海马GPER介导雌激素调控类胎盘发育的分子机制研究

Seahorses are representative male pregnant animals. Embryos develop in a specialized brood pouch of male seahorse. Placenta-like tissue in the brood pouch provides protection, gas exchange, immunoprotection and limited nutrient to embryos during pregnancy period. We have found that serum estrogen level increased a lot in pregnant male seahorses. Seahorse GPER gene is under strong positive selection and one paralleled replacement at position 142 is identified in placental mammals and seahorse. Much higher GPER expression was found in the brood pouch compared to other seahorse tissues. These results suggest that GPER-dependent effects of estrogen might play an important role in regulating placenta-like tissue development. This project intends to detect the spatiotemporal expression pattern and the location of GPER gene in brood pouch, to analyze the correlation between GPER expression and placenta-like tissue. Through estrogen treatment experiment, the effects on placenta-like tissue structure and GPER expression will be detected to clarify the role of GPER in placenta-like tissue development. Besides, GPER signaling pathway in the placenta-like tissue will be analyzed based on transcriptome analyses and Gene Co-expression Network Analysis, so as to clarify the molecular mechanism of regulation of GPER mediated estrogen on placenta-like tissue development. Information obtained in this study will be beneficial for understanding the endocrine regulatory mechanism of male pregnancy, and will also provide scientific basises for seahorse conservation.

海马是雄性卵胎生鱼类，雄海马育儿袋发育形成类胎盘，为胚胎提供溶氧、少量营养和免疫保护。然而，类胎盘发育的分子调控机制目前尚无相关研究。申报人前期研究发现，雄海马怀孕时期雌激素水平显著升高；雌激素膜受体GPER在育儿袋内特异性高表达；GPER功能域与哺乳动物趋同进化。相关结果初步证明GPER介导雌激素调控海马类胎盘发育。本项目拟分析海马GPER在不同怀孕时期的时空表达模式，结合类胎盘结构，阐述GPER与类胎盘发育的相关性；通过雌激素浸浴实验，研究类胎盘结构变化和GPER表达特征，揭示雌激素对类胎盘发育的影响，阐明GPER在雌激素调控类胎盘发育中的作用；基于转录组分析和基因共表达分析方法，研究海马GPER调控信号通路与类胎盘发育的相关性，阐明GPER介导雌激素调控类胎盘发育的分子机制。本课题不仅对于阐明雄性卵胎生行为的调控机制具有重要意义，同时为开展海马资源保护提供科学依据。

海马是雄性卵胎生鱼类，雄海马育儿袋发育形成类胎盘，为胚胎提供溶氧、少量营养和免疫保护。认识育儿袋及类胎盘发育的分子调控机制，是认识海马雄性育儿进化机制和开展海马资源保护的重要抓手。申报人围绕海马育儿袋的发育和怀孕功能，以GPER介导雌激素对育儿袋的调控效应为切入点，综合比较基因组学、转录组学、外源激素处理实验等方法，开展了一系列研究，主要结果包括：.海马雌激素膜受体GPER在育儿袋内特异性高表达，且怀孕时期显著高于怀孕时期，但在其他海龙科物种的非封闭式育儿袋内表达量普遍很低，暗示雌激素通过GPER在海马育儿袋内发挥调节作用；海马GPER在基因组中的共线性分布保守，但编码氨基酸受到显著正选择，与哺乳动物趋同进化，暗示海马GPER介导的雌激素效应在海马种可能发生特化；基于外源激素浸浴实验，发现环境性激素会促进海马卵巢发育，但会抑制雄鱼育儿袋生长，并可能导致精巢雌化，转录组分析表明，外源雌激素和孕激素显著改变精巢精子发生相关基因和育儿袋细胞间质发育相关通路基因的表达模式。本课题不仅对于阐明鱼类雄性胎生行为的调控机制具有重要意义，同时为开展海马资源保护提供科学依据。.依托本项目，在Science of the Total Environment等期刊发表学术论文5篇，协助培养硕士研究生一名，项目负责人于2018年获得副高级职称，2020年获得国家基金面上项目资助。