Physiology of hypothalamic neurosteroidal progesterone

 描述（由申请人提供）：神经类固醇，在大脑中从头合成的类固醇，涉及从压力到抑郁、焦虑和认知的功能。一种神经类固醇是黄体酮，一种典型的参与生殖调节的性激素。我们以前已经表明，外周雌二醇（E2）增加下丘脑神经孕酮（neuroP）的合成，启动黄体生成素（LH）激增。LH激增触发排卵和破裂卵泡的黄体化--这是生殖过程中的关键事件。这种雌激素正反馈是由下丘脑吻侧室周核（RP 3V）的kisspeptin神经元调节的。我们建议使用永生化的，女性，成年小鼠下丘脑kisspeptin神经元，mHypoA-51 s，检查LH激增的E2和neuroP信号。初步数据表明mHypoA-51细胞系是RP 3V kisspeptin神经元的良好模型：两者都具有雌激素受体-α（ERα）、孕激素受体（PR）和kisspeptin。与天然kisspeptin神经元一样，mHypoA-51 s中的E2诱导kisspeptin和PR的表达，其被运输到膜。令人惊讶的是，随后的刺激mHypoA-51与P4或星形胶质细胞条件培养基诱导钙释放和增强kisspeptin的表达。我们的总体假设是，E2诱导PR介导neuroP激活kisspeptin神经元，诱导LH峰。将在体外和体内测试三个子假设，以表征雌激素正反馈下雌激素和孕激素信号传导的整合：（1）核ERα诱导PR，PR被运输到膜并被neuroP激活;（2）膜定位PR的neuroP激活刺激kisspeptin释放;（3）kisspeptin神经元中的neuroP信号传导调节LH峰。共同提出的研究将测试一种新的机制，孕酮信号在中枢神经系统，通过外周和中央类固醇信息的整合调节生殖。

 DESCRIPTION (provided by applicant): Neurosteroids, steroids synthesized de novo in the brain, have been implicated in functions ranging from stress to depression, anxiety, and cognition. One neurosteroid is progesterone, a classic sex hormone involved in the regulation of reproduction. We have previously shown that peripheral estradiol (E2) increases hypothalamic neuroprogesterone (neuroP) synthesis, which initiates the luteinizing hormone (LH) surge. The LH surge triggers ovulation and the luteinization of the ruptured ovarian follicle - critical event in reproduction. This estrogen positive feedback is regulated by kisspeptin neurons of the hypothalamic rostral periventricular nucleus (RP3V). We propose to use immortalized, female, adult mouse hypothalamic kisspeptin neurons, mHypoA-51s, to examine the E2 and neuroP signaling underlying the LH surge. Preliminary data indicate that mHypoA-51 cell line is a good model for RP3V kisspeptin neurons: both have estrogen receptor-α (ERα), progesterone receptor (PR) and kisspeptin. Like native kisspeptin neurons, E2 in mHypoA- 51s induces expression of kisspeptin and PR, which is trafficked to the membrane. Surprisingly, subsequent stimulation of mHypoA-51s with P4 or astrocyte conditioned media induces calcium release and augments kisspeptin expression. Our overall hypothesis is that E2 induced PR mediates neuroP activation of kisspeptin neurons to induce the LH surge. Three sub-hypotheses will be tested in vitro and in vivo to characterize the integration of estrogenic and progestational signaling underlying estrogen positive feedback: (1) nuclear ERα induces PR, which is trafficked to the membrane and activated by neuroP; (2) neuroP activation of membrane localized PR stimulates kisspeptin release; and (3), neuroP signaling in kisspeptin neurons regulates the LH surge. Together the proposed studies will test a novel mechanism of progesterone signaling in the CNS, through which integration of peripheral and central steroidal information regulates reproduction.