Anti-fibrotic effects of the Mirlet7/NuRD ribonucleoprotein complexin idiopathic pulmonary fibrosis

Mirlet7/NuRD 核糖核蛋白复合物在特发性肺纤维化中的抗纤维化作用

• 批准号: 408916879
• 负责人: Professor Dr. Guillermo Barreto, Ph.D.
• 金额: --
• 依托单位: IMoPA Ingénierie Moléculaire et Physiopathologie Articulaire
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/408916879?language=en
• 关键词: Anti; fibrotic; effects; Mirlet7; NuRD

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive and highly lethal interstitial lung disease with unknown etiology and with poor prognosis. IPF patients die within 2 to 5 years after diagnosis mostly due to respiratory failure. Lung tissues from IPF patients show fibroblastic foci that consist of expanded myofibroblast population and excessive extracellular matrix (ECM) protein deposition. Myofibroblasts are contractile activated fibroblasts that express α-smooth muscle actin (ACTA2) to facilitate wound closure after injury. However, persistent activation of these cells causes excessive deposition of ECM in the interstitial space that leads to fibrosis. The precise control of gene expression is essential for both expansions of activated fibroblasts after injury and dedifferentiation into resting fibroblasts after wound healing. During dedifferentiation of activated fibroblast into resting fibroblast, the balance between transcription of lineage specific genes and repression of pro-fibrotic genes allows resolution of fibrotic foci. The regulation of gene expression is intimately linked to chromatin structure. The nucleosome remodeling and deacetylase (NuRD) complex is one of the main regulators for chromatin structure. NuRD has been implicated in a wide variety of nuclear processes including gene transcription, DNA damage repair, maintenance of genome stability and chromatin assembly. On the other hand, previous reports suggest that noncoding RNAs (ncRNAs) are required either for modulating the activity of chromatin regulators or for recruiting them to specific gene loci. Interestingly, even though ncRNAs has been related to IPF, their function at molecular level in IPF has remained elusive. Here, we will investigate the function of micro RNAs (miRNAs) in the nucleus, focusing on the miRNA lethal 7 (Mirlet7, also known as let-7) due to its implication in lung diseases. The present project proposal aims to characterize Mirlet7d-mediated recruitment of NuRD complex to specific loci and fine tuning of its activity during dedifferentiation of activated fibroblasts into resting cells within the context of IPF. We will use as experimental system human primary fibroblasts isolated from donor and IPF patients. Our findings will provide the molecular mechanism as basis for the development of therapeutic approaches against IPF. Furthermore, the therapeutic potential of Mirlet7d against IPF will be confirmed using the bleomycin animal model, the most commonly used model of pulmonary fibrosis. We expect that Mirlet7d administration will attenuate the fibrotic effects induced by bleomycin, thereby confirming our in vitro data and supporting the development of therapeutic strategies against IPF using Mirlet7d.

特发性肺纤维化(IPF)是一种病因不明、预后不良的慢性进行性高致死性间质性肺疾病。IPF患者在确诊后2至5年内死亡，主要死于呼吸衰竭。IPF患者的肺组织显示成纤维细胞灶，包括扩张的肌成纤维细胞群和过度的细胞外基质(ECM)蛋白沉积。肌成纤维细胞是一种收缩激活的成纤维细胞，表达α-平滑肌肌动蛋白(ACTA2)以促进创伤后伤口的愈合。然而，这些细胞的持续激活会导致ECM在间质中过度沉积，从而导致纤维化。基因表达的精确控制对于创伤后激活的成纤维细胞的扩张和伤口愈合后去分化为静止的成纤维细胞都是至关重要的。在活化的成纤维细胞去分化为静止的成纤维细胞的过程中，谱系特异性基因的转录和促纤维化基因的抑制之间的平衡使得纤维化灶得以解决。基因表达的调控与染色质结构密切相关。核小体重构与脱乙酰酶复合体(NuRD)是染色质结构的主要调节因子之一。NuRD参与了广泛的核过程，包括基因转录、DNA损伤修复、维持基因组稳定性和染色质组装。另一方面，以前的报道表明，非编码RNA(NcRNAs)是调节染色质调节剂活性或将其招募到特定基因位点所必需的。有趣的是，尽管ncRNAs与IPF相关，但它们在IPF分子水平上的功能仍然难以捉摸。在这里，我们将研究微RNA(MiRNAs)在细胞核中的功能，重点放在miRNA致死7(Mirlet7，也被称为let-7)上，因为它与肺部疾病有关。本项目提案旨在表征Mirlet7d介导的NuRD复合体在特定位点的募集，以及在IPF背景下激活的成纤维细胞脱分化为静息细胞过程中其活性的微调。我们将使用从供者和IPF患者身上分离的人原代成纤维细胞作为实验系统。我们的发现将为IPF治疗方法的发展提供分子机制的基础。此外，Mirlet7d对IPF的治疗潜力将通过博莱霉素动物模型得到证实，博莱霉素动物模型是最常用的肺纤维化模型。我们预计Mirlet7d给药将减轻博莱霉素诱导的纤维化效应，从而证实我们的体外数据，并支持利用Mirlet7d开发针对IPF的治疗策略。