HORMONE REGULATION OF CARDIAC INJURY

心脏损伤的激素调节

• 批准号: 7381200
• 负责人: Eric J Smart
• 金额: $ 25.05万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7381200
• 关键词: HORMONE; REGULATION; CARDIAC; INJURY

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The central hypothesis of this proposal is that HDL-associated sex hormones (estrogen and testosterone) regulate the activity of cardiac myocyte constitutive nitric oxide synthase which subsequently affects the extent of ischemic injury. Epidemiological studies demonstrate that women are less prone to ischemic heart disease than men. The mechanisms responsible the differences in ischemic injury observed between men and women are not know although the current focus is on sex hormones, in particular estrogen and testosterone. A large number of studies have implicated estrogen-induced stimulation of constitutive nitric oxide synthase (cNOS) as providing protection against ischemic injury of cardiac myocytes. The role of testosterone is unclear with reports of protection against ischemic injury and reports of testosterone promoting ischemic injury. The majority of the studies on estrogen and testosterone do not distinguish between effects mediated by the endothelium in hearts and cardiac myocytes. One of the novel aspects of the proposed studies is that the preliminary data indicate that estrogen and testosterone have direct effects on cardiac myocytes, independent of the endothelium. Another novel aspect of the proposed studies is that it is estrogen or testosterone associated with HDL that is responsible for the generation of nitric oxide in cardiac myocytes and protection/promotion of ischemic injury. The molecular mechanism whereby estrogen limits ischemic injury and testosterone increases ischemic injury will be tested in two Aims. Aim 1: To determine the mechanism whereby HDL-associated estrogen stimulates the production of nitric oxide and limits ischemic injury. The preliminary studies suggest that estrogen receptor alpha and caveolin-1 form a complex that stimulates cNOS via AMP kinase. Cardiac myocytes isolated from wild type mice, caveolin-1 null mice, or estrogen receptor alpha null mice will be used along with dominant negative adenoviral constructs, agonist/antagonists, and enzyme assays to dissect the mechanism(s). In addition, wild type mice, SR-BI null mice, caveolin-1 null mice, and estrogen receptor alpha null mice along with ovariectomies and ovariectomies/estrogen replacement will be used to determine the effect on ischemic injury. Aim 2: To determine the mechanism whereby HDL-associated testosterone decreases the generation of nitric oxide and increases ischemic injury. The preliminary studies demonstrate that HDL-associated testosterone decreases the generation of nitric oxide without affecting the cellular levels of cNOS. Isolated cardiac myocytes will be used to examine several possible mechanisms for the HDL-testosterone mediated inhibition of cNOS such as, altered caveolin binding to cNOS, depletion of caveolae cholesterol, re-localization of cNOS, and modification of cNOS and/or caveolin-1. Additional studies will determine if the androgen receptor and/or testosterone uptake are involved in this process. Wild type mice, SR-BI null mice, and caveolin-1 null mice along with orchidectomies and orchidectomies/testosterone replacement will be used to determine the effect on ischemic injury.

该子项目是利用 NIH/NCRR 资助的中心拨款提供的资源的众多研究子项目之一。子项目和研究者 (PI) 可能已从另一个 NIH 来源获得主要资金，因此可以在其他 CRISP 条目中出现。列出的机构是中心的机构，不一定是研究者的机构。该提议的中心假设是，HDL 相关性激素（雌激素和睾酮）调节心肌细胞组成型一氧化氮合酶的活性，从而影响缺血性损伤的程度。 流行病学研究表明，女性比男性更不易患缺血性心脏病。尽管目前的焦点是性激素，特别是雌激素和睾酮，但导致男性和女性之间观察到的缺血性损伤差异的机制尚不清楚。大量研究表明，雌激素诱导的组成型一氧化氮合酶 (cNOS) 刺激可提供针对心肌细胞缺血性损伤的保护作用。睾酮的作用尚不清楚，有报道称睾酮可预防缺血性损伤，也有报道称睾酮可促进缺血性损伤。大多数关于雌激素和睾酮的研究没有区分心脏和心肌细胞内皮细胞介导的作用。拟议研究的新颖之处之一是初步数据表明雌激素和睾酮对心肌细胞有直接影响，独立于内皮细胞。拟议研究的另一个新颖之处是，与 HDL 相关的雌激素或睾酮负责心肌细胞中一氧化氮的生成并保护/促进缺血性损伤。雌激素限制缺血性损伤和睾酮增加缺血性损伤的分子机制将在两个目标中进行测试。 目标 1：确定 HDL 相关雌激素刺激一氧化氮产生并限制缺血性损伤的机制。初步研究表明，雌激素受体 α 和 Caveolin-1 形成复合物，通过 AMP 激酶刺激 cNOS。从野生型小鼠、caveolin-1 缺失小鼠或雌激素受体 α 缺失小鼠中分离的心肌细胞将与显性失活腺病毒构建体、激动剂/拮抗剂和酶测定一起使用以剖析机制。此外，野生型小鼠、SR-BI无效小鼠、caveolin-1无效小鼠和雌激素受体α无效小鼠以及卵巢切除术和卵巢切除术/雌激素替代将用于确定对缺血性损伤的影响。 目标 2：确定 HDL 相关睾酮减少一氧化氮生成并增加缺血性损伤的机制。初步研究表明，HDL 相关睾酮可减少一氧化氮的产生，而不影响细胞中 cNOS 的水平。分离的心肌细胞将用于检查 HDL-睾酮介导的 cNOS 抑制的几种可能机制，例如改变小窝蛋白与 cNOS 的结合、小窝胆固醇的消耗、cNOS 的重新定位以及 cNOS 和/或 Caveolin-1 的修饰。其他研究将确定雄激素受体和/或睾酮摄取是否参与该过程。野生型小鼠、SR-BI无效小鼠和caveolin-1无效小鼠以及睾丸切除术和睾丸切除术/睾酮替代将用于确定对缺血性损伤的影响。