title: Enhanced expression of fibronectin by cmd/cmd chondrocytes and its modulation by exogenously added proteoglycan.
abstract: Cartilage matrix deficiency (cmd/cmd) in mice is a genetic disorder associated with the failure of chondrocytes to synthesize the core protein of cartilage proteoglycan monomer (cartilage-PG). Immunohistochemical and biochemical analyses revealed enhanced accumulation of fibronectin in culture of cmd/cmd chondrocytes as well as in mutant cartilage tissue in vivo. Purified cartilage-PG, when added exogenously to a culture of cmd/cmd chondrocytes, caused a reduction in abnormal accumulation of fibronectin over several subsequent days of culturing. Using a fibronectin cDNA probe, we showed that, on the basis of total RNA, the fibronectin mRNA level was four or eight times higher in cmd/cmd chondrocytes than in the normal. The level of fibronectin mRNA in cmd/cmd cells was lowered by culturing the cells in the presence of added cartilage-PG. These findings suggest that the abnormal accumulation of fibronectin in the mutant cell culture is primarily due to elevation of fibronectin mRNA level, and that cartilage-PG in the extracellular matrix may affect the regulation of fibronectin biosynthesis at the steady-state level of mRNA.
authors.affiliation: Institute for Molecular Science of Medicine, Aichi Medical University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tsukahara
authors.forename: M
authors.initials: M
authors.lastname: Okamura
authors.forename: S
authors.initials: S
authors.lastname: Suzuki
authors.forename: H
authors.initials: H
authors.lastname: Iwata
authors.forename: T
authors.initials: T
authors.lastname: Miura
authors.forename: K
authors.initials: K
authors.lastname: Kimata
mesh_terms: D000818:Animals; D002357:Cartilage Diseases / Q000235:genetics* / Q000378:metabolism; D002358:Cartilage, Articular / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured / Q000187:drug effects; D005353:Fibronectins / Q000032:analysis* / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects*; D051379:Mice; D008817:Mice, Mutant Strains; D011509:Proteoglycans / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis
chemical_list: D005353:Fibronectins; D011509:Proteoglycans; D012333:RNA, Messenger