CATECHOLAMINES, ANTIOXIDANTS AND OXIDATIVE STRESS

儿茶酚胺、抗氧化剂和氧化应激

• 批准号: 6195399
• 负责人: KANDATEGE WIMALASENA
• 金额: $ 24.17万
• 依托单位: WICHITA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2004-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6195399
• 关键词: ascorbate; catecholamines; cytotoxicity; dopamine beta monooxygenase; enzyme mechanism; free radical oxygen; free radical scavengers; hydrogen transporting ATP synthase; isozymes; membrane transport proteins; neuronal transport; neuroprotectants; neurotoxins; neurotransmitter metabolism; nutrition related tag; oxidative stress; protein protein interaction; synaptic vesicles; vitamin biosynthesis

Easily autooxidizable catecholamines are known to generate reactive radicals and H2O2 under aerobic conditions due to their inherent redox properties. Consequently, catecholaminergic neurons are inherently subjected to high oxidative stress and free radical damage. The degneration of catecholaminergic neurons in aging and central nervous system diseases such as Parkinson's Disease, as well as in the use of illicit drugs such as amphetamines have been attributed to the catecholamine mediated excessive production of oxygen free radicals and/or H2O2 in the affected areas of the brain. Although, most of the reactive radical species and oxidants are effectively scavenged by enzymatic defense mechanisms and by cellular oxidants, their excessive generation may lead to extensive cellular damage. Presence of high concentrations of ascorbate (Asc), an intricate ATPase drive, b561-mediated, Asc regenerating system (ARS), and an efficient catecholamine uptake mechanism together with the absence of antioxidants such as glutathione in catecholamine storage vesicles suggest that, in addition to providing electrons for dopamine beta-monooxygenase (DbetaM) and peptidyl alpha- hydroxylating monooxygenase (PHM) reactions, Asc must also play a key role in the protection of catecholaminergic neurons from catecholamine induced free radical damage. Therefore, the malfunctioning of proton translocating ATPase, ARS, or monoamine transporter could result in high oxidative stress leading to an exponentially propagating cascade of radical generation and extensive cellular damage. Despite this convincing evidence, the biochemical mechanisms that my integrate the pathological features in catecholaminergic neurons have not been fully explored. Thus, a more precise description of (a) the biochemical steps in catecholamine metabolism and (b) the role of antioxidants in protecting catecholamines from oxidation, consequently relieving oxidative stress could be a significant advancement in our understanding of the dysfunction of catecholaminergic neurons. The overall objective of the proposed studies is to examine the functional coupling of the monoamine transporter, proton translocating ATPase, ARS, and DbetaM at the molecular level using multidisciplinary approaches using chromaffin granules and granule ghosts as a model. With a better understanding of the functional coupling of these proteins, the role of these proteins in protecting catecholamine storage vesicles from oxidative stress as well as the effect of oxidative stress on their individual and coordinated functions will be examined.

由于其固有的氧化还原特性，容易自动氧化的儿茶酚胺在有氧条件下会产生反应自由基和 H2O2。 因此，儿茶酚胺能神经元本质上受到高氧化应激和自由基损伤。 衰老和中枢神经系统疾病（例如帕金森氏病）以及使用非法药物（例如安非他明）中儿茶酚胺能神经元的退化归因于儿茶酚胺介导受影响区域中氧自由基和/或 H2O2 的过量产生大脑的。 尽管大多数活性自由基和氧化剂可以被酶防御机制和细胞氧化剂有效清除，但它们的过量产生可能会导致广泛的细胞损伤。高浓度的抗坏血酸 (Asc)、复杂的 ATP 酶驱动、b561 介导的 Asc 再生系统 (ARS) 和有效的儿茶酚胺摄取机制以及儿茶酚胺储存囊泡中不存在谷胱甘肽等抗氧化剂表明，为多巴胺β-单加氧酶（DbetaM）和肽基α-羟基化单加氧酶提供电子(PHM) 反应中，Asc 还必须在保护儿茶酚胺能神经元免受儿茶酚胺诱导的自由基损伤中发挥关键作用。 因此，质子转位 ATP 酶、ARS 或单胺转运蛋白的故障可能会导致高氧化应激，从而导致自由基生成的指数级联级传播和广泛的细胞损伤。 尽管有这些令人信服的证据，但整合儿茶酚胺能神经元病理特征的生化机制尚未得到充分探索。 因此，更准确地描述（a）儿茶酚胺代谢中的生化步骤和（b）抗氧化剂在保护儿茶酚胺免遭氧化中的作用，从而缓解氧化应激可能是我们对儿茶酚胺能神经元功能障碍的理解的重大进步。 拟议研究的总体目标是使用嗜铬颗粒和颗粒鬼作为模型，采用多学科方法在分子水平上检查单胺转运蛋白、质子转位 ATP 酶、ARS 和 DbetaM 的功能耦合。 随着对这些蛋白质的功能耦合的更好理解，将检查这些蛋白质在保护儿茶酚胺储存囊泡免受氧化应激中的作用以及氧化应激对其个体和协调功能的影响。