title: Hypoxia induces the expression of membrane-type 1 matrix metalloproteinase in retinal glial cells.
abstract: OBJECTIVE
  Fibrovascular tissue formation in diabetic retinopathy necessitates not only angiogenic activity but also proteolytic activity, which is at least in part attributable to the induction of membrane-type 1 matrix metalloproteinase (MT1-MMP) in retinal glial cells. However, little is known about the triggers for MT1-MMP induction in the diabetic retina. In the present study, the effect of tissue hypoxia on MT1-MMP expression in retinal glial cells was investigated.
  
  
  METHODS
  Retinal glial cells were isolated from the rabbit retina and cultured under either normoxic (20% O(2)) or hypoxic (1% O(2)) conditions in the presence or absence of the inhibitor for vascular endothelial growth factor (VEGF) receptor signal transduction or a neutralizing antibody against VEGF. The expression level of MT1-MMP in retinal glial cells was analyzed by reverse transcription-polymerase chain reaction (RT-PCR), real-time PCR, Western blot analysis and immunocytochemistry. Expression of VEGF and VEGF receptors, VEGFR-1 and VEGFR-2, was also examined by RT-PCR.
  
  
  RESULTS
  RT-PCR and real-time PCR analyses showed a 2.3-fold induction of MT1-MMP expression in retinal glial cells under hypoxic conditions. VEGF, especially its isoform VEGF(165), and VEGFR-2 were also upregulated in retinal glial cells by hypoxia, and hypoxia-induced MT1-MMP expression was inhibited in the presence of the VEGFR-2 inhibitor SU1498 or the anti-VEGF antibody.
  
  
  CONCLUSIONS
  Hypoxia can induce MT1-MMP expression in retinal glial cells, and the hypoxia-induced expression of MT1-MMP is mediated by VEGF in an autocrine fashion.
authors.affiliation: Department of Pathology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Kousuke
authors.initials: K
authors.lastname: Noda
authors.forename: Susumu
authors.initials: S
authors.lastname: Ishida
authors.forename: Hajime
authors.initials: H
authors.lastname: Shinoda
authors.forename: Takashi
authors.initials: T
authors.lastname: Koto
authors.forename: Takanori
authors.initials: T
authors.lastname: Aoki
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tsubota
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Oguchi
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Okada
authors.forename: Eiji
authors.initials: E
authors.lastname: Ikeda
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D002934:Cinnamates / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D019084:Fluorescent Antibody Technique, Indirect; D000860:Hypoxia / Q000378:metabolism*; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D009457:Neuroglia / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D011817:Rabbits; D012160:Retina / Q000166:cytology / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000235:genetics / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: D002934:Cinnamates; D012333:RNA, Messenger; C483044:SU 1498; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases