title: N-acylation of glucosamine modulates chondrocyte growth, proteoglycan synthesis, and gene expression.
abstract: OBJECTIVE
  To examine the effects of glucosamine (GlcN) and some N-acylated (GlcNAcyl) derivatives on the proliferation and proteoglycan (PG) synthesis of bovine articular chondrocyte (BAC); and to expand these results to human articular chondrocytes (HAC) and study the modulation of gene regulation by these compounds.
  
  
  METHODS
  The compounds tested were: glucose (Glc), GlcN.HCl, N-acetyl GlcN (GlcNAc), and N-butyryl GlcN, (GlcNBu). GlcNBu was synthesized from GlcN and butyric anhydride. For the chondrocyte cultures, both anchorage-dependent (AD) and an anchorage-independent (AI) system (alginate beads) were evaluated. Following the various additions, BAC were assessed for total cell number, DNA, or total PG synthesis at different times. Utilizing similar conditions, human cDNA microarrays were performed for the HAC after harvesting total RNA.
  
  
  RESULTS
  For AD cultures, the addition of GlcN.HCl (0.1-5.0 mM) to BAC or HAC cultures inhibited cell proliferation and total PG synthesis in a dose-dependent manner. For AI cultures, the inhibitory effects of GlcN.HCl on cell proliferation were less prominent, and PG synthesis increased slightly more for the GlcNAcyl than the GlcN additions. In the AD system, the addition of GlcNAc did not result in the inhibitory effect of GlcN.HCl, while GlcNBu addition resulted in an increase in BAC proliferation and PG synthesis that could not be explained by the Bu moiety alone. For the HAC, additions of 0.1 mM GlcNBu resulted in upregulation of a large number of genes, with only a few downregulated, while GlcN addition resulted in no upregulation and one downregulated gene, for preset stringency criteria.
  
  
  CONCLUSIONS
  Addition of GlcNBu to BAC or HAC to AD cultures generally stimulated cell proliferation and PG synthesis, while addition of GlcN resulted in inhibition of these indicators. The inhibitory effects of the GlcN molecule appear to be related to the unsubstituted amino group. Additions of GlcNBu, but not GlcN, to HAC resulted in upregulation in the expression of a large number of genes.
authors.affiliation: Department of Medicine, Queen's University, Kingston, Ontario, Canada.
authors.forename: Doris E
authors.initials: DE
authors.lastname: Terry
authors.forename: Karen
authors.initials: K
authors.lastname: Rees-Milton
authors.forename: Patrick
authors.initials: P
authors.lastname: Smith
authors.forename: John
authors.initials: J
authors.lastname: Carran
authors.forename: Parvis
authors.initials: P
authors.lastname: Pezeshki
authors.forename: Craig
authors.initials: C
authors.lastname: Woods
authors.forename: Peter
authors.initials: P
authors.lastname: Greer
authors.forename: Tassos P
authors.initials: TP
authors.lastname: Anastassiades
mesh_terms: D000107:Acetylation; D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology; D002417:Cattle; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects*; D017077:Culture Media, Conditioned; D005786:Gene Expression Regulation; D005944:Glucosamine / Q000494:pharmacology*; D011509:Proteoglycans / Q000032:analysis / Q000096:biosynthesis*; D012016:Reference Values; D012680:Sensitivity and Specificity; D015854:Up-Regulation
chemical_list: D017077:Culture Media, Conditioned; D011509:Proteoglycans; D005944:Glucosamine