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

Abstract

Cell-surface proteoglycans participate in several biological functions including interactions with a variety of 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-beta 1), and interleukin (IL-1 beta) by Northern blot analyses. We also compared the effect of PDGF-BB and TGF-beta 1, separately and in combination, in the prolonged presence of IL-1 beta on the expression of both syndecan genes. The results demonstrated 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-beta 1 and decreased levels in response to IL-1 beta. The effect of IL-1 beta on syndecan-1 mRNA synthesis was partially reversed after adding PDGF-BB and TGF-beta 1, separately or in combination, in the presence of IL-1 beta. In contrast, syndecan-2 mRNA level was markedly upregulated in response to either TGF-beta 1 or IL-1 beta in OB when compared with the other two cell lines. However, the stimulatory effect of TGF-beta 1 on syndecan-2 mRNA production in OB was abolished in the prolonged presence of IL-1 beta. These findings lend support to the notion that syndecan-1 and syndecan-2 have distinct functions which correlate with their source and functions within the periodontium.