O-GlcNAc Modification Orchestrates HUWE1-Mediated Ubiquitination of TfR1 to Regulate Ferroptosis and Trophoblast Syncytialization in Preeclampsia.

Trophoblast stress may be one of the etiologies of the pathology of the placenta in preeclampsia (PE). During pregnancy, females experience a substantial increase in iron requirements. Paradoxically, excessive iron intake or elevated iron levels can pose risks to pregnancy and contribute to reproductive disorders. Labile iron, owing to its oxidative and toxic properties, triggers cellular oxidative stress and initiates ferroptosis. O-GlcNAc modification has been linked to ferroptosis in recent studies. However, its involvement in the pathophysiology of PE remains elusive. Our research identified abnormal ferroptosis in preeclamptic placentas, and was accompanied by reduced O-GlcNAc modification levels. Increasing O-GlcNAc modification rescued trophoblast syncytialization defects and oxidative stress damage induced by iron overload or ferroptosis. Through O-GlcNAc modification proteomics, we screened and validated the E3 ubiquitin ligase HUWE1 as a pivotal factor in trophoblast ferroptosis and syncytialization. Mechanistically, O-GlcNAc modification stabilizes HUWE1, facilitating the ubiquitination-mediated degradation of its substrate, transferrin receptor1 (TfR1). This process reduces iron uptake by trophoblasts, thereby inhibiting ferroptosis during syncytialization. Moreover, elevated O-GlcNAcylation ameliorates iron overload-induced preeclamptic phenotypes and mitigates adverse pregnancy outcomes. These findings highlight the unique role of O-GlcNAcylated HUWE1 in regulating TfR1 ubiquitination and suggest that targeting this pathway may offer a novel therapeutic strategy for PE.