title: Synergistic effect of peptide inhibitors derived from the extracellular and intracellular domain of αIIbsubunit of integrin αIIbβ3on platelet activation and aggregation.
abstract: αIIbβ3, the major platelet integrin, plays a central role in hemostasis and thrombosis. Upon platelet activation, conformation of αIIbβ3changes and allows fibrinogen binding and, subsequently, platelet aggregation. It was previously shown that a lipid-modified platelet permeable peptide, which corresponds to the intracellular acidic membrane distal sequence1000LEEDDEEGE1008of αIIb(pal-K-LEEDDEEGE or pal-K-1000-1008), inhibits thrombin-induced human platelet aggregation, by inhibiting talin association with the integrin. YMESRADR, a peptide corresponding to the extracellular sequence 313-320 of αIIb, is also a potent platelet aggregation inhibitor by mimicking the effect of a clasp between the head domains of αIIband β3. The aim of the present study was to investigate the synergistic effect of the intra- and extracellular- peptide inhibitors on platelet aggregation, as well as on the phosphorylation of two signaling proteins, focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK). Platelet preincubation with Pal-K-LEEDDEGE followed by YMESRADR showed a synergistic inhibitory activity on platelet aggregation. Platelet incubation with threshold inhibitory concentrations of both peptides provoked almost the total inhibition of aggregation, PAC-1 binding, and fibrinogen binding, but not P-selectin exposure on activated platelets' surface. Like RGDS peptide, this mixture inhibits FAK phosphorylation whose phosphorylation is well known to be consecutive to the aggregation (postoccupancy events). However, in contrast to RGDS peptide that enhances ERK phosphorylation and activation, the mixture of threshold inhibitory concentrations of Pal-K-LEEDDEEGE and YMESRADR inhibits ERK phosphorylation. We suggest that the use of the intracellular in combination with the extracellular peptide inhibitor, acting with a non-RGD-like mechanism, may provide an alternative way to antagonize integrin αIIbβ3activation.
authors.affiliation: a Department of Chemistry, Sector of Organic Chemistry and Biochemistry , University of Ioannina , Ioannina , Greece.
authors.forename: Alexia V
authors.initials: AV
authors.lastname: Gkourogianni
authors.affiliation: a Department of Chemistry, Sector of Organic Chemistry and Biochemistry , University of Ioannina , Ioannina , Greece.
authors.forename: Klytaimnistra
authors.initials: K
authors.lastname: Kiouptsi
authors.affiliation: a Department of Chemistry, Sector of Organic Chemistry and Biochemistry , University of Ioannina , Ioannina , Greece.
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Koloka
authors.affiliation: a Department of Chemistry, Sector of Organic Chemistry and Biochemistry , University of Ioannina , Ioannina , Greece.
authors.forename: Vassilios
authors.initials: V
authors.lastname: Moussis
authors.affiliation: a Department of Chemistry, Sector of Organic Chemistry and Biochemistry , University of Ioannina , Ioannina , Greece.
authors.forename: Vassilios
authors.initials: V
authors.lastname: Tsikaris
authors.affiliation: b INSERM UMR S1140 , Faculté de Pharmacie , Paris , France.|c Université Paris Descartes , Sorbonne Paris Cité , Paris , France.
authors.forename: Christilla
authors.initials: C
authors.lastname: Bachelot-Loza
authors.affiliation: a Department of Chemistry, Sector of Organic Chemistry and Biochemistry , University of Ioannina , Ioannina , Greece.
authors.forename: Demokritos C
authors.initials: DC
authors.lastname: Tsoukatos
mesh_terms: D000595:Amino Acid Sequence; D001792:Blood Platelets / Q000187:drug effects* / Q000502:physiology*; D004357:Drug Synergism; D054641:Dual Specificity Phosphatase 2 / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005434:Flow Cytometry; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D006801:Humans; D019007:P-Selectin / Q000378:metabolism; D010455:Peptides / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D015539:Platelet Activation / Q000187:drug effects*; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000737:chemistry*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs
chemical_list: D019007:P-Selectin; D010455:Peptides; D010975:Platelet Aggregation Inhibitors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D051416:Focal Adhesion Protein-Tyrosine Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D054641:Dual Specificity Phosphatase 2
keywords: Integrin αIIbβ3; peptide inhibitors; platelet activation; platelet aggregation; αIIb subunit