Cytokine responses of oral epithelial cells exposed to Porphyromonas gingivalis
Nejat Düzgüneş: 0000-0001-6159-1391
39th Annual Meeting of the American Association for Dental Research (AADR)
March 3-6, 2010
Date of Presentation
Journal of Dental Research
Journal Volume Number
89 (Special issue A)
Objectives: The periodontopathogen Porphyromonas gingivalis (Pg) adheres to, invades and replicates within human oral epithelial cells. The pro-inflammatory cytokine interleukin-8 (IL-8) is a potent chemoattractant inducing the influx of neutrophils into periodontal lesions. We quantified the IL-8 secreted by human oral squamous HSC-3 cells after exposure to live and heat-inactivated Pg, and to lipopolysaccharide (LPS) from Pg and E. coli. Methods: The Pg strain 2561 (ATCC 33277) was sub-cultivated on blood agar plates and suspended in Medium 199 (4x108 Pg/ml). HSC-3 cells were challenged with live or heat-killed Pg at 107 or 108 bacteria/well, and incubated at 37°C for 6, 24 and 48 h. The Multi-Analyte Profiler ELISArray kit was used to profile pro-inflammatory cytokines and chemokines. IL-8 was determined by ELISA. LPS from E. coli and Pg were tested at 5 µg/ml. Results: Analysis by the Profiler ELISA indicated the stimulation of IL-6 and IL-8. Secretion of IL-8 was affected by the number and heat killing of bacteria, and the time of incubation. Untreated HSC-3 cells produced 5.2±0.9 ng IL-8/ml within 24 h, while cells incubated with 107 and 108 live Pg secreted 9.6±2.3 and 12.9±2.8 ng IL-8/ml, respectively. Cells stimulated with heat-killed Pg produced higher levels of IL-8: 12.0±2.1 and 18.1±1.9 ng IL-8/ml. Higher IL-8 stimulation by heat-killed Pg was also evident at 48 h. Treatment with LPS from Pg and E. coli at 5 µg/ml resulted in the production of 11.8±6.1 and 8.6±3.2 ng IL-8/ml, respectively in 24 h. Conclusion: Pg induced significant IL-8 secretion by HSC-3 cells. Degradation of IL-8 by cysteine proteinases (gingipains) produced by live Pg may be responsible for the higher up-regulation of IL-8 observed with heat-killed bacteria. Supported by Research Pilot Project Award 03-Activity 069 from the University of the Pacific, School of Dentistry (K. Konopka).
Cytokine responses of oral epithelial cells exposed to Porphyromonas gingivalis.
Paper presented at 39th Annual Meeting of the American Association for Dental Research (AADR) in Washington, DC.