Monocyte-Derived Microglia in Development and after Neonatal Brain Injury

项目摘要(摘要) 小胶质细胞曾被认为只起源于早期的卵黄囊祖细胞，但最近的研究提出 单核细胞来源的小胶质细胞在正常发育中的可能性，特别是在新生儿脑损伤后， 包括卒中、缺氧缺血(HI)和炎症/内毒素致敏的HI(LPS/HI)。然而，这一程度 单核细胞来源的小胶质细胞在正常发育中的作用尚不清楚，以及单核细胞来源的病理作用 小胶质细胞部分清晰可见。对这些问题的更好理解可能会摆脱机械性的见解，并建议 新生儿脑损伤的潜在治疗方法。我们将通过三个具体目标来解决这些问题。 在目标1中，我们将使用CCR2-CRE小鼠与R26R-EGFP小鼠杂交来确定其范围和分布 CCR2+单核细胞来源的小胶质细胞在大脑中的表达。 在目标2中，我们将使用PF-04136309(Ip)来抑制mcp1/ccr2介导的趋化作用或氯屈膦。 脂质体(IV)消融血源性单核细胞以评估其对新生儿的潜在益处 LPS/HI脑损伤。 在目标3中，我们将使用他莫昔芬剂量的CCR2-Creer；R26R-EGFP小鼠分离单核细胞来源的小胶质细胞- 类细胞在内毒素/HI损伤脑组织中寻找单细胞RNA-Seq负责的潜在效应因子 迟发性神经毒性和对突触网络的损害。

PROJECT SUMMARY (Abstract) Microglia were once thought derived exclusively from the early yolk sac progenitors, but recent studies raised the possibility of monocyte-derived microglia in normal development and particularly after neonatal brain injury, including stroke, hypoxia-ischemia (HI), and inflammation/LPS-sensitized HI (LPS/HI). However, the extent of monocyte-derived microglia in normal development is unknown, and the roles of monocyte-derived pathologic microglia partially defined. Better understanding of these issues may shed mechanistic insights and suggest potential treatments of neonatal brain injury. We will address these issues in three specific aims. In Aim 1, we will use CCR2-Cre mice crossed with R26R-EGFP mice to determine the extent and distributions of CCR2+ monocyte-derived microglia in the brain. In Aim 2, we will use PF-04136309 (IP) to inhibit the MCP1/CCR2-mediated chemoattraction or clodronate liposomes (IV) to ablate the blood-borne monocytes to assess their potential benefits against the neonatal LPS/HI brain injury. In Aim 3, we will use tamoxifen-dosed CCR2-CreER; R26R-EGFP mice to isolate monocyte-derived microglia- like cells in LPS/HI-injured brains for single-cell RNA-Seq to search for the potential effectors responsible for delayed neurotoxicity and damage to the synaptic network.