RESUMO
The identification of chemical starting points for the development of molecular glues is challenging. Here, we employed fragment screening and identified an allosteric stabilizer of the complex between 14-3-3 and a TAZ-derived peptide. The fragment binds preferentially to the 14-3-3/TAZ peptide complex and shows moderate stabilization in differential scanning fluorimetry and microscale thermophoresis. The binding site of the fragment was predicted by molecular dynamics calculations to be distant from the 14-3-3/TAZ peptide interface, located between helices 8 and 9 of the 14-3-3 protein. This site was confirmed by nuclear magnetic resonance and X-ray protein crystallography, revealing the first example of an allosteric stabilizer for 14-3-3 protein-protein interactions.
RESUMO
The European Network for diagnosis and treatment of antibiotic-resistant bacterial infections-EURESTOP COST Action CA21145 focuses on tackling the burden of antimicrobial resistance (AMR) and has gathered many members working on photodynamic approaches. This European consortium is presented here in the One Health context, to highlight the potential of antimicrobial photodynamic therapy (aPDT) in the fight against AMR.
Assuntos
Anti-Infecciosos , Infecções Bacterianas , Fotoquimioterapia , Humanos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bactérias , Anti-Infecciosos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/microbiologia , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêuticoRESUMO
Multidrug-resistant (MDR) pathogens are severely impacting our ability to successfully treat common infections. Here we report the synthesis of a panel of adarotene-related retinoids showing potent antimicrobial activity on Staphylococcus aureus strains (including multidrug-resistant ones). Fluorescence and molecular dynamic studies confirmed that the adarotene analogues were able to induce conformational changes and disfunctions to the cell membrane, perturbing the permeability of the phospholipid bilayer. Since the major obstacle for developing retinoids is their potential cytotoxicity, a selected candidate was further investigated to evaluate its activity on a panel of human cell lines. The compound was found to be well tolerated, with IC50 5-15-fold higher than the MIC on S. aureus strains. Furthermore, the adarotene analogue had a good pharmacokinetic profile, reaching a plasma concentration of about 6 µM after 0.5 h after administration (150 mg/kg), at least twice the MIC observed against various bacterial strains. Moreover, it was demonstrated that the compound potentiated the growth-inhibitory effect of the poorly bioavailable rifaximin, when used in combination. Overall, the collected data pave the way for the development of synthetic retinoids as potential therapeutics for hard-to-treat infectious diseases caused by antibiotic-resistant Gram-positive pathogens.
Assuntos
Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Humanos , Staphylococcus aureus , Antibacterianos , Retinoides/farmacologia , Infecções Estafilocócicas/tratamento farmacológico , Testes de Sensibilidade MicrobianaRESUMO
The influenza A virus nonstructural protein 1 (NS1), which is crucial for viral replication and immune evasion, has been identified as a significant drug target with substantial potential to contribute to the fight against influenza. The emergence of drug-resistant influenza A virus strains highlights the urgent need for novel therapeutics. This study proposes a combined theoretical criterion for the virtual screening of molecular libraries to identify candidate NS1 inhibitors. By applying the criterion to the ZINC Natural Product database, followed by ligand-based virtual screening and molecular docking, we proposed the most promising candidate as a potential NS1 inhibitor. Subsequently, the selected natural compound was experimentally evaluated, revealing measurable virus replication inhibition activity in cell culture. This approach offers a promising avenue for developing novel anti-influenza agents targeting the NS1 protein.
Assuntos
Antivirais , Produtos Biológicos , Simulação de Acoplamento Molecular , Proteínas não Estruturais Virais , Replicação Viral , Antivirais/farmacologia , Antivirais/química , Humanos , Produtos Biológicos/farmacologia , Produtos Biológicos/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Proteínas não Estruturais Virais/metabolismo , Replicação Viral/efeitos dos fármacos , Influenza Humana/tratamento farmacológico , Influenza Humana/virologia , Vírus da Influenza A/efeitos dos fármacos , Animais , Células Madin Darby de Rim Canino , CãesRESUMO
Natural products (NPs) are highly profitable pharmacological tools due to their chemical diversity and ability to modulate biological systems. Accessing new chemical entities while retaining the biological relevance of natural chemotypes is a fundamental goal in the design of novel bioactive compounds. Notably, NPs have played a crucial role in understanding Hedgehog (HH) signalling and its pharmacological modulation in anticancer therapy. However, HH antagonists developed so far have shown several limitations, thus growing interest in the design of second-generation HH inhibitors. Through smart manipulation of the NPs core-scaffold, unprecedented and intriguing architectures have been achieved following different design strategies. This study reports the rational design and synthesis of a first and second generation of anthraquinone-based hybrids by combining the rhein scaffold with variously substituted piperazine nuclei that are structurally similar to the active portion of known SMO antagonists, the main transducer of the HH pathway. A thorough functional and biological investigation identified RH2_2 and RH2_6 rhein-based hybrids as valuable candidates for HH inhibition through SMO antagonism, with the consequent suppression of HH-dependent tumour growth. These findings also corroborated the successful application of the NPs-based hybrid design strategy in the development of novel NP-based SMO antagonists.
Assuntos
Antineoplásicos , Neoplasias , Humanos , Receptor Smoothened/uso terapêutico , Proteínas Hedgehog/metabolismo , Proteínas Hedgehog/uso terapêutico , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Antraquinonas/farmacologia , Receptores Acoplados a Proteínas G/metabolismoRESUMO
Ubiquitin-like containing PHD and RING finger domain 1 (UHRF1) is a nuclear multi-domain protein overexpressed in numerous human cancer types. We previously disclosed the anthraquinone derivative UM63 that inhibits UHRF1-SRA domain base-flipping activity, although having DNA intercalating properties. Herein, based on the UM63 structure, new UHRF1-SRA inhibitors were identified through a multidisciplinary approach, combining molecular modelling, biophysical assays, molecular and cell biology experiments. We identified AMSA2 and MPB7, that inhibit UHRF1-SRA mediated base flipping at low micromolar concentrations, but do not intercalate into DNA, which is a key advantage over UM63. These molecules prevent UHRF1/DNMT1 interaction at replication forks and decrease the overall DNA methylation in cells. Moreover, both compounds specifically induce cell death in numerous cancer cell lines, displaying marginal effect on non-cancer cells, as they preferentially affect cells with high level of UHRF1. Overall, these two compounds are promising leads for the development of anti-cancer drugs targeting UHRF1.
Assuntos
Proteínas Estimuladoras de Ligação a CCAAT , Neoplasias , Humanos , Proteínas Estimuladoras de Ligação a CCAAT/química , Proteínas Estimuladoras de Ligação a CCAAT/genética , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Metilação de DNA , DNA/química , Modelos Moleculares , Neoplasias/genéticaRESUMO
Aiming to identify highly effective and selective G-quadruplex ligands as anticancer candidates, five natural compounds were investigated here, i.e., the alkaloids Canadine, D-Glaucine and Dicentrine, as well as the flavonoids Deguelin and Millettone, selected as analogs of compounds previously identified as promising G-quadruplex-targeting ligands. A preliminary screening with the G-quadruplex on the Controlled Pore Glass assay proved that, among the investigated compounds, Dicentrine is the most effective ligand of telomeric and oncogenic G-quadruplexes, also showing good G-quadruplex vs. duplex selectivity. In-depth studies in solution demonstrated the ability of Dicentrine to thermally stabilize telomeric and oncogenic G-quadruplexes without affecting the control duplex. Interestingly, it showed higher affinity for the investigated G-quadruplex structures over the control duplex (Kb~106 vs. 105 M-1), with some preference for the telomeric over the oncogenic G-quadruplex model. Molecular dynamics simulations indicated that Dicentrine preferentially binds the G-quadruplex groove or the outer G-tetrad for the telomeric and oncogenic G-quadruplexes, respectively. Finally, biological assays proved that Dicentrine is highly effective in promoting potent and selective anticancer activity by inducing cell cycle arrest through apoptosis, preferentially targeting G-quadruplex structures localized at telomeres. Taken together, these data validate Dicentrine as a putative anticancer candidate drug selectively targeting cancer-related G-quadruplex structures.
Assuntos
Antineoplásicos , Quadruplex G , Neoplasias , Humanos , Ligantes , Simulação de Dinâmica Molecular , Antineoplásicos/farmacologia , Telômero/metabolismoRESUMO
BACKGROUND AND AIMS: Oxidative stress plays a key role in the development of metabolic complications associated with obesity, including insulin resistance and the most common chronic liver disease worldwide, nonalcoholic fatty liver disease. We have recently discovered that the microRNA miR-144 regulates protein levels of the master mediator of the antioxidant response, nuclear factor erythroid 2-related factor 2 (NRF2). On miR-144 silencing, the expression of NRF2 target genes was significantly upregulated, suggesting that miR-144 controls NRF2 at the level of both protein expression and activity. Here we explored a mechanism whereby hepatic miR-144 inhibited NRF2 activity upon obesity via the regulation of the tricarboxylic acid (TCA) metabolite, fumarate, a potent activator of NRF2. METHODS: We performed transcriptomic analysis in liver macrophages (LMs) of obese mice and identified the immuno-responsive gene 1 (Irg1) as a target of miR-144. IRG1 catalyzes the production of a TCA derivative, itaconate, an inhibitor of succinate dehydrogenase (SDH). TCA enzyme activities and kinetics were analyzed after miR-144 silencing in obese mice and human liver organoids using single-cell activity assays in situ and molecular dynamic simulations. RESULTS: Increased levels of miR-144 in obesity were associated with reduced expression of Irg1, which was restored on miR-144 silencing in vitro and in vivo. Furthermore, miR-144 overexpression reduces Irg1 expression and the production of itaconate in vitro. In alignment with the reduction in IRG1 levels and itaconate production, we observed an upregulation of SDH activity during obesity. Surprisingly, however, fumarate hydratase (FH) activity was also upregulated in obese livers, leading to the depletion of its substrate fumarate. miR-144 silencing selectively reduced the activities of both SDH and FH resulting in the accumulation of their related substrates succinate and fumarate. Moreover, molecular dynamics analyses revealed the potential role of itaconate as a competitive inhibitor of not only SDH but also FH. Combined, these results demonstrate that silencing of miR-144 inhibits the activity of NRF2 through decreased fumarate production in obesity. CONCLUSIONS: Herein we unravel a novel mechanism whereby miR-144 inhibits NRF2 activity through the consumption of fumarate by activation of FH. Our study demonstrates that hepatic miR-144 triggers a hyperactive FH in the TCA cycle leading to an impaired antioxidant response in obesity.
Assuntos
Fígado Gorduroso/enzimologia , Fumarato Hidratase/metabolismo , Resistência à Insulina , Fígado/enzimologia , Macrófagos/enzimologia , MicroRNAs/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Obesidade/enzimologia , Animais , Carboxiliases/genética , Carboxiliases/metabolismo , Ciclo do Ácido Cítrico , Modelos Animais de Doenças , Fígado Gorduroso/genética , Fumarato Hidratase/genética , Fumaratos/metabolismo , Humanos , Hidroliases/genética , Hidroliases/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , Fator 2 Relacionado a NF-E2/genética , Obesidade/genética , Estresse Oxidativo , Células RAW 264.7 , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Succinatos/metabolismoRESUMO
The disordered tubulin C-terminal tail (CTT), which possesses a higher degree of heterogeneity, is the target for the interaction of many proteins and cellular components. Compared to the seven well-described binding sites of microtubule-targeting agents (MTAs) that localize on the globular tubulin core, tubulin CTT is far less explored. Therefore, tubulin CTT can be regarded as a novel site for the development of MTAs with distinct biochemical and cell biological properties. Here, we designed and synthesized linear and cyclic peptides containing multiple arginines (RRR), which are complementary to multiple acidic residues in tubulin CTT. Some of them showed moderate induction and promotion of tubulin polymerization. The most potent macrocyclic compound 1f was found to bind to tubulin CTT and thus exert its bioactivity. Such RRR containing compounds represent a starting point for the discovery of tubulin CTT-targeting agents with therapeutic potential.
Assuntos
Antineoplásicos , Tubulina (Proteína) , Tubulina (Proteína)/metabolismo , Microtúbulos/metabolismo , Antineoplásicos/farmacologia , Sítios de Ligação , Moduladores de Tubulina/farmacologia , Moduladores de Tubulina/metabolismoRESUMO
N-terminal P23H opsin mutation accounts for most of retinitis pigmentosa (RP) cases. P23H functions and folding can be rescued by small chaperone ligands, which contributes to validate mutant opsin as a suitable target for pharmacological treatment of RP. However, the lack of structural details on P23H mutant opsin strongly impairs drug design, and new chemotypes of effective chaperones of P23H opsin are in high demand. Here, a computational-boosted workflow combining homology modeling with molecular dynamics (MD) simulations and virtual screening was used to select putative P23H opsin chaperones among different libraries through a structure-based approach. In vitro studies corroborated the reliability of the structural model generated in this work and identified a number of novel chemotypes of safe and effective chaperones able to promote P23H opsin trafficking to the outer cell membrane.
Assuntos
Opsinas , Retinose Pigmentar , Humanos , Opsinas/genética , Reprodutibilidade dos Testes , Opsinas de Bastonetes/química , Opsinas de Bastonetes/genética , Opsinas de Bastonetes/metabolismo , Retinose Pigmentar/tratamento farmacológico , Retinose Pigmentar/genética , Retinose Pigmentar/metabolismo , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Chaperonas Moleculares/uso terapêuticoRESUMO
The Bcr-Abl tyrosine kinase (TK) is the molecular hallmark of chronic myeloid leukemia (CML). Src is another TK kinase whose involvement in CML was widely demonstrated. Small molecules active as dual Src/Bcr-Abl inhibitors emerged as effective targeted therapies for CML and a few compounds are currently in clinical use. In this study, we applied a target-oriented approach to identify a family of pyrazolo[3,4-d]pyrimidines as dual Src/Bcr-Abl inhibitors as anti-leukemia agents. Considering the high homology between Src and Bcr-Abl, in-house Src inhibitors 8a-l and new analogue compounds 9a-n were screened as dual Src/Bcr-Abl inhibitors. The antiproliferative activity on K562 CML cells and the ADME profile were determined for the most promising compounds. Molecular modeling studies elucidated the binding mode of the inhibitors into the Bcr-Abl (wt) catalytic pocket. Compounds 8j and 8k showed nanomolar activities in enzymatic and cellular assays, together with favorable ADME properties, emerging as promising candidates for CML therapy. Finally, derivatives 9j and 9k, emerging as valuable inhibitors of the most aggressive Bcr-Abl mutation, T315I, constitute a good starting point in the search for compounds able to treat drug-resistant forms of CML. Overall, this study allowed us to identify more potent compounds than those previously reported by the group, marking a step forward in searching for new antileukemic agents.
Assuntos
Antineoplásicos , Leucemia Mielogênica Crônica BCR-ABL Positiva , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Benzamidas/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Proteínas de Fusão bcr-abl , Humanos , Mesilato de Imatinib , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Piperazinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Pirimidinas/químicaRESUMO
Mutations in the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) protein lead to persistent lung bacterial infections, mainly due to Pseudomonas aeruginosa, causing loss of respiratory function and finally death of people affected by CF. Unfortunately, even in the era of CFTR modulation therapies, management of pulmonary infections in CF remains highly challenging especially for patients with advanced stages of lung disease. Recently, we identified antimicrobial peptides (AMPs), namely Esc peptides, with potent antipseudomonal activity. In this study, by means of electrophysiological techniques and computational studies we discovered their ability to increase the CFTR-controlled ion currents, by direct interaction with the F508del-CFTR mutant. Remarkably, this property was not explored previously with any AMPs or peptides in general. More interestingly, in contrast with clinically used CFTR modulators, Esc peptides would give particular benefit to CF patients by combining their capability to eradicate lung infections and to act as promoters of airway wound repair with their ability to ameliorate the activity of the channel with conductance defects. Overall, our findings not only highlighted Esc peptides as the first characterized AMPs with a novel property, that is the potentiator activity of CFTR, but also paved the avenue to investigate the functions of AMPs and/or other peptide molecules, for a new up-and-coming pharmacological approach to address CF lung disease.
Assuntos
Peptídeos Antimicrobianos/metabolismo , Peptídeos Antimicrobianos/farmacologia , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Pneumopatias/tratamento farmacológico , Infecções por Pseudomonas/tratamento farmacológico , Animais , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Bicarbonatos/metabolismo , Cloretos/metabolismo , Fibrose Cística/genética , Fibrose Cística/microbiologia , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Humanos , Transporte de Íons/efeitos dos fármacos , Pneumopatias/microbiologia , Pneumopatias/patologia , Infecções por Pseudomonas/patologia , Pseudomonas aeruginosa/patogenicidade , Ratos , Ratos Endogâmicos F344RESUMO
Acipimox, a nicotinic acid derivative in clinical use for the treatment of hyperlipidaemia, incorporates a free carboxylic acid and an N-oxide moiety, functionalities known to interact with the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) and inhibit its activity. Herein we report that acipimox acts as a low micromolar CA inhibitor (CAI) against most human (h) isoforms possessing catalytic activity, hCA I - XIV. By using computational techniques (docking and molecular dynamics simulations), we propose that acipimox coordinates through its carboxylate group to the zinc ion from the enzyme active site cavity, whereas the N-oxide group is hydrogen-bonded to the proton shuttle His residue in some isoforms (hCA I) or to active site Thr or Gln residues in other isoforms (hCA II, III, IV, VII, etc). As some CA isoforms are involved in lipogenesis, these data may be useful for the design of more effective CAIs with antiobesity activity.
Assuntos
Inibidores da Anidrase Carbônica/farmacologia , Anidrases Carbônicas/metabolismo , Pirazinas/farmacologia , Inibidores da Anidrase Carbônica/síntese química , Inibidores da Anidrase Carbônica/química , Relação Dose-Resposta a Droga , Humanos , Isoenzimas/antagonistas & inibidores , Isoenzimas/metabolismo , Modelos Moleculares , Estrutura Molecular , Pirazinas/síntese química , Pirazinas/química , Relação Estrutura-AtividadeRESUMO
Human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms IX and XII are overexpressed in solid hypoxic tumors, and they are considered as prognostic tools and therapeutic targets for cancer. Based on a molecular simplification of the well-known coumarin scaffold, we developed a new series of derivatives of the pyran-2-one core. The new compounds are endowed with potent and selective inhibitory activity against the tumor-related hCA isoforms IX and XII, in the low nanomolar range, whereas they are inactive against the two cytosolic off-targets hCA I and II. The compounds exhibiting the best hCA inhibition were further investigated against the breast adenocarcinoma cell line (MCF7) in hypoxic conditions, evaluating their ability to eventually synergize with doxorubicin. The compounds' biocompatibility on healthy cells was also tested and confirmed on Human Gingival Fibroblasts (HGFs). Furthermore, the possible binding mode of all compounds to the active site of the tumor-associated human CA IX was investigated by computational techniques which predicted the binding conformations and the persistency of binding poses within the active site of the enzyme, furnishing relevant data for the design of tight binding inhibitors.
Assuntos
Anidrases Carbônicas , Neoplasias , Antígenos de Neoplasias/metabolismo , Anidrase Carbônica IX/metabolismo , Inibidores da Anidrase Carbônica/química , Anidrases Carbônicas/metabolismo , Humanos , Estrutura Molecular , Neoplasias/metabolismo , Pironas/uso terapêutico , Relação Estrutura-AtividadeRESUMO
Gene expression regulation by small interfering RNA (siRNA) holds promise in treating a wide range of diseases through selective gene silencing. However, successful clinical application of nucleic acid-based therapy requires novel delivery options. Herein, to achieve efficient delivery of negatively charged siRNA duplexes, the internal cavity of "humanized" chimeric Archaeal ferritin (HumAfFt) was specifically decorated with novel cationic piperazine-based compounds (PAs). By coupling these rigid-rod-like amines with thiol-reactive reagents, chemoselective conjugation was efficiently afforded on topologically selected cysteine residues properly located inside HumAfFt. The capability of PAs-HumAfFt to host and deliver siRNA molecules through human transferrin receptor (TfR1), overexpressed in many cancer cells, was explored. These systems allowed siRNA delivery into HeLa, HepG2, and MCF-7 cancer cells with improved silencing effect on glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene expression with respect to traditional transfection methodologies and provided a promising TfR1-targeting system for multifunctional siRNA delivery to therapeutic applications.
Assuntos
Portadores de Fármacos/química , Portadores de Fármacos/síntese química , Desenho de Fármacos , Ferritinas/química , Piperazina/química , RNA Interferente Pequeno/química , Linhagem Celular Tumoral , Técnicas de Química Sintética , Humanos , RNA Interferente Pequeno/metabolismoRESUMO
Withanolides constitute a well-known family of plant-based alkaloids characterised by widespread biological properties, including the ability of interfering with Hedgehog (Hh) signalling pathway. Following our interest in natural products and in anticancer compounds, we report here the synthesis of a new class of Hh signalling pathway inhibitors, inspired by withaferin A, the first isolated member of withanolides. The decoration of our scaffolds was rationally supported by in silico studies, while functional evaluation revealed promising candidates, confirming once again the importance of natural products as inspiration source for the discovery of novel bioactive compounds. A stereoselective approach, based on Brown chemistry, allowed the obtainment and the functional evaluation of the enantiopure hit compounds.
Assuntos
Antineoplásicos , Vitanolídeos , Antineoplásicos/farmacologia , Proteínas Hedgehog/farmacologia , Transdução de Sinais , Vitanolídeos/farmacologiaRESUMO
Cassia abbreviata is widely used in Sub-Saharan Africa for treating many diseases, including HIV-1 infection. We have recently described the chemical structures of 28 compounds isolated from an alcoholic crude extract of barks and roots of C. abbreviata, and showed that six bioactive compounds inhibit HIV-1 infection. In the present study, we demonstrate that the six compounds block HIV-1 entry into cells: oleanolic acid, palmitic acid, taxifolin, piceatannol, guibourtinidol-(4αâ8)-epiafzelechin, and a novel compound named as cassiabrevone. We report, for the first time, that guibourtinidol-(4αâ8)-epiafzelechin and cassiabrevone inhibit HIV-1 entry (IC50 of 42.47 µM and 30.96 µM, respectively), as well as that piceatannol interacts with cellular membranes. Piceatannol inhibits HIV-1 infection in a dual-chamber assay mimicking the female genital tract, as well as HSV infection, emphasizing its potential as a microbicide. Structure-activity relationships (SAR) showed that pharmacophoric groups of piceatannol are strictly required to inhibit HIV-1 entry. By a ligand-based in silico study, we speculated that piceatannol and norartocarpetin may have a very similar mechanism of action and efficacy because of the highly comparable pharmacophoric and 3D space, while guibourtinidol-(4αâ8)-epiafzelechin and cassiabrevone may display a different mechanism. We finally show that cassiabrevone plays a major role of the crude extract of CA by blocking the binding activity of HIV-1 gp120 and CD4.
Assuntos
Cassia/química , Infecções por HIV/tratamento farmacológico , Extratos Vegetais/farmacologia , Internalização do Vírus/efeitos dos fármacos , Catequina/farmacologia , Proteína gp120 do Envelope de HIV/genética , Infecções por HIV/genética , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , HIV-1/patogenicidade , Humanos , Ácido Oleanólico/farmacologia , Ácido Palmítico/farmacologia , Extratos Vegetais/química , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Raízes de Plantas/virologia , Quercetina/análogos & derivados , Quercetina/farmacologia , Estilbenos/farmacologiaRESUMO
The nucleotide analog sofosbuvir, licensed for the treatment of hepatitis C, recently revealed activity against the Zika virus (ZIKV) in vitro and in animal models. However, the ZIKV genetic barrier to sofosbuvir has not yet been characterized. In this study, in vitro selection experiments were performed in infected human hepatoma cell lines. Increasing drug pressure significantly delayed viral breakthrough (p = 0.029). A double mutant in the NS5 gene (V360L/V607I) emerged in 3 independent experiments at 40-80 µM sofosbuvir resulting in a 3.9 ± 0.9-fold half- maximal inhibitory concentration (IC50) shift with respect to the wild type (WT) virus. A triple mutant (C269Y/V360L/V607I), detected in one experiment at 80 µM, conferred a 6.8-fold IC50 shift with respect to the WT. Molecular dynamics simulations confirmed that the double mutant V360L/V607I impacts the binding mode of sofosbuvir, supporting its role in sofosbuvir resistance. Due to the distance from the catalytic site and to the lack of reliable structural data, the contribution of C269Y was not investigated in silico. By a combination of sequence analysis, phenotypic susceptibility testing, and molecular modeling, we characterized a double ZIKV NS5 mutant with decreased sofosbuvir susceptibility. These data add important information to the profile of sofosbuvir as a possible lead for anti-ZIKV drug development.
Assuntos
Substituição de Aminoácidos , Antivirais/farmacologia , Mutação Puntual , RNA Polimerase Dependente de RNA/antagonistas & inibidores , Sofosbuvir/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Zika virus/efeitos dos fármacos , Animais , Antivirais/uso terapêutico , Sítios de Ligação , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Chlorocebus aethiops , Humanos , Concentração Inibidora 50 , Neoplasias Hepáticas/patologia , Modelos Moleculares , Simulação de Dinâmica Molecular , Ligação Proteica , Conformação Proteica , RNA Viral/biossíntese , RNA Viral/genética , RNA Polimerase Dependente de RNA/genética , RNA Polimerase Dependente de RNA/metabolismo , Seleção Genética , Sofosbuvir/uso terapêutico , Células Vero , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo , Replicação Viral/efeitos dos fármacos , Zika virus/enzimologia , Zika virus/genéticaRESUMO
Thienoguanosine (thG) is an isomorphic guanosine (G) surrogate that almost perfectly mimics G in nucleic acids. To exploit its full potential and lay the foundation for future applications, 20 DNA duplexes, where the bases facing and neighboring thG were systematically varied, were thoroughly studied using fluorescence spectroscopy, molecular dynamics simulations, and mixed quantum mechanical/molecular mechanics calculations, yielding a comprehensive understanding of its photophysics in DNA. In matched duplexes, thG's hypochromism was larger for flanking G/C residues but its fluorescence quantum yield (QY) and lifetime values were almost independent of the flanking bases. This was attributed to high duplex stability, which maintains a steady orientation and distance between nucleobases, so that a similar charge transfer (CT) mechanism governs the photophysics of thG independently of its flanking nucleobases. thG can therefore replace any G residue in matched duplexes, while always maintaining similar photophysical features. In contrast, the local destabilization induced by a mismatch or an abasic site restores a strong dependence of thG's QY and lifetime values on its environmental context, depending on the CT route efficiency and solvent exposure of thG. Due to this exquisite sensitivity, thG appears ideal for monitoring local structural changes and single nucleotide polymorphism. Moreover, thG's dominant fluorescence lifetime in DNA is unusually long (9-29 ns), facilitating its selective measurement in complex media using a lifetime-based or a time-gated detection scheme. Taken together, our data highlight thG as an outstanding emissive substitute for G with good QY, long fluorescence lifetimes, and exquisite sensitivity to local structural changes.
Assuntos
Sondas de DNA/química , DNA/química , Corantes Fluorescentes/química , Guanosina/análogos & derivados , Guanosina/química , Cinética , Simulação de Dinâmica Molecular , Conformação de Ácido Nucleico , Solventes/química , Espectrometria de Fluorescência , Relação Estrutura-AtividadeRESUMO
BACKGROUND: Colistin is a last-resort treatment option for many MDR Gram-negative bacteria. The covalent addition of l-aminoarabinose to the lipid A moiety of LPS is the main colistin resistance mechanism in the human pathogen Pseudomonas aeruginosa. OBJECTIVES: Identification (by in silico screening of a chemical library) of potential inhibitors of ArnT, which catalyses the last committed step of lipid A aminoarabinosylation, and their validation in vitro as colistin adjuvants. METHODS: The available ArnT crystal structure was used for a docking-based virtual screening of an in-house library of natural products. The resulting putative ArnT inhibitors were tested in growth inhibition assays using a reference colistin-resistant P. aeruginosa strain. The most promising compound was further characterized for its range of activity, specificity and cytotoxicity. Additionally, the effect of the compound on lipid A aminoarabinosylation was verified by MS analyses of lipid A. RESULTS: A putative ArnT inhibitor (BBN149) was discovered by molecular docking and demonstrated to specifically potentiate colistin activity in colistin-resistant P. aeruginosa isolates, without relevant effect on colistin-susceptible strains. BBN149 also showed adjuvant activity against colistin-resistant Klebsiella pneumoniae and low toxicity to bronchial epithelial cells. Lipid A aminoarabinosylation was reduced in BBN149-treated cells, although only partially. CONCLUSIONS: This study demonstrates that in silico screening targeting ArnT can successfully identify inhibitors of colistin resistance and provides a promising lead compound for the development of colistin adjuvants for the treatment of MDR bacterial infections.