Role of RORgt+ (note: g: is gamma symbol) lymphocytes in Gut Tissue Homeostasis

Project Summary/Abstract: ILC3s, gdT17 and Th17 cells share common features, e.g., expressing the master transcription factor RORgt and the effector cytokines IL-17A, IL-17F and IL-22, and perform distinct immune functions under different environment context. Our preliminary data suggest that RORgt+ cell-intrinsic deletion of Tfam in Tfamfl/flRorc- cre mice affected RORgt+ gdT17 cells and ILC3s in vivo maintenance and led to small intestinal tissue remodeling via a tuft cell–ILC2 circuit. An emerging concept of mitochondrial control of immunity beyond ATP generation has recently been proposed. Based on the premise and our preliminary data, we hypothesize that that Tfam-mediated mitochondrial respiration in gdT17 cells and ILC3s is pivotal for gdT17/ILC3 cell homeostasis and regulation of small intestine tissue remodeling/metabolic changes and immunity/inflammation. Specifically, we will investigate 1) the role of Tfam in gdT17 and ILC3 lymphocyte maintenance, 2) the role of Tfam in gdT17 cells and/or ILC3s in regulating tuft cell-ILC2 circuit and small intestine tissue remodeling, and 3) the role of Tfam in gdT17 cells and/or ILC3s in regulation of microbiome and small intestinal immunity and inflammation. These experiments will offer an opportunity to elucidate Tfam- mediated mitochondrial respiration in RORgt+ lymphocytes in the small intestine under the steady state and during infection/immunity. Our study will provide novel cellular and molecular insights into the maintenance and function of gdT17 cells and ILC3s regulated by Tfam. Understanding the mechanisms underlying the requirement of Tfam for RORgt+ cells in regulation of small intestine tissue remodeling and immunity may represent a new paradigm for human disease treatment and/or prevention.