FOS and colitis: Intracolonic administration of the TRPV4 agonists (4alpha-phorbol-12,13-didecanoate or GSK1016790A) in mice activated NF-κB and activator protein 1 (AP-1) signaling pathway, resulting in exacerbated DSS-induced colitis and even transiently increased the paracellular permeability of epithelium and blood vessel, while TRPV4-knockout mice conferred a strong resistance to the colitis (73, 81).