Roquin proteins are required to preclude spontaneous T cell activation and aberrant T follicular helper (Tfh) or T helper 17 (Th17) differentiation. Here, we show that deletion of Roquin encoding alleles in regulatory T cells (Tregs) also caused the activation of conventional T cells. These Tregs exhibited a follicular Treg phenotype, CD25 downregulation and could not protect from colitis. Mechanistically, Roquin was required for full expression and activity of Pten and Foxo1, two essential signaling molecules in Tregs and effector T cells. Roquin upregulated Pten by interfering with miR-17~92 binding to an overlapping cis-element in the Pten 3' UTR and downregulated the Foxo1-specific E3 ubiquitin ligase Itch. Loss of Roquin enhanced mTOR signaling and global protein synthesis, while inhibition of PI3K or mTOR in Roquin-deficient CD4+ T cells corrected increased Tfh and Th17 differentiation. Thereby, the control of PI3K-mTOR signaling by Roquin prevents autoimmunity through T cell-intrinsic and Treg-mediated regulation. SOURCE: Joao,C,Guimaraes (joaoguima@gmail.com) -  University of Basel

Pluto Bioinformatics

GSE86110: Roquin suppresses PI3K-mTOR signaling to control T cell differentiation and Treg effector function