Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 40
Filtrar
2.
Front Psychiatry ; 14: 1196907, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37426099

RESUMEN

Introduction: Online psychotherapy is a form of work that is becoming more and more popular. Public health problems, such as COVID-19, forced mental health professionals and patients to incorporate new methodologies such as the use of electronic media and internet to provide follow-up, treatment and also supervision. The aim of this study was to investigate which factors shape the therapists' attitudes toward online psychotherapy during a pandemic taking into account: (1) attitudes toward the COVID-19 pandemic (fear of contagion, pandemic fatigue, etc.), (2) personal characteristics of the psychotherapists (age, gender, feeling of efficacy, anxiety, depression, etc.), and (3) characteristics of the psychotherapeutic practice (guideline procedure, client age group, professional experience, etc). Materials and methods: Study participants were 177 psychotherapists from four European countries: Poland (n = 48), Germany (n = 44), Sweden (n = 49), and Portugal (n = 36). Data were collected by means of an individual online survey through the original questionnaire and the standardized scales: a modified version of the Attitudes toward Psychological Online Interventions Scale (APOI), Fear of Contagion by COVID-19 Scale (FCS COVID-19), Pandemic Fatigue Scale (PFS), Hospital Anxiety and Depression Scale (HADS), Social Support Questionnaire (F-SozU K-14), and the Sense of Efficiency Test (SET). Results: Determinants that impacted psychotherapists' attitudes toward online therapy were: COVID-19 belief in prevention-keeping distance and hand disinfection, pandemic behavioral fatigue, previous online therapy experience (including voice call), working with youth and adults. Our study showed that belief in the sense of prevention in the form of taking care of hand disinfection before the session, pandemic behavioral fatigue and experience in working with adults were significant predictors of negative attitudes of therapists toward online psychological interventions. On the other hand, belief in the sense of prevention in the form of keeping distance during the session had a positive effect on general attitudes toward therapy conducted via the internet. Discussion: The online therapy boom during the COVID-19 pandemic has spawned a powerful tool for psychotherapists. More research in this area and training of psychotherapists are needed for online psychological interventions to become an effective therapy format that is accepted by patients and therapists alike.

3.
Antimicrob Agents Chemother ; 67(1): e0129422, 2023 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-36602336

RESUMEN

Despite the deployment of combination tuberculosis (TB) chemotherapy, efforts to identify shorter, nonrelapsing treatments have resulted in limited success. Recent evidence indicates that GSK2556286 (GSK286), which acts via Rv1625c, a membrane-bound adenylyl cyclase in Mycobacterium tuberculosis, shortens treatment in rodents relative to standard of care drugs. Moreover, GSK286 can replace linezolid in the three-drug, Nix-TB regimen. Given its therapeutic potential, we sought to better understand the mechanism of action of GSK286. The compound blocked growth of M. tuberculosis in cholesterol media and increased intracellular cAMP levels ~50-fold. GSK286 did not inhibit growth of an rv1625c transposon mutant in cholesterol media and did not induce cyclic AMP (cAMP) production in this mutant, suggesting that the compound acts on this adenylyl cyclase. GSK286 also induced cAMP production in Rhodococcus jostii RHA1, a cholesterol-catabolizing actinobacterium, when Rv1625c was heterologously expressed. However, these elevated levels of cAMP did not inhibit growth of R. jostii RHA1 in cholesterol medium. Mutations in rv1625c conferred cross-resistance to GSK286 and the known Rv1625c agonist, mCLB073. Metabolic profiling of M. tuberculosis cells revealed that elevated cAMP levels, induced using either an agonist or a genetic tool, did not significantly affect pools of steroid metabolites in cholesterol-incubated cells. Finally, the inhibitory effect of agonists was not dependent on the N-acetyltransferase MtPat. Together, these data establish that GSK286 is an Rv1625c agonist and sheds light on how cAMP signaling can be manipulated as a novel antibiotic strategy to shorten TB treatments. Nevertheless, the detailed mechanism of action of these compounds remains to be elucidated.


Asunto(s)
Mycobacterium tuberculosis , Tuberculosis , Humanos , AMP Cíclico/metabolismo , Adenilil Ciclasas/genética , Adenilil Ciclasas/metabolismo , Colesterol/metabolismo
4.
Antimicrob Agents Chemother ; 66(6): e0013222, 2022 06 21.
Artículo en Inglés | MEDLINE | ID: mdl-35607978

RESUMEN

As a result of a high-throughput compound screening campaign using Mycobacterium tuberculosis-infected macrophages, a new drug candidate for the treatment of tuberculosis has been identified. GSK2556286 inhibits growth within human macrophages (50% inhibitory concentration [IC50] = 0.07 µM), is active against extracellular bacteria in cholesterol-containing culture medium, and exhibits no cross-resistance with known antitubercular drugs. In addition, it has shown efficacy in different mouse models of tuberculosis (TB) and has an adequate safety profile in two preclinical species. These features indicate a compound with a novel mode of action, although still not fully defined, that is effective against both multidrug-resistant (MDR) or extensively drug-resistant (XDR) and drug-sensitive (DS) M. tuberculosis with the potential to shorten the duration of treatment in novel combination drug regimens. (This study has been registered at ClinicalTrials.gov under identifier NCT04472897).


Asunto(s)
Mycobacterium tuberculosis , Tuberculosis Resistente a Múltiples Medicamentos , Tuberculosis , Animales , Antituberculosos/farmacología , Antituberculosos/uso terapéutico , Macrófagos , Ratones , Pruebas de Sensibilidad Microbiana , Tuberculosis/tratamiento farmacológico , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico
6.
Zootaxa ; 4729(4): zootaxa.4729.4.9, 2020 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-32229844

RESUMEN

The rare and diurnal geometrid moth Athroolopha latimargo Rothschild, 1914 bona sp., stat. rev. is re-discovered and redescribed from the furthest point of the south of the Iberian Peninsula, for the first time since its original description as a subspecies of Athroolopha chrysitaria (Hübner, 1813) from North Africa. The range of this taxon is questioned. A mitochondrial COI barcode sequence was generated for the specimens and compared with Iberian and Sicilian Athroolopha species.


Asunto(s)
Lepidópteros , Mariposas Nocturnas , Animales , ADN , Código de Barras del ADN Taxonómico , Análisis de Secuencia de ADN
7.
Sleep ; 42(3)2019 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-30476296

RESUMEN

Lipid metabolism deregulation constitutes the pathogenic basis for the development of atherosclerosis and justifies a high incidence of cardiovascular-related morbidity and mortality. Some data suggest that dyslipidemia may be associated with sleep-disordered breathing, mainly obstructive sleep apnea (OSA), due to alterations in fundamental biochemical processes, such as intermittent hypoxia (IH). The aim of this systematic review was to identify and critically evaluate the current evidence supporting the existence of a possible relationship between OSA and alterations in lipid metabolism. Much evidence shows that, during the fasting state, OSA and IH increase lipid delivery from the adipose tissue to the liver through an up-regulation of the sterol regulatory element-binding protein-1 and stearoyl-CoA desaturase-1, increasing the synthesis of cholesterol esters and triglycerides. In the postprandial state, lipoprotein clearance is delayed due to lower lipoprotein lipase activity, probably secondary to IH-up-regulation of angiopoietin-like protein 4 and decreased activity of the peroxisome proliferator-activated receptor alpha. Moreover, oxidative stress can generate dysfunctional oxidized lipids and reduce the capacity of high-density lipoproteins (HDL) to prevent low-density lipoprotein (LDL) oxidation. In the clinical field, several observational studies and a meta-regression analysis support the existence of a link between OSA and dyslipidemia. Although there is evidence of improved lipid profile after apnea-hypopnea suppression with continuous positive airway pressure (CPAP), the majority of the data come from observational studies. In contrast, randomized controlled trials evaluating the effects of CPAP on lipid metabolism present inconclusive results and two meta-analyses provide contradictory evidence.


Asunto(s)
Aterosclerosis/patología , Dislipidemias/fisiopatología , Metabolismo de los Lípidos/fisiología , Apnea Obstructiva del Sueño/fisiopatología , Animales , Presión de las Vías Aéreas Positiva Contínua/efectos adversos , Modelos Animales de Enfermedad , Ayuno , Humanos , Hipoxia/metabolismo , Lipoproteínas HDL/metabolismo , Lipoproteínas LDL/metabolismo , Hígado/metabolismo , Masculino , Ratones Endogámicos C57BL , Estrés Oxidativo , Estearoil-CoA Desaturasa/metabolismo , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismo , Triglicéridos/sangre , Triglicéridos/metabolismo
8.
J Med Chem ; 61(24): 11221-11249, 2018 12 27.
Artículo en Inglés | MEDLINE | ID: mdl-30500189

RESUMEN

Tuberculosis is the leading cause of death worldwide from infectious diseases. With the development of drug-resistant strains of Mycobacterium tuberculosis, there is an acute need for new medicines with novel modes of action. Herein, we report the discovery and profiling of a novel hydantoin-based family of antimycobacterial inhibitors of the decaprenylphospho-ß-d-ribofuranose 2-oxidase (DprE1). In this study, we have prepared a library of more than a 100 compounds and evaluated them for their biological and physicochemical properties. The series is characterized by high enzymatic and whole-cell activity, low cytotoxicity, and a good overall physicochemical profile. In addition, we show that the series acts via reversible inhibition of the DprE1 enzyme. Overall, the novel compound family forms an attractive base for progression to further stages of optimization and may provide a promising drug candidate in the future.


Asunto(s)
Oxidorreductasas de Alcohol/antagonistas & inhibidores , Antituberculosos/química , Antituberculosos/farmacología , Proteínas Bacterianas/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Hidantoínas/química , Actinobacteria/efectos de los fármacos , Oxidorreductasas de Alcohol/metabolismo , Proteínas Bacterianas/metabolismo , Estabilidad de Medicamentos , Inhibidores Enzimáticos/química , Células Hep G2 , Ensayos Analíticos de Alto Rendimiento/métodos , Humanos , Macrófagos/microbiología , Pruebas de Sensibilidad Microbiana , Mycobacterium tuberculosis/efectos de los fármacos , Reproducibilidad de los Resultados , Relación Estructura-Actividad , Tuberculosis/tratamiento farmacológico , Tuberculosis/microbiología
9.
Cad Saude Publica ; 34(6): e00033317, 2018 06 25.
Artículo en Inglés | MEDLINE | ID: mdl-29952395

RESUMEN

The objective of this study was to investigate the prevalence and factors associated with syphilis in homeless men in Central Brazil. It is a cross-sectional study conducted with 481 individuals attending four therapeutic communities between October and December 2015. A structured interview was conducted to collect sociodemographic data and risk factors for syphilis. Rapid/point-of-care and VDRL tests were performed to determine exposure to syphilis and the presence of active syphilis, respectively. Poisson regression analysis was used to verify the risk factors associated with the outcomes investigated. Of the study participants, 10.2% were reactive to the rapid test, and 5.4% had active syphilis. At the multiple regression analysis, schooling (adjusted prevalence ratio - APR: 0.89; p = 0.005), history of genital ulcer (APR: 2.59; p = 0.002), STI history (APR: 1.97; p = 0.042), and sexual intercourse under drug effects (APR: 1.60; p = 0.022) were independent factors associated with lifetime syphilis. Also, history of genital ulcer (APR: 2.19; p = 0.019), STI history (APR: 1.74; p = 0.033) and number of sexual partners in the last year (APR: 1.02; p = 0.044) were associated with active syphilis. The prevalence of syphilis among homeless men was rather high, confirming the vulnerability of this group to this infection. These results emphasize the need for educational intervention, improvement of risk reduction programs, availability of diagnostic tests, especially the rapid test, and treatment.


Asunto(s)
Personas con Mala Vivienda/estadística & datos numéricos , Sífilis/epidemiología , Sífilis/transmisión , Adulto , Factores de Edad , Brasil/epidemiología , Estudios Transversales , Conductas de Riesgo para la Salud , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Análisis de Regresión , Medición de Riesgo , Factores de Riesgo , Conducta Sexual/estadística & datos numéricos , Factores Socioeconómicos , Trastornos Relacionados con Sustancias/complicaciones , Trastornos Relacionados con Sustancias/epidemiología
10.
Int J STD AIDS ; 29(11): 1084-1088, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-29862902

RESUMEN

Homeless men present high vulnerability to HIV infection, mainly due to sexual risk behaviors and substance use. The objective was to estimate the prevalence of HIV infection, risk behaviors and substance use in homeless men. A cross-sectional study was conducted in 481 homeless men recruited in four therapeutic communities in the Goiás State, Central Brazil. All were interviewed about sociodemographic characteristics, substance use, and risk behaviors. Furthermore, all were tested for HIV. Poisson regression was used to verify factors associated with HIV infection. HIV prevalence was 1.24% (95.0% CI: 0.57 to 2.69%). Previous HIV testing (adjusted prevalence ratio [APR]: 10.0; 95.0% CI: 1.86-55.8) and years of education (APR: 0.76; 95.0% CI: 0.60-0.97) were factors associated with HIV infection. Participants had high rates of hazardous alcohol use and illicit drug use. The prevalence of HIV infection among homeless men was higher than that found in the Brazilian male population and we identified a high rate of risk behaviors for HIV among the homeless men investigated. Thus, it is necessary to expand HIV prevention measures in Brazil, such as health education, condom availability, regular HIV testing and increased testing coverage in this population, and treatment for alcohol and/or illicit drug dependence/abuse.


Asunto(s)
Consumidores de Drogas/psicología , Infecciones por VIH/epidemiología , Infecciones por VIH/prevención & control , Personas con Mala Vivienda/estadística & datos numéricos , Asunción de Riesgos , Conducta Sexual/estadística & datos numéricos , Comunidad Terapéutica , Adulto , Brasil/epidemiología , Estudios Transversales , Consumidores de Drogas/estadística & datos numéricos , Femenino , Infecciones por VIH/diagnóstico , Humanos , Entrevistas como Asunto , Masculino , Persona de Mediana Edad , Prevalencia , Trastornos Relacionados con Sustancias/epidemiología
11.
ChemMedChem ; 13(7): 672-677, 2018 04 06.
Artículo en Inglés | MEDLINE | ID: mdl-29399991

RESUMEN

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.


Asunto(s)
Antituberculosos/química , Proteínas Bacterianas/antagonistas & inhibidores , Inhibidores Enzimáticos/química , Mycobacterium tuberculosis/enzimología , Oxidorreductasas/antagonistas & inhibidores , Bibliotecas de Moléculas Pequeñas/química , Antituberculosos/síntesis química , Proteínas Bacterianas/química , Cristalografía por Rayos X , Inhibidores Enzimáticos/síntesis química , Ligandos , Modelos Moleculares , Estructura Molecular , Oxidorreductasas/química , Bibliotecas de Moléculas Pequeñas/síntesis química , Resonancia por Plasmón de Superficie
12.
Cad. Saúde Pública (Online) ; 34(6): e00033317, 2018. tab
Artículo en Inglés | LILACS | ID: biblio-952410

RESUMEN

The objective of this study was to investigate the prevalence and factors associated with syphilis in homeless men in Central Brazil. It is a cross-sectional study conducted with 481 individuals attending four therapeutic communities between October and December 2015. A structured interview was conducted to collect sociodemographic data and risk factors for syphilis. Rapid/point-of-care and VDRL tests were performed to determine exposure to syphilis and the presence of active syphilis, respectively. Poisson regression analysis was used to verify the risk factors associated with the outcomes investigated. Of the study participants, 10.2% were reactive to the rapid test, and 5.4% had active syphilis. At the multiple regression analysis, schooling (adjusted prevalence ratio - APR: 0.89; p = 0.005), history of genital ulcer (APR: 2.59; p = 0.002), STI history (APR: 1.97; p = 0.042), and sexual intercourse under drug effects (APR: 1.60; p = 0.022) were independent factors associated with lifetime syphilis. Also, history of genital ulcer (APR: 2.19; p = 0.019), STI history (APR: 1.74; p = 0.033) and number of sexual partners in the last year (APR: 1.02; p = 0.044) were associated with active syphilis. The prevalence of syphilis among homeless men was rather high, confirming the vulnerability of this group to this infection. These results emphasize the need for educational intervention, improvement of risk reduction programs, availability of diagnostic tests, especially the rapid test, and treatment.


O estudo teve como objetivo investigar a prevalência da sífilis e fatores associados em homens sem-teto no Centro-oeste do Brasil. A amostra nesse estudo transversal incluiu 481 indivíduos que frequentavam comunidades terapêuticas entre outubro e dezembro de 2015. Uma entrevista estruturada foi usada para coletar dados sociodemográficos e fatores de risco para sífilis. Foram realizados testes rápidos e VDRL para determinar a exposição à sífilis e a presença de sífilis ativa, respectivamente. A análise de regressão de Poisson foi usada para verificar os fatores de risco associados aos desfechos investigados. Entre os participantes, 10,2% foram reativos ao teste rápido e 5,4% tinham sífilis ativa. Na análise de regressão múltipla, a escolaridade (razão de prevalência ajustada - RPA: 0,89; p = 0,005), história de úlcera genital (RPA: 2,59; p = 0,002), história de DST (RPA: 1,97; p = 0,042) e relações sexuais sob o efeito de drogas (RPA: 1,60; p = 0,022) apareceram como fatores independentes associados à história pregressa de sífilis. Além disso, a história de úlcera genital (RPA: 2,19; p = 0,019), história de DST (RPA: 1,74; p = 0,033) e número de parceiros sexuais no último ano (RPA: 1,02; p = 0,044) estiveram associados à sífilis ativa. A prevalência de sífilis em homens sem-teto era bastante elevada, confirmando a vulnerabilidade desse grupo à infecção. Os achados enfatizam a necessidade de intervenções educacionais, melhoria dos programas de redução de risco, disponibilidade de testes diagnósticos (sobretudo o teste rápido) e tratamento adequado.


El objetivo de este estudio fue investigar la prevalencia y los factores asociados con la sífilis en hombres sin techo en el Centro-oeste de Brasil. Se trata de un estudio transversal, llevado a cabo con 481 personas que asistían a cuatro comunidades terapéuticas entre octubre y diciembre de 2015. La entrevista estructurada se realizó con el fin de recabar datos sociodemográficos y factores de riesgo para la sífilis. Se realizaron pruebas de diagnóstico rápido y serológicas para la sífilis (VDRL por sus siglas en inglés) para determinar la exposición a la sífilis y la presencia de sífilis activa, respectivamente. Se usó el análisis por regresión de Poisson para verificar los factores de riesgo asociados con los resultados investigados. Entre los participantes en el estudio, un 10,2% fueron reactivos a las pruebas de diagnóstico rápido, y un 5,4% tenían sífilis activa. En el análisis de regresión múltiple, la escolarización (la razón de prevalencia ajustada - APR: 0,89; p = 0,005), un historial de úlcera genital (APR: 2,59; p = 0,002), un historial de ETS (APR: 1,97; p = 0,042), e intercambios sexuales bajo los efectos de las drogas (APR: 1,60; p = 0,022) fueron factores independientes asociados con la sífilis a lo largo de la vida. Asimismo, un historial de úlcera genital (APR: 2,19; p = 0,019), un historial de ETS (APR: 1,74; p = 0,033) y el número de parejas de índole sexual en el último año (APR: 1,02; p = 0,044) estuvieron asociados con sífilis activa. La prevalencia de sífilis entre los hombres sin techo fue bastante alta, confirmando la vulnerabilidad de este grupo a la infección. Estos resultados enfatizan la necesidad de intervenciones educativas, así como una mejora en los programas de reducción del riesgo, disponibilidad de pruebas de diagnóstico, especialmente pruebas rápidas, y tratamiento.


Asunto(s)
Humanos , Masculino , Adulto , Persona de Mediana Edad , Personas con Mala Vivienda/estadística & datos numéricos , Sífilis/transmisión , Sífilis/epidemiología , Conducta Sexual/estadística & datos numéricos , Factores Socioeconómicos , Brasil/epidemiología , Prevalencia , Estudios Transversales , Análisis de Regresión , Factores de Riesgo , Factores de Edad , Medición de Riesgo , Trastornos Relacionados con Sustancias/complicaciones , Trastornos Relacionados con Sustancias/epidemiología , Conductas de Riesgo para la Salud
13.
Front Pharmacol ; 8: 681, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29018348

RESUMEN

Mycobacterium phenotypic hits are a good reservoir for new chemotypes for the treatment of tuberculosis. However, the absence of defined molecular targets and modes of action could lead to failure in drug development. Therefore, a combination of ligand-based and structure-based chemogenomic approaches followed by biophysical and biochemical validation have been used to identify targets for Mycobacterium tuberculosis phenotypic hits. Our approach identified EthR and InhA as targets for several hits, with some showing dual activity against these proteins. From the 35 predicted EthR inhibitors, eight exhibited an IC50 below 50 µM against M. tuberculosis EthR and three were confirmed to be also simultaneously active against InhA. Further hit validation was performed using X-ray crystallography yielding eight new crystal structures of EthR inhibitors. Although the EthR inhibitors attain their activity against M. tuberculosis by hitting yet undefined targets, these results provide new lead compounds that could be further developed to be used to potentiate the effect of EthA activated pro-drugs, such as ethionamide, thus enhancing their bactericidal effect.

14.
J Med Chem ; 60(19): 8011-8026, 2017 10 12.
Artículo en Inglés | MEDLINE | ID: mdl-28953378

RESUMEN

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.


Asunto(s)
Antituberculosos/síntesis química , Antituberculosos/farmacología , Compuestos de Boro/farmacología , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Compuestos Heterocíclicos con 2 Anillos/farmacología , Leucina-ARNt Ligasa/antagonistas & inhibidores , Mycobacterium tuberculosis/efectos de los fármacos , Animales , Antituberculosos/farmacocinética , Compuestos de Boro/síntesis química , Compuestos de Boro/farmacocinética , Descubrimiento de Drogas , Inhibidores Enzimáticos/farmacocinética , Femenino , Compuestos Heterocíclicos con 2 Anillos/síntesis química , Humanos , Ratones , Ratones Endogámicos C57BL , Mycobacterium tuberculosis/enzimología , Relación Estructura-Actividad , Especificidad por Sustrato
15.
Sci Rep ; 7(1): 9430, 2017 08 25.
Artículo en Inglés | MEDLINE | ID: mdl-28842600

RESUMEN

Drug discovery efforts against the pathogen Mycobacterium tuberculosis (Mtb) have been advanced through phenotypic screens of extensive compound libraries. Such a screen revealed sulfolane 1 and indoline-5-sulfonamides 2 and 3 as potent inhibitors of mycobacterial growth. Optimization in the sulfolane series led to compound 4, which has proven activity in an in vivo murine model of Mtb infection. Here we identify the target and mode of inhibition of these compounds based on whole genome sequencing of spontaneous resistant mutants, which identified mutations locating to the essential α- and ß-subunits of tryptophan synthase. Over-expression studies confirmed tryptophan synthase as the biological target. Biochemical techniques probed the mechanism of inhibition, revealing the mutant enzyme complex incurs a fitness cost but does not prevent inhibitor binding. Mapping of the resistance conferring mutations onto a low-resolution crystal structure of Mtb tryptophan synthase showed they locate to the interface between the α- and ß-subunits. The discovery of anti-tubercular agents inhibiting tryptophan synthase highlights the therapeutic potential of this enzyme and draws attention to the prospect of other amino acid biosynthetic pathways as future Mtb drug targets.


Asunto(s)
Antituberculosos/farmacología , Proteínas Bacterianas/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Mycobacterium/efectos de los fármacos , Mycobacterium/enzimología , Triptófano Sintasa/antagonistas & inhibidores , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Farmacorresistencia Bacteriana , Humanos , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Mutación , Mycobacterium/genética , Conformación Proteica , Relación Estructura-Actividad , Tiofenos/farmacología , Triptófano Sintasa/química , Triptófano Sintasa/metabolismo
16.
ACS Infect Dis ; 3(6): 428-437, 2017 06 09.
Artículo en Inglés | MEDLINE | ID: mdl-28475832

RESUMEN

Despite its great potential, the target-based approach has been mostly unsuccessful in tuberculosis drug discovery, while whole cell phenotypic screening has delivered several active compounds. However, for many of these hits, the cellular target has not yet been identified, thus preventing further target-based optimization of the compounds. In this context, the newly validated drug target CTP synthetase PyrG was exploited to assess a target-based approach of already known, but untargeted, antimycobacterial compounds. To this purpose the publically available GlaxoSmithKline antimycobacterial compound set was assayed, uncovering a series of 4-(pyridin-2-yl)thiazole derivatives which efficiently inhibit the Mycobacterium tuberculosis PyrG enzyme activity, one of them showing low activity against the human CTP synthetase. The three best compounds were ATP binding site competitive inhibitors, with Ki values ranging from 3 to 20 µM, but did not show any activity against a small panel of different prokaryotic and eukaryotic kinases, thus demonstrating specificity for the CTP synthetases. Metabolic labeling experiments demonstrated that the compounds directly interfere not only with CTP biosynthesis, but also with other CTP dependent biochemical pathways, such as lipid biosynthesis. Moreover, using a M. tuberculosis pyrG conditional knock-down strain, it was shown that the activity of two compounds is dependent on the intracellular concentration of the CTP synthetase. All these results strongly suggest a role of PyrG as a target of these compounds, thus strengthening the value of this kind of approach for the identification of new scaffolds for drug development.


Asunto(s)
Antituberculosos/farmacología , Proteínas Bacterianas/antagonistas & inhibidores , Ligasas de Carbono-Nitrógeno/antagonistas & inhibidores , Mycobacterium tuberculosis/efectos de los fármacos , Piridinas/farmacología , Tiazoles/farmacología , Adenosina Trifosfato/química , Adenosina Trifosfato/metabolismo , Antituberculosos/química , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Unión Competitiva , Ligasas de Carbono-Nitrógeno/química , Ligasas de Carbono-Nitrógeno/genética , Ligasas de Carbono-Nitrógeno/metabolismo , Descubrimiento de Drogas , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Expresión Génica , Ensayos Analíticos de Alto Rendimiento , Cinética , Lípidos/antagonistas & inhibidores , Lípidos/biosíntesis , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Simulación del Acoplamiento Molecular , Mycobacterium tuberculosis/enzimología , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/crecimiento & desarrollo , Unión Proteica , Piridinas/química , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacología , Relación Estructura-Actividad , Tiazoles/química
17.
Sci Rep ; 6: 38986, 2016 12 16.
Artículo en Inglés | MEDLINE | ID: mdl-27982051

RESUMEN

High-throughput phenotypic screens have re-emerged as screening tools in antibiotic discovery. The advent of such technologies has rapidly accelerated the identification of 'hit' compounds. A pre-requisite to medicinal chemistry optimisation programmes required to improve the drug-like properties of a 'hit' molecule is identification of its mode of action. Herein, we have combined phenotypic screening with a biased target-specific screen. The inosine monophosphate dehydrogenase (IMPDH) protein GuaB2 has been identified as a drugable target in Mycobacterium tuberculosis, however previously identified compounds lack the desired characteristics necessary for further development into lead-like molecules. This study has identified 7 new chemical series from a high-throughput resistance-based phenotypic screen using Mycobacterium bovis BCG over-expressing GuaB2. Hit compounds were identified in a single shot high-throughput screen, validated by dose response and subjected to further biochemical analysis. The compounds were also assessed using molecular docking experiments, providing a platform for their further optimisation using medicinal chemistry. This work demonstrates the versatility and potential of GuaB2 as an anti-tubercular drug target.


Asunto(s)
Antituberculosos/farmacología , Proteínas Bacterianas/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , IMP Deshidrogenasa/antagonistas & inhibidores , Mycobacterium tuberculosis/enzimología , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Evaluación Preclínica de Medicamentos , IMP Deshidrogenasa/genética , IMP Deshidrogenasa/metabolismo , Mycobacterium bovis/enzimología , Mycobacterium bovis/genética , Mycobacterium tuberculosis/genética
18.
Sci Rep ; 6: 34293, 2016 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-27678056

RESUMEN

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.
Nat Commun ; 7: 12581, 2016 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-27581223

RESUMEN

Phenotypic screens for bactericidal compounds are starting to yield promising hits against tuberculosis. In this regard, whole-genome sequencing of spontaneous resistant mutants generated against an indazole sulfonamide (GSK3011724A) identifies several specific single-nucleotide polymorphisms in the essential Mycobacterium tuberculosis ß-ketoacyl synthase (kas) A gene. Here, this genomic-based target assignment is confirmed by biochemical assays, chemical proteomics and structural resolution of a KasA-GSK3011724A complex by X-ray crystallography. Finally, M. tuberculosis GSK3011724A-resistant mutants increase the in vitro minimum inhibitory concentration and the in vivo 99% effective dose in mice, establishing in vitro and in vivo target engagement. Surprisingly, the lack of target engagement of the related ß-ketoacyl synthases (FabH and KasB) suggests a different mode of inhibition when compared with other Kas inhibitors of fatty acid biosynthesis in bacteria. These results clearly identify KasA as the biological target of GSK3011724A and validate this enzyme for further drug discovery efforts against tuberculosis.


Asunto(s)
3-Oxoacil-(Proteína Transportadora de Acil) Sintasa/antagonistas & inhibidores , 3-Oxoacil-(Proteína Transportadora de Acil) Sintasa/genética , Antituberculosos/farmacología , Proteínas Bacterianas/antagonistas & inhibidores , Proteínas Bacterianas/genética , Indazoles/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Sulfonamidas/farmacología , Tuberculosis Pulmonar/tratamiento farmacológico , Animales , Farmacorresistencia Bacteriana/genética , Femenino , Ratones , Ratones Endogámicos C57BL , Pruebas de Sensibilidad Microbiana , Mycobacterium tuberculosis/genética , Polimorfismo de Nucleótido Simple/genética , Tuberculosis Pulmonar/microbiología , Tuberculosis Pulmonar/prevención & control
20.
Antimicrob Agents Chemother ; 60(10): 6271-80, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27503647

RESUMEN

The recent development and spread of extensively drug-resistant and totally drug-resistant resistant (TDR) strains of Mycobacterium tuberculosis highlight the need for new antitubercular drugs. Protein synthesis inhibitors have played an important role in the treatment of tuberculosis (TB) starting with the inclusion of streptomycin in the first combination therapies. Although parenteral aminoglycosides are a key component of therapy for multidrug-resistant TB, the oxazolidinone linezolid is the only orally available protein synthesis inhibitor that is effective against TB. Here, we show that small-molecule inhibitors of aminoacyl-tRNA synthetases (AARSs), which are known to be excellent antibacterial protein synthesis targets, are orally bioavailable and effective against M. tuberculosis in TB mouse infection models. We applied the oxaborole tRNA-trapping (OBORT) mechanism, which was first developed to target fungal cytoplasmic leucyl-tRNA synthetase (LeuRS), to M. tuberculosis LeuRS. X-ray crystallography was used to guide the design of LeuRS inhibitors that have good biochemical potency and excellent whole-cell activity against M. tuberculosis Importantly, their good oral bioavailability translates into in vivo efficacy in both the acute and chronic mouse models of TB with potency comparable to that of the frontline drug isoniazid.


Asunto(s)
Antituberculosos/farmacología , Leucina-ARNt Ligasa/antagonistas & inhibidores , Mycobacterium tuberculosis/efectos de los fármacos , Inhibidores de la Síntesis de la Proteína/farmacología , Administración Oral , Animales , Antituberculosos/administración & dosificación , Antituberculosos/química , Antituberculosos/farmacocinética , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos/métodos , Femenino , Humanos , Leucina-ARNt Ligasa/química , Leucina-ARNt Ligasa/genética , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Endogámicos , Pruebas de Sensibilidad Microbiana , Mycobacterium smegmatis/efectos de los fármacos , Mycobacterium smegmatis/genética , Mycobacterium tuberculosis/genética , Inhibidores de la Síntesis de la Proteína/administración & dosificación , Inhibidores de la Síntesis de la Proteína/química , Inhibidores de la Síntesis de la Proteína/farmacocinética , Relación Estructura-Actividad , Tuberculosis/tratamiento farmacológico , Células Vero
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA