Circular RNA HIPK3 facilitates ferroptosis in gestational diabetes mellitus by regulating glutathione peroxidase 4 DNA methylation.

Background: Gestational diabetes mellitus (GDM) is the most frequently occurring complication during pregnancy, with a high prevalence rate. Ferroptosis, a type of iron-dependent cell death, is closely associated with GDM nosogenesis. The present study aimed to examine the potential role and mechanism of circHIPK3 in GDM.

Methods: Placental tissues, plasma samples, and HTR-8/SVneo cells were used. A receiver operating characteristic curve was used to analyze the diagnostic value of circHIPK3 in GDM. Actinomycin D and RnaseR were added to identify circHIPK3 characteristics. The expression of circHIPK3, miR-1278, and DNA methyltransferase 1 (DNMT1) was assessed using a quantitative reverse transcriptase-PCR. Cell counting kit-8 and terminal deoxynucleotidyl transferase dUTP nick end labeling assays and specific kits were employed to assess cell viability, apoptosis, reactive oxygen species (ROS), malondialdehyde, iron, glutathione, and glutathione peroxidase 4 (GPX4) levels.

Results: The interaction between miR-1278 and circHIPK3 or DNMT1 was validated via luciferase reporter and RNA pull-down assays. circHIPK3 expression was found to be high in GDM placental tissues, plasma, and cells, with a high diagnostic value. In high glucose (HG)-induced HTR-8/SVneo cells, the inhibition of circHIPK3 provoked cell viability and mitigated cell apoptosis, ROS, and iron levels, but it was rescued through the downregulation of miR-1278. Mechanism experiments showed that circHIPK3 bound with miR-1278 targeting DNMT1 in GDM. The elevation in DNMT1 expression abolished the effects of miR-1278 overexpression on ferroptosis in HG-cultured HTR-8/SVneo cells.

Conclusions: Overall, circHIPK3 might facilitate ferroptosis via miR-1278/DNMT1 to regulate GPX4 DNA methylation in HG-cultured HTR-8/SVneo cells. CircHIPK3 could be a therapeutic agent for GDM treatment.