Jornal da Síndrome Metabólica

Leptin Inhibits Preproinsulin mRNA Expression Induced by Suppression of Cytokine Signalling 3 in Beta-Cells

Abstract

Jiaqiang Zhou, Jiahua Wu, Fengqin Dong, Zhe Zhang, Fang Wu and Hong Li

Aim: To study the role of crosstalk between SOCS3 and leptin on insulin expression in rat insulinoma (RIN-5AH) cells that inducibly express SOCS3 mRNA.

Materials and Methods: SOCS3 and preproinsulin mRNA expression induced by 5 μM ponasterone A, and the effects of leptin on SOCS3 and preproinsulin mRNA levels were detected by RT-PCR and quantitative PCR, respectively. The effects of SOCS3 on STAT3 phosphorylation were investigated by Western blot analysis.

Results: We discovered that SOCS3 regulates preproinsulin mRNA levels in a dose-dependent and timedependent manner. The insulin-suppressing effect of leptin appears to be mediated through reducing the suppressive effects of SOCS3 on STAT3 phosphorylation.

Conclusion: Our findings suggest that leptin inhibits preproinsulin mRNA expression induced by SOCS3 in RIN-5AH beta-cells.