Myeloid lineage targeting to improve recovery from injury and surgery: Cellular and molecular mechanisms

项目摘要 尽管每年有多少人受到持续疼痛和非致命性骨折愈合不良的影响 创伤和手术损伤目前仍不清楚哪些是深刻的多细胞的关键成分 对受伤的反应，以及如何利用这些反应来改善结果。尤其是外周损伤 动员免疫系统来解决组织损伤，然而，持续的免疫激活可以 这是有害的，并且会导致延迟愈合。髓系细胞在先天免疫中起重要作用 对损伤的反应--外围为巨噬细胞，中央为卵黄囊来源的小胶质细胞。尽管如此， 髓系细胞在骨愈合、围手术期疼痛中的颞区和间隔区特异性作用 手术恢复情况尚不清楚。精确操纵这些髓系细胞以建立 在人类身上，因果关系是不可能的。为了确定提高恢复的细胞和分子靶点，我们将 因此，利用临床上了解情况的小鼠骨科损伤模型。我们的中心假设是 有一个关键时期，在此期间，髓系细胞的参与是恢复正常的关键 损伤；然而，以细胞因子释放和体内平衡功能丧失为标志的长期激活可以 会导致疼痛和骨骼愈合受损，最终增加长期残疾的风险。为了追求这一点 基础工作，我们将使用分子和整体有机体相结合的方法，我们在 重要的专业知识包括复杂骨科创伤的小鼠模型，情感动机读数 持续性疼痛和功能障碍、特定的转基因操作和骨的纵向成像 和中枢神经系统组织。特别是，这种能力的融合使我们能够回答以下关键问题 知识鸿沟：1)先天免疫反应有助于康复，但它的功能障碍 在体内监测以识别高危个体？2)激活的髓系细胞的具体分子特征是什么- 血统细胞可以在外周和中心定位以改善预后？3)髓系反应 周围损伤在进化上是保守的，因此在翻译上是相关的？拟议的研究建立了 在我们之前在慢性疼痛小鼠模型中所做的工作中，我们表明：1)髓样靶向正电子 放射断层扫描配体可以追踪功能失调的先天免疫激活，2)巨噬细胞的减弱 小胶质细胞的激活可以改善持续性疼痛，3)新的标志物可以用来区分浸润性疼痛 巨噬细胞来自脊髓内驻留的小胶质细胞，从而阐明了它们的独特贡献。最终， 这些研究将确定髓系细胞可能是外周损伤之间的最初细胞联系， 骨性愈合差，剧烈急性疼痛。成功完成拟议的研究将加强我们的 了解脑室特异性巨噬细胞和小胶质细胞在创伤后愈合中的作用，鉴定细胞- 明确干预的具体目标，并澄清这种治疗将在何时和在谁身上提供最大的好处。

Project Summary Despite the number of people affected each year by persistent pain and poorly healed fractures after nonfatal traumatic and surgical injury it remains unclear what are the key components of the profound multicellular response to injury and how they can be manipulated to improve outcomes. In particular, peripheral injury mobilizes the immune system to resolve tissue damage, however, sustained immune activation can be detrimental and contribute to delayed healing. Myeloid-lineage cells are instrumental in the innate immune response to injury- peripherally, as macrophages, and centrally, as yolk sac-derived microglia. Nevertheless, the temporal and compartment-specific contributions of myeloid-lineage cells to bone healing, perioperative pain and surgical recovery have yet to be elucidated. Precise manipulation of these myeloid-lineage cells to establish causation is not possible in humans. To identify cellular and molecular targets for improving recovery we will therefore take advantage of a clinically informed mouse model of orthopaedic injury. Our central hypothesis is that there is a critical period during which myeloid-lineage cell involvement is crucial for proper recovery from injury; however, prolonged activation, marked by cytokine release and loss of homeostatic functions, can contribute to pain and impaired bone healing ultimately increasing the risk for long-term disability. To pursue this fundamental work, we will use a combination of molecular and whole organism approaches in which we have significant expertise including mouse models of complex orthopaedic trauma, affective-motivational readouts of persistent pain and functional impairment, specific transgenic manipulations and longitudinal imaging of bone and CNS tissues. In particular, this convergence of capabilities uniquely positions us to answer the following key knowledge gaps: 1) The innate immune response is instrumental to recovery, but can its dysfunction be monitored in vivo to identify at risk individuals? 2) What specific molecular signatures of activated myeloid- lineage cells can be targeted peripherally and centrally to improve outcomes? 3) Is the myeloid-lineage response to peripheral injury evolutionarily conserved and therefore translationally relevant? The proposed research builds on our previous work in a mouse model of chronic pain in which we showed that: 1) Myeloid-targeted positron emission tomography ligands can track dysfunctional innate immune activation, 2) Attenuation of macrophage and microglial activation can improve persistent pain, 3) New markers can be used to distinguish infiltrating macrophages from resident microglia in the spinal cord thus clarifying their unique contributions. Ultimately, these studies will establish how myeloid-lineage cells may be the initial cellular link between peripheral injury, poor bone healing and severe acute pain. Successful completion of the proposed studies will enhance our understanding of compartment-specific macrophage and microglia effects on healing after injury, identify cell- specific targets for intervention, and clarify when and in whom such treatments will provide the most benefit.