RESUMO
Chagas disease is responsible for more than 10,000 deaths per year and about 6 to 7 million infected people worldwide. In its chronic stage, patients can develop mega-colon, mega-esophagus, and cardiomyopathy. Differences in clinical outcomes may be determined, in part, by the genetic background of the parasite that causes Chagas disease. Trypanosoma cruzi has a high genetic diversity, and each group of strains may elicit specific pathological responses in the host. Conflicting results have been reported in studies using various combinations of mammalian host-T. cruzi strains. We previously profiled the transcriptomic signatures resulting from infection of L6E9 rat myoblasts with four reference strains of T. cruzi (Brazil, CL, Y, and Tulahuen). The four strains induced similar overall gene expression alterations in the myoblasts, although only 21 genes were equally affected by all strains. Cardiotrophin-like cytokine factor 1 (Clcf1) was one of the genes found to be consistently upregulated by the infection with all four strains of T. cruzi. This cytokine is a member of the interleukin-6 family that binds to glycoprotein 130 receptor and activates the JAK/STAT signaling pathway, which may lead to muscle cell hypertrophy. Another commonly upregulated gene was tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein theta (Ywhaq, 14-3-3 protein Θ), present in the Cell Cycle Pathway. In the present work, we reanalyzed our previous microarray dataset, aiming at understanding in more details the transcriptomic impact that each strain has on JAK/STAT signaling and Cell Cycle pathways. Using Pearson correlation analysis between the expression levels of gene pairs in biological replicas from each pathway, we determined the coordination between such pairs in each experimental condition and the predicted protein interactions between the significantly altered genes by each strain. We found that although these highlighted genes were similarly affected by all four strains, the downstream genes or their interaction partners were not necessarily equally affected, thus reinforcing the idea of the role of parasite background on host cell transcriptome. These new analyses provide further evidence to the mechanistic understanding of how distinct T. cruzi strains lead to diverse remodeling of host cell transcriptome.
Assuntos
Trypanosoma cruzi , Animais , Brasil , Ciclo Celular , Humanos , Mioblastos , Ratos , Transdução de Sinais , Transcriptoma , Trypanosoma cruzi/genéticaRESUMO
PURPOSE OF REVIEW: Trypanosoma cruzi is the causative agent of Chagas disease. Decades after initial infection, ~30% of individuals can develop chronic chagasic cardiomyopathy. There are several proposed mechanisms for pathogenesis of Chagas disease, including parasite persistence, immune responses against parasite or self that continue in the heart, vascular compromise, and involvement of autonomous and central nervous system. Herein, we will focus on the significance of macrophages, mitochondrial dysfunction, and oxidative stress in progression of chagasic cardiomyopathy. RECENT FINDINGS: The current literature suggests that T. cruzi prevents cytotoxic activities of the innate immune cells and persists in the host, contributing to mitochondrial oxidative stress. We discuss how the neoantigens generated due to cellular oxidative damage contribute to chronic inflammatory stress in chagasic disease. SUMMARY: We propose that metabolic regulators, PARP-1/SIRT1, determine the disease outcome by modulating the mitochondrial and macrophage stress and antioxidant/oxidant imbalance, and offer a potential new therapy against chronic Chagas disease.
RESUMO
Dystrophin, an important protein of the dystrophin-glycoprotein complex, has been implicated in the pathogenesis of experimental Chagas disease. It is important for the maintenance of cell shape and contraction force transmission. Dystrophin loss has been related to end-stage cardiac myopathies and proposed as a common route for myocardial dysfunction and progression to advanced heart failure. Evidence suggests that calpains, calcium-dependent proteases, digest dystrophin when the calcium concentration is compatible with their activation. The objective of this in vitro study was to test the hypothesis that dantrolene, a calcium channel blocker, improves structural changes induced by serum from Trypanosoma cruzi-infected mice. Cultured neonatal cardiac myocytes were incubated with serum from T. cruzi-infected mice and treated with dantrolene for 24 h. Immunofluorescence and immunoblotting were performed to evaluate dystrophin and calpain-1 protein expression. The levels of dystrophin decreased 13 % and calpain increased 17 % after incubation of cultured neonatal cardiac myocytes with serum from T. cruzi-infected mice. The treatment with dantrolene restored the dystrophin and calpain levels near control levels. Our results demonstrate that alterations in calcium homeostasis in cardiac myocytes are responsible, in part, for cardiac structural changes in experimentally induced T. cruzi myocarditis and that calpain inhibitors may be beneficial in Chagasic heart disease.
Assuntos
Doença de Chagas/sangue , Dantroleno/farmacologia , Distrofina/química , Soro , Trypanosoma cruzi , Animais , Animais Recém-Nascidos , Células Cultivadas , Doença de Chagas/patologia , Imunofluorescência , Camundongos , Relaxantes Musculares Centrais/farmacologia , Miócitos CardíacosRESUMO
Cardiac dysfunction caused by the impairment of myocardial contractility has been recognized as an important factor contributing to the high mortality in sepsis. Calpain activation in the heart takes place in response to increased intracellular calcium influx resulting in proteolysis of structural and contractile proteins with subsequent myocardial dysfunction. The purpose of the present study was to test the hypothesis that increased levels of calpain in the septic heart leads to disruption of structural and contractile proteins and that administration of calpain inhibitor-1 (N-acetyl-leucinyl-leucinyl-norleucinal (ALLN)) after sepsis induced by cecal ligation and puncture prevents cardiac protein degradation. We also tested the hypothesis that calpain plays a role in the modulation of protein synthesis/degradation through the activation of proteasome-dependent proteolysis and inhibition of the mTOR pathway. Severe sepsis significantly increased heart calpain-1 levels and promoted ubiquitin and Pa28ß over-expression with a reduction in the mTOR levels. In addition, sepsis reduced the expression of structural proteins dystrophin and ß-dystroglycan as well as the contractile proteins actin and myosin. ALLN administration prevented sepsis-induced increases in calpain and ubiquitin levels in the heart, which resulted in decreased of structural and contractile proteins degradation and basal mTOR expression levels were re-established. Our results support the concept that increased calpain concentrations may be part of an important mechanism of sepsis-induced cardiac muscle proteolysis.
Assuntos
Calpaína/metabolismo , Distrofina/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Sepse/patologia , Serina-Treonina Quinases TOR/metabolismo , Ubiquitina/metabolismo , Actinas/metabolismo , Animais , Calpaína/antagonistas & inibidores , Calpaína/genética , Cardiomiopatias/complicações , Cardiomiopatias/patologia , Modelos Animais de Doenças , Expressão Gênica/efeitos dos fármacos , Leupeptinas/farmacologia , Leupeptinas/uso terapêutico , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia de Fluorescência , Miocárdio/metabolismo , Miocárdio/patologia , Miosinas/metabolismo , Proteólise/efeitos dos fármacos , Sepse/etiologia , Sepse/prevenção & controle , Serina-Treonina Quinases TOR/antagonistas & inibidoresRESUMO
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor involved in controlling several aspects of immune responses, including the activation and differentiation of specific T cell subsets and antigen-presenting cells, thought to be relevant in the context of experimental Trypanosoma cruzi infection. The relevance of AhR for the outcome of T. cruzi infection is not known and was investigated here. We infected wild-type (WT) mice and AhR knockout (AhR KO) mice with T. cruzi (Y strain) and determined levels of parasitemia, myocardial inflammation and fibrosis, expression of AhR/cytokines/suppressor of cytokine signaling (SOCS) (spleen/heart), and production of nitric oxide (NO), reactive oxygen species (ROS), and peroxynitrite (ONOO(-)) (spleen). AhR expression was increased in the heart of infected WT mice. Infected AhR KO mice displayed significantly reduced parasitemia, inflammation, and fibrosis of the myocardium. This was associated with an anticipated increased immune response characterized by increased levels of inflammatory cytokines and reduced expression of SOCS2 and SOCS3 in the heart. In vitro, AhR deficiency caused impairment in parasite replication and decreased levels of ROS production. In conclusion, AhR influences the development of murine Chagas disease by modulating ROS production and regulating the expression of key physiological regulators of inflammation, SOCS1 to -3, associated with the production of cytokines during experimental T. cruzi infection.
Assuntos
Doença de Chagas/fisiopatologia , Citocinas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Receptores de Hidrocarboneto Arílico/fisiologia , Trypanosoma cruzi/fisiologia , Animais , Cardiomiopatia Chagásica/metabolismo , Cardiomiopatia Chagásica/patologia , Doença de Chagas/metabolismo , Doença de Chagas/patologia , Modelos Animais de Doenças , Camundongos , Camundongos Knockout , Miocardite/metabolismo , Miocardite/patologia , Óxido Nítrico/metabolismo , Ácido Peroxinitroso/metabolismo , Receptores de Hidrocarboneto Arílico/metabolismo , Baço/metabolismo , Proteínas Supressoras da Sinalização de Citocina/metabolismoRESUMO
Plasmodium falciparum infection results in severe malaria in humans, affecting various organs, including the liver, spleen and brain, and resulting in high morbidity and mortality. The Plasmodium berghei ANKA (PbA) infection in mice closely recapitulates many aspects of human cerebral malaria (CM); thus, this model has been used to investigate the pathogenesis of CM. Suppressor of cytokine signaling 2 (SOCS2), an intracellular protein induced by cytokines and hormones, modulates the immune response, neural development, neurogenesis and neurotrophic pathways. However, the role of SOCS2 during CM remains unknown. SOCS2 knockout (SOCS2(-/-)) mice infected with PbA show an initial resistance to infection with reduced parasitemia and production of TNF, TGF-ß, IL-12 and IL-17 in the brain. Interestingly, in the late phase of infection, SOCS2(-/-) mice display increased parasitemia and reduced Treg cell infiltration, associated with enhanced levels of Th1 and Th17 cells and related cytokines IL-17, IL-6, and TGF-ß in the brain. A significant reduction in protective neurotrophic factors, such as glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF), was also observed. Moreover, the molecular alterations in the brain of infected SOCS2(-/-) mice were associated with anxiety-related behaviors and cognition impairment. Mechanistically, these results revealed enhanced nitric oxide (NO) production in PbA-infected SOCS2(-/-) mice, and the inhibition of NO synthesis through l-NAME led to a marked decrease in survival, the disruption of parasitemia control and more pronounced anxiety-like behavior. Treatment with l-NAME also shifted the levels of Th1, Th7 and Treg cells in the brains of infected SOCS2(-/-) mice to the background levels observed in infected WT, with remarkable exception of increased CD8(+)IFN(+) T cells and inflammatory monocytes. These results indicate that SOCS2 plays a dual role during PbA infection, being detrimental in the control of the parasite replication but crucial in the regulation of the immune response and production of neurotrophic factors. Here, we provided strong evidence of a critical relationship between SOCS2 and NO in the orchestration of the immune response and development of CM during PbA infection.
Assuntos
Malária Cerebral/imunologia , Proteínas Supressoras da Sinalização de Citocina/imunologia , Animais , Encéfalo/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Feminino , Malária Cerebral/metabolismo , Malária Cerebral/parasitologia , Malária Cerebral/terapia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fatores de Crescimento Neural/metabolismo , Plasmodium berghei/isolamento & purificação , Baço/metabolismo , Proteínas Supressoras da Sinalização de Citocina/antagonistas & inibidores , Proteínas Supressoras da Sinalização de Citocina/deficiência , Proteínas Supressoras da Sinalização de Citocina/metabolismo , Linfócitos T Reguladores/metabolismo , Células Th17/metabolismo , Fator de Crescimento Transformador beta/metabolismoRESUMO
A rich, collaborative program funded by the US NIH Fogarty program in 2004 has provided for a decade of remarkable opportunities for scientific advancement through the training of Brazilian undergraduate, graduate and postdoctoral students from the Federal University and Oswaldo Cruz Foundation systems at Albert Einstein College of Medicine. The focus of the program has been on the development of trainees in the broad field of Infectious Diseases, with a particular focus on diseases of importance to the Brazilian population. Talented trainees from various regions in Brazil came to Einstein to learn techniques and study fungal, parasitic and bacterial pathogens. In total, 43 trainees enthusiastically participated in the program. In addition to laboratory work, these students took a variety of courses at Einstein, presented their results at local, national and international meetings, and productively published their findings. This program has led to a remarkable synergy of scientific discovery for the participants during a time of rapid acceleration of the scientific growth in Brazil. This collaboration between Brazilian and US scientists has benefitted both countries and serves as a model for future training programs between these countries.
Assuntos
Educação/história , Educação/organização & administração , Cooperação Internacional/história , Pessoal de Laboratório/educação , Brasil , Educação/economia , História do Século XXI , Humanos , Pessoal de Laboratório/economia , National Institutes of Health (U.S.) , Estados Unidos , Recursos HumanosRESUMO
Abstract A rich, collaborative program funded by the US NIH Fogarty program in 2004 has provided for a decade of remarkable opportunities for scientific advancement through the training of Brazilian undergraduate, graduate and postdoctoral students from the Federal University and Oswaldo Cruz Foundation systems at Albert Einstein College of Medicine. The focus of the program has been on the development of trainees in the broad field of Infectious Diseases, with a particular focus on diseases of importance to the Brazilian population. Talented trainees from various regions in Brazil came to Einstein to learn techniques and study fungal, parasitic and bacterial pathogens. In total, 43 trainees enthusiastically participated in the program. In addition to laboratory work, these students took a variety of courses at Einstein, presented their results at local, national and international meetings, and productively published their findings. This program has led to a remarkable synergy of scientific discovery for the participants during a time of rapid acceleration of the scientific growth in Brazil. This collaboration between Brazilian and US scientists has benefitted both countries and serves as a model for future training programs between these countries.
Assuntos
Brasil/economia , Brasil/educação , Brasil/história , Brasil , Brasil/organização & administração , Educação/economia , Educação/educação , Educação/história , Educação , Educação/organização & administração , /economia , /educação , /história , /organização & administração , Humanos/economia , Humanos/educação , Humanos/história , Humanos , Humanos/organização & administração , Cooperação Internacional/economia , Cooperação Internacional/educação , Cooperação Internacional/história , Cooperação Internacional , Cooperação Internacional/organização & administração , Pessoal de Laboratório/economia , Pessoal de Laboratório/educação , Pessoal de Laboratório/história , Pessoal de Laboratório , Pessoal de Laboratório/organização & administração , National Institutes of Health (U.S.)/economia , National Institutes of Health (U.S.)/educação , National Institutes of Health (U.S.)/história , National Institutes of Health (U.S.) , National Institutes of Health (U.S.)/organização & administração , Estados Unidos/economia , Estados Unidos/educação , Estados Unidos/história , Estados Unidos , Estados Unidos/organização & administraçãoRESUMO
Abstract A rich, collaborative program funded by the US NIH Fogarty program in 2004 has provided for a decade of remarkable opportunities for scientific advancement through the training of Brazilian undergraduate, graduate and postdoctoral students from the Federal University and Oswaldo Cruz Foundation systems at Albert Einstein College of Medicine. The focus of the program has been on the development of trainees in the broad field of Infectious Diseases, with a particular focus on diseases of importance to the Brazilian population. Talented trainees from various regions in Brazil came to Einstein to learn techniques and study fungal, parasitic and bacterial pathogens. In total, 43 trainees enthusiastically participated in the program. In addition to laboratory work, these students took a variety of courses at Einstein, presented their results at local, national and international meetings, and productively published their findings. This program has led to a remarkable synergy of scientific discovery for the participants during a time of rapid acceleration of the scientific growth in Brazil. This collaboration between Brazilian and US scientists has benefitted both countries and serves as a model for future training programs between these countries.(AU)
Assuntos
Brasil/economia , Brasil/educaçãoRESUMO
BACKGROUND: Cerebral malaria (CM) is debilitating and sometimes fatal. Disease severity has been associated with poor treatment access, therapeutic complexity and drug resistance and, thus, alternative therapies are increasingly necessary. In this study, the effect of the administration of Agaricus blazei, a mushroom of Brazilian origin in a model of CM caused by Plasmodium berghei, strain ANKA, was investigated in mice. METHODS: C57BL/6 mice were pre-treated with aqueous extract or fractions of A. blazei, or chloroquine, infected with P. berghei ANKA and then followed by daily administration of A. blazei or chloroquine. Parasitaemia, body weight, survival and clinical signs of the disease were evaluated periodically. The concentration of pro-and anti-inflammatory cytokines, histopathology and in vitro analyses were performed. RESULTS: Mice treated with A. blazei aqueous extract or fraction C, that shows antioxidant activity, displayed lower parasitaemia, increased survival, reduced weight loss and protection against the development of CM. The administration of A. blazei resulted in reduced levels of TNF, IL-1ß and IL-6 production when compared to untreated P. berghei-infected mice. Agaricus blazei (aqueous extract or fraction C) treated infected mice displayed reduction of brain lesions. Although chloroquine treatment reduced parasitaemia, there was increased production of proinflammatory cytokines and damage in the CNS not observed with A. blazei treatment. Moreover, the in vitro pretreatment of infected erythrocytes followed by in vivo infection resulted in lower parasitaemia, increased survival, and little evidence of clinical signs of disease. CONCLUSIONS: This study strongly suggests that the administration of A. blazei (aqueous extract or fraction C) was effective in improving the consequences of CM in mice and may provide novel therapeutic strategies.
Assuntos
Agaricus/química , Anti-Inflamatórios/farmacologia , Antimaláricos/farmacologia , Produtos Biológicos/farmacologia , Malária Cerebral/tratamento farmacológico , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/uso terapêutico , Antimaláricos/química , Antimaláricos/uso terapêutico , Produtos Biológicos/química , Produtos Biológicos/uso terapêutico , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Citocinas/sangue , Feminino , Malária Cerebral/fisiopatologia , Malária Cerebral/prevenção & controle , Camundongos , Camundongos Endogâmicos C57BLRESUMO
BACKGROUND: Trypanosoma cruzi, the causative agent of Chagas disease, has high affinity for lipoproteins and adipose tissue. Infection results in myocarditis, fat loss and alterations in lipid homeostasis. This study was aimed at analyzing the effect of high fat diet (HFD) on regulating acute T. cruzi infection-induced myocarditis and to evaluate the effect of HFD on lipid metabolism in adipose tissue and heart during acute T. cruzi infection. METHODOLOGY/PRINCIPAL FINDINGS: CD1 mice were infected with T. cruzi (Brazil strain) and fed either a regular control diet (RD) or HFD for 35 days following infection. Serum lipid profile, tissue cholesterol levels, blood parasitemia, and tissue parasite load were analyzed to evaluate the effect of diet on infection. MicroPET and MRI analysis were performed to examine the morphological and functional status of the heart during acute infection. qPCR and immunoblot analysis were carried out to analyze the effect of diet on the genes involved in the host lipid metabolism during infection. Oil red O staining of the adipose tissue demonstrated reduced lipolysis in HFD compared to RD fed mice. HFD reduced mortality, parasitemia and cardiac parasite load, but increased parasite load in adipocytes. HFD decreased lipolysis during acute infection. Both qPCR and protein analysis demonstrated alterations in lipid metabolic pathways in adipose tissue and heart in RD fed mice, which were further modulated by HFD. Both microPET and MRI analyses demonstrated changes in infected RD murine hearts which were ameliorated by HFD. CONCLUSION/SIGNIFICANCE: These studies indicate that Chagasic cardiomyopathy is associated with a cardiac lipidpathy and that both cardiac lipotoxicity and adipose tissue play a role in the pathogenesis of Chagas disease. HFD protected mice from T. cruzi infection-induced myocardial damage most likely due to the effects of HFD on both adipogenesis and T. cruzi infection-induced cardiac lipidopathy.
Assuntos
Cardiomiopatia Chagásica/metabolismo , Miocardite/metabolismo , Adipogenia , Tecido Adiposo Branco/metabolismo , Animais , Brasil , Cardiomiopatia Chagásica/parasitologia , Cardiomiopatia Chagásica/patologia , LDL-Colesterol/sangue , Dieta Hiperlipídica , Metabolismo dos Lipídeos , Masculino , Camundongos , Camundongos Endogâmicos C3H , Miocardite/parasitologia , Miocardite/patologia , Miocárdio/metabolismo , Miocárdio/patologiaRESUMO
Chagasic cardiomyopathy, resulting from infection with the parasite Trypanosoma cruzi, was discovered more than a century ago and remains an incurable disease. Due to the unique properties of mesenchymal stem cells (MSC) we hypothesized that these cells could have therapeutic potential for chagasic cardiomyopathy. Recently, our group pioneered use of nanoparticle-labeled MSC to correlate migration with its effect in an acute Chagas disease model. We expanded our investigation into a chronic model and performed more comprehensive assays. Infected mice were treated with nanoparticle-labeled MSC and their migration was correlated with alterations in heart morphology, metalloproteinase activity, and expression of several proteins. The vast majority of labeled MSC migrated to liver, lungs and spleen whereas a small number of cells migrated to chagasic hearts. Magnetic resonance imaging demonstrated that MSC therapy reduced heart dilatation. Additionally metalloproteinase activity was higher in heart and other organs of infected mice. Protein expression analyses revealed that connexin 43, laminin γ1, IL-10 and INF-γ were affected by the disease and recovered after cell therapy. Interestingly, MSC therapy led to upregulation of SDF-1 and c-kit in the hearts. The beneficial effect of MSC therapy in Chagas disease is likely due to an indirect action of the cells of the heart, rather than the incorporation of large numbers of stem cells into working myocardium.
Assuntos
Transplante de Medula Óssea/métodos , Doença de Chagas/patologia , Doença de Chagas/terapia , Transplante de Células-Tronco Mesenquimais/métodos , Animais , Quimiocina CXCL12/análise , Citocinas/sangue , Modelos Animais de Doenças , Coração/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Camundongos , Imagem Molecular , Miocárdio/patologia , Proteínas Proto-Oncogênicas c-kit/análise , Radiografia , Resultado do TratamentoRESUMO
Previous studies have demonstrated loss/reduction of dystrophin in cardiomyocytes in both acute and chronic stages of experimental Trypanosoma cruzi (T. cruzi) infection in mice. The mechanisms responsible for dystrophin disruption in the hearts of mice acutely infected with T. cruzi are not completely understood. The present in vivo and in vitro studies were undertaken to evaluate the role of inflammation in dystrophin disruption and its correlation with the high mortality rate during acute infection. C57BL/6 mice were infected with T. cruzi and killed 14, 20 and 26 days post infection (dpi). The intensity of inflammation, cardiac expression of dystrophin, calpain-1, NF-κB, TNF-α, and sarcolemmal permeability were evaluated. Cultured neonatal murine cardiomyocytes were incubated with serum, collected at the peak of cytokine production and free of parasites, from T. cruzi-infected mice and dystrophin, calpain-1, and NF-κB expression analyzed. Dystrophin disruption occurs at the peak of mortality and inflammation and is associated with increased expression of calpain-1, TNF-α, NF-κB, and increased sarcolemmal permeability in the heart of T. cruzi-infected mice at 20 dpi confirmed by in vitro studies. The peak of mortality occurred only when significant loss of dystrophin in the hearts of infected animals occurred, highlighting the correlation between inflammation, dystrophin loss and mortality.
Assuntos
Doença de Chagas/metabolismo , Distrofina/fisiologia , Doença Aguda , Animais , Calpaína/metabolismo , Distrofina/metabolismo , Inflamação/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Miócitos Cardíacos/imunologia , Miócitos Cardíacos/parasitologia , NF-kappa B/metabolismo , Trypanosoma cruzi , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Sepsis, a major cause of morbidity/mortality in intensive care units worldwide, is commonly associated with cardiac dysfunction, which worsens the prognosis dramatically for patients. Although in recent years the concept of septic cardiomyopathy has evolved, the importance of myocardial structural alterations in sepsis has not been fully explored. This study offers novel and mechanistic data to clarify subcellular events that occur in the pathogenesis of septic cardiomyopathy and myocardial dysfunction in severe sepsis. Cultured neonatal mice cardiomyocytes subjected to serum obtained from mice with severe sepsis presented striking increment of [Ca(2+)]i and calpain-1 levels associated with decreased expression of dystrophin and disruption and derangement of F-actin filaments and cytoplasmic bleb formation. Severe sepsis induced in mice led to an increased expression of calpain-1 in cardiomyocytes. Moreover, decreased myocardial amounts of dystrophin, sarcomeric actin, and myosin heavy chain were observed in septic hearts associated with depressed cardiac contractile dysfunction and a very low survival rate. Actin and myosin from the sarcomere are first disassembled by calpain and then ubiquitinated and degraded by proteasome or sequestered inside specialized vacuoles called autophagosomes, delivered to the lysosome for degradation forming autophagolysosomes. Verapamil and dantrolene prevented the increase of calpain-1 levels and preserved dystrophin, actin, and myosin loss/reduction as well cardiac contractile dysfunction associated with strikingly improved survival rate. These abnormal parameters emerge as therapeutic targets, which modulation may provide beneficial effects on future vascular outcomes and mortality in sepsis. Further studies are needed to shed light on this mechanism, mainly regarding specific calpain inhibitors.
Assuntos
Cálcio/metabolismo , Homeostase , Miocárdio/metabolismo , Miocárdio/ultraestrutura , Miócitos Cardíacos/metabolismo , Sepse/patologia , Sepse/fisiopatologia , Actinas/metabolismo , Animais , Animais Recém-Nascidos , Western Blotting , Calpaína/metabolismo , Ceco/efeitos dos fármacos , Ceco/patologia , Células Cultivadas , Dantroleno/farmacologia , Distrofina/metabolismo , Imunofluorescência , Hemodinâmica/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Espaço Intracelular/metabolismo , Ligadura , Camundongos , Camundongos Endogâmicos C57BL , Miocárdio/patologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/patologia , Cadeias Pesadas de Miosina/metabolismo , Punções , Sarcômeros/efeitos dos fármacos , Sarcômeros/metabolismo , Volume Sistólico/efeitos dos fármacos , Análise de Sobrevida , Verapamil/farmacologiaRESUMO
BACKGROUND: Chagas disease, resulting from infection with the parasite Trypanosoma cruzi (T. cruzi), is a major cause of cardiomyopathy in Latin America. Drug therapy for acute and chronic disease is limited. Stem cell therapy with bone marrow mesenchymal cells (MSCs) has emerged as a novel therapeutic option for cell death-related heart diseases, but efficacy of MSC has not been tested in Chagas disease. METHODS AND RESULTS: We now report the use of cell-tracking strategies with nanoparticle labeled MSC to investigate migration of transplanted MSC in a murine model of Chagas disease, and correlate MSC biodistribution with glucose metabolism and morphology of heart in chagasic mice by small animal positron emission tomography (microPET). Mice were infected intraperitoneally with trypomastigotes of the Brazil strain of T. cruzi and treated by tail vein injection with MSC one month after infection. MSCs were labeled with near infrared fluorescent nanoparticles and tracked by an in vivo imaging system (IVIS). Our IVIS results two days after transplant revealed that a small, but significant, number of cells migrated to chagasic hearts when compared with control animals, whereas the vast majority of labeled MSC migrated to liver, lungs and spleen. Additionally, the microPET technique demonstrated that therapy with MSC reduced right ventricular dilation, a phenotype of the chagasic mouse model. CONCLUSIONS: We conclude that the beneficial effects of MSC therapy in chagasic mice arise from an indirect action of the cells in the heart rather than a direct action due to incorporation of large numbers of transplanted MSC into working myocardium.
Assuntos
Transplante de Medula Óssea/métodos , Cardiomiopatia Chagásica/terapia , Animais , Disponibilidade Biológica , Células da Medula Óssea/citologia , Cardiomiopatia Chagásica/patologia , Modelos Animais de Doenças , Fígado/patologia , Pulmão/patologia , Masculino , Camundongos , Miocárdio/patologia , Baço/patologia , Coloração e RotulagemRESUMO
Chagas disease caused by Trypanosoma cruzi remains an important neglected tropical disease and a cause of significant morbidity and mortality. No longer confined to endemic areas of Latin America, it is now found in non-endemic areas due to immigration. The parasite may persist in any tissue, but in recent years, there has been increased recognition of adipose tissue both as an early target of infection and a reservoir of chronic infection. The major complications of this disease are cardiomyopathy and megasyndromes involving the gastrointestinal tract. The pathogenesis of Chagas disease is complex and multifactorial involving many interactive pathways. The significance of innate immunity, including the contributions of cytokines, chemokines, reactive oxygen species, and oxidative stress, has been emphasized. The role of the components of the eicosanoid pathway such as thromboxane A(2) and the lipoxins has been demonstrated to have profound effects as both pro- and anti-inflammatory factors. Additionally, we discuss the vasoconstrictive actions of thromboxane A(2) and endothelin-1 in Chagas disease. Human immunity to T. cruzi infection and its role in pathogen control and disease progression have not been fully investigated. However, recently, it was demonstrated that a reduction in the anti-inflammatory cytokine IL-10 was associated with clinically significant chronic chagasic cardiomyopathy.
Assuntos
Doença de Chagas/imunologia , Trypanosoma cruzi/imunologia , Imunidade Adaptativa , Animais , Doença de Chagas/epidemiologia , Doença de Chagas/patologia , Humanos , Imunidade Inata , Estágios do Ciclo de Vida , Trypanosoma cruzi/crescimento & desenvolvimentoRESUMO
Infection with Trypanosoma cruzi induces inflammation, which limits parasite proliferation but may result in chagasic heart disease. Suppressor of cytokine signaling 2 (SOCS2) is a regulator of immune responses and may therefore participate in the pathogenesis of T. cruzi infection. SOCS2 is expressed during T. cruzi infection, and its expression is partially reduced in infected 5-lipoxygenase-deficient [knockout (KO)] mice. In SOCS2 KO mice, there was a reduction in both parasitemia and the expression of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), IL-6, IL-10, SOCS1, and SOCS3 in the spleen. Expression of IFN-γ, TNF-α, SOCS1, and SOCS3 was also reduced in the hearts of infected SOCS2 KO mice. There was an increase in the generation and expansion of T regulatory (Treg) cells and a decrease in the number of memory cells in T. cruzi-infected SOCS2 KO mice. Levels of lipoxinA(4) (LXA(4)) increased in these mice. Echocardiography studies demonstrated an impairment of cardiac function in T. cruzi-infected SOCS2 KO mice. There were also changes in calcium handling and in action potential waveforms, and reduced outward potassium currents in isolated cardiac myocytes. Our data suggest that reductions of inflammation and parasitemia in infected SOCS2-deficient mice may be secondary to the increases in Treg cells and LXA(4) levels. This occurs at the cost of greater infection-associated heart dysfunction, highlighting the relevance of balanced inflammatory and immune responses in preventing severe T. cruzi-induced disease.
Assuntos
Cardiomiopatia Chagásica/imunologia , Proteínas Supressoras da Sinalização de Citocina/imunologia , Doença Aguda , Animais , Araquidonato 5-Lipoxigenase/fisiologia , Células Cultivadas , Cardiomiopatia Chagásica/parasitologia , Cardiomiopatia Chagásica/patologia , Cardiomiopatia Chagásica/fisiopatologia , Citocinas/biossíntese , Modelos Animais de Doenças , Coração/parasitologia , Lipoxinas/metabolismo , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Miócitos Cardíacos/imunologia , Carga Parasitária , Parasitemia/imunologia , Técnicas de Patch-Clamp , Proteínas Supressoras da Sinalização de Citocina/deficiência , Subpopulações de Linfócitos T/imunologia , Trypanosoma cruzi/isolamento & purificaçãoRESUMO
The role of caveolin and caveolae in the pathogenesis of infection has only recently been appreciated. In this chapter, we have highlighted some important new data on the role of caveolin in infections due to bacteria, viruses and fungi but with particular emphasis on the protozoan parasites Leishmania spp., Trypanosoma cruzi and Toxoplasma gondii. This is a continuing area of research and the final chapter has not been written on this topic.
Assuntos
Caveolinas/metabolismo , Interações Hospedeiro-Patógeno , Infecções/metabolismo , Animais , Humanos , Infecções/microbiologia , Infecções/parasitologia , Infecções/virologiaRESUMO
Chagas disease, caused by the parasite Trypanosoma cruzi, is an important cause of cardiac disease in endemic areas of Latin America. It is now being diagnosed in nonendemic areas because of immigration. Typical cardiac manifestations of Chagas disease include dilated cardiomyopathy, congestive heart failure, arrhythmias, cardioembolism, and stroke. Clinical and laboratory-based research to define the pathology resulting from T. cruzi infection has shed light on many of the cellular and molecular mechanisms leading to these manifestations. Antiparasitic treatment may not be appropriate for patients with advanced cardiac disease. Clinical management of Chagas heart disease is similar to that used for cardiomyopathies caused by other processes. Cardiac transplantation has been successfully performed in a small number of patients with Chagas heart disease.