Consistent with our previous observation of the protective actions of miR-29 in liver fibrosis [3,4], miR-29 also acts as a potent fibrosis-inhibitory regulator that alleviates TGF-β1/Smad3-mediated renal fibrosis [21] and pulmonary fibrosis [22]. The gene discussed is SMAD3; the disease is renal fibrosis.