1. Academic Validation
  2. METTL3 mediates Ang-II-induced cardiac hypertrophy through accelerating pri-miR-221/222 maturation in an m6A-dependent manner

METTL3 mediates Ang-II-induced cardiac hypertrophy through accelerating pri-miR-221/222 maturation in an m6A-dependent manner

  • Cell Mol Biol Lett. 2022 Jul 14;27(1):55. doi: 10.1186/s11658-022-00349-1.
Rui Zhang 1 Yangyang Qu 1 Zhenjun Ji 1 Chunshu Hao 1 Yamin Su 1 Yuyu Yao 1 Wenjie Zuo 1 Xi Chen 1 Mingming Yang 1 Genshan Ma 2
Affiliations

Affiliations

  • 1 Department of Cardiology, Zhongda Hospital, School of Medicine, Southeast University, 87 Hunan road, Nanjing, 210000, Jiangsu, People's Republic of China.
  • 2 Department of Cardiology, Zhongda Hospital, School of Medicine, Southeast University, 87 Hunan road, Nanjing, 210000, Jiangsu, People's Republic of China. magenshan@hotmail.com.
Abstract

Background: METTL3 is the core catalytic Enzyme in m6A and is involved in a variety of cardiovascular diseases. However, whether and how METTL3 plays a role during angiotensin II (Ang-II)-induced myocardial hypertrophy is still unknown.

Methods: Neonatal rat cardiomyocytes (NRCMs) and C57BL/6J mice were treated with Ang-II to induce myocardial hypertrophy. qRT-PCR and western blots were used to detect the expression of RNAs and proteins. Gene function was verified by knockdown and/or overexpression, respectively. Luciferase and RNA immunoprecipitation (RIP) assays were used to verify interactions among multiple genes. Wheat germ agglutinin (WGA), hematoxylin and eosin (H&E), and immunofluorescence were used to examine myocardial size. m6A methylation was detected by a colorimetric kit.

Results: METTL3 and miR-221/222 expression and m6A levels were significantly increased in response to Ang-II stimulation. Knockdown of METTL3 or miR-221/222 could completely abolish the ability of NRCMs to undergo hypertrophy. The expression of miR-221/222 was positively regulated by METTL3, and the levels of pri-miR-221/222 that bind to DGCR8 or form m6A methylation were promoted by METTL3 in NRCMs. The effect of METTL3 knockdown on hypertrophy was antagonized by miR-221/222 overexpression. Mechanically, Wnt/β-catenin signaling was activated during hypertrophy and restrained by METTL3 or miR-221/222 inhibition. The Wnt/β-catenin antagonist DKK2 was directly targeted by miR-221/222, and the effect of miR-221/222 inhibitor on Wnt/β-catenin was abolished after inhibition of DKK2. Finally, AAV9-mediated cardiac METTL3 knockdown was able to attenuate Ang-II-induced cardiac hypertrophy in mouse model.

Conclusions: Our findings suggest that METTL3 positively modulates the pri-miR221/222 maturation process in an m6A-dependent manner and subsequently activates Wnt/β-catenin signaling by inhibiting DKK2, thus promoting Ang-II-induced cardiac hypertrophy. AAV9-mediated cardiac METTL3 knockdown could be a therapeutic for pathological myocardial hypertrophy.

Keywords

Angiotensin II; Cardiac hypertrophy; METTL3; Wnt/β-catenin signaling; miR-221/222.

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