Regulatory Role of Nitric Oxide in Adrenal Cortisol Synthesis Following Long-Term

一氧化氮在长期后肾上腺皮质醇合成中的调节作用

基本信息

批准号：
8327782
负责人：
Charles A Ducsay
金额：
$ 19.37万
依托单位：
LOMA LINDA UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/8327782
关键词：
Acclimatization Acute Address Adrenal Cortex Adrenal Glands Adult Altitude Automobile Driving CYP11A1 gene Cattle Cells Cholesterol Chronic Chronic stress Clinical Corticotropin Cysteine Cytochrome P450 DNA Binding Development Disease Endocrine Enzymes Fetal Development Fetal Growth Fetal Growth Retardation Fetus Free Radicals Gene Targeting Heat-Shock Proteins 90 Hydrocortisone Hypoxia Laboratories Life Long-Term Effects MAPK3 gene MEKs Mediating Messenger RNA Mixed Function Oxygenases Newborn Infant Nitric Oxide Nitric Oxide Synthase Output Phosphorylation Phosphorylation Site Physiological Pituitary Gland Plasma Pregnancy Production Protein Isoforms Proteins Regulation Research Design Response Elements Role Secondary to Sheep Side Signal Pathway Signal Transduction Site Steroid biosynthesis Steroids Stress Testing Tissues acute stress base caveolin 1 fetal human NOS3 protein mRNA Expression novel prenatal programs promoter protein expression protein function response stressor transcription factor

项目摘要

The proposed studies are based on our previous findings that in late gestation, basal plasma Cortisol levels are normal in the long-term hypoxic (LTH) sheep fetus, while expression of key adrenal steroidogenic enzymes (P450 cholesterol side chain cleavage [CYP11A] and P450 17a-hydroxylase [CYP17]) are suppressed. Paradoxically, basal plasma adrenocorticotropin (ACTH) concentrations are elevated and, in response to a secondary stressor, Cortisol production is enhanced compared to normoxic controls. Thus, it is apparent that the fetal HPA axis has acclimatized to LTH. However, the mechanisms driving this adaptation remain to be elucidated. Nitric oxide (NO) has profound inhibitory effects on steroidogenesis in a wide range of endocrine tissues and NO synthases (NOS) are subject to regulation by hypoxia. As such NO represents a potential mechanism in the adrenocortical adaptation to LTH. The proposed studies provide a logical extension of our previous observations on HPA function in the LTH fetus and examine specific mechanisms governing the adrenocortical adaptation to LTH. This proposal will test the general hypothesis that NO (generated by eNOS) mediates the adrenocortical adaptation to LTH preserving normal basal Cortisol production in the face of this chronic stressor, and that ACTH release in response to secondary, potentially life threatening, acute stressors overcomes NO inhibition of steroidogenesis. Specific studies will define the site(s) and mechanisms via which NO inhibits steroidogenesis in LTH ovine fetal adrenal cortical cells by determining the role of S-nitrosylation of key steroidogenic enzymes (CYP11A1, CYP17) and the major transcription factor governing CYP11A1 and CYP17 expression(SF-l). Additional studies are aimed at determining the mechanisms of LTH regulation of eNOS/protein interactions (Cav-1 and Hs90) and key signaling pathways governing eNOS activity in the ovine fetal adrenal (AMPK, PI3-K/Akt, MEK/ERK1/2). Further studies will determine the mechanism(s) by which elevated ACTH levels from a secondary stress-induced release of ACTH suppresses eNOS function and the potential role of eNOS in the regulation of expression of CYP17 and CYP11A1. The proposed studies are key to furthering our understanding ofthe mechanisms of fetal adaptations to LTH.

拟议的研究基于我们之前的研究结果，即在妊娠晚期，基础血浆皮质醇长期缺氧（LTH）羊胎儿中的水平正常，而关键的肾上腺类固醇激素的表达酶（P450 胆固醇侧链裂解 [CYP11A] 和 P450 17a-羟化酶 [CYP17]）是压制。矛盾的是，基础血浆促肾上腺皮质激素 (ACTH) 浓度升高，并且在对次要压力源的反应，与含氧量正常的对照相比，皮质醇的产生有所增强。因此，它是显然，胎儿 HPA 轴已经适应了 LTH。然而，驱动这种适应的机制仍有待阐明。一氧化氮 (NO) 对多种类固醇生成具有深远的抑制作用内分泌组织和一氧化氮合酶（NOS）的功能受到缺氧的调节。因此 NO 代表肾上腺皮质适应 LTH 的潜在机制。拟议的研究提供了一个合乎逻辑的延伸我们之前对 LTH 胎儿 HPA 功能的观察并检查具体机制控制肾上腺皮质对 LTH 的适应。该提案将检验一般假设：NO （由 eNOS 产生）介导肾上腺皮质对 LTH 的适应，保持正常的基础皮质醇面对这种慢性压力源的产生，以及响应继发性的 ACTH 释放，可能危及生命的急性应激源克服了NO对类固醇生成的抑制作用。具体的研究将确定 NO 抑制 LTH 羊胎儿类固醇生成的位点和机制通过确定关键类固醇生成酶（CYP11A1、 CYP17)和控制CYP11A1和CYP17表达的主要转录因子(SF-1)。额外的研究旨在确定 LTH 调节 eNOS/蛋白质相互作用（Cav-1 和 Hs90）和控制羊胎儿肾上腺 eNOS 活性的关键信号通路（AMPK、PI3-K/Akt、 MEK/ERK1/2)。进一步的研究将确定促肾上腺皮质激素水平升高的机制。二次应激诱导的 ACTH 释放抑制 eNOS 功能以及 eNOS 在 CYP17 和 CYP11A1 表达的调节。拟议的研究对于进一步推进我们的研究至关重要了解胎儿适应 LTH 的机制。