Control of fibrosing lung disease by p53-miR-34a-targeted therapeutics

特发性肺纤维化(IPF)是最常见的间质性肺部疾病，具有致命性。它影响到500,000 美国和欧洲每年确诊后中位生存期为2-3年的患者。其发病机制 人们对此知之甚少，也没有治愈的方法。IPF的一个特点是形成成纤维细胞灶，包括 大量纤维化肺成纤维细胞(FLF)和间质纤维化伴结构扭曲。这个 特发性肺纤维化患者肺组织中的fLf包括肌成纤维细胞和活化的高增殖细胞， 迁移成纤维细胞，沉积过多的基质蛋白。我们的初步数据表明， P53和microRNA-34a(miR-34a)的表达显著降低，而血小板的表达 IPF肺成纤维细胞中生长因子-(PDGFR-)的表达显著高于对照组 提取自组织学上“正常”的肺(NLF)。在博莱霉素(BLM)诱导的小鼠中也会发生这种情况 肺纤维化(PF)。此外，P53和miR-34a通过一个自动调节前馈环路发挥作用，该环路 进而抑制PDGFR-。我们的工作假设是，p53和miR-34a在fFL中减少，这 在fFL中诱导促纤维化反应，这在PF的发病机制中起关键作用。我们推断，恢复 FLFS中的P53和miR-34a可减轻PF。我们的目标是阐明P53降低的机制 而miR-34a在fFL中的表达促进了PF。我们还将确定靶向这一途径是否会抑制 FFL的促纤维化特性，从而逆转已建立的PF。多肽CSP7(FTTFTVT)将是 用于靶向这条通路。我们先前已经表明，以CSP7为靶点的P53阻断了肺泡 促进上皮细胞的凋亡，防止博莱曼诱导的肺纤维化的发生。然而，CSP7对fFL的影响是 尚不清楚，在这些细胞中靶向p53/miR-34a通路如何解决已建立的PF。这些 在我们对PF发病机制的理解上存在潜在的关键差距，将在本文中解决 项目。我们的目的是：1)阐明p53在fLFS促纤维化反应中的作用。我们将定义 P53调节FFL促纤维化反应的机制及检测CSP7阻断这些反应的能力 特发性肺纤维化患者和博莱姆或转化生长因子-诱导的肺纤维化小鼠的fFL的反应。2)确定如何 MIR-34a调节FFL中P53介导的促纤维化反应。我们将定义改变的miR-34a的作用 并检测相同的干预措施是否逆转了miR- 34a介导的反应。3)阐明P53和miR-34a介导的信号转导机制 LFS促纤维化反应的调节。最先进的建模、生化、分子和成像技术- 将使用基于基础的方法来实现这些目标。该项目将在以下方面对外地产生重大影响 首次确定P53和miR-34a如何调节促纤维化反应，包括 FFL和PF中的PDGFR-。这项工作还可能定义新的、针对p53/miR-34a的方法来逆转这些 对IPF患者的疗效和改善预后。

Idiopathic pulmonary fibrosis (IPF) is the most common interstitial lung disease and is fatal. It affects 500,000 people in the USA and Europe per year with a median survival of <2-3 years after diagnosis. Its pathogenesis is poorly understood and there is no cure. A hallmark of IPF is the formation of fibroblastic foci, consisting of large numbers of fibrotic lung fibroblasts (fLFs) and interstitial fibrosis with architectural distortion. The population of fLFs in the lungs of patients with IPF includes myofibroblasts and activated highly proliferative, migratory fibroblasts that deposit excessive matrix proteins. Our preliminary data demonstrate that basal expression of p53 and microRNA-34a (miR-34a), are markedly reduced, while expression of platelet derived growth factor- (PDGFR- is significantly increased in fLFs from IPF lungs compared with control fibroblasts extracted from histologically “normal” lungs (nLFs). This also occurs in mice with bleomycin (BLM)-induced pulmonary fibrosis (PF). In addition, p53 and miR-34a act through an autoregulatory feed-forward loop, which in turn suppresses PDGFR-. Our working hypothesis is that p53 and miR-34a are reduced in fLFs, which induce pro-fibrogenic responses in fLFs that are critical to the pathogenesis of PF. We infer that restoration of p53 and miR-34a in fLFs will mitigate PF. Our objective is to elucidate the mechanism by which reduced p53 and miR-34a expression in fLFs promote PF. We will also determine if targeting of this pathway suppresses pro-fibrogenic properties of fLFs and thereby reverses established PF. The peptide CSP7 (FTTFTVT) will be used to target this pathway. We have previously shown that the p53-targeting with CSP7 blocks alveolar epithelial apoptosis and prevents development of BLM-induced PF. However, the effects of CSP7 on fLFs are unknown, as is how targeting of the p53/miR-34a pathway in these cells resolves established PF. These represent potentially critical gaps in our understanding of the pathogenesis of PF and will be addressed in this project. Our Aims are: 1) To elucidate the role of p53 in pro-fibrogenic responses in fLFs. We will define mechanism by which p53 regulates pro-fibrogenic responses of fLFs and test the ability CSP7 to block these responses in fLFs from patients with IPF and from mice with BLM- or TGF--induced PF. 2) To determine how miR-34a regulates p53-mediated pro-fibrogenic responses in fLFs. We will define the role of altered miR-34a expression in the control of these responses in fLFs and test whether the same interventions reverse the miR- 34a-mediated responses. 3) To elucidate the signaling mechanisms involved in p53- and miR-34a-mediated regulation of pro-fibrogenic responses in LFs. State of the art modeling, biochemical, molecular and imaging- based approaches will be used to accomplish the aims. This project will have a major impact on the field by determining, for the first time, how p53 and miR-34a regulate pro-fibrotic responses including changes in PDGFR- in fLFs and PF. The work may also define novel, p53/miR-34a-targeted approaches to reverse these effects and improve outcomes for patients with IPF.