MiR-34a及其靶基因参与皮肌炎肺间质病变发病机制的研究

Dermatomyositis (DM) is an inflammatory autoimmmune disease with skin and muscle involvement. Intestinal lung disease (ILD) is a predictor of poor prognosis in DM. Novel diagnostic tools and therapeutic targets are critically required. MicroRNAs (miRNAs) dysregulation can result in many autuimmune diseases, and its expression profiling and functional study have become useful tools in demonstrating intracellular molecular regulation, while few studies on DM-ILD related miRNA was reported in China and abroad. Our previous work has confirmed that peripheral blood mononuclear cells (PBMC) of DM had a specific expression pattern of miRNAs and upregulation of miR-34a may be involved in the pathogenesis of DM-ILD, but the exact mechanism is still unkown. Based on this, our study aims to explore further on the relation of miR-34a and DM-ILD through a large-sample clinical registry and biobank. And in the cellular and molecular level, the target genes of miR-34a will be screened and validated. Through the study of the mechanism of miR-34a, target gene and TGF-β induced lung fibroblast, the possible mechanism of miR-34a involved in the pathogenesis of DM-ILD was explored. These results will contribute to understanding the pathogenesis of DM, developing new biological markers, and making the foundation for the development of new therapeutic targets.

皮肌炎是一种以皮肤、肌肉受累为主的炎症性自身免疫病，肺间质病变（ILD）是其预后不良的重要因素，亟需提高诊断水平并探索新的治疗靶点。小分子RNA（miRNA）调控异常可引起多种自身免疫病，其表达谱和功能研究已成为揭示细胞内分子调控机制的有力工具，而DM-ILD相关miRNA研究在国内外鲜有报道。本课题的前期研究发现miR-34a在DM中特异性高表达，并与DM-ILD相关。本课题拟在此基础上，通过大样本临床与标本库进一步验证miR-34a与DM的肺部病变的相关性。并在细胞和分子生物学层面，筛选miR-34a对应的靶基因，进行功能研究和验证。通过miR-34a、靶基因和转化生长因子-β（TGF-β）诱导肺成纤维细胞的作用机制研究，探索miR-34a参与DM-ILD发病的可能机制。这些结果将有助于深入了解DM-ILD的发病机制，开发新型生物学标记物，为发展新的治疗靶点奠定基础。

皮肌炎是一种以皮肤、肌肉受累为主的炎症性自身免疫病，肺间质病变（ILD）是其预后不良的重要因素，亟需提高诊断水平并探索新的治疗靶点。小分子RNA（miRNA）调控异常可引起多种自身免疫病，其表达谱和功能研究已成为揭示细胞内分子调控机制的有力工具，而DM-ILD相关miRNA研究在国内外鲜有报道。本课题的前期研究发现miR-34a在DM中特异性高表达，并与DM-ILD相关。本课题拟在此基础上，通过大样本临床与标本库进一步验证miR-34a与DM的肺部病变的相关性。并在细胞和分子生物学层面，筛选miR-34a对应的靶基因，进行功能研究和验证。通过miR-34a、靶基因和转化生长因子-β（TGF-β）诱导肺成纤维细胞的作用机制研究，探索miR-34a参与DM-ILD发病的可能机制。在本研究中，我们构建了TGF-β1诱导的肺纤维化BEAS-2B细胞模型，并通过qRT-PCR和western blot检测肺纤维化标志物的表达水平对模型进行鉴定，发现α-SMA, N-cadherin, vimentin, collagen I的表达水平在TGF-β1加入后显著升高。利用miR-34a模拟物或抑制剂处理TGF-β1诱导的BEAS-2B细胞，发现miR-34a模拟物的加入可以抑制肺纤维化进程，同时发现miR-34a能抑制sirt1表达并降低mTOR的活性。进一步研究发现mTOR激活剂3BDO能逆转miR-34a模拟物对肺纤维化蛋白表达的抑制作用，表明miR-34a 可能通过介导mTOR调控肺纤维化。通过注射博来霉素诱导小鼠肺纤维化构建体内模型，结果表明小鼠肺组织出现严重的纤维化。将miR-34a和mTOR作为干预的靶点对炎症反应介导的肺纤维化具有治疗作用，而其中的具体分子机制仍需要进一步的探索研究。