Oral Presentation International Association of the Diabetes and Pregnancy Study Groups 2022 - Hosted by ADIPS

Selective placental and adipose tissue miRNA sorting in extracellular vesicles in  gestational diabetes mellitus (#14)

Soumyalekshmi Nair 1 , Dominic Guanzon 1 , Nanthini Jayabalan 1 , Andrew Lai 1 , Katherin Scholz 1 , Flavio Carrion 2 , Martha Lappas 3 , Carlos Salomon 1 2
  1. Centre for Clinical Diagnostics, University of Queensland Centre for Clinical Research, The University of Queensland, Brisbane, QLD 4029, Australia
  2. Departamento de Investigación, Postgrado y Educación Continua (DIPEC), Facultad de Ciencias de la Salud, Universidad del Alba, Santiago, Chile
  3. Obstetrics, Nutrition and Endocrinology group, Department of Obstetrics and Gynecology, University of Melbourne, Victoria, Australia

Background: Small extracellular vesicles (sEVs) play key roles in regulating maternal metabolism by transfer of molecular signals (miRNAs) mediating cell communication between placenta and metabolic tissues (for example adipose tissue). The aim of this study is to identify the mechanism of miRNA sorting in placenta and adipose tissue sEVs and its effect on insulin sensitivity in normal glucose tolerant (NGT) and GDM pregnancies

Method: Placenta and adipose tissue were obtained from NGT (n=5) and GDM (n=5) subjects at the time of delivery. Primary human trophoblast cell cultures and adipose tissue explant cultures were developed and sEVs were isolated from their cell-conditioned media. The miRNA profile in trophoblast cells and sEVs were analyzed using next generation sequencing. Using motif analysis tool, MDS2, the overexpressed motifs (4-6 base pairs long nucleotide sequences) in the sEV enriched miRNAs were identified. The role of RNA binding proteins in the selective packaging of miRNAs in sEVs were investigated using miRNA pull down assay and siRNA mediated knock down of candidate proteins.

Results: GDM is associated with changes in miRNA expression in placental and adipose tissue sEVs. A specific set of miRNAs were highly enriched in sEVs compared to their cells of origin in NGT and GDM, in placenta and adipose tissue. The abundance of these miRNAs in sEVs compared to their cell of origin highlight the specific nature of miRNA secretion and suggest specific packaging of these miRNAs into sEVs. Further, we identified a specific set of sEV-enriched miRNAs that were unique to placenta and adipose tissue and unique to NGT and GDM condition. We classified these miRNAs into four groups based on their unique expression as (1) Placenta NGT miRNAs, (2) Placenta GDM miRNAs, (3) Adipose tissue NGT miRNAs, and (4) Adipose tissue GDM miRNAs. We identified specific motifs in each group ([CG][AU][CG]CU, [UG]GG[AC][CUG], AGU[AG][AU], [CU]UAGAG) and candidate miRNAs expressing the specific motif were chosen (hsa-miR-151a-3p, hsa-miR-28-3p, hsa-miR-222-3p, hsa-miR-432-5p, hsa-miR-199b-5p, hsa-miR-548g-5p hsa-miR-182-5p, hsa-miR-517a-3p). Further, we identified that RNA binding proteins YBX3, GRSF1, HNRNPH2, FASTKD2, HDLBP, DISC3 and CW19L1 were associated with selective packaging of these miRNAs.

Conclusion: These findings provide insights into the mechanisms by which miRNA-protein interactions lead to selective packaging of miRNAs into sEVs in healthy pregnancy and GDM, and will further elucidate the potential of these mechanism as novel therapeutic platform in GDM

Funding: National Health and Medical Research Council (NHMRC, 1114013)