Life Sciences Research for Lifelong Health

Publications

The Babraham Institute Publications database contains details of all publications resulting from our research groups and scientific services.

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Title / Authors / Details Open Access Download

Who plays the ferryman: ATG2 channels lipids into the forming autophagosome.
Ktistakis NT

Expansion of the autophagosomal membrane requires a mechanism to supply lipids while excluding most membrane proteins. In this issue, Valverde et al. (2019. https://doi.org/10.1083/jcb.201811139) identify ATG2, a member of the autophagy-related protein family, as a lipid transfer protein and provide important novel insights on how autophagosomes grow.

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The Journal of cell biology, , 1540-8140, , 2019

PMID: 31076453

MEK1/2 inhibitor withdrawal reverses acquired resistance driven by BRAF amplification whereas KRAS amplification promotes EMT-chemoresistance.
Sale MJ, Balmanno K, Saxena J, Ozono E, Wojdyla K, McIntyre RE, Gilley R, Woroniuk A, Howarth KD, Hughes G, Dry JR, Arends MJ, Caro P, Oxley D, Ashton S, Adams DJ, Saez-Rodriguez J, Smith PD, Cook SJ

Acquired resistance to MEK1/2 inhibitors (MEKi) arises through amplification of BRAF or KRAS to reinstate ERK1/2 signalling. Here we show that BRAF amplification and MEKi resistance are reversible following drug withdrawal. Cells with BRAF amplification are addicted to MEKi to maintain a precise level of ERK1/2 signalling that is optimal for cell proliferation and survival, and tumour growth in vivo. Robust ERK1/2 activation following MEKi withdrawal drives a p57-dependent G1 cell cycle arrest and senescence or expression of NOXA and cell death, selecting against those cells with amplified BRAF. p57 expression is required for loss of BRAF amplification and reversal of MEKi resistance. Thus, BRAF amplification confers a selective disadvantage during drug withdrawal, validating intermittent dosing to forestall resistance. In contrast, resistance driven by KRAS amplification is not reversible; rather ERK1/2 hyperactivation drives ZEB1-dependent epithelial-to-mesenchymal transition and chemoresistance, arguing strongly against the use of drug holidays in cases of KRAS amplification.

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Nature communications, 10, 2041-1723, 2030, 2019

PMID: 31048689

Macropinocytosis and autophagy crosstalk in nutrient scavenging.
Florey O, Overholtzer M

Adaptive strategies used by cells to scavenge and recycle essential nutrients are important for survival in nutrient-depleted environments such as cancer tissues. Autophagy and macropinocytosis are two major mechanisms that promote nutrient recycling and scavenging, which share considerable, yet poorly understood, cross-regulation. Here we review recent findings that connect these starvation response mechanisms and discuss the implications of their crosstalk. This article is part of the Theo Murphy meeting issue 'Macropinocytosis'.

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Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 374, 1471-2970, 20180154, 2019

PMID: 30967004

Entosis Controls a Developmental Cell Clearance in C. elegans.
Lee Y, Hamann JC, Pellegrino M, Durgan J, Domart MC, Collinson LM, Haynes CM, Florey O, Overholtzer M

Metazoan cell death mechanisms are diverse and include numerous non-apoptotic programs. One program called entosis involves the invasion of live cells into their neighbors and is known to occur in cancers. Here, we identify a developmental function for entosis: to clear the male-specific linker cell in C. elegans. The linker cell leads migration to shape the gonad and is removed to facilitate fusion of the gonad to the cloaca. We find that the linker cell is cleared in a manner involving cell-cell adhesions and cell-autonomous control of uptake through linker cell actin. Linker cell entosis generates a lobe structure that is deposited at the site of gonad-to-cloaca fusion and is removed during mating. Inhibition of lobe scission inhibits linker cell death, demonstrating that the linker cell invades its host while alive. Our findings demonstrate a developmental function for entosis: to eliminate a migrating cell and facilitate gonad-to-cloaca fusion, which is required for fertility.

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Cell reports, 26, 2211-1247, 3212-3220.e4, 2019

PMID: 30893595

ER platforms mediating autophagosome generation.
Ktistakis NT

The origin of the autophagosomal membrane started to be debated by scientists working in the field within one year of the modern definition of autophagy in 1963. There is now converging evidence from older and newer studies that the endoplasmic reticulum is involved in formation of autophagosomes. Thus, it is possible to trace from early morphological work - done without the benefit of molecular descriptions - to recent studies - dissecting how specific proteins nucleate autophagosome biogenesis - a long series of experimental findings that are beginning to answer the 55-year old question with some confidence. The view that has emerged is that specialised regions of the endoplasmic reticulum, in dynamic cross talk with most intracellular organelles via membrane contact sites, provide a platform for autophagosome biogenesis.

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Biochimica et biophysica acta. Molecular and cell biology of lipids, , 1879-2618, , 2019

PMID: 30890442

Phosphorylation of Syntaxin 17 by TBK1 Controls Autophagy Initiation.
Kumar S, Gu Y, Abudu YP, Bruun JA, Jain A, Farzam F, Mudd M, Anonsen JH, Rusten TE, Kasof G, Ktistakis N, Lidke KA, Johansen T, Deretic V

Syntaxin 17 (Stx17) has been implicated in autophagosome-lysosome fusion. Here, we report that Stx17 functions in assembly of protein complexes during autophagy initiation. Stx17 is phosphorylated by TBK1 whereby phospho-Stx17 controls the formation of the ATG13FIP200 mammalian pre-autophagosomal structure (mPAS) in response to induction of autophagy. TBK1 phosphorylates Stx17 at S202. During autophagy induction, Stx17 transfers from the Golgi, where its steady-state pools localize, to the ATG13FIP200 mPAS. Stx17 was in complexes with ATG13 and FIP200, whereas its non-phosphorylatable mutant Stx17 was not. Stx17 or TBK1 knockouts blocked ATG13 and FIP200 puncta formation. Stx17 or TBK1 knockouts reduced the formation of ATG13 protein complexes with FIP200 and ULK1. Endogenous Stx17 colocalized with LC3B following induction of autophagy. Stx17 knockout diminished LC3 response and reduced sequestration of the prototypical bulk autophagy cargo lactate dehydrogenase. We conclude that Stx17 is a TBK1 substrate and that together they orchestrate assembly of mPAS.

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Developmental cell, , 1878-1551, , 2019

PMID: 30827897

Frontline Science: TNF-α and GM-CSF1 priming augments the role of SOS1/2 in driving activation of Ras, PI3K-γ, and neutrophil proinflammatory responses.
Suire S, Baltanas FC, Segonds-Pichon A, Davidson K, Santos E, Hawkins PT, Stephens LR

Circulating neutrophils are, by necessity, quiescent and relatively unresponsive to acute stimuli. In regions of inflammation, mediators can prime neutrophils to react to acute stimuli with stronger proinflammatory, pathogen-killing responses. In neutrophils G protein-coupled receptor (GPCR)-driven proinflammatory responses, such as reactive oxygen species (ROS) formation and accumulation of the key intracellular messenger phosphatidylinositol (3,4,5)-trisphosphate (PIP ), are highly dependent on PI3K-γ, a Ras-GTP, and Gβγ coincidence detector. In unprimed cells, the major GPCR-triggered activator of Ras is the Ras guanine nucleotide exchange factor (GEF), Ras guanine nucleotide releasing protein 4 (RasGRP4). Although priming is known to increase GPCR-PIP signaling, the mechanisms underlying this augmentation remain unclear. We used genetically modified mice to address the role of the 2 RasGEFs, RasGRP4 and son of sevenless (SOS)1/2, in neutrophil priming. We found that following GM-CSF/TNFα priming, RasGRP4 had only a minor role in the enhanced responses. In contrast, SOS1/2 acquired a substantial role in ROS formation, PIP accumulation, and ERK activation in primed cells. These results suggest that SOS1/2 signaling plays a key role in determining the responsiveness of neutrophils in regions of inflammation.

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Journal of leukocyte biology, , 1938-3673, , 2019

PMID: 30720883

Open Access

The circadian clock components BMAL1 and REV-ERBα regulate flavivirus replication.
Zhuang X, Magri A, Hill M, Lai AG, Kumar A, Rambhatla SB, Donald CL, Lopez-Clavijo AF, Rudge S, Pinnick K, Chang WH, Wing PAC, Brown R, Qin X, Simmonds P, Baumert TF, Ray D, Loudon A, Balfe P, Wakelam M, Butterworth S, Kohl A, Jopling CL, Zitzmann N, McKeating JA

The circadian clock regulates immune responses to microbes and affects pathogen replication, but the underlying molecular mechanisms are not well understood. Here we demonstrate that the circadian components BMAL1 and REV-ERBα influence several steps in the hepatitis C virus (HCV) life cycle, including particle entry into hepatocytes and RNA genome replication. Genetic knock out of Bmal1 and over-expression or activation of REV-ERB with synthetic agonists inhibits the replication of HCV and the related flaviruses dengue and Zika via perturbation of lipid signaling pathways. This study highlights a role for the circadian clock component REV-ERBα in regulating flavivirus replication.

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Nature communications, 10, 2041-1723, 377, 2019

PMID: 30670689

Open Access

LIPID MAPS: Serving the next generation of lipid researchers with tools, resources, data, and training.
O'Donnell VB, Dennis EA, Wakelam MJO, Subramaniam S

Lipids are increasingly recognized as dynamic, critical metabolites affecting human physiology and pathophysiology. LIPID MAPS is a free resource dedicated to serving the lipid research community.

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Science signaling, 12, 1937-9145, , 2019

PMID: 30622195

Imaging Noncanonical Autophagy and LC3-Associated Phagocytosis in Cultured Cells.
Jacquin E, Fletcher K, Florey O

Monitoring of ATG8 proteins by western blotting and immunofluorescence microscopy are the most common methods to monitor the autophagy pathway. However, it has recently been shown that ATG8 proteins can be lipidated to non-autophagosome, single-membrane compartments through a noncanonical autophagy pathway. This is commonly found to occur during macro-endocytic processes such as phagocytosis, where it has been termed LC3-associated phagocytosis, and upon lysosomotropic drug treatment. Therefore, care is required when interpreting data based on ATG8 in order to conclude whether a signal relates to the canonical or noncanonical pathway. Here we provide methods to monitor noncanonical autophagy through fluorescence microscopy.

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Methods in molecular biology (Clifton, N.J.), 1880, 1940-6029, 295-303, 2019

PMID: 30610705

Over-expressed, N-terminally truncated BRAF is detected in the nucleus of cells with nuclear phosphorylated MEK and ERK.
Hey F, Andreadi C, Noble C, Patel B, Jin H, Kamata T, Straatman K, Luo J, Balmanno K, Jones DTW, Collins VP, Cook SJ, Caunt CJ, Pritchard C

BRAF is a cytoplasmic protein kinase, which activates the MEK-ERK signalling pathway. Deregulation of the pathway is associated with the presence of mutations in human cancer, the most common being , although structural rearrangements, which remove N-terminal regulatory sequences, have also been reported. RAF-MEK-ERK signalling is normally thought to occur in the cytoplasm of the cell. However, in an investigation of BRAF localisation using fluorescence microscopy combined with subcellular fractionation of Green Fluorescent Protein (GFP)-tagged proteins expressed in NIH3T3 cells, surprisingly, we detected N-terminally truncated BRAF (ΔBRAF) in both nuclear and cytoplasmic compartments. In contrast, ΔCRAF and full-length, wild-type BRAF (BRAF) were detected at lower levels in the nucleus while full-length BRAF was virtually excluded from this compartment. Similar results were obtained using ΔBRAF tagged with the hormone-binding domain of the oestrogen receptor (hbER) and with the KIAA1549-ΔBRAF translocation mutant found in human pilocytic astrocytomas. Here we show that GFP-ΔBRAF nuclear translocation does not involve a canonical Nuclear Localisation Signal (NLS), but is suppressed by N-terminal sequences. Nuclear GFP-ΔBRAF retains MEK/ERK activating potential and is associated with the accumulation of phosphorylated MEK and ERK in the nucleus. In contrast, full-length GFP-BRAF and GFP-BRAF are associated with the accumulation of phosphorylated ERK but not phosphorylated MEK in the nucleus. These data have implications for cancers bearing single nucleotide variants or N-terminal deleted structural variants of .

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Heliyon, 4, 2405-8440, e01065, 2018

PMID: 30603699

Macropinocytosis and autophagy crosstalk in nutrient scavenging
Florey O, Overholtzer M

Adaptive strategies used by cells to scavenge and recycle essential nutrients are important for survival in nutrient-depleted environments such as cancer tissues. Autophagy and macropinocytosis are two major mechanisms that promote nutrient recycling and scavenging, which share considerable, yet poorly understood, cross-regulation. Here we review recent findings that connect these starvation response mechanisms and discuss the implications of their crosstalk. This article is part of the Theo Murphy meeting issue ‘Macropinocytosis’.

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Philosophical Transactions of the Royal Society B: Biological Sciences, 374, 1765, , 2018

PMID: 30478386
DOI: https://doi.org/10.1098/rstb.2018.0154

Open Access

The double life of autophagy proteins.
Florey O

Nature microbiology, 3, 2058-5276, 1334-1335, 2018

PMID: 30478385

3D growth of cancer cells elicits sensitivity to kinase inhibitors but not lipid metabolism modifiers.
Jones DT, Valli A, Haider S, Zang Q, Smethurst E, Schug ZT, Peck B, Aboagye EO, Critchlow SE, Schulze A, Gottlieb E, Wakelam MJO, Adrian HL

Tumour cells exhibit altered lipid metabolism compared to normal cells. Cell signalling kinases are important for regulating lipid synthesis and energy storage. How upstream kinases regulate lipid content, versus direct targeting of lipid metabolising enzymes, is currently unexplored. We evaluated intracellular lipid concentrations in prostate and breast tumour spheroids, treated with drugs directly inhibiting metabolic enzymes FASN, ACC, DGAT and PDHK, or cell signalling kinase enzymes PI3K, AKT and mTOR with lipidomic analysis. We assessed whether baseline lipid profiles corresponded to inhibitors' effectiveness in modulating lipid profiles in 3D-growth, and their relationship to therapeutic activity. Inhibitors against PI3K, AKT and mTOR significantly inhibited MDA-MB-468 and PC3 cell growth in 2D and 3D spheroid growth, while moderately altering lipid content. Conversely, metabolism inhibitors against FASN and DGAT altered lipid content most effectively, while only moderately inhibiting growth compared to kinase inhibitors. The FASN and ACC inhibitors' effectiveness in MDA-MB-468, versus PC3, suggested the former depended more on synthesis whereas the latter may salvage lipids. Although baseline lipid profiles didn't predict growth effects, lipid changes on therapy matched the growth effects of FASN and DGAT inhibitors. Several phospholipids, including phosphatidylcholine, were also upregulated following treatment, possibly via the Kennedy pathway. As this promotes tumour growth, combination studies should include drugs targeting it. Two-dimensional drug screening may miss important metabolism inhibitors or underestimate their potency. Clinical studies should consider serial measurements of tumour lipids to prove target modulation. Pre-therapy tumour classification by de novo lipid synthesis versus uptake may help demonstrate efficacy.

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Molecular cancer therapeutics, , 1538-8514, , 2018

PMID: 30478149

Quantitation of class IA PI3Ks in mice reveals p110-free-p85s and isoform-selective subunit associations and recruitment to receptors.
Tsolakos N, Durrant TN, Chessa T, Suire SM, Oxley D, Kulkarni S, Downward J, Perisic O, Williams RL, Stephens L, Hawkins PT

Class IA PI3Ks have many roles in health and disease. The rules that govern intersubunit and receptor associations, however, remain unclear. We engineered mouse lines in which individual endogenous class IA PI3K subunits were C-terminally tagged with 17aa that could be biotinylated in vivo. Using these tools we quantified PI3K subunits in streptavidin or PDGFR pull-downs and cell lysates. This revealed that p85α and β bound equivalently to p110α or p110β but p85α bound preferentially to p110δ. p85s were found in molar-excess over p110s in a number of contexts including MEFs (p85β, 20%) and liver (p85α, 30%). In serum-starved MEFs, p110-free-p85s were preferentially, compared with heterodimeric p85s, bound to PDGFRs, consistent with in vitro assays that demonstrated they bound PDGFR-based tyrosine-phosphorylated peptides with higher affinity and co-operativity; suggesting they may act to tune a PI3K activation threshold. p110α-heterodimers were recruited 5-6× more efficiently than p110β-heterodimers to activated PDGFRs in MEFs or to PDGFR-based tyrosine-phosphorylated peptides in MEF-lysates. This suggests that PI3Kα has a higher affinity for relevant tyrosine-phosphorylated motifs than PI3Kβ. Nevertheless, PI3Kβ contributes substantially to acute PDGF-stimulation of PIP and PKB in MEFs because it is synergistically, and possibly sequentially, activated by receptor-recruitment and small GTPases (Rac/CDC42) via its RBD, whereas parallel activation of PI3Kα is independent of its RBD. These results begin to provide molecular clarity to the rules of engagement between class IA PI3K subunits in vivo and past work describing "excess p85," p85α as a tumor suppressor, and differential receptor activation of PI3Kα and PI3Kβ.

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Proceedings of the National Academy of Sciences of the United States of America, 115, 1091-6490, 12176-12181, 2018

PMID: 30442661

Open Access

Alpha-synuclein fibrils recruit TBK1 and OPTN to lysosomal damage sites and induce autophagy in microglial cells.
Bussi C, Peralta Ramos JM, Arroyo DS, Gallea JI, Ronchi P, Kolovou A, Wang JM, Florey O, Celej MS, Schwab Y, Ktistakis NT, Iribarren P

Autophagic dysfunction and protein aggregation have been linked to several neurodegenerative disorders, but the exact mechanisms and causal connections are not clear and most work was done in neurons and not in microglial cells. Here we report that exogenous fibrillar but not monomeric alpha-synuclein (AS) induces autophagy in microglial cells. We extensively studied the dynamics of this response by both live-cell imaging and correlative light-electron microscopy (CLEM) and found that it correlates with lysosomal damage and is characterised by the recruitment of the selective autophagy-associated proteins TANK-binding kinase 1 (TBK1) and Optineurin (OPTN) to ubiquitinated lysosomes. In addition, we observed that LC3 recruitment to damaged lysosomes was dependent on TBK1 activity. In these fibrillar AS-treated cells, autophagy inhibition impairs mitochondrial function and leads to microglial cell death. Our results suggest that microglial autophagy is induced in response to lysosomal damage caused by persistent accumulation of AS fibrils. Importantly, triggering of the autophagic response appears to be an attempt at lysosomal quality control and not for engulfment of fibrillar AS.

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Journal of cell science, , 1477-9137, , 2018

PMID: 30404831

The ATG5-binding and coiled coil domains of ATG16L1 maintain autophagy and tissue homeostasis in mice independently of the WD domain required for LC3-associated phagocytosis.
Rai S, Arasteh M, Jefferson M, Pearson T, Wang Y, Zhang W, Bicsak B, Divekar D, Powell PP, Nauman R, Beraza N, Carding SR, Florey O, Mayer U, Wileman T

Macroautophagy/autophagy delivers damaged proteins and organelles to lysosomes for degradation, and plays important roles in maintaining tissue homeostasis by reducing tissue damage. The translocation of LC3 to the limiting membrane of the phagophore, the precursor to the autophagosome, during autophagy provides a binding site for autophagy cargoes, and facilitates fusion with lysosomes. An autophagy-related pathway called LC3-associated phagocytosis (LAP) targets LC3 to phagosome and endosome membranes during uptake of bacterial and fungal pathogens, and targets LC3 to swollen endosomes containing particulate material or apoptotic cells. We have investigated the roles played by autophagy and LAP in vivo by exploiting the observation that the WD domain of ATG16L1 is required for LAP, but not autophagy. Mice lacking the linker and WD domains, activate autophagy, but are deficient in LAP. The LAP mice survive postnatal starvation, grow at the same rate as littermate controls, and are fertile. The liver, kidney, brain and muscle of these mice maintain levels of autophagy cargoes such as LC3 and SQSTM1/p62 similar to littermate controls, and prevent accumulation of SQSTM1 inclusions and tissue damage associated with loss of autophagy. The results suggest that autophagy maintains tissue homeostasis in mice independently of LC3-associated phagocytosis. Further deletion of glutamate E230 in the coiled-coil domain required for WIPI2 binding produced mice with defective autophagy that survived neonatal starvation. Analysis of brain lysates suggested that interactions between WIPI2 and ATG16L1 were less critical for autophagy in the brain, which may allow a low level of autophagy to overcome neonatal lethality. Abbreviations: CCD: coiled-coil domain; CYBB/NOX2: cytochrome b-245: beta polypeptide; GPT/ALT: glutamic pyruvic transaminase: soluble; LAP: LC3-associated phagocytosis; LC3: microtubule-associated protein 1 light chain 3; MEF: mouse embryonic fibroblast; NOD: nucleotide-binding oligomerization domain; NADPH: nicotinamide adenine dinucleotide phosphate; RUBCN/Rubicon: RUN domain and cysteine-rich domain containing Beclin 1-interacting protein; SLE: systemic lupus erythematosus; SQSTM1/p62: sequestosome 1; TLR: toll-like receptor; TMEM: transmembrane protein; TRIM: tripartite motif-containing protein; UVRAG: UV radiation resistance associated gene; WD: tryptophan-aspartic acid; WIPI: WD 40 repeat domain: phosphoinositide interacting.

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Autophagy, , 1554-8635, 1-14, 2018

PMID: 30403914

CD151 regulates expression of FGFR2 in breast cancer cells via PKC-dependent pathways.
Sadej R, Lu X, Turczyk L, Novitskaya V, Lopez-Clavijo AF, Kordek R, Potemski P, Wakelam MJO, Romanska H, Berditchevski F

Expression of the tetraspanin CD151 is frequently upregulated in epithelial malignancies and correlates with poor prognosis. Here we report that CD151 is involved in regulation of the expression of fibroblast growth factor receptor 2 (FGFR2). Depletion of CD151 in breast cancer cells resulted in an increased level of FGFR2. Accordingly, an inverse correlation between CD151 and FGFR2 was observed in breast cancer tissues. CD151-dependent regulation of the FGFR2 expression relies on post-transcriptional mechanisms involving HuR/ELAVL1, a multifunctional RNA binding protein, and the assembly of processing bodies (P-bodies). Depletion of CD151 correlated with inhibition of PKC, a well-established downstream target of CD151. Accordingly, the levels of dialcylglycerol species were decreased in CD151-negative cells, and inhibition of PKC resulted in the increased expression of FGFR2. Whilst expression of FGFR2 itself did not correlate with any of the clinicopathological data, the FGFR2-/CD151+ patients are more likely to develop lymph node metastasis. Conversely, FGFR2-/CD151- patients demonstrated better overall survival. These results illustrate functional interdependency between CD151 complexes and FGFR2 and suggest a previously unsuspected role of CD151 in breast tumourigenesis.

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Journal of cell science, , 1477-9137, , 2018

PMID: 30257985

Genome organization and chromatin analysis identify transcriptional downregulation of insulin-like growth factor signaling as a hallmark of aging in developing B cells.
Koohy H, Bolland DJ, Matheson LS, Schoenfelder S, Stellato C, Dimond A, Várnai C, Chovanec P, Chessa T, Denizot J, Manzano Garcia R, Wingett SW, Freire-Pritchett P, Nagano T, Hawkins P, Stephens L, Elderkin S, Spivakov M, Fraser P, Corcoran AE, Varga-Weisz PD

Aging is characterized by loss of function of the adaptive immune system, but the underlying causes are poorly understood. To assess the molecular effects of aging on B cell development, we profiled gene expression and chromatin features genome-wide, including histone modifications and chromosome conformation, in bone marrow pro-B and pre-B cells from young and aged mice.

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Genome biology, 19, 1474-760X, 126, 2018

PMID: 30180872

Open Access

Targeting IKKβ in Cancer: Challenges and Opportunities for the Therapeutic Utilisation of IKKβ Inhibitors.
Prescott JA, Cook SJ

Deregulated NF-κB signalling is implicated in the pathogenesis of numerous human inflammatory disorders and malignancies. Consequently, the NF-κB pathway has attracted attention as an attractive therapeutic target for drug discovery. As the primary, druggable mediator of canonical NF-κB signalling the IKKβ protein kinase has been the historical focus of drug development pipelines. Thousands of compounds with activity against IKKβ have been characterised, with many demonstrating promising efficacy in pre-clinical models of cancer and inflammatory disease. However, severe on-target toxicities and other safety concerns associated with systemic IKKβ inhibition have thus far prevented the clinical approval of any IKKβ inhibitors. This review will discuss the potential reasons for the lack of clinical success of IKKβ inhibitors to date, the challenges associated with their therapeutic use, realistic opportunities for their future utilisation, and the alternative strategies to inhibit NF-κB signalling that may overcome some of the limitations associated with IKKβ inhibition.

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Cells, 7, 2073-4409, , 2018

PMID: 30142927

Open Access

MS-based lipidomics of human blood plasma - a community-initiated position paper to develop accepted guidelines.
Burla B, Arita M, Arita M, Bendt AK, Cazenave-Gassiot A, Dennis EA, Ekroos K, Han X, Ikeda K, Liebisch G, Lin MK, Loh TP, Meikle PJ, Orešič M, Quehenberger O, Shevchenko A, Torta F, Wakelam MJO, Wheelock CE, Wenk MR

Human blood is a self-regenerating, lipid-rich biologic fluid that is routinely collected in hospital settings. The inventory of lipid molecules found in blood plasma (plasma lipidome) offers insights into individual metabolism and physiology in health and disease. Disturbances in lipid metabolism also occur in conditions that are not directly linked to lipid metabolism; therefore, plasma lipidomics based on mass spectrometry (MS) is an emerging tool in an array of clinical diagnostics and disease management. However, challenges exist in the translation of such lipidomic data to clinical applications. These relate to the reproducibility, accuracy, and precision of lipid quantitation, study design, sample handling, and data sharing. This position paper emerged from a workshop that initiated a community-led process to elaborate and define a set of generally accepted guidelines for quantitative MS-based lipidomics of blood plasma or serum, with harmonization of data acquired on different instrumentation platforms in independent laboratories across laboratories as an ultimate goal. We hope that other fields may benefit from and follow such a precedent.

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Journal of lipid research, , 1539-7262, , 2018

PMID: 30115755

Open Access

C. elegans Eats Its Own Intestine to Make Yolk Leading to Multiple Senescent Pathologies.
Ezcurra M, Benedetto A, Sornda T, Gilliat AF, Au C, Zhang Q, van Schelt S, Petrache AL, Wang H, de la Guardia Y, Bar-Nun S, Tyler E, Wakelam MJ, Gems D

Aging (senescence) is characterized by the development of numerous pathologies, some of which limit lifespan. Key to understanding aging is discovery of the mechanisms (etiologies) that cause senescent pathology. In C. elegans, a major senescent pathology of unknown etiology is atrophy of its principal metabolic organ, the intestine. Here we identify a cause of not only this pathology but also of yolky lipid accumulation and redistribution (a form of senescent obesity): autophagy-mediated conversion of intestinal biomass into yolk. Inhibiting intestinal autophagy or vitellogenesis rescues both visceral pathologies and can also extend lifespan. This defines a disease syndrome leading to multimorbidity and contributing to late-life mortality. Activation of gut-to-yolk biomass conversion by insulin/IGF-1 signaling (IIS) promotes reproduction and senescence. This illustrates how major, IIS-promoted senescent pathologies in C. elegans can originate not from damage accumulation but from direct effects of futile, continued action of a wild-type biological program (vitellogenesis).

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Current biology : CB, , 1879-0445, , 2018

PMID: 30100339

Open Access

Removing physiological motion from intravital and clinical functional imaging data.
Warren SC, Nobis M, Magenau A, Mohammed YH, Herrmann D, Moran I, Vennin C, Conway JR, Mélénec P, Cox TR, Wang Y, Morton JP, Welch HC, Strathdee D, Anderson KI, Phan TG, Roberts MS, Timpson P

Intravital microscopy can provide unique insights into the function of biological processes in a native context. However, physiological motion caused by peristalsis, respiration and the heartbeat can present a significant challenge, particularly for functional readouts such as fluorescence lifetime imaging (FLIM), which require longer acquisition times to obtain a quantitative readout. Here, we present and benchmark , a versatile multi-platform software tool for image-based correction of sample motion blurring in both time resolved and conventional laser scanning fluorescence microscopy data in two and three dimensions. We show that is able to resolve intravital FLIM-FRET images of intra-abdominal organs in murine models and NADH autofluorescence of human dermal tissue imaging subject to a wide range of physiological motions. Thus, can enable FLIM imaging in situations where a stable imaging platform is not always possible and rescue previously discarded quantitative imaging data.

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eLife, 7, 2050-084X, , 2018

PMID: 29985127

Open Access

Host lipidome analysis during rhinovirus replication in human bronchial epithelial cells identifies potential therapeutic targets.
Nguyen A, Guedan A, Mousnier A, Swieboda D, Zhang Q, Horkai D, Le Novere N, Solari R, Wakelam MJO

In patients with asthma or chronic obstructive pulmonary disease rhinovirus infections can provoke acute worsening of disease and limited treatment options exist. Viral replication in the host cell induces significant remodeling of intracellular membranes, but few studies have explored this mechanistically or as a therapeutic opportunity. We performed unbiased lipidomic analysis on human bronchial epithelial cells infected over a 6 hour period with the RV-A1b strain of rhinovirus to determine changes in 493 distinct lipid species. Through pathway and network analysis we identified temporal changes in the apparent activities of a number of lipid metabolizing and signaling enzymes. In particular, analysis highlighted fatty acid synthesis and ceramide metabolism as potential anti-rhinoviral targets. To validate the importance of these enzymes in viral replication, we explored the effects of commercially-available enzyme inhibitors upon RV-A1b infection and replication. Ceranib-1, D609 and C75 were the most potent inhibitors, which confirmed that fatty acid synthase and ceramidase are potential inhibitory targets in rhinoviral infections. More broadly, this study demonstrates the potential of lipidomics and pathway analysis to identify novel targets to treat human disorders.

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Journal of lipid research, , 1539-7262, , 2018

PMID: 29946055

Open Access

Autophagy, Inflammation, and Metabolism (AIM) Center of Biomedical Research Excellence: supporting the next generation of autophagy researchers and fostering international collaborations.
Deretic V, Prossnitz E, Burge M, Campen MJ, Cannon J, Liu KJ, Sklar LA, Allers L, Garcia SA, Baehrecke EH, Behrends C, Cecconi F, Codogno P, Chen GC, Elazar Z, Eskelinen EL, Fourie B, Gozuacik D, Hong W, Hotamisligi G, Jäättelä M, Jo EK, Johansen T, Juhász G, Kimchi A, Ktistakis N, Kroemer G, MIzushima N, Münz C, Reggiori F, Rubinsztein D, Ryan K, Schroder K, Simonsen A, Tooze S, Vaccaro M, Yoshimori T, Yu L, Zhang H, Klionsky DJ

Recently, NIH has funded a center for autophagy research named the Autophagy, Inflammation, and Metabolism (AIM) Center of Biomedical Research Excellence, located at the University of New Mexico Health Science Center (UNM HSC), with aspirations to promote autophagy research locally, nationally, and internationally. The center has 3 major missions: (i) to support junior faculty in their endeavors to develop investigations in this area and obtain independent funding; (ii) to develop and provide technological platforms to advance autophagy research with emphasis on cellular approaches for high quality reproducible research; and (iii) to foster international collaborations through the formation of an International Council of Affiliate Members and through hosting national and international workshops and symposia. Scientifically, the AIM center is focused on autophagy and its intersections with other processes, with emphasis on both fundamental discoveries and applied translational research.

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Autophagy, , 1554-8635, , 2018

PMID: 29938597