Allophycocyanin enhances myogenic differentiation and reverses canagliflozin-induced inhibition in C2C12 myoblasts

Canagliflozin (CANA), a sodium-glucose co-transporter 2 (SGLT2) inhibitor widely prescribed for type 2 diabetes, has been reported to impair skeletal muscle regeneration and differentiation. This study investigated the potential effect of allophycocyanin (APC), a phycobiliprotein found in cyanobacteria such as Spirulina platensis, on myotube formation of C2C12 myoblasts and its ability to prevent or reverse canagliflozin-induced inhibition of myogenesis. Immunofluorescence staining with Western blotting was performed to examine the effects of APC or CANA on myotube formation while exploring possible underlying mechanisms. Flow cytometry along with Transwell migration assay was used to evaluate cell-cycle exit and migration. APC increased C2C12 differentiation into myotubes by about 85% and activated the IGF-1R/AKT/mTOR signaling pathway and its downstream target p70S6K, stimulated myoblast migration along with increases in phosphorylation of FAK and paxillin, and partly reversed CANA-induced inhibition of myogenesis by activating AKT/mTOR and suppressing the expression of MuRF1. In summary, APC promoted C2C12 myogenic differentiation and migration through the IGF-1R/AKT/mTOR and FAK/paxillin pathways and attenuated canagliflozin-induced inhibition of myogenesis by activating AKT/mTOR signaling and suppressing MuRF1, suggesting that APC could potentially be used to develop a nutraceutical for supporting skeletal muscle regeneration in patients receiving SGLT2 inhibitors.