FFAR2 and infection: GPR41-/- and GPR43-/- mice have a weaker immunity to respond to inflammation and infection induced by ethanol, 2,4,6 trinitrobenzene sulfonic acid (TNBS), or Citrobacter rodentium, as well as a slower clearance of bacteria compared to normal mice, and GPR41 and GPR43 regulate the production of chemokines and cytokines in epithelial cells through the activation of the extracellular protein kinase (ERK1/2) and p38 mitogen-activated protein kinase (MAPK) signaling pathways that regulate the immune-inflammatory process [84].