title: Microarray and protein analysis of human pterygium.
abstract: OBJECTIVE
  Pterygium is a sunlight-related, ocular-surface lesion that can obscure vision. In order to identify specific genes that may play a role in pterygium pathogenesis, we analyzed the global gene expression profile of pterygium in relation to autologous conjunctiva.
  
  
  METHODS
  Oligonucleotide microarray hybridization was used to compare the gene expression profile between human whole pterygium and autologous conjunctiva. Selected genes were further characterized by RT-PCR, western blot, and immunohistochemistry, and comparisons were made with limbal and corneal tissues.
  
  
  RESULTS
  Thirty-four genes exhibited a 2 fold or greater difference in expression between human whole pterygium and autologous conjunctiva. Twenty-nine transcripts were increased and five transcripts were decreased in pterygium. Fibronectin, macrophage-inflammatory protein-4 (MIP-4), and lipocalin 2 (oncogene 24p3; NGAL) were increased 9, 5, and 2.4 fold, respectively, while Per1 and Ephrin-A1 were decreased 2 fold in pterygium. Western blots showed that fibronectin and MIP-4 were increased in pterygium compared to limbus, cornea, and conjunctiva. Immunohistochemical analysis showed fibronectin in the stroma; lipocalin 2 in the basal epithelial cells, basement membrane, and extracellular stroma; and MIP-4 in all areas of the pterygium.
  
  
  CONCLUSIONS
  These data show both novel and previously identified extracellular-matrix-related, proinflammatory, angiogenic, fibrogenic, and oncogenic genes expressed in human pterygium. Comparisons of selected genes with limbal and corneal tissues gave results similar to comparisons between pterygium and normal conjunctiva. The increased expression of lipocalin 2, which activates matrix metalloproteinases (MMP), is consistent with our previous findings that MMP-9 and other MMPs are highly expressed in pterygium basal epithelium.
authors.affiliation: National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA. aryankalayilm@mail.nih.gov
authors.forename: Molykutty
authors.initials: M
authors.lastname: John-Aryankalayil
authors.forename: Nicholas
authors.initials: N
authors.lastname: Dushku
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Jaworski
authors.forename: Constance A
authors.initials: CA
authors.lastname: Cox
authors.forename: Gregory
authors.initials: G
authors.lastname: Schultz
authors.forename: Janine A
authors.initials: JA
authors.lastname: Smith
authors.forename: Keri E
authors.initials: KE
authors.lastname: Ramsey
authors.forename: Dietrich A
authors.initials: DA
authors.lastname: Stephan
authors.forename: Kenn A
authors.initials: KA
authors.lastname: Freedman
authors.forename: Ted W
authors.initials: TW
authors.lastname: Reid
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Carper
mesh_terms: D000209:Acute-Phase Proteins / Q000378:metabolism; D015153:Blotting, Western; D000075906:Chemokine CCL26; D019742:Chemokines, CC / Q000378:metabolism; D003228:Conjunctiva / Q000378:metabolism; D005136:Eye Proteins / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D000071068:Lipocalin-2; D054834:Lipocalins; D020411:Oligonucleotide Array Sequence Analysis; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D011625:Pterygium / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000209:Acute-Phase Proteins; C111792:CCL18 protein, human; C120429:CCL26 protein, human; D000075906:Chemokine CCL26; D019742:Chemokines, CC; D005136:Eye Proteins; D005353:Fibronectins; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins