Interaction of oral bacteria with gingival epithelial cell multilayers

Area of Science:

• Oral microbiology
• Epithelial biology
• Periodontal disease research

Background:

• Gingival epithelial cells form a barrier against oral bacteria.
• Understanding host-pathogen interactions is crucial for periodontal disease research.
• Junctional epithelium plays a key role in oral health.

Purpose of the Study:

• To model human junctional epithelium interactions with oral bacteria.
• To investigate bacterial invasion and host responses.
• To differentiate interactions of pathogenic vs. commensal bacteria.

Main Methods:

• Primary gingival epithelial cells cultured as multilayers at an air-liquid interface.
• Infection with labeled Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, and Streptococcus gordonii.
• Confocal microscopy, image analysis, transepithelial electrical resistance, cytokine assays, and apoptosis assays.

Main Results:

• P. gingivalis invaded cells and spread intercellularly.
• A. actinomycetemcomitans and F. nucleatum showed extracellular intercellular movement.
• S. gordonii remained extracellular on the superficial layer.
• Pathogenic bacteria induced inflammatory cytokine secretion (IL-1β, TNF-α, IL-6, IL-8) and apoptosis.
• P. gingivalis did not elicit significant cytokine secretion or apoptosis.
• No bacterial species disrupted epithelial barrier function.

Conclusions:

• Pathogenic oral bacteria can traverse the epithelial barrier.
• Commensal bacteria do not invade the epithelium.
• Distinct host responses characterize interactions with different oral bacteria.
• This model differentiates pathogenic and commensal bacterial behaviors and host responses.