Análise de proteínas diferencialmente reguladas no proteoma total e modificações pós-traducionais nas formas Amastigotas extracelulares (AE) de duas cepas, com diferentes infectividades, de Trypanosoma cruzi

Abstract

Trypanosoma cruzi (T. cruzi) encompasses various strains of obligatory intracellular eukaryotic parasites, which exhibit diversity in their biological processes, notably in their interaction with mammalian hosts. The study of the parasite has enabled the identification of infective strains that can cause Chagas Disease (CD) in humans, while others are non-infective. These strains show differences in their infectivity profiles, which may be partially related to the expression of specific proteins essential for cellular interaction, facilitating host cell invasion. In this study were analyzed the total proteome and post-translational modifications (PTMs: phosphorylation and N-glycosylation) of extracellular amastigote forms (EAs) of the CL (less infective) and G (more infective) strains. The aim of this work was to identify differentially regulated proteins that could aid in better understanding these differences, noting that the parasite, throughout its life cycle, must adapt to different environmental conditions that alter its proteome in response to various internal and external stimuli. We employed mass spectrometry-based proteomics for such purposes. In total, 8012 proteins were identified in the total proteome, along with 3117 phosphoproteins (phosphoproteome) and 813 glycoproteins (N-glycoproteome). Based on the results and the available literature for EAs, we decided to focus on proteins related to the parasite's outer membrane, aiming to understand the relationship between protein abundance and PTMs and the observed differences in the infectivity profiles of the strains. Among the identified proteins, the trans-sialidase (TS) family was selected for more detailed analysis due to its potential role in virulence, with a higher abundance of group II TS observed for the CL strain. We also characterized a hypothetical sequence as a possible Ssp-4, a protein specific to the amastigote form, and demonstrated the validation of a putative serine/threonine kinase, which showed a higher abundance in the CL strain. Likewise, we highlight the upregulation of a group of oligopeptidase B (OpdB) for the G strain. Although further analyses are necessary, we concluded that the data provide an important tool in studying strain infectivity, potentially contributing to the identification of proteins or signaling pathways essential for the parasite's EAs forms, which could be pharmacological targets or aid in the treatment of CD.