#5503 PIOGLITAZONE REVERSES MIR-130A AND MIR-199 DYSREGULATION INDUCED BY TGF-BETA DURING KIDNEY FIBROSIS

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Abstract Background and Aims The peroxisome proliferator-activated receptor-γ (PPARγ) agonists have been shown to dampen TGF-β signaling and suppress miR-130a in VSMCs and also profibrotic miR-21-5p in the kidney. We have recently demonstrated that pioglitazone ameliorates established renal fibrosis by suppressing STAT3 and EGR1 [1], but its effect on renal miR-130a has not been investigated. Thus, we aimed to study how chronic oral pioglitazone treatment would affect TGF-β–driven renal miRNA dysregulation in mice. Method Ten week old male C57Bl6 control (CTL, n = 6) and TGF-β transgenic mice (TGFb, n = 12, having elevated plasma TGF-β1 level) were used. CTL mice and half of TGFb mice received regular chow. The second half of transgenic mice received pioglitazone containing chow (dose: 20mg/kg/day) for 5 weeks (TGFb+Pio, n = 6), when the kidneys were evaluated. Results Untreated TGFb mice had a 4.7-fold and 2.8-fold type I and type III collagen mRNA overexpression as compared to controls, respectively. This was accompanied by 3.8-fold pro-fibrotic Egr2 mRNA, 2.9-fold miR-130a, 3.9-fold miR-199 and 3.3-fold miR-21 overexpression. Chronic treatment with the PPARγ agonist pioglitazone reduced the expression of both collagen mRNAs and miRNAs miR-199 and miR-21 to control levels, but miR-130a reached even lower values than in control kidneys. Interestingly, the expression of miR-200a (regulated by TGF-beta and known to ameliorate fibrosis) was similar in all CTL and TGFb groups, regardless of treatment. Conclusion Our data indicate that PPARγ agonist pioglitazone not only attenuates the TGF-β induced miR-21 overexpression, but also the renal dysregulation of miR-130a and miR-199, supporting its anti-fibrotic effects.

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