Dysregulated miRNAs contribute to altered placental glucose metabolism in patients with gestational diabetes via targeting GLUT1 and HK2

Abstract

Introduction: Dysregulated genes in glucose transport and metabolize pathways have been found in patients with Gestational diabetes (GDM), but the underlying mechanisms were still unclear.

Materials and methods: Placental villous samples were collected from 31 patients with GDM and 20 healthy controls. The expression of GLUT1, GLUT4, GLUT9 and HK2 was examined by immunoblotting and qRT-PCR. The miRNAs have the potential targeting GLUT1 and HK2 were predicted using online bioinformatics tool: TargetScan. The interaction between miRNAs and target genes were confirmed by dual luciferase assay and immunoblotting. The function of miR-9 and miR-22 on glucose metabolism was examined by glucose uptake assay and lactate secretion assay.

Results: GLUT1 and HK2 proteins level was found upregulated in patients with GDM, but the mRNA level was not significantly changed. Predicted by using bioinformatics tools and confirmed by dual luciferase assay and immunoblotting, GLUT1 was identified as a target of miR-9 and miR-22, whereas HK2 was identified as a target of miR-9. MiR-9 and miR-22 level was found reduced in the placenta villous and negatively correlated with the expression of GLUT1 and HK2. Functional studies indicated that miR-9 and miR-22 inhibitors upregulated the expression of GLUT1 and HK2, and then increased the glucose uptake, lactate secretion, cell viability and repressed apoptosis in primary syncytiotrophoblasts (STBs) and HTR8/SVneo cells.

Discussion: The upregulation of GLUT1 and HK2 in the placenta, which is induced by miR-9 and miR-22 reduction, contributes to the disordered glucose metabolism in patients with GDM.

Keywords: GLUT1; Gestational diabetes; HK2; microRNA.