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2.
Exp Parasitol ; 218: 108008, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32979343

RESUMO

Acanthamoeba sp. is a free living amoeba that causes severe, painful and fatal infections, viz. Acanthamoeba keratitis and granulomatous amoebic encephalitis among humans. Antimicrobial chemotherapy used against Acanthamoeba is toxic to human cells and show side effects as well. Infections due to Acanthamoeba also pose challenges towards currently used antimicrobial treatment including resistance and transformation of trophozoites to resistant cyst forms that can lead to recurrence of infection. Therapeutic agents targeting central nervous system infections caused by Acanthamoeba should be able to cross blood-brain barrier. Nanoparticles based drug delivery put forth an effective therapeutic method to overcome the limitations of currently used antimicrobial chemotherapy. In recent years, various researchers investigated the effectiveness of nanoparticles conjugated drug and/or naturally occurring plant compounds against both trophozoites and cyst form of Acanthamoeba. In the current review, a reasonable effort has been made to provide a comprehensive overview of various nanoparticles tested for their efficacy against Acanthamoeba. This review summarizes the noteworthy details of research performed to elucidate the effect of nanoparticles conjugated drugs against Acanthamoeba.


Assuntos
Acanthamoeba/efeitos dos fármacos , Amebicidas/administração & dosagem , Nanopartículas/administração & dosagem , Acanthamoeba/crescimento & desenvolvimento , Ceratite por Acanthamoeba/tratamento farmacológico , Ceratite por Acanthamoeba/parasitologia , Amebíase/tratamento farmacológico , Amebíase/mortalidade , Amebíase/parasitologia , Amebicidas/farmacologia , Amebicidas/uso terapêutico , Biguanidas/administração & dosagem , Biguanidas/farmacologia , Biguanidas/uso terapêutico , Infecções Protozoárias do Sistema Nervoso Central/tratamento farmacológico , Infecções Protozoárias do Sistema Nervoso Central/mortalidade , Infecções Protozoárias do Sistema Nervoso Central/parasitologia , Clorexidina/administração & dosagem , Clorexidina/farmacologia , Clorexidina/uso terapêutico , Sistemas de Liberação de Medicamentos , Imunocompetência , Hospedeiro Imunocomprometido , Encefalite Infecciosa/tratamento farmacológico , Encefalite Infecciosa/mortalidade , Encefalite Infecciosa/parasitologia , Nanopartículas/classificação , Nanopartículas/uso terapêutico , Trofozoítos/efeitos dos fármacos
3.
Parasitol Res ; 119(8): 2587-2595, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32524267

RESUMO

Lycorine is an Amaryllidaceae alkaloid that presents anti-Trichomonas vaginalis activity. T. vaginalis causes trichomoniasis, the most common non-viral sexually transmitted infection. The modulation of T. vaginalis purinergic signaling through the ectonucleotidases, nucleoside triphosphate diphosphohydrolase (NTPDase), and ecto-5'-nucleotidase represents new targets for combating the parasite. With this knowledge, the aim of this study was to investigate whether NTPDase and ecto-5'-nucleotidase inhibition by lycorine could lead to extracellular ATP accumulation. Moreover, the lycorine effect on the reactive oxygen species (ROS) production by neutrophils and parasites was evaluated as well as the alkaloid toxicity. The metabolism of purines was assessed by HPLC. ROS production was measured by flow cytometry. Cytotoxicity against epithelial vaginal cells and fibroblasts was tested, as well as the hemolytic effect of lycorine and its in vivo toxicity in Galleria mellonella larvae. Our findings showed that lycorine caused ATP accumulation due to NTPDase inhibition. The alkaloid did not affect the ROS production by T. vaginalis; however, it increased ROS levels in neutrophils incubated with lycorine-treated trophozoites. Lycorine was cytotoxic against vaginal epithelial cells and fibroblasts; conversely, it was not hemolytic neither exhibited toxicity against the in vivo model of G. mellonella larvae. Overall, besides having anti-T. vaginalis activity, lycorine modulates ectonucleotidases and stimulates neutrophils to secrete ROS. This mechanism of action exerted by the alkaloid could enhance the susceptibility of T. vaginalis to host immune cell, contributing to protozoan clearance.


Assuntos
Alcaloides de Amaryllidaceae/farmacologia , Amaryllidaceae/química , Antiprotozoários/farmacologia , Neutrófilos/metabolismo , Nucleosídeo-Trifosfatase/antagonistas & inibidores , Fenantridinas/farmacologia , Extratos Vegetais/farmacologia , Proteínas de Protozoários/antagonistas & inibidores , Tricomoníase/metabolismo , Trichomonas vaginalis/enzimologia , 5'-Nucleotidase/antagonistas & inibidores , 5'-Nucleotidase/metabolismo , Humanos , Neutrófilos/efeitos dos fármacos , Nucleosídeo-Trifosfatase/metabolismo , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Tricomoníase/parasitologia , Trichomonas vaginalis/efeitos dos fármacos , Trichomonas vaginalis/crescimento & desenvolvimento , Trichomonas vaginalis/metabolismo , Trofozoítos/efeitos dos fármacos , Trofozoítos/enzimologia , Trofozoítos/crescimento & desenvolvimento , Trofozoítos/metabolismo
4.
Exp Parasitol ; 215: 107915, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32461112

RESUMO

Acanthamoeba castellanii is an opportunistic protozoan responsible for serious human infections including Acanthamoeba keratitis and granulomatous amoebic encephalitis. Despite advances in antimicrobial therapy and supportive care, infections due to Acanthamoeba are a major public concern. Current methods of treatment are not fully effective against both the trophozoite and cyst forms of A. castellanii and are often associated with severe adverse effects, host cell cytotoxicity and recurrence of infection. Therefore, there is an urgent need to develop new therapeutic approaches for the treatment and management of Acanthamoebic infections. Repurposing of clinically approved drugs is a viable avenue for exploration and is particularly useful for neglected and rare diseases where there is limited interest by pharmaceutical companies. Nanotechnology-based drug delivery systems offer promising approaches in the biomedical field, particularly in diagnosis and drug delivery. Herein, we conjugated an antihyperglycemic drug, metformin with silver nanoparticles and assessed its anti-acanthamoebic properties. Characterization by ultraviolet-visible spectrophotometry and atomic force microscopy showed successful formation of metformin-coated silver nanoparticles. Amoebicidal and amoebistatic assays revealed that metformin-coated silver nanoparticles reduced the viability and inhibited the growth of A. castellanii significantly more than metformin and silver nanoparticles alone at both 5 and 10 µM after 24 h incubation. Metformin-coated silver nanoparticles also blocked encystation and inhibited the excystation in Acanthamoeba after 72 h incubation. Overall, the conjugation of metformin with silver nanoparticles was found to enhance its antiamoebic effects against A. castellanii. Furthermore, the pretreatment of A. castellanii with metformin and metformin-coated silver nanoparticles for 2 h also reduced the amoebae-mediated host cell cytotoxicity after 24 h incubation from 73% to 10% at 10 µM, indicating that the drug-conjugated silver nanoparticles confer protection to human cells. These findings suggest that metformin-coated silver nanoparticles hold promise in the improved treatment and management of Acanthamoeba infections.


Assuntos
Acanthamoeba castellanii/efeitos dos fármacos , Metformina/administração & dosagem , Ceratite por Acanthamoeba/tratamento farmacológico , Ceratite por Acanthamoeba/parasitologia , Anti-Infecciosos Locais/farmacologia , Infecções Protozoárias do Sistema Nervoso Central/tratamento farmacológico , Infecções Protozoárias do Sistema Nervoso Central/parasitologia , Clorexidina/farmacologia , Células HeLa , Humanos , Encefalite Infecciosa/tratamento farmacológico , Encefalite Infecciosa/parasitologia , Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/uso terapêutico , Metformina/farmacologia , Metformina/uso terapêutico , Microscopia de Força Atômica , Encistamento de Parasitas/efeitos dos fármacos , Prata , Espectrofotometria Ultravioleta , Trofozoítos/efeitos dos fármacos
5.
BMC Complement Med Ther ; 20(1): 63, 2020 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32111225

RESUMO

BACKGROUND: Giardia duodenalis causes giardiasis in humans, particularly in developing countries. Despite the availability of treatments, resistance to some of the commercial anti-Giardia drugs has been reported in addition to their harmful side effects. Therefore, novel treatments for giardiasis are required. In this study, we aimed to assess the in vitro activity of crude extracts of Ageratum conyzoides against G. duodenalis trophozoites. METHODS: Plants were classified into three groups based on their flower colors: white (W), purple (P), and white-purple (W-P). Plants were separately cut into leaf (L) and flower (F) parts. Changes in internal organelle morphology of trophozoites following exposure to crude extracts were assessed using transmission electron microscopy (TEM). In subsequent experiments, efficacy of the most active essential oils from crude extracts [half maximal inhibitory concentrations (IC50) ≤ 100 µg/mL] against G. duodenalis trophozoites was tested. In vitro anti-Giardia assays using essential oils were performed in the same way as those performed using crude extracts. RESULTS: LW-P and FP extracts showed high activity (IC50 ≤ 100 µg/mL) against G. duodenalis trophozoites, with IC50 ± SD values of 45.67 ± 0.51 and 96.00 ± 0.46 µg/mL, respectively. In subsequent experiments, IC50 ± SD values of LW-P and FP essential oils were 35.00 ± 0.50 and 89.33 ± 0.41 µg/mL, respectively. TEM revealed the degeneration of flagella and ventral discs of G. duodenalis trophozoites following exposure to crude extracts. CONCLUSION: Crude LW-P and FP extracts of A. conyzoides showed the highest activity against G. duodenalis. Exposure to crude extract induced changes in the flagella and ventral discs of G. duodenalis trophozoites, which play important roles in attachment to the surface of mucosal cells. Our results suggest that the tested extracts warrant further research in terms of their efficacy and safety as giardiasis treatment.


Assuntos
Ageratum/química , Giardia lamblia/efeitos dos fármacos , Giardíase/tratamento farmacológico , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Trofozoítos/efeitos dos fármacos , Cromatografia Gasosa , Giardia lamblia/ultraestrutura , Espectrometria de Massas , Microscopia Eletrônica de Transmissão , Tailândia , Trofozoítos/ultraestrutura
6.
J Fr Ophtalmol ; 43(4): 330-333, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32151474

RESUMO

Acanthamoeba keratitis due to a genus of free-living amoebae is a severe corneal infection. Treatment of this disease is based on the combined use of antiseptics and other drugs, including azoles. We tested isavuconazole, the latest marketed azole, in vitro, against A. castellanii, A. lenticulata and A. hatchetti. Our results show that isavuconazole presents slight amoebistatic activity against A. castellanii trophozoites but no cysticidal activity. Isavuconazole could be used only in association for management of AK due to A. castellanii.


Assuntos
Ceratite por Acanthamoeba/parasitologia , Acanthamoeba/efeitos dos fármacos , Nitrilos/farmacologia , Piridinas/farmacologia , Triazóis/farmacologia , Acanthamoeba/classificação , Acanthamoeba/crescimento & desenvolvimento , Acanthamoeba/fisiologia , Ceratite por Acanthamoeba/tratamento farmacológico , Acanthamoeba castellanii/efeitos dos fármacos , Acanthamoeba castellanii/crescimento & desenvolvimento , Acanthamoeba castellanii/fisiologia , Animais , Relação Dose-Resposta a Droga , Humanos , Nitrilos/uso terapêutico , Encistamento de Parasitas/efeitos dos fármacos , Testes de Sensibilidade Parasitária , Piridinas/uso terapêutico , Triazóis/uso terapêutico , Trofozoítos/efeitos dos fármacos
7.
Acta Trop ; 203: 105322, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31887263

RESUMO

Acanthamoeba spp. are free-living amoebae isolated from many ecological areas such as swimming pools, dams and lakes, and soil. Granulomatous amebic encephalitis and amebic keratitis, caused by Acanthamoeba spp., usually occurs in chronically ill, debilitated individuals, in immunosuppressed patients and treatment is quite difficult. This study aimed to determine the effect of benzothiazole on trophozoite and cyst forms of Acanthamoeba castellanii (A.castellanii). Axenic cultures of A. castellanii trophozoites and cysts were prepared to test the amoebicidal activity of benzothiazole. The concentrations of benzothiazole in 24-well plates were prepared as 0.08%, 0.04%, 0.02%, 0.01%, 0.005%, and A. castellanii cysts and trophozoites were added to these cultures. Parasites were counted at 0, ½, 1, 3, 6, 12, 24 and 48 h in the cell counter after staining with trypan blue. Cytotoxicity of benzothiazole on the WI-38 human fibroblast cell line was also tested. Between 0.08% and 0.01% concentrations of benzothiazole showed a strong amoebicidal activity at 24 and 48 h. A significant decrease in 0.005% concentration in the number of live trophozoites and cysts was detected between 6 and 48 h. As a result of the cytotoxicity studies, benzothiazole did not show any cytotoxic effect on the WI-38 human fibroblast cell line even at 1% concentration. Benzothiazole could be concluded as a new therapeutic agent against Acanthamoeba. On the other hand, in vivo studies are needed to confirm the efficacy of the biological effect.


Assuntos
Acanthamoeba castellanii/efeitos dos fármacos , Amebicidas/farmacologia , Benzotiazóis/farmacologia , Trofozoítos/efeitos dos fármacos , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Humanos
8.
Acta Microbiol Immunol Hung ; 67(1): 23-32, 2019 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-31833381

RESUMO

We aimed to compare LDH release assay, trypan blue and fluorescent stainings, and non-nutrient Escherichia coli plate assay in determining treatment efficacy of antiamoebic agents against Acanthamoeba castellanii trophozoites/cysts, in vitro. 1BU trophozoites/cysts were challenged with 0.02% polyhexamethylene biguanid (PHMB), 0.1% propamidine isethionate (PD), and 0.0065% miltefosine (MF). Efficacies of the drugs were determined by LDH release and trypan blue assays, by Hoechst 33343, calcein-AM, and ethidium homodimer-1 fluorescent dyes, and by a non-nutrient agar E. coli plate assay. All three antiamoebic agents induced a significant LDH release from trophozoites, compared to controls (p < 0.0001). Fluorescent-dye staining in untreated 1BU trophozoites/cysts was negligible, but using antiamoebic agents, there was 59.3%-100% trypan blue, 100% Hoechst 33342, 0%-75.3% calcein-AM, and 100% ethidium homodimer-1 positivity. On E. coli plates, in controls and MF-treated 1BU trophozoites/cysts, new trophozoites appeared within 24 h, encystment occurred after 5 weeks. In PHMB- and PD-treated 1BU throphozoites/cysts, irregularly shaped, smaller trophozoites appeared after 72 h, which failed to form new cysts within 5 weeks. None of the enzymatic- and dye-based viability assays tested here generated survival rates for trophozoites/cysts that were comparable with those yielded with the non-nutrient agar E. coli plate assay, suggesting that the culture-based assay is the best method to study the treatment efficacy of drugs against Acanthamoeba.


Assuntos
Acanthamoeba castellanii/efeitos dos fármacos , Antiparasitários/farmacologia , Testes de Sensibilidade Parasitária/métodos , Trofozoítos/efeitos dos fármacos , Escherichia coli , Fluorescência , L-Lactato Desidrogenase/análise , Coloração e Rotulagem
9.
ACS Infect Dis ; 5(12): 2039-2046, 2019 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-31612700

RESUMO

Brain-eating amoebae cause devastating infections in the central nervous system of humans, resulting in a mortality rate of 95%. There are limited effective therapeutic options available clinically for treating granulomatous amoebic encephalitis and primary amoebic meningoencephalitis caused by Acanthamoeba castellanii (A. castellanii) and Naegleria fowleri (N. fowleri), respectively. Here, we report for the first time that guanabenz conjugated to gold and silver nanoparticles has significant antiamoebic activity against both A. castellanii and N. fowleri. Gold and silver conjugated guanabenz nanoparticles were synthesized by the one-phase reduction method and were characterized by ultraviolet-visible spectrophotometry and atomic force microscopy. Both metals were facilely stabilized by the coating of guanabenz, which was examined by surface plasmon resonance determination. The average size of gold nanoconjugated guanabenz was found to be 60 nm, whereas silver nanoparticles were produced in a larger size distribution with the average diameter of around 100 nm. Guanabenz and its noble metal nanoconjugates exhibited potent antiamoebic effects in the range of 2.5 to 100 µM against both amoebae. Nanoparticle conjugation enhanced the antiamoebic effects of guanabenz, as more potent activity was observed at a lower effective concentration (2.5 and 5 µM) compared to the drug alone. Moreover, encystation and excystation assays revealed that guanabenz inhibits the interconversion between the trophozoite and cyst forms of A. castellanii. Cysticdal effects against N. fowleri were also observed. Notably, pretreatment of A. castellanii with guanabenz and its nanoconjugates exhibited a significant reduction in the host cell cytopathogenicity from 65% to 38% and 2% in case of gold and silver nanoconjugates, respectively. Moreover, the cytotoxic evaluation of guanabenz and its nanoconjugates revealed negligible cytotoxicity against human cells. Guanabenz is already approved for hypertension and crosses the blood-brain barrier; the results of our current study suggest that guanabenz and its conjugated gold and silver nanoparticles can be repurposed as a potential drug for treating brain-eating amoebic infections.


Assuntos
Acanthamoeba castellanii/efeitos dos fármacos , Ouro/química , Guanabenzo/farmacologia , Naegleria fowleri/efeitos dos fármacos , Prata/química , Acanthamoeba castellanii/crescimento & desenvolvimento , Amebicidas/química , Amebicidas/farmacologia , Linhagem Celular , Reposicionamento de Medicamentos , Guanabenzo/química , Células HeLa , Humanos , Nanopartículas Metálicas , Microscopia de Força Atômica , Estrutura Molecular , Naegleria fowleri/crescimento & desenvolvimento , Nanoconjugados/química , Tamanho da Partícula , Trofozoítos/efeitos dos fármacos
10.
Sci Transl Med ; 11(510)2019 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-31534021

RESUMO

Malaria eradication is critically dependent on new therapeutics that target resistant Plasmodium parasites and block transmission of the disease. Here, we report that pantothenamide bioisosteres were active against blood-stage Plasmodium falciparum parasites and also blocked transmission of sexual stages to the mosquito vector. These compounds were resistant to degradation by serum pantetheinases, showed favorable pharmacokinetic properties, and cleared parasites in a humanized mouse model of P. falciparum infection. Metabolomics revealed that coenzyme A biosynthetic enzymes converted pantothenamides into coenzyme A analogs that interfered with parasite acetyl-coenzyme A anabolism. Resistant parasites generated in vitro showed mutations in acetyl-coenzyme A synthetase and acyl-coenzyme A synthetase 11. Introduction and reversion of these mutations in P. falciparum using CRISPR-Cas9 gene editing confirmed the roles of these enzymes in the sensitivity of the malaria parasites to pantothenamides. These pantothenamide compounds with a new mode of action may have potential as drugs against malaria parasites.


Assuntos
Acetilcoenzima A/biossíntese , Antimaláricos/farmacologia , Vias Biossintéticas/efeitos dos fármacos , Ácido Pantotênico/análogos & derivados , Ácido Pantotênico/farmacologia , Plasmodium falciparum/metabolismo , Animais , Antimaláricos/química , Antimaláricos/farmacocinética , Modelos Animais de Doenças , Resistência a Medicamentos/efeitos dos fármacos , Humanos , Malária Falciparum/parasitologia , Malária Falciparum/transmissão , Masculino , Camundongos Endogâmicos BALB C , Mutação/genética , Ácido Pantotênico/química , Parasitemia/tratamento farmacológico , Parasitos/efeitos dos fármacos , Parasitos/metabolismo , Proteínas de Protozoários/genética , Reprodução Assexuada/efeitos dos fármacos , Resultado do Tratamento , Trofozoítos/efeitos dos fármacos , Trofozoítos/metabolismo
11.
Photodiagnosis Photodyn Ther ; 28: 166-171, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31499180

RESUMO

BACKGROUND: Microbial keratitis is a potential cause of corneal blindness. We investigated the amoebicidal efficacy of photodynamic antimicrobial therapy with a light-emitting diode as the light source and the cationic chlorin derivative TONS504 as the photosensitizer for the elimination of Acanthamoeba, a causative organism of corneal infection and blindness. Acanthamoeba keratitis remains a challenge to treat because of limited available treatments. METHODS: Acanthamoeba castellani 50370 was exposed to TONS504 at various concentrations (0, 1, or 10 mg/L for trophozoites; 0, 1, 10, or 20 mg/L for cysts), irradiated at various light energies (0, 10, or 30 J/cm2 for trophozoites; 0, 30, or 60 J/cm2 for cysts), and incubated at 26 °C for 3 h. Assessment of cell viability by trypan blue staining revealed that photodynamic antimicrobial therapy attenuated the survival of trophozoites and cysts dependent on TONS504 concentration and light energy. RESULTS: Photodynamic antimicrobial therapy with 10 mg/L TONS504 and 30 J/cm2 light energy suppressed trophozoite viability by 77%, and 20 mg/L TONS504 and 60 J/cm2 light energy attenuated cyst survival by 42%. Staining with fluorescein isothiocyanate-conjugated annexin V and ethidium homodimer III revealed photodynamic antimicrobial therapy induced apoptosis and necrosis in trophozoites dependent upon the intensity of treatment, whereas apoptosis was the predominant form of cell death in cysts. CONCLUSIONS: Photodynamic antimicrobial therapy with TONS504 warrants further investigation as a potential treatment modality for Acanthamoeba keratitis.


Assuntos
Amebíase/tratamento farmacológico , Ceratite/tratamento farmacológico , Ceratite/parasitologia , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/farmacologia , Porfirinas/farmacologia , Acanthamoeba castellanii/efeitos dos fármacos , Amebíase/parasitologia , Amebicidas/farmacologia , Animais , Oocistos/efeitos dos fármacos , Trofozoítos/efeitos dos fármacos
12.
Sci Rep ; 9(1): 11651, 2019 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-31406269

RESUMO

Recently, the search for novel therapeutic agents against Acanthamoeba species has been focused on the evaluation of natural resources. Among them, marine microorganisms have risen as a source of bioactive compounds with the advantage of the ability to obtain unlimited and constant amounts of the compounds in contrast to other natural sources such as plants. Furthermore, marine actinomycetes have recently been reported as highly rich in bioactive agents including salinosporamides, xiamycines, indolocarbazoles, naphtyridines, phenols, dilactones such as antimycines and macrolides among others. In this study, staurosporine (STS) was isolated from a strain of Streptomyces sanyensis and tested against Acanthamoeba to characterize the therapeutic potential of STS against this protozoan parasite. We have established that STS is active against both stages of the Acanthamoeba life cycle, by the activation of Programmed Cell Death via the mitochondrial pathway of the trophozoite. We have also established that STS has relatively low toxicity towards a macrophage cell line. However, previous studies have highlighted higher toxicity levels induced on other vertebrate cell lines and future research to lower these toxicity issues should be developed.


Assuntos
Acanthamoeba castellanii/efeitos dos fármacos , Amebicidas/farmacologia , Organismos Aquáticos/química , Estaurosporina/farmacologia , Streptomyces/química , Acanthamoeba castellanii/citologia , Amebíase/tratamento farmacológico , Amebíase/parasitologia , Amebicidas/isolamento & purificação , Amebicidas/uso terapêutico , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Humanos , Macrófagos/efeitos dos fármacos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Mitocôndrias/efeitos dos fármacos , Estaurosporina/isolamento & purificação , Estaurosporina/uso terapêutico , Testes de Toxicidade Aguda , Trofozoítos/citologia , Trofozoítos/efeitos dos fármacos
13.
Mar Drugs ; 17(7)2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31331002

RESUMO

Acanthamoeba genus is a widely distributed and opportunistic parasite with increasing importance worldwide as an emerging pathogen in the past decades. This protozoan has an active trophozoite stage, a cyst stage, and is dormant and very resistant. It can cause Acanthamoeba keratitis, an ocular sight-threatening disease, and granulomatous amoebic encephalitis, a chronic, very fatal brain pathology. In this study, the amoebicidal activity of sixteen Laurencia oxasqualenoid metabolites and semisynthetic derivatives were tested against Acanthamoeba castellanii Neff. The results obtained point out that iubol (3) and dehydrothyrsiferol (1) possess potent activities, with IC50 values of 5.30 and 12.83 µM, respectively. The hydroxylated congeners thyrsiferol (2) and 22-hydroxydehydrothyrsiferol (4), active in the same value range at IC50 13.97 and 17.00 µM, are not toxic against murine macrophages; thus, they are solid candidates for the development of new amoebicidal therapies.


Assuntos
Acanthamoeba castellanii/efeitos dos fármacos , Amebicidas/farmacologia , Laurencia/química , Extratos Vegetais/farmacologia , Esqualeno/farmacologia , Amebicidas/isolamento & purificação , Animais , Linhagem Celular , Furanos/isolamento & purificação , Furanos/farmacologia , Concentração Inibidora 50 , Macrófagos , Camundongos , Extratos Vegetais/isolamento & purificação , Piranos/isolamento & purificação , Piranos/farmacologia , Esqualeno/análogos & derivados , Esqualeno/isolamento & purificação , Testes de Toxicidade , Trofozoítos/efeitos dos fármacos
15.
J Infect Chemother ; 25(12): 955-964, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31189504

RESUMO

Trichomonas vaginalis (T. vaginalis) is a common sexually transmitted infection, affecting the urogenital tract. Trichomoniasis is customarily treated with metronidazole (MTZ). MTZ is known to cause undesirable side effects and there is several reports on MTZ resistant T. vaginalis. Thus, the present study aimed to in-vitro evaluate the activity of DNA minor groove binder drug ''Netropsin dihydrochloride'' against metronidazole-sensitive T. vaginalis isolates (G and U isolates) and resistant T. vaginalis isolate (ATCC50138) (R isolate). Netropsin was tested at concentrations ranging from 3.5 to 200 µg/ml. It showed effectiveness against all isolates with MLC of 12.5 µg/ml for G and U isolates and of 25 µg/ml for R isolate. Cytotoxicity assay of isolates exposed to the respective MLC of netropsin for 42 h showed a highly significant reduction in the death percentage of MCDK cell line as compared to the effect elicited by drug free controls. The hemolytic activity was evaluated by hemolytic assay and by monitoring the interaction of T. vaginalis isolates with human erythrocytes by inverted microscopy and scanning electron microscopy. The hemolytic assay showed (0%) hemolysis of RBCs incubated with T. vaginalis isolates treated with the corresponding MLC of netropsin for 24 h. Scanning electron microscopy revealed cytoskeletal deformities of netropsin treated isolates. Taken together, these observations suggest that netropsin is a promising therapy for T. vaginalis infection affecting its viability, virulence, cytopathogenic and hemolytic activity with a mechanism of action that might overcome T. vaginalis resistance to metronidazole.


Assuntos
Antibacterianos/farmacologia , Netropsina/farmacologia , Vaginite por Trichomonas/tratamento farmacológico , Trichomonas vaginalis/efeitos dos fármacos , Animais , Antibacterianos/uso terapêutico , Cães , Resistência a Medicamentos , Feminino , Hemólise/imunologia , Humanos , Células Madin Darby de Rim Canino , Metronidazol/farmacologia , Metronidazol/uso terapêutico , Netropsina/uso terapêutico , Testes de Sensibilidade Parasitária , Vaginite por Trichomonas/parasitologia , Trichomonas vaginalis/imunologia , Trichomonas vaginalis/isolamento & purificação , Trichomonas vaginalis/patogenicidade , Trofozoítos/efeitos dos fármacos , Trofozoítos/imunologia , Vagina/parasitologia
16.
Cell Microbiol ; 21(10): e13071, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31219662

RESUMO

Movement and phagocytosis are clue events in colonisation and invasion of tissues by Entamoeba histolytica, the protozoan causative of human amoebiasis. During phagocytosis, EhRab proteins interact with other functional molecules, conducting them to the precise cellular site. The gene encoding EhrabB is located in the complementary chain of the DNA fragment containing Ehcp112 and Ehadh genes, which encode for the proteins of the EhCPADH complex, involved in phagocytosis. This particular genetic organisation suggests that the three corresponding proteins may be functionally related. Here, we studied the relationship of EhRabB with EhCPADH and actin during phagocytosis. First, we obtained the EhRabB 3D structure to carry out docking analysis to predict the interaction sites involved in the EhRabB protein and the EhCPADH complex contact. By confocal microscopy, transmission electron microscopy, and immunoprecipitation assays, we revealed the interaction among these proteins when they move through different vesicles formed during phagocytosis. The role of the actin cytoskeleton in this event was also confirmed using Latrunculin A to interfere with actin polymerisation. This affected the movement of EhRabB and EhCPADH, as well as the rate of phagocytosis. Mutant trophozoites, silenced in EhrabB gene, evidenced the interaction of this molecule with EhCPADH and strengthened the role of actin during erythrophagocytosis.


Assuntos
Citoesqueleto de Actina/ultraestrutura , Entamoeba histolytica/metabolismo , Fagocitose/genética , Trofozoítos/ultraestrutura , Proteínas rab de Ligação ao GTP/química , Proteínas rab de Ligação ao GTP/metabolismo , Citoesqueleto de Actina/efeitos dos fármacos , Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Actinas/ultraestrutura , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Entamoeba histolytica/genética , Entamoeba histolytica/patogenicidade , Entamoeba histolytica/ultraestrutura , Eritrócitos/parasitologia , Eritrócitos/ultraestrutura , Humanos , Microscopia Eletrônica de Transmissão , Simulação de Dinâmica Molecular , Mutação , Proteínas de Protozoários/química , Proteínas de Protozoários/metabolismo , Trofozoítos/efeitos dos fármacos , Trofozoítos/metabolismo , Proteínas rab de Ligação ao GTP/genética
17.
Parasit Vectors ; 12(1): 280, 2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31159839

RESUMO

BACKGROUND: Species of Acanthamoeba are facultative pathogens which can cause sight threatening Acanthamoeba keratitis and a rare but deadly brain infection, granulomatous amoebic encephalitis. Due to conversion of Acanthamoeba trophozoites to resistant cyst stage, most drugs are found to be ineffective at preventing recurrence of infection. This study was designed to test the antiacanthamoebic effects of different cobalt nanoparticles (CoNPs) against trophozoites and cysts, as well as parasite-mediated host cell cytotoxicity. METHODS: Three different varieties of CoNPs were synthesized by utilizing hydrothermal and ultrasonication methods and were thoroughly characterized by X-ray diffraction and field emission scanning electron microscopy. Amoebicidal, encystation, excystation, and host cell cytopathogenicity assays were conducted to study the antiacanthamoebic effects of CoNPs. RESULTS: The results of the antimicrobial evaluation revealed that cobalt phosphate Co3(PO4)2 hexagonal microflakes, and 100 nm large cobalt hydroxide (Co(OH)2) nanoflakes showed potent amoebicidal activity at 100 and 10 µg/ml against Acanthamoeba castellanii as compared to granular cobalt oxide (Co3O4) of size 35-40 nm. Furthermore, encystation and excystation assays also showed consistent inhibition at 100 µg/ml. CoNPs also inhibited amoebae-mediated host cell cytotoxicity as determined by lactate dehydrogenase release without causing significant damage to human cells when treated alone. CONCLUSIONS: To our knowledge, these findings determined, for the first time, the effects of composition, size and morphology of CoNPs against A. castellanii. Co3(PO4)2 hexagonal microflakes showed the most promising antiamoebic effects as compared to Co(OH)2 nanoflakes and granular Co3O4. The results reported in the present study hold potential for the development of antiamoebic nanomedicine.


Assuntos
Acanthamoeba castellanii/efeitos dos fármacos , Amebicidas/farmacologia , Cobalto/farmacologia , Nanopartículas/química , Amebíase/tratamento farmacológico , Células Cultivadas , Microscopia Eletrônica de Varredura , Trofozoítos/efeitos dos fármacos
18.
Exp Parasitol ; 201: 90-92, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31059693

RESUMO

Acanthamoeba are free living amoeba that have been isolated from different environments like soil, water, air dust. Moreover, they are also able to act as opportunist pathogens, mainly causing a fatal encephalitis and also keratitis in both human and animals. This study was aimed to evaluate the activity of the Medicines for Malaria Venture (MMV) compounds against the trophozoite stage of Acanthamoeba castellanii Neff. Sixteen compounds showed ≥90% inhibition of parasite growth in the initial screen (10 µM). Those set were further evaluated to determine the inhibitor concentration that inhibit the 50% of the initial population and cytotoxicity against murine macrophages. Among the compounds included in the pathogen box, pentamidine and posaconazole were the most effective against this parasite with an of IC50 of 0.567 ±â€¯0.04 and 0.630 ±â€¯0.11, respectively.


Assuntos
Acanthamoeba castellanii/efeitos dos fármacos , Amebicidas/farmacologia , Amebicidas/classificação , Animais , Linhagem Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Concentração Inibidora 50 , Camundongos , Pentamidina/farmacologia , Triazóis/farmacologia , Trofozoítos/efeitos dos fármacos
19.
Parasitol Res ; 118(6): 1953-1961, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31069536

RESUMO

The genus Acanthamoeba can cause Acanthamoeba keratitis (AK) and granulomatous amoebic encephalitis (GAE). The treatment of these illnesses is hampered by the existence of a resistance stage that many times causes infection relapses. In an attempt to add new agents to our chemotherapeutic arsenal against acanthamebiasis, two Acanthamoeba isolates were treated in vitro with newly synthesized biguanide dendrimers. Trophozoite viability analysis and ultrastructural studies showed that dendrimers prevent encystment by lysing the cellular membrane of the amoeba. Moreover, one of the dendrimers showed low toxicity when tested on mammalian cell cultures, which suggest that it might be eventually used as an amoebicidal drug or as a disinfection compound in contact lens solutions.


Assuntos
Ceratite por Acanthamoeba/tratamento farmacológico , Acanthamoeba/efeitos dos fármacos , Amebicidas/farmacologia , Biguanidas/farmacologia , Clorexidina/análogos & derivados , Dendrímeros/farmacologia , Encefalite/tratamento farmacológico , Acanthamoeba/classificação , Acanthamoeba/isolamento & purificação , Animais , Linhagem Celular Tumoral , Clorexidina/farmacologia , Soluções para Lentes de Contato , Encefalite/parasitologia , Células HeLa , Humanos , Trofozoítos/efeitos dos fármacos
20.
Molecules ; 24(10)2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-31137574

RESUMO

Malaria is an infectious disease caused by Plasmodium group. The mechanisms of antimalarial drugs DHA/CQ are still unclear today. The inhibitory effects (IC50) of single treatments with DHA/CQ or V-ATPase inhibitor Baf-A1 or combination treatments by DHA/CQ combined with Baf-A1 on the growth of Plasmodium falciparum strain 3D7 was investigated. Intracellular cytoplasmic pH and labile iron pool (LIP) were labeled by pH probe BCECF, AM and iron probe calcein, AM, the fluorescence of the probes was measured by FCM. The effects of low doses of DHA (0.2 nM, 0.4 nM, 0.8 nM) on gene expression of V-ATPases (vapE, vapA, vapG) located in the membrane of DV were tested by RT-qPCR. DHA combined with Baf-A1 showed a synergism effect (CI = 0.524) on the parasite growth in the concentration of IC50. Intracellular pH and irons were effected significantly by different doses of DHA/Baf-A1. Intracellular pH was decreased by CQ combined with Baf-A1 in the concentration of IC50. Intracellular LIP was increased by DHA combined with Baf-A1 in the concentration of 20 IC50. The expression of gene vapA was down-regulated by all low doses of DHA (0.2/0.4/0.8 nM) significantly (p < 0.001) and the expression of vapG/vapE were up-regulated by 0.8 nM DHA significantly (p < 0.001). Interacting with ferrous irons, affecting the DV membrane proton pumping and acidic pH or cytoplasmic irons homeostasis may be the antimalarial mechanism of DHA while CQ showed an effect on cytoplasmic pH of parasite in vitro. Lastly, this article provides us preliminary results and a new idea for antimalarial drugs combination and new potential antimalarial combination therapies.


Assuntos
Artemisininas/farmacologia , Cloroquina/farmacologia , Eritrócitos/parasitologia , Homeostase , Estágios do Ciclo de Vida/efeitos dos fármacos , Plasmodium falciparum/crescimento & desenvolvimento , Animais , Antimaláricos/farmacologia , Membrana Celular/efeitos dos fármacos , Membrana Celular/parasitologia , Quimioterapia Combinada , Eritrócitos/efeitos dos fármacos , Fluorescência , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Concentração Inibidora 50 , Ferro/metabolismo , Macrolídeos/farmacologia , Parasitos/efeitos dos fármacos , Parasitos/crescimento & desenvolvimento , Testes de Sensibilidade Parasitária , Plasmodium falciparum/efeitos dos fármacos , Trofozoítos/efeitos dos fármacos , ATPases Vacuolares Próton-Translocadoras/genética , ATPases Vacuolares Próton-Translocadoras/metabolismo
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