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1.
Methods Mol Biol ; 2279: 213-223, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33683697

RESUMO

Annexin V and propidium iodide staining is widely used for determining the cellular death through apoptosis. In the presence of Ca2+ ions, annexin V has a strong binding affinity for phosphatidylserine, a membrane phospholipid that during apoptosis is translocated from the inner side of the cell membrane to its outer side. On the other hand, propidium iodide has ability for DNA binding and it can only enter into necrotic or late apoptotic cells. This chapter describes a commonly used method for detection of apoptosis in a non-small cell lung cancer cell line using annexin V and propidium iodide dye. We describe the detection of different stages of apoptosis in the A549 lung cancer cell line treated with dihydroartemisinin (DHA). This apoptosis detection method can be used to determine the efficacy of different kinds of drugs on cultured cancer cell lines.


Assuntos
Anexina A5 , Apoptose/efeitos dos fármacos , Artemisininas/farmacologia , Carcinoma Pulmonar de Células não Pequenas , Fluoresceína-5-Isotiocianato/análogos & derivados , Neoplasias Pulmonares , Propídio/química , Células A549 , Anexina A5/química , Anexina A5/metabolismo , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Fluoresceína-5-Isotiocianato/química , Fluoresceína-5-Isotiocianato/metabolismo , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia
2.
Nat Commun ; 12(1): 530, 2021 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-33483501

RESUMO

The emergence and spread of artemisinin resistance, driven by mutations in Plasmodium falciparum K13, has compromised antimalarial efficacy and threatens the global malaria elimination campaign. By applying systems-based quantitative transcriptomics, proteomics, and metabolomics to a panel of isogenic K13 mutant or wild-type P. falciparum lines, we provide evidence that K13 mutations alter multiple aspects of the parasite's intra-erythrocytic developmental program. These changes impact cell-cycle periodicity, the unfolded protein response, protein degradation, vesicular trafficking, and mitochondrial metabolism. K13-mediated artemisinin resistance in the Cambodian Cam3.II line was reversed by atovaquone, a mitochondrial electron transport chain inhibitor. These results suggest that mitochondrial processes including damage sensing and anti-oxidant properties might augment the ability of mutant K13 to protect P. falciparum against artemisinin action by helping these parasites undergo temporary quiescence and accelerated growth recovery post drug elimination.


Assuntos
Artemisininas/farmacologia , Resistência a Medicamentos/genética , Eritrócitos/metabolismo , Mutação , Plasmodium falciparum/genética , Antimaláricos/farmacologia , Atovaquona/farmacologia , Pontos de Checagem do Ciclo Celular/genética , Eritrócitos/parasitologia , Perfilação da Expressão Gênica/métodos , Humanos , Metabolômica/métodos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Modelos Genéticos , Plasmodium falciparum/metabolismo , Plasmodium falciparum/fisiologia , Proteômica/métodos , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo
3.
ACS Appl Mater Interfaces ; 13(1): 287-297, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33356111

RESUMO

Malaria is one of the deadliest infectious diseases threatening half of the world population. With the deterioration of the parasiticidal effect of the current antimalarials, novel approaches such as screening of more specific inhibitors and targeted delivery of drugs have been under intensive research. Herein, we prepare hollow mesoporous ferrite nanoparticles (HMFNs) of 200 nm with ferromagnetic properties using a one-pot hydrothermal reaction. A magnetically targeted drug-delivery system coloaded with artemisinin in the inner magnetite shell and heparin on the outer mesoporous shell (HMFN@ART@HEP) is developed. Specific targeting of the magnetic nanoparticles to the parasite-infected erythrocytes is achieved by the attraction between the HMFNs and hemozoin (paramagnetic), a vital metabolite of plasmodium in the erythrocytic stage. With the hemozoin production reaching the maximum during the schizont period of the parasite, HMFN@ART@HEPs are adsorbed to the infected red blood cells (iRBCs), which not only interferes with the release of merozoites but also significantly enhances the inhibitory efficacy due to the increased local concentration of artemisinin. Subsequently, the heparin coated on the surface of the nanoparticles can efficiently interfere with the invasion of freshly released merozoites to new RBCs through the specific interaction between the parasite-derived ligands and heparin, which further increases the inhibitory effect on malaria. As a cluster of heparin, heparin-coated nanoparticles provide stronger blocking capability than free heparin, resulting from multivalent interactions with surface receptors on merozoite. Thus, we have developed a HMFN-based delivery system with considerable antimalarial efficacy, which is a promising platform for treatment against malaria.


Assuntos
Antimaláricos/farmacologia , Artemisininas/farmacologia , Heparina/farmacologia , Nanopartículas de Magnetita/química , Adsorção , Células Hep G2 , Heparina/química , Heparina/toxicidade , Humanos , Nanopartículas de Magnetita/toxicidade , Merozoítos/química , Merozoítos/efeitos dos fármacos , Testes de Sensibilidade Parasitária , Plasmodium falciparum/química , Plasmodium falciparum/efeitos dos fármacos , Porosidade
4.
Proc Natl Acad Sci U S A ; 117(52): 33235-33245, 2020 12 29.
Artigo em Inglês | MEDLINE | ID: mdl-33318193

RESUMO

The antimalarial artemisinins have also been implicated in the regulation of various cellular pathways including immunomodulation of cancers and regulation of pancreatic cell signaling in mammals. Despite their widespread application, the cellular specificities and molecular mechanisms of target recognition by artemisinins remain poorly characterized. We recently demonstrated how these drugs modulate inhibitory postsynaptic signaling by direct binding to the postsynaptic scaffolding protein gephyrin. Here, we report the crystal structure of the central metabolic enzyme pyridoxal kinase (PDXK), which catalyzes the production of the active form of vitamin B6 (also known as pyridoxal 5'-phosphate [PLP]), in complex with artesunate at 2.4-Šresolution. Partially overlapping binding of artemisinins with the substrate pyridoxal inhibits PLP biosynthesis as demonstrated by kinetic measurements. Electrophysiological recordings from hippocampal slices and activity measurements of glutamic acid decarboxylase (GAD), a PLP-dependent enzyme synthesizing the neurotransmitter γ-aminobutyric acid (GABA), define how artemisinins also interfere presynaptically with GABAergic signaling. Our data provide a comprehensive picture of artemisinin-induced effects on inhibitory signaling in the brain.


Assuntos
Artemisininas/farmacologia , Regulação para Baixo , Inibição Neural/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Piridoxal Quinase/antagonistas & inibidores , Transmissão Sináptica/efeitos dos fármacos , Trifosfato de Adenosina/análogos & derivados , Trifosfato de Adenosina/metabolismo , Animais , Artemisininas/química , Sítios de Ligação , Regulação para Baixo/efeitos dos fármacos , Fenômenos Eletrofisiológicos/efeitos dos fármacos , Feminino , Neurônios GABAérgicos/efeitos dos fármacos , Neurônios GABAérgicos/metabolismo , Glutamato Descarboxilase/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Modelos Biológicos , Modelos Moleculares , Inibidores de Proteínas Quinases/química , Piridoxal Quinase/química , Piridoxal Quinase/metabolismo , Sinapses/efeitos dos fármacos , Sinapses/metabolismo , Ácido gama-Aminobutírico/biossíntese
5.
PLoS Genet ; 16(12): e1009266, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33370279

RESUMO

Malaria continues to impose a significant health burden in the continent of Africa with 213 million cases in 2018 alone, representing 93% of cases worldwide. Because of high transmission of malaria within the continent, the selection pressures to develop drug resistance in African parasites are distinct compared to the rest of the world. In light of the spread of resistance to artemisinin conferred by the C580Y mutation in the PfKelch13 propeller domain in Southeast Asia, and its independent emergence in South America, it is important to study genetic determinants of resistance in the African context using African parasites. Through in vitro evolution of Senegalese parasites, we had previously generated the artemisinin-resistant parasites Pikine_R and Thiès_R and established pfcoronin mutations to be sufficient to confer artemisinin resistance in the standard ring-stage survival assay (RSA). In the current study, we used genetic analysis of revertants to demonstrate pfcoronin to be the major driver of elevated RSA in the artemisinin-resistant parasites Pikine_R and Thiès_R evolved in vitro. We interrogated the role of a second gene PF3D7_1433800, which also had mutations in both the Pikine_R and Thiès_R selected lines, but found no evidence of a contribution to reduced susceptibility in the RSA survival assay. Nevertheless, our genetic analysis demonstrates that parasite genetic background is important in the level of pfcoronin mediated RSA survival, and therefore we cannot rule out a role for PF3D7_1433800 in other genetic backgrounds. Finally, we tested the potential synergy between the mutations of pfcoronin and pfkelch13 through the generation of single and double mutants in the Pikine genetic background and found that the contribution of pfcoronin to reduced susceptibility is masked by the presence of pfkelch13. This phenomenon was also observed in the 3D7 background, suggesting that pfcoronin may mediate its effects via the same pathway as pfkelch13. Investigating the biology of proteins containing the beta-propeller domain could further elucidate the different pathways that the parasite could use to attain resistance.


Assuntos
Resistência a Medicamentos , Patrimônio Genético , Proteínas dos Microfilamentos/genética , Mutação , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Antimaláricos/farmacologia , Artemisininas/farmacologia , Repetição Kelch , Proteínas dos Microfilamentos/química , Plasmodium falciparum/efeitos dos fármacos , Proteínas de Protozoários/química
6.
Ann Parasitol ; 63(3): 295-302, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33128446

RESUMO

Visceral leishmaniosis is one of the most fatal old-world neglected disease with estimated 90 thousand worldwide cases emerge each year. In Iraq, the cutaneous and visceral form are endemic but available chemotherapies are either toxic with diverse side effects, expensive available drugs or parasite resistant is arising. Artemisinin (ART) is a semi-synthetic compound which proved its effectiveness against protozoan parasites, such as malaria and Leishmania. In this study, the efficacy of different concentrations of pure artemisinin was screened in vitro against promastigotes and axenic amastigotes by MTT assay after 24, 48 and 27 hours follow up. In addition, the infectivity ability and number was investigated of intra-cellular Leishman bodies in treated murine peritoneal macrophages after 24 and 48 hours ART treatment. The results verified ART efficacy against the promastigotes and axenic amastigotes viability with IC50 measured after 24, 48- and 72-hours treatment. Infectivity percentage of murine macrophages and parasite burden were significantly reduced in treated cells. These findings indicate the leishmanicidal activity of ART against the Iraqi isolate of L. donovani and further in vivo study is recommended for assigning ART as a natural anti visceral leishmaniosis compound.


Assuntos
Antiprotozoários , Artemisininas , Leishmania donovani , Leishmaniose Visceral , Animais , Antiprotozoários/farmacologia , Antiprotozoários/uso terapêutico , Artemisininas/farmacologia , Artemisininas/uso terapêutico , Iraque , Leishmaniose Visceral/tratamento farmacológico , Macrófagos , Camundongos
7.
Nat Commun ; 11(1): 4813, 2020 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-32968076

RESUMO

Artemisinins have revolutionized the treatment of Plasmodium falciparum malaria; however, resistance threatens to undermine global control efforts. To broadly explore artemisinin susceptibility in apicomplexan parasites, we employ genome-scale CRISPR screens recently developed for Toxoplasma gondii to discover sensitizing and desensitizing mutations. Using a sublethal concentration of dihydroartemisinin (DHA), we uncover the putative transporter Tmem14c whose disruption increases DHA susceptibility. Screens performed under high doses of DHA provide evidence that mitochondrial metabolism can modulate resistance. We show that disrupting a top candidate from the screens, the mitochondrial protease DegP2, lowers porphyrin levels and decreases DHA susceptibility, without significantly altering parasite fitness in culture. Deleting the homologous gene in P. falciparum, PfDegP, similarly lowers heme levels and DHA susceptibility. These results expose the vulnerability of heme metabolism to genetic perturbations that can lead to increased survival in the presence of DHA.


Assuntos
Antimaláricos/farmacologia , Artemisininas/farmacologia , Resistência a Medicamentos/genética , Testes Genéticos/métodos , Heme/genética , Heme/metabolismo , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Técnicas de Inativação de Genes , Humanos , Malária Falciparum/tratamento farmacológico , Proteínas de Membrana Transportadoras/metabolismo , Mutação , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Toxoplasma/efeitos dos fármacos , Toxoplasma/genética
8.
PLoS Med ; 17(8): e1003203, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32822347

RESUMO

BACKGROUND: Artemisinin resistance is threatening malaria control. We aimed to develop and test a human model of artemisinin-resistant (ART-R) Plasmodium falciparum to evaluate the efficacy of drugs against ART-R malaria. METHODS AND FINDINGS: We conducted 2 sequential phase 1, single-centre, open-label clinical trials at Q-Pharm, Brisbane, Australia, using the induced blood-stage malaria (IBSM) model, whereby healthy participants are intravenously inoculated with blood-stage parasites. In a pilot study, participants were inoculated (Day 0) with approximately 2,800 viable P. falciparum ART-R parasites. In a comparative study, participants were randomised to receive approximately 2,800 viable P. falciparum ART-R (Day 0) or artemisinin-sensitive (ART-S) parasites (Day 1). In both studies, participants were administered a single approximately 2 mg/kg oral dose of artesunate (AS; Day 9). Primary outcomes were safety, ART-R parasite infectivity, and parasite clearance. In the pilot study, 2 participants were enrolled between April 27, 2017, and September 12, 2017, and included in final analyses (males n = 2 [100%], mean age = 26 years [range, 23-28 years]). In the comparative study, 25 participants were enrolled between October 26, 2017, and October 18, 2018, of whom 22 were inoculated and included in final analyses (ART-R infected participants: males n = 7 [53.8%], median age = 22 years [range, 18-40 years]; ART-S infected participants: males n = 5 [55.6%], median age = 28 years [range, 22-35 years]). In both studies, all participants inoculated with ART-R parasites became parasitaemic. A total of 36 adverse events were reported in the pilot study and 277 in the comparative study. Common adverse events in both studies included headache, pyrexia, myalgia, nausea, and chills; none were serious. Seven participants experienced transient severe falls in white cell counts and/or elevations in liver transaminase levels which were considered related to malaria. Additionally, 2 participants developed ventricular extrasystoles that were attributed to unmasking of a predisposition to benign fever-induced tachyarrhythmia. In the comparative study, parasite clearance half-life after AS was significantly longer for ART-R infected participants (n = 13, 6.5 hours; 95% confidence interval [CI] 6.3-6.7 hours) compared with ART-S infected participants (n = 9, 3.2 hours; 95% CI 3.0-3.3 hours; p < 0.001). The main limitation of this study was that the ART-R and ART-S parasite strains did not share the same genetic background. CONCLUSIONS: We developed the first (to our knowledge) human model of ART-R malaria. The delayed clearance profile of ART-R parasites after AS aligns with field study observations. Although based on a relatively small sample size, results indicate that this model can be safely used to assess new drugs against ART-R P. falciparum. TRIAL REGISTRATION: The studies were registered with the Australian New Zealand Clinical Trials Registry: ACTRN12617000244303 (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=372357) and ACTRN12617001394336 (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373637).


Assuntos
Anti-Infecciosos/uso terapêutico , Antimaláricos/uso terapêutico , Artemisininas/uso terapêutico , Malária Falciparum/sangue , Malária Falciparum/tratamento farmacológico , Plasmodium falciparum/metabolismo , Adolescente , Adulto , Animais , Anti-Infecciosos/efeitos adversos , Anti-Infecciosos/farmacologia , Antimaláricos/efeitos adversos , Antimaláricos/farmacologia , Artemisininas/efeitos adversos , Artemisininas/farmacologia , Artesunato/efeitos adversos , Artesunato/farmacologia , Artesunato/uso terapêutico , Austrália/epidemiologia , Feminino , Cefaleia/induzido quimicamente , Voluntários Saudáveis , Humanos , Malária Falciparum/epidemiologia , Masculino , Náusea/induzido quimicamente , Parasitos/metabolismo , Projetos Piloto , Adulto Jovem
9.
PLoS One ; 15(8): e0237791, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32822392

RESUMO

Artemisinin-based combination therapies (ACTs) have been recommended by the World Health Organization (WHO) as first-line treatment of uncomplicated Plasmodium falciparum (P. falciparum) malaria since 2005 in Democratic Republic of Congo (DRC) and a regular surveillance of the ACT efficacy is required to ensure the treatment effectiveness. Mutations in the propeller domain of the pfk13 gene were identified as molecular markers of artemisinin resistance (ART-R). This study investigated the pfk13-propeller gene polymorphism in clinical isolates of P. falciparum collected in the DRC. In 2017, ten geographical sites across DRC were selected for a cross-sectional study that was conducted first in Kinshasa from January to March, then in the nine other sites from September to December. Dried blood samples were collected from patients attending health centers for fever where diagnosis of Malaria was first made by rapid diagnostic test (RDT) available on site (SD Bioline malaria Ag Pf or CareStart Malaria Pf) or by thick blood smear and then confirmed by a P. falciparum real-time PCR assay. A pfk13-propeller segment containing a fragment that codes for amino acids at positions 427-595 was amplified by conventional PCR before sequencing. In total, 1070 patients were enrolled in the study. Real-time PCR performed confirmed the initial diagnosis of P. falciparum infection in 806 samples (75.3%; 95% CI: 72.6%- 77.9%). Of the 717 successfully sequenced P. falciparum isolates, 710 (99.0%; 95% CI: 97.9% - 99.6) were wild-type genotypes and 7 (1.0%; 95% CI: 0.4% - 2.1%) carried non-synonymous (NS) mutations in pfk13-propeller including 2 mutations (A578S and V534A) previously detected and 2 other (M472I and A569T) not yet detected in the DRC. Mutations associated with ART-R in Southeast Asia were not observed in DRC. However, the presence of other mutations in pfk13-propeller gene calls for further investigations to assess their implication in drug resistance.


Assuntos
Antimaláricos/uso terapêutico , Artemisininas/uso terapêutico , Malária Falciparum/tratamento farmacológico , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/genética , Adolescente , Adulto , Idoso , Antimaláricos/farmacologia , Artemisininas/farmacologia , Criança , Pré-Escolar , República Democrática do Congo/epidemiologia , Resistência a Medicamentos , Feminino , Humanos , Malária Falciparum/parasitologia , Masculino , Pessoa de Meia-Idade , Mutação , Polimorfismo Genético , Adulto Jovem
10.
ACS Infect Dis ; 6(9): 2524-2531, 2020 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-32786284

RESUMO

The discovery of novel drug candidates with anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) potential is critical for the control of the global COVID-19 pandemic. Artemisinin, an old antimalarial drug derived from Chinese herbs, has saved millions of lives. Artemisinins are a cluster of artemisinin-related drugs developed for the treatment of malaria and have been reported to have multiple pharmacological activities, including anticancer, antiviral, and immune modulation. Considering the reported broad-spectrum antiviral potential of artemisinins, researchers are interested in whether they could be used to combat COVID-19. We systematically evaluated the anti-SARS-CoV-2 activities of nine artemisinin-related compounds in vitro and carried out a time-of-drug-addition assay to explore their antiviral mode of action. Finally, a pharmacokinetic prediction model was established to predict the therapeutic potential of selected compounds against COVID-19. Arteannuin B showed the highest anti-SARS-CoV-2 potential with an EC50 of 10.28 ± 1.12 µM. Artesunate and dihydroartemisinin showed similar EC50 values of 12.98 ± 5.30 µM and 13.31 ± 1.24 µM, respectively, which could be clinically achieved in plasma after intravenous administration. Interestingly, although an EC50 of 23.17 ± 3.22 µM was not prominent among the tested compounds, lumefantrine showed therapeutic promise due to high plasma and lung drug concentrations after multiple dosing. Further mode of action analysis revealed that arteannuin B and lumefantrine acted at the post-entry step of SARS-CoV-2 infection. This research highlights the anti-SARS-CoV-2 potential of artemisinins and provides leading candidates for anti-SARS-CoV-2 drug research and development.


Assuntos
Antivirais/farmacologia , Artemisininas/farmacologia , Betacoronavirus/efeitos dos fármacos , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/virologia , Pneumonia Viral/tratamento farmacológico , Pneumonia Viral/virologia , Animais , Antimaláricos/farmacologia , Chlorocebus aethiops , Descoberta de Drogas , Reposicionamento de Medicamentos , Medicamentos de Ervas Chinesas/farmacologia , Pandemias , Células Vero
11.
Int J Infect Dis ; 99: 437-440, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32805422

RESUMO

OBJECTIVES: At the end of November 2019, a novel coronavirus responsible for respiratory tract infections (COVID-19) emerged in China. Despite drastic containment measures, this virus, known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), spread in Asia and Europe. The pandemic is ongoing with a particular hotspot in Southern Europe and America; many studies predicted a similar epidemic in Africa, as is currently seen in Europe and the United States of America. However, reported data have not confirmed these predictions. One of the hypotheses that could explain the later emergence and spread of COVID-19 pandemic in African countries is the use of antimalarial drugs to treat malaria, and specifically, artemisinin-based combination therapy (ACT). METHODS: The antiviral activity of fixed concentrations of ACT at concentrations consistent with those observed in human plasma when ACT is administered at oral doses for uncomplicated malaria treatment was evaluatedin vitro against a clinically isolated SARS-CoV-2 strain (IHUMI-3) in Vero E6 cells. RESULTS: Mefloquine-artesunate exerted the highest antiviral activity with % inhibition of 72.1 ± 18.3 % at expected maximum blood concentration (Cmax) for each ACT drug at doses commonly administered in malaria treatment. All the other combinations, artesunate-amodiaquine, artemether-lumefantrine, artesunate-pyronaridine, or dihydroartemisinin-piperaquine, showed antiviral inhibition in the same ranges (27.1 to 34.1 %). CONCLUSIONS: Antimalarial drugs for which concentration data in the lungs are available are concentrated from 10 to 160 fold more in the lungs than in blood. Thesein vitro results reinforce the hypothesis that antimalarial drugs could be effective as an anti-COVID-19 treatment.


Assuntos
Amodiaquina/uso terapêutico , Antimaláricos/uso terapêutico , Combinação Arteméter e Lumefantrina/uso terapêutico , Artemisininas/uso terapêutico , Betacoronavirus/efeitos dos fármacos , Infecções por Coronavirus/tratamento farmacológico , Mefloquina/uso terapêutico , Pneumonia Viral/tratamento farmacológico , Replicação Viral/efeitos dos fármacos , Amodiaquina/farmacologia , Animais , Antimaláricos/farmacologia , Combinação Arteméter e Lumefantrina/farmacologia , Artemisininas/farmacologia , Chlorocebus aethiops , Combinação de Medicamentos , Humanos , Malária/epidemiologia , Malária Falciparum/tratamento farmacológico , Mefloquina/farmacologia , Pandemias , Células Vero
12.
Trends Parasitol ; 36(11): 884-887, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32771284

RESUMO

Resistance to the artemisinin derivatives, our most effective antimalarial drugs, has not manifest as a classical resistance phenotype in which parasites can tolerate higher drug concentrations. Instead, resistant parasites have an altered maturation. We hypothesize that the short half-life of artemisinin concentrations is an unanticipated driver of this novel resistance phenotype.


Assuntos
Artemisininas/farmacologia , Resistência a Medicamentos , Plasmodium/efeitos dos fármacos , Seleção Genética/efeitos dos fármacos , Animais , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Artemisininas/uso terapêutico , Humanos , Concentração Inibidora 50
13.
Int J Nanomedicine ; 15: 4591-4606, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32612358

RESUMO

Objective: Artemisinin (ART) is a natural anti-malarial sesquiterpene lactone which has the ability to treat and activate the CLRN1 pathway to play a pivotal role in hearing loss and hair cell function. To investigate the therapeutic effect of ART in hearing loss induced by gentamicin (GM), an ART-loaded poly(ethylene glycol)-b-poly(ε-caprolactone) mPEG-PCL nanoparticle-based photosensitive hydrogel was developed and tested in this study. Materials and Methods: Artemisinin-loaded mPEG-PCL nanoparticles (mPEG-PCL-ART-NPs) were prepared by a double emulsion method and the formulation was optimized by an orthogonal experimental design. The particle size, zeta potential, morphology and in vitro dissolution of the mPEG-PCL-ART-NPs were well characterized. Biocompatibility of the mPEG-PCL-ART-NPs were tested on HeLa cells with an MTT assay. The photo-crosslinkable biodegradable gelatin methacrylate (GelMA) hydrogel was prepared and its physicochemical properties (such as substitution, photocrosslinking efficiency, cell viability morphology, mechanical and swelling properties) were evaluated. Finally, mPEG-PCL-ART-FITC-NPs, loaded mPEG-PCL-ART-NPs, and loaded mPEG-PCL-ART-NPs-GelMA hydrogels were fabricated and a GM toxicity-induced guinea pig ear damage model was established to determine the effectiveness of the materials on returning auditory function and cochlea pathomorphology. Results: The zeta potential of the mPEG-PCL-ART-NPs was about -38.64 ± 0.21 mV and the average size was 167.51 ± 1.87 nm with an encapsulation efficacy of 81.7 ± 1.46%. In vitro release studies showed that the mPEG-PCL-ART-NPs possessed a sustained-release effect and the MTT experiments showed good biocompatibility properties of the drug-loaded nanoparticles. The results indicated that the 5% GelMA with MA-4% hydrogel had a better crosslinking density and 3D structure for drug loading and drug delivery than controls. Skin penetration results showed that the mPEG-PCL-ART-NPs increased adhesive capacity and avoided fast diffusion in the skin. Most importantly, auditory brainstem response results indicated that the mPEG-PCL-ART-NPs-GelMA hydrogel alleviated hearing loss induced by GM. Conclusion: These results suggested that the presently fabricated mPEG-PCL-ART-NPs-GelMA hydrogels are promising formulations for the treatment of hearing loss induced by GM and lay the foundation for further clinical research of inner ear induction therapy.


Assuntos
Artemisininas/administração & dosagem , Artemisininas/farmacologia , Gentamicinas/efeitos adversos , Perda Auditiva/tratamento farmacológico , Hidrogéis/administração & dosagem , Animais , Artemisininas/farmacocinética , Sistemas de Liberação de Medicamentos , Etilenoglicóis/química , Gelatina , Cobaias , Células HeLa , Perda Auditiva/induzido quimicamente , Humanos , Hidrogéis/química , Metacrilatos/química , Nanopartículas/química , Tamanho da Partícula , Poliésteres/química , Polietilenoglicóis/química
14.
Am J Trop Med Hyg ; 103(3): 1100-1106, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32588794

RESUMO

The emergence and spread of resistance in Plasmodium falciparum to the frontline treatment artemisinin-based combination therapies in Southeast Asia require close monitoring of the situation. Here, we collected 36 clinical samples of P. falciparum from the China-Myanmar border in 2014-2016, adapted these parasites to continuous culture, and performed in vitro drug assays on seven antimalarial drugs. Data for 23 parasites collected in 2010 and 2012 from the same area reported in an early study were used to assess longitudinal changes in drug sensitivity. Parasites remained highly resistant to chloroquine (CQ) and pyrimethamine, whereas they were generally sensitive to mefloquine (MFQ), lumefantrine (LMF), naphthoquine (NQ), and pyronaridine (PND). Parasites showed a similar temporal trend in sensitivity to CQ, NQ, and PND, with gradual reduction in the half-maximal inhibitory concentrations (IC50s) after 2012. The IC50s to the aminoalcohol drugs MFQ, LMF, and quinine (QN) all significantly declined in 2014, followed by various degrees of increase in 2016. Pyrimethamine displayed a continuous increase in IC50 over the years. The Dd2-like P. falciparum chloroquine-resistant transporter mutations were fixed or nearly fixed in the parasite population. The P. falciparum multidrug resistance 1 F1226Y mutation was detected in 80% parasites in 2016 and associated with reduced sensitivity to LMF and QN (P < 0.05). The N51I in P. falciparum dihydrofolate reductase and K540E/N and A581G in P. falciparum dihydropteroate synthase that are associated with antifolate resistance were either fixed or were approaching fixation in recent years. This study provides an updated picture and temporal trend of antimalarial drug resistance in the China-Myanmar border region, which will serve as a reference for antimalarial treatment.


Assuntos
Antimaláricos/farmacologia , Resistência a Medicamentos/genética , Malária Falciparum/parasitologia , Plasmodium falciparum/genética , Artemisininas/farmacologia , China/epidemiologia , Cloroquina/farmacologia , Monitoramento Epidemiológico , Humanos , Lumefantrina/farmacologia , Malária Falciparum/tratamento farmacológico , Malária Falciparum/epidemiologia , Mefloquina/farmacologia , Proteínas de Membrana Transportadoras/genética , Mianmar/epidemiologia , Testes de Sensibilidade Parasitária , Plasmodium falciparum/efeitos dos fármacos , Pirimetamina/farmacologia , Quinina/farmacologia
15.
Trends Parasitol ; 36(9): 735-744, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32586776

RESUMO

Artemisinin and its derivatives (ART) are crucial first-line antimalarial drugs that rapidly clear parasitemia, but recrudescences of the infection frequently follow ART monotherapy. For this reason, ART must be used in combination with one or more partner drugs that ensure complete cure. The ability of malaria parasites to survive ART monotherapy may relate to an innate growth bistability phenomenon whereby a fraction of the drug-exposed population enters into metabolic quiescence (dormancy) as persister forms. Characterization of the events that underlie entry and waking from persistence may lead to lasting breakthroughs in malaria chemotherapy that can prevent recrudescences and protect the future of ART-based combination therapies.


Assuntos
Artemisininas/farmacologia , Resistência a Medicamentos , Plasmodium/efeitos dos fármacos , Antimaláricos/farmacologia , Humanos , Recidiva
16.
Life Sci ; 256: 117966, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32535079

RESUMO

AIM: The present study aims to investigate the protective effects of artemisinin (ATZ) on early renal damage in experimental diabetic rats and its probable mechanism. METHODS: Models of diabetic nephropathy (DN) rats was established utilizing streptozotocin (STZ)-injection intraperitoneally (55 mg/kg) method. All rats were subsequently divided into normal control group, model group and ATZ (25, 50, 75 mg/kg) group randomly. Biochemical parameters including body weight, kidney index, blood glucose, 24 h UAER, Scr, BUN, T-SOD, GSH-Px and MDA were comprehensively determined after 8-week consecutive administrations. HE and PAS stainings were performed to observe the histopathological alterations of kidney. Western blot was conducted to detect the expressions of TGF-ß1, Nrf2, HQ-1 and NQO1. KEY FINDINGS: ATZ at three concentrations in ATZ group significantly increased the body weight. Biochemical parameters altered significantly between model group and ATZ group. Moreover, ATZ inhibited TGF-ß1 protein expression and activated the Nrf2 signaling pathway. Pathological histology results revealed the alterations including mesangial cells proliferation, thickness of glomerular capillary basement membrane, extracellular matrix (ECM) and the 24 h UAER. Western blot analysis demonstrated the increase of antioxidant proteins HO-1 and NQO1 and Nrf2-related proteins. SIGNIFICANCE: ATZ could reduce early renal oxidative stress damage in DN rats by inhibiting TGF-ß1 protein expression in kidney tissues as well as activating the Nrf2 signaling pathway and enhancing the expression of antioxidant proteins, thereby exerting the protective effects on DN kidney. The current study is the first report of ATZ on attenuating effects on kidney of DN rats, which could lay solid theoretical foundations on clinical application of ATZ to treat DN.


Assuntos
Artemisininas/uso terapêutico , Nefropatias Diabéticas/tratamento farmacológico , Rim/patologia , Fator 2 Relacionado a NF-E2/metabolismo , Transdução de Sinais , Fator de Crescimento Transformador beta1/metabolismo , Animais , Artemisininas/farmacologia , Glicemia/metabolismo , Nitrogênio da Ureia Sanguínea , Peso Corporal/efeitos dos fármacos , Creatinina/sangue , Nefropatias Diabéticas/sangue , Heme Oxigenase-1/metabolismo , Rim/efeitos dos fármacos , Masculino , NAD(P)H Desidrogenase (Quinona)/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos
17.
Medicine (Baltimore) ; 99(20): e20290, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32443376

RESUMO

BACKGROUND: This study will examine the effects of artemisinin on proliferation and apoptosis of human liver cancer HepG2 cells (HLCHG-2C). METHODS: This study will systematically retrieve potential literatures in MEDLINE, Scopus, Web of Science, Cochrane Library, EMBASE, WANGFANG, and China National Knowledge Infrastructure from their initiation to the February 29, 2020. There are not limitations related to the language and publication time. All case-controlled studies (CCSs) or randomized controlled studies (RCSs) will be included in this study which investigated the effects of artemisinin on proliferation and apoptosis of HLCHG-2C. Two independent investigators will examine searched records, collect data from included studies, and will identify their methodological quality. Any divergences will be disentangled by discussion with another investigator. RevMan 5.3 software will be placed to pool the data and to carry out data analysis. RESULTS: This study will summarize all eligible studies to test the effects of artemisinin on proliferation and apoptosis of HLCHG-2C. CONCLUSION: The results of this study will exert evidence to examine the effects of artemisinin on proliferation and apoptosis of HLCHG-2C, and it may benefit further research, patients, and healthcare providers. SYSTEMATIC REVIEW REGISTRATION: INPLASY202040075.


Assuntos
Anti-Infecciosos/farmacologia , Apoptose/efeitos dos fármacos , Artemisininas/farmacologia , Proliferação de Células/efeitos dos fármacos , Neoplasias Hepáticas/tratamento farmacológico , Células Hep G2 , Humanos , Projetos de Pesquisa
18.
Trends Parasitol ; 36(6): 533-544, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32359872

RESUMO

Artemisinins - the frontline antimalarial drug class - are compromised by emerging resistance, putting at risk the lives of hundreds of thousands of people each year. Resistance is associated with mutations in a malaria parasite protein, called Kelch 13 (K13). Recent work suggests that K13 is located at the cytostome (cell mouth) that the parasite uses to take up hemoglobin. Here we explore the proposal that K13 mutations confer artemisinin resistance by dampening hemoglobin endocytosis. This model suggests that the resultant decrease in hemoglobin-derived heme reduces artemisinin activation, which is sufficient to enable parasite survival in the early ring stage of infection. A fuller understanding of the resistance mechanism will underpin efforts to develop alternative antimalarial strategies.


Assuntos
Artemisininas/farmacologia , Resistência a Medicamentos/genética , Plasmodium/efeitos dos fármacos , Plasmodium/genética , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Antimaláricos/farmacologia , Heme/metabolismo , Humanos , Mutação , Plasmodium/metabolismo
19.
Trends Parasitol ; 36(6): 520-532, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32340866

RESUMO

Endocytosis is critical for many functions in eukaryotic cells. Uptake of host cell cytosol, an indispensable endocytic process in malaria blood-stage parasites, has been known for a long time. However, it is only recently that the proteins involved in this process have started to emerge. Unexpectedly, some of these proteins revealed a critical role for endocytosis in artemisinin resistance. More recently, endocytosis was discovered in both intracellular and extracellular Toxoplasma gondii parasites. Here, we review these findings, compare the endolysosomal systems of Toxoplasma and Plasmodium parasites, and present current knowledge about endocytic mechanisms in apicomplexans.


Assuntos
Endocitose/fisiologia , Plasmodium/fisiologia , Toxoplasma/fisiologia , Animais , Antiparasitários/farmacologia , Artemisininas/farmacologia , Resistência a Medicamentos , Humanos , Plasmodium/efeitos dos fármacos , Toxoplasma/efeitos dos fármacos
20.
PLoS Pathog ; 16(4): e1008482, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32310999

RESUMO

The emergence of artemisinin (ART) resistance in Plasmodium falciparum intra-erythrocytic parasites has led to increasing treatment failure rates with first-line ART-based combination therapies in Southeast Asia. Decreased parasite susceptibility is caused by K13 mutations, which are associated clinically with delayed parasite clearance in patients and in vitro with an enhanced ability of ring-stage parasites to survive brief exposure to the active ART metabolite dihydroartemisinin. Herein, we describe a panel of K13-specific monoclonal antibodies and gene-edited parasite lines co-expressing epitope-tagged versions of K13 in trans. By applying an analytical quantitative imaging pipeline, we localize K13 to the parasite endoplasmic reticulum, Rab-positive vesicles, and sites adjacent to cytostomes. These latter structures form at the parasite plasma membrane and traffic hemoglobin to the digestive vacuole wherein artemisinin-activating heme moieties are released. We also provide evidence of K13 partially localizing near the parasite mitochondria upon treatment with dihydroartemisinin. Immunoprecipitation data generated with K13-specific monoclonal antibodies identify multiple putative K13-associated proteins, including endoplasmic reticulum-resident molecules, mitochondrial proteins, and Rab GTPases, in both K13 mutant and wild-type isogenic lines. We also find that mutant K13-mediated resistance is reversed upon co-expression of wild-type or mutant K13. These data help define the biological properties of K13 and its role in mediating P. falciparum resistance to ART treatment.


Assuntos
Resistência a Medicamentos/genética , Plasmodium falciparum/genética , Antimaláricos/farmacologia , Artemisininas/farmacologia , Resistência a Medicamentos/fisiologia , Humanos , Malária Falciparum/parasitologia , Mutação , Plasmodium falciparum/metabolismo , Proteínas de Protozoários/metabolismo
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