transforming-growth-factor-beta and Chagas-Disease

For over 60 years, selenium (Se) has been known as an essential microelement to many biological functions, including cardiovascular homeostasis. This review presents a compilation of studies conducted in the past 20 years related to chronic Chagas disease cardiomyopathy (CCC), caused by

Topics: Chagas Disease; Communicable Diseases; Fibrosis; Heart Failure; Humans; Selenium; Transforming Growth Factor beta; Trypanosoma cruzi

The anti-inflammatory cytokine transforming growth factor beta (TGF-β) plays an important role in Chagas disease (CD), a potentially life-threatening illness caused by

Topics: Animals; Biomarkers; Chagas Disease; Humans; Immunogenetics; Mice; Transforming Growth Factor beta; Trypanosoma cruzi

Transforming growth factor-β (TGF-β) influences the development of myocardiopathy in Chagas disease through regulation of (i) parasite invasion of heart cells, (ii) an intracellular parasite cycle, (iii) inflammation and immune response, (iv) heart fibrosis and remodeling, and (v) gap junction modulation and heart conduction. In this review, we discuss the rationale for developing TGF-β signaling-interfering therapies as adjuvant approaches for the management of the cardiac alterations of Chagas disease-affected patients.

Topics: Animals; Chagas Cardiomyopathy; Chagas Disease; Drug Design; Gap Junctions; Heart Conduction System; Humans; Inflammation; Signal Transduction; Transforming Growth Factor beta; Trypanosoma cruzi

Infection with the protozoan parasite Trypanosoma cruzi leads to Chagas disease, which affects millions of people in Latin America. Infection with T. cruzi cannot be eliminated by the immune system. A better understanding of immune evasion mechanisms is required in order to develop more effective vaccines. During the acute phase, parasites replicate extensively and release immunomodulatory molecules that delay parasite-specific responses mediated by T cells. This immune evasion allows the parasite to spread in the host. In the chronic phase, parasite evasion relies on its replication strategy of hijacking the TGF-β signaling pathway involved in inflammation and tissue regeneration. In this article, the mechanisms of immune evasion described for T. cruzi are reviewed.

Topics: Acute Disease; Antigens, Protozoan; Chagas Disease; Chronic Disease; Host-Parasite Interactions; Humans; Immune Evasion; T-Lymphocytes; Transforming Growth Factor beta; Trypanosoma cruzi

Topics: Adaptive Immunity; Animals; CD4-Positive T-Lymphocytes; CD55 Antigens; Chagas Disease; Host-Parasite Interactions; Humans; Immune Evasion; Immunity, Innate; Interleukin-10; Toll-Like Receptors; Transforming Growth Factor beta; Trypanosoma cruzi

Transforming growth factor beta (TGF-beta) is an important regulator of inflammation, being proinflammatory at low concentrations and anti-inflammatory at high concentrations. As such, TGF-beta might be important in maintaining the balance between control and clearance of infectious organisms on the one hand and prevention of immune-mediated pathology on the other. In this article, Fakhereldin Omer, Jørgen Kurtzhals and Eleanor Riley review the immunoregulatory properties of TGF-beta in the context of parasitic infections. Data from murine malaria infections suggest that TGF-beta modifies the severity of the disease, and a number of potential protective mechanisms are discussed. Evidence is accumulating that TGF-beta is important for the regulation of other host-parasite interactions and that parasites might directly influence TGF-beta-dependent pathways via the synthesis of TGF-beta or TGF-beta-receptor homologues.

Topics: Animals; Chagas Disease; Genetic Variation; Host-Parasite Interactions; Humans; Leishmaniasis; Malaria; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Plasmodium falciparum; Schistosoma mansoni; Schistosomiasis mansoni; Transforming Growth Factor beta; Trypanosoma cruzi

Topics: Animals; Autoimmunity; Chagas Disease; Cytokines; Disease Models, Animal; Humans; Interleukin-10; Mice; T-Lymphocytes; Transforming Growth Factor beta

Topics: Animals; CD8-Positive T-Lymphocytes; Chagas Disease; Immunologic Memory; Interleukin-10; Liver; Mice; Models, Immunological; Receptors, Aryl Hydrocarbon; T-Lymphocytes, Regulatory; Th1 Cells; Transforming Growth Factor beta; Trypanosoma cruzi

Chagasic cardiomyopathy (CC) is the main manifestation of Chagas Disease (CD). CC is a progressive dysfunctional illness, in which transforming growth factor beta (TGF-β) plays a central role in fibrogenesis and hypertrophy. In the present study, we tested in a three-dimensional (3D) model of cardiac cells culture (named cardiac spheroids), capable of mimicking the aspects of fibrosis and hypertrophy observed in CC, the role of TGF-β pathway inhibition in restoring extracellular matrix (ECM) balance disrupted by T. cruzi infection. Treatment of T. cruzi-infected cardiac spheroids with SB 431542, a selective inhibitor of TGF-β type I receptor, resulted in a reduction in the size of spheroids, which was accompanied by a decrease in parasite load and in fibronectin expression. The inhibition of TGF-β pathway also promoted an increase in the activity of matrix metalloproteinase (MMP)-2 and a decrease in tissue inhibitor of matrix metalloproteinase (TIMP)-1 expression, which may be one of the mechanisms regulating extracellular matrix remodeling. Therefore, our study provides new insights into the molecular mechanisms by which inhibition of TGF-β signaling reverts fibrosis and hypertrophy generated by T. cruzi during CC and also highlights the use of cardiac spheroids as a valuable tool for the study of fibrogenesis and anti-fibrotic compounds.

Topics: Benzamides; Cardiomyopathies; Chagas Disease; Dioxoles; Extracellular Matrix; Fibronectins; Gene Expression Regulation; Heart; Humans; Matrix Metalloproteinase 2; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type I; Receptors, Transforming Growth Factor beta; Spheroids, Cellular; Tissue Inhibitor of Metalloproteinase-1; Transforming Growth Factor beta; Trypanosoma cruzi

Transforming growth factor

Topics: Adult; Aged; Brazil; Chagas Disease; Female; Humans; Male; Middle Aged; Polymorphism, Single Nucleotide; Transforming Growth Factor beta

Studies developed by our group in the last years have shown the involvement of TGF-β in acute and chronic Chagas heart disease, with elevated plasma levels and activated TGF-β cell signaling pathway as remarkable features of patients in the advanced stages of this disease, when high levels of cardiac fibrosis is present. Imbalance in synthesis and degradation of extracellular matrix components is the basis of pathological fibrosis and TGF-β is considered as one of the key regulators of this process. In the present study, we investigated the activity of the TGF-β signaling pathway, including receptors and signaling proteins activation in the heart of animals experimentally infected with Trypanosoma cruzi during the period that mimics the acute phase of Chagas disease. We observed that T. cruzi-infected animals presented increased expression of TGF-β receptors. Overexpression of receptors was followed by an increased phosphorylation of Smad2/3, p38 and ERK. Furthermore, we correlated these activities with cellular factors involved in the fibrotic process induced by TGF-β. We observed that the expression of collagen I, fibronectin and CTGF were increased in the heart of infected animals on day 15 post-infection. Correlated with the increased TGF-β activity in the heart, we found that serum levels of total TGF-β were significantly higher during acute infection. Taken together, our data suggest that the commitment of the heart associates with increased activity of TGF-β pathway and expression of its main components. Our results, confirm the importance of this cytokine in the development and maintenance of cardiac damage caused by T. cruzi infection.

Topics: Animals; Chagas Disease; Disease Models, Animal; Extracellular Matrix; Male; Mice; Myocardium; Receptors, Transforming Growth Factor beta; Signal Transduction; Transforming Growth Factor beta; Trypanosoma cruzi; Up-Regulation

Transforming growth factor beta (TGF-β) cytokine is involved in Chagas disease establishment and progression. Since Trypanosoma cruzi can modulate host cell receptors, we analysed the TGF-β receptor type II (TβRII) expression and distribution during T. cruzi - cardiomyocyte interaction. TβRII immunofluorescent staining revealed a striated organization in cardiomyocytes, which was co-localized with vinculin costameres and enhanced (38%) after TGF-β treatment. Cytochalasin D induced a decrease of 45·3% in the ratio of cardiomyocytes presenting TβRII striations, demonstrating an association of TβRII with the cytoskeleton. Western blot analysis showed that cytochalasin D significantly inhibited Smad 2 phosphorylation and fibronectin stimulation after TGF-β treatment in cardiomyocytes. Trypanosoma cruzi infection elicited a decrease of 79·8% in the frequency of cardiomyocytes presenting TβRII striations, but did not interfere significantly in its expression. In addition, T. cruzi-infected cardiomyocytes present a lower response to exogenous TGF-β, showing no enhancement of TβRII striations and a reduction of phosphorylated Smad 2, with no significant difference in TβRII expression when compared to uninfected cells. Together, these results suggest that the co-localization of TβRII with costameres is important in activating the TGF-β signalling cascade, and that T. cruzi-derived cytoskeleton disorganization could result in altered or low TGF-β response in infected cardiomyocytes.

Topics: Animals; Cells, Cultured; Chagas Disease; Costameres; Gene Expression Regulation; Host-Parasite Interactions; Mice; Myocytes, Cardiac; Protein Serine-Threonine Kinases; Protein Transport; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Signal Transduction; Transforming Growth Factor beta; Trypanosoma cruzi

Trypanosoma cruzi, the etiological agent of Chagas' disease, induces a persistent inflammatory response. Macrophages are a first line cell phenotype involved in the clearance of infection. Upon parasite uptake, these cells increase inflammatory mediators like NO, TNF-α, IL-1β and IL-6, leading to parasite killing. Although desired, inflammatory response perpetuation and exacerbation may lead to tissue damage. Peroxisome proliferator-activated receptors (PPARs) are ligand-dependent nuclear transcription factors that, besides regulating lipid and carbohydrate metabolism, have a significant anti-inflammatory effect. This is mediated through the interaction of the receptors with their ligands. PPARγ, one of the PPAR isoforms, has been implicated in macrophage polarization from M1, the classically activated phenotype, to M2, the alternatively activated phenotype, in different models of metabolic disorders and infection. In this study, we show for the first time that, besides PPARγ, PPARα is also involved in the in vitro polarization of macrophages isolated from T. cruzi-infected mice. Polarization was evidenced by a decrease in the expression of NOS2 and proinflammatory cytokines and the increase in M2 markers like Arginase I, Ym1, mannose receptor and TGF-β. Besides, macrophage phagocytic activity was significantly enhanced, leading to increased parasite load. We suggest that modulation of the inflammatory response by both PPARs might be due, at least in part, to a change in the profile of inflammatory macrophages. The potential use of PPAR agonists as modulators of overt inflammatory response during the course of Chagas' disease deserves further investigation.

Topics: Animals; Arginase; beta-N-Acetylhexosaminidases; Blotting, Western; Cells, Cultured; Chagas Disease; Cytokines; Host-Pathogen Interactions; Inflammation Mediators; Lectins; Ligands; Macrophage Activation; Macrophages; Male; Mice, Inbred BALB C; Microscopy, Fluorescence; Nitric Oxide Synthase Type II; Phagocytosis; PPAR alpha; PPAR gamma; Prostaglandin D2; Pyrimidines; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Transforming Growth Factor beta; Trypanosoma cruzi

This study evaluates the effect of Trypanosoma cruzi biotherapy 17dH (BIOT) on mice of different ages, infected with the protozoa concerned.. Performing a blind, controlled, randomized by drawing experiment, 110 animals four or eight-week-old, Swiss, male mice were divided into infected control treated hydroalcoholic 7% (CI-4 = 34 or CI-8 = 21 animals) and infected control treated with biotherapy 17dH-0.2 mL/animal/20 consecutive days/oral regimen (BIOT-4 = 33 or BIOT-8 = 21 animals). Animals were inoculated intraperitoneally with 1400 trypomastigote, T. cruzi Y-strain. Parasitological, immunological and histopathologic parameters were evaluated statistically, using Statistica-8.0 and R 3.0.2 program to analysis of survival. The study was approved by the Ethics Committee for Animal Experimentation/UEM.. Four-week-old mice showed no statistical difference in parasitemia (P = 0.5718) between the treated and control group. Eight-week-old mice from the treated group had a higher parasite peak (P = 0.0424) and higher parasitemia (P < 0.005) than the control. To both groups of 4 and 8 weeks of age, treated or untreated, survival of mice was higher in the treated group than in the control, although it was not statistically significant (p-value = 0.32, 0.55 respectively). Four-week-old mice displayed a spleen section with a number of amastigote nests significantly higher in BIOT-4 than CI-4 (P = 0.01). In eight-week-old mice the number of amastigote nests (P < 0.001) and inflammatory foci (P < 0.06-10% significance) in the liver section were smaller in BIOT-8 than CI-8. Spleen giant cells were significantly higher in CI-8 than in BIOT-8 (P < 0.01). Eight-week-old animals treated with biotherapy showed higher parasitemia and lower tissue parasitism. Opposite pattern was observed in four-week-old animals.. There is a difference of high diluted medication effect in four and eight-week-old mice. In the group of animals 8 weeks the immunomodulatory effect seems to have been higher. Hence, treatment with the medicine produced from T. cruzi modulates the inflammatory response with increased apoptosis and decreased serum levels of TGF-β.

Topics: Animals; Biological Therapy; Chagas Disease; Homeopathy; Inflammation; Liver; Male; Mice; Transforming Growth Factor beta; Trypanosoma cruzi

Trypanosoma cruzi causes neuronal myenteric depopulation compromising intestinal function.. The purpose of this study was to evaluate the influence of moderate physical exercise on NADH diaphorase (NADH-d)-positive neurons in the myenteric plexus and intestinal wall of the colon in mice infected with T. cruzi.. Forty 30-day-old male Swiss mice were divided into the following groups: trained infected (TI), sedentary infected (SI), trained control (TC), and sedentary control. The TC and TI groups were subjected to a moderate physical exercise program on a treadmill for 8 weeks. Three days after finishing physical exercise, the TI and SI groups were intraperitoneally inoculated with 1,300 blood trypomastigotes of the Y strain of Trypanosoma cruzi. Parasitemia was evaluated from days 4 to 61 after inoculation. On day 75 of infection, myenteric neurons in the colon were quantified (NADH-d), and inflammatory foci were counted. Tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β) levels were evaluated in plasma. The results were compared using analysis of variance and the Kruskal-Wallis test at a 5 % significance level.. Moderate physical exercise reduced the parasite peak on day 8 of infection (p = 0.0132) and total parasitemia (p = 0.0307). It also prevented neuronal depopulation (p < 0.01), caused hypertrophy of these cells (p < 0.05), prevented the formation of inflammatory foci (p < 0.01), and increased the synthesis of TNF-α (p < 0.01) and TGF-β (p > 0.05).. These results reinforce the therapeutic benefits of moderate physical exercise for T. cruzi infection.

Topics: Animals; Chagas Disease; Colon; Dihydrolipoamide Dehydrogenase; Disease Models, Animal; Hypertrophy; Inflammation Mediators; Male; Mice; Myenteric Plexus; Neurons; Physical Exertion; Time Factors; Transforming Growth Factor beta; Trypanosoma cruzi; Tumor Necrosis Factor-alpha

The recent increase in immigration of people from areas endemic for Chagas disease (Trypanosoma cruzi) to the United States and Europe has raised concerns about the transmission via blood transfusion and organ transplants in these countries. Infection by these pathways occurs through blood trypomastigotes (BT), and these forms of T. cruzi are completely distinct of metacyclic trypomastigotes (MT), released by triatomine vector, in relation to parasite-host interaction. Thus, research comparing infection with these different infective forms is important for explaining the potential impacts on the disease course. Here, we investigated tissue parasitism and relative mRNA expression of cytokines, chemokines, and chemokine receptors in the heart during acute infection by MT or BT forms in dogs. BT-infected dogs presented a higher cardiac parasitism, increased relative mRNA expression of pro-inflammatory and immunomodulatory cytokines and of the chemokines CCL3/MIP-1α, CCL5/RANTES, and the chemokine receptor CCR5 during the acute phase of infection, as compared to MT-infected dogs. These results suggest that infection with BT forms may lead to an increased immune response, as revealed by the cytokines ratio, but this kind of immune response was not able to control the cardiac parasitism. Infection with the MT form presented an increase in the relative mRNA expression of IL-12p40 as compared to that of IL-10 or TGF-β1. Correlation analysis showed increased relative mRNA expression of IFN-γ as well as IL-10, which may be an immunomodulatory response, as well as an increase in the correlation of CCL5/RANTES and its CCR5 receptor. Our findings revealed a difference between inoculum sources of T. cruzi, as vectorial or transfusional routes of T. cruzi infection may trigger distinct parasite-host interactions during the acute phase, which may influence immunopathological aspects of Chagas disease.

Topics: Animals; Chagas Disease; Chemokine CCL3; Chemokine CCL5; Cytokines; Disease Models, Animal; Dogs; Female; Heart; Host-Parasite Interactions; Interferon-gamma; Interleukin-10; Interleukin-12 Subunit p40; Male; Myocardium; Receptors, CCR5; RNA, Messenger; Transforming Growth Factor beta; Trypanosoma cruzi

Chagas disease was discovered more than a hundred years ago, but its pathogenesis is still not completely understood. Autoimmunity is one of the mechanisms shown to contribute to its pathogenesis, which may indicate an important participation of B lymphocytes. Patients with Chagas disease have shown increased percentage of B cells producing IL-10. However, there are no reports of the phenotypic markers of B cells producing IL-10 in patients with Chagas disease. For the first time in the literature, we evaluated the phenotypic profile of distinct markers of B cells from peripheral blood of noninfected individuals and patients with Chagas disease. Our results showed that patients with Chagas disease had a higher expression of CD21 and CD24 on the surface of CD19+ B cells, while CD43 and CD23 were expressed equally in all groups. Moreover, the expression of MHC-II (HLA-DR), CD80, CD86, caspase-3, granzyme B and intracellular IL-10 and TGF-β by CD19+ B cells was higher in patients with Chagas disease. The results of IL-10 production within CD19+ CD5+ CD1d+ B cells showed a higher percentage of this cytokine in patients with Chagas disease. Thus, our data bring a new knowledge about distinct markers of B cells in immune responses of Chagas disease.

Topics: Adult; Antigens, CD; B-Lymphocytes; Biomarkers; Caspase 3; Chagas Disease; Female; HLA-DR Antigens; Humans; Immunophenotyping; Interleukin-10; Male; Middle Aged; Transforming Growth Factor beta; Trypanosoma cruzi

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, affects several million people in Latin America. Myocarditis, observed during both the acute and chronic phases of the disease, is characterized by an inflammatory mononuclear cell infiltrate that includes CD4(+) T cells. It is known that Th1 cytokines help to control infection. The role that Treg and Th17 cells may play in disease outcome, however, has not been completely elucidated. We performed a comparative study of the dynamics of CD4(+) T cell subsets after infection with the T. cruzi Y strain during both the acute and chronic phases of the disease using susceptible BALB/c and non-susceptible C57BL/6 mice infected with high or low parasite inocula. During the acute phase, infected C57BL/6 mice showed high levels of CD4(+) T cell infiltration and expression of Th1 cytokines in the heart associated with the presence of Treg cells. In contrast, infected BALB/c mice had a high heart parasite burden, low heart CD4(+) T cell infiltration and low levels of Th1 and inflammatory cytokines, but with an increased presence of Th17 cells. Moreover, an increase in the expression of IL-6 in susceptible mice was associated with lethality upon infection with a high parasite load. Chronically infected BALB/c mice continued to present higher parasite burdens than C57BL/6 mice and also higher levels of IFN-γ, TNF, IL-10 and TGF-β. Thus, the regulation of the Th1 response by Treg cells in the acute phase may play a protective role in non-susceptible mice irrespective of parasite numbers. On the other hand, Th17 cells may protect susceptible mice at low levels of infection, but could, in association with IL-6, be pathogenic at high parasite loads.

Topics: Animals; CD4-Positive T-Lymphocytes; Chagas Disease; Cytokines; Female; Flow Cytometry; Fluorescent Antibody Technique; Interferon-gamma; Interleukin-10; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Real-Time Polymerase Chain Reaction; Transforming Growth Factor beta; Trypanosoma cruzi

This study evaluated the influence of moderate physical exercise on the myenteric neurons in the colonic intestinal wall of mice that had been infected with Trypanosoma cruzi. Parasitology and immunological aspects of the mice were considered. Forty-day-old male Swiss mice were divided into four groups: Trained Infected (TI), Sedentary Infected (SI), Trained Control (TC), and Sedentary Control (SC). The TC and TI were subjected to a moderate physical exercise program on a treadmill for 8 weeks. Three days after finishing exercise, the TI and SI groups were inoculated with 1,300 blood trypomastigotes of the Y strain-T. cruzi. After 75 days of infection results were obtained. Kruskal-Wallis or Analyze of variance (Tukey post hoc test) at 5% level of significance was performed. Moderate physical exercise reduced both the parasite peak (day 8 of infection) and total parasitemia compared with the sedentary groups (P < 0.05). This activity also contributed to neuronal survival (P < 0.05). Exercise caused neuronal hypertrophy (P < 0.05) and an increase in the total thickness of the intestinal wall (P < 0.05). The TI group exhibited an increase in the number of intraepithelial lymphocytes (P > 0.05). In trained animals, the number of goblet cells was reduced compared with sedentary animals (P < 0.05). Physical exercise prevented the formation of inflammatory foci in the TI group (P < 0.05) and increased the synthesis of TNF-α (P < 0.05) and TGF-β (P > 0.05). The present results demonstrated the benefits of moderate physical exercise, and reaffirmed the possibility of that it may contribute to improving clinical treatment in Chagas' disease patients.

Topics: Animals; Cell Survival; Chagas Disease; Colon; Disease Models, Animal; Male; Mice; Myenteric Plexus; Neurons; Parasitemia; Physical Conditioning, Animal; Transforming Growth Factor beta; Trypanosoma cruzi; Tumor Necrosis Factor-alpha

The innate immune system is the first mechanism of vertebrate defense against pathogen infection. In this study, we present evidence for a novel immune evasion mechanism of Trypanosoma cruzi, mediated by host cell plasma membrane-derived vesicles. We found that T. cruzi metacyclic trypomastigotes induced microvesicle release from blood cells early in infection. Upon their release, microvesicles formed a complex on the T. cruzi surface with the complement C3 convertase, leading to its stabilization and inhibition, and ultimately resulting in increased parasite survival. Furthermore, we found that TGF-β-bearing microvesicles released from monocytes and lymphocytes promoted rapid cell invasion by T. cruzi, which also contributed to parasites escaping the complement attack. In addition, in vivo infection with T. cruzi showed a rapid increase of microvesicle levels in mouse plasma, and infection with exogenous microvesicles resulted in increased T. cruzi parasitemia. Altogether, these data support a role for microvesicles contributing to T. cruzi evasion of innate immunity.

Topics: Animals; Cell Membrane; Cells, Cultured; Chagas Disease; Complement C3-C5 Convertases; Cytoplasmic Vesicles; Erythrocytes; Host-Pathogen Interactions; Humans; Immune Evasion; Immunity, Innate; Lymphocytes; Mice; Mice, Inbred BALB C; Monocytes; Transforming Growth Factor beta; Trypanosoma cruzi

The protozoan parasite Trypanosoma cruzi is the etiologic agent of Chagas disease, a neglected tropical infection that affects millions of people in the Americas. Current chemotherapy relies on only two drugs that have limited efficacy and considerable side effects. Therefore, the development of new and more effective drugs is of paramount importance. Although some host cellular factors that play a role in T. cruzi infection have been uncovered, the molecular requirements for intracellular parasite growth and persistence are still not well understood. To further study these host-parasite interactions and identify human host factors required for T. cruzi infection, we performed a genome-wide RNAi screen using cellular microarrays of a printed siRNA library that spanned the whole human genome. The screening was reproduced 6 times and a customized algorithm was used to select as hits those genes whose silencing visually impaired parasite infection. The 162 strongest hits were subjected to a secondary screening and subsequently validated in two different cell lines. Among the fourteen hits confirmed, we recognized some cellular membrane proteins that might function as cell receptors for parasite entry and others that may be related to calcium release triggered by parasites during cell invasion. In addition, two of the hits are related to the TGF-beta signaling pathway, whose inhibition is already known to diminish levels of T. cruzi infection. This study represents a significant step toward unveiling the key molecular requirements for host cell invasion and revealing new potential targets for antiparasitic therapy.

Topics: Animals; Biomarkers; Cells, Cultured; Chagas Disease; Gene Expression Profiling; Genome, Human; Haplorhini; High-Throughput Screening Assays; Host-Parasite Interactions; Humans; Kidney; Oligonucleotide Array Sequence Analysis; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; RNA, Messenger; RNA, Small Interfering; Transforming Growth Factor beta; Trypanosoma cruzi

Gap junction connexin-43 (Cx43) molecules are responsible for electrical impulse conduction in the heart and are affected by transforming growth factor-beta (TGF-beta). This cytokine increases during Trypanosoma cruzi infection, modulating fibrosis and the parasite cell cycle. We studied Cx43 expression in cardiomyocytes exposed or not to TGF-beta T. cruzi, or SB-431542, an inhibitor of TGF-beta receptor type I (ALK-5). Cx43 expression was also examined in hearts with dilated cardiopathy from chronic Chagas disease patients, in which TGF-beta signalling had been shown previously to be highly activated. We demonstrated that TGF-beta treatment induced disorganised gap junctions in non-infected cardiomyocytes, leading to a punctate, diffuse and non-uniform Cx43 staining. A similar pattern was detected in T. cruzi-infected cardiomyocytes concomitant with high TGF-beta secretion. Both results were reversed if the cells were incubated with SB-431542. Similar tests were performed using human chronic chagasic patients and we confirmed a down-regulation of Cx43 expression, an altered distribution of plaques in the heart and a significant reduction in the number and length of Cx43 plaques, which correlated negatively with cardiomegaly. We conclude that elevated TGF-beta levels during T. cruzi infection promote heart fibrosis and disorganise gap junctions, possibly contributing to abnormal impulse conduction and arrhythmia that characterise severe cardiopathy in Chagas disease.

Topics: Adult; Animals; Benzamides; Chagas Disease; Connexin 43; Dioxoles; Female; Fluorescent Antibody Technique; Gap Junctions; Humans; Immunohistochemistry; Male; Mice; Microscopy, Confocal; Middle Aged; Myocytes, Cardiac; Receptors, Transforming Growth Factor beta; Transforming Growth Factor beta

Control of the acute phase of Trypanosoma cruzi infection is critically dependent on cytokine-mediated macrophage activation to intracellular killing, natural killer (NK) cells, CD4(+) T cells, CD8(+) T cells and B cells. Cell-mediated immunity in T. cruzi infection is also modulated by cytokines, but in addition to parasite-specific responses, autoimmunity can be also triggered. Importantly, cytokines may also play a role in the cell-mediated immunity of infected subjects. Here we studied the role of cytokines in the regulation of innate and adaptive immunity during the acute phase of T. cruzi infection in Wistar rats. Melatonin is an effective regulator of the immune system. Macrophages and T lymphocytes, which have melatonin receptors, are target cells for the immunomodulatory function of melatonin. In this paper melatonin was orally given via two protocols: prior to and concomitant with infection. Both treatments were highly effective against T. cruzi with enhanced action for the concomitant treatment. The data suggest an up-regulation of the TH-1 immune response as all analyzed parameters, interleukin (IL)-4, IL-10, transforming growth factor-beta1 and splenocyte proliferation, displayed reduced levels as compared with the untreated counterparts. However, the direct effects of melatonin on immune cells have not been fully investigated during T. cruzi infection. We conclude that in light of the current results, melatonin exerted important therapeutic benefits through its immune regulatory effects.

Topics: Analysis of Variance; Animals; Chagas Disease; Concanavalin A; Cytokines; Immunity, Active; Immunity, Innate; Interleukin-10; Interleukin-4; Macrophages; Melatonin; Parasitemia; Rats; Rats, Wistar; Th1 Cells; Th2 Cells; Transforming Growth Factor beta; Trypanosoma cruzi

The antiinflammatory cytokine transforming growth factor beta (TGF-beta) plays an important role in Chagas disease, a parasitic infection caused by the protozoan Trypanosoma cruzi. In the present study, we show that SB-431542, an inhibitor of the TGF-beta type I receptor (ALK5), inhibits T. cruzi-induced activation of the TGF-beta pathway in epithelial cells and in cardiomyocytes. Further, we demonstrate that addition of SB-431542 greatly reduces cardiomyocyte invasion by T. cruzi. Finally, SB-431542 treatment significantly reduces the number of parasites per infected cell and trypomastigote differentiation and release. Taken together, these data further confirm the major role of the TGF-beta signaling pathway in both T. cruzi infection and T. cruzi cell cycle completion. Our present data demonstrate that small inhibitors of the TGF-beta signaling pathway might be potential pharmacological tools for the treatment of Chagas disease.

Topics: Animals; Apoptosis; Benzamides; Cell Cycle; Cells, Cultured; Chagas Disease; Chlorocebus aethiops; Dioxoles; Epithelial Cells; Mice; Myocytes, Cardiac; Receptors, Transforming Growth Factor beta; Signal Transduction; Transforming Growth Factor beta; Trypanosoma cruzi; Vero Cells

Infection with the protozoan parasite Trypanosoma cruzi leads to chronic infection, with parasite persistence primarily in muscle tissue. CD8(+) T cells isolated from muscle tissue of T. cruzi-infected mice display decreased production of IFN-gamma in response to T cell receptor engagement. The expression of TGF-beta at the site of CD8(+) T cell dysfunction and parasite persistence suggested that this immunoregulatory cytokine might play a role in these processes. Mice expressing a T cell-specific dominant negative TGF-beta receptor type II (DNRII) were therefore infected with T. cruzi. Infection of DNRII mice resulted in massive CD8(+) T cell proliferation, leading to increased numbers but decreased frequencies of antigen-specific CD8(+) T cells in the spleen compared to wild-type mice. However, TGF-beta unresponsiveness failed to restore effector functions of CD8(+) T cells isolated from muscle tissue. Histological examination of skeletal muscle from T. cruzi-infected DNRII mice revealed an extensive cellular infiltrate, and DNRII mice displayed higher susceptibility to infection. Overall, while TGF-beta does not appear to be responsible for CD8(+) T cell unresponsiveness in peripheral tissue in T. cruzi-infected mice, these data suggest a role for TGF-beta in control of immunopathology in response to T. cruzi infection.

Topics: Animals; CD8-Positive T-Lymphocytes; Cells, Cultured; Chagas Disease; Disease Models, Animal; Mice; Mice, Inbred C57BL; Mice, Knockout; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Transforming Growth Factor beta

Calomys callosus, a sylvatic reservoir of Trypanosoma cruzi, when infected with the Colombian strain (Biodeme Type III, T. cruzi I ) develops necrotic-inflammatory lesions and intense early fibrogenesis in the heart and skeletal muscles, that spontaneously regress. Participation of pro-inflammatory and pro-fibrogenic cytokines, such as tumor necrosis factor-alpha (TNF-alpha), gamma interferon (IFN-gamma) , and tumor growth factor-beta (TGF-beta), in the pathogenesis of the lesions is herein studied. Eighty C. callosus weighing 20 to 30 g were used. Seventy of them were inoculated with the Colombian strain (10(5) blood forms) and 10 were maintained as intact non-infected controls. After infection, C. callosus were sacrificed at different time-points from 15 to 70 days. The heart and skeletal muscle were processed for histopathology and cryopreserved for immunohistochemistry. Early necrotic lesions of parasitized skeletal muscle and myocardium with intense inflammatory lesions were present. Search for the in situ presence of TNF-alpha and IFN-gamma, was performed using rat-IgG anti-mouse antibodies against these cytokines. For the in situ search of TGF-beta, rabbit IgG anti-mouse antibodies were used. Immunolabeling of the cytokines in tissues of infected C. callosus was successful. The cytokines TNF-alpha, IFN-gamma , and TGF-beta were detected in the cytoplasm of macrophages and in the necrotic material from 15 to 45 days post-infection, decreasing their intensity until complete disappearance by the 65th day, which correlated with subsiding histopathological lesions. These findings suggest the participation of these cytokines in the control of parasite multiplication, in the development of an early fibrogenesis and in the regression of fibrotic-inflammatory lesions observed in C. callosus.

Topics: Animals; Chagas Disease; Cytokines; Fibrosis; Immunohistochemistry; Interferon-gamma; Male; Muscle, Skeletal; Myocardium; Rodentia; Transforming Growth Factor beta; Trypanosoma cruzi; Tumor Necrosis Factor-alpha

The cytokine transforming growth factor-beta (TGF-beta) plays various functions in the control of Trypanosoma cruzi infectivity and in the progression of Chagas' disease. When we immunostained T. cruzi-infected cardiomyocytes (after either in vivo or in vitro infections) for TGF-beta, we observed stronger immunoreactivity in parasites than in host cells. TGF-beta immunoreactivity evolved during parasite cycle progression, with intense staining in amastigotes versus very faint staining in trypomastigotes. TGF-beta was present on the surface of amastigotes, in the flagellar pocket, and in intraparasitic vesicles as revealed by electron microscopy. However, no ortholog TGF-beta gene could be identified in the genome of T. cruzi by in silico analysis or by extensive polymerase chain reaction and reverse transcriptase-polymerase chain reaction studies. Immunoreactive TGF-beta was most probably taken up by the parasite from the host cell cytoplasm because such an internalization process of biotinylated TGF-beta could be observed in axenic amastigotes in vitro. These observations represent the first example of a novel mechanism by which a primitive unicellular protozoan can use host cell TGF-beta to control its own intracellular life cycle.

Topics: Actins; Animals; Cells, Cultured; Chagas Disease; Embryo, Mammalian; Embryo, Nonmammalian; Fluorescein-5-isothiocyanate; Fluorescent Antibody Technique, Indirect; Fluorescent Dyes; Immunohistochemistry; Indoles; Life Cycle Stages; Mice; Microscopy, Confocal; Myocytes, Cardiac; Phalloidine; Recombinant Proteins; Rhodamines; Time Factors; Transforming Growth Factor beta; Trypanosoma cruzi

The conditions and mechanisms of congenital transmission of Trypanosoma cruzi remain largely unknown. In the present study, we compared the parasitic loads and the immune responses of pregnant T. cruzi-infected women who transmitted parasites to their fetus ("M+B+ mothers") with those of such women who did not transmit parasites to their fetus ("M+B- mothers"). M+B+ mothers had a higher frequency of positive results of hemoculture for T. cruzi than did M+B- mothers, in association with depressed production of parasite-specific interferon- gamma by blood cells that persisted after delivery. In contrast, the production of interleukin (IL)-2, IL-4, and IL-10 and transforming growth factor- beta 1 was similar between both groups of infected mothers, after stimulation with T. cruzi lysate. Flow cytometric analysis showed that T cells and monocytes of M+B+ mothers were less activated than were those of M+B- mothers. Altogether, these results indicate that congenital transmission of T. cruzi is associated with high parasitic loads and peripheral deficient immunological responses in mothers.

Topics: Animals; Chagas Disease; Female; Flow Cytometry; Humans; Infant, Newborn; Infectious Disease Transmission, Vertical; Interferon-gamma; Interleukins; Parasitemia; Pregnancy; Transforming Growth Factor beta; Trypanosoma cruzi

Trypanosoma cruzi proteinases are involved in host cell invasion in human patients and in mouse models. In mice, murine alpha(2)-macroglobulin (MAM) and murinoglobulin are circulating plasma proteinase inhibitors that also have important roles in inflammation and immune modulation. To define their role in experimental Chagas disease, we investigated the susceptibility to T. cruzi infection of mice that are deficient only in alpha2-macroglobulins (AM-KO) or in both MAM and monomeric murinoglobulin-1 (MM-KO), relative to the wild type (WT). Despite the high parasite load, parasitemia was lower in AM-KO and MM-KO mice than in WT mice. Nevertheless, we observed a significantly higher parasite load in the hearts of AM-KO and MM-KO mice, i.e., more amastigote nests and inflammatory infiltrates than in WT mice. This result demonstrates a protective role for MAM in the acute phase of murine T. cruzi infection. We further demonstrated in vitro that human alpha2-macroglobulins altered the trypomastigote morphology and motility in a dose-dependent way, and that also impaired T. cruzi invasion in cardiomyocytes. Finally, we demonstrated that the levels of transforming growth factor beta in AM-KO mice increased significantly in the third week postinfection, concomitant with high amastigote burden and important fibrosis. Combined, these in vivo and in vitro findings demonstrate that the MAM contribute to the resistance of mice to acute myocarditis induced by experimental T. cruzi infection.

Topics: alpha-Macroglobulins; Animals; Chagas Cardiomyopathy; Chagas Disease; Endopeptidases; Female; Fibrosis; Humans; In Vitro Techniques; Mice; Mice, Inbred C57BL; Mice, Knockout; Myocardium; Protease Inhibitors; Serum Globulins; Transforming Growth Factor beta; Trypanosoma cruzi

Infection with Trypanosoma cruzi causes a strong inflammatory reaction at the inoculation site and, later, in the myocardium. The present study investigates the role of cytokines as modulators of T. cruzi-induced chemokine expression in vivo and in vitro. In macrophage cultures, although the stimulation with interferon (IFN)-gamma increases the expression of IP-10, it blocks KC expression. Tumor necrosis factor (TNF)-alpha, on the other hand, potentiates KC, IP-10, macrophage inflammatory protein-1alpha, and JE/monocyte chemotatic protein-1 expression. Interleukin-10 and transforming growth factor-beta inhibited almost all chemokines tested. The role of IFN-gamma and TNF-alpha in chemokine modulation during infection was investigated in T. cruzi-infected IFN-gamma-deficient (GKO) or TNF-R1/p55-deficient (p55-/-) mice. The expression of chemokines detected in the inoculation site correlated with the infiltrating cell type observed. Although GKO mice had a delayed and intense neutrophilic infiltrate correlating with the expression of KC and macrophage inflammatory protein-2, none of the above was observed in p55-/- mice. The detection of infiltrating T cells, Mig, and IP-10 in the myocardium was observed in wild-type and p55-/-, but not in GKO mice. Together, these results suggest that the regulatory roles of IFN-gamma and TNF-alpha on chemokine expression may play a crucial role in the modulation of the inflammatory response during T. cruzi infection and mediate resistance to infection.

Topics: Animals; Antigens, CD; Cell Movement; Chagas Disease; Chemokine CXCL10; Chemokine CXCL9; Chemokines; Chemokines, CXC; Female; Immunophenotyping; Interferon-gamma; Interleukin-10; Lymphocytes; Macrophages; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Myocardium; Peritonitis; Receptors, Tumor Necrosis Factor; Receptors, Tumor Necrosis Factor, Type I; RNA, Messenger; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

After apoptosis, phagocytes prevent inflammation and tissue damage by the uptake and removal of dead cells. In addition, apoptotic cells evoke an anti-inflammatory response through macrophages. We have previously shown that there is intense lymphocyte apoptosis in an experimental model of Chagas' disease, a debilitating cardiac illness caused by the protozoan Trypanosoma cruzi. Here we show that the interaction of apoptotic, but not necrotic T lymphocytes with macrophages infected with T. cruzi fuels parasite growth in a manner dependent on prostaglandins, transforming growth factor-beta (TGF-beta) and polyamine biosynthesis. We show that the vitronectin receptor is critical, in both apoptotic-cell cytoadherence and the induction of prostaglandin E2/TGF-beta release and ornithine decarboxylase activity in macrophages. A single injection of apoptotic cells in infected mice increases parasitaemia, whereas treatment with cyclooxygenase inhibitors almost completely ablates it in vivo. These results suggest that continual lymphocyte apoptosis and phagocytosis of apoptotic cells by macrophages have a role in parasite persistence in the host, and that cyclooxygenase inhibitors have potential therapeutic application in the control of parasite replication and spread in Chagas' disease.

Topics: Amino Acid Chloromethyl Ketones; Animals; Apoptosis; Cells, Cultured; Chagas Disease; Cysteine Proteinase Inhibitors; Dinoprostone; Macrophages; Male; Mice; Mice, Inbred BALB C; Necrosis; Phagocytosis; Putrescine; Receptors, Vitronectin; T-Lymphocytes; Transforming Growth Factor beta; Trypanosoma cruzi

Expression of functional transforming growth factor beta (TGF-beta) receptors (TbetaR) is required for the invasion of mammalian cells by the protozoan parasite Trypanosoma cruzi. However, the precise role of this host cell signaling complex in T. cruzi infection is unknown. To investigate the role of the TGF-beta signaling pathway, infection levels were studied in the mink lung epithelial cell lines JD1, JM2, and JM3. These cells express inducible mutant TbetaR1 proteins that cannot induce growth arrest in response to TGF-beta but still transmit the signal for TGF-beta-dependent gene expression. In the absence of mutant receptor expression, trypomastigotes invaded the cells at a low level. Induction of the mutant receptors caused an increase in infection in all three cell lines, showing that the requirement for TGF-beta signaling at invasion can be divorced from TGF-beta-induced growth arrest. TGF-beta pretreatment of mink lung cells expressing wild-type TbetaR1 caused a marked enhancement of infection, but no enhancement was seen in JD1, JM2, and JM3 cells, showing that the ability of TGF-beta to stimulate infection is associated with growth arrest. Likewise, expression of SMAD7 or SMAD2SA, inhibitors of TGF-beta signaling, did not block infection by T. cruzi but did block the enhancement of infection by TGF-beta. Taken together, these results show that there is a dual role for TGF-beta signaling in T. cruzi infection. The initial invasion of the host cell is independent of both TGF-beta-dependent gene expression and growth arrest, but TGF-beta stimulation of infection requires a fully functional TGF-beta signaling pathway.

Topics: Animals; Cell Division; Cell Line; Chagas Disease; Chlorides; DNA-Binding Proteins; Dose-Response Relationship, Drug; Epithelial Cells; Lung; Mink; Mutagenesis; Receptors, Transforming Growth Factor beta; Recombinant Proteins; Signal Transduction; Smad2 Protein; Smad7 Protein; Trans-Activators; Transforming Growth Factor beta; Zinc Compounds

The effects of transforming growth factor beta (TGF-beta) on interferon gamma-mediated killing of the intracellular protozoan parasite Trypanosoma cruzi and on the course of T. cruzi infection in mice were investigated. Spleen cells from mice with acute T. cruzi infections were found to produce elevated levels of biologically active TGF-beta in vitro, and the possibility that TGF-beta may mediate certain aspects of T. cruzi infection was then addressed. When mouse peritoneal macrophages were treated with TGF-beta in vitro, the ability of IFN-gamma to activate intracellular inhibition of the parasite was blocked. This occurred whether cells were treated with TGF-beta either before or after IFN-gamma treatment. TGF-beta treatment also blocked the T. cruzi-inhibiting effects of IGN-gamma on human macrophages. Additionally, treatment of human macrophages with TGF-beta alone led to increased parasite replication in these cells. The effects of TGF-beta on T. cruzi infection in vivo were then investigated. Susceptible C57BL/6 mice developed higher parasitemias and died earlier when treated with TGF-beta during the course of infection. Resistant C57BL/6 x DBA/2 F1 mice treated with TGF-beta also had increased parasitemias, and 50% mortality, compared with no mortality in infected, saline-treated controls. A single dose of TGF-beta, given at the time of infection, was sufficient to significantly decrease resistance to infection in F1 mice and to exacerbate infection in susceptible C57BL/6 mice. Furthermore, a single injection of TGF-beta was sufficient to counter the in vivo protective effects of IFN-gamma. We conclude that TGF-beta, produced during acute T. cruzi infection in mice, is a potent inhibitor of the effects of macrophage activating cytokines in vivo and in vitro and may play a role in regulating infection.

Topics: Animals; Cells, Cultured; Chagas Disease; Humans; In Vitro Techniques; Interferon-gamma; Macrophages; Mice; Mice, Inbred Strains; Spleen; Transforming Growth Factor beta; Trypanosoma cruzi