title: Staphylococcus aureus impairs the airway epithelial barrier in vitro.
abstract: BACKGROUND
  Chronic rhinosinusitis (CRS) is a cluster of disorders that result in sinonasal mucosal inflammation. Staphylococcus aureus (S. aureus) is associated with severe and recalcitrant CRS. The purpose of our study was to investigate the effect of S. aureus on respiratory epithelial barrier structure and function.
  
  
  METHODS
  Conditioned media from S. aureus reference strains (American Type Culture Collection [ATCC] 13565, 14458, and 25923) was applied to air-liquid interface (ALI) cultures of primary human nasal epithelial cells (HNECs) and transepithelial electrical resistance (TEER) was measured to assess cell-to-cell integrity. Electron microscopy was used to gauge the ciliated area and tight junctions (TJs). Additionally, the expression of the TJ protein zona occludens-1 (ZO-1) was examined via immunofluorescence. Statistical analysis was performed using analysis of variance (ANOVA) with pairwise Bonferroni-adjusted t tests.
  
  
  RESULTS
  Secreted products applied to ALI cultures from S. aureus strain 13565 caused a concentration-dependent decline in electrical impedance compared to controls and reference strains 14458 and 25923 (p < 0.001). Electron microscopy showed a distinct separation between adjacent cells apically, in the region of TJs. The ciliated area was not affected; however, ZO-1 expression became discontinuous in HNECs exposed to the 13565 strain's conditioned media.
  
  
  CONCLUSIONS
  Conditioned media of the S. aureus strain 13565 damages the airway epithelium by disrupting the TJs between primary HNECs grown at an ALI. These findings suggest that strain-specific S. aureus-secreted product(s) compromise epithelial barrier function, which may constitute 1 of the roles played by S. aureus in the pathophysiology of recalcitrant CRS. Further research is required to uncover the relevant molecular mechanisms.
authors.affiliation: Department of Surgery-Otorhinolaryngology Head and Neck Surgery, The Queen Elizabeth Hospital and the University of Adelaide, Adelaide, SA, Australia.
authors.forename: Zacki
authors.initials: Z
authors.lastname: Malik
authors.affiliation: Department of Surgery-Otorhinolaryngology Head and Neck Surgery, The Queen Elizabeth Hospital and the University of Adelaide, Adelaide, SA, Australia.
authors.forename: Eugene
authors.initials: E
authors.lastname: Roscioli
authors.affiliation: Department of Surgery-Otorhinolaryngology Head and Neck Surgery, The Queen Elizabeth Hospital and the University of Adelaide, Adelaide, SA, Australia.
authors.forename: Jae
authors.initials: J
authors.lastname: Murphy
authors.affiliation: Department of Surgery-Otorhinolaryngology Head and Neck Surgery, The Queen Elizabeth Hospital and the University of Adelaide, Adelaide, SA, Australia.
authors.forename: Judy
authors.initials: J
authors.lastname: Ou
authors.affiliation: Department of Surgery-Otorhinolaryngology Head and Neck Surgery, The Queen Elizabeth Hospital and the University of Adelaide, Adelaide, SA, Australia.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Bassiouni
authors.affiliation: Department of Surgery-Otorhinolaryngology Head and Neck Surgery, The Queen Elizabeth Hospital and the University of Adelaide, Adelaide, SA, Australia.
authors.forename: Peter-John
authors.initials: PJ
authors.lastname: Wormald
authors.affiliation: Department of Surgery-Otorhinolaryngology Head and Neck Surgery, The Queen Elizabeth Hospital and the University of Adelaide, Adelaide, SA, Australia.
authors.forename: Sarah
authors.initials: S
authors.lastname: Vreugde
mesh_terms: D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D017097:Electric Impedance; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007365:Intercellular Junctions / Q000378:metabolism*; D008854:Microscopy, Electron; D009296:Nasal Cavity / Q000166:cytology; D009297:Nasal Mucosa / Q000378:metabolism* / Q000382:microbiology* / Q000473:pathology; D013211:Staphylococcus aureus / Q000502:physiology*; D019108:Tight Junctions; D062826:Zonula Occludens-1 Protein / Q000378:metabolism
chemical_list: D017077:Culture Media, Conditioned; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein
keywords: air-liquid interface; chronic rhinosinusitis; electric impedance; epithelium; tight junctions