Thiol isomerases as novel antithrombotic targets
An exciting recent discovery in the thrombosis field is that thiol isomerases form a new clotting pathway. Thiol isomerases are a group of enzymes that regulate the function of blood cell receptors and clotting proteins by reacting with their disulphide bonds. We have identified a thiol isomerase, named ERp5, which is released into the circulation from activated platelets and promotes clot formation in vivo.
In this project we will dissect the role of ERp5 in platelet function and clot formation by using mice with genetic deletion of ERp5 in their platelets. We will investigate how this thiol isomerase regulates the interaction of platelets with clotting proteins (fibrinogen, von Willebrand factor) and vascular cells (endothelial cells and neutrophils). We will explore the potential of ERp5 inhibitors to prevent thrombus formation and become candidate antithrombotic drugs.
Redox biomarkers in thrombotic disease
The redox balance (balance of reduction and oxidation reactions in our blood) is essential for a healthy circulation. Redox imbalance causes alterations of protein function contributing to the development of thrombosis. The Haematology Group is focused on redox modification of disulphide bonds in two proteins critical for thrombus formation: the platelet receptor integrin a2bb3 and the plasma protein von Willebrand factor. We have found that reduced forms of a2bb3 and vWF have decreased thrombotic activity and may therefore protect from thrombotic disease, such as venous clots.
We have developed assays which measure the redox balance in blood including tests which measure the disulphide reducing activity of plasma and the production of reactive oxygen species by platelets. We will study the redox modifications of platelet a2bb3 and plasma vWF which occur in patients at high risk for thrombosis to identify those most likely to benefit from drugs which restore the normal redox balance.
Developing biochips for the evaluation of haemostasis and thrombosis
Many patients with bleeding and clotting disorders go undetected by routine laboratory tests in part because the available assays do not reflect the conditions in the circulation. The Haematology Group uses biochips in a microfluidic system that allows blood to flow through passages under controlled conditions. The passages are designed to mimic blood vessels and include features, eg, stenosis, that simulate the circulation in stenosed vessels. The flow of blood through these biochips generates thrombi that can be visualised by real-time microscopy and quantified.
This project will study blood cell adhesion and thrombus formation in microfluidic devices to assess for persisting thrombotic tendency in patients with a history of venous clots, who have completed treatment. Samples from patients with bleeding disorders, on treatment, will be assessed for haemostatic potential. Blood cells and proteins which participate in clot formation will be measured in the microfluidics system including platelets, fibrin, neutrophil extracellular traps and von Willebrand factor.