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控制的促性腺激素释放激素（GNRH）神经元提供支持 生殖轴，例如，释放生育能力所需的前列腺素E2（PGE2）。星形胶质细胞可能 作为代谢传感器，在大脑中也起着关键作用。响应胰岛素，星形胶质细胞增加葡萄糖 在血脑屏障和释放代谢物和胶质递质的摄取以支持神经元 功能。最近，我们证明了星形胶质细胞在将生育与能量耦合方面具有独特的生物学作用 可用性。我们发现，星形胶质细胞中没有胰岛素信号传导延迟了青春期，原因 性腺功能低下，大大降低了生育能力。这个发现特别令人兴奋，因为 许多研究表明，神经元胰岛素传感是不需要的。我们也发现 星形胶质细胞胰岛素的丧失感应降低了PGE2合酶水平，导致我们假设星形胶质细胞 胰岛素传感通过促进星形胶质细胞PGE2释放来促进GNRH释放。新的初步数据建议 通过FOXO途径的胰岛素信号传导改变了PGE2生物合成途径中酶的转录， 例如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遗传靶向系统，我们将 测试星形胶质细胞是在成年期还是青春期之前必须感觉胰岛素，以便正常 生殖功能。星形胶质细胞特异性病毒CRE给药也将确定 星形胶质细胞胰岛素在弓形核和尾to骨前区域中传感。目标2）确定 星形胶质细胞PGE2 Gliotransmitter生产的胰岛素信号传导近端是生殖电路。 区域PGE2生产的测量将由AAV靶向破坏COX-2互补 由星形胶质细胞生产以确定其对生育的重要性。最后，我们将确定Kiss1是否 神经元感觉PGE2，导致GNRH释放发生了变化。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，启动子占用， 和定量转录活性测量。最后，我们将在 星形胶质细胞确定其对生育能力和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传导如何维持生殖电路功能。这项工作将阐明可能是什么 胰岛素允许正常生育和青春期的哺乳动物大脑中的主要机制 成熟。我们的结果将促进我们寻找治疗目标的长期目标，以使生育能力受损 从能量缺陷，肥胖和糖尿病种群中恢复过的患者以及其他患有特发性的患者 性腺功能低下。