Pioglitazone attenuates kidney fibrosis via miR-21-5p modulation

Pioglitazone has been demonstrated to exert anti-fibrotic and renoprotective effects. But the detailed pharmacological mechanisms have not been clearly revealed. The present study aimed to investigate the possible mechanisms of pioglitazone in these two effects. TGF-β1-stimulated HK-2 cells and unilateral ureteral obstruction (UUO) mice were used as in vitro and in vivo models. The results showed that pioglitazone inhibited Smad-2/3 phosphorylation, upregulated Smad-7 expression and downregulated miR-21-5p expression in TGF-β1-exposed HK-2 cells. In addition, miR-21-5p inhibitors replicated the anti-fibrotic effects of pioglitazone, and miR-21-5p mimics inhibited these effects. In in vivo study, pioglitazone attenuated UUO-induced renal fibrosis and significantly decreased the expressions of pro-fibrotic proteins. Whereas, agomir of miR-21-5p inhibited the renoprotective function of pioglitazone in UUO mice. In conclusion, the present data suggest that modulation of miR-21-5p/Smad-7 signal may be involved in the anti-fibrotic effect of pioglitazone in the kidney of UUO mice.