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.

项目概要/摘要目前针对缺血性中风患者的治疗方案允许血液再灌注到大脑，但失败了解决导致中风幸存者长期身体和认知障碍的神经缺陷。因此，改善大脑恢复和解决神经功能缺陷的新治疗策略至关重要需要。神经元死亡会诱导表达促炎介质的小胶质细胞激活，从而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。然而，最近的研究表明，消除小胶质细胞会增加小胶质细胞的大小。脑梗死并加重小鼠短暂大脑中动脉闭塞后的神经功能缺损（tMCAO），用于缺血性中风研究的动物模型。这些数据表明功能异质性小胶质细胞对缺血性损伤的反应，或小胶质细胞从神经毒性到时间表型的转变缺血性损伤后随着时间的推移具有神经保护作用。该提案的目标是调查 CD11c- 介导的信号传导增强了小胶质细胞的这些不同功能或表型转变，并确定 CD11c+小胶质细胞在缺血性中风后大脑恢复中的潜在神经保护作用。 CD11c 是整合素 α 链蛋白，广泛用作传统树突状细胞 (cDC) 的定义标记。 CD11c 调节 cDC 的细胞粘附、迁移和吞噬活性。 CD11c 介导的信号传导的作用缺血性中风后小胶质细胞中的情况尚不清楚。转录组分析表明 CD11c+ 小胶质细胞可能在神经损伤后发挥保护作用，但缺乏支持这一观点的实验证据。我们对 Ccr2+/RFP x CD11c-EYFP 小鼠进行 tMCAO，观察到 CD11c+ 显着增加 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 tMCAO 后 72 小时出现在脑部梗死边缘。这些小胶质细胞主要共同表达激活标记IBA-1； 2) CD11c+ IBA-1+ 小胶质细胞迁移并维持在 tMCAO 后 14 天出现胶质疤痕； 3) 在第 14 天，CD11c+ IBA-1- 小胶质细胞的子集出现在周围大脑的梗塞区域。在目标 1 中，我们假设小胶质细胞中 CD11c 的表达促进大脑恢复通过引导小胶质细胞迁移到梗塞核心，并增强其消除死亡细胞的能力。我们将使用 CD11c-EYFP 报告小鼠与 CD11c 缺陷小鼠杂交来解决这一假设。的作用小胶质细胞中的 CD11c 在促进缺血性中风后大脑恢复方面的作用将通过单项进一步确定细胞RNA测序。在目标 2 中，我们假设慢性期 CD11c+ 小胶质细胞的消除缺血性损伤后会增加脑梗塞并加剧神经功能缺损。我们将检验这个假设使用骨髓嵌合体策略，其中将在 CD11c+ 小胶质细胞存在的小鼠中进行 tMCAO 选择性消融。阐明小胶质细胞从促炎转变为促炎的机制神经保护剂可以帮助开发促进缺血性中风后神经功能恢复的新策略。