Decreased Expression of Circulating miR-20a-5p in South African Women with Gestational Diabetes Mellitus.

BACKGROUND AND OBJECTIVE: In recent years circulating microRNAs (miRNAs) have attracted interest as biomarkers of metabolic disease. MiRNA expression varies across population groups; thus, the aim of this study was to investigate whether serum miRNAs that have previously been shown to be associated with gestational diabetes mellitus (GDM) in other populations, are similarly regulated in South African women with GDM.

METHODS: In this case-control study, women (n = 81) were selected from a prospective cohort study in which pregnant women were recruited at their first clinic visit and requested to return for fasting blood glucose concentration measurements and serum collection (median 27 weeks; range 13-31 weeks). The expression of miR-16-5p, miR-17-5p, miR-19a-3p, miR-19b-3p, miR-20a-5p, miR-29a-3p, miR-132-3p, and miR-222-3p was quantified using miScript® (Qiagen, Hilden, Germany) miRNA PCR arrays.

RESULTS: MiR-20a-5p (2.7-fold decrease; p = 0.038) and miR-222-3p (2.6-fold decrease; p = 0.027) were significantly decreased in women with GDM compared with controls. Logistic regression showed that miR-20a-5p and one or more risk factor are significant predictors of GDM. Functional assessment using DIANA-miRPath v3.0 revealed that miR-20a-5p controls various metabolic pathways, including insulin signaling.

DISCUSSION: This study identifies miR-20a-5p as a potential biomarker for GDM in our population. Gene targets of miR-20a-5p regulate a number of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways not related to GDM, suggesting that miR-20a-5p may have limited disease specificity on its own. Such miRNAs may be useful if incorporated into miRNA panels or risk assessment algorithms to identify GDM. Studies with larger samples are required to strengthen the candidacy of miR-20a-5p as a biomarker for GDM and to assess clinical applicability.