Aims:

Vascular restenosis is a common complication following vascular interventions, driven by abnormal proliferation and phenotypic switching of vascular smooth muscle cells (VSMCs). Ferroptosis, an iron-dependent regulated cell death, has been implicated in VSMC dysfunction and vascular remodeling. However, the epitranscriptomic regulation of ferroptosis in VSMCs remains unclear.

This study investigates the role of Wilms tumor suppressor gene WT1-associated protein (WTAP), a key N6-methyladenosine (m6A) RNA methylation regulator, in controlling ferroptosis of VSMCs during vascular restenosis.

Results:

A balloon injury rat model and platelet-derived growth factor-BB-stimulated VSMCs were used to mimic vascular restenosis. WTAP expression and global m6A levels were assessed. Functional assays evaluated the effects of WTAP overexpression on ferroptosis markers, reactive oxygen species (ROS), lipid peroxidation, and VSMC proliferation. Mechanistic studies explored WTAP-mediated m6A modification of the long non-coding RNA growth arrest specific 5 (GAS5), its interaction with enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2), and downstream regulation of interferon regulatory factor 4 (IRF4) and ferritin heavy chain 1 (FTH1).

WTAP expression and global m6A levels were significantly reduced in restenotic tissues and cells. WTAP overexpression restored m6A modification on GAS5, enhancing its stability via YTH domain family member 1. GAS5 inhibited EZH2-mediated H3K27me3 repression of IRF4, which transcriptionally activated FTH1, suppressing ferroptosis. WTAP overexpression decreased ROS, lipid peroxidation, and VSMC proliferation, while knockdown of GAS5 or IRF4 partially reversed these effects.

Innovation:

Our study is the first to identify that the WTAP/GAS5/IRF4 axis suppresses PDGF-BB-induced cell proliferation by inhibiting ferroptosis in VSMCs, and alleviates vascular restenosis caused by balloon injury.

Conclusion:

WTAP epitranscriptomically regulates VSMC ferroptosis via the GAS5/EZH2/IRF4/FTH1 axis, revealing a novel mechanism in vascular restenosis pathogenesis and a potential therapeutic target. Antioxid. Redox Signal. 44, 726–747.