Astrocyte insulin resistance-induced neuroendocrine defects in pubertal delay and hypogonadotropic hypogonadism

星形胶质细胞胰岛素抵抗诱导青春期延迟和低促性腺激素性性腺功能减退症的神经内分泌缺陷

• 批准号: 10612727
• 负责人: Jennifer Wootton Hill
• 金额: $ 55.17万
• 依托单位: UNIVERSITY OF TOLEDO HEALTH SCI CAMPUS
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-01 至 2027-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10612727
• 关键词: Ablation; Adult; Age; Anabolism; Antral; Astrocytes; Biological; Blood - brain barrier anatomy; Body fat; Brain; Breeding; Calories; Cell Line; Cells; Communication; Complement; Coupling; Data; Defect; Delayed Puberty; Diabetes Mellitus; Dinoprostone; Drops; Eating; Enzymes; Female; Fertility; Food deprivation (experimental); Genes; Genetic; Genetic Transcription; Glial Fibrillary Acidic Protein; Goals; Gonadotropin Hormone Releasing Hormone; Homeostasis; Hormones; Idiopathic Hypogonadotropic Hypogonadism; Impairment; Improve Access; Individual; Infertility; Insulin; Insulin Receptor; Insulin Resistance; Insulin Signaling Pathway; Insulin-Like Growth Factor I; Intermediate Filament Proteins; KISS1 gene; Klinefelter' s Syndrome; Leptin; Measurement; Measures; Menarche; Metabolic; Metabolic Diseases; Metabolic hormone; Molecular; Mus; Neuroglia; Neurons; Neurosecretory Systems; Nutrient; Obesity; Pathway interactions; Patients; Phosphorylation; Play; Population; Preoptic Areas; Presynaptic Terminals; Production; Prostaglandin-Endoperoxide Synthase; Puberty; Radial; Reproduction; Research; Role; Signal Pathway; Signal Transduction; Sperm Count Procedure; Strenuous Exercise; Structure of nucleus infundibularis hypothalami; Synapses; System; Testing; Therapeutic; Time; Viral; Western Blotting; Woman; Work; cyclooxygenase 2; diabetic; girls; glucose uptake; in vivo; insulin signaling; male; men; nerve stem cell; nestin protein; neurochemistry; novel therapeutics; obesity in children; peripubertal period; postsynaptic; presynaptic; promoter; pubertal timing; regenerative; reproductive; reproductive axis; reproductive function; reproductive hormone; response; sensor; sex; spatiotemporal; success; transcription factor

Astrocytes are known to provide support to gonadotropin releasing hormone (GnRH) neurons that control the reproductive axis, for example by releasing prostaglandin E2 (PGE2) required for fertility. Astrocytes may also play a critical role in the brain as metabolic sensors. In response to insulin, astrocytes increase glucose uptake across the blood brain barrier and release metabolites and gliotransmitters to support neuronal function. We have recently demonstrated a unique biological role for astrocytes in coupling fertility to energy availability. We found that the absence of insulin signaling in astrocytes delays puberty, causes hypogonadotropic hypogonadism, and dramatically reduces fertility. This finding is particularly exciting since numerous studies have shown neuronal insulin sensing is unnecessary for reproduction. We have also found that loss of astrocyte insulin sensing reduces PGE2 synthase levels, leading us to hypothesize that astrocyte insulin sensing facilitates GnRH release by promoting astrocyte PGE2 release. New preliminary data suggest that insulin signaling via FOXO pathways alter the transcription of enzymes in the PGE2 biosynthesis pathway, such as COX-2. We will test our hypothesis by pursuing three specific aims. Aim 1) Define the relevant temporal & spatial parameters of astrocyte insulin signaling. Using the tet-on genetic targeting system, we will test whether astrocytes must sense insulin during adulthood or prior to puberty in order to permit normal reproductive function. Astrocyte-specific viral cre administration will also determine the importance of astrocyte insulin sensing in the arcuate nucleus and the rostral preoptic area. Aim 2) Determine the impact of insulin signaling on astrocyte PGE2 gliotransmitter production proximal to reproductive circuits. Measurement of regional PGE2 production will be complemented by AAV targeted disruption of Cox-2 production by astrocytes to determine its importance for fertility. Finally, we will determine whether Kiss1 neurons sense PGE2, leading to altered GnRH release. Aim 3) Determine the molecular role of the insulin/ FOXO pathway in astrocyte PGE2 synthesis. An astrocyte cell line will be used to systematically investigate the major aspects of insulin/FOXO/COX signaling, including phosphorylation, localization, promoter occupancy, and quantitative transcriptional activity measurements. Finally, we will ablate insulin signaling pathways in astrocytes to determine their effect on fertility and PGE2 production. Collectively, these studies will identify how insulin signaling in astrocytes sustains reproductive circuit function. This work will elucidate what may be the dominant mechanism in the mammalian brain whereby insulin permits normal fertility and pubertal maturation. Our results will advance our long-term goal of finding treatment targets for impaired fertility in patients recovering from energy deficits, obese and diabetic populations, and others with idiopathic hypogonadotropic hypogonadism.

已知星形胶质细胞为促性腺激素释放激素 (GnRH) 神经元提供支持，从而控制 生殖轴，例如通过释放生育所需的前列腺素 E2 (PGE2)。星形胶质细胞可能 作为代谢传感器，在大脑中也发挥着关键作用。星形胶质细胞对胰岛素的反应会增加葡萄糖 穿过血脑屏障的摄取并释放代谢物和神经胶质递质以支持神经元 功能。我们最近证明了星形胶质细胞在将生育力与能量结合起来方面具有独特的生物学作用 可用性。我们发现星形胶质细胞中胰岛素信号的缺失会延迟青春期，导致 促性腺激素低下性腺功能减退，并显着降低生育能力。这一发现特别令人兴奋，因为 大量研究表明，神经元胰岛素感应对于生殖来说是不必要的。我们还发现 星形胶质细胞胰岛素感应功能的丧失会降低 PGE2 合酶水平，使我们推测星形胶质细胞 胰岛素感应通过促进星形胶质细胞 PGE2 释放来促进 GnRH 释放。新的初步数据表明 通过 FOXO 途径的胰岛素信号传导改变 PGE2 生物合成途径中酶的转录， 如COX-2。我们将通过追求三个具体目标来检验我们的假设。目标 1) 定义相关 星形胶质细胞胰岛素信号传导的时间和空间参数。使用 tet-on 基因靶向系统，我们将 测试星形胶质细胞是否必须在成年期间或青春期之前感知胰岛素才能正常 生殖功能。星形胶质细胞特异性病毒 cre 的施用也将决定 星形胶质细胞在弓状核和吻侧视前区感知胰岛素。目标 2) 确定影响 胰岛素信号对生殖回路附近星形胶质细胞 PGE2 胶质递质产生的影响。 AAV 对 Cox-2 的定向破坏将补充区域 PGE2 产量的测量 星形胶质细胞的产生以确定其对生育的重要性。最后，我们会判断Kiss1是否 神经元感知 PGE2，导致 GnRH 释放改变。目标 3) 确定胰岛素/的分子作用 星形胶质细胞 PGE2 合成中的 FOXO 途径。星形胶质细胞系将用于系统地研究 胰岛素/FOXO/COX信号传导的主要方面，包括磷酸化、定位、启动子占据、 和定量转录活性测量。最后，我们将消除胰岛素信号通路 星形胶质细胞以确定其对生育力和 PGE2 产生的影响。总的来说，这些研究将确定 星形胶质细胞中的胰岛素信号如何维持生殖回路功能。这项工作将阐明什么可能 哺乳动物大脑中的主要机制，胰岛素通过该机制实现正常的生育能力和青春期 成熟。我们的结果将推进我们的长期目标，即寻找生育力受损的治疗目标 从能量不足中恢复的患者、肥胖和糖尿病人群以及其他特发性患者 低促性腺激素性性腺功能减退症。