A Preliminary Study of circ‐PNPT1/miR‐144‐3p/UBE2G1 Expression in Placental Tissues and Serum and Its Mechanism in Patients With Gestational Diabetes Mellitus

Circular RNAs are associated with important pathophysiological characteristics of gestational diabetes mellitus (GDM). This study preliminarily explored circular polyribonucleotide nucleotidyltransferase 1 (circ-PNPT1) expression in placental tissues and serum of GDM patients and its role in regulating the miR-144-3p/UBE2G1 axis to affect endothelial dysfunction in GDM. Twenty GDM patients and 20 pregnant women with normal glucose tolerance were enrolled. Human umbilical vein endothelial cells (HUVECs) were cultured with high glucose (HG) to establish an in vitro GDM model, then treated with short hairpin-circ-PNPT1 and a lentiviral empty plasmid. Circ-PNPT1 levels, HUVEC viability, endothelial function, and oxidative damage were assessed using RT-qPCR tube formation, CCK-8, flow cytometry, and Transwell assays, respectively. Normally cultured and HG-cultured HUVEC samples underwent small RNA sequencing to analyze differentially expressed miRNAs. The possible miRNAs and mRNAs downstream of circ-PNPT1 were screened using bioinformatics and verified using RT-qPCR, dual luciferase reporter assay, and Ago2-RIP. GDM patients exhibited highly expressed circ-PNPT1 and UBE2G1, and weakly expressed miR-144-3p in placental tissues and serum. In vitro, HG-treated HUVECs displayed highly expressed circ-PNPT1 and cellular dysfunction, as evidenced by reduced cell survival, enhanced apoptosis, decreased cell migration and angiogenesis, an elevated MDA level, and downregulated SOD and GSH-Px levels. Circ-PNPT1 knockdown alleviated HG-induced HUVEC dysfunction. circ-PNPT1 might target and bind miR-144-3p; miR-144-3p might target and bind UBE2G1. Additionally, circ-PNPT1 might act as a competing endogenous RNA for miR-144-3p to regulate UBE2G1 expression in HG-induced HUVECs. Taken together, circ-PNPT1 modulates HG-induced HUVEC dysfunction via the miR-144-3p/UBE2G1 axis.