Role of Astrocyte Mitochondria in Neurotoxicity

描述(申请人提供)：1，3-二硝基苯(DNB)诱导 大鼠脑干星形胶质细胞的选择性水肿性损害 让人想起维生素B、缺乏和化学物质引起的损伤 产生中枢神经系统(CNS)能量剥夺综合症。初步 我们实验室收集的数据提供了令人信服的证据 星形胶质细胞对DNB的易感性是通过开放 线粒体通透性转换孔(mt-PTP)伴后续形成 活性氧(ROS)的含量。在文学作品中已经很好地确立了 MT-PTP由Bc1-2和Bc1-xl稳定在闭合构象中， 由BAX保持打开状态。这项提议的中心假设是 Bc1-2家族分子的区域表达调节分化 星形胶质细胞对引起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转位到星形细胞线粒体？ 2)mt-PTP激动剂(Bax)或拮抗剂的表达是否有调节作用 (bc1-2/bc1-xl)蛋白改变DNB对星形胶质细胞的毒性？ 3)Bax、Bc1-2或Bc1XL蛋白表达的改变是否调节 星形细胞对活体的敏感性？ 4)DNB是否诱导神经元SDH的一过性区域抑制和 星形胶质细胞在体内和体外，与SDH的抑制有关 Mt-PTP的诱导？ 5)mt-ptp的开放是否增加了细胞的钙负荷，从而改变了 大脑皮质和脑干星形胶质细胞的空间缓冲能力 生理离子和维持细胞体积和活力？ 具体目标将解决更改后的功能后果 精选Bc1-2家族蛋白的表达及其转位 线粒体室。富含原代皮质和脑干星形胶质细胞 培养物可作为DNB诱导的体外模型。 脑病。这些研究利用了实时共聚焦的新兴技术 和高分辨率激光扫描共聚焦显微镜是在 PI及其合作者的实验室。的最新发展 我们实验室的纳米光化学传感技术在一定程度上允许 迄今离子瞬变的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 了解其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易感性 和神经退行性改变。

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.