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

• 批准号: 10350461
• 负责人: EDWIN CHI KEUNG WAN
• 金额: $ 22.8万
• 依托单位: WEST VIRGINIA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10350461
• 关键词: Address; Alteplase; Animal Model; Anti-Inflammatory Agents; Apoptotic; Area; Binding; Blood; Bone Marrow; Brain; Brain Infarction; Brain Injuries; Cell Adhesion; Cell physiology; Cells; Chimera organism; Chronic Phase; Cicatrix; Complement 3b; Data; Dendritic Cells; Disease; Excision; Genes; Goals; Heterogeneity; Hour; ITGAX gene; ITGB2 gene; Infarction; Inflammation; Inflammatory Response; Integrin alpha Chains; Integrin alphaXbeta2; Intercellular adhesion molecule 1; Interleukin-10; Ischemic Stroke; Mechanics; Mediating; Mediator of activation protein; 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; dimer; 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

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 目前对缺血性中风患者的治疗方案允许血液再灌流到大脑，但失败了 以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缺陷的新治疗策略是至关重要的。 需要的。神经元死亡诱导表达促炎介质的小胶质细胞激活，导致 缺血性卒中后脑损伤的加重。因此，靶向小胶质细胞被认为可以改善 中风后的脑损伤。然而，最近的研究表明，小胶质细胞的消除会增加大小 治疗脑梗塞并加重小鼠大脑中动脉短暂性闭塞后的神经功能障碍 (TMCAO)，一种研究缺血性中风的动物模型。这些数据表明了一种功能的异质性 小胶质细胞对缺血损伤的反应，或小胶质细胞从神经毒性到 缺血损伤后随时间推移的神经保护作用。这项提案的目标是调查CD11c- 介导的信号增强这些不同的功能或小胶质细胞的表型转变，并确定 CD11c+小胶质细胞在缺血性卒中后脑恢复中的潜在神经保护作用CD11c是一种 整合素α链蛋白，被广泛用作传统树突状细胞(CDCs)的定义标志。 CD11c调节CDC的细胞黏附、迁移和吞噬活性。CD11c介导的信号转导作用 在缺血性卒中后的小胶质细胞中的作用尚不清楚。转录组分析表明CD11c+小胶质细胞可能 在神经侮辱后起到保护作用，但缺乏实验证据来支持这一观点。 我们在CCR2+/RFP x CD11c-EYFP小鼠身上进行了tMCAO，观察到CD11c+显著增加 TMCAO后脑内的小胶质细胞。我们的初步数据显示：1)CD11c+小胶质细胞 TMCAO后72h出现脑梗塞边缘。这些小胶质细胞主要是 表达激活标记IBA-1；2)CD11c+IBA-1+小胶质细胞迁移到并维持在 3TMCAO后第14天，CD11c+IBA-1-小胶质细胞亚群在周围区出现。 大脑的梗死区。在目标1中，我们假设小胶质细胞中CD11c的表达促进了大脑的恢复 通过引导小胶质细胞迁移到梗死核心，并增强其清除死亡细胞的能力。我们 将使用CD11c-EYFP报告鼠与CD11c缺陷小鼠杂交来解决这一假说。的作用 小胶质细胞中CD11c在促进缺血性卒中后脑功能恢复中的作用将进一步通过单项实验确定。 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 脑缺血损伤后会增加脑梗塞，并加剧神经功能障碍。我们将检验这一假设 使用骨髓嵌合体策略，其中将对CD11c+小胶质细胞的小鼠进行tMCAO 选择性地消融。小胶质细胞从促炎向炎症转化的机制 神经保护可以帮助开发新的策略，促进缺血性中风后的神经恢复。