中药地黄活性成分梓醇基于PGC-1α信号通路调节骨骼肌线粒体可塑性的抗糖尿病机制研究

Mitochondrial plasticity is defined as changes of mitochondrial activity, mitochondrial content or oxidative phosphorylation capacity due to altered metabolic conditions. Impaired mitochondrial plasticity, that is, response to metabolic regulation, seems to be characteristic of many diabetic patient groups. PPAR-γ coactivator-1α (PGC-1α) , a coactivator of most nuclear receptors and several other transcription factors, is highly expressed in tissues with intense oxidative metabolism and rich mitochondria content . Accumulating evidence indicates that PGC-1α is a crucial regulator of mitochondrial biogenesis and oxidative metabolism in most cell types, including skeletal muscle and brown fat. So it is an valuable target for the pathogenesis and drug intervention of diabetes. Catalpol, an iridoid glucoside , showed a significant hypoglycemic effect on type I and II diabetic animals. Strikingly, Catalpol treatment improved mitochondrial function (membrane potential, ATP content, morphological changes) and enhanced PGC-1α expression in skeletal muscle. This project is designed to study whether PGC-1α contributes to the protective effects of the Catalpol on diabetes by improve mitochondrial function. Using different diabetic animals and in vitro cell culture models and various molecular, cellular techniques such as gene silencing/overexpressing, real-time PCR, Western blot, flow cytometry, luciferase reporter gene, we will investigate the mechanism of anti-diabetic activity of catalpol and further clarify the role of the mitochondrial plasticity and PGC-1α pathway in diabetes. It opens up new avenues for the development of preventive/therapeutic to treat diabetes .

线粒体可塑性定义为不同代谢条件下线粒体活性、数量及氧化磷酸化能力的变化。骨骼肌线粒体可塑性损害是许多糖尿病患者的共同特征。PGC-1α是近年来倍受关注的多功能共激活因子，是线粒体可塑性和能量代谢调节的核心信号分子。我们前期实验发现地黄活性成分梓醇对糖尿病动物有良好的非胰岛素依赖性降糖作用，可显著改善糖尿病模型动物骨骼肌PGC-1α表达下降和线粒体异常（膜电位下降，ATP减少，形态改变）。本课题将采用基因沉默/基因过载、荧光定量PCR、Western、流式细胞术、荧光素酶报告基因等多种分子、细胞试验技术，选择不同糖尿病模型及体外培养的骨骼肌细胞模型，从糖尿病模型发生、发展多个时间点，探讨梓醇基于PGC-1α信号通路调节骨骼肌线粒体可塑性的抗糖尿病机制，阐明骨骼肌线粒体及PGC-1α通路在糖尿病发生及防治中的意义，为糖尿病等代谢性疾病防治提供新的思路和治疗药物。

本项目围绕 “梓醇基于PGC1α 信号通路调节骨骼肌线粒体可塑性的抗糖尿病机制”研究设想，参照项目申请书的相关内容，采用多种分子、细胞试验技术，选择不同糖尿病模型（STZ诱导大鼠I型糖尿病模型，高脂饲料诱导C57小鼠II型糖尿病模型，KKay小鼠，db/db小鼠）及体外培养的骨骼肌C2C12细胞模型，从糖尿病模型发生、发展多个时间点开展研究，阐明梓醇能够通过AMPK/PGC1α 通路调节骨骼肌线粒体可塑性，同时通过MyoD/MyoG信号通路，促进糖尿小鼠骨骼肌和C2C12细胞的肌发生（myogenesis）过程，调节骨骼肌肌纤维类型转换和功能，改善骨骼肌胰岛素敏感性，提高骨骼肌细胞对葡萄糖的摄取与利用而达到降血糖的作用；对于高糖状态下肝脏线粒体功能和质量异常，梓醇亦具有较好的改善作用。. 本项目已发表SCI论文1篇和中文核心论文2篇，另投稿SCI论文2篇，参加国际会议交流1次，申请专利1项，培养硕士研究生2名，并与骨骼肌生理领域国际知名实验室合作开展后续研究。本项目阐明了梓醇不同于现有糖尿病治疗药物的特点和新颖性，除了理论机制创新之外，还很好的支持了梓醇作为糖尿病创新药开发，项目联合单位研发的“梓醇片”取得国家食品药品监督管理局中药1类药物临床试验批件，并获得国家科技重大专项等资助。.