Platelets are blood cells with numerous crucial pathophysiological roles in hemostasis, cardiovascular thrombotic events and cancer metastasis. Platelet activation requires the engagement of intracellular signalling pathways that involve protein-protein interactions (PPIs). A better understanding of these pathways is therefore crucial for the development of selective anti-platelet drugs. New strategies for studying PPIs in human platelets are required to overcome limitations associated with conventional platelet research methods. For example, small molecule inhibitors can lack selectivity and are often difficult to design and synthesise. Additionally, development of transgenic animal models is costly and time-consuming and conventional recombinant techniques are ineffective due to the lack of a nucleus in platelets. Herein, we describe the generation of a library of novel, functionalised stapled peptides and their first application in the investigation of platelet PPIs. Moreover, the use of platelet-permeable stapled Bim BH3 peptides confirms the part of Bim in phosphatidyl-serine (PS) exposure and reveals a role for the Bim protein in platelet activatory processes. Our work demonstrates that functionalised stapled peptides are a complementary alternative to conventional platelet research methods, and could make a significant contribution to the understanding of platelet signalling pathways and hence to the development of anti-platelet drugs.
This work was funded by a British Heart Foundation project grant to Dr Nicholas Pugh (PG/14/47/30912). The Spring lab acknowledges support from EPSRC, BBSRC, MRC and the Royal Society. J. I. would like to thank Trinity College, University of Cambridge for a Geoffrey Moorhouse Gibson studentship. J. G would like to thank the BBSRC Doctoral Training Programme and AstraZeneca for funding. We would like to thank Dr Marco Di Antonio, Balasubramanian group for helping with CD spectra. We thank A*STAR Singapore for support.