Impairment in natural killer cells editing of immature dendritic cells by infection with a virulent Trypanosoma cruzi population

In silico toxicologic profile and in vivo trypanocidal activity of estafietin, a sesquiterpene lactone isolated from Stevia alpina Griseb

Chagas disease is an infection caused by the protozoan Trypanosoma cruzi, affecting 6-8 million people worldwide. Only two drugs are available for its treatment, having a limited efficacy and adverse side-effects. Estafietin is a sesquiterpene lactone isolated from Stevia alpina with in vitro activity against T. cruzi and low cytotoxicity against mammalian cells. The aim of this work was to predict the toxicologic profile of estafietin by in silico methods and assess its in vivo activity on a murine model of Chagas disease. Estafietin showed low toxicity according to pkCSM web tool and passed the PAINS filter from PAINS-remover web server. The treatment of infected mice with 1 mg/Kg/day of estafietin for five consecutive days administrated by intraperitoneal route significatively decreased parasitemia levels and reduced inflammatory infiltrates and myocyte damage on muscle tissue. These results suggest that estafietin had effect both on acute and chronic stages of the infection.

Role of myeloid-derived suppressor cells during Trypanosoma cruzi infection

Chagas disease (CD), caused by the protozoan parasite Trypanosoma cruzi, is the third largest parasitic disease burden globally. Currently, more than 6 million people are infected, mainly in Latin America, but international migration has turned CD into an emerging health problem in many nonendemic countries. Despite intense research, a vaccine is still not available. A complex parasite life cycle, together with numerous immune system manipulation strategies, may account for the lack of a prophylactic or therapeutic vaccine. There is substantial experimental evidence supporting that T. cruzi acute infection generates a strong immunosuppression state that involves numerous immune populations with regulatory/suppressive capacity. Myeloid-derived suppressor cells (MDSCs), Foxp3+ regulatory T cells (Tregs), regulatory dendritic cells and B regulatory cells are some of the regulatory populations that have been involved in the acute immune response elicited by the parasite. The fact that, during acute infection, MDSCs increase notably in several organs, such as spleen, liver and heart, together with the observation that depletion of those cells can decrease mouse survival to 0%, strongly suggests that MDSCs play a major role during acute T. cruzi infection. Accumulating evidence gained in different settings supports the capacity of MDSCs to interact with cells from both the effector and the regulatory arms of the immune system, shaping the outcome of the response in a very wide range of scenarios that include pathological and physiological processes. In this sense, the aim of the present review is to describe the main knowledge about MDSCs acquired so far, including several crosstalk with other immune populations, which could be useful to gain insight into their role during T. cruzi infection.

Interleukin 10 Polymorphisms as Risk Factors for Progression to Chagas Disease Cardiomyopathy: A Case-Control Study and Meta-Analysis

Background

Chagas disease is a lifelong infection caused by the protozoa Trypanosoma cruzi endemic in Latin-America and emergent worldwide. Decades after primary infection, 20-30% of infected people develop chronic Chagas cardiomyopathy (CCC) while the others remain asymptomatic. CCC pathogenesis is complex but associated with sustained pro-inflammatory response leading to tissue damage. Hence, levels of IL-10 could have a determinant role in CCC etiology. Studies with Latin-American populations have addressed the association of genetic variants of IL-10 and the risk of developing CCC with inconsistent results. We carried out a case control study to explore the association between IL-10-1082G>A (rs18008969), -819C>T (rs1800871), -592A>C (rs1800872) polymorphisms and CCC in a population attending a hospital in Buenos Aires Argentina. Next, a systematic review of the literature and a meta-analysis were conducted combining present and previous studies to further study this association.

Methods

Our case control study included 122 individuals with chronic T. cruzi infection including 64 patients with any degree of CCC and 58 asymptomatic individuals. Genotyping of IL-10 -1082G>A, -819C>T, -592A>C polymorphisms was performed by capillary sequencing of the region spanning the three polymorphic sites and univariate and multivariate statistical analysis was undertaken. Databases in English, Spanish and Portuguese language were searched for papers related to these polymorphisms and Chagas disease up to December 2021. A metanalysis of the selected literature and our study was performed based on the random effect model.

Results

In our cohort, we found a significant association between TT genotype of -819 rs1800871 and AA genotype of -592 rs1800872 with CCC under the codominant (OR=5.00; 95%CI=1.12-23.87 P=0,04) and the recessive models (OR=5.37; 95%CI=1.12-25.68; P=0,03). Of the genotypes conformed by the three polymorphic positions, the homozygous genotype ATA was significantly associated with increased risk of CCC. The results of the meta-analysis of 754 cases and 385 controls showed that the TT genotype of -819C>T was associated with increased CCC risk according to the dominant model (OR=1.13; 95% CI=1.02–1.25; P=0,03).

Conclusion

The genotype TT at -819 rs1800871 contributes to the genetic susceptibility to CCC making this polymorphism a suitable candidate to be included in a panel of predictive biomarkers of disease progression.

Comprehensive analysis of miRNA-mRNA regulatory network and potential drugs in chronic chagasic cardiomyopathy across human and mouse

Background

Chronic chagasic cardiomyopathy (CCC) is the leading cause of heart failure in Latin America and often causes severe inflammation and fibrosis in the heart. Studies on myocardial function and its molecular mechanisms in patients with Chronic chagasic cardiomyopathy are very limited. In order to understand the development and progression of Chronic chagasic cardiomyopathy and find targets for its diagnosis and treatment, the field needs to better understand the exact molecular mechanisms involved in these processes.

Methods

The mRNA microarray datasets GSE84796 (human) and GSE24088 (mouse) were obtained from the Gene Expression Omnibus (GEO) database. Homologous genes between the two species were identified using the online database mining tool Biomart, followed by differential expression analysis, gene enrichment analysis and protein–protein interaction (PPI) network construction. Cytohubba plug-in of Cytoscape software was used to identify Hub gene, and miRNet was used to construct the corresponding miRNA–mRNA regulatory network. miRNA-related databases: miRDB, Targetscan and miRWalk were used to further evaluate miRNAs in the miRNA–mRNA network. Furthermore, Comparative Toxicogenomics Database (CTD) and L1000 Platform were used to identify hub gene-related drugs.

Results

A total of 86 homologous genes were significantly differentially expressed in the two datasets, including 73 genes with high expression and 13 genes with low expression. These differentially expressed genes were mainly enriched in the terms of innate immune response, signal transduction, protein binding, Natural killer cell mediated cytotoxicity, Tuberculosis, Chemokine signaling pathway, Chagas disease and PI3K−Akt signaling pathway. The top 10 hub genes LAPTM5, LCP1, HCLS1, CORO1A, CD48, TYROBP, RAC2, ARHGDIB, FERMT3 and NCF4 were identified from the PPI network. A total of 122 miRNAs were identified to target these hub genes and 30 of them regulated two or more hub genes at the same time. miRDB, Targetscan and miRWalk were further analyzed and screened out hsa-miR-34c-5p, hsa-miR-34a-5p and hsa-miR-16-5p as miRNAs regulating these hub genes. Finally, Progesterone, Flutamide, Nimesulide, Methotrexate and Temozolomide were identified to target these hub genes and might be targeted therapies for Chronic chagasic cardiomyopathy.

Conclusions

In this study, the potential genes associated with Chronic chagasic cardiomyopathy are identified and a miRNA–mRNA regulatory network is constructed. This study explores the molecular mechanisms of Chronic chagasic cardiomyopathy and provides important clues for finding new therapeutic targets.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-01134-3.

The Unsolved Jigsaw Puzzle of the Immune Response in Chagas Disease

Trypanosoma cruzi interacts with the different arms of the innate and adaptive host's immune response in a very complex and flowery manner. The history of host-parasite co-evolution has provided this protozoan with means of resisting, escaping or subverting the mechanisms of immunity and establishing a chronic infection. Despite many decades of research on the subject, the infection remains incurable, and the factors that steer chronic Chagas disease from an asymptomatic state to clinical onset are still unclear. As the relationship between T. cruzi and the host immune system is intricate, so is the amount and diversity of scientific knowledge on the matter. Many of the mechanisms of immunity are fairly well understood, but unveiling the factors that lead each of these to success or failure, within the coordinated response as a whole, requires further research. The intention behind this Review is to compile the available information on the different aspects of the immune response, with an emphasis on those phenomena that have been studied and confirmed in the human host. For ease of comprehension, it has been subdivided in sections that cover the main humoral and cell-mediated components involved therein. However, we also intend to underline that these elements are not independent, but function intimately and concertedly. Here, we summarize years of investigation carried out to unravel the puzzling interplay between the host and the parasite.

Dual role of monocyte-derived dendritic cells in Trypanosoma cruzi infection

Pathogens can cause inflammation when inoculated into the skin. The vector-transmitted protozoan parasite Trypanosoma cruzi induces poor cellular-infiltration and disseminates, causing high mortality in the experimental model. Here, we characterized the inflammatory foci at the parasite inoculation site and secondary lymphoid organs using a murine model. While no macrophages and few neutrophils and monocytes (Mo) were recruited into the skin, T. cruzi infection elicited the mobilization of Ly6C⁺ Mo to draining lymph nodes and spleen. Over time, this population became enriched in CD11b⁺ Ly6C⁺ CD11c⁺ MHCII⁺ CD86⁺ cells resembling inflammatory dendritic cells (DCs). Adoptive transfer of Ly6C⁺ Mo purified from the bone marrow of CD11c-GFP transgenic mice confirmed the monocytic origin of Ly6C⁺ DCs found in the spleen of infected animals. Isolated Mo-derived cells not only produced TNF-α and nitric oxide, but also IL-10 and displayed a poor capacity to induce lymphoproliferation. Ablation of Mo-derived cells by 5-fluorouracil confirmed their dual role during infection, limiting the parasite load by inducible nitric oxide synthase-related mechanisms and negatively affecting the development of anti-parasite T-cell response. This study demonstrated that consistent with their antagonistic properties, these cells not only control the parasite spreading but also its persistence in the host.

Dendritic Cells: A Double-Edged Sword in Immune Responses during Chagas Disease

Dendritic cells (DCs) are the most important member of the antigen presenting cells group due to their ability to recognize antigen at the infection site and their high specialized antigen internalization capacity. These cells have central role in connecting the innate and adaptive immune responses against Trypanosoma cruzi, the causative agent of Chagas disease. These first line defense cells modulate host immune response depending on type, maturation level, cytokine milieu and DC receptor involved in the interactions with T. cruzi, influencing the development of the disease clinic forms. Here, we present a review of DCs-T. cruzi interactions both in human and murine models, pointing out the parasite ability to manipulate DCs activity for the purpose of evading innate immune response and assuring its own survival and persistence.

Bidirectional interactions of NK cells and dendritic cells in immunotherapy: current and future perspective

NK cells and dendritic cells (DC) are innate cellular components that regulate adaptive immune responses in the immune surveillance of cancer and infections. Interactions of NK and DC are bidirectional. In this mini review, we summarized how NK cells regulate immature DC editing and maturation, how DC regulate NK-cell functions reciprocally in the NK-DC crosstalk, and the importance of NK-DC crosstalk in antitumor immunity. Enhancing NK-DC crosstalk by cellular factor(s), antibodies or creating a microenvironment that promote NK activations, DC maturation and NK-DC crosstalk will provide new insights into future development of DC-based immunotherapy.

A flow cytometer-based method to simultaneously assess activity and selectivity of compounds against the intracellular forms of Trypanosoma cruzi

Chagas disease is a major unsolved health issue in Latin America and an emerging threat worldwide. New drugs are urgently needed for chemotherapy as those available (benznidazole and nifurtimox) have variable efficacy and elevated toxicity. Efforts are actually oriented to improve tools and technologies (e.g. transgenic parasites, flow cytometry or image-based systems) for the screening of large numbers of candidate compounds for their activity against Trypanosoma cruzi (T. cruzi). Methods that test drug efficacy and selectivity in the same assay are suitable to accelerate the process of drug discovery. Here, we developed a GFP expressing T. cruzi from a moderate virulence stock and confirmed that the transgenic parasite retained the biological characteristics of the parental strain. With this tool, we established a flow cytometer-based method to simultaneously test drug activity against intracellular amastigotes and toxicity to the host cell. This one-step procedure allows determining the selectivity index of the tested compound in a sensitive and accurate manner even with low infection rates. This method can provide additional information on the interactions between drug, parasites and host cell and could be adapted to other trypanosomatids and protozoa with intracellular multiplication.