Reducing Fibroblast Persistence in Pulmonary Fibrosis as a Mechanism of Resolution

项目摘要 间质性肺疾病(ILD)包括一组破坏性的高密度纤维性实质性疾病。 发病率和死亡率，对此有效的治疗方法有限。ILD发展为肺纤维化(PF) 患者对肺泡上皮损伤的反应及随后活化和积聚的促纤维化 成纤维细胞，沉积胶原蛋白和其他细胞外基质(ECM)成分。积累性和 促纤维化成纤维细胞的持续性和细胞外基质的沉积导致进行性纤维化，从而导致 肺泡-毛细血管单位气体交换下降。吸入硅酸盐粉尘、香烟烟雾和有毒物质 化学品是已知的发展成纤维肺疾病的危险因素，这些暴露有 不成比例地影响了美国退伍军人、煤矿工人和建筑工人。Pf通常被认为是 不可逆转。因此，识别具有靶向性的分子途径变得越来越重要。 进行治疗干预。这项提案试图通过调查中央银行来解决这一未得到满足的需求 促纤维化成纤维细胞对细胞凋亡抵抗的发展有助于进展性 纤维性疾病。此外，我们认为抗凋亡基因Bcl-2的表达起着核心作用。 在调节促纤维化的成纤维细胞的持久性方面。基于对二氧化硅诱导的 肺纤维化模型，我们建议用3个特定目标来检验这一中心假说：特定目标1 将检验体内消融促纤维化的肺成纤维细胞将诱导持续性 由气管内注入二氧化硅微粒引起的肺纤维化。《特定目标2》将测试 假设降低促纤维化成纤维细胞对凋亡的抵抗性可促进 进行性肺纤维化。这一假设将使用基因方法进行检验，以确定 促纤维化成纤维细胞中抗凋亡基因Bcl-2的条件性缺失导致纤维化细胞的凋亡 二氧化硅诱导的肺纤维化模型中肺成纤维细胞与持续性纤维化的解决。 特异靶向3将检验这一假设，即临床相关的Bcl-2抑制剂将在治疗上靶向PRO-2。 纤维化成纤维细胞，促进已建立的肺纤维化的消退。这一假设将得到检验。 通过用小分子抑制剂治疗小鼠来降低Bcl-2的活性，防止成纤维细胞存活并促进 体内持续性纤维化的消退。小鼠将被跟踪使用微型CT成像来监测疾病 发展、进步和解决。拟议的研究将使人们对 以促纤维化成纤维细胞为死亡靶点，以及这可能如何有助于纤维化的解决。此外， 这项工作的结果应该会显著影响我们对控制 纤维化的消退及其在其他器官和组织中的持久性。

Project Summary Interstitial lung diseases (ILD) include a devastating group of fibrotic parenchymal diseases with high morbidity and mortality, for which there are limited effective therapies. Pulmonary fibrosis (PF) develops in ILD patients in response to alveolar epithelial injury and the subsequent activation and accumulation of pro-fibrotic fibroblasts, which deposit collagen and other extracellular matrix (ECM) components. The accumulation and persistence of pro-fibrotic fibroblasts and the deposition of ECM leads to progressive fibrosis resulting in declining gas exchange in the alveolar-capillary units. The inhalation of silicate dust, cigarette smoke and toxic chemicals are known risk factors for developing fibrotic lung disease and these exposures have disproportionally affected US veteran's, coal miners and construction workers. PF is generally believed to be irreversible. Consequently, it becomes increasingly important to identify molecular pathways that are targetable for therapeutic intervention. This proposal seeks to address this unmet need by investigating the central hypothesis that the development of pro-fibrotic fibroblast resistance to apoptosis contributes to progressive fibrotic disease. Furthermore, we propose that expression of the anti-apoptotic gene Bcl-2 plays a central role in mediating the persistence of pro-fibrotic fibroblasts. Based on robust preliminary studies in a silica-induced model of pulmonary fibrosis, we propose testing this central hypothesis with 3 specific aims: Specific Aim 1 will test the hypothesis that in vivo ablation of pro-fibrotic lung fibroblasts will induce the resolution of persistent pulmonary fibrosis initiated by the intratracheal instillation of silica particles. Specific Aim 2 will test the hypothesis that reducing the resistance to apoptosis in pro-fibrotic fibroblasts promotes the resolution of progressive pulmonary fibrosis. This hypothesis will be tested using a genetic approach to determine if conditional deletion of the anti-apoptotic gene Bcl-2 in pro-fibrotic fibroblasts leads to the apoptosis of fibrotic lung fibroblasts and the resolution of persistent fibrosis in a model of silica-induced pulmonary fibrosis. Specific Aim 3 will test the hypothesis that clinically relevant Bcl-2 inhibitors will therapeutically target pro- fibrotic fibroblasts and promote the resolution of established pulmonary fibrosis. This hypothesis will be tested by treating mice with a small molecule inhibitor to reduce Bcl-2 activity, prevent fibroblast survival and promote the resolution of persistent fibrosis in vivo. Mice will be followed using micro-CT imaging to monitor disease development, progression and resolution. The proposed studies will provide new understanding about the targeting of pro-fibrotic fibroblasts for death and how this may aid in the resolution of fibrosis. Furthermore, the outcome of this work should significantly impact our understanding of the mechanisms that control the resolution of fibrosis and its persistence in other organs and tissues.