Lactobacillus curvatus CP2998 Prevents Dexamethasone-Induced Muscle Atrophy in C2C12 Myotubes

To investigate whether heat-killed Lactobacillus curvatus CP2998 (CP2998) inhibits glucocorticoid-induced myotube atrophy which is associated with the ubiquitin-proteasome system, mouse skeletal muscle C2C12 myotubes were treated with dexamethasone (DEX) in the presence or absence of CP2998. DEX exposure significantly decreased myotube diameters and increased mRNA expression levels of MuRF1 and MAFbx, E3 ubiquitin ligases. CP2998 treatment restored myotube diameters and dose dependently decreased mRNA expression levels of these E3 ubiquitin ligases. CP2998 treatment also inhibited DEX-induced glucocorticoid dependent transcription. Our results suggest that CP2998 prevents DEX-induced muscle atrophy by suppressing glucocorticoid receptor activation.