METTL14 Promotes Ferroptosis in Smooth Muscle Cells During Thoracic Aortic Aneurysm by Stabilizing the m6A Modification of ACSL4

Cardiovascular System Medicine Immunology Life Sciences Cell Biology
ferroptosis thoracic aortic aneurysm smooth muscle cells METTL14 ACSL4 m6A modification

Mettl14 Promotes Ferroptosis in Vascular Smooth Muscle Cells During Thoracic Aortic Aneurysm by Stabilizing the m6A Modification of ACSL4

Academic Background

Thoracic aortic aneurysm (TAA) is a severe vascular disease that often leads to aortic rupture and acute dissection, with extremely high mortality rates. Currently, the primary treatment for TAA is surgical repair, but the surgery carries significant risks, and the pathogenesis of TAA remains incompletely understood. The development of TAA is closely related to the loss of vascular smooth muscle cells (VSMCs), degradation of the extracellular matrix (ECM), and chronic inflammation. In recent years, ferroptosis, a novel form of cell death, has been found to play an important role in various diseases, but its specific regulatory mechanisms in TAA remain unclear. Therefore, this study aims to explore how Mettl14 regulates the stability of ACSL4 mRNA through m6A modification, thereby influencing ferroptosis in VSMCs and ultimately promoting the progression of TAA.

Paper Source

This paper was co-authored by Wenjun Wang, Jiayi Chen, Songqing Lai, Ruiyuan Zeng, Ming Fang, Li Wan, and Yiying Li. The authors are affiliated with the Department of Cardiovascular Surgery at the First Affiliated Hospital of Jiangxi Medical College, Nanchang University; the First Clinical Medical College of Nanchang University; the Emergency Department of the Gaoxin Branch of the First Affiliated Hospital of Jiangxi Medical College, Nanchang University; and the Prenatal Diagnosis Center of the First Affiliated Hospital of Jiangxi Medical College, Nanchang University. The paper was first published on December 14, 2024, in the journal American Journal of Physiology-Cell Physiology, with the DOI: 10.1152/ajpcell.00577.2024.

Research Process

1. Establishment of the TAA Mouse Model and Detection of Ferroptosis

The study first established a TAA mouse model by injecting angiotensin II (Ang II) and treated it with the ferroptosis inhibitor Liproxstatin-1. The experiment was divided into three groups: saline group, Ang II group, and Ang II + Liproxstatin-1 group. The maximum diameter of the thoracic aorta in mice was measured using ultrasound, and pathological damage was evaluated. The results showed that Ang II significantly increased the maximum diameter of the thoracic aorta, leading to thickening of the aortic wall, hypertrophy of the tunica media, and rupture of elastic fibers, while Liproxstatin-1 partially reversed these pathological changes.

2. Induction of Ferroptosis in VSMCs and Expression of Mettl14

The study further induced ferroptosis in human aortic smooth muscle cells (HASMCs) cultured in vitro using the ferroptosis activator Imidazole Ketone Erastin (IKE) and detected the expression of Mettl14. The results showed that IKE significantly increased the level of m6A modification and the expression of Mettl14 in HASMCs.

3. Regulation of ACSL4 mRNA Stability by Mettl14

Through bioinformatics prediction and experimental validation, the study found that ACSL4 mRNA contains an m6A modification site, and Mettl14 and IGF2BP2 directly bind to ACSL4 mRNA. Knockdown of Mettl14 or IGF2BP2 significantly reduced the stability of ACSL4 mRNA and inhibited ferroptosis.

4. Effect of Mettl14 Knockdown on TAA Progression

The study knocked down Mettl14 expression by injecting adeno-associated viruses (AAVs) and found that Mettl14 knockdown significantly reduced the increase in the maximum diameter of the thoracic aorta induced by Ang II and improved pathological damage. Additionally, Mettl14 knockdown reduced the levels of MDA and Fe2+ in thoracic aortic tissues, increased GSH levels, upregulated GPX4 and SLC7A11 expression, and downregulated ACSL4 expression.

5. Effect of ACSL4 Overexpression on Mettl14 Knockdown

Finally, the study overexpressed ACSL4 in HASMCs and found that ACSL4 overexpression partially reversed the inhibitory effect of Mettl14 knockdown on ferroptosis, further confirming that Mettl14 promotes ferroptosis by regulating ACSL4 expression.

Main Results

  1. Elevated Levels of Ferroptosis in the TAA Mouse Model: Ang II significantly increased the maximum diameter of the thoracic aorta and elevated the level of ferroptosis in VSMCs, while Liproxstatin-1 partially reversed these changes.
  2. Upregulation of Mettl14 in TAA: Mettl14 was significantly upregulated in the TAA mouse model and IKE-induced HASMCs, with increased levels of m6A modification.
  3. Mettl14 Regulates the Stability of ACSL4 mRNA: Mettl14 stabilizes ACSL4 mRNA through m6A modification, and IGF2BP2 recognizes this modification to enhance its stability, thereby promoting ferroptosis.
  4. Inhibition of TAA Progression by Mettl14 Knockdown: Knockdown of Mettl14 significantly reduced the increase in the maximum diameter of the thoracic aorta induced by Ang II, improved pathological damage, and inhibited ferroptosis.
  5. Reversal of Mettl14 Knockdown Effects by ACSL4 Overexpression: Overexpression of ACSL4 partially reversed the inhibitory effect of Mettl14 knockdown on ferroptosis, further confirming that Mettl14 promotes ferroptosis by regulating ACSL4 expression.

Conclusions and Significance

This study reveals for the first time that Mettl14 promotes ferroptosis in VSMCs during the progression of TAA by stabilizing the m6A modification of ACSL4 mRNA. This discovery not only provides a new molecular basis for understanding the pathogenesis of TAA but also offers potential therapeutic targets for developing strategies targeting ferroptosis. Inhibiting the expression of Mettl14 or ACSL4 may effectively slow the progression of TAA, providing new insights into TAA treatment.

Research Highlights

  1. Important Findings: Mettl14 promotes ferroptosis in VSMCs during TAA progression by stabilizing the m6A modification of ACSL4 mRNA.
  2. Novel Research Methods: The study combined bioinformatics prediction, RNA immunoprecipitation (RIP), and RNA pull-down experiments to systematically validate the interaction between Mettl14 and ACSL4 mRNA.
  3. Potential Application Value: Mettl14 and ACSL4 may serve as potential therapeutic targets for TAA, providing a theoretical foundation for the development of new therapeutic drugs.

Other Valuable Information

This study also provides detailed experimental data and charts supporting the reliability of the research conclusions. Additionally, the authors have made the relevant datasets publicly available for further analysis and validation by other researchers.