Patrick M. Smith1, Michael R. Howitt1, Nicolai Paniko et al[31]discovered that bacterial fermentation products derived from gut microbiota – short-chain fatty acids, can regulate the size and function of the colonic Treg pool through G protein-coupled receptor 43(GPCR43) mediation expressed in the colon, and protect mice from colitis in a Free fatty acid receptor 2 (Ffar2)-dependent manner. This evidence concerns the gene FFAR2 and colitis.