Loss of Myostatin Shapes the Transcriptomic and Epigenetic Landscapes Across Multiple Muscle Types in Cattle

Myostatin (MSTN) is a critical regulator of muscle development. This study aimed to investigate the transcriptional and epigenetic mechanisms by which MSTN gene editing affects skeletal, cardiac, and smooth muscle function in cattle. The results showed that the MSTN gene-edited (MT) cattle skeletal muscle exhibited significantly larger myofiber cross-sectional areas (p = 0.049), accompanied by reduced shear force (p = 0.044), cooking loss rate (p = 0.0029), and pH (p = 0.014). Transcriptomic and whole-genome bisulfite sequencing (WGBS) revealed distinct expression and methylation patterns across muscle types. Notably, axon guidance signaling was identified as a shared enriched pathway in both transcriptional and CG/CHG/CHH methylation profiles of the gluteus. Further, 102 differentially expressed genes (DEGs) were commonly identified across all three muscle types; their KEGG enrichment included immune-related and cellular interaction pathways (e.g., antigen processing and presentation, and cell adhesion molecules), many of which intersect with axon guidance functions. Core regulators such as SEMA3A, PLXNA1, and NTN1 were epigenetically modulated in MT gluteus and heart. These findings suggest that MSTN knockout remodels neuromuscular signaling through muscle-type-specific transcriptional and epigenetic reprogramming.