Expression and distribution of cell-surface proteoglycans in the normal Lewis rat molar periodontium

Cell-surface proteoglycans participate in several biological functions such as cell cell and cell-matrix interactions, cell adhesion, the binding to various growth factors as co-receptors and repair. To understand better the expression and distribution of cell-surface proteoglycans in the periodontal tissues, an immunohistochemical evaluation of the normal Lewis rat molar periodontium using panels of antibodies for syndecan-1, -2, -4, glypican and betaglycan was carried out. Our results demonstrated the expression and distribution of all proteoglycans in the suprabasal gingival epithelium, soft and hard connective tissues. Both cellular and matrix localization was evident within the various periodontal compartments. The presence of these cell-surface proteoglycans indicates the potential for roles in the process of tissue homeostasis, repair or regeneration in periodontium of which each function requires further study

Cell surface proteoglycan expression by human periodontal cells

Cell surface proteoglycans are known to be involved in many functions including interactions with components of the extracellular microenivironment and serve to influence cell shape, adhesion, proliferation, and differentiation. They also can act as co-receptors, to help bind and modify the action of various growth factors and cytokines. Despite their strategic location and relevance to cell function, fee studies have considered the nature of the cell surface proteoglycans associated with cells of the periodontium. Due to the structural complexity and multiplicity of cell types in the periodontium, we have selected three different cell lines (gingival connective tissue fibroblast, periodontal ligament fibroblast, and osteoblast) which each represent the unique functions within the periodontium to study the expression of cell surface proteoglycans. We hypothesized that a number of cell surface proteoglycans mill be expressed by human periodontal cells and these may be related to the source and function of the cell. Western blotting and RT-PCR methods mere used to study the expression of five cell surface proteoglycans (syndecan-1, -2, -4, glypican and betaglycan) in three cell lines of human periodontal cells in vitro. Our results demonstrated the expression of protein cores for syndecan-1 (43 kDa), syndecan-2 (48 kDa), syndecan-4 (35 kDa), glypican (64 kDa), and betaglycan (100-110 kDa). RT-PCR results confirmed that all of these cells produced mRNA for the cell surface proteoglycans under study, of which syndecan-2 showed a significant difference in expression between the periodontal ligament fibroblasts, gingival fibroblasts and osteoblasts. We conclude that the presence of specific cell surface proteoglycans on periodontal cells implies a likely role for these molecules in cell-cell, cell-matrix interactions involved in periodontal disease and/or regeneration of the periodontium, of which they may have distinctive functions related to the source and function of these cells

Differential expression and distribution of syndecan-1 and -2 in the developing periodontium of the rat

Cell surface proteoglycans are known to interact with adhesion molecules, growth factors and a variety of other effector molecules implying their central role in various aspects of cell-cell and cell-matrix interactions. To investigate the expression and distribution of the cell surface proteoglycans syndecan-1 and -2, the developing periodontal tissues of 3-, 5-, and 8-wk-old male Lewis rats, were stained by specific monoclonal antibodies against syndecan-1, or -2 core protein, using immunohistochemical techniques. The results demonstrated that syndecan-1 and -2 were expressed and distributed differentially in several compartments of the developing periodontal tissues at different ages. Expression of syndecan-1 was noted in areas of intense cellular activity such as the developing apical root tip of the tooth and at the crestal bone where new bone formation was taking place. In contrast, syndecan-2 expression and distribution did not exhibit the same patterns as syndecan-1. Syndecan-2 showed significant differences of distribution in hard tissues undergoing maturation at different ages. These findings indicate that syndecan-1 and -2 may have distinctive functions during morphogenesis, organogenesis and differentiation of the periodontium

Immunohistochemical Localization and Expression of Fibromodulin in Adult Rat Periodontium and Inflamed Human Gingiva

OBJECTIVE: The aim of this study was to determine the distribution and expression of fibromodulin in adult rat periodontal tissues and inflamed human gingiva. MATERIALS AND METHODS: The distribution of fibromodulin in rat molar periodontium and human gingival tissue was studied by immunohistochemistry. The expression of fibromodulin mRNA from human gingival fibroblasts, periodontal ligament fibroblasts and osteoblasts was studied by reverse transcription-polymerase chain reaction (RT-PCR). For comparative purposes, the distribution and mRNA expression of collagen types I and III, as well as the two small leucine-rich proteoglycans decorin and biglycan were also studied. RESULTS: In the adult rat periodontium, fibromodulin was distributed in the suprabasal gingival epithelium, gingival and periodontal fibroblasts as well as their surrounding extracellular matrices. Strong expression was noted in the palatal gingival tissues and the interfaces of the periodontal ligament with alveolar bone and cementum. In human gingival tissues, staining of fibromodulin was detected in the connective tissue of inflamed gingiva associated with both gingivitis and periodontitis; whereas, weak staining for this molecule was noted in healthy gingival tissues. The expression of mRNA for fibromodulin was strongest in the cultured osteoblasts. Periodontal ligament fibroblasts showed only a weak level of expression for fibromodulin mRNA. CONCLUSIONS: Fibromodulin is differentially expressed throughout the periodontium being primarily associated with collagen type I in non-mineralized sites. In addition fibromodulin showed an upregulation in in-flamed gingival tissue

Production of Osteopontin by Cultured Porcine Epithelial Cell Rests of Malassez

Background:  The epithelial cell rests of Malassez (ERM) are derived from Hertwig's epithelial root sheath (HERS). During development the cells of HERS deposit a variety of molecules on the newly forming root surface. The possibility that ERM retain this potential after root development is completed and secrete bone or cementum-related proteins needs to be investigated. The purpose of this study was to determine the expression of the non-collagenous proteins osteopontin (OPN) and bone sialoprotein (BSP) by cells derived from the epithelial cell rests of porcine periodontium. Methods:  ERM and fibroblasts were cultured from porcine periodontal ligament. The cells were identified and characterized using transmission electron microscopy, immunohistochemistry, western blot analysis of proteins, reverse transcription–polymerase chain reaction and ability to form mineralized nodules in culture. In particular the expression of the mineralized tissue-related proteins, BSP and OPN, was studied. Results:  Cells from porcine periodontal ligaments were successfully cultured; separated and characterized as being of either an epithelial or fibroblastic phenotype. Although the ERM did not form mineralized nodules in culture, they did express a significant amount of mRNA for OPN. Conclusion:  The results from this study provide evidence that ERM express mRNA for at least one bone/cementum-related protein. Whether this function would be consistent with a role for ERM in tissue formation, inflammation and regeneration remains to be established