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Lee WH, Schaffner-Reckinger E, Tsoukatos DC, Aylward K, Moussis V, Tsikaris V, Trypou P, Egot M, Baruch D, Kieffer N, Bachelot-Loza C. Inhibition of αIIbβ3 Ligand Binding by an αIIb Peptide that Clasps the Hybrid Domain to the βI Domain of β3. PLoS One 2015; 10:e0134952. [PMID: 26332040 PMCID: PMC4557944 DOI: 10.1371/journal.pone.0134952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 07/15/2015] [Indexed: 11/22/2022] Open
Abstract
Agonist-stimulated platelet activation triggers conformational changes of integrin αIIbβ3, allowing fibrinogen binding and platelet aggregation. We have previously shown that an octapeptide, p1YMESRADR8, corresponding to amino acids 313–320 of the β-ribbon extending from the β-propeller domain of αIIb, acts as a potent inhibitor of platelet aggregation. Here we have performed in silico modelling analysis of the interaction of this peptide with αIIbβ3 in its bent and closed (not swing-out) conformation and show that the peptide is able to act as a substitute for the β-ribbon by forming a clasp restraining the β3 hybrid and βI domains in a closed conformation. The involvement of species-specific residues of the β3 hybrid domain (E356 and K384) and the β1 domain (E297) as well as an intrapeptide bond (pE315-pR317) were confirmed as important for this interaction by mutagenesis studies of αIIbβ3 expressed in CHO cells and native or substituted peptide inhibitory studies on platelet functions. Furthermore, NMR data corroborate the above results. Our findings provide insight into the important functional role of the αIIb β-ribbon in preventing integrin αIIbβ3 head piece opening, and highlight a potential new therapeutic approach to prevent integrin ligand binding.
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Affiliation(s)
- Wen Hwa Lee
- SGC, University of Oxford, Oxford, United Kingdom
| | - Elisabeth Schaffner-Reckinger
- Laboratoire de Biologie et Physiologie Intégrée, (CNRS/GDRE-ITI), University of Luxembourg, Luxembourg City, Luxembourg
| | | | - Kelly Aylward
- Inserm UMR_S 1140, Faculté de pharmacie, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Vassilios Moussis
- Department of Chemistry, Section of Organic Chemistry and Biochemistry, Ioannina, Greece
| | - Vassilios Tsikaris
- Department of Chemistry, Section of Organic Chemistry and Biochemistry, Ioannina, Greece
| | - Paraskevi Trypou
- Department of Chemistry, Section of Organic Chemistry and Biochemistry, Ioannina, Greece
| | - Marion Egot
- Inserm UMR_S 1140, Faculté de pharmacie, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Dominique Baruch
- Inserm UMR_S 1140, Faculté de pharmacie, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Nelly Kieffer
- Laboratoire de Biologie et Physiologie Intégrée, (CNRS/GDRE-ITI), University of Luxembourg, Luxembourg City, Luxembourg
- CNRS-LIA124, Sino-French Research Center for Life Sciences and Genomics, Rui Jin Hospital, Jiao Tong University School of Medicine, Shanghai, China
| | - Christilla Bachelot-Loza
- Inserm UMR_S 1140, Faculté de pharmacie, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- * E-mail:
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Dimitriou AA, Stathopoulos P, Mitsios JV, Sakarellos-Daitsiotis M, Goudevenos J, Tsikaris V, Tselepis AD. Inhibition of platelet activation by peptide analogs of the beta(3)-intracellular domain of platelet integrin alpha(IIb)beta(3) conjugated to the cell-penetrating peptide Tat(48-60). Platelets 2010; 20:539-47. [PMID: 19863457 DOI: 10.3109/09537100903324219] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Activation of the platelet integrin-receptor alpha(IIb)beta(3) is the final pathway of platelet aggregation, regardless of the initiating stimulus. Many studies suggest that there are several cytoplasmic proteins such as talin and beta(3)-endonexin that bind to N(744)PLY(747) and N(756)ITY(759) motif of the beta(3) cytoplasmic tail and play the major role in the receptor activation. In this study, we investigated the role of the membrane distal region of human beta(3) cytoplasmic tail and specifically the N(743)NPLYKEA(750) and T(755)NITYRGT(762) sequence that contains an NXXY motif, in platelet aggregation, secretion, alpha(IIb)beta(3) activation (PAC-1 binding) and fibrinogen binding. We synthesized two peptides corresponding to the above sequences as well as their conjugates with the Tat(48-60) cell-penetrating peptide. The capability of conjugates to penetrate the platelet membrane was investigated with confocal laser scanning microscopy using carboxyfluorescein (CF)-labeled peptides. Our results showed that the conjugated with the Tat(48-60) sequence peptides penetrate the platelet membrane and inhibit platelet aggregation in both PRP and washed platelets in a dose-dependent manner. The Tat-beta(3)743-750 conjugate exhibited similar inhibitory activity in PRP and in washed platelets whereas the Tat-beta(3)755-762 conjugate was more potent inhibitor of aggregation in washed platelets than in PRP. Both conjugated peptides were also able to inhibit P-selectin membrane expression as well as PAC-1 and fibrinogen binding to the platelets, the Tat-beta(3)755-762 conjugate being more potent than Tat-beta(3)743-750. The Tat(48-60) peptide and the peptides beta(3)743-750 and beta(3)755-762, which were not conjugated to the Tat(48-60) sequence, did not exhibit any inhibitory effect on the above parameters. In conclusion, the present study shows for the first time that the peptide analogs of the intracellular domain of the beta(3) subunit beta(3)743-750 and beta(3)755-762 conjugated to the cell-penetrating peptide Tat(48-60) are capable of penetrating the platelet membrane and expressing biological activity by inhibiting the activation of alpha(IIb)beta(3), the fibrinogen binding to the activated receptor as well as platelet aggregation. Further studies are necessary to support whether such conjugated peptides may be useful tools for the development of potent antiplatelet agents acting intracellularly through the platelet integrin alpha(IIb)beta(3).
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Affiliation(s)
- Andromaxi A Dimitriou
- Laboratory of Biochemistry, Medical School, University of Ioannina, 45110 Ioannina, Greece
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Conformational Studies of the 313-320 and 313-332 Peptide Fragments Derived from the αIIb Subunit of Integrin Receptor with Molecular Dynamics Simulations. Int J Pept Res Ther 2009. [DOI: 10.1007/s10989-009-9187-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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