Role of inflammation in manganese-induced neurotoxicity

炎症在锰诱导的神经毒性中的作用

• 批准号: 6478019
• 负责人: NIKOLAY M FILIPOV
• 金额: $ 10.69万
• 依托单位: MISSISSIPPI STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-27 至 2005-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6478019
• 关键词: basal ganglia; biological signal transduction; cytokine; environmental contamination; immunocytochemistry; inflammation; laboratory mouse; manganese; metal poisoning; methylphenyltetrahydropyridine; microglia; neural degeneration; neuroimmunomodulation; neurotoxicology; neurotoxins; nitric oxide; nitric oxide synthase; substantia nigra; tissue /cell culture; western blottings

DESCRIPTION (provided by applicant) Studies suggest that environmental contaminants, include manganese (Mn), may contribute to Idiopathic Parkinson?s Disease (IPD), but the etiology of this disease still remains elusive. Two major sources of Mn pollution in the United States arise from the reintroduction of the fuel additive methylcyclopentadienyl manganese tricarbonyl and the widespread use of Mn-containing fungicides (maneb). Recently, the investigators obtained evidence that Mn, a neurotokicant causing Parkinson?s Disease-like symptoms, increases proinflammatory cytokines and nitric oxide production by activated microglia in vitro. These findings suggest that (i) inflammation plays a role in Mn-induced neurotoxicity, and (ii) Mn exposure may be a contributing factor (via enhanced production of inflammatory mediators) to IPD. The research proposed here will explore these possibilities utilizing both in vitro and in vivo approaches. Additional studies will begin to delineate the mechanism(s) by, which Mn enhances the inflammatory response in the brain. It is hypothesized that exposure to Mn, enhances activation of microglia which are disproportionately distributed in the brain and as a result, over-production of proinflammatory cytokines and nitric oxide occurs with the final outcome being selective neuronal loss in the basal ganglia. Furthermore, exposure to Mn in the context of an inflammatory stimulus would potentiate the dopaminergic neuronal damage in the 1-methyl-4-phenyl-1,2,3,4- tetrahydropyridline (MPTP) mouse model of PD. Microglial cell line (N9), as well as primary microglia, will be used to determine whether Mn speciation plays a role in the increased inflammatory response. Microglial (N9)-dopaminergic (PC 12) cell line co-cultures, as well as mesencephalic primary cultures will be used in vitro studies and the effects of Mn in the presence of a microglial activator (endotoxin, LPS) on neuronal cell death will be assessed. Additionally, Mn influence on the sensitivity of the dopaminergic neurons to MPTP under the same in vitro conditions will be evaluated. C57BL/6 (MPTP-sensitive) and CD-1 (MPTP-resistant) mice will be used for in vivo studies and animals will be treated similarly to the cell cultures in the in vitro studies. After short (14 days) exposure to Mn, some animals will be challenged with MPTP, and the degree of basal ganglia damage, as well as microglial activation will be assessed. Successful completion of the proposed research will help revealing the role of inflammation in Mn neurotoxicity and, more importantly, establish a mechanism by which environmental contaminants may contribute to the etiology of IPD. The long-term goal of the proposed studies is to understand the role of microglia and environmental contaminants in neurodegenerative diseases.

描述（由申请人提供） 研究表明，包括锰 (Mn) 在内的环境污染物可能会导致特发性帕金森病 (IPD)，但这种疾病的病因仍然难以捉摸。美国锰污染的两个主要来源是燃料添加剂甲基环戊二烯基三羰基锰的重新引入和广泛使用 含锰杀菌剂（代森锰）。最近，研究人员获得的证据表明，锰（一种引起帕金森病样症状的神经镇静剂）在体外可增加促炎细胞因子和激活小胶质细胞产生的一氧化氮。这些发现表明 (i) 炎症在锰诱导的神经毒性中发挥作用，(ii) 锰暴露可能是 IPD 的一个促成因素（通过增强炎症介质的产生）。这里提出的研究将利用体外和体内方法探索这些可能性。其他研究将开始阐明锰增强大脑炎症反应的机制。据推测，接触锰会增强小胶质细胞的活化，而小胶质细胞是 不成比例地分布在大脑中，导致促炎细胞因子和一氧化氮的过度产生，最终结果是基底神经节选择性神经元损失。此外，在炎症刺激的情况下接触锰会增强 1-甲基-4-苯基-1,2,3,4-四氢吡啶啉 (MPTP) 小鼠 PD 模型中的多巴胺能神经元损伤。小胶质细胞系 (N9) 以及原代小胶质细胞将用于确定锰形态是否在炎症反应增强中发挥作用。小胶质细胞 (N9)-多巴胺能 (PC 12) 细胞系共培养物以及中脑原代培养物将用于体外研究，并且在小胶质细胞激活剂（内毒素，LPS）存在下 Mn 对神经元细胞死亡的影响将进行评估。此外，将评估在相同的体外条件下Mn对多巴胺能神经元对MPTP敏感性的影响。 C57BL/6（MPTP 敏感）和 CD-1（MPTP 抗性）小鼠将用于体内研究，动物将接受与体内细胞培养物类似的处理。 体外研究。短暂（14 天）接触 Mn 后，一些动物将受到 MPTP 的攻击，并评估基底神经节损伤的程度以及小胶质细胞的活化。成功完成拟议的研究将有助于揭示炎症在锰神经毒性中的作用，更重要的是，建立环境污染物可能导致 IPD 病因的机制。拟议的长期目标 研究的目的是了解小胶质细胞和环境污染物在神经退行性疾病中的作用。