Reducing Fibroblast Persistence in Pulmonary Fibrosis as a Mechanism of Resolution

项目摘要 间质性肺疾病（ILD）包括一组破坏性的纤维化实质疾病，具有高的肺功能。 发病率和死亡率，对此有效的治疗方法有限。ILD中发生肺纤维化（PF） 患者对肺泡上皮损伤以及随后的促纤维化因子的激活和积累的反应 成纤维细胞，其沉积存款胶原和其他细胞外基质（ECM）组分。积累和 促纤维化成纤维细胞的持续存在和ECM的沉积导致进行性纤维化， 肺泡-毛细血管单位的气体交换下降。吸入硅酸盐粉尘、香烟烟雾和有毒物质 化学物质是已知的发展纤维化肺病的危险因素， 美国退伍军人、煤矿工人和建筑工人受到严重影响。一般认为PF是 不可逆的因此，识别可靶向的分子途径变得越来越重要 进行治疗干预。该提案旨在通过调查中央 假设促纤维化成纤维细胞对凋亡的抗性的发展有助于进行性纤维化的发生， 纤维化疾病此外，我们认为抗凋亡基因Bcl-2的表达在细胞凋亡中起着重要作用， 介导促纤维化成纤维细胞的持久性。基于对二氧化硅诱导的 肺纤维化模型，我们提出测试这个中心假设有3个具体目标：具体目标1 将测试促纤维化肺成纤维细胞的体内消融将诱导持续性纤维化的消退的假设 肺内滴注二氧化硅颗粒引起的肺纤维化。具体目标2将测试 假设降低促纤维化成纤维细胞对凋亡的抗性促进了 进行性肺纤维化这一假设将使用遗传方法进行测试，以确定是否 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凋亡 肺成纤维细胞和二氧化硅诱导的肺纤维化模型中持续性纤维化的消退。 具体目标3将检验以下假设：临床相关Bcl-2抑制剂将在治疗上靶向促凋亡蛋白。 纤维化成纤维细胞和促进建立的肺纤维化的解决。这一假设将得到检验 通过用小分子抑制剂治疗小鼠以降低Bcl-2活性，阻止成纤维细胞存活并促进 体内持续性纤维化的消退。将使用微CT成像对小鼠进行随访以监测疾病 发展、进步和解决。拟议的研究将提供新的认识， 靶向促纤维化成纤维细胞的死亡，以及这如何有助于纤维化的解决。而且 这项工作的结果应该会大大影响我们对控制机制的理解。 纤维化的消退及其在其他器官和组织中的持续存在。

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.