Molecular Insights into Central Core Disease: Proteomic Signatures and Potential Therapeutic Biomarkers in RYR1 I4895T Mice

Central Core Disease (CCD) is a congenital myopathy predominantly caused by mutations in the gene encoding ryanodine receptor type-1 (RYR1), the intracellular Ca2+ release channel embedded in the skeletal muscle sarcoplasmic reticulum membrane. The I4898T mutation represents one of the most common RYR1 mutations associated with CCD. Unfortunately, there are no approved therapies for CCD or for other myopathies caused by mutations in this gene. This study aims to perform a top-down differential proteomic analysis on soleus muscle samples from wild-type mice (WT) and heterozygous knock-in mice carrying the I4895T (IT) mutation in RyR1, to investigate the pathogenic mechanisms and molecular pathways involved in this myopathy and to shed light on new potential biomarkers useful for future therapies. Proteomic analysis revealed 50 dysregulated protein species, and multivariate analysis showed that IT mice exhibit a distinct proteomic signature compared to WT mice, characterized by alterations in proteins associated with contractile and structural dysfunction, metabolism, and stress response. In particular, a significant increase in myosin fragments was observed in IT mice, likely due to muscle breakdown. In contrast, myotilin was downregulated, suggesting a weakening of the muscle cytoskeletal structure. There was a notable downregulation of proteins involved in glycolysis and the TCA cycle; conversely, there was an increase in proteins related to anaerobic glycolysis, suggesting a shift from aerobic to anaerobic glycolysis. Furthermore, proteins involved in fatty acid beta-oxidation and oxidative phosphorylation were also found to be upregulated in IT mice, indicating an attempt by the muscle to maximize energy production. Finally, we found a significant decrease in PGC1 alpha, which could serve as potential therapy target and biomarker in CCD.