title: Differential expression of TLR-2 and TLR-4 in the epithelial cells in oral lichen planus.
abstract: OBJECTIVE
  Oral lichen planus (OLP) is a chronic inflammatory condition of the mucosa mediated by a complex signalling network between the keratinocytes and the sub-epithelial lymphocytes. Since OLP occurs in constantly renewing epithelium continuously exposed to commensals, we hypothesised that the epithelial cell microflora interactions may mediate the persistent inflammation. By virtue of their ability to respond to most oral commensal microorganisms, the toll like receptor-2 (TLR-2) and TLR-4 are the most widely investigated receptors in oral diseases. The overall objective of this study was to investigate the role of TLR-2 and TLR-4 in OLP.
  
  
  METHODS
  Systemically healthy OLP and control subjects were recruited after obtaining the institutional review board approval. Expression of TLR-2 and TLR-4 proteins and transcripts in the tissue epithelium and in the epithelial cells isolated from saliva were determined by immunohistochemistry and quantitative real-time polymerase chain reaction respectively.
  
  
  RESULTS
  The tissue epithelium and the salivary epithelial cells expressed reduced TLR-2 and increased TLR-4 proteins and transcripts in OLP. The salivary epithelial cells from OLP subjects secreted elevated IL-12. However, upon stimulation with bacterial lipopolysaccharide the epithelial cells from OLP exhibited a mixed Th1 (IL-12) and Th2 (IL-4) response. Presence of dexamethasone significantly reduced inflammatory cytokines in the in vitro stimulated cultures of salivary epithelial cells from OLP subjects.
  
  
  CONCLUSIONS
  Collectively, our data support a critical role for the host-microbial interactions in the OLP pathogenesis. The potential use of exfoliated oral epithelial cells in saliva for functional analysis exponentially increases its value as biological specimen for clinical research.
authors: Department of Oral Pathology, Medicine and Radiology, Indiana University School of Dentistry, Indianapolis, IN 46202-5186, United States.
authors: Srihari B
authors: SB
authors: Janardhanam
authors: Sivaraman
authors: S
authors: Prakasam
authors: Venkatesh T
authors: VT
authors: Swaminathan
authors: Krithika N
authors: KN
authors: Kodumudi
authors: Susan L
authors: SL
authors: Zunt
authors: Mythily
authors: M
authors: Srinivasan
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D003907:Dexamethasone / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D018664:Interleukin-12 / Q000378:metabolism; D017676:Lichen Planus, Oral / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D010784:Photomicrography; D060888:Real-Time Polymerase Chain Reaction; D012463:Saliva / Q000166:cytology; D051195:Toll-Like Receptor 2 / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D008070:Lipopolysaccharides; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D018664:Interleukin-12; D003907:Dexamethasone