基于表达谱数据解析lncRNA TP53TG1调控肺泡上皮细胞衰老参与肺纤维化的作用及机制

Alveolar epithelial cell injury is the initiating factor of idiopathic pulmonary fibrosis (IPF). Cellular senescence caused by mitochondrial dysfunction is involved in epithelial cell damage and the pathological process of IPF. However, the upstream regulator and mechanism of mitochondrial dysfunction and epithelial cell senescence is poorly understood. In the previous studies, we found that lncRNA TP53TG1 was down-regulated in the lungs of IPF patients by analyzing of multiple sets of GEO (Gene Expression Omnibus) profile data. Overexpression of TP53TG1 inhibited PAK1 expression and alleviated mitochondrial injury and senescence of alveolar epithelial cells. Further study indicates that YAP1/TEAD promoted the expression of TP53TG1 and protected injured alveolar epithelial cells. Thus, we hypothesize that YAP1/TEAD↓-TP53TG1↓-PAK1↑ axis results in mitochondrial dysfunction, promotes senescence of alveolar epithelial cells, and induces pulmonary fibrosis. Based on these results, we will perform the following experiments: (1) to examine the effects of TP53TG1 on mitochondrial dysfunction and senescence of alveolar epithelial cells; (2) to reveal the molecular mechanism and functional fragment of TP53TG1 played on mitochondrial homeostasis; (3) to investigate the potential transcriptional regulation of YAP1/TEAD on TP53TG1 and the roles of YAP1/TEAD on senescence of alveolar epithelial cells; (4) to examine the potential therapeutic effect of TP53TG1 on lung fibrosis; (5) construction of an epigenetic database of organ fibrosis. This project can not only expand the understanding of the pathophysiological mechanism of IPF, but also provide a theoretical basis and novel idea for the therapeutic strategy and development of new drug for pulmonary fibrosis.

肺泡上皮细胞损伤是特发性肺纤维化（IPF）的始动因素。线粒体功能障碍诱发细胞衰老参与上皮损伤及IPF病理进程，但上游调控机制尚待阐明。前期整合多套表达谱数据发现lncRNA TP53TG1在IPF患者中表达降低；TP53TG1与PAK1蛋白结合并抑制其表达，减轻线粒体损伤及上皮细胞衰老；YAP1/TEAD促进TP53TG1表达，保护受损上皮细胞。假设：YAP1/TEAD↓-TP53TG1↓-PAK1↑导致线粒体功能障碍，促进上皮细胞衰老，诱发肺纤维化。拟研究：1）TP53TG1对线粒体功能及肺泡上皮细胞衰老的调控作用；2）TP53TG1调控线粒体稳态的分子机制及功能片段；3）YAP1/TEAD转录调控TP53TG1及其对细胞衰老的作用；4）TP53TG1对肺纤维化的治疗作用；5）建立器官纤维化表观遗传调控数据库。本项目将深化对衰老诱发IPF病理机制的认识，为IPF药物研发及防治提供新思路。

特发性肺纤维化（IPF）致死率高，预后差，尚无理想的治疗手段。近年来，空气污染、雾霾天气及新冠肺炎的爆发，我国肺纤维化发病率逐年上升。抗纤维化药物吡非尼酮和尼达尼布虽可降低患者死亡率，但有一定的局限性，肺移植是唯一有效的治疗方法。因此，阐明肺纤维化发病机制，寻找新的药物作用靶点和治疗策略迫在眉睫。肺泡上皮细胞的衰老是诱发肌成纤维细胞病灶和肺纤维化的主要因素。本项目已获得研究成果：1、探索YAP1对肺上皮细胞衰老及肺纤维化的调控作用，并揭示其分子机制。YAP1/TEAD1- Prdx3轴抑制线粒体功能障碍，减缓细胞衰老并抑制SASP分泌，减轻肺纤维化。该研究明确靶向Hippo/YAP1通路对肺纤维化的治疗潜力，为肺纤维化的理论研究和转化应用提供科学依据；2、建立器官纤维化数据库FDRdb，通过RNA表达谱进行差异表达和功能及通路富集分析，构建以RNA为核心的纤维化疾病相关平台，为纤维化相关疾病的研究提供有效工具；3、筛选调控IPF的关键lncRNA TP53TG1，明确其通过调控成纤维细胞参与肺纤维化进程；构建lncRNAs-mRNAs-IPF动态进展调控网络，发现lncRNA CTD-2528L19.6通过调控LRRC8C抑制成纤维细胞的活化进而阻止IPF进展。该研究揭示以非编码RNA为中心的IPF调控网络，评价非编码RNA对肺纤维化的调控作用4、评价干预差异表达的LncRNA PFI通过结合并抑制RNA结合蛋白SRSF1，减少EDA+Fn1剪接异构体的形成，减轻肺纤维化； LncDACH1的保守性功能片段调控SRSF1/β-catenin轴抑制成纤维细胞活化参与肺纤维化。该系列研究明确ncRNAs可作为肺纤维化治疗的干预靶点及核酸药物的临床转化新手段，为解析器官纤维化的关键调控分子和寻找安全有效的药物新靶点开创了新的研究方式和策略，为抗纤维化药物研发提供了新途径。