Role of overexpression of microRNA-31 and its downstream target genes Sfn and SuFu in animal models of psoriasis
Objective:To investigate the role of intrinsic overexpression of microRNA-31(miR-31)and its downstream target genes Stratifin(Sfn)and Suppressor of Fused(SuFu)in the development and progression of psoriasis induced by imiquimod(IMQ)in a mouse model.Methods:The literature and PubMed were searched to identify the genes associated with psoriasis,and Target Scan Human database was used to predict the target genes of miR-31.IMQ cream was used to induce psoriasis in wild-type FVB mice and miR-31 transgenic mice;images of the dorsal skin were collected from these model mice daily,and the PASI score was used to evaluate the severity of psoriasis.HE staining was used to observe histomorphological changes.The dorsal skin of the mice was collected on days 0,3,and 7,and RT-PCR was used to measure the mRNA expression levels of miR-31 and its downstream target genes.Two target genes were identified and analyzed by immunofluorescence assay and Western blot.Results:The Target Scan Human database pre-dicted eight downstream target genes of miR-31,and quantitative real-time PCR obtained two target genes associated with psoriasis,i.e.,Sfn and SuFu.IMQ induced psoriasis-like symptoms in mice,including erythema,scales,and epidermal thickening of the dorsal skin.The experimental results showed that the miR-31 experimental group had milder psoriatic symptoms than the wild-type FVB ex-perimental group,which was confirmed by HE staining.RT-PCR was used to measure the expression levels of miR-31,Sfn,and SuFu on days 3 and 7,and the results showed an increase in the ex-pression of miR-31 in wild-type FVB mice and a reduction in miR-31 transgenic mice,while the expression levels of its target genes Sfn and SuFu showed opposite changes.The results of immunofluorescence assay and Western blot results were consistent with the re-sults of PCR.Conclusion:In the animal model of psoriasis,there are weak psoriatic symptoms in the skin with intrinsic overexpression of miR-31,and it may reduce the severity of psoriasis in combination with the organs associated with psoriasis in the body through the intrinsic overexpression of miR-31.Sfn and SuFu are the downstream target genes of miR-31 and may play an inhibitory role in the pathogenesis of psoriasis.