title: Neutrophil proteinase 3 acts on protease-activated receptor-2 to enhance vascular endothelial cell barrier function.
abstract: OBJECTIVE
  The principle role of the vascular endothelium is to present a semi-impermeable barrier to soluble factors and circulating cells, while still permitting the passage of leukocytes from the bloodstream into the tissue. The process of diapedesis involves the selective disruption of endothelial cell junctions, which could compromise vascular integrity. It is therefore somewhat surprising that neutrophil transmigration does not significantly impair endothelial barrier function. We examined whether neutrophils might secrete factors that promote vascular integrity during the latter stages of neutrophil transmigration, in particular, the role of neutrophil serine proteinase 3 (PR3).
  
  
  RESULTS
  Endothelial cells were treated with PR3 either in its soluble form or in a complex form with cell surface NB1. We observed that PR3 mediated the enhancement of endothelial cell junctional integrity and that this required its proteolytic activity, as well as endothelial cell expression of the protease-activated receptor-2. Importantly, PR3 suppressed the vascular permeability changes and disruption of junctional proteins induced by the action of protease-activated receptor-1 agonists.
  
  
  CONCLUSIONS
  These findings establish the potential for neutrophil-derived PR3 to play a role in reestablishing vascular integrity after leukocyte transmigration and in protecting endothelial cells from protease-activated receptor-1-induced permeability changes that occur during thrombotic and inflammatory events.
authors.affiliation: Blood Research Institute, BloodCenter of Wisconsin, 8727 Watertown Plank Rd, Milwaukee, WI 53051, USA. christopher.kuckleburg@bcw.edu
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kuckleburg
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Newman
mesh_terms: D020013:Calcium Signaling; D002199:Capillary Permeability; D018920:Coculture Techniques; D058851:GPI-Linked Proteins / Q000378:metabolism; D057809:HEK293 Cells; D061307:Human Umbilical Vein Endothelial Cells / Q000201:enzymology*; D006801:Humans; D007519:Isoantigens / Q000378:metabolism; D053146:Myeloblastin / Q000235:genetics / Q000378:metabolism*; D009504:Neutrophils / Q000201:enzymology*; D034622:RNA Interference; D044463:Receptor, PAR-1 / Q000235:genetics / Q000378:metabolism; D044464:Receptor, PAR-2 / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism; D013997:Time Factors; D057705:Transendothelial and Transepithelial Migration; D014162:Transfection; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
chemical_list: C407242:CD177 protein, human; D058851:GPI-Linked Proteins; D007519:Isoantigens; C107953:RAC1 protein, human; D044463:Receptor, PAR-1; D044464:Receptor, PAR-2; D011956:Receptors, Cell Surface; D053146:Myeloblastin; D020830:rac1 GTP-Binding Protein