Transcriptome analysis of injured muscle identifies new candidate genes for satellite cell growth and myofiber formation during early muscle regeneration.

OBJECTIVE: The self-repair capacity of skeletal muscle makes satellite cell activity and myofiber formation interesting. The major molecular networks of satellite cell activity have been extensively studied. However, the mechanism by which micro-environmental factors regulate satellite cell activity for early muscle regeneration still remains poorly understood. METHODS: Control and injured muscle samples were stained with H&E and immunofluorescent for embryonic myosin heavy chain (eMyHC) at 12, 24, 36, 48, 60, 72, and 84 hours post-injury. Additionally, muscle samples from three mice were immunofluorescent for eMyHC 96 hours post-injury. RNA sequencing and quantitative polymerase chain reaction were performed on 24 mice, including controls and samples at 12-, 24-, and 84-hour post-injury. RESULTS: Significant upregulation of 516 immune-related and 177 hormone response-related genes was found in this study. Statistical analysis indicated that the number of differentially expressed genes (DEGs) associated with up- and down-regulated immune systemrelated DEGs was comparable to that of hormone response-related DEGs. The p53 signaling pathway was significantly enriched during early muscle regeneration. Analysis of crucial myogenic genes expression patterns yielded 326 and 320 candidate genes related to satellite cell growth and myofiber formation, respectively. Furthermore, interaction network analysis identified 41 immune factors, including S100a9, Csf3r, Cxcl3, Ppbp, Ccl3, Il-1rn, potentially regulating satellite cell activation, migration and proliferation. Likewise, 16 cell adhesion factors (Col1a2, Cdh2, Thbs2, etc.) may be involved in myofiber formation. CONCLUSION: This study utilized transcriptomic analysis to identify key candidate genes and biological processes involved in early muscle regeneration. The findings enhance our understanding of the molecular mechanisms underlying muscle repair and offer insights for future therapeutic strategies.