Lactiplantibacillus plantarum WY2401 promotes myogenesis via riboflavin-mediated modulation of METTL3-dependent mRNA m6A methylation.

INTRODUCTION: Lactiplantibacillus plantarum (L. plantarum) is a well-characterized probiotic with a long history of safe application, exhibiting prominent potential in improving skeletal muscle function. As the most prevalent and plentiful mRNA modification in eukaryotes, extensive research has highlighted the non-negligible role of N6-methyladenosine (m6A) in regulating various aspects of skeletal muscle biology. However, the underlying mechanisms through which L. plantarum-derived signals regulate host myogenic programs, as well as whether m6A modification is involved in this process, remain unclear. OBJECTIVE: To explore the microbe-host regulatory axis through which L. plantarum promotes skeletal muscle regeneration and whether m6A modification is involved in this process. METHODS: The cardiotoxin-induced muscle injury mouse model was constructed to investigate the impact of L. plantarum WY2401 on skeletal muscle regeneration. Untargeted metabolomics analysis was used to screen out L. plantarum WY2401-derived key metabolite. The changes in m6A modification were determined using dot blot and MeRIP-qPCR. RESULTS: We identified L. plantarum WY2401 as a pro-myogenic probiotic that promotes skeletal muscle regeneration. Specifically, L. plantarum WY2401 strongly alters circulating metabolomic profiles, particularly elevating the production of microbiota-derived riboflavin. Upregulated riboflavin is transported to skeletal muscle through the bloodstream, where it modulates the expression of the m6A methyltransferase METTL3 in a stage-dependent manner during myogenesis. This modulation promotes myoblast proliferation by enhancing the stability of Cdk2 and Ccnd1 mRNAs through the METTL3-m6A-YTHDF1 pathway. It also facilitates myoblast differentiation by increasing Mef2a mRNA stability through the METTL3-m6A-YTHDF2 pathway. CONCLUSION: Our findings reveal a novel microbe-host regulatory axis through which L. plantarum WY2401 promotes skeletal muscle regeneration via stage-specific epigenetic modulation of myogenesis. This work highlights the potential of L. plantarum as a functional probiotic supplement for improving skeletal muscle development and provides new insights into probiotic-mediated regulation of muscle regeneration.