From:  Nutrient-driven immunometabolism in metabolic disease

 Gut microbiota-derived metabolites: sources and immunometabolism roles.

Microbial metabolitePrimary dietary precursorsMajor receptors/TargetsImmunometabolism effects and relevance
SCAFs (butyrate)Dietary fiber, resistant starch [132]GPR109A, HDAC inhibition [122]Fuels colonocytes; promotes colonic Tregs; enhances gut barrier integrity [122].
SCAFs (propionate, acetate)Dietary fiber, resistant starch [132]GPR43/GPR41 [133]Systemic immune regulation inhibits inflammatory cytokine production [134].
Tryptophan derivatives (indole, IAld)Dietary tryptophan [121]AhR [135]Modulates ILC3, Th17, and Treg balance; maintains mucosal immunity [126].
Secondary bile acids (e.g., LCA, DCA)Primary bile acids + bacterial enzymes [136]FXR, TGR5Anti-inflammatory in the liver; regulates systemic metabolism and immunity.

AhR: aryl hydrocarbon receptor; DCA: deoxycholic acid; FXR: farnesoid X receptor; GPR: G protein-coupled receptor; HDAC: histone deacetylase; LCA: lithocholic acid; SCFAs: short-chain fatty acids; TGR: Takeda G protein-coupled receptor 5; Treg: regulatory T cell.