title: A novel anti-platelet peptide (Z4A5) potential for glycoprotein IIb/IIIa inhibits platelet aggregation.
abstract: BACKGROUND
  Z4A5 is a novel peptide that inhibits platelet aggregation and formation of platelet thrombi, but the mechanism of its anti-platelet effects remains unknown. This study explores the anti-platelet effect and mechanism of Z4A5.
  
  
  METHODS
  We investigated the anti-platelet activity of Z4A5 on platelet aggregation induced by adenosine diphosphate (ADP), arachidonic acid (AA) and thrombin (TH) in human platelet-rich plasma (PRP). Fibrinogen and PAC-1 binding to glycoproteinIIb/IIIa (GPIIb/IIIa) were measured by flow cytometry. In addition, we investigated the integrin specificity of Z4A5 in attachment and detachment assays using human umbilical vein endothelial cells (HUVEC) and assessed the relative cell number using the MTT assay.
  
  
  RESULTS
  In vitro, Z4A5 inhibited ADP-, AA- and TH-induced human platelet aggregation with IC(50) values of 0.46 ± 0.05 μM (n = 10), 0.23 ± 0.0 5 μM (n = 10) and 0.21 ± 0.02 μM (n = 10), respectively. Z4A5 inhibited fibrinogen, and PAC-1 bound to platelet GPIIb/IIIa with IC(50) values of 0.48 ± 0.07 μM (n = 8) and 0.63 ± 0.12 μM (n = 6), respectively. Z4A5 failed to inhibit α(V)β(3) integrin-mediated HUVEC attachment to vitronectin and did not cause any significant detachment of HUVEC monolayer when compared with the controls.
  
  
  CONCLUSIONS
  Z4A5 is a potential anti-platelet drug that inhibits fibrinogen binding to GPIIb/IIIa, but does not affect the structurally similar integrin α(V)β(3).
authors.affiliation: School of Medicine, Xi'an Jiaotong University, Xi'an Shaanxi, China.
authors.forename: Ying-Xue
authors.initials: YX
authors.lastname: Li
authors.forename: Qiang
authors.initials: Q
authors.lastname: Sun
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Shu-Ting
authors.initials: ST
authors.lastname: Ren
authors.forename: Yi-Ran
authors.initials: YR
authors.lastname: Liao
authors.forename: Ya
authors.initials: Y
authors.lastname: Wang
authors.forename: Xin-Liang
authors.initials: XL
authors.lastname: Shen
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
mesh_terms: D001792:Blood Platelets / Q000187:drug effects*; D002460:Cell Line; D005343:Fibrinolytic Agents / Q000494:pharmacology*; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects; D006801:Humans; D009842:Oligopeptides / Q000494:pharmacology*; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000494:pharmacology
chemical_list: D005343:Fibrinolytic Agents; D009842:Oligopeptides; D010975:Platelet Aggregation Inhibitors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex