The m6A methyltransferase METTL3 promotes hypoxic pulmonary arterial hypertension.

AIMS: N6-methyladenosine (m6A) is the most prevalent internal chemical RNA modification in mammal mRNAs. Accumulating evidence has shown the critical role of m6A in cardiovascular diseases including cardiac hypertrophy, heart failure, ischemic heart disease, vascular calcification, restenosis, and aortic aneurysm. However, whether m6A participates in the occurrence and development of hypoxic pulmonary hypertension (HPH) remains largely unknown. The present study aims to explore the role of key transferase METTL3, in the development of HPH.

MATERIALS AND

METHODS

Pulmonary artery smooth muscle cells (PASMCs) and hypoxic rat models were used to research the METTL3-mediated m6A in HPH. EdU, transwell and TUNEL were performed to evaluate the proliferation, migration and apoptosis rates. m6A RNA Methylation Quantification Kit and m6A-qPCR were utilized to measure the total m6A level and m6A level of PTEN mRNA. RNA immunoprecipitation was used to detect the interaction between METTL3 and PTEN mRNA.

KEY FINDINGS: Both METTL3 mRNA and protein were found abnormally upregulated in vivo and in vitro. Furthermore, downregulation of METTL3 attenuated PASMCs proliferation and migration. In addition, m6A binding protein YTHDF2 was found significantly increased in PASMCs under hypoxia. YTHDF2 recognized METTL3 mediated m6A modified PTEN mRNA and promoted the degradation of PTEN. Decreased PTEN led to over-proliferation of PASMCs through activation of PI3K/Akt signaling pathway.

SIGNIFICANCE: METTL3/YTHDF2/PTEN axis exerts a significant role in hypoxia induced PASMCs proliferation, providing a novel therapeutic target for HPH.