Involvement of astrocytic two-pore domain K+ channels in ischemic pathology

星形细胞双孔域 K 通道参与缺血病理学

• 批准号: 8470252
• 负责人: MIN ZHOU
• 金额: $ 31.55万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8470252
• 关键词: Accounting; Acidosis; Affect; Antibodies; Apoptotic; Area; Astrocytes; Brain; Carotid Arteries; Cause of Death; Cell Death; Cell Proliferation; Cerebral Ischemia; Cerebrovascular Circulation; Chemosensitization; Electrophysiology (science); Event; Failure; Future; GLAST Protein; Genes; Glial Fibrillary Acidic Protein; Glucose; Gramicidin; Hippocampus (Brain); Hour; Hypoglycemia; Hypoxia; Immunohistochemistry; Individual; Infarction; Ischemia; Lead; Lesion; Light; Mediating; Membrane Potentials; Metabolic; Modeling; Monitor; Necrosis; Neuraxis; Neuronal Injury; Neurons; Neuroprotective Agents; Neurotransmitters; Outcome; Oxygen; Pathology; Peripheral; Pharmaceutical Preparations; Physiological; Potassium Channel; Predisposition; Proliferation Marker; Rattus; Riluzole; Role; Signal Transduction; Simulate; Slice; Staining method; Stains; Stimulus; Stroke; Testing; Therapeutic; Uncertainty; United States; Withdrawal; artery occlusion; base; brain cell; cell type; deprivation; disability; immunocytochemistry; insight; knock-down; member; neuronal survival; neurotransmitter release; novel; post stroke; potassium channel protein TREK-1; public health relevance; resilience; response; therapeutic target; voltage

DESCRIPTION (provided by applicant): Astrocytes are the most numerous cell types in the brain and are known to provide structural, metabolic and homeostatic support to the central nervous system (CNS). Although astrocytes can better survive than neurons in cerebral ischemia, the mechanisms accounting for such a different susceptibility among different brain cells are not clear. Predominant expression of a voltage-independent K+ channel conductance, or passive conductance, is a hallmark of mature astrocytes and essential for the homeostatic support of astrocytes to the CNS. Now we know that two members of the two-pore domain K+ channels (K2Ps) K+ channels, TWIK-1 and TREK-1, are among the long-sought for K+ channels accounting for astrocyte passive conductance. K2Ps can be dynamically modulated by a variety of physiochemical and pathological stimuli, including cerebral-ischemia-produced-neuronal-injury-factors (CIPNJFs), such as hypoxia, hypoglycemia, acidosis and pathological release of neurotransmitters. Pathological induction of K2P expression also contributes to the necrotic and apoptotic cell death and cell proliferation that are the two prominent pathological events occurring in the ischemic infarct and penumbra regions. To understand how the physiological expression of astrocyte K2Ps offers protection to astrocytes against early ischemic insults, and how the long-term ischemic conditions induce altered K2P expression in reactive astrocytes and its consequence on the post-stroke outcomes, we hypothesize that the activity of astrocytic K2Ps can be modulated by CIPNJFs in a manner protecting astrocytes against early ischemic insults, and the altered expression of K2P in reactive astrocytes contributes to the compromised homeostatic function in the peri- infarct penumbra region. Five specific aims are proposed to explore these completely unknown areas. 1) Modulation of astrocyte membrane potential and passive conductance by CIPNJFs. This will be done in rat hippocampal slices with gramicidin perforated patch recording to monitor K2Ps modulation without interfering with the CIPNJFs mediated intracellular energy failure and altered signal transduction; 2) Modulation of electrophysiological response of astrocytes to CIPNJFs by neuroprotectant and TREK-1 channel modulator riluzole and sipatrigine; 3) Identify specific K2P-CIPNJF interaction mechanisms by selective silencing of astrocytic K2Ps with siRNAs in organotypic hippocampal slice cultures; 4) Identify K2P expression in rat hippocampal reactive astrocytes in slices prepared from the penumbra region after reversible middle carotid artery occlusion (rMCAO) by confocal immunocytochemistry. 5) Identify functional K2P in reactive astrocytes in rat focal ischemia penumbra region using electrophysiology in acutely prepared hippocampal slices from the rat rMCAO penumbra region. The proposed studies should provide novel insights into the physiological roles and pathological involvement of astrocytic K2P in cerebral ischemia and whether these predominant astrocytic K+ channels could be potential targets for stroke therapeutic strategy.

描述（由申请人提供）：星形胶质细胞是大脑中最多的细胞类型，已知为中枢神经系统（CNS）提供结构，代谢和稳态支持。尽管在脑缺血中，星形胶质细胞比神经元更好地生存，但是造成不同脑细胞之间这种敏感性这种敏感性这种不同的机制尚不清楚。不依赖电压的K+通道电导或被动电导的主要表达是成熟星形胶质细胞的标志，对于星形胶质细胞对CNS的体内平衡支持至关重要。现在，我们知道，两孔域K+通道（K2P）K+通道的两个成员TWIK-1和TREK-1是长期以来对星形胶质细胞被动电导的K+通道的持久。 K2P可以通过多种生理化学和病理刺激进行动态调节，包括脑部化学性质生产的神经元侵害因子（CIPNJFS），例如缺氧，低血糖，低血糖，酸中毒，酸中毒和病理学释放。 K2P表达的病理诱导也有助于坏死和凋亡细胞死亡和细胞增殖，这是缺血性梗死和阴茎区域中发生的两个突出的病理事件。要了解星形胶质细胞K2P的生理表达如何为星形胶质细胞提供防止早期缺血性损伤的保护，以及长期的缺血状况如何诱导反应性星形胶质细胞中K2P表达的改变及其对冲程后结果的影响，我们对早期的cipnjfemits a Attracts to cipnjfemits a Attrots a cipnjfement s tosection coptime cipnjfempts and Stroke cipnjfement and Stonjfemy ins cipnjfem and strote cipnjfem的影响。反应性星形胶质细胞中K2P的表达改变导致梗塞周围阴茎区域的稳态功能受损。提出了五个具体目标来探索这些完全未知的领域。 1）CIPNJFS对星形胶质膜电位和被动电导的调节。这将在大鼠海马切片中进行谷霉素塑料贴片记录，以监测K2PS调制，而不会干扰CIPNJFS介导的细胞内能量故障并改变了信号转导。 2）通过神经保护剂和Trek-1通道调节剂Riluzole和Sipatrigine对星形胶质细胞对CIPNJF的电生理反应调节； 3）通过在器官海马切片培养物中选择性沉默与星形胶质细胞K2P的选择性沉默来确定特定的K2P-CIPNJF相互作用机制； 4）通过共共共聚焦免疫细胞化学，在可逆的颈中部动脉闭塞（RMCAO）后，在大鼠海马反应性星形胶质细胞中鉴定在大鼠海马反应性星形胶质细胞中的表达。 5）在大鼠rmcao penumbra区域的急性准备的海马切片中，使用电生理学鉴定大鼠局灶性缺血区域反应性星形胶质细胞中的功能性K2P。拟议的研究应提供有关星形胶质细胞K2P在脑缺血中的生理作用和病理参与的新见解，以及这些主要的星形胶质细胞K+通道是否可能是中风治疗策略的潜在目标。