应用纳米载体靶向性抑制肝星状细胞糖酵解以治疗肝纤维化

Liver fibrosis,cirrhosis and liver cancer are the major human diseases. Deregulated proliferation and activation of myofibroblastic hepatic stellate cells (MF-HSCs) is an important source for fibrosis pathogenesis. Since advanced glycolysis is essential for their proliferation and MF phenotype, we selectively attack cellular glycolysis of the active HSCs to suppress their proliferation and reverse their myofibroblastic phenotype to the quiescent one. 10-hydroxy-camptothecin(CPT) is chosen to inhibit the roles of hypoxia inducible factor (HIF1A), the critical modulator of glycolysis; RNA interference (RNAi) is employed to downregulate expression of the rate limiting enzyme gene Hexokinase 2 and type 2 muscle pyruvate kinase. Nanoparticle-based drug carrier system is designed to further improve the targeting of drug at the active HSCs by coupling cell ligand folate to nanoparticles, and to better control drug release via the association of drug-nanoparticles with a pH-sensitive hydrozon linker. The newly developed therapeutic method possesses several advantages: 1) Simultaneously inhibits proliferation, migration and MF phenotype of the active MF-HSCs by lowering glycolysis; 2）Modulates the release of drug into the active MF-HSC by the pH-sensitive linker; 3) Folate-modified nanoparticle provides the targeting of the drug at MF-HSCs with the high expression of folate receptor. Our aim is to develop new therapies for fibrosis with better efficacy, lower side-effects and less costs.

肝纤维化引起的肝硬化和肝癌是人类主要的疾病之一。快速增殖的肌纤维母细胞样的活化肝星状细胞（HSC）是导致肝纤维化的主因。活化HSC需要进行旺盛的糖酵解活动以维持其增殖和肌纤维母细胞样的表型。本项目分别以10-羟基喜树碱和小干扰RNA来抑制糖酵解关键调控因子（缺氧诱导因子1α）的活性和糖酵解限速酶基因的表达，选择性地遏制活化HSC的糖酵解，进而抑制其增殖、迁移并逆转其肌纤维母细胞样的表型，从多方面消除其对肝纤维化的促进作用。本项目同时应用可降解的纳米载体载送药物以改善其疗效和毒性。针对活化HSC中表达水平显著升高的叶酸受体，采用叶酸配体修饰纳米载体以促进活化HSC对药物的摄取，增强药物的靶向性。针对活化HSC独特的旺盛糖酵解活动，在载药系统中引入对pH值敏感的腙键，进一步控制药物在活化HSC中的释放。本研究着力发展具有多重靶向性的新型肝纤维化治疗手段，更好地保证药物疗效并减少其毒性。

肝纤维化、肝硬化和肝癌严重威胁人类健康。肝损伤激活肝星状细胞（HSCs）是导致肝纤维化的主因。选择性抑制活化HSCs旺盛的糖酵解活动可遏制其快速扩增并逆转其肌纤维母细胞样表型，进而治疗肝纤维化。本项目首次发现喜树碱（而非10羟基喜树碱）可特异性地减少活化HSCs中缺氧因子1α蛋白、下调糖酵解限速酶和逆转HSCs激活表型。进而采用维生素A偶联的特异性靶向HSCs胶束载送喜树碱、分别对四氯化碳慢性毒害和胆囊结扎诱导的小鼠肝纤维化进行治疗，成功地通过抑制活化HSCs的糖酵解活动实现了对肝纤维化发生的遏制和对肝损伤的修复。其次，我们发现HSCs在激活再程序化的过程中增强α型叶酸受体的表达，并进一步揭示叶酸为活化HSCs维持激活表型和大量扩增所必需。首次应用叶酸作为主动靶向活化HSCs的新型配体修饰喜树碱载药胶束、对四氯化碳慢性诱导的小鼠肝纤维化进行了有效的药物干预。我们还依据活化HSCs分泌乳酸的行为、制备了酸敏感性的喜树碱药物控释体系；并基于纤维化肝脏组织中细胞外基质蛋白沉积的病理特征，制备了高亲性结合I型胶原蛋白的、主动识别活化HSCs的双靶向性改造干扰素γ，为发展多重靶向性的抗纤维化药物奠定了基础。..项目资助期间发表SCI期刊论文3篇和中文核心期刊论文2篇，1篇国际会议摘要被Digestive Disease Week 2017选为口头报告；另有2篇论文投递SCI期刊现在补充材料、1篇论文投递SCI期刊在审；申请中国发明专利6项。