MiR-330-3p contributes to INS-1 cell dysfunction by targeting glucokinase in gestational diabetes mellitus.

Aims: High-expressed miR-330-3p in gestational diabetes mellitus (GDM) patients was reported. However, the role and mechanism of miR-330-3p in GDM are rarely reported. In this research, we aim to investigate the effects of miR-330-3p on GDM.

Methods: MiR-330-3p expression in the GDM patients' blood was determined by q-PCR. Blood glucose of blood samples was detected using blood glucose detection kits. Glucokinase (GCK) was confirmed to be a target gene of miR-330-3p by bioinformatics and luciferase analysis. Correlations between miR-330-3p with GCK and blood glucose were analyzed by Pearson correlation analysis. After INS-1 cells were treated with glucose and transfected with mimic, inhibitor or siGCK, GCK expression was detected by western blot, and q-PCR, enzyme-linked immunosorbent assays, cell counting kit-8 and Annexin-V/propidium iodide were conducted to examine the expression of insulin, cell viability and apoptosis.

Results: MiR-330-3p was high-expressed in GDM patients' blood, while GCK was low-expressed. The miR-330-3p expression level positively correlated with blood glucoseand and it was highly expressed in glucose-treated INS-1 cells (11 and 22 mmol/L), while miR-330-3p expression negatively correlated with GCK expression. GCK expression was inhibited by miR-330-3p mimic and enhanced by the miR-330-3p inhibitor. MiR-330-3p mimic inhibited INS-1 cells' insulin expression, cell viability and induced apoptosis. Yet miR-330-3p inhibitor and siGCK exhibited opposite effects which miR-330-3p mimic and GCK played on INS-1 cells. In addition, siGCK reversed the effect of miR-330-3p inhibitor on INS-1 cells.

Conclusion: Our findings proved that miR-330-3p targeting GCK lead to the dysfunction of INS-1 cells in GDM, and could become a therapeutic target for GDM treatment.