title: Disruption of endogenous perlecan function improves differentiation of rat articular chondrocytes in vitro.
abstract: Heparan sulfate (HS) and heparan sulfate proteoglycans (HSPG) are necessary for normal cartilage development and chondrocyte differentiation. However, recent studies demonstrated that HSPG accelerate dedifferentiation and catabolism in chondrocytes from degenerative cartilage. In this study, we investigated the inhibitory effect of HSPG on chondrocyte differentiation in vitro. Rat articular chondrocytes were cultured at low (0.3 × 10(4) cells/cm(2) ) and high (1.5 × 10(5) cells/cm(2) ) density in the presence or absence of heparitinase I, an HS degrading enzyme. Cells cultured at low density dedifferentiated and exhibited an elongated morphology, and treatment with heparitinase I precluded cell elongation. Conversely, populations of chondrocytes cultured at high density exhibited either a dedifferentiated or differentiated phenotype. Glycosaminoglycan accumulation increased in heparitinase I-treated cells. To determine the function of perlecan, an important HSPG for cartilage development, in chondrocyte differentiation, rat chondrocyte cultures were exposed to an anti-perlecan antiserum to inhibit perlecan function. Western blotting analysis indicated that preventing perlecan activity increased type II collagen synthesis. Our results suggest that HSPG are negative regulators of chondrocyte differentiation in vitro and that perlecan contributes to chondrocyte dedifferentiation in vitro.
authors.affiliation: Laboratory of Animal By-Product Science, Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Nakamura
authors.forename: Fumio
authors.initials: F
authors.lastname: Nakamura
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Fukunaga
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology; D002454:Cell Differentiation / Q000235:genetics*; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism; D024043:Collagen Type II / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism; D019812:Heparan Sulfate Proteoglycans / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000502:physiology*; D007106:Immune Sera / Q000494:pharmacology; D011133:Polysaccharide-Lyases / Q000494:pharmacology; D017208:Rats, Wistar
chemical_list: D024043:Collagen Type II; D006025:Glycosaminoglycans; D019812:Heparan Sulfate Proteoglycans; D007106:Immune Sera; C071927:perlecan; D011133:Polysaccharide-Lyases; C021349:heparitinsulfate lyase
keywords: HS; HSPG; culture; extracellular matrix; perlecan