title: Enhanced contractile force generation by artificial skeletal muscle tissues using IGF-I gene-engineered myoblast cells.
abstract: The aim of this study was to investigate whether insulin-like growth factor (IGF)-I gene delivery to myoblast cells promotes the contractile force generated by hydrogel-based tissue-engineered skeletal muscles in vitro. Two retroviral vectors allowing doxycycline (Dox)-inducible expression of the IGF-I gene were transduced into mouse myoblast C2C12 cells to evaluate the effects of IGF-I gene expression on these cells. IGF-I gene expression stimulated the proliferation of C2C12 cells, and a significant increase in the growth rate was observed for IGF-I-transduced C2C12 cells with Dox addition, designated C2C12/IGF (Dox+) cells. Quantitative morphometric analyses showed that the myotubes induced from C2C12/IGF (Dox+) cells had a larger area and a greater width than control myotubes induced from normal C2C12 cells. Artificial skeletal muscle tissues were prepared from the respective cells using hydrogels composed of type I collagen and Matrigel. Western blot analyses revealed that the C2C12/IGF (Dox+) tissue constructs showed activation of a skeletal muscle hypertrophy marker (Akt) and enhanced expression of muscle-specific markers (myogenin, myosin heavy chain and tropomyosin). Moreover, the creatine kinase activity was increased in the C2C12/IGF (Dox+) tissue constructs. The C2C12/IGF (Dox+) tissue constructs contracted in response to electrical pulses, and generated a significantly higher physical force than the control C2C12 tissue constructs. These findings indicate that IGF-I gene transfer has the potential to yield functional skeletal muscle substitutes that are capable of in vivo restoration of the load-bearing function of injured muscle or acting as in vitro electrically-controlled bio-actuators.
authors.affiliation: Department of Chemical Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Sato
authors.forename: Akira
authors.initials: A
authors.lastname: Ito
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kawabe
authors.forename: Eiji
authors.initials: E
authors.lastname: Nagamori
authors.forename: Masamichi
authors.initials: M
authors.lastname: Kamihira
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D003094:Collagen; D004338:Drug Combinations; D005822:Genetic Vectors; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics* / Q000378:metabolism; D007797:Laminin; D051379:Mice; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000166:cytology* / Q000378:metabolism; D032446:Myoblasts / Q000166:cytology / Q000378:metabolism; D010766:Phosphorylation; D011509:Proteoglycans; D013002:Somatomedins / Q000378:metabolism; D023822:Tissue Engineering / Q000379:methods*; D016474:Weight-Bearing
chemical_list: D004338:Drug Combinations; D007797:Laminin; D011509:Proteoglycans; D013002:Somatomedins; C059485:matrigel; D007334:Insulin-Like Growth Factor I; D003094:Collagen