IADR Abstract Archives
Mesenchymal regulation of the Junctional Epithelium
Objectives: Epithelial-mesenchymal interactions may play an important role in the development and maintenance of the dentogingival junction (DGJ). Previously, we identified Sca1 as a key marker which differentiate fibroblast subsets from the superficial connective tissues (SCT, gingival fibroblasts) and deep connective tissues (DCT, periodontal ligament fibroblasts). We hypothesise that fibroblasts from the SCT promote epithelial growth and differentiation whilst those from DCT result in an undifferentiated, immature epithelium similar to the junctional epithelium (JE) phenotype.
Methods: 3D Organotypic constructs consisted of an epithelium overlying a connective tissue equivalent. These constructs were made by seeding 1) human periodontal ligament fibroblasts (HPDLF) or 2) human gingival fibroblasts (HGF) into collagen gels. After contraction, the gels were seeded with H400 epithelial cells. Formalin fixed paraffin embedded sections were prepared from the 3-D cultures. Epithelial phenotype was characterised via immunohistochemistry for the expression of Keratins 1, 8, 10, 18, and 19.
Results: Organotypic constructs from HGF consistently resulted in the formation of a multilayered epithelium characterised by keratin 1, 8, 10, 18, 19; whereas HPDLF constructs resulted in a monolayered epithelium with little sign of growth or proliferation and showing a particular absence for the expression of Keratin 10.
Conclusions: Fibroblast subsets have different influences on the epithelium, with SCT supporting gingival growth and differentiation and DCT preventing epithelial growth and differentiation. The findings are consistent with the hypothesis that the DCT regulates an epithelium similar to the JE phenotype and furthermore supports the role of specific fibroblast populations in the regulation of the gingival and junctional epithelial phenotypes. A dysregulation of the epithelial-mesenchymal signalling in the dentogingival junction may account for the apical migration of this tissue during periodontitis.
Methods: 3D Organotypic constructs consisted of an epithelium overlying a connective tissue equivalent. These constructs were made by seeding 1) human periodontal ligament fibroblasts (HPDLF) or 2) human gingival fibroblasts (HGF) into collagen gels. After contraction, the gels were seeded with H400 epithelial cells. Formalin fixed paraffin embedded sections were prepared from the 3-D cultures. Epithelial phenotype was characterised via immunohistochemistry for the expression of Keratins 1, 8, 10, 18, and 19.
Results: Organotypic constructs from HGF consistently resulted in the formation of a multilayered epithelium characterised by keratin 1, 8, 10, 18, 19; whereas HPDLF constructs resulted in a monolayered epithelium with little sign of growth or proliferation and showing a particular absence for the expression of Keratin 10.
Conclusions: Fibroblast subsets have different influences on the epithelium, with SCT supporting gingival growth and differentiation and DCT preventing epithelial growth and differentiation. The findings are consistent with the hypothesis that the DCT regulates an epithelium similar to the JE phenotype and furthermore supports the role of specific fibroblast populations in the regulation of the gingival and junctional epithelial phenotypes. A dysregulation of the epithelial-mesenchymal signalling in the dentogingival junction may account for the apical migration of this tissue during periodontitis.