Targeting Foxm1 in pulmonary fibrosis

项目总结。 现有的肺纤维化治疗方法并未显著提高存活率；迫切需要 新方法。环境和遗传因素的组合创造了一种肺泡上皮， 易受伤的易受伤害的对受损组织的松弛修复导致肺泡的增生和增殖 第二类细胞(AECII)--所谓的“重新编程”的AECII，这是肺部的主要病理特征 肝纤维化患者的比例。重新编程的AECII在肺纤维化的发病机制中起着关键作用， 产生转化生长因子-和促炎介质，导致肺成纤维细胞活化和募集 巨噬细胞进一步解除对修复的调控。我们的长期目标是剖析转录调控 肺纤维化。我们最近发现了一种新的促纤维化调节因子FOXM1，它是 叉头盒(FOX)转录因子。我们的初步数据表明FOXM1在AECII中被诱导 在人和小鼠肺的正常肺泡区内，而不是在纤维化病变内，表明FOXM1可以 成为重新编程的AECII的标志。激活的FOXM1转录本在小鼠AECII中的转基因表达 加重放射性肺炎，并导致严重的肺纤维化。有条件地删除 AECII来源的FOXM1可减轻放射性肺纤维化。虽然这些数据表明AECII 通过FOXM1介导的事件促进肺纤维化，下游信号通路受 AECII中的FOXM1有待鉴定(目标)。我们将检验重新编程的增生性疾病的假说 AECII通过FOXM1介导的成纤维细胞活化和募集促进肺纤维化 骨髓炎性细胞转化为纤维化病变。通过结合遗传和药理学方法 在辐射和博莱霉素诱导的小鼠肺纤维化模型中，拟议的研究将确定分子 FOXM1在AECII中的调控机制及增生性FOXM1阳性AECII对AECII的作用 凌氏纤维化。在目标1中，我们将确定FOXM1阳性的AECII在成纤维细胞激活中的作用。vbl.使用 带有FOXM1功能获得和功能丧失的转基因小鼠及AECII的单细胞RNA序列分析 我们将从人肺间质纤维化中分离出FOXM1靶基因。因为我们的初步数据显示 促纤维化和炎性介质在FOXM1过表达的AECII中的表达，我们将检测 FOXM_1是否激活血管内皮细胞骨桥蛋白和转化生长因子β-1基因的转录并刺激其活化 潜伏的转化生长因子β1蛋白，导致肺成纤维细胞的激活。在目标2中，我们将检查FOXM1是否激活 AECII中的CCL2和CXCL5基因导致髓系炎症细胞重新聚集到纤维化的肺中。在……里面 目的3，我们将使用我实验室最近发现的新的小分子FOXM1抑制剂来抑制AECII 肺纤维化小鼠模型中的重新编程、肺炎症和纤维化重塑。 我们研究的完成将：(1)确定FOXM1诱导肺损伤的新的分子机制 以及(2)新型FOXM1抑制剂在肺纤维化中的疗效测试。

PROJECT SUMMARY. Existing treatments for pulmonary fibrosis have not significantly improved survival; there is a critical need for new approaches. A combination of environmental and genetic factors creates an alveolar epithelium that is susceptible to injury. Deregulated repair of damaged tissue leads to the hyperplastic and proliferating alveolar type II cells (AECII) – the so called “re-programmed” AECII, which are main pathological features in the lungs of patients with fibrosis. Re-programmed AECIIs play a key role in the pathogenesis of pulmonary fibrosis, producing TGF- and pro-inflammatory mediators leading to activation of lung fibroblasts and recruitment of macrophages that further deregulate repair. Our long-term goal is to dissect transcriptional regulation of pulmonary fibrosis. We recently identified a novel pro-fibrotic regulator, Foxm1, a member of the family of Forkhead Box (Fox) transcription factors. Our preliminary data demonstrated that Foxm1 is induced in AECII within fibrotic lesions, but not in normal alveolar region of human and mouse lungs, indicating that Foxm1 can be a marker of re-programmed AECIIs. Transgenic expression of activated Foxm1 transcript in mouse AECII exacerbated radiation-induced pneumonitis and caused severe pulmonary fibrosis. Conditional deletion of Foxm1 from AECII attenuated radiation-induced lung fibrosis. While these data demonstrate that AECII promote pulmonary fibrosis through Foxm1-mediated events, the downstream signaling pathways regulated by Foxm1 in AECII remain to be identified (objective). We will test hypothesis that reprogrammed hyperplastic AECII promote pulmonary fibrosis through Foxm1-mediated activation of fibroblasts and recruitment of myeloid inflammatory cells into fibrotic lesions. By combining genetic and pharmacological approaches in radiation- and bleomycin-induced mouse models of lung fibrosis, the proposed studies will identify molecular mechanisms regulated by Foxm1 in AECII, and determine contribution of hyperplastic Foxm1-positive AECII to ling fibrogenesis. In Aim 1, we will determine the role of Foxm1-positive AECII in activation of fibroblasts. Using transgenic mice with Foxm1 gain-of-function and loss-of-function, and single cell RNA-seq analysis of AECII isolated from human IPF lungs, we will identify Foxm1 target genes. Since our preliminary data show increased expression of pro-fibrotic and inflammatory mediators in Foxm1-overexpressing AECII, we will examine whether Foxm1 activates transcription of Osteopontin and TGFβ1 genes in AECII, and stimulates activation of latent TGFβ1 protein, causing activation of lung fibroblasts. In Aim 2, we will examine whether Foxm1 activates CCL2 and CXCL5 genes in AECII, leading to recruitment of myeloid inflammatory cells into fibrotic lungs. In Aim 3, we will use novel small molecule Foxm1 inhibitor recently discovered in my laboratory to inhibit AECII re-programming, lung inflammation and fibrotic remodeling in murine models of pulmonary fibrosis. Completion of our studies will (1) identify novel molecular mechanisms whereby Foxm1 induces pulmonary fibrosis, and (2) test efficacy of novel Foxm1 inhibitors in lung fibrosis.