S1PR2活化PERK调控EMT介导脑死亡供肝肝移植术后缺血型胆道上皮损伤的机制研究

Brain injury is the main cause for brain death. Ischemic-type biliary injury (ITBI) is a common complication after liver transplantation with graft donation after brain death. The underlying mechanism of ITBI remains to be determined. It was reported that epithelial-mesenchymal transition (EMT) of intrahepatic biliary epithelial cells is a key molecular basis for the development of ITBI. In preliminary studies in liver transplantation with graft donation after brain death, we found that the expression of S1PR2, PERK, Twist and fibroblast-specific protein1 (FSP-1), was activated in intrahepatic biliary epithelial cells. In additional , inhibition of S1PR2 significantly reduced the degree of ITBI and the expression of PERK,TWIST and FSP-1.These evidences led us to hypothesize that EMT mediated by a signaling pathway consisting of S1PR2,PERK and FSP-1 may involve in regulation of the development of ITBI. In this proposal, we seek to further investigate S1PR2-PERK-EMT signaling pathway. In collaboration with monitoring of serum biomarkers of biliary injury and observation of morphological alternation of intrahepatic biliary epithelial cells and observation of the expression of S1PR2 and FSP-1 , we will elucidate the role and molecular mechanism of this pathway in regulation of ITBI development following liver transplantation with graft donation after brain death. We will employ complementary approaches that include gene transfection, small hairpin RNA, co-immunoprecipitation, confocal microscopy, combined with primary culture of biliary epithelial cells, rat models of liver transplantation. This study will provide theoretical basis to explore mechanism-driven approaches for future prevention and treatment of ITBI following liver transplantation.

颅脑损伤是导致脑死亡的重要原因。缺血型胆道上皮损伤（ITBI）是脑死亡供肝肝移植术后的常见胆道并发症，其机制尚待阐明。研究发现EMT在肝移植术后ITBI中起重要作用。前期我们发现：脑死亡大鼠供肝肝移植术后ITBI的胆道上皮细胞中S1PR2、PERK、Twist及FSP-1表达升高，抑制S1PR2后显著减轻脑死亡大鼠供肝肝移植术后ITBI，并降低PERK、Twist及FSP-1等表达。据此推测可能存在S1PR2--PERK--EMT信号通路介导脑死亡供肝肝移植术后ITBI的发生。本研究拟从大鼠脑死亡模型，原代胆管上皮细胞，大鼠肝移植模型等方面利用基因沉默、免疫共沉淀、激光共聚焦等技术，检测S1PR2、FSP-1等相关信号分子的改变及其胆道损伤的血清学、形态学等指标变化。可望阐明S1PR2调控PERK促进EMT的分子机制，为减轻脑死亡供肝肝移植术后ITBI的发生提供理论基础和潜在的治疗靶点。

缺血型胆道上皮损伤（ITBI）是脑死亡供肝肝移植术后的常见胆道并发症。 肝脏移植术后胆道并发症由于其高发病率，早期诊断困难及预后不良的特点，一直是移植界关注的焦点。通过临床研究发现：脑死亡供体供肝移植术后缺血型胆道损伤的上皮细胞中 S1PR2 及 PERK 表达增加。脑死亡供肝移植后缺血型胆道损伤中，S1PR2 表达增加的胆道上皮细胞中，PERK 表达增加; 给予 JTE-013 抑制S1PR2 后，能减轻脑死亡供肝移植后缺血型胆道损伤并且发现 PERK 表达降低。我们发现S1PR2通过活化PERK从而介导缺血型胆道上皮损伤。为减轻脑死亡供肝肝移植术后ITBI的发生提供理论基础和潜在的治疗靶点。此外，缺血再灌注损伤是影响肝移植术后移植物功能障碍以及胆道损伤的重要因素，发现了STEAP3是影响肝脏缺血再灌注损伤的靶点，为移植供肝以及胆道损伤的保护提供治疗方向。