Dynamic Cellular Interactions Associated with Inflammatory Monocyte Accumulation in the Neurovasculature with Social Stress

项目总监/主要研究者（谢里丹，JF & Godbout JP）： 项目总结/摘要： 大脑中的动态炎症信号可能在焦虑中起着致病作用。我们报告说， 小鼠的社交失败（RSD）诱导交感神经介导的致敏单核细胞从骨髓中释放 被积极地招募到大脑中。总的来说，我们发现RSD促进了长时间的焦虑样 依赖于小胶质细胞激活和炎症单核细胞募集以威胁评估的行为 大脑的各个区域。本申请证明了产生IL-1β的单核细胞的小胶质细胞募集， 神经血管内皮细胞是必要的增强焦虑样行为的反应，社会 应力尽管有这些知识，三个关键的机械问题仍然有待回答，这将允许 开发新的干预措施来治疗与压力相关的神经精神并发症： 1)RSD如何激活威胁评估区域中的小胶质细胞？2)炎症性单核细胞 选择性招募到神经血管内皮细胞的威胁评估区域？3)关键因素是什么 是由神经血管内皮细胞产生的，会增强神经炎症和焦虑？我们证明了 响应于RSD的小胶质细胞活化取决于威胁评估区域内的神经元活化。 此外，初步证据表明，这是由嘌呤能受体P2 RX 7的激活介导的， 关于小胶质细胞。本文提供的新数据表明，单核细胞募集和焦虑样 RSD后的行为需要小胶质细胞活化。此外，细胞特异性转录谱表明， 小胶质细胞通过趋化因子配体（CCL 2）分泌将单核细胞募集到大脑中。这些被招募 单核细胞通过内皮IL-1受体-1激活产生IL-1 β并促进焦虑样行为。值得注意的是， 这种IL-1 R1激活与COX 2的神经血管表达增加有关，COX 2是一种酶， 合成具有神经活性的野牡丹素。因此，本项目的目标是测试假设，招聘 随后炎症单核细胞与神经血管内皮细胞的相互作用对于 RSD后神经炎症增加和焦虑样行为增强。为了解决这个 假设，提出了三个具体目标。在Aim-1中，我们将确定RSD引起的 小胶质细胞的活化依赖于P2 RX 7嘌呤能受体的刺激。在Aim-2中，我们将确定 单核细胞募集到威胁评估所需的小胶质细胞产生CCL 2的程度 区域和RSD后焦虑样行为的诱导。在Aim-3中，我们将评估内皮细胞的作用， COX 2的表达，并确定IL-1 R1刺激的内皮细胞产生的其他关键因子， 促进RSD后的焦虑样行为。了解小胶质细胞募集如何产生IL-1β 单核细胞威胁评估区域加强神经炎症和焦虑样行为将导致新的 干预与压力相关的神经精神并发症。 PHS 398/2590（Rev.06/09）

Program Director/Principal Investigator (Sheridan, JF & Godbout JP): PROJECT SUMMARY/ABSTRACT: Dynamic inflammatory signaling in the brain may have a causative role in anxiety. We report that repeated social defeat (RSD) in mice induces sympathetic-mediated release of primed monocytes from the bone marrow that are actively recruited to the brain. Collectively, we show that RSD promotes prolonged anxiety-like behavior that depends on activation of microglia and recruitment of inflammatory monocytes to threat appraisal regions of the brain. This application demonstrates that microglial recruitment of IL-1β producing monocytes to neurovascular endothelium is necessary for the potentiation of anxiety-like behavior in response to social stress. Despite this knowledge, three key mechanistic questions remain to be answered, which will allow for the development of novel interventions for treatment of neuropsychiatric complications associated with stress: 1) How does RSD activate microglia in threat appraisal regions? 2) How are inflammatory monocytes selectivity recruited to neurovascular endothelium in threat appraisal regions? 3) What are the key factors produced by neurovascular endothelia cells that potentiate neuroinflammation and anxiety? We show that microglial activation in response to RSD depends on neuronal activation within threat appraisal regions. Moreover, preliminary evidence suggests that this is mediated by activation of the purinergic receptor, P2RX7, on microglia. Novel data presented here show that monocyte recruitment and the development of anxiety-like behavior after RSD requires microglial activation. Furthermore, cell-specific transcriptional profiling indicates that microglia recruit monocytes to the brain via chemokine ligand (CCL2) secretion. These recruited monocytes produce IL-1and promote anxiety-like behavior by endothelial IL-1 Receptor-1 activation. Notably, this IL-1R1 activation is associated with increased neurovascular expression of COX2, the enzyme that synthesizes neuroactive prostaglandins. Thus, the goal of this project is to test the hypothesis that recruitment and subsequent interaction of inflammatory monocytes with neurovascular endothelial cells is critical for the augmentation of neuroinflammation and potentiation of anxiety-like behavior following RSD. To address this hypothesis, three specific aims are proposed. In Aim-1, we will ascertain the extent to which RSD-induced microglial activation is dependent on stimulation of the P2RX7 purinergic receptor. In Aim-2, we will determine the degree to which microglial production of CCL2 is required for monocyte recruitment to threat appraisal regions and the induction of anxiety-like behavior after RSD. In Aim-3, we will assess the role of endothelial COX2 following RSD and determine other key factors produced by IL-1R1-stimulated endothelial cells that facilitate anxiety-like behavior after RSD. Understanding how microglial recruitment of IL-1β producing monocytes to threat appraisal regions potentiates neuroinflammation and anxiety-like behavior will lead to new interventions for neuropsychiatric complications associated with stress. PHS 398/2590 (Rev. 06/09) Page Continuation Format Page