Investigating the contribution of attached Leishmania parasite forms in human infections

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Country: UK

Type: Ph.D. Project

Deadline: December 13, 2024

Details: https://www.dimen.org.uk/applications

 

About the Project

Leishmania parasites are responsible for causing a collection of devastating diseases affecting millions of people worldwide. They are spread via infected female sand flies, who feed on blood to produce eggs. Inside the sand fly, Leishmania proliferate and eventually differentiate into one of two forms. The metacyclic form parasites are the motile, infectious cells that invade human macrophages and the second, haptomonad form remains less well characterized. Haptomonad form parasites attach to the sand fly stomodeal valve, maintaining infections after a bloodmeal, and causing damage to the valve, which improves regurgitation during a feed (Yanase et al. 2024, Serafim et al. 2018). Interestingly, recent data shows that haptomonad form cells may also infect macrophages and form a large part of the infectious dose (Catta-Preta et al. 2024). This implicates haptomonad form Leishmania as an important and understudied component of human infections. The cellular signalling involved in commitment to becoming a haptomonad and mechanism of attachment remains elusive. You will uncover how attached Leishmania contribute to infection by addressing the following objectives:

• Determine infectivity of haptomonad form Leishmania 

• Uncover the mechanism by which Leishmania establish an attachment 

• Explore strategies to disrupt disease transmission 

This project will entail a range of cutting-edge technologies in genetic manipulation, protein-protein interactions and cell signalling pathway deconvolution. You will expand a barcoded knockout library for the development and optimization of an attachment assay. Next generation sequencing will produce results for quantitative analysis of barcode representation.  Protein-protein interactions will be explored by expression of Leishmania extracellular domains as biotinylated proteins expressed in HEX cells. These will be clustered around streptavidin to make tetramers to probe for attachment to PSG and sand fly culture lines. Validation and characterization of outputs will involve genetic manipulation, cell staining, flow cytometry and proteomic methods.

Impact and Novelty:

This research will provide an improved understanding of the parasite life cycle, specifically disease transmission. There are no vaccines or drugs which can prevent infection. New transmission blocking strategies depend on a comprehensive knowledge of parasite-insect interaction. The primary supervisor has Leishmania mutants which can be used to produce cell cultures containing an exceptionally high proportion of this life cycle stage which is otherwise rare. These, along with proteomic and transcriptomic datasets generated using them, provide a unique tool. Two novel methods will be used for assessing attachment, a kinome-wide barcoded library (Baker et al. 2021) and a Leishmania cell surface library (Roberts et al. 2024). 

Supervision and support:

The supervisory team combines expert knowledge in molecular parasitology and host-parasite interactions through cellular signalling. The primary supervisor is the recent recipient of a career development award and will provide much of the practical training. During the project you will gain training in a variety of both lab-based skills and computer-based analysis of data. Our laboratories provide a supportive and collaborative environment in which a PhD student can expand their range and learn new techniques.

Supervisor: Nicola Baker

Second supervisor: Prof. Gavin Wright

Benefits of being in the DiMeN DTP:

This project is part of the Discovery Medicine North Doctoral Training Partnership (DiMeN DTP), a diverse community of PhD students across the North of England researching the major health problems facing the world today. Our partner institutions (Universities of Leeds, Liverpool, Newcastle, York and Sheffield) are internationally recognised as centres of research excellence and can offer you access to state-of-the-art facilities to deliver high impact research.

We are very proud of our student-centred ethos and committed to supporting you throughout your PhD. As part of the DTP, we offer bespoke training in key skills sought after in early career researchers, as well as opportunities to broaden your career horizons in a range of non-academic sectors.

Being funded by the MRC means you can access additional funding for research placements, training opportunities or internships in science policy, science communication and beyond.

References:

Yanase, R., Pruzinova, K., Owino, B.O. et al. Discovery of essential kinetoplastid-insect adhesion proteins and their function in Leishmania-sand fly interactions. Nat Commun 15, 6960 (2024). https://doi.org/10.1038/s41467-024-51291-z

Serafim, T.D., Coutinho-Abreu, I.V., Oliveira, F. et al. Sequential blood meals promote Leishmania replication and reverse metacyclogenesis augmenting vector infectivity. Nat Microbiol 3, 548–555 (2018). https://doi.org/10.1038/s41564-018-0125-7

Carolina Catta-Preta, Kashinath Ghosh, David Sacks et al. Single-cell atlas of Leishmania major development in the sandfly vector reveals the heterogeneity of transmitted parasites and their role in infection, 18 March 2024, PREPRINT (Version 1) available at Research Square. https://doi.org/10.21203/rs.3.rs-4022188/v1

Baker, N., Catta-Preta, C.M.C., Neish, R. et al. Systematic functional analysis of Leishmania protein kinases identifies regulators of differentiation or survival. Nat Commun 12, 1244 (2021). https://doi.org/10.1038/s41467-021-21360-8

Roberts AJ, Ong HB, Clare S, Brandt C, Harcourt K, Takele Y, Ghosh P, Toepp A, Waugh M, Matano D, Färnert A, Adams E, Moreno J, Mbuchi M, Petersen C, Mondal D, Kropf P, Wright GJ. A panel of recombinant Leishmania donovani cell surface and secreted proteins identifies LdBPK_323600.1 as a serological marker of symptomatic infection. mBio 15:e00859-24 (2024). https://doi.org/10.1128/mbio.00859-24

Funding Notes

Studentships are fully funded by the Medical Research Council (MRC) for 4yrs. Funding will cover tuition fees, stipend (£19,237 for 2024/25) and project costs. We also aim to support the most outstanding applicants from outside the UK and are able to offer a limited number of full studentships to international applicants.

Studentships commence: 15 Sep 2025

Good luck!