small RNA-Seq of miR-181 deficient Treg cells

The interdependence of selective cues during development of regulatory T (Treg) cells in the thymus and their suppressive function remains incompletely understood. Here we analyzed this interdependence by taking advantage of highly dynamic changes of miR-181a/b-1 during late T-cell development with very high levels of expression during thymocyte selection followed by massive downregulation in the periphery. Loss of miR-181a/b-1 resulted in inefficient de novo generation of Treg cells in the thymus, but simultaneiously permitted homeostatic expansion in the periphery in the absence of competition. Modulation of T-cell receptor (TCR) signal strength in vivo indicated that miR-181a/b-1 controlled Treg cell formation via establishing adequate signaling thresholds. Unexpectedly, miR-181a/b-1-deficient Treg cells displayed elevated suppressive capacity in vivo, in line with elevated levels of CTLA-4 protein, but not mRNA, in thymic and peripheral Treg cells. Therefore, we propose that intrathymic miR-181a/b-1 controls development of Treg cells and imposes a developmental legacy on their peripheral function. miR-181a-1/b-1 deficient Treg cells were sorted and sequenced for small RNA. Wild type Treg cells were used as a control. Results were then analyzed for differential expression of micro RNAs. Three biological replicates were analyzed