1972-P: Adipose Tissue–Derived Exosomal MicroRNA Regulates Placental Glucose Uptake in Gestational Diabetes Mellitus Pregnancies

Adipose tissue exosomal miRNAs (exomiRs) serve as a signalling molecule that is involved in conveying intercellular message signalling. In this study, we aimed to profile the adipose tissue exomiRs in patients with normal glucose tolerant (NGT) and gestational diabetes mellitus (GDM). Omentum were obtained from BMI-matched NGT (n=10) and GDM (n=10) women at delivery (>37 weeks gestation). Isolated exosomes were characterised based on size distribution and protein enrichment. Total exosomal RNA was isolated by miRNeasy (Qiagen) according to manufacturer’s instructions. Illumina TrueSeq Small RNA kit was used to construct a small RNA library. Finally, the resulting sequencing FASTQ files were analysed using miRDeep2 to identify both known and novel miRNAs. A selected exomiR mimic was overexpressed in the human primary trophoblast (PHT) cells and its effect on glucose uptake was evaluated using 2-NBDG. We identified a total of 1209 miRNAs with 18 miRNAs were significantly differentially expressed in GDM exosomes. Comparatively, 12 miRNAs were upregulated while 6 were downregulated in the exosomes from GDM pregnancy compared to normal pregnancy. Consequently, has-miR-515-5p was selected to be investigated in further functional studies, following validation of its expression using real-time PCR. The QRT-PCR analysis of placental tissue showed a significant increase in the expression of GDM placenta compared to NGT placenta. In PHT cells, the overexpression of miR-515-5p significantly stimulated the glucose uptake (p<0.0001) compared to control group. The proteomics analysis of miR-515-5p overexpressed PHT cells showed differential expression of proteins that are associated with glycolysis. These findings suggest adipose tissue exosomal miR515-5p mediated placental glucose uptake could contribute to an excessive placental nutrient transfer GDM, which could instigate consequences, such as fetal overgrowth.