The Role of Gliotransmission in Cerebral Ischemia

胶质细胞传输在脑缺血中的作用

• 批准号: 8071506
• 负责人: Shinghua Ding
• 金额: $ 31.41万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-15 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8071506
• 关键词: Accounting; Acute; Astrocytes; Biological; Biological Assay; Biology; Brain; Brain Injuries; Brain Ischemia; Cells; Cerebral Ischemia; Cessation of life; Disease; Electrophysiology (science); Exhibits; Frequencies; Functional disorder; Glutamates; Goals; Health; Histocytochemistry; Human; Image; Immunohistochemistry; Injury; Intervention; Ischemia; Knowledge; Magnetic Resonance Imaging; Mediating; Microdialysis; Microscopy; Molecular; Molecular Genetics; Mus; N-Methyl-D-Aspartate Receptors; NR2B NMDA receptor; Nature; Nerve Degeneration; Neuroglia; Neurons; Pathogenesis; Pathway interactions; Peripheral; Pharmacological Treatment; Phospholipase C; Physiological; Property; Public Health; Regulation; Relative (related person); Role; Signal Pathway; Signal Transduction; Staging; Stroke; Synapses; Technology; Testing; Therapeutic; Transgenic Mice; Viral; Work; astrogliosis; base; excitotoxicity; experience; extracellular; in vivo; insight; mouse model; nervous system disorder; neuronal excitability; new therapeutic target; novel; public health relevance; response; tripolyphosphate; two-photon; virtual

DESCRIPTION (provided by applicant): As a leading neurological disorder, acute cerebral ischemia accounts for approximately 80% of all human strokes and has a major impact on public health. Understanding the pathophysiology is essential to develop therapeutic avenues to minimize brain damage. Thus, the project goal is to determine the novel role of astrocytes in a mouse model of ischemia-induced neuronal death and brain damage. Our central hypothesis is that astrocytes induce neuronal excitotoxic responses through enhanced Ca2+-dependent glutamate release (gliotransmission) and consequently contribute to ischemia-induced neuronal death and brain damage. A variety of state-of-the-art technologies including 2-P microscopy, electrophysiology, viral transduction and transgenic mice will be used to test this hypothesis. We have three SPECIFIC hypotheses: 1) Focal ischemia induces enhanced Ca2+ excitability in astrocytes in the ischemic core as well as in the penumbra and mediates glutamate release from these glial cells. Using 2-P in vivo Ca2+ imaging we will study the spatial and temporal dynamics of astrocytic Ca2+ signaling in the ischemic region and characterize the properties of Ca2+ oscillations. Using pharmacological interventions as well as astrocyte-specific molecular genetic approaches including viral transduction and transgenic mice, we will identify the molecular basis and the properties of astrocytic Ca2+ excitability that follows photothrombosis. 2) Astrocytes stimulate N-methyl-D-aspartate receptors (NMDARs)-mediated neuronal excitation during the period of their Ca2+ hyperexcitability following ischemia. Using 2-P microscopy and electrophysiology, we will determine the effects of gliotransmission on neuronal excitation following ischemia. Specifically, we will determine whether astrocytes stimulate the NR2B- containing NMDAR (NR2B-NMDAR)-mediated neuronal excitation after ischemia. 3) Astrocytes exacerbate ischemia-induced delayed neuronal death and brain damage through Ca2+-dependent gliotransmission. Using immunohistochemistry and a neuronal death assay, we will determine the role of gliotransmission in mediating neuronal death and brain damage. Furthermore we will test whether NR2B-NMDARs are involved in gliotransmission-mediated neuronal death. Although there are many studies suggesting the potential role of astrocytes in brain damage following ischemic injury, the lack of knowledge of biological properties of this type of glial cell together with the virtual absence of in vivo astrocyte-specific manipulations has hampered our progress in understanding their role in pathogenesis. By examining the novel hypothesis that alterations in Ca2+ signaling within and among astrocytes induce delayed neuronal death through gliotransmission, our study will provide entirely new insights into the physiological and pathological role of astrocytes in regulating neuronal excitability and excitotoxicity. Results from this project will advance the field of glial biology and provide therapeutic avenues and targets that could potentially ameliorate neuronal death and brain damage following ischemia. PUBLIC HEALTH RELEVANCE: Cerebral ischemia is a leading neurological disorder and has a major impact on public health. Understanding the cellular and molecular mechanism by which ischemia induces brain damage is essential for providing potential therapeutic avenues to minimize the damage. The proposed project will determine the novel role of a non-neuronal cell of the brain called astrocyte in regulating neuronal death and brain damage following ischemia. Results from this project will derive entirely new insights into the causes of ischemia-induced neurodegeneration.

描述（由申请人提供）：作为一种主要的神经系统疾病，急性脑缺血约占所有人类中风的 80%，对公共健康具有重大影响。了解病理生理学对于开发减少脑损伤的治疗途径至关重要。因此，该项目的目标是确定星形胶质细胞在缺血引起的神经元死亡和脑损伤的小鼠模型中的新作用。我们的中心假设是星形胶质细胞通过增强 Ca2+ 依赖性谷氨酸释放（胶质细胞传递）诱导神经元兴奋性毒性反应，从而导致缺血引起的神经元死亡和脑损伤。包括 2-P 显微镜、电生理学、病毒转导和转基因小鼠在内的各种最先进的技术将用于检验这一假设。我们有三个具体假设：1）局灶性缺血会诱导缺血核心和半暗带星形胶质细胞的 Ca2+ 兴奋性增强，并介导这些神经胶质细胞释放谷氨酸。使用 2-P 体内 Ca2+ 成像，我们将研究缺血区域星形细胞 Ca2+ 信号传导的空间和时间动态，并表征 Ca2+ 振荡的特性。利用药物干预以及星形胶质细胞特异性分子遗传学方法（包括病毒转导和转基因小鼠），我们将确定光血栓形成后星形胶质细胞 Ca2+ 兴奋性的分子基础和特性。 2) 星形胶质细胞在缺血后 Ca2+ 过度兴奋期间刺激 N-甲基-D-天冬氨酸受体 (NMDAR) 介导的神经元兴奋。使用 2-P 显微镜和电生理学，我们将确定胶质细胞传输对缺血后神经元兴奋的影响。具体来说，我们将确定缺血后星形胶质细胞是否刺激含有 NR2B 的 NMDAR (NR2B-NMDAR) 介导的神经元兴奋。 3）星形胶质细胞通过Ca2+依赖性胶质细胞传递加剧缺血引起的迟发性神经元死亡和脑损伤。使用免疫组织化学和神经元死亡测定，我们将确定胶质细胞传递在介导神经元死亡和脑损伤中的作用。此外，我们将测试 NR2B-NMDAR 是否参与胶质细胞传递介导的神经元死亡。尽管有许多研究表明星形胶质细胞在缺血性损伤后的脑损伤中具有潜在作用，但由于缺乏对此类神经胶质细胞生物学特性的了解，加上实际上缺乏体内星形胶质细胞特异性操作，阻碍了我们了解其作用的进展。在发病机制中的作用。通过检验星形胶质细胞内部和星形胶质细胞间 Ca2+ 信号传导的改变通过胶质细胞传递诱导延迟性神经元死亡的新假设，我们的研究将为星形胶质细胞在调节神经元兴奋性和兴奋性毒性中的生理和病理作用提供全新的见解。该项目的结果将推动神经胶质生物学领域的发展，并提供可能改善缺血后神经元死亡和脑损伤的治疗途径和目标。 公共健康相关性：脑缺血是一种主要的神经系统疾病，对公共健康具有重大影响。了解缺血引起脑损伤的细胞和分子机制对于提供潜在的治疗途径以尽量减少损伤至关重要。该项目将确定一种称为星形胶质细胞的大脑非神经元细胞在调节缺血后神经元死亡和脑损伤中的新作用。该项目的结果将对缺血引起的神经变性的原因产生全新的见解。