title: Recombinant ADAMTS13 reduces tissue plasminogen activator-induced hemorrhage after stroke in mice.
abstract: OBJECTIVE
  Tissue plasminogen activator (tPA) is approved for treatment of acute ischemic stroke, but it increases the risk of cerebral hemorrhage. Accumulating evidence suggests that von Willebrand factor (VWF) plays a pivotal role in thrombus formation and microcirculatory disturbances after ischemic stroke. By cleaving VWF, ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) protects mice from stroke. Therefore, we hypothesized that recombinant ADAMTS13 (rADAMTS13) could increase the safety of tPA thrombolysis in stroke.
  
  
  METHODS
  We examined blood-brain barrier (BBB) permeability after intraventricular injection of tPA, VWF, and rADAMTS13 in nonischemic mice. We investigated the role of rADAMTS13 on reducing tPA-induced BBB dysfunction and cerebral hemorrhage in a mouse stroke model.
  
  
  RESULTS
  Intraventricular injection of tPA or VWF under nonischemic conditions resulted in a significant increase in BBB permeability. In contrast, rADAMTS13 blocked both tPA- and VWF-induced BBB opening. BBB disruption following stroke was exacerbated by intravenous administration of tPA, but this was attenuated by injection of rADAMTS13. Correspondingly, tPA-associated hemorrhage after stroke was significantly reduced by rADAMTS13. The antihemorrhagic effect of rADAMTS13 was reversed by injection of recombinant VWF. We also showed that rADAMTS13 inhibited tPA-mediated upregulation of vascular endothelial growth factor (VEGF) in vascular endothelium after stroke. The upregulation of VEGF was suppressed by either an Akt inhibitor wortmannin or a Rho kinase inhibitor fasudil. Furthermore, rADAMTS13 downregulated tPA-induced phosphorylation of Akt and activation of RhoA.
  
  
  CONCLUSIONS
  These findings demonstrate that the VWF-cleaving protease rADAMTS13 reduced tPA-induced hemorrhage by regulating BBB integrity, and suggest that this effect may occur through the Akt/RhoA-mediated VEGF pathways.
authors.affiliation: State Key Laboratory of Medical Neurobiology, Shanghai Medical College and Institutes of Brain Science, Fudan University, Shanghai, China.
authors.forename: Lixiang
authors.initials: L
authors.lastname: Wang
authors.forename: Wenying
authors.initials: W
authors.lastname: Fan
authors.forename: Ping
authors.initials: P
authors.lastname: Cai
authors.forename: Mengchen
authors.initials: M
authors.lastname: Fan
authors.forename: Ximin
authors.initials: X
authors.lastname: Zhu
authors.forename: Yiqin
authors.initials: Y
authors.lastname: Dai
authors.forename: Chungang
authors.initials: C
authors.lastname: Sun
authors.forename: Yannan
authors.initials: Y
authors.lastname: Cheng
authors.forename: Ping
authors.initials: P
authors.lastname: Zheng
authors.forename: Bing-Qiao
authors.initials: BQ
authors.lastname: Zhao
mesh_terms: D051722:ADAM Proteins / Q000494:pharmacology*; D000071120:ADAMTS13 Protein; D000818:Animals; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000378:metabolism; D002545:Brain Ischemia / Q000188:drug therapy / Q000378:metabolism; D002543:Cerebral Hemorrhage / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control*; D004195:Disease Models, Animal; D004347:Drug Interactions; D004359:Drug Therapy, Combination / Q000379:methods; D005343:Fibrinolytic Agents / Q000494:pharmacology*; D006801:Humans; D007276:Injections, Intraventricular; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology*; D020521:Stroke / Q000188:drug therapy* / Q000378:metabolism; D010959:Tissue Plasminogen Activator / Q000494:pharmacology*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000378:metabolism; D020742:rhoA GTP-Binding Protein
chemical_list: D005343:Fibrinolytic Agents; D011994:Recombinant Proteins; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; C514862:Akt1 protein, mouse; D051057:Proto-Oncogene Proteins c-akt; D010959:Tissue Plasminogen Activator; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human; C526380:RhoA protein, mouse; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein