Ang II and Aldosterone Effects on Insulin Resistance in Cardiovascular Tissue

血管紧张素II和醛固酮对心血管组织胰岛素抵抗的影响

• 批准号: 8034321
• 负责人: James Russell Sowers
• 金额: $ 31.5万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8034321
• 关键词: 1-Phosphatidylinositol 3-Kinase; Address; Aldosterone; Angiotensin II; Animal Model; Animals; Attenuated; Binding; Blood Glucose; Blood Vessels; Cardiac; Cardiac Myocytes; Cardiovascular Diseases; Cardiovascular Physiology; Cardiovascular system; Cells; Chemicals; Chronic; Cine Magnetic Resonance Imaging; Data; Development; Diabetes Mellitus; Disease; Docking; Endothelial Cells; Event; Exposure to; Fatty acid glycerol esters; Generations; Glucose; Growth; Health; Heart; Hypertension; Image; Imagery; Impairment; In Vitro; Insulin; Insulin Receptor; Insulin Resistance; Investigation; Laboratories; Lead; Link; Mass Spectrum Analysis; Measures; Mediating; Mediator of activation protein; Metabolic; Mineralocorticoid Receptor; Myocardial; Nitric Oxide; Non-Insulin-Dependent Diabetes Mellitus; Oxidases; Oxidation-Reduction; Oxidative Stress; Pathogenesis; Pathway interactions; Persons; Phosphorylation; Positron-Emission Tomography; Primary Cell Cultures; Protein Isoforms; Protein-Serine-Threonine Kinases; Proteins; Proto-Oncogene Proteins c-akt; Rattus; Reactive Oxygen Species; Receptor, Angiotensin, Type 1; Relaxation; Renin-Angiotensin-Aldosterone System; Research; Research Personnel; Resistance; Rho-associated kinase; Rodent; Rodent Model; Role; Serine; Signal Pathway; Signal Transduction; Site; Skeletal Muscle; Small Interfering RNA; Smooth Muscle Myocytes; Somatomedins; Surface; Techniques; Tissues; Transgenic Organisms; Tyrosine; Tyrosine Phosphorylation; Vascular Endothelial Cell; Vascular Smooth Muscle; Vasodilation; Video Microscopy; Western Blotting; Work; animal tissue; arteriole; glucose uptake; in vivo; inhibitor/antagonist; insulin receptor substrate 1 protein; insulin sensitivity; insulin signaling; non-genomic; novel; novel therapeutics; prevent; receptor; response; stress-activated protein kinase 1; therapeutic target

DESCRIPTION (provided by applicant): Decreased insulin sensitivity is a cardinal feature of various pathological conditions such as type 2 diabetes and hypertension. Recent research has implicated a heightened renin-angiotensin-aldosterone system (RAAS) and associated enhanced oxidative stress in the pathogenesis and cardiovascular complications of insulin resistance in people with diabetes and hypertension. We posit that activation of serine (Ser) kinase signaling pathways, in conjunction with excess generation of reactive oxygen species (ROS), constitute one of the mechanisms whereby angiotensin II (Ang II) and aldosterone contribute to insulin resistance in cardiovascular tissue. In our preliminary investigation, as well as in work from other laboratories, the redox-sensitive Ser kinase Rho kinase (ROK), has surfaced as a potentially important mediator of Ang II and aldosterone induced insulin resistance. Research, primarily conducted in fat and skeletal muscle tissue, indicates that several Ser kinases, including ROK, may inhibit insulin metabolic signaling by inducing site specific Ser phosphorylation of the critical docking protein insulin receptor substrate-1 (IRS-1). Accordingly, we hypothesize that RAAS activation of redox sensitive ROK inhibits insulin mediated IRS- 1/PI3-K/Akt signaling by causing site directed IRS-1 Ser phosphorylation in cardiovascular tissue. A corollary to this hypothesis is that chronic exposure to excess RAAS activates ROS/ROK pathways leading to impairment of vasorelaxation, myocardial glucose utilization and diastolic relaxation because of ROK induced site-specific Ser phosphorylation of IRS-1. In our proposed research, we plan to use mass spectroscopy and other novel techniques to investigate site specific Ser and tyrosine (Tyr) phosphorylation of IRS-1 in relation to Ang II and aldosterone induced insulin resistance. The role of ROK in mediating insulin resistance will be investigated in primary cultured cells and in vivo/ex vivo studies in cardiovascular tissues of rodents with excess long-term exposure to Ang II and/or aldosterone, with and without Ang II and mineralocorticoid receptor blockade, and ROK inhibition. To address Specific Aim 1, we will employ siRNA for the two ROK isoforms as well as chemical inhibitors of ROS/ROK signaling in cells pretreated with Ang II, aldosterone, or both, before measuring metabolic and functional responses to insulin in primary cultured rat endothelial, vascular smooth muscle and cardiomyocyte cells. In Specific Aim 2, we will conduct both in vivo and ex vivo determination of the impact of chronic Ang II and/or aldosterone exposure on metabolic signaling through the insulin/IRS-1 pathway in heart, vasculature and skeletal muscle. We will utilize our state of the art rodent imaging center to conduct critical in vivo investigations, employ positron emission tomography (PET) scanning to evaluate insulin stimulated glucose uptake in the heart, and cine-magnetic resonance imaging to evaluate insulin sensitive cardiac diastolic relaxation. We will also employ direct visualization of skeletal muscle arterioles using video microscopy to evaluate insulin induced nitric oxide dependent vasodilation. Co-investigators include an imaging physicist, a vascular biologist and an expert in mass spectroscopy to evaluate site specific Ser and Tyr phosphorylation of the IRS-1 docking protein. Our proposed investigation should provide novel information on the mechanisms by which Ang II and/or aldosterone, acting collectively and individually, contribute to impaired insulin metabolic signaling and compromised cardiovascular function in conditions of insulin resistance such as hypertension and diabetes. This research should uncover new therapeutic strategies that can prevent excessive Ser phosphorylation of IRS-1 associated with a heightened RAAS in persons with hypertension and diabetes. Lay Summary Insulin is critical for normal cardiovascular function as well as for maintaining normal blood glucose levels. Tissue resistance to the normal metabolic actions of insulin is often present in persons with hypertension, and is a precursor for diabetes and cardiovascular disease. The fundamental mechanisms underlying insulin resistance in cardiovascular tissue, as well as skeletal muscle, are not well understood, and our proposed work is directed at elucidation of these mechanisms. A better understanding of factors involved in insulin resistance should enable development of therapeutic targets to help prevent diabetes and cardiovascular disease.

描述（由申请人提供）：胰岛素敏感性降低是各种病理状况（例如2型糖尿病和高血压）的基本特征。最近的研究表明，在糖尿病和高血压患者中，胰岛素抵抗的发病机理和心血管并发性增强了肾素 - 血管紧张素 - 醛固酮系统（RAAS）以及相关的增强氧化应激。我们认为，丝氨酸（SER）激酶信号通路的激活以及过量产生活性氧（ROS）构成了血管紧张素II（ANG II）和醛固酮在心血管组织中有助于胰岛素抵抗的机制之一。在我们的初步研究以及其他实验室的工作中，氧化还原敏感的Ser激酶Rho激酶（ROK）已成为ANG II和醛固酮诱导的胰岛素耐药性的潜在重要介体。主要在脂肪和骨骼肌组织中进行的研究表明，包括ROK在内的几种SER激酶可能通过诱导位点特异性SER磷酸化来抑制胰岛素代谢信号传导，对关键的停靠蛋白胰岛素受体底物-1（IRS-1）。因此，我们假设RAAS激活氧化还原敏感的ROK会抑制胰岛素介导的IRS-1/PI3-K/AKT信号传导，从而引起位点定向在心血管组织中的IRS-1 Ser磷酸化。这一假设的推论是，由于ROK引起的IRS-1的位点特异性Ser磷酸化，因此长期暴露于过量RAA会激活ROS/ROK途径，导致血管长期损害，心肌葡萄糖利用和舒张性松弛。在我们提出的研究中，我们计划使用质谱和其他新型技术来研究IRS-1与ANG II和醛固酮诱导的胰岛素耐药性相关的IRS-1特异性SER和酪氨酸（Tyr）磷酸化。 ROK在介导胰岛素抵抗中的作用将在原代培养细胞和体内/外体内研究中研究在过度长期暴露于ANG II和/或醛固酮的啮齿动物的心血管组织中，并且有和没有ANG II和矿物质皮质受体阻断和ROK抑制。为了解决特定目标1，我们将在用ANG II，醛固酮或两者兼而有之的细胞中的两个ROK同工型以及ROS/ROK信号传导的化学抑制剂，然后在测量对原代培养的大鼠内皮，血管平滑肌和心肌细胞中胰岛素的代谢和功能反应。在特定的目标2中，我们将通过心脏，脉管系统和骨骼肌的胰岛素/IRS-1途径进行体内和离体测定慢性ANG II和/或醛固酮暴露对代谢信号的影响。我们将利用我们的最先进的啮齿动物成像中心进行关键的体内研究，采用正电子发射断层扫描（PET）扫描来评估心脏中胰岛素刺激的葡萄糖摄取，并评估胰岛素敏感的心脏敏感性心动敏感性心动敏感性。我们还将使用视频显微镜直接使用骨骼肌动脉的可视化，以评估胰岛素诱导的一氧化氮依赖性血管舒张。共同研究器包括一名成像物理学家，一名血管生物学家以及质谱专家，以评估IRS-1对接蛋白的位点特异性Ser和Tyr磷酸化。我们提出的研究应提供有关ANG II和/或醛固酮在胰岛素抵抗（例如高血压和糖尿病）的胰岛素抵抗条件下，ANG II和/或醛固酮统称和单独起作用的机制的新信息。这项研究应揭示新的治疗策略，以防止与高血压和糖尿病患者相关的IRS-1磷酸化过度磷酸化。 LIE摘要胰岛素对于正常的心血管功能以及维持正常血糖水平至关重要。胰岛素正常代谢作用的组织耐药性通常存在于高血压的人体中，并且是糖尿病和心血管疾病的前体。心血管组织中胰岛素抵抗以及骨骼肌的基本机制尚不清楚，我们提出的工作旨在阐明这些机制。对胰岛素抵抗涉及的因素的更好理解应能够发展出治疗靶标，以帮助预防糖尿病和心血管疾病。