Interleukin-37 attenuates aortic valve lesions by inhibiting N6-methyladenosine-mediated interleukin-1 receptor-associated kinase M degradation

Abstract

Aims: Calcific aortic valve disease (CAVD) has become an increasingly important global medical problem without effective pharmacological intervention. Accumulating evidence indicates that aortic valve calcification is driven by inflammation. Interleukin-1 receptor-associated kinase M (IRAK-M) is a well-known negative regulator of inflammation, but its role in CAVD remains unclear.

Methods and results: Here, we stimulated aortic valve interstitial cells (AVICs) with low-dose lipopolysaccharide (LPS) to mimic the inflammatory response in aortic valve calcification and observed the expression pattern of IRAK-M. Furthermore, we generated IRAK-M-/- mice to explore the effect of IRAK-M deficiency on the aortic valve in vivo. Additionally, overexpression and knockdown experiments were performed to verify the role of IRAK-M in AVICs. Methylated RNA immunoprecipitation-quantitative polymerase chain reaction was used to detect the N6-methyladenosine (m6A) level of IRAK-M, and recombinant interleukin (IL)-37-treated AVICs were used to determine the regulatory relationship between IL-37 and IRAK-M. We found that IRAK-M expression was upregulated in the early stages of inflammation as part of a negative feedback mechanism to modulate the immune response. However, persistent inflammation increased overall m6A levels, ultimately leading to reduced IRAK-M expression. In vivo, IRAK-M-/- mice exhibited a propensity for aortic valve thickening and calcification. Overexpression and knockdown experiments showed that IRAK-M inhibited inflammation and osteogenic responses in AVICs. In addition, IL-37 restored IRAK-M expression by inhibiting m6A-mediated IRAK-M degradation to suppress inflammation and aortic valve calcification.

Conclusion: Our findings confirm that inflammation and epigenetic modifications synergistically regulate IRAK-M expression. Moreover, IRAK-M represents a potential target for mitigating aortic valve calcification. Meanwhile, IL-37 exhibited inhibitory effects on CAVD development both in vivo and in vitro, giving us hope that CAVD can be treated with drugs rather than surgery.

Keywords: N 6-methyladenosine; Calcific aortic valve disease; Inflammation; Interleukin-1 receptor-associated kinase M; Interleukin-37.