Ginsenoside Rb1 and Rb2 upregulate Akt/mTOR signaling–mediated muscular hypertrophy and myoblast differentiation

• Published in: Journal of ginseng research Vol. 44; no. 3; pp. 435 - 441
• Main Authors: Go, Ga-Yeon, Jo, Ayoung, Seo, Dong-Wan, Kim, Woo-Young, Kim, Yong Kee, So, Eui-Young, Chen, Qian, Kang, Jong-Sun, Bae, Gyu-Un, Lee, Sang-Jin
• Format: Journal Article
• Language: English
• Published: Korea (South) Elsevier B.V 01.05.2020; Elsevier; 고려인삼학회
• Subjects: Akt/mTOR signaling; AMP-activated protein kinase; dimerization; fibroblasts; ginsenosides; glucose; homeostasis; Hypertrophy; immunoblotting; mammals; muscle development; muscles; muscular atrophy; muscular dystrophy; Myoblast differentiation; myoblasts; myogenin; myosin heavy chains; myotubes; oxidative stress; Panax; Pharmacology and physiology; precipitin tests; rapamycin; Rb1; Rb2; skeletal muscle; 기타의약학; Rb1; Akt/mTOR signaling; Rb2; Myoblast differentiation; Hypertrophy
• DOI: 10.1016/j.jgr.2019.01.007
• ISSN: 1226-8453

As a process of aging, skeletal muscle mass and function gradually decrease. It is reported that ginsenoside Rb1 and Rb2 play a role as AMP-activated protein kinase activator, resulting in regulating glucose homeostasis, and Rb1 reduces oxidative stress in aged skeletal muscles through activating the phosphatidylinositol 3-kinase/Akt/Nrf2 pathway. We examined the effects of Rb1 and Rb2 on differentiation of the muscle stem cells and myotube formation. C2C12 myoblasts treated with Rb1 and/or Rb2 were differentiated and induced to myotube formation, followed by immunoblotting for myogenic marker proteins, such as myosin heavy chain, MyoD, and myogenin, or immunostaining for myosin heavy chain or immunoprecipitation analysis for heterodimerization of MyoD/E-proteins. Rb1 and Rb2 enhanced myoblast differentiation through accelerating MyoD/E-protein heterodimerization and increased myotube hypertrophy, accompanied by activation of Akt/mammalian target of rapamycin signaling. In addition, Rb1 and Rb2 induced the MyoD-mediated transdifferentiation of the rhabdomyosarcoma cells into myoblasts. Furthermore, co-treatment with Rb1 and Rb2 had synergistically enhanced myoblast differentiation through Akt activation. Rb1 and Rb2 upregulate myotube growth and myogenic differentiation through activating Akt/mammalian target of rapamycin signaling and inducing myogenic conversion of fibroblasts. Thus, our first finding indicates that Rb1 and Rb2 have strong potential as a helpful remedy to prevent and treat muscle atrophy, such as age-related muscular dystrophy.