Exosomal miR-152-5p promotes trophoblast apoptosis by inhibiting the PI3K/AKT/FOXO3a signaling pathway via targeting VAMP3 in gestational diabetes mellitus

Introduction: Trophoblast Apoptosis is a major cause of adverse pregnancy outcomes in patients with gestational diabetes mellitus (GDM). The aim of this study was to investigate the mechanism of action of exosomal MicroRNAs (miRNAs) retrieved from the peripheral blood of patients with GDM on trophoblast Apoptosis.

Methods: Ultracentrifugation was performed to collect peripheral blood-carrying exosomes. HTR-8/SVneo (HTR-8) cell line was used in Apoptosis assay and 293T cell line was used in dual-luciferase assay. Apoptosis was analyzed by flow cytometry, immunofluorescence (IF) and western blotting (WB). Differentially expressed miRNA was obtained through RNA Sequencing. The dual-luciferase assay was performed to verify the gene targeting. WB, qPCR, immunohistochemistry and IF were used to detect the expression of vesicle associated membrane protein 3 (VAMP3). HTR-8 cells were co-transfected with miR-152-5p inhibitor and siVAMP3 to identify the mechanism of miR-152-5p in regulating Apoptosis under high glucose conditions.

Results: miR-152-5p was significantly upregulated in exosomes from patients with GDM vs controls. In vitro miR-152-5p upregulation was associated with increased trophoblast Apoptosis. miR-152-5p downregulation was associated with activation of PI3K/Akt/FOXO3a pathway and higher levels of VAMP3. VAMP3 was a target of miR-152-5p, and its expression was lower in GDM placental tissues. The inhibition of VAMP3 expression was associated with enhanced trophoblast Apoptosis in vitro. Exosomal miR-152-5p inhibited the PI3K/Akt/FOXO3a pathway leading to decreased proliferation and increased trophoblast Apoptosis, and this was mediated by the inhibition of targeting VAMP3.

Discussion: miR-152-5p, the most differentially expressed exosomal miRNA, appeared to increase trophoblast Apoptosis by inhibiting the VAMP3 pathway.

Apoptosis; Exosome; Gestational diabetes mellitus; Placenta; VAMP3; miR-152-5p.