Inflammatory Mechanisms of Brain - Lymphatic Signaling in Stroke

脑部炎症机制 - 中风时的淋巴信号传导

基本信息

批准号：
9334323
负责人：
Kazuhide Hayakawa
金额：
$ 37.22万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-09-01 至 2021-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9334323
关键词：
Astrocytes Back Biological Assay Biological Markers Biology Blood Vessels Brain Brain Edema Brain Injuries CCL23 gene CD 200 Cell Culture Techniques Cell Survival Cells Cerebral Ischemia Cerebrospinal Fluid Cervical lymph node group Data Dextrans Drainage procedure Electron Microscopy Endothelial Cells Endothelium Etiology Evans blue stain Glucose Image Immune Immune response Immune system In Vitro Inflammation Inflammatory Inflammatory Response Infusion procedures Injectable Interferons Interruption Ischemia Knowledge Lymphangiogenesis Lymphatic Lymphatic Endothelial Cells Lymphatic Endothelium Lymphatic System Macrophage Activation Migration Assay Molecular Mus Myelin Neurological outcome Operative Surgical Procedures Oryctolagus cuniculus Outcome Oxygen Pathway interactions Pericytes Peripheral Permeability Pharmacology Phenotype Publishing Rattus Recruitment Activity Reporter Signal Transduction Small Interfering RNA Staining method Stains Stroke System TLR4 gene Techniques Testing Therapeutic Tracer Transgenic Organisms Travel Tube Vascular Endothelial Growth Factor C Water Western Blotting X-Ray Computed Tomography base brain endothelial cell brain parenchyma chemokine cytokine deprivation experimental study gray matter improved in vivo in vivo Model inhibitor/antagonist injured kinase inhibitor loss of function lymph nodes lymphatic drainage lymphatic pump macrophage matrigel migration monocyte mouse model neuroinflammation neurovascular injury neurovascular unit neutralizing antibody notch protein novel post stroke potential biomarker prevent response screening spatiotemporal stroke therapy targeted biomarker tool white matter white matter damage

项目摘要

Inflammatory Mechanisms of Brain-Lymphatic Signaling in Stroke After stroke, the peripheral immune system becomes activated, and these systemic inflammatory responses are known to amplify brain injury and worsen outcomes. But a major gap in knowledge remains. It is unclear how the stroke-damaged brain sends signals to the periphery. Recently, it has been suggested that some type of specialized lymphatic drainage system may exist in the CNS. Back in 1995, we had used CT imaging to show that tracers injected into rabbit brain can directly drain into the cervical lymph nodes in vivo (Hunter et al, Neuropath Appl Neurobiol 1995). We now propose that this brain-to-cervical-lymph node connection may provide a potential pathway for inflammatory crosstalk between brain and systemic responses after stroke. Based on our pilot data, we propose the hypothesis that after stroke, the injured neurovascular unit releases signals that drain into the cervical lymph node and activate macrophages thus worsening neuroinflammation and stroke outcomes: (i) after focal ischemia, brain astrocytes/pericytes/endothelial cells secrete VEGF-C into CSF; (ii) VEGF-C travels into cervical lymph nodes, enhances pro-inflammatory signals in lymphatic endothelium, and induces M1-like macrophage polarization and recruitment; (iii) M1-like macrophages then contribute to further neuroinflammation and brain injury in both gray and white matter. We will test this hypothesis in three integrated aims, using a combination of molecular tools, cell culture, and in vivo models. In Aim 1, we assess and compare mechanisms for how astrocytes, pericytes and brain endothelial cells release VEGF-C after oxygen-glucose deprivation. In Aim 2, we investigate mechanisms that underlie the ability of VEGF-C to induce inflammation in lymphatic endothelium and activate macrophages. In Aim 3, we will use mouse models of focal cerebral ischemia to confirm these brain-to-lymphatic signals in vivo, and examine therapeutic approaches that may interrupt this pathway to improve stroke outcomes. To assess causality in our pathways, we will conduct gain and loss-of-function experiments using a combination of cell culture, in vivo mouse models, pharmacologic inhibitors, molecular techniques including siRNA and transgenics, long-term neurological outcomes, and imaging. This project should define a novel mechanism wherein the damaged neurovascular unit communicates with peripheral lymphatics after stroke. Our findings may provide a new conceptual framework for seeking potential stroke targets and biomarkers in the lymphatic system. Finally, this project may also help open up new collaborative crosstalk between stroke biology and the well established field of lymphatic vascular biology.

中风中脑淋巴信号传导的炎症机制中风后，外周免疫系统被激活，这些全身炎症反应已知会加剧脑损伤并使结果恶化。但知识方面仍然存在重大差距。目前还不清楚中风受损的大脑如何向周围发送信号。最近，有人提出，某些类型的专门淋巴引流系统可能存在于中枢神经系统。早在1995年，我们就用CT成像证明，注射到兔脑中的示踪剂可以直接引流进入体内颈部淋巴结（Hunter 等人，Neuropath Appl Neurobiol 1995）。我们现在建议这个脑与颈部淋巴结的连接可能为炎症串扰提供了潜在的途径中风后的大脑和全身反应。根据我们的试验数据，我们提出这样的假设：中风后，受伤的神经血管单元会释放信号流入颈部淋巴结并激活巨噬细胞，从而加剧神经炎症和中风结果：(i) 局灶性缺血后，脑星形胶质细胞/周细胞/内皮细胞将 VEGF-C 分泌到脑脊液； (ii) VEGF-C 进入颈部淋巴结，增强淋巴管中的促炎信号内皮细胞，并诱导 M1 样巨噬细胞极化和招募； (iii) M1 样巨噬细胞导致灰质和白质的进一步神经炎症和脑损伤。我们将测试这个结合分子工具、细胞培养和体内模型，提出三个综合目标的假设。在目标 1 中，我们评估并比较星形胶质细胞、周细胞和脑内皮细胞如何发挥作用的机制氧糖剥夺后释放 VEGF-C。在目标 2 中，我们研究了潜在的机制 VEGF-C 诱导淋巴内皮炎症并激活巨噬细胞的能力。在目标 3 中，我们将使用局灶性脑缺血小鼠模型在体内确认这些脑至淋巴信号，并检查可能会中断该途径以改善中风结果的治疗方法。评估我们的因果关系途径，我们将结合细胞培养、体内小鼠模型、药理学抑制剂、包括 siRNA 和转基因在内的分子技术、长期神经学结果和影像学。该项目应该定义一种新的机制，其中受损的神经血管单元与中风后的外周淋巴管。我们的研究结果可能为寻找潜力提供一个新的概念框架淋巴系统中的中风目标和生物标志物。最后，该项目还可能有助于开辟新的中风生物学和成熟的淋巴血管生物学领域之间的协作串扰。