双酚A暴露经由雌激素受体影响谷氨酸能神经网络发育及功能的分子机制

Bisphenol A (BPA) can be detected in more than 90% of people. Studies have revealed that BPA exposure could cause neurodevelopmental abnormalities in children, and that estrogen receptor (ER) regulated the development and function of glutamatergic neural networks. Besides, it was revealed that BPA exposure affected the development and function of neural networks via ER. However, human embryonic stem cells have not been found to be used as the model to study the developmental toxicity of glutamatergic neural networks. Therefore, the project would start from ER, and perform experiments on BPA exposure and ER interventions during differentiation of human embryonic stem cells into glutamatergic neural networks. Firstly, key ER signaling and pathways related to glutamate homeostasis and its receptor signaling involved in the developmental toxicity of BPA are to be found to elucidate molecular mechanisms by which disorders of ER signaling affect the development and function of glutamatergic neural networks via pathways related to glutamate homeostasis and its receptor. Secondly, key steroid hormone (KH) synthetase interventions are to be performed to investigate how KH disorders are induced by BPA exposure, and confirm whether there is feedback regulation between KH and ER after KH related to disorders of ER signaling and the developmental toxicity of BPA is found. Ultimately, the project is to elucidate molecular mechanisms by which disorders of ER signaling induced by BPA exposure affect the development and function of glutamatergic neural networks via disrupting pathways related to glutamate homeostasis and its receptor signaling. The project would provide new insights into neurotoxicity studies of BPA.

双酚A（BPA）在90%以上的人检出。研究表明，孕期BPA暴露致儿童神经发育异常；雌激素受体（ER）调控谷氨酸能神经发育及功能；BPA暴露经由ER影响神经发育及功能。然而，尚未发现以人胚胎干细胞为模型研究BPA影响谷氨酸能神经网络发育的报道。因而，本项目拟从ER入手，在人胚胎干细胞分化成谷氨酸能神经网络过程进行BPA暴露及ER干预，查找BPA神经发育毒性相关的关键ER信号、谷氨酸稳态及受体信号通路，阐明ER信号紊乱经由谷氨酸稳态及受体通路影响神经网络发育及功能的分子机制；其次，找出与ER信号紊乱及神经发育毒性相关的关键类固醇激素（KH），并经KH合成酶干预，阐明BPA暴露如何诱发KH紊乱，并确认KH与ER是否存在反馈调节机制；最后，阐明BPA暴露如何诱发ER信号紊乱，进而扰乱谷氨酸稳态及受体信号通路，影响谷氨酸能神经网络发育及功能的分子机制。本项目可为BPA神经毒性研究提供新思路和新认识。

双酚A（Bisphenol-A,BPA）是一种常见的环境内分泌干扰物，并且大量存在于各种聚碳酸酯和塑料制品中。大量证据表明BPA暴露与多种神经心理学障碍、神经行为异常和神经退行性疾病相关。本项目针对干细胞培养和分化面临的多种问题，对体外构建神经网络分化方法进行改进，并以此作为细胞模型进行BPA的神经毒性作用进行研究。结果发现BPA显著减少了神经突触的密度，损伤树突棘，并导致神经细胞胞体肿胀。同时，BPA显著抑制了微管结构蛋白（MAP2）mRNA和蛋白的表达，并诱发神经细胞凋亡。BPA作为兴奋性神经毒性物质，可在0-10μM浓度慢性暴露后显著上调神经突触蛋白（SYN和PSD-95）的蛋白表达水平，并增强这两种蛋白共定位。随后进一步研究发现BPA通过增加离子型谷氨酸受体的活性和钙离子通透性引起神经细胞钙离子过度内流。钙超载和氧化/氮应激相互促进，进一步引起神经细胞内细胞器损伤，包括线粒体损伤和内质网应激。通过GO富集分析发现，与对照组相比1μM和10μM BPA调控了122个相同Term。KEGG富集分析结果显示，1μM和10μMBPA均调控了hGNs中的MAPK信号通路、PI3K-AKT、粘着斑、ECM受体相互作用通路、肿瘤坏死因子信号通路、肌动蛋白细胞骨架的调控、近端小管碳酸氢盐再生和蛋白质消化吸收。综上所述，本项目研究结果为进一步研究相关毒理和病理机制及提供预防与干预措施提供科学依据。