3-NITROTYROSINE IN AGING OF SKELETAL MUSCLE AND HEART

3-硝基酪氨酸在骨骼肌和心脏老化中的作用

• 批准号: 6094056
• 负责人: Diana Jean Bigelow
• 金额: $ 30.95万
• 依托单位: UNIVERSITY OF KANSAS LAWRENCE
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-04-01 至 2004-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6094056
• 关键词: aging; calcium transporting ATPase; conformation; enzyme activity; enzyme substrate; laboratory rabbit; laboratory rat; muscle metabolism; mutant; myocardium; nitrification; oxidation reduction reaction; oxidative stress; peroxynitrites; phospholamban; protein degradation; protein isoforms; sarcoplasmic reticulum; striated muscles; tyrosine analog

DESCRIPTION: (Adapted from the Application). The long-term goal of this project is to understand the origin of the prolonged intracellular calcium transients that accompany aging of skeletal and cardiac muscle. These investigators will focus on the sarcoplasmic reticulum (SR) Ca-ATPase which mediates the rate limiting re sequestration of calcium that reestablishes resting levels of cytosolic calcium for muscle relaxation. Therefore deficits in active calcium transport by the Ca-ATPase are likely responsible for the prolonged relaxation times observed for aged cardiac and skeletal muscle. Based on their recent observations, it is hypothesized that the multiple 3-nitrotyrosine (3NY) modifications of the SERCA2a isoform of the CaATPase that accumulate in aged skeletal muscle explain these defects in contractility. The appearance of 3NY modification of SERCA2a in the aged heart suggests effects on cardiac muscle as well. 3NY modification is a characteristic indicator of peroxynitrite (ONOO-) which is formed in vivo by the diffusion-limited reaction of superoxide and nitric oxide, both produced in abundance in muscle. 3NY formation and concomitant inactivation of the Ca-ATPase can be simulated by in vitro exposure of isolated SR membranes to ONOO-. The selectivity of 3NY formation to the SERCA2a isoform of the Ca-ATPase, both in vitro and in aged skeletal muscle, to the exclusion of the highly homologous SERCA1 isoform, implicate phospholamban, which is selectively expressed with SERCA2a, as a critical factor in oxidative stress to skeletal and cardiac muscle. Therefore, the specific aims include: (1) Identify the role of phospholamban in the selective nitration of the SERCA2a isofomm of the Ca-ATPase; (2) Compare the oxidative modification of SERCA2a in the heart with that in skeletal muscle during aging; (3) Identify the functional relevance of each in vivo and in vitro 3NY site and its conformational consequences; and (4) describe the conformational features of nitrated SERCA2a that create a substrate for the denitrase activity. Delineation of pathways resulting from oxidative stress that lead to defects in calcium regulation is relevant to human health as this understanding is a prerequisite for design of effective therapies for both mitigating bass of muscle function during aging and preventing the exacerbation of myocardial damage during surgery and other therapies involving oxidative stress.

描述：(改编自应用程序)。这样做的长期目标是 项目是为了了解延长的细胞内钙离子的来源 伴随着骨骼肌和心肌老化的瞬变。这些 研究人员将重点研究肌浆网(SR)Ca-ATPase，该酶 调节重新建立的钙的限速再封存 静息状态下的细胞内钙离子水平有助于肌肉松弛。因此，赤字 在钙-ATPase的主动钙转运中可能是导致 观察到老年心肌和骨骼肌的松弛时间延长。 根据他们最近的观察，假设多个 CaATPase SERCA2a亚型的3-硝基酪氨酸(3NY)修饰 在衰老的骨骼肌中积累的蛋白质解释了这些缺陷 伸缩性。SERCA2a的3NY修饰在老年人心脏中的出现 对心肌也有影响。3NY修改是一种 过亚硝酸根(ONOO-)在体内形成的特征指示剂 超氧化物和一氧化氮的扩散受限反应，两者都产生 肌肉发达。3NY的形成和伴随的失活 CA-ATPase可通过将分离的SR膜体外暴露于 ONOO-。3NY组对SERCA2a亚型的选择性 CA-ATPase，在体外和老年骨骼肌中，排除了 高度同源的SERCA1亚型，涉及磷蛋白，这是 选择性表达SERCA2a，作为氧化应激的关键因子 骨骼肌和心肌。因此，具体目标包括：(1) 鉴定磷蛋白在SERCA2a选择性硝化中的作用 Ca-ATPase的异构体；(2)比较SERCA2a的氧化修饰 衰老过程中心脏和骨骼肌中的心脏；(3)识别 体内外各3NY位点的功能相关性及其意义 构象结果；以及(4)描述了构象特征 硝化的SERCA2a为反硝酶活性创造底物。 氧化应激导致缺陷的途径的描绘 钙调节与人类健康有关，因为这种理解是一种 设计有效的治疗方法的先决条件 衰老过程中的肌肉功能与预防心肌梗死恶化 在手术和其他涉及氧化应激的治疗中的损害。