活体肝脏移植术后干预wip1/mTOR通路预防肝脏再生中NAFLD的机制研究

Nonalcoholic fatty liver disease(NAFLD) is one of the risk factors impairing liver regeneration post living donor liver transplantation(LDLT). Dyslipidemia is associated with NAFLD. Mammalian target of rapamycin (mTOR) signal pathway plays key role in lipid metabolisms. We found the expression of a phosphatase named wild type 53 induced phosphatase 1 (wip1) is associated with lipid metabolisms. And wip1 delay liver regeneration through inhibiting mTOR. We hypothesized that wip1/mTOR may play key role in liver regeneration and lipid metabolisms and NAFLD post LDLT. Based on our previous study, we will analyze clinical parameters of patients recieved LDLT retrospectively. We will determine the expression of wip1, mTOR and score of the steatosis of liver tissue and investigate the association of wip1/mTOR and NAFLD. We will further detect the expression of wip1, mTOR, S6K, total triglyceride and total cholesterol after inhibiting wip1/mTOR signal pathway in mice hepatocytes, liver tissues of mice underwent partial hepatectomy and liver tissues of rat recieving liver transplantation. We will investigate the underlying mechanisms of wip1/mTOR regulating liver regeneration and lipid metabolisms and its role in NAFLD. The results of the project may shed light on wip1/mTOR as therapeutic target of NAFLD. And the project will provide theoretical basis and laboratory evidence for using wip1/mTOR as target to prompt liver regeneration in order to improve the efficacy of living donor liver transplantation.

活体肝脏移植（LDLT）后非酒精性脂肪肝病（NAFLD）是延缓肝脏再生、影响肝移植效果的危险因素，NAFLD与脂肪代谢障碍相关；mTOR通路在脂肪代谢中起重要作用。我们发现wip1表达与脂肪代谢相关，且wip1抑制mTOR延缓肝脏再生。推测wip1/mTOR在NAFLD发病中起重要作用。在前期研究基础上，我们拟回顾性分析活体肝脏移植患者的临床资料，检测肝活检组织脂肪变性程度以及wip1、mTOR蛋白，阐明wip1/mTOR与NAFLD相关性；利用小鼠肝细胞、小鼠肝部分切除以及大鼠肝移植模型，干预wip1/mTOR通路，检测wip1、mTOR、S6K以及甘油三酯、胆固醇水平，研究wip1/mTOR通路在肝移植后肝再生和脂肪代谢以及NAFLD中的作用和分子机制。探索干预wip1/mTOR预防活体肝移植术后NAFLD，促进肝脏再生的可行性，为临床预防NAFLD，提高肝移植效果提供新思路。

肝脏再生过程中脂质代谢是关键的分子生物学变化，脂肪代谢的改变会影响肝脏再生。项目前期研究发现肝脏再生过程早期脂质沉积于肝细胞，促进脂质沉积于肝脏细胞能够促进肝脏再生；项目组针对肝脏再生过程中脂肪代谢变化及其调控机制进行探索，研究发现：1.小鼠肝部分切除后，TSh水平显著升高，上调TSH能够促进肝细胞内脂滴沉积，进而促进肝脏细胞增殖，高通量测序结果显示，上调TSH能够诱导ADRP表达，进而促进肝细胞内脂滴形成。2.高脂饮食小鼠肝脏细胞内Nur77蛋白表达显著升高，体外实验结果显示油酸诱导Nur77表达，AMPK通路蛋白水平升高，干预Nur77与LKB1结合能够下调AMPK信号通路活化，进而抑制肝细胞内脂肪沉积。