基质硬度/巨噬细胞协同调控肝细胞行为及肝纤维化

Hepatic fibrosis is a chronic liver injury in which multiple cells are involved. The disease progression is accompanied by the increase of liver tissue stiffness and the infiltration of immune cells. Although studies have shown that as the initial targets of liver injury, hepatocytes can directly participate in the initiation and progression of liver fibrosis. However, at different stages of liver fibrosis, the regulation of intrahepatic physicochemical microenvironment changes on hepatocytes function and hepatic fibrosis are still unclear. To this end, this project intends to build a cell culture model to explore the synergistic effect of substrate stiffness (physical microenvironment) and macrophages (chemical microenvironment) on hepatocyte function and hepatic fibrosis. And then verify the hypothesis that the intrahepatic physicochemical microenvironment at different stages of liver fibrosis can be involved in the process of liver fibrosis by regulating the biological functions and mechanical properties of liver cells such as apoptosis and migration. This study is helpful to further understand the important role of the intrahepatic physicochemical microenvironment in influencing the progression of hepatic fibrosis through the regulation of hepatic cell function. At the same time, it provides a new research perspective and thought for the treatment of clinical hepatic fibrosis from the perspective of mechanical biology.

肝纤维化是多细胞参与的慢性肝损伤过程，疾病进程伴随肝组织硬度的增加和免疫细胞的浸润。尽管已有研究显示肝细胞作为肝损伤的初始靶标，可直接参与肝纤维化的启动和推进过程。但不同肝纤维化阶段，肝内物理化学微环境变化对肝细胞功能的调控及其参与纤维化的机制仍不清楚。为此，本课题拟构建细胞培养模型，探讨基质硬度（物理微环境）/巨噬细胞（化学微环境）协同作用对肝细胞功能的影响及参与肝纤维化的机制。进而在体内外水平，验证本项目提出的“肝纤维化不同阶段的肝内理化微环境，可通过调控肝细胞凋亡、迁移等生物学行为和力学特性进而参与肝纤维化进程”假说。本研究有助于深入认识肝内理化微环境通过肝细胞功能调节，影响肝纤维化疾病进程的重要地位；同时从力学生物学的角度为临床肝纤维化的治疗提供新的研究视角和思路。

肝纤维化是多细胞参与的慢性肝损伤过程，疾病进程伴随肝组织硬度的增加和免疫细胞的浸润。尽管已有研究显示肝内巨噬细胞是肝纤维化炎症微环境的最主要贡献者，可直接参与肝纤维化进程。但不同肝纤维化阶段，肝内物理微环境变化对肝细胞和肝内巨噬细胞功能的调控及其参与肝纤维化的机制仍不清楚。为此，本课题探讨不同基质硬度对肝细胞和肝内巨噬细胞的调控及其协同作用对肝纤维化的影响。本课题研究发现2D/3D Stiff基质可能通过调控肝细胞骨架重排、极化、下调肝细胞功能标志蛋白表达、上调肝细胞凋亡和迁移，参与肝纤维化疾病进程，并初步证实Integrin-β1和β-catenin所介导的细胞-基质间连接和细胞-细胞间连接的平衡互作，参与了不同基质硬度对肝细胞力学特性变化的调节。进一步的研究发现，本研究硬度范围内，Soft组基质调节巨噬细胞向抗炎和促组织修复表型转化，而Stiff组细胞则调节巨噬细胞向促炎表型进行转化。回输Soft基质刺激后的巨噬细胞至纤维化小鼠体内，可在细胞回输后的早期，通过提高肝内Ly-6Clow亚群巨噬细胞比例，增加肝内抗炎促修复表型巨噬细胞数目；上调肝内巨噬细胞基质金属蛋白酶表达水平及促肝内肝星状细胞凋亡，改善肝内微环境，减少肝内胶原沉积，进而缓解肝纤维化。本文的研究有助于认识基于肝纤维化病理硬度的体外基质硬度，影响肝细胞和肝内巨噬细胞功能进而参与肝纤维化的重要地位。同时从力学-免疫学的角度为临床肝纤维化的治疗提供新的研究视角和思路。