Fig. 2

Gut microbiome-associated SCFAs shape the homeostatic host–microbiome interface. SCFAs foster a hypoxic microenvironment by activating PPAR-γ and undermining the pH homeostasis of pathogens to inhibit pathogen growth. SCFAs also signal through GPRs (such as GPR43) to secrete IL-18 and AMP, contributing to enhanced intestinal barrier function