title: Thymosin beta-4 upregulates anti-oxidative enzymes and protects human cornea epithelial cells against oxidative damage.
abstract: BACKGROUND
  The ability to scavenge reactive oxygen species (ROS) is crucial for cornea epithelial cells to resist oxidative damage. The authors previously demonstrated that exogenous thymosin beta-4 (T beta(4)) was able to protect human cornea epithelial (HCE-T) cells against H(2)O(2)-induced oxidative damage, and its cellular internalisation was essential. The aim of this study is to further elucidate its protective mechanism.
  
  
  METHODS
  HCE-T cells with or without T beta(4) pretreatment were exposed to H(2)O(2), and the differences in caspase activity, intracellular ROS levels, cell viability, and the expression of anti-oxidative enzymes, were measured and compared.
  
  
  RESULTS
  Besides reducing caspase-9 activation and intracellular ROS levels induced by H(2)O(2), treatment of T beta(4) could also increase cell viability and stimulate the expression of manganese superoxide dismutase (SOD) and copper/zinc SOD. Moreover, both transcription and translation levels of catalase were also upregulated by T beta(4) in the presence of exogenous H(2)O(2). Furthermore, it was demonstrated that the addition of catalase inhibitor abrogated the protective effect of T beta(4) against H(2)O(2)-induced oxidative damage.
  
  
  CONCLUSIONS
  To the best of the authors' knowledge, this is the first report to show that T beta(4 )was capable of upregulating anti-oxidative enzymes in human corneal epithelial cells, and these findings further support its role in cornea protection.
authors.affiliation: Institute of Biopharmaceutical Science, National Yang-Ming University, 155 Sec 2, Li-Nong Street, Taipei 11221, Taiwan.
authors.forename: J H-C
authors.initials: JH
authors.lastname: Ho
authors.forename: K-C
authors.initials: KC
authors.lastname: Tseng
authors.forename: W-H
authors.initials: WH
authors.lastname: Ma
authors.forename: K-H
authors.initials: KH
authors.lastname: Chen
authors.forename: O K-S
authors.initials: OK
authors.lastname: Lee
authors.forename: Y
authors.initials: Y
authors.lastname: Su
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects; D002374:Catalase / Q000037:antagonists & inhibitors; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019573:Epithelium, Corneal / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D011994:Recombinant Proteins / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013947:Thymosin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects*; D000099201:Thymosin beta(4)
chemical_list: D000975:Antioxidants; D002374:Catalase; D004791:Enzyme Inhibitors; D006861:Hydrogen Peroxide; D011994:Recombinant Proteins; D013947:Thymosin; D000099201:Thymosin beta(4)