not only promotes negative selection but also governs intrathymic Treg generation via non-thymocyte intrinsic mechanisms.

+ View Abstract

Cell reports, 21, 2211-1247, , 2017

PMID:28978470

Open Access

Murine Pancreatic Acinar Cell Carcinoma Growth Kinetics Are Independent of Dietary Vitamin D Deficiency or Supplementation.
Dooley J, Lagou V, Heirman N, Dresselaers T, Himmelreich U, Liston A

Vitamin D has been proposed as a therapeutic strategy in pancreatic cancer, yet evidence for an effect of dietary vitamin D on pancreatic cancer is ambiguous, with conflicting data from human epidemiological and intervention studies. Here, we tested the role of dietary vitamin D in the context of the well-characterized Ela1-TAg transgenic mouse model of pancreatic acinar cell carcinoma. Through longitudinal magnetic resonance imaging of mice under conditions of either dietary vitamin D deficiency (<5 IU/kg vitamin D) or excess (76,500 IU/kg vitamin D), compared to control diet (1,500 IU/kg vitamin D), we measured the effect of variation of dietary vitamin D on tumor kinetics. No measurable impact of dietary vitamin D was found on pancreatic acinar cell carcinoma development, growth or mortality, casting further doubt on the already equivocal data supporting potential therapeutic use in humans. The lack of any detectable effect of vitamin D, within the physiological range of dietary deficiency or supplementation, in this model further erodes confidence in vitamin D as an effective antitumor therapeutic in pancreatic acinar cell carcinoma.

+ View Abstract

Frontiers in oncology, 7, 2234-943X, , 2017

PMID:28702373

Open Access

No Functional Role for microRNA-342 in a Mouse Model of Pancreatic Acinar Carcinoma.
Dooley J, Lagou V, Pasciuto E, Linterman MA, Prosser HM, Himmelreich U, Liston A

The intronic microRNA (miR)-342 has been proposed as a potent tumor-suppressor gene. miR-342 is found to be downregulated or epigenetically silenced in multiple different tumor sites, and this loss of expression permits the upregulation of several key oncogenic pathways. In several different cell lines, lower miR-342 expression results in enhanced proliferation and metastasis potential, both in vitro and in xenogenic transplant conditions. Here, we sought to determine the function of miR-342 in an in vivo spontaneous cancer model, using the Ela1-TAg transgenic model of pancreatic acinar carcinoma. Through longitudinal magnetic resonance imaging monitoring of Ela1-TAg transgenic mice, either wild-type or knockout for miR-342, we found no role for miR-342 in the development, growth rate, or pathogenicity of pancreatic acinar carcinoma. These results indicate the importance of assessing miR function in the complex physiology of in vivo model systems and indicate that further functional testing of miR-342 is required before concluding it is a bona fide tumor-suppressor-miR.

+ View Abstract

Frontiers in oncology, 7, , , 2017

PMID:28573106

Open Access

miR-29a-deficiency does not modify the course of murine pancreatic acinar carcinoma.
Dooley J, Lagou V, Garcia-Perez JE, Himmelreich U, Liston A

The development of cancers involves the complex dysregulation of multiple cellular processes. With key functions in simultaneous regulation of multiple pathways, microRNA (miR) are thought to have important roles in the oncogenic formation process. miR-29a is among the most abundantly expressed miR in the pancreas. Together with altered expression in pancreatic cancer cell lines and biopsies, and known oncogenic functions in leukemia, this expression data has identified miR-29a as a key candidate for miR involvement in pancreatic cancer biology. Here we used miR-29a-deficient mice and the TAg model of pancreatic acinar carcinoma to functionally test the role of miR-29a in vivo. We found no impact of miR-29a loss on the development or growth of pancreatic tumours, nor on the survival of tumour-bearing mice. These results suggest that, despite differential expression, miR-29a is oncogenically neutral in the pancreatic acinar carcinoma context. If these results are extended to other models of pancreatic cancer, they would reduce the attractiveness of miR-29a as a potential therapeutic target in pancreatic cancer.

+ View Abstract

Oncotarget, 8, 1949-2553, , 2017

PMID:28460473

Open Access

Non-invasive assessment of murine PD-L1 levels in syngeneic tumor models by nuclear imaging with nanobody tracers.
Broos K, Keyaerts M, Lecocq Q, Renmans D, Nguyen T, Escors D, Liston A, Raes G, Breckpot K, Devoogdt N

Blockade of the inhibitory PD-1/PD-L1 immune checkpoint axis is a promising cancer treatment. Nonetheless, a significant number of patients and malignancies do not respond to this therapy. To develop a screen for response to PD-1/PD-L1 inhibition, it is critical to develop a non-invasive tool to accurately assess dynamic immune checkpoint expression. Here we evaluated non-invasive SPECT/CT imaging of PD-L1 expression, in murine tumor models with varying PD-L1 expression, using high affinity PD-L1-specific nanobodies (Nbs). We generated and characterized 37 Nbs recognizing mouse PD-L1. Among those, four Nbs C3, C7, E2 and E4 were selected and evaluated for preclinical imaging of PD-L1 in syngeneic mice. We performed SPECT/CT imaging in wild type versus PD-L1 knock-out mice, using Technetium-99m (99mTc) labeled Nbs. Nb C3 and E2 showed specific antigen binding and beneficial biodistribution. Through the use of CRISPR/Cas9 PD-L1 knock-out TC-1 lung epithelial cell lines, we demonstrate that SPECT/CT imaging using Nb C3 and E2 identifies PD-L1 expressing tumors, but not PD-L1 non-expressing tumors, thereby confirming the diagnostic potential of the selected Nbs. In conclusion, these data show that Nbs C3 and E2 can be used to non-invasively image PD-L1 levels in the tumor, with the strength of the signal correlating with PD-L1 levels. These findings warrant further research into the use of Nbs as a tool to image inhibitory signals in the tumor environment.

+ View Abstract

Oncotarget, 8, 1949-2553, , 2017

PMID:28410210

Open Access

Different Immunological Pathways Underlie the Immune Response to Pneumococcal Polysaccharides.
Moens L, Picard C, Shahrooei M, Wuyts G, Liston A, Fischer A, Bossuyt X

Journal of clinical immunology, 37, 1573-2592, , 2017

PMID:28303442

No Effect of Dietary Aspartame or Stevia on Pancreatic Acinar Carcinoma Development, Growth, or Induced Mortality in a Murine Model.
Dooley J, Lagou V, Dresselaers T, van Dongen KA, Himmelreich U, Liston A

Pancreatic cancer has an extremely poor prognosis, largely due to a poor record for early detection. Known risk factors for pancreatic cancer include obesity, diet, and diabetes, implicating glucose consumption and regulation as a key player. The role of artificial sweeteners may therefore be pertinent to disease kinetics. The oncogenic impact of artificial sweeteners is a highly controversial area. Aspartame, one of the most studied food additives, is widely recognized as being generally safe, although there are still specific areas where research is incomplete due to study limitations. Stevia, by contrast, has been the subject of relatively few studies, and the potential health benefits are based on extrapolation rather than direct testing. Here, we used longitudinal tracking of pancreatic acinar carcinoma development, growth, and lethality in a sensitized mouse model. Despite exposure to aspartame and stevia from the stage onward, we found no disease modification activity, in either direction. These results contribute to the data on aspartame and stevia safety, while also reducing confidence in several of the purported health benefits.

+ View Abstract

Frontiers in oncology, 7, 2234-943X, , 2017

PMID:28232906

Open Access

Cytotoxic T-lymphocyte-associated protein 4-Ig effectively controls immune activation and inflammatory disease in a novel murine model of leaky severe combined immunodeficiency.
Humblet-Baron S, Schönefeldt S, Garcia-Perez JE, Baron F, Pasciuto E, Liston A

Severe combined immunodeficiency can be caused by loss-of-function mutations in genes involved in the DNA recombination machinery, such as recombination-activating gene 1 (RAG1), RAG2, or DNA cross-link repair 1C (DCLRE1C). Defective DNA recombination causes a developmental block in T and B cells, resulting in high susceptibility to infections. Hypomorphic mutations in the same genes can also give rise to a partial loss of T cells in a spectrum including leaky severe combined immunodeficiency (LS) and Omenn syndrome (OS). These patients not only experience life-threatening infections because of immunodeficiency but also experience inflammatory/autoimmune conditions caused by the presence of autoreactive T cells.

+ View Abstract

The Journal of allergy and clinical immunology, 140, 1097-6825, , 2017

PMID:28185879

Open Access

Homeostasis-altering molecular processes as mechanisms of inflammasome activation.
Liston A, Masters SL

The innate immune system uses a distinct set of germline-encoded pattern recognition receptors (PRRs) to initiate downstream inflammatory cascades. This recognition system is in stark contrast to the adaptive immune system, which relies on highly variable, randomly generated antigen receptors. A key limitation of the innate immune system's reliance on fixed PRRs is its inflexibility in responding to rapidly evolving pathogens. Recent advances in our understanding of inflammasome activation suggest that the innate immune system also has sophisticated mechanisms for responding to pathogens for which there is no fixed PRR. This includes the recognition of debris from dying cells, known as danger-associated molecular patterns (DAMPs), which can directly activate PRRs in a similar manner to pathogen-associated molecular patterns (PAMPs). Distinct from this, emerging data for the inflammasome components NLRP3 (NOD-, LRR- and pyrin domain-containing 3) and pyrin suggest that they do not directly detect molecular patterns, but instead act as signal integrators that are capable of detecting perturbations in cytoplasmic homeostasis, for example, as initiated by infection. Monitoring these perturbations, which we term 'homeostasis-altering molecular processes' (HAMPs), provides potent flexibility in the capacity of the innate immune system to detect evolutionarily novel infections; however, HAMP sensing may also underlie the sterile inflammation that drives chronic inflammatory diseases.

+ View Abstract

Nature reviews. Immunology, 17, 1474-1741, , 2017

PMID:28163301

Defective germinal center B-cell response and reduced arthritic pathology in microRNA-29a-deficient mice.
van Nieuwenhuijze A, Dooley J, Humblet-Baron S, Sreenivasan J, Koenders M, Schlenner SM, Linterman M, Liston A

MicroRNA (miR) are short non-coding RNA sequences of 19-24 nucleotides that regulate gene expression by binding to mRNA target sequences. The miR-29 family of miR (miR-29a, b-1, b-2 and c) is a key player in T-cell differentiation and effector function, with deficiency causing thymic involution and a more inflammatory T-cell profile. However, the relative roles of different miR-29 family members in these processes have not been dissected. We studied the immunological role of the individual members of the miR-29 family using mice deficient for miR-29a/b-1 or miR-29b-2/c in homeostasis and during collagen-induced arthritis. We found a definitive hierarchy of immunological function, with the strong phenotype of miR-29a-deficiency in thymic involution and T-cell activation being reduced or absent in miR-29c-deficient mice. Strikingly, despite elevating the Th1 and Th17 responses, loss of miR-29a conferred near-complete protection from collagen-induced arthritis (CIA), with profound defects in B-cell proliferation and antibody production. Our results identify the hierarchical structure of the miR-29 family in T-cell biology, and identify miR-29a in B cells as a potential therapeutic target in arthritis.

+ View Abstract

Cellular and molecular life sciences : CMLS, , 1420-9071, , 2017

PMID:28124096

Beta-Cell Fragility As a Common Underlying Risk Factor in Type 1 and Type 2 Diabetes.
Liston A, Todd JA, Lagou V

Type 1 and type 2 diabetes are distinct clinical entities primarily driven by autoimmunity and metabolic dysfunction, respectively. However, there is a growing appreciation that they may share an etiopathological factor, namely the role of variation in beta-cell sensitivity to stress factors. Increased sensitivity increases the risk of beta-cell death or insulin secretion dysfunction. The beta-cell fragility model proposes that this variation contributes to the risk of developing either type 1 or type 2 diabetes, in the presence of immunological and/or metabolic stress factors. Therapeutics that increase the resistance of beta cells to these factors and decreasing fragility may constitute a new class of anti-diabetogenics, with potential use across both diseases.

+ View Abstract

Trends in molecular medicine, 23, 1471-499X, , 2017

PMID:28117227

Irf4 Expression in Thymic Epithelium Is Critical for Thymic Regulatory T Cell Homeostasis.
Haljasorg U, Dooley J, Laan M, Kisand K, Bichele R, Liston A, Peterson P

The thymus is a primary lymphoid organ required for the induction and maintenance of central tolerance. The main function of the thymus is to generate an immunocompetent set of T cells not reactive to self. During negative selection in the thymus, thymocytes with autoreactive potential are either deleted or differentiated into regulatory T cells (Tregs). The molecular basis by which the thymus allows high-efficiency Treg induction remains largely unknown. In this study, we report that IFN regulatory factor 4 (Irf4) is highly expressed in murine thymic epithelium and is required to prime thymic epithelial cells (TEC) for effective Treg induction. TEC-specific Irf4 deficiency resulted in a significantly reduced thymic Treg compartment and increased susceptibility to mononuclear infiltrations in the salivary gland. We propose that Irf4 is imperative for thymic Treg homeostasis because it regulates TEC-specific expression of several chemokines and costimulatory molecules indicated in thymocyte development and Treg induction.

+ View Abstract

Journal of immunology (Baltimore, Md. : 1950), 198, 1550-6606, , 2017

PMID:28108558

Open Access

A novel kindred with inherited STAT2 deficiency and severe viral illness.
Moens L, Van Eyck L, Jochmans D, Mitera T, Frans G, Bossuyt X, Matthys P, Neyts J, Ciancanelli M, Zhang SY, Gijsbers R, Casanova JL, Boisson-Dupuis S, Meyts I, Liston A

The Journal of allergy and clinical immunology, 139, 1097-6825, , 2017

PMID:28087227

miR-17∼92 family clusters control iNKT cell ontogenesis via modulation of TGF-β signaling.
Fedeli M, Riba M, Garcia Manteiga JM, Tian L, Viganò V, Rossetti G, Pagani M, Xiao C, Liston A, Stupka E, Cittaro D, Abrignani S, Provero P, Dellabona P, Casorati G

Invariant natural killer T cells (iNKT) cells are T lymphocytes displaying innate effector functions, acquired through a distinct thymic developmental program regulated by microRNAs (miRNAs). Deleting miRNAs by Dicer ablation (Dicer KO) in thymocytes selectively impairs iNKT cell survival and functional differentiation. To unravel this miRNA-dependent program, we systemically identified transcripts that were differentially expressed between WT and Dicer KO iNKT cells at different differentiation stages and predicted to be targeted by the iNKT cell-specific miRNAs. TGF-β receptor II (TGF-βRII), critically implicated in iNKT cell differentiation, was found up-regulated in iNKT Dicer KO cells together with enhanced TGF-β signaling. miRNA members of the miR-17∼92 family clusters were predicted to target Tgfbr2 mRNA upon iNKT cell development. iNKT cells lacking all three miR-17∼92 family clusters (miR-17∼92, miR-106a∼363, miR-106b∼25) phenocopied both increased TGF-βRII expression and signaling, and defective effector differentiation, displayed by iNKT Dicer KO cells. Consistently, genetic ablation of TGF-β signaling in the absence of miRNAs rescued iNKT cell differentiation. These results elucidate the global impact of miRNAs on the iNKT cell developmental program and uncover the targeting of a lineage-specific cytokine signaling by miRNAs as a mechanism regulating innate-like T-cell development and effector differentiation.

+ View Abstract

Proceedings of the National Academy of Sciences of the United States of America, 113, 1091-6490, , 2016

PMID:27930306

Open Access

Expression Diversity Adds Richness to T Cell Populations.
Franckaert D, Liston A

Variation in protein expression is a feature of all cell populations. Using T cell subsets as a proof-of-concept, Lu et al. (2016) develop a framework for dissecting out the contributors to this cell-to-cell expression variation from high-parameter flow cytometry studies.

+ View Abstract

Immunity, 45, 1097-4180, , 2016

PMID:27851924

Open Access

Inflammatory Gene Expression Profile and Defective Interferon-γ and Granzyme K in Natural Killer Cells From Systemic Juvenile Idiopathic Arthritis Patients.
Put K, Vandenhaute J, Avau A, van Nieuwenhuijze A, Brisse E, Dierckx T, Rutgeerts O, Garcia-Perez JE, Toelen J, Waer M, Leclercq G, Goris A, Van Weyenbergh J, Liston A, De Somer L, Wouters CH, Matthys P

Systemic juvenile idiopathic arthritis (JIA) is an immunoinflammatory disease characterized by arthritis and systemic manifestations. The role of natural killer (NK) cells in the pathogenesis of systemic JIA remains unclear. The purpose of this study was to perform a comprehensive analysis of NK cell phenotype and functionality in patients with systemic JIA.

+ View Abstract

Arthritis & rheumatology (Hoboken, N.J.), 69, 2326-5205, , 2017

PMID:27696741

Open Access

Shaping Variation in the Human Immune System.
Liston A, Carr EJ, Linterman MA

Immune responses demonstrate a high level of intra-species variation, compensating for the specialization capacity of pathogens. The recent advent of in-depth immune phenotyping projects in large-scale cohorts has allowed a first look into the factors that shape the inter-individual diversity of the human immune system. Genetic approaches have identified genetic diversity as drivers of 20-40% of the variation between the immune systems of individuals. The remaining 60-80% is shaped by intrinsic factors, with age being the predominant factor, as well as by environmental influences, where cohabitation and chronic viral infections were identified as key mediators. We review and integrate the recent in-depth large-scale studies on human immune diversity and its potential impact on health. VIDEO ABSTRACT.

+ View Abstract

Trends in immunology, , 1471-4981, , 2016

PMID:27693120

Shaping Variation in the Human Immune System.
Liston A, Carr EJ, Linterman MA

Immune responses demonstrate a high level of intra-species variation, compensating for the specialization capacity of pathogens. The recent advent of in-depth immune phenotyping projects in large-scale cohorts has allowed a first look into the factors that shape the inter-individual diversity of the human immune system. Genetic approaches have identified genetic diversity as drivers of 20-40% of the variation between the immune systems of individuals. The remaining 60-80% is shaped by intrinsic factors, with age being the predominant factor, as well as by environmental influences, where cohabitation and chronic viral infections were identified as key mediators. We review and integrate the recent in-depth large-scale studies on human immune diversity and its potential impact on health. VIDEO ABSTRACT.

+ View Abstract

Trends in immunology, 37, 1471-4981, , 2016

PMID:27692231

Homozygous N-terminal missense mutation in TRNT1 leads to progressive B-cell immunodeficiency in adulthood.
Frans G, Moens L, Schaballie H, Wuyts G, Liston A, Poesen K, Janssens A, Rice GI, Crow YJ, Meyts I, Bossuyt X

The Journal of allergy and clinical immunology, 139, 1097-6825, , 2017

PMID:27531075

Genetic ablation of IP3 receptor 2 increases cytokines and decreases survival of SOD1G93A mice.
Staats KA, Humblet-Baron S, Bento-Abreu A, Scheveneels W, Nikolaou A, Deckers K, Lemmens R, Goris A, Van Ginderachter JA, Van Damme P, Hisatsune C, Mikoshiba K, Liston A, Robberecht W, Van Den Bosch L

Amyotrophic lateral sclerosis (ALS) is a devastating progressive neurodegenerative disease characterized by the selective death of motor neurons. Disease pathophysiology is complex and not yet fully understood. Higher gene expression of the inositol 1,4,5-trisphosphate receptor 2 gene (ITPR2), encoding the IP receptor 2 (IPR2), was detected in sporadic ALS patients. Here, we demonstrate that IPR2 gene expression was also increased in spinal cords of ALS mice. Moreover, an increase of IPR2 expression was observed in other models of chronic and acute neurodegeneration. Upregulation of IPR2 gene expression could be induced by lipopolysaccharide (LPS) in murine astrocytes, murine macrophages and human fibroblasts indicating that it may be a compensatory response to inflammation. Preventing this response by genetic deletion of ITPR2 from SOD1 mice had a dose-dependent effect on disease duration, resulting in a significantly shorter lifespan of these mice. In addition, the absence of IPR2 led to increased innate immunity, which may contribute to the decreased survival of the SOD1 mice. Besides systemic inflammation, IPR2 knockout mice also had increased IFNγ, IL-6 and IL1α expression. Altogether, our data indicate that IPR2 protects against the negative effects of inflammation, suggesting that the increase in IPR2 expression in ALS patients is a protective response.

+ View Abstract

Human molecular genetics, 25, 1460-2083, , 2016

PMID:27378687

Open Access

Immunologic profiles of multiple sclerosis treatments reveal shared early B cell alterations.
Dooley J, Pauwels I, Franckaert D, Smets I, Garcia-Perez JE, Hilven K, Danso-Abeam D, Terbeek J, Nguyen AT, De Muynck L, Decallonne B, Dubois B, Liston A, Goris A

We undertook a systems immunology approach of the adaptive immune system in multiple sclerosis (MS), overcoming tradeoffs between scale and level of detail, in order to identify the immunologic signature of MS and the changes wrought by current immunomodulatory treatments.

+ View Abstract

Neurology(R) neuroimmunology & neuroinflammation, 3, 2332-7812, , 2016

PMID:27231713

Open Access

Neuro-immune interactions in chemical-induced airway hyperreactivity.
Devos FC, Boonen B, Alpizar YA, Maes T, Hox V, Seys S, Pollaris L, Liston A, Nemery B, Talavera K, Hoet PH, Vanoirbeek JA

Asthma may be induced by chemical sensitisers, via mechanisms that are still poorly understood. This type of asthma is characterised by airway hyperreactivity (AHR) and little airway inflammation. Since potent chemical sensitisers, such as toluene-2,4-diisocyanate (TDI), are also sensory irritants, it is suggested that chemical-induced asthma relies on neuro-immune mechanisms.We investigated the involvement of transient receptor potential channels (TRP) A1 and V1, major chemosensors in the airways, and mast cells, known for their ability to communicate with sensory nerves, in chemical-induced AHR.In vitro intracellular calcium imaging and patch-clamp recordings in TRPA1- and TRPV1-expressing Chinese hamster ovarian cells showed that TDI activates murine TRPA1, but not TRPV1. Using an in vivo model, in which an airway challenge with TDI induces AHR in TDI-sensitised C57Bl/6 mice, we demonstrated that AHR does not develop, despite successful sensitisation, in Trpa1 and Trpv1 knockout mice, and wild-type mice pretreated with a TRPA1 blocker or a substance P receptor antagonist. TDI-induced AHR was also abolished in mast cell deficient Kit(Wsh) (/Wsh) mice, and in wild-type mice pretreated with the mast cell stabiliser ketotifen, without changes in immunological parameters.These data demonstrate that TRPA1, TRPV1 and mast cells play an indispensable role in the development of TDI-elicited AHR.

+ View Abstract

The European respiratory journal, 48, 1399-3003, , 2016

PMID:27126687

Open Access

TCR transgenic mice reveal the impact of type 1 diabetes loci on early and late disease checkpoints.
Hillhouse EE, Liston A, Collin R, Desautels E, Goodnow CC, Lesage S

Linkage analysis studies for autoimmune diabetes have revealed multiple non-major histocompatibility complex (MHC) chromosomal regions linked to disease susceptibility. To date, more than 20 insulin-dependent diabetes (Idd) loci linked to diabetes susceptibility have been identified in NOD mice and validated via congenic breeding. Importantly, evidence suggests that Idd loci may regulate at least two pathological steps during autoimmune diabetes development, namely the onset of insulitis and the transition from insulitis to overt diabetes. Here we assess the role of various non-MHC Idd diabetes-resistance loci, which have been validated in the non-transgenic setting, on autoimmune diabetes progression in the transgenic setting. Specifically, we generated multiple Idd congenic strains in the 3A9-TCR:insHEL NOD.H2(k) transgenic model and monitored their diabetes incidence. We show that 3A9-TCR:insHEL NOD.H2(k) mice congenic for Idd3 or Idd5 display a reduction in diabetes development, whereas mice congenic for Idd9 or Idd13 exhibit an increase, in comparison with 3A9-TCR:insHEL NOD.H2(k) mice. These results suggest that the presence of the 3A9-TCR and hen egg lysosyme transgenes can offset the regulatory function of certain diabetes-resistance genetic variants contained within the Idd loci, including Idd9 and Idd13. We propose the antigen-specific 3A9-TCR:insHEL transgenic model as a useful tool for the study of the genetics of autoimmune diabetes development.

+ View Abstract

Immunology and cell biology, 94, 1440-1711, , 2016

PMID:27046082

Familial autoinflammation with neutrophilic dermatosis reveals a regulatory mechanism of pyrin activation.
Masters SL, Lagou V, Jéru I, Baker PJ, Van Eyck L, Parry DA, Lawless D, De Nardo D, Garcia-Perez JE, Dagley LF, Holley CL, Dooley J, Moghaddas F, Pasciuto E, Jeandel PY, Sciot R, Lyras D, Webb AI, Nicholson SE, De Somer L, van Nieuwenhove E, Ruuth-Praz J, Copin B, Cochet E, Medlej-Hashim M, Megarbane A, Schroder K, Savic S, Goris A, Amselem S, Wouters C, Liston A

Pyrin responds to pathogen signals and loss of cellular homeostasis by forming an inflammasome complex that drives the cleavage and secretion of interleukin-1β (IL-1β). Mutations in the B30.2/SPRY domain cause pathogen-independent activation of pyrin and are responsible for the autoinflammatory disease familial Mediterranean fever (FMF). We studied a family with a dominantly inherited autoinflammatory disease, distinct from FMF, characterized by childhood-onset recurrent episodes of neutrophilic dermatosis, fever, elevated acute-phase reactants, arthralgia, and myalgia/myositis. The disease was caused by a mutation in MEFV, the gene encoding pyrin (S242R). The mutation results in the loss of a 14-3-3 binding motif at phosphorylated S242, which was not perturbed by FMF mutations in the B30.2/SPRY domain. However, loss of both S242 phosphorylation and 14-3-3 binding was observed for bacterial effectors that activate the pyrin inflammasome, such as Clostridium difficile toxin B (TcdB). The S242R mutation thus recapitulated the effect of pathogen sensing, triggering inflammasome activation and IL-1β production. Successful therapy targeting IL-1β has been initiated in one patient, resolving pyrin-associated autoinflammation with neutrophilic dermatosis. This disease provides evidence that a guard-like mechanism of pyrin regulation, originally identified for Nod-like receptors in plant innate immunity, also exists in humans.

+ View Abstract

Science translational medicine, 8, 1946-6242, , 2016

PMID:27030597

Open Access

Genetic predisposition for beta cell fragility underlies type 1 and type 2 diabetes.
Dooley J, Tian L, Schonefeldt S, Delghingaro-Augusto V, Garcia-Perez JE, Pasciuto E, Di Marino D, Carr EJ, Oskolkov N, Lyssenko V, Franckaert D, Lagou V, Overbergh L, Vandenbussche J, Allemeersch J, Chabot-Roy G, Dahlstrom JE, Laybutt DR, Petrovsky N, Socha L, Gevaert K, Jetten AM, Lambrechts D, Linterman MA, Goodnow CC, Nolan CJ, Lesage S, Schlenner SM, Liston A

Type 1 (T1D) and type 2 (T2D) diabetes share pathophysiological characteristics, yet mechanistic links have remained elusive. T1D results from autoimmune destruction of pancreatic beta cells, whereas beta cell failure in T2D is delayed and progressive. Here we find a new genetic component of diabetes susceptibility in T1D non-obese diabetic (NOD) mice, identifying immune-independent beta cell fragility. Genetic variation in Xrcc4 and Glis3 alters the response of NOD beta cells to unfolded protein stress, enhancing the apoptotic and senescent fates. The same transcriptional relationships were observed in human islets, demonstrating the role of beta cell fragility in genetic predisposition to diabetes.

+ View Abstract

Nature genetics, 48, 1546-1718, , 2016

PMID:26998692

Open Access

IL-2 consumption by highly activated CD8 T cells induces regulatory T-cell dysfunction in patients with hemophagocytic lymphohistiocytosis.
Humblet-Baron S, Franckaert D, Dooley J, Bornschein S, Cauwe B, Schönefeldt S, Bossuyt X, Matthys P, Baron F, Wouters C, Liston A

Hemophagocytic lymphohistiocytosis (HLH) is a severe inflammatory condition driven by excessive CD8(+) T-cell activation. HLH occurs as both acquired and familial hemophagocytic lymphohistiocytosis (FHL) forms. In both conditions, a sterile or infectious trigger is required for disease initiation, which then becomes self-sustaining and life-threatening. Recent studies have attributed the key distal event to excessive IFN-γ production; however, the proximal events driving immune dysregulation have remained undefined.

+ View Abstract

The Journal of allergy and clinical immunology, 138, 1097-6825, , 2016

PMID:26947179

Open Access

The cellular composition of the human immune system is shaped by age and cohabitation.
Carr EJ, Dooley J, Garcia-Perez JE, Lagou V, Lee JC, Wouters C, Meyts I, Goris A, Boeckxstaens G, Linterman MA, Liston A

Detailed population-level description of the human immune system has recently become achievable. We used a 'systems-level' approach to establish a resource of cellular immune profiles of 670 healthy individuals. We report a high level of interindividual variation, with low longitudinal variation, at the level of cellular subset composition of the immune system. Despite the profound effects of antigen exposure on individual antigen-specific clones, the cellular subset structure proved highly elastic, with transient vaccination-induced changes followed by a return to the individual's unique baseline. Notably, the largest influence on immunological variation identified was cohabitation, with 50% less immunological variation between individuals who share an environment (as parents) than between people in the wider population. These results identify local environmental conditions as a key factor in shaping the human immune system.

+ View Abstract

Nature immunology, , 1529-2916, , 2016

PMID:26878114

Open Access

Phenotypic variability in patients with ADA2 deficiency due to identical homozygous R169Q mutations.
Van Montfrans JM, Hartman EA, Braun KP, Hennekam EA, Hak EA, Nederkoorn PJ, Westendorp WF, Bredius RG, Kollen WJ, Schölvinck EH, Legger GE, Meyts I, Liston A, Lichtenbelt KD, Giltay JC, Van Haaften G, De Vries Simons GM, Leavis H, Sanders CJ, Bierings MB, Nierkens S, Van Gijn ME

To determine the genotype-phenotype association in patients with adenosine deaminase-2 (ADA2) deficiency due to identical homozygous R169Q mutations inCECR1 METHODS: We present a case series of nine ADA2-deficient patients with an identical homozygous R169Q mutation. Clinical and diagnostic data were collected and available MRI studies were reviewed. We performed genealogy and haplotype analyses and measured serum ADA2 activity. ADA2 activity values were correlated to clinical symptoms.

+ View Abstract

Rheumatology (Oxford, England), 55, 1462-0332, , 2016

PMID:26867732

Histamine Receptor H1-Mediated Sensitization of TRPV1 Mediates Visceral Hypersensitivity and Symptoms in Patients With Irritable Bowel Syndrome.
Wouters MM, Balemans D, Van Wanrooy S, Dooley J, Cibert-Goton V, Alpizar YA, Valdez-Morales EE, Nasser Y, Van Veldhoven PP, Vanbrabant W, Van der Merwe S, Mols R, Ghesquière B, Cirillo C, Kortekaas I, Carmeliet P, Peetermans WE, Vermeire S, Rutgeerts P, Augustijns P, Hellings PW, Belmans A, Vanner S, Bulmer DC, Talavera K, Vanden Berghe P, Liston A, Boeckxstaens GE

Histamine sensitizes the nociceptor transient reporter potential channel V1 (TRPV1) and has been shown to contribute to visceral hypersensitivity in animals. We investigated the role of TRPV1 in irritable bowel syndrome (IBS) and evaluated if an antagonist of histamine receptor H1 (HRH1) could reduce symptoms of patients in a randomized placebo-controlled trial.

+ View Abstract

Gastroenterology, 150, 1528-0012, , 2016

PMID:26752109

Mild humoral immunodeficiency in a patient with X-linked Kabuki syndrome.
Frans G, Meyts I, Devriendt K, Liston A, Vermeulen F, Bossuyt X

American journal of medical genetics. Part A, 170, 1552-4833, , 2016

PMID:26701671

The microRNA-29 Family Dictates the Balance Between Homeostatic and Pathological Glucose Handling in Diabetes and Obesity.
Dooley J, Garcia-Perez JE, Sreenivasan J, Schlenner SM, Vangoitsenhoven R, Papadopoulou AS, Tian L, Schonefeldt S, Serneels L, Deroose C, Staats KA, Van der Schueren B, De Strooper B, McGuinness OP, Mathieu C, Liston A

The microRNA-29 (miR-29) family is among the most abundantly expressed microRNA in the pancreas and liver. Here, we investigated the function of miR-29 in glucose regulation using miR-29a/b-1 (miR-29a)-deficient mice and newly generated miR-29b-2/c (miR-29c)-deficient mice. We observed multiple independent functions of the miR-29 family, which can be segregated into a hierarchical physiologic regulation of glucose handling. miR-29a, and not miR-29c, was observed to be a positive regulator of insulin secretion in vivo, with dysregulation of the exocytotic machinery sensitizing β-cells to overt diabetes after unfolded protein stress. By contrast, in the liver both miR-29a and miR-29c were important negative regulators of insulin signaling via phosphatidylinositol 3-kinase regulation. Global or hepatic insufficiency of miR-29 potently inhibited obesity and prevented the onset of diet-induced insulin resistance. These results demonstrate strong regulatory functions for the miR-29 family in obesity and diabetes, culminating in a hierarchical and dose-dependent effect on premature lethality.

+ View Abstract

Diabetes, 65, 1939-327X, , 2016

PMID:26696639

Open Access

The Molecular Control of Regulatory T Cell Induction.
van Nieuwenhuijze A, Liston A

Regulatory T cells (Tregs) are characterized by the expression of the master transcription factor forkhead box P3 (Foxp3). Although Foxp3 expression is widely used as a marker of the Treg lineage, recent data show that the Treg fate is determined by a multifactorial signaling pathway, involving cytokines, nuclear factors, and epigenetic modifications. Foxp3 expression and the Treg phenotype can be acquired by T cells in the periphery, illustrating that the Treg fate is not necessarily conferred during thymic development. The two main Treg populations in vivo, thymic Tregs and peripheral Tregs, differ in the pathways followed for their maturation. This chapter discusses the molecular control of Treg induction, in the thymus as well as the periphery.

+ View Abstract

Progress in molecular biology and translational science, 136, 1878-0814, , 2015

PMID:26615093

Noninvasive Imaging Reveals Stable Transgene Expression in Mouse Airways After Delivery of a Nonintegrating Recombinant Adeno-Associated Viral Vector.
Vidović D, Gijsbers R, Quiles-Jimenez A, Dooley J, Van den Haute C, Van der Perren A, Liston A, Baekelandt V, Debyser Z, Carlon MS

Gene therapy holds promise to cure a wide range of genetic and acquired diseases. Recent successes in recombinant adeno-associated viral vector (rAAV)-based gene therapy in the clinic for hereditary disorders such as Leber's congenital amaurosis and hemophilia B encouraged us to reexplore an rAAV approach for pulmonary gene transfer. Only limited clinical successes have been achieved for airway gene transfer so far, underscoring the need for further preclinical development of rAAV-based gene therapy for pulmonary disorders. We sought to determine the preclinical potential of an airway-tropic serotype, rAAV2/5, encoding reporter genes when delivered to mouse airways. Although several groups have assessed the stability of gene transfer using a nonintegrating rAAV in mouse airways, long-term stability for more than a year has not been reported. Additionally, an extensive quantitative analysis of the specific cell types targeted by rAAV2/5 using cell-specific markers is lacking. We obtained sustained gene expression in upper and lower airways up to 15 months after vector administration, a substantial proportion of the lifespan of a laboratory mouse. In addition, we demonstrated that readministration of rAAV2/5 to the airways is feasible and increases gene expression 14 months after primary vector administration, despite the presence of circulating neutralizing antibodies. Finally, identification of transduced cell types revealed different subpopulations being targeted by rAAV2/5, with 64% of β-galactosidase-positive cells being ciliated cells, 34% club cells in the conducting airways, and 75% alveolar type II cells in the alveoli at 1 month postinjection. This underscores the therapeutic potential of a nonintegrating rAAV vector to develop a gene therapeutic drug for a variety of pulmonary disorders, such as cystic fibrosis, primary ciliary dyskinesia, and surfactant deficiencies.

+ View Abstract

Human gene therapy, 27, 1557-7422, , 2016

PMID:26567984

CCR2 defines in vivo development and homing of IL-23-driven GM-CSF-producing Th17 cells.
Kara EE, McKenzie DR, Bastow CR, Gregor CE, Fenix KA, Ogunniyi AD, Paton JC, Mack M, Pombal DR, Seillet C, Dubois B, Liston A, MacDonald KP, Belz GT, Smyth MJ, Hill GR, Comerford I, McColl SR

IL-17-producing helper T (Th17) cells are critical for host defense against extracellular pathogens but also drive numerous autoimmune diseases. Th17 cells that differ in their inflammatory potential have been described including IL-10-producing Th17 cells that are weak inducers of inflammation and highly inflammatory, IL-23-driven, GM-CSF/IFNγ-producing Th17 cells. However, their distinct developmental requirements, functions and trafficking mechanisms in vivo remain poorly understood. Here we identify a temporally regulated IL-23-dependent switch from CCR6 to CCR2 usage by developing Th17 cells that is critical for pathogenic Th17 cell-driven inflammation in experimental autoimmune encephalomyelitis (EAE). This switch defines a unique in vivo cell surface signature (CCR6(-)CCR2(+)) of GM-CSF/IFNγ-producing Th17 cells in EAE and experimental persistent extracellular bacterial infection, and in humans. Using this signature, we identify an IL-23/IL-1/IFNγ/TNFα/T-bet/Eomesodermin-driven circuit driving GM-CSF/IFNγ-producing Th17 cell formation in vivo. Thus, our data identify a unique cell surface signature, trafficking mechanism and T-cell intrinsic regulators of GM-CSF/IFNγ-producing Th17 cells.

+ View Abstract

Nature communications, 6, 2041-1723, , 2015

PMID:26511769

Open Access

DNA methylation profiling of non-small cell lung cancer reveals a COPD-driven immune-related signature.
Wauters E, Janssens W, Vansteenkiste J, Decaluwé H, Heulens N, Thienpont B, Zhao H, Smeets D, Sagaert X, Coolen J, Decramer M, Liston A, De Leyn P, Moisse M, Lambrechts D

Non-small cell lung cancer (NSCLC) is a heterogeneous disorder consisting of distinct molecular subtypes each characterised by specific genetic and epigenetic profiles. Here, we aimed to identify novel NSCLC subtypes based on genome-wide methylation data, assess their relationship with smoking behaviour, age, COPD, emphysema and tumour histopathology, and identify the molecular pathways underlying each subtype.

+ View Abstract

Thorax, 70, 1468-3296, , 2015

PMID:26349763

Psychological comorbidity increases the risk for postinfectious IBS partly by enhanced susceptibility to develop infectious gastroenteritis.
Wouters MM, Van Wanrooy S, Nguyen A, Dooley J, Aguilera-Lizarraga J, Van Brabant W, Garcia-Perez JE, Van Oudenhove L, Van Ranst M, Verhaegen J, Liston A, Boeckxstaens G

Psychological factors increase the risk to develop postinfectious IBS (PI-IBS), but the mechanisms involved are unclear. As stress affects the immune system, we investigated the potential interaction between psychological factors, the immune response against infectious gastroenteritis (IGE) and the development of IGE and PI-IBS in a large cohort exposed to contaminated drinking water.

+ View Abstract

Gut, 65, 1468-3288, , 2016

PMID:26071133

The thymoprotective function of leptin is indirectly mediated via suppression of obesity.
Sreenivasan J, Schlenner S, Franckaert D, Dooley J, Liston A

Leptin is an adipokine that regulates metabolism and plays an important role as a neuroendocrine hormone. Leptin mediates these functions via the leptin receptor, and deficiency in either leptin or its receptor leads to obesity in humans and mice. Leptin has far reaching effects on the immune system, as observed in obese mice, which display decreased thymic function and increased inflammatory responses. With expression of the leptin receptor on T cells and supporting thymic epithelium, aberrant signalling through the leptin receptor has been thought to be the direct cause of thymic involution in obese mice. Here, we demonstrate that the absence of leptin receptor on either thymic epithelial cells or T cells does not lead to the loss of thymic function, demonstrating that the thymoprotective effect of leptin is mediated by obesity suppression rather than direct signalling to the cellular components of the thymus.

+ View Abstract

Immunology, 146, 1365-2567, , 2015

PMID:26059465

Open Access

Humoral autoimmunity: a failure of regulatory T cells?
Dhaeze T, Stinissen P, Liston A, Hellings N

Regulatory T cells (Tregs) are essential in maintaining tolerance to self. Several lines of evidence indicate that Tregs are functionally impaired in a variety of autoimmune diseases, leading to inefficient regulation of autoimmune T cells. Recent findings also suggest that Tregs are essential in controlling autoreactive B cells. The recently identified follicular regulatory T cell subset (TFR) is thought to regulate the production of autoantibodies in the germinal center (GC) response. Here we provide an update on the role of Tregs in controlling the GC response, and whether defective control over B cell tolerance contributes to autoimmunity.

+ View Abstract

Autoimmunity reviews, 14, 1873-0183, , 2015

PMID:25913138

Lpr-induced systemic autoimmunity is unaffected by mast cell deficiency.
van Nieuwenhuijze AE, Cauwe B, Klatt D, Humblet-Baron S, Liston A

The function of mast cells in allergic and organ-specific autoimmune responses is highly controversial. In the current study, we aimed to dissect the role of mast cells in systemic autoimmunity in the B6(lpr/lpr) mouse, a spontaneous model of systemic lupus erythematosus. B6(lpr/lpr) mice were interbred with C57Bl/6-Kit(W-sh/W-sh) (Wsh) mice, resulting in mast cell deficiency. The offspring from this cross (Lpr/Wsh mice) developed symptoms of lupus of the same severity as B6(lpr/lpr) mice. Loss of mast cells on the Lpr background did not alter autoantibody production, proteinuria, the composition of T and B cell populations or autoimmune pathology. Reduced c-Kit expression did drive expanded splenomegaly and impeded interleukin-4 production by CD4(+) cells, suggesting minor functions for mast cells. In general, we conclude that mast cell deficiency and c-Kit deficiency do not play a role in the pathogenesis of lupus in B6(lpr/lpr) mice.

+ View Abstract

Immunology and cell biology, 93, 1440-1711, , 2015

PMID:25849740

Brief Report: IFIH1 Mutation Causes Systemic Lupus Erythematosus With Selective IgA Deficiency.
Van Eyck L, De Somer L, Pombal D, Bornschein S, Frans G, Humblet-Baron S, Moens L, de Zegher F, Bossuyt X, Wouters C, Liston A

To identify the underlying genetic defect in a 16-year-old girl with severe early-onset and refractory systemic lupus erythematosus (SLE), IgA deficiency, and mild lower limb spasticity without neuroradiologic manifestations.

+ View Abstract

Arthritis & rheumatology (Hoboken, N.J.), 67, 2326-5205, , 2015

PMID:25777993

Open Access

Regulatory T cell differentiation: cooperation saves the day.
Liston A, Schlenner SM

The EMBO journal, 34, 1460-2075, , 2015

PMID:25712479

Open Access

Transcriptional upregulation of myelin components in spontaneous myelin basic protein-deficient mice.
Staats KA, Pombal D, Schönefeldt S, Van Helleputte L, Maurin H, Dresselaers T, Govaerts K, Himmelreich U, Van Leuven F, Van Den Bosch L, Dooley J, Humblet-Baron S, Liston A

Myelin is essential for efficient signal transduction in the nervous system comprising of multiple proteins. The intricacies of the regulation of the formation of myelin, and its components, are not fully understood. Here, we describe the characterization of a novel myelin basic protein (Mbp) mutant mouse, mbp(jive), which spontaneously occurred in our mouse colony. These mice displayed the onset of a shaking gait before 3 weeks of age and seizure onset before 2 months of age. Due to a progressive increase of seizure intensity, mbp(jive) mice experienced premature lethality at around 3 months of age. Mbp mRNA transcript or protein was undetectable and, accordingly, genetic analysis demonstrated a homozygous loss of exons 3 to 6 of Mbp. Peripheral nerve conductance was mostly unimpaired. Additionally, we observed grave structural changes in white matter predominant structures were detected by T1, T2 and diffusion weighted magnetic resonance imaging. We additionally observed that Mbp-deficiency results in an upregulation of Qkl, Mag and Cnp, suggestive of a regulatory feedback mechanism whereby compensatory increases in Qkl have downstream effects on Mag and Cnp. Further research will clarify the role and specifications of this myelin feedback loop, as well as determine its potential role in therapeutic strategies for demyelinating disorders.

+ View Abstract

Brain research, 1606, 1872-6240, , 2015

PMID:25708149

Quantitative reduction of the TCR adapter protein SLP-76 unbalances immunity and immune regulation.
Siggs OM, Miosge LA, Daley SR, Asquith K, Foster PS, Liston A, Goodnow CC

Gene variants that disrupt TCR signaling can cause severe immune deficiency, yet less disruptive variants are sometimes associated with immune pathology. Null mutations of the gene encoding the scaffold protein Src homology 2 domain-containing leukocyte protein of 76 kDa (SLP-76), for example, cause an arrest of T cell positive selection, whereas a synthetic membrane-targeted allele allows limited positive selection but is associated with proinflammatory cytokine production and autoantibodies. Whether these and other enigmatic outcomes are due to a biochemical uncoupling of tolerogenic signaling, or simply a quantitative reduction of protein activity, remains to be determined. In this study we describe a splice variant of Lcp2 that reduced the amount of wild-type SLP-76 protein by ~90%, disrupting immunogenic and tolerogenic pathways to different degrees. Mutant mice produced excessive amounts of proinflammatory cytokines, autoantibodies, and IgE, revealing that simple quantitative reductions of SLP-76 were sufficient to trigger immune dysregulation. This allele reveals a dose-sensitive threshold for SLP-76 in the balance of immunity and immune dysregulation, a common disturbance of atypical clinical immune deficiencies.

+ View Abstract

Journal of immunology (Baltimore, Md. : 1950), 194, 1550-6606, , 2015

PMID:25662996

Open Access

miR-29a maintains mouse hematopoietic stem cell self-renewal by regulating Dnmt3a.
Hu W, Dooley J, Chung SS, Chandramohan D, Cimmino L, Mukherjee S, Mason CE, de Strooper B, Liston A, Park CY

Hematopoietic stem cells (HSCs) possess the ability to generate all hematopoietic cell types and to self-renew over long periods, but the mechanisms that regulate their unique properties are incompletely understood. Herein, we show that homozygous deletion of the miR-29a/b-1 bicistron results in decreased numbers of hematopoietic stem and progenitor cells (HSPCs), decreased HSC self-renewal, and increased HSC cell cycling and apoptosis. The HSPC phenotype is specifically due to loss of miR-29a, because miR-29b expression is unaltered in miR-29a/b-1-null HSCs, and only ectopic expression of miR-29a restores HSPC function both in vitro and in vivo. HSCs lacking miR-29a/b-1 exhibit widespread transcriptional dysregulation and adopt gene expression patterns similar to normal committed progenitors. A number of predicted miR-29 target genes, including Dnmt3a, are significantly upregulated in miR-29a/b-1-null HSCs. The loss of negative regulation of Dnmt3a by miR-29a is a major contributor to the miR-29a/b-1-null HSPC phenotype, as both in vitro Dnmt3a short hairpin RNA knockdown assays and a genetic haploinsufficiency model of Dnmt3a restored the frequency and long-term reconstitution capacity of HSCs from miR-29a/b-1-deficient mice. Overall, these data demonstrate that miR-29a is critical for maintaining HSC function through its negative regulation of Dnmt3a.

+ View Abstract

Blood, 125, 1528-0020, , 2015

PMID:25634742

Open Access

Premature thymic involution is independent of structural plasticity of the thymic stroma.
Franckaert D, Schlenner SM, Heirman N, Gill J, Skogberg G, Ekwall O, Put K, Linterman MA, Dooley J, Liston A

The thymus is the organ devoted to T-cell production. The thymus undergoes multiple rounds of atrophy and redevelopment before degenerating with age in a process known as involution. This process is poorly understood, despite the influence the phenomenon has on peripheral T-cell numbers. Here we have investigated the FVB/N mouse strain, which displays premature thymic involution. We find multiple architectural and cellular features that precede thymic involution, including disruption of the epithelial-endothelial relationship and a progressive loss of pro-T cells. The architectural features, reminiscent of the human thymus, are intrinsic to the non-hematopoietic compartment and are neither necessary nor sufficient for thymic involution. By contrast, the loss of pro-T cells is intrinsic to the hematopoietic compartment, and is sufficient to drive premature involution. These results identify pro-T-cell loss as the main driver of premature thymic involution, and highlight the plasticity of the thymic stroma, capable of maintaining function across diverse inter-strain architectures. This article is protected by copyright. All rights reserved.

+ View Abstract

European journal of immunology, , 1521-4141, , 2015

PMID:25627671

Open Access

How informative is the mouse for human gut microbiota research?
Nguyen TL, Vieira-Silva S, Liston A, Raes J

The microbiota of the human gut is gaining broad attention owing to its association with a wide range of diseases, ranging from metabolic disorders (e.g. obesity and type 2 diabetes) to autoimmune diseases (such as inflammatory bowel disease and type 1 diabetes), cancer and even neurodevelopmental disorders (e.g. autism). Having been increasingly used in biomedical research, mice have become the model of choice for most studies in this emerging field. Mouse models allow perturbations in gut microbiota to be studied in a controlled experimental setup, and thus help in assessing causality of the complex host-microbiota interactions and in developing mechanistic hypotheses. However, pitfalls should be considered when translating gut microbiome research results from mouse models to humans. In this Special Article, we discuss the intrinsic similarities and differences that exist between the two systems, and compare the human and murine core gut microbiota based on a meta-analysis of currently available datasets. Finally, we discuss the external factors that influence the capability of mouse models to recapitulate the gut microbiota shifts associated with human diseases, and investigate which alternative model systems exist for gut microbiota research.

+ View Abstract

Disease models & mechanisms, 8, 1754-8411, , 2015

PMID:25561744

Open Access

Promiscuous Foxp3-cre activity reveals a differential requirement for CD28 in Foxp3(+) and Foxp3(-) T cells.
Franckaert D, Dooley J, Roos E, Floess S, Huehn J, Luche H, Fehling HJ, Liston A, Linterman MA, Schlenner SM

Costimulatory signals by CD28 are critical for thymic regulatory T-cell (Treg) development. To determine the functional relevance of CD28 for peripheral Treg post thymic selection, we crossed the widely used Forkhead box protein 3 (Foxp3)-CreYFP mice to mice bearing a conditional Cd28 allele. Treg-specific CD28 deficiency provoked a severe autoimmune syndrome as a result of a strong disadvantage in competitive fitness and proliferation of CD28-deficient Tregs. By contrast, Treg survival and lineage integrity were not affected by the lack of CD28. This data demonstrate that, even after the initial induction requirement, Treg maintain a higher dependency on CD28 signalling than conventional T cells for homeostasis. In addition, we found the Foxp3-CreYFP allele to be a hypomorph, with reduced Foxp3 protein levels. Furthermore, we report here the stochastic activity of the Foxp3-CreYFP allele in non-Tregs, sufficient to recombine some conditional alleles (including Cd28) but not others (including R26-RFP). This hypomorphism and 'leaky' expression of the Foxp3-CreYFP allele should be considered when analysing the conditionally mutated Treg.Immunology and Cell Biology advance online publication, 23 December 2014; doi:10.1038/icb.2014.108.

+ View Abstract

Immunology and cell biology, , 1440-1711, , 2014

PMID:25533288

Open Access

A new ICB sister journal focuses on clinical and translational immunology.
Belz G, Tangye SG, Liston A

Clinical & translational immunology, 1, 2050-0068, , 2012

PMID:25505946

Open Access

Hematopoietic stem cell transplantation rescues the immunologic phenotype and prevents vasculopathy in patients with adenosine deaminase 2 deficiency.
Van Eyck L, Hershfield MS, Pombal D, Kelly SJ, Ganson NJ, Moens L, Frans G, Schaballie H, De Hertogh G, Dooley J, Bossuyt X, Wouters C, Liston A, Meyts I

The Journal of allergy and clinical immunology, 135, 1097-6825, , 2015

PMID:25457153

Open Access

Deficiency of the miR-29a/b-1 cluster leads to ataxic features and cerebellar alterations in mice.
Papadopoulou AS, Serneels L, Achsel T, Mandemakers W, Callaerts-Vegh Z, Dooley J, Lau P, Ayoubi T, Radaelli E, Spinazzi M, Neumann M, Hébert SS, Silahtaroglu A, Liston A, D'Hooge R, Glatzel M, De Strooper B

miR-29 is expressed strongly in the brain and alterations in expression have been linked to several neurological disorders. To further explore the function of this miRNA in the brain, we generated miR-29a/b-1 knockout animals. Knockout mice develop a progressive disorder characterized by locomotor impairment and ataxia. The different members of the miR-29 family are strongly expressed in neurons of the olfactory bulb, the hippocampus and in the Purkinje cells of the cerebellum. Morphological analysis showed that Purkinje cells are smaller and display less dendritic arborisation compared to their wildtype littermates. In addition, a decreased number of parallel fibers form synapses on the Purkinje cells. We identified several mRNAs significantly up-regulated in the absence of the miR-29a/b-1 cluster. At the protein level, however, the voltage-gated potassium channel Kcnc3 (Kv3.3) was significantly up-regulated in the cerebella of the miR-29a/b knockout mice. Dysregulation of KCNC3 expression may contribute to the ataxic phenotype.

+ View Abstract

Neurobiology of disease, 73, 1095-953X, , 2015

PMID:25315682

Mutant ADA2 in vasculopathies.
Van Eyck L, Liston A, Wouters C

The New England journal of medicine, 371, 1533-4406, , 2014

PMID:25075848

Mutant ADA2 in vasculopathies.
Van Eyck L, Liston A, Meyts I

The New England journal of medicine, 371, 1533-4406, , 2014

PMID:25075846

Gain-of-function mutations in signal transducer and activator of transcription 1 (STAT1): chronic mucocutaneous candidiasis accompanied by enamel defects and delayed dental shedding.
Frans G, Moens L, Schaballie H, Van Eyck L, Borgers H, Wuyts M, Dillaerts D, Vermeulen E, Dooley J, Grimbacher B, Cant A, Declerck D, Peumans M, Renard M, De Boeck K, Hoffman I, François I, Liston A, Claessens F, Bossuyt X, Meyts I

The Journal of allergy and clinical immunology, 134, 1097-6825, , 2014

PMID:25042743

Open Access

Type 1 diabetes in NOD mice unaffected by mast cell deficiency.
Gutierrez DA, Fu W, Schonefeldt S, Feyerabend TB, Ortiz-Lopez A, Lampi Y, Liston A, Mathis D, Rodewald HR

Mast cells have been invoked as important players in immune responses associated with autoimmune diseases. Based on in vitro studies, or in vivo through the use of Kit mutant mice, mast cells have been suggested to play immunological roles in direct antigen presentation to both CD4(+) and CD8(+) T cells, in the regulation of T-cell and dendritic cell migration to lymph nodes, and in Th1 versus Th2 polarization, all of which could significantly impact the immune response against self-antigens in autoimmune disease, including type 1 diabetes (T1D). Until now, the role of mast cells in the onset and incidence of T1D has only been indirectly tested through the use of low-specificity mast cell inhibitors and activators, and published studies reported contrasting results. Our three laboratories have generated independently two strains of mast cell-deficient nonobese diabetic (NOD) mice, NOD.Cpa3(Cre/+) (Heidelberg) and NOD.Kit(W-sh/W-sh) (Leuven and Boston), to address the effects of mast cell deficiency on the development of T1D in the NOD strain. Our collective data demonstrate that both incidence and progression of T1D in NOD mice are independent of mast cells. Moreover, analysis of pancreatic lymph node cells indicated that lack of mast cells has no discernible effect on the autoimmune response, which involves both innate and adaptive immune components. Our results demonstrate that mast cells are not involved in T1D in the NOD strain, making their role in this process nonessential and excluding them as potential therapeutic targets.

+ View Abstract

Diabetes, 63, 1939-327X, , 2014

PMID:24917576

Open Access

Uhrf to Treg cells: reinforcing the mucosal peacekeepers.
Gray DH, Liston A

Nature immunology, 15, 1529-2916, , 2014

PMID:24840991

Immunological ignorance allows long-term gene expression after perinatal recombinant adeno-associated virus-mediated gene transfer to murine airways.
Carlon MS, Vidović D, Dooley J, da Cunha MM, Maris M, Lampi Y, Toelen J, Van den Haute C, Baekelandt V, Deprest J, Verbeken E, Liston A, Gijsbers R, Debyser Z

Gene therapy of the lung has the potential to treat life-threatening diseases such as cystic fibrosis and α(1)-antitrypsin or surfactant deficiencies. A major hurdle for successful gene therapy is the development of an immune response against the transgene and/or viral vector. We hypothesized that by targeting the airways in the perinatal period, induction of an immune response against the vector particle could be prevented because of immaturity of the immune system, in turn allowing repeated gene transfer later in adult life to ensure long-term gene expression. Therefore, we readministered recombinant adeno-associated viral vector serotype 5 (rAAV2/5) to mouse airways 3 and 6 months after initial perinatal gene transfer. Our findings demonstrate that perinatal rAAV2/5-mediated gene transfer to the airways avoids a strong immune response. This immunological ignorance allows the readministration of an autologous vector later in adult life, resulting in efficient and stable gene transfer up to 7 months, without evidence of a decrease in transgene expression. Together, these data provide a basis to further explore perinatal gene therapy for pulmonary conditions with adequate gene expression up to 7 months.

+ View Abstract

Human gene therapy, 25, 1557-7422, , 2014

PMID:24548076

Open Access

Homeostatic control of regulatory T cell diversity.
Liston A, Gray DH

Regulatory T (TReg) cells constitute an essential counterbalance to adaptive immune responses. Failure to maintain appropriate TReg cell numbers or function leads to autoimmune, malignant and immunodeficient conditions. Dynamic homeostatic processes preserve the number of forkhead box P3-expressing (FOXP3(+)) TReg cells within a healthy range, with high rates of cell division being offset by apoptosis under steady-state conditions. Recent studies have shown that TReg cells become specialized for different environmental contexts, tailoring their functions and homeostatic properties to a wide range of tissues and immune conditions. In this Review, we describe new insights into the molecular controls that maintain the steady-state homeostasis of TReg cells and the cues that drive TReg cell adaptation to inflammation and/or different locations. We highlight how differing local milieu might drive context-specific TReg cell function and restoration of immune homeostasis, and how dysregulation of these processes can precipitate disease.

+ View Abstract

Nature reviews. Immunology, 14, 1474-1741, , 2014

PMID:24481337

Systemic juvenile idiopathic arthritis-like syndrome in mice following stimulation of the immune system with Freund's complete adjuvant: regulation by interferon-γ.
Avau A, Mitera T, Put S, Put K, Brisse E, Filtjens J, Uyttenhove C, Van Snick J, Liston A, Leclercq G, Billiau AD, Wouters CH, Matthys P

Systemic juvenile idiopathic arthritis (JIA) is unique among the rheumatic diseases of childhood, given its distinctive systemic inflammatory character. Inappropriate control of innate immune responses following an initially harmless trigger is thought to account for the excessive inflammatory reaction. The aim of this study was to generate a similar systemic inflammatory syndrome in mice by injecting a relatively innocuous, yet persistent, immune system trigger: Freund's complete adjuvant (CFA), containing heat-killed mycobacteria.

+ View Abstract

Arthritis & rheumatology (Hoboken, N.J.), 66, 2326-5205, , 2014

PMID:24470407

Open Access

Mast cells play no role in the pathogenesis of postoperative ileus induced by intestinal manipulation.
Gomez-Pinilla PJ, Farro G, Di Giovangiulio M, Stakenborg N, Némethova A, de Vries A, Liston A, Feyerabend TB, Rodewald HR, Rodewald HR, Boeckxstaens GE, Matteoli G

Intestinal manipulation (IM) during abdominal surgery results in intestinal inflammation leading to hypomotility or ileus. Mast cell activation is thought to play a crucial role in the pathophysiology of postoperative ileus (POI). However, this conclusion was mainly drawn using mast cell-deficient mouse models with abnormal Kit signaling. These mice also lack interstitial cells of Cajal (ICC) resulting in aberrant gastrointestinal motility even prior to surgery, compromising their use as model to study POI. To avoid these experimental weaknesses we took advantage of a newly developed knock-in mouse model, Cpa3(Cre/+) , devoid of mast cells but with intact Kit signaling.

+ View Abstract

PloS one, 9, 1932-6203, , 2014

PMID:24416383

Open Access

Beta-2 microglobulin is important for disease progression in a murine model for amyotrophic lateral sclerosis.
Staats KA, Schönefeldt S, Van Rillaer M, Van Hoecke A, Van Damme P, Robberecht W, Liston A, Van Den Bosch L

Beta-2 microglobulin (β2m) is an essential component of the major histocompatibility complex (MHC) class I proteins and in the nervous system β2m is predominantly expressed in motor neurons. As β2m can promote nerve regeneration, we investigated its potential role in amyotrophic lateral sclerosis (ALS) by investigating its expression level as well as the effect of genetically removing β2m on the disease process in mutant superoxide dismutase 1 (SOD1 (G93A) ) mice, a model of ALS. We observed a strong upregulation of β2m in motor neurons during the disease process and ubiquitous removal of β2m dramatically shortens the disease duration indicating that β2m plays an essential and positive role during the disease process. We hypothesize that β2m contributes to plasticity that is essential for muscle reinnervation. Absence of this plasticity will lead to faster muscle denervation and counteracting this process could be a relevant therapeutic target.

+ View Abstract

Frontiers in cellular neuroscience, 7, 1662-5102, , 2013

PMID:24368896

Open Access

A ZAP-70 kinase domain variant prevents thymocyte-positive selection despite signalling CD69 induction.
Siggs OM, Yates AL, Schlenner S, Liston A, Lesage S, Goodnow CC

Quantitative reductions in T-cell receptor (TCR) signalling are associated with severe immunodeficiency, yet in certain cases can lead to autoimmunity. Mutation of the tyrosine kinase ZAP-70 can cause either of these outcomes, yet the limits of its signal transducing capacity are not well defined. To investigate these limits we have made use of mrtless: a chemically induced mutation of Zap70 associated with T-cell deficiency. Unlike cells devoid of ZAP-70, mrtless thymocytes showed partial induction of CD5 and CD69, and were sensitive to TCR stimulation with a dose-response shifted approximately 10-fold. However, essentially no T cells were able to compensate for the mrtless mutation and mature beyond the CD4⁺ CD8⁺ stage. This outcome contrasts with a ZAP-70 Src Homology 2 domain mutant strain, where high-affinity self-reactive TCR are positively selected rather than deleted. We discuss these data with respect to current models of TCR signalling in thymocyte selection.

+ View Abstract

Immunology, 141, 1365-2567, , 2014

PMID:24266404

Open Access

IL-2 coordinates IL-2-producing and regulatory T cell interplay.
Amado IF, Berges J, Luther RJ, Mailhé MP, Garcia S, Bandeira A, Weaver C, Liston A, Freitas AA

Many species of bacteria use quorum sensing to sense the amount of secreted metabolites and to adapt their growth according to their population density. We asked whether similar mechanisms would operate in lymphocyte homeostasis. We investigated the regulation of the size of interleukin-2 (IL-2)-producing CD4(+) T cell (IL-2p) pool using different IL-2 reporter mice. We found that in the absence of either IL-2 or regulatory CD4(+) T (T reg) cells, the number of IL-2p cells increases. Administration of IL-2 decreases the number of cells of the IL-2p cell subset and, pertinently, abrogates their ability to produce IL-2 upon in vivo cognate stimulation, while increasing T reg cell numbers. We propose that control of the IL-2p cell numbers occurs via a quorum sensing-like feedback loop where the produced IL-2 is sensed by both the activated CD4(+) T cell pool and by T reg cells, which reciprocally regulate cells of the IL-2p cell subset. In conclusion, IL-2 acts as a self-regulatory circuit integrating the homeostasis of activated and T reg cells as CD4(+) T cells restrain their growth by monitoring IL-2 levels, thereby preventing uncontrolled responses and autoimmunity.

+ View Abstract

The Journal of experimental medicine, 210, 1540-9538, , 2013

PMID:24249704

Open Access

A novel Zap70 mutation with reduced protein stability demonstrates the rate-limiting threshold for Zap70 in T-cell receptor signalling.
Cauwe B, Tian L, Franckaert D, Pierson W, Staats KA, Schlenner SM, Liston A

Loss of ζ-associated protein 70 (Zap70) results in severe immunodeficiency in humans and mice because of the critical role of Zap70 in T-cell receptor (TCR) signalling. Here we describe a novel mouse strain generated by N-ethyl-N-nitrosourea mutagenesis, with the reduced protein stability (rps) mutation in Zap70. The A243V rps mutation resulted in decreased Zap70 protein and a reduced duration of TCR-induced calcium responses, equivalent to that induced by a 50% decrease in catalytically active Zap70. The reduction of signalling through Zap70 was insufficient to substantially perturb thymic differentiation of conventional CD4 and CD8 T cells, although Foxp3(+) regulatory T cells demonstrated altered thymic production and peripheral homeostasis. Despite the mild phenotype, the Zap70(A243V) variant lies just above the functional threshold for TCR signalling competence, as T cells relying on only a single copy of the Zap70(rps) allele for TCR signalling demonstrated no intracellular calcium response to TCR stimulation. This addition to the Zap70 allelic series indicates that a rate-limiting threshold for Zap70 protein levels exists at which signalling capacity switches from nearly intact to effectively null.

+ View Abstract

Immunology, 141, 1365-2567, , 2014

PMID:24164480

Open Access

The intracellular sensor NOD2 induces microRNA-29 expression in human dendritic cells to limit IL-23 release.
Brain O, Owens BM, Pichulik T, Allan P, Khatamzas E, Leslie A, Steevels T, Sharma S, Mayer A, Catuneanu AM, Morton V, Sun MY, Jewell D, Coccia M, Harrison O, Maloy K, Schönefeldt S, Bornschein S, Liston A, Simmons A

NOD2 is an intracellular sensor that contributes to immune defense and inflammation. Here we investigated whether NOD2 mediates its effects through control of microRNAs (miRNAs). miR-29 expression was upregulated in human dendritic cells (DCs) in response to NOD2 signals, and miR-29 regulated the expression of multiple immune mediators. In particular, miR-29 downregulated interleukin-23 (IL-23) by targeting IL-12p40 directly and IL-23p19 indirectly, likely via reduction of ATF2. DSS-induced colitis was worse in miR-29-deficient mice and was associated with elevated IL-23 and T helper 17 signature cytokines in the intestinal mucosa. Crohn's disease (CD) patient DCs expressing NOD2 polymorphisms failed to induce miR-29 upon pattern recognition receptor stimulation and showed enhanced release of IL-12p40 on exposure to adherent invasive E. coli. Therefore, we suggest that loss of miR-29-mediated immunoregulation in CD DCs might contribute to elevated IL-23 in this disease.

+ View Abstract

Immunity, 39, 1097-4180, , 2013

PMID:24054330

Open Access

Rapamycin increases survival in ALS mice lacking mature lymphocytes.
Staats KA, Hernandez S, Schönefeldt S, Bento-Abreu A, Dooley J, Van Damme P, Liston A, Robberecht W, Van Den Bosch L

Amyotrophic Lateral Sclerosis (ALS) is a devastating progressive neurodegenerative disease. Disease pathophysiology is complex and not yet fully understood, but is proposed to include the accumulation of misfolded proteins, as aggregates are present in spinal cords from ALS patients and in ALS model organisms. Increasing autophagy is hypothesized to be protective in ALS as it removes these aggregates. Rapamycin is frequently used to increase autophagy, but is also a potent immune suppressor. To properly assess the role of rapamycin-induced autophagy, the immune suppressive role of rapamycin should be negated.

+ View Abstract

Molecular neurodegeneration, 8, 1750-1326, , 2013

PMID:24025516

Open Access

Genetic ablation of phospholipase C delta 1 increases survival in SOD1(G93A) mice.
Staats KA, Van Helleputte L, Jones AR, Bento-Abreu A, Van Hoecke A, Shatunov A, Simpson CL, Lemmens R, Jaspers T, Fukami K, Nakamura Y, Brown RH, Van Damme P, Liston A, Robberecht W, Al-Chalabi A, Van Den Bosch L

Amyotrophic Lateral Sclerosis (ALS) is a devastating progressive neurodegenerative disease, resulting in selective motor neuron degeneration and paralysis. Patients die approximately 3-5 years after diagnosis. Disease pathophysiology is multifactorial, including excitotoxicity, but is not yet fully understood. Genetic analysis has proven fruitful in the past to further understand genes modulating the disease and increase knowledge of disease mechanisms. Here, we revisit a previously performed microsatellite analysis in ALS and focus on another hit, PLCD1, encoding phospholipase C delta 1 (PLCδ1), to investigate its role in ALS. PLCδ1 may contribute to excitotoxicity as it increases inositol 1,4,5-trisphosphate (IP3) formation, which releases calcium from the endoplasmic reticulum through IP3 receptors. We find that expression of PLCδ1 is increased in ALS mouse spinal cord and in neurons from ALS mice. Furthermore, genetic ablation of this protein in ALS mice significantly increases survival, but does not affect astrogliosis, microgliosis, aggregation or the amount of motor neurons at end stage compared to ALS mice with PLCδ1. Interestingly, genetic ablation of PLCδ1 prevents nuclear shrinkage of motor neurons in ALS mice at end stage. These results indicate that PLCD1 contributes to ALS and that PLCδ1 may be a new target for future studies.

+ View Abstract

Neurobiology of disease, 60, 1095-953X, , 2013

PMID:23969236

Developmental plasticity of murine and human Foxp3(+) regulatory T cells.
Liston A, Piccirillo CA

Murine and human CD4(+) regulatory T (Treg) cells expressing the Forkhead box p3 (Foxp3) transcription factor represent a distinct, highly differentiated CD4(+) T cell lineage that is programmed for dominant self-tolerance and control of immune responses against a variety of foreign antigens. Sustained Foxp3 expression in these cells drives the differentiation of a regulatory phenotype and ensures the stability of their suppressive functions under a variety of inflammatory settings. Some recent studies have challenged this premise and advanced the notion that Foxp3(+) Treg cells manifest a high degree of functional plasticity that enables them to adapt and reprogram into effector-like T cells in response to various inflammatory stimuli. The concept of Treg cell plasticity remains highly contentious, with a high degree of variation in measured plasticity potential observed under different experimental conditions. In this chapter, we propose a unifying model of Treg cell plasticity, which hypothesizes that the stable fates of regulatory and effector T (Teff) cell lineages allow transient plasticity into the alternative lineage under a discrete set of microenvironmental influences associated with, respectively, the initiation and resolution phases of infection. This model utilizes a theoretical framework consistent with the requirements for effective immune regulation and accounts for both the extraordinary long-term stability of Treg cells and the observed fate plasticity.

+ View Abstract

Advances in immunology, 119, 1557-8445, , 2013

PMID:23886065

Antiapoptotic Mcl-1 is critical for the survival and niche-filling capacity of Foxp3⁺ regulatory T cells.
Pierson W, Cauwe B, Policheni A, Schlenner SM, Franckaert D, Berges J, Humblet-Baron S, Schönefeldt S, Herold MJ, Hildeman D, Strasser A, Bouillet P, Lu LF, Matthys P, Freitas AA, Luther RJ, Weaver CT, Dooley J, Gray DH, Liston A

Foxp3⁺ regulatory T (Treg) cells are a crucial immunosuppressive population of CD4⁺ T cells, yet the homeostatic processes and survival programs that maintain the Treg cell pool are poorly understood. Here we report that peripheral Treg cells markedly alter their proliferative and apoptotic rates to rapidly restore numerical deficit through an interleukin 2-dependent and costimulation-dependent process. By contrast, excess Treg cells are removed by attrition, dependent on the Bim-initiated Bak- and Bax-dependent intrinsic apoptotic pathway. The antiapoptotic proteins Bcl-xL and Bcl-2 were dispensable for survival of Treg cells, whereas Mcl-1 was critical for survival of Treg cells, and the loss of this antiapoptotic protein caused fatal autoimmunity. Together, these data define the active processes by which Treg cells maintain homeostasis via critical survival pathways.

+ View Abstract

Nature immunology, 14, 1529-2916, , 2013

PMID:23852275

Open Access

Olmsted syndrome: exploration of the immunological phenotype.
Danso-Abeam D, Zhang J, Dooley J, Staats KA, Van Eyck L, Van Brussel T, Zaman S, Hauben E, Van de Velde M, Morren MA, Renard M, Van Geet C, Schaballie H, Lambrechts D, Tao J, Franckaert D, Humblet-Baron S, Meyts I, Liston A

Olmsted syndrome is a rare congenital skin disorder presenting with periorifical hyperkeratotic lesions and mutilating palmoplantar keratoderma, which is often associated with infections of the keratotic area. A recent study identified de novo mutations causing constitutive activation of TRPV3 as a cause of the keratotic manifestations of Olmsted syndrome.

+ View Abstract

Orphanet journal of rare diseases, 8, 1750-1172, , 2013

PMID:23692804

Open Access

An evolutionarily conserved mutual interdependence between Aire and microRNAs in promiscuous gene expression.
Ucar O, Tykocinski LO, Dooley J, Liston A, Kyewski B

The establishment and maintenance of central tolerance depends to a large extent on the ability of medullary thymic epithelial cells to express a variety of tissue-restricted antigens, the so-called promiscuous gene [removed]pGE). Autoimmune regulator (Aire) is to date the best characterised transcriptional regulator known to at least partially coordinate pGE. There is accruing evidence that the expression of Aire-dependent and -independent genes is modulated by higher order chromatin configuration, epigenetic modifications and post-transcriptional control. Given the involvement of microRNAs (miRNAs) as potent post-transcriptional modulators of gene expression, we investigated their role in the regulation of pGE in purified mouse and human thymic epithelial cells (TECs). Microarray profiling of TEC subpopulations revealed evolutionarily conserved cell type and differentiation-specific miRNA signatures with a subset of miRNAs being significantly upregulated during terminal medullary thymic epithelial cell differentiation. The differential regulation of this subset of miRNAs was correlated with Aire expression and some of these miRNAs were misexpressed in the Aire knockout thymus. In turn, the specific absence of miRNAs in TECs resulted in a progressive reduction of Aire expression and pGE, affecting both Aire-dependent and -independent genes. In contrast, the absence of miR-29a only affected the Aire-dependent gene pool. These findings reveal a mutual interdependence of miRNA and Aire.

+ View Abstract

European journal of immunology, 43, 1521-4141, , 2013

PMID:23589212

Open Access

MicroRNA regulation of T-cell development.
Dooley J, Linterman MA, Liston A

MicroRNAs are short, 19-24 nucleotide long, RNA molecules capable of regulating the longevity and, to a lesser extent, translation of messenger RNA (mRNA) species. The function of the microRNA network, and indeed, even that of individual microRNA species, can have profoundly different roles in even a single cell type as the microRNA/mRNA composition evolves. As the role of microRNA within T cells has come under increasing scrutiny, several distinct checkpoints have been demonstrated to have a particular reliance on microRNA regulation. MicroRNAs are arguably most important in T cells during the earliest and last stages in T-cell biology. The first stages of early thymic differentiation have a crucial reliance on the microRNA network, while later stages and peripheral homeostasis are largely, although not completely, microRNA-independent. The most profound effects on T cells are in the activation of effector and regulatory functions of conventional and regulatory T cells, where microRNA deficiency results in a near-complete loss of function. In this review, we focus on integrating the research on individual microRNA into a more global understanding of the function of the microRNA regulatory network in T cells.

+ View Abstract

Immunological reviews, 253, 1600-065X, , 2013

PMID:23550638

No evidence for a role of rare CYP27B1 functional variations in multiple sclerosis.
Barizzone N, Pauwels I, Luciano B, Franckaert D, Guerini FR, Cosemans L, Hilven K, Salviati A, Dooley J, Danso-Abeam D, di Sapio A, Cavalla P, Decallonne B, Mathieu C, Liston A, Leone M, Dubois B, D'Alfonso S, Goris A

Association studies have implicated common variants in the 12q14.1 region containing CYP27B1 in multiple sclerosis (MS). Rare CYP27B1 mutations cause autosomal recessive vitamin D-dependent rickets type 1, and it has recently been reported that heterozygous CYP27B1 mutations are associated with increased MS susceptibility and lower active vitamin D levels. By sequencing CYP27B1 in 134 multiplex families and genotyping the most common variant R389H in 2,608 MS patients and 1,987 controls from Italy and Belgium (a total of 4,729 individuals), we were unable to replicate these observations. These results provide evidence against a major role for CYP27B1 mutations in MS.

+ View Abstract

Annals of neurology, 73, 1531-8249, , 2013

PMID:23483640

Inflammation-associated enterotypes, host genotype, cage and inter-individual effects drive gut microbiota variation in common laboratory mice.
Hildebrand F, Nguyen TL, Brinkman B, Yunta RG, Cauwe B, Vandenabeele P, Liston A, Raes J

Murine models are a crucial component of gut microbiome research. Unfortunately, a multitude of genetic backgrounds and experimental setups, together with inter-individual variation, complicates cross-study comparisons and a global understanding of the mouse microbiota landscape. Here, we investigate the variability of the healthy mouse microbiota of five common lab mouse strains using 16S rDNA pyrosequencing.

+ View Abstract

Genome biology, 14, 1474-760X, , 2013

PMID:23347395

Open Access

Antigen recognition by autoreactive CD4⁺ thymocytes drives homeostasis of the thymic medulla.
Irla M, Guerri L, Guenot J, Sergé A, Lantz O, Liston A, Imhof BA, Palmer E, Reith W

The thymic medulla is dedicated for purging the T-cell receptor (TCR) repertoire of self-reactive specificities. Medullary thymic epithelial cells (mTECs) play a pivotal role in this process because they express numerous peripheral tissue-restricted self-antigens. Although it is well known that medulla formation depends on the development of single-positive (SP) thymocytes, the mechanisms underlying this requirement are incompletely understood. We demonstrate here that conventional SP CD4⁺ thymocytes bearing autoreactive TCRs drive a homeostatic process that fine-tunes medullary plasticity in adult mice by governing the expansion and patterning of the medulla. This process exhibits strict dependence on TCR-reactivity with self-antigens expressed by mTECs, as well as engagement of the CD28-CD80/CD86 costimulatory axis. These interactions induce the expression of lymphotoxin α in autoreactive CD4⁺ thymocytes and RANK in mTECs. Lymphotoxin in turn drives mTEC development in synergy with RANKL and CD40L. Our results show that Ag-dependent interactions between autoreactive CD4⁺ thymocytes and mTECs fine-tune homeostasis of the medulla by completing the signaling axes implicated in mTEC expansion and medullary organization.

+ View Abstract

PloS one, 7, 1932-6203, , 2012

PMID:23300712

Open Access

Unusual selection and peripheral homeostasis for immunoregulatory CD4(-)  CD8(-) T cells.
Dugas V, Chabot-Roy G, Beauchamp C, Guimont-Desrochers F, Hillhouse EE, Liston A, Lesage S

Immunoregulatory CD4(-)  CD8(-) (double-negative; DN) T cells exhibit a unique antigen-specific mode of suppression, yet the ontogeny of DN T cells remains enigmatic. We have recently shown that 3A9 T-cell receptor (TCR) transgenic mice bear a high proportion of immunoregulatory 3A9 DN T cells, facilitating their study. The 3A9 TCR is positively selected on the H2(k) MHC haplotype, is negatively selected in mice bearing the cognate antigen, namely hen egg lysozyme, and there is absence of positive selection on the H2(b) MHC haplotype. Herein, we take advantage of this well-defined 3A9 TCR transgenic model to assess the thymic differentiation of DN T cells and its impact on determining the proportion of these cells in secondary lymphoid organs. We find that the proportion of DN T cells in the thymus is not dictated by the nature of the MHC-selecting haplotype. By defining DN T-cell differentiation in 3A9 TCR transgenic CD47-deficient mice as well as in mice bearing the NOD.H2(k) genetic background, we further demonstrate that the proportion of 3A9 DN T cells in the spleen is independent of the MHC selecting haplotype. Together, our findings suggest that immunoregulatory DN T cells are subject to rules distinct from those imposed upon CD4 T cells.

+ View Abstract

Immunology, 139, 1365-2567, , 2013

PMID:23293940

Open Access

Crucial role of transient receptor potential ankyrin 1 and mast cells in induction of nonallergic airway hyperreactivity in mice.
Hox V, Vanoirbeek JA, Alpizar YA, Voedisch S, Callebaut I, Bobic S, Sharify A, De Vooght V, Van Gerven L, Devos F, Liston A, Voets T, Vennekens R, Bullens DM, De Vries A, Hoet P, Braun A, Ceuppens JL, Talavera K, Nemery B, Hellings PW

Airway hyperreactivity (AHR) is a key feature of bronchial asthma, and inhalation of irritants may facilitate development of nonallergic AHR. Swimmers exposed to hypochlorite (ClO(-))-containing water show a higher risk of developing AHR. We developed a mouse model in which instillation of ClO(-) before ovalbumin (OVA) induces AHR without bronchial inflammatory cells.

+ View Abstract

American journal of respiratory and critical care medicine, 187, 1535-4970, , 2013

PMID:23262517

Aire mediates thymic expression and tolerance of pancreatic antigens via an unconventional transcriptional mechanism.
Danso-Abeam D, Staats KA, Franckaert D, Van Den Bosch L, Liston A, Gray DH, Dooley J

The autoimmune regulator (Aire), mediates central tolerance of peripheral self. Its activity in thymic epithelial cells (TECs) directs the ectopic expression of thousands of tissue-restricted antigens (TRAs), causing the deletion of autoreactive thymocytes. The molecular mechanisms orchestrating the breadth of transcriptional regulation by Aire remain unknown. One prominent model capable of explaining both the uniquely high number of Aire-dependent targets and their specificity posits that tissue-specific transcription factors induced by Aire directly activate their canonical targets, exponentially adding to the total number of Aire-dependent TRAs. To test this "Hierarchical Transcription" model, we analysed mice deficient in the pancreatic master transcription factor pancreatic and duodenal homeobox 1 (Pdx1), specifically in TECs (Pdx1(ΔFoxn1) ), for the expression and tolerance of pancreatic TRAs. Surprisingly, we found that lack of Pdx1 in TECs did not reduce the transcription of insulin or somatostatin, or alter glucagon expression. Moreover, in a model of thymic deletion driven by a neo-TRA under the control of the insulin promoter, Pdx1 in TECs was not required to affect thymocyte deletion or the generation of regulatory T (Treg) cells. These findings suggest that the capacity of Aire to regulate expression of a huge array of TRAs relies solely on an unconventional transcriptional mechanism, without intermediary transcription factors.

+ View Abstract

European journal of immunology, 43, 1521-4141, , 2013

PMID:23041971

Open Access

The thymic niche does not limit development of the naturally diverse population of mouse regulatory T lymphocytes.
Romagnoli P, Dooley J, Enault G, Vicente R, Malissen B, Liston A, van Meerwijk JP

Thymus-derived CD4(+)Foxp3(+) regulatory T lymphocytes (Tregs) play a central role in the suppression of immune responses to self-antigens and thus avoid autoimmune disorders. It remains unclear if the specialized thymic niche controls the number of differentiating Tregs. We investigated development of murine Tregs from precursors expressing the naturally very large repertoire of TCRs. By analyzing their developmental kinetics, we observed that differentiating Tregs dwell in the thymus ∼1 d longer than their conventional T cell counterparts. By generating hematopoietic chimeras with very low proportions of trackable precursors, we could follow individual waves of developing T cells in the thymus. We observed strongly increased proportions of Tregs at the end of the waves, confirming that these cells are the last to leave the thymus. To assess whether the thymic niche limits Treg development, we generated hematopoietic chimeras in which very few T cell precursors could develop. The substantial increase in the proportion of Tregs we found in these mice suggested a limiting role of the thymic niche; however, this increase was accounted for entirely by the prolonged thymic dwell time of Tregs. We conclude that, when precursors express a naturally diverse TCR repertoire, the thymic niche does not limit differentiation of Tregs.

+ View Abstract

Journal of immunology (Baltimore, Md. : 1950), 189, 1550-6606, , 2012

PMID:22988035

Open Access

MicroRNAs control the maintenance of thymic epithelia and their competence for T lineage commitment and thymocyte selection.
Zuklys S, Mayer CE, Zhanybekova S, Stefanski HE, Nusspaumer G, Gill J, Barthlott T, Chappaz S, Nitta T, Dooley J, Nogales-Cadenas R, Takahama Y, Finke D, Liston A, Blazar BR, Pascual-Montano A, Holländer GA

Thymic epithelial cells provide unique cues for the lifelong selection and differentiation of a repertoire of functionally diverse T cells. Rendered microRNA (miRNA) deficient, these stromal cells in the mouse lose their capacity to instruct the commitment of hematopoietic precursors to a T cell fate, to effect thymocyte positive selection, and to achieve promiscuous gene expression required for central tolerance induction. Over time, the microenvironment created by miRNA-deficient thymic epithelia assumes the cellular composition and structure of peripheral lymphoid tissue, where thympoiesis fails to be supported. These findings emphasize a global role for miRNA in the maintenance and function of the thymic epithelial cell scaffold and establish a novel mechanism how these cells control peripheral tissue Ag expression to prompt central immunological tolerance.

+ View Abstract

Journal of immunology (Baltimore, Md. : 1950), 189, 1550-6606, , 2012

PMID:22972926

Open Access

MicroRNA-29 in the adaptive immune system: setting the threshold.
Liston A, Papadopoulou AS, Danso-Abeam D, Dooley J

Recent research into the role of microRNA (miR) in the immune system has identified the miR-29 family as critical regulators of key processes in adaptive immunity. The miR-29 family consists of four members with shared regulatory capacity, namely miR-29a, miR-29b-1, miR-29b-2 and miR-29c. Being expressed in both T and B cells, as well as the main accessory cell types of thymic epithelium and dendritic cells, the miR-29 family has been identified as a putative regulator of immunity due to the predicted suppression of key immunological pathways. The generation of a series of in vivo molecular tools targeting the miR-29 family has identified the critical role of these miR in setting the molecular threshold for three central events in adaptive immunity: (1) control over thymic production of T cells by modulating the threshold for infection-associated thymic involution, (2) creating a neutral threshold for T cell polarization following activation, and (3) setting the threshold for B cell oncogenic transformation. These results identify the miR-29 family as potent immune modulators which have already been exploited through the evolution of a viral mimic and could potentially be exploited further for therapeutic intervention.

+ View Abstract

Cellular and molecular life sciences : CMLS, 69, 1420-9071, , 2012

PMID:22971773

Models of aire-dependent gene regulation for thymic negative selection.
Danso-Abeam D, Humblet-Baron S, Dooley J, Liston A

Mutations in the autoimmune regulator (AIRE) gene lead to autoimmune polyendocrinopathy syndrome type 1 (APS1), characterized by the development of multi-organ autoimmune damage. The mechanism by which defects in AIRE result in autoimmunity has been the subject of intense scrutiny. At the cellular level, the working model explains most of the clinical and immunological characteristics of APS1, with AIRE driving the expression of tissue-restricted antigens (TRAs) in the epithelial cells of the thymic medulla. This TRA expression results in effective negative selection of TRA-reactive thymocytes, preventing autoimmune disease. At the molecular level, the mechanism by which AIRE initiates TRA expression in the thymic medulla remains unclear. Multiple different models for the molecular mechanism have been proposed, ranging from classical transcriptional activity, to random induction of gene expression, to epigenetic tag recognition effect, to altered cell biology. In this review, we evaluate each of these models and discuss their relative strengths and weaknesses.

+ View Abstract

Frontiers in immunology, 2, 1664-3224, , 2011

PMID:22566805

Open Access

Molecular control over thymic involution: from cytokines and microRNA to aging and adipose tissue.
Dooley J, Liston A

The thymus is the primary organ for T-cell differentiation and maturation. Unlike other major organs, the thymus is highly dynamic, capable of undergoing multiple rounds of almost complete atrophy followed by rapid restoration. The process of thymic atrophy, or involution, results in decreased thymopoiesis and emigration of naïve T cells to the periphery. Multiple processes can trigger transient thymic involution, including bacterial and viral infection(s), aging, pregnancy and stress. Intense investigations into the mechanisms that underlie thymic involution have revealed diverse cellular and molecular mediators, with elaborate control mechanisms. This review outlines the disparate pathways through which involution can be mediated, from the transient infection-mediated pathway, tightly controlled by microRNA, to the chronic changes that occur through aging.

+ View Abstract

European journal of immunology, 42, 1521-4141, , 2012

PMID:22539280

Open Access

T-follicular helper cell differentiation and the co-option of this pathway by non-helper cells.
Linterman MA, Liston A, Vinuesa CG

Human and mouse studies performed over the last decade have established that follicular helper T (Tfh) cells are a CD4(+) helper subset specialized in the provision of help to B cells. Tfh differentiation is driven by expression of the transcriptional repressor B-cell lymphoma-6 (Bcl-6), which turns on a program that guides T cells close to B-cell areas where Tfh cells first provide help to B cells. Sustained Bcl-6 expression promotes the entry of Tfh cells into follicles and modulates their cytokine expression profile so they can support and select germinal center B cells that have acquired affinity-enhancing mutations in their immunoglobulin genes. Forkhead box 3 protein (Foxp3)(+) regulatory T cells and invariant natural killer T (NKT) cells can also co-opt the Bcl-6-dependent follicular differentiation pathway to migrate into B-cell follicles and regulate antibody responses. The resulting NKT follicular helper cells drive a distinctive type of T-dependent B-cell response to lipid-containing antigens, whereas FoxP3(+) follicular regulatory (Tfr) cells exert a suppressive function on germinal centers. Elucidating how Tfr cells are functionally and numerically regulated and the factors that control the balance between Tfh and Tfr cells is likely to be critical for improved understanding of the pathogenesis and progression of autoimmunity and lymphomas of germinal center origin, and generation of effective vaccines.

+ View Abstract

Immunological reviews, 247, 1600-065X, , 2012

PMID:22500838

Immune tolerance: are regulatory T cell subsets needed to explain suppression of autoimmunity?
Tian L, Humblet-Baron S, Liston A

The potential for self-reactive T cells to cause autoimmune disease is held in check by Foxp3(+) regulatory T cells (Tregs), essential mediators of peripheral immunological tolerance. Tregs have the capacity to suppress multiple branches of the immune system, tightly controlling the different subsets of effector T cells across multiple different tissue environments. Recent genetic experiments have found mutations that disrupt specific Treg: effector T cell relationships, leading to the possibility that subsets of Tregs are required to suppress each subset of effector T cells. Here we review the environmental factors and mechanisms that allow Tregs to suppress specific subsets of effector T cells, and find that a parsimonious explanation of the genetic data can be made without invoking Treg subsets. Instead, Tregs show a functional and chemotactic plasticity based on microenvironmental influences that allows the common pool of cells to suppress multiple distinct immune responses.

+ View Abstract

BioEssays : news and reviews in molecular, cellular and developmental biology, 34, 1521-1878, , 2012

PMID:22419393

The immunogenetic architecture of autoimmune disease.
Goris A, Liston A

The development of most autoimmune diseases includes a strong heritable component. This genetic contribution to disease ranges from simple Mendelian inheritance of causative alleles to the complex interactions of multiple weak loci influencing risk. The genetic variants responsible for disease are being discovered through a range of strategies from linkage studies to genome-wide association studies. Despite the rapid advances in genetic analysis, substantial components of the heritable risk remain unexplained, either owing to the contribution of an as-yet unidentified, "hidden," component of risk, or through the underappreciated effects of known risk loci. Surprisingly, despite the variation in genetic control, a great deal of conservation appears in the biological processes influenced by risk alleles, with several key immunological pathways being modified in autoimmune diseases covering a broad spectrum of clinical manifestations. The primary translational potential of this knowledge is in the rational design of new therapeutics to exploit the role of these key pathways in influencing disease. With significant further advances in understanding the genetic risk factors and their biological mechanisms, the possibility of genetically tailored (or "personalized") therapy may be realized.

+ View Abstract

Cold Spring Harbor perspectives in biology, 4, 1943-0264, , 2012

PMID:22383754

Open Access

Macrophages have no lineage history of Foxp3 expression.
Put S, Avau A, Humblet-Baron S, Schurgers E, Liston A, Matthys P

Blood, 119, 1528-0020, , 2012

PMID:22308283

Open Access

Loss of T cell microRNA provides systemic protection against autoimmune pathology in mice.
Tian L, De Hertogh G, Fedeli M, Staats KA, Schonefeldt S, Humblet-Baron S, Van Den Bosch L, Dellabona P, Dooley J, Liston A

With an increasing number of studies demonstrating alterations in T cell microRNA expression during autoimmune disease, modulation of the T cell microRNA network is considered a potential therapeutic strategy. Due to the complex and often opposing interactions of individual microRNA, prioritization of therapeutic targets first requires dissecting the dominant effects of the T cell microRNA network. Initial results utilizing a unidirectional screen suggested that the tolerogenic functions were dominant, with spontaneous colitis resulting from T cell-specific excision of Dicer. Here we performed a bidirectional screen for microRNA function by removing Dicer from the T cells of both wildtype mice and Transforming Growth Factor β (TGFβ) receptor-deficient mice. This allowed the impact of microRNA loss on T cell activation, effector T cell differentiation and autoimmune pathology to be systematically assessed. This bidirectional screen revealed a dominant immunogenic function for T cell microRNA, with potent suppression of T cell activation, IFNγ production and autoimmune pathology in all targeted organs except the colon, where Dicer-dependent microRNA demonstrated a dominant tolerogenic function. These results reverse the original conclusions of microRNA function in T cells by revealing a systemic pro-autoimmune function.

+ View Abstract

Journal of autoimmunity, 38, 1095-9157, , 2012

PMID:22225602

Open Access

The thymic epithelial microRNA network elevates the threshold for infection-associated thymic involution via miR-29a mediated suppression of the IFN-α receptor.
Papadopoulou AS, Dooley J, Linterman MA, Pierson W, Ucar O, Kyewski B, Zuklys S, Hollander GA, Matthys P, Gray DH, De Strooper B, Liston A

Thymic output is a dynamic process, with high activity at birth punctuated by transient periods of involution during infection. Interferon-α (IFN-α) is a critical molecular mediator of pathogen-induced thymic involution, yet despite the importance of thymic involution, relatively little is known about the molecular integrators that establish sensitivity. Here we found that the microRNA network dependent on the endoribonuclease Dicer, and specifically microRNA miR-29a, was critical for diminishing the sensitivity of the thymic epithelium to simulated infection signals, protecting the thymus against inappropriate involution. In the absence of Dicer or the miR-29a cluster in the thymic epithelium, expression of the IFN-α receptor by the thymic epithelium was higher, which allowed suboptimal signals to trigger rapid loss of thymic cellularity.

+ View Abstract

Nature immunology, 13, 1529-2916, , 2012

PMID:22179202

Open Access

Foxp3+ follicular regulatory T cells control the germinal center response.
Linterman MA, Pierson W, Lee SK, Kallies A, Kawamoto S, Rayner TF, Srivastava M, Divekar DP, Beaton L, Hogan JJ, Fagarasan S, Liston A, Smith KG, Vinuesa CG

Follicular helper (T(FH)) cells provide crucial signals to germinal center B cells undergoing somatic hypermutation and selection that results in affinity maturation. Tight control of T(FH) numbers maintains self tolerance. We describe a population of Foxp3(+)Blimp-1(+)CD4(+) T cells constituting 10-25% of the CXCR5(high)PD-1(high)CD4(+) T cells found in the germinal center after immunization with protein antigens. These follicular regulatory T (T(FR)) cells share phenotypic characteristics with T(FH) and conventional Foxp3(+) regulatory T (T(reg)) cells yet are distinct from both. Similar to T(FH) cells, T(FR) cell development depends on Bcl-6, SLAM-associated protein (SAP), CD28 and B cells; however, T(FR) cells originate from thymic-derived Foxp3(+) precursors, not naive or T(FH) cells. T(FR) cells are suppressive in vitro and limit T(FH) cell and germinal center B cell numbers in vivo. In the absence of T(FR) cells, an outgrowth of non-antigen-specific B cells in germinal centers leads to fewer antigen-specific cells. Thus, the T(FH) differentiation pathway is co-opted by T(reg) cells to control the germinal center response.

+ View Abstract

Nature medicine, 17, 1546-170X, , 2011

PMID:21785433

Open Access

Foxp3⁺ regulatory T cells exert asymmetric control over murine helper responses by inducing Th2 cell apoptosis.
Tian L, Altin JA, Makaroff LE, Franckaert D, Cook MC, Goodnow CC, Dooley J, Liston A

Foxp3(+) regulatory T cells play a pivotal role in maintaining self-tolerance and immune homeostasis. In the absence of regulatory T cells, generalized immune activation and multiorgan T cell-driven pathology occurs. Although the phenomenon of immunologic control by Foxp3(+) regulatory T cells is well recognized, the comparative effect over different arms of the immune system has not been thoroughly investigated. Here, we generated a cohort of mice with a continuum of regulatory T-cell frequencies ranging from physiologic levels to complete deficiency. This titration of regulatory T-cell depletion was used to determine how different effector subsets are controlled. We found that in vivo Foxp3(+) regulatory T-cell frequency had a proportionate relationship with generalized T-cell activation and Th1 magnitude, but it had a surprising disproportionate relationship with Th2 magnitude. The asymmetric regulation was associated with efficient suppression of Th2 cells through additional regulations on the apoptosis rate in Th2 cells and not Th1 cells and could be replicated by CTLA4-Ig or anti-IL-2 Ab. These results indicate that the Th2 arm of the immune system is under tighter control by regulatory T cells than the Th1 arm, suggesting that Th2-driven diseases may be more responsive to regulatory T-cell manipulation.

+ View Abstract

Blood, 118, 1528-0020, , 2011

PMID:21715314

Open Access

Regulatory T cells fulfil their promise?
Humblet-Baron S, Baron F, Liston A

Immunology and cell biology, 89, 1440-1711, , 2011

PMID:21606944

Open Access

Aire regulates the transfer of antigen from mTECs to dendritic cells for induction of thymic tolerance.
Hubert FX, Kinkel SA, Davey GM, Phipson B, Mueller SN, Liston A, Proietto AI, Cannon PZ, Forehan S, Smyth GK, Wu L, Goodnow CC, Carbone FR, Scott HS, Heath WR

To investigate the role of Aire in thymic selection, we examined the cellular requirements for generation of ovalbumin (OVA)-specific CD4 and CD8 T cells in mice expressing OVA under the control of the rat insulin promoter. Aire deficiency reduced the number of mature single-positive OVA-specific CD4(+) or CD8(+) T cells in the thymus, independent of OVA expression. Importantly, it also contributed in 2 ways to OVA-dependent negative selection depending on the T-cell type. Aire-dependent negative selection of OVA-specific CD8 T cells correlated with Aire-regulated expression of OVA. By contrast, for OVA-specific CD4 T cells, Aire affected tolerance induction by a mechanism that operated independent of the level of OVA expression, controlling access of antigen presenting cells to medullary thymic epithelial cell (mTEC)-expressed OVA. This study supports the view that one mechanism by which Aire controls thymic negative selection is by regulating the indirect presentation of mTEC-derived antigens by thymic dendritic cells. It also indicates that mTECs can mediate tolerance by direct presentation of Aire-regulated antigens to both CD4 and CD8 T cells.

+ View Abstract

Blood, 118, 1528-0020, , 2011

PMID:21505196

Open Access

Decreased T-cell receptor signaling through CARD11 differentially compromises forkhead box protein 3-positive regulatory versus T(H)2 effector cells to cause allergy.
Altin JA, Tian L, Liston A, Bertram EM, Goodnow CC, Cook MC

Allergy, the most common disease of immune dysregulation, has a substantial genetic component that is poorly understood. Although complete disruption of T-cell receptor (TCR) signaling causes profound immunodeficiency, little is known about the consequences of inherited genetic variants that cause partial quantitative decreases in particular TCR-signaling pathways, despite their potential to dysregulate immune responses and cause immunopathology.

+ View Abstract

The Journal of allergy and clinical immunology, 127, 1097-6825, , 2011

PMID:21320717

Open Access

Genetic tools for analysis of FoxP3+ regulatory T cells in vivo.
Jeremiah NM, Liston A

The discovery of Foxp3 as a reliable marker for murine regulatory T cells has led to an explosion in the development of genetic tools for investigating the biology of regulatory T cells. More than 25 Foxp3-based mouse strains have been published with a variety of characteristics. The effects of Foxp3 expression can be analyzed using null, hypomorphic, conditional, altered control, and over-expression strains. Reporter strains are available to efficiently isolate Foxp3+ cells, with various reporter designs in terms of construct (fusion, replacement, and bicistronic positioning), and reporter system &#40;GFP, YFP, RFP, Luciferase, Thy1.1&#41;. Multifunction strain fusion, replacement, and bicistronic positionings add functional proteins under the control of the Foxp3 promoter allowing induced apoptosis or lineage-specific Cre recombinase activity. In this chapter, we discuss the uses of the cornucopia of genetic tools, in isolation and in combination, for research on Foxp3(+) regulatory T cells.

+ View Abstract

Methods in molecular biology (Clifton, N.J.), 707, 1940-6029, , 2011

PMID:21287332

Immunological tolerance 50 years after the Burnet Nobel Prize.
Liston A

Immunology and cell biology, 89, 1440-1711, , 2011

PMID:21209621

Is foxp3 the master regulator of regulatory T cells?
Liston A

Progress in molecular biology and translational science, 92, 1877-1173, , 2010

PMID:20800826

The development of T-cell immunity.
Liston A

Progress in molecular biology and translational science, 92, 1877-1173, , 2010

PMID:20800810

A new role for interleukin-10 in immune regulation.
Pierson W, Liston A

Immunology and cell biology, 88, 1440-1711, , 0

PMID:20714338

Understanding the genetic regulation of IgE production.
Altin J, Shen C, Liston A

Immunoglobulin E (IgE) is a key mediator of anti-parasitic and anti-tumour immunity. However it is also a critical component of atopic and autoimmune diseases, and elevated serum IgE levels are a common indicator of immune dysregulation. In this review we survey the literature on genetic associations of elevated IgE in humans and mice. We find that defects in a limited number of pathways explain the majority of gene associations with IgE. Commonly, elevated IgE is associated with defects in Th bias and B cell class switching, severe T cell tolerance defects and defects in immunity at the host-environment interface. These genetic data demonstrate the mechanisms of control over IgE production and the manner in which they can be circumvented.

+ View Abstract

Blood reviews, 24, 1532-1681, , 0

PMID:20637535

MicroRNA in the adaptive immune system, in sickness and in health.
Liston A, Linterman M, Lu LF

MicroRNA are emerging as key regulators of the development and function of adaptive immunity. These 19-24 nucleotide regulatory RNA molecules have essential roles in multiple faucets of adaptive immunity, from regulating the development of the key cellular players to the activation and function in immune responses.

+ View Abstract

Journal of clinical immunology, 30, 1573-2592, , 2010

PMID:20191314

MicroRNA in the immune system, microRNA as an immune system.
Lu LF, Liston A

The advent of microRNA has potentially uncovered a new level of complexity to be considered for every biological process. Through the modulation of transcription and translation, microRNA alter the basal state of cells and the outcome of stimulatory events. The exact effect of the microRNA network and individual microRNA on cellular processes is only just starting to be dissected. In the immune system, microRNA appear to have a key role in the early differentiation and effector differentiation of B cells. In T cells, microRNA have been shown to be key regulators of the lineage induction pathways, and to have a strong role in the induction, function and maintenance of the regulatory T-cell lineage. MicroRNA are also important for regulating the differentiation of dendritic cells and macrophages via toll-like receptors, with responsibilities in suppressing effector function before activation and enhancing function after stimulation. In addition to regulating key processes in the immune system, microRNA may also represent an archaic immune system themselves. Small interfering RNA of viral origin has been shown to function as an intracellular mediator in the suppression of viral infection in eukaryotes as diverse as plants, insects, nematodes and fungi, and there is growing evidence that endogenous mammalian microRNA can have similar impacts. In this article we speculate that the anti-viral function of microRNA drove the expression of different subsets of microRNA in different cellular lineages, which may have, in turn, led to the myriad of roles microRNA play in lineage differentiation and stability.

+ View Abstract

Immunology, 127, 1365-2567, , 2009

PMID:19538248

Open Access

Short-circuiting regulatory T-cell proliferation during chronic infection.
Liston A, Kim JM

Immunology and cell biology, 87, 1440-1711, , 0

PMID:19399027

Inhibition of CCR6 function reduces the severity of experimental autoimmune encephalomyelitis via effects on the priming phase of the immune response.
Liston A, Kohler RE, Townley S, Haylock-Jacobs S, Comerford I, Caon AC, Webster J, Harrison JM, Swann J, Clark-Lewis I, Korner H, McColl SR

Chemokines are essential for homeostasis and activation of the immune system. The chemokine ligand/receptor pairing CCL20/CCR6 is interesting because these molecules display characteristics of both homeostatic and activation functions. These dual characteristics suggest a role for CCR6 in the priming and effector phases of the immune response. However, while CCR6 has been implicated in the effector phase in several models, a role in the priming phase is less clear. Herein we analyze the role of CCR6 in these two important arms of the immune response during experimental autoimmune encephalomyelitis (EAE). Both CCR6 and its chemokine ligand CCL20 were up-regulated in the draining lymph nodes and spinal cord during EAE, and CCR6 was up-regulated on CD4(+) T cells that had divided following induction of EAE. The functional role of this expression was demonstrated by impaired development of EAE in gene-targeted CCR6-deficient mice and in mice treated either with a neutralizing anti-CCR6 Ab or with a novel receptor antagonist. Inhibition of EAE was due to reduced priming of autoreactive CD4(+) T cells probably as a result of impaired late-stage influx of dendritic cells into draining lymph nodes. This was accompanied by reduced egress of activated lymphocytes from the lymph nodes. These results demonstrate a novel role for CCR6 in the mechanism of autoreactive lymphocyte priming and emigration to the efferent lymphatics.

+ View Abstract

Journal of immunology (Baltimore, Md. : 1950), 182, 1550-6606, , 2009

PMID:19234209

Open Access

Dicer-dependent microRNA pathway safeguards regulatory T cell function.
Liston A, Lu LF, O'Carroll D, Tarakhovsky A, Rudensky AY

Regulatory T (T reg) cells are indispensable for preventing autoimmunity. Incumbent to this role is the ability of T reg cells to exert their suppressor function under inflammatory conditions. We found that T reg cell-mediated tolerance is critically dependent on the Dicer-controlled microRNA (miRNA) pathway. Depletion of miRNA within the T reg cell lineage resulted in fatal autoimmunity indistinguishable from that in T reg cell-deficient mice. In disease-free mice lacking Dicer in all T cells or harboring both Dicer-deficient and -sufficient T reg cells, Dicer-deficient T reg cells were suppressive, albeit to a lesser degree, whereas their homeostatic potential was diminished as compared with their Dicer-sufficient counterparts. However, in diseased mice, Dicer-deficient T reg cells completely lost suppressor capacity. Thus, miRNA preserve the T reg cell functional program under inflammatory conditions.

+ View Abstract

The Journal of experimental medicine, 205, 1540-9538, , 2008

PMID:18725526

Open Access

Differentiation of regulatory Foxp3+ T cells in the thymic cortex.
Liston A, Nutsch KM, Farr AG, Lund JM, Rasmussen JP, Koni PA, Rudensky AY

Regulatory Foxp3(+) T cells (T(R)) are indispensable for preventing autoimmune pathology in multiple organs and tissues. During thymic differentiation T cell receptor (TCR)-ligand interactions within a certain increased affinity range, in conjunction with gammac-containing cytokine receptor signals, induce Foxp3 expression and thereby commit developing thymocytes to the T(R) lineage. The contribution of distinct MHC class II-expressing accessory cell types to the differentiation process of Foxp3(+) thymocytes remains controversial, because a unique role in this process has been ascribed to either thymic dendritic cells (tDC) or to medullary thymic epithelial cells (mTEC). Furthermore, it was suggested that the thymic medulla, where the bulk of the negative selection of self-reactive thymocytes takes place, provides a specialized microenvironment supporting T(R) differentiation. Here, we report that the cortex, as defined by cortical thymic epithelial cells (cTEC), is sufficient for supporting T(R) differentiation. MHC class II expression restricted to both cTEC and mTEC or to cTEC alone did not significantly affect the numbers of Foxp3(+) thymocytes. Furthermore, genetic or pharmacologic blockade of thymocyte migration resulted in a prominent accumulation of Foxp3(+) thymocytes in the cortex, demonstrating that secondary signals required for Foxp3 up-regulation exist in the cortex. Our results suggest that mTEC or tDC do not serve as a cell type singularly responsible for T(R) differentiation and that neither the cortex nor the medulla exclusively provides an environment suitable for Foxp3 induction. Instead, multiple accessory cell types probably contribute to the thymic generation of regulatory Foxp3(+) T cells.

+ View Abstract

Proceedings of the National Academy of Sciences of the United States of America, 105, 1091-6490, , 2008

PMID:18695219

Open Access

Unravelling the association of partial T-cell immunodeficiency and immune dysregulation.
Liston A, Enders A, Siggs OM

Partial T-cell immunodeficiencies constitute a heterogeneous cluster of disorders characterized by an incomplete reduction in T-cell number or activity. The immune deficiency component of these diseases is less severe than that of the severe T-cell immunodeficiencies and therefore some ability to respond to infectious organisms is retained. Unlike severe T-cell immunodeficiencies, however, partial immunodeficiencies are commonly associated with hyper-immune dysregulation, including autoimmunity, inflammatory diseases and elevated IgE production. This causative association is counter-intuitive--immune deficiencies are caused by loss-of-function changes to the T-cell component, whereas the coincident autoimmune symptoms are the consequence of gain-of-function changes. This Review details the genetic basis of partial T -cell immunodeficiencies and draws on recent advances in mouse models to propose mechanisms by which a reduction in T-cell numbers or function may disturb the population-dependent balance between activation and tolerance.

+ View Abstract

Nature reviews. Immunology, 8, 1474-1741, , 2008

PMID:18551129

Autoimmunity: beyond the immune system.
Liston A

Immunology and cell biology, 86, 0818-9641, , 0

PMID:18301386

Opposing functions of the T cell receptor kinase ZAP-70 in immunity and tolerance differentially titrate in response to nucleotide substitutions.
Siggs OM, Miosge LA, Yates AL, Kucharska EM, Sheahan D, Brdicka T, Weiss A, Liston A, Goodnow CC

Null mutations that cripple T cell receptor (TCR) signaling explain rare primary immunodeficiencies, but it is not understood why more common polymorphisms that lead to subtle TCR signaling defects are paradoxically associated with autoimmunity. Here we analyzed how a series of Zap70 variants with step-wise decreases in TCR signaling impacted upon opposing TCR functions of immunity and tolerance. One Zap70 variant, murdock, moderately decreased TCR signaling and thymic selection without compromising immunological tolerance, whereas a more severe Zap70 defect, mrtless, abolished thymic-positive selection and led to immunodeficiency. Signaling capacities between these two thresholds disproportionately compromised negative selection and Foxp3(+) regulatory T cell formation, creating a cellular imbalance between immunogenic and tolerogenic functions that resulted in the excessive production of autoantibodies and immunoglobulin E (IgE). The pleiotropic functions of ZAP-70 and their differential response to graded variation provide a paradigm for understanding the complex outcomes of human genetic variation.

+ View Abstract

Immunity, 27, 1074-7613, , 2007

PMID:18093540

Open Access

Tracing the action of IL-2 in tolerance to islet-specific antigen.
Liston A, Siggs OM, Goodnow CC

Genetic variants of interleukin 2 (IL-2) and its receptor are associated with murine and human susceptibility to Type 1 diabetes, yet the role of IL-2 in controlling pancreatic islet-reactive T cells is unknown. Here, we develop a model where IL-2 deficiency precipitates a breakdown of self-tolerance and progression to diabetes, and its action upon diabetogenic islet-specific CD4 T cells can be tracked. We find that IL-2 is not required for Aire-dependent thymic clonal deletion of high-avidity diabetogenic clones, but is essential for thymic formation of islet-specific Foxp3-expressing CD4 T cells. The absence of IL-2 results in the expansion of low-avidity Foxp3(-) islet-reactive CD4 T cells. The mechanism by which IL-2 prevents diabetes is therefore through the establishment of a repertoire of islet-reactive Foxp3(+) T cells within the thymus, and limitation of the peripheral activation of low-avidity islet-reactive T cells that normally escape thymic negative selection.

+ View Abstract

Immunology and cell biology, 85, 0818-9641, , 2007

PMID:17372610

Lack of Foxp3 function and expression in the thymic epithelium.
Liston A, Farr AG, Chen Z, Benoist C, Mathis D, Manley NR, Rudensky AY

Foxp3 is essential for the commitment of differentiating thymocytes to the regulatory CD4(+) T (T reg) cell lineage. In humans and mice with a genetic Foxp3 deficiency, absence of this critical T reg cell population was suggested to be responsible for the severe autoimmune lesions. Recently, it has been proposed that in addition to T reg cells, Foxp3 is also expressed in thymic epithelial cells where it is involved in regulation of early thymocyte differentiation and is required to prevent autoimmunity. Here, we used genetic tools to demonstrate that the thymic epithelium does not express Foxp3. Furthermore, we formally showed that genetic abatement of Foxp3 in the hematopoietic compartment, i.e. in T cells, is both necessary and sufficient to induce the autoimmune lesions associated with Foxp3 loss. In contrast, deletion of a conditional Foxp3 allele in thymic epithelial cells did not result in detectable changes in thymocyte differentiation or pathology. Therefore, in mice the only known role for Foxp3 remains promotion of T reg cell differentiation within the T cell lineage, whereas there is no role for Foxp3 in thymic epithelial cells.

+ View Abstract

The Journal of experimental medicine, 204, 0022-1007, , 2007

PMID:17353370

Open Access

Thymic development and peripheral homeostasis of regulatory T cells.
Liston A, Rudensky AY

The development and maintenance of regulatory T (T-reg) cells is crucial for determining the level of reactivity in the immune system. Until recently, however, surprisingly little was known about the factors involved in the development of these cells in the thymus or the mechanisms that maintain them in the periphery. Studies have now demonstrated that thymic development of T-reg cells is facilitated by TCRs with increased affinity for self-peptide-MHC complexes. Increased TCR affinity alone, however, is not sufficient to support the development of T-reg cells, and external factors such as CD80 and CD86, ligands for co-stimulatory receptor CD28, and interleukin 2 are required. These factors are also needed to maintain the T-reg cell subset in the periphery.

+ View Abstract

Current opinion in immunology, 19, 0952-7915, , 2007

PMID:17306520

Impairment of organ-specific T cell negative selection by diabetes susceptibility genes: genomic analysis by mRNA profiling.
Liston A, Hardy K, Pittelkow Y, Wilson SR, Makaroff LE, Fahrer AM, Goodnow CC

T cells in the thymus undergo opposing positive and negative selection processes so that the only T cells entering circulation are those bearing a T cell receptor (TCR) with a low affinity for self. The mechanism differentiating negative from positive selection is poorly understood, despite the fact that inherited defects in negative selection underlie organ-specific autoimmune disease in AIRE-deficient people and the non-obese diabetic (NOD) mouse strain

+ View Abstract

Genome biology, 8, 1474-760X, , 2007

PMID:17239257

Open Access

Developmental kinetics, turnover, and stimulatory capacity of thymic epithelial cells.
Gray DH, Seach N, Ueno T, Milton MK, Liston A, Lew AM, Goodnow CC, Boyd RL

Despite the importance of thymic stromal cells to T-cell development, relatively little is known about their biology. Here, we use single-cell analysis of stromal cells to analyze extensive changes in the number and composition of thymic stroma throughout life, revealing a surprisingly dynamic population. Phenotypic progression of thymic epithelial subsets was assessed at high resolution in young mice to provide a developmental framework. The cellular and molecular requirements of adult epithelium were studied, using various mutant mice to demonstrate new cross talk checkpoints dependent on RelB in the cortex and CD40 in the medulla. With the use of Ki67 and BrdU labeling, the turnover of thymic epithelium was found to be rapid, but then diminished on thymic involution. The various defects in stromal turnover and composition that accompanied involution were rapidly reversed following sex steroid ablation. Unexpectedly, mature cortical and medullary epithelium showed a potent capacity to stimulate naive T cells, comparable to that of thymic dendritic cells. Overall, these studies show that the thymic stroma is a surprisingly dynamic population and may have a more direct role in negative selection than previously thought.

+ View Abstract

Blood, 108, 0006-4971, , 2006

PMID:16896157

Open Access

The why and how of thymocyte negative selection.
Siggs OM, Makaroff LE, Liston A

The generation of T cell receptor (TCR) sequence diversity is the strength of adaptive immunity, yet is also the Achilles' heel. To purge highly self-reactive T cells from the immune system, generation of diversity has coevolved with a mechanism of negative selection. Recent studies have revealed new insights addressing the why and how of negative selection by examining situations in which negative selection has failed in human and animals models of autoimmunity. Both thymocyte extrinsic and intrinsic mechanisms are required to restrict the TCR repertoire to a non-autoreactive set. Negative selection also ensures that T cells emerge with receptors that are focussed on the peptide moiety of MHC-peptide complexes.

+ View Abstract

Current opinion in immunology, 18, 0952-7915, , 2006

PMID:16459069

Genetic lesions in thymic T cell clonal deletion and thresholds for autoimmunity.
Liston A, Goodnow CC

The cause of common polygenic autoimmune diseases is poorly understood because of genetic and cellular complexity in humans and animals. We have investigated the mechanisms of two genetic causes of organ-specific autoimmunity by tracking the fate of high avidity organ-specific CD4 T cells using a transgenic mouse model. Firstly, we have found that an Idd-associated duster of loci from the NOD strain causes a T cell intrinsic failure to delete during in vivo encounter with high-avidity autoantigen, a trait distinguished by the failure to induce the pro-apoptotic gene Bim. Secondly, we have found that inactivation of the autoimmune regulator (Aire) gene reduces the level of thymic expression of organ-specific genes, in a gene-dose dependent manner. In this paper we describe a model relating efficiency of thymic deletion and susceptibility to autoimmunity. Using this model, subtle quantitative trait loci can have an additive effect on each of the parameters of thymic deletion, and the result of interaction between subtle modifications in the multiple parameters can result in large changes in the susceptibility to autoimmunity.

+ View Abstract

Novartis Foundation symposium, 267, 1528-2511, , 2005

PMID:15999807

Genetic lesions in T-cell tolerance and thresholds for autoimmunity.
Liston A, Lesage S, Gray DH, Boyd RL, Goodnow CC

The cause of common organ-specific autoimmune diseases is poorly understood because of genetic and cellular complexity in humans and animals. Recent advances in the understanding of the mechanisms of the defects underlying autoimmune disease in autoimmune polyendocrinopathy syndrome type 1 and non-obese diabetic mice suggest that failures in central tolerance play a key role in predisposition towards organ-specific autoimmunity. The lessons from such rare monogenic autoimmune disorders and well-characterized polygenic traits demonstrate how subtle quantitative trait loci can result in large changes in the susceptibility to autoimmunity. These data allow us to propose a model relating efficiency of thymic deletion to T-cell tolerance and susceptibility to autoimmunity.

+ View Abstract

Immunological reviews, 204, 0105-2896, , 2005

PMID:15790352

Generalized resistance to thymic deletion in the NOD mouse; a polygenic trait characterized by defective induction of Bim.
Liston A, Lesage S, Gray DH, O'Reilly LA, Strasser A, Fahrer AM, Boyd RL, Wilson J, Baxter AG, Gallo EM, Crabtree GR, Peng K, Wilson SR, Goodnow CC

The cause of common polygenic autoimmune diseases is not understood because of genetic and cellular complexity. Here, we pinpoint the action of a subset of autoimmune susceptibility loci in the NOD mouse strain linked to D1mit181, D2mit490, D7mit101, and D15mit229, which cause a generalized resistance to thymic deletion in vivo that applies equally to Aire-induced organ-specific gene products in the thymic medulla and to systemic antigens expressed at high levels throughout the thymus and affects CD4(+), CD4(+)8(+), and CD4(+)25(+) thymocytes. Resistance to thymic deletion does not reflect a general deficit in TCR signaling to calcineurin- or ERK-induced genes, imbalance in constitutive regulators of apoptosis, nor excessive signaling to prosurvival genes but is distinguished by failure to induce the proapoptotic gene and protein, Bim, during in vivo encounter with high-avidity autoantigen. These findings establish defects in thymic deletion and Bim induction as a key mechanism in the pathogenesis of autoimmunity.

+ View Abstract

Immunity, 21, 1074-7613, , 2004

PMID:15589170

Open Access

Gene dosage--limiting role of Aire in thymic expression, clonal deletion, and organ-specific autoimmunity.
Liston A, Gray DH, Lesage S, Fletcher AL, Wilson J, Webster KE, Scott HS, Boyd RL, Peltonen L, Goodnow CC

Inactivation of the autoimmune regulator (Aire) gene causes a rare recessive disorder, autoimmune polyendocrine syndrome 1 (APS1), but it is not known if Aire-dependent tolerance mechanisms are susceptible to the quantitative genetic changes thought to underlie more common autoimmune diseases. In mice with a targeted mutation, complete loss of Aire abolished expression of an insulin promoter transgene in thymic epithelium, but had no effect in pancreatic islets or the testes. Loss of one copy of Aire diminished thymic expression of the endogenous insulin gene and the transgene, resulting in a 300% increase in islet-reactive CD4 T cells escaping thymic deletion in T cell receptor transgenic mice, and dramatically increased progression to diabetes. Thymic deletion induced by antigen under control of the thyroglobulin promoter was abolished in Aire homozygotes and less efficient in heterozygotes, providing an explanation for thyroid autoimmunity in APS1. In contrast, Aire deficiency had no effect on thymic deletion to antigen controlled by a systemic H-2K promoter. The sensitivity of Aire-dependent thymic deletion to small reductions in function makes this pathway a prime candidate for more subtle autoimmune quantitative trait loci, and suggests that methods to increase Aire activity would be a potent strategy to lower the incidence of organ-specific autoimmunity.

+ View Abstract

The Journal of experimental medicine, 200, 0022-1007, , 2004

PMID:15492124

Open Access

Subversion of the chemokine world by microbial pathogens.
Liston A, McColl S

It is well known that microbial pathogens are able to subvert the host immune system in order to increase microbial replication and propagation. Recent research indicates that another arm of the immune response, that of the chemokine system, is also subject to this sabotage, and is undermined by a range of microbial pathogens, including viruses, bacteria, and parasites. Currently, it is known that the chemokine system is being challenged by a number of mechanisms, and still more are likely to be discovered with further research. Here we first review the general mechanisms by which microbial pathogens bypass mammalian chemokine defences. Broadly, these can be grouped as viral chemokine interacting proteins, microbial manipulation of host chemokine and chemokine receptor expression, microbial blockade of host chemokine receptor signalling, and the largely hypothetical mechanisms of microbial enhancement of host anti-chemokine networks (including digestion, antagonism, and neutralisation of host chemokines and chemokine receptors). We then discuss the potential results of these interactions in terms of outcome of infection.

+ View Abstract

BioEssays : news and reviews in molecular, cellular and developmental biology, 25, 0265-9247, , 2003

PMID:12717818

Aire regulates negative selection of organ-specific T cells.
Liston A, Lesage S, Wilson J, Peltonen L, Goodnow CC

Autoimmune polyendocrinopathy syndrome type 1 is a recessive Mendelian disorder resulting from mutations in a novel gene, AIRE, and is characterized by a spectrum of organ-specific autoimmune diseases. It is not known what tolerance mechanisms are defective as a result of AIRE mutation. By tracing the fate of autoreactive CD4+ T cells with high affinity for a pancreatic antigen in transgenic mice with an Aire mutation, we show here that Aire deficiency causes almost complete failure to delete the organ-specific cells in the thymus. These results indicate that autoimmune polyendocrinopathy syndrome 1 is caused by failure of a specialized mechanism for deleting forbidden T cell clones, establishing a central role for this tolerance mechanism.

+ View Abstract

Nature immunology, 4, 1529-2908, , 2003

PMID:12612579