Table 1.

SCFA G-Protein Coupled Receptors^18,27–35

GPCR	Tissue/Cell Expression	Signaling	Ligands
GPR41, FFAR3	Adipose tissue, peripheral blood mononuclear cells (PBMC), pancreas, spleen and placenta monocytes, neutrophils, and monocyte-derived dendritic cells	Gαi/G0 Β-gustducin	Acetate, propionate, butyrate, formate, pentanoate
GPR43, FFAR2	Intestinal epithelium, monocytes, neutrophils, PBMCs, B and T lymphocytes, T regulatory cells, and colonic myeloid cells	Gαi/G0 and Gαq/11 Β-arrestin-2	Acetate, propionate, butyrate, pentanoate, hexanoate, formate
GPR109A, HCAR2, NIACR1	Colon, ileum, jejunum, duodenum; adipose tissue, lung, spleen, monocytes, monocyte-derived dendritic cells, dendritic cells, and macrophages	Gαi/G0 Β-arrestin-1	Butyrate, β-hydroxybutyrate, niacin

Abbreviations: GPR, G-protein coupled receptor; FFAR2, free fatty acid receptor 2; FFAR3, free fatty acid receptor 3; HCAR2, hydroxycarboxylic acid receptor 2; NIACR1, nicotinic acid receptor.