Identification and validation of mir-222-3p and mir-409-3p as plasma biomarkers in gestational diabetes mellitus sharing validated target genes involved in metabolic homeostasis

Gestational diabetes mellitus (GDM) causes both maternal and fetal adverse outcomes. Thederegulation of microRNAs (miRNAs) in GDM suggests their involvement in GDM pathogenesis andcomplications. Exosomes are extracellular vesicles (EVs) of endosomal origin, released via exocytosisinto the extracellular compartment. Through EVs, miRNAs are delivered in distant target cells andare able to affect gene expression. In this study, miRNA expression was analyzed to find new miRNAsthat could improve GDM classification and molecular characterization. MiRNA were profiled intotal plasma and EVs in GDM patients and normal glucose tolerance (NGT) women. Samples werecollected at third trimester of gestation from two diabetes centers. MiRNA expression was profiledin a discovery cohort using the multiplexed NanoString nCounter Human v3 miRNA. Validationanalysis was performed in a second independent cohort using RT-qPCR. A set of miRNAs resultedto be differentially expressed (DE) in total plasma and EVs in GDM. Among them, total plasmamiR-222-3p and miR-409-3p were validated in the independent cohort. MiR-222-3p levels correlatedwith fasting plasma glucose (FPG) (p < 0.001) and birth weight (p = 0.012), whereas miR-409-3pexpression correlated with FPG (p < 0.001) and inversely with gestational age (p = 0.001). The majorvalidated target genes of the deregulated miRNAs were consistently linked to type 2 diabetes andGDM pathophysiology. MiR-222-3p and miR-409-3p are two circulating biomarkers that couldimprove GDM classification power and act in the context of the molecular events leading to themetabolic alterations observed in GDM.