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The Role of Sphingosine 1-phosphate Receptor 2 in Bile-Acid-Induced Cholangiocyte Proliferation and Cholestasis-Induced Liver Injury in Mice

Yongqing Wang, Hiroaki Aoki, Jing Yang, Kesong Peng, Runping Liu, Xiaojiaoyang Li, Xiaoyan Qiang, Lixin Sun, Emily C Gurley, Guanhua Lai, Luyong Zhang, Guang Liang, Masayuki Nagahashi, Kazuaki Takabe, William M Pandak, etc.

Hepatology. 2017 Jun;65(6):2005-2018.

PMID: 28120434

Abstract:

Bile duct obstruction is a potent stimulus for cholangiocyte proliferation, especially for large cholangiocytes. Our previous studies reported that conjugated bile acids (CBAs) activate the protein kinase B (AKT) and extracellular signal-regulated kinase 1 and 2 (ERK1/2) signaling pathways through sphingosine 1-phosphate receptor (S1PR) 2 in hepatocytes and cholangiocarcinoma cells. It also has been reported that taurocholate (TCA) promotes large cholangiocyte proliferation and protects cholangiocytes from bile duct ligation (BDL)-induced apoptosis. However, the role of S1PR2 in bile-acid-mediated cholangiocyte proliferation and cholestatic liver injury has not been elucidated. Here, we report that S1PR2 is the predominant S1PR expressed in cholangiocytes. Both TCA- and sphingosine-1-phosphate (S1P)-induced activation of ERK1/2 and AKT were inhibited by JTE-013, a specific antagonist of S1PR2, in cholangiocytes. In addition, TCA- and S1P-induced cell proliferation and migration were inhibited by JTE-013 and a specific short hairpin RNA of S1PR2, as well as chemical inhibitors of ERK1/2 and AKT in mouse cholangiocytes. In BDL mice, expression of S1PR2 was up-regulated in whole liver and cholangiocytes. S1PR2 deficiency significantly reduced BDL-induced cholangiocyte proliferation and cholestatic injury, as indicated by significant reductions in inflammation and liver fibrosis in S1PR2 knockout mice. Treatment of BDL mice with JTE-013 significantly reduced total bile acid levels in serum and cholestatic liver injury.
Conclusion:
This study suggests that CBA-induced activation of S1PR2-mediated signaling pathways plays a critical role in obstructive cholestasis and may represent a novel therapeutic target for cholestatic liver diseases. (Hepatology 2017;65:2005-2018).

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP383150412 JTE-013 JTE-013 383150-41-2 Price
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