IL-2R signaling is essential for regulatory T cell (Treg) function. However, the precise contribution for IL-2 during Treg thymic development, peripheral homeostasis, and lineage stability remains unclear. Here we show that IL-2R signaling is essential for thymic Tregs at an early step for expansion/survival and a later step for functional maturation. Using selective deletion of CD25 in peripheral Tregs, we also find that IL-2R signaling was absolutely essential for their persistence whereas Treg lineage stability was IL-2-independent. CD25 knockout peripheral Tregs showed increased apoptosis, oxidative stress, signs of mitochondrial dysfunction, and reduced transcription of key enzymes of lipid and cholesterol biosynthetic pathways. A divergent IL-2 transcriptional signature was noted for thymic Tregs versus peripheral Tregs. These data indicate that IL-2R signaling in the thymus and the periphery leads to distinctive effects on Treg function, where peripheral Treg survival depends on a non-conventional mechanism of metabolic regulation. SOURCE: Thomas Malek (tmalek@med.miami.edu) -  University of Miami

Pluto Bioinformatics

GSE121883: Essential and non-overlapping IL-2R-dependent signaling for thymic development and peripheral homeostasis of regulatory T cells