Circulating miRNA - 130b - 3p promotes epithelial - to - mesenchymal transition in renal tubular epithelial cells by inhibiting expression of ERBB2IP and PPAR.GAMMA.

Objective To investigate a possible molecular mechanism of MiRNA-130b-3p involved in renal damage. Methods Human renal tubular epithelial cells(HK-2) were transfected with MiR-130b-3p mimics or normal control mimics. Then HK-2 cells were stimulated with 10 μg/L recombinant TGF-β1 for 72 h. After 72 h, the mRNA and protein expression of Collegen Ⅳ, α-smooth muscle actin(α-SMA), Collegen Ⅰ and E-cadherin were quantified by real-time PCR and Western blotting. The mRNA and protein expression of ERBB2IP and PPARγ were also detected. The reporter plasmids containing ERBB2IP 3'-UTR and PPARγ 3'-UTR were constructed. The activity of ERBB2IP and PPARγ were detected by dual luciferase report system. Results Compared to NC mimic group, transfection of HK-2 cells with MiR-130b-3p mimics resulted in significantly increased expression of mRNA and protein of Collegen Ⅳ, α-SMA, Collegen Ⅰ, and decreased expression of E-cadherin after stimulating by TGF-β1(all P <0.05). And MiR-130b-3p mimic could significantly down-regulate the mRNA and protein expression of ERBB2IP and PPARγ in HK-2 cells(all P<0.05) whether in the presence of TGF-β1 or not. The dual luciferase reporter assay showed that MiR-130b-3p induced decreased ERBB2IP 3'-UTR luciferase activity compared to NC mimic group, but there was no significant difference between NC mimic group and mut-MiR-130b-3p mimic group. MiR-130b-3p mimic+mut-PPARγ-3'UTR cotransfection group had lower PPARγ luciferase activity than NC mimic + mut-PPARγ-3'UTR group, and MiR-130b-3p+PPARγ-3'UTR group got lower further(all P <0.01). Conclusions MiR-130b-3p promotes epithelial-to-mesenchymal transition(EMT) in renal tubular epithelial cells by directly targeting at the 3'-UTR of ERBB2IP and PPARγ, which may play an important role in renal damage of early stage lupus nephritis. Key words: Lupus nephritis; MicroRNAs; Epithelial-to-mesenchymal transition; Adaptor proteins, singal transducing; PPAR gamma