Ang II and Overnutrition and Insulin resistance in Cardiovascular Tissue

血管紧张素II与心血管组织营养过剩和胰岛素抵抗

• 批准号: 8255506
• 负责人: James Russell Sowers
• 金额: $ 37.35万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-11 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8255506
• 关键词: 1-Phosphatidylinositol 3-Kinase; Address; Adult; American; Angiotensin II; Animals; Attenuated; Binding; Biological; Blood Glucose; Blood Pressure; Blood Vessels; Blood flow; C57BL/6 Mouse; Carbohydrates; Cardiac; Cardiac Myocytes; Cardiovascular Diseases; Cardiovascular Physiology; Cardiovascular system; Cells; Chronic; Comorbidity; Coronary; Data; Development; Diabetes Mellitus; Diet; Dietary Fats; Dietary Sucrose; Disease; Docking; Dose; Endothelial Cells; Euglycemic Clamping; Event; Exposure to; Fatty acid glycerol esters; Functional disorder; Glucose; Glucose Clamp; Hormones; Hypertension; Image; Imaging Device; Impairment; In Vitro; Inflammation; Insulin; Insulin Receptor; Insulin Resistance; Intake; Knock-out; Laboratories; Lead; Link; Liver; Mass Spectrum Analysis; Measures; Mediating; Metabolic; Modeling; Molecular; Mus; Myocardial; Myocardium; Nitric Oxide; Non-Insulin-Dependent Diabetes Mellitus; Nutrient; Obesity; Overnutrition; Overweight; Pathway interactions; Persons; Phosphorylation; Phosphotransferases; Positron-Emission Tomography; Prevalence; Production; Protein-Serine-Threonine Kinases; Proteins; Proto-Oncogene Proteins c-akt; Receptor Inhibition; Receptor, Angiotensin, Type 1; Relaxation; Renin-Angiotensin System; Research; Resistance; Ribosomal Protein S6 Kinase; Rodent; Rodent Model; Role; Serine; Signal Pathway; Signal Transduction; Site; Skeletal Muscle; Small Interfering RNA; Smooth Muscle Myocytes; Sucrose; Telemetry; Tissues; Tyrosine; Vascular Endothelial Cell; Vasodilation; Western Blotting; Work; animal tissue; cohort; db/db mouse; glucose metabolism; glucose transport; glucose uptake; in vivo; innovation; insulin receptor substrate 1 protein; insulin sensitivity; insulin signaling; mTOR protein; novel; nutrition; olmesartan; prevent; public health relevance; receptor; response; sensor; skeletal; therapeutic target

DESCRIPTION (provided by applicant): Diminished insulin (INS) sensitivity is a common feature of disease states such as obesity, hypertension and diabetes. Over-nutrition (especially that characterized by excess intake of fat and carbohydrates) is a major factor in the increased prevalence of hypertension and diabetes. These co-morbidities may be driven by a decrease in INS-mediated vasorelaxation and glucose transport in cardiovascular (CV) and skeletal muscle tissue. In addition to over-nutrition, several other mechanisms, such as enhanced activation of the renin- angiotensin-system (RAS), inflammation, and associated abnormalities in INS metabolic signaling, may help explain the linkage between INS resistance and hypertension. There is emerging evidence that over-nutrition and angiotensin II (ANG II) may promote INS resistance through the mammalian target of rapamycin (mTOR)/S6 kinase 1 (S6K1) signaling pathway. mTOR, a highly conserved nutrient sensor, modulates INS metabolic signaling through its phosphorylation (P) of S6K1, an evolutionarily conserved serine (Ser) kinase. Evidence is mounting that chronic activation of S6K1, by excessive nutrients, promotes INS resistance in fat, liver and skeletal muscle tissue through increased Ser (P) of the critical INS signaling/docking molecule, INS receptor substrate protein 1 (IRS-1), leading to impaired phosphoinositol 3 kinase (PI3-K) engagement and protein kinase B (Akt) stimulation. Our recent work indicates that S6K1 is activated by ANG II in CV tissue leading to diminished INS metabolic signaling and biological consequences, such as impaired nitric oxide (NO)-mediated vascular relaxation. This proposal seeks to investigate novel molecular mechanisms by which ANG II and over-nutrition individually and collectively promote INS resistance in CV and skeletal muscle tissue. To evaluate the CV functional effects of INS metabolic signaling, we will utilize our state of the art rodent imaging center. In the INS resistant state, myocardial and skeletal muscle glucose uptake and metabolism is impaired, leading to diastolic dysfunction, attenuated myocardial and skeletal muscle blood flow, and impaired ischemic reconditioning. We have shown that both impaired INS stimulated glucose uptake and diastolic dysfunction are related to impaired systemic and myocardial INS metabolic signaling in models of obesity and increased tissue RAS expression. For this proposal, we will utilize novel knockout and knockdown strategies, as well as innovative rodent imaging tools, to evaluate the impact of increased S6K1 signaling (ANG II and/or excess nutrients) on myocardial function and coronary and skeletal microvascular blood flow responses to INS metabolic signaling. To address Aim 1, we will examine the relationship between ANG II and S6K1 activation and INS signaling in primary cultured endothelial cells, vascular smooth muscle cells and cardiomyocytes. Metabolic signaling results will be correlated to functional measures including NO production, cardiomyocyte glucose transport and diastolic relaxation. To further explore the collective, as well as the independent, roles of ANG II and over-nutrition on S6K1, Aim 2 will focus on in vivo/ex vivo effects in the S6K1-/- and C57BL/6 mice treated with ANG II that produces a slow pressor response and/or a high fat (60%) and high sucrose (20%) diet. A cohort of animals will be treated with an AT1R blocker (olmesartan) at a dose of 0.5 mg/kg/day, a dose determined by telemetry to have no effect on blood pressure in db/db mice. INS resistance will be assessed by hyperinsulinemic, euglycemic clamp, cardiac PET scanning, ex vivo IRS-1 (P) and INS metabolic signaling, and glucose uptake in heart and skeletal muscle. Finally, in vivo INS mediated skeletal muscle arteriolar and ex vivo coronary arteriolar, NO induced relaxation, and in vivo cardiac glucose uptake and diastolic relaxation will be related to ex vivo S6K1 activity and IRS-1 site specific Ser vs. Tyr (P) and the resultant downstream IRS-1/PI3-K/Akt signaling. PUBLIC HEALTH RELEVANCE: Insulin is critical for normal cardiovascular function as well as 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 type 2 diabetes mellitus 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 this abnormity. A better understanding of factors involved in insulin resistance should help in the development of therapeutic targets to help prevent diabetes and cardiovascular disease.

描述（由申请人提供）：胰岛素（INS）敏感性降低是肥胖，高血压和糖尿病等疾病状态的共同特征。过度营养（尤其是脂肪和碳水化合物过多的特征）是高血压和糖尿病患病率增加的主要因素。这些合并症可能是由心血管（CV）和骨骼肌组织中的介导的血管瘤和葡萄糖转运的减少驱动的。除了过度营养外，其他几种机制，例如增强了肾上腺素 - 血管紧张素系统（RAS）的激活，炎症和INS代谢信号中相关的异常，可能有助于解释INS耐药性和高血压之间的联系。有新兴的证据表明，过度营养和血管紧张素II（ANG II）可以通过雷帕霉素（MTOR）/S6激酶1（S6K1）信号传导途径的哺乳动物靶标促进INS抗性。 MTOR是一种高度保守的营养传感器，通过其S6K1的磷酸化（P）（一种进化保守的丝氨酸（SER）激酶）调节INS代谢信号传导。有证据表明，通过过量营养，S6K1的慢性激活通过临界INS信号传导/对接分子的Ser（P）促进脂肪，肝脏和骨骼肌组织的INS耐药性导致磷酸肌醇3激酶（PI3-K）参与度受损和蛋白激酶B（AKT）刺激。我们最近的工作表明，S6K1在CV组织中被ANG II激活，导致INS代谢信号和生物学后果减少，例如一氧化氮（NO）介导的血管弛豫。该提案旨在研究新的分子机制，通过这种机制，ANG II和过度整体单独并共同促进了CV和骨骼肌组织中的INS耐药性。为了评估INS代谢信号传导的CV功能效应，我们将利用我们最先进的啮齿动物成像中心。在INS抗性状态下，心肌和骨骼肌葡萄糖摄取和代谢受损，导致舒张功能障碍，减弱心肌和骨骼肌血液流动以及缺血性再现。我们已经表明，在肥胖模型和组织RAS表达增加的系统性和心肌INS代谢信号传导和组织RAS表达增加的系统性和心肌INS代谢信号传导中，受损的INS刺激葡萄糖摄取和舒张功能障碍都与受损的系统性和心肌INS相关。为此，我们将利用新颖的淘汰和敲除策略以及创新的啮齿动物成像工具来评估增加S6K1信号传导（ANG II和/或多余的营养素）对心肌功能以及冠状动脉以及冠状动脉和骨骼微血管血流流动的影响INS代谢信号。为了解决目标1，我们将研究ANG II与S6K1激活与INS信号之间的关系，而原代内皮细胞，血管平滑肌细胞和心肌细胞之间的关系。代谢信号结果将与功能措施相关，包括无生产，心肌细胞葡萄糖转运和舒张期松弛。为了进一步探索ANG II和过度营养在S6K1上的集体以及独立的角色，AIM 2将重点放在S6K1 - / - 和C57BL/6小鼠中的体内/Ex Vivo效应上产生缓慢的压力反应和/或高脂肪（60％）和高蔗糖（20％）饮食。一组动物将以0.5 mg/kg/天的剂量用AT1R阻滞剂（Olmesartan）处理，该剂量通过遥测确定的剂量对DB/DB小鼠的血压没有影响。 INS耐药性将通过高胰岛素，电子糖症夹，心脏PET扫描，EX VIVO IRS-1（P）和INS代谢信号传导以及心脏和骨骼肌中的葡萄糖摄取来评估。最后，体内介导的骨骼肌小动脉和外体冠状动脉动脉，没有诱导的放松，并且体内心脏葡萄糖的摄取和舒张性放松将与EX VIVO S6K1活性以及IRS-1站点特定的Servs vs. Tyr（P）和Tyr（P）和特定于IRS-1站点有关最终的下游IRS-1/PI3-K/AKT信号传导。 公共卫生相关性：胰岛素对于正常的心血管功能以及维持正常的血糖水平至关重要。胰岛素正常代谢作用的组织耐药性通常存在于患有高血压的人中，并且是2型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种异常。对胰岛素抵抗涉及的因素的更好理解应有助于发展治疗靶标，以帮助预防糖尿病和心血管疾病。