Theranostics 2020; 10(20):8939-8956. doi:10.7150/thno.45178

Research Paper

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

Dongdong Jian1*, Ying Wang1*, Liguo Jian2*, Hao Tang3, Lixin Rao1, Ke Chen1, Zhen Jia4, Wanjun Zhang5, Yiran Liu6, Xu Chen7, Xiwen Shen7, Chuanyu Gao1✉, Shuai Wang8✉, Muwei Li1✉

1. Department of Cardiology, Henan Provincial People's Hospital, Department of Cardiology of Central China Fuwai Hospital, Henan Key Laboratory for Coronary Heart Disease Prevention and Control, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, Henan, 450003, China.
2. Department of Cardiology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450003, China.
3. Heart Center of Henan Provincial People's Hospital, Central China Fuwai Hospital, Key Laboratory for Cardiac Regenerative Medicine, National Health Commission & Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, Henan, 450003, China.
4. Department of Cardio-Thoracic Surgery, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310003, China.
5. Department of Hematology, Henan Provincial People's Hospital, Zhengzhou, Henan, 450003, China.
6. Department of Pathology, Henan Provincial People's Hospital, Zhengzhou, Henan, 450003, China.
7. Department of Hepatobiliary and Pancreatic Surgery, Zhengzhou People's Hospital, Zhengzhou, Henan, 450003, China.
8. School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China.
*These authors contributed equally to this work.

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Citation:
Jian D, Wang Y, Jian L, Tang H, Rao L, Chen K, Jia Z, Zhang W, Liu Y, Chen X, Shen X, Gao C, Wang S, Li M. METTL14 aggravates endothelial inflammation and atherosclerosis by increasing FOXO1 N6-methyladeosine modifications. Theranostics 2020; 10(20):8939-8956. doi:10.7150/thno.45178. Available from https://www.thno.org/v10p8939.htm

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Abstract

Aims: The N6-methyladenosine (m6A) 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 m6A 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 m6A modification-related proteins to identify the major factors involved in this process. The m6A-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 m6A-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, m6A 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 m6A 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 m6A 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.

Keywords: METTL14, m6A modification, endothelial inflammation, FOXO1, atherosclerosis