RAB32 AND RAB9 ARE PRESENT IN THE TRYPANOSOMA CRUZI PARASITOPHOROUS VACUOLE AND CONTRIBUTE TO THE INFECTION PROCESS

SALASSA, BETIANA NEBAÍ; CUETO, JUAN AGUSTÍN; VANRELL, MARÍA CRISTINA; ROMANO, PATRICIA SILVIA

Workshop; HOST-PATHOGEN INTERACTION MEETING I; 2021

Introduction: Trypanosoma cruzi, the etiological agent of Chagas disease, is a protozoan parasite which infects both phagocytic and non-phagocytic mammalian cells. At early stages of infection, trypomastigotes localize in a vesicular compartment called the T. cruzi parasitophorous vacuole (TcPV) until the escape to cell cytoplasm to continue their cycle. Rab and SNAREs proteins take part in the molecular machinery of membrane traffic. Rab GTPases have emerged as central regulators of vesicle recognition and transport, whereas SNAREs are mainly involved in the fusion process between membranes. In a previous work, we proposed that the T. cruzi infection process in non-phagocytic cells occurs in two stages, the formation and the maturation of the TcPV. Indeed, we showed that VAMP7 is required for the TcPV development and for the establishment of infection. Objective: The aim of this work was to identify other molecular components of the vesicular transport pathways and their participation in the T. cruzi infection. CHO cells were transfected to overexpress GFP-Rab proteins and infected with trypomastigotes for different times. Materials and methods: cells were fixed and processed to detect intracellular parasites by indirect immunofluorescence. Similar procedures were performed in CHO cells overexpressing GFPvector as control. Results and conclusions: By confocal microscopy, we observed that Rab9 was recruited to the membrane of the TcPV during both stages: formation and maturation of the TcPV. Likewise, we detected that Rab32 was also recruited to TcPV during its maturation, in parallel with VAMP7. Interestingly, the recruitment to TcPV of both, Rab9 and Rab32, were dependent on T. cruzi due to it did not occur on latex beads or when parasite protein synthesis was inhibited. In addition, we found that the overexpression of Rab32 significantly increased T. cruzi infection. We concluded that both Rab9 and Rab32 are important for the intracellular cycle of T. cruzi favoring the formation and /or the maturation of the TcPV that results in an increased infection.