Histone methyltransferase G9a drives ferroptosis to aggravate vascular calcification by inhibiting SLC7A11 transcription

Abstract

Vascular calcification (VC) exacerbates the risk of cardiovascular morbidity and mortality in individuals with chronic kidney disease (CKD), and recent advances in pathogenesis have highlighted the significance of ferroptosis. The histone methyltransferase G9a participates in the regulation of different types of cell death including ferroptosis, but its role in VC needs to be further explored. Here, we found that G9a expression was elevated in microarray data obtained from CKD mouse VSMC specimens, and further experiments demonstrated similar results in CKD patients, mouse calcified arteries and rat calcified VSMCs. Functionally, G9a overexpression promoted high calcium and phosphate-induced VSMCs calcification, whereas G9a deficiency had a protective effect. Moreover, our results confirmed that G9a promoted VSMCs calcification through cystine pathway-mediated ferroptosis. Mechanistically, histone H3 lysine 9 dimethylation (H3K9me2) which was catalyzed by G9a, interacted with the promoter of solute carrier family 7 member 11 (SLC7A11) to inhibit its transcription and ferroptosis-related signaling pathways. SLC7A11, a cysteine transporter and ferroptosis suppressor, eliminated the adverse effects of G9a overexpression on ferroptosis and VC in VSMCs. Finally, in vivo overexpression of G9a aggravated VC and ferroptosis in the aorta of CKD mice, accompanied by down-regulation of SLC7A11 expression. In summary, our study reveals that the G9a/H3K9me2/SLC7A11 pathway is a new molecular mechanism for ferroptosis in VC, offering potential guidance for the development of new strategies in the treatment of VC.