title: In vivo gene transfer of PPAR gamma is insufficient to induce adipogenesis in skeletal muscle.
abstract: Skeletal muscle contains several progenitor/stem cells with myogenicity as well as adipogenicity such as satellite cells. Our previous study demonstrated that forced expression of PPAR gamma is sufficient to induce transdifferentiation of predetermined myoblasts in vitro. In the present study, we examined whether introduction of PPAR gamma gene could induce adipogenesis of satellite cells in vivo. A plasmid vector containing enhanced green fluorescent protein (EGFP) or PPAR gamma gene was introduced into rat tibialis anterior muscle by electroporation. Histological analyses revealed that electroporation induces degenerative/regenerative response in skeletal muscle, including activation of satellite cells. When EGFP gene was introduced, newly formed myotubes resulted from fusion of activated satellite cells, showed EGFP expression, indicating that electroporation could transfect satellite cells with exogenously introduced gene. Gene transfer of PPAR gamma resulted in an increase of PPAR gamma-positive mononucleated cells on day 3 after electroporation but failed to induce adipogenesis thereafter. These results suggested that, in addition to an expression of PPAR gamma, niches that support adipogenesis are required for satellite cells to enter adipogenesis in vivo.
authors.affiliation: Department of Veterinary Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Ban
authors.forename: Keitaro
authors.initials: K
authors.lastname: Yamanouchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsuwaki
authors.forename: Masugi
authors.initials: M
authors.lastname: Nishihara
mesh_terms: D017667:Adipocytes / Q000166:cytology; D050156:Adipogenesis / Q000502:physiology*; D000818:Animals; D018274:Electroporation / Q000379:methods; D018014:Gene Transfer Techniques; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics; D008297:Male; D018482:Muscle, Skeletal / Q000166:cytology* / Q000502:physiology*; D047495:PPAR gamma / Q000235:genetics*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D047495:PPAR gamma; D049452:Green Fluorescent Proteins