MiR-193b inhibits autophagy and apoptosis by targeting IGFBP5 in high glucose-induced trophoblasts

Introduction: Inhibiting Apoptosis of trophoblasts in women with gestational diabetes mellitus (GDM) is expected to guarantee adequate nutrition for the fetus and avoid abortion. MiR-193b is one of the most downregulated miRNAs in GDM patients. However, less is known about the role of miR-193b in Autophagy and Apoptosis in GDM patients.

Methods: We detected the expression of miR-193b in GDM patients. Then, we cultured human trophoblasts (HTR8 cells) with high glucose (HG) to simulate a diabetic environment in vitro, and further explored the effects of miR-193b on Apoptosis and Autophagy of HG-treated HTR8 cells.

Results: The expression of miR-193b was significantly downregulated in the peripheral blood of GDM patients compared with healthy controls, and decreased miR-193b caused apparent Autophagy and a substantially high Apoptosis rate in HG-treated HTR8 cells. These effects were reversed by enhancing miR-193b expression or using the Autophagy Inhibitor 3-MA. Inhibiting miR-193b induced the pro-autophagic, cytostatic, and pro-apoptotic effects reduced by 3-MA in HTR8 cells upon HG treatment. Moreover, the expression of insulin-like growth factor-binding protein 5 (IGFBP5) was upregulated notably in the peripheral blood of GDM patients, and IGFBP5 appears to represent a direct miR-193b target. Note that silencing IGFBP5 blocked Autophagy and Apoptosis in HG-treated HTR8 cells, an effect that was diminished by inhibiting miR-193b.

Conclusion: Our data indicate that aberrantly low expression of miR-193b in HG-induced trophoblasts results in massive Apoptosis events by upregulating IGFBP5-induced Autophagy, which may trigger GDM. Therefore, miR-193b may became a potential target for GDM therapy.