microRNAs controlling T cells - are we ready for the next step?
Our group is interested in posttranscriptional mechanisms of gene regulation which are operational in lymphocytes. We focus on T cell subsets which are important for immune regulation and we have a particular interest in microRNA (miRNA)-mediated gene regulation. We previously demonstrated the importance of miRNAs for regulatory T cells (Treg) and follicular helper T cells (TFH) biology. Specifically, we demonstrated that the miR-17-92 cluster is induced in a CD28-dependent manner after T cell activation. We found that miR-17-92 is largely dispensable for conventional and regulatory T cells under homeostatic conditions. However, during an immune response Treg and TFH depend on miR-17-92. I will discuss our current understanding of the molecular program guided by miR-17-92 during TFH differentiation.
However, despite major advances in miRNA research the analysis of target genes which are regulated by individual miRNAs remains challenging. It can be very difficult to demonstrate that a particular miRNA not only represses a gene or a set of genes but to what degree this repression is functionally relevant. I will therefore discuss current limitations and possible ways to overcome these obstacles.