title: A peptide inhibitor of vascular adhesion protein-1 (VAP-1) blocks leukocyte-endothelium interactions under shear stress.
abstract: Vascular adhesion protein-1 (VAP-1) is an endothelial adhesion molecule mediating leukocyte interactions with blood vessels during leukocyte extravasation. Molecularly VAP-1 is a cell-surface-expressed ecto-enzyme belonging to the group of semicarbazide-sensitive amine oxidases (SSAO; EC 2.4.6.3), which deaminate primary amines. Here we asked whether peptides displaying a suitable free amine group could be a substrate or inhibitor of SSAO and thus regulate VAP-1-mediated leukocyte adhesion. On the basis of a molecular model of VAP-1, we designed synthetic peptides that fit to the substrate channel of VAP-1. One of these lysine-containing peptides effectively inhibits VAP-1-dependent lymphocyte rolling and firm adhesion to primary endothelial cells under physiologically relevant shear conditions. The same peptide inhibits the SSAO activity of endothelial and recombinant VAP-1 in a selective and long-lasting manner. We also show that all enzymatically active VAP-1 is displayed on the cell surface. Our results suggest that, in addition to soluble amines, specific cell-surface-bound molecules containing free NH(2) groups in a suitable position may modulate the enzymatic activity of SSAO. Moreover, the inhibitory peptide diminishes leukocyte interactions with endothelial cells under conditions of shear, and thus it may be useful to treat inflammatory conditions.
authors.affiliation: MediCity Research Laboratory, Tykistökatu 6a, 20520 Turku, Finland.
authors.forename: Gennady G
authors.initials: GG
authors.lastname: Yegutkin
authors.forename: Tiina
authors.initials: T
authors.lastname: Salminen
authors.forename: Kaisa
authors.initials: K
authors.lastname: Koskinen
authors.forename: Christian
authors.initials: C
authors.lastname: Kurtis
authors.forename: Michael J
authors.initials: MJ
authors.lastname: McPherson
authors.forename: Sirpa
authors.initials: S
authors.lastname: Jalkanen
authors.forename: Marko
authors.initials: M
authors.lastname: Salmi
mesh_terms: D006631:Amine Oxidase (Copper-Containing) / Q000037:antagonists & inhibitors* / Q000737:chemistry; D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D015815:Cell Adhesion Molecules / Q000037:antagonists & inhibitors* / Q000737:chemistry; D004727:Endothelium / Q000378:metabolism*; D007962:Leukocytes / Q000378:metabolism*; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry; D008958:Models, Molecular; D010455:Peptides / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011817:Rabbits
chemical_list: D000596:Amino Acids; D015815:Cell Adhesion Molecules; D008565:Membrane Proteins; D010455:Peptides; C076668:AOC3 protein, human; D006631:Amine Oxidase (Copper-Containing)