title: Caspase-3 activation triggers extracellular cathepsin L release and endorepellin proteolysis.
abstract: Proteolysis of extracellular matrix components and the production of cryptic bioactive factors play key roles in vascular remodeling. We showed previously that extracellular matrix proteolysis is triggered by the apoptosis of endothelial cells (EC), resulting in the release of an anti-apoptotic C-terminal fragment of endorepellin (LG3). Here, we characterize the endorepellin-cleaving proteases released by apoptotic EC using a multifaceted proteomics strategy. Cathepsin L (CathL), a cysteine protease known to be associated with cardiovascular disease progression in animal models and humans, was isolated from medium conditioned by apoptotic EC. CathL cleaved recombinant endorepellin in vitro, leading to LG3 release. Inhibition of CathL activity in EC exposed to pro-apoptotic stimuli prevented LG3 release without modulating the development of apoptosis in EC. Inhibition of caspase-3 activation in EC with the biochemical inhibitor DEVD-fluoromethyl ketone or small interfering RNAs concomitantly prevented CathL release by EC, LG3 production, and the development of paracrine anti-apoptotic activity. These data demonstrate that caspase-3 activation is a novel pathway of importance for triggering extracellular CathL release and the cleavage of extracellular matrix components.
authors.affiliation: Research Centre, Centre Hospitalier Universitaireé de Montréal and Montreal Cancer Institute Université de Montréal, Montreal, Quebec H2L 4M1, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Cailhier
authors.forename: Isabelle
authors.initials: I
authors.lastname: Sirois
authors.forename: Patrick
authors.initials: P
authors.lastname: Laplante
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Lepage
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Raymond
authors.forename: Nathalie
authors.initials: N
authors.lastname: Brassard
authors.forename: Alexandre
authors.initials: A
authors.lastname: Prat
authors.forename: Renato V
authors.initials: RV
authors.lastname: Iozzo
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Pshezhetsky
authors.forename: Marie-Josée
authors.initials: MJ
authors.lastname: Hébert
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002318:Cardiovascular Diseases / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism*; D056668:Cathepsin L; D002403:Cathepsins / Q000378:metabolism*; D002460:Cell Line; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism*; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism*; D006801:Humans; D019899:Paracrine Communication / Q000502:physiology; D010446:Peptide Fragments / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D034741:RNA, Small Interfering
chemical_list: D019812:Heparan Sulfate Proteoglycans; D010446:Peptide Fragments; D010455:Peptides; D034741:RNA, Small Interfering; C071927:perlecan; D002403:Cathepsins; C505407:CASP3 protein, human; D053148:Caspase 3; D003546:Cysteine Endopeptidases; C534281:CTSL protein, human; D056668:Cathepsin L