title: Caspase-3 contributes to ZO-1 and Cl-5 tight-junction disruption in rapid anoxic neurovascular unit damage.
abstract: BACKGROUND
  Tight-junction (TJ) protein degradation is a decisive step in hypoxic blood-brain barrier (BBB) breakdown in stroke. In this study we elucidated the impact of acute cerebral ischemia on TJ protein arrangement and the role of the apoptotic effector protease caspase-3 in this context.
  
  
  RESULTS
  We used an in vitro model of the neurovascular unit and the guinea pig whole brain preparation to analyze with immunohistochemical methods the BBB properties and neurovascular integrity. In both methodological approaches we observed rapid TJ protein disruptions after 30 min of oxygen and glucose deprivation or middle cerebral artery occlusion, which were accompanied by strong caspase-3 activation in brain endothelial cells (BEC). Surprisingly only few DNA-fragmentations were detected with TUNEL stainings in BEC. Z-DEVD-fmk, an irreversible caspase-3 inhibitor, partly blocked TJ disruptions and was protective on trans-endothelial electrical resistance.
  
  
  CONCLUSIONS
  Our data provide evidence that caspase-3 is rapidly activated during acute cerebral ischemia predominantly without triggering DNA-fragmentation in BEC. Further we detected fast TJ protein disruptions which could be partly blocked by caspase-3 inhibition with Z-DEVD-fmk. We suggest that the basis for clinically relevant BBB breakdown in form of TJ disruptions is initiated within minutes during ischemia and that caspase-3 contributes to this process.
authors.affiliation: Institute of Physiology and Pathophysiology, University Medical Center of the Johannes Gutenberg-University of Mainz, Mainz, Germany.
authors.forename: Christoph M
authors.initials: CM
authors.lastname: Zehendner
authors.forename: Laura
authors.initials: L
authors.lastname: Librizzi
authors.forename: Marco
authors.initials: M
authors.lastname: de Curtis
authors.forename: Christoph R W
authors.initials: CR
authors.lastname: Kuhlmann
authors.forename: Heiko J
authors.initials: HJ
authors.lastname: Luhmann
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000378:metabolism / Q000473:pathology*; D002199:Capillary Permeability / Q000502:physiology; D053148:Caspase 3 / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D057167:Claudins / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism / Q000502:physiology; D006168:Guinea Pigs; D002534:Hypoxia, Brain / Q000378:metabolism / Q000473:pathology*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D010750:Phosphoproteins / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D019108:Tight Junctions / Q000378:metabolism* / Q000473:pathology; D013997:Time Factors; D062826:Zonula Occludens-1 Protein
chemical_list: D057167:Claudins; D008565:Membrane Proteins; D010750:Phosphoproteins; C569043:Tjp1 protein, mouse; D062826:Zonula Occludens-1 Protein; D053148:Caspase 3