Trypanosoma cruzi produces outward mechanical deformations on the host cell plasma membrane before its interaction with lysosomes

ROMANO PATRICIA SILVIA; CUETO JUAN AGUSTIN

Congreso; XXXII Reunión de la Sociedad Argentina de Protozoología; 2020

SAP

Trypanosoma cruzi trypomastigote is highly motile due to its vigorous flagellum. The trypomastigote motility has a major role in the invasion of the host cell. As the parasite actively enters the cell, the vacuole that transiently harbors it, called parasitophorous vacuole (PV), is taking form. This plasma membrane-derived vacuole gradually acquires lysosomal markers as LAMP1 and VAMP7. Particularly interesting is the fact that the flagellar motility persists for a few minutes after the invasion. This explains why, once inside the cell, internalized trypomastigote often causes a marked deformation of the plasma membrane called protrusion. In this work, we aim to characterize this phenomenon. To achieve this, we transfected HeLa cells with a fluorescent plasma membrane marker (PM-GFP) and then infected for different time periods. By mean of fluorescence confocal microscopy, we find that the occurrence of protruding parasites reaches a peak (22,2 %) at 15 minutes post-infection and then decay abruptly during the first hour. In order to study a possible link between protrusions and PV interaction with lysosomes, we co-transfected cells with PM-GFP y LAMP1-RFP plasmids. After increasing periods of infection, the percentage of protruding parasites decreased, whereas LAMP1 enrichment at the PV?s membrane increased, suggesting a process in which lysosomes inhibit the intracellular trypomatigotes motility. Electron microscopy showed that protruding parasites are enveloped by two layers of membrane, one from the vacuole and a second from the evaginated plasma membrane. We can conclude that the protrusions occur mainly during the first 15 minutes post-infection and the subsequent interaction with lysosomes would inhibit this phenomenon. Our results open a new perspective on the biology of Trypanosoma cruzi-host cell interaction based on a biomechanical point of view.