The main data in the present study expounded that re-expression of miR-205-5p, a downregulated miRNA in AF, could alleviate the fibrosis of atrial muscle cells and mouse atrial fibrosis, whose effect was potentially achieved through impairing EHMT2-dependent H3 histone methylation of IGFBP3. The gene discussed is EHMT2; the disease is atrial fibrillation.