3,5-Dinitrobenzylsulfanyl tetrazoles and 1,3,4-oxadiazoles, previously identified as having high in vitro activities against both replicating and nonreplicating mycobacteria and favorable cytotoxicity and genotoxicity profiles were investigated. First we demonstrated that these compounds act in a deazaflavin-dependent nitroreduction pathway and thus require a nitro group for their activity. Second, we confirmed the necessity of both nitro groups for antimycobacterial activity through extensive structure-activity relationship studies using 32 structural types of analogues, each in a five-membered series. Only the analogues with shifted nitro groups, namely, 2,5-dinitrobenzylsulfanyl oxadiazoles and tetrazoles, maintained high antimycobacterial activity but in this case mainly as a result of DprE1 inhibition. However, these analogues also showed increased toxicity to the mammalian cell line. Thus, both nitro groups in 3,5-dinitrobenzylsulfanyl-containing antimycobacterial agents remain essential for their high efficacy, and further efforts should be directed at finding ways to address the possible toxicity and solubility issues, for example, by targeted delivery.
- MeSH
- antituberkulotika farmakologie chemie MeSH
- mikrobiální testy citlivosti MeSH
- Mycobacterium tuberculosis * MeSH
- nitroreduktasy MeSH
- oxadiazoly farmakologie chemie MeSH
- savci MeSH
- tetrazoly farmakologie chemie MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Phenotypic screening of an in-house library of small molecule purine derivatives against Mycobacterium tuberculosis (Mtb) led to the identification of 2-morpholino-7-(naphthalen-2-ylmethyl)-1,7-dihydro-6H-purin-6-one 10 as a potent antimycobacterial agent with MIC99 of 4 μM. Thorough structure-activity relationship studies revealed the importance of 7-(naphthalen-2-ylmethyl) substitution for antimycobacterial activity, yet opened the possibility of structural modifications at positions 2 and 6 of the purine core. As the result, optimized analogues with 6-amino or ethylamino substitution 56 and 64, respectively, were developed. These compounds showed strong in vitro antimycobacterial activity with MIC of 1 μM against Mtb H37Rv and against several clinically isolated drug-resistant strains, had limited toxicity to mammalian cell lines, medium clearance with respect to phase I metabolic deactivation (27 and 16.8 μL/min/mg), sufficient aqueous solubility (>90 μM) and high plasma stability. Interestingly, investigated purines, including compounds 56 and 64, lacked activity against a panel of Gram-negative and Gram-positive bacterial strains, indicating a specific mycobacterial molecular target. To investigate the mechanism of action, Mtb mutants resistant to hit compound 10 were isolated and their genomes were sequenced. Mutations were found in dprE1 (Rv3790), which encodes decaprenylphosphoryl-β-d-ribose oxidase DprE1, enzyme essential for the biosynthesis of arabinose, a vital component of the mycobacterial cell wall. Inhibition of DprE1 by 2,6-disubstituted 7-(naphthalen-2-ylmethyl)-7H-purines was proved using radiolabelling experiments in Mtb H37Rv in vitro. Finally, structure-binding relationships between selected purines and DprE1 using molecular modeling studies in tandem with molecular dynamic simulations revealed the key structural features for effective drug-target interaction.
- MeSH
- alkoholoxidoreduktasy chemie MeSH
- antituberkulotika * chemie MeSH
- bakteriální proteiny metabolismus MeSH
- Mycobacterium tuberculosis * MeSH
- puriny farmakologie MeSH
- savci metabolismus MeSH
- simulace molekulární dynamiky MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Latent Mycobacterium tuberculosis infection presents one of the largest challenges for tuberculosis control and novel antimycobacterial drug development. A series of pyrano[3,2-b]indolone-based compounds was designed and synthesized via an original eight-step scheme. The synthesized compounds were evaluated for their in vitro activity against M. tuberculosis strains H37Rv and streptomycin-starved 18b (SS18b), representing models for replicating and nonreplicating mycobacteria, respectively. Compound 10a exhibited good activity with MIC99 values of 0.3 and 0.4 μg/mL against H37Rv and SS18b, respectively, as well as low toxicity, acceptable intracellular activity, and satisfactory metabolic stability and was selected as the lead compound for further studies. An analysis of 10a-resistant M. bovis mutants disclosed a cross-resistance with pretomanid and altered relative amounts of different forms of cofactor F420 in these strains. Complementation experiments showed that F420-dependent glucose-6-phosphate dehydrogenase and the synthesis of mature F420 were important for 10a activity. Overall these studies revealed 10a to be a prodrug that is activated by an unknown F420-dependent enzyme in mycobacteria.
- MeSH
- antituberkulotika farmakologie MeSH
- latentní tuberkulóza * MeSH
- lidé MeSH
- Mycobacterium tuberculosis * genetika MeSH
- tuberkulóza * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Mycobacterium tuberculosis, one of the deadliest pathogens in human history, is distinguished by a unique, multilayered cell wall, which offers the bacterium a high level of protection from the attacks of the host immune system. The primary structure of the cell wall core, composed of covalently linked peptidoglycan, branched heteropolysaccharide arabinogalactan, and mycolic acids, is well known, and numerous enzymes involved in the biosynthesis of its components are characterized. The cell wall biogenesis takes place at both cytoplasmic and periplasmic faces of the plasma membrane, and only recently some of the specific transport systems translocating the metabolic intermediates between these two compartments have been characterized [M. Jackson, C. M. Stevens, L. Zhang, H. I. Zgurskaya, M. Niederweis, Chem. Rev., 10.1021/acs.chemrev.0c00869 (2020)]. In this work, we use CRISPR interference methodology in Mycobacterium smegmatis to functionally characterize an ATP-binding cassette (ABC) transporter involved in the translocation of galactan precursors across the plasma membrane. We show that genetic knockdown of the transmembrane subunit of the transporter results in severe morphological changes and the accumulation of an aberrantly long galactan precursor. Based on similarities with structures and functions of specific O-antigen ABC transporters of gram-negative bacteria [C. Whitfield, D. M. Williams, S. D. Kelly, J. Biol. Chem. 295, 10593-10609 (2020)], we propose a model for coupled synthesis and export of the galactan polymer precursor in mycobacteria.
We report herein the discovery of 3,5-dinitrophenyl 1,2,4-triazoles with excellent and selective antimycobacterial activities against Mycobacterium tuberculosis strains, including clinically isolated multidrug-resistant strains. Thorough structure-activity relationship studies of 3,5-dinitrophenyl-containing 1,2,4-triazoles and their trifluoromethyl analogues revealed the key role of the position of the 3,5-dinitrophenyl fragment in the antitubercular efficiency. Among the prepared compounds, the highest in vitro antimycobacterial activities against M. tuberculosis H37Rv and against seven clinically isolated multidrug-resistant strains of M. tuberculosis were found with S-substituted 4-alkyl-5-(3,5-dinitrophenyl)-4H-1,2,4-triazole-3-thiols and their 3-nitro-5-(trifluoromethyl)phenyl analogues. The minimum inhibitory concentrations of these compounds reached 0.03 μM, which is superior to all the current first-line anti-tuberculosis drugs. Furthermore, almost all compounds with excellent antimycobacterial activities exhibited very low in vitro cytotoxicities against two proliferating mammalian cell lines. The docking study indicated that these compounds acted as the inhibitors of decaprenylphosphoryl-β-d-ribofuranose 2'-oxidase enzyme, which was experimentally confirmed by two independent radiolabeling experiments.
- MeSH
- alkoholoxidoreduktasy antagonisté a inhibitory metabolismus MeSH
- antituberkulotika chemická syntéza chemie farmakologie MeSH
- bakteriální proteiny antagonisté a inhibitory metabolismus MeSH
- dinitrobenzeny chemická syntéza chemie farmakologie MeSH
- fluorované uhlovodíky chemická syntéza chemie farmakologie MeSH
- molekulární modely MeSH
- molekulární struktura MeSH
- Mycobacterium tuberculosis účinky léků enzymologie MeSH
- triazoly chemická syntéza chemie farmakologie MeSH
- vyvíjení léků * MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The development of novel drugs is essential for the treatment of tuberculosis and other mycobacterial infections in future. A series of N-alkyl-2-isonicotinoylhydrazine-1-carboxamides was synthesized from isoniazid (INH) and then cyclized to N-alkyl-5-(pyridin-4-yl)-1,3,4-oxadiazole-2-amines. All derivatives were characterised spectroscopically. The compounds were screened for their in vitro antimycobacterial activity against susceptible and multidrug-resistant Mycobacterium tuberculosis (Mtb.) and nontuberculous mycobacteria (NTM; M. avium, M. kansasii). The most active carboxamides were substituted by a short n-alkyl, their activity was comparable to INH with minimum inhibitory concentrations (MICs) against Mtb. of 0.5-2 μM. Moreover, they are non-toxic for HepG2, and some of them are highly active against INH-resistant NTM (MICs ≥4 μM). Their cyclization to 1,3,4-oxadiazoles did not increase the activity. The experimentally proved mechanism of action of 2-isonicotinoylhydrazine-1-carboxamides consists of the inhibition of enoyl-ACP reductase (InhA) in a way similar to INH, which is blocking the biosynthesis of mycolic acids. N-Dodecyl-5-(pyridin-4-yl)-1,3,4-oxadiazol-2-amine as the most efficacious oxadiazole inhibits growth of both susceptible and drug-resistant Mtb. strains with uniform MIC values of 4-8 μM with no cross-resistance to antitubercular drugs including INH. The mechanism of action is not elucidated but it is different from INH. Obtained results qualify these promising derivatives for further investigation.
- MeSH
- antituberkulotika chemická syntéza chemie farmakologie MeSH
- bakteriální léková rezistence MeSH
- buňky Hep G2 MeSH
- isoniazid analogy a deriváty chemická syntéza farmakologie MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- Mycobacterium tuberculosis účinky léků MeSH
- oxadiazoly chemická syntéza chemie farmakologie MeSH
- tuberkulóza farmakoterapie mikrobiologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Herein, we report the discovery and structure-activity relationships of 5-substituted-2-[(3,5-dinitrobenzyl)sulfanyl]-1,3,4-oxadiazoles and 1,3,4-thiadiazoles as a new class of antituberculosis agents. The majority of these compounds exhibited outstanding in vitro activity against Mycobacterium tuberculosis CNCTC My 331/88 and six multidrug-resistant clinically isolated strains of M. tuberculosis, with minimum inhibitory concentration values as low as 0.03 μM (0.011-0.026 μg/mL). The investigated compounds had a highly selective antimycobacterial effect because they showed no activity against the other bacteria or fungi tested in this study. Furthermore, the investigated compounds exhibited low in vitro toxicities in four proliferating mammalian cell lines and in isolated primary human hepatocytes. Several in vitro genotoxicity assays indicated that the selected compounds have no mutagenic activity. The oxadiazole and thiadiazole derivatives with the most favorable activity/toxicity profiles also showed potency comparable to that of rifampicin against the nonreplicating streptomycin-starved M. tuberculosis 18b-Lux strain, and therefore, these derivatives, are of particular interest.
- MeSH
- antituberkulotika chemická syntéza farmakologie toxicita MeSH
- Bacteria účinky léků MeSH
- buněčné linie MeSH
- houby účinky léků MeSH
- latentní tuberkulóza farmakoterapie mikrobiologie MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- mikrozomy metabolismus MeSH
- mnohočetná bakteriální léková rezistence MeSH
- mutageny toxicita MeSH
- Mycobacterium tuberculosis účinky léků MeSH
- oxazoly chemická syntéza farmakologie MeSH
- primární buněčná kultura MeSH
- racionální návrh léčiv MeSH
- rifampin farmakologie MeSH
- thiadiazoly chemická syntéza farmakologie MeSH
- viabilita buněk účinky léků MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- dezinfekce metody normy MeSH
- diabetes mellitus 2. typu diagnóza krev MeSH
- glukózový toleranční test metody přístrojové vybavení využití MeSH
- klinický obraz nemoci MeSH
- krevní glukóza izolace a purifikace MeSH
- lékárny využití MeSH
- lidé MeSH
- nebezpečný odpad zákonodárství a právo MeSH
- selfmonitoring glykemie metody využití MeSH
- společnosti farmaceutické využití MeSH
- vládní programy organizace a řízení využití zákonodárství a právo MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- směrnice pro lékařskou praxi MeSH
- MeSH
- domácí ošetřování metody MeSH
- hypertenze diagnóza farmakoterapie prevence a kontrola MeSH
- krevní tlak účinky léků MeSH
- lidé MeSH
- měření krevního tlaku metody využití MeSH
- rizikové faktory MeSH
- samovyšetření metody MeSH
- senioři nad 80 let MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- Publikační typ
- kazuistiky MeSH
- MeSH
- benzodiazepiny aplikace a dávkování škodlivé účinky toxicita MeSH
- hypnotika a sedativa aplikace a dávkování škodlivé účinky toxicita MeSH
- lidé středního věku MeSH
- lidé MeSH
- poruchy spojené s užíváním psychoaktivních látek diagnóza terapie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
