Pathological role of the SUR1-regulated NC(Ca-ATP) channel in cortex after subara

Subara后皮质中SUR1调节的NC(Ca-ATP)通道的病理作用

• 批准号: 7767667
• 负责人: J. Marc Simard
• 金额: $ 32.16万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-15 至 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7767667
• 关键词: Blood; Blood - brain barrier anatomy; Blood capillaries; Brain Hypoxia-Ischemia; Capillary Endothelial Cell; Cell Death; Cells; Cerebral Edema; Cerebrovascular Spasm; Cessation of life; Co-Immunoprecipitations; Coupled; Edema; Functional disorder; Genes; Glyburide; Grant; Hemorrhage; Impaired cognition; Inflammation; Inflammatory; Ion Channel; Lead; Link; Measures; Messenger RNA; Modeling; Molecular; Nature; Neurons; Outcome; Outcome Study; Pathway interactions; Patients; Play; Production; Proteins; Rattus; Rodent Model; Role; Series; Stimulus; Subarachnoid Hemorrhage; Swelling; Time; Tissues; Up-Regulation; Vasospasm; Work; base; capillary; caspase-3; central nervous system injury; cytokine; cytotoxic; functional outcomes; improved; in vivo; inhibitor/antagonist; insight; knock-down; neurobehavioral; neuroinflammation; neuron loss; novel; novel therapeutic intervention; outcome forecast; patch clamp; prevent; public health relevance; research study; sulfonylurea receptor; vasoconstriction; venule

DESCRIPTION (provided by applicant): During the last 5 decades, cerebral vasospasm has been thought to be the principal cause of poor outcome following subarachnoid hemorrhage (SAH). Recently, this idea has been challenged by the observation that successful reversal of vasoconstriction often does not result in concomitant improvement in patient outcome. Without denying the enduring significance of vasospasm, there is an emerging concept that factors other than vasoconstriction are important in the pathophysiology and prognosis post-SAH, including disruption of the blood-brain barrier, and activation of inflammatory and cell death pathways. Inflammation due to the toxic nature of blood is likely to be a very significant cause of edema formation and neuronal loss post-SAH, resulting in short-term and long-term cortical dysfunction and delayed cognitive impairment. We recently discovered a new ion channel, the sulfonylurea receptor-1 (SUR1)-regulated NC(Ca- ATP) channel, whose activation is associated with formation of cerebral edema and neuronal cell death. Our previous work demonstrated that this channel is upregulated in the context of ischemia/hypoxia. Recently, we discovered that this channel is also prominently upregulated in the context of neuroinflammation. Using a rat model of moderate SAH, in which delayed vasospasm is negligible but neuroinflammation is reliably produced, we found that: (i) the regulatory and the pore-forming subunits of the NC(Ca-ATP) channel, SUR1 and TRPM4, are prominently up-regulated in neurons, capillaries and venules in cortical regions with overlying SAH; (ii) cortical regions that show up-regulation of SUR1 and TRPM4 also show strong TNF1 upregulation, vasogenic edema and caspase-3 activation; (iii) post-SAH treatment with glibenclamide or with anti-sense oligodeoxynucleotide directed against SUR1 significantly reduces TNF1 upregulation, vasogenic edema and caspase-3 activation. In this grant, we plan 3 specific aims (SA) to: (SA1) demonstrate that glibenclamide ameliorates post-SAH inflammation and edema, that it preserves neuronal integrity and improves neurobehavioral outcome in a rat model of SAH; (SA2) demonstrate that the beneficial effects of glibenclamide are replicated by gene suppression of either of the two subunits of the channel, SUR1 and TRPM4; (SA3) demonstrate that up-regulation of SUR1 and TRPM4 protein and mRNA post-SAH is associated with functional NC(Ca-ATP) channels. We anticipate that successful completion of the proposed experiments will yield novel molecular insights into SAH-induced cortical dysfunction, and will lead to new therapeutic approaches to prevent the devastating cognitive impairments that so often afflict SAH patients. PUBLIC HEALTH RELEVANCE: Subarachnoid hemorrhage (SAH) results in edema, neuronal loss and cognitive dysfunction attributable in part to post-SAH hemotoxicity-induced inflammation independent of vasospasm. Using a rodent model of SAH, we discovered that SUR1 and TRPM4, the molecular subunits of the NC(Ca-ATP) channel, are prominently up-regulated post-SAH. In this proposal, we will use a rat model of SAH to establish the essential role of the NC(Ca-ATP) channel in pathophysiology post-SAH.

描述（由申请人提供）：在过去的50年中，脑血管痉挛被认为是蛛网膜下腔出血（SAH）后预后不良的主要原因。最近，这一想法受到了挑战，因为观察到血管收缩的成功逆转通常不会导致患者结局的伴随改善。在不否认血管痉挛的持久意义的情况下，有一个新兴的概念，即血管收缩以外的因素在SAH后的病理生理学和预后中是重要的，包括血脑屏障的破坏，以及炎症和细胞死亡途径的激活。由于血液的毒性性质引起的炎症可能是SAH后水肿形成和神经元损失的非常重要的原因，导致短期和长期皮质功能障碍和迟发性认知障碍。我们最近发现了一种新的离子通道，磺酰脲受体-1（SUR 1）调节的NC（Ca-ATP）通道，其激活与脑水肿和神经细胞死亡的形成有关。我们以前的工作表明，该通道在缺血/缺氧的情况下上调。最近，我们发现这个通道在神经炎症的背景下也显著上调。利用大鼠中度蛛网膜下腔出血模型（迟发性血管痉挛可忽略，但神经炎症确实产生），我们发现：（i）NC（Ca-ATP）通道的调节亚基和成孔亚基SUR 1和TRPM 4在蛛网膜下腔出血皮层区域的神经元、毛细血管和微静脉中显著上调;（ii）显示SUR 1和TRPM 4上调的皮质区域也显示强烈的TNF 1上调、血管源性水肿和半胱天冬酶-3活化;（iii）SAH后用格列本脲或用针对SUR 1的反义寡脱氧核苷酸治疗显著降低TNF 1上调，血管源性水肿和caspase-3激活。在这项资助中，我们计划了3个具体目标（SA）：（SA 1）证明格列本脲改善SAH后炎症和水肿，在SAH大鼠模型中保持神经元完整性并改善神经行为结果;（SA 2）证明格列本脲的有益作用通过对通道的两个亚基（SUR 1和TRPM 4）中任一个的基因抑制而复制;（SA 3）证实SAH后SUR 1和TRPM 4蛋白和mRNA的上调与功能性NC（Ca-ATP）通道相关。我们预计，成功完成拟议的实验将产生新的分子见解SAH诱导的皮质功能障碍，并将导致新的治疗方法，以防止破坏性的认知障碍，所以经常困扰SAH患者。公共卫生相关性：蛛网膜下腔出血（SAH）导致水肿、神经元丢失和认知功能障碍，部分原因是SAH后血液毒性诱导的炎症，与血管痉挛无关。使用SAH的啮齿动物模型，我们发现，SUR 1和TRPM 4，NC（Ca-ATP）通道的分子亚基，在SAH后显著上调。在这个建议中，我们将使用大鼠模型SAH建立的NC（Ca-ATP）通道在SAH后的病理生理学的重要作用。