title: Role of toll-like receptors in human iris pigment epithelial cells and their response to pathogen-associated molecular patterns.
abstract: BACKGROUND
  Toll-like receptor (TLR) activation is hypothesized to contribute to inflammatory eye disease including uveitis, yet the distribution pattern of TLRs in human uveal tissues remains poorly described. The purpose of this study was to investigate the expression profile of TLRs in human iris pigment epithelial cells (IPE) at the gene and protein level and examine the effect of pathogen-associated molecular patterns (PAMPs), such as Pam3CSK4.3HCl, Poly(I:C), lipopolysaccharides (LPS from E. coli serotype O111:B4), Flagellin, MALP-2 (macrophage activating lipopeptide-2), Poly(U) and CpGODN2395 on the production of inflammatory mediators including interleukin-8 (IL-8) and monocyte chemotactic protein 1 (MCP-1) from human IPE and retinal pigment epithelial cells (RPE).
  
  
  METHODS
  RT-PCR and Western blotting was employed to investigate the expression of TLRs 1-10 in primary IPE and RPE. Secretion of IL-8 or MCP-1 following treatment with PAMPs was measured by ELISA. The role of TLR2, TLR3 and TLR4 in mediating an inflammatory response was investigated using pharmacological TLR inhibitors.
  
  
  RESULTS
  IPE and RPE expressed transcripts for TLR1-6 and 8-10; and proteins for TLR1-6 and 9. IPE secreted IL-8 or MCP-1 in response to Pam3CSK4.3HCl, Poly(I:C), LPS and MALP-2, whereas RPE produced IL-8 only after Poly(I:C), LPS or MALP-2 treatment. TLR inhibitors (OxPAPC, CI-095 and chloroquine) blocked IL-8 secretion in Poly(I:C), LPS or MALP-2-treated IPE and RPE.
  
  
  CONCLUSIONS
  Ocular pigment epithelial cells respond to PAMPs through activation of TLRs, particularly TLR2, TLR3 and TLR4. Expression of TLRs in human IPE cells provides a basis for responses to many ocular pathogens and their activation may be involved in the pathogenesis of ocular inflammation.
authors.affiliation: Inflammation and Infection Research Centre, Department of Pathology, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, Australia.
authors.forename: Kelly
authors.initials: K
authors.lastname: Mai
authors.affiliation: Inflammation and Infection Research Centre, Department of Pathology, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, Australia ; Department of Ophthalmology, Prince of Wales Hospital, Randwick, NSW, Australia.
authors.forename: Jeanie Jy
authors.initials: JJ
authors.lastname: Chui
authors.affiliation: Inflammation and Infection Research Centre, Department of Pathology, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, Australia.
authors.forename: Nick
authors.initials: N
authors.lastname: Di Girolamo
authors.affiliation: Save Sight Institute, Sydney Eye Hospital, University of Sydney, Sydney, Australia.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: McCluskey
authors.affiliation: Inflammation and Infection Research Centre, Department of Pathology, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, Australia ; UNSW Medicine, University of New South Wales, Sydney, Australia.
authors.forename: Denis
authors.initials: D
authors.lastname: Wakefield
keywords: IPE; Immunology; PAMPs; TLR; Uveitis
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