Análise de alterações da expressão gênica no Trypanosoma cruzi associadas à infecção em diferentes tipos celulares: papel das proteínas de superfície

Abstract

The surface proteins of Trypanosoma cruzi, especially those encoded by multigene families called Trans-sialidases (TS), MASPs, and Mucins, are essential for the parasite's invasion, adhesion, immune system evasion, and adaptation to the diverse environments that it encounters throughout its life cycle. TS represent the largest multigenic family in the T. cruzi genome with over 1400 gene copies, in which around 16 sequences encode enzymatically active TS (aTS), classified as group I-TS. These molecules are expressed predominantly in the infective trypomastigote form, constitute one of the main mechanisms of host interaction and are central targets for understanding the virulence and tissue tropism of T. cruzi. In this work, two complementary studies were conducted to investigate, using different approaches, the role of these surface proteins in T. cruzi infection and adaptation. The first study was intended to understand the impact of Trans-sialidase gene knockout through comparative transcriptomic analysis between wild-type and TS-knockout CL Brener parasites, aiming to identify changes in gene expression associated with the loss of these proteins. The results revealed that the TS knockout did not cause significant changes in the parasite's metabolism (genes present in the core compartment of the genome), but affected genes in the disruptive compartment, especially the MASP and TS families, suggesting a possible compensatory mechanism. These results highlight T. cruzi's ability to remodel its repertoire of surface molecules in response to various changes in the environment and the parasite's genome. The second study aimed to understand whether a population of Y strain parasites expressing Luciferase and maintained for consecutive passages in the same cell line would have altered its infectivity in other cell types, and if so, what the changes in gene expression would be. To this end, trypomastigote forms derived from a population cultured in MEF (fibroblast) cells were used to infect LLCMK2 (epithelial) and AC16 (cardiomyocyte) cells for fifteen passages. The results indicated greater tropism and invasive efficiency of the Y strain in cardiomyocytes, in addition to a tendency toward progressive adaptation to the cell type in which the parasite was maintained. In in vivo infections, the strain maintained its infective capacity regardless of the cell lineage of origin.Taken together, the results of these studies reinforce the central role of surface proteins in the biology of T. cruzi, not only as structural elements of adhesion or invasion, but also as components whose regulatable expression responds to environmental pressures, actively participating in the mechanisms that ensure the survival, dissemination, and pathogenicity of the parasite in different cellular contexts and hosts.