Coordinated transcriptional and post-transcriptional epigenetic regulation during skeletal muscle development and growth in pigs

N6-methyladenosine (m6A) and DNA 5-methylcytosine (5mC) methylation plays crucial roles in diverse biological processes, including skeletal muscle development and growth. Recent studies unveiled a potential link between these two systems, implicating the potential mechanism of coordinated transcriptional and post-transcriptional regulation in porcine prenatal myogenesis and postnatal skeletal muscle growth.

Our study discloses a potential epigenetic mechanism in skeletal muscle development and provides a novel direction for animal breeding and drug development of related human muscle-related diseases.

Immunofluorescence and co-IP assays were carried out between the 5mC writers and m6A writers to investigate the molecular basis underneath. Large-scale in-house transcriptomic data were compiled for applying weighted correlation network analysis (WGCNA) to identify the co-expression patterns of m6A and 5mC regulators and their potential role in pig myogenesis. Whole-genome bisulfite sequencing (WGBS) and methylated RNA immunoprecipitation sequencing (MeRIP-seq) were performed on the skeletal muscle samples from Landrace pigs at four postnatal growth stages (days 30, 60, 120 and 180).

Significantly correlated expression between 5mC writers and m6A writers and co-occurrence of 5mC and m6A modification were revealed from public datasets of C2C12 myoblasts. The protein-protein interactions between the DNA methylase and the m6A methylase were observed in mouse myoblast cells. Further, by analyzing transcriptome data comprising 81 pig skeletal muscle samples across 27 developmental stages, we identified a 5mC/m6A epigenetic module eigengene and decoded its potential functions in pre- or post-transcriptional regulation in postnatal skeletal muscle development and growth of pigs. Following integrative multi-omics analyses on the WGBS methylome data and MeRIP-seq data for both m6A and gene expression profiles revealed a genome/transcriptome-wide correlated dynamics and co-occurrence of 5mC and m6A modifications as a consequence of 5mC/m6A crosstalk in the postnatal myogenesis progress of pigs. Last, we identified a group of myogenesis-related genes collaboratively regulated by both 5mC and m6A modifications in postnatal skeletal muscle growth in pigs. Conclusions: Our study discloses a potential epigenetic mechanism in skeletal muscle development and provides a novel direction for animal breeding and drug development of related human muscle-related diseases.