基于RBPR的肝星状细胞靶向双药递药系统治疗肝纤维化的作用与机制研究

Hepatic fibrosis is a common pathological change of various chronic liver injury, which could develop into liver cirrhosis or even liver cancer. The activation of hepatic stellate cells (HSCs) is critical in hepatic fibrosis formation and progression, and inhibiting this process can inhibit liver fibrosis effectively. On account of the activation of HSCs is regulated by many factors and interaction exists between them, the inhibition of one pathway alone could not fully suppress HSCs activation. Therefore, co-delivery of drugs which could suppressing HSCs activation through different mechanisms is an effective method for liver fibrosis therapy. In order to further improve the efficacy, we proposed to construct a novel targeted drug delivery system (DDS) based on retinol binding protein receptor (RBPR) which is highly expressed on the surface of HSCs and mediates vitamin A specific uptake by HSCs. According to related literature, silibinin and cyclopamine are expected to inhibit HSCs activation by synergistic effect. In this study, they will be loaded into liposome firstly, which will be then decorated with vitamin A on its surface. This DDS could deliver drugs to HSCs targetedly, contributing to potent therapy for liver fibrosis. Preliminary experiments showed that vitamin A modified targeted liposome could increase drug intake by HSCs significantly, laiding a solid foundation for further study of this project, such as the anti-fibrotic effect and its mechanism in vitro and in vivo. In conclusion, this project is of great significance for effective hepatic fibrosis therapy.

肝纤维化是多种慢性肝损伤的共同病理改变，可发展成肝硬化，甚至肝癌。肝星状细胞（HSCs）的活化是肝纤维化发生发展的中心环节，抑制此过程可有效抑制肝纤维化。因HSCs活化受多方面影响，且不同通路间有相互作用，所以单独抑制某个通路并不能充分抑制此过程。因此，通过共给药从多方面同时抑制HSCs的激活是治疗肝纤维化的有效手段。为了进一步提高药效，基于HSCs表面高表达介导维生素A特异性摄取的视黄醇结合蛋白受体（RBPR），我们构建了一种新型靶向递药系统（Vit A-Lipo）。首先制备Vit A-Lipo，包载具有不同作用机制的抗肝纤维化药物水飞蓟宾和环巴胺，并靶向传递至HSCs，以期实现肝纤维化的有效治疗。预实验表明，Vit A-Lipo确能增加HSCs对药物的摄取，这为本课题后期对载药Vit A-Lipo的抗纤维化作用和机制研究等工作奠定了基础。本项目的开展对肝纤维化的有效治疗具有重要意义。

肝纤维化是多种原因引起慢性肝损伤时共同的病理改变，可导致肝脏结构和功能的异常。肝纤维化以肝星状细胞(HSC)激活为主要特征，HSC的激活会导致细胞外基质(ECM)的过度产生，从而形成肝纤维化。因此，抑制星状细胞活化可能是一种有效的治疗方法。由于HSC的激活受多种途径的控制，因此联合使用不同机制的药物可能比单一治疗更有效。大量文献表明，Hh通路与肝纤维化过程中HSCs的活化、增殖与凋亡以及与其他通路的交互作用等密切相关。而环巴胺正是一种有效的Hh通路抑制剂。此外，姜黄素也能通过激活PPARγ信号通路和调节基质金属蛋白酶活性等途径抑制HSC的活化。因此，在本项目中我们以脂质体为载体包载姜黄素和环巴胺，用于抑制HSC的活化，进而治疗肝纤维化。我们系统分析了载药脂质体的理化特性，以及在基因、蛋白和细胞水平上对HSC增殖、活化和胶原生成的影响。姜黄素和环巴胺包载进脂质体后增加了细胞对药物的吸收。而且，同时载两种药的脂质体对细胞增殖、迁移和侵袭的抑制作用，以及对细胞凋亡的诱导作用和对细胞周期的影响均强于药物溶液或单独载药的脂质体。此外，姜黄素-环巴胺脂质体还能有效抑制HSC的激活和胶原的分泌，显示出抗肝纤维化的协同作用。因此，该递药系统具有治疗肝纤维化的潜力。本项目支持下，项目组参加了多次学术会议，发表了4篇SCI论文，培养博士研究生1名，硕士研究生3名，完成了预期目标。