# METTL3/RBM15 augments the stability of Kdm6b mRNA and promotes STAT1-mediated macrophage activation and atherosclerosis

## TL;DR

The study shows that m6A RNA modifications and the KDM6B protein play a key role in activating immune cells called macrophages, which contribute to atherosclerosis, and inhibiting KDM6B reduces inflammation and disease progression in mice.

## Contribution

The study reveals a novel regulatory mechanism involving m6A modification and KDM6B in macrophage activation and atherosclerosis progression.

## Key findings

- m6A modification modulates KDM6B expression during macrophage activation.
- KDM6B interacts with and demethylates Jak1 to induce phosphorylation-mediated macrophage activation.
- Inhibiting KDM6B reduces inflammation and slows atherosclerosis progression in mice.

## Abstract

Atherosclerosis is the underlying cause of cardiovascular disease. Recent studies have shown that N6-methyladenosine (m6A) modification in macrophages is associated with atherosclerosis progression. However, there is a lack of systemic research on the role of m6A modification in macrophage differentiation and activation during atherosclerosis. Here we conducted multiomics analysis (MeRIP-seq and RNA-seq) of macrophages during their differentiation and activation to elucidate the regulatory network of the m6A spectrum at different stages. Western blot, quantitative PCR (qPCR), RNA-seq and RNA immunoprecipitation (RIP)–qPCR results demonstrated that m6A modification modulates KDM6B expression during macrophage activation. Through co-immunoprecipitation, RIP‒qPCR and genetic perturbation experiments, we revealed that Mettl3/Rbm15 regulates the stability of Kdm6b mRNA and that Kdm6b is required for interacting with and demethylating Jak1 to induce its phosphorylation-mediated macrophage activation. Next, through the analysis of single-cell RNA-seq data and coculture experiments, we revealed that Kdm6b-mediated macrophage activation promoted cytotoxic T lymphocyte cytotoxicity following atherosclerosis progression. Moreover, the systemic use of STM2457, a METTL3 inhibitor, revealed the importance of m6A modification in immune cell infiltration and plaque activation. Finally, we utilized macrophage-specific Kdm6b-knockout mice to determine whether Kdm6b facilitates macrophage and cytotoxic T lymphocyte activation and atherosclerosis. Our findings revealed that m6A modification plays a pivotal role in the upregulation of Kdm6b in response to IFN-γ stimulation, which is essential for the phosphorylation of Stat1-induced macrophage activation-mediated atherosclerosis development.

In this study, we conduct meRIP-seq analysis on macrophages during their differentiation and activation to elucidate the landscape of the m6A spectrum across different stages. Combined analysis of RNA-seq and meRIP-seq revealed that Kdm6b interacts with and demethylates Jak1, promoting its phosphorylation-mediated activation of macrophages. Activated macrophages interact with T cells to promote atherosclerosis progression.

Atherosclerosis, a major cause of heart disease and stroke, involves inflammation and immune responses. Researchers have found that a protein called KDM6B plays a role in this process. The study explored how KDM6B affects immune cells called macrophages during atherosclerosis. Researchers used mice to study macrophages, which are immune cells that can become activated and contribute to inflammation. They focused on a chemical modification called m6A on RNA, which affects how genes are expressed. They used techniques such as meRIP-seq to analyze these modifications. They found that m6A modifications are important for macrophage activation and that KDM6B helps regulate this process. When KDM6B was inhibited, it reduced inflammation and slowed down atherosclerosis progression in mice. The study concludes that targeting KDM6B could be a potential strategy to treat atherosclerosis by reducing inflammation.

This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author.