S1PR1 and cholestasis: However, although the expression of S1P and S1P1 and S1P3 is reported to play a role in promoting fibrosis in liver fibrosis models of BDL and CCl4 stimulation (Yang et al., 2013; Wang et al., 2015), S1P1 was associated with the formation of angiogenesis and granulation tissue in another report (Yanagida and Hla, 2016), and in a study of chronic injury and cholestasis in mice, S1P1 was found to be highly expressed in vascular endothelial cells and then reduce fibrosis by stimulating hepatic regeneration (Ding et al., 2016).