Unraveling the role of TcVps34-Vps15 complex as a modulator of autophagy and metacyclogenesis in Trypanosoma cruzi

ALEJANDRA C. SCHOIJET; TAMARA STERNLIEB; GUILLERMO D. ALONSO

Modalidad Virtual

Congreso; Molecular Parasitology Meeting XXXI; 2020

Chagas disease affects millions of Latin America individuals; however, due to the immigration of infected people, this illness has emerged in nonendemic countries. Chemotherapy is based on two nitrocompounds, benznidazole and nifurtimox, that show limited effectiveness in chronic phase, culminating in severe collateral effects. Thus, effective therapy against the chronic form of Chagas disease has yet to be discovered and developed. Autophagy is a conserved process along evolution and is essential for the maintenance of cellular homeostasis. The nutritional stress caused by the lack of nutrients is one of the main stimuli that trigger this process. Interestingly, the autophagic molecular machinery is partially present in trypanosomatids, and many components of the yeastand mammalian pathway are lacking in protozoa or have not yet been identified. In mammals, two kinases differentially regulate the process of autophagy: mTor and a phosphatidylinositol 3-kinase, Vps34, which interact with a regulatory subunit, Vps15. It is worth to remark that autophagy was associated with a process called metacyclogenesis, which is essential for the success of Trypanosoma cruzi life cycle. This process involves the transformation of non-infectiveepimastigotes into infective metacyclic trypomastigotes. 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 also perform 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 this sense, we demonstrate that overexpressing epimastigotes subjected to differentiation shown a significant increase in the number of lysosomes. Taken together, these data demonstrate the key role of phosphatidylinositol 3-phostate pathway in autophagy, T. cruzi differentiation and cell cycle progression.