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1.
Int J Parasitol Drugs Drug Resist ; 25: 100537, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38810336

RESUMO

Target-based approaches have traditionally been used in the search for new anti-infective molecules. Target selection process, a critical step in Drug Discovery, identifies targets that are essential to establish or maintain the infection, tractable to be susceptible for inhibition, selective towards their human ortholog and amenable for large scale purification and high throughput screening. The work presented herein validates the Plasmodium falciparum mRNA 5' triphosphatase (PfPRT1), the first enzymatic step to cap parasite nuclear mRNAs, as a candidate target for the development of new antimalarial compounds. mRNA capping is essential to maintain the integrity and stability of the messengers, allowing their translation. PfPRT1 has been identified as a member of the tunnel, metal dependent mRNA 5' triphosphatase family which differs structurally and mechanistically from human metal independent mRNA 5' triphosphatase. In the present study the essentiality of PfPRT1 was confirmed and molecular biology tools and methods for target purification, enzymatic assessment and target engagement were developed, with the goal of running a future high throughput screening to discover PfPRT1 inhibitors.

2.
Science ; 381(6657): 533-540, 2023 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-37535741

RESUMO

Malaria control demands the development of a wide range of complementary strategies. We describe the properties of a naturally occurring, non-genetically modified symbiotic bacterium, Delftia tsuruhatensis TC1, which was isolated from mosquitoes incapable of sustaining the development of Plasmodium falciparum parasites. D. tsuruhatensis TC1 inhibits early stages of Plasmodium development and subsequent transmission by the Anopheles mosquito through secretion of a small-molecule inhibitor. We have identified this inhibitor to be the hydrophobic molecule harmane. We also found that, on mosquito contact, harmane penetrates the cuticle, inhibiting Plasmodium development. D. tsuruhatensis TC1 stably populates the mosquito gut, does not impose a fitness cost on the mosquito, and inhibits Plasmodium development for the mosquito's life. Contained field studies in Burkina Faso and modeling showed that D. tsuruhatensis TC1 has the potential to complement mosquito-targeted malaria transmission control.


Assuntos
Anopheles , Delftia , Interações Hospedeiro-Parasita , Malária Falciparum , Plasmodium falciparum , Animais , Anopheles/microbiologia , Malária Falciparum/microbiologia , Malária Falciparum/prevenção & controle , Malária Falciparum/transmissão , Plasmodium falciparum/microbiologia , Plasmodium falciparum/fisiologia , Delftia/fisiologia , Simbiose , Humanos
3.
Molecules ; 27(14)2022 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-35889319

RESUMO

Mycobacterium tuberculosis (Mtb), the etiological agent of tuberculosis, is one of the most devastating infectious agents in the world. Chemical-genetic characterization through in vitro evolution combined with whole genome sequencing analysis was used identify novel drug targets and drug resistance genes in Mtb associated with its intracellular growth in human macrophages. We performed a genome analysis of 53 Mtb mutants resistant to 15 different hit compounds. We found nonsynonymous mutations/indels in 30 genes that may be associated with drug resistance acquisitions. Beyond confirming previously identified drug resistance mechanisms such as rpoB and lead targets reported in novel anti-tuberculosis drug screenings such as mmpL3, ethA, and mbtA, we have discovered several unrecognized candidate drug targets including prrB. The exploration of the Mtb chemical mutant genomes could help novel drug discovery and the structural biology of compounds and associated mechanisms of action relevant to tuberculosis treatment.


Assuntos
Antituberculosos , Mycobacterium tuberculosis , Antituberculosos/farmacologia , Proteínas de Bactérias/genética , Humanos , Mutação INDEL , Macrófagos/microbiologia , Testes de Sensibilidade Microbiana , Mutação , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/genética , Tuberculose/microbiologia
4.
Trials ; 23(1): 559, 2022 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-35804454

RESUMO

BACKGROUND: Buruli ulcer (BU) is a neglected tropical disease caused by Mycobacterium ulcerans that affects skin, soft tissues, and bones, causing long-term morbidity, stigma, and disability. The recommended treatment for BU requires 8 weeks of daily rifampicin and clarithromycin together with wound care, physiotherapy, and sometimes tissue grafting and surgery. Recovery can take up to 1 year, and it may pose an unbearable financial burden to the household. Recent in vitro studies demonstrated that beta-lactams combined with rifampicin and clarithromycin are synergistic against M. ulcerans. Consequently, inclusion of amoxicillin/clavulanate in a triple oral therapy may potentially improve and shorten the healing process. The BLMs4BU trial aims to assess whether co-administration of amoxicillin/clavulanate with rifampicin and clarithromycin could reduce BU treatment from 8 to 4 weeks. METHODS: We propose a randomized, controlled, open-label, parallel-group, non-inferiority phase II, multi-centre trial in Benin with participants stratified according to BU category lesions and randomized to two oral regimens: (i) Standard: rifampicin plus clarithromycin therapy for 8 weeks; and (ii) Investigational: standard plus amoxicillin/clavulanate for 4 weeks. The primary efficacy outcome will be lesion healing without recurrence and without excision surgery 12 months after start of treatment (i.e. cure rate). Seventy clinically diagnosed BU patients will be recruited per arm. Patients will be followed up over 12 months and managed according to standard clinical care procedures. Decision for excision surgery will be delayed to 14 weeks after start of treatment. Two sub-studies will also be performed: a pharmacokinetic and a microbiology study. DISCUSSION: If successful, this study will create a new paradigm for BU treatment, which could inform World Health Organization policy and practice. A shortened, highly effective, all-oral regimen will improve care of BU patients and will lead to a decrease in hospitalization-related expenses and indirect and social costs and improve treatment adherence. This trial may also provide information on treatment shortening strategies for other mycobacterial infections (tuberculosis, leprosy, or non-tuberculous mycobacteria infections). TRIAL REGISTRATION: ClinicalTrials.gov NCT05169554 . Registered on 27 December 2021.


Assuntos
Antibacterianos , Úlcera de Buruli , Combinação Amoxicilina e Clavulanato de Potássio/uso terapêutico , Antibacterianos/uso terapêutico , Benin , Úlcera de Buruli/tratamento farmacológico , Claritromicina/uso terapêutico , Ensaios Clínicos Fase II como Assunto , Humanos , Estudos Multicêntricos como Assunto , Ensaios Clínicos Controlados Aleatórios como Assunto , Rifampina/uso terapêutico , Resultado do Tratamento
5.
Sci Transl Med ; 14(643): eaaz6280, 2022 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-35507672

RESUMO

The sensitivity of Mycobacterium tuberculosis, the pathogen that causes tuberculosis (TB), to antibiotic prodrugs is dependent on the efficacy of the activation process that transforms the prodrugs into their active antibacterial moieties. Various oxidases of M. tuberculosis have the potential to activate the prodrug ethionamide. Here, we used medicinal chemistry coupled with a phenotypic assay to select the N-acylated 4-phenylpiperidine compound series. The lead compound, SMARt751, interacted with the transcriptional regulator VirS of M. tuberculosis, which regulates the mymA operon encoding a monooxygenase that activates ethionamide. SMARt751 boosted the efficacy of ethionamide in vitro and in mouse models of acute and chronic TB. SMARt751 also restored full efficacy of ethionamide in mice infected with M. tuberculosis strains carrying mutations in the ethA gene, which cause ethionamide resistance in the clinic. SMARt751 was shown to be safe in tests conducted in vitro and in vivo. A model extrapolating animal pharmacokinetic and pharmacodynamic parameters to humans predicted that as little as 25 mg of SMARt751 daily would allow a fourfold reduction in the dose of ethionamide administered while retaining the same efficacy and reducing side effects.


Assuntos
Mycobacterium tuberculosis , Pró-Fármacos , Tuberculose , Animais , Antituberculosos/farmacologia , Antituberculosos/uso terapêutico , Etionamida/química , Etionamida/farmacologia , Etionamida/uso terapêutico , Camundongos , Pró-Fármacos/farmacologia , Pró-Fármacos/uso terapêutico , Tuberculose/tratamento farmacológico
6.
ACS Infect Dis ; 7(1): 141-152, 2021 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-33319550

RESUMO

MmpL3, an essential mycolate transporter in the inner membrane of Mycobacterium tuberculosis (Mtb), has been identified as a target of multiple, chemically diverse antitubercular drugs. However, several of these molecules seem to have secondary targets and inhibit bacterial growth by more than one mechanism. Here, we describe a cell-based assay that utilizes two-way regulation of MmpL3 expression to readily identify MmpL3-specific inhibitors. We successfully used this assay to identify a novel guanidine-based MmpL3 inhibitor from a library of 220 compounds that inhibit growth of Mtb by largely unknown mechanisms. We furthermore identified inhibitors of cytochrome bc1-aa3 oxidase as one class of off-target hits in whole-cell screens for MmpL3 inhibitors and report a novel sulfanylacetamide as a potential QcrB inhibitor.


Assuntos
Proteínas de Bactérias , Proteínas de Membrana Transportadoras , Mycobacterium tuberculosis , Antituberculosos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Mycobacterium tuberculosis/metabolismo , Ácidos Micólicos
7.
Artigo em Inglês | MEDLINE | ID: mdl-31182528

RESUMO

This first-time-in-human (FTIH) study evaluated the safety, tolerability, pharmacokinetics, and food effect of single and repeat oral doses of GSK3036656, a leucyl-tRNA synthetase inhibitor. In part A, GSK3036656 single doses of 5 mg (fed and fasted), 15 mg, and 25 mg and placebo were administered. In part B, repeat doses of 5 and 15 mg and placebo were administered for 14 days once daily. GSK3036656 showed dose-proportional increase following single-dose administration and after dosing for 14 days. The maximum concentration of drug in serum (Cmax) and area under the concentration-time curve from 0 h to the end of the dosing period (AUC0-τ) showed accumulation with repeated administration of approximately 2- to 3-fold. Pharmacokinetic parameters were not altered in the presence of food. Unchanged GSK3036656 was the only drug-related component detected in plasma and accounted for approximately 90% of drug-related material in urine. Based on total drug-related material detected in urine, the minimum absorbed doses after single (25 mg) and repeat (15 mg) dosing were 50 and 78%, respectively. Unchanged GSK3036656 represented at least 44% and 71% of the 25- and 15-mg doses, respectively. Clinical trial simulations were performed to guide dose escalation during the FTIH study and to predict the GSK3036656 dose range that produces the highest possible early bactericidal activity (EBA0-14) in the prospective phase II trial, with consideration of the predefined exposure limit. GSK3036656 was well tolerated after single and multiple doses, with no reports of serious adverse events. (This study has been registered at ClinicalTrials.gov under identifier NCT03075410.).


Assuntos
Antituberculosos/farmacologia , Compostos de Boro/farmacologia , Compostos Heterocíclicos com 2 Anéis/farmacologia , Tuberculose/tratamento farmacológico , Administração Oral , Adolescente , Adulto , Antituberculosos/administração & dosagem , Antituberculosos/efeitos adversos , Antituberculosos/farmacocinética , Área Sob a Curva , Compostos de Boro/administração & dosagem , Compostos de Boro/efeitos adversos , Compostos de Boro/farmacocinética , Método Duplo-Cego , Inibidores Enzimáticos/farmacologia , Feminino , Alimentos , Compostos Heterocíclicos com 2 Anéis/administração & dosagem , Compostos Heterocíclicos com 2 Anéis/efeitos adversos , Compostos Heterocíclicos com 2 Anéis/farmacocinética , Humanos , Leucina-tRNA Ligase/antagonistas & inibidores , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Placebos , Adulto Jovem
8.
ACS Infect Dis ; 5(8): 1433-1445, 2019 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-31184461

RESUMO

The historical view of ß-lactams as ineffective antimycobacterials has given way to growing interest in the activity of this class against Mycobacterium tuberculosis (Mtb) in the presence of a ß-lactamase inhibitor. However, most antimycobacterial ß-lactams kill Mtb only or best when the bacilli are replicating. Here, a screen of 1904 ß-lactams led to the identification of cephalosporins substituted with a pyrithione moiety at C3' that are active against Mtb under both replicating and nonreplicating conditions, neither activity requiring a ß-lactamase inhibitor. Studies showed that activity against nonreplicating Mtb required the in situ release of the pyrithione, independent of the known class A ß-lactamase, BlaC. In contrast, replicating Mtb could be killed both by released pyrithione and by the parent ß-lactam. Thus, the antimycobacterial activity of pyrithione-containing cephalosporins arises from two mechanisms that kill mycobacteria in different metabolic states.


Assuntos
Antituberculosos/farmacologia , Cefalosporinas/farmacologia , Replicação do DNA , Mycobacterium tuberculosis/efeitos dos fármacos , Piridinas/farmacologia , Tionas/farmacologia , Administração Oral , Animais , Antituberculosos/administração & dosagem , Callithrix , Cefalosporinas/administração & dosagem , Descoberta de Drogas , Feminino , Células Hep G2 , Ensaios de Triagem em Larga Escala , Humanos , Camundongos , Mycobacterium tuberculosis/fisiologia , Piridinas/administração & dosagem , Tionas/administração & dosagem
9.
Sci Adv ; 5(3): eaav2104, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30906866

RESUMO

The stringent response enables Mycobacterium tuberculosis (Mtb) to shut down its replication and metabolism under various stresses. Here we show that Mtb lacking the stringent response enzyme RelMtb was unable to slow its replication rate during nutrient starvation. Metabolomics analysis revealed that the nutrient-starved relMtb -deficient strain had increased metabolism similar to that of exponentially growing wild-type bacteria in nutrient-rich broth, consistent with an inability to enter quiescence. Deficiency of relMtb increased the susceptibility of mutant bacteria to killing by isoniazid during nutrient starvation and in the lungs of chronically infected mice. We screened a pharmaceutical library of over 2 million compounds for inhibitors of RelMtb and showed that the lead compound X9 was able to directly kill nutrient-starved M. tuberculosis and enhanced the killing activity of isoniazid. Inhibition of RelMtb is a promising approach to target M. tuberculosis persisters, with the potential to shorten the duration of TB treatment.


Assuntos
Proteínas de Bactérias/genética , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Mycobacterium tuberculosis/efeitos dos fármacos , Tuberculose/genética , Animais , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Cristalografia por Raios X , Replicação do DNA/efeitos dos fármacos , Proteínas de Escherichia coli/antagonistas & inibidores , Proteínas de Escherichia coli/química , GTP Pirofosfoquinase/antagonistas & inibidores , GTP Pirofosfoquinase/química , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/química , Peptídeos e Proteínas de Sinalização Intracelular/genética , Isoniazida/química , Isoniazida/farmacologia , Camundongos , Mycobacterium tuberculosis/química , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/patogenicidade , Conformação Proteica , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Tuberculose/tratamento farmacológico , Tuberculose/microbiologia , Tuberculose/patologia
10.
PLoS Negl Trop Dis ; 13(1): e0007126, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30689630

RESUMO

The potential use of clinically approved beta-lactams for Buruli ulcer (BU) treatment was investigated with representative classes analyzed in vitro for activity against Mycobacterium ulcerans. Beta-lactams tested were effective alone and displayed a strong synergistic profile in combination with antibiotics currently used to treat BU, i.e. rifampicin and clarithromycin; this activity was further potentiated in the presence of the beta-lactamase inhibitor clavulanate. In addition, quadruple combinations of rifampicin, clarithromycin, clavulanate and beta-lactams resulted in multiplicative reductions in their minimal inhibitory concentration (MIC) values. The MIC of amoxicillin against a panel of clinical isolates decreased more than 200-fold within this quadruple combination. Amoxicillin/clavulanate formulations are readily available with clinical pedigree, low toxicity, and orally and pediatric available; thus, supporting its potential inclusion as a new anti-BU drug in current combination therapies.


Assuntos
Úlcera de Buruli/tratamento farmacológico , Mycobacterium ulcerans/efeitos dos fármacos , Inibidores de beta-Lactamases/farmacologia , beta-Lactamases/metabolismo , Administração Oral , Amoxicilina/farmacologia , Amoxicilina/uso terapêutico , Úlcera de Buruli/microbiologia , Claritromicina/farmacologia , Claritromicina/uso terapêutico , Ácido Clavulânico/farmacologia , Ácido Clavulânico/uso terapêutico , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Quimioterapia Combinada , Humanos , Testes de Sensibilidade Microbiana , Mycobacterium ulcerans/enzimologia , Rifampina/farmacologia , Rifampina/uso terapêutico , Inibidores de beta-Lactamases/uso terapêutico
11.
Sci Rep ; 8(1): 13473, 2018 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-30194385

RESUMO

Nitro-substituted 1,3-benzothiazinones (nitro-BTZs) are mechanism-based covalent inhibitors of Mycobacterium tuberculosis decaprenylphosphoryl-ß-D-ribose-2'-oxidase (DprE1) with strong antimycobacterial properties. We prepared a number of oxidized and reduced forms of nitro-BTZs to probe the mechanism of inactivation of the enzyme and to identify opportunities for further chemistry. The kinetics of inactivation of DprE1 was examined using an enzymatic assay that monitored reaction progress up to 100 min, permitting compound ranking according to kinact/Ki values. The side-chain at the 2-position and heteroatom identity at the 1-position of the BTZs were found to be important for inhibitory activity. We obtained crystal structures with several compounds covalently bound. The data suggest that steps upstream from the covalent end-points are likely the key determinants of potency and reactivity. The results of protein mass spectrometry using a 7-chloro-nitro-BTZ suggest that nucleophilic reactions at the 7-position do not operate and support a previously proposed mechanism in which BTZ activation by a reduced flavin intermediate is required. Unexpectedly, a hydroxylamino-BTZ showed time-dependent inhibition and mass spectrometry corroborated that this hydroxylamino-BTZ is a mechanism-based suicide inhibitor of DprE1. With this BTZ derivative, we propose a new covalent mechanism of inhibition of DprE1 that takes advantage of the oxidation cycle of the enzyme.


Assuntos
Oxirredutases do Álcool , Antituberculosos/química , Proteínas de Bactérias , Inibidores Enzimáticos/química , Mycobacterium tuberculosis/enzimologia , Oxirredutases do Álcool/antagonistas & inibidores , Oxirredutases do Álcool/química , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Cristalografia por Raios X , Espectrometria de Massas
12.
Sci Rep ; 8(1): 12664, 2018 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-30140040

RESUMO

Mycobacterium tuberculosis, the causative agent of tuberculosis, has surpassed HIV as the leading cause of death due to an infectious disease worldwide, being responsible for more than 1.5 million deaths in low-income countries. In response to a pandemic threat by drug resistant strains, the tuberculosis research community is searching for new chemical entities with novel mechanisms of action to avoid drug resistance and shorten treatment regimens using combinatorial chemotherapy. Herein, we have identified several novel chemical scaffolds, GSK97C (spiro-oxazolidin-2-one), GSK93A (2-amino-1,3-thiazole, GSK85A and GSK92A (enamides), which target M. tuberculosis aspartyl-tRNA synthetase (Mt-AspRS), an essential component of the protein synthesis machinery of tuberculosis, using a whole-cell target-based screening strategy against a genetically modified Mycobacterium bovis BCG strain. We also provide further evidence of protein inhibition and inhibitor profiling through a classical aminoacylation reaction and a tRNA-independent assay, respectively. Altogether, our results have identified a number of hit new molecules with novel mechanism of action for further development through medicinal chemistry as hits and leads.


Assuntos
Antituberculosos/farmacologia , Aspartato-tRNA Ligase/metabolismo , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/enzimologia , Aspartato-tRNA Ligase/antagonistas & inibidores , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/farmacologia , Testes de Sensibilidade Microbiana , Mycobacterium bovis/efeitos dos fármacos , Mycobacterium bovis/enzimologia
14.
Int J Parasitol Drugs Drug Resist ; 8(2): 295-303, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29775797

RESUMO

Phenotypic screening has produced most of the new chemical entities currently in clinical development for malaria, plus many lead compounds active against Plasmodium falciparum asexual stages. However, lack of knowledge about the mode of action of these compounds delays and may even hamper their future development. Identifying the mode of action of the inhibitors greatly helps to prioritise compounds for further development as novel antimalarials. Here we describe a whole-cell method to detect inhibitors of the mitochondrial electron transport chain, using oxygen consumption as high throughput readout in 384-well plate format. The usefulness of the method has been confirmed with the Tres Cantos Antimalarial Compound Set (TCAMS). The assay identified 124 respiratory inhibitors in TCAMS, seven of which were novel anti-plasmodial chemical structures never before described as mitochondrial inhibitors.


Assuntos
Antimaláricos/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Mitocôndrias/efeitos dos fármacos , Plasmodium falciparum/efeitos dos fármacos , Descoberta de Drogas/métodos , Avaliação Pré-Clínica de Medicamentos/instrumentação , Complexo de Proteínas da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Humanos , Concentração Inibidora 50 , Malária/tratamento farmacológico , Malária/parasitologia , Malária Falciparum , Oxigênio/metabolismo , Plasmodium falciparum/citologia
15.
ChemMedChem ; 13(7): 672-677, 2018 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-29399991

RESUMO

Our findings reported herein provide support for the benefits of including functional group complexity (FGC) within fragments when screening against protein targets such as Mycobacterium tuberculosis InhA. We show that InhA fragment actives with FGC maintained their binding pose during elaboration. Furthermore, weak fragment hits with functional group handles also allowed for facile fragment elaboration to afford novel and potent InhA inhibitors with good ligand efficiency metrics for optimization.


Assuntos
Antituberculosos/química , Proteínas de Bactérias/antagonistas & inibidores , Inibidores Enzimáticos/química , Mycobacterium tuberculosis/enzimologia , Oxirredutases/antagonistas & inibidores , Bibliotecas de Moléculas Pequenas/química , Antituberculosos/síntese química , Proteínas de Bactérias/química , Cristalografia por Raios X , Inibidores Enzimáticos/síntese química , Ligantes , Modelos Moleculares , Estrutura Molecular , Oxirredutases/química , Bibliotecas de Moléculas Pequenas/síntese química , Ressonância de Plasmônio de Superfície
16.
J Med Chem ; 60(19): 8011-8026, 2017 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-28953378

RESUMO

There is an urgent need to develop new and safer antitubercular agents that possess a novel mode of action. We synthesized and evaluated a novel series of 3-aminomethyl 4-halogen benzoxaboroles as Mycobacterium tuberculosis (Mtb) leucyl-tRNA synthetase (LeuRS) inhibitors. A number of Mtb LeuRS inhibitors were identified that demonstrated good antitubercular activity with high selectivity over human mitochondrial and cytoplasmic LeuRS. Further evaluation of these Mtb LeuRS inhibitors by in vivo pharmacokinetics (PK) and murine tuberculosis (TB) efficacy models led to the discovery of GSK3036656 (abbreviated as GSK656). This molecule shows potent inhibition of Mtb LeuRS (IC50 = 0.20 µM) and in vitro antitubercular activity (Mtb H37Rv MIC = 0.08 µM). Additionally, it is highly selective for the Mtb LeuRS enzyme with IC50 of >300 µM and 132 µM for human mitochondrial LeuRS and human cytoplasmic LeuRS, respectively. In addition, it exhibits remarkable PK profiles and efficacy against Mtb in mouse TB infection models with superior tolerability over initial leads. This compound has been progressed to clinical development for the treatment of tuberculosis.


Assuntos
Antituberculosos/síntese química , Antituberculosos/farmacologia , Compostos de Boro/farmacologia , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Compostos Heterocíclicos com 2 Anéis/farmacologia , Leucina-tRNA Ligase/antagonistas & inibidores , Mycobacterium tuberculosis/efeitos dos fármacos , Animais , Antituberculosos/farmacocinética , Compostos de Boro/síntese química , Compostos de Boro/farmacocinética , Descoberta de Drogas , Inibidores Enzimáticos/farmacocinética , Feminino , Compostos Heterocíclicos com 2 Anéis/síntese química , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Mycobacterium tuberculosis/enzimologia , Relação Estrutura-Atividade , Especificidade por Substrato
17.
Nat Commun ; 8: 16081, 2017 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-28714473

RESUMO

The identification and prioritization of chemically tractable therapeutic targets is a significant challenge in the discovery of new medicines. We have developed a novel method that rapidly screens multiple proteins in parallel using DNA-encoded library technology (ELT). Initial efforts were focused on the efficient discovery of antibacterial leads against 119 targets from Acinetobacter baumannii and Staphylococcus aureus. The success of this effort led to the hypothesis that the relative number of ELT binders alone could be used to assess the ligandability of large sets of proteins. This concept was further explored by screening 42 targets from Mycobacterium tuberculosis. Active chemical series for six targets from our initial effort as well as three chemotypes for DHFR from M. tuberculosis are reported. The findings demonstrate that parallel ELT selections can be used to assess ligandability and highlight opportunities for successful lead and tool discovery.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/farmacologia , Descoberta de Drogas/métodos , Biblioteca Gênica , Mycobacterium tuberculosis/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas , Staphylococcus aureus/efeitos dos fármacos , Acinetobacter baumannii/metabolismo , Avaliação Pré-Clínica de Medicamentos , Terapia de Alvo Molecular , Mycobacterium tuberculosis/metabolismo , Staphylococcus aureus/metabolismo
18.
Sci Rep ; 6: 34293, 2016 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-27678056

RESUMO

While modern cephalosporins developed for broad spectrum antibacterial activities have never been pursued for tuberculosis (TB) therapy, we identified first generation cephalosporins having clinically relevant inhibitory concentrations, both alone and in synergistic drug combinations. Common chemical patterns required for activity against Mycobacterium tuberculosis were identified using structure-activity relationships (SAR) studies. Numerous cephalosporins were synergistic with rifampicin, the cornerstone drug for TB therapy, and ethambutol, a first-line anti-TB drug. Synergy was observed even under intracellular growth conditions where beta-lactams typically have limited activities. Cephalosporins and rifampicin were 4- to 64-fold more active in combination than either drug alone; however, limited synergy was observed with rifapentine or rifabutin. Clavulanate was a key synergistic partner in triple combinations. Cephalosporins (and other beta-lactams) together with clavulanate rescued the activity of rifampicin against a rifampicin resistant strain. Synergy was not due exclusively to increased rifampicin accumulation within the mycobacterial cells. Cephalosporins were also synergistic with new anti-TB drugs such as bedaquiline and delamanid. Studies will be needed to validate their in vivo activities. However, the fact that cephalosporins are orally bioavailable with good safety profiles, together with their anti-mycobacterial activities reported here, suggest that they could be repurposed within new combinatorial TB therapies.

19.
EBioMedicine ; 8: 291-301, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27428438

RESUMO

Despite being one of the first antitubercular agents identified, isoniazid (INH) is still the most prescribed drug for prophylaxis and tuberculosis (TB) treatment and, together with rifampicin, the pillars of current chemotherapy. A high percentage of isoniazid resistance is linked to mutations in the pro-drug activating enzyme KatG, so the discovery of direct inhibitors (DI) of the enoyl-ACP reductase (InhA) has been pursued by many groups leading to the identification of different enzyme inhibitors, active against Mycobacterium tuberculosis (Mtb), but with poor physicochemical properties to be considered as preclinical candidates. Here, we present a series of InhA DI active against multidrug (MDR) and extensively (XDR) drug-resistant clinical isolates as well as in TB murine models when orally dosed that can be a promising foundation for a future treatment.


Assuntos
Antituberculosos/farmacologia , Enoil-(Proteína de Transporte de Acila) Redutase (NADH)/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/enzimologia , Animais , Antituberculosos/química , Sítios de Ligação , Domínio Catalítico , Modelos Animais de Doenças , Enoil-(Proteína de Transporte de Acila) Redutase (NADH)/genética , Enoil-(Proteína de Transporte de Acila) Redutase (NADH)/metabolismo , Inibidores Enzimáticos/química , Feminino , Humanos , Camundongos , Testes de Sensibilidade Microbiana , Microssomos , Modelos Moleculares , Mutação , Mycobacterium tuberculosis/genética , Ligação Proteica , Conformação Proteica , Tuberculose/tratamento farmacológico , Tuberculose/microbiologia , Tuberculose/mortalidade , Tuberculose Resistente a Múltiplos Medicamentos
20.
Proc Natl Acad Sci U S A ; 113(31): E4523-30, 2016 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-27432954

RESUMO

The rising incidence of antimicrobial resistance (AMR) makes it imperative to understand the underlying mechanisms. Mycobacterium tuberculosis (Mtb) is the single leading cause of death from a bacterial pathogen and estimated to be the leading cause of death from AMR. A pyrido-benzimidazole, 14, was reported to have potent bactericidal activity against Mtb. Here, we isolated multiple Mtb clones resistant to 14. Each had mutations in the putative DNA-binding and dimerization domains of rv2887, a gene encoding a transcriptional repressor of the MarR family. The mutations in Rv2887 led to markedly increased expression of rv0560c. We characterized Rv0560c as an S-adenosyl-L-methionine-dependent methyltransferase that N-methylates 14, abolishing its mycobactericidal activity. An Mtb strain lacking rv0560c became resistant to 14 by mutating decaprenylphosphoryl-ß-d-ribose 2-oxidase (DprE1), an essential enzyme in arabinogalactan synthesis; 14 proved to be a nanomolar inhibitor of DprE1, and methylation of 14 by Rv0560c abrogated this activity. Thus, 14 joins a growing list of DprE1 inhibitors that are potently mycobactericidal. Bacterial methylation of an antibacterial agent, 14, catalyzed by Rv0560c of Mtb, is a previously unreported mechanism of AMR.


Assuntos
Antituberculosos/metabolismo , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana , Mycobacterium tuberculosis/metabolismo , Antituberculosos/química , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Benzimidazóis/química , Benzimidazóis/metabolismo , Regulação Bacteriana da Expressão Gênica , Metilação , Metiltransferases/química , Metiltransferases/genética , Metiltransferases/metabolismo , Modelos Moleculares , Estrutura Molecular , Mutação , Mycobacterium tuberculosis/genética , Domínios Proteicos , Proteínas Repressoras/química , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , S-Adenosilmetionina/metabolismo
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