Human B cells infected by Trypanosoma cruzi undergo F-actin disruption and cell death via caspase-7 activation and cleavage of phospholipase Cgama1

B cells contribute to the immune system in many ways such as antigen presentation to CD4+ T cells, secretion of cytokines and lymphoid tissue organogenesis. Furthermore, they are the only cell type capable of producing immunoglobulins. B cells also account for critical aspects of the resistance against intracellular pathogens. Trypanosoma cruzi is an intracellular parasite that sabotages humoral response by depletion of immature B cells. Polyclonal activation and secretion of non-specific antibodies are also other mechanisms used by T cruzi to evade and subvert the mammalian host immune system, leading to increased parasitemia and susceptibility to Chagas’ disease. It remained unclear whether B cell depletion occurs due to direct contact with T. cruzi or results from a global increase in inflammation. Unlike previous reports, we demonstrated in this study that T. cruzi infects human B cells, resulting in parasite-induced activation of caspase-7 followed by proteolytic cleavage of phospholipase Cgama1 and cell death. These data contribute to explain the mechanisms ruling B-cell depletion and evasion of the immune response by T. cruzi.

Human B cells infected by Trypanosoma cruzi undergo F-actin disruption and cell death via caspase-7 activation and cleavage of phospholipase Cgama1

B cells contribute to the immune system in many ways such as antigen presentation to CD4+ T cells, secretion of cytokines and lymphoid tissue organogenesis. Furthermore, they are the only cell type capable of producing immunoglobulins. B cells also account for critical aspects of the resistance against intracellular pathogens. Trypanosoma cruzi is an intracellular parasite that sabotages humoral response by depletion of immature B cells. Polyclonal activation and secretion of non-specific antibodies are also other mechanisms used by T cruzi to evade and subvert the mammalian host immune system, leading to increased parasitemia and susceptibility to Chagas’ disease. It remained unclear whether B cell depletion occurs due to direct contact with T. cruzi or results from a global increase in inflammation. Unlike previous reports, we demonstrated in this study that T. cruzi infects human B cells, resulting in parasite-induced activation of caspase-7 followed by proteolytic cleavage of phospholipase Cgama1 and cell death. These data contribute to explain the mechanisms ruling B-cell depletion and evasion of the immune response by T. cruzi.

Pentachloropseudilin impairs angiogenesis by disrupting the actin cytoskeleton, integrin trafficking and the cell cycle

Class 1 myosins (Myo1s) were the first unconventional myosins identified and humans have eight known Myo1 isoforms. The Myo1 family is involved in the regulation of gene expression, cytoskeletal rearrangements, delivery of proteins to the cell surface, cell migration and spreading. Thus, the important role of Myo1s in different biological processes is evident. In this study, we have investigated the effects of pentachloropseudilin (PClP), a reversible and allosteric potent inhibitor of Myo1s, on angiogenesis. We demonstrated that treatment of cells with PClP promoted a decrease in the number of vessels. The observed inhibition of angiogenesis is likely to be related to the inhibition of cell proliferation, migration and adhesion, as well as to alteration of the actin cytoskeleton pattern, as shown on a PClP‐treated HUVEC cell line. Moreover, we also demonstrated that PClP treatment partially prevented the delivery of integrins to the plasma membrane. Finally, we showed that PClP caused DNA strand breaks, which are probably repaired during the cell cycle arrest in the G1 phase. Taken together, our results suggest that Myo1s participate directly in the angiogenesis process.

Increased ROS generation causes apoptosis-like death: mechanistic insights into the anti-Leishmania activity of a potent ruthenium(II) complex

Some metallodrugs that exhibit interesting biological activity contain transition metals such as ruthenium, and have been extensively exploited because of their antiparasitic potential. In previous study, we reported the remarkable anti-Leishmania activity of precursor cis-[RuIICl2(dppm)2], where dppm=bis(diphenylphosphino)methane, and new ruthenium(II) complexes, cis-[RuII(n2-O2CC10H13)(dppm)2]PF6 (bbato), cis-[RuII(n2-O2CC7H7S)(dppm)2]PF6 (mtbato) and cis-[RuII(n2-O2CC7H7O2)(dppm)2]PF6 (hmxbato) against some Leishmania species. In view of the promising activity of the hmxbato complex against Leishmania (Leishmania) amazonensis promastigotes, the present work investigated the possible parasite death mechanism involved in the action of this hmxbato and its precursor. We report, for the first time, that hmxbato and precursor promoted an increase in reactive oxygen species production, depolarization of the mitochondrial membrane, DNA fragmentation, formation of a pre-apoptotic peak, alterations in parasite morphology and formation of autophagic vacuoles. Taken together, our results suggest that these ruthenium complexes cause parasite death by apoptosis. Thus, this work provides relevant knowledge on the activity of ruthenium(II) complexes against L. (L.) amazonensis. Such information will be essential for the exploitation of these complexes as future candidates for cutaneous leishmaniasis treatment.

Action of copper(II) complex with ß-diketone and 1,10-phenanthroline (CBP-01) on sarcoma cells and biological effects under cell death

This work reports the biological evaluation of a copper complex of the type [Cu(O–O)(N–N)ClO4], in whichO–O = 4,4,4-trifluoro-1-phenyl-1,3-butanedione (Hbta) and N–N = 1,10-phenanthroline (phen), whose genericname is CBP-01. The cytotoxic effect of CBP-01 was evaluated by resazurin assay and cell proliferation wasdetermined by MTT assay. DNA fragmentation was analyzed by gel electrophoresis. Cell cycle progression wasdetected through propidium iodide (PI) staining. Apoptosis and autophagy were determined by, respectively,Annexin V and 7-AAD staining and monodansylcadaverine (MDC) staining. The changes in intracellular reactiveoxygen species levels were detected by DCFDA analysis. The copper complex CBP-01 showed in vitro antitumoractivity with IC50s values of 7.4µM against Sarcoma 180 and 26.4 against murine myoblast cells, displayingselectivity toward the tumor cell tested in vitro (SI > 3). An increase in reactive oxygen species (ROS) gen-eration was observed, which may be related to the action mechanism of the complex. The complex CBP-01 mayinduce DNA damage leading cells to accumulate at G0/G1 checkpoint where, apparently, cells that are not ableto recover from the damage are driven to cell death. Evidence has shown that cell death is initiated by autophagydysfunction, culminating in apoptosis induction. The search for new metal-based drugs is focused on overcomingthe drawbacks of already used agents such as acquired resistance and non-specificity; thus, the results obtainedwith CBP-01 show promising effects on cancer cells.

Increased ROS generation causes apoptosis-like death: mechanistic insights into the anti-Leishmania activity of a potent ruthenium(II) complex

Some metallodrugs that exhibit interesting biological activity contain transition metals such as ruthenium, and have been extensively exploited because of their antiparasitic potential. In previous study, we reported the remarkable anti-Leishmania activity of precursor cis-[RuIICl2(dppm)2], where dppm=bis(diphenylphosphino)methane, and new ruthenium(II) complexes, cis-[RuII(n2-O2CC10H13)(dppm)2]PF6 (bbato), cis-[RuII(n2-O2CC7H7S)(dppm)2]PF6 (mtbato) and cis-[RuII(n2-O2CC7H7O2)(dppm)2]PF6 (hmxbato) against some Leishmania species. In view of the promising activity of the hmxbato complex against Leishmania (Leishmania) amazonensis promastigotes, the present work investigated the possible parasite death mechanism involved in the action of this hmxbato and its precursor. We report, for the first time, that hmxbato and precursor promoted an increase in reactive oxygen species production, depolarization of the mitochondrial membrane, DNA fragmentation, formation of a pre-apoptotic peak, alterations in parasite morphology and formation of autophagic vacuoles. Taken together, our results suggest that these ruthenium complexes cause parasite death by apoptosis. Thus, this work provides relevant knowledge on the activity of ruthenium(II) complexes against L. (L.) amazonensis. Such information will be essential for the exploitation of these complexes as future candidates for cutaneous leishmaniasis treatment.

Action of copper(II) complex with ß-diketone and 1,10-phenanthroline (CBP-01) on sarcoma cells and biological effects under cell death

This work reports the biological evaluation of a copper complex of the type [Cu(O–O)(N–N)ClO4], in whichO–O = 4,4,4-trifluoro-1-phenyl-1,3-butanedione (Hbta) and N–N = 1,10-phenanthroline (phen), whose genericname is CBP-01. The cytotoxic effect of CBP-01 was evaluated by resazurin assay and cell proliferation wasdetermined by MTT assay. DNA fragmentation was analyzed by gel electrophoresis. Cell cycle progression wasdetected through propidium iodide (PI) staining. Apoptosis and autophagy were determined by, respectively,Annexin V and 7-AAD staining and monodansylcadaverine (MDC) staining. The changes in intracellular reactiveoxygen species levels were detected by DCFDA analysis. The copper complex CBP-01 showed in vitro antitumoractivity with IC50s values of 7.4µM against Sarcoma 180 and 26.4 against murine myoblast cells, displayingselectivity toward the tumor cell tested in vitro (SI > 3). An increase in reactive oxygen species (ROS) gen-eration was observed, which may be related to the action mechanism of the complex. The complex CBP-01 mayinduce DNA damage leading cells to accumulate at G0/G1 checkpoint where, apparently, cells that are not ableto recover from the damage are driven to cell death. Evidence has shown that cell death is initiated by autophagydysfunction, culminating in apoptosis induction. The search for new metal-based drugs is focused on overcomingthe drawbacks of already used agents such as acquired resistance and non-specificity; thus, the results obtainedwith CBP-01 show promising effects on cancer cells.

Chemical Composition and Bioactivity of Essential Oil from Blepharocalyx salicifolius.

Natural products represent a source of biologically active molecules that have an important role in drug discovery. The aromatic plant Blepharocalyx salicifolius has a diverse chemical constitution but the biological activities of its essential oils have not been thoroughly investigated. The aims of this paper were to evaluate in vitro cytotoxic, antifungal and antibacterial activities of an essential oil from leaves of B. salicifolius and to identify its main chemical constituents. The essential oil was extracted by steam distillation, chemical composition was determined by gas chromatography/mass spectrometry, and biological activities were performed by a microdilution broth method. The yield of essential oil was 0.86% (w/w), and the main constituents identified were bicyclogermacrene (17.50%), globulol (14.13%), viridiflorol (8.83%), γ-eudesmol (7.89%) and α-eudesmol (6.88%). The essential oil was cytotoxic against the MDA-MB-231 (46.60 µg·mL-1) breast cancer cell line, being more selective for this cell type compared to the normal breast cell line MCF-10A (314.44 µg·mL-1). Flow cytometry and cytotoxicity results showed that this oil does not act by inducing cell death, but rather by impairment of cellular metabolism specifically of the cancer cells. Furthermore, it presented antifungal activity against Paracoccidioides brasiliensis (156.25 µg·mL-1) but was inactive against other fungi and bacteria. Essential oil from B. salicifolius showed promising biological activities and is therefore a source of molecules to be exploited in medicine or by the pharmaceutical industry.

Trypanosoma cruzi modulates gene expression of plasma membrane repair-related proteins.

Plasma membrane injury and repair is particularly prevalent in muscle cells. Here, we aimed to verify dysferlin, acid sphingomyelinase and transcriptional factor EB gene expression during Trypanosoma cruzi infection in vitro and in vivo. Our results showed that the parasite modulates gene expression of these proteins in a way dependent on the number of plasma membrane interacting parasites and in a rapamycin-sensitive manner.

Mechanistic insights into the anti-angiogenic activity of Trypanosoma cruzi protein 21 and its potential impact on the onset of chagasic cardiomyopathy

Chronic chagasic cardiomyopathy (CCC) is arguably the most important form of the Chagas Disease, caused by the intracellular protozoan Trypanosoma cruzi; it is estimated that 10-30% of chronic patients develop this clinical manifestation. The most common and severe form of CCC can be related to ventricular abnormalities, such as heart failure, arrhythmias, heart blocks, thromboembolic events and sudden death. Therefore, in this study, we proposed to evaluate the anti-angiogenic activity of a recombinant protein from T. cruzi named P21 (rP21) and the potential impact of the native protein on CCC. Our data suggest that the anti-angiogenic activity of rP21 depends on the protein's direct interaction with the CXCR4 receptor. This capacity is likely related to the modulation of the expression of actin and angiogenesis-associated genes. Thus, our results indicate that T. cruzi P21 is an attractive target for the development of innovative therapeutic agents against CCC.

Intestinal parasites and commensals among individuals from a landless camping in the rural area of Uberlândia, Minas Gerais, Brazil.

We evaluated the occurrence of intestinal parasites and commensals among children and adults from a landless camping in the rural area of Uberlândia, State of Minas Gerais, Brazil, from October to November 2001. Stool samples from 78 individuals were examined by both the Baermann-Moraes and Lutz methods. Fifty-one (65.4%; CI 54.8 - 76.0) individuals were found to be infected, 23 (45.1%) children and 28 (54.9%) adults, of whom 34 (66.7%) were mono-infected, 9 (17.6%) bi-infected, and 8 (15.7%) poly-infected. In conclusion, the high prevalence of intestinal parasites and commensals suggests that parasitological exams should be periodically carried out in addition to the sanitation education and health special care in this population.

Intestinal parasites and commensals among individuals from a landless camping in the rural area of Uberlândia, Minas Gerais, Brazil

We evaluated the occurrence of intestinal parasites and commensals among children and adults from a landless camping in the rural area of Uberlândia, State of Minas Gerais, Brazil, from October to November 2001. Stool samples from 78 individuals were examined by both the Baermann-Moraes and Lutz methods. Fifty-one (65.4 percent; CI 54.8 - 76.0) individuals were found to be infected, 23 (45.1 percent) children and 28 (54.9 percent) adults, of whom 34 (66.7 percent) were mono-infected, 9 (17.6 percent) bi-infected, and 8 (15.7 percent) poly-infected. In conclusion, the high prevalence of intestinal parasites and commensals suggests that parasitological exams should be periodically carried out in addition to the sanitation education and health special care in this population

Aspectos eletroencefalográficos na disfunçäo cerebral mínima / Electroencephalographic aspects of minimal brain dysfunction

Os AA analisaram 50 casos de pacientes portadores de disfunçäo cerebral mínima e concluíram que o eletroencefalograma pode ser normal ou exteriorizar (1) atividade lenta posterior; (2) assimetria e assincronia da atividade; (3) descargas na faixa "theta" com ondas de morfologia espiculada e distribuiçäo difusa; (4) ondas de morfologia espiculada no lobo temporal; (5) complexo ponta-onda difuso

Aspectos eletroencefalograficos na disfuncao cerebral minima

Os AA analisaram 50 casos de pacientes portadores de disfuncao cerebral minima e concluiram que o eletroencefalograma pode ser normal ou exteriorizar (1) atividade lenta posterior; (2) assimetria e assincronia da atividade; (3) descargas na faixa 'theta' com ondas de mprfologia espiculada e distribuicao difusa; (4) ondas de morfologia espiculada no lobo temporal; (5) complexo ponta-onda difuso.

Disfunçäo cerebral mínima / Minimal brain dysfunction

Nossa casuística consiste de cinqüenta casos de disfunçäo cerebral mínima retirados de maneira näo selecionada, entre aqueles que foram avaliados e acompanhados por nós, durante o período de maio de 1975 a maio de 1983. Verificamos predominância do sexo masculino sobre o feminino em torno de 3:1, e maior freqüência de pacientes de cor branca. O desenvolvimento da sintomatologia pode ocorrer em qualquer faixa etária, sendo mais freqüente na idade pré-escolar entre seis e oito anos. As manifestaçöes clínicas predominantes foram a hiperatividade, alteraçöes do sono e dificuldade de aprendizagem

Disfuncao cerebral minima

Nossa casuistica consiste de cinquenta casos de disfuncao cerebral minima retirados de maneira nao selecionada, entre aqueles que foram avaliados e acompanhados por nos, durante o periodo de maio de 1975 a maio de 1983. Verificamos predominancia do sexo masculino sobre o feminino em torno de 3:1, e maior frequencia de pacientes de cor branca. O desenvolvimento da sintomatologia pode ocorrer em qualquer faixa etaria, sendo mais frequente na idade pre-escolar entre seis e oito anos. As manifestacoes clinicas predominantes foram a hiperatividade, alteracoes do sono e dificuldade de aprendizagem.

Vascularizaçäo da medula espinhal do gambá / Vascular supply of the opossum's spinal cord

A medula espinhal do gambá (Didelphis marsupialis aurita) apresenta na face ventral três e na face dorsal duas artérias e no mínimo três veias com disposiçäo crânio-caudal. Os vasos radiculares anastomosam-se com os vasos espinhais dorsais e ventrais. As veias dos segmentos cervicais dirigem-se para os seios venosos da dura-máter. Os vasos centrais (sulco-comissurais) penetram na mudula espinhal pela fissura mediana ventral e, ao nível da comissura branca ventral, curvam-se, em geral alternadamente, em direçäo à cabeça da coluna cinzenta ventral. Outros vasos penetram pelas faces ventral, lateral e dorsal da medula espinhal. Cada artéria intramedular tem a seu lado uma veia, formando pares vasculares que näo se anastomosam entre si. Os capilares formados do encontro das arteríolas com as vênulas dos pares vasculares terminais adquirem o formato de alças

Vascularizacao da medula espinhal do gamba

A medula espinhal do gamba (Didelphis marsupialis aurita) apresenta na face ventral tres veias e na face dorsal duas arterias e no minimo tres veias com disposicao cranio-caudal. Os vasos radiculares anastomosam-se com os vasos espinhais dorsais e ventrais. As veias dos segmentos cervicais dirigem-se para os seios venosos da dura-mater. Os vasos centrais (sulco-comissurais) penetram na mudula espinhal pela fissura mediana ventral e, ao nivel da comissura branca ventral, curvam-se, em geral alternadamente, em direcao a cabeca da coluna cinzenta ventral. Outros penetram pelas faces ventral, lateral e dorsal da medula espinhal. Cada arteria intramedular tem a seu lado uma veia, formando pares vasculares que nao se anastomosam entre si. Os capilares formados do encontro das arteriolas com as venulas dos pares vasculares terminais adquirem o formato de alcas.

Condromas intracranianos

Os autores apresentam um caso de condroma intracraniano. Os exames complementares, radiografia simples de cranio, angiografia carotidea e tomografia computadorizada de cranio evidenciaram o tumor. O tratamento consistiu na excisao cirurgica, com a retirada do neoplasma, de natureza cartilaginosa. A estrutura hispotalogica mostrou ser um condroma.