Severe coronavirus disease 19 (COVID-19) is a disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). Patients with COVID-19 are at significantly increased risk of thrombosis, which can be a challenge to manage and is associated with elevated mortality and morbidity. The underlying causes of thrombosis are still largely unknown, although platelet hyperactivity and a procoagulant state are likely to be contributory factors. One of the main mechanisms by which the virus can enter cells and replicate is by binding of the spike protein to the ACE-2 receptor. Although platelets do not express ACE2.
SARS-CoV2 is unique amongst coronaviruses that infect humans in that the envelope spike protein of SARS-CoV2 includes an arginine-glutamate-aspartate (RGD) peptide sequence in its receptor-binding domain (RBD). In platelets, RGD sequences are recognised by the main platelet activation and adhesion integrin – αIIbβ3 – triggering integrin activation, outside-in signalling, and platelet activation. We recently found that purified SARS-CoV2 spike protein and RBD protein can trigger platelet spreading and that this is blocked by incubating the platelets with the clinically used non peptide RGD mimetic αIIbβ3-integrin blocker, tirofiban. This MSc project will extend these observations and investigate the effect of the virus/virus particles/proteins on platelet activation and thrombus formation under flow. We will study direct and indirect effects of virus/viral particles/proteins on platelet activation, the latter including contributions from endothelial and immune cells, as well as plasma from COVID19 patients. Techniques that will include a range of cell biology, biochemical and pharmacological techniques, including cell culture, transfection and protein expression, immunoblotting, phlebotomy, platelet isolation, platelet aggregation, adhesion assays, in vitro thrombosis studies, activation markers and platelet/leukocyte aggregate formation by FACS analysis and confocal microscopy.
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