title: Proteomic analysis in pterygium; upregulated protein expression of ALDH3A1, PDIA3, and PRDX2.
abstract: OBJECTIVE
  To identify differentially expressed proteins in the pterygium compared to healthy conjunctiva using a proteomic analysis.
  
  
  METHODS
  Pterygial and healthy conjunctival tissues were obtained from 24 patients undergoing pterygium excision. Total proteins of the pterygia and healthy conjunctiva were analyzed with one-dimensional electrophoresis, and protein bands of interest were excised and subjected to liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-MS/MS) using Thermo's Finnigan ProteomeX workstation LTQ linear ion trap MS/MS. Using bioinformatics, differentially expressed proteins were classified, and three proteins closely involved in the response to oxidative stress were selected for further validation. Differential expression of these proteins was confirmed with western blot and immunohistochemistry.
  
  
  RESULTS
  A web-based gene ontology program, DAVID, was used to classify 230 proteins that were differentially expressed in pterygial tissues. Among these genes, we chose three proteins, aldehyde dehydrogenase, dimeric NADP-preferring (ALDH3A1), protein disulfide-isomerase A3 (PDIA3), and peroxiredoxin-2 (PRDX2), that were significantly upregulated in pterygium and further increased in recurrent pterygium. Immunohistochemistry and western blot analysis confirmed that these three proteins were mainly detected in the basal epithelial layer, and their expression was significantly increased in the pterygium compared to normal conjunctiva.
  
  
  CONCLUSIONS
  This study reported increased expression of ALDH3A1, PDIA3, and PRDX2 in pterygia using a proteomic approach. These proteins are presumed to have a protective role against oxidative stress-induced apoptosis. This result is consistent with the hypothesis that oxidative stress is a significant factor in the pathogenesis of pterygia.
authors.affiliation: Department of Ophthalmology, Hando Hospital, Ansan, Korea.
authors.forename: Sun Woong
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Department of Bioengineering and Institute for Bioengineering and Biopharmaceutical Research, Hanyang University, Seoul, Korea.
authors.forename: Jonghoon
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Bioengineering and Institute for Bioengineering and Biopharmaceutical Research, Hanyang University, Seoul, Korea.
authors.forename: Boram
authors.initials: B
authors.lastname: Lee
authors.affiliation: Department of Bioengineering and Institute for Bioengineering and Biopharmaceutical Research, Hanyang University, Seoul, Korea.
authors.forename: Taiyoun
authors.initials: T
authors.lastname: Rhim
mesh_terms: D000328:Adult; D000444:Aldehyde Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D017209:Apoptosis; D002853:Chromatography, Liquid; D003228:Conjunctiva / Q000166:cytology / Q000378:metabolism; D005260:Female; D063990:Gene Ontology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D054464:Peroxiredoxins / Q000235:genetics / Q000378:metabolism*; D019704:Protein Disulfide-Isomerases / Q000235:genetics / Q000378:metabolism*; D040901:Proteomics; D011625:Pterygium / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D012008:Recurrence; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D015854:Up-Regulation
chemical_list: C086065:PRDX2 protein, human; D054464:Peroxiredoxins; C480021:ALDH3A1 protein, human; D000444:Aldehyde Dehydrogenase; D019704:Protein Disulfide-Isomerases; C085868:PDIA3 protein, human