title: 3-D in vitro model of early skeletal muscle development.
abstract: An understanding of the mechanical and mechano-molecular responses that occur during the differentiation of mouse C2C12 [corrected] myoblasts in 3-D culture is critical for understanding growth, which is important for progress towards producing a tissue-engineered muscle construct. We have established the main differences in force generation between skeletal myoblasts, dermal fibroblasts, and smooth muscle cells in a 3-D culture model in which cells contract a collagen gel construct. This model was developed to provide a reproducible 3-D muscle organoid in which differences in force generation could be measured, as the skeletal myoblasts fused to form myotubes within a collagen gel. Maintenance of the 3-D culture under sustained uni-axial tension, was found to promote fusion of myoblasts to form aligned multi-nucleate myotubes. Gene expression of both Insulin Like Growth Factor (IGF-1 Ea) and an isoform of IGF-1 Ea, Mechano-growth factor (IGF-1 Eb, also termed MGF), was monitored in this differentiating collagen construct over the time course of fusion and maturation (0-7 days). This identified a transient surge in both IGF-1 and MGF expression on day 3 of the developing construct. This peak of IGF-1 and MGF expression, just prior to differentiation, was consistent with the idea that IGF-1 stimulates differentiation through a Myogenin pathway [Florini et al., 1991: Mol. Endocrinol. 5:718-724]. MGF gene expression was increased 77-fold on day 3, compared to a 36-fold increase with IGF-1 on day 3. This indicates an important role for MGF in either differentiation or, more likely, a response to mechanical or tensional cues.
authors.affiliation: Tissue Repair and Engineering Centre, University College London, RFUCMS, Institute of Orthopaedics, RNOH, Stanmore, Middlesex, United Kingdom.
authors.forename: U
authors.initials: U
authors.lastname: Cheema
authors.forename: S-Y
authors.initials: SY
authors.lastname: Yang
authors.forename: V
authors.initials: V
authors.lastname: Mudera
authors.forename: G G
authors.initials: GG
authors.lastname: Goldspink
authors.forename: R A
authors.initials: RA
authors.lastname: Brown
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005347:Fibroblasts; D006801:Humans; D021621:Imaging, Three-Dimensional; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis; D051379:Mice; D008954:Models, Biological; D024510:Muscle Development; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D018482:Muscle, Skeletal / Q000254:growth & development*; D032448:Myoblasts, Skeletal / Q000166:cytology*; D011817:Rabbits; D013997:Time Factors
chemical_list: D007334:Insulin-Like Growth Factor I