title: Ablation of Perlecan Domain 1 Heparan Sulfate Reduces Progressive Cartilage Degradation, Synovitis, and Osteophyte Size in a Preclinical Model of Posttraumatic Osteoarthritis.
abstract: OBJECTIVE
  To investigate the role of the heparan sulfate (HS) proteoglycan perlecan (HSPG-2) in regulating fibroblast growth factor (FGF) activity, bone and joint growth, and the onset and progression of posttraumatic osteoarthritis (OA) in a mouse gene-knockout model.
  
  
  METHODS
  Maturational changes were evaluated histologically in the knees of 3-, 6-, and 12-week-old wild-type (WT) mice and Hspg2(Δ3-/Δ3-) mice (Hspg2 lacking domain 1 HS, generated by ablation of exon 3 of perlecan). Cartilage damage, subchondral bone sclerosis, osteophytosis, and synovial inflammation were scored at 4 and 8 weeks after surgical induction of OA in WT and Hspg2(Δ3-/Δ3-) mice. Changes in cartilage expression of FGF-2, FGF-18, HSPG-2, FGF receptor 1 (FGFR-1), and FGFR-3 were examined immunohistochemically. Femoral head cartilage from both mouse genotypes was cultured in the presence or absence of interleukin-1α (IL-1α), FGF-2, and FGF-18, and the content and release of glycosaminoglycan (GAG) and expression of messenger RNA (mRNA) for key matrix molecules, enzymes, and inhibitors were quantified.
  
  
  RESULTS
  No effect of perlecan HS ablation on growth plate or joint development was detected. After induction of OA, Hspg2(Δ3-/Δ3-) mice had significantly reduced cartilage erosion, osteophytosis, and synovitis. OA-induced loss of chondrocyte expression of FGF-2, FGF-18, and HSPG-2 occurred in both genotypes. Expression of FGFR-1 after OA induction was maintained in WT mice, while FGFR-3 loss after OA induction was significantly reduced in Hspg2(Δ3-/Δ3-) mice. There were no genotypic differences in GAG content or release between unstimulated control cartilage and IL-1α-stimulated cartilage. However, IL-1α-induced cartilage expression of Mmp3 mRNA was significantly reduced in Hspg2(Δ3-/Δ3-) mice. Cartilage GAG release in either the presence or absence of IL-1α was unaltered by FGF-2 in both genotypes. In cartilage cultures with FGF-18, IL-1α-stimulated GAG loss was significantly reduced only in Hspg2(Δ3-/Δ3-) mice, and this was associated with maintained expression of Fgfr3 mRNA and reduced expression of Mmp2/Mmp3 mRNA.
  
  
  CONCLUSIONS
  Perlecan HS has significant roles in directing the development of posttraumatic OA, potentially via the alteration of FGF/HS/FGFR signaling. These data suggest that the chondroprotection conferred by perlecan HS ablation could be attributed, at least in part, to the preservation of FGFR-3 and increased FGF signaling.
authors.affiliation: Kolling Institute, Northern Sydney Local Health District, and the University of Sydney at Royal North Shore Hospital, St. Leonards, New South Wales, Australia.
authors.forename: Cindy C
authors.initials: CC
authors.lastname: Shu
authors.affiliation: Kolling Institute, Northern Sydney Local Health District, and the University of Sydney at Royal North Shore Hospital, St. Leonards, New South Wales, Australia.
authors.forename: Miriam T
authors.initials: MT
authors.lastname: Jackson
authors.affiliation: Kolling Institute, Northern Sydney Local Health District, and the University of Sydney at Royal North Shore Hospital, St. Leonards, New South Wales, Australia.
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Smith
authors.affiliation: Kolling Institute, Northern Sydney Local Health District, and the University of Sydney at Royal North Shore Hospital, St. Leonards, New South Wales, Australia.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Smith
authors.affiliation: University of New South Wales, Kensington, New South Wales, Australia.
authors.forename: Steven
authors.initials: S
authors.lastname: Penm
authors.affiliation: University of New South Wales, Kensington, New South Wales, Australia.
authors.forename: Megan S
authors.initials: MS
authors.lastname: Lord
authors.affiliation: University of New South Wales, Kensington, New South Wales, Australia.
authors.forename: John M
authors.initials: JM
authors.lastname: Whitelock
authors.affiliation: Kolling Institute, Northern Sydney Local Health District, and the University of Sydney at Royal North Shore Hospital, St. Leonards, New South Wales, Australia.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Little
authors.affiliation: Kolling Institute, Northern Sydney Local Health District, and the University of Sydney at Royal North Shore Hospital, St. Leonards, New South Wales, Australia.
authors.forename: James
authors.initials: J
authors.lastname: Melrose
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology*; D018450:Disease Progression; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D005346:Fibroblast Growth Factors / Q000378:metabolism; D020869:Gene Expression Profiling; D006025:Glycosaminoglycans / Q000378:metabolism; D019812:Heparan Sulfate Proteoglycans / Q000235:genetics* / Q000378:metabolism; D007150:Immunohistochemistry; D007718:Knee Injuries / Q000150:complications; D020778:Matrix Metalloproteinase 2 / Q000235:genetics; D019278:Matrix Metalloproteinase 3 / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D009929:Organ Size; D020370:Osteoarthritis, Knee / Q000209:etiology / Q000235:genetics* / Q000473:pathology; D054850:Osteophyte / Q000209:etiology / Q000235:genetics* / Q000473:pathology; D010026:Osteosclerosis / Q000209:etiology / Q000235:genetics* / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism*; D051496:Receptor, Fibroblast Growth Factor, Type 1 / Q000378:metabolism; D051498:Receptor, Fibroblast Growth Factor, Type 3 / Q000235:genetics / Q000378:metabolism; D013585:Synovitis / Q000209:etiology / Q000235:genetics* / Q000473:pathology
chemical_list: D006025:Glycosaminoglycans; D019812:Heparan Sulfate Proteoglycans; D012333:RNA, Messenger; C113569:fibroblast growth factor 18; D016222:Fibroblast Growth Factor 2; C071927:perlecan; D005346:Fibroblast Growth Factors; C496349:Fgfr1 protein, mouse; C496366:Fgfr3 protein, mouse; D051496:Receptor, Fibroblast Growth Factor, Type 1; D051498:Receptor, Fibroblast Growth Factor, Type 3; D019278:Matrix Metalloproteinase 3; C511769:Mmp3 protein, mouse; D020778:Matrix Metalloproteinase 2; C522362:Mmp2 protein, mouse