Extracellular vesicle-associated miR-515-5p from adipose tissue regulates placental metabolism and fetal growth in gestational diabetes mellitus.

Background: Gestational diabetes mellitus (GDM) affects 2-20% of pregnant women worldwide and is linked to fetal overgrowth, increased perinatal morbidity, and mortality, as well as a higher risk of developing cardiovascular disease later in life for mother and child. MicroRNAs (miRNAs), which regulate gene expression, can be transported within extracellular vesicles (EVs). Adipose tissue-derived EVs have been associated with changes in placental metabolism in GDM, potentially influencing cardiovascular health outcomes. This study aimed to evaluate the miRNA profile in EVs from omental adipose tissue in GDM and their effect on placental nutrient uptake and fetal growth.

Methods: This case-control study included patients with normal glucose tolerance (NGT) and GDM. We conducted a miRNA expression profiling on omental adipose tissue and its derived EVs from women with NGT (n = 20) and GDM (n = 36). Trophoblast cells were utilized to assess the effect of EVs on glucose and fatty acid uptake, pro-inflammatory cytokine, and chemokine release. Double-stranded miRNA mimics were used to investigate the effect of selected miRNAs on trophoblast cells. Subsequently, the impact of EVs from NGT and GDM, as well as miR-515-5p, on in vivo glucose tolerance and fetal growth was assessed in pregnant mice.

Results: Fifty-four miRNAs showed significant differences between EVs from the adipose tissue of NGT and GDM groups. EVs from GDM increased glucose uptake in trophoblast cells, whereas EVs from NGT increased the secretion of CXCL8, IL-6, CXCL1, CXCL4, and CXCL5 from trophoblasts compared to the effect without EVs. Specifically, miR-515-5p increased glucose uptake and abolished TNF-α-dependent increase in pro-inflammatory cytokines and chemokines from trophoblast cells. Injection of pregnant mice with EVs from NGT adipose tissue loaded with miR-515-5p resulted in increased fetal weight and glucose levels.

Conclusion: miR-515-5p, specifically encapsulated within EVs from omental adipose tissue in GDM, regulates placental nutrient uptake, glucose homeostasis, and fetal growth.