Role of Astrocyte Mitochondria in Neurotoxicity

星形胶质细胞线粒体在神经毒性中的作用

• 批准号: 6625820
• 负责人: MARTIN A. PHILBERT
• 金额: $ 36.98万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-06-01 至 2006-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6625820
• 关键词: BCL2 gene /protein; Bax gene /protein; acid base balance; astrocytes; bioenergetics; calcium ion; confocal scanning microscopy; electron microscopy; gene expression; gene targeting; genetically modified animals; immunocytochemistry; laboratory mouse; light microscopy; membrane potentials; mitochondria; nanotechnology; neurons; neurotoxicology; nitrobenzene; oxidative stress; potassium ion; protein structure function; sodium ion; tissue /cell culture; toxin metabolism; western blottings

DESCRIPTION (provided by applicant): 1,3-Dinitrobenzene (DNB) induces a selective, focal edematous lesion in the brainstem astrocytes of rats reminiscent of lesions induced by vitamin B, deficiency and chemicals that produce central nervous system (CNS) energy deprivation syndromes. Preliminary data collected in our laboratories provide compelling evidence that selective regional astrocyte vulnerability to DNB is mediated by opening of the mitochondrial permeability transition pore (mt-PTP) with subsequent formation of reactive oxygen species (ROS). It is well established in the literature that the mt-PTP is stabilized in the closed conformation by Bc1-2 and BC1-XL and maintained in the open state by Bax. The central hypothesis of this proposal is that regional expression of Bc1-2 family molecules regulates the differential susceptibility of astrocytes to chemicals that induce oxidative stress. Addressing the following specific questions will test the hypothesis: 1) Does DNB induce translocation of Bax to astrocytic mitochondria? 2) Does modulation of expression of mt-PTP agonist (Bax) or antagonist (Bc1-2/Bcl-XL) proteins alter the toxicity of DNB in astrocytes? 3) Does alteration of the expression of Bax, Bc1-2 or BC1 XL proteins modulate astrocytic sensitivity in vivo? 4) Does DNB induce transient regional inhibition of SDH in neurons and astrocytes in vivo and in vitro, and is the inhibition of SDH linked to induction of the mt-PTP? 5) Does opening of the mt-PTP increase cellular calcium loads thereby altering the ability of cortical and brainstem astrocytes to spatially buffer physiologic ions and maintain cell volume and viability? The Specific Aims will address the functional consequences of altered expression of selected Bc1-2 family proteins and their translocation to the mitochondrial compartment. Enriched primary cortical and brainstem astrocyte cultures will be used as a well characterized in vitro model of DNB-induced encephalopathy. These studies utilize emerging techniques in real-time confocal and high-resolution laser scanning confocal microscopy developed in the laboratory of the PI and collaborators. The recent development of nano-optochemical sensing technology in our laboratories permits a degree of spatial resolution and quantitative measurement of ionic transients hitherto unavailable. Data obtained from the proposed studies will provide a greater understanding of molecular and pathophysiologic mechanisms underlying the selective vulnerability of neuron and astrocyte populations to neurotoxicants and neurodegenerative change.

描述（由申请人提供）：1，3-二硝基苯（DNB）诱导 大鼠脑干星形胶质细胞选择性局灶性水肿性损伤 让人想起由维生素B缺乏和化学物质引起的病变， 产生中枢神经系统（CNS）能量剥夺综合征。初步 我们实验室收集的数据提供了令人信服的证据， 局部星形胶质细胞对DNB的脆弱性是通过开放 线粒体通透性转换孔（mt-PTP），随后形成 活性氧（ROS）在文献中已经确立， mt-PTP被Bc 1 -2和BC 1-XL稳定在闭合构象， 由Bax维持在开放状态。这一提议的核心假设是 Bc 1 -2家族分子的区域表达调节了 星形胶质细胞对诱导氧化应激的化学物质的敏感性。 回答以下具体问题将检验这一假设： 1)DNB是否诱导Bax易位到星形胶质细胞线粒体？ 2)调节mt-PTP激动剂（Bax）或拮抗剂的表达 （Bc 1 -2/Bcl-XL）蛋白改变DNB对星形胶质细胞的毒性？ 3)Bax、Bc 1 -2或BC 1 XL蛋白表达的改变是否调节了 星形胶质细胞在体内的敏感性？ 4)DNB是否引起神经元SDH的短暂区域抑制， 星形胶质细胞在体内和体外，是抑制SDH连接到 诱导mt-PTP？ 5)线粒体PTP的开放是否增加了细胞钙负荷，从而改变了 皮质和脑干星形胶质细胞空间缓冲能力 生理离子和维持细胞体积和活力？ 具体目标将解决改变的功能后果， 选择的Bc 1 -2家族蛋白质的表达及其易位到 线粒体区室富集的原代皮质和脑干星形胶质细胞 培养物将用作DNB诱导的良好表征的体外模型。 脑病这些研究利用新兴技术，在实时共聚焦 和高分辨率激光扫描共聚焦显微镜， PI和合作者的实验室。的最新发展 纳米光化学传感技术在我们的实验室允许一定程度的 迄今为止离子瞬变空间分辨率和定量测量 不可用.从拟议的研究中获得的数据将提供更大的 了解潜在的分子和病理生理机制， 神经元和星形胶质细胞群体对神经毒物的选择性脆弱性 和神经退行性变化。