HMG1 SIGNALING IN INFLAMMATION FOLLOWING BRAIN ISCHEMIA

HMG1 信号在脑缺血后炎症中的作用

• 批准号: 7361374
• 负责人: Michael A. Moskowitz
• 金额: $ 22.97万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7361374
• 关键词: Address; Advanced Glycosylation End Products; Animal Model; Area; Astrocytes; Binding; Biochemical; Biological Assay; Blocking Antibodies; Boxing; Brain; Brain Injuries; Brain Ischemia; Cell Adhesion Molecules; Cell Death; Cell Nucleus; Cells; Central Nervous System Diseases; Complex; Culture Media; Cultured Cells; Cytokine Activation; Cytoplasm; Cytosol; DNA-Binding Proteins; Data; Development; Endothelial Cells; Endothelium; Evolution; Extracellular Space; Fc Receptor; Gene Expression; Glucose; HMGB1 Protein; Immune system; In Vitro; Inflammation; Inflammatory; Inflammatory Response; Injury; Ischemic Brain Injury; Ischemic Stroke; Knockout Mice; Knowledge; Lesion; Leukocytes; Link; MAP Kinase Gene; Mediator of activation protein; Membrane; Microglia; Mitogen-Activated Protein Kinases; Molecular; Mus; N-Methylaspartate; Necrosis; Neurons; Nuclear; Nuclear Protein; Nuclear Proteins; Numbers; Oxygen; Pathway interactions; Play; Protein Overexpression; Recombinant Proteins; Recombinants; Recruitment Activity; Reporting; Role; Sepsis; Signal Pathway; Signal Transduction; Signaling Molecule; Stream; Stroke; System; TLR4 gene; Testing; Time; Toll-Like Receptor 2; Transcriptional Activation; Up-Regulation; base; brain cell; cell type; cytokine; deprivation; in vivo; injured; ischemic lesion; macrophage; mouse model; neuroinflammation; neuroprotection; neurovascular unit; novel; novel therapeutics; receptor; size; toll-like receptor 4

DESCRIPTION (provided by applicant): In ischemic stroke, multiple types of brain cells in the neurovascular unit engage in a complex array of signaling mechanisms evolving during brain injury and leading to inflammation and cell death. The nuclear protein HMG-1 is a master regulator of inflammation. Once released from cells, HMG-1 upregulates a host of inflammatory cytokines and activates a number of different inflammatory cells. The known downstream receptor targets for HMG-1 are RAGE, TLR2 and TLR4. Very little is known, however, about whether this upstream signaling molecule HMG-1 plays a role in neuroinflammation, in particular following ischemic stroke. Preliminary data, obtained in a mouse model of transient brain ischemia, suggest that HMG-1 is both translocated from the nucleus and released from the cytosol rapidly after ischemic brain injury. We therefore hypothesize that HMG-1, once released from brain cells after ischemic stroke, triggers an inflammatory response by upregulating inflammatory mediators and recruiting leukocytes to the ischemic territory. We will explore the novel hypothesis that the inflammatory response elicited by HMG-1 contributes to a cascade of injury pathways within the neurovascular unit exacerbating ischemic damage. Blockade of HMG-1 signaling may therefore be a new and effective approach to reducing ischemic injury. We propose 3 aims to explore this hypothesis. Aim 1 will confirm and extend preliminary data establishing that brain ischemia causes HMG-1 translocation from the nucleus to the cytoplasm and then its release into the extracellular space. Aim 2 will characterize the signaling pathways of HMG-1 in brain cells, in vitro, based on results from other systems. This will include assessing the expression of HMG-1 putative receptors (RAGE, TLR2 and TLR4), as well as the up-regulation of cytokines (TNF-a, IL-1¿) and other inflammatory-associated molecules associated with stimulation of MAPK and NF?B upon treatment with recombinant HMG-1 and blockade by monoclonal anti-HMG-1, particularly within the endothelium. Aim 3 will test the hypothesis that inhibition of HMG-1 signaling modulates the inflammatory response and possibly reduces brain lesion size after MCAo in mouse. We therefore propose to explore biochemical and molecular approaches to demonstrate a pivotal role for HMG-1 in ischemic brain injury and by so doing, investigate novel signaling cascades and treatment targets for stroke. The inflammatory response to brain ischemia has been causally linked to brain damage. The nuclear protein HMG-1 has been shown to be a master regulator of inflammation in some situations like systemic sepsis, but it is not known whether it plays any role in inflammation following brain ischemia. This application proposes to explore biochemical and molecular approaches to demonstrate a pivotal role for HMG-1 in ischemic brain injury and by so doing, investigate novel signaling cascades and treatment targets for stroke.

描述（由申请人提供）：在缺血性卒中中，神经血管单元中的多种类型的脑细胞参与脑损伤期间演变的一系列复杂的信号传导机制，并导致炎症和细胞死亡。核蛋白HMG-1是炎症的主要调节剂。一旦从细胞中释放出来，HMG-1就会上调许多炎症细胞因子并激活许多不同的炎症细胞。已知的HMG-1的下游受体靶标是TLR、TLR 2和TLR 4。然而，关于这种上游信号分子HMG-1是否在神经炎症中发挥作用，特别是在缺血性中风后，我们知之甚少。在小鼠短暂性脑缺血模型中获得的初步数据表明，HMG-1在缺血性脑损伤后迅速从细胞核移位并从细胞质中释放。因此，我们假设HMG-1一旦在缺血性中风后从脑细胞释放，通过上调炎症介质和将白细胞募集到缺血区域来触发炎症反应。我们将探讨新的假说，即HMG-1引起的炎症反应有助于神经血管单位内的损伤途径级联，加剧缺血性损伤。因此，阻断HMG-1信号通路可能是减轻缺血性损伤的一种新的有效方法。我们提出了3个目的来探讨这一假设。目的1将证实和扩展初步数据，建立脑缺血导致HMG-1从细胞核易位到细胞质，然后释放到细胞外空间。目的2将根据其他系统的结果，在体外表征HMG-1在脑细胞中的信号通路。这将包括评估HMG-1假定受体（TNF，TLR 2和TLR 4）的表达，以及细胞因子（TNF-α，IL-1？）和其他与MAPK和NF刺激相关的炎症相关分子的上调。B，用重组HMG-1治疗并用单克隆抗HMG-1阻断后，特别是在内皮内。目的3将检验抑制HMG-1信号传导调节小鼠MCAo后的炎症反应并可能减小脑损伤大小的假设。因此，我们建议探索生物化学和分子方法来证明HMG-1在缺血性脑损伤中的关键作用，并通过这样做，研究新型信号级联反应和中风的治疗靶点。对脑缺血的炎症反应与脑损伤有因果关系。核蛋白HMG-1已被证明是在某些情况下，如全身性脓毒症的炎症的主要调节因子，但它是否在脑缺血后的炎症中发挥任何作用尚不清楚。本申请提出探索生物化学和分子方法来证明HMG-1在缺血性脑损伤中的关键作用，并通过这样做，研究新的信号级联和中风的治疗靶点。