Extra-nigral Neurodegeneration in Experimental Parkinson's Disease

实验性帕金森病的黑外神经变性

基本信息

批准号：
7783503
负责人：
NAREN L BANIK
金额：
$ 33.12万
依托单位：
MEDICAL UNIVERSITY OF SOUTH CAROLINA
依托单位国家：
美国
项目类别：
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/7783503
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 Label Lead Levodopa Measures Mediating Membrane Potentials Microglia Mitochondria Modeling Monoamine Oxidase B Motor Neurons Motor Pathways Movement Movement Disorders Mus Muscle Rigidity 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 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

项目摘要

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）：帕金森病（PD）是一种进行性退行性运动障碍，与黑质（SN）中多巴胺能神经元的丧失相关，导致功能障碍。目前的治疗方法是左旋多巴，不能阻止疾病进展；因此，必须开发新的疗法。因此，目的是研究脑和脊髓 (SC) 中的炎症事件及其在 PD 中的退化，并表征 SC 完整性和神经元是否在 PD 中丢失，从而导致功能障碍。了解损伤机制可能有助于开发新的治疗策略。虽然帕金森病的病因尚不完全清楚，但神经毒素与帕金森病的发病机制有关。有毒的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-苯基吡啶鎓离子 (MPP+)（MPTP 的活性毒性代谢物）会增加细胞内游离 Ca2+ 水平并促进线粒体功能障碍，因此推测 PD 中存在 Ca2+ 介导的病理学。 Ca2+ 水平升高会促进钙蛋白酶激活，增加炎症反应，并损害大脑/SC 神经元、轴突和髓磷脂，最终导致功能缺陷。我们在 PD 小鼠 SC 中直接检测 MPP+、星形胶质细胞和小胶质细胞的激活以及神经元中钙蛋白酶活性和表达增加的初步结果表明 SC 也受到影响。初步数据证实了这些发现，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 (VSC4.1) 显示细胞内 [Ca2+] 和钙蛋白酶活性增加，并伴有膜电位丧失和死亡，而钙蛋白酶抑制剂（钙肽、SJA6017）保护和恢复细胞功能。根据这些发现，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、轴突和髓磷脂的损伤可能是 PD 的一个重要因素，而钙蛋白酶在这种功能障碍中起着至关重要的作用通过促进炎症和细胞死亡，可能是治疗的目标。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+，通过大脑退化轴突进入，还是两者的组合；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PD患者死后SC中神经元、轴突和髓磷脂的状态。具体目标2将探讨神经毒性MPP+对分化的VSC4.1细胞的影响，并利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、防止大脑和 SC 神经元凋亡、保护细胞、保留轴突和髓磷脂并改善 MPTP 诱导的 PD 小鼠的功能。这些研究将阐明钙蛋白酶在 MPTP 诱导的帕金森病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帕金森病中可能的神经保护功效。公共健康相关性：由于脊髓协调身体的运动和感觉，除了黑质（大脑）之外，还会对脊髓神经元造成损害，白质完整性发生改变（即轴突和髓磷脂变性）以及丧失髓磷脂形成细胞的减少可能是帕金森病 (PD) 的重要因素，而钙蛋白酶可能在这种功能障碍中发挥关键作用。本研究将研究钙蛋白酶在动物模型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，以及死后帕金森病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带来新的治疗靶点，因为最有效的疗法左旋多巴并不能阻止帕金森病的进展。