Additional effects of simultaneous treatment with C14-Cblin and celastrol on the clinorotation-induced rat L6 myotube atrophy

• Published in: The Journal of Medical Investigation Vol. 69; no. 1.2; pp. 127 - 134
• Main Authors: Kitahata, Kanako, Uchida, Takayuki, Taniguchi, Runa, Kato, Ayano, Sugiura, Kosuke, Sakakibara, Iori, Oarada, Motoko, Fukawa, Tomoya, Junsoo, Park, Inho, Choi, Nikawa, Takeshi
• Format: Journal Article
• Language: English
• Published: Japan The University of Tokushima Faculty of Medicine 2022
• Subjects: Animals; Atrophy - metabolism; Atrophy - pathology; C14-Cblin; celastrol; Humans; muscle atrophy-associated ubiquitin ligases; Muscle Fibers, Skeletal - metabolism; Muscle Fibers, Skeletal - pathology; myotube atrophy; oxidative stress; Pentacyclic Triterpenes - metabolism; Pentacyclic Triterpenes - pharmacology; Rats; Rotation; celastrol; myotube atrophy; muscle atrophy-associated ubiquitin ligases; C14-Cblin; oxidative stress
• ISSN: 1343-1420; 1349-6867
• DOI: 10.2152/jmi.69.127

Two novel reagents, N-myristoylated Cbl-b inhibitory peptide (C14-Cblin) and celastrol, a quinone methide triterpene, are reported to be effective in preventing myotube atrophy. The combined effects of C14-Cblin and celastrol on rat L6 myotubes atrophy induced by 3D-clinorotation, a simulated microgravity model, was investigated in the present study. We first examined their effects on expression in atrogenes. Increase in MAFbx1/atrogin-1 and MuRF-1 by 3D-clinorotation was significantly suppressed by treatment with C14-Cblin or celastrol, but there was no additive effect of simultaneous treatment. However, celastrol significantly suppressed the upregulation of Cbl-b and HSP70 by 3D-clinorotation. Whereas 3D-clinorotation decreased the protein level of IRS-1 in L6 myotubes, C14-Cblin and celastrol inhibited the degradation of IRS-1. C14-Cblin and celastrol promoted the phosphorylation of FOXO3a even in microgravity condition. Simultaneous administration of C14-Cblin and celastrol had shown little additive effect in reversing the impairment of IGF-1 signaling by 3D-clinorotation. While 3D-clinorotation-induced marked oxidative stress in L6 myotubes, celastrol suppressed 3D-clinorotation-induced ROS production. Finally, the C14-Cblin and celastrol-treated groups were inhibited decrease in L6 myotube diameter and increased the protein content of slow-twitch MyHC cultured under 3D-clinorotation. The simultaneous treatment of C14-Cblin and celastrol additively prevented 3D-clinorotation-induced myotube atrophy than single treatment. J. Med. Invest. 69 : 127-134, February, 2022