Targeting CCR2 (CC Chemokine Receptor 2) to treat TBI

 描述(由申请人提供)： 颅脑损伤后的神经炎症加剧了神经元和神经胶质细胞的死亡和功能障碍。单核细胞来源的巨噬细胞反应在脑外伤中是有害的。然而，巨噬细胞是一个广泛的异质性群体，极化的亚群对伤口修复至关重要。我们的目标是确定对脑外伤的先天免疫反应的有害和有益成分，并确定它们何时出现，确定治疗干预的最佳靶点和时机。这个 最终目标是阻止有害反应并加强修复反应，以改善脑外伤的长期功能结果。我们最近发表的研究表明，CCR2-/-小鼠减少了单核细胞来源的脑巨噬细胞，并改善了脑损伤后的预后。我们假设药物阻断人CCR2将改善脑损伤。我们的新数据显示，CCR2拮抗剂CCX872(肾病II期临床试验)在表达人CCR2的小鼠脑损伤后5分钟给予CCX872，可阻断83±2%的巨噬细胞浸润。目的1.确定脑创伤后给予人CCR2拮抗剂CCX872对表达人CCR2的小鼠的治疗效果，以抑制巨噬细胞向脑内的渗透，改善病理和行为学结果。1A.确定脑创伤后给予hCCR2拮抗剂CCX872阻断巨噬细胞向脑内渗透的有效剂量范围和时间窗。1B.确定脑创伤后给予hCCR2拮抗剂CCX872改善行为功能和组织病理学的有效剂量范围和时间窗。我们之前发表的工作和我们新的单细胞RNA测序研究表明，脑损伤巨噬细胞是多样化的，并不局限于M1/M2范式。我们假设在脑外伤后出现了多个单核细胞来源的巨噬细胞和小胶质细胞亚群。目的2.通过单细胞全转录组分析，明确脑损伤后脑内单核细胞来源的巨噬细胞和驻留的小胶质细胞的多样性。2A。通过进行单细胞RNA测序，确定脑损伤后单核细胞来源的脑巨噬细胞亚群。2B。通过进行单细胞RNA测序，确定脑损伤后小胶质细胞亚群。在没有CCR2的情况下，脑损伤后巨噬细胞亚群仍然渗透到受损的大脑中，并与改善预后有关。我们假设CCR2非依赖的巨噬细胞在脑损伤中具有保护作用。目的3.确定脑创伤后CCR2非依赖性巨噬细胞的表达谱、功能作用和需求。3A.用单细胞RNA序列确定脑创伤后CCR2非依赖性巨噬细胞亚群。3B.通过检测巨噬细胞的吞噬功能、细胞因子的产生和T细胞抑制功能来确定CCR2非依赖性巨噬细胞对脑损伤的反应的功能性质。3C。确定CCR2非依赖性巨噬细胞是有益的还是有害的，方法是用氯屈膦酸盐脂质体在脑损伤后的CCR2-/-小鼠体内耗尽巨噬细胞，并确定其对脑损伤预后的影响。这项工作将为靶向CCR2用于脑外伤治疗提供临床前基础和设计。此外，这项工作将在脑外伤的特定背景下提供一个前所未有的巨噬细胞生物学的视角。这些研究将导致知情的方法来改变神经炎症，以改善退伍军人的结果。

 DESCRIPTION (provided by applicant): Neuroinflammation following TBI exacerbates neuronal and glial death and dysfunction. The monocyte- derived macrophage response is harmful in TBI. However, macrophages are a broadly heterogeneous population and polarized subsets can be critical for wound repair. Our goal is to identify harmful and beneficial components of the innate immune response to TBI and to define when they arise, to identify optimal targets and timing for therapeutic intervention. The ultimate goal is to block harmful responses and enhance reparative ones to improve long-term functional outcomes of TBI. Our recently published study showed that Ccr2-/- mice had reduced monocyte-derived brain macrophages and improved outcomes post-TBI. We hypothesize that pharmacological blockade of human CCR2 will improve TBI. Our new data shows that a CCR2 antagonist, CCX872 (in Phase II clinical trials for nephropathy), given 5 min after TBI in mice expressing human CCR2 blocked 83±2% of the macrophage infiltrate. Aim 1. Determine the therapeutic benefit of the human CCR2 antagonist, CCX872, given after TBI, to mice expressing human CCR2 to inhibit macrophage infiltration into the brain, and to improve pathologic and behavioral outcomes. 1a. Determine the effective dose range and time window of hCCR2 antagonist, CCX872, administered after TBI to block macrophage infiltration to the brain. 1b. Determine the effective dose range and time window of hCCR2 antagonist, CCX872, administered after TBI to improve behavioral functions and histopathology. Our previous published work and our new preliminary single-cell RNA sequencing studies indicate that TBI macrophages are diverse and are not limited to the M1/M2 paradigm. We hypothesize that multiple monocyte- derived macrophages and microglia subsets develop after TBI. Aim 2. Define the diversity of monocyte-derived macrophages and resident microglia in the brain post- TBI by the use of single-cell, whole-transcriptome analysis. 2a. Define the monocyte-derived brain macrophage subsets post-TBI by performing single-cell RNA seq. 2b. Define microglia subsets post-TBI by performing single-cell RNA seq. In the absence of CCR2, a macrophages subset still infiltrates the injured brain after TBI, and is associated with improved outcomes. We hypothesize that CCR2-independent macrophages are protective in TBI. Aim 3. Determine the expression profile, functional role, and requirement for CCR2-independent macrophages in post-TBI outcomes. 3a. Define CCR2-independent macrophage subsets in the brain after TBI by single-cell RNA seq. 3b. Define the functional nature of the CCR2-independent macrophage response to TBI by examining phagocytosis, cytokine production, and T cell suppressor function by these cells. 3c. Determine if CCR2-independent macrophages are beneficial or harmful by depleting them with clodronate liposomes in Ccr2-/- mice after TBI and determining the effects on TBI outcomes. This work will provide the preclinical basis and design for targeting CCR2 in TBI therapy. Furthermore, the work will provide an unprecedented view of macrophage biology in the specific context of TBI. These studies will lead to informed approaches for altering neuroinflammation to improve outcomes for veterans.