Masters Thesis

Under Pressure: Role of a Bacterial-like Mechanosensitive Channel in Trypanosoma Cruzi Osmoregulation and Infectivity

Chagas disease is a tropical parasitic disease caused by the protozoan parasite Trypanosoma cruzi (T. cruzi). During its life cycle, T. cruzi faces environmental challenges as it propagates from an insect vector to a mammalian host, for which it has developed robust regulatory responses. However, the sensory machinery utilized by T. cruzi to regulate the responses is unknown. In all cell types, mechanosensation is responsible for detecting changes in pressure, osmosensation and the fluidity of the membrane. It is also associated with quorum sensing and activation of virulence factors. In silico analysis of the T. cruzi genome revealed the presence of a bacterial-like mechanosensitive channel, TcMscS. To investigate the physiological role of TcMscS in T. cruzi, the level of expression was manipulated by CRISPR/Cas9 methods. Immunofluorescence assays showed a differential localization of TcMscS in the main life stages of the parasite, suggesting stage-dependent functions. CRISPR/Cas9 mutant parasites showed significant defects in replication indicating that TcMscS is important for the growth of T. cruzi. Under hyposmotic stress, the ability of the parasite to regulate the cell volume was dependent on TcMscS expression levels. Furthermore, CRISPR/Cas9 mutants have significant defects in metacyclogenesis, as well as, host-cell invasion and intracellular replication. Overall, this study shows that TcMscS is important in T. cruzi physiological processes of osmoregulation and host-cell infectivity.

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