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（由申请方提供）：帕金森病（PD）是一种与黑质（SN）多巴胺能神经元丢失相关的进行性退行性运动障碍，可导致功能障碍。目前的治疗方法，左旋多巴，不能阻止疾病的进展;因此，必须开发新的治疗方法。因此，目的是研究脑和脊髓（SC）中的炎症事件及其在PD中的变性，并表征PD中SC完整性和神经元是否丢失，从而导致功能障碍。了解损伤的机制可能有助于开发新的治疗策略。虽然PD的病因尚未完全清楚，但神经毒素在PD发病机制中已被阐明。有毒的1-甲基-4-苯基-1，2，3，6-四氢吡啶（MPTP）被广泛用作实验模型。由于MPTP的活性毒性代谢产物1-甲基-4-苯基吡啶离子（MPP+）增加细胞内游离Ca 2+水平并促进线粒体功能障碍，因此已经假设PD中的Ca 2+介导的病理学。增加的Ca 2+水平将促进钙蛋白酶激活，增加炎症反应，并损伤脑/SC神经元、轴突和髓鞘，最终导致功能缺陷。我们对PD小鼠SC中MPP+的直接检测、星形胶质细胞和小胶质细胞的活化以及神经元中钙蛋白酶活性和表达的增加的初步发现表明SC也受到影响。这些发现得到了初步数据的证实，初步数据显示PD患者SC的运动神经元也受损。MPP+处理腹侧SC运动神经元细胞（VSC 4.1）显示细胞内[Ca 2 +]和钙蛋白酶活性增加，伴随膜电位损失和死亡，而钙蛋白酶抑制剂（钙肽酶，SJA 6017）保护和恢复细胞功能。从这些发现中，我们假设，由于SC协调身体的运动和感觉，除了SN之外，SC神经元、轴突和髓鞘的损伤可能是PD的重要因素，钙蛋白酶通过促进炎症和细胞死亡在这种功能障碍中起着至关重要的作用，并且可能是治疗的靶点。三个具体目标将检验这些假设。具体目标1将研究MPTP是否在SC中直接转化为MPP+，通过变性轴突从大脑进入，或两者的组合;检查MPTP（MPP+）对急性和慢性帕金森病中SN和SC神经元和白色物质的影响;评估钙蛋白酶表达和活性以及随后的炎症和细胞损伤;并检查PD患者死后SC中神经元、轴突和髓鞘的状态。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，并采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神经元的凋亡，保护细胞，保护轴突和髓鞘，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炎症和神经变性中的作用，以及钙蛋白酶抑制剂作为治疗剂在PD中的可能神经保护功效。 公共卫生相关性：由于脊髓协调身体的运动和感觉，除了黑质（脑）之外，脊髓神经元的损伤以及白色物质完整性的改变（即，轴突和髓鞘变性）以及髓鞘形成细胞的丢失可能是帕金森病（PD）的重要因素，钙蛋白酶可能在这种功能障碍中起关键作用。本研究将研究钙蛋白酶在动物模型中疾病进展中细胞和轴突损伤中的作用，钙蛋白酶抑制剂作为体内和体外治疗剂的功效，以及死后PD组织中神经元的状态。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点，因为最有效的治疗方法左旋多巴不能阻止帕金森病的进展。