Wnt-beta-catenin cross interactions in alveolar macrophages and epithelial cells in persistence of SSc-ILD

项目总结 系统性硬化症(SSC)是一种进行性纤维性疾病，目前尚无有效的治疗方法。 目前，SSc患者发病和死亡的主要原因是由于以下原因而导致的呼吸衰竭 肺纤维化。尽管间质性肺病(ILD)在SSc中发生得多么普遍，但它仍然很少。 了解并代表未得到满足的重大医疗需求。Wnt/-Catenin(-CAT)信号通路是 已知在整个发育和成年组织损伤后的修复过程中对细胞命运的决定至关重要。工作 Wnt/β-CAT通路在系统性红斑狼疮中被异常激活。 硬化症和相关的ILD。我们实验室的后续研究提供了第一个证据 Wnt共同受体LRP5的全球遗传缺失导致β-CAT信号的减少，对 博莱霉素诱导的肺纤维化及外周血单个核细胞的变化 特发性肺纤维化(IPF)患者的独立队列，Wnt信号是最常见的两种信号之一。 代表了与预后恶化相关的途径。我们已经生成了大量的初步数据 肺巨噬细胞持续的β-CAT信号转导促进肺纤维化的持续性 在博莱霉素和石棉诱导的小鼠损伤后，表明巨噬细胞是关键细胞 -CAT信号通过其驱动纤维化的类型。我们的初步数据还显示，肺泡 在SSC-ILD肺中巨噬细胞数量增加，其中SSC-ILD和IPF的肺转录 受试者有共同的基因。因此，基于这些发现，我们推断，驱动 组织损伤后巨噬细胞的募集、分化和耐受在纤维化中是保守的 疾病通过一个共同的WNT/-CAT调节轴。我们假设需要WNT/-CAT信令 单核细胞分化为肺泡巨噬细胞及损伤肺泡 上皮细胞提供了一种上下文Wnt信号，维持了这些被招募的人的促纤维化环境 巨噬细胞，从而加重肺修复，促进纤维化的持久性。我们建议1) 确定Wnt/β-CAT信号在单核-巨噬细胞分化中的作用 纤维化在SSC-ILD中的作用，2)确定损伤的肺泡上皮细胞中Wnt信号的作用 维持SSC-ILD中促纤维化的巨噬细胞表型，以及3)测定单核细胞- SSC-ILD受试者的巨噬细胞亚群表达Wnt途径基因的浓缩。 我们将使用患有SSc-ILD和体内互补的受试者的血液和肺样本 使用竞争和屏蔽嵌合小鼠、巨噬细胞特异性转基因小鼠靶向的方法 β-CAT和WNT配体，以及化学消融来分析WNT/β-CAT信号的相对贡献。 肺损伤后修复所需的巨噬细胞和上皮细胞以及免疫的SSc-ILD 路径也有牵连。

Project summary Systemic sclerosis (SSc) is a progressive fibrotic disease for which there is no effective treatment. Presently, the major cause of morbidity and mortality for patients with SSc is respiratory failure due to pulmonary fibrosis. Despite how commonly interstitial lung disease (ILD) occurs in SSc, it remains poorly understood and represents a major unmet medical need. The Wnt/-catenin (-cat) signaling pathway is known to be crucial for cell fate decisions throughout development and adult tissue repair after injury. Work from our group and others have shown that the Wnt/β-cat pathway is aberrantly activated in systemic sclerosis and the associated ILD. Subsequent studies from our laboratory provided the first evidence that global genetic loss of the Wnt co-receptor Lrp5, resulting in reduced β-cat signaling, was protective against bleomycin-induced pulmonary fibrosis and that, in the peripheral blood mononuclear cells from two independent cohorts of Idiopathic Pulmonary Fibrosis (IPF) subjects, Wnt signaling as one of the top 2 over- represented pathways associated with worsened prognosis. We have generated extensive preliminary data demonstrating that sustained β-cat signaling in lung macrophages promotes the persistence of lung fibrosis after both bleomycin- and asbestos-induced injuries in mice, suggesting that macrophages are a key cell type through which -cat signaling drives fibrosis. Our preliminary data also reveal that the alveolar macrophage population is increased in SSc-ILD lungs, where lung transcriptomes from SSc-ILD and IPF subjects share common genes. Thus, based on these findings, we reason that the signals that drive macrophage recruitment, differentiation and perdurance after tissue injury are conserved across fibrotic diseases through a common Wnt/-cat regulatory axis. We hypothesize that Wnt/-cat signaling is required for the differentiation of monocytes into recruited alveolar macrophages and that injured lung alveolar epithelium provides a contextual Wnt signal that maintains a pro-fibrotic milieu for these recruited macrophages, thus aggravating lung repair and promoting the persistence of fibrosis. We propose 1) to determine the role Wnt/β-cat signaling to the differentiation of monocytes-macrophages in the persistence of fibrosis in SSc-ILD, 2) to determine the contribution of Wnt signaling from the injured alveolar epithelium in maintaining the pro-fibrotic macrophage phenotype in SSc-ILD, and 3) to determine the monocyte- macrophage subpopulations from subjects with SSc-ILD that express enrichment for Wnt pathway genes. We will use human blood and lung samples from subjects with SSc-ILD and complementary in vivo approaches using competitive and shielded chimeric mice, macrophage-specific transgenic mice targeting β-cat and Wnt ligands, and chemical ablation to dissect the relative contributions of Wnt/β-cat signaling in macrophages and epithelial cells necessary for repair after lung injury and in SSc-ILD where immune pathways are implicated.