CTGF/Hcs24, hypertrophic chondrocyte-specific gene product, interacts with perlecan in regulating the proliferation and differentiation of chondrocytes.
Connective tissue growth factor/hypertrophic chondrocyte-specific gene product 24 (CTGF/Hcs24) plays important roles in the control of the proliferation and differentiation of chondrocytes in vitro. To clarify the mechanisms of regulation by CTGF/Hcs24 with respect to cartilage metabolism, we investigated the interaction between CTGF/Hcs24 and heparan sulfate proteoglycan perlecan. An immunofluorescence study showed that CTGF/Hcs24 was colocalized with heparan sulfate and perlecan in human chondrosarcoma-derived chondrocytic cell line HCS-2/8 in vitro. Northern blot analysis showed that perlecan, syndecan-1, -2, and -4 transcripts were detected in HCS-2/8 cells. Particularly, expression of the perlecan gene increased markedly in HCS-2/8 cells by recombinant CTGF/Hcs24 (rCTGF/Hcs24) treatment. We also found that CTGF/Hcs24 interacted with perlecan from HCS-2/8 cells in vitro. Furthermore, CTGF/Hcs24-stimulated gene expression of the aggrecan gene, as well as DNA/proteoglycan synthesis, was diminished when HCS-2/8 cells were pretreated with heparinase, indicating that the effects of CTGF/Hcs24 on chondrocytes occurred through the interaction between CTGF/Hcs24 and heparan sulfate on the cells. An in vivo study using mouse growth plate revealed that CTGF/Hcs24 produced by hypertrophic chondrocytes was localized from the proliferative to the hypertrophic zone, whereas perlecan was predominantly localized in the prehyphertrophic zone. Consistent with such findings in vivo, the binding of (125)I-rCTGF/Hcs24 to maturing chondrocytes was at higher levels than that to chondrocytes in hypertrophic stages. These findings suggest that CTGF/Hcs24 produced in the hypertrophic region may act on chondrocytes in the proliferative and maturative zone via some heparan sulfate proteoglycan, such as perlecan.
Nishida
Takashi
T
Department of Biochemistry and Molecular Dentistry, Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan.
Kubota
Satoshi
S
Fukunaga
Tomohiro
T
Kondo
Seiji
S
Yosimichi
Gen
G
Nakanishi
Tohru
T
Takano-Yamamoto
Teruko
T
Takigawa
Masaharu
M
D000368:Aged; D000818:Animals; D015152:Blotting, Northern; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D019902:Chondrocytes / Q000166:cytology*; D055513:Connective Tissue Growth Factor; D019812:Heparan Sulfate Proteoglycans / Q000502:physiology*; D019763:Heparin Lyase / Q000494:pharmacology; D006801:Humans; D017874:Immediate-Early Proteins / Q000502:physiology*; D007158:Immunologic Techniques; D036341:Intercellular Signaling Peptides and Proteins / Q000502:physiology*; D008024:Ligands; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D011994:Recombinant Proteins / Q000378:metabolism; D014407:Tumor Cells, Cultured
C526317:CCN2 protein, human; C526318:CCN2 protein, mouse; D019812:Heparan Sulfate Proteoglycans; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D011994:Recombinant Proteins; D055513:Connective Tissue Growth Factor; C071927:perlecan; D019763:Heparin Lyase