title: Effect of cyclical mechanical stretch and exogenous transforming growth factor-beta1 on matrix metalloproteinase-2 activity in lamina cribrosa cells from the human optic nerve head.
abstract: OBJECTIVE
  Extensive remodeling of the lamina cribrosa extracellular matrix occurs in primary open angle glaucoma. The transforming growth factor-beta (TGF-beta) and matrix metalloproteinase (MMP) protein families are implicated in this process. The authors investigated (a). the effect of cyclical mechanical stretch on TGF-beta1 mRNA synthesis, TGF-beta1 protein secretion, MMP-2 protein activity and (b). the effect of exogenous TGF-beta1 on MMP-2 protein activity in human lamina cribrosa cells in vitro.
  
  
  METHODS
  Primary human lamina cribrosa cells grown on flexible and rigid plates were exposed to cyclical stretch (1Hz, 15%) or static conditions for 12 and 24 hours. Cells grown on 100-mm plates were exposed to human TGF-beta1 (10 ng/ml) or vehicle (4 mM HCl/1% BSA) for 24 hours. TGF-beta1 mRNA synthesis in stretched and static cells was measured using real-time polymerase chain reaction. TGF-beta1 protein secretion in stretched and static cell media was measured using enzyme linked immunosorbent assay. Gelatin zymography measured MMP-2 activity in stretched, static, TGF-beta1- treated and vehicle-treated cell media.
  
  
  RESULTS
  Cyclical stretch induced significant increases in TGF-beta1 mRNA synthesis after 12 hours (**P < 0.01) and TGF-beta1 protein secretion after 24 hours (*P < 0.05). Cyclical stretch significantly (*P < 0.05) increased MMP-2 activity in cell media after 24 hours. Exogenous TGF-beta 1 induced a significant (**P < 0.01) increase in cell media MMP-2 activity after 24 hours.
  
  
  CONCLUSIONS
  These results suggest that cyclical stretch and TGF-beta1 modulate MMP-2 activity in human lamina cribrosa cells. TGF-beta 1 and MMP-2 release from lamina cribrosa cells may facilitate matrix remodeling of the optic nerve head in primary open angle glaucoma.
authors.affiliation: Institute of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland. ruaidhri.kirwan@ucd.ie
authors.forename: Ruaidhrí P
authors.initials: RP
authors.lastname: Kirwan
authors.forename: John K
authors.initials: JK
authors.lastname: Crean
authors.forename: Cecilia H
authors.initials: CH
authors.lastname: Fenerty
authors.forename: Abbot F
authors.initials: AF
authors.lastname: Clark
authors.forename: Colm J
authors.initials: CJ
authors.lastname: O'Brien
mesh_terms: D018929:Cell Culture Techniques; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D009898:Optic Disk / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D012333:RNA, Messenger / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013314:Stress, Mechanical; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1
chemical_list: D012333:RNA, Messenger; C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D020778:Matrix Metalloproteinase 2