SIRT1介导褪黑素改善多囊卵巢综合征患者颗粒细胞线粒体损伤的作用及机制研究

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in reproductive women, which lacks effective treatment. Chronic inflammation and oxidative stress induced by mitochondrial injury are the main causes of PCOS pathophysiology. Our preliminary study found that PCOS leaded to mitochondrial injury in granulosa cells; and the expression of SIRT1 was significantly increased and the mitochondrial function was improved after treatment with melatonin. This study will use pathologic, cellular, and molecular biologic technologies, using in vivo and in vitro models, in order to explore the mechanism of melatonin ameliorates mitochondrial injury mediated by SIRT1 in granulosa cells of PCOS: 1) In the aspect of reducing mitochondrial injury, melatonin promotes the expression of SIRT1 in granulosa cells, increasing the activity of Akt to inhibit mitochondrial mPTP, which can stabilize the mitochondrial membrane potential; 2) In the aspect of clearing injured mitochondria, melatonin promotes the expression of SIRT1 in granulosa cells, promoting posttranslational modification of PINK1/Parkin; and promoting LC3 deacetylation to shift LC3 from the nucleus toward the cytoplasm; interaction of PINK1/Parkin with LC3 enhanced mitophagy. This study can provide new insight into therapeutics strategy for PCOS.

多囊卵巢综合征(PCOS)是育龄期女性最常见的内分泌紊乱性疾病，由于其发病机制尚不清楚，临床处理仍较为棘手。研究发现颗粒细胞线粒体损伤引起的慢性炎症、氧化应激是导致PCOS病理生理改变的主要原因。我们前期研究显示：PCOS颗粒细胞存在线粒体损伤；采用褪黑素处理颗粒细胞后其SIRT1表达量显著增加，同时线粒体功能改善。本项目将采用病理、细胞及分子生物学技术，从整体到细胞水平，探讨SIRT1介导褪黑素改善PCOS颗粒细胞线粒体损伤的分子机制：1）在减少线粒体损伤方面，SIRT1通过激活Akt抑制线粒体mPTP，从而稳定颗粒细胞线粒体膜电位；2）在促进清除损伤的线粒体方面，SIRT1又通过翻译后修饰PINK1/Parkin；同时促进LC3去乙酰化使其由细胞核向细胞质转移；PINK1/Parkin与LC3共同作用促进线粒体自噬，从而清除损伤的线粒体。本研究将为临床治疗PCOS提供新思路及新靶点。

多囊卵巢综合征(PCOS)是育龄期女性最常见的内分泌紊乱性疾病，由于其发病机制尚不清楚，临床处理仍较为棘手。研究发现颗粒细胞线粒体损伤引起的慢性炎症、氧化应激是导致PCOS病理生理改变的主要原因。我们前期研究显示：PCOS颗粒细胞存在线粒体损伤；采用褪黑素处理颗粒细胞后其SIRT1表达量显著增加，同时线粒体功能改善。本项目收集临床PCOS患者生物样本，并构建PCOS小鼠模型及SIRT条件性敲除转基因小鼠，从体内及体外两方面，探究SIRT1介导褪黑素改善PCOS颗粒细胞线粒体损伤的分子机制：1）褪黑素通过增强SIRT1表达水平，降低PINK1/Parkin介导的过度的线粒体自噬，从而稳定颗粒细胞线粒体膜电位；2）褪黑素通过增强SIRT1表达水平，改善线粒体膜通道转换孔mPTP开放水平，从而稳定线粒体膜电位，进而改善线粒体膜损伤; 3）SIRT1卵巢颗粒细胞条件性敲除小鼠卵巢组织学结构及卵泡计数同野生型小鼠无显著性差异，需要改进实验进一步研究。本研究提示褪黑素通过SIRT1调控卵巢颗粒细胞线粒体自噬水平及线粒体膜通道转换孔开放水平，改善线粒体膜电位，将为临床治疗PCOS提供新思路及新靶点。