LM14 defined medium enables continuous growth of Trypanosoma cruzi

Small molecule mediators of host-T. cruzi-environment interactions in Chagas disease

Small molecules (less than 1,500 Da) include major biological signals that mediate host-pathogen-microbiome communication. They also include key intermediates of metabolism and critical cellular building blocks. Pathogens present with unique nutritional needs that restrict pathogen colonization or promote tissue damage. In parallel, parts of host metabolism are responsive to immune signaling and regulated by immune cascades. These interactions can trigger both adaptive and maladaptive metabolic changes in the host, with microbiome-derived signals also contributing to disease progression. In turn, targeting pathogen metabolic needs or maladaptive host metabolic changes is an important strategy to develop new treatments for infectious diseases. Trypanosoma cruzi is a single-celled eukaryotic pathogen and the causative agent of Chagas disease, a neglected tropical disease associated with cardiac and intestinal dysfunction. Here, we discuss the role of small molecules during T. cruzi infection in its vector and in the mammalian host. We integrate these findings to build a theoretical interpretation of how maladaptive metabolic changes drive Chagas disease and extrapolate on how these findings can guide drug development.

Physiological, proteomic, and metabolomic analysis provide insights into Bacillus sp.-mediated salt tolerance in wheat

Herein, the inoculation with strain wp-6 promoted the growth of wheat seedlings by improving the energy production and conversion of wheat seedlings and alleviating salt stress. Soil salinization decreases crop productivity due to high toxicity of sodium ions to plants. Plant growth-promoting rhizobacteria (PGPR) have been demonstrated to alleviate salinity stress. However, the mechanism of PGPR in improving plant salt tolerance remains unclear. In this study, physiological analysis, proteomics, and metabolomics were applied to investigate the changes in wheat seedlings under salt stress (150 mM NaCl), both with and without plant root inoculation with wp-6 (Bacillus sp.). Under salt stress, root inoculation with strain wp-6 increased plant biomass (57%) and root length (25%). The Na⁺ content was reduced, while the K⁺ content and K⁺/Na⁺ ratio were increased. The content of malondialdehyde was decreased by 31.94% after inoculation of wp-6 under salt stress, while the content of proline, soluble sugar, and soluble protein were increased by 7.48%, 12.34%, and 4.12%, respectively. The peroxidase, catalase, and superoxide dismutase activities were increased after inoculation of wp-6 under salt stress. Galactose metabolism, phenylalanine metabolism, caffeine metabolism, ubiquinone and other terpenoid-quinone biosynthesis, and glutathione metabolism might play an important role in promoting the growth of salt-stressed wheat seedlings after the inoculation with wp-6. Interaction analysis of differentially expressed proteins and metabolites found that energy production and transformation-related proteins and six metabolites (D-arginine, palmitoleic acid, chlorophyllide b, rutin, pheophorbide a, and vanillylamine) were mainly involved in the growth of wheat seedlings after the inoculation with wp-6 under salt stress. Furthermore, correlation analysis found that inoculation with wp-6 promotes the growth of salt-stressed wheat seedlings mainly through regulating amino acid metabolism and porphyrin and chlorophyll metabolism. This study provides an eco-friendly method to increase agricultural productivity and paves a way to sustainable agriculture.

Genome-Wide Proteomics and Phosphoproteomics Analysis of Trypanosoma cruzi During Differentiation

Trypanosoma cruzi is a pathogenic protozoan that still has an impact on public health, despite the decrease in the number of infection cases along the years. T. cruzi possesses an heteroxenic life cycle in which it differentiates in at least four forms. Among the differentiation processes, metacyclogenesis has been exploited in different views by researchers. An intriguing question that rises is how metacyclogenesis is triggered and controlled by cell signaling and which are the differentially expressed proteins and posttranslational modifications involved in this process. An important cell signaling pathway is the protein phosphorylation, and it is reinforced in T. cruzi in which the gene expression control occurs almost exclusively posttranscriptionally. Additionally, the number of protein kinases in T. cruzi is relatively high compared to other organisms. A way to approach these questions is evaluating the cells through phosphoproteomics and proteomics. In this chapter, we will describe the steps from the cell protein extraction, digestion and fractionation, phosphopeptide enrichment, to LC-MS/MS analysis as well as a brief overview on peptide identification. In addition, a published method for in vitro metacyclogenesis will be detailed.

Quantitative phosphoproteome and proteome analyses emphasize the influence of phosphorylation events during the nutritional stress of Trypanosoma cruzi: the initial moments of in vitro metacyclogenesis

Phosphorylation is an important event in cell signaling that is modulated by kinases and phosphatases. In Trypanosoma cruzi, the etiological agent of Chagas disease, approximately 2% of the protein-coding genes encode for protein kinases. This parasite has a heteroxenic life cycle with four different development stages. In the midgut of invertebrate vector, epimastigotes differentiate into metacyclic trypomastigotes in a process known as metacyclogenesis. This process can be reproduced in vitro by submitting parasites to nutritional stress (NS). Aiming to contribute to the elucidation of mechanisms that trigger metacyclogenesis, we applied super-SILAC (super-stable isotope labeling by amino acids in cell culture) and LC-MS/MS to analyze different points during NS. This analysis resulted in the identification of 4205 protein groups and 3643 phosphopeptides with the location of 4846 phosphorylation sites. Several phosphosites were considered modulated along NS and are present in proteins associated with various functions, such as fatty acid synthesis and the regulation of protein expression, reinforcing the importance of phosphorylation and signaling events to the parasite. These modulated sites may be triggers of metacyclogenesis.

Development of a motion-based cell-counting system for Trypanosoma parasite using a pattern recognition approach

Automated cell counters that utilize still images of sample cells are widely used. However, they are not well suited to counting slender, aggregate-prone microorganisms such as Trypanosoma cruzi. Here, we developed a motion-based cell-counting system, using an image-recognition method based on a cubic higher-order local auto-correlation feature. The software successfully estimated the cell density of dispersed, aggregated, as well as fluorescent parasites by motion pattern recognition. Loss of parasites activeness due to drug treatment could also be detected as a reduction in apparent cell count, which potentially increases the sensitivity of drug screening assays. Moreover, the motion-based approach enabled estimation of the number of parasites in a co-culture with host mammalian cells, by disregarding the presence of the host cells as a static background.

Quantitative proteome and phosphoproteome analyses highlight the adherent population during Trypanosoma cruzi metacyclogenesis

Trypanosoma cruzi metacyclogenesis is a natural process that occurs inside the triatomine vector and corresponds to the differentiation of non-infective epimastigotes into infective metacyclic trypomastigotes. The biochemical alterations necessary for the differentiation process have been widely studied with a focus on adhesion and nutritional stress. Here, using a mass spectrometry approach, a large-scale phospho(proteome) study was performed with the aim of understanding the metacyclogenesis processes in a quantitative manner. The results indicate that major modulations in the phospho(proteome) occur under nutritional stress and after 12 and 24 h of adhesion. Significant changes involve key cellular processes, such as translation, oxidative stress, and the metabolism of macromolecules, including proteins, lipids, and carbohydrates. Analysis of the signalling triggered by kinases and phosphatases from 7,336 identified phosphorylation sites demonstrates that 260 of these sites are modulated throughout the differentiation process, and some of these modulated proteins have previously been identified as drug targets in trypanosomiasis treatment. To the best of our knowledge, this study provides the first quantitative results highlighting the modulation of phosphorylation sites during metacyclogenesis and the greater coverage of the proteome to the parasite during this process. The data are available via ProteomeXchange with identifier number PXD006171.