title: Integrin cleavage facilitates cell surface-associated proteolysis required for vascular smooth muscle cell invasion.
abstract: Vascular smooth muscle cell (VSMC) invasion is a key element in atherogenesis and restenosis, requiring integrins for adhesion/de-adhesion as well as matrix metalloproteinases (MMPs) for focalized proteolysis. Among the MMP family, pro-MMP-2 is unique in its activation, depending on the formation of a multiprotein complex with MT1-MMP/TIMP-2 at the cell surface, in which integrin alphavbeta3 participates. Integrin alphav and MT1-MMP are synthesized from precursors via furin-dependent cleavage of their pro-peptide. Furin is the prototypical proprotein convertase highly expressed in VSMCs and human atherosclerotic lesions. Its precise role in the tight network involving MMPs/integrins and their coordination and cooperation required for VSMC invasion is unknown. We demonstrate that furin-inhibition with decanoyl-RVKR-chloromethylketone inhibits VSMC invasion in a comparable degree to MMP inhibitors, which reduce the MT1-MMP-MMP-2 proteolytic cascade. Furin-inhibition did not prevent MT1-MMP/MMP-2 maturation. In contrast, it strongly reduced pro-alphav cleavage, but did not lessen its cell membrane expression. However, inhibition of pro-alphav processing via furin-inhibition strongly reduced pro-MMP-2 binding to the cell surface, thereby lessening its full maturation and diminishing the cell surface in situ proteolysis required for invasion. Thus, our data demonstrate a novel mechanism of furin-dependent alphav cleavage that enhances pro-MMP-2 binding and activation at the cell membrane in cooperation with MT1-MMP in primary VSMCs. Processing of alphav by furin contributes to the recruitment of enzymatic energy to the cell surface, thereby providing focalized proteolysis associated with VSMC invasion.
authors.affiliation: Department of Medicine/Cardiology, Deutsches Herzzentrum Berlin, Augustenburger Platz 1, Berlin, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Kappert
authors.forename: Heike
authors.initials: H
authors.lastname: Meyborg
authors.forename: Bernadette
authors.initials: B
authors.lastname: Baumann
authors.forename: Vesna
authors.initials: V
authors.lastname: Furundzija
authors.forename: Jan
authors.initials: J
authors.lastname: Kaufmann
authors.forename: Kristof
authors.initials: K
authors.lastname: Graf
authors.forename: Dietger
authors.initials: D
authors.lastname: Stibenz
authors.forename: Eckart
authors.initials: E
authors.lastname: Fleck
authors.forename: Philipp
authors.initials: P
authors.lastname: Stawowy
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects; D003094:Collagen / Q000378:metabolism; D024042:Collagen Type I / Q000378:metabolism; D003208:Concanavalin A / Q000494:pharmacology; D004338:Drug Combinations; D004792:Enzyme Precursors / Q000378:metabolism; D005434:Flow Cytometry; D045683:Furin / Q000378:metabolism; D005780:Gelatin / Q000378:metabolism; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D007797:Laminin / Q000378:metabolism; D053511:Matrix Metalloproteinase 14 / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D032389:Myocytes, Smooth Muscle / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D011509:Proteoglycans / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D024042:Collagen Type I; D004338:Drug Combinations; D004792:Enzyme Precursors; D016023:Integrins; D007797:Laminin; D011509:Proteoglycans; D003208:Concanavalin A; C059485:matrigel; D005780:Gelatin; D003094:Collagen; D045683:Furin; D053511:Matrix Metalloproteinase 14