基底硬度与TGF-β1 协同作用对肝纤维化进程影响的机制研究

In the process of hepatic fibrosis, there were huge of hepatic cells died and reborn, and formed false floccules structure. This project is to explore the mechanical-chemical synergistic effects of substrate rigidity and the cytokine TGF-β1 on the phenotypic transformation of hepatocytes, by establishing an in vitro cell culture model with an physiologically and pathologically relevant as well as controllable substrate rigidity. The key factor of fibrosis was orgnized reconstruction of cells. This project has captured the balance of interaction between cells and cells, cells and substrate in the process of orgnized reconstruction, and it has also brought the e-cadherin system of mediating cell-cell adhesion and the intergrin system of mediating cell-substrate adhesion into one framework, to research through what methods and michanics the substrate rigidity enhanced the effects of TGF-β1 influences the adjusting imbalance of two adhesion systems of hepatic cells. Cytoskeleton network integrates two Adhesion systems ( cadherin and integrin) with TGF-β signaling to be one entity of structure and function, we think the antagonism of the two systems rely on modulation of cytoskeleton, according to influence the cytoskeleton structure, tension and spread, the substrate rigidity's variation could possibly regulate activity and distribution of biological molecule, then influence the cellular phenotype and function. This research mentality could provide new vision to deeply study hepatic fibrosis lesions forming process mechanism.

肝纤维化过程中肝细胞大量死亡、再生，并形成假小叶结构。本立项通过建立与肝组织生理和病理硬度相当的体外培养模型，探索基底硬度与致纤维化因子TGF-β1协同作用对肝细胞表型改变的影响。纤维化病变的中心环节是细胞的组织化重构，本立项抓住组织化重构过程中细胞与细胞，以及细胞与基底相互作用的平衡调节这一关键，并把介导细胞-细胞间粘附的E-钙粘素系统和介导细胞-基底粘附的整合素系统纳入统一框架综合考查，研究基底硬度通过什么途径及机制增强了TGF-β1对肝细胞两大粘附系统平衡调节失衡的影响。细胞骨架网络把两大粘附系统和TGF-β信号通路整合为一结构功能整体，我们认为钙粘素和整合素两大粘附系统的拮抗调节对骨架结构调整存在依赖，而基底硬度变化可能正是通过影响骨架结构及其张力分布来调控这些生物大分子的活性和定位，从而影响细胞表型和功能的，这一研究思路对深入揭示肝纤维化病变形成的过程机制提供了新视角。

肝纤维化是慢性肝脏病变晚期的组织学变化，是一种在创伤因子持续作用下渐变的病理过程，主要以胞外基质的增加为特征，同时伴有肝细胞的大量死亡、再生，并导致肝脏结构紊乱。基于上一个基金的研究成果，发现基底硬度可以通过改变肌动蛋白骨架的重塑，来改变肝细胞表型，对其机制并未深入探究，本项目通过建立与肝组织生理、病理硬度相当的、生物相容性良好的体外培养模型，重点研究不同硬度基底作用下，肝细胞的力生物学基础。考察不同基底硬度刺激，对肝细胞细胞行为影响，解析基底硬度的作用机制；考察不同基底硬度对肝细胞力学行为的影响并分析其细胞机制；研究不同基底硬度通过细胞-细胞黏附和细胞-基底黏附两大黏附系统，对肝细胞行为产生影响的作用机制；体内动物水平，验证组织力学性能变化与两大黏附系统间相互关系。本项目的研究，试图探寻肝纤维化发生发展的细胞力学解释，为肝纤维化病变机制和治疗方式研究及提供了新的思路。