PGE2 regulates ferroptosis and osteogenesis of MC3T3-E1 cells via NOS2

Prostaglandin E2 (PGE2) is a key inflammatory mediator in orthodontic tooth movement, yet its precise role in regulating osteogenesis remains unclear. This study investigated the mechanism by which PGE2 influences ferroptosis and osteogenesis in MC3T3-E1 cells, focusing on nitric oxide synthase 2 (NOS2). Bioinformatic analysis identified NOS2 as a core ferroptosis-related gene after orthodontic force loading. 100 ng/mL PGE2 induced sterile inflammation and ferroptosis as evidenced by upregulated expressions of IL-6, NOS2, and ACSL4 while downregulated expressions of GPX4, FTH1 detected by RT-qPCR and western blot, alongside promoted reactive oxygen species and malondialdehyde production detected by flow cytometry. Meanwhile, PGE2 inhibited osteogenesis characterized by downregulated expressions of osteogenic markers RUNX2, Osterix, OPN, OCN and diminished ALP activity and mineralization level detected by RT-qPCR, western blot, ALP staining, ARS staining, ALP activity detection and Ca²⁺ level assessment. Effects following PGE2 treatment were rescued by the ferroptosis inhibitor Ferrostatin-1. Crucially, NOS2 knockdown mitigated PGE2-induced ferroptosis and osteogenic suppression, whereas NOS2 overexpression exacerbated them. Furthermore, NOS2 overexpression alone sufficed to promote ferroptosis and inhibit osteogenesis absent inflammation. In conclusion, PGE2 induces sterile inflammation, it also triggers ferroptosis and inhibits osteogenesis via NOS2, revealing a novel molecular axis in bone remodeling during orthodontic treatment.