Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 315
Filtrar
1.
Nat Commun ; 12(1): 4878, 2021 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-34385447

RESUMO

A postprandial increase of translation mediated by eukaryotic Initiation Factor 6 (eIF6) occurs in the liver. Its contribution to steatosis and disease is unknown. In this study we address whether eIF6-driven translation contributes to disease progression. eIF6 levels increase throughout the progression from Non-Alcoholic Fatty Liver Disease (NAFLD) to hepatocellular carcinoma. Reduction of eIF6 levels protects the liver from disease progression. eIF6 depletion blunts lipid accumulation, increases fatty acid oxidation (FAO) and reduces oncogenic transformation in vitro. In addition, eIF6 depletion delays the progression from NAFLD to hepatocellular carcinoma, in vivo. Mechanistically, eIF6 depletion reduces the translation of transcription factor C/EBPß, leading to a drop in biomarkers associated with NAFLD progression to hepatocellular carcinoma and preserves mitochondrial respiration due to the maintenance of an alternative mTORC1-eIF4F translational branch that increases the expression of transcription factor YY1. We provide proof-of-concept that in vitro pharmacological inhibition of eIF6 activity recapitulates the protective effects of eIF6 depletion. We hypothesize the existence of a targetable, evolutionarily conserved translation circuit optimized for lipid accumulation and tumor progression.


Assuntos
Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , Hepatopatia Gordurosa não Alcoólica/genética , Fatores de Iniciação de Peptídeos/genética , Biossíntese de Proteínas/genética , Animais , Proteína beta Intensificadora de Ligação a CCAAT/genética , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Carcinoma Hepatocelular/metabolismo , Linhagem Celular , Transformação Celular Neoplásica/efeitos dos fármacos , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Clofazimina/farmacologia , Dieta Hiperlipídica/efeitos adversos , Progressão da Doença , Inativação Gênica , Humanos , Lipogênese/efeitos dos fármacos , Lipogênese/genética , Neoplasias Hepáticas/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica/metabolismo , Obesidade/etiologia , Obesidade/genética , Obesidade/metabolismo , Fatores de Iniciação de Peptídeos/antagonistas & inibidores , Fatores de Iniciação de Peptídeos/metabolismo
3.
Eur J Med Chem ; 222: 113562, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34116325

RESUMO

Triple-negative breast cancer (TNBC) is a cancer subtype critically dependent upon excessive activation of Wnt pathway. The anti-mycobacterial drug clofazimine is an efficient inhibitor of canonical Wnt signaling in TNBC, reducing tumor cell proliferation in vitro and in animal models. These properties make clofazimine a candidate to become first targeted therapy against TNBC. In this work, we optimized the clofazimine structure to enhance its water solubility and potency as a Wnt inhibitor. After extensive structure-activity relationships investigations, the riminophenazine 5-(4-(chlorophenyl)-3-((2-(piperazin-1-yl)ethyl)imino)-N-(pyridin-3-yl)-3,5-dihydrophenazin-2-amine (MU17) was identified as the new lead compound for the riminophenazine-based targeted therapy against TNBC and Wnt-dependent cancers. Compared to clofazimine, the water-soluble MU17 displayed a 7-fold improved potency against Wnt signaling in TNBC cells resulting in on-target suppression of tumor growth in a patient-derived mouse model of TNBC. Moreover, allowing the administration of reduced yet effective dosages, MU17 displayed no adverse effects, most notably no clofazimine-related skin coloration.


Assuntos
Clofazimina/farmacologia , Fenazinas/farmacologia , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Clofazimina/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Neoplasias Mamárias Experimentais/tratamento farmacológico , Neoplasias Mamárias Experimentais/metabolismo , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Estrutura Molecular , Fenazinas/síntese química , Fenazinas/química , Solubilidade , Relação Estrutura-Atividade , Água/química , Via de Sinalização Wnt/efeitos dos fármacos
4.
Int J Mol Sci ; 22(6)2021 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-33805837

RESUMO

For over 50 years, patients with drug-sensitive and drug-resistant tuberculosis have undergone long, arduous, and complex treatment processes with several antimicrobials. With the prevalence of drug-resistant strains on the rise and new therapies for tuberculosis urgently required, we assessed whether manipulating iron levels in macrophages infected with mycobacteria offered some insight into improving current antimicrobials that are used to treat drug-resistant tuberculosis. We investigated if the iron chelator, desferrioxamine, can support the function of human macrophages treated with an array of second-line antimicrobials, including moxifloxacin, bedaquiline, amikacin, clofazimine, linezolid and cycloserine. Primary human monocyte-derived macrophages were infected with Bacillus Calmette-Guérin (BCG), which is pyrazinamide-resistant, and concomitantly treated for 5 days with desferrioxamine in combination with each one of the second-line tuberculosis antimicrobials. Our data indicate that desferrioxamine used as an adjunctive treatment to bedaquiline significantly reduced the bacterial load in human macrophages infected with BCG. Our findings also reveal a link between enhanced bactericidal activity and increases in specific cytokines, as the addition of desferrioxamine increased levels of IFN-γ, IL-6, and IL-1ß in BCG-infected human monocyte-derived macrophages (hMDMs) treated with bedaquiline. These results provide insight, and an in vitro proof-of-concept, that iron chelators may prove an effective adjunctive therapy in combination with current tuberculosis antimicrobials.


Assuntos
Antituberculosos/farmacologia , Desferroxamina/farmacologia , Diarilquinolinas/farmacologia , Quelantes de Ferro/farmacologia , Ferro/metabolismo , Macrófagos/efeitos dos fármacos , Mycobacterium bovis/efeitos dos fármacos , Amicacina/farmacologia , Carga Bacteriana/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Clofazimina/farmacologia , Ciclosserina/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Sinergismo Farmacológico , Expressão Gênica , Humanos , Interferon gama/genética , Interferon gama/imunologia , Interleucina-1beta/genética , Interleucina-1beta/imunologia , Interleucina-6/genética , Interleucina-6/imunologia , Linezolida/farmacologia , Macrófagos/imunologia , Macrófagos/microbiologia , Testes de Sensibilidade Microbiana , Moxifloxacina/farmacologia , Mycobacterium bovis/crescimento & desenvolvimento , Mycobacterium bovis/metabolismo , Cultura Primária de Células , Pirazinamida/farmacologia
5.
Zhonghua Jie He He Hu Xi Za Zhi ; 44(3): 225-229, 2021 Mar 12.
Artigo em Chinês | MEDLINE | ID: mdl-33721936

RESUMO

Objective: To analyze the drug resistance of tuberculosis patients to clofazimine. Methods: Retrospective analysis was conducted on the case data of 1 770 tuberculosis patients in Department of tuberculosis, Beijing Chest Hospital affiliated to Capital Medical University from January 2015 to June 2018, including 1 225 males and 545 females, aged 8-92 (43.2±15.2) years old. Drug sensitivity tests using proportion method (hereinafter referred to as drug susceptibility test) for TB strains anti-tb drug resistance test. Using χ2 test or Fisher's exact test. Results: 1 770 cases of tuberculosis patients, 1 713 cases of patients with clofazimine sensitive, of 57 patients with drug resistance, and resistant rate was 3.2% (57/1 770), including patients with recurrent clofazimine, significantly higher than the initial percentages of patients [5.8% (38/656), 1.7% (19/1 114), χ²= 22.129, P = 0.000, P<0.01]; The drug resistance rates of poly-resistant, multi-drug resistant and extensively resistant patients to clofazimine were 1.0% (17/1 770), 1.2% (21/1 770) and 1.1% (19/1 770), respectively. Has a history of hospitalization of clofazimine resistance of multidrug-resistant and extensively drug-resistant patients resistant rate 2.4% (14/594), 2.7% (16/594), respectively, higher than 0.6% (7/1 176) with no history of hospitalized patients, 0.3% (3/1 176), the differences were statistically significant (χ²=10.447,22.099,P=0.001,<0.001). Conclusion: Clofazimine has a low resistance rate, which can improve the treatment success rate of patients with drug-resistant tuberculosis and has important value.


Assuntos
Mycobacterium tuberculosis , Tuberculose Resistente a Múltiplos Medicamentos , Tuberculose , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antituberculosos/farmacologia , Antituberculosos/uso terapêutico , Criança , Clofazimina/farmacologia , Clofazimina/uso terapêutico , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Estudos Retrospectivos , Tuberculose/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia , Adulto Jovem
6.
Nature ; 593(7859): 418-423, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33727703

RESUMO

The COVID-19 pandemic is the third outbreak this century of a zoonotic disease caused by a coronavirus, following the emergence of severe acute respiratory syndrome (SARS) in 20031 and Middle East respiratory syndrome (MERS) in 20122. Treatment options for coronaviruses are limited. Here we show that clofazimine-an anti-leprosy drug with a favourable safety profile3-possesses inhibitory activity against several coronaviruses, and can antagonize the replication of SARS-CoV-2 and MERS-CoV in a range of in vitro systems. We found that this molecule, which has been approved by the US Food and Drug Administration, inhibits cell fusion mediated by the viral spike glycoprotein, as well as activity of the viral helicase. Prophylactic or therapeutic administration of clofazimine in a hamster model of SARS-CoV-2 pathogenesis led to reduced viral loads in the lung and viral shedding in faeces, and also alleviated the inflammation associated with viral infection. Combinations of clofazimine and remdesivir exhibited antiviral synergy in vitro and in vivo, and restricted viral shedding from the upper respiratory tract. Clofazimine, which is orally bioavailable and comparatively cheap to manufacture, is an attractive clinical candidate for the treatment of outpatients and-when combined with remdesivir-in therapy for hospitalized patients with COVID-19, particularly in contexts in which costs are an important factor or specialized medical facilities are limited. Our data provide evidence that clofazimine may have a role in the control of the current pandemic of COVID-19 and-possibly more importantly-in dealing with coronavirus diseases that may emerge in the future.


Assuntos
Antivirais/farmacologia , Clofazimina/farmacologia , Coronavirus/classificação , Coronavirus/efeitos dos fármacos , SARS-CoV-2/efeitos dos fármacos , Monofosfato de Adenosina/análogos & derivados , Monofosfato de Adenosina/farmacologia , Monofosfato de Adenosina/uso terapêutico , Alanina/análogos & derivados , Alanina/farmacologia , Alanina/uso terapêutico , Animais , Anti-Inflamatórios/farmacocinética , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Antivirais/farmacocinética , Antivirais/uso terapêutico , Disponibilidade Biológica , Fusão Celular , Linhagem Celular , Clofazimina/farmacocinética , Clofazimina/uso terapêutico , Coronavirus/crescimento & desenvolvimento , Coronavirus/patogenicidade , Cricetinae , DNA Helicases/antagonistas & inibidores , Sinergismo Farmacológico , Feminino , Humanos , Estágios do Ciclo de Vida/efeitos dos fármacos , Masculino , Mesocricetus , Profilaxia Pré-Exposição , SARS-CoV-2/crescimento & desenvolvimento , Especificidade da Espécie , Glicoproteína da Espícula de Coronavírus/antagonistas & inibidores , Transcrição Genética/efeitos dos fármacos , Transcrição Genética/genética
7.
Int J Infect Dis ; 102: 392-396, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33130209

RESUMO

OBJECTIVES: We described the prevalence of clofazimine (CFZ) resistance in a multidrug-resistant tuberculosis (MDR-TB) cohort in China. We also aimed to identify dynamic changes in CFZ susceptibility and its molecular mechanism after exposure to bedaquiline (BDQ) and/or CFZ. METHODS: The experimental settings were conducted based on our MDR-TB cohort receiving BDQ-containing regimens. Sequential isolates were obtained from patients. CFZ and BDQ susceptibility of isolates were determined using the minimum inhibitory concentration (MIC) method. The fragments of Rv0678 and pepQ were sequenced. RESULTS: A total of 277 patients infected with MDR-TB were included in our study. CFZ resistance was noted in 23 (23/277, 8.3%) isolates. The rate of acquired CFZ resistance (12/189, 6.3%) was significantly greater than that of primary resistance (11/88, 12.5%, P = 0.028). Out of 23 CFZ-resistant isolates, five (5/23) were BDQ-resistant, and the other 18 (18/23) were susceptible to BDQ. Of note, nine 9/23) out of 23 CFZ-resistant isolates had mutations within either target genes. Kaplan-Meier analysis demonstrated that the baseline CFZ resistance had no influence on time to culture conversion in our cohort (P = 0.828). Acquired CFZ resistance emerged in eight (8/94, 8.5%) patients during treatment for MDR-TB, including three patients receiving regimens without CFZ. CONCLUSIONS: Our results demonstrate the high rate of CFZ resistance among MDR-TB patients in China. Patients treated with BDQ-containing regimens achieve comparative culture conversion rate regardless of baseline CFZ susceptibility. The presence of acquired CFZ-resistance following BDQ treatment without known mutation indicates that other mechanisms conferring cross resistance to these two compounds may exist.


Assuntos
Antituberculosos/uso terapêutico , Clofazimina/farmacologia , Diarilquinolinas/uso terapêutico , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Mycobacterium tuberculosis/efeitos dos fármacos , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , China , Estudos de Coortes , Feminino , Genótipo , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Mutação , Mycobacterium tuberculosis/genética , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia
8.
Biomed Pharmacother ; 131: 110782, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33152940

RESUMO

Multidrug-resistant tuberculosis (MDR-TB) remains a serious public health threat worldwide. To date, the anti-TB activity of TB47 (T), an imidazopyridine amide class of antibiotics targeting QcrB in the electron transport chain, has not been systematically evaluated, especially in a new regimen against MDR-TB. This study employed both macrophage infection and a mouse model to test the activity of T alone or in combination with other antimicrobial agents. Different regimens containing amikacin (A), levofloxacin (L), ethambutol (E), and pyrazinamide (Z) + clofazimine (C)/T were evaluated in the mouse model. The bacterial burdens of mice from different groups were monitored at different time points while relapse was assessed 6 months after treatment cessation. Colonies obtained at relapse underwent drug susceptibility testing. We found that T exhibited highly synergistic bactericidal activity with C in all models. Adding T to ALEZC might shorten the MDR-TB treatment duration from ≥ 9 months to ≤ 5months, as five months of treatment with ALEZCT achieved zero relapse rates in 2 animal experiments. These findings indicate that T exhibits a highly synergistic sterilizing activity when combined with C. All isolates from relapsing mice remained sensitive to each drug, suggesting that the relapse was not due to drug resistance but rather associated with the type of regimen.


Assuntos
Antituberculosos/farmacologia , Clofazimina/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Animais , Antituberculosos/administração & dosagem , Antituberculosos/química , Clofazimina/administração & dosagem , Modelos Animais de Doenças , Sinergismo Farmacológico , Feminino , Imidazóis/administração & dosagem , Imidazóis/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/isolamento & purificação , Piridinas/administração & dosagem , Piridinas/farmacologia , Recidiva , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia
11.
Int J Mol Sci ; 21(17)2020 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-32824985

RESUMO

The aim of this study is to examine the use of an inflammasome competitor as a preventative agent. Coronaviruses have zoonotic potential due to the adaptability of their S protein to bind receptors of other species, most notably demonstrated by SARS-CoV. The binding of SARS-CoV-2 to TLR (Toll-like receptor) causes the release of pro-IL-1ß, which is cleaved by caspase-1, followed by the formation and activation of the inflammasome, which is a mediator of lung inflammation, fever, and fibrosis. The NLRP3 (NACHT, LRR and PYD domains-containing protein 3) inflammasome is implicated in a variety of human diseases including Alzheimer's disease (AD), prion diseases, type 2 diabetes, and numerous infectious diseases. By examining the use of 4,4'-diaminodiphenyl sulfone (DDS) in the treatment of patients with Hansen's disease, also diagnosed as Alzheimer's disease, this study demonstrates the diverse mechanisms involved in the activation of inflammasomes. TLRs, due to genetic polymorphisms, can alter the immune response to a wide variety of microbial ligands, including viruses. In particular, TLR2Arg677Trp was reported to be exclusively present in Korean patients with lepromatous leprosy (LL). Previously, mutation of the intracellular domain of TLR2 has demonstrated its role in determining the susceptibility to LL, though LL was successfully treated using a combination of DDS with rifampicin and clofazimine. Of the three tested antibiotics, DDS was effective in the molecular regulation of NLRP3 inflammasome activators that are important in mild cognitive impairment (MCI), Parkinson's disease (PD), and AD. The specific targeting of NLRP3 itself or up-/downstream factors of the NLRP3 inflammasome by DDS may be responsible for its observed preventive effects, functioning as a competitor.


Assuntos
Infecções por Coronavirus/tratamento farmacológico , Dapsona/farmacologia , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Pneumonia Viral/tratamento farmacológico , Doença de Alzheimer/patologia , COVID-19 , Clofazimina/farmacologia , Disfunção Cognitiva/patologia , Humanos , Interleucina-1beta/metabolismo , Hanseníase/tratamento farmacológico , Hanseníase/genética , Pandemias , Transtornos Parkinsonianos/patologia , Rifampina/farmacologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Receptor 2 Toll-Like/genética
12.
PLoS Pathog ; 16(5): e1008356, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32437421

RESUMO

Tuberculosis (TB) is one of the deadliest diseases, claiming ~2 million deaths annually worldwide. The majority of people in TB endemic regions are vaccinated with Bacillus Calmette Guerin (BCG), which is the only usable vaccine available. BCG is efficacious against meningeal and disseminated TB in children, but protective responses are relatively short-lived and fail to protect against adult pulmonary TB. The longevity of vaccine efficacy critically depends on the magnitude of long-lasting central memory T (TCM) cells, a major source of which is stem cell-like memory T (TSM) cells. These TSM cells exhibit enhanced self-renewal capacity as well as to rapidly respond to antigen and generate protective poly-functional T cells producing IFN-γ, TNF-α, IL-2 and IL-17. It is now evident that T helper Th 1 and Th17 cells are essential for host protection against TB. Recent reports have indicated that Th17 cells preserve the molecular signature for TSM cells, which eventually differentiate into IFN-γ-producing effector cells. BCG is ineffective in inducing Th17 cell responses, which might explain its inadequate vaccine efficacy. Here, we show that revaccination with BCG along with clofazimine treatment promotes TSM differentiation, which continuously restores TCM and T effector memory (TEM) cells and drastically increases vaccine efficacy in BCG-primed animals. Analyses of these TSM cells revealed that they are predominantly precursors to host protective Th1 and Th17 cells. Taken together, these findings revealed that clofazimine treatment at the time of BCG revaccination provides superior host protection against TB by increasing long-lasting TSM cells.


Assuntos
Vacina BCG/imunologia , Vacina BCG/metabolismo , Clofazimina/farmacologia , Memória Imunológica/imunologia , Animais , Vacina BCG/farmacologia , Clofazimina/metabolismo , Quimioterapia Combinada/métodos , Feminino , Imunização Secundária/métodos , Imunogenicidade da Vacina/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mycobacterium bovis/imunologia , Mycobacterium tuberculosis/imunologia , Células-Tronco/imunologia , Células Th1/imunologia , Células Th17/imunologia , Tuberculose/imunologia , Tuberculose Pulmonar/imunologia
13.
J Antimicrob Chemother ; 75(8): 2031-2043, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32361756

RESUMO

BACKGROUND: Improved genetic understanding of Mycobacterium tuberculosis (MTB) resistance to novel and repurposed anti-tubercular agents can aid the development of rapid molecular diagnostics. METHODS: Adhering to PRISMA guidelines, in March 2018, we performed a systematic review of studies implicating mutations in resistance through sequencing and phenotyping before and/or after spontaneous resistance evolution, as well as allelic exchange experiments. We focused on the novel drugs bedaquiline, delamanid, pretomanid and the repurposed drugs clofazimine and linezolid. A database of 1373 diverse control MTB whole genomes, isolated from patients not exposed to these drugs, was used to further assess genotype-phenotype associations. RESULTS: Of 2112 papers, 54 met the inclusion criteria. These studies characterized 277 mutations in the genes atpE, mmpR, pepQ, Rv1979c, fgd1, fbiABC and ddn and their association with resistance to one or more of the five drugs. The most frequent mutations for bedaquiline, clofazimine, linezolid, delamanid and pretomanid resistance were atpE A63P, mmpR frameshifts at nucleotides 192-198, rplC C154R, ddn W88* and ddn S11*, respectively. Frameshifts in the mmpR homopolymer region nucleotides 192-198 were identified in 52/1373 (4%) of the control isolates without prior exposure to bedaquiline or clofazimine. Of isolates resistant to one or more of the five drugs, 59/519 (11%) lacked a mutation explaining phenotypic resistance. CONCLUSIONS: This systematic review supports the use of molecular methods for linezolid resistance detection. Resistance mechanisms involving non-essential genes show a diversity of mutations that will challenge molecular diagnosis of bedaquiline and nitroimidazole resistance. Combined phenotypic and genotypic surveillance is needed for these drugs in the short term.


Assuntos
Mycobacterium tuberculosis , Nitroimidazóis , Preparações Farmacêuticas , Tuberculose Resistente a Múltiplos Medicamentos , Antituberculosos/farmacologia , Antituberculosos/uso terapêutico , Clofazimina/farmacologia , Diarilquinolinas/farmacologia , Humanos , Linezolida/farmacologia , Testes de Sensibilidade Microbiana , Mutação , Mycobacterium tuberculosis/genética , Nitroimidazóis/farmacologia , Oxazóis , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico
14.
ACS Infect Dis ; 6(5): 1238-1249, 2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32272013

RESUMO

Drug resistant pathogens are on the rise, and new treatments are needed for bacterial infections. Efforts toward antimicrobial discovery typically identify compounds that prevent bacterial growth in microbiological media. However, the microenvironments to which pathogens are exposed during infection differ from rich media and alter the biology of the pathogen. We and others have therefore developed screening platforms that identify compounds that disrupt pathogen growth within cultured mammalian cells. Our platform focuses on Gram-negative bacterial pathogens, which are of particular clinical concern. We screened a panel of 707 drugs to identify those with efficacy against Salmonella enterica Typhimurium growth within macrophages. One of the drugs identified, clofazimine (CFZ), is an antibiotic used to treat mycobacterial infections that is not recognized for potency against Gram-negative bacteria. We demonstrated that in macrophages CFZ enabled the killing of S. Typhimurium at single digit micromolar concentrations, and in mice, CFZ reduced tissue colonization. We confirmed that CFZ does not inhibit the growth of S. Typhimurium and E. coli in standard microbiological media. However, CFZ prevents bacterial replication under conditions consistent with the microenvironment of macrophage phagosomes, in which S. Typhimurium resides during infection: low pH, low magnesium and phosphate, and the presence of certain cationic antimicrobial peptides. These observations suggest that in macrophages and mice the efficacy of CFZ against S. Typhimurium is facilitated by multiple aspects of soluble innate immunity. Thus, systematic screens of existing drugs for infection-based potency are likely to identify unexpected opportunities for repurposing drugs to treat difficult pathogens.


Assuntos
Antibacterianos/farmacologia , Clofazimina/farmacologia , Macrófagos/microbiologia , Salmonella enterica/efeitos dos fármacos , Animais , Células Cultivadas , Escherichia coli , Camundongos
15.
Biochem Pharmacol ; 177: 113993, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32339493

RESUMO

Leprosy is a chronic infectious disease caused my Mycobacterium leprae that primarily affects peripheral nervous system and extremities and is prevalent in tropical countries. Treatment for leprosy with multidrug regimens is very effective compared to monotherapy especially in multibacillary cases. The three major antileprosy drugs currently in use are 4, 4'-diaminodiphenyl sulfone (DDS, dapsone), rifampicin, and clofazimine. During multidrug therapy, the potent antibiotic rifampicin induces the metabolism of dapsone, which results in decreased plasma half-life of dapsone and its metabolites. Furthermore, rifampicin induces its own metabolism and decreases its half-life during monotherapy. Rifampicin upregulates several hepatic microsomal drug-metabolizing enzymes, especially cytochrome P450 (CYP) family that in turn induce the metabolism of dapsone. Clofazimine lacks significant induction of any drug-metabolizing enzyme including CYP family and does not interact with dapsone metabolism. Rifampicin does not induce clofazimine metabolism during combination treatment. Administration of dapsone in the acetylated form (acedapsone) can release the drug slowly into circulation up to 75 days and could be useful for the effective treatment of paucibacillary cases along with rifampicin. This review summarizes the major aspects of antileprosy drug metabolism and drug interactions and the role of cytochrome P450 family of drug metabolizing enzymes, especially CYP3A4 during multidrug regimens for the treatment of leprosy.


Assuntos
Acedapsona/sangue , Clofazimina/sangue , Citocromo P-450 CYP3A/metabolismo , Dapsona/sangue , Hansenostáticos/sangue , Hanseníase/tratamento farmacológico , Rifampina/sangue , Acedapsona/farmacocinética , Acedapsona/farmacologia , Disponibilidade Biológica , Biotransformação , Clofazimina/farmacocinética , Clofazimina/farmacologia , Dapsona/farmacocinética , Dapsona/farmacologia , Interações Medicamentosas , Quimioterapia Combinada , Meia-Vida , Humanos , Hansenostáticos/farmacocinética , Hansenostáticos/farmacologia , Hanseníase/sangue , Hanseníase/microbiologia , Hanseníase/patologia , Taxa de Depuração Metabólica , Redes e Vias Metabólicas/fisiologia , Mycobacterium leprae/efeitos dos fármacos , Mycobacterium leprae/crescimento & desenvolvimento , Mycobacterium leprae/patogenicidade , Rifampina/farmacocinética , Rifampina/farmacologia
16.
Genome Med ; 12(1): 27, 2020 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-32143680

RESUMO

BACKGROUND: A comprehensive understanding of the pre-existing genetic variation in genes associated with antibiotic resistance in the Mycobacterium tuberculosis complex (MTBC) is needed to accurately interpret whole-genome sequencing data for genotypic drug susceptibility testing (DST). METHODS: We investigated mutations in 92 genes implicated in resistance to 21 anti-tuberculosis drugs using the genomes of 405 phylogenetically diverse MTBC strains. The role of phylogenetically informative mutations was assessed by routine phenotypic DST data for the first-line drugs isoniazid, rifampicin, ethambutol, and pyrazinamide from a separate collection of over 7000 clinical strains. Selected mutations/strains were further investigated by minimum inhibitory concentration (MIC) testing. RESULTS: Out of 547 phylogenetically informative mutations identified, 138 were classified as not correlating with resistance to first-line drugs. MIC testing did not reveal a discernible impact of a Rv1979c deletion shared by M. africanum lineage 5 strains on resistance to clofazimine. Finally, we found molecular evidence that some MTBC subgroups may be hyper-susceptible to bedaquiline and clofazimine by different loss-of-function mutations affecting a drug efflux pump subunit (MmpL5). CONCLUSIONS: Our findings underline that the genetic diversity in MTBC has to be studied more systematically to inform the design of clinical trials and to define sound epidemiologic cut-off values (ECOFFs) for new and repurposed anti-tuberculosis drugs. In that regard, our comprehensive variant catalogue provides a solid basis for the interpretation of mutations in genotypic as well as in phenotypic DST assays.


Assuntos
Farmacorresistência Bacteriana , Genes MDR , Mutação , Mycobacterium tuberculosis/genética , Filogenia , Antituberculosos/farmacologia , Clofazimina/farmacologia , Diarilquinolinas/farmacologia , Concentração Inibidora 50 , Mycobacterium tuberculosis/classificação , Mycobacterium tuberculosis/efeitos dos fármacos
17.
PLoS One ; 15(2): e0228996, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32053698

RESUMO

BACKGROUND: The plenteous resistance to and undesirable consequences of the existing antipiroplasmic therapies have emphasized the urgent need for new chemotherapeutics and drug targets for both prophylaxis and chemotherapy. Hydroxyurea (HYD) is an antineoplastic agent with antitrypanosomal activity. Eflornithine (α-difluoro-methyl ornithine, DFMO) is the best choice therapy for the treatment of late-stage Gambian human African trypanosomiasis. METHODS: In this study, the inhibitory and combination efficacy of HYD and DFMO with existing babesicidal drugs (diminazene aceturate (DA), atovaquone (ATV), and clofazimine (CLF)) deoxyribonucleotide in vitro against the multiplication of Babesia and Theileria. As well as, their chemotherapeutic effects were assessed on B. microti strain that infects rodents. The Cell Counting Kits-8 (CCK-8) test was used to examine their cytotoxicity on human foreskin fibroblast (HFF), mouse embryonic fibroblast (NIH/3T3), and Madin-Darby bovine kidney (MDBK) cells. FINDINGS: HYD and DFMO suppressed the multiplication of all tested species (B. bigemina, B. bovis, B. caballi, B. divergens, and T. equi) in a dose-related manner. HFF, NIH/3T3, or MDBK cell viability was not influenced by DFMO at 1000 µM, while HYD affected the MDBK cell viability at EC50 value of 887.5±14.4 µM. The in vitro combination treatments of DFMO and HYD with CLF, DA, and ATV exhibited synergistic and additive efficacy toward all tested species. The in vivo experiment revealed that HYD and DFMO oral administration at 100 and 50 mg/kg inhibited B. microti multiplication in mice by 60.1% and 78.2%, respectively. HYD-DA and DFMO-DA combined treatments showed higher chemotherapeutic efficacy than their monotherapies. CONCLUSION: These results indicate the prospects of HYD and DFMO as drug candidates for piroplasmosis treatment, when combined mainly with DA, ATV, and CLF. Therefore, further studies are needed to combine HYD or DFMO with either ATV or CLF and examine their impact on B. microti infection in mice.


Assuntos
Babesia/efeitos dos fármacos , Eflornitina/efeitos adversos , Eflornitina/farmacologia , Hidroxiureia/efeitos adversos , Hidroxiureia/farmacologia , Theileria/efeitos dos fármacos , Animais , Antineoplásicos , Antiprotozoários/administração & dosagem , Antiprotozoários/farmacologia , Atovaquona/efeitos adversos , Atovaquona/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Clofazimina/efeitos adversos , Clofazimina/farmacologia , Diminazena/efeitos adversos , Diminazena/análogos & derivados , Diminazena/farmacologia , Cães , Prepúcio do Pênis/citologia , Humanos , Masculino , Camundongos , Células NIH 3T3
18.
Artigo em Inglês | MEDLINE | ID: mdl-32071046

RESUMO

Infections with nontuberculous mycobacteria (NTM) have a poor prognosis in patients with underlying respiratory diseases. Clofazimine (CFZ) showed both experimental and clinical promising results against clinically relevant NTM. However, there are no data on CFZ in combination with the current recommended treatment; therefore, we aimed to study its in vivo activity in an aerosol mouse model of Mycobacterium avium In an aerosol infection BALB/c mouse model using M. avium strain Chester, we treated 58 mice with four combinations of rifampin (RIF) at 10 mg/kg, CFZ at 25 mg/kg, and clarithromycin (CLR) and ethambutol (EMB) at 100 mg/kg. Treatment efficacy was assessed on the basis of lung CFU counts after 2 (M2) and 4 (M4) months of treatment. At M2, CLR-RIF-EMB was slightly but significantly more efficient than CFZ-RIF-EMB (3.02 ± 0.12 versus 3.55 ± 0.28, respectively, P < 0.01), whereas CLR-CFZ-EMB and CLR-CFZ-RIF-EMB dramatically decreased lung CFU counts by 4.32 and 4.47 log10, respectively, compared to untreated group. At M4, CLR-RIF-EMB was significantly more efficient than CFZ-RIF-EMB (2 ± 0.53 versus 2.66 ± 0.22, respectively, P = 0.01). The addition of CLZ to CLR dramatically decreased the lung CFU count, with CFU counts 5.41 and 5.79 log10 lower in the CLR-CFZ-EMB and CLR-CFZ-RIF-EMB groups, respectively, than in the untreated group. The addition of CFZ to CLR seems to improve the efficacy of CLR as early as M2 and was confirmed at M4. CFZ, in addition to RIF and EMB, on the other hand, is less effective than CLR-RIF-EMB. These results need to be confirmed by similar studies along with CFZ potential for shortening treatment.


Assuntos
Antituberculosos/uso terapêutico , Claritromicina/uso terapêutico , Clofazimina/uso terapêutico , Infecção por Mycobacterium avium-intracellulare/tratamento farmacológico , Mycobacterium avium/efeitos dos fármacos , Aerossóis , Animais , Antituberculosos/administração & dosagem , Claritromicina/administração & dosagem , Clofazimina/farmacologia , Contagem de Colônia Microbiana , Sinergismo Farmacológico , Etambutol/uso terapêutico , Feminino , Pulmão/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Infecção por Mycobacterium avium-intracellulare/microbiologia , Rifampina/uso terapêutico , Resultado do Tratamento
19.
PLoS Negl Trop Dis ; 14(1): e0007481, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31961864

RESUMO

BACKGROUND: Crystal violet (CV) was used for several years in blood banks to eliminate the parasite Trypanosoma cruzi in endemic areas in order to prevent transfusion-transmitted Chagas disease. One mechanism of action described for CV involves inhibition of proline uptake. In T. cruzi, proline is essential for host cell infection and intracellular differentiation among other processes, and can be obtained through the proline permease TcAAAP069. METHODOLOGY/PRINCIPAL FINDINGS: CV inhibited proline transporter TcAAAP069 and parasites overexpressing this permease were 47-fold more sensitive to this compound than control parasites. Using CV as reference molecule, loratadine, cyproheptadine, olanzapine and clofazimine were identified as structurally related compounds to CV (structural analogues) by in silico drug repurposing through a similarity-based virtual screening protocol. All these already-approved drugs for clinical use inhibited TcAAAP069 activity with different efficacies and also presented trypanocidal action in epimastigotes, trypomastigotes and amastigotes of the Y, CL Brener and Dm28c T. cruzi strains. Finally, a synergistic effect between benznidazole and the CV chemical analogues was evidenced by combination and dose-reduction indexes values in epimastigotes and trypomastigotes of the Y strain. CONCLUSIONS/SIGNIFICANCE: Loratadine, cyproheptadine and clofazimine inhibit TcAAAP069 proline transporter and also present trypanocidal effect against all T. cruzi life stages in strains from three different DTUs. These CV structural analogues could be a starting point to design therapeutic alternatives to treat Chagas disease by finding new indications for old drugs. This approach, called drug repurposing is a recommended strategy by the World Health Organization to treat neglected diseases, like Chagas disease, and combination therapy may improve the possibility of success of repositioned drugs.


Assuntos
Sistemas de Transporte de Aminoácidos Neutros/antagonistas & inibidores , Violeta Genciana/química , Violeta Genciana/farmacologia , Proteínas de Protozoários/antagonistas & inibidores , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Sistemas de Transporte de Aminoácidos Neutros/genética , Sistemas de Transporte de Aminoácidos Neutros/metabolismo , Doença de Chagas/parasitologia , Clofazimina/farmacologia , Simulação por Computador , Reposicionamento de Medicamentos , Humanos , Estágios do Ciclo de Vida/efeitos dos fármacos , Loratadina/farmacologia , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Tripanossomicidas/química , Trypanosoma cruzi/genética , Trypanosoma cruzi/crescimento & desenvolvimento , Trypanosoma cruzi/metabolismo
20.
Haematologica ; 105(4): 971-986, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31371410

RESUMO

Leukemia stem cells contribute to drug-resistance and relapse in chronic myeloid leukemia (CML) and BCR-ABL1 inhibitor monotherapy fails to eliminate these cells, thereby necessitating alternate therapeutic strategies for patients CML. The peroxisome proliferator-activated receptor-γ (PPARγ) agonist pioglitazone downregulates signal transducer and activator of transcription 5 (STAT5) and in combination with imatinib induces complete molecular response in imatinib-refractory patients by eroding leukemia stem cells. Thiazolidinediones such as pioglitazone are, however, associated with severe side effects. To identify alternate therapeutic strategies for CML we screened Food and Drug Administration-approved drugs in K562 cells and identified the leprosy drug clofazimine as an inhibitor of viability of these cells. Here we show that clofazimine induced apoptosis of blood mononuclear cells derived from patients with CML, with a particularly robust effect in imatinib-resistant cells. Clofazimine also induced apoptosis of CD34+38- progenitors and quiescent CD34+ cells from CML patients but not of hematopoietic progenitor cells from healthy donors. Mechanistic evaluation revealed that clofazimine, via physical interaction with PPARγ, induced nuclear factor kB-p65 proteasomal degradation, which led to sequential myeloblastoma oncoprotein and peroxiredoxin 1 downregulation and concomitant induction of reactive oxygen species-mediated apoptosis. Clofazimine also suppressed STAT5 expression and consequently downregulated stem cell maintenance factors hypoxia-inducible factor-1α and -2α and Cbp/P300 interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2 (CITED2). Combining imatinib with clofazimine caused a far superior synergy than that with pioglitazone, with clofazimine reducing the half maximal inhibitory concentration (IC50) of imatinib by >4 logs and remarkably eroding quiescent CD34+ cells. In a K562 xenograft study clofazimine and imatinib co-treatment showed more robust efficacy than the individual treatments. We propose clinical evaluation of clofazimine in imatinib-refractory CML.


Assuntos
Hanseníase , Leucemia Mielogênica Crônica BCR-ABL Positiva , Preparações Farmacêuticas , Apoptose , Clofazimina/farmacologia , Resistencia a Medicamentos Antineoplásicos , Proteínas de Fusão bcr-abl/genética , Humanos , Mesilato de Imatinib/farmacologia , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , PPAR gama
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...