Exercise and H2S mitigate homocysteine-mediated beta2-adrenergic receptor dysfunc

运动和 H2S 减轻同型半胱氨酸介导的 β2 肾上腺素能受体功能障碍

• 批准号: 8729004
• 负责人: Paras Kumar Mishra
• 金额: $ 36.87万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8729004
• 关键词: ATP phosphohydrolase; Ablation; Adrenergic Receptor; Affect; Agonist; Albuterol; Antihypertensive Agents; Antioxidants; Attenuated; Binding Sites; Cardiac; Cardiac Myocytes; Co-Immunoprecipitations; Complications of Diabetes Mellitus; Confocal Microscopy; Cystathionine; Devices; Diabetes Mellitus; Diabetic mouse; Diet; Echocardiography; Endoplasmic Reticulum; Enzymes; Exercise; FVB Mouse; Fatty acid glycerol esters; Fibrosis; Flow Cytometry; Functional disorder; G-Protein-Coupled Receptors; Gases; Gel; Gelatin; Gelatinase B; Glucose; Goals; Heart; Heart Contractilities; Heart Hypertrophy; Heart failure; High Pressure Liquid Chromatography; Homocysteine; Homocystine; Hydrogen Sulfide; Hyperhomocysteinemia; Hypertrophy; In Situ; Insulin; Ions; Left ventricular structure; Lyase; MMP9 gene; Measures; Mediating; Metabolic; MicroRNAs; Motivation; Mouse Strains; Mus; Muscle Cells; Muscle Contraction; Myocardial; Obese Mice; Obesity; Optics; Patients; Plasma; Plasmids; Play; Proto-Oncogene Proteins c-akt; Radio; Reporting; Role; Small Interfering RNA; Telemetry; Testing; Training; Transfection; Transgenic Organisms; Western Blotting; Western World; attenuation; diabetic; diet and exercise; glucose metabolism; improved; novel; oxidant gases; pressure; public health relevance; receptor; release of sequestered calcium ion into cytoplasm; sodium sulfide

DESCRIPTION (provided by applicant): Specific Aims: Lack of motivation to exercise is the hallmark of obesity and type2 diabetes (T2D). High fat diet (HFD) is the major cause of obesity and T2D that impair contractility of cardiomyocytes leading to heart failure. The stimulation of ¿2-adrenergic receptors (¿2-AR) induces contractility and mitigates cardiac dysfunction. Elevated level of homocysteine (Hcy) called hyperhomocysteinemia (HHcy, a co-morbid condition) is associated with heart failure in diabetes. Hcy competes with and antagonizes ¿2-AR. The long term goal of the project is to understand the role of ¿2- AR and Hcy axis in diabetes. HHcy is ameliorated by conversion of Hcy to H2S (an anti-hypertensive, vasorelaxing, and anti-oxidant gas) by cystathionine ¿ synthase (CBS) and cystathionine ? lyase (CSE). In diabetes, the levels of CBS and CSE are suppressed that induces HHcy and thereby impairs formation of H2S. H2S is an inducer of AKT (an anti-oxidant involved in glucose metabolism) and AKT is down regulated in diabetes. We have shown that H2S induces a stimulatory G-protein couple receptor called Gs (inducer of ¿2-AR) in diabetic cardiomyocytes. On the other hand, HHcy attenuates Gs. However, exercise mitigates HHcy and up regulates ¿2-AR in T2D. Also, exercise and salbutamol (¿2-AR agonist) have synergistic effect on mitigation of contractile dysfunction in diabetic cardiomyocytes. However, the underlying mechanism is unclear. We have shown that in diabetes, HHcy activates MMP9 that induces cardiac fibrosis and impairs myocardial contractility. Also, microRNA-133a (miR-133a) that regulates cardiac fibrosis and hypertrophy is attenuated in diabetic hearts. Our preliminary studies show that HHcy (CBS+/- mice) and HFD treatment attenuate myocardial ¿2-AR and miR-133a, whereas exercise and H2S mitigate this attenuation. Exercise and salbutamol have synergistic effect on induction of AKT and Gs in diabetes. The transgenic expression of ¿2-AR (¿2-ARTg) mitigates HFD induced cardiac fibrosis. Also, ablation of MMP9 gene ameliorates HFD induced contractile dysfunction. Both HFD treated WT and CBS+/- mice have left ventricle dysfunction and impaired contractility, which is mitigated by exercise training. HHcy and HFD also down regulates sarco-endoplasmic reticulum ATPase 2a (serca2a; regulates calcium flux during muscle contraction), which is improved by exercise and H2S. The central hypothesis of the proposal is that in HFD induced diabetes, the intolerance to exercise is, in part, due to attenuation of ¿2-AR and Gs by HHcy that down regulates AKT and miR-133a and induces MMP9 causing myocytes contractile dysfunction. The exercise and H2S induce ¿2-AR and Gs by mitigating HHcy and ameliorate contractile dysfunction in diabetes (Figure 1). We will test this hypothesis by following three specific aims: Specific Aim#1: To determine whether the ¿2-AR is attenuated by hyperhomocysteinemia in diabetes and exercise and H2S mitigate this attenuation. Hypothesis: In diabetes, ¿2-AR is down regulated and Hcy is elevated, and exercise and H2S induce ¿2-AR and decrease Hcy level. Specific Aim#2: To determine whether the AKT and miR-133a are attenuated and MMP9 is induced by hyperhomocysteinemia in diabetes and exercise and H2S ameliorate this attenuation and induction. Hypothesis: In diabetes, the elevated level of Hcy inhibits AKT and miR-133a and induces MMP9. Exercise and H2S induce AKT and attenuate MMP9 by decreasing Hcy level in diabetic hearts. Specific Aim#3: To determine whether the contractility of cardiomyocytes is impaired by hyperhomocysteinemia in diabetes and exercise and H2S mitigate the contractile dysfunction. Hypothesis: In diabetes, Hcy and MMP9 are elevated while ¿2-AR and AKT are attenuated leading to contractile dysfunction, and exercise and H2S ameliorate these levels and mitigate contractile dysfunction. These studies will elucidate the mechanism of homocysteine-mediated attenuation of ¿2-AR in diabetes and cardio-protective role of ¿2-AR agonist, exercise and H2S in diabetic complications.

描述（应用程序提供）：具体目的：缺乏运动动力是肥胖和2型糖尿病（T2D）的标志。高脂饮食（HFD）是肥胖和T2D的主要原因，损害了导致心力衰竭的心肌细胞的收缩力。 2-肾上腺素能受体（2AR）的刺激会诱导收缩力并减轻心脏功能障碍。升高的同型半胱氨酸水平（HCY）称为高脑结膜血症（HHCY，一种合并症）与糖尿病心力衰竭有关。 HCY竞争并与2-AR进行对抗。该项目的长期目标是了解2-AR和HCY轴在糖尿病中的作用。通过通过胱淀粉合酶（CBS）和胱氨酸氨氨酸的转化，通过将HCY转换为H2S（抗高血压，血管长和抗氧化气）来改善HHCY？裂解酶（CSE）。在糖尿病中，抑制了CBS和CSE的水平，从而诱导HHCY并损害H2S的形成。 H2S是由Akt诱导的（参与葡萄糖代谢的抗氧化剂），AKT在糖尿病中受到下调。我们已经表明，H2S在糖尿病心肌细胞中影响了一种称为GS（«2-AR诱导剂）的刺激性G蛋白夫妇受体。另一方面，HHCY减轻了GS。但是，运动减轻HHCY并在T2D中上调2-AR。此外，运动和沙丁胺醇（2-AR激动剂）对糖尿病心肌细胞的收缩功能障碍有协同作用。但是，基本机制尚不清楚。我们已经表明，在糖尿病中，HHCY激活了诱导心脏纤维化并损害心肌收缩力的MMP9。同样，调节心脏纤维化和肥大的microRNA-133A（miR-133a）在糖尿病心脏中减弱。我们的初步研究表明，HHCY（CBS +/-小鼠）和HFD治疗减弱了心肌»2-AR和MIR-133A，而运动和H2S减轻了这种衰减。运动和沙丁胺醇对糖尿病中AKT和GS的诱导具有协同作用。 2-AR（2-ARTG）的转基因表达减轻HFD诱导心脏纤维化。此外，MMP9基因的消融可以改善HFD诱导的收缩功能障碍。 HFD治疗的WT和CBS +/-小鼠均均留下心室功能障碍和收缩性受损，这可以通过运动训练来减轻。 HHCY和HFD还向下调节Sarco-肾上腺胞质ATPase 2a（SERCA2A；调节肌肉收缩期间的钙通量），这可以通过运动和H2S改善。该提案的核心假设是，在HFD诱导的糖尿病中，运动的摄入量部分是由于HHCY对2-AR和GS的衰减，从而降低了AKT和MIR-133A的调节并诱导MMP9引起肌细胞收缩功能障碍。该练习和H2S通过缓解糖尿病的HHCY和改善收缩功能障碍来诱导2-AR和GS（图1）。我们将通过以下三个特定目的来检验这一假设：具体目的＃1：确定2-AR是否因糖尿病和运动中的高脑结膜血症减弱，H2S减轻了这种衰减。假设：在糖尿病中，2-AR被调节，HCY升高，运动和H2S诱导2-AR并降低HCY水平。具体目的＃2：确定AKT和miR-133a是否被减弱，MMP9是由糖尿病和运动中的高脑结膜血症诱导的，并且H2S可以改善这种衰减和诱导。假设：在糖尿病中，升高的HCY水平抑制AKT和miR-133a和诱导MMP9。运动和H2S诱导AKT并通过降低糖尿病心脏的HCY水平来减轻MMP9。特定目的＃3：确定心肌细胞的收缩性是否受到糖尿病和运动中的高脑结膜血症的损害，H2S减轻收缩功能障碍。假设：在糖尿病中，HCY和MMP9升高，而2-AR和AKT的衰减导致收缩功能障碍，运动和H2S改善这些水平并减轻收缩功能障碍。这些研究将阐明糖尿病中2-AR的同型半胱氨酸介导的衰减的机理，以及糖尿病并发症中2-AR激动剂，运动和H2S的心脏保护作用。