Elevated circulating LncRNA NORAD fosters endothelial cell growth and averts ferroptosis by modulating the miR-106a/CCND1 axis in CAD patients

Atherosclerosis is a leading cause of cardiovascular diseases, characterized by endothelial dysfunction and lipid accumulation. Long non-coding RNAs (lncRNAs) are emerging as key regulators of endothelial cell behavior. This study aimed to investigate the role of lncRNA NORAD in endothelial cell proliferation and as a potential therapeutic target for atherosclerosis. A total of 75 CAD patients and 76 controls were recruited, and plasma NORAD levels were measured using qRT-PCR. HUVECs were transfected with si-NORAD to evaluate its effects on cell cycle, proliferation, migration, and apoptosis. Plasma NORAD levels were significantly elevated in CAD patients. The NORAD-miRNA-mRNA ceRNA regulatory network was constructed based on GEO database, and G1/S-specific cyclin-D1 (CCND1) was identified as one of the hub factors. NORAD deficiency suppressed cell migration and induced G1 cell cycle arrest in HUVECs by downregulating CCND1 in vitro. NORAD upregulated CCND1 in HUVECs via sponging miR-106a that inhibited cell migration. The dual-luciferase assay confirmed the direct targeting of miR-106a by NORAD, and overexpression of miR-106a inhibited HUVEC proliferation and migration. Si-NORAD transfection resulted in induced early apoptosis, increased intracellular ROS levels, decreased GSH levels, and reduced mitochondrial membrane potential. Additionally, si-NORAD decreased the expression of GPX4, FTH1, KEAP1, NCOA4, and Nrf2, while increasing Xct levels, confirming the involvement of ferroptosis. Our findings reveal that NORAD plays a critical role in endothelial cell proliferation, migration, and apoptosis, and its silencing induces ferroptosis. The regulatory network involving NORAD, miR-106a, and their target genes provides a potential therapeutic avenue for atherosclerosis.