title: Redifferentiation of dedifferentiated chondrocytes on chitosan membranes and involvement of PKCalpha and P38 MAP kinase.
abstract: To investigate the effects of chitosan on the redifferentiation of dedifferentiated chondrocytes, we used chondrocytes obtained from a micromass culture system. Micromass cultures of chick wing bud mesenchymal cells yielded differentiated chondrocytes, but these dedifferentiated during serial monolayer subculture. When the dedifferentiated chondrocytes were cultured on chitosan membranes they regained the phenotype of differentiated chondrocytes. Expression of protein kinase C (PKC) increased during chondrogenesis, decreased during dedifferentiation, and increased again during redifferentiation. Treatment of the cultures with phorbol 12-myristate 13-acetate (PMA) inhibited redifferentiation and down-regulated PKC. In addition, the expression of p38 mitogen-activated protein (MAP) kinase increased during redifferentiation, and its inhibition suppressed redifferentiation. These findings establish a culture system for producing chondrocytes, point to a new role of chitosan in the redifferentiation of dedifferentiated chondrocytes, and show that PKC and p38 MAP kinase activities are required for chondrocyte redifferentiation in this model system.
authors.affiliation: Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu 702-701, Korea.
authors.forename: Yoon Ae
authors.initials: YA
authors.lastname: Lee
authors.forename: Shin-Sung
authors.initials: SS
authors.lastname: Kang
authors.forename: Suk-Hwan
authors.initials: SH
authors.lastname: Baek
authors.forename: Jae-Chang
authors.initials: JC
authors.lastname: Jung
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Jin
authors.forename: Eun Nam
authors.initials: EN
authors.lastname: Tak
authors.forename: Jong Kyung
authors.initials: JK
authors.lastname: Sonn
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D002642:Chick Embryo; D048271:Chitosan; D019902:Chondrocytes / Q000502:physiology*; D015536:Down-Regulation; D005121:Extremities / Q000196:embryology; D051571:Protein Kinase C-alpha / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology*
chemical_list: D048271:Chitosan; D051571:Protein Kinase C-alpha; D048051:p38 Mitogen-Activated Protein Kinases; D013755:Tetradecanoylphorbol Acetate