P2‐47: Double stranded RNA induces vulnerability of airway epithelial barrier integrity by influencing airway basal cells

mice are resistant to pneumococcal pneumonia compared with their wild-type control. In contrast, chronic periodontitis, a chronic inflammatory disease caused by the infection of periodontopathic bacteria, typically Porphyromonas gingivalis, is one of the most prevalent microbial diseases affecting humans globally. Although chronic periodontitis has been identified as a pneumonia risk factor, how periodontopathic bacteria cause pneumonia is not known. Results: We found that S. pneumoniae adhered to PAFR expressed on A549 human alveolar epithelial cells stimulated by P. gingivalis culture supernatant, and this was abrogated by a PAFR-specific inhibitor. Among the major virulence factors of P. gingivalis [lipopolysaccharide (LPS), fimbriae and gingipains (Rgps and Kgp)], PAFR expression and pneumococcal adhesion were executed in an Rgpdependent manner. LPS and fimbriae did not induce PAFR expression. Conclusion: Our results uncovered a novel mechanism by which P. gingivalis induces pneumococcal adhesion to lungderived epithelial cells and suggest that this interaction may contribute to an increased risk of pneumococcal pneumonia in the context of periodontal disease.