The roles of bile acid signaling and its interactions with a lipid mediator

Abstract

Recent advances in molecular biology have revealed existence of specific receptors for bile acids, and the roles of bile acids as signaling molecules have attracted increasing attention. It has been revealed that conjugated bile acids specifically activate sphingosine-1-phosphate (S1P) receptor type 2 (S1PR2). The activation of S1PR2 by conjugated bile acids stimulates SphK2, one of two sphingosine kinases which produces S1P. It has been reported that conjugated bile acids and S1P signaling via S1PR2 and SphK2 regulate lipid and glucose metabolism in the liver, and promote progression of cholangiocellular carcinoma. These findings suggest that bile acids and S1P signaling associate with variety of pathophysiology. Here, we introduce the roles of bile acid signaling and its interactions with S1P signaling via S1PR2 and SphK2 in the pathophysiology of hepatobiliary diseases.