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Nematode infections affect a fifth of the human population, livestock, and crops worldwide, imposing a burden to global public health and economies, particularly in developing nations. Resistance to commercial anthelmintics has increased over the years in livestock infections and driven the pursuit for new drugs. We herein present a rapid, cost-effective, and automated assay for nematicide discovery using the free-living nematode Caenorhabditis elegans to screen a highly diverse natural product library enriched in bioactive molecules. Screening of 10,240 fractions obtained from extracts of various biological sources allowed the identification of 7 promising hit fractions, all from marine sponges. These fractions were further assayed for nematicidal activity against the sheep nematode parasite Haemonchus contortus and for innocuity in zebrafish. The most active extracts against parasites and innocuous toward vertebrates belong to two chemotypes. High-performance liquid chromatography (HPLC) coupled with nuclear magnetic resonance (NMR) revealed that the most abundant compound in one chemotype is halaminol A, an aminoalcohol previously identified in a small screen against H. contortus. Terpene-nucleotide hybrids known as agelasines predominate in the other chemotype. This study reinforces the power of C. elegans for nematicide discovery from large collections and the potential of the chemical diversity derived from marine invertebrate biota.
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Antinematódeos , Caenorhabditis elegans , Poríferos , Animais , Poríferos/química , Antinematódeos/farmacologia , Antinematódeos/química , Caenorhabditis elegans/efeitos dos fármacos , Estrutura Molecular , Peixe-Zebra , Haemonchus/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão/métodosRESUMO
Aims: To determine the role of the kynurenine (KYN) pathway in rhodoquinone (RQ) and de novo NAD+ biosynthesis and whether NAD+ rescue pathways are essential in parasitic worms (helminths). Results: We demonstrate that RQ, the key electron transporter used by helminths under hypoxia, derives from the tryptophan (Trp) catabolism even in the presence of a minimal KYN pathway. We show that of the KYN pathway genes only the kynureninase and tryptophan/indoleamine dioxygenases are essential for RQ biosynthesis. Metabolic labeling with Trp revealed that the lack of the formamidase and kynurenine monooxygenase genes did not preclude RQ biosynthesis in the flatworm Mesocestoides corti. In contrast, a minimal KYN pathway prevented de novo NAD+ biosynthesis, as revealed by metabolic labeling in M. corti, which also lacks the 3-hydroxyanthranilate 3,4-dioxygenase gene. Our results indicate that most helminths depend solely on NAD+ rescue pathways, and some lineages rely exclusively on the nicotinamide salvage pathway. Importantly, the inhibition of the NAD+ recycling enzyme nicotinamide phosphoribosyltransferase with FK866 led cultured M. corti to death. Innovation: We use comparative genomics of more than 100 hundred helminth genomes, metabolic labeling, HPLC-mass spectrometry targeted metabolomics, and enzyme inhibitors to define pathways that lead to RQ and NAD+ biosynthesis in helminths. We identified the essential enzymes of these pathways in helminth lineages, revealing new potential pharmacological targets for helminthiasis. Conclusion: Our results demonstrate that a minimal KYN pathway was evolutionary maintained for RQ and not for de novo NAD+ biosynthesis in helminths and shed light on the essentiality of NAD+ rescue pathways in helminths.
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INTRODUCTION: Metabolic associated steatohepatitis (MASH) is one of the most frequent causes of chronic liver disease. Liver transaminases are important biomarkers to measure liver injury, however, a proportion of patients with MASH may present with normal levels of transaminases. The levels of serum transaminases may not correlate with the severity of histopathological changes. OBJECTIVE: We aimed to identify the frequency of normal transaminases in obese patients with MASH, as well as to describe the clinical, biochemical and histological characteristics in this specific group of patients. MATERIALS AND METHODS: A retrospective cross-sectional study was conducted in the bariatric surgery service of a private clinic. Obese patients older than 18 years with a body mass index (BMI) >30Kg/m2 and 2 co-morbidities undergoing a gastric sleeve surgery were included. Measurement of biochemical routine laboratory exams was performed. Insulin resistance was calculated using the homeostasis evaluation model (HOMA-IR). All patients underwent liver biopsies prior to surgery and the diagnosis of MASH was based on the Brunt criteria. RESULTS: 159 obese patients with MASH were included, of which 47.2% had normal transaminases and 52.8% elevated transaminases. Factors associated with alteration in transaminases were: being male OR=4.02 (95% CI: 2.03- 7.96; p<0.01), diagnosis of type 2 diabetes mellitus OR=4.86 (95% CI: 1.97- 11.95; p<0.01) and levels of GGT >50 IU/L OR=7.50 (95% CI: 3.40-16.56; p<0.01). The values of HOMA-IR and GGT were significantly higher in the group of high transaminases (p<0.01). Differences in the degree of fibrosis were not associated with transaminases levels. CONCLUSION: In conclusion we found that the frequency of normal transaminases was 47.2% in obese patients with MASH. Factors associated with elevation in liver enzymes were being male, diagnosis of diabetes mellitus and elevation in GGT levels. The degree of fibrosis was not associated with elevations in liver transaminases. These findings suggest that transaminases levels alone are not accurate markers to assess liver injury, as they do not necessarily correlate with histological liver damage.
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Diabetes Mellitus Tipo 2 , Fígado Gorduroso , Hepatopatias , Hepatopatia Gordurosa não Alcoólica , Obesidade Mórbida , Humanos , Masculino , Feminino , Transaminases , Estudos Retrospectivos , Estudos Transversais , Diabetes Mellitus Tipo 2/complicações , Peru , Fígado Gorduroso/diagnóstico , Obesidade/complicações , Hepatopatia Gordurosa não Alcoólica/complicações , Hepatopatia Gordurosa não Alcoólica/diagnóstico , Obesidade Mórbida/complicações , Obesidade Mórbida/cirurgiaRESUMO
Caenorhabditis elegans is a free-living nematode that has been validated for anthelmintic drug screening. However, this model has not been used to address anthelmintic dose-response-time and drug-drug interactions through matrix array methodology. Eprinomectin (EPM) and Ivermectin (IVM) are macrocyclic lactones widely used as anthelmintics. Despite being very similar, EPM and IVM are combined in commercial formulations or mixed by farmers, under the assumption that the combination would increase their efficacy. However, there is no data reported on the pharmacological evaluation of the combination of both drugs. In this study, we assessed the pharmacodynamics and drug-drug interactions of these two anthelmintic drugs. Since the action of these drugs causes worm paralysis, we used an infrared motility assay to measure EPM and IVM effects on worm movement over time. The results showed that EPM was slightly more potent than IVM, that drug potency increased with drug time exposure, and that once paralyzed, worms did not recover. Different EPM/IVM concentration ratios were used and synergy and combination sensitivity scores were determined at different exposure times, applying Highest Single Agent (HSA), Loewe additivity, Bliss and Zero Interaction Potency (ZIP) models. The results clearly indicate that there is neither synergy nor antagonism between both macrocyclic lactones. This study shows that it is more relevant to prioritize the exposure time of each individual drug than to combine them to improve their effects. The results highlight the utility of C. elegans to address pharmacodynamics studies, particularly for drug-drug interactions. Models in vitro can be integrated to facilitate preclinical and clinical translational studies and help researchers to understand drug-drug interactions and achieve rational therapeutic regimes.
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A recent screen of 67,012 compounds identified a new family of compounds with excellent nematicidal activity: the ortho-substituted benzamide families Wact-11 and Wact-12. These compounds are active against Caenorhabditis elegans and parasitic nematodes by selectively inhibiting nematode complex II, and they display low toxicity in mammalian cells and vertebrate organisms. Although a big number of benzamides were tested against C. elegans in high-throughput screens, bioisosteres of the amide moiety were not represented in the chemical space examined. We thus identified an opportunity for the design, synthesis and evaluation of novel compounds, using bioisosteric replacements of the amide group present in benzamides. The compound Wact-11 was used as the reference scaffold to prepare a set of bioisosteres to be evaluated against C. elegans. Eight types of amide replacement were selected, including ester, thioamide, selenoamide, sulfonamide, alkyl thio- and oxo-amides, urea and triazole. The results allowed us to perform a structure-activity relationship, highlighting the relevance of the amide group for nematicide activity. Experimental evidence was complemented with in silico structural studies over a C. elegans complex II model as a molecular target of benzamides. Importantly, compound Wact-11 was active against the flatworm Echinococcus granulosus, suggesting a previously unreported pan-anthelmintic potential for benzamides.
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Anti-Helmínticos , Caenorhabditis elegans , Amidas , Animais , Anti-Helmínticos/química , Anti-Helmínticos/farmacologia , Antinematódeos/farmacologia , Benzamidas/farmacologia , MamíferosRESUMO
Introduction: Metabolic associated steatohepatitis (MASH) is one of the most frequent causes of chronic liver disease. Liver transaminases are important biomarkers to measure liver injury, however, a proportion of patients with MASH may present with normal levels of transaminases. The levels of serum transaminases may not correlate with the severity of histopathological changes. Objective: We aimed to identify the frequency of normal transaminases in obese patients with MASH, as well as to describe the clinical, biochemical and histological characteristics in this specific group of patients. Materials and methods: A retrospective cross-sectional study was conducted in the bariatric surgery service of a private clinic. Obese patients older than 18 years with a body mass index (BMI) >30Kg/m2 and 2 co-morbidities undergoing a gastric sleeve surgery were included. Measurement of biochemical routine laboratory exams was performed. Insulin resistance was calculated using the homeostasis evaluation model (HOMA-IR). All patients underwent liver biopsies prior to surgery and the diagnosis of MASH was based on the Brunt criteria. Results: 159 obese patients with MASH were included, of which 47.2% had normal transaminases and 52.8% elevated transaminases. Factors associated with alteration in transaminases were: being male OR=4.02 (95% CI: 2.037.96; p50 IU/L OR=7.50 (95% CI: 3.40-16.56; p<0.01). The values of HOMA-IR and GGT were significantly higher in the group of high transaminases (p<0.01). Differences in the degree of fibrosis were not associated with transaminases levels. Conclusion: In conclusion we found that the frequency of normal transaminases was 47.2% in obese patients with MASH. Factors associated with elevation in liver enzymes were being male, diagnosis of diabetes mellitus and elevation in GGT levels. The degree of fibrosis was not associated with elevations in liver transaminases. These findings suggest that transaminases levels alone are not accurate markers to assess liver injury, as they do not necessarily correlate with histological liver damage.
Introducción: La esteatohepatitis asociada metabólica (MASH) es una de las causas más frecuentes de enfermedad hepática crónica. Las transaminasas hepáticas son biomarcadores importantes para medir el daño hepático; sin embargo, una proporción de pacientes con MASH pueden presentar niveles normales de transaminasas. Los niveles de transaminasas séricas pueden no estar correlacionados con la gravedad de los cambios histopatológicos. Objetivo: Nuestro objetivo fue identificar la frecuencia de transaminasas normales en pacientes obesos con MASH, así como describir las características clínicas, bioquímicas e histológicas en este grupo específico de pacientes. Materiales y métodos: Se realizó un estudio transversal retrospectivo en el servicio de cirugía bariátrica de una clínica privada. Se incluyeron pacientes obesos mayores de 18 años con índice de masa corporal (IMC) >30Kg/m2 y 2 comorbilidades sometidos a cirugía de manga gástrica. Se realizó la medición de los exámenes bioquímicos de laboratorio de rutina. La resistencia a la insulina se calculó mediante el modelo de evaluación de la homeostasis (HOMA-IR). Todos los pacientes se sometieron a biopsias hepáticas antes de la cirugía y el diagnóstico de MASH se basó en los criterios de Brunt. Resultados: Se incluyeron 159 pacientes obesos con MASH, de los cuales el 47,2% tenían transaminasas normales y el 52,8% transaminasas elevadas. Los factores asociados a la alteración de las transaminasas fueron: ser hombre OR=4,02 (IC 95%: 2,03-7,96; p50 UI/L OR=7,50 (IC 95%: 3,40-16,56; p<0,01). Los valores de HOMA-IR y GGT fueron significativamente mayores en el grupo de transaminasas altas (p<0,01). Las diferencias en el grado de fibrosis no se asociaron con los niveles de transaminasas. Conclusión: Encontramos que la frecuencia de transaminasas normales fue del 47,2% en pacientes obesos con MASH. Los factores asociados con la elevación de las enzimas hepáticas fueron el sexo masculino, el diagnóstico de diabetes mellitus y la elevación de los niveles de GGT. El grado de fibrosis no se asoció con elevaciones de las transaminasas hepáticas. Estos hallazgos sugieren que los niveles de transaminasas por sí solos no son marcadores precisos para evaluar el daño hepático, ya que no necesariamente se correlacionan con el daño hepático histológico.
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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the current coronavirus disease 2019 (COVID-19) pandemic, affecting more than 219 countries and causing the death of more than 5 million people worldwide. The genetic background represents a factor that predisposes the way the host responds to SARS-CoV-2 infection. In this sense, genetic variants of ACE and ACE2 could explain the observed interindividual variability to COVID-19 outcomes. In order to improve the understanding of how genetic variants of ACE and ACE2 are involved in the severity of COVID-19, we included a total of 481 individuals who showed clinical manifestations of COVID-19 and were diagnosed by reverse transcription PCR (RT-PCR). Genomic DNA was extracted from peripheral blood and saliva samples. ACE insertion/deletion polymorphism was evaluated by the high-resolution melting method; ACE single-nucleotide polymorphism (SNP) (rs4344) and ACE2 SNPs (rs2285666 and rs2074192) were genotyped using TaqMan probes. We assessed the association of ACE and ACE2 polymorphisms with disease severity using logistic regression analysis adjusted by age, sex, hypertension, type 2 diabetes, and obesity. The severity of the illness in our study population was divided as 31% mild, 26% severe, and 43% critical illness; additionally, 18% of individuals died, of whom 54% were male. Our results showed in the codominant model a contribution of ACE2 gene rs2285666 T/T genotype to critical outcome [odds ratio (OR) = 1.83; 95%CI = 1.01-3.29; p = 0.04] and to require oxygen supplementation (OR = 1.76; 95%CI = 1.01-3.04; p = 0.04), in addition to a strong association of the T allele of this variant to develop critical illness in male individuals (OR = 1.81; 95%CI = 1.10-2.98; p = 0.02). We suggest that the T allele of rs2285666 represents a risk factor for severe and critical outcomes of COVID-19, especially for men, regardless of age, hypertension, obesity, and type 2 diabetes.
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Enzima de Conversão de Angiotensina 2/genética , COVID-19/genética , Peptidil Dipeptidase A/genética , Polimorfismo de Nucleotídeo Único/genética , Alelos , COVID-19/virologia , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/virologia , Genótipo , Humanos , Masculino , SARS-CoV-2/patogenicidadeRESUMO
Parasitic nematodes constitute a health problem for humans, livestock and crops, and cause huge economic losses to developing-country economies. Due to the spread of nematicide resistance, there is an urgent need for new drugs. C. elegans is now recognized as a cost-effective alternative for the screening of compound libraries with potential nematicidal activity, as parasitic organisms are hard to maintain under laboratory conditions. Here we describe an adaptation of a previously reported high throughput (HTP) infrared-based motility assay that leads to increased sensitivity. The modified assay uses L1 instead of L4 stage worms and matches the sensitivity reported by Burns et al. (2015) for the anthelmintic benzamides Wact11 and Wact11p. In addition, this method presents practical advantages over Burns et al. (2015) and other image-based protocols and provides a robust assay with a fast and simple readout ideal for HTP drug discovery.
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Five heteroleptic compounds, [VVO(IN-2H)(L-H)], where L are 8-hydroxyquinoline derivatives and IN is a Schiff base ligand, were synthesized and characterized in both the solid and solution state. The compounds were evaluated on epimastigotes and trypomastigotes of Trypanosoma cruzi as well as on VERO cells, as a mammalian cell model. Compounds showed activity against trypomastigotes with IC50 values of 0.29-3.02 µM. IN ligand and the new [VVO2(IN-H)] complex showed negligible activity. The most active compound [VVO(IN-2H)(L2-H)], with L2 = 5-chloro-7-iodo-8-hydroxyquinoline, showed good selectivity towards the parasite and was selected to carry out further biological studies. Stability studies suggested a partial decomposition in solution. [VVO(IN-2H)(L2-H)] affects the infection potential of cell-derived trypomastigotes. Low total vanadium uptake by parasites and preferential accumulation in the soluble proteins fraction were determined. A trypanocide effect was observed when incubating epimastigotes with 10 × IC50 values of [VVO(IN-2H)(L2-H)] and the generation of ROS after treatments was suggested. Fluorescence competition measurements with DNA:ethidium bromide adduct showed a moderate DNA interaction of the complexes. In vivo toxicity study on C. elegans model showed no toxicity up to a 100 µM concentration of [VVO(IN-2H)(L2-H)]. This compound could be considered a prospective anti-T. cruzi agent that deserves further research.
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Caenorhabditis elegans/efeitos dos fármacos , Complexos de Coordenação/farmacologia , Oxiquinolina/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Vanádio/farmacologia , Animais , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Estrutura Molecular , Oxiquinolina/química , Testes de Sensibilidade Parasitária , Tripanossomicidas/síntese química , Tripanossomicidas/química , Vanádio/químicaRESUMO
The terpenoid benzoquinone, rhodoquinone (RQ), is essential to the bioenergetics of many organisms that survive in low oxygen environments. RQ biosynthesis and its regulation has potential as a novel target for anti-microbial and anti-parasitic drug development. Recent work has uncovered two distinct pathways for RQ biosynthesis which have evolved independently. The first pathway is used by bacteria, such as Rhodospirillum rubrum, and some protists that possess the rquA gene. These species derive their RQ directly from ubiquinone (UQ), the essential electron transporter used in the aerobic respiratory chain. The second pathway is used in animals, such as Caenorhabditis elegans and parasitic helminths, and requires 3-hydroxyanthranilic acid (3-HAA) as a precursor, which is derived from tryptophan through the kynurenine pathway. A COQ-2 isoform, which is unique to these species, facilitates prenylation of the 3-HAA precursor. After prenylation, the arylamine ring is further modified to form RQ using several enzymes common to the UQ biosynthetic pathway. In addition to current knowledge of RQ biosynthesis, we review the phylogenetic distribution of RQ and its function in anaerobic electron transport chains in bacteria and animals. Finally, we discuss key steps in RQ biosynthesis that offer potential as drug targets to treat microbial and parasitic infections, which are rising global health concerns.
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Bactérias/metabolismo , Vias Biossintéticas , Elétrons , Metabolismo Energético , Ubiquinona/análogos & derivados , Anaerobiose , Animais , Transporte de Elétrons , Ubiquinona/metabolismoRESUMO
Selenium is a trace element for most organisms; its deficiency and excess are detrimental. Selenium beneficial effects are mainly due to the role of the 21st genetically encoded amino acid selenocysteine (Sec). Selenium also exerts Sec-independent beneficial effects. Its harmful effects are thought to be mainly due to non-specific incorporation in protein synthesis. Yet the selenium response in animals is poorly understood. In Caenorhabditis elegans, Sec is genetically incorporated into a single selenoprotein. Similar to mammals, a 20-fold excess of the optimal selenium requirement is harmful. Sodium selenite (Na2SeO3) excess causes development retardation, impaired growth, and neurodegeneration of motor neurons. To study the organismal response to selenium we performed a genetic screen for C. elegans mutants that are resistant to selenite. We isolated non-sense and missense egl-9/EGLN mutants that confer robust resistance to selenium. In contrast, hif-1/HIF null mutant was highly sensitive to selenium, establishing a role for this transcription factor in the selenium response. We showed that EGL-9 regulates HIF-1 activity through VHL-1, and identified CYSL-1 as a key sensor that transduces the selenium signal. Finally, we showed that the key enzymes involved in sulfide and sulfite stress (sulfide quinone oxidoreductase and sulfite oxidase) are not required for selenium resistance. In contrast, knockout strains in the persulfide dioxygenase ETHE-1 and the sulfurtransferase MPST-7 affect the organismal response to selenium. In sum, our results identified a transcriptional pathway as well as enzymes possibly involved in the organismal selenium response.
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Helminths use an alternative mitochondrial electron transport chain (ETC) under hypoxic conditions, such as those found in the gastrointestinal tract. In this alternative ETC, fumarate is the final electron acceptor and rhodoquinone (RQ) serves as an electron carrier. RQ receives electrons from reduced nicotinamide adenine dinucleotide through complex I and donates electrons to fumarate through complex II. In this latter reaction, complex II functions in the opposite direction to the conventional ETC (i.e., as fumarate reductase instead of succinate dehydrogenase). Studies in Ascaris suum indicate that this is possible due to changes in complex II, involving alternative succinate dehydrogenase (SDH) subunits SDHA and SDHD, derived from duplicated genes. We analyzed helminth genomes and found that distinct lineages have different gene duplications of complex II subunits (SDHA, SDHB, SDHC, and SDHD). Similarly, we found lineage-specific duplications in genes encoding complex I subunits that interact with quinones (NDUF2 and NDUF7). The phylogenetic analysis of ETC subunits revealed a complex history with independent evolutionary events involving gene duplications and losses. Our results indicated that there is not a common evolutionary event related to ETC subunit genes linked to RQ. The free-living nematode Caenorhabditis elegans uses RQ and has two genes encoding SDHA (sdha-1 and sdha-2) and two genes encoding NDUF2 (nduf2-1 and nduf2-2). sdha-1 and nduf2-1 are essential genes and have a similar expression pattern during C. elegans lifecycle. Using knockout strains, we found that sdha-2 and nduf2-2 are not essential, even in hypoxia. Yet, sdha-2 and nduf2-2 expression is increased in the early embryo and in dauer larvae, stages where there is low oxygen tension. Strikingly, sdha-1 and sdha-2 as well as nduf2-1 and nduf2-2 showed inverted expression profiles during the C. elegans life cycle. Finally, we found that sdha-2 and nduf2-2 knockout mutant strain progeny is affected. Our results indicate that different complex I and II subunit gene duplications provide increased fitness to worms.
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Nematode parasites have a profound impact on humankind, infecting nearly one-quarter of the world's population, as well as livestock. There is a pressing need for discovering nematicides due to the spread of resistance to currently used drugs. The free-living nematode Caenorhabditis elegans is a formidable experimentally tractable model organism that offers key advantages in accelerating nematicide discovery. We report the screening of drug-like libraries using an overnight high-throughput C. elegans assay, based on an automated infrared motility reader. As a proof of concept, we screened the "Pathogen Box" library, and identical results to a previous screen using Haemonchus contortus were obtained. We then screened an in-house library containing a diversity of compound families. Most active compounds had a conjugation of an unsaturation with an electronegative atom (N, O, or S) and an aromatic ring. Importantly, we identified symmetric arylidene ketones and aryl hydrazine derivatives as novel nematicides. Furthermore, one of these compounds, (1E,2E)-1,2-bis(thiophen-3-ylmethylene)hydrazine, was active as a nematicide at 25 µm, but innocuous to the vertebrate model zebrafish at 50 µm. Our results identified novel nematicidal scaffolds and illustrate the value of C. elegans in accelerating nematicide discovery using a nonlabor-intensive automated assay that provides a simple overnight readout.
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Searching for prospective vanadium-based agents against Trypanosoma cruzi, the parasite causing Chagas disease, four new [VVO(8HQ-H)(L-2H)] compounds, where 8HQ is 8-hydroxyquinoline and L are tridentate salicylaldehyde semicarbazone derivatives L1-L4, were synthesized and characterized in the solid state and in solution. The compounds were evaluated on T. cruzi epimastigotes (CL Brener) as well as on VERO cells, as mammalian cell model. Compounds showed activity against T. cruzi (IC50 6.2-10.5 µM) of the same order than Nifurtimox and 8HQ, and a four- to sevenfold activity increase with respect to the free semicarbazones. For comparison, [VVO2(L-H)] series was prepared and the new [VVO2(L3-H)] was fully characterized. They showed negligible activity and low selectivity towards the parasite. The inclusion of 8HQ as ligand in [VVO(8HQ-H)(L-2H)] compounds led to good activities and increased selectivity towards the parasite with respect to 8HQ. 51V NMR experiments, performed to get insight into the nature of the active species, suggested partial decomposition of the compounds in solution to [VVO2(L-H)] and 8HQ. Depending on the dose, the compounds act as trypanocide or trypanostatic. A high uptake of vanadium in the parasites (58.51-88.9% depending on dose) and a preferential accumulation in the soluble protein fraction of the parasite was determined. Treated parasites do not seem to show a late apoptotic/necrotic phenotype suggesting a different cell death mechanism. In vivo toxicity study on zebrafish model showed no toxicity up to a 25 µM concentration of [VVO(8HQ-H)(L1-2H)]. These compounds could be considered prospective anti-T. cruzi agents that deserve further research.
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Complexos de Coordenação/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Vanádio/química , Animais , Apoptose/efeitos dos fármacos , Chlorocebus aethiops , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Complexos de Coordenação/toxicidade , Interações Hidrofóbicas e Hidrofílicas , Estrutura Molecular , Testes de Sensibilidade Parasitária , Tripanossomicidas/síntese química , Tripanossomicidas/química , Tripanossomicidas/toxicidade , Células Vero , Peixe-ZebraRESUMO
The maintenance of thiol-redox homeostasis is vital to the survival of living organisms. Sulfur-based low-molecular weight compounds and proteins synthesized by cells provide efficient and specific ways to counteract oxidative stress and regulate cellular processes. For these tasks, most organisms share the glutathione and thioredoxin NADPH-dependent redox systems. However, in certain lineages, evolution has taken different paths that led to the emergence of novel cysteine-based low-molecular weight redox cofactors, around which new redox systems evolved. These include the sugar-based cysteinyl derivatives mycothiol and bacillithiol, and ergothioneine (EGT), which are present in different phyla from bacteria. Within Eukarya, some fungi contain EGT, whereas trypanothione is unique to species from the Euglenozoa family. This Forum compiles the state-of-the-art knowledge about these noncanonical redox systems of pathogenic organisms. The functions in physiology and pathogenicity, as well as structural and biochemical specializations that these system components evolved, are thoroughly discussed. Antioxid. Redox Signal. 28, 407-409.
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Bactérias/metabolismo , Estresse Oxidativo , Compostos de Sulfidrila/metabolismo , Tiorredoxinas/metabolismo , Cisteína/análogos & derivados , Cisteína/metabolismo , Ergotioneína/metabolismo , Glucosamina/análogos & derivados , Glucosamina/metabolismo , Glutationa/metabolismo , Glicopeptídeos/metabolismo , Homeostase/genética , Inositol/metabolismo , OxirreduçãoRESUMO
The free-living nematode Caenorhabditis elegans is the simplest animal model organism to work with. Substantial knowledge and tools have accumulated over 50 years of C. elegans research. The use of C. elegans relating to parasitic nematodes from a basic biology standpoint or an applied perspective has increased in recent years. The wealth of information gained on the model organism, the use of the powerful approaches and technologies that have advanced C. elegans research to parasitic nematodes and the enormous success of the omics fields have contributed to bridge the divide between C. elegans and parasite nematode researchers. We review key fields, such as genomics, drug discovery and genetics, where C. elegans and nematode parasite research have convened. We advocate the use of C. elegans as a model to study helminth metabolism, a neglected area ready to advance. How emerging technologies being used in C. elegans can pave the way for parasitic nematode research is discussed.
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Caenorhabditis elegans/genética , Descoberta de Drogas , Genômica , Animais , Genoma Helmíntico , Humanos , Doenças Parasitárias/parasitologia , Parasitologia/métodos , PesquisaRESUMO
SIGNIFICANCE: Major pathogenic enterobacteria and protozoan parasites from the phylum Euglenozoa, such as trypanosomatids, are endowed with glutathione (GSH)-spermidine (Sp) derivatives that play important roles in signaling and metal and thiol-redox homeostasis. For some Euglenozoa lineages, the GSH-Sp conjugates represent the main redox cosubstrates around which entire new redox systems have evolved. Several proteins underwent molecular adaptations to synthesize and utilize the new polyamine-based thiols. Recent Advances: The genomes of closely related organisms have recently been sequenced, which allows mining and analysis of gene sequences that belong to these peculiar redox systems. Similarly, the three-dimensional structures of several of these proteins have been solved, which allows for comparison with their counterparts in classical redox systems that rely on GSH/glutaredoxin and thioredoxin. CRITICAL ISSUES: The evolutionary and structural aspects related to the emergence and use of GSH-Sp conjugates in Euglenozoa are reviewed focusing on unique structural specializations that proteins developed to use N1,N8-bisglutathionylspermidine (trypanothione) as redox cosubstrate. An updated overview on the biochemical and biological significance of the major enzymatic activities is also provided. FUTURE DIRECTIONS: A thiol-redox system strictly dependent on trypanothione is a feature unique to trypanosomatids. The physicochemical properties of the polyamine-GSH conjugates were a major driving force for structural adaptation of proteins that use these thiols as ligand and redox cofactor. In fact, the structural differences of indispensable components of this system can be exploited toward selective drug development. Future research should clarify whether additional cellular processes are regulated by the trypanothione system. Antioxid. Redox Signal. 28, 463-486.
Assuntos
Glutarredoxinas/genética , Compostos de Sulfidrila/química , Tiorredoxinas/genética , Trypanosomatina/metabolismo , Evolução Molecular , Glutarredoxinas/química , Glutarredoxinas/metabolismo , Oxirredução , Poliaminas/química , Poliaminas/metabolismo , Espermidina/química , Espermidina/metabolismo , Compostos de Sulfidrila/metabolismo , Tiorredoxinas/química , Tiorredoxinas/metabolismo , Trypanosomatina/química , Trypanosomatina/genéticaRESUMO
AIMS: New drugs are needed to treat flatworm infections that cause severe human diseases such as schistosomiasis. The unique flatworm enzyme thioredoxin glutathione reductase (TGR), structurally different from the human enzyme, is a key drug target. Structural studies of the flatworm Echinococcus granulosus TGR, free and complexed with AuI-MPO, a novel gold inhibitor, together with inhibition assays were performed. RESULTS: AuI-MPO is a potent TGR inhibitor that achieves 75% inhibition at a 1:1 TGR:Au ratio and efficiently kills E. granulosus in vitro. The structures revealed salient insights: (i) unique monomer-monomer interactions, (ii) distinct binding sites for thioredoxin and the glutaredoxin (Grx) domain, (iii) a single glutathione disulfide reduction site in the Grx domain, (iv) rotation of the Grx domain toward the Sec-containing redox active site, and (v) a single gold atom bound to Cys519 and Cys573 in the AuI-TGR complex. Structural modeling suggests that these residues are involved in the stabilization of the Sec-containing C-terminus. Consistently, CysâSer mutations in these residues decreased TGR activities. Mass spectroscopy confirmed these cysteines are the primary binding site. INNOVATION: The identification of a primary site for gold binding and the structural model provide a basis for gold compound optimization through scaffold adjustments. CONCLUSIONS: The structural study revealed that TGR functions are achieved not only through a mobile Sec-containing redox center but also by rotation of the Grx domain and distinct binding sites for Grx domain and thioredoxin. The conserved Cys519 and Cys573 residues targeted by gold assist catalysis through stabilization of the Sec-containing redox center. Antioxid. Redox Signal. 27, 1491-1504.