MiRNA-122-5p mimic significantly strengthened the expression of Wnt1 and β-catenin and the expression of target genes c-Jun, c-Myc, and Cyclin D1, which could be reversed by Smad5 overexpression, suggesting that miRNA-122-5p/Smad5 axis maybe induce PF through regulating the Wnt/β-catenin signaling pathway. The gene discussed is JUN; the disease is pemphigus foliaceus.