RESUMO
Pregnancy-associated malaria is often associated with adverse pregnancy outcomes. Placental circulatory impairments are an intriguing and unsolved component of malaria pathophysiology. Here, we uncovered a Toll-like receptor 4 (TLR4)-TRIF-endothelin axis that controls trophoblast motility and is linked to fetal protection during Plasmodium infection. In a cohort of 401 pregnancies from northern Brazil, we found that infection during pregnancy reduced expression of endothelin receptor B in syncytiotrophoblasts, while endothelin expression was only affected during acute infection. We further show that quantitative expression of placental endothelin and endothelin receptor B proteins are differentially controlled by maternal and fetal TLR4 alleles. Using murine malaria models, we identified placental autonomous responses to malaria infection mediated by fetally encoded TLR4 that not only controlled placental endothelin gene expression but also correlated with fetal viability protection. In vitro assays showed that control of endothelin expression in fetal syncytiotrophoblasts exposed to Plasmodium-infected erythrocytes was dependent on TLR4 via the TRIF pathway but not MyD88 signaling. Time-lapse microscopy in syncytiotrophoblast primary cultures and cell invasion assays demonstrated that ablation of TLR4 or endothelin receptor blockade abrogates trophoblast collective motility and cell migration responses to infected erythrocytes. These results cohesively substantiate the hypothesis that fetal innate immune sensing, namely, the TRL4-TRIF pathway, exerts a fetal protective role during malaria infection by mediating syncytiotrophoblast vasoregulatory responses that counteract placental insufficiency.
Assuntos
Endotelinas/metabolismo , Placenta/metabolismo , Placenta/parasitologia , Transdução de Sinais , Receptor 4 Toll-Like/metabolismo , Trofoblastos/metabolismo , Biomarcadores , Brasil , Feminino , Interações Hospedeiro-Patógeno/imunologia , Humanos , Malária/imunologia , Malária/metabolismo , Malária/parasitologia , Placenta/imunologia , Gravidez , Complicações Parasitárias na Gravidez , Resultado da GravidezRESUMO
Placental malaria (PM) is associated with severe inflammation leading to abortion, preterm delivery, and intrauterine growth restriction. Innate immunity responses play critical roles, but the mechanisms underlying placental immunopathology are still unclear. Here, we investigated the role of inflammasome activation in PM by scrutinizing human placenta samples from an endemic area and ablating inflammasome components in a PM mouse model. The reduction in birth weight in babies from infected mothers is paralleled by increased placental expression of AIM2 and NLRP3 inflammasomes. Using genetic dissection, we reveal that inflammasome activation pathways are involved in the production and detrimental action of interleukin-1ß (IL-1ß) in the infected placenta. The IL-1R pharmacological antagonist Anakinra improved pregnancy outcomes by restoring fetal growth and reducing resorption in an experimental model. These findings unveil that IL-1ß-mediated signaling is a determinant of PM pathogenesis, suggesting that IL-1R antagonists can improve clinical outcomes of malaria infection in pregnancy.
Assuntos
Inflamassomos/efeitos dos fármacos , Interleucina-1beta/imunologia , Malária Falciparum/imunologia , Malária/imunologia , Plasmodium falciparum/patogenicidade , Complicações Parasitárias na Gravidez/imunologia , Transdução de Sinais/efeitos dos fármacos , Animais , Caspase 1/genética , Caspase 1/imunologia , Linhagem Celular , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/imunologia , Feminino , Regulação da Expressão Gênica , Humanos , Imunidade Inata , Fatores Imunológicos/farmacologia , Inflamassomos/genética , Inflamassomos/imunologia , Interferon gama/genética , Interferon gama/imunologia , Proteína Antagonista do Receptor de Interleucina 1/farmacologia , Interleucina-1beta/antagonistas & inibidores , Interleucina-1beta/genética , Malária/tratamento farmacológico , Malária/genética , Malária/parasitologia , Malária Falciparum/genética , Malária Falciparum/parasitologia , Malária Falciparum/patologia , Camundongos , Camundongos Knockout , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/imunologia , Plasmodium berghei/imunologia , Plasmodium berghei/patogenicidade , Plasmodium falciparum/imunologia , Gravidez , Complicações Parasitárias na Gravidez/genética , Complicações Parasitárias na Gravidez/parasitologia , Complicações Parasitárias na Gravidez/prevenção & controle , Receptores de Interleucina-1/genética , Receptores de Interleucina-1/imunologia , Transdução de Sinais/imunologia , Células THP-1 , Trofoblastos/efeitos dos fármacos , Trofoblastos/imunologia , Trofoblastos/parasitologia , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologiaRESUMO
ABSTRACT Introduction: The Mycobacterium tuberculosis East African-Indian (EAI) spoligotyping family (belonging to lineage 1, Indo-Oceanic, defined by the region of deletion RD239) is distributed worldwide, but is more prevalent in Southeast Asia, India, and East Africa. Studies in Latin America have rarely identified EAI. In this study, we describe the occurrence of the EAI family in Brazil. Methods: EAI was identified in a systematic literature review of genetic diversity studies pertaining to M. tuberculosis in Brazil, as well as in a survey conducted in Salvador, Bahia, located in the northeastern region of this country. Results: The EAI6-BGD1 spoligotyping family and the EAI5 Spoligotype International Type (SIT) 1983 clade were the most frequently reported, with wide distribution of this particular clade described in Brazil. The distribution of other EAI spoligotyping patterns with broader worldwide distribution was restricted to the southeastern region of the country. Conclusions: EAI may be endemic at a low frequency in Brazil, with some clades indicating increased fitness with respect to this population.
Assuntos
DNA Bacteriano/genética , Técnicas de Tipagem Bacteriana , Mycobacterium tuberculosis/genética , Brasil , Filogeografia , Genótipo , Mycobacterium tuberculosis/classificaçãoRESUMO
INTRODUCTION: The Mycobacterium tuberculosis East African-Indian (EAI) spoligotyping family (belonging to lineage 1, Indo-Oceanic, defined by the region of deletion RD239) is distributed worldwide, but is more prevalent in Southeast Asia, India, and East Africa. Studies in Latin America have rarely identified EAI. In this study, we describe the occurrence of the EAI family in Brazil. METHODS: EAI was identified in a systematic literature review of genetic diversity studies pertaining to M. tuberculosis in Brazil, as well as in a survey conducted in Salvador, Bahia, located in the northeastern region of this country. RESULTS: The EAI6-BGD1 spoligotyping family and the EAI5 Spoligotype International Type (SIT) 1983 clade were the most frequently reported, with wide distribution of this particular clade described in Brazil. The distribution of other EAI spoligotyping patterns with broader worldwide distribution was restricted to the southeastern region of the country. CONCLUSIONS: EAI may be endemic at a low frequency in Brazil, with some clades indicating increased fitness with respect to this population.
Assuntos
Técnicas de Tipagem Bacteriana , DNA Bacteriano/genética , Mycobacterium tuberculosis/genética , Brasil , Genótipo , Mycobacterium tuberculosis/classificação , FilogeografiaRESUMO
Human tuberculosis is an infectious disease caused by bacteria from the Mycobacterium tuberculosis complex (MTBC). Although spoligotyping and MIRU-VNTR are standard methodologies in MTBC genetic epidemiology, recent studies suggest that Single Nucleotide Polymorphisms (SNP) are advantageous in phylogenetics and strain group/lineages identification. In this work we use a set of 79 SNPs to characterize 1987 MTBC isolates from Portugal and 141 from Northeast Brazil. All Brazilian samples were further characterized using spolygotyping. Phylogenetic analysis against a reference set revealed that about 95% of the isolates in both populations are singly attributed to bacterial lineage 4. Within this lineage, the most frequent strain groups in both Portugal and Brazil are LAM, followed by Haarlem and X. Contrary to these groups, strain group T showed a very different prevalence between Portugal (10%) and Brazil (1.5%). Spoligotype identification shows about 10% of mis-matches compared to the use of SNPs and a little more than 1% of strains unidentifiability. The mis-matches are observed in the most represented groups of our sample set (i.e., LAM and Haarlem) in almost the same proportion. Besides being more accurate in identifying strain groups/lineages, SNP-typing can also provide phylogenetic relationships between strain groups/lineages and, thus, indicate cases showing phylogenetic incongruence. Overall, the use of SNP-typing revealed striking similarities between MTBC populations from Portugal and Brazil.
Assuntos
Mycobacterium tuberculosis/genética , Tuberculose/epidemiologia , Tuberculose/microbiologia , Brasil/epidemiologia , Análise por Conglomerados , DNA Bacteriano/genética , DNA Intergênico/genética , Humanos , Epidemiologia Molecular , Tipagem Molecular , Mycobacterium tuberculosis/classificação , Filogenia , Polimorfismo de Nucleotídeo Único , Portugal/epidemiologiaRESUMO
Chagas' disease is a protozoosis caused by Trypanosoma cruzi that frequently shows severe chronic clinical complications of the heart or digestive system. Neurological disorders due to T. cruzi infection are also described in children and immunosuppressed hosts. We have previously reported that IL-12p40 knockout (KO) mice infected with the T. cruzi strain Sylvio X10/4 develop spinal cord neurodegenerative disease. Here, we further characterized neuropathology, parasite burden and inflammatory component associated to the fatal neurological disorder occurring in this mouse model. Forelimb paralysis in infected IL-12p40KO mice was associated with 60% (p<0.05) decrease in spinal cord neuronal density, glutamate accumulation (153%, p<0.05) and strong demyelization in lesion areas, mostly in those showing heavy protein nitrosylation, all denoting a neurotoxic degenerative profile. Quantification of T. cruzi 18S rRNA showed that parasite burden was controlled in the spinal cord of WT mice, decreasing from the fifth week after infection, but progressive parasite dissemination was observed in IL-12p40KO cords concurrent with significant accumulation of the astrocytic marker GFAP (317.0%, p<0.01) and 8-fold increase in macrophages/microglia (p<0.01), 36.3% (p<0.01) of which were infected. Similarly, mRNA levels for CD3, TNF-α, IFN-γ, iNOS, IL-10 and arginase I declined in WT spinal cords about the fourth or fifth week after infection, but kept increasing in IL-12p40KO mice. Interestingly, compared to WT tissue, lower mRNA levels for IFN-γ were observed in the IL-12p40KO spinal cords up to the fourth week of infection. Together the data suggest that impairments of parasite clearance mechanisms in IL-12p40KO mice elicit prolonged spinal cord inflammation that in turn leads to irreversible neurodegenerative lesions.
Assuntos
Doença de Chagas/genética , Doença de Chagas/parasitologia , Subunidade p40 da Interleucina-12/deficiência , Degeneração Neural/parasitologia , Medula Espinal/metabolismo , Medula Espinal/parasitologia , Trypanosoma cruzi , Animais , Morte Celular , Doença de Chagas/patologia , Modelos Animais de Doenças , Feminino , Gliose/patologia , Humanos , Subunidade p40 da Interleucina-12/genética , Macrófagos/patologia , Camundongos , Camundongos Knockout , Microglia/patologia , Atividade Motora , Mielite/genética , Mielite/parasitologia , Mielite/patologia , Medula Espinal/patologia , Trypanosoma cruzi/patogenicidadeRESUMO
Intravenous challenge with Trypanosoma cruzi can be used to investigate the process and consequences of blood parasite clearance in experimental Chagas disease. One hour after intravenous challenge of chronically infected mice with 5x10(6) trypomastigotes, the liver constituted a major site of parasite accumulation, as revealed by PCR. Intact parasites and/or parasite remnants were visualized at this time point scattered in the liver parenchyma. Moreover, at this time, many of liver-cleared parasites were viable, as estimated by the frequency of positive cultures, which considerably diminished after 48 h. Following clearance, the number of infiltrating cells in the hepatic tissue notably increased: initially (at 24 h) as diffuse infiltrates affecting the whole parenchyma, and at 48 h, in the form of large focal infiltrates in both the parenchyma and perivascular spaces. Phenotypic characterization of liver-infiltrating cells 24 h after challenge revealed an increase in Mac1(+), CD8(+) and CD4(+) cells, followed by natural killer (NK) cells. As evidence that liver-infiltrating CD4(+) and CD8(+) cells were activated, increased frequencies of CD69(+)CD8(+), CD69(+)CD4(+) and CD25(+)CD122(+)CD4(+) cells were observed at 24 and 48 h after challenge, and of CD25(-)CD122(+)CD4(+) cells at 48 h. The major role of CD4(+) cells in liver protection was suggested by data showing a very high frequency of interferon (IFN)-gamma-producing CD4(+) cells 24 h after challenge. In contrast, liver CD8(+) cells produced little IFN-gamma, even though they showed an enhanced potential for secreting this cytokine, as revealed by in vitro T cell receptor (TCR) stimulation. Confirming the effectiveness of the liver immune response in blood parasite control during the chronic phase of infection, no live parasites were detected in this organ 7 days after challenge.