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）的主要特征。最近的研究表明，糖尿病和高血压患者的胰岛素抵抗的发病机制和心血管并发症中肾素-血管紧张素-醛固酮系统（RAAS）的增强以及相关的氧化应激增强。我们认为丝氨酸 (Ser) 激酶信号通路的激活与活性氧 (ROS) 的过量产生相结合，构成了血管紧张素 II (Ang II) 和醛固酮导致心血管组织胰岛素抵抗的机制之一。在我们的初步调查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抵抗的潜在重要介质。主要在脂肪和骨骼肌组织中进行的研究表明，包括 ROK 在内的多种 Ser 激酶可能通过诱导关键对接蛋白胰岛素受体底物 1 (IRS-1) 的位点特异性 Ser 磷酸化来抑制胰岛素代谢信号。因此，我们假设氧化还原敏感性 ROK 的 RAAS 激活通过在心血管组织中引起定点 IRS-1 Ser 磷酸化来抑制胰岛素介导的 IRS-1/PI3-K/Akt 信号传导。这一假设的推论是，长期暴露于过量的 RAAS 会激活 ROS/ROK 通路，由于 ROK 诱导 IRS-1 的位点特异性 Ser 磷酸化，导致血管舒张、心肌葡萄糖利用和舒张舒张受损。在我们提出的研究中，我们计划使用质谱和其他新技术来研究 IRS-1 的位点特异性 Ser 和酪氨酸 (Tyr) 磷酸化与 Ang II 和醛固酮诱导的胰岛素抵抗的关系。 ROK 在介导胰岛素抵抗中的作用将在原代培养细胞中进行研究，并在长期过量暴露于 Ang II 和/或醛固酮（有或没有 Ang II 和盐皮质激素受体阻断）的啮齿类动物的心血管组织中进行体内/离体研究和ROK抑制。为了实现具体目标 1，我们将在用 Ang II、醛固酮或两者预处理的细胞中使用针对两种 ROK 亚型的 siRNA 以及 ROS/ROK 信号传导的化学抑制剂，然后测量原代培养的大鼠内皮细胞对胰岛素的代谢和功能反应、血管平滑肌和心肌细胞。在具体目标 2 中，我们将通过体内和离体测定慢性 Ang II 和/或醛固酮暴露对心脏、脉管系统和骨骼肌中胰岛素/IRS-1 途径代谢信号的影响。我们将利用我们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）扫描来评估胰岛素刺激的心脏葡萄糖摄取，并使用电影磁共振成像来评估胰岛素敏感的心脏舒张舒张。我们还将使用视频显微镜直接观察骨骼肌小动脉，以评估胰岛素诱导的一氧化氮依赖性血管舒张。共同研究人员包括一名成像物理学家、一名血管生物学家和一名质谱专家，以评估 IRS-1 对接蛋白的位点特异性 Ser 和 Tyr 磷酸化。我们提出的研究应该提供有关血管紧张素II和/或醛固酮共同和单独作用的机制的新信息，在高血压和糖尿病等胰岛素抵抗的情况下，导致胰岛素代谢信号受损和心血管功能受损。这项研究应该揭示新的治疗策略，可以预防与高血压和糖尿病患者 RAAS 升高相关的 IRS-1 过度 Ser 磷酸化。总结 胰岛素对于正常心血管功能以及维持正常血糖水平至关重要。高血压患者通常存在对胰岛素正常代谢作用的组织抵抗，这是糖尿病和心血管疾病的先兆。心血管组织和骨骼肌中胰岛素抵抗的基本机制尚不清楚，我们提出的工作旨在阐明这些机制。更好地了解与胰岛素抵抗相关的因素应该能够开发出有助于预防糖尿病和心血管疾病的治疗靶点。