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

• 批准号: 8015757
• 负责人: Charles A Ducsay
• 金额: $ 20.19万
• 依托单位: LOMA LINDA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8015757
• 关键词: Acute; Address; Adrenal Cortex; Adrenal Glands; Adult; Altitude; Automobile Driving; CYP11A1 gene; CYP17A1 gene; Cattle; Cells; Cholesterol; Chronic; Chronic stress; Clinical; Corticotropin; Cysteine; Cytochrome P450; DNA Binding; Development; Disease; Endocrine; Enzymes; Face; Fetal Growth; Fetal Growth Retardation; Fetus; Free Radicals; Gene Targeting; Growth and Development function; Heat-Shock Proteins 90; Heme; Hydrocortisone; Hypoxia; Laboratories; Life; Long-Term Effects; 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; fetus cell; human NOS3 protein; novel; prenatal; programs; promoter; protein expression; protein function; response; stressor; transcription factor

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.

这项研究是基于我们以前的发现，即在妊娠晚期，基础血浆皮质醇 水平是正常的长期缺氧（LTH）羊胎儿，而表达的关键肾上腺类固醇激素 酶（P450胆固醇侧链裂解[CYP 11 A]和P450 17 α-羟化酶[CYP 17]）是 抑制特别是，基础血浆促肾上腺皮质激素（ACTH）浓度升高， 作为对二次应激的响应，与含氧量正常的对照相比，皮质醇产生增强。照经上所 显然胎儿HPA轴已适应LTH。然而，驱动这种适应的机制 仍有待阐明。一氧化氮（NO）在很大程度上抑制类固醇激素的合成 缺氧对内分泌组织和一氧化氮合酶（NOS）的活性有调节作用。因此，NO代表 肾上腺皮质对LTH适应的一种潜在机制。这些研究提供了一个逻辑 扩展了我们以前对LTH胎儿HPA功能的观察，并研究了具体机制 控制肾上腺皮质对LTH的适应。这一建议将检验一般假设，即没有 （由eNOS产生）介导肾上腺皮质对LTH的适应，保留正常的基础皮质醇 在面对这种慢性应激源时，ACTH的产生，以及ACTH的释放， 潜在地威胁生命的急性应激源克服了NO对类固醇生成的抑制。具体 研究将确定NO抑制LTH绵羊胎儿类固醇生成的位点和机制 通过测定关键类固醇生成酶（CYP 11 A1， CYP 17）和控制CYP 11 A1和CYP 17表达的主要转录因子（SF-1）。额外 研究旨在确定eNOS/蛋白质相互作用的LTH调节机制（Cav-1和Cav-2）。 Hs 90）和控制绵羊胎儿肾上腺中eNOS活性的关键信号通路（AMPK，PI 3-K/Akt， MEK/ERK 1/2）。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释放抑制了eNOS的功能，eNOS在应激中的潜在作用 CYP 17和CYP 11 A1表达的调节。建议的研究是进一步推动我们 了解胎儿适应LTH的机制。