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.

项目总结/摘要 炎症是身体对组织损伤的反应，包括中风后的脑组织。中风是一种 死亡和残疾的主要原因，每年影响超过795，000美国人。大多数 中风是缺血性中风，其中流向大脑的血液被阻塞。大多数治疗性干预可以恢复 血液流动，但这些疗法有一个有限的时间框架，他们是有效的。此外，一些患者 即使血流恢复也不会改善。血液治疗效果有限的一个可能解释是 中风后的血流恢复是由急性炎症反应引起的继发性损害。这是 即所谓的“缺血/再灌注（I/R）损伤”。因此，进一步理解和表征 对中风的炎症反应对于开发新的治疗干预是至关重要的。 缺血性中风后，脑血管对炎症信号作出反应并募集白细胞 到损坏的区域。中性粒细胞（PMN）是中枢神经系统组织损伤的最早反应者， 系统（CNS）。与其他白细胞一样，PMN与内皮细胞表面的粘附分子相互作用， 经历跨内皮迁移（TEM），在内皮细胞之间挤压并迁移到组织床中。 TEM是重要的，因为它基本上是不可逆的，使细胞外渗。 我们的研究表明，抑制TEM可以显著减少急性卒中的梗死面积， TEM阻断与梗死面积减小的联系机制尚不清楚。我们表明，阻塞TEM 改变了缺血中心白细胞浸润和外渗的时空分布， 半暗带，但不改变募集到梗死区域的白细胞总数。分析 白细胞组成显示中性粒细胞是急性脑卒中主要的浸润性白细胞类型。这些发现 提示调节PMN浸润模式而不是减少总白细胞募集可能具有 中风的保护作用。我们试图了解髓系细胞TEM阻断导致 减少卒中梗死面积和特异性干预PMN外渗对卒中结局的影响。 为了了解I/R后TEM阻断的效果，我们的第一个目标将确定在I/R期间TEM的抑制如何。 急性卒中中的I/R损伤改变了卒中微环境的免疫景观。我们的研究将确定 缺血性脑区白细胞类型随时间的差异和细胞因子的差异 由于TEM阻塞而导致的轮廓。我们的第二个目标是确定阻断白细胞的治疗效果。 与I/R后选择性PMN耗竭相比，我们的研究将在不同的 再灌注后的时间点，鉴定抑制对脑病理学和小鼠运动功能的影响。 PMN外渗将通过两种方法抑制：使用TEM阻断抗体和选择性免疫抑制剂。 中性粒细胞减少。这些研究的完成将为了解PMN反应的调节机制提供线索 I/R损伤，并可能确定可在相关时间范围内使用的治疗干预。