title: N-butyryl glucosamine increases matrix gene expression by chondrocytes.
abstract: Proteoglycan synthesis is dependent on N-acetyl glucosamine (GlcNAc) produced by the hexosamine biosynthetic pathway or obtained exogenously. Although used therapeutically to relieve symptoms of osteoarthritis, the actions of glucosamine and its analogs on cartilage are poorly understood. The purpose of this study was to determine the effects on chondrocytes of N-acylated-glucosamine analogs bearing alkyl chains of different lengths. Chondrocytes isolated from neonatal rat femoral condyles were cultured in the presence of glucosamine analogs. GlcNAc, N-proprionyl glucosamine (GlcNPro), or N-butyryl glucosamine (GlcNBu) did not alter cell number, lactate dehydrogenase release, or metabolic acid production, consistent with lack of cytotoxicity. Treatment of chondrocyte cultures with GlcNBu for 6 days significantly increased levels of type II collagen and aggrecan mRNA as determined by Northern blot analysis. In contrast, GlcNAc and GlcNPro had no significant effect. A significant increase in type II collagen mRNA was induced by GlcNBu within 3 days. GlcNBu did not alter stability of type II collagen mRNA, suggesting it acts on gene transcription. We have previously shown that tumor necrosis factor-alpha (TNFalpha) decreases levels of type II collagen mRNA. However, chondrocytes pretreated with GlcNBu maintained type II collagen mRNA at control levels in the presence of TNFalpha. These results establish that the N-butyrylated analog of glucosamine but not GlcNAc promotes matrix gene expression by chondrocytes. Thus, GlcNBu has the potential for use as a chondro-protective agent in osteoarthritis.
authors.affiliation: Canadian Institutes of Health Research Group in Skeletal Development and Remodeling, Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario, Canada, N6A 5C1.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Poustie
authors.forename: John
authors.initials: J
authors.lastname: Carran
authors.forename: Kevin
authors.initials: K
authors.lastname: McEleney
authors.forename: S Jeffrey
authors.initials: SJ
authors.lastname: Dixon
authors.forename: Tassos P
authors.initials: TP
authors.lastname: Anastassiades
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Bernier
mesh_terms: D053674:Aggrecans; D000818:Animals; D002356:Cartilage / Q000187:drug effects / Q000378:metabolism; D002452:Cell Count; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects* / Q000378:metabolism; D024043:Collagen Type II / Q000235:genetics / Q000378:metabolism*; D004347:Drug Interactions; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects*; D005944:Glucosamine / Q000737:chemistry / Q000494:pharmacology; D037181:Lectins, C-Type; D011509:Proteoglycans / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: C508321:Acan protein, rat; D053674:Aggrecans; D024043:Collagen Type II; D016326:Extracellular Matrix Proteins; D037181:Lectins, C-Type; D011509:Proteoglycans; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D005944:Glucosamine