title: Microarray analysis of gene expression in West Nile virus-infected human retinal pigment epithelium.
abstract: OBJECTIVE
  To identify key genes differentially expressed in the human retinal pigment epithelium (hRPE) following low-level West Nile virus (WNV) infection.
  
  
  METHODS
  Primary hRPE and retinal pigment epithelium cell line (ARPE-19) cells were infected with WNV (multiplicity of infection 1). RNA extracted from mock-infected and WNV-infected cells was assessed for differential expression of genes using Affymetrix microarray. Quantitative real-time PCR analysis of 23 genes was used to validate the microarray results.
  
  
  RESULTS
  Functional annotation clustering of the microarray data showed that gene clusters involved in immune and antiviral responses ranked highly, involving genes such as chemokine (C-C motif) ligand 2 (CCL2), chemokine (C-C motif) ligand 5 (CCL5), chemokine (C-X-C motif) ligand 10 (CXCL10), and toll like receptor 3 (TLR3). In conjunction with the quantitative real-time PCR analysis, other novel genes regulated by WNV infection included indoleamine 2,3-dioxygenase (IDO1), genes involved in the transforming growth factor-β pathway (bone morphogenetic protein and activin membrane-bound inhibitor homolog [BAMBI] and activating transcription factor 3 [ATF3]), and genes involved in apoptosis (tumor necrosis factor receptor superfamily, member 10d [TNFRSF10D]). WNV-infected RPE did not produce any interferon-γ, suggesting that IDO1 is induced by other soluble factors, by the virus alone, or both.
  
  
  CONCLUSIONS
  Low-level WNV infection of hRPE cells induced expression of genes that are typically associated with the host cell response to virus infection. We also identified other genes, including IDO1 and BAMBI, that may influence the RPE and therefore outer blood-retinal barrier integrity during ocular infection and inflammation, or are associated with degeneration, as seen for example in aging.
authors.affiliation: Discipline of Pathology, Bosch Institute, School of Medical Sciences, Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
authors.forename: Luis
authors.initials: L
authors.lastname: Munoz-Erazo
authors.forename: Ricardo
authors.initials: R
authors.lastname: Natoli
authors.forename: Jan Marie
authors.initials: JM
authors.lastname: Provis
authors.forename: Michelle Catherine
authors.initials: MC
authors.lastname: Madigan
authors.forename: Nicholas Jonathan Cole
authors.initials: NJ
authors.lastname: King
mesh_terms: D017209:Apoptosis / Q000235:genetics / Q000276:immunology; D018925:Chemokines / Q000235:genetics / Q000276:immunology; D004847:Epithelial Cells / Q000166:cytology / Q000276:immunology* / Q000821:virology; D015870:Gene Expression / Q000276:immunology*; D020869:Gene Expression Profiling; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology; D005810:Multigene Family; D020411:Oligonucleotide Array Sequence Analysis; D061251:Primary Cell Culture; D040901:Proteomics; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000276:immunology* / Q000821:virology; D051193:Toll-Like Receptors / Q000235:genetics / Q000276:immunology; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000276:immunology; D019562:Viral Load; D014902:West Nile virus / Q000502:physiology*
chemical_list: C485671:BAMBI protein, human; D018925:Chemokines; D008565:Membrane Proteins; D051193:Toll-Like Receptors; D016212:Transforming Growth Factor beta