Extra-nigral Neurodegeneration in Experimental Parkinson's Disease

实验性帕金森病的黑外神经变性

• 批准号: 8134324
• 负责人: NAREN L BANIK
• 金额: $ 31.44万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-20 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8134324
• 关键词: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; 1-Methyl-4-phenylpyridinium; Acute; Affect; Age; Animal Model; Animals; Antibodies; Apoptosis; Apoptotic; Astrocytes; Attenuated; Autopsy; Axon; Behavioral; Biochemical; Bradykinesia; Brain; Brain Injuries; C57BL/6 Mouse; Calcium; Calpain; Cell Death; Cell Survival; Cell membrane; Cell physiology; Cells; Cessation of life; Chronic; Data; Detection; Development; Disease Progression; Dopa; Esthesia; Etiology; Event; Experimental Models; Experimental Parkinsonism; Exposure to; Fiber; Functional disorder; Goals; Human; Immunofluorescence Immunologic; In Situ Nick-End Labeling; In Vitro; Inflammation; Inflammatory; Inflammatory Response; Interferons; Label; Lead; Levodopa; Measures; Mediating; Membrane Potentials; Microglia; Mitochondria; Modeling; Monoamine Oxidase B; Motor Neurons; Motor Pathways; Movement; Movement Disorders; Mus; Myelin; Nerve Degeneration; Neuroglia; Neurons; Neurotoxins; PTGS2 gene; Parkinson Disease; Parkinsonian Disorders; Pathogenesis; Pathology; Patients; Play; Process; Rest; Role; SJA6017; Sampling; Spinal Cord; Staining method; Stains; Substantia nigra structure; Symptoms; Techniques; Testing; Therapeutic Agents; Time; Tissues; Toxin; Tremor; Up-Regulation; axonal degeneration; base; calpain inhibitor; calpeptin; cell injury; cell type; cytochrome c; dopaminergic neuron; functional restoration; improved functioning; in vivo; insight; mitochondrial dysfunction; mouse model; myelin degeneration; neurotoxic; new therapeutic target; novel therapeutics; prevent; public health relevance; restoration; white matter; white matter change; white matter damage

DESCRIPTION (provided by applicant): Parkinson's disease (PD), a progressive degenerative movement disorder associated with loss of dopaminergic neurons in substantia nigra (SN), leads to dysfunction. The current therapy, L-dopa, does not block disease progression; therefore, new therapies must be developed. Thus, the aim is to investigate inflammatory events in brain and spinal cord (SC) and their degeneration in PD and characterize whether SC integrity and neurons are lost in PD, contributing to dysfunction. Understanding the mechanisms of damage may help develop new therapeutic strategies. While the etiology of PD is not fully understood, neurotoxins have been im- plicated in PD pathogenesis. Toxic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been extensively used as an experimental model. Since 1-methyl-4-phenylpyridinium ion (MPP+), the active toxic metabolite of MPTP, increases intracellular-free Ca2+ level and promotes mitochondrial dysfunction, a Ca2+-mediated pathology in PD has been hypothesized. Increased Ca2+ levels will promote calpain activation, increase inflammatory responses, and damage brain/SC neurons, axons, and myelin, ultimately leading to functional deficit. Our preliminary findings of direct detection of MPP+ in PD mouse SC, activation of astrocytes and microglia, and increased calpain activity and expression in neurons indicate that SC is also affected. These findings were corroborated by preliminary data showing motoneurons from SC of PD patients are also damaged. MPP+ treatment of ventral SC motor neuron cells (VSC4.1) showed increased intracellular [Ca2+] and calpain activity with loss of membrane potential and death while calpain inhibitors (calpeptin, SJA6017) protected and restored cell function. From these findings, we hypothesize that, since SC coordinates movement and sensation of the body, damage to SC neurons, axons, and myelin, in addition to SN, may be an important factor in PD, and calpain plays a crucial role in this dysfunction by promoting inflammation and cell death and may be a target for therapy. Three specific aims will test the hypotheses. Specific Aim 1 will investigate whether MPTP is directly converted into MPP+ in SC, enters through the degenerating axons from brain, or a combination of both; examine the effects of MPTP (MPP+) on SN and SC neurons and white matter in acute and chronic parkinsonism; assess calpain expression and activity and subsequent inflammation and cell damage; and examine the status of neurons, axons, and myelin in SC of postmortem PD patients. Specific Aim 2 will explore the effects of neurotoxic MPP+ in differentiated VSC4.1 cells and test the neuroprotective efficacy of calpain inhibitors in vitro employing electrophysiological technique. Specific Aim 3 will examine whether calpain inhibitor treatment will attenuate inflammation, prevent apoptosis of brain and SC neurons, protect cells, preserve axons and myelin, and improve function in MPTP-induced PD mice. These studies will delineate the role of calpain in inflammation and neurodegeneration in MPTP-induced PD and the probable neuroprotective efficacy of calpain inhibitors in PD as therapeutic agents. PUBLIC HEALTH RELEVANCE: Since the spinal cord coordinates movement and sensation of the body, damage to spinal cord neurons, in addition to the substantia nigra (brain), and alteration in white matter integrity (i.e., axonal and myelin degeneration) as well as loss of myelin-forming cells may be important factors in Parkinson's disease (PD), and calpain could play a crucial role in this dysfunction. This study will examine the role of calpain in cell and axon damage in the progression of disease in an animal model, the efficacy of calpain inhibitor as a therapeutic agent in vivo and in vitro, and the status of neurons in post-mortem PD tissue. Delineating a role for calpain in the progression of disease could potentially lead to new therapeutic targets since the most potent therapy, L-dopa, does not block the progression of Parkinson's disease.

描述（由申请人提供）：帕金森氏病（PD），这是一种逐渐退行性运动障碍，与底胺（SN）中多巴胺能神经元的丧失有关，导致功能障碍。当前的疗法L-DOPA不会阻止疾病进展。因此，必须开发新的疗法。因此，目的是研究大脑和脊髓（SC）中的炎症事件及其在PD中的变性，并表征SC完整性和神经元是否在PD中丢失，导致功能障碍。了解损害的机制可能有助于制定新的治疗策略。虽然PD的病因尚未完全了解，但神经毒素已在PD发病机理中得到了影响。有毒1-甲基-4-苯基1,2,3,6-四氢吡啶（MPTP）已被广泛用作实验模型。由于1-甲基-4-苯基吡啶离子（MPP+）（MPPP的活性毒性代谢产物）增加了无细胞内Ca2+水平并促进线粒体功能障碍，因此已经推测了PD中Ca2+介导的病理学。 Ca2+水平的升高将促进钙蛋白酶的激活，增加炎症反应以及损害脑/SC神经元，轴突和髓磷脂，最终导致功能不足。我们在PD小鼠SC中直接检测MPP+的初步发现，星形胶质细胞和小胶质细胞的激活以及神经元中的钙蛋白酶活性和表达增加表明SC也受到影响。这些发现通过初步数据证实了这些发现，表明PD患者SC的运动神经元也受损。 MPP+腹侧SC运动神经元细胞（VSC4.1）的治疗显示出细胞内[Ca2+]和钙蛋白酶活性增加，而膜电位和死亡的丧失，而钙蛋白酶抑制剂（Calpeptin，SJA6017）受到保护并恢复细胞功能。从这些发现中，我们假设，由于SC会辅化身体的运动和感觉，因此SC神经元，轴突和髓磷脂的损害可能是PD的重要因素，Calpain在这种功能障碍中起着至关重要的因素，通过促进炎症和细胞死亡，可以促进炎症和细胞死亡，并且可能是治疗的靶点。三个具体目标将检验假设。具体目标1将研究MPTP是否直接转化为SC中的MPP+，通过大脑的退化轴突或两者的组合进入。检查MPTP（MPP+）对急性和慢性帕金森氏症中SN和SC神经元以及白质的影响；评估钙蛋白酶的表达和活性以及随后的炎症和细胞损伤；并检查神经元，轴突和髓磷脂的状态在验尸PD患者的SC中。具体目标2将探索神经毒性MPP+在分化的VSC4.1细胞中的作用，并测试使用电生理技术在体外测试钙蛋白酶抑制剂的神经保护功效。具体目标3将检查钙蛋白酶抑制剂治疗是否会减轻炎症，防止脑和SC神经元凋亡，保护细胞，保存轴突和髓磷脂，并改善MPTP诱导的PD小鼠的功能。这些研究将描述钙蛋白酶在MPTP诱导的PD中的炎症和神经变性中的作用，以及Calpain抑制剂在PD作为治疗剂中的神经保护功效。 公共卫生相关性：由于脊髓对身体的运动和感觉，对脊髓神经元的损害，脊髓神经元的损害以及白质完整性（即轴突和髓磷脂退化）的变化以及髓磷脂细胞的变化以及骨髓蛋白细胞的丧失可能是帕克森病（Parkinson Dise）的重要因素（PARTIN）和CALUN（PAIR）和CARPAIR（PARN），并且可能会扮演这个cruce crouct and crouct。这项研究将研究钙蛋白酶在动物模型中疾病进展，钙蛋白酶抑制剂作为体内和体外治疗剂的功效以及神经元在验尸PD组织中的状态的作用。描述钙蛋白酶在疾病进展中的作用可能会导致新的治疗靶标，因为最有效的疗法L-DOPA不会阻止帕金森氏病的进展。