title: Neutrophil serine proteases exert proteolytic activity on endothelial cells.
abstract: Neutrophil serine proteases (NSPs) are released from activated neutrophils during inflammation. Here we studied the transfer of the three major NSPs, namely proteinase 3, human neutrophil elastase, and cathepsin G, from neutrophils to endothelial cells and used an unbiased approach to identify novel endothelial NSP substrates. Enzymatically active NSPs were released from stimulated neutrophils and internalized by endothelial cells in a dose- and time-dependent manner as shown by immunoblotting, flow cytometry, and the Boc-Ala substrate assay. Using terminal-amine isotopic labeling of substrates in endothelial cells, we identified 121 peptides from 82 different proteins consisting of 36 substrates for proteinase 3, 30 for neutrophil elastase, and 28 for cathepsin G, respectively. We characterized the extended cleavage pattern and provide corresponding IceLogos. Gene ontology analysis showed significant cytoskeletal substrate enrichment and confirmed several cytoskeletal protein substrates by immunoblotting. Finally, ANCA-stimulated neutrophils released all three active NSPs into the supernatant. Supernatants increased endothelial albumin flux and disturbed the endothelial cell cytoskeletal architecture. Serine protease inhibition abrogated this effect. Longer exposure to NSPs reduced endothelial cell viability and increased apoptosis. Thus, we identified novel NSP substrates and suggest NSP inhibition as a therapeutic measure to inhibit neutrophil-mediated inflammatory vascular diseases.
authors.affiliation: Experimental and Clinical Research Center, a joint cooperation between the Charité and the Max-Delbrück Center for Molecular Medicine (MDC), Berlin, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Jerke
authors.affiliation: MDC, Berlin, Germany.
authors.forename: Daniel Perez
authors.initials: DP
authors.lastname: Hernandez
authors.affiliation: MDC, Berlin, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Beaudette
authors.affiliation: INSERM U-1100 Universite Francois Rabelais, Tours, France.
authors.forename: Brice
authors.initials: B
authors.lastname: Korkmaz
authors.affiliation: MDC, Berlin, Germany.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Dittmar
authors.affiliation: Experimental and Clinical Research Center, a joint cooperation between the Charité and the Max-Delbrück Center for Molecular Medicine (MDC), Berlin, Germany.|Nephrology and Intensive Care Medicine, Charité Campus Virchow, Berlin, Germany.
authors.forename: Ralph
authors.initials: R
authors.lastname: Kettritz
mesh_terms: D008841:Actin Cytoskeleton / Q000201:enzymology; D000418:Albumins / Q000378:metabolism; D017209:Apoptosis; D056649:Cathepsin G / Q000378:metabolism; D002460:Cell Line; D002463:Cell Membrane Permeability; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D006801:Humans; D019272:Leukocyte Elastase / Q000378:metabolism; D053146:Myeloblastin / Q000378:metabolism; D018375:Neutrophil Activation; D009504:Neutrophils / Q000201:enzymology*; D019899:Paracrine Communication; D059748:Proteolysis; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D015398:Signal Transduction; D013379:Substrate Specificity; D013997:Time Factors
chemical_list: D000418:Albumins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D019272:Leukocyte Elastase; D053146:Myeloblastin