title: Rapamycin represses myotube hypertrophy and preserves viability of C2C12 cells during myogenesis in vitro.
abstract: BACKGROUND
  Rapamycin (RAPA) has been successfully used for myoblast allotransplantation in X chromosome-linked muscular dystrophy mice. However, the mechanism of skeletal myogenesis, particularly in starved condition by RAPA, remains elusive. For this reason, we investigated the effect of RAPA on C2C12 myogenesis in serum-starved condition.
  
  
  METHODS
  Serum-free treated C2C12 cells were mimicked as skeletal myogenesis in nutrition shortage microenvironment. A methylthiazoletetrazolium (MTT) assay was used to investigate different RAPA concentrations on serum-free treated C2C12 cells and the following assays were used to detect the characteristic of C2C12 myogenesis by RAPA in vitro.
  
  
  RESULTS
  We found that 150 ng/mL of RAPA did not significantly suppress the viability of C2C12 differentiated cells by MTT assay. The RAPA concentration could protect myoblast serum-starved cells effectively from apoptosis through flow cytometry and retain myogenic regulatory factors through quantitative polymerase chain reaction analysis. However, RAPA significantly suppressed cell migration in wound healing assay (P<0.05). Morphological analyses indicated that RAPA also significantly suppressed myotube hypertrophy in serum-starved C2C12 cells. Western blot analysis revealed that the ratio of phosphate extracellular signal-regulated kinase/extracellular signal-regulated kinase and the protein level of p-Akt decreased in the proliferation medium and in the differentiation medium, respectively.
  
  
  CONCLUSIONS
  These findings suggest that myoblast cells are sensitive to RAPA under a serum-starved microenvironment. As an immunosuppressive agent, RAPA shall be used as a considering dosage and as a safe strategy for future myoblast allotransplantation.
authors.affiliation: 1 Institute of Resource Biology and Biotechnology, Department of Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China. 2 Key Laboratory of Molecular Biophysics Ministry of Education, Huazhong University of Science and Technology, Wuhan, China. 3 Wuhan Institute of Biotechnology, Wuhan, China. 4 Department of Chemical Engineering and Food Science, Hubei University of Arts and Science, Hubei, China. 5 Address correspondence to: Mingzhang Ao, Ph.D., Longjiang Yu, Ph.D., College of Life Science and Technology, Huazhong University of Science and Technology, No. 1037 Luoyu Road, Wuhan 430074, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Gao
authors.forename: Mingzhang
authors.initials: M
authors.lastname: Ao
authors.forename: Haiyan
authors.initials: H
authors.lastname: Wang
authors.forename: Longjiang
authors.initials: L
authors.lastname: Yu
mesh_terms: D000818:Animals; D002459:Cell Fusion; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D016895:Culture Media, Serum-Free; D004305:Dose-Response Relationship, Drug; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005786:Gene Expression Regulation; D006984:Hypertrophy; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D051379:Mice; D024510:Muscle Development / Q000187:drug effects*; D032446:Myoblasts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D020123:Sirolimus / Q000494:pharmacology*; D013997:Time Factors; D014945:Wound Healing / Q000187:drug effects
chemical_list: D016895:Culture Media, Serum-Free; D007166:Immunosuppressive Agents; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D020123:Sirolimus