Systematic identification of key components of the interferon response against human cytomegalovirus

Supervisors: Finn Grey, Sam Wilson

Project description:

Disease outcome from virus infection depends on complex host pathogen interactions. Rational design of therapies, vaccines and disease control depends on understanding these interactions at the molecular level. In the Grey lab we use cutting edge systems biology approaches to identify and characterise host genes involved in virus infections.

The long-term goal of this project is to identify and characterize key components of the interferon (IFN) response to human cytomegalovirus (HCMV). IFNs are a crucial first line of defence against viral infection. They also shape the adaptive immune response by triggering release of cytokines and chemokines. Developing a better understanding of the interferon response and how viruses counteract its effects has important implications for how we treat viral infections and the development of vaccines.

HCMV is a highly prevalent herpesvirus, infecting between 30% and 100% of the population, depending on socio-economic status. HCMV infection is a significant cause of morbidity and mortality in immunocompromised individuals, those with heart disease and recipients of solid organ and bone marrow transplants. HCMV is also the leading cause of infectious congenital birth defects resulting from spread of the virus to neonates. There is no vaccine against HCMV and side effects and viral resistance diminish the effectiveness of current antiviral therapies.

While HCMV can cause problems in certain populations, infection is normally asymptomatic due to effective control of virus replication by various arms of the immune system. Although HCMV has evolved multiple mechanisms to subvert and inhibit antiviral effects of IFNs, evidence would suggest they still play a vital role in controlling replication and pathogenesis. Individuals with mutations in key IFN signalling genes are lethally susceptible to HCMV infections and recombinant IFN has been successfully used in treating congenital HCMV and HCMV infection in AIDS patients. Furthermore, murine CMV is more lethal in IFN knockout mice.

Interferon stimulates the expression of hundreds of cellular genes. Which of these genes re important in limiting virus replication is poorly understood. Recently, arrayed expression libraries have been constructed containing over 400 interferon-stimulated genes (ISGs), allowing systematic screening of their effects on virus replication

1-3. We have combined this technology with CRISPR/Cas9 knockout cells containing deletions in key components of the IFN signalling pathway, allowing precise characterization of the effects of individual ISGs on HCMV replication through loss of function assays.

Building on the current exciting preliminary data the project will involve identify and characterizing the key components of the interferon response to HCMV using arrayed ISG expression screens in CRISPR/Cas9 KO cells. This is an ideal project for an enthusiastic student. The project is based on exciting preliminary data, provides ample opportunity to gain experience in cutting edge techniques in a vibrant research environment with the support of two supervisors with a track record in high impact publications.

References:

1          Dittmann, M. et al. A serpin shapes the extracellular environment to prevent influenza A virus maturation. Cell 160, 631-643, doi:10.1016/j.cell.2015.01.040 (2015).

2          Kane, M. et al. Identification of Interferon-Stimulated Genes with Antiretroviral Activity. Cell host & microbe 20, 392-405, doi:10.1016/j.chom.2016.08.005 (2016).

3          Schoggins, J. W. et al. A diverse range of gene products are effectors of the type I interferon antiviral response. Nature 472, 481-485, doi:10.1038/nature09907 (2011).

 

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