Maternal obesity increases the risk of fetal and neonatal complications, placing a significant burden on health services1,2. microRNAs (miRNAs) are small, non-coding RNAs that can modify the post-transcriptional regulation of target mRNAs and, consequently, the expression of their proteins4. miRNAs are a potential source of novel biomarkers for medical complications of obesity and diabetes, including during pregnancy3,4. Placenta is a rich source of miRNAs that are detectable in maternal plasma3. The overall objective of this project is to determine starting with in vitro experiments placental-derived miRNAs that may be indicative of placental metabolic injury and predictive of adverse pregnancy outcomes in obese mothers.
Three placentas were collected from normal weight healthy women undergoing elective caesarian sections. Trophoblasts were harvested and established in primary culture with low and high glucose with and without fatty acids (FA). After 48 hours, the media was collected and used for miRNA analysis using OpenArrayTM to determine miRNAs differentially released into the media in response to nutrient-induced stress.
In discovery phase OpenArrayTM experiments, trophoblasts cultured in the nutrient-toxic condition of high glucose with FA (25mM G, 0.25mM palmitate:oleate) compared to the basal condition of low glucose without FA (5.5mM G) released 10 miRNAs into the media at quantities that were greater than 5 fold increased (2 miRNAs were >100 fold increased).
Interestingly, the majority of these miRNAs from the discovery phase analysis are involved in the regulation of genes involved in cellular stress (e.g. vascular endothelial growth factor (VEGF) and hypoxia inducible factor 1-α (HIF-1α)), cell proliferation and cell migration pathways. Further analysis will be undertaken to compare the fold changes between other experimental groups. Future studies will validate these miRNAs using qPCR in primary culture samples as well as maternal plasma collected from obese women with various pregnancy outcomes.