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1.
Exp Parasitol ; 221: 108061, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33383023

RESUMO

Chagas disease (CD) caused by Trypanosoma cruzi remains a serious public health problem in Latin America. The available treatment is limited to two old drugs, benznidazole (Bz) and nifurtimox, which exhibit limited efficacy and trigger side effects, justifying the search for new therapies. Also, more accurate and sensitive experimental protocols for drug discovery programs are necessary to shrink the translational gaps found among pre-clinical and clinical trials. Presently, cardiac spheroids were used to evaluate host cell cytotoxicity and anti-T.cruzi activity of benznidazole, exploring its effect on the release of inflammatory mediators. Bz presented low toxic profile on 3D matrices (LC50 > 200 µM) and high potency in vitro (EC50 = 0.99 µM) evidenced by qPCR analysis of T.cruzi-infected cardiac spheroids. Flow cytometry appraisal of inflammatory mediators released at the cellular supernatant showed increases in IL - 6 and TNF contents (≈190 and ≈ 25-fold) in parasitized spheroids as compared to uninfected cultures. Bz at 10 µM suppressed parasite load (92%) concomitantly decreasing in IL-6 (36%) and TNF (68%). Our findings corroborate the successful use of 3D cardiac matrices for in vitro identification of novel anti-parasitic agents and potential impact in host cell physiology.


Assuntos
Nitroimidazóis/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Imageamento Tridimensional , Camundongos , Microscopia de Fluorescência , Conformação Molecular , Esferoides Celulares , Trypanosoma cruzi/crescimento & desenvolvimento
2.
PLoS Negl Trop Dis ; 14(12): e0008919, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33382717

RESUMO

BACKGROUND: Ghana is endemic for some neglected tropical diseases (NTDs) including schistosomiasis, onchocerciasis and lymphatic filariasis. The major intervention for these diseases is mass drug administration of a few repeatedly recycled drugs which is a cause for major concern due to reduced efficacy of the drugs and the emergence of drug resistance. Evidently, new treatments are needed urgently. Medicinal plants, on the other hand, have a reputable history as important sources of potent therapeutic agents in the treatment of various diseases among African populations, Ghana inclusively, and provide very useful starting points for the discovery of much-needed new or alternative drugs. METHODOLOGY/PRINCIPAL FINDINGS: In this study, extracts of fifteen traditional medicines used for treating various NTDs in local communities were screened in vitro for efficacy against schistosomiasis, onchocerciasis and African trypanosomiasis. Two extracts, NTD-B4-DCM and NTD-B7-DCM, prepared from traditional medicines used to treat schistosomiasis, displayed the highest activity (IC50 = 30.5 µg/mL and 30.8 µg/mL, respectively) against Schistosoma mansoni adult worms. NTD-B2-DCM, also obtained from an antischistosomal remedy, was the most active against female and male adult Onchocera ochengi worms (IC50 = 76.2 µg/mL and 76.7 µg/mL, respectively). Antitrypanosomal assay of the extracts against Trypanosoma brucei brucei gave the most promising results (IC50 = 5.63 µg/mL to 18.71 µg/mL). Incidentally, NTD-B4-DCM and NTD-B2-DCM, also exhibited the greatest antitrypanosomal activities (IC50 = 5.63 µg/mL and 7.12 µg/mL, respectively). Following the favourable outcome of the antitrypanosomal screening, this assay was selected for bioactivity-guided fractionation. NTD-B4-DCM, the most active extract, was fractionated and subsequent isolation of bioactive constituents led to an eupatoriochromene-rich oil (42.6%) which was 1.3-fold (IC50 <0.0977 µg/mL) more active than the standard antitrypanosomal drug, diminazene aceturate (IC50 = 0.13 µg/mL). CONCLUSION/SIGNIFICANCE: These findings justify the use of traditional medicines and demonstrate their prospects towards NTDs drug discovery.


Assuntos
Filaricidas/farmacologia , Onchocerca/efeitos dos fármacos , Schistosoma mansoni/efeitos dos fármacos , Esquistossomicidas/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos , Animais , Gana , Medicina Tradicional Africana , Doenças Negligenciadas/tratamento farmacológico , Doenças Negligenciadas/parasitologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Plantas Medicinais/química
3.
Parasitol Res ; 119(10): 3481-3489, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32869169

RESUMO

Trypanosoma evansi, an extracellular haemoflagellate, has a wide range of hosts receptive and susceptible to infection, in which it revealed highly inconsistent clinical effects. Drugs used for the treatment of trypanosomosis have been utilized for more than five decades and have several problems like local and systemic toxicity. In the present investigation, imatinib and sorafenib were selected as drugs as they are reported to have the potential to cause reactive oxygen species (ROS)-mediated effect in cancer cells. Both have also been reported to have potential against T. brucei, T. cruzi and Leishmania donovani. To date, imatinib and sorafenib have not evaluated for their growth inhibitory effect against T. evansi. Imatinib and sorafenib showed significant (p < 0.001) inhibition on parasite growth and multiplication with IC50 (50% inhibitory concentration) values 6.12 µM and 0.33 µM respectively against T. evansi. Both the drug molecules demonstrated for the generation of ROS in T. evansi and were found up to 65% increased level of ROS as compared with negative control in the axenic culture system. Furthermore, different concentrations of imatinib and sorafenib were found non-toxic on horse peripheral blood mononuclear cells and Vero cell lines. Also, in conclusion, our results demonstrated that imatinib- and sorafenib-induced generation of ROS contributed inhibitory effect on the growth of Trypanosoma evansi in an axenic culture system.


Assuntos
Espécies Reativas de Oxigênio/metabolismo , Tripanossomicidas/farmacologia , Trypanosoma/efeitos dos fármacos , Trypanosoma/crescimento & desenvolvimento , Animais , Cultura Axênica , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Chlorocebus aethiops , Cavalos , Mesilato de Imatinib/farmacologia , Concentração Inibidora 50 , Leucócitos Mononucleares/efeitos dos fármacos , Sorafenibe/farmacologia , Trypanosoma/metabolismo , Células Vero
4.
Chem Biol Interact ; 330: 109165, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32771326

RESUMO

The effect of N-geranyl-ethane-1,2-diamine dihydochloride (GIB24), a synthetic diamine, was assayed against different developmental forms of the parasitic protozoan Trypanosoma cruzi (strain Dm28c). The compound was effective against culture epimastigote forms (IC50/24h = 5.64 µM; SI = 16.4) and intracellular amastigotes (IC50/24h = 12.89 µM; SI = 7.18), as detected by the MTT methodology and by cell counting, respectively. Incubation of epimastigotes for 6h with 6 µM GIB24 (IC50/24h value) resulted in significant dissipation of the mitochondrial membrane potential, prior to permeabilization of the plasma membrane. Rounded epimastigotes with cell size reduction were observed by scanning electron microscopy. These morpho-physiological changes induced by GIB24 suggest an incidental death process. Treatment of infected Vero cells did not prevent the intracellular amastigotes from completing the intracellular cycle. However, there was a decrease in the number of released parasites, increasing the ratio amastigotes/trypomastigotes. Proteomic analysis of 15 µM GIB24 resistant epimastigotes indicated that the compound acts mainly on mitochondrial components involved in the Krebs cycle and in maintaining the oxidative homeostasis of the parasites. Our data suggest that GIB24 is active against the main morphological forms of T. cruzi.


Assuntos
Diaminas/farmacologia , Resistência a Medicamentos , Espaço Intracelular/efeitos dos fármacos , Proteômica , Terpenos/química , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/crescimento & desenvolvimento , Animais , Chlorocebus aethiops , Diaminas/química , Espaço Intracelular/parasitologia , Tripanossomicidas/química , Tripanossomicidas/farmacologia , Trypanosoma cruzi/metabolismo , Células Vero
5.
PLoS Negl Trop Dis ; 14(7): e0008487, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32716934

RESUMO

New assay designs are needed to improve the predictive value of the Trypanosoma cruzi in vitro tests used as part of the Chagas' disease drug development pipeline. Here, we employed a green fluorescent protein (eGFP)-expressing parasite line and live high-content imaging to monitor the growth of T. cruzi amastigotes in mouse embryonic fibroblasts. A novel assay design allowed us to follow parasite numbers over 6 days, in four-hour intervals, while occupying the microscope for only 24 hours per biological replicate. Dose-response curves were calculated for each time point after addition of test compounds, revealing how EC50 values first decreased over the time of drug exposure, and then leveled off. However, we observed that parasite numbers could vary, even in the untreated controls, and at different sites in the same well, which caused variability in the EC50 values. To overcome this, we established that fold change in parasite number per hour is a more robust and informative measure of drug activity. This was calculated based on an exponential growth model for every biological sample. The net fold change per hour is the result of parasite replication, differentiation, and death. The calculation of this fold change enabled us to determine the tipping point of drug action, i.e. the time point when the death rate of the parasites exceeded the growth rate and the fold change dropped below 1, depending on the drug concentration and exposure time. This revealed specific pharmacodynamic profiles of the benchmark drugs benznidazole and posaconazole.


Assuntos
Doença de Chagas/tratamento farmacológico , Descoberta de Drogas , Tripanossomicidas/farmacologia , Humanos , Nitroimidazóis/farmacologia , Triazóis/farmacologia , Trypanosoma cruzi/efeitos dos fármacos
6.
Life Sci ; 257: 118067, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32652140

RESUMO

Although renin-angiotensin system (RAS) imbalance is manifested in cardiomyopathies with different etiologies, the impact of RAS effectors on Chagas cardiomyopathy and skeletal myositis is poorly understood. Given that diminazene aceturate (DMZ) shares trypanocidal, angiotensin-converting enzyme 2 (ACE2) and angiotensin-(1-7) stimulatory effects, we investigated the impact of DMZ on cardiomyocytes infection in vitro, renin-angiotensin system, Chagas cardiomyopathy and skeletal myositis in vivo. Cardiomyocytes and T. cruzi were used to evaluate DMZ toxicity in vitro. The impact of 20-days DMZ treatment (1 mg/kg) was also investigated in uninfected and T. cruzi-infected mice as follows: control uninfected and untreated, uninfected treated with DMZ, infected untreated and infected treated with DMZ. DMZ had low toxicity on cardiomyocytes, induced dose-dependent antiparasitic activity on T. cruzi trypomastigotes, and reduced parasite load but not infection rates in cardiomyocytes. DMZ increased ACE2 activity and angiotensin-(1-7) plasma levels but exerted no interference on angiotensin-converting enzyme (ACE) activity, ACE, ACE2 and angiotensin II levels in uninfected and infected mice. DMZ treatment also reduced IFN-γ and IL-2 circulating levels but was ineffective in attenuating parasitemia, MCP-1, IL-10, anti-T. cruzi IgG, nitrite/nitrate and malondialdehyde production, myocarditis and skeletal myositis compared to infected untreated animals. As the antiparasitic effect of DMZ in vitro did not manifest in vivo, this drug exhibited limited relevance to the treatment of Chagas disease. Although DMZ is effective in upregulating angiotensin-(1-7) levels, this molecule does not act as a potent modulator of T. cruzi infection, which can establish heart and skeletal muscle parasitism, lipid oxidation and inflammatory damage, even in the presence of high concentrations of this RAS effector.


Assuntos
Cardiomiopatia Chagásica/tratamento farmacológico , Doença de Chagas/tratamento farmacológico , Diminazena/análogos & derivados , Miócitos Cardíacos/efeitos dos fármacos , Sistema Renina-Angiotensina/efeitos dos fármacos , Angiotensina I/metabolismo , Animais , Linhagem Celular , Cardiomiopatia Chagásica/parasitologia , Doença de Chagas/parasitologia , Diminazena/administração & dosagem , Diminazena/farmacologia , Relação Dose-Resposta a Droga , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Miocardite/tratamento farmacológico , Miocardite/parasitologia , Miócitos Cardíacos/parasitologia , Miosite/tratamento farmacológico , Miosite/parasitologia , Fragmentos de Peptídeos/metabolismo , Ratos , Tripanossomicidas/administração & dosagem , Tripanossomicidas/farmacologia
7.
PLoS Negl Trop Dis ; 14(7): e0008458, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32644992

RESUMO

Defining mode of action is vital for both developing new drugs and predicting potential resistance mechanisms. Sensitivity of African trypanosomes to pentamidine and melarsoprol is predominantly mediated by aquaglyceroporin 2 (TbAQP2), a channel associated with water/glycerol transport. TbAQP2 is expressed at the flagellar pocket membrane and chimerisation with TbAQP3 renders parasites resistant to both drugs. Two models for how TbAQP2 mediates pentamidine sensitivity have emerged; that TbAQP2 mediates pentamidine translocation across the plasma membrane or via binding to TbAQP2, with subsequent endocytosis and presumably transport across the endosomal/lysosomal membrane, but as trafficking and regulation of TbAQPs is uncharacterised this remains unresolved. We demonstrate that TbAQP2 is organised as a high order complex, is ubiquitylated and is transported to the lysosome. Unexpectedly, mutation of potential ubiquitin conjugation sites, i.e. cytoplasmic-oriented lysine residues, reduced folding and tetramerization efficiency and triggered ER retention. Moreover, TbAQP2/TbAQP3 chimerisation, as observed in pentamidine-resistant parasites, also leads to impaired oligomerisation, mislocalisation and increased turnover. These data suggest that TbAQP2 stability is highly sensitive to mutation and that instability contributes towards the emergence of drug resistance.


Assuntos
Aquagliceroporinas/metabolismo , Resistência a Medicamentos , Tripanossomicidas/farmacologia , Trypanosoma brucei brucei , Tripanossomíase Africana/parasitologia , Sequência de Aminoácidos , Animais , Aquagliceroporinas/química , Estabilidade Proteica
8.
Parasitol Res ; 119(9): 2943-2954, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32607710

RESUMO

Trypanosomatidae is a family of unicellular parasites belonging to the phylum Euglenozoa, which are causative agents in high impact human diseases such as Leishmaniasis, Chagas disease and African sleeping sickness. The impact on human health and local economies, together with a lack of satisfactory chemotherapeutic treatments and effective vaccines, justifies stringent research efforts to search for new disease therapies. Here, we present in vitro trypanocidal activity data and mode of action data, repositioning leishmanicidal [1,2,3]Triazolo[1,5-a]pyridinium salts against Trypanosoma cruzi, the aetiological agent of Chagas disease. This disease is one of the most neglected tropical diseases and is a major public health issue in Central and South America. The disease affects approximately 6-7 million people and is widespread due to increased migratory movements. We screened a suite of leishmanicidal [1,2,3]Triazolo[1,5-a]pyridinium salt compounds, of which compounds 13, 20 and 21 were identified as trypanocidal drugs. These compounds caused cell death in a mitochondrion-dependent manner through a bioenergetic collapse. Moreover, compounds 13 and 20 showed a remarkable inhibition of iron superoxide dismutase activity of T. cruzi, a key enzyme in the protection from the damage produced by oxidative stress.


Assuntos
Doença de Chagas/tratamento farmacológico , Compostos de Piridínio/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Morte Celular/efeitos dos fármacos , Reposicionamento de Medicamentos , Humanos , Leishmaniose/tratamento farmacológico , Membranas Mitocondriais/metabolismo , Estresse Oxidativo/efeitos dos fármacos , América do Sul , Superóxido Dismutase/metabolismo , Tripanossomíase Africana/tratamento farmacológico
9.
J Nat Med ; 74(4): 702-709, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32529328

RESUMO

Africa Trypanosomiasis remains a serious health problem, but the approved drugs for this disease are so few that novel trypanocidal compounds are demanded. In search for trypanocidal principles from medicinal plants, we found MeOH extracts of Meliae Cortex with potent activity through the screening from about 300 kinds of methanolic extract. By bioassay-guided fractionation from this extract through the liquid-liquid partition and subsequent chromatographic technique using silica gel and ODS, finally we disclosed toosendanin (1) and its relatives as active principles. These active congeners showed not only potent trypanocidal activity but also little cytotoxicity to display the excellent selective index. Taking the isolated amount as well as trypanocidal activity into consideration, 1 was disclosed to be the responsible active principle in Meliae Cortex. Additionally, the derivatives of 1 were chemically prepared from 1 and bioactivity of them were also evaluated. Through the comparison with their trypanocidal activity among the isolated relatives and the synthesized derivatives of 1, the epoxide moiety was revealed to be essential for their potent trypanocidal activity. Furthermore, 3-O-acetyl group and 7-hydroxyl group were presumed to be important functional groups and introduction of methylpropionyl group into hemiacetal hydroxy moiety was clarified to enhance their typanocidal activity.


Assuntos
Medicamentos de Ervas Chinesas/química , Extratos Vegetais/química , Plantas Medicinais/química , Tripanossomicidas/uso terapêutico , Animais , Humanos , Estrutura Molecular , Tripanossomicidas/farmacologia
10.
Exp Parasitol ; 213: 107902, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32353376

RESUMO

Natural compounds played an important role for prevention and treatment of the disease as well as are the important compounds for the design of the new bioactive compounds. In this study, eight tropolone alkaloids were isolated from Colchicum kurdicum including colchicoside, 2-demethyl colchicine, 3-demethyl colchicine, demecolcine, colchifoline, N-deacetyl-N-formyl colchicine, colchicine and cornigerine by column and preparative thin layer chromatography. The chemical structures were identified by 1H NMR and 13C NMR spectroscopy. Moreover, the antileishmanial activity on Leishmania major, anti-inflammatory activity, iron chelating activity and toxicity studies including hemolytic activity, brine shrimp toxicity, cytotoxicity and acute toxicity and docking study of all isolated bioactive compounds were evaluated. As result, colchicoside and colchicine had potent leishmanicidal effects and N-deacetyl-N-formyl colchicine and cornigerine had the highest anti-inflammatory effects. All compounds had the significant iron chelating activity. According to toxicity studies, isolated compounds showed the low hemolytic activity and cytotoxicity, high LC50, LC90 and LD50. In the molecular docking study, colchicoside had the high dockscore. According to the study, with future studies all isolated compounds could be used for design the novel antileishmanial drugs.


Assuntos
Alcaloides/farmacologia , Colchicum/química , Leishmania major/efeitos dos fármacos , Extratos Vegetais/farmacologia , Tripanossomicidas/farmacologia , Alcaloides/química , Alcaloides/isolamento & purificação , Simulação de Acoplamento Molecular , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Tropolona/química , Tripanossomicidas/química , Tripanossomicidas/isolamento & purificação
11.
J Nat Med ; 74(3): 606-611, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32277328

RESUMO

Six limonoids [kotschyienone A and B (1, 2), 7-deacetylgedunin (3), 7-deacetyl-7-oxogedunin (4), andirobin (5) and methyl angolensate (6)] were investigated for their trypanocidal and leishmanicidal activities using bloodstream forms of Trypanosoma brucei and promastigotes of Leishmania major. Whereas all compounds showed anti-trypanosomal activity, only compounds 1-4 displayed anti-leishmanial activity. The 50% growth inhibition (GI50) values for the trypanocidal and leishmanicidal activity of the compounds ranged between 2.5 and 14.9 µM. Kotschyienone A (1) was found to be the most active compound with a minimal inhibition concentration (MIC) value of 10 µM and GI50 values between 2.5 and 2.9 µM. Only compounds 1 and 3 showed moderate cytotoxicity against HL-60 cells with MIC and GI50 values of 100 µM and 31.5-46.2 µM, respectively. Compound 1 was also found to show activity against intracellular amastigotes of L. major with a GI50 value of 1.5 µM. The results suggest that limonoids have potential as drug candidates for the development of new treatments against trypanosomiasis and leishmaniasis.


Assuntos
Leishmania major/efeitos dos fármacos , Leishmaniose/tratamento farmacológico , Limoninas/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos , Tripanossomíase/tratamento farmacológico , Animais , Células HL-60 , Humanos , Testes de Sensibilidade Microbiana
12.
J Med Chem ; 63(8): 4306-4314, 2020 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-32223141

RESUMO

We report for the first time a novel series of tellurides bearing sulfonamide as selective and potent inhibitors of the ß-class carbonic anhydrase (CA; EC 4.2.1.1) enzyme expressed in Leishmania donovani protozoa. Such derivatives showed high activity against axenic amastigotes, and among them, compound 5g (4-(((3,4,5-trimethoxyphenyl)tellanyl)methyl)benzenesulfonamide) showed an IC50 of 0.02 µM being highly selective for the parasites over THP-1 cells with a selectivity index of 300. The in vitro and in vivo toxicity experiments showed compound 5g to possess a safe profile and thus paving the way for tellurium-containing compounds as novel drug entities.


Assuntos
Inibidores da Anidrase Carbônica/farmacologia , Leishmania donovani/efeitos dos fármacos , Sulfonamidas/farmacologia , Tripanossomicidas/farmacologia , Animais , Inibidores da Anidrase Carbônica/química , Relação Dose-Resposta a Droga , Feminino , Jejuno/efeitos dos fármacos , Jejuno/patologia , Leishmania donovani/fisiologia , Técnicas de Cultura de Órgãos , Ratos , Ratos Wistar , Sulfonamidas/química , Tripanossomicidas/química
13.
Acta Trop ; 206: 105421, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32112721

RESUMO

The development of new drugs targeting neglected animal diseases is imperative. In Asia and South America, Trypanosoma evansi is a pathogen that affects horses and other species, causing economic losses associated with reduced animal productivity and death. In order to accelerate the identification of drugs with activity against neglected diseases, Medicines for Malaria Venture has developed Pathogen Box®, a library of 400 different molecules. The present work aimed to identify compounds present in the Pathogen Box® library, measuring in vitro activity against T. evansi. Among the 400 compounds, 5 showed anti-T.evansi activity: pentamidine, MMV688410, MMV687273, MMV022478 and auranofin. Suramin, a trypanocidal activity molecule present on the Pathogen Box® reference compound list, demonstrated no anti-T. evansi activity in the in vitro assays. MMV688410 is the most promising candidate because it induces death and reduces the number of parasites in cell culture, and mainly because its mechanism of action is probably associated with inhibition of trypanosomal reductase enzyme, an exclusive target of trypanosomatides. Further in vitro and in vivo assays are needed to determine the efficacy of the compounds identified in this work, especially by associating tissue distribution and the ability of drugs to cross the blood brain barrier, as T. evansi is able to invade the central nervous system.


Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Tripanossomicidas/farmacologia , Trypanosoma/efeitos dos fármacos , Animais , Camundongos
14.
J Med Chem ; 63(7): 3485-3507, 2020 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-32196340

RESUMO

Human African trypanosomiasis is causing thousands of deaths every year in the rural areas of Africa. In this manuscript we describe the optimization of a family of phtalazinone derivatives. Phosphodiesterases have emerged as attractive molecular targets for a novel treatment for a variety of neglected parasitic diseases. Compound 1 resulted in being a potent TbrPDEB1 inhibitor with interesting activity against T. brucei in a phenotypic screen. Derivative 1 was studied in an acute in vivo mouse disease model but unfortunately showed no efficacy due to low metabolic stability. We report structural modifications to achieve compounds with an improved metabolic stability while maintaining high potency against TbrPDEB1 and T. brucei. Compound 14 presented a good microsomal stability in mouse and human microsomes and provides a good starting point for future efforts.


Assuntos
Inibidores de Fosfodiesterase/farmacologia , Ftalazinas/farmacologia , Tripanossomicidas/farmacologia , Animais , Cristalografia por Raios X , Estabilidade de Medicamentos , Humanos , Camundongos , Microssomos Hepáticos/metabolismo , Estrutura Molecular , Testes de Sensibilidade Parasitária , Inibidores de Fosfodiesterase/síntese química , Inibidores de Fosfodiesterase/metabolismo , Diester Fosfórico Hidrolases/metabolismo , Ftalazinas/síntese química , Ftalazinas/metabolismo , Ligação Proteica , Proteínas de Protozoários/metabolismo , Relação Estrutura-Atividade , Tripanossomicidas/síntese química , Tripanossomicidas/metabolismo , Trypanosoma brucei brucei/efeitos dos fármacos
15.
PLoS Negl Trop Dis ; 14(3): e0007790, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32168320

RESUMO

Trypanosoma brucei are unicellular parasites endemic to Sub-Saharan Africa that cause fatal disease in humans and animals. Infection with these parasites is caused by the bite of the tsetse fly vector, and parasites living extracellularly in the blood of infected animals evade the host immune system through antigenic variation. Existing drugs for Human and Animal African Trypanosomiasis are difficult to administer and can have serious side effects. Resistance to some drugs is also increasing, creating an urgent need for alternative trypanosomiasis therapeutics. We screened a library of 1,585 U.S. or foreign-approved drugs and identified 154 compounds that inhibit trypanosome growth. As all of these compounds have already undergone testing for human toxicity, they represent good candidates for repurposing as trypanosome therapeutics. In addition to identifying drugs that inhibit trypanosome growth, we wished to identify small molecules that can induce bloodstream form parasites to differentiate into forms adapted for the insect vector. These insect stage parasites lack the immune evasion mechanisms prevalent in bloodstream forms, making them vulnerable to the host immune system. To identify drugs that increase transcript levels of an invariant, insect-stage specific surface protein called procyclin, we engineered bloodstream reporter parasites that express Green Fluorescent Protein (GFP) following induction or stabilization of the procyclin transcript. Using these bloodstream reporter strains in combination with automated flow cytometry, we identified eflornithine, spironolactone, and phenothiazine as small molecules that increase abundance of procyclin transcript. Both eflornithine and spironolactone also affect transcript levels for a subset of differentiation associated genes. While we failed to identify compounds that increase levels of procyclin protein on the cell surface, this study is proof of principle that these fluorescent reporter parasites represent a useful tool for future small molecule or genetic screens aimed at identifying molecules or processes that initiate remodeling of the parasite surface during life cycle stage transitions.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Reposicionamento de Medicamentos/métodos , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Tripanossomicidas/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei brucei/crescimento & desenvolvimento , Avaliação Pré-Clínica de Medicamentos/métodos , Eflornitina/farmacologia , Fenotiazinas/farmacologia , Espironolactona/farmacologia
16.
PLoS Negl Trop Dis ; 14(3): e0007755, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32163418

RESUMO

The cysteine protease cruzipain is considered to be a validated target for therapeutic intervention in the treatment of Chagas disease. A series of 26 new compounds were designed, synthesized, and tested against the recombinant cruzain (Cz) to map its S1/S1´ subsites. The same series was evaluated on a panel of four human cysteine proteases (CatB, CatK, CatL, CatS) and Leishmania mexicana CPB, which is a potential target for the treatment of cutaneous leishmaniasis. The synthesized compounds are dipeptidyl nitriles designed based on the most promising combinations of different moieties in P1 (ten), P2 (six), and P3 (four different building blocks). Eight compounds exhibited a Ki smaller than 20.0 nM for Cz, whereas three compounds met these criteria for LmCPB. Three inhibitors had an EC50 value of ca. 4.0 µM, thus being equipotent to benznidazole according to the antitrypanosomal effects. Our mapping approach and the respective structure-activity relationships provide insights into the specific ligand-target interactions for therapeutically relevant cysteine proteases.


Assuntos
Inibidores de Cisteína Proteinase/farmacologia , Dipeptídeos/farmacologia , Leishmania mexicana/enzimologia , Nitrilos/farmacologia , Proteínas de Protozoários/antagonistas & inibidores , Tripanossomicidas/farmacologia , Trypanosoma cruzi/enzimologia , Cisteína Endopeptidases , Cisteína Proteases/metabolismo , Humanos
17.
J Med Chem ; 63(6): 3298-3316, 2020 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-32125159

RESUMO

Cruzain, an essential cysteine protease of the parasitic protozoan, Trypanosoma cruzi, is an important drug target for Chagas disease. We describe here a new series of reversible but time-dependent inhibitors of cruzain, composed of a dipeptide scaffold appended to vinyl heterocycles meant to provide replacements for the irreversible reactive "warheads" of vinyl sulfone inactivators of cruzain. Peptidomimetic vinyl heterocyclic inhibitors (PVHIs) containing Cbz-Phe-Phe/homoPhe scaffolds with vinyl-2-pyrimidine, vinyl-2-pyridine, and vinyl-2-(N-methyl)-pyridine groups conferred reversible, time-dependent inhibition of cruzain (Ki* = 0.1-0.4 µM). These cruzain inhibitors exhibited moderate to excellent selectivity versus human cathepsins B, L, and S and showed no apparent toxicity to human cells but were effective in cell cultures of Trypanosoma brucei brucei (EC50 = 1-15 µM) and eliminated T. cruzi in infected murine cardiomyoblasts (EC50 = 5-8 µM). PVHIs represent a new class of cruzain inhibitors that could progress to viable candidate compounds to treat Chagas disease and human sleeping sickness.


Assuntos
Inibidores de Cisteína Proteinase/farmacologia , Peptidomiméticos/farmacologia , Proteínas de Protozoários/antagonistas & inibidores , Tripanossomicidas/farmacologia , Compostos de Vinila/farmacologia , Animais , Cisteína Endopeptidases/metabolismo , Inibidores de Cisteína Proteinase/síntese química , Inibidores de Cisteína Proteinase/metabolismo , Desenho de Fármacos , Ensaios Enzimáticos , Humanos , Cinética , Camundongos , Simulação de Acoplamento Molecular , Mioblastos Cardíacos/efeitos dos fármacos , Peptidomiméticos/síntese química , Peptidomiméticos/metabolismo , Ligação Proteica , Proteínas de Protozoários/metabolismo , Piridinas/síntese química , Piridinas/metabolismo , Piridinas/farmacologia , Pirimidinas/síntese química , Pirimidinas/metabolismo , Pirimidinas/farmacologia , Tripanossomicidas/síntese química , Tripanossomicidas/metabolismo , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma cruzi/efeitos dos fármacos , Compostos de Vinila/síntese química , Compostos de Vinila/metabolismo
18.
Curr Pharm Des ; 26(8): 838-866, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32039675

RESUMO

In this report, we extend the SAR analysis of a number of lipophilic guanylhydrazone analogues with respect to in vitro growth inhibition of Trypanosoma brucei and Trypanosoma cruzi. Sleeping sickness and Chagas disease, caused by the tropical parasites T. brucei and T. cruzi, constitute a significant socioeconomic burden in low-income countries of sub-Saharan Africa and Latin America, respectively. Drug development is underfunded. Moreover, current treatments are outdated and difficult to administer, while drug resistance is an emerging concern. The synthesis of adamantane-based compounds that have potential as antitrypanosomal agents is extensively reviewed. The critical role of the adamantane ring was further investigated by synthesizing and testing a number of novel lipophilic guanylhydrazones. The introduction of hydrophobic bulky substituents onto the adamantane ring generated the most active analogues, illustrating the synergistic effect of the lipophilic character of the C1 side chain and guanylhydrazone moiety on trypanocidal activity. The n-decyl C1-substituted compound G8 proved to be the most potent adamantane derivative against T. brucei with activity in the nanomolar range (EC50=90 nM). Molecular simulations were also performed to better understand the structure-activity relationships between the studied guanylhydrazone analogues and their potential enzyme target.


Assuntos
Mitoguazona/análogos & derivados , Tripanossomicidas , Trypanosoma brucei brucei , Trypanosoma cruzi , Mitoguazona/farmacologia , Relação Estrutura-Atividade , Tripanossomicidas/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma cruzi/efeitos dos fármacos
19.
Int J Nanomedicine ; 15: 965-979, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32103950

RESUMO

Background: Chagas disease, also known as American Trypanosomiasis, is caused by the protozoan Trypanosoma cruzi. It is occurring in Americas, including USA and Canada, and Europe and its current treatment involves the use of two drugs as follows: benznidazole (BNZ) and nifurtimox, which present high toxicity and low efficacy during the chronic phase of the disease, thus promoting the search for more effective therapeutic alternatives. Amongst them xylan, a bioactive polysaccharide, extracted from corn cob. Methods: Ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy (FITR), Raman spectroscopy, energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy, atomic force microscopy, plasma optical emission spectroscopy (ICP-OES), dynamic light scattering (DLS) have been used to characterize the silver-xylan nanoparticles (NX). Their cytotoxicity was evaluated with 3-bromo(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) test. MTT and flow cytometry were used to ascertain the anti-Trypanosoma cruzi activity. Results: UV-Vis spectroscopy gave plasmon resonance ranging between 400 and 450 nm while FITC and Raman spectroscopy proved nano interface functionalized with xylan. ICP-OES data showed NX with xylan (81%) and silver (19%). EDS showed NX consisting of carbon (59.4%), oxygen (26.2%) and silver (4.8%) main elements. Spherical NX of 55 nm average size has been depicted with SEM and AFM, while DLS showed 102 ± 1.7 nm NX. The NX displayed negligible cytotoxicity (2000 µg/mL). NX (100 µg/mL) was more effective, regardless of experiment time, in affecting the ability of parasites to reduce MTT than BZN (100 µg/mL). In addition, NX (100 µg/mL) induced death of 95% of parasites by necrosis. Conclusion: This is the first time silver nanoparticles are presented as an anti-Trypanosoma cruzi agent and the data point to the potential application of NX to new preclinical studies in vitro and in vivo.


Assuntos
Nanopartículas Metálicas/química , Prata/química , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Xilanos/química , Animais , Doença de Chagas/tratamento farmacológico , Difusão Dinâmica da Luz , Nanopartículas Metálicas/uso terapêutico , Camundongos , Microscopia de Força Atômica , Células RAW 264.7 , Espectrometria por Raios X , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Tripanossomicidas/síntese química , Zea mays/química
20.
Eur J Med Chem ; 188: 112018, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31931339

RESUMO

African trypanosomiasis, a deadly infectious disease caused by the protozoan Trypanosoma brucei spp., is spread to new hosts by bites of infected tsetse flies. Currently approved therapies all have their specific drawbacks, prompting a search for novel therapeutic agents. T. brucei lacks the enzymes necessary to forge the purine ring from amino acid precursors, rendering them dependent on the uptake and interconversion of host purines. This dependency renders analogues of purines and corresponding nucleosides an interesting source of potential anti-T. brucei agents. In this study, we synthesized and evaluated a series of 7-substituted 7-deazainosine derivatives and found that 6-O-alkylated analogues in particular showed highly promising in vitro activity with EC50 values in the mid-nanomolar range. SAR investigation of the O-alkyl chain showed that antitrypanosomal activity increased, and also cytotoxicity, with alkyl chain length, at least in the linear alkyl chain series. However, this could be attenuated by introducing a terminal branch point, resulting in the highly potent and selective analogues, 36, 37 and 38. No resistance related to transporter-mediated uptake could be identified, earmarking several of these analogues for further in vivo follow-up studies.


Assuntos
Descoberta de Drogas , Inosina/análogos & derivados , Nucleosídeos/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos , Alquilação , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Inosina/síntese química , Inosina/química , Inosina/farmacologia , Estrutura Molecular , Nucleosídeos/síntese química , Nucleosídeos/química , Testes de Sensibilidade Parasitária , Relação Estrutura-Atividade , Tripanossomicidas/síntese química , Tripanossomicidas/química
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