Table 1.

Bacterial metabolites and their molecular targets in the host

Metabolites	Targets
Short-chain carboxylates
Acetate, Propionate, Butyrate	GPR41, GPR43, HDACs
Butyrate	GPR109A, HDACs
Lactate	GPR81, NDRG3
Succinate	GPR91, TETs, PHD2
Tryptophan metabolites
Indole, Indole-3-aldehyde	AhR
Indole-3-acetic acid	AhR
Indole-3-propionic acid	PXR
Lipids and lipid metabolites
Trimethylamine	TAAR5
Deoxycholic acid, Lithocholic acid	FXR, PXR
Conjugated Linoleic and Linolenic acids	PPARα, PPARγ
10-Hydroxy-cis-12-octadecenoate	GPR40
Bacterial cell-wall components
Lipopolysaccharide	TLR4
Peptidoglycans	NOD1, NOD2
Polysaccharide A	TLR2