MiR-126 correlates with increased disease severity and promotes keratinocytes proliferation and inflammation while suppresses cells' apoptosis in psoriasis

Background Methods This study aimed to investigate the miR-126 expression in lesional skin and its correlation with clinical features in psoriasis patients and to explore the effect of upregulated miR-126 on cells' proliferation, apoptosis, and inflammation in human keratinocytes. A total of 102 psoriasis patients were consecutively enrolled in this study. MiR-126 expressions in lesional skin and paired nonlesional skin were detected by quantitative polymerase chain reaction (qPCR). Human keratinocytes (HaCaT cells) were transfected with miR-126 mimic plasmids and blank mimic plasmid. Cell Counting Kit-8 and annexin V/propidium iodide assays were performed to assess the cells' proliferation and apoptosis, and protein levels of apoptotic markers (cleaved caspase-3 [C-caspase-3] and B-cell lymphoma-2 [Bcl-2]) were detected by Western blot assay. Inflammatory cytokines mRNA and protein levels were detected by qPCR and Western blot assays, respectively. Results Conclusion MiR-126 expression was upregulated in lesional skin tissue compared with paired nonlesional skin tissue, and its expression positively associated with Psoriasis Area and Severity Index score in psoriasis patients. MiR-126 expression was increased in miR-126 mimic group compared with negative control (NC) mimic group after plasmids transfection into HaCaT cells, and cells' proliferation was enhanced while cells' apoptosis rate was reduced in miR-126 mimic group than NC mimic group. Protein expressions of C-caspase and Bcl-2 also indicated miR-126 mimic decreased the cells' apoptosis. In addition, miR-126 mimic increased TNF-alpha, IFN-gamma, IL-17A, and IL-22 expressions while decreased IL-10 expression. In conclusion, miR-126 correlates with elevated risk and increased disease severity in psoriasis patients, and upregulation of miR-126 promotes cells' proliferation and inflammation while inhibits cells' apoptosis in keratinocytes.