METTL3–m⁶A–LOXL2 Axis Post-Transcriptionally Fine-Tunes Macrophage Migration and Invasion

Abstract

Objective

While the RNA modification N⁶-methyladenosine (m⁶A) is known to influence immune cell function, its specific role in regulating macrophage migration and invasion remains poorly defined. This study aimed to elucidate the function and mechanism of the core m⁶A methyltransferase METTL3 in the migratory and invasive capacities of macrophages.

Methods

A macrophage-specific METTL3-knockdown model was established. The functional effects of METTL3 deficiency were systematically evaluated using migration, invasion, phagocytosis, and polarization assays. Subsequent transcriptome sequencing (RNA-seq) and methylated RNA immunoprecipitation-quantitative PCR (MeRIP-qPCR) were employed to identify the key differentially expressed gene, lysyl oxidase-like 2 (LOXL2). This mechanistic link was ultimately confirmed through functional rescue experiments and reconstitution assays.

Results

METTL3 deficiency significantly increased the migratory and invasive capacities of macrophages but attenuated their phagocytic activity, promoting a shift toward an M2-like polarization state. Mechanistically, METTL3 knockdown reduced m⁶A modification at a specific site of LOXL2 mRNA, thereby decreasing its RNA stability and leading to decreased expression. Importantly, this phenotype was validated through functional inhibition assays. Reconstitution of LOXL2 in METTL3-deficient macrophages substantially reversed the enhanced migratory and invasive phenotypes.

Conclusion

This study reveals a novel METTL3–m⁶A–LOXL2 signaling axis that posttranscriptionally fine-tunes macrophage migration and invasion by regulating gene expression. These findings provide a mechanistic explanation for the functional dynamics of macrophage migration and invasion and underscore that m⁶A modification is a key regulator of innate immune cell behavior.

Keywords

Macrophages / METTL3 / m⁶A methylation / LOXL2 / Cell migration

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Funding

National Natural Science Foundation of China(STS-HP-202304)

Jiangsu Provincial Department of Science and Technology(BM2022010)

Suzhou Municipal Science and Technology Bureau(SJC2022007)

RIGHTS & PERMISSIONS

The Author(s), under exclusive licence to the Huazhong University of Science and Technology