The Role of Gliotransmission in Cerebral Ischemia

胶质细胞传输在脑缺血中的作用

• 批准号: 8460525
• 负责人: Shinghua Ding
• 金额: $ 30.25万
• 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/8460525
• 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.

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％，对公共卫生有重大影响。了解病理生理学对于开发治疗途径以最大程度地减少脑损伤至关重要。因此，项目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的Ca2+依赖性谷氨酸释放（Gliotranssirs）诱导神经元兴奋性反应，从而导致缺血诱导的神经元死亡和脑损伤。各种最先进的技术，包括2-P显微镜，电生理学，病毒转导和转基因小鼠，用于检验该假设。我们有三个特定的假设：1）局灶性缺血可诱导缺血核心以及半体外星形胶质细胞中的Ca2+兴奋性增强，并介导这些神经胶质细胞中的谷氨酸释放。使用2-P IN VIVO Ca2+成像，我们将研究缺血区域中星形胶质细胞CA2+信号传导的空间和时间动力学，并表征Ca2+振荡的特性。使用药理学干预措施以及包括病毒转导和转基因小鼠在内的星形胶质细胞特异性分子遗传学方法，我们将确定遵循光膜瘤的分子基础和星形胶质细胞CA2+兴奋性的特性。 2）星形胶质细胞在缺血后Ca2+过度兴奋性期间刺激N-甲基-D-天冬氨酸受体（NMDARS）介导的神经元激发。使用2-P显微镜和电生理学，我们将确定胶质传递对缺血后神经元激发的影响。具体而言，我们将确定星形胶质细胞是否刺激含有NR2B的NMDAR（NR2B-NMDAR）介导的缺血后神经元激发。 3）星形胶质细胞通过Ca2+依赖性的Gliotrassermission加剧缺血诱导的延迟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法，我们将确定胶质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Gliotrission介导的神经元死亡。尽管有许多研究表明，缺血性损伤后星形胶质细胞在脑损伤中的潜在作用，但缺乏这种神经胶质细胞的生物学特性知识，以及实际上缺乏体内星形胶质细胞特异性操纵的缺乏，阻碍了我们在理解其在病原体中的作用方面的进步。通过研究新的假设，即星形胶质细胞内外的Ca2+信号传导的变化通过Gliotransersiser引起延迟的神经元死亡，我们的研究将提供对星形胶质细胞在调节神经元兴奋性和兴奋性毒性性中的生理和病理作用的全新见解。该项目的结果将推进神经胶质生物学领域，并提供治疗途径和靶标，这些途径可能会减轻缺血后的神经元死亡和脑损伤。