title: Lipopolysaccharide regulation of toll-like receptor-4 and matrix metalloprotease-9 in human primary corneal fibroblasts.
abstract: OBJECTIVE
  Toll-like receptor 4 (TLR4) is a key component of the innate immune response related to microbial keratitis (MK). Pathways and downstream effectors relating to TLR signaling remain unknown in human bacterial MK. To this effect, by activating the TLR4 signaling cascade with lipopolysaccharide (LPS), the authors investigated whether TLR4, matrix metalloproteases (MMP)-2, MMP-9, and cytokine expression in diseased human primary corneal fibroblasts (CFs) were altered.
  
  
  METHODS
  Human primary CFs from patients with severe corneal ulceration were cultured in conjunction with healthy control CFs and treated with LPS derived from Pseudomonas aeruginosa.
  
  
  RESULTS
  TLR4, MMP-2, and MMP-9 were constitutively expressed in both ulcerated and control CFs. Diseased CFs showed greater responsiveness to LPS stimulation. TLR4 and MMP-9 expression was dose-dependently increased by LPS. MMP-2 expression was not affected by LPS. Analysis on cytokine expression revealed that IL-2, IL-8, IL-10, IL-12p70, GM-CSF, IFNγ, and TNFα expression increased after LPS treatment but only in diseased cells.
  
  
  CONCLUSIONS
  TLR4 activation with LPS increases TLR4, MMP-9, and cytokine expression in CFs cultured from patients with microbial keratitis. Overexpression of these products may provide a local mechanism to eradicate bacterial infection but may also aid corneal ulceration and perforation.
authors.affiliation: Division of Infection, Inflammation and Immunity, Faculty of Medicine, University of Southampton, Southampton, United Kingdom.
authors.forename: Yuk
authors.initials: Y
authors.lastname: Wong
authors.forename: Claire
authors.initials: C
authors.lastname: Sethu
authors.forename: Fethi
authors.initials: F
authors.lastname: Louafi
authors.forename: Parwez
authors.initials: P
authors.lastname: Hossain
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015153:Blotting, Western; D002478:Cells, Cultured; D003315:Cornea / Q000187:drug effects* / Q000378:metabolism; D003320:Corneal Ulcer / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D008875:Middle Aged; D011550:Pseudomonas aeruginosa; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9