title: Hepatitis C virus core and NS3 antigens induced conjunctival inflammation via toll-like receptor-mediated signaling.
abstract: OBJECTIVE
  Dry eye condition is an extrahepatic manifestation associated with chronic hepatitis C virus (HCV) infection. Since conjunctival inflammation can contribute to the dry eye condition, in the present study we analyzed the conjunctival inflammatory response to HCV core and NS3 proteins.
  
  
  METHODS
  We used primary human conjunctival fibroblasts for our study. Cytokines were measured with enzyme-linked immunosorbent assay (ELISA). Toll-like receptor (TLR) and cell adhesion molecule gene expression patterns were analyzed with semiquantitative reverse transcription (RT)-PCR. Immunofluorescence staining was performed for the MyD88, nuclear factor-kappa B (NF-kB), and inducible nitric oxide synthase (iNOS) proteins. Nitric oxide (NO) was measured with the Griess assay; terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end labeling (TUNEL) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were performed for apoptosis and cell viability, respectively.
  
  
  RESULTS
  When exposed to the HCV core and NS3 proteins, the conjunctival fibroblasts secreted interleukin-8 (IL-8), IL-6, tumor necrosis factor-alpha (TNF-α), and IL-10 in a dose-dependent manner. Various TLRs were involved in the innate immune response via MyD88 signaling without NF-kB involvement. The gene expression of cell adhesion molecules such as CD44 and ICAM-1 was upregulated, and the cells secreted NO via iNOS. As the sum of these stress responses, the cells underwent apoptosis, which eventually lead to cell death.
  
  
  CONCLUSIONS
  HCV core and NS3 proteins induced conjunctival inflammation that may form the pathogenesis of dry eye condition.
authors.affiliation: L & T Microbiology Research Centre, Vision Research Foundation, Sankara Nethralaya, Chennai, India ; Centre for Nanotechnology and Advanced Biomaterials, SASTRA, Thanjavur, India.
authors.forename: Ayilam Ramachandran
authors.initials: AR
authors.lastname: Rajalakshmy
authors.affiliation: L & T Microbiology Research Centre, Vision Research Foundation, Sankara Nethralaya, Chennai, India.
authors.forename: Jambulingam
authors.initials: J
authors.lastname: Malathi
authors.affiliation: L & T Microbiology Research Centre, Vision Research Foundation, Sankara Nethralaya, Chennai, India.
authors.forename: Hajib Naraharirao
authors.initials: HN
authors.lastname: Madhavan
authors.affiliation: Medical Research Foundation, Sankara Nethralaya, Chennai, India.
authors.forename: Bhaskar
authors.initials: B
authors.lastname: Srinivasan
authors.affiliation: Medical Research Foundation, Sankara Nethralaya, Chennai, India.
authors.forename: Geetha Krishnan
authors.initials: GK
authors.lastname: Iyer
mesh_terms: D003228:Conjunctiva / Q000276:immunology / Q000378:metabolism / Q000473:pathology / Q000821:virology; D016207:Cytokines / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D005347:Fibroblasts / Q000276:immunology / Q000378:metabolism* / Q000473:pathology / Q000821:virology; D005786:Gene Expression Regulation; D016174:Hepacivirus / Q000235:genetics / Q000276:immunology*; D018936:Hepatitis C Antigens / Q000235:genetics / Q000276:immunology*; D054884:Host-Pathogen Interactions; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics / Q000276:immunology; D007249:Inflammation / Q000276:immunology / Q000378:metabolism / Q000473:pathology / Q000821:virology; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics / Q000276:immunology; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000276:immunology; D016328:NF-kappa B / Q000235:genetics / Q000276:immunology; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000276:immunology; D061251:Primary Cell Culture; D015398:Signal Transduction; D051193:Toll-Like Receptors / Q000235:genetics / Q000276:immunology*; D014758:Viral Core Proteins / Q000235:genetics / Q000276:immunology*; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000276:immunology*; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D016207:Cytokines; D018936:Hepatitis C Antigens; D018960:Hyaluronan Receptors; D018799:Intercellular Adhesion Molecule-1; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D051193:Toll-Like Receptors; D014758:Viral Core Proteins; D017361:Viral Nonstructural Proteins; C497483:CD44 protein, human; C507779:MYD88 protein, human; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C496319:NOS2 protein, human