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1.
Sci Rep ; 10(1): 17073, 2020 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-33051517

RESUMO

Ivermectin is a widely used antiparasitic drug with known efficacy against several single-strain RNA viruses. Recent data shows significant reduction of SARS-CoV-2 replication in vitro by ivermectin concentrations not achievable with safe doses orally. Inhaled therapy has been used with success for other antiparasitics. An ethanol-based ivermectin formulation was administered once to 14 rats using a nebulizer capable of delivering particles with alveolar deposition. Rats were randomly assigned into three target dosing groups, lower dose (80-90 mg/kg), higher dose (110-140 mg/kg) or ethanol vehicle only. A toxicology profile including behavioral and weight monitoring, full blood count, biochemistry, necropsy and histological examination of the lungs was conducted. The pharmacokinetic profile of ivermectin in plasma and lungs was determined in all animals. There were no relevant changes in behavior or body weight. There was a delayed elevation in muscle enzymes compatible with rhabdomyolysis, that was also seen in the control group and has been attributed to the ethanol dose which was up to 11 g/kg in some animals. There were no histological anomalies in the lungs of any rat. Male animals received a higher ivermectin dose adjusted by adipose weight and reached higher plasma concentrations than females in the same dosing group (mean Cmax 86.2 ng/ml vs. 26.2 ng/ml in the lower dose group and 152 ng/ml vs. 51.8 ng/ml in the higher dose group). All subjects had detectable ivermectin concentrations in the lungs at seven days post intervention, up to 524.3 ng/g for high-dose male and 27.3 ng/g for low-dose females. nebulized ivermectin can reach pharmacodynamic concentrations in the lung tissue of rats, additional experiments are required to assess the safety of this formulation in larger animals.


Assuntos
Antiparasitários/uso terapêutico , Infecções por Coronavirus/tratamento farmacológico , Ivermectina/uso terapêutico , Pneumonia Viral/tratamento farmacológico , Administração por Inalação , Animais , Antiparasitários/farmacocinética , Antiparasitários/farmacologia , Comportamento Animal/efeitos dos fármacos , Infecções por Coronavirus/patologia , Relação Dose-Resposta a Droga , Feminino , Meia-Vida , Ivermectina/farmacocinética , Ivermectina/farmacologia , Pulmão/metabolismo , Pulmão/patologia , Masculino , Necrose , Pandemias , Pneumonia Viral/patologia , Estudo de Prova de Conceito , Ratos , Ratos Sprague-Dawley , Transtornos Respiratórios/tratamento farmacológico , Transtornos Respiratórios/patologia
2.
Rev Bras Parasitol Vet ; 29(3): e005220, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32935769

RESUMO

The essential oil of the Melaleuca alternifolia (Maiden & Betche) (tea tree oil) has been effective in previous studies, in the treatment of infestation by Demodex mites in humans. The present study aimed at evaluating the in vitro acaricidal effect of this herbal medicine on Demodex canis. For the parasitological examination, samples were collected from a dog's skin and examined using optical microscopy. Only samples with intact mites and with evident movement of chelicerae and tarsi were selected. Twenty-one samples were tested with the oil, in seven different concentrations: 100%; 50%; 25%; 12.5%; 6.25%; 5.0% and 3.13%. Three samples were tested with the positive control amitraz, and three with the negative control neutral shampoo. The interval between the time the solution was added and the moment the movement of the last mite ceased defined the survival time in the sample. By comparing the times at different concentrations and controls, the results showed that the higher the concentration of the oil, the more quickly its lethal effect occurred, and that the survival times in the controls were longer than in the different concentrations of melaleuca oil.


Assuntos
Ácaros , Óleo de Melaleuca , Animais , Antiparasitários/farmacologia , Cães , Ácaros/efeitos dos fármacos , Óleos Voláteis , Óleo de Melaleuca/farmacologia
3.
Mikrobiyol Bul ; 54(3): 479-489, 2020 Jul.
Artigo em Turco | MEDLINE | ID: mdl-32755522

RESUMO

This study was aimed to investigate the anti-leishmanial effects of bee products (honey and propolis) by using the causative agent of cutaneous leishmaniasis Leishmania tropica promastigotes, in in vitro culture. In vitro anti-leishmanial efficacy of honey (pine, flower and chestnut) and propolis used in the study were evaluated using the microdilution method. Honey, which is a bee product, was dissolved with RPMI medium containing fetal calf serum (FCS) and diluted in the same medium, and serial dilutions were prepared in concentrations between 62.5-1000 mg/ml. Propolis, on the other hand, was dissolved with ethyl alcohol and only 2.5 µl was used from all these concentrations since the alcohol content was more than 50% in these concentrations prepared and we thought that this rate would negatively effect the parasite development. Then, RPMI containing FCS was diluted in the medium and serial dilutions were prepared at concentrations between 50-800 µg/ml. To the dilutions prepared, the promastigot suspension was added so that their final concentrations in the wells were 1 x 106 promastigot/ml and then the medium was incubated for 24 and 48 hours in 26°C. After the incubation, promastigotes were determined microscopically for morphology, mobility and live parasite density, and cell viability was determined by MTS method and 50% inhibitor concentrations (IC50) were compared with control groups. Anti-leishmanial activity of propolis (50, 100, 200, 400 and 800 µg/ml) and honey (62.5, 125, 250, 500 and 1000 mg/ml) on promastigotes was evaluated in vitro. In microscopic examinations, pine honey showed anti-leishmanial activity starting from 62.5 mg/ml, flower honey 250 mg/ml, and chestnut honey 125 mg/ml, and pine honey was more effective on promastigotes (p< 0.05), and propolis was effective from 100 µg/ml concentration. It has been determined that very low concentrations of propolis caused changes in the morphological structure of the parasites and were more effective than the other bee products. The prevention of cell proliferation and decreasing of the IC50 values according with the time of pine honey (IC50= 109.28 mg/ml), flower honey (IC50= 248.07 mg/ml), chestnut honey (IC50= 147.65 mg/ml) and propolis (IC50= 82.98 µg/ml) applied on L.tropica promastigot cell culture was determined by MTS method. In this study, it was found that various concentrations of pine, flower, chestnut honey and propolis showed anti-leishmanial activity on L. tropica promastigotes. It has been observed that pine honey is more effective on promastigotes after 48 hours of incubation period, and propolis is more effective in both morphology and cell inhibition of the parasites even at very low concentrations. It is believed that these data can be used as an alternative treatment method against cutaneous leishmaniasis infections and further studies are required.


Assuntos
Mel , Leishmania tropica , Própole , Animais , Antiparasitários/farmacologia , Abelhas/química , Sobrevivência Celular/efeitos dos fármacos , Leishmania tropica/efeitos dos fármacos , Leishmaniose Cutânea/parasitologia , Estágios do Ciclo de Vida/efeitos dos fármacos , Própole/farmacologia
4.
J Virol ; 94(18)2020 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-32641484

RESUMO

Human adenoviruses (HAdV) are ubiquitous within the human population and comprise a significant burden of respiratory illnesses worldwide. Pediatric and immunocompromised individuals are at particular risk for developing severe disease; however, no approved antiviral therapies specific to HAdV exist. Ivermectin is an FDA-approved broad-spectrum antiparasitic drug that also exhibits antiviral properties against a diverse range of viruses. Its proposed function is inhibiting the classical protein nuclear import pathway mediated by importin-α (Imp-α) and -ß1 (Imp-ß1). Many viruses, including HAdV, rely on this host pathway for transport of viral proteins across the nuclear envelope. In this study, we show that ivermectin inhibits HAdV-C5 early gene transcription, early and late protein expression, genome replication, and production of infectious viral progeny. Similarly, ivermectin inhibits genome replication of HAdV-B3, a clinically important pathogen responsible for numerous recent outbreaks. Mechanistically, we show that ivermectin disrupts binding of the viral E1A protein to Imp-α without affecting the interaction between Imp-α and Imp-ß1. Our results further extend ivermectin's broad antiviral activity and provide a mechanistic underpinning for its mode of action as an inhibitor of cellular Imp-α/ß1-mediated nuclear import.IMPORTANCE Human adenoviruses (HAdVs) represent a ubiquitous and clinically important pathogen without an effective antiviral treatment. HAdV infections typically cause mild symptoms; however, individuals such as children, those with underlying conditions, and those with compromised immune systems can develop severe disseminated disease. Our results demonstrate that ivermectin, an FDA-approved antiparasitic agent, is effective at inhibiting replication of several HAdV types in vitro This is in agreement with the growing body of literature suggesting ivermectin has broad antiviral activity. This study expands our mechanistic knowledge of ivermectin by showing that ivermectin targets the ability of importin-α (Imp-α) to recognize nuclear localization sequences, without effecting the Imp-α/ß1 interaction. These data also exemplify the applicability of targeting host factors upon which viruses rely as a viable antiviral strategy.


Assuntos
Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Adenovírus Humanos/efeitos dos fármacos , Antiparasitários/farmacologia , Ivermectina/farmacologia , Replicação Viral/efeitos dos fármacos , alfa Carioferinas/genética , beta Carioferinas/genética , Células A549 , Transporte Ativo do Núcleo Celular/genética , Adenovírus Humanos/genética , Adenovírus Humanos/metabolismo , Adenovírus Humanos/patogenicidade , Linhagem Celular Tumoral , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Núcleo Celular/virologia , Citosol/efeitos dos fármacos , Citosol/metabolismo , Citosol/virologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/virologia , Regulação da Expressão Gênica , Células HEK293 , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Interações Hospedeiro-Patógeno/genética , Humanos , Transdução de Sinais , Proteínas Virais/antagonistas & inibidores , Proteínas Virais/genética , Proteínas Virais/metabolismo , alfa Carioferinas/antagonistas & inibidores , alfa Carioferinas/metabolismo , beta Carioferinas/metabolismo
5.
An Acad Bras Cienc ; 92(2): e20200466, 2020.
Artigo em Inglês | MEDLINE | ID: covidwho-608501

RESUMO

COVID-19 emerged in December 2019 in China, and since then, has disrupted global public health and changed economic paradigms. In dealing with the new Coronavirus, SARS-CoV-2, the world has not faced such extreme global fragility since the "Spanish flu" pandemic in 1918. Researchers globally are dedicating efforts to the search for an effective treatment for COVID-19. Drugs already used in a clinical setting for other pathologies have been tested as a new therapeutic approach against SARS-CoV-2, setting off a frenzy over the preliminary data of different studies. This work aims to compile and discuss the data published thus far. Despite the potential effects of some antivirals and antiparasitic against COVID-19, clinical studies must confirm real effectiveness. However, non-pharmacological approaches have proven to be the most efficient strategy to date.


Assuntos
Antibacterianos/administração & dosagem , Antiparasitários/administração & dosagem , Antivirais/administração & dosagem , Betacoronavirus/efeitos dos fármacos , Infecções por Coronavirus/tratamento farmacológico , Macrolídeos/administração & dosagem , Pneumonia Viral/tratamento farmacológico , Inibidores de Serino Proteinase/administração & dosagem , Antibacterianos/química , Antibacterianos/farmacologia , Antiparasitários/química , Antiparasitários/farmacologia , Antivirais/química , Antivirais/farmacologia , Humanos , Macrolídeos/química , Macrolídeos/farmacologia , Pandemias , Inibidores de Serino Proteinase/química , Inibidores de Serino Proteinase/farmacologia
6.
Chemosphere ; 259: 127448, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32593828

RESUMO

Ivermectin (IVM), a broad-spectrum antiparasitic drug, is widely used in agriculture and animal husbandry. Due to widespread use and little metabolism in animals, the toxicity of IVM has received increasing attention. The accumulation of IVM in animal tissues and the excretion of urine and feces in the environment is the major source of potential toxicity. Human consumption of meat or milk contaminated with livestock can result in exposure to high levels of IVM exposure. The aim of this study was to reveal the cytotoxic mechanism of IVM in model cell HeLa in vitro, in order to provide a theoretical basis for the safe and rational use of IVM. Here we observed the γH2AX and 8-oxodG foci to detect the DNA damage in HeLa cells. As expected, we found that IVM can induce oxidative double-stranded damage in HeLa cells, indicating that IVM has potential genotoxicity to human health. In addition, we observed the formation of LC3-B in HeLa cells, the accumulation of Beclin1, the degradation of p62 and the activation of the AMPK/mTOR signal transduction pathway. This suggests that IVM confers cytotoxicity through autophagy mediated by the AMPK/mTOR signaling pathway. We conclude that IVM produces genotoxicity and cytotoxicity by inducing DNA damage and AMPK/mTOR-mediated autophagy, thereby posing a potential risk to human health.


Assuntos
Inseticidas/toxicidade , Ivermectina/toxicidade , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Antiparasitários/farmacologia , Autofagia/efeitos dos fármacos , Proteína Beclina-1/metabolismo , Dano ao DNA/efeitos dos fármacos , Células HeLa , Humanos , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo
7.
An Acad Bras Cienc ; 92(2): e20200466, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32556054

RESUMO

COVID-19 emerged in December 2019 in China, and since then, has disrupted global public health and changed economic paradigms. In dealing with the new Coronavirus, SARS-CoV-2, the world has not faced such extreme global fragility since the "Spanish flu" pandemic in 1918. Researchers globally are dedicating efforts to the search for an effective treatment for COVID-19. Drugs already used in a clinical setting for other pathologies have been tested as a new therapeutic approach against SARS-CoV-2, setting off a frenzy over the preliminary data of different studies. This work aims to compile and discuss the data published thus far. Despite the potential effects of some antivirals and antiparasitic against COVID-19, clinical studies must confirm real effectiveness. However, non-pharmacological approaches have proven to be the most efficient strategy to date.


Assuntos
Antibacterianos/administração & dosagem , Antiparasitários/administração & dosagem , Antivirais/administração & dosagem , Betacoronavirus/efeitos dos fármacos , Infecções por Coronavirus/tratamento farmacológico , Macrolídeos/administração & dosagem , Pneumonia Viral/tratamento farmacológico , Inibidores de Serino Proteinase/administração & dosagem , Antibacterianos/química , Antibacterianos/farmacologia , Antiparasitários/química , Antiparasitários/farmacologia , Antivirais/química , Antivirais/farmacologia , Humanos , Macrolídeos/química , Macrolídeos/farmacologia , Pandemias , Inibidores de Serino Proteinase/química , Inibidores de Serino Proteinase/farmacologia
8.
Parasitol Res ; 119(7): 2025-2037, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32504119

RESUMO

Leishmaniasis is a neglected tropical disease with no effective vaccines to date. Globally, it affects around 14 million people living in undeveloped and developing countries. Leishmania, which is the causative eukaryotic organism, possesses unique enzymes and pathways that deviates from its mammalian hosts. The control strategy against leishmaniasis currently depends on chemotherapeutic methods. But these chemotherapeutic therapies possess several side effects, and therefore, the identification of potential drug targets has become very crucial. Identification of suitable drug targets is necessary to design specific inhibitors that can target and control the parasite. These unique enzymes can be used as possible drug targets after biochemical characterization and understanding the role of these enzymes. In this review, the authors discuss various metabolic pathways that are essential for the survival of the parasite and can be exploited as potential drug targets against leishmaniasis.


Assuntos
Antiparasitários , Leishmania/metabolismo , Leishmaniose/tratamento farmacológico , Redes e Vias Metabólicas/efeitos dos fármacos , Terapia de Alvo Molecular , Animais , Antiparasitários/farmacologia , Antiparasitários/uso terapêutico , Sistemas de Liberação de Medicamentos , Humanos , Leishmania/efeitos dos fármacos
9.
J Vis Exp ; (158)2020 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-32420988

RESUMO

Toxoplasma gondii is a protozoan pathogen that widely affects the human population. The current antibiotics used for treating clinical toxoplasmosis are limited. In addition, they exhibit adverse side effects in certain groups of people. Therefore, discovery of novel therapeutics for clinical toxoplasmosis is imperative. The first step of novel antibiotic development is to identify chemical compounds showing high efficacy in inhibition of parasite growth using a high throughput screening strategy. As an obligate intracellular pathogen, Toxoplasma can only replicate within host cells, which prohibits the use of optical absorbance measurements as a quick indicator of growth. Presented here is a detailed protocol for a luciferase-based growth assay. As an example, this method is used to calculate the doubling time of wild-type Toxoplasma parasites and measure the efficacy of morpholinurea-leucyl-homophenyl-vinyl sulfone phenyl (LHVS, a cysteine protease-targeting compound) regarding inhibition of parasite intracellular growth. Also described, is a CRISPR-Cas9-based gene deletion protocol in Toxoplasma using 50 bp homologous regions for homology-dependent recombination (HDR). By quantifying the inhibition efficacies of LHVS in wild-type and TgCPL (Toxoplasma cathepsin L-like protease)-deficient parasites, it is shown that LHVS inhibits wild-type parasite growth more efficiently than Δcpl growth, suggesting that TgCPL is a target that LHVS binds to in Toxoplasma. The high sensitivity and easy operation of this luciferase-based growth assay make it suitable for monitoring Toxoplasma proliferation and evaluating drug efficacy in a high throughput manner.


Assuntos
Bioensaio , Toxoplasma/crescimento & desenvolvimento , Animais , Antiparasitários/farmacologia , Luciferases/metabolismo , Proteínas de Protozoários/genética , Toxoplasma/efeitos dos fármacos , Toxoplasma/genética , Toxoplasmose
10.
Parasitol Res ; 119(6): 1925-1941, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32279093

RESUMO

Toxoplasmosis is a common parasitic disease caused by Toxoplasma gondii. Limitations of available treatments motivate the search for better therapies for toxoplasmosis. In this study, we synthesized a series of new imidazole derivatives: bis-imidazoles (compounds 1-8), phenyl-substituted 1H-imidazoles (compounds 9-19), and thiopene-imidazoles (compounds 20-26). All these compounds were assessed for in vitro potential to restrict the growth of T. gondii. To explore the structure-activity relationships, molecular analyses and bioactivity prediction studies were performed using a standard molecular model. The in vitro results, in combination with the predictive model, revealed that the imidazole derivatives have excellent selectivity activity against T. gondii versus the host cells. Of the 26 compounds screened, five imidazole derivatives (compounds 10, 11, 18, 20, and 21) shared a specific structural moiety and exhibited significantly high selectivity (> 1176 to > 27,666) towards the parasite versus the host cells. These imidazole derivatives are potential candidates for further studies. We show evidence that supports the antiparasitic action of the imidazole derivatives. The findings are promising in that they reinforce the prospects of imidazole derivatives as alternative and effective antiparasitic therapy as well as providing evidence for a probable biological mechanism.


Assuntos
Antiparasitários/química , Antiparasitários/farmacologia , Imidazóis/química , Imidazóis/farmacologia , Toxoplasma/efeitos dos fármacos , Animais , Células Cultivadas , Humanos , Imidazóis/síntese química , Modelos Moleculares , Relação Estrutura-Atividade , Toxoplasmose/parasitologia
11.
Poult Sci ; 99(4): 1978-1982, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32241479

RESUMO

Histomoniasis, caused by the protozoan parasite Histomonas meleagridis, is a disease to which turkeys are especially susceptible. Currently, no chemoprophylaxis compounds are available to mitigate this disease. Boric acid (BA) exhibits antifungal, antiseptic, and antiviral properties and has been used in the treatment of yeast infections. Based on these characteristics, an experiment was conducted to evaluate whether BA might be an efficacious prophylaxis against challenge with wild-type H. meleagridis (WTH). On day-of-hatch, poults were randomly assigned to either a basal control diet or a BA diet (basal diet + 0.2% BA). Groups consisted of a nonchallenged control (NC; basal diet), 0.2% BA + challenge (BA; 0.2% BA diet), and a positive-challenged control (PC; basal diet). On day 21, challenged groups were intracloacally inoculated with 2 × 105 WTH cells/turkey, and lesions were evaluated on day 14 postchallenge. Individual body weights were recorded on day 0, 21, and 35 to calculate the prechallenge and postchallenge body weight gain (BWG). The BA group resulted in lower prechallenge day 0 to day 21 BWG (P = 0.0001) than the NC group. Postchallenge day 21 to day 35, BWG was also lower (P = 0.0503) in the BA group than the PC group. No differences between the BA and PC groups were detected for mortalities associated with histomoniasis. Moreover, liver and cecal lesions were not statistically different between the BA and PC groups. Taken together, these data suggest that BA was not efficacious in the prevention or reduction of histomoniasis disease severity when provided at 0.2% dietary concentration under these experimental conditions.


Assuntos
Antiparasitários/farmacologia , Ácidos Bóricos/farmacologia , Doenças das Aves Domésticas/prevenção & controle , Infecções Protozoárias em Animais/prevenção & controle , Trichomonadida/efeitos dos fármacos , Perus , Animais , Quimioprevenção/veterinária , Feminino , Doenças das Aves Domésticas/parasitologia , Infecções Protozoárias em Animais/parasitologia
12.
J Fish Dis ; 43(6): 665-672, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32291787

RESUMO

Gill parasitic infections challenge farming of rainbow trout (Oncorhynchus mykiss, Walbaum) in freshwater facilities. Apart from flagellates (Ichthyobodo, (Pinto) and ciliates (Ichthyophthirius (Fouquet), Ambiphrya (Raabe), Apiosoma (Blanchard), Trichodinella (Sramek-Husek) and Trichodina (Ehrenberg)), we have shown that amoebae are prevalent in Danish trout farms. Gills were isolated from farmed rainbow trout in six fish farms (conventional and organic earth pond and recirculated systems) and placed on non-nutrient agar (NNA) moistened with modified Neff's amoeba saline (AS) (15°C). Gill amoebae from all examined fish colonized the agar and were identified based on morphological criteria showing species within the genera Trinema (Dujardin) (family Trinematidae), Vannella (Bovee) (family Vannellidae). In addition, hartmannellid amoebae were recorded. We established a monoculture of Vannella sp., confirmed the genus identity by PCR and sequencing and performed an in vitro determination of antiparasitic effects (dose-response studies) of various compounds including sodium chloride (NaCl), hydrogen peroxide, peracetic acid, formalin, aqueous garlic and oregano extracts and a Pseudomonas H6 surfactant. All amoebae were killed in concentrations of 16.90 mg/ml (garlic), 17.90 mg/ml (oregano), NaCl (7.5 mg/ml), hydrogen peroxide (100 µg/ml), peracetic acid (0.03 µg/ml), formaldehyde (25 µg/ml) and the Pseudomonas H6 surfactant (250 µg/ml).


Assuntos
Amebíase/veterinária , Antiparasitários/farmacologia , Oncorhynchus mykiss , Tubulinos/efeitos dos fármacos , Amebíase/tratamento farmacológico , Amebíase/parasitologia , Animais , Relação Dose-Resposta a Droga , Doenças dos Peixes/tratamento farmacológico , Doenças dos Peixes/parasitologia , Água Doce , Brânquias/parasitologia , Técnicas In Vitro
13.
Artigo em Inglês | MEDLINE | ID: mdl-32234669

RESUMO

Giardia duodenalis, the most prevalent human intestinal parasite causes the disease, giardiasis. On an annual basis G. duodenalis infects ~1 billion people, of which ~280 million develop symptomatic disease. Giardiasis can be severe and chronic, causing malnutrition, stunted growth and poor cognitive development in children. Current treatment options rely on drugs with declining efficacy and side-effects. To improve the health and well-being of millions of people world-wide, new anti-Giardia drugs with different modes of action to currently used drugs are required. The Medicines for Malaria Venture's Pathogen Box, a collection of bio-active compounds specifically chosen to stimulate infectious disease drug discovery, represents an opportunity for the discovery of new anti-Giardia agents. While the anti-Giardia activity of Pathogen Box compounds has been reported, this work failed to identify known anti-Giardia controls within the compound set. It also reported the activity of compounds previously screened and shown to be inactive by others, suggesting data may be inaccurate. Given these concerns the anti-Giardia activity of Pathogen Box compounds was re-assessed in the current study. Data from this work identified thirteen compounds with anti-Giardia IC50 values ≤2 µM. Five of these compounds were reference compounds (marketed drugs with known anti-microbial activity), or analogues of compounds with previously described anti-Giardia activity. However, eight, including MMV676358 and MMV028694, which demonstrated potent sub-µM IC50s against assemblage A, B and metronidazole resistant parasites (0.3 µM and 0.9 µM respectively), may represent new leads for future drug development. Interestingly, only four of these compounds were identified in the previously reported Pathogen Box screen highlighting the importance of assay selection and design when assessing compounds for activity against infectious agents.


Assuntos
Antiparasitários/isolamento & purificação , Antiparasitários/farmacologia , Bioensaio/métodos , Descoberta de Drogas/métodos , Giardia lamblia/efeitos dos fármacos , Giardia/efeitos dos fármacos , Descoberta de Drogas/instrumentação , Giardíase/tratamento farmacológico , Humanos , Concentração Inibidora 50 , Testes de Sensibilidade Parasitária , Prevalência
14.
PLoS Negl Trop Dis ; 14(4): e0008224, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32302296

RESUMO

Giardiasis and other protozoan infections are major worldwide causes of morbidity and mortality, yet development of new antimicrobial agents with improved efficacy and ability to override increasingly common drug resistance remains a major challenge. Antimicrobial drug development typically proceeds by broad functional screens of large chemical libraries or hypothesis-driven exploration of single microbial targets, but both strategies have challenges that have limited the introduction of new antimicrobials. Here, we describe an alternative drug development strategy that identifies a sufficient but manageable number of promising targets, while reducing the risk of pursuing targets of unproven value. The strategy is based on defining and exploiting the incompletely understood adduction targets of 5-nitroimidazoles, which are proven antimicrobials against a wide range of anaerobic protozoan and bacterial pathogens. Comprehensive adductome analysis by modified click chemistry and multi-dimensional proteomics were applied to the model pathogen Giardia lamblia to identify dozens of adducted protein targets common to both 5'-nitroimidazole-sensitive and -resistant cells. The list was highly enriched for known targets in G. lamblia, including arginine deiminase, α-tubulin, carbamate kinase, and heat shock protein 90, demonstrating the utility of the approach. Importantly, over twenty potential novel drug targets were identified. Inhibitors of two representative new targets, NADP-specific glutamate dehydrogenase and peroxiredoxin, were found to have significant antigiardial activity. Furthermore, all the identified targets remained available in resistant cells, since giardicidal activity of the respective inhibitors was not impacted by resistance to 5'-nitroimidazoles. These results demonstrate that the combined use of click chemistry and proteomics has the potential to reveal alternative drug targets for overcoming antimicrobial drug resistance in protozoan parasites.


Assuntos
Antiparasitários/farmacologia , Química Click/métodos , Descoberta de Drogas/métodos , Giardia lamblia/efeitos dos fármacos , Indazóis/farmacologia , Proteínas de Protozoários/metabolismo , Animais , Antiparasitários/síntese química , Antiparasitários/uso terapêutico , Modelos Animais de Doenças , Feminino , Giardíase/tratamento farmacológico , Indazóis/síntese química , Indazóis/uso terapêutico , Intestino Delgado/parasitologia , Masculino , Camundongos Endogâmicos C57BL , Carga Parasitária , Ligação Proteica , Proteômica/métodos
15.
J Immunol ; 204(7): 1869-1880, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32132181

RESUMO

Leishmaniases are neglected tropical diseases. The treatment of leishmaniasis relies exclusively on chemotherapy including amphotericin B (AmB), miltefosine (hexadecylphosphocholine), and pentamidine. Besides the fact that these molecules are harmful for patients, little is known about the impact of such antileishmanial drugs on primary human cells in relation to immune function. The present study demonstrates that all antileishmanial drugs inhibit CD4 and CD8 T cell proliferation at the doses that are not related to increased cell death. Our results highlight that antileishmanial drugs have an impact on monocytes by altering the expression of IL-12 induced by LPS, whereas only AmB induced IL-10 secretion; both cytokines are essential in regulating Th1 cell-mediated immunity. Interestingly, IL-12 and anti-IL-10 Abs improved T cell proliferation inhibited by AmB. Furthermore, our results show that in contrast to hexadecylphosphocholine and pentamidine, AmB induced gene expression of the inflammasome pathway. Thus, AmB induced IL-1ß and IL-18 secretions, which are reduced by specific inhibitors of caspase activation (Q-VD) and NLRP3 activation (MCC950). Our results reveal previously underestimated effects of antileishmanial drugs on primary human cells.


Assuntos
Antiparasitários/farmacologia , Inflamassomos/efeitos dos fármacos , Interleucina-12/metabolismo , Leishmania/genética , Leishmaniose/tratamento farmacológico , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/metabolismo , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Citocinas/metabolismo , Humanos , Inflamassomos/metabolismo , Interleucina-10/metabolismo , Leishmania/metabolismo , Leishmaniose/metabolismo , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Transdução de Sinais/efeitos dos fármacos
16.
Sci Rep ; 10(1): 4495, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32161276

RESUMO

Pythiosis is a harmful disease caused by Pythium insidiosum, an aquatic oomycete. Therapeutic protocols based on antifungal drugs are often ineffective because the cytoplasmic membrane of P. insidiosum does not contain ergosterol. Therefore, the treatment of pythiosis is still challenging, particularly making use of natural products and secondary metabolites from bacteria. In this study, xanthyletin and substances obtained from Pseudomonas stutzeri ST1302 and Klebsiella pneumoniae ST2501 exhibited anti-P. insidiosum activity and, moreover, xanthyletin was non-toxic against human cell lines. The hyphae of P. insidiosum treated with these three substances exhibited lysis holes on a rough surface and release of anamorphic material. Therefore, xanthyletin could be considered a promising alternative agent for treating cutaneous pythiosis in the near future.


Assuntos
Antifúngicos/farmacologia , Antiparasitários/farmacologia , Cumarínicos/farmacologia , Pythium/efeitos dos fármacos , Bactérias/química , Bactérias/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Misturas Complexas , Fibroblastos/efeitos dos fármacos , Humanos , Hifas/efeitos dos fármacos , Hifas/ultraestrutura , Testes de Sensibilidade Microbiana
17.
Parasitol Int ; 76: 102097, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32114085

RESUMO

How human macrophages can control the intracellular infection with Leishmania is not completely understood. IL-15 and IL-32 are cytokines produced by monocytes/macrophages that can induce antimicrobial mechanisms. Here, we evaluated the effects of recombinant human IL-15 (rhIL-15) on primary human macrophage infection and response to L. braziliensis. Priming with rhIL-15 reduced the phagocytosis of L. braziliensis and increased the killing of the parasites in monocyte-derived macrophages from healthy donors. rhIL-15 induced TNFα and IL-32 in uninfected cells. After infection, the high levels of rhIL-15-induced TNFα and IL-32 were maintained. In addition, there was an increase of NO and an inhibition of the parasite-induced IL-10 production. Inhibition of NO reversed the leishmanicidal effects of rhIL-15. Although rhIL-15 did not increase L. braziliensis-induced reactive oxygen intermediates (ROS) production, inhibition of ROS reversed the control of infection induced by rhIL-15. Treatment of the cells with rhIL-32γ increased microbicidal capacity of macrophages in the presence of high levels of vitamin D (25D3), but not in low concentrations of this vitamin. rhIL-15 together with rhIL-32 lead to the highest control of the L. braziliensis infection in high concentrations of vitamin D. In this condition, NO and ROS mediated rhIL-32γ effects on microbicidal activity. The data showed that priming of human macrophages with rhIL-15 or rhIL-32γ results in the control of L. braziliensis infection through induction of NO and ROS. In addition, rhIL-32γ appears to synergize with rhIL-15 for the control of L. braziliensis infection in a vitamin D-dependent manner.


Assuntos
Antiparasitários/metabolismo , Interleucina-15/metabolismo , Interleucinas/metabolismo , Leishmania braziliensis/efeitos dos fármacos , Leishmaniose Cutânea/tratamento farmacológico , Vitamina D/metabolismo , Antiparasitários/farmacologia , Interleucina-15/farmacologia , Interleucinas/farmacologia , Leishmania braziliensis/fisiologia , Proteínas Recombinantes/metabolismo , Transdução de Sinais , Vitamina D/farmacologia
18.
Parasitol Int ; 76: 102093, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32120050

RESUMO

Miamiensis avidus causes scuticociliatosis in cultured olive flounders (Paralichthys olivaceus), leading to economic losses in aquaculture in Korea. Quantitative evaluation of the viability of M. avidus is important to develop an effective vaccine or chemotherapeutic agent against it. We used a colorimetric assay based on the reduction of 2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium (WST-1) to quantify the viability of M. avidus. Using this method, we investigated the effect of protease inhibitors on the viability of M. avidus. The assay showed a clear difference in the optical density (OD) of over 104 ciliates, and the metalloprotease inhibitors 1, 10-phenanthroline and ethylenediaminetetraacetic acid (EDTA) reduced the viability of M. avidus by more than 90% when used at concentration of 5 mM and 100 µM, respectively. However, different morphological changes in the parasite were observed when exposed to these two inhibitors. These results indicate that the WST-1 assay is a simple and reliable method to quantify the viability of M. avidus, and metalloproteases are excellent targets for the development of agents and vaccines to control M. avidus infection.


Assuntos
Antiparasitários/farmacologia , Infecções por Cilióforos/veterinária , Colorimetria/veterinária , Doenças dos Peixes/parasitologia , Oligoimenóforos/efeitos dos fármacos , Inibidores de Proteases/farmacologia , Sais de Tetrazólio/química , Animais , Infecções por Cilióforos/parasitologia , Colorimetria/instrumentação , Viabilidade Microbiana/efeitos dos fármacos , Oligoimenóforos/fisiologia
19.
Chemosphere ; 250: 126271, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32114345

RESUMO

Pesticides and veterinary products that are globally used in farming against pests and parasites are known to impact non-target beneficial organisms. While most studies have tested the lethal and sub-lethal effects of single chemicals, species are exposed to multiple contaminants that might interact and exacerbate the toxic responses of life-history fitness components. Here we experimentally tested an ecotoxicological scenario that is likely to be widespread in nature, with non-target dung communities being exposed both to cattle parasiticides during the larval stage and to agricultural insecticides during their adult life. We assessed the independent and combined consumptive effects of varying ivermectin and spinosad concentration on juvenile life-history and adult reproductive traits of the widespread yellow dung fly (Scathophaga stercoraria; Diptera: Scathophagidae). Larval exposure to ivermectin prolonged development time and reduced egg-to-adult survival, body size, and the magnitude of the male-biased sexual size dimorphism. The consumption by the predatory adult flies of spinosad-contaminated prey showed an additional, independent (from ivermectin) negative effect on female clutch size, and subsequent egg hatching success, but not on the body size and sexual size dimorphism of their surviving offspring. However, there were interactive synergistic effects of both contaminants on offspring emergence and body size. Our results document adverse effects of the combination of different chemicals on fitness components of a dung insect, highlighting transgenerational effects of adult exposure to contaminants for their offspring. These findings suggest that ecotoxicological tests should consider the combination of different contaminants for more accurate eco-assessments.


Assuntos
Ecotoxicologia/métodos , Insetos/efeitos dos fármacos , Praguicidas/farmacologia , Animais , Antiparasitários/farmacologia , Tamanho Corporal/efeitos dos fármacos , Bovinos , Dípteros/efeitos dos fármacos , Combinação de Medicamentos , Interações Medicamentosas , Feminino , Ivermectina/toxicidade , Larva/efeitos dos fármacos , Macrolídeos/toxicidade , Masculino , Praguicidas/análise , Reprodução/efeitos dos fármacos
20.
PLoS Negl Trop Dis ; 14(3): e0008150, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32196500

RESUMO

Parasitic infections are a major source of human suffering, mortality, and economic loss, but drug development for these diseases has been stymied by the significant expense involved in bringing a drug though clinical trials and to market. Identification of single compounds active against multiple parasitic pathogens could improve the economic incentives for drug development as well as simplifying treatment regimens. We recently performed a screen of repurposed compounds against the protozoan parasite Entamoeba histolytica, causative agent of amebic dysentery, and identified four compounds (anisomycin, prodigiosin, obatoclax and nithiamide) with low micromolar potency and drug-like properties. Here, we extend our investigation of these drugs. We assayed the speed of killing of E. histolytica trophozoites and found that all four have more rapid action than the current drug of choice, metronidazole. We further established a multi-institute collaboration to determine whether these compounds may have efficacy against other parasites and opportunistic pathogens. We found that anisomycin, prodigiosin and obatoclax all have broad-spectrum antiparasitic activity in vitro, including activity against schistosomes, T. brucei, and apicomplexan parasites. In several cases, the drugs were found to have significant improvements over existing drugs. For instance, both obatoclax and prodigiosin were more efficacious at inhibiting the juvenile form of Schistosoma than the current standard of care, praziquantel. Additionally, low micromolar potencies were observed against pathogenic free-living amebae (Naegleria fowleri, Balamuthia mandrillaris and Acanthamoeba castellanii), which cause CNS infection and for which there are currently no reliable treatments. These results, combined with the previous human use of three of these drugs (obatoclax, anisomycin and nithiamide), support the idea that these compounds could serve as the basis for the development of broad-spectrum anti-parasitic drugs.


Assuntos
Anisomicina/farmacologia , Antiparasitários/farmacologia , Reposicionamento de Medicamentos , Parasitos/efeitos dos fármacos , Prodigiosina/farmacologia , Pirróis/farmacologia , Animais , Anisomicina/efeitos adversos , Anisomicina/farmacocinética , Antiparasitários/efeitos adversos , Antiparasitários/farmacocinética , Linhagem Celular , Sobrevivência Celular , Fibroblastos/efeitos dos fármacos , Humanos , Camundongos , Testes de Sensibilidade Parasitária , Prodigiosina/efeitos adversos , Prodigiosina/farmacocinética , Pirróis/efeitos adversos , Pirróis/farmacocinética , Ratos
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