In an AF model based on nicotine administration and rapid pacing, the two interventions induced atrial fibrosis via TGF-β1 and TGF-β receptor type-2 (TGFBR2), in parallel with a significant reduction in the expressions of miR-133 and miR-590, which target TGF-β1 and TGFBR2 (Shan et al., 2009). Here, TGFBR2 is linked to atrial fibrillation.