title: Origin and hierarchy of basal lamina-forming and -non-forming myogenic cells in mouse skeletal muscle in relation to adhesive capacity and Pax7 expression in vitro.
abstract: As a novel approach to distinguish skeletal myogenic cell populations, basal lamina (BL) formation of myogenic cells was examined in the mouse compensatory enlarged plantaris muscles in vivo and in fiber-bundle cultures in vitro. MyoD(+) myogenic cells located inside the regenerative muscle fiber BL were laminin(-) but interstitial MyoD(+) cells were laminin(+). This was also confirmed by electron microscopy as structural BL formation. Similar trends were observed in the fiber-bundle cultures including satellite cells and interstitial myogenic cells and laminin(+) myogenic cells predominantly showed non-adhesive (non-Ad) behavior with Pax7(-), whereas laminin(-) cells were adhesive (Ad) with Pax7(+). Moreover, non-Ad/laminin(+) and Ad/laminin(-) myotubes were also observed and the former type showed spontaneous contractions, while the latter type did not. The origin and hierarchy of Ad/Pax7(+)/laminin(-) and non-Ad/Pax7(-)/laminin(+) myogenic cells were also examined using skeletal muscle interstitium-derived CD34(+)/45(-) (Sk-34) and CD34(-)/45(-) (Sk-DN) multipotent stem cells, which were composed of non-committed myogenic cells with a few (<1%) Pax7(+) cells in the Sk-DN cells at fresh isolation. Both cell types were separated by Ad/non-Ad capacity in repetitive culture. As expected, both Ad/Pax7(+)/laminin(-) and non-Ad/Pax7(-)/laminin(+) myogenic cells consistently appeared in the Ad and non-Ad cell culture. However, Ad/Pax7(+)/laminin(-) cells were repeatedly detected in the non-Ad cell culture, while the opposite phenomenon did not occur. This indicates that the source of non-Ad/ Pax7(-)/laminin(+) myogenic cells was present in the Sk-34 and Sk-DN stem cells and they were able to produce Ad/ Pax7(+)/ laminin(-) myogenic cells during myogenesis as primary myoblasts and situated hierarchically upstream of the latter cells.
authors.affiliation: Muscle Physiology and Cell Biology Unit, Department of Regenerative Medicine, Division of Basic Clinical Science, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan. tamaki@is.icc.u-tokai.ac.jp
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Tamaki
authors.forename: Kayoko
authors.initials: K
authors.lastname: Tono
authors.forename: Yoshiyasu
authors.initials: Y
authors.lastname: Uchiyama
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Okada
authors.forename: Maki
authors.initials: M
authors.lastname: Masuda
authors.forename: Shuichi
authors.initials: S
authors.lastname: Soeda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nitta
authors.forename: Akira
authors.initials: A
authors.lastname: Akatsuka
mesh_terms: D000818:Animals; D002448:Cell Adhesion; D002460:Cell Line; D002478:Cells, Cultured; D003893:Desmin / Q000032:analysis / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D019012:Integrin beta1 / Q000235:genetics; D007797:Laminin / Q000032:analysis / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D024510:Muscle Development; D018485:Muscle Fibers, Skeletal / Q000166:cytology* / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology* / Q000648:ultrastructure; D017570:MyoD Protein / Q000032:analysis / Q000235:genetics; D018008:Myogenin / Q000032:analysis / Q000235:genetics; D051763:PAX7 Transcription Factor / Q000032:analysis / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D003893:Desmin; D019012:Integrin beta1; D007797:Laminin; D017570:MyoD Protein; D018008:Myogenin; D051763:PAX7 Transcription Factor