肾移植患者中环孢素导致肝损伤的个体差异及其机制研究

Cyclosporine is a kind of effective immunosuppressive agents, commonly used in organ transplant recipients. Liver injury is common adverse reaction of cyclosporine which is the main reason for withdrawal or even death. Our previous studies showed that certain genetic polymorphisms of CYP3A4, CYP3A5, MRP2 were associated with liver damage caused by cyclosporine. Therefore, we hypothesized that CYP3A4\CYP3A5\MRP2\PXR pathway plays a critical role in cyclosporine induced liver injury. Firstly, clinical data were collected to identify risk factors for cyclosporine induced liver injury in renal transplant recipients. Secondly, according to the metabolism of cyclosporine, genes of CYP3A4/ CYP3A5/MRP2/PXR pathway and the SNPs of these genes were selected for this study. The associated SNPs of the cyclosporine induced liver injury were screened by case-control method. Furthermore, the functions of associated SNPs of CYP3A4, CYP3A5, ABCC2, NR1I2 were investigated by molecular and cell biology techniques in vitro, especially the gene-gene interactions of these genes influence on liver injury. In this study, the variations of genes in CYP3A4/CYP3A5/MRP2/PXR pathway and their mechanisms associated with cyclosporine induced liver injury will be illuminated, which can reduce the incidence of liver injury and will be importance of personalized medicine of cyclosporine.

环孢素是器官移植受者最常用的免疫抑制剂之一，肝脏损伤是环孢素常见的不良反应，严重者可至撤药甚至死亡。我们前期研究提示CYP3A4、CYP3A5、MRP2某些位点的基因多态性可能和环孢素导致的肝损伤相关。因此，我们推测CYP3A4\CYP3A5\MRP2\PXR代谢通路在环孢素导致的肝损伤中起关键作用。本课题首先拟研究肾移植术后环孢素导致肝损伤的危险因素。其次，选择CYP3A4\CYP3A5\MRP2\PXR通路上基因为研究对象，采用病例对照的方法筛选该通路中与肝损伤相关联的SNPs。最后通过体外分子和细胞生物学实验，分别研究这些基因以及相关联SNPs功能，尤其是基因-基因交互作用对环孢素导致肝损伤的影响。本研究将系统阐明CYP3A4\CYP3A5\MRP2\PXR代谢通路关键基因变异在CsA导致肝损伤中的作用及其分子机制，对于减少肝损伤发生及实现环孢素个体化用药具有重要意义。

环孢素（CsA）是临床常用的免疫抑制剂，广泛用于器官移植后抗免疫排斥反应。肝损伤是环孢素常见的不良反应之一，然而其发生机制尚未完全阐明。本项目从CYP3A4\CYP3A5\MRP2\PXR代谢通路探究环孢素导致的肝损伤的个体差异及发生机制。本项目对探究环孢素导致的肝损伤的危险因素，减少肝损伤的发生及实现环孢素个体化用药具有重要意义。. 在肾移植术后环孢素导致肝损伤的危险因素方面，通过采用病例对照的方法筛选该通路中与肝损伤相关联的SNPs，结果发现，CYP3A4、ABCB11、NR1I2基因多态性与CsA所致的肝损伤相关，其中CYP3A4 rs3735451、ABCB11 rs7577650、NR1I2 rs7643645和NR1I2 rs12488820位点与CsA导致肝损伤发病密切相关，是CsA导致肝损伤发病的危险因素。. 我们采用人肝微粒体孵育实验，用于CYP3A5 rs776746的功能研究。结果发现CYP3A5表达型（CYP3A5*1*1/CYP3A5*1*3）酶活性显著高于CYP3A5非表达型（CYP3A5*3*3）。. 通过体外分子和细胞生物学实验研究表明，CsA通过激活PXR通路抑制代谢酶CYP3A4、CYP3A5及转运体MRP2转录水平和蛋白水平的表达。CYP3A4、CYP3A5、MRP2、PXR的低表达加重CsA所致的细胞毒性和损伤。. 上述结果提示，CsA导致肝损伤与CYP3A4\CYP3A5\MRP2\PXR代谢通路相关，CYP3A4\CYP3A5\MRP2\PXR通路可能是CsA致肝损伤的靶点之一，对探讨CsA致肝损伤的危险因素及防治提供新思路。