title: Requirement of mitogen-activated protein kinase for collagenase production by the fibronectin fragment in human articular chondrocytes in culture.
abstract: Fibronectin fragments have been shown to up-regulate matrix metalloproteinase production in chondrocytes. We investigated the roles of mitogen-activated protein kinase (MAPK) pathways activated by the COOH-terminal heparin-binding fibronectin fragment (HBFN-f) in collagenase production by human chondrocytes in culture. In articular cartilage explant culture, HBFN-f stimulated type II collagen cleavage by collagenase in association with increased secretion of MMP-1 and MMP-13. In human articular chondrocytes, HBFN-f induced the collagenases with activation of the extracellular signal-regulated kinase (ERK), p38, and the c-Jun NH(2)-terminal kinase (JNK). PD98059 that inhibits the ERK pathway blocked HBFN-f-stimulated production of MMP-1 and MMP-13 in explant culture. SB203580 at 1 microM, the concentration that inhibits p38 only, partially suppressed HBFN-f-induced collagenase production, whereas at 10 microM, the inhibitor that blocks both p38 and JNK almost completely inhibited collagenase induction. PD98059 and SB203580 individually blocked HBFN-f-increased cleavage of type II collagen in the explant culture, although 10 microM SB203580 strongly inhibited the collagen cleavage compared with 1 microM of the inhibitor. These results indicate that collagenase production leading to type II collagen cleavage in cartilage explants requires ERK, p38, and JNK.
authors.affiliation: Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan, tadyasu@kuhp.kyoto-u.ac.jp.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yasuda
authors.forename: Sohel M
authors.initials: SM
authors.lastname: Julovi
authors.forename: Teruko
authors.initials: T
authors.lastname: Hiramitsu
authors.forename: Makoto
authors.initials: M
authors.lastname: Yoshida
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakamura