Interaction of oral bacteria with gingival epithelial cell multilayers

Abstract

Primary gingival epithelial cells were cultured in multilayers as a model for the study of interactions with oral bacteria associated with health and periodontal disease. Multilayers maintained at an air-liquid interface in low calcium medium displayed differentiation and cytokeratin properties characteristic of junctional epithelium. Multilayers were infected with fluorescently labeled Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum or Streptococcus gordonii, and bacterial association was determined by confocal microscopy and quantitative image analysis. P. gingivalis invaded intracellularly and spread cell to cell. A. actinomycetemcomitans and F. nucleatum remained extracellular and showed intercellular movement through the multilayer. S. gordonii remained extracellular and predominantly associated with the superficial cell layer. None of the bacterial species disrupted barrier function as measured by transepithelial electrical resistance. P. gingivalis did not elicit secretion of proinflammatory cytokines. However, A. actinomycetemcomitans and S. gordonii induced IL-1β, TNF-α, IL-6 and IL-8 secretion; and F. nucleatum stimulated production of IL-1β and TNF-α. A. actinomycetemcomitans, F. nucleatum and S. gordonii, but not P. gingivalis, increased levels of apoptosis after 24 h infection. The results indicate that the organisms with pathogenic potential were able to traverse the epithelium, while the commensal bacteria did not. In addition, distinct host responses characterized the interaction between the junctional epithelium and oral bacteria.

Synergistic Interaction between Candida albicans and Commensal Oral Streptococci in a Novel In Vitro Mucosal Model

“…The images were manually quantified. As a positive control for the induction of apoptosis, we inoculated the oral mucosal model with F. nucleatum ATCC 10953, followed by incubation under static conditions in an anaerobic chamber for 16 h, since these conditions are known to trigger high levels of apoptotic cell death in 3-D tissue constructs (2,17). The results were expressed as the percentage of caspase-3-positive epithelial cells from the total number of epithelial nuclei quantified in the same image.…”

Aggregatibacter actinomycetemcomitans Infection Enhances Apoptosis In Vivo through a Caspase-3-Dependent Mechanism in Experimental Periodontitis

“…It has been suggested that apoptosis of epithelial cells may contribute to the loss of epithelial barrier function (6). Moreover, loss of gingival fibroblasts has been shown to be one of the largest cellular changes that occurs with periodontal disease progression and may be associated with a loss of connective tissue attachment (29,43).…”

Neutrophils alter epithelial response to Porphyromonas gingivalis in a gingival crevice model.

“…To increase relevance, a multilayer epithelial cell model has been established with which to observe P. gingivalis-host interactions (Dickinson et al, 2011). We have recently described a gingival crevice model in which primary human neutrophils can protect human gingival epithelial cells (HGEC) from P.…”