title: Staphylococcus aureus biofilms induce apoptosis and expression of interferon-γ, interleukin-10, and interleukin-17A on human sinonasal explants.
abstract: BACKGROUND
  Staphylococcus aureus is one of the most common bacteria associated with chronic rhinosinusitis (CRS). Although S. aureus biofilms have been correlated with disease severity in CRS, little is known about the initial immune response that biofilms induce in the sinonasal mucosa.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the innate immune response (in terms of cytokines) of nondiseased human sinonasal tissue to S. aureus biofilms.
  
  
  METHODS
  Full-thickness sinonasal explant cultures (n = 7 donors) were challenged with established S. aureus biofilms for 24 hours. The expression profiles of 17 cytokines were measured using multiplex analysis, real-time quantitative reverse transcription polymerase chain reaction, and immunohistochemistry. Differences in expression were evaluated using Student's t-test.
  
  
  RESULTS
  Interleukin (IL)-1β, IL-10, TNF, IL-17A, and interferon (IFN)-γ were up-regulated at the RNA and protein levels in biofilm-treated tissues compared with controls. Elevation of caspase-3 in biofilm-treated samples indicates S. aureus biofilms induce apoptosis on the sinonasal mucosa.
  
  
  CONCLUSIONS
  S. aureus biofilms induced apoptosis and a predominant proinflammatory immune response on normal sinonasal mucosal explants. This immune response appeared to be triggered by intrinsic bacterial elements but also by components of the biofilm matrix. Live biofilms were present on the mucosa at the end of the challenge, suggesting an inability of the induced immune response to eliminate the S. aureus biofilms.
authors.affiliation: Department of Surgery, Otorhinolaryngology Head and Neck Surgery, The Queen Elizabeth Hospital, and the University of Adelaide, Adelaide, South Australia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Cantero
authors.forename: Clare
authors.initials: C
authors.lastname: Cooksley
authors.forename: Ahmed
authors.initials: A
authors.lastname: Bassiouni
authors.forename: Hai Bac
authors.initials: HB
authors.lastname: Tran
authors.forename: Eugene
authors.initials: E
authors.lastname: Roscioli
authors.forename: Peter-John
authors.initials: PJ
authors.lastname: Wormald
authors.forename: Sarah
authors.initials: S
authors.lastname: Vreugde
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis; D018441:Biofilms; D053148:Caspase 3 / Q000378:metabolism; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis*; D016753:Interleukin-10 / Q000032:analysis*; D020381:Interleukin-17 / Q000032:analysis*; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009297:Nasal Mucosa / Q000276:immunology / Q000382:microbiology; D010256:Paranasal Sinuses / Q000276:immunology* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000502:physiology*; D018417:Th1 Cells / Q000276:immunology; D058504:Th17 Cells / Q000276:immunology
chemical_list: C508609:IL10 protein, human; C508717:IL17A protein, human; D020381:Interleukin-17; D016753:Interleukin-10; D007371:Interferon-gamma; D053148:Caspase 3