The role of CD11c+ microglia in post-ischemic stroke recovery

CD11c小胶质细胞在缺血性中风后恢复中的作用

基本信息

批准号：
10542785
负责人：
EDWIN CHI KEUNG WAN
金额：
$ 19万
依托单位：
WEST VIRGINIA UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-01-01 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10542785
关键词：
Ablation Alteplase Animal Model Anti-Inflammatory Agents Apoptotic Area Binding Blood Bone Marrow Brain Brain Infarction Brain Injuries Cell Adhesion Cell physiology Cell secretion Cells Chimera organism Chronic Phase Cicatrix Complement 3b Data Dendritic Cells Dimerization Disease Excision Genes Goals Heterogeneity Hour ITGAX gene ITGB2 gene Infarction Inflammation Inflammation Mediators Inflammatory Inflammatory Response Integrin alpha Chains Integrin alphaXbeta2 Intercellular adhesion molecule 1 Interleukin-10 Ischemia Ischemic Stroke Mechanics Mediating Microglia Middle Cerebral Artery Occlusion Mouse Protein Mouse Strains Mus Myelin Myeloid Cells Names Neurologic Neurologic Deficit Patients Phagocytes Phagocytosis Phenotype Play Proteins Recovery Reperfusion Therapy Reporter Reporting Resolution Role Signal Transduction Stroke Testing Thrombectomy Time Tissues Vascular Cell Adhesion Molecule-1 brain size cell motility cognitive disability experience improved ischemic injury migration monocyte neurological recovery neuron loss neuron regeneration neuroprotection neurotoxic novel strategies novel therapeutic intervention physically handicapped post stroke promoter protective effect red fluorescent protein repaired response single-cell RNA sequencing stroke recovery stroke survivor tissue repair transcriptome

项目摘要

Project Summary/Abstract Current treatment options for patients experienced ischemic stroke allow blood reperfusion to the brain but fails to resolve the neurological deficits, which cause long-term physical and cognitive disabilities in stroke survivors. Thus, novel therapeutic strategies for improving brain recovery and resolving neurological deficits are critically needed. Neuronal death induces the activation of microglia that express proinflammatory mediators, leading to the exacerbation of brain damage following ischemic stroke. Thus, targeting microglia was thought to ameliorate brain injury post-stroke. However, recent studies have shown that the elimination of microglia increases the size of brain infarct and worsens the neurological deficits of mice following transient middle cerebral artery occlusion (tMCAO), an animal model for ischemic stroke studies. These data suggest a functional heterogeneity of microglia in response to ischemic insults, or a temporal phenotypic shift of microglia from neurotoxic to neuroprotective over time following ischemic injury. The goal of this proposal is to investigate whether the CD11c- mediated signaling potentiates these diverse functions or phenotypical shift in microglia, and to determine the potential neuroprotective role of CD11c+ microglia in brain recovery following ischemic stroke. CD11c is an integrin alpha chain protein that is widely used as a defining marker for conventional dendritic cells (cDCs). CD11c regulates cell adhesion, migration, and phagocytic activity of cDCs. The role of CD11c-mediated signaling in microglia following ischemic stroke is not known. Transcriptome analysis suggests that CD11c+ microglia may play a protective role following neurological insults, but experimental evidence to support this notion is lacking. We performed tMCAO in Ccr2+/RFP x CD11c-EYFP mice, and observed a substantial increase of CD11c+ microglia in the brain following tMCAO. Our preliminary data have shown that 1) CD11c+ microglia mainly appeared at the border of infract of the brain 72 hours following tMCAO. These microglia predominately co- expressed the activation marker IBA-1; 2) CD11c+ IBA-1+ microglia migrated to and were maintained within the glial scar 14 days following tMCAO; and 3) On day 14, a subset of CD11c+ IBA-1- microglia appears at the peri- infarct area of the brain. In Aim 1, we hypothesize that CD11c expression in microglia promotes brain recovery by directing the migration of microglia to the infarct core, and enhances their ability to eliminate dead cells. We will address this hypothesis using CD11c-EYFP reporter mice crossed with CD11c-deficient mice. The role of CD11c in microglia in promoting brain recovery following ischemic stroke will be further determined by single- cell RNA sequencing. In Aim 2, we hypothesize that the elimination of CD11c+ microglia at the chronic phase following ischemic injury increases brain infarct and exacerbates neurological deficits. We will test this hypothesis using a bone marrow chimera strategy, in which tMCAO will be performed in mice that CD11c+ microglia are selectively ablated. Elucidating the mechanisms by which microglia switch from proinflammatory to neuroprotective can help develop novel strategies that promote neurological recovery following ischemic stroke.

项目摘要/摘要患者的当前治疗选择经验丰富的缺血性中风允许血液再灌注大脑，但失败解决神经系统缺陷，这会导致中风幸存者的长期身体和认知障碍。因此，改善大脑恢复和解决神经功能缺陷的新型治疗策略至关重要需要。神经元死亡诱导表达促炎介质的小胶质细胞的激活，导致缺血性中风后脑损伤加剧。因此，靶向小胶质细胞被认为可以改善中风后脑损伤。但是，最近的研究表明，消除小胶质细胞会增加大小脑梗塞并恶化小鼠的神经缺陷后瞬时脑动脉阻塞（TMCAO），一种缺血性中风研究的动物模型。这些数据表明功能异质性的小胶质细胞响应缺血性侮辱或小胶质细胞从神经毒性转变为的时间表型转移缺血性损伤随着时间的推移神经保护作用。该提议的目的是研究CD11C-是否是否介导的信号传导增强了这些不同的功能或小胶质细胞的表型转移，并确定缺血性中风后CD11C+小胶质细胞在脑恢复中的潜在神经保护作用。 CD11C是一个整合素α链蛋白被广泛用作常规树突状细胞（CDC）的定义标记。 CD11C调节CDC的细胞粘附，迁移和吞噬活性。 CD11C介导的信号的作用在小胶质细胞中，缺血性中风后未知。转录组分析表明CD11C+小胶质细胞可能神经侮辱后起保护作用，但缺乏支持这种概念的实验证据。我们在CCR2+/RFP X CD11C-EYFP小鼠中进行了TMCAO，并观察到CD11C+的大幅增加 TMCAO后大脑中的小胶质细胞。我们的初步数据表明1）CD11C+小胶质细胞主要是 TMCAO后72小时出现在大脑侵权的边界上。这些小胶质细胞主要共同表达了激活标记IBA-1； 2）CD11C+ IBA-1+小胶质细胞迁移到并保持在 TMCAO后14天的神经胶质疤痕； 3）在第14天，CD11C+ IBA-1-小胶质细胞的子集出现在周期处大脑梗塞区域。在AIM 1中，我们假设小胶质细胞中的CD11C表达促进了大脑恢复通过将小胶质细胞迁移到梗塞核心，并增强其消除死细胞的能力。我们将使用与CD11C缺陷型小鼠交叉的CD11C-EYFP报告基因小鼠解决这一假设。的作用小胶质细胞中的CD11c在促进缺血性中风后促进大脑恢复中的CD11将由单一进一步确定细胞RNA测序。在AIM 2中，我们假设在慢性期消除CD11C+小胶质细胞缺血性损伤会增加脑梗塞并加剧神经系统缺陷。我们将检验这个假设使用骨髓嵌合体策略，其中CD11C+小胶质细胞将在小鼠中进行TMCAO 有选择地烧烤。阐明小胶质细胞从促炎转换为神经保护性可以帮助制定新型策略，以促进缺血性中风后神经恢复。