Cytokine regulation of syndecan-1 and -2 gene expression in human periodontal fibroblasts and osteoblasts

Wilairat Worapamorn, D. of Conservative Dentistry, F. of Dentistry, PSU.
Tam, S.P., D. of of Physiology and Pharmacology, The U. of Queensland, Australia
Li, H., Connective Tissue Research Lab, D. of Dentistry, The U. of Queensland, Australia
Haase, H.R., Connective Tissue Research Lab, D. of Dentistry, The U. of Queensland, Australia
Bartold, P.M., Prof., D. of Dentistry, The U. of Queensland, Australia
Corresponding e-mail : wwilaira@ratree.psu.ac.th

Presented : 24th Annual Scientific Conference/Matrix Biology, South Stradbroke Island, Queensland, Australia, 28 September - 1 October 2000
Key words : syndecan-1, syndecan-2, growth factors/cytokines, periodontal fibroblasts, osteoblasts

The cell-surface proteoglycans, syndecan-1 and -2, participate in several biological func- tions including interactions with components of the extracellular microenvironment, and act as coreceptors, which bind and modify the action of various growth factors and cytokines. Regulation of syndecan-1 and -2 gene expression was investigated in human periodontal ligament fibroblasts (PDLF), osteoblasts (OB) and gingival fibroblasts (GF), in response to platelet-derived growth factor (PDGF-BB), transforming growth factor (TGF-b1), and interleukin (IL-1b1) by Northern blot analyses. We also compared the effect of PDGF-BB and TGF-b1, separately and in combination, in the prolonged presence of IL-1b on the expression of both syndecan genes. The results demons- trated that the three cell lines regulated the expression of syndecan-1 and -2 in response to growth factors and cytokines in different manners. These cell lines increased syndecan-1 mRNA levels in response to either PDGF-BB or TGF-b1 and decreased in response to IL-1b. The effect of IL-1b on syndecan-1 mRNA synthesis was reversed after adding PDGF-BB and TGF-b1, separately or in combination, in the presence of IL-1b1. In contrast, syndecan-2 mRNA level was markedly up-regulated in response to either TGF-b1 or IL-1b in OB when compared with the other two cell lines. However, the stimulatory effect of TGF-b1 on syndecan-2 mRNA production in OB was abolished in the prolonged presence of IL-1b. The present study demonstrates that the gene expres-sion of syndecan-1 and -2 is differentially regulated by growth factors and cytokines in human periodontal cells and lends support to the distinct functions of the two syndecans which correlate to the sources and functions of the cells of the periodontium.
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