MicroRNA-125a Correlates with Decreased Psoriasis Severity and Inflammation and Represses Keratinocyte Proliferation

Psoriasis has a complex etiology related to inflammation and dysregulated immune system. MicroRNA (miR)-125a is a miRNA intimately related to inflammation and immunity; therefore, we presumed that it might play a role in the pathogenesis of psoriasis. This study aimed to investigate the correlation of miR-125a with disease severity and inflammation in psoriasis patients, and the effect of miR-125a on proliferation, apoptosis as well as its target signaling pathway in keratinocytes.Sixty psoriasis patients were consecutively recruited, then lesional and non-lesional skin tissue samples were collected. miR-125a in lesional and non-lesional skin tissues, tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-17 mRNA expressions in lesional skin tissues were detected. Then, miR-125a overexpression, control overexpression, miR-125a knockdown and control knockdown plasmids were transfected into HaCaT cells. Subsequently, cell proliferation, apoptosis, IL-23R, JAK2, and STAT3 expressions were assessed.miR-125a was reduced in lesional skin tissue compared with non-lesional skin tissue (p < 0.001), and it distinguished lesional skin tissue from non-lesional skin tissue with a high area under curve of 0.917 (95% CI 0.866-0.968). Negative association of miR-125a in lesional skin tissue with lesional body surface area (p = 0.037) and psoriasis area and severity index score (p < 0.001) was found. Additionally, miR-125a was negatively correlated with TNF-α (p = 0.001), IL-1β (p = 0.014), and IL-17 (p = 0.003) in lesional skin tissue. In cellular experiments, miR-125a overexpression inhibited proliferation and promoted apoptosis, while miR-125a knockdown enhanced proliferation and repressed apoptosis in HaCaT cells. Additionally, miR-125a negatively regulated the IL-23R/JAK2/STAT3 pathway in HaCaT cells.miR-125a could facilitate the disease monitoring and probably has the potential to be a therapeutic target in psoriasis.