Moraxella catarrhalis decreases antiviral innate immune responses by down‐regulation of TLR3 via inhibition of p53 in human bronchial epithelial cells

• DOI: 10.1096/fj.201500172r
• Publication Date: 2016-03-16T03:54:13Z
• Authors: Annina Heinrich; Helge Haarmann; Sabrina Zahradnik; Katrin Frenzel; Frauke Schreiber; Tilman E. Klassert; Kerstin A. Heyl; Anne‐Sophie Endres; Michaela Schmidtke; Jörg Hofmann; Hortense Slevogt
• Keywords: TLR3; Moraxella (Branhamella) catarrhalis; Rhinovirus

Chronic obstructive pulmonary disease (COPD) is complicated by infectious exacerbations with acute worsening of respiratory symptoms. Coinfections bacterial and viral pathogens are associated more severe exacerbations. Moraxella catarrhalis one the most frequent lower tract detected in COPD. We therefore studied impact M. on antiviral innate immune response that mediated via TLR3 p53. Molecular interactions between normal human bronchial epithelial (NHBE) cells as well Beas-2B were using flow cytometry, quantitative PCR analysis, chromatin immunoprecipitation, RNA interference, ELISA. induces a significant down-regulation cells. In catarrhalis-infected cells, expression p53 was decreased. reduced binding to tlr3 promoter, resulting gene transcription. diminished TLR3-dependent secretion IFN-β, IFN-λ, chemokine (C-X-C motif) ligand 8. addition infected rhinovirus type 1A increased compared uninfected reduces defense functions which may increase susceptibility infections.-Heinrich, A., Haarmann, H., Zahradnik, S., Frenzel, K., Schreiber, F., Klassert, T. E., Heyl, K. Endres, A.-S., Schmidtke, M., Hofmann, J., Slevogt, H. decreases responses inhibition