title: Myotubes differentiate optimally on substrates with tissue-like stiffness: pathological implications for soft or stiff microenvironments.
abstract: Contractile myocytes provide a test of the hypothesis that cells sense their mechanical as well as molecular microenvironment, altering expression, organization, and/or morphology accordingly. Here, myoblasts were cultured on collagen strips attached to glass or polymer gels of varied elasticity. Subsequent fusion into myotubes occurs independent of substrate flexibility. However, myosin/actin striations emerge later only on gels with stiffness typical of normal muscle (passive Young's modulus, E approximately 12 kPa). On glass and much softer or stiffer gels, including gels emulating stiff dystrophic muscle, cells do not striate. In addition, myotubes grown on top of a compliant bottom layer of glass-attached myotubes (but not softer fibroblasts) will striate, whereas the bottom cells will only assemble stress fibers and vinculin-rich adhesions. Unlike sarcomere formation, adhesion strength increases monotonically versus substrate stiffness with strongest adhesion on glass. These findings have major implications for in vivo introduction of stem cells into diseased or damaged striated muscle of altered mechanical composition.
authors.affiliation: School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Engler
authors.forename: Maureen A
authors.initials: MA
authors.lastname: Griffin
authors.forename: Shamik
authors.initials: S
authors.lastname: Sen
authors.forename: Carsten G
authors.initials: CG
authors.lastname: Bönnemann
authors.forename: H Lee
authors.initials: HL
authors.lastname: Sweeney
authors.forename: Dennis E
authors.initials: DE
authors.lastname: Discher
mesh_terms: D000180:Acrylic Resins / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion; D002454:Cell Differentiation; D002460:Cell Line; D002478:Cells, Cultured; D004548:Elasticity; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D019085:Fluorescent Antibody Technique, Direct; D005782:Gels; D051379:Mice; D008809:Mice, Inbred C3H; D008817:Mice, Mutant Strains; D018625:Microscopy, Atomic Force; D008954:Models, Biological; D018485:Muscle Fibers, Skeletal / Q000473:pathology* / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D013379:Substrate Specificity; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D005782:Gels; D000099166:Polyacrylamides