A high throughput model of Cryptococcus Infection and Cell Biology In Vivo for identifying host and pathogen disease determinants and new therapeutics

Lead Research Organisation: University of Sheffield
Department Name: Infection Immunity & Cardiovasc Disease

Abstract

I am interested in how our immune system is and is not able to remove micro-organisms that can cause disease. An example of where the immune system is not able to work properly is when a person is infected with HIV (the virus that causes AIDS). Other examples include cancer, during and after organ transplantation and during treatment for rheumatoid arthritis. When the immune system is not working properly we may become ill with a micro-organism that normally would not cause a significant problem. One such micro-organism is the fungus Cryptococcus.
Infections with Cryptococcus are very unusual in those with a normal immune system but in individuals with, for example, severe HIV infection, Cryptococcus is much more common and very serious. The AIDS epidemic has resulted in a large group of people who are susceptible to Cryptococcus and it has been estimated that there are as many as 1 million cases and 600, 000 deaths due to Cryptococcus each year. Fungi that cause disease in humans are uncommon and those that cause serious disease are very rare. Fungi that cause serious disease in humans are difficult to treat because the drugs we have are often quite harmful to us as well.
As well as the Cryptococcus that causes serious disease in those with immune systems that are not working, there is a second type that has been found to cause disease in people who have apparently normal immune systems. This second type is mainly found around the equator but there have been increasing numbers outside this area.
My research is trying to understand these different areas of why Cryptococcus causes disease so that we can find better treatments. The questions I am asking in my research are: What happens to the immune system that means we are seriously infected with Cryptococcus? What makes infection with some types of Cryptococcus more severe (virulent)? Are there any new drugs that we can use to improve the way we treat Cryptococcus?
I will explore these questions using a model of Cryptococcus infection I have developed in the zebrafish. The zebrafish has a similar immune system to our own and I can observe the immune cells of living animals and see what happens during the infection. I am also going to use this model to test possible new drugs. My hope is that through this research we will have a greater understanding of how and why Cryptococcus causes disease and that this will lead to new treatments.

Technical Summary

Cryptococcus is a fatal fungal pathogens of humans causing death through meningitis. As a major pathogen of the immunocompromised, especially AIDS patients Cryptococcus causes an estimated six hundred thousand deaths per year. By evading or manipulating phagocytes, particularly macrophages, Cryptococcus is able to cross the immune barriers that normally prevent fatal disseminated disease. Current studies focus on in vitro analysis in isolated cells, such as macrophages or in vivo studies in rodent hosts. However, such approaches are unable to capture the complex cellular events that define how this fatal disease progresses or is stopped. Therefore I have developed a new integrated model of cryptococcosis in zebrafish to simultaneously study host and pathogen factors that determine disease progression and outcome in vivo. The objectives of this model are to identify the underlying causes of cryptococcosis, molecular targets for therapeutic intervention and new therapeutics through my chemical screen. Phase 1a) I will produce quantitative data on disease progression including spatial and temporal growth kinetics. b) I will analyse the innate response to Cryptococcus infection through both imaging of macrophages and neutrophils and measuring expression and activity of molecular markers of innate immunity c) I will study the cell biology of the Cryptococcus:phagocyte interaction in vivo, including the function of the vomocytosis of Cryptococcus from macrophages. Phase 2. I will identify genetic basis of pathogen virulence by examining 4 different groups (directed mutants, 2 hyper-virulent outbreaks and clinical isolates from HIV patients) in my model. Phase 3. I will determine host immune requirements by a) depleting neutrophils and macrophages b) and inhibiting effectors of the innate immune system through knock-down and mutagenesis. Phase 4. I will perform an automated chemical screen to identify new drugs for the reduction of Cryptococcus burden during infection.

Planned Impact

Clinical - 1. Cryptococcosis clinical management (5-20 years). My research will either directly identify new therapeutics or generate new understanding of etiology that leads to development of new therapeutics or stimulates clinical studies and trials that will result in improvement in patient outcomes. 2. Clinician research aims (1-5 years). Communication and discussion of my research will influence the research direction of clinician scientists.
NC3Rs - 1. Refinement and reduction in my adult zebrafish use (2-5 years in the first instance). 2. New virulence model of cryptococcosis (2-10 years) I will actively pursue the adoption of my zebrafish embryo model, where relevant, in replacing rodent use with Cryptococcus community. 3. Wider adoption of zebrafish for infection and immunity research (5-10 years). My fellowship will help expand the profile of the zebrafish as versatile model for infection and immunity.
Economy - 1. Chemical screen (5-20 years) My chemical screen has the potential to generate new drugs treatment of cryptococcosis and new reagents for the research community. 2. Zebrafish transgenics (3-10 years) these may have applications in future drug discovery and as reporter lines. 3. Maintaining excellence in medical research (5-20 years). 4. Providing skilled individuals for the UK work force (5-20 years)
Public engagement and outreach - 1. Infection page on CDBG 'fish for science' website (1-10years) 2. Primary school activities (1-5 years) key stage 2 activities based around measuring and microorganisms 3. A-level talks (1-5 years) Supplement to teaching on immunity looking at host pathogen interactions.
Training and career development - 1. Research group career development (1-5 years) ensuring the career development of those in my research group at all levels. 2. Applied microscopy course (1-10 years) training users of the light microscopy facility understanding and problem solving in light microscopy experiments

Publications

10 25 50
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Ballou ER (2017) The cause and effect of Cryptococcus interactions with the host. in Current opinion in microbiology

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Buckley CM (2016) WASH drives early recycling from macropinosomes and phagosomes to maintain surface phagocytic receptors. in Proceedings of the National Academy of Sciences of the United States of America

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Evans RJ (2020) PPAR-gamma Fun(gi) With Prostaglandin. in Nuclear receptor signaling

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Evans RJ (2017) Using Flow Cytometry to Analyze Cryptococcus Infection of Macrophages. in Methods in molecular biology (Clifton, N.J.)

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Farrer RA (2016) Microevolutionary traits and comparative population genomics of the emerging pathogenic fungus Cryptococcus gattii. in Philosophical transactions of the Royal Society of London. Series B, Biological sciences

 
Title Host pathogen interactions 
Description A sculpture visualising host pathogen interactions and the different microscopy approaches that we use to study them 
Type Of Art Artwork 
Year Produced 2015 
Impact The artwork formed part of a community engagement exercise between art and science 
URL http://www.igniteimaginations.org.uk/
 
Description EPSRC pump priming grant
Amount £24,000 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 03/2016 
End 05/2016
 
Description Krebs Institute Fellowship
Amount £25,000 (GBP)
Organisation University of Sheffield 
Sector Academic/University
Country United Kingdom
Start 11/2012 
End 07/2017
 
Description Medical Research Foundation Equipment grant
Amount £125,580 (GBP)
Funding ID C0494 
Organisation Medical Research Council (MRC) 
Department Medical Research Foundation
Sector Charity/Non Profit
Country United Kingdom
Start 02/2014 
End 10/2014
 
Description Wellcome Trust Strategic Award in Medical Mycology and Fungal Immunology PhD studentship
Amount £108,471 (GBP)
Funding ID 097377/Z/11/Z 
Organisation Wellcome Trust 
Department Wellcome Trust Strategic Award
Sector Charity/Non Profit
Country United Kingdom
Start 09/2014 
End 09/2017
 
Title High content imaging of infection and immunity in zebrafish 
Description We developed and published a high content imaging model data set for cryptococcosis 
Type Of Material Database/Collection of data 
Provided To Others? No  
Impact The ability to follow all macrophage and pathogen cells throughout a vertebrate non-invasively. 
 
Description Cd4 positive monocytic cells in zebrafish 
Organisation University of Manchester
Department Photon Science Institute
Country United Kingdom 
Sector Academic/University 
PI Contribution We generated a new transgenic zebrafish line (fms:GFP) that could be combine with a Cd4 line of our collaborator to label monocytic Cd4 cells in zebrafish for the first time.
Collaborator Contribution Our collaborators provided the Cd4:mCherry zebrafish transgenic.
Impact Research paper (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5073357/)
Start Year 2014
 
Description Development of an in vivo model for the study of the blood brain barrier and choroid plexus. 
Organisation VU University Medical Center
Department Immunology (VUMC-I)
Country Netherlands 
Sector Hospitals 
PI Contribution We conceived, planned and characterized a transgenic zebrafish model of the blood brain barrier and choroid plexus.
Collaborator Contribution Our partner generated the transgenic zebrafish model and performed additional characterization.
Impact Generation of Tg(Claudin5:GFP)VUM1 transgenic zebrafish. Research publication: http://bio.biologists.org/content/7/2/bio030494
Start Year 2014
 
Description KrebFest 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact A science festival celebrating the life and work of Sir Hans Krebs at the University of Sheffield. This included four newly commissioned science/art collaborative works, science discovery events attended by more than 2000 people, schools visits and projects to seven secondary schools.
Year(s) Of Engagement Activity 2015
URL http://krebsfest.group.shef.ac.uk/
 
Description Microscopic Army public engagment 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Presented the use of non-mammalian model organisms for the study of the immune system as part of the Life Festival at the University of Sheffield. The event took place at the Moor markets in Sheffield City Centre.
Year(s) Of Engagement Activity 2016
URL http://microarmy.weebly.com/
 
Description Radio interview related to publication 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Radio interview on the BBC World Service to discuss publication on resistance of birds to fungal infection.
Year(s) Of Engagement Activity 2016
 
Description Radio interview related to publication 2 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Media (as a channel to the public)
Results and Impact Radio interview on the BBC Radio5live to discuss publication on resistance of birds to fungal infection.
Year(s) Of Engagement Activity 2016
 
Description Radio interview related to publication 3 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Media (as a channel to the public)
Results and Impact Radio interview on the BBC Radio Scotland to discuss publication on resistance of birds to fungal infection.
Year(s) Of Engagement Activity 2016
 
Description School Visit (Stannington) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach Local
Primary Audience Schools
Results and Impact More than 200 pupils aged from 7-11 attended on a talk on what a scientist is, with demonstrations, and the role of accidental discovery. There was an extensive question and answer session afterwards.

Future visits and plans for these visits (workshops, further talks) discussed.
Year(s) Of Engagement Activity 2013