TcVps34-Vps15 complex is involve in autophagy and promotes metacyclogenesis in Try- panosoma cruzi

SCHOIJET AC; ALONSO GD; STERNLIEB T

Resistencia, Chaco

Congreso; XXX Reunión Anual de la Sociedad Argentina de Protozoología; 2018

Sociedad Argentina de Protozoología

Autophagy is a widespread process that consists in removing old or damaged organelles and cytosolic components through their degradation into the lysosome. In mammals, two kinases differentially regulate the process of autophagy: mTor and PI3K Vps34. In mammals and yeast, Vps34 forms a major complex withthe Beclin 1 and serine-threonine kinase Vps15 proteins to promote the formation and maturation of the autophagosome. Metacyclogenesis is a process that involves the transformation of non-infective epimastigotes into infective metacyclic trypomastigotes, and is a fundamental step in the life cycle of the protozoanTrypanosoma cruzi, the etiological agent of Chagas disease. This process takes place in the insects rectum due to many factors such as shortage of nutrient produced by the fast replication of epimastigotes, specific components of intestinal wall and lumen of the vector, etc. Several changes occur during metacyclogenesis, including nuclear structure modications, chromatin remodeling and differential protein expression, changes in cell morphology, proliferation and infectivity. In addition, it has recently been reported that autophagy promotes this process.In this work, we demonstrate for the first time that parasites of the Y strain that overexpress TcVps34 or TcVps15 induce both autophagy and metacyclogenesis. Whether after a two-hour nutritional stress in TAU medium (Triatomine Articial Urine) or TAU 3AG for 48 hours (TAU supplemented with proline, aspartate, glutamate and glucose), parasites overexpressing TcVps34 or TcVps15 showed higher levels of monodansycadaverine (MDC) staining, a specic in vivo marker for autophagic vacuoles, in comparison to control parasites. Moreover, parasites overexpressing these proteins showed a more intense labeling with the autophagosome marker Atg8.1 in the intermediate forms of differentiated parasites. Finally, TcVps34 or TcVps15 overexpressing cells were able to differentiate to metacyclic tripomastigotes in a higher proportion than wild-type cells, evidenced by DAPI staining and posterior quantication. Taken together, these data demonstrate the key role of phosphatidylinositol 3-phosphate pathway and autophagy process for T. cruzi differentiation and cycle progression.