基于SREBPs的补骨脂降脂活性成分发现及机制研究

The sterol regulatory element binding proteins (SREBPs) are a key transcription factors that directly activate a number of genes involved in fatty acid, triglyceride, cholesterol synthesis and uptake, thereby playing an important role in maintaining lipid homeostasis in hepatocytes. The discovery of small molecule compounds that inhibit the transcription factor SREBPs activity has become a hot spot for the treatment of diseases such as obesity, type 2 diabetes, fatty liver and atherosclerosis. The project plans to integrate the methods and techniques of analytical chemistry, molecular biology and chemical biology, and to establish a screening method based on SREBPs activity and nematode lipid metabolism model. This project plans to analyze and identify lipid-lowering active components from Psoralea corylifolia L., to reveal the mechanism of active substances regulating SREBPs. The direct targets of active substances will be identified by photo-affinity labeling technique and protein spectrum analysis. More in-depth study will be carried on the role of active molecules in vitro and in vivo using molecular biology techniques. Based on the above studies, the aim of the study is to find out the active components of lipid-lowering agents by means of high efficient screening method based on the overall chemical composition analysis. Furthermore, using chemical biology techniques, the target protein of active compounds will be identified and new SREBPs regulatory proteins will be discovered.

固醇调节元件结合蛋白（SREBPs）是一类关键的转录因子，可直接激活多个参与脂肪酸、甘油三酯、胆固醇合成与摄取的基因表达，从而在维持肝细胞内的脂质平衡稳态中发挥重要作用。发现抑制转录因子SREBPs活性的小分子化合物，成为发现治疗肥胖、2型糖尿病、脂肪肝和动脉粥样硬化等疾病药物的热点。本项目通过集成分析化学、分子生物学、化学生物学等多学科的方法和技术，建立基于SREBPs活性和线虫脂质代谢模型的天然药物活性成分的筛选方法，分析和鉴别补骨脂中降脂活性成分，揭示活性物质调控SREBPs的作用机制；通过光亲和标记技术，结合蛋白质谱分析，鉴定活性物质的直接作用靶点；利用分子生物学手段对活性分子在体内外与靶点的作用进行深入研究。通过以上研究，旨在整体化学成分解析基础上，通过高效活性筛选方法，快速发现降脂活性成分；通过化学生物学技术手段，鉴定活性化合物作用靶点蛋白，发现新的SREBPs调节蛋白。

建立完善的脂肪肝细胞筛选体系，利用该体系发现了系列具有降脂活性的天然产物化合物，并在动物模型中验证了其活性；发现HSP90β可促进脂质从头合成，参与代谢性疾病进程。随后，对HSP90β调控脂质合成的作用机理进行深入研究。并以HSP90β为靶点从补骨脂中筛选降脂活性化合物corylin，且在体内验证HSP90β特异性抑制剂corylin对肥胖、胰岛素抵抗（Insulin resistance, IR）及动脉粥样硬化（Atherosclerosis，AS）等代谢综合征相关疾病的改善作用；通过小分子微阵列芯片（Small molecule microarray，SMM）方法，发现HSP90β亚型特异性的结合小分子，并对其降脂活性进行研究，发现其中7-aminocephalosporanic acid体内外降脂效果最佳；构建高通量的细胞热转变分析(CETSA)技术，从化合物库中发现与SCAP结合的天然产物石蒜碱；建立基于非标记方法发现中药活性成分靶标的技术，发现异甘草素的结合靶点是IQGAP2，通过IQGAP2-Sirt1轴体内外降低肝脏脂质堆积。期间，发表SCI论文8篇，其中一篇影响因子>10，培养硕士生4名，博士生3名。