Immunogenomic analysis of donor lung injury and its impact on clinical outcomes after lung transplantation

肺移植（LT）后最初几天内发生的肺损伤的严重程度是一个关键因素， LT受者死亡或慢性肺移植早期发展风险最高指标 功能障碍事实上，30%被认为适合LT的肺迅速发展为严重的肺损伤，这表明， 在供体肺中可能已经存在未被识别的亚临床损伤， 一个关键的未满足的需求是提高检测和解释的能力， 亚临床供体肺损伤的后果可能导致LT后临床结局不良。 R 01提案，一个有成就的医生科学家将开发一个新的研究领域，调查如何 亚临床供体肺损伤触发最终导致CLAD的级联事件。最近的研究 将供体来源的细胞游离DNA（cfDNA）鉴定为肺同种异体移植物损伤的生物标志物， 在临床识别急性排斥反应之前检测到。然而，尚不清楚哪些特定的细胞和损伤 这些机制导致cfDNA从供体肺释放。cfDNA还可以机械地加重肺损伤。 炎症在非LT肺损伤模型中，支气管肺泡灌洗液或血浆中的cfDNA检测激活了 干扰素基因刺激因子（STING）。STING然后通过以下方式促进持续的失调炎症： 激活以前参与LT后肺损伤的炎症通路，包括NF-κ B B、NLRP 3和 MKLK。在本Katz R 01提案中，一名具有LT临床专业知识和科学专业知识的ESI医生科学家 在ARDS的动物模型中提出了一种确定供体肺损伤机制的综合方法， 使用单细胞基因组学和基于CyTOF的免疫细胞， 来自人供体肺的系列样品与新的亚临床肺损伤多击小鼠模型的分析 供体肺损伤，我们将确定特定的细胞和分子机制，通过供体肺 损伤影响早期移植物功能障碍。我们假设亚临床供体肺损伤导致严重的 通过将供体来源的cfDNA释放到同种异体移植物空间中，触发前馈， 炎症循环和持续的细胞损伤导致不良的临床结果。具体目标是： (1)为了测试亚临床供体肺损伤是否与供体来源的cfDNA的释放相关，以及亚临床供体肺损伤是否与供体来源的cfDNA的释放相关。 在人类中的临床结果，使用单细胞RNA测序和大量细胞术对供体肺活检进行分析 在LT之前和之后收集和（2）使用在LT之前的连续亚临床肺损伤的新动物模型， 缺血再灌注，以确定亚临床供体肺损伤如何释放cfDNA以使供体肺 在缺血再灌注损伤后发生过度的STING依赖性炎症。统称 结合纵向人类观察数据和机制小鼠实验实现了一个主要的 LT研究中的差距，并将提供广泛的基础知识来了解亚临床供体肺如何 损伤在细胞和分子水平上影响临床结果。

The severity of lung injury that develops within the first several days after lung transplantation (LT) is a key indicator of which LT recipients are at greatest risk of death or early development of chronic lung allograft dysfunction. The fact that 30% of lungs deemed suitable for LT rapidly develop severe lung injury suggests that there may be unrecognized subclinical injury already present in donor lungs that renders the lung allograft susceptible to further injury at the time of LT. A critical unmet need is improved ability to detect and interpret the consequences of subclinical donor lung injury that may drive poor clinical outcomes after LT. In this Katz R01 proposal, an accomplished physician scientist will develop a new area of research investigating how subclinical donor lung injury triggers a cascade of events that ultimately results in CLAD. Recent studies have identified donor-derived cell-free DNA (cfDNA) as a biomarker of lung allograft injury, with increased cfDNA detected prior to clinical recognition of acute rejection. However, it is unknown which specific cells and injury mechanisms cause cfDNA release from the donor lung. cfDNA can also mechanistically exacerbate lung inflammation. In models of non-LT lung injury, cfDNA detection in bronchoalveolar lavage or plasma activates the stimulator of interferon genes (STING). STING then promotes ongoing dysregulated inflammation by activating inflammatory pathways previously implicated in lung injury after LT, including NF-B, NLRP3, and MKLK. In this Katz R01 proposal, an ESI physician scientist with clinical expertise in LT and scientific expertise in animal models of ARDS proposes an integrated approach to define mechanisms of donor lung injury that drive cfDNA release and poor outcomes after LT. Using single-cell genomics and CyTOF-based immune cell profiling of serial samples from human donor lungs coupled with a new multi-hit murine model of subclinical donor lung injury, we will determine the specific cellular and molecular mechanisms through which donor lung injury affects early allograft dysfunction. We hypothesize that subclinical donor lung injury drives severe allograft injury through release of donor-derived cfDNA into the allograft airspace, triggering a feed-forward cycle of inflammation and ongoing cellular injury that results in poor clinical outcomes. The Specific Aims are: (1) to test whether subclinical donor lung injury is associated with release of donor-derived cfDNA and poor clinical outcomes in humans, using single-cell RNA sequencing and mass cytometry on donor lung biopsies collected before and after LT and (2) to use a novel animal model of sequential subclinical lung injury prior to ischemia reperfusion to determine how subclinical donor lung injury releases cfDNA to prime the donor lung to develop excessive STING-dependent inflammation after ischemia-reperfusion injury. Together, the combination of longitudinal human observational data and mechanistic murine experimentation fulfills a major gap in LT research and will provide a broad foundational knowledge to understand how subclinical donor lung injury affects clinical outcomes at the cellular and molecular level.