Regulatory role of APA in pulmonary fibrosis during aging

项目总结/摘要 特发性肺纤维化（IPF）是一种致命的年龄相关性疾病，其特征在于慢性、进行性和全身性肺纤维化。 不可逆纤维化细胞衰老广泛涉及IPF的发病机制。但 促进IPF衰老的机制，特别是在转录后水平，知之甚少。的 目前的提案将通过阐明替代性多聚腺苷酸化（阿帕）在 衰老成纤维细胞及其在肺纤维化中的作用 Nutrient Hydrolase 21（Nudt 21，也称为CFIm 25）是一种RNA结合蛋白，在细胞凋亡中起重要作用。 阿帕。我们最近发现，NDUT 21在衰老和纤维化的肺以及衰老的肺组织中下调。 成纤维细胞正常肺成纤维细胞中的Nudt 21敲低诱导STAT 3磷酸化和STAT 3的表达 许多衰老相关分泌表型（SASP）因子。重要的是，成纤维细胞Nudt 21缺失 加重博莱霉素诱导的小鼠肺纤维化，而NUDT 21拯救导致减弱的纤维化 SASP释放这些发现强调NUDT 21下调是一种新的可改变的衰老因素。 与IPF相关，并为研究NUDT 21介导的APA在肺纤维化中的作用提供了坚实的基础。 衰老基于这些广泛的初步发现，我们假设miRNA介导的NUDT 21 衰老成纤维细胞的下调通过阿帕促进衰老过程中的肺纤维化 STAT 3信号转导和SASP诱导的调节。我们将在以下具体目标中检验这一假设：1）。 评估NUDT 21作为年龄相关性肺纤维化的重要介质的作用; 2）确定NUDT 21在年龄相关性肺纤维化中的作用。 3）定义靶向NUDT 21下游的作用 肺纤维化中的miRNA/NUDT 21/STAT 3轴的分子研究 IPF肺。这些拟议的研究是有意义的，因为它们将阐明一种新的机制， SASP蛋白在衰老成纤维细胞中的表达可能有助于IPF的发病机制。 创新包括证明miRNA/NUDT 21/STAT 3/SASP轴是衰老和衰老之间的新联系。 IPF发病机制，以及新的试剂和方法，包括Nudt 21敲除小鼠，原代肺和 来自老年/IPF受试者的成纤维细胞，以及动物模型中的创新肺功能研究。最终，结果 这些研究将有助于开发新的治疗策略，以对抗这种破坏性的年龄相关疾病。 疾病

PROJECT SUMMARY/ABSTRACT Idiopathic Pulmonary Fibrosis (IPF) is a lethal age-related disease characterized by chronic, progressive, and irreversible fibrosis. Cellular senescence has been widely implicated in the pathogenesis of IPF. However, the mechanism promoting senescence in IPF, especially at the post-transcriptional level, is poorly understood. The current proposal will address this knowledge gap by elucidating the role of alternative polyadenylation (APA) in senescent fibroblasts and its contribution to pulmonary fibrosis. Nudix Hydrolase 21 (Nudt21, also known as CFIm25) is an RNA binding protein playing an important role in APA. We recently found that NDUT21 is downregulated in aging and fibrotic lungs as well as in senescent fibroblasts. Nudt21 knockdown in normal lung fibroblasts induces STAT3 phosphorylation and the expression of many senescence-associated secretory phenotype (SASP) factors. Importantly, fibroblast Nudt21 depletion aggravated bleomycin-induced pulmonary fibrosis in mice, whereas NUDT21 rescue led to attenuated fibrosis and SASP release. These findings highlight NUDT21 downregulation as a novel modifiable factor for aging- related IPF and provide a strong foundation to study the role of NUDT21-mediated-APA in lung fibrosis during aging. Based on these extensive preliminary findings, we hypothesize that miRNA-mediated NUDT21 downregulation in senescent fibroblasts promotes pulmonary fibrosis during aging, through APA regulation of STAT3 signaling and SASP induction. We will test this hypothesis in following specific aims: 1). Evaluate the role of NUDT21 as an important mediator in age-associated lung fibrosis; 2) Determine the upstream mechanism for NUDT21 depletion during aging; 3) Define the role of targeting NUDT21 downstream components in pulmonary fibrosis; and 4) Molecular investigation of the miRNA/NUDT21/STAT3 axis in human IPF lungs. These proposed studies are significant because they will elucidate a novel mechanism for enhanced expression of SASP proteins in senescent fibroblasts that could contribute to the pathogenesis of IPF. Innovations include demonstrating the miRNA/NUDT21/STAT3/SASP axis as a novel link between aging and IPF pathogenesis, and new reagents and methodologies including Nudt21 knockout mice, primary lungs and fibroblasts from aged/IPF subjects, and innovative lung functional studies in animal models. Ultimately, results from these studies will facilitate development of novel therapeutic strategies against this devastating age-related disease.