YAP抑制剂维替泊芬通过自噬效应阻缓创伤性关节炎的机制研究

The alteration of mechanotransduction is significant for the balance of degeneration or regeneration for traumatic cartilage tissues. It is very important to elucidate the mechanism of mechanotransduction in articular chondrocytes or extracellular matrix for treating posttraumatic osteoarthritis (PTOA). Our former research results showed that creating a stress loading matrix environment by hydro collagen scaffold in articular chondrocytes promotes cartilage self-repair by migration and differentiation of cartilage-derived mesenchymal stem cells. But the mechanism is not clear yet. This process is probably regulated by YAP/TAZ signal pathway. Our other former studies showed that autophagy effect was over activated in chondrocyte of PTOA. And this effect may be induced by YAP/TAZ signal pathway. In this study, we are going to mimic the traumatic articular dynamic mechanical change environment and clarify the mechanism of degeneration or regeneration of chondrocytes regulated by YAP/TAZ signal pathway. The further study is focus on explaining the molecular mechanism of YAP/TAZ signaling pathways mediating effect of autophagy in chondrocytes. Finally, we are going to use the YAP inhibitor verteporfin combining with chitosan/polyacrylamide hydrogel to treat the PTOA animal models and analyze the therapeutic effect. The study of mechanotransdution and YAP/TAZ and autophagy role in chondrocytes shall provide new theoretical and practical basis for treatment of PTOA.

生物力学环境对关节创伤后软骨再生/退变平衡有重要影响，阐明关节软骨细胞及细胞外基质力学信号转导过程对于治疗创伤性关节炎十分关键。申请者在前期研究中发现关节创伤后软骨衍生间充质干细胞可以在水凝胶原膜的应力载荷诱导下向软骨表面迁移并分化为软骨细胞进行关节软骨的修复。然而具体机制未清，可能由YAP/TAZ信号通路调控。进一步发现，自噬在创伤性关节炎软骨中过度激活诱发软骨病变，该变化可能由YAP/TAZ信号介导。本项目拟在此基础上，进一步阐明动态应力变化通过YAP/TAZ信号系统对软骨细胞的调节作用。并探讨YAP/TAZ信号通路介导自噬效应导致软骨细胞变化的分子机制。最后应用YAP药物抑制剂维替泊芬联合壳聚糖/聚丙烯酰胺水凝胶治疗创伤性关节炎动物模型，分析该治疗手段的治疗效果。深入研究YAP/TAZ通路在软骨细胞力学信号转导中的作用与机制，可为创伤性关节炎疾病的有效治疗提供新的理论基础与应用依据。

生物力学环境对关节创伤后软骨再生/退变平衡有重要影响，阐明关节软骨细胞及细胞外基质力学信号转导过程对于治疗创伤性关节炎十分关键。我们在前期研究中发现关节创伤后软骨衍生间充质干细胞可以在水凝胶原膜的应力载荷诱导下向软骨表面迁移并分化为软骨细胞进行关节软骨的修复，然而具体机制未清。.在此次资助研究中，我们研究发现：（1）在创伤退变后的软骨下组织内骨髓间充质干细胞的特性会发生变化，产生出“病理干细胞”，该细胞具有干细胞自我更新和分化的特性，呈现病理性更新和分化并导致疾病产生，抑制关键的Wnt信号通路可以部分恢复干细胞分化特性，促进组织再生。（2）进一步研究揭示，在应力失衡和创伤环境下，早期细胞可以启动自噬而达到保护自身的目的，而如果力学微环境失衡持续存在，晚期则会抑制自噬导致细胞的病理性变化，该病理变化效应由YAP/TAZ信号通路调控。（3）最后，我们体内小鼠动物实验的研究证明，应力失衡诱发的PTOA可以被自噬激活所抑制，口服西罗莫司的PTOA小鼠，关节腔中软骨衰老细胞特异性蛋白SA-β-gal表达明显减低。基于以上分析，我们推测关节创伤后，在应力持续失衡下，YAP/TAZ活性改变，发生自噬性降解，晚期抑制自噬，降低新陈代谢，导致软骨细胞衰老。自噬在创伤性关节炎中“应力失衡-衰老”效应中具有明确功能，可能是这一生物学行为的核心调控元件，这一发现具有原创性。