PCSK9在多囊卵巢综合征脂代谢及卵巢功能异常中的作用及其机制研究

Polycystic ovary syndrome (PCOS) is one of the most common diseases among women in reproductive age and its most common characteristics are dyslipidemia and ovarian dysfunction. It has been approved there is a close relationship between lipid metabolism and ovarian function. Proprotein convertase subtilisin/kexin type-9 (PCSK9) was found to be a secreting lipid metabolic regulator in 2003, which increase LDL-C level in plasma as its binding to low density lipoprotein receptor (LDLR) and mediates its degradation in hepatocytes. However, there is no related research about whether PCSK9 involved in the pathological process of PCOS. In our previous studies, we have observed that the expression of PCSK9 increased in plasma and ovary in PCOS patients and model mice. Thus, we speculate that the increase of PCSK9 is also an important reason for dyslipidemia in PCOS patients, and it may directly or indirectly affect the function of ovary through affecting the microenvironment of follicular development, or impeding the cholesterol uptake of follicular cells. In this research, we are to use the methods of clinical epidemiology, associated with the techniques of reproductive physiology, reproductive endocrinology and cellular and molecular biology to explore the correlation between PCSK9 and PCOS, the role of PCSK9 in abnormal lipid metabolism and ovarian dysfunction of PCOS and the mechanism of its effect on ovarian function. This study will be helpful to reveal the pathological mechanism of PCOS from a new perspective, and provide a new strategy for the diagnosis and treatment of PCOS.

脂代谢和卵巢功能异常是多囊卵巢综合征 (PCOS)最普遍的特征。脂代谢与卵巢功能之间存在着密切联系。PCSK9是2003年首先在肝脏发现的一个分泌型脂质代谢调控因子，该蛋白负调控肝细胞膜LDLR的表达，使血浆LDL-C升高。然而，PCSK9这样一个重要的脂代谢负调控因子是否也参与PCOS的病理过程尚无相关研究。我们前期预实验结果提示PCOS患者血中及PCOS模型动物血中和卵巢组织存在PCSK9表达异常增加，据此推断，PCSK9异常增加可导致PCOS患者全身脂代谢异常，间接影响卵巢卵泡发育的微环境，也可能直接影响卵巢的胆固醇摄取利用进而影响卵巢功能。本项目采用临床流行病学研究，结合动物实验及细胞生物学实验探讨PCSK9与PCOS相关性；PCSK9在PCOS脂代谢及卵巢功能异常中作用；PCSK9影响卵巢功能的机制，从一个新的视角进一步揭示PCOS的病理机制，为PCOS的诊断治疗提供新的策略。

我们推测PCSK9异常增加可导致PCOS患者全身脂代谢异常，间接影响卵巢卵泡发育的微环境，也可能直接影响卵巢的胆固醇摄取利用进而影响卵巢功能。本项目采用临床流行病学研究方法，结合采用生殖生理，生殖内分泌和细胞分子生物学技术手段进行动物实验及细胞学实验探讨首先研究PCSK9异常表达与PCOS脂代谢及卵巢功能异常之间的相关性；其次，研究PCSK9在PCOS脂代谢及卵巢功能异常中的作用；再次，探索PCSK9影响卵巢功能的分子机制；最后，我们进一步揭示了PCOS小鼠PCSK9表达上调的主要原因和分子机制。主要研究结果如下：（1）PCSK9在PCOS患者血清中显著增高，PCSK9水平与TC、LDL-C、ApoB、T和LH/FSH呈显著正相关，说明PCSK9与脂代谢、卵巢功能异常有关；（2）PCOS模型小鼠血清、肝脏和卵巢组织PCSK9的表达明显增加，同时伴有脂代谢异常和卵巢功能障碍，PCSK9基因敲除及PCSK9抑制剂均可以改善PCOS小鼠脂代谢、卵巢形态、内分泌以及排卵功能，证明PCSK9在PCOS脂代谢紊乱和卵巢功能异常中发挥作用；（3）卵巢局部过表达PCSK9能够直接导致卵巢形态、内分泌和排卵功能的改变，出现部分类似PCOS的表现，证明PCSK9对卵巢功能有直接影响；（4）PCSK9对卵巢功能作用的机制有三个方面：减少LDLR表达从而影响胆固醇摄取和激素合成；增加雌、雄激素合成关键酶CYP17A1和aromatase的表达；激活Bcl-2/Bax-caspase-3信号通路，直接抑制卵泡细胞增殖诱导凋亡；（5）高脂饮食通过上调肝脏和卵巢组织中的SREBP2表达，诱导PCSK9表达增强。本项目立足PCSK9，结合PCOS的疾病特征，从全新视角探讨导致PCOS脂代谢异常及卵巢功能障碍的病理机制，该研究成果可为该疾病的诊断、治疗和预防提供新的切入点。