BPTF在早发性卵巢功能不全发病中的作用及机制研究

Premature ovarian insufficiency (POI), defined as decline of ovarian function before the age of 40, affect the quality of women’s lives. The underlying etiology for POI remains to be revealed. The role for immune factor in the pathogenesis of POI gained increasing attention in recent years. In the previous study, we found that the percentage of Treg cells and the level of IL-10 were significantly lower in the peripheral blood of POI patients than those in the healthy controls. Moreover, we have identified bromodomain PHD finger transcription factor (BPTF) protein, a central component of chromatin-remodeling complexes, is down-regulated in the Treg cells of POI patients. Interestingly, Treg cell-specific BPTF deletion led to defective Treg cell function, increased lymphocyte infiltration in the ovarian tissues. These findings suggest that the deregulation of BPTF expression, resulting in the Treg cell dysfunction, might affect the immune dysfunction in POI and participate the development of POI. Based on the previous results, the present study focuses on the effect of BPTF on Treg cells and ovarian function, aiming to clarify the role and underlying mechanism of BPTF interact with Smad2 regulate Treg cell function in immune dysfunction of POI. The success of the proposed study will not only reveal the importance and the critical mechanisms of BPTF and Treg cell function in POI, but also be helpful for identifying the novel biomarkers and therapeutic targets of POI.

早发性卵巢功能不全（premature ovarian insufficiency, POI）指女性40岁前闭经，对其生育力及健康造成严重影响，病因复杂。近年来POI的免疫因素日益受到关注，具体机制尚不明确。我们前期发现，POI患者调节性T细胞（Treg）比例及白介素-10水平明显下降，且Treg细胞的重要调节因子染色质重塑蛋白BPTF表达显著下调；构建Treg细胞内特异性敲除BPTF小鼠，发现卵巢内有大量淋巴细胞浸润及Treg细胞抑制功能下降，提示BPTF异常表达可能导致Treg细胞缺陷影响卵巢功能。本项目拟在前期基础上，探讨BPTF对Treg细胞关键转录因子及对卵巢功能的影响，阐明BPTF与TGF-β信号通路重要因子Smad2的协同作用及参与调控Treg功能缺陷致POI免疫失衡的机制，为POI的早期诊断及干预提供新的策略。

早发性卵巢功能不全（premature ovarian insufficiency, POI）指女性在40岁前卵巢衰退的临床综合征，该病对女性的健康及生育力造成严重影响。POI病因复杂，包括遗传因素、免疫因素、环境因素、医源性因素等。通过研究POI患者Treg细胞及其关键性转录因子FOXP3表达情况，发现POI的发生可能与循环中Treg细胞的功能异常、FOXP3基因表达水平降低及异常分泌的细胞因子有关。此外，本研究首次通过分析FOXP3基因SNPs，总计发现了43个FOXP3 SNP，其中25个已知的SNP，而18个是新发现的SNP，5个SNP的杂合突变被发现在POI患者与正常对照组之间存在统计学差异，提示FOXP3调控区域的遗传变异在中国人群特发性POI中起重要作用，此为临床上免疫性POI诊治提供新思路。本课题组前期研究发现POI患者中存在HFM1（helicase for meiosis 1）基因突变。通过构建Hfm1基因敲除小鼠，发现Hfm1-cKO雌性小鼠的成熟卵母细胞质量明显下降，卵母细胞出现形态异常、不对称分裂，且是通过高尔基体相关途径参与调节。随后构建Hfm1敲低的腺病毒模型，发现Hfm1敲低后的小鼠卵巢中卵母细胞明显减少、凋亡增加，减数分裂被阻滞在双前期前。敲除鼠模型得到与腺病毒敲低类似的结果，明确了Hfm1影响小鼠卵母细胞第一次减数分裂前期中染色体断裂修复和联会过程，且可影响FUS蛋白泛素化水平，此为阐明HFMI参与POI发病的分子机制提供理论基础。众所周知氯氰菊酯（CYP）为日常生活中常见的内分泌干扰物，通过研究CYP暴露的小鼠模型，发现其动情周期明显紊乱，卵巢内原始卵泡和初级卵泡较对照小鼠明显减少；CYP组小鼠卵巢内细胞凋亡水平明显增加，与CYP暴露水平呈剂量依赖关系，凋亡信号主要定位于颗粒细胞。CYP处理KGN细胞系，发现线粒体凋亡相关蛋白、线粒体膜电位、活性氧水平、凋亡率均明显增加，提出CYP暴露可通过颗粒细胞的线粒体损伤影响卵巢储备功能，为临床上发生环境因素或特发性POI患者提供了干预策略。