The Role of Circulating Microvesicles in COVID-19

This is a unique opportunity to join a cutting edge research team investigating novel aspects of immunity in COVID-19 pathogenesis.
The current COVID-19 pandemic to date has resulted in more than 30 million cases and close to a million reported deaths worldwide. It has had a major impact on the way we live our lives and the global economy. The causative virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is capable of human-to-human transmission and infections spread rapidly. The virus not only replicates within the lower respiratory tract but also induces a severe inflammatory response. Death occurs not only because of the viral infection but also because of the exaggerated and aggressive host response resulting in tissue damage and organ failure. During this inflammatory response, high levels of pro-inflammatory cytokines are released from activated immune cells, including neutrophils, monocytes and lymphocytes, in a cascade event known as the cytokine storm. It is thought nearly a third of deaths in patients with COVID-19 are as a direct result of this. Therefore, controlling the excessive inflammation and reducing the activation of cells may be of great benefit to these patients.
Activated cells also release microvesicles (MVs); these are large extracellular vesicles known to contain proteins, mRNA and microRNA that have been shown by us and others to play a role in inflammation. We have recently shown that MVs released from activated neutrophils can be taken up by endothelial cells and enhance inflammation in inflamed vascular beds (Gomez et al, Nature Commun. 2020). Human studies have shown that these MVs are present in the circulation of healthy subjects but are elevated in a number of inflammatory conditions including sepsis, vasculitis and diabetes. However, due to the novel nature of COVID-19, their role in this disease has not been established. We are currently investigating whether hospitalised patients with COVID-19 have altered levels of circulating microvesicles and whether these MVs can alter the function of endothelial cells. This project would complement these studies and investigate the hypothesis that circulating microvesicles interact with immune cells and alter their function in COVID19. You will investigate whether MVs from COVID-19 patients act differently than those from healthy subjects in relation to their ability to induce immune cell activation. You will also investigate whether this is through altered uptake of MVs by these immune cells and/or due to changes in the cargo of MVs from COVID-19 patients.

The research questions that will be addressed by this project are:
• Do circulating MVs from COVID-19 patients alter the activation status of immune cells differently to those from healthy subjects;
• Is this difference dependent on the internalisation of MVs;
• What cargo (protein, RNA) relating to immune cell activation is altered in MVs from COVID-19 patients compared to healthy subjects;
• Does inhibiting the delivery of this cargo prevent immune cell activation.

Key skills that will be developed by you during the project are:
• Primary cell isolation in Category Containment 3 laboratories;
• Quantification and characterisation of MV populations using flow cytometry and nanoparticle tracking analysis;
• Characterisation of immune cell activation status using flow cytometry and ELISA;
• Bioinformatics analysis of microRNA sequencing data.