Estrogen modulation of hypothalamic arcuate neurons

描述（由申请人提供）：下丘脑弓状核中的神经元群体表达阿黑皮素原（POMC），这是一种多肽前体，当切割时产生α-黑素细胞刺激激素（α-MSH）和β-内啡肽（β-末端）。这些产物参与许多稳态功能的调节，如生殖、体液平衡、食欲、压力和动机。虽然雌激素影响POMC基因表达已被公认，但其分子机制尚未阐明。本研究旨在探讨雌激素作用于弓状POMC神经元导致α-MSH和β-末端释放增加的分子机制。比较下丘脑基因表达变化的初步微阵列结果显示，PI 3激酶p55 γ上调，这是PI 3激酶信号通路的一部分。使用单细胞逆转录PCR和原位杂交，我将确定是否PI 3 Kp 55 γ是本地化的POMC弓状神经元。第二，我将验证微阵列发现，PI 3 Kp 55 γ是由雌激素调节使用RNase保护试验和定量实时PCR。最后，我将使用全细胞记录确定POMC弓状神经元中雌激素信号传导的PI 3 K通路的功能。

DESCRIPTION (provided by applicant): A population of neurons in the arcuate nucleus of the hypothalamus expresses proopiomelanocortin (POMC), a polypeptide precursor that when cleaved yields alpha-melanocyte-stimulating hormone (alpha-MSH) and beta-endorphin (beta-end). These products are involved in the regulation of many homeostatic functions such as reproduction, fluid balance, appetite, stress and motivation. Although, it is well established that estrogen affects POMC gene expression, the molecular mechanisms have not been elucidated. This proposal aims to investigate the molecular mechanisms of estrogen action on the arcuate POMC neurons leading to increased release of alpha-MSH and beta-end. Preliminary microarray results comparing gene expression changes in the hypothalamus showed the upregulation of PI3 kinase p55gamma, which is part of the PI3-kinase signaling pathway. Using single-cell reverse-transcription PCR and in situ hybridization, I will determine if PI3Kp55gamma is localized in POMC arcuate neurons. Second, I will validate the microarray finding that PI3Kp55gamma is regulated by estrogen using RNase protection assays and quantitative real-time PCR. Finally, I will determine the function of the PI3K pathway in estrogen signaling in POMC arcuate neurons using whole-cell recordings.