Characterising the heat shock response in Trypanosoma congolense

Aelmans, Marianne and Urbaniak, Mick (2023) Characterising the heat shock response in Trypanosoma congolense. Masters thesis, Lancaster University.

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Abstract

Trypanosoma congolense causes significant economic burden across Sub-Saharan Africa, as it is the causative agent of Animal African Trypanosomiasis (AAT), a wasting disease affecting cattle which currently has no effective pharmaceutical treatment. T. congolense is a close relative of Trypanosoma brucei, they co-infect the same hosts so have been exposed to similar evolutionary selective pressures, and it is expected they will show similarities in host interactions. While T. brucei is a well-studied model organism, very little experimental work has been performed using T. congolense as tools have only recently been developed for genetic manipulation, but now is the time to use them to investigate the survival and infection mechanisms of the parasite. One of the major symptoms of AAT is a high fever which T. congolense responds to by eliciting the heat shock response, an important virulence factor which allows the parasite to survive in the host. The aim of this project is to characterise the T. congolense heat shock response, as understanding the mechanisms involved could pave the way for discovering novel drug targets in this parasite. It was found that T. congolense displays a very different heat shock response to T. brucei at both 41 °C and 42 °C, with 10% more cell death but less severe lag in growth in the 24 hours after heat shock. DHH1 and ZC3H11, proteins shown to be involved in heat shock, were successfully fluorescently tagged in BSF cells for both species, and a distinct re-localisation of DHH1 into foci can be seen in T. brucei cells upon heat shock but not in T. congolense. Flow cytometry analysis of cells in the period after heat shock revealed that both species arrest in G2/M, 4 hours after heat shock for T. brucei and 6 hours for T. congolense, which may be linked to cell cycle phase differentiation. Overall, T. congolense may have a more different heat shock response that T. brucei than expected. This is some of the first work investigating specific pathways in T. congolense and many techniques were successfully competed for the first time in this laboratory.