Arginase and Regulation of Nitric Oxide Synthase in ALS

ALS 中精氨酸酶和一氧化氮合酶的调节

• 批准号: 6530047
• 负责人: RAJIV R RATAN
• 金额: $ 43.21万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-15 至 2005-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6530047
• 关键词: amyotrophic lateral sclerosis; apoptosis; arginase; arginine; cell type; cytoprotection; enzyme activity; enzyme induction /repression; genetically modified animals; isozymes; laboratory mouse; neural degeneration; neuroprotectants; neurotoxins; nitric oxide; nitric oxide synthase; oxidative stress; protein localization; superoxide dismutase

DESCRIPTION (Adapted from applicant's abstract): Amyotrophic lateral sclerosis is a prevalent neurological disorder characterized by inexorable muscle weakness leading to death. The principal pathological finding in amyotrophic lateral sclerosis is loss of nerve cells in the anterior horns of the spinal cord, the motor nuclei of the brainstem, and the upper motor neurons of the cerebral cortex. Investigations aimed at preventing or limiting progression of amyotrophic lateral sclerosis have thus focused on the mechanisms by which neurons degenerate. A transgenic mouse model has been developed that possesses many of the pathological and clinical features of human familial and sporadic amyotrophic lateral sclerosis. As nitric oxide (NO) has been shown to mediate neuronal loss in other neurodegenerative conditions, several groups have investigated the role that NO may play in disease progression | in the transgenic model. The results have been conflicting likely because currently available inhibitors of nitric oxide synthase do not permit optimal control of NO generation within particular cell types and subcellular compartments. A novel potential strategy for regulating nitric oxide synthesis involves the enzyme arginase that can | regulate availability of arginine in the cytoplasm or mitochondria. In preliminary studies, we have shown that: 1) extracellular arginase blocks neuronal apoptosis and 2) arginase immunoreactivity is, upregulated in the spinal cord of ALS transgenic mice as well as humans with the sporadic and familial forms of amyotrophic lateral sclerosis. These preliminary results lead to the overall hypothesis to be tested in this proposal: about Interventions aimed at promoting arginase activities in microglia, astrocytes and/or motor neurons will limit availability of cell arginine for toxic NO generation and thereby diminish cell death and disease progression in amyotrophic lateral sclerosis but permit NO to, mediate its survival promoting effects in each of these cell types. We propose to test this hypothesis by: 1) determining the cell types and subcellular compartments where arginase is expressed in the normal central nervous system of humans and mice, and how the localization and levels of these isoforms change in amyotrophic lateral sclerosis as well as in a transgenic mouse! Model of amyotrophic lateral sclerosis and how this compares to the localization of NOS (all forms) in these tissues; and 2) determining whether increased arginase activity in microglia, astrocytes or neurons from control mice or mice over expressing SOD1 mutant (G93A) will abrogate NO mediated toxicity of motor neurons induced by growth factor deprivation, excitotoxins or LPS/IFN-gamma treatment. These studies promise to enhance our understanding of how arginine about metabolism, including the synthesis of NO, is regulated in the normal and abnormal nervous system.

描述（改编自申请人的摘要）：肌萎缩性侧面硬化症是一种普遍的神经系统疾病，其特征是肌肉不可分割 导致死亡的弱点。肌萎缩症的主要病理发现 侧硬化是脊柱前角中神经细胞的丧失 绳索，脑干的运动核和上部运动神经元的上部运动神经元 大脑皮层。旨在防止或限制进展的调查 肌萎缩性侧索硬化症因此重点是 神经元退化。已经开发了具有的转基因小鼠模型 人类家族和零星的许多病理和临床特征 肌萎缩性侧硬化症。由于一氧化氮（NO）已显示用于介导 在其他神经退行性疾病中的神经元丧失，几组具有 研究了没有可能在疾病进展中起作用的作用|在 转基因模型。结果可能是矛盾的，因为目前 一氧化氮合酶的可用抑制剂不允许对 在特定的细胞类型和亚细胞隔室中没有产生。一个 调节一氧化氮合成的新型潜在策略涉及 可以|调节精氨酸在细胞质中的可用性 或线粒体。在初步研究中，我们表明：1）细胞外 精氨酸酶阻断神经元凋亡和2）精氨酸酶免疫反应性是 在ALS转基因小鼠的脊髓以及人类中上调 肌萎缩性侧硬化症的零星和家族形式。这些 初步结果导致总体假设在此中进行检验 提案：旨在促进精氨酸酶活性的干预措施 小胶质细胞，星形胶质细胞和/或运动神经元将限制细胞的可用性 精氨酸的有毒无产生，从而减少细胞死亡和疾病 肌萎缩性侧索硬化症的进展，但允许不介导其介导 这些细胞类型中的每一种生存促进效应。我们建议对此进行测试 假设由：1）确定细胞类型和亚细胞室其中 精氨酸酶在人类和小鼠的正常中枢神经系统中表达， 以及这些同工型的定位和水平如何变化 横向硬化症以及转基因小鼠！肌萎缩的模型 横向硬化以及与NOS的定位（所有形式）相比 在这些组织中； 2）确定精氨酸酶活性是否增加 来自对照小鼠或小鼠的小胶质细胞，星形胶质细胞或神经元表达SOD1 突变体（G93A）将不清除诱导的运动神经元的介导的毒性 生长因子剥夺，兴奋毒素或LPS/IFN-gamma治疗。这些 研究有望增强我们对精氨酸如何对代谢的理解， 包括NO的合成，在正常和异常神经中受到调节 系统。