子宫内膜异位症患者卵巢颗粒细胞EZH2通过组蛋白甲基化修饰导致女性不孕的作用机制研究

组蛋白甲基化修饰是目前的研究热点，但在内异症的报道甚少。我们发现组蛋白甲基化转移酶EZH2在内异症患者颗粒细胞的表达显著低于正常女性,干扰颗粒细胞EZH2可促进孕酮合成、诱导细胞衰老和凋亡。EZH2与靶基因DNA结合，甲基化修饰临近组蛋白从而抑制基因转录。我们CHIP-Seq及CHIP-PCR证实EZH2可与雌孕激素合成关键催化酶CYP11A1、衰老蛋白P16与P21基因组DNA结合，且干扰EZH2可上调CYP11A1、P16和P21。我们提出内异症患者颗粒细胞EZH2下调，导致CYP11A1、P16和P21基因组蛋白甲基化修饰减弱，影响激素合成和细胞衰老凋亡，导致患者生育力下降。我们拟过表达/干扰EZH2，检测孕酮水平、细胞衰老凋亡变化；构建内异症小鼠和颗粒细胞条件性敲除EZH2小鼠，研究EZH2对小鼠生育力的影响。本项目将明确EZH2在内异相关性不孕的作用机制，为疾病诊治提供潜在靶点。

Histone methylation is a hot topic at present, but few work was reported on endometriosis. We recently found that the expression of histone methyltransferase EZH2 in granulosa cells of endometriotic patients was significantly lower than that in normal women, and interfering with EZH2 in granulosa cells could increase progesterone synthesis, induce cell senescence and apoptosis. EZH2 combines with the genomic DNA of target genes, and modifies adjacent histone methylation, resulting in inhibition of gene transcription. Our previous results of CHIP-Seq and CHIP-PCR confirmed that EZH2 could bind to genomic DNA of CYP11A1, a key catalytic enzyme of sex homone, and P16 and P21, biomarkers of cell senescence. EZH2 Interference could increase CYP11A1, P16 and P21. These data indicated that CYP11A1, P16 and P21 are target genes of EZH2. In this research, we propose that the downregulated EZH2 of granulosa cells in patients with endometriosis leads to the decrease of methylation of genomic DNA of CYP11A1, P16 and P21, and affects sex hormone synthesis and cell senescence and apoptosis, which cause infertility of endometriotic patients. We would like to overexpress or interfere EZH2 in human primary cultured granulosa cells, detect progesterone level, cell senescence and apoptosis. We plan to construct endometriotic mice model and transgenic mice with EZH2 conditional knockout in granulosa cell, and study the effect of EZH2 on fertility of mouse. This project will identify the mechanism of EZH2 function in infertility of patients with endometriosis, and provide potential targets for diagnosis and treatment of the disease.