title: Retinoic acid-inducible gene 1-like receptors in the upper respiratory tract.
abstract: BACKGROUND
  Retinoic acid-inducible gene 1-like receptors (RLRs) are a novel family of pattern recognition receptors that include retinoic acid-inducible gene 1 (RIG-1), melanoma differentiation-associated gene 5 (MDA-5), and laboratory of genomics and  physiology 2 (LGP-2). The knowledge of RLRs and their function in the human airway is limited. This study explores the role of RLRs in the upper respiratory tract.
  
  
  METHODS
  Tonsils, adenoids, nasal polyps, and biopsy specimens from the nasal mucosa were examined for the  occurrence of the RIG-1, MDA-5, and LGP-2 using real-time reverse-transcription polymerase chain reaction and immunohistochemistry. The nasopharyngeal epithelial cell line FaDu was cultured with the RIG-1/MDA-5 ligand poly(I:C)/LyoVec (Invivogen, San Diego, CA) and analyzed for cytokine release  using ELISA.
  
  
  RESULTS
  RIG-1, MDA-5, and LGP-2 mRNA were found in all tissues tested. The airway epithelium appeared to be their most prominent location. The RIG-1 and MDA-5 mRNA levels were higher in nasal polyps than in normal nasal mucosa, a state that seemed to be reversed  by local steroid treatment. Culture of FaDu with poly(I:C)/LyoVec resulted in IL-6 and IL-8 release. No alteration in RLR expression in tonsils was seen on infection.
  
  
  CONCLUSIONS
  This study shows the presence and functional activity of RLRs in the human upper airways. It  also suggests a role for RLRs in nasal polyposis.
authors.affiliation: Laboratory of Clinical and Experimental Allergy Research, Department of Otorhinolaryngology, Skåne University Hospital, Lund University, Malmö, Sweden.
authors.forename: Jesper
authors.initials: J
authors.lastname: Bogefors
authors.forename: Anne Månsson
authors.initials: AM
authors.lastname: Kvarnhammar
authors.forename: Leith
authors.initials: L
authors.lastname: Latif
authors.forename: Terese
authors.initials: T
authors.lastname: Petterson
authors.forename: Rolf
authors.initials: R
authors.lastname: Uddman
authors.forename: Lars Olaf
authors.initials: LO
authors.lastname: Cardell
mesh_terms: D000234:Adenoids / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002460:Cell Line; D002648:Child; D002675:Child, Preschool; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D000072640:Interferon-Induced Helicase, IFIH1; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D009298:Nasal Polyps / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D014066:Palatine Tonsil / Q000473:pathology; D011070:Poly I-C / Q000494:pharmacology; D020365:RNA Helicases / Q000235:genetics / Q000378:metabolism*; D011971:Receptors, Immunologic; D051192:Receptors, Pattern Recognition / Q000235:genetics / Q000378:metabolism*; D055815:Young Adult
chemical_list: D015850:Interleukin-6; D016209:Interleukin-8; D011971:Receptors, Immunologic; D051192:Receptors, Pattern Recognition; C520569:DHX58 protein, human; C452820:RIGI protein, human; C452815:IFIH1 protein, human; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases; D000072640:Interferon-Induced Helicase, IFIH1; D020365:RNA Helicases; D011070:Poly I-C