TcVps34-Vps15 complex coordinates the crosstalk between autophagy and metacyclogenesis in Trypanosoma cruzi

SCHOIJET, A.C.; ALONSO GD; STERNLIEB T

Mar del Plata

Congreso; ANNUAL MEETING OF BIOSCIENCE SOCIETIES 2019, XXXI Annual Meeting of Sociedad Argentina de Protozoología (SAP); 2019

Autophagy is a conserved process along evolution and is essential for the maintenance of cellular homeostasis. However, trypanosomatids seem to possess a less complex route, or different proteins not yet identified. This process can be up-regulated during stress, starvation, or infection. In mammals, two kinases differentially regulate the process of autophagy: mTor and a phosphatidylinositol 3-kinase, Vps34, which interact with a regulatory subunit, Vps15. Metacyclogenesis is a fundamental process in the life cycle of the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease. This process involves the transformation of non-infective epimastigotes into infective metacyclic trypomastigotes. Several changes occur during metacyclogenesis, and autophagy was found to be strongly upregulated during this process. In this work, we demonstrate that parasites overexpressing TcVps34 or TcVps15 proteins enhance both, autophagy and metacyclogenesis. TcVps34 or TcVps15 overexpressing epimastigotes were able to differentiate to metacyclic forms in a higher proportion than wild-type cells. Parasites overexpressing these proteins showed a more intense labeling with the autophagosome marker Atg8.1 and higher levels of monodansycadaverine (MDC) staining, a specific in vivo marker for autophagic vacuoles, in the intermediate forms of differentiated parasites, in comparison to control parasites. To extend this study we are also performing assays with DQ-BSA, to evaluate degradative compartments, since the induction of autophagy is characterized by an increase in the number of lysosomes/autolysosomes required for the lysis of trapped components. In addition, we will study the effect of autophagy regulatory drugs such as rapamycin and wortmanin in transgenic parasites during metacyclogenesis. Taken together, these data demonstrate the key role of phosphatidylinositol 3-phostate pathway in autophagy, T. cruzi differentiation and cell cycle progression.