Expression Patterns of Adhesion Molecules in Human Gingival Epithelium

The gingival epithelium is the physiologically important interface between the bacterially colonized gingival sulcus and periodontal soft and mineralized connective tissues requiring protection from exposure to bacteria and their products. However, the molecules comprising the gingival epithelial cell junction remain poorly characterized. Thus, the aim of the present study was to characterize the desmosome-associating proteins (desmoglein 1 and 3), desmosome-associating cytoskeleton (keratins), and tight junction-associating protein (claudin-1) within the oral gingival epithelium (OGE), sulcular epithelium (SE), and junctional epithelium (JE). Gingival epithelia excised at therapeutic flap surgery from patients with periodontitis were used to examine expression of adhesion molecules by immunofluorescence. In the OGE and SE, but not JE, desmoglein 1 was more abundant in the cell-cell contact sites of the upper than the suprabasal layer, while desmoglein 3 and desmoplakin were present in the cell-cell contact sites in all layers of the JE as well as the OGE and SE. Keratin 14 and 19, but not keratin 13 and 4, were present in the JE. Claudin-1 was expressed only in the intermediate layers in the uppermost flat layers in the OGE. These data indicated that the JE contained only few desmosomes composed of desmoglein 3. Thus, it is thought that the anchoring junction connecting JE cells is not firm, causing widened intercellular spaces in the JE. In contrast, the OGE, which has tight junctions, functions as a barrier.