ALYREF inhibits ferroptosis in vascular endothelial cells and improves atherosclerosis by epigenetic modification of CISD1.

Abstract

Background: Atherosclerosis (AS) is a disease marked by lipid metabolism dysfunction. Methylation of 5-methylcytosine (m⁵C) mRNA can regulate AS progression. We investigated the role and mechanism of m⁵C reader ALYREF in AS.

Methods: ApoE^-/- mice AS models were constructed. Oil Red O staining evaluated the degree of aortic plaque. Serum LDL and TG levels were assessed. ELISA detected vascular inflammation and ATP production. Expressions of ALYREF, CISD1, and ferroptosis-related proteins were detected by RT-qPCR and Western blot. CCK-8, EdU, and flow cytometry were used to detect cell viability and apoptosis. RIP assay validated the direct binding of ALYREF to CISD1. Mitochondrial morphology was observed by transmission electron microscopy (TEM). Mitochondrial membrane potential was determined by JC-1. Mitochondrial ROS and cytoplasmic ROS were tested by immunofluorescence staining. Oxidative stress damage (MDA), antioxidant enzymes (SOD/GSH), and Fe²⁺ levels were detected by kits. Methylated RNA was immunoprecipitated with m⁵C-specific antibody (MeRIP).

Results: ALYREF expression declined in AS mice and human primary coronary artery endothelial cells (HCAEC) induced by oxidized low-density lipoprotein (ox-LDL). Elevated ALYREF improved ox-LDL-induced HCAEC apoptosis, inflammation, and lipid metabolism. ALYREF elevation attenuated mitochondrial damage and ferroptosis in ox-LDL-exposed HCAEC. ALYREF facilitated the stability and expression of CISD1 mRNA through m⁵C methylation. Reversing CISD1 expression negated the protective effects of ALYREF overexpression against ox-LDL-induced HCAEC damage. ALYREF-mediated epigenetic modification of CISD1 alleviated AS progression by reducing lipid levels and inhibiting ferroptosis in vivo.

Conclusion: By enhancing m⁵C modification, ALYREF enhances the stability and expression of CISD1 mRNA, which impedes lipid metabolism and endothelial cell ferroptosis in AS and alleviates AS-associated pathological changes.