Cross-talk between Estrogen and Metabolic Hormone Signaling in Kisspeptin Neurons

项目摘要 我们研究计划的长期目标一直是阐明代谢状态的机制(S) 17β-雌二醇(E_2)调节弓状核Kisspeptin(Kiss1ARH)神经元回路，这对 协调女性体内的能量平衡和生殖。众所周知，雌二醇是厌食症，而且 受雌激素直接调节的Kiss1神经元对青春期发育和成年生殖是必不可少的 成功。然而，它们在控制其他体内平衡功能方面的作用才刚刚显现。此前，我们发现， 瘦素和胰岛素通过典型瞬时受体电位(TRPC)5通道兴奋Kiss1ARH神经元 并提出它们可能是控制能量动态平衡的重要枢纽。最近， 我们发现，高频光遗传刺激Kiss1ARH神经元释放谷氨酸来兴奋 厌食性前阿片黑素皮质素(POMC)神经元，但抑制与厌食性神经肽Y/刺鼠相关的 雌性和雄性的多肽(AgRP)神经元。雌二醇增加囊泡型谷氨酸转运体2(Vher2) 雌性Kiss1ARH神经元的mRNA表达和谷氨酸释放增强POMC兴奋和 AgRP抑制。与之相反，去势大鼠的Vlu2基因表达和谷氨酸释放增加。 与完整的雄性相比，说明在谷氨酸的合成和释放方面存在重要的性别差异。钥匙 雌激素上调兴奋性阳离子通道导致兴奋性增加和谷氨酸能突触 变速箱。最近，我们发现选择性膜雌激素受体(GqmER)激动剂STX 增加Kiss1ARH神经元的兴奋性，而不下调多肽的表达。它也减少了 雌性和雄性的食物摄入量。因此，我们假设Kiss1ARH神经元中的雌激素信号 对于增加Kiss1ARH神经元的兴奋性和维持动态平衡功能至关重要 繁衍成功。我们的多学科方法结合了一套强大的细胞、分子、遗传学 和光遗传工具，以及我们在分子生物学、电生理学和整个动物方面的综合专业知识 生理学以解决以下目标：(1)测量雌激素介导的兴奋性增加 用GCaMP6和Voltron记录Kiss1ARH神经元；(2)阐明 Kiss1ARH突触传入下丘脑室旁核神经元 它对雌二醇(STX)处理的雌性和STX处理的雄性摄入量的影响；和(3)阐明雌激素 Kiss1ARH神经元突触传入对下丘脑背内侧核神经元的调制及其作用 雌激素STX处理的雌性和雄性STX处理的能量消耗。阐明电路和信令 E2和STX作用的级联反应将提供神经生理学/神经药理学 更全面地理解Kiss1ARH神经元协调的细胞机制的框架 动态平衡功能与生殖有关。

Project Summary The long range goals of our research program has been to elucidate the mechanism(s) by which metabolic states and 17β-estradiol (E2) regulate arcuate nucleus kisspeptin (Kiss1ARH) neuronal circuits that are critical for coordinating energy homeostasis and reproduction in females. It is well known that E2 is anorexigenic, and that Kiss1 neurons, which are directly regulated by E2, are essential for pubertal development and adult reproductive success. However, their role in the control of other homeostatic functions is just emerging. Earlier, we found that Kiss1ARH neurons are excited by leptin and insulin via canonical transient receptor potential (TRPC) 5 channel signaling and proposed that they may serve as an important hub in the control of energy homeostasis. Recently, we found that high frequency optogenetic stimulation of Kiss1ARH neurons releases glutamate to excite the anorexigenic proopiomelanocortin (POMC) neurons but inhibit the orexigenic neuropeptide Y/agouti-related peptide (AgRP) neurons in both females and males. E2 increases vesicular glutamate transporter 2 (Vglut2) mRNA expression and glutamate release from female Kiss1ARH neurons to augment the POMC excitation and AgRP inhibition. In contrast, Vglut2 mRNA expression and glutamate release are increased in castrates as compared to intact males, illustrating an important sex difference in the synthesis and release of glutamate. Key excitatory cationic channels are upregulated by E2 leading to increased excitability and glutamatergic synaptic transmission. Recently, we have found that the selective membrane estrogen receptor (GqmER) agonist STX increases the excitability of Kiss1ARH neurons without downregulating the peptide expression. It also decreases food-intake in both females and males. Therefore, we hypothesize that estrogenic signaling in Kiss1ARH neurons is important for increasing Kiss1ARH neuronal excitability and maintenance of homeostatic functions critical for reproductive success. Our multidisciplinary approach incorporates a powerful set of cellular, molecular, genetic and optogenetic tools, and our combined expertise in molecular biology, electrophysiology, and whole animal physiology to address the following aims: (1) to measure the estrogenic-mediated increase in excitability of Kiss1ARH neurons using GCaMP6 and Voltron recordings; (2) to elucidate the estrogenic modulation of the synaptic input from Kiss1ARH to hypothalamic paraventricular nucleus neurons using optogenetic stimulation and its effects on food intake in E2 (STX)-treated females and STX-treated males; and (3) to elucidate the estrogenic modulation of synaptic input from Kiss1ARH neurons to hypothalamic dorsomedial nucleus neurons and its effects on energy expenditure in E2 (STX)-treated females and STX-treated males. Elucidating the circuits and signaling cascades underlying the actions of E2 and STX will provide a neurophysiological/neuropharmacological framework for a more thorough understanding of the cellular mechanisms by which Kiss1ARH neurons coordinate homeostatic functions with reproduction.