Expression, crystallization and preliminary X-ray crystallographic analysis of glucose-6-phosphate dehydrogenase from the human pathogen Trypanosoma cruzi in complex with substrate. Corrigendum

A correction to the article by Ortíz et al. [(2011), Acta Cryst. F67, 1457–1461]

Murine colon organoids as a novel model to study Trypanosoma cruzi infection and interactions with the intestinal epithelium

Chagas disease (CD) is a life-threatening illness caused by the parasite Trypanosoma cruzi (T. cruzi). With around seven million people infected worldwide and over 50,000 deaths per year, CD is a major public health issue in Latin America. The main route of transmission to humans is through a triatomine bug (vector-borne), but congenital and oral transmission have also been reported. The acute phase of CD presents mild symptoms but may develop into a long-lasting chronic illness, characterized by severely impaired cardiac, digestive, and neurological functions. The intestinal tissue appears to have a key role during oral transmission and chronic infection of CD. In this immune-privileged reservoir, dormant/quiescent parasites have been suggested to contribute to disease persistence, infection relapse, and treatment failure. However, the interaction between the intestinal epithelium and T. cruzi has not been examined in depth, in part, due to the lack of in vitro models that approximate to the biological and structural complexity of this tissue. Therefore, to understand the role played by the intestinal tissue during transmission and chronic infection, physiological models resembling the organ complexity are needed. Here we addressed this issue by establishing and characterizing adult stem cell-derived colonoid infection models that are clinically relevant for CD. 3D and 2D systems of murine intestinal organoids infected with T. cruzi Dm28c (a highly virulent strain associated with oral outbreaks) were analyzed at different time points by confocal microscopy. T. cruzi was able to invade and replicate in intestinal epithelial primary cells grown as intact organoids (3D) and monolayers (2D). The permissiveness to pathogen infection differed markedly between organoids and cell lines (primate and intestinal human cell lines). So far, this represents the first evidence of the potential that these cellular systems offer for the study of host-pathogen interactions and the discovery of effective anti-chagasic drugs.Agencia Nacional de Investigación e InnovaciónPasteur NetworkFOCEM (MERCOSUR Structural Convergence Fund

Modeling host-parasite interaction in chagas disease with murine intestinal organoids

Chagas disease (CD) is a potentially life-threatening illness caused by the parasite Trypanosoma cruzi (T. cruzi). With around seven million people infected worldwide and over 10,000 deaths per year, CD is a major public health issue in Latin America. The main route of transmission to humans is through a triatomine bug (vector-borne) and, to a minor extent, by blood transfusion, organ transplantation, laboratory accidents, congenitally and orally (food-borne). The acute phase of CD presents mild symptoms. If left untreated, it develops into a long-lasting chronic illness, characterized by severely impaired cardiac, digestive, and neurological functions. The intestinal tissue appears to have a key role during oral transmission and chronic infection of CD. In these immune-privileged reservoirs, dormant/quiescent parasites have been suggested to contribute to disease persistence, infection relapse, and treatment failure. However, the interaction between the intestinal epithelium and T. cruzi has not been examined in depth, in part, due to the lack of in vitro models resembling the biological and structural complexity of this organ. Therefore, to understand the pathophysiological role played by the intestinal tissue during transmission and chronic infection, we evaluated the progression of T. cruzi infection of murine colon organoids. In order to model CD, 3D and 2D systems of murine intestinal organoids were infected with T. cruzi Dm28c, a strain that has been associated with high virulence and oral outbreaks. At different time points, the presence and load of parasites in the organoids, as well as the host cell morphology were evaluated by confocal microscopy, and compared to those obtained with a classical infection model (Vero cells). We show that the parasite invades and replicates in intestinal epithelial primary cells grown as intact organoids (3D) and monolayers (2D). The permissiveness to pathogen infection differed markedly between the primary and the tumoral (Vero) cells. So far, this represents the first evidence of the potential of these nearly physiological cellular systems to study host-pathogen interaction for CD and/or for the future evaluation of anti-chagasic drugs.Agencia Nacional de Investigación e Innovación (ANII)FOCEM (MERCOSUR Structural Convergence Fund

Nox2-derived superoxide radical is crucial to control acute Trypanosoma cruzi infection

Carolina Prolo: Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Centro de Investigaciones Biomédicas (CEINBIO), Facultad de Medicina, Universidad de la República, Montevideo, Uruguay -- Damián Estrada: Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Centro de Investigaciones Biomédicas (CEINBIO), Facultad de Medicina, Universidad de la República, Montevideo, Uruguay -- Lucía Piacenza: Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay -- Diego Benítez: Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Uruguay -- Marcelo A. Comini: Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Uruguay -- Rafael Radi: Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Centro de Investigaciones Biomédicas (CEINBIO), Facultad de Medicina, Universidad de la República, Montevideo, Uruguay -- María Noel Álvarez: Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Centro de Investigaciones Biomédicas (CEINBIO), Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Departamento de Educación Médica, Facultad de Medicina, Universidad de la República, Montevideo, UruguayTrypanosoma cruzi is a flagellated protozoan that undergoes a complex life cycle between hematophagous insects and mammals. In humans, this parasite causes Chagas disease, which in thirty percent of those infected, would result in serious chronic pathologies and even death. Macrophages participate in the first stages of infection, mounting a cytotoxic response which promotes massive oxidative damage to the parasite. On the other hand, T. cruzi is equipped with a robust antioxidant system to repeal the oxidative attack from macrophages. This work was conceived to explicitly assess the role of mammalian cell-derived superoxide radical in a murine model of acute infection by T. cruzi. Macrophages derived from Nox2-deficient (gp91phox-/-) mice produced marginal amounts of superoxide radical and were more susceptible to parasite infection than those derived from wild type (wt) animals. Also, the lack of superoxide radical led to an impairment of parasite differentiation inside gp91phox-/- macrophages. Biochemical or genetic reconstitution of intraphagosomal superoxide radical formation in gp91phox-/- macrophages reverted the lack of control of infection. Along the same line, gp91phox-/- infected mice died shortly after infection. In spite of the higher lethality, parasitemia did not differ between gp91phox-/- and wt animals, recapitulating an observation that has led to conflicting interpretations about the importance of the mammalian oxidative response against T. cruzi. Importantly, gp91phox-/- mice presented higher and disseminated tissue parasitism, as evaluated by both qPCR- and bioimaging-based methodologies. Thus, this work supports that Nox2-derived superoxide radical plays a crucial role to control T. cruzi infection in the early phase of a murine model of Chagas disease

A FRET-based cGMP biosensor in Drosophila

CUTie2 is a FRET-based cGMP biosensor tested so far only in cells. To expand its use to multicellular organisms we generated two transgenic Drosophila melanogaster strains that express the biosensor in a tissue-dependent manner. CUTie2 expression and subcellular localization was verified by confocal microscopy. The performance of CUTie2 was analyzed on dissected larval brains by hyperspectral microscopy and flow cytometry. Both approaches confirmed its responsivity, and the latter showed a rapid and reversible change in the fluorescence of the FRET acceptor upon cGMP treatment. This validated reporter system may prove valuable for studying cGMP signaling at organismal level.Agencia Nacional de Investigación e InnovaciónDirección Nacional de Innovación, Ciencia y Tecnologí

Potencial de los organoides intestinales murinos para el estudio de la enfermedad de Chagas

Chagas disease (CD) is a potentially life-threatening illness caused by the parasite Trypanosoma cruzi (T. cruzi). With around seven million people infected worldwide and over 10,000 deaths per year, CD is a major public health issue in Latin America. The main route of transmission to humans is through a triatomine bug (vector-borne) and, to a minor extent, by blood transfusion, organ transplantation, laboratory accidents, congenitally and orally (food- borne). The acute phase of CD presents mild symptoms. If left untreated, it develops into a long-lasting chronic illness, characterized by severely impaired cardiac, digestive, and neurological functions. The intestinal tissue appears to have a key role during oral transmission and chronic infection of CD. In these immune-privileged reservoirs, dormant/quiescent parasites have been suggested to contribute to disease persistence, infection relapse, and treatment failure. However, the interaction between the intestinal epithelium and T. cruzi has not been examined in depth, in part, due to the lack of in vitro models resembling the biological and structural complexity of this organ. Therefore, to understand the pathophysiological role played by the intestinal tissue during transmission and chronic infection, we evaluated the progression of T. cruzi infection of murine colon organoids. In order to model CD, 3D and 2D systems of murine intestinal organoids were infected with T. cruzi Dm28c, a strain that has been associated with high virulence and oral outbreaks. At different time points, the presence and load of parasites in the organoids, as well as the host cell morphology were evaluated by confocal microscopy, and compared to those obtained with a classical infection model (Vero cells). We show that the parasite invades and replicates in intestinal epithelial primary cells grown as intact organoids (3D) and monolayers (2D). The permissiveness to pathogen infection differed markedly between the primary and the tumoral (Vero) cells. So far, this represents the first evidence of the potential of these nearly physiological cellular systems to study host-pathogen interaction for CD and/or for the future evaluation of anti-chagasic drugs.Agencia Nacional de Investigación e Innovación (ANII

PAYMENTS FOR ENVIRONMENTAL SERVICES (PES): CHALLENGES AND OPPORTUNITIES FOR RURAL PRODUCERS AT SENHORA DE OLIVEIRA, MINAS GERAIS

Payment for Environmental Services (PES) is an important tool for environmental conservation and is a relevant practice in many countries for the maintenance of forests. Thus, the objective of the present study was to evaluate challenges and opportunities of implementing a Payment for Environmental Services program in the municipality of Senhora de Oliveira, Minas Gerais. Socioeconomic and environmental diagnosis was performed using the Rapid Participatory Diagnosis technique. The total of 20 socioeconomic and environmental questionnaires were applied in the municipality, aiming to know in detail the local reality, raising potentialities and demands. The number of members of the 20 families that participated in the rural diagnosis was 72, of which 36 were men and 36 were women, with an average of 3.6 persons per family. Of the 20 rural properties that participated in the rural diagnosis, 35% have delimited RL areas and none of them has a management plan. The exploration of Legal Reserve occurs in 15% of the evaluated properties, being the production of firewood and cuttings the predominant activity. The average value of disposition receivable by rural producers was R$ 220.00 ha-1year-1, in which the producers who did not respond to this question were not considered. The municipality of Senhora de Oliveira, Minas Gerais has the necessary conditions to implement the PES, however the producers still do not receive any incentive to provide environmental services. If this process of PES is implemented, there will certainly be advances in environmental conservation and will bring social benefits throughout the region

The lineage-specific, intrinsically disordered N-terminal extension of monothiol glutaredoxin 1 from trypanosomes contains a regulatory region

Glutaredoxins (Grx) are small proteins conserved throughout all the kingdoms of life that are engaged in a wide variety of biological processes and share a common thioredoxin-fold. Among them, class II Grx are redox-inactive proteins involved in iron-sulfur (FeS) metabolism. They contain a single thiol group in their active site and use low molecular mass thiols such as glutathione as ligand for binding FeS-clusters. In this study, we investigated molecular aspects of 1CGrx1 from the pathogenic parasite Trypanosoma brucei brucei, a mitochondrial class II Grx that fulfills an indispensable role in vivo. Mitochondrial 1CGrx1 from trypanosomes differs from orthologues in several features including the presence of a parasite-specific N-terminal extension (NTE) whose role has yet to be elucidated. Previously we have solved the structure of a truncated form of 1CGrx1 containing only the conserved glutaredoxin domain but lacking the NTE. Our aim here is to investigate the effect of the NTE on the conformation of the protein. We therefore solved the NMR structure of the full-length protein, which reveals subtle but significant differences with the structure of the NTE-less form. By means of different experimental approaches, the NTE proved to be intrinsically disordered and not involved in the non-redox dependent protein dimerization, as previously suggested. Interestingly, the portion comprising residues 65–76 of the NTE modulates the conformational dynamics of the glutathione-binding pocket, which may play a role in iron-sulfur cluster assembly and delivery. Furthermore, we disclosed that the class II-strictly conserved loop that precedes the active site is critical for stabilizing the protein structure. So far, this represents the first communication of a Grx containing an intrinsically disordered region that defines a new protein subgroup within class II Grx

Trypanothione synthetase confers growth, survival advantage and resistance to anti-protozoal drugs in Trypanosoma cruzi

Background: Chagas cardiomyopathy, caused by Trypanosoma cruzi infection, continues to be a neglected illness, and has a major impact on global health. The parasite undergoes several stages of morphological and biochemical changes during its life cycle, and utilizes an elaborated antioxidant network to overcome the oxidants barrier and establish infection in vector and mammalian hosts. Trypanothione synthetase (TryS) catalyzes the biosynthesis of glutathione-spermidine adduct trypanothione (T(SH)2) that is the principal intracellular thiol-redox metabolite in trypanosomatids. Methods and Results: We utilized genetic overexpression (TryShi) and pharmacological inhibition approaches to examine the role of TryS in T. cruzi proliferation, tolerance to oxidative stress and resistance to anti-protozoal drugs. Our data showed the expression and activity of TryS was increased in all morphological stages of TryShi (vs. control) parasites. In comparison to controls, the TryShi epimastigotes (insect stage) recorded shorter doubling time, and both epimastigotes and infective trypomastigotes of TryShi exhibited 36-71% higher resistance to H2O2 (50-1000 M) and heavy metal (1-500 M) toxicity. Treatment with TryS inhibitors (5-30 M) abolished the proliferation and survival advantages against H2O2 pressure in a dose-dependent manner in both TryShi and control parasites. Further, epimastigote and trypomastigote forms of TryShi (vs. control) T. cruzi tolerated higher doses of benznidazole and nifurtimox, the drugs currently administered for acute Chagas disease treatment. Conclusions: TryS is essential for proliferation and survival of T. cruzi under normal and oxidant stress conditions, and provides an advantage to the parasite to develop resistance against currently used antitrypanosomal drugs. TryS indispensability has been chemically validated with inhibitors that may be useful for drug combination therapy against Chagas disease.Fil: Mesias, Andrea Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: Sasoni, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Arias, Diego Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Pérez Brandan, Cecilia María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: Orban, Oliver C. F.. Technische Universitat Carolo Wilhelmina Zu Braunschweig.; AlemaniaFil: Kunick, Conrad. Technische Universitat Carolo Wilhelmina Zu Braunschweig.; AlemaniaFil: Robello, Carlos. Instituto Pasteur de Montevideo; UruguayFil: Comini, Marcelo. Instituto Pasteur de Montevideo; UruguayFil: Garg, Nisha J.. University of Texas Medical Branch; Estados UnidosFil: Zago, María Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; Argentin