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（由申请人提供）： 具体目标：缺乏运动动力是肥胖和 2 型糖尿病 (T2D) 的标志。高脂肪饮食 (HFD) 是肥胖和 T2D 的主要原因，会损害心肌细胞的收缩性，导致心力衰竭。 . 的刺激 ¿ 2-肾上腺素能受体 (¿2-AR) 可诱导收缩性并减轻心脏功能障碍。同型半胱氨酸 (Hcy) 水平升高，称为高同型半胱氨酸血症（HHcy，一种共病），与糖尿病心力衰竭相关并与之竞争并拮抗。 ¿ 2-AR。该项目的长期目标是了解 ¿ 的作用。 2- 糖尿病中的 AR 和 Hcy 轴通过胱硫醚将 Hcy 转化为 H2S（一种抗高血压、舒血管和抗氧化气体）来改善。合酶 (CBS) 和胱硫醚裂解酶 (CSE) 在糖尿病中，CBS 和 CSE 的水平受到抑制，从而诱导 HHcy，从而损害 H2S 的形成，H2S 是 AKT（参与葡萄糖代谢的抗氧化剂）的诱导剂。我们已经证明，H2S 会诱导一种称为 Gs（¿2-AR 诱导剂）的刺激性 G 蛋白偶联受体。另一方面，在糖尿病心肌细胞中，HHcy 会减弱 Gs。然而，运动会减轻 HHcy 并上调 ¿ T2D 中的 2-AR 此外，运动和沙丁胺醇（¿2-AR 激动剂）对缓解糖尿病心肌细胞的收缩功能障碍具有协同作用，但我们已经表明，在糖尿病中，HHcy 会激活 MMP9。心脏纤维化并损害心肌收缩力，此外，microRNA-133a (miR-133a) 还可调节心脏纤维化和肥厚。我们的初步研究表明，HHcy（CBS+/- 小鼠）和 HFD 治疗可减弱心肌 ¿ 2-AR 和 miR-133a，而运动和 H2S 可以减轻这种减弱作用。运动和沙丁胺醇对糖尿病中 AKT 和 Gs 的转基因表达具有协同作用。 2-AR (¿2-ARTg) 可减轻 HFD 诱导的心脏纤维化，此外，消融 MMP9 基因还可改善 HFD 诱导的收缩功能障碍。 HHcy 和 HFD 还下调肌内质网 ATP 酶 2a（serca2a；调节肌肉运动过程中的钙通量）该提案的中心假设是，在 HFD 诱发的糖尿病中，对运动的不耐受部分是由于 ¿ 的减弱。 HHcy 的 2-AR 和 Gs 下调 AKT 和 miR-133a 并诱导 MMP9，导致心肌细胞收缩功能障碍。运动和 H2S 会诱导 ¿ 2-AR 和 Gs 通过减轻 HHcy 和改善糖尿病患者的收缩功能障碍（图 1）我们将通过以下三个具体目标来检验这一假设： 具体目标#1：确定 ¿ 2-AR 会因糖尿病和运动中的高同型半胱氨酸血症而减弱，而 H2S 会减轻这种减弱。 假设：在糖尿病中，¿ 2-AR 下调且 Hcy 升高，运动和 H2S 诱发 ¿ 2-AR 并降低 Hcy 水平。具体目标#2：确定糖尿病和运动中的高同型半胱氨酸血症是否会减弱 AKT 和 miR-133a，并且 H2S 会改善这种减弱和诱导。假设：在糖尿病中，水平升高。 Hcy 抑制 AKT 和 miR-133a 并诱导 MMP9。运动和 H2S 诱导 AKT 并减弱。通过降低糖尿病心脏中的 Hcy 水平来降低 MMP9。 具体目标#3：确定糖尿病和运动中的高同型半胱氨酸血症是否会损害心肌细胞的收缩力，并且 H2S 会减轻收缩功能障碍。 假设：在糖尿病中，Hcy 和 MMP9 升高，而 ¿ 2-AR 和 AKT 减弱，导致收缩功能障碍，运动和 H2S 可以改善这些水平并减轻收缩功能障碍。这些研究将阐明同型半胱氨酸介导的 ¿ 2-AR在糖尿病和心脏保护中的作用 ¿ 2-AR 激动剂、运动和 H2S 在糖尿病并发症中的作用。