Metabolites from commensal microbes contribute to establish the immunity comprising RORγt+ ILC3-Treg axis in ileum Peyer’s patch

Innate lymphoid cells (ILCs) are the most recently characterized cell populations by lymphoid cell morphology and do not express both somatically rearranged antigen receptors and cell lineage markers. The ILC family is categorized into three groups according to the characteristics of cytokine secretion and transcription factor expression. Among them, ILC3 population is heterogeneous and represents all RORγt⁺ ILC subtypes. Although ILCs are small population in tissue, their strategic location at mucosal barriers enables them to regulate mucosal immune responses. Recent studies suggest the ILCs as crucial responder to metabolic stress although it was poorly understood. We have been interested in the association between Peyer’ patch ILCs and butyrate, one of the metabolites from commensal microbiota, because it was reported as a modulator for Th17 and Treg cells in lamina propria. We monitored the level of butyrate and distribution of ILCs and Treg cells in ileum Peyer’s patch and suggest that butyrate can contribute to maintain mucosal homeostasis through regulation of RORγt⁺ ILC3-Treg axis in mucosal immunity. (S.-H. Kim, Y. N. Kim, H.-Y. Lee, and J. Park were supported by BK21 Plus program in the Department of Bioactive Material Sciences. This study was supported by the Basic Science Research Program, NRF-2014R1A1A3051207 (S.-H. Kim) and NRF-2013R1A2A2A01014459 (Y.-S. Jang).