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微小RNA(microRNA,miRNA)作为一种基因表达调控因子,在自身免疫性疾病中起重要作用。本研究旨在研究系统性红斑狼疮(SLE)患者中低表达的miR-125a基因在SLE炎症反应中的作用及其可能的作用机制。通过miRNA Taqman荧光定量聚合酶链反应(RT-PCR),发现同正常对照组相比,miR-125a表达水平在SLE患者中明显降低。生物信息学分析发现T淋巴细胞激活晚期促进RANTES分泌的主要转录因子KLF13是miR-125a的潜在靶基因。定量结果也表明,SLE患者中KLF13和RANTES水平正相关。从基因组DNA中克隆pri-miR-125a基因,构建miR-125a的表达载体。在HeLa细胞中过表达miR-125a能抑制内源性KLF13 mRNA的表达,反之亦然。报告基因系统实验证实,miR-125a能直接作用于KLF13的3′UTR区,从而调节KLF13的表达。进一步发现过表达miR-125a可以降低狼疮T细胞分泌RANTES的水平。我们的研究表明,miR-125a通过调节转录因子KLF13的表达而调节参与狼疮发病的炎性趋化因子RANTES的分泌。这提示定向干预miR-125a的表达水平可调节炎症性趋化因子RANTES的表达,从而发展为SLE新的治疗手段。
MicroRNAs (miRNAs), as a regulator of gene expression, play an important role in autoimmune diseases. The purpose of this study was to investigate the role of miR-125a, a low-expressed miR-125a gene, in the inflammatory response of SLE in patients with systemic lupus erythematosus (SLE) and its possible mechanism. By miRNA Taqman fluorescent quantitative polymerase chain reaction (RT-PCR), miR-125a expression levels were significantly lower in patients with SLE compared with the normal control group. Bioinformatics analysis found that T lymphocyte activation late promotes the secretion of RANTES, a major transcription factor KLF13, as a potential target gene of miR-125a. Quantitative results also show that patients with SLE KLF13 and RANTES level is positively correlated. The pri-miR-125a gene was cloned from genomic DNA to construct miR-125a expression vector. Overexpression of miR-125a in HeLa cells inhibits the expression of endogenous KLF13 mRNA and vice versa. Reporter gene system experiments confirmed that, miR-125a can act directly on KLF13 3’UTR region, thereby regulating KLF13 expression. It was further found that overexpression of miR-125a can reduce the level of RANTES secreted by lupus T cells. Our study shows that miR-125a regulates the secretion of inflammatory chemokine RANTES, which is involved in the pathogenesis of lupus, by regulating the expression of the transcription factor KLF13. This suggests that directional intervention miR-125a expression levels can regulate the expression of inflammatory chemokine RANTES, and thus develop a new treatment for SLE.