title: A novel family of RGD-containing disintegrins (Tablysin-15) from the salivary gland of the horsefly Tabanus yao targets αIIbβ3 or αVβ3 and inhibits platelet aggregation and angiogenesis.
abstract: A novel family of RGD-containing molecules (Tablysin-15) has been molecularly characterised from the salivary gland of the haematophagous horsefly Tabanus yao. Tablysin-15 does not share primary sequence homology to any disintegrin discovered so far, and displays an RGD motif in the N-terminus of the molecule. It is also distinct from disintegrins from Viperidae since its mature form is not released from a metalloproteinase precursor. Tablysin-15 exhibits high affinity binding for platelet αIIbβ3 and endothelial cell αVβ3 integrins, but not for α5β1 or α2β1. Accordingly, it blocks endothelial cell adhesion to vitronectin (IC50 ~1 nM) and marginally to fibronectin (IC50 ~1 μM), but not to collagen. It also inhibits fibroblast growth factor (FGF)-induced endothelial cell proliferation, and attenuates tube formation in vitro. In platelets, Tablysin-15 inhibits aggregation induced by collagen, ADP and convulxin, and prevents static platelet adhesion to immobilised fibrinogen. In addition, solid-phase assays and flow cytometry demonstrates that αIIbβ3 binds to Tablysin-15. Moreover, immobilised Tablysin-15 supports platelet adhesion by a mechanism which was blocked by anti-integrin αIIbβ3 monoclonal antibody (e.g. abciximab) or by EDTA. Furthermore, Tablysin-15 dose-dependently attenuates thrombus formation to collagen under flow. Consistent with these findings, Tablysin-15 displays antithrombotic properties in vivo suggesting that it is a useful tool to block αIIbβ3, or as a prototype to develop antithrombotics. The RGD motif in the unique sequence of Tablysin-15 represents a novel template for studying the structure-function relationship of the disintegrin family of inhibitors.
authors.affiliation: Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan, China.
authors.forename: D
authors.initials: D
authors.lastname: Ma
authors.forename: X
authors.initials: X
authors.lastname: Xu
authors.forename: S
authors.initials: S
authors.lastname: An
authors.forename: H
authors.initials: H
authors.lastname: Liu
authors.forename: X
authors.initials: X
authors.lastname: Yang
authors.forename: J F
authors.initials: JF
authors.lastname: Andersen
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: F
authors.initials: F
authors.lastname: Tokumasu
authors.forename: J M C
authors.initials: JM
authors.lastname: Ribeiro
authors.forename: I M B
authors.initials: IM
authors.lastname: Francischetti
authors.forename: R
authors.initials: R
authors.lastname: Lai
mesh_terms: D020533:Angiogenesis Inhibitors / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D002448:Cell Adhesion / Q000187:drug effects; D049109:Cell Proliferation; D004175:Diptera; D019483:Disintegrins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D039421:Integrin alpha2 / Q000276:immunology / Q000378:metabolism; D039482:Integrin alpha5 / Q000378:metabolism; D039661:Integrin beta3 / Q000276:immunology / Q000378:metabolism; D009842:Oligopeptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010975:Platelet Aggregation Inhibitors / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D012469:Salivary Glands / Q000378:metabolism; D012471:Salivary Proteins and Peptides / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D017819:Viperidae
chemical_list: D020533:Angiogenesis Inhibitors; D000911:Antibodies, Monoclonal; D019483:Disintegrins; D019476:Insect Proteins; D039421:Integrin alpha2; D039482:Integrin alpha5; D039661:Integrin beta3; D009842:Oligopeptides; D010975:Platelet Aggregation Inhibitors; D012471:Salivary Proteins and Peptides; C561917:tablysin-15, Tabanus yao; C047981:arginyl-glycyl-aspartic acid