Lung transplant injury drives chronic lung allograft dysfunction via recruitment ofmonocyte-derived alveolar macrophages

项目摘要：对于许多晚期肺部疾病患者来说，肺移植仍然是唯一的 延长生命的可行治疗选择。然而，肺移植患者的5年存活率为54%，是最差的。 在实体器官移植的接受者中。慢性肺移植功能障碍(CLAD)是导致 肺或心肺移植后的发病率和远期死亡率。因此，生物标志物的识别和 新的治疗靶点对于预防或治疗肺移植后的包裹性和延长生存期是必不可少的。 虽然多个因素导致包裹性肺炎，但肺移植手术后的早期事件起着关键作用。 在为后续的着装搭建舞台的过程中发挥作用。这些包括手术创伤和缺血再灌注。 激活循环和常驻免疫细胞的损伤，继而是内皮损伤和免疫细胞 渗出。我们已经报道，单核细胞被招募到受损的肺中，可以建立长期的 并分化为致病的单核细胞来源的肺泡巨噬细胞。我们有因果关系 单核细胞来源的肺泡巨噬细胞对组织重塑和纤维化(类似包膜)的作用 删除策略。此外，使用无偏倚的单细胞转录图谱(rna-seq)对移植肺进行分析。 肺纤维化患者的组织和供体肺的活检(两者均在肺内获得 肺移植外科医生-Ankit Bharat，这项提议的关键贡献者)进行移植)，我们发现了一个 肺纤维化患者有独特的致病肺泡巨噬细胞群。 我们对单细胞rna-seq数据的计算分析表明，单核细胞来源的肺泡巨噬细胞 通过Plexin D1/信号被引导到其新的致病生态位，并由M-CSF/M- CSFR信令。与这一假设一致，靶向M-CSF/M-CSFR信号被特别消除 单核细胞来源的肺泡巨噬细胞和改善的病理。我们提供了来自MICE的初步数据 慢性同种异体肺移植功能障碍的模型和患者支持这一机制与CLAD的相关性。 因此，我们将使用小鼠模型和肺移植患者的样本来检验这一假设 致病的单核细胞来源的肺泡巨噬细胞，在移植周围损伤的最初阶段招募， 通过丛蛋白D1/信号素信号转导建立长期驻留，并通过M-CSF/M- CSFR信令在三个相互关联的目标中驱动： 目的1：确定移植肺中单核细胞来源的肺泡巨噬细胞是否被募集到 移植日由M-CSF/M-CSFR信号维持。 目的2：确定致病单核细胞来源的肺泡巨噬细胞是否定位于 肺纤维化通过网织蛋白D1/信号素信号转导途径实现。 目的3：确定异常的肺泡巨噬细胞的出现是否伴随着高表达的 早期CLAD患者BAL液中可检测到PLXND1和自分泌M-CSF/M-CSFR信号。

Project Summary: For many patients with advanced lung disease, lung transplantation remains the only viable therapeutic option to extend life. Yet the 5-year survival for lung transplant patients is 54%, the worst among solid organ transplant recipients. Chronic lung allograft dysfunction (CLAD) is the leading cause of morbidity and late mortality after lung or heart-lung transplantation. Hence, identification of biomarkers and novel therapeutic targets is essential to prevent or treat CLAD and extend survival after lung transplantation. While multiple factors contribute to CLAD, early events after the lung transplant procedure play a crucial role in setting the stage for subsequent CLAD. These include surgical trauma and ischemia-reperfusion injury that activates circulating and resident immune cells followed by the endothelial injury and immune cell extravasation. We have reported that monocytes, recruited to the injured lung, can establish a long-term residency and differentiate into pathogenic monocyte-derived alveolar macrophages. We have causally linked monocyte-derived alveolar macrophages to tissue-remodeling and fibrosis (resembling CLAD) using a genetic deletion strategy. Moreover, using unbiased single-cell transcriptomic profiling (RNA-seq) of explanted lung tissue from the patients with pulmonary fibrosis and biopsies of the donor lung (both obtained during lung transplantation by lung transplant surgeon – Ankit Bharat, key contributor to this proposal), we identified a distinct population of pathogenic alveolar macrophages exclusively present in patients with pulmonary fibrosis. Our computational analyses of single-cell RNA-seq data suggest that monocyte-derived alveolar macrophages are guided to their new pathogenic niches via plexin D1/signaling and are uniquely maintained by M-CSF/M- CSFR signaling. Consistent with this hypothesis, targeting M-CSF/M-CSFR signaling specifically eliminated monocyte-derived alveolar macrophages and ameliorated pathology. We present preliminary data from mouse models and patients with chronic lung allograft dysfunction supporting relevance of this mechanism for CLAD. We will thus use mouse models and samples from lung transplant patients to test the hypothesis that pathogenic monocyte-derived alveolar macrophages, recruited during the initial peri-transplant injury, establish long term residency via plexin D1/semaphorin signaling and are maintained via M-CSF/M- CSFR signaling to drive CLAD in three interrelated aims: Aim 1: To determine whether monocyte-derived alveolar macrophages recruited to the transplanted lung within day of the transplant are maintained by M-CSF/M-CSFR signaling. Aim 2: To determine whether pathogenic monocyte-derived alveolar macrophages are localized to regions of lung fibrosis lung via plexin D1/semaphorin signaling. Aim 3: To determine whether the emergence of aberrant alveolar macrophages with increased expression of PLXND1 and autocrine M-CSF/M-CSFR signaling can be identified in BAL fluid from patients with early CLAD.