The Role of Neutrophils in Ischemia/Reperfusion Injury following Acute Stroke

中性粒细胞在急性中风后缺血/再灌注损伤中的作用

• 批准号: 10606952
• 负责人: Erika Arias
• 金额: $ 4.38万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-01 至 2026-09-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10606952
• 关键词: Acute; Address; Adhesions; Affect; Alteplase; American; Animal Model; Anti-Inflammatory Agents; Antibodies; Area; Beds; Binding; Blocking Antibodies; Blood Vessels; Blood flow; Brain; Brain Hypoxia; Brain Ischemia; Brain Pathology; Brain region; Cause of Death; Cell Adhesion Molecules; Cell surface; Cells; Central Nervous System; Cerebral Ischemia; Cerebrovascular system; Chronic; Clinical; Clinical Trials; Coagulation Process; Data; Development; Effectiveness; Endothelial Cells; Endothelium; Event; Excision; Extravasation; Fellowship; Hypoxia; Immune; Infarction; Infiltration; Inflammation; Inflammatory; Inflammatory Response; Injury; Ischemia; Ischemic Stroke; Laboratories; Leucocytic infiltrate; Leukocytes; Location; Manuscripts; Mediator; Methods; Minor; Modeling; Motor; Mus; Myeloid Cells; Necrosis; Outcome; PECAM1 gene; Paper; Pathologic; Pathology; Pathway interactions; Patients; Pattern; Physicians; Reperfusion Injury; Reperfusion Therapy; Research; Resolution; Rodent Model; Role; Scientist; Signal Transduction; Stroke; Techniques; Testing; Therapeutic; Therapeutic Effect; Therapeutic Intervention; Time; Tissues; Training; Visit; White Blood Cell Count procedure; Work; acute stroke; brain tissue; chemokine; clinically relevant; cytokine; disability; improved; improved outcome; in vivo; insight; intravital imaging; intravital microscopy; migration; mortality; nervous system disorder; neutrophil; novel therapeutic intervention; post stroke; preclinical study; prevent; protective effect; recruit; response; restoration; spatiotemporal; stroke model; stroke outcome; stroke therapy; targeted treatment; therapeutic target; thrombolysis

PROJECT SUMMARY/ABSTRACT Inflammation is the body's response to tissue damage, including brain tissue after stroke. Stroke is one of the leading causes of death and disability, affecting more that 795,000 Americans per year. A majority of strokes are ischemic strokes, where blood flow to the brain is obstructed. Most therapeutic interventions restore blood flow, but these therapies have a limited time frame in which they are effective. Moreover, some patients do not improve even with blood flow restoration. One likely explanation for the limited therapeutic benefit of blood flow restoration after stroke is the secondary damage caused by the acute inflammatory response. This is the so-called, “ischemia/reperfusion (I/R) injury.” Therefore, further understanding and characterization of the inflammatory response to stroke is critical to the development of new therapeutic interventions. Following an ischemic stroke, brain blood vessels respond to inflammatory signals and recruit leukocytes to the area of damage. Neutrophils (PMN) are the earliest responders to tissue damage in the central nervous system (CNS). Like other leukocytes, PMN interact with adhesion molecules on the endothelial cell surface and undergo transendothelial migration (TEM), squeezing between endothelial cells and migrating into the tissue bed. TEM is important because it is essentially irreversible, committing the cell to extravasation. Our research shows inhibition of TEM significantly reduces stroke infarct size in acute stroke, however the mechanism connecting TEM blockade to a reduction in infarct size is unknown. We show that blocking TEM alters the spatiotemporal distribution of leukocyte infiltration and extravasation across the ischemic core and penumbra but does not change the total number of leukocytes recruited to infarcted region. Analysis of the leukocyte composition showed PMN are the major infiltrating leukocyte type in acute stroke. These findings suggest that modulating PMN infiltration pattern rather than reducing total leukocyte recruitment may have a protective effect in stroke. We seek to understand the mechanisms by which myeloid cell TEM blockade results in reduced stroke infarct size and the effect of specifically interfering with PMN extravasation on stroke outcomes. To understand effect of TEM blockade following I/R, our first aim will identify how inhibition of TEM during I/R injury in acute stroke alters the immune landscape of the stroke microenvironment. Our studies will identify differences between in leukocyte types over time across ischemic brain regions and differences in the cytokine profile due to TEM blockade. Our second aim will determine the therapeutic effect of blocking leukocyte extravasation in comparison to selective PMN depletion following I/R. Our studies will be conducted at different time points after reperfusion, identifying the effect of inhibition on brain pathology, and mouse motor function. PMN extravasation will be inhibited through two methods: use of TEM-blocking antibodies and the selective depletion of PMN. Completion of these studies will provide insight into the mechanisms regulating PMN response to I/R injury and potentially identify a therapeutic intervention that can be used at the relevant time frame.

项目摘要/摘要 炎症是人体对组织损伤的反应，包括中风后脑组织。中风是一个 死亡和残疾的主要原因，每年影响更多79.5万美国人。大部分 中风是缺血性中风，流向大脑的血液被阻塞。大多数治疗干预措施还原 血流，但是这些疗法的有效时间有限。而且，有些患者 即使血流恢复也不改善。一个可能对血液治疗益处有限的解释 中风后的流量恢复是急性炎症反应引起的次要损害。这是 所谓的“缺血/再灌注（I/R）受伤。”因此，进一步理解和表征 对中风的炎症反应对于新的治疗干预措施的发展至关重要。 缺血性中风后，脑血管应对炎症信号并募集白细胞 到损坏区域。中性粒细胞（PMN）是最早对中枢神经组织损伤的反应者 系统（CNS）。像其他白细胞一样，PMN与内皮细胞表面上的粘合剂分子相互作用 经过跨内皮迁移（TEM），在内皮细胞之间挤压并迁移到组织床中。 TEM很重要，因为它本质上是不可逆的，可以将细胞渗出。 我们的研究表明，对TEM的抑制显着降低了急性中风的中风梗塞的大小，但是 连接TEM阻滞到梗塞大小的减小的机制尚不清楚。我们证明了阻止TEM 改变白细胞浸润和渗出跨缺血性核心的时空分布和 半月，但不会改变招募到梗塞区域的白细胞总数。分析 表现出的白细胞组成是急性中风中主要浸润的白细胞类型。这些发现 建议调节PMN浸润模式而不是减少总白细胞募集可能 中风的保护作用。我们寻求了解髓样细胞TEM封锁的机制 在减小的中风梗塞大小以及特异性干扰PMN渗出对中风结果的影响。 要了解I/R之后TEM封锁的效果，我们的第一个目标将确定对TEM的抑制 急性中风的I/R受伤改变了中风微环境的免疫景观。我们的研究将确定 白细胞类型的差异随着缺血性脑区域的差异和细胞因子的差异 由于TEM封锁而引起的轮廓。我们的第二个目标将确定阻断白细胞的治疗作用 与I/R之后的选择性PMN耗竭相比，渗出。我们的研究将在不同的 再灌注后的时间点，确定抑制对脑病理学和小鼠运动功能的影响。 PMN的渗出将通过两种方法抑制：使用tembocking抗体和选择性 PMN的耗竭。这些研究的完成将提供有关调节PMN反应的机制 为I/R损伤，并有可能确定可以在相关时间范围内使用的治疗干预措施。