肝星状细胞中Hic-5调控小鼠肝再生的机制研究

In the process of liver regeneration, the activated hepatic stellate cells (HSCs) produce hepatic growth factor (HGF), Interleukin-6 (IL-6) and other factors, regulate the degradation and reconstruction of extracellular matrix (ECM) and provide a conducive environment for the proliferation of hepatocytes. Furthermore, the structure of ECM remodeling is a necessary step involving both degradation and reconstruction in the process of liver regeneration. Studies have shown that Hydrogen peroxide-inducible clone 5 (Hic-5) participates in regulating ECM under various pathological conditions. Hic-5 is also expressed in the human/mouse activated HSCs. Hic-5 deficiency alleviates liver fibrosis-induced liver injury by reducing the synthesis of collagen in mice. Therefore, Hic-5 plays an important role in regulating the HSCs involved in the degradation and reconstruction process of ECM. But there is no literature reporting on Hic-5’s regulating the liver regeneration. Our previous studies have confirmed that Hic-5 deficiency can increase the expression of Cyclin e1, Cyclin d1mRNA in the early phase after partial hepatectomy, raise the number of Ki-67 positive cells and the liver/body weight index as well as promote the liver regeneration. To further investigate the mechanism of Hic-5 in liver regeneration, our team will research on Hic-5 deficiency mice, apply the nucleic acid, protein analysis and histochemistry techniques to explore the Hic-5’s regulating MKK4/JNK signaling pathway and the degradation and reconstruction of ECM in the process of liver regeneration from the histological and cytological level. We will also describe the detailed mechanism of Hic-5 in regulating liver regeneration. Then, the human cell lines and wild type mices will be used as a research object to evaluate the feasibility of Hic-5 as a therapeutic target promoting liver regeneration. It will be provided with effective evidence for the mechanism of liver regeneration and a new therapeutic approach..

肝再生过程中HSCs产生HGF，IL-6等细胞因子和调节ECM重塑，提供有利于肝细胞增殖的环境。ECM重塑是肝再生的必要步骤。表达于活化HSCs中的Hic-5参与了不同病理条件下对ECM的调控，Hic-5 敲除时减少胶原的合成，减轻鼠肝纤维化损伤。因此，Hic-5在调节HSCs参与ECM重塑中具有重要作用。目前尚未报道Hic-5调控肝再生的研究。课题组证实：Hic-5 KO提高小鼠PH后肝组织中Cyclin e1, Cyclin d1mRNA的水平，增加Ki-67的阳性细胞数等，促进肝再生。课题组以Hic-5 KO小鼠为研究工具，应用分子生物学技术，从组织学和细胞学层面探讨Hic-5在肝再生过程中对MKK4/JNK信号通路的影响及对ECM的调控，阐述Hic-5调控肝再生的具体机制。并以人细胞和小鼠为研究对象，明确Hic-5作为促肝再生治疗靶点的可行性，为丰富肝再生的机理和治疗提供有效证据。

肝再生过程中肝星状细胞（hepatic stellate cells，HSCs）产生肝细胞生长因子（hepatocyte growth factor，HGF）、白细胞介素-6（interleukin-6，IL-6）等细胞因子和调节细胞外基质（Extracellular Matrixc，ECM）重塑，提供有利于肝细胞增殖的环境，ECM重塑是肝再生的关键步骤。课题组研究表明活化的HSCs中Hic-5参与了不同病理条件下对ECM的调控，Hic-5在调节HSCs参与ECM重塑中具有重要作用。课题组通过建立野生型（Wild type，WT）C57BL/6小鼠2/3肝切除动物模型，发现Hic-5在肝再生过程中呈动态变化，而这种动态变化与肝细胞再生之间的存在负性相关关系；建立WT和Hic-5 KO C 57BL/6小鼠的2/3肝切除模型，研究表明：Hic-5 KO提高小鼠肝切除术后肝组织中Cyclin e1、Cyclin d1 mRNA的水平，增加Ki-67阳性细胞数量，促进肝再生。同时证实了Hic-5表达于活化的人HSCs（LX-2）和WT小鼠原代HSCs中，并调控ECM的表达。利用购买获得的人LX-2和肝细胞株（HL-7702）共建体外共培养体系，应用siRNA方法沉默人HSCs中Hic-5，研究HSCs中的Hic-5对肝细胞增殖调控的影响以及具体分子机制。研究发现建立共培养体系后，各组培养液中的ALT、AST和ALB均有明显变化，且Western blot检测发现Collagen 1a1，Collagen 3a1的表达在Hic-5 siRNA人LX-2均下降，但Cyclin d1 mRNA表达升高，同时证实JNK信号通路参与Hic-5调控肝再生。综上,课题组以人HSCs（LX-2）和小鼠为研究对象，明确了Hic-5作为肝再生治疗靶点的可行性，为丰富肝再生的机理和治疗提供有效证据。