microRNA-126 expression and its mechanism of action in patients with systemic lupus erythematosus

OBJECTIVE: The aim of the present study is to investigate the expression level of microRNA-126 (miRNA-126) in the plasma of patients with systemic lupus erythematosus (SLE). PATIENTS AND METHODS: Thirty SLE patients admitted at our institution were recruited in study group and 30 normal subjects seeking health check-up at our institution during the same period were included in control group. Plasma levels of miRNA-126 were determined using fluorescent quantitative RT-PCR. Plasma levels of IFN-alpha were determined and compared between two groups using ELISA. RT-PCR was performed to measure the levels of ISG56 mRNA, an IFN-inducible gene (IFNG), in the peripheral blood mononuclear cells (PBMC) of both groups. miRNA-126 expression was interfered in PBMC of SLE patients by introducing the mimic and inhibitor of miRNA-126. Levels of ISG56 mRNA in transfected PBMCs were determined using RT-PCR. RESULTS: Levels of miRNA-126 were significantly lower in the plasma of SLE patients than normal controls (p < 0.05). Plasma levels of IFN-a were significantly higher in SLE patients than normal population (p < 0.05). ISG56 mRNA in PBMC was significantly higher in SLE patients than controls (p < 0.05). As for SLE patients, levels of IFN-alpha and ISG56 mRNA were significantly decreased in PBMCs with high expression of miRNA-126 but were significantly increased in PBMCs with low expression of miRNA-126 (p < 0.05). CONCLUSIONS: miRNA-126 expression is reduced in SLE patients. miRNA-126 may be involved in the initiation and development of SLE by inhibiting the production of IFN.