Regulatory role of APA in pulmonary fibrosis during aging

项目摘要/摘要 特发性肺纤维化(IPF)是一种与年龄相关的致死性疾病，其特征是慢性、进行性和 不可逆转的纤维化。细胞衰老与特发性肺纤维化的发病机制密切相关。然而， 在IPF中促进衰老的机制，特别是在转录后水平上的机制，目前尚不清楚。这个 目前的提案将通过阐明替代多聚腺苷酸化(APA)在 衰老成纤维细胞及其在肺纤维化中的作用。 Nudex水解酶21(Nudt21，又称CFIm25)是一种RNA结合蛋白，在细胞周期中起重要作用。 APA。我们最近发现NDUT21在衰老和纤维化的肺中下调，在衰老中也是如此 成纤维细胞。正常肺成纤维细胞中Nudt21基因敲除诱导STAT3磷酸化及蛋白表达 许多衰老相关的分泌表型(SASP)因子。重要的是，成纤维细胞Nudt21耗尽 加重博莱霉素诱导的小鼠肺纤维化，而NUDT21挽救导致减轻纤维化 和SASP版本。这些发现强调了NUDT21下调是衰老的一个新的可修改因素- 为研究NUDT21介导的APA在肺纤维化中的作用奠定了坚实的基础。 衰老。基于这些广泛的初步发现，我们假设miRNA介导的NUDT21 衰老成纤维细胞的下调通过APA促进衰老过程中的肺纤维化 STAT3信号的调节和SASP的诱导。我们将在以下具体目标上检验这一假说：1)。 评估NUDT21在年龄相关性肺纤维化中作为重要介质的作用；2)确定 老化过程中NUDT21耗尽的上游机制；3)确定靶向NUDT21下游的作用 肺纤维化的成分；4)人类miRNA/NUDT21/STAT3轴的分子研究 IPF肺。这些拟议的研究具有重要意义，因为它们将阐明一种新的增强 SASP蛋白在衰老成纤维细胞中的表达可能参与IPF的发病机制。 创新包括证明miRNA/NUDT21/STAT3/SASP轴是衰老和衰老之间的新联系 IPF的发病机制，以及新的试剂和方法，包括Nudt21基因敲除小鼠，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性肺功能研究。最终，结果 这些研究将有助于开发新的治疗策略来对抗这种与年龄相关的破坏性疾病 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.