THE ROLE OF ISCHEMIA REPERFUSION INJURY IN LUNG ALLOGRAFT REJECTION

 描述（由申请人提供）：肺移植后的结局与其他移植物相比明显更差。缺血-再灌注损伤是一种炎症的嗜酸性形式，其抑制肺移植受者的短期和长期存活。这些观察结果使我们的小组把重点放在促进移植后中性粒细胞进入肺移植物的分子信号上。在上一个融资期，我们开发了 采用活体双光子显微镜分析通气小鼠原位肺移植物内实时中性粒细胞运输动力学的方法。这项技术创新使我们能够揭示单核细胞在中性粒细胞跨内皮迁移到再灌注肺移植物中的关键作用，并揭示中性粒细胞和其他肺移植细胞之间促进同种异体免疫的相互作用。在本申请中，我们建议检查调节肺移植物内中性粒细胞运输行为的先天免疫信号传导途径，以更好地了解这些细胞如何防止耐受。为此，在目标1中，我们将分析受体单核细胞和供体Dap 12（一种控制先天免疫信号传导的衔接分子）通过调节中性粒细胞募集在肺移植物损伤中的作用。我们将具体确定Dap 12是否通过控制巨噬细胞中细胞因子和趋化因子的产生来调节中性粒细胞跨内皮运输和耐受。在目标2中，我们提出了定义肺移植中坏死的作用，这是一种特殊形式的中性粒细胞对垂死细胞的趋化作用。为了实现这一目标，我们将分析FPR 1的作用，FPR 1是一种趋化因子受体，最近被证明可以控制坏死，以确定这种特定类型的中性粒细胞迁移行为是否控制跨上皮运输，进而促进调节CD 4 + T细胞极化和肺移植排斥反应的炎症信号。

 DESCRIPTION (provided by applicant): Outcomes after lung transplantation remain markedly worse compared to other grafts. Ischemia-reperfusion injury is a neutrophilic form of inflammation that inhibits both short and long-term survival of lung transplant recipients. These observations have led our group to focus on molecular signals that promote neutrophil trafficking into lung grafts following transplantation. In our previous funding period we developed methods to employ intravital 2-photon microscopy to analyze real-time neutrophil trafficking dynamics within ventilated mouse orthotopic lung grafts. This technical innovation allowed us to reveal the critical role that monocytes play in the neutrophil transendothelial migration into reperfused lung grafts and to uncover interactions between neutrophils and other lung graft cells that promote alloimmunity. In this application we propose to examine innate immune signaling pathways that regulate neutrophil trafficking behavior within lung grafts to better understand how these cells prevent tolerance. To this end in Aim 1 we will analyze the role of recipients monocytes and donor Dap12, an adaptor molecule that controls innate immune signaling, in lung graft injury through regulating neutrophil recruitment. We will specifically determine if Dap12 regulates neutrophil transendothelial trafficking and tolerance through controlling the production of cytokines and chemokines in macrophages. In Aim 2 we propose to define the role of necrotaxis in lung transplants, a specialized form of neutrophil chemotaxis towards dying cells. To execute this aim we will analyze the role of FPR1, a chemokine receptor recently shown to control necrotaxis, to determine if this specific type of neutrophil migratory behavior controls transepithelial trafficking and in turn promotes inflammatory signals that regulate CD4+ T cell polarization and lung transplant rejection.