CONICET | Buscador de Institutos y Recursos Humanos

An in vitro physiological environment for the study of T. cruzi trypomastigotes migration in 3D cultures.T. cruzi presents a wide genetic diversity that is reflected into the six discrete typing units (DTUs), named TcI to TcVI, in which the different strains are currently classified. However, it is not evident that the biological behavior of the different strains correlates with their DTU. Chagas´ disease presents a chronic outcome and the symptoms appear in a percentage of the infected individuals several years after the initial infection. The clinical manifestations are varied (cardiac, digestive and / or neurological disorders) and depend on a number of -still unknown- factors of the host-parasite interplay, even from the beginning of the infection. The presence of high levels of circulating bloodstream trypomastigotes is the hallmark of the initial acute infection. The trypomastigotes invade nucleated cells, where differentiate to amastigotes that replicate in the cytoplasm and differentiate again to trypomastigotes. Then, the infected cells burst and trypomastigotes are released once again to circulation. During the acute phase this cycle repeats itself actively and the bloodstream trypomastigotes disseminate the infection to several organs and tissues. Therefore, the tissular tropism and the intratissular migration capacity of trypomastigotes, could impact later in the disease development. Three-dimensional (3D) cultures are physiologically relevant because mimic the microarchitecture of tissues and provide an environment similar to the encountered in natural infections, bridging the gap between traditional monolayer cultures (2D) and animal models. In this work, we combined the 3D culture technology with host-pathogen interaction, by studying transmigration of T. cruzi trypomastigotes of two representative strains (CL Brener DTU TcVI; SylvioX10 DTU TcI) into 3D spheroids. Spheroids of HeLa cells expressing Actin-RFP were cultured with CFSE-labelled trypomastigotes and transmigration into spheroids was analyzed at 24 h post infection. Images obtained by 3D-reconstruction from confocal microscopy stacks showed that strains with similar infection profile in standard 2D cultures, presented different infection dynamics in 3D spheroids: i.e despite SylvioX10 and CL Brener strains both yield ~70% of HeLa cells infected in 2D cultures (m.o.i.: 10), both strains showed lower capacity to infect cells grown as 3D spheroids, and also with differences between both strains (SylvioX10