METTL14 aggravates endothelial inflammation and atherosclerosis by increasing FOXO1 N6-methyladeosine modifications

Abstract

Aims: The N6-methyladenosine (m ⁶A) modification plays an important role in various biological processes, but its role in atherosclerosis remains unknown. The aim of this study was to investigate the role and mechanism of m ⁶A modification in endothelial cell inflammation and its influence on atherosclerosis development.

Methods: We constructed a stable TNF-α-induced endothelial cell inflammation model and assessed the changes in the expression of m ⁶A modification-related proteins to identify the major factors involved in this process. The m ⁶A-modified mRNAs were identified by methylated RNA immunoprecipitation (RIP) sequencing and forkhead box O1 (FOXO1) was selected as a potential target. Through cytological experiments, we verified whether methyltransferase-like 14 (METTL14) regulates FOXO1 expression by regulating m ⁶A-dependent mRNA and protein interaction. The effect of METTL14 on atherosclerosis development in vivo was verified using METTL14 knockout mice.

Results: These findings confirmed that METTL14 plays major roles in TNF-α-induced endothelial cell inflammation. During endothelial inflammation, m ⁶A modification of FOXO1, an important transcription factor, was remarkably increased. Moreover, METTL14 knockdown significantly decreased TNF-α-induced FOXO1 expression. RIP assay confirmed that METTL14 directly binds to FOXO1 mRNA, increases its m ⁶A modification, and enhances its translation through subsequent YTH N6-methyladenosine RNA binding protein 1 recognition. Furthermore, METTL14 was shown to interact with FOXO1 and act directly on the promoter regions of VCAM-1 and ICAM-1 to promote their transcription, thus mediating endothelial cell inflammatory response. In vivo experiments showed that METTL14 gene knockout significantly reduced the development of atherosclerotic plaques.

Conclusion: METTL14 promotes FOXO1 expression by enhancing its m ⁶A modification and inducing endothelial cell inflammatory response as well as atherosclerotic plaque formation. Decreased expression of METTL14 can inhibit endothelial inflammation and atherosclerosis development. Therefore, METTL14 may serve as a potential target for the clinical treatment of atherosclerosis.