Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 433
Filtrar
2.
Arch Microbiol ; 202(5): 1059-1068, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32020245

RESUMO

Acinetobacter baumannii is the major nosocomial pathogen that causes serious infections such as ventilator-associated pneumonia and bacteremia due to its biofilms. Hence, this study investigated the antimicrobial and antibiofilm potentials of cell-free supernatants (CFS) obtained from Clostridium butyricum, as probiotic, against A. baumannii. Our results demonstrated that C. butyricum CFS inhibited A. baumannii cell growth in planktonic culture. Also, C. butyricum CFS not only inhibited the biofilm development and dispersed mature biofilms, but also suppressed the metabolic activity of biofilm cells, showing antibiofilm activity. The biofilm components reduced by C. butyricum CFS were observed via confocal laser scanning microscopy. In addition, C. butyricum CFS exhibited antivirulence effect by inhibiting the motility of A. baumannii. Furthermore, C. butyricum CFS significantly downregulated the expression of efflux pump-related genes including adeA, adeB and adeC in A. baumannii. Our data demonstrate that C. butyricum CFS showed antimicrobial and antibiofilm effects on A. baumannii. These effects are closely associated with suppression of motility and efflux pump-related genes in A. baumannii. The findings suggest that C. butyricum CFS can be used as a new therapeutic alternative against biofilm-associated infection caused by multidrug-resistant A. baumannii.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/crescimento & desenvolvimento , Antibacterianos/farmacologia , Biofilmes/crescimento & desenvolvimento , Clostridium butyricum/metabolismo , Antibiose/fisiologia , Humanos , Locomoção/efeitos dos fármacos , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Probióticos
3.
PLoS Pathog ; 15(12): e1008101, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31877175

RESUMO

Active efflux due to tripartite RND efflux pumps is an important mechanism of clinically relevant antibiotic resistance in Gram-negative bacteria. These pumps are also essential for Gram-negative pathogens to cause infection and form biofilms. They consist of an inner membrane RND transporter; a periplasmic adaptor protein (PAP), and an outer membrane channel. The role of PAPs in assembly, and the identities of specific residues involved in PAP-RND binding, remain poorly understood. Using recent high-resolution structures, four 3D sites involved in PAP-RND binding within each PAP protomer were defined that correspond to nine discrete linear binding sequences or "binding boxes" within the PAP sequence. In the important human pathogen Salmonella enterica, these binding boxes are conserved within phylogenetically-related PAPs, such as AcrA and AcrE, while differing considerably between divergent PAPs such as MdsA and MdtA, despite overall conservation of the PAP structure. By analysing these binding sequences we created a predictive model of PAP-RND interaction, which suggested the determinants that may allow promiscuity between certain PAPs, but discrimination of others. We corroborated these predictions using direct phenotypic data, confirming that only AcrA and AcrE, but not MdtA or MsdA, can function with the major RND pump AcrB. Furthermore, we provide functional validation of the involvement of the binding boxes by disruptive site-directed mutagenesis. These results directly link sequence conservation within identified PAP binding sites with functional data providing mechanistic explanation for assembly of clinically relevant RND-pumps and explain how Salmonella and other pathogens maintain a degree of redundancy in efflux mediated resistance. Overall, our study provides a novel understanding of the molecular determinants driving the RND-PAP recognition by bridging the available structural information with experimental functional validation thus providing the scientific community with a predictive model of pump-contacts that could be exploited in the future for the development of targeted therapeutics and efflux pump inhibitors.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Infecções Bacterianas/tratamento farmacológico , Proteínas de Bactérias/efeitos dos fármacos , Proteínas de Bactérias/metabolismo , Transporte Biológico/efeitos dos fármacos , Proteínas de Transporte/metabolismo , Feminino , Proteínas de Membrana Transportadoras/metabolismo , Camundongos Endogâmicos BALB C , Periplasma/efeitos dos fármacos , Periplasma/metabolismo , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/metabolismo
4.
Eur J Drug Metab Pharmacokinet ; 44(6): 747-759, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31571146

RESUMO

BACKGROUND AND OBJECTIVES: Darolutamide is a novel androgen receptor (AR) antagonist approved for the treatment of nonmetastatic castration-resistant prostate cancer (nmCRPC). Accordingly, the drug-drug interaction (DDI) potential of darolutamide was investigated in both nonclinical and clinical studies. METHODS: In vitro studies were performed to determine the potential for darolutamide to be a substrate, inducer or inhibitor for cytochrome P450 (CYP) isoforms, other metabolizing enzymes and drug transporters. A phase I drug-interaction study in healthy volunteers evaluated the impact of co-administering rifampicin [CYP3A4 and P-glycoprotein (P-gp) inducer] and itraconazole [CYP3A4, P-gp and breast cancer resistance protein (BCRP) inhibitor] on the pharmacokinetics of darolutamide. Two further phase I studies assessed the impact of co-administering oral darolutamide on the pharmacokinetics of midazolam (sensitive CYP3A4 substrate) and dabigatran etexilate (P-gp substrate) and the impact on the pharmacokinetics of co-administered rosuvastatin [a substrate for BCRP, organic anion-transporting polypeptide (OATP)1B1, OATP1B3 and organic anion transporter (OAT)3]. RESULTS: In vitro, darolutamide was predominantly metabolized via oxidative biotransformation catalyzed by CYP3A4 and was identified as a substrate for P-gp and BCRP. The enzymatic activity of nine CYP isoforms was not inhibited or slightly inhibited in vitro with darolutamide, and a rank order and mechanistic static assessment indicated that risk of clinically relevant DDIs via CYP inhibition is very low. In vitro, darolutamide exhibited no relevant induction of CYP1A2 or CYP2B6 activity. Inhibition of BCRP-, P-gp-, OAT3-, MATE1-, MATE2-K-, OATP1B1- and OATP1B3-mediated transport was observed in vitro. Phase I data showed that darolutamide exposure increased 1.75-fold with co-administered itraconazole and decreased by 72% with rifampicin. Co-administration of darolutamide with CYP3A4/P-gp substrates showed no effect or only minor effects. Rosuvastatin exposure increased 5.2-fold with darolutamide because of BCRP and probably also OATPB1/OATPB3 inhibition. CONCLUSIONS: Darolutamide has a low potential for clinically relevant DDIs with drugs that are substrates for CYP or P-gp; increased exposure of BCRP and probably OATP substrates was the main interaction of note.


Assuntos
Sistema Enzimático do Citocromo P-450/efeitos dos fármacos , Interações Medicamentosas , Pirazóis/farmacologia , Pirazóis/farmacocinética , Idoso , Células Cultivadas , Indutores do Citocromo P-450 CYP3A/farmacologia , Inibidores do Citocromo P-450 CYP3A/farmacologia , Dabigatrana/farmacocinética , Indução Enzimática/efeitos dos fármacos , Feminino , Humanos , Itraconazol/farmacologia , Masculino , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Microssomos Hepáticos/efeitos dos fármacos , Midazolam/farmacocinética , Pessoa de Meia-Idade , Pirazóis/sangue , Pirazóis/urina , Rifampina/farmacologia , Rosuvastatina Cálcica/farmacocinética
5.
An Acad Bras Cienc ; 91(3): e20180654, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31365653

RESUMO

Candida albicans is the most frequent fungal species that causes infections in humans. Fluconazole is the main antifungal used to treat Candida infections, and its prolonged and indiscriminate use for the last decades are the most established causes which originated resistant strains. Fungal drug resistance is associated to alterations in ERG11 gene and overexpression of multidrug resistance (MDR) transporters belonging to two families: ATP-binding cassette (ABC) and Major Facilitator Superfamily (MFS). To evaluate the role of MFS transporters in azoles resistance of C. albicans clinical strains, this study aimed to analyze four Candida albicans clinical isolates from the University Hospital in Juiz de Fora (Minas Gerais/Brazil), selected in our previous study as they were unaffected by FK506, an ABC pumps inhibitor. In a primary investigation on MFS proteins overexpression, the extrusion of fluorescent substrates (rhodamine 6G and nile red) was analyzed by fluorescence microscopy and flow cytometry. Results suggest participation of MFS transporters in azole resistance of C. albicans isolates and indicate the existence of secondary resistance mechanisms. Therefore, this study contributes to the information about Candida albicans infections in Brazil and reinforces the importance of epidemiological studies focusing on an improved understanding of the disease and further resistance reversion.


Assuntos
Antifúngicos/farmacologia , Azóis/farmacologia , Candida albicans/efeitos dos fármacos , Proteínas de Membrana Transportadoras/metabolismo , Azóis/classificação , Transporte Biológico/efeitos dos fármacos , Citometria de Fluxo , Humanos , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Microscopia de Fluorescência , Centros de Atenção Terciária
6.
Artigo em Inglês | MEDLINE | ID: mdl-31281800

RESUMO

The frequent emergence of azole-resistant strains has increasingly led azoles to fail in treating candidiasis. Combination with other drugs is a good option to effectively reduce or retard its incidence of resistance. Natural products are a promising synergist source to assist azoles in treating resistant candidiasis. Eucalyptal D (ED), a formyl-phloroglucinol meroterpenoid, is one of the natural synergists, which could significantly enhance the anticandidal activity of fluconazole (FLC) in treating FLC resistant C. albicans. The checkerboard microdilution assay showed their synergistic effect. The agar disk diffusion test illustrated the key role of ED in synergy. The rhodamine 6G (R6G) efflux assay reflected ED could reduce drug efflux, but quantitative reverse transcription PCR analysis revealed the upregulation of CDR1 and CDR2 genes in ED treating group. Efflux pump-deficient strains were hyper-susceptible to ED, thus ED was speculated to be the substrate of efflux pump Cdr1p and Cdr2p to competitively inhibit the excretion of FLC or R6G, which mainly contributed to its synergistic effect.


Assuntos
Antifúngicos/farmacologia , Transporte Biológico/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Farmacorresistência Fúngica/efeitos dos fármacos , Fluconazol/farmacologia , Triterpenos/farmacologia , Transportadores de Cassetes de Ligação de ATP/efeitos dos fármacos , Azóis/farmacologia , Benzaldeídos , Candida albicans/genética , Candidíase/tratamento farmacológico , Sinergismo Farmacológico , Proteínas Fúngicas/genética , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Proteínas de Membrana Transportadoras/genética , Testes de Sensibilidade Microbiana , Floroglucinol/análogos & derivados , Triterpenos/química
7.
J Microbiol Immunol Infect ; 52(4): 638-647, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31239204

RESUMO

BACKGROUND: The emergence of multiple-antibiotic-resistant (MAR) Salmonella has been a serious threat worldwide. Salmonella can invade into host cells and evade the attacks of host humoral defenses and antibiotics. Thus, a new antibacterial agent capable of inhibiting intracellular Salmonella is highly needed. METHODS: The anti-intracellular activity and cytotoxicity of drugs on intracellular bacteria and macrophages were assayed using intracellular CFU assay and MTT cell viability assay, respectively. The uptake of gentamicin into macrophage and the effect of autophagy inhibitor on loxapine's anti-intracellular Salmonella activity were assessed by using image-based high-content system. The expression of bacterial genes was measured by real-time PCR. The efflux pump activity of bacteria was measured by Hoechst accumulation assays. RESULTS: With our efforts, an antipsychotic drug, loxapine, was identified to exhibit high potency in suppressing intracellular MAR S. Typhimurium, Staphylococcus aureus, Shigella flexneri or Yersinia enterocolitica. Subsequent investigations indicated that loxapine's anti-intracellular bacteria activity was not associated with increased penetration of gentamicin into bacteria and macrophages. Loxapine didn't inhibit bacterial growth in broth at concentration up to 500 µM and has no effect on Salmonella's type III secretion system genes' expression. Blockage of autophagy also didn't reverse loxapine's anti-intracellular activity. Lastly, loxapine suppressed bacterial efflux pump activity in all bacteria tested. CONCLUSION: Altogether, our data suggested that loxapine might suppress intracellular bacteria through inhibiting of bacterial efflux pumps. In light of its unique activity, loxapine represents a promising lead compound with translational potential for the development of a new antibacterial agent against intracellular bacteria.


Assuntos
Antibacterianos/farmacologia , Antipsicóticos/farmacologia , Loxapina/farmacologia , Macrófagos/microbiologia , Salmonella typhimurium/efeitos dos fármacos , Animais , Autofagia/efeitos dos fármacos , Proteínas de Bactérias/genética , Sobrevivência Celular/efeitos dos fármacos , Contagem de Colônia Microbiana , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Fluoroquinolonas/farmacologia , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Gentamicinas/farmacologia , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Proteínas de Membrana Transportadoras/genética , Camundongos , Testes de Sensibilidade Microbiana , Fenotiazinas/farmacologia , Células RAW 264.7 , Salmonella typhimurium/genética , Salmonella typhimurium/crescimento & desenvolvimento , Sorogrupo , Shigella flexneri/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Sistemas de Secreção Tipo III/efeitos dos fármacos , Sistemas de Secreção Tipo III/genética , Yersinia enterocolitica/efeitos dos fármacos
8.
Indian J Med Res ; 149(2): 129-145, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-31219077

RESUMO

With the advent of antibiotics, bacterial infections were supposed to be a thing of past. However, this instead led to the selection and evolution of bacteria with mechanisms to counter the action of antibiotics. Antibiotic efflux is one of the major mechanisms, whereby bacteria pump out the antibiotics from their cellular interior to the external environment using special transporter proteins called efflux pumps. Inhibiting these pumps seems to be an attractive strategy at a time when novel antibiotic supplies are dwindling. Molecules capable of inhibiting these pumps, known as efflux pump inhibitors (EPIs), have been viewed as potential therapeutic agents that can rejuvenate the activity of antibiotics that are no longer effective against bacterial pathogens. EPIs follow some general mechanisms of efflux inhibition and are derived from various natural as well as synthetic sources. This review focuses on EPIs and identifies the challenges that have kept these futuristic therapeutics away from the commercial realm so far.


Assuntos
Anti-Infecciosos/uso terapêutico , Bactérias/efeitos dos fármacos , Infecções Bacterianas/tratamento farmacológico , Farmacorresistência Bacteriana Múltipla , Antibacterianos/efeitos adversos , Bactérias/patogenicidade , Infecções Bacterianas/epidemiologia , Infecções Bacterianas/microbiologia , Humanos , Índia/epidemiologia , Proteínas de Membrana Transportadoras/efeitos dos fármacos
9.
Eur J Med Chem ; 178: 30-38, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31173969

RESUMO

Several studies that have identified agents that potentiate the antimicrobial activity of antibiotics, but there are limited insights into their structure-activity relationships (SAR). The SAR associated with select N-alkylaryl amide derivatives of ornithine was performed to establish those structural features that were associated with potentiation of the antimicrobial activity of clarithromycin against E. coli ATCC 25922. The data indicate that the N-propyl derivative was slightly more active in reducing the effective MIC of clarithromycin against E. coli ATCC 25922. In addition, the S-enantiomer of compound 9 was somewhat more potent than the R-enantiomer in potentiating clarithromycin activity. No significant enhancement in potentiation activity was observed with the conversion of these secondary amides to their N-methyl tertiary amides. Formation of the N-methyl or N,N-dimethyl derivatives of the primary amine of 9 was associated with the loss of potentiation activity. Conversion of this primary amine to a guanidine was also not associated with an increase in potentiation activity. Among the isomeric diamino pentamides, 15 potentiated the antibacterial activity of clarithromycin to the greatest extent. In addition to these amide derivatives, the desoxy derivatives 16 and 18 were the more potent potentiators within this triamine series. The relative location of the primary amines, as indicated by the relative differences in the potentiation observed with 16 compared to 14, appears to be a critical factor in determining potentiation activity. Cell-based membrane permeabilization and efflux inhibition studies in E. coli ATCC 25922 suggest that the potentiation of clarithromycin activity by 16 reflects its ability to inhibit efflux pump activity and to a lesser extent its actions as a permeabilizer of the outer leaflet of the outer cell membrane.


Assuntos
Amidas/farmacologia , Antibacterianos/farmacologia , Claritromicina/farmacologia , Escherichia coli/efeitos dos fármacos , Ornitina/farmacologia , Amidas/síntese química , Amidas/química , Permeabilidade da Membrana Celular/efeitos dos fármacos , Sinergismo Farmacológico , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Ornitina/análogos & derivados , Ornitina/síntese química , Relação Estrutura-Atividade
10.
Methodist Debakey Cardiovasc J ; 15(1): 70-76, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31049152

RESUMO

Besides the well-known hepatobiliary pathway of cholesterol excretion into the feces, transintestinal cholesterol excretion (TICE) is a second major pathway through which cholesterol is disposed from the body. In the process of TICE, cholesterol is taken up from lipoprotein particles at the basolateral side of the enterocyte and translocates towards the apical side of the enterocyte. At the apical side, the ATP-binding cassette transporters G5 and G8 form a heterodimer that transports cholesterol into the intestinal lumen. A substantial amount of the secreted cholesterol is likely reabsorbed by the cholesterol influx transporter Niemann-Pick C1-Like 1 (NPC1L1) since recent data indicate that inhibition of NPC1L1 increases the efficacy of TICE for disposal of cholesterol via the feces. The pathways and proteins involved in intracellular cholesterol trafficking in the enterocyte have not yet been identified. Therefore, in addition to discussing known mediators of TICE, this review will also examine potential candidates involved in cholesterol translocation in the enterocyte. Both the cholesterol reuptake and efflux pathways can be influenced by pharmaceutical means; thus, the TICE pathway is a very attractive target to increase cholesterol excretion from the body and prevent or mitigate atherosclerotic cardiovascular disease.


Assuntos
Anticolesterolemiantes/uso terapêutico , Doenças Cardiovasculares/prevenção & controle , Colesterol/sangue , Dislipidemias/tratamento farmacológico , Enterócitos/efeitos dos fármacos , Eliminação Intestinal/efeitos dos fármacos , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Animais , Anticolesterolemiantes/efeitos adversos , Biomarcadores/sangue , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/epidemiologia , Regulação para Baixo , Dislipidemias/sangue , Dislipidemias/diagnóstico , Dislipidemias/epidemiologia , Enterócitos/metabolismo , Fezes/química , Humanos , Proteínas de Membrana Transportadoras/metabolismo
11.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1864(8): 1124-1133, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31054325

RESUMO

Hypercholesterolemia is a preventable risk factor for atherosclerosis and cardiovascular disease. However, the mechanisms of diosgenin (DG) that promote cholesterol homeostasis and alleviate hypercholesterolemia remain elusive. To investigate the effects and molecular mechanisms of the promotion of cholesterol metabolism by DG, a rat model of hypercholesterolemia was induced by providing a high-fat diet for 4 weeks. After 4 weeks, the rats were intragastrically administered high-dose DG (0.3 g/kg/d), low-dose DG (0.15 g/kg/d) or simvastatin (4 mg/kg/d) once a day for 8 weeks. The serum and hepatic cholesterol were tested, the mRNA and protein expression levels of Niemann-Pick C1-Like 1 (NPC1L1), liver X receptor-α (LXR-α) and the ATP-binding cassette G5/G8 (ABCG5/G8) transporters were measured. The results indicate that DG could reduce body weight, decrease the serum total cholesterol, triglyceride, low-density lipoprotein cholesterol, liver total cholesterol and free cholesterol levels compared to those in the controls. Simultaneously, liver tissue pathological morphology analyses revealed that DG could attenuate hepatic steatosis compared to that in the high-fat diet group. Further investigation demonstrated that DG significantly decreased the expression of NPC1L1 and LXR-α in the intestine and markedly increased the expression of ABCG5/G8 in the liver and intestine. Compared to the high-fat diet group, the rats in the DG-treated groups ameliorated hypercholesterolemia in a dose- and time-dependent manner. These data suggest that DG may not only inhibit intestinal cholesterol absorption by downregulating NPC1L1 but also enhance cholesterol excretion by increasing the expression of ABCG5/G8. DG could be a new candidate for the prevention of hypercholesterolemia.


Assuntos
Membro 5 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/agonistas , Membro 8 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/agonistas , Colesterol/metabolismo , Diosgenina/uso terapêutico , Hipercolesterolemia/tratamento farmacológico , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Animais , Anticolesterolemiantes , Colesterol/sangue , Diosgenina/farmacologia , Hipercolesterolemia/metabolismo , Hipercolesterolemia/prevenção & controle , Mucosa Intestinal/metabolismo , Intestinos , Fígado/metabolismo , Ratos
12.
Mol Biol Rep ; 46(2): 2395-2404, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30778922

RESUMO

Curcumin as a flavonoid from the rhizome of Curcuma longa has antibacterial, antiviral and antifungal activity. Multidrug resistance in pathogenic bacteria is continuously increasing in hospitals. The aim of this study was to investigate the effect of curcumin encapsulated in micellar/polymersome nanoparticles as an efflux pump inhibitor (EPI) on the expression of mexX and oprM genes in curcumin-treated and -untreated isolates of Pseudomonas aeruginosa. Clinical isolates of Pseudomonas aeruginosa were treated with ciprofloxacin (sub-MICs) alone and/or in combination with curcumin-encapsulated in micellar/polymersome nanoparticles. The expression of mexX and oprM genes was quantitatively evaluated by qRT-PCR in curcumin-treated and -untreated bacteria after 24 h. Curcumin-encapsulated in nanoparticles (400 µg/mL) induced cell death up to 50% in ciprofloxacin-treated (1/2MIC) resistant isolates during 24 h, while the bacteria treated with ciprofloxacin (without curcumin) were not inhibited. Also, curcumin in different concentrations increased effect of ciprofloxacin (sub-MICs). Downregulation of mexX and oprM genes was observed in cells treated with curcumin and ciprofloxacin compared to cells treated with ciprofloxacin alone. It seems that curcumin can be used as complementary drug in ciprofloxacin-resistant isolates through downregulating genes involved in efflux pumps and trapping ciprofloxacin on bacterial cells and increasing the effects of drug.


Assuntos
Curcumina/farmacologia , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Bactérias/efeitos dos fármacos , Ciprofloxacino/farmacologia , Curcumina/administração & dosagem , Curcumina/metabolismo , Regulação para Baixo , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Humanos , Proteínas de Membrana Transportadoras/genética , Testes de Sensibilidade Microbiana , Nanopartículas/uso terapêutico
13.
J Photochem Photobiol B ; 192: 141-146, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30735955

RESUMO

Multidrug resistance (MDR) in bacteria is a major concern these days. One of the reasons is the mutation in efflux pump that prevents the retention of antibiotics and drugs in the bacterial cell. The current work is a step to overcome MDR in bacteria via inhibition of efflux pump and further photoinhibition by thiolated chitosan coated cobalt doped zinc oxide nanoparticles (Co-ZnO) in visible light. Co-ZnO were synthesized in a size range of 40-60 nm. Antibacterial activity of the Co-ZnO against methicillin resistant Staphylococcus aureus (MRSA) was found 100% at a concentration of 10 µg/ml upon activation in sunlight for 15 min. Interestingly, it was found that cobalt as a dopant was able to increase the photodynamic and photothermal activity of Co-ZnO, as in dark conditions, there was only 3-5% of inhibition at 10 µg/ml of nanoparticle concentration. Upon excitation in light, these nanoparticles were able to generate reactive oxygen species (ROS) with a quantum yield of 0.23 ±â€¯0.034. The nanoparticles were also generating heat, Because of the magnetic nature, thus helping in more killing. Thiolated chitosan further helped in blocking the efflux pump of MRSA. The current nanoparticles were also found biocompatible on human red blood cells (LD50 = 214 µg/ml). These data suggest that the MRSA killing ability was facilitated through efflux inhibition and oxidative stress upon excitation in visible light hence, were in accordance with previous findings.


Assuntos
Cobalto/química , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Fotólise , Óxido de Zinco/farmacologia , Proteínas de Bactérias , Cobalto/uso terapêutico , Eritrócitos , Humanos , Luz , Nanopartículas/uso terapêutico , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Óxido de Zinco/uso terapêutico
14.
Drug Metab Dispos ; 47(4): 412-418, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30674615

RESUMO

In the liver, several approaches are used to investigate and predict the complex issue of drug-induced transporter inhibition. These approaches include in vitro assays and pharmacokinetic models that predict how inhibitors modify the systemic and liver concentrations of the victim drugs. Imaging is another approach that shows how inhibitors might alter liver concentrations stronger than systemic concentrations. In perfused rat livers associated with a gamma counter that measures liver concentrations continuously, we previously showed how fluxes across transporters generate the hepatocyte concentrations of two clinical imaging compounds, one with a low extraction ratio [gadobenate dimeglumine (BOPTA)] and one with a high extraction ratio [mebrofenin (MEB)]. BOPTA and MEB are transported by rat organic anion transporting polypeptide and multiple resistance-associated protein 2, which are both inhibited by rifampicin. The aim of the study is to measure how rifampicin modifies the hepatocyte concentrations and membrane clearances of BOPTA and MEB and to determine whether these compounds might be used to investigate transporter-mediated drug-drug interactions in clinical studies. We show that rifampicin coperfusion greatly decreases BOPTA hepatocyte concentrations, but increases those of MEB. Rifampicin strongly decreases BOPTA hepatic clearance. In contrast, rifampicin decreases moderately MEB hepatic clearance and blocks the biliary intrinsic clearance, increasing MEB hepatocyte concentrations. In conclusion, low concentrations prevent the quantification of BOPTA biliary intrinsic clearance, while MEB is a promising imaging probe substrate to evidence transporter-mediated drug-drug interactions when inhibitors act on influx and efflux transporters.


Assuntos
Transporte Biológico/fisiologia , Hepatócitos/metabolismo , Fígado/metabolismo , Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Sistema Biliar/efeitos dos fármacos , Sistema Biliar/metabolismo , Transporte Biológico/efeitos dos fármacos , Meios de Contraste/metabolismo , Interações Medicamentosas/fisiologia , Hepatócitos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Masculino , Meglumina/análogos & derivados , Meglumina/metabolismo , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Proteínas de Membrana Transportadoras/metabolismo , Transportadores de Ânions Orgânicos/metabolismo , Compostos Organometálicos/metabolismo , Ratos , Ratos Sprague-Dawley , Rifampina/farmacologia
15.
Future Microbiol ; 14: 185-194, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30648892

RESUMO

AIM: To evaluate modulatory effect of verapamil (VP) in rifampicin (RIF) activity and its effect in efflux pumps (EPs) transcript levels in Mycobacterium tuberculosis. MATERIALS & METHODS: RIF and VP minimal inhibitory concentration, combinatory effect and detection of mutations were determined in 16 isolates. EPs transcript levels were determined in four isolates by real-time PCR after exposure to drugs. RESULTS: VP showed good combinatory effect among RIF-resistant isolates. This effect was also observed in the relative transcript levels of EPs, mainly after 72 h of exposure, depending on the EP gene, genotype and the resistance profile of the isolate. CONCLUSION: Additional regulatory mechanisms in the EP activities, as well as, interactions with other drug-specific resistance mechanisms need further investigation in M. tuberculosis.


Assuntos
Antituberculosos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Mycobacterium tuberculosis/efeitos dos fármacos , Rifampina/farmacologia , Verapamil/farmacologia , Proteínas de Bactérias/efeitos dos fármacos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Brasil , Catalase/genética , RNA Polimerases Dirigidas por DNA/genética , Sinergismo Farmacológico , Quimioterapia Combinada , Regulação Bacteriana da Expressão Gênica , Genótipo , Humanos , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Testes de Sensibilidade Microbiana , Mutação , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/metabolismo , Oxirredutases/genética , Fatores de Tempo , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia
16.
Cardiovasc Drugs Ther ; 33(1): 35-44, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30671747

RESUMO

PURPOSE: Oxycholesterols (OCs) are produced from cholesterol by oxidation of the steroidal backbone and side-chain. OCs are present in blood and evidence suggests their involvement in disease development and progression. However, limited information is available regarding the absorption mechanisms and relative absorption rates of dietary OCs. Although ezetimibe is known to inhibit intestinal cholesterol absorption via Niemann-Pick C1-Like 1 (NPC1L1), whether it also inhibits dietary OC absorption is unclear. METHODS: We investigated the effects of ezetimibe on OC absorption in rats fed an OC-rich diet containing 10 different OCs. We collected lymphatic fluid using permanent cannulation of the thoracic duct and quantified OC levels. RESULTS: Ezetimibe treatment significantly reduced the apparent absorption of 5ß,6ß-epoxycholesterol (5,6ß-epoxy) and its levels in the proximal intestinal mucosa in OC-fed rats. Using in silico analyses, the binding energy of NPC1L1 N-terminal domain (NPC1L1-NTD) and 5,6ß-epoxy was found to be similar to that of NPC1L1-NTD and cholesterol, suggesting that polar uncharged amino acids located in the steroidal part of 5,6ß-epoxy were involved. CONCLUSION: Our results indicate that ezetimibe-mediated inhibition of dietary OC absorption varies depending on the specific OC, and only the absorption of 5,6ß-epoxy is significantly reduced.


Assuntos
Anticolesterolemiantes/farmacologia , Colesterol/análogos & derivados , Dieta , Ezetimiba/farmacologia , Absorção Intestinal/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Administração Oral , Ração Animal , Animais , Colesterol/administração & dosagem , Colesterol/metabolismo , Mucosa Intestinal/metabolismo , Masculino , Proteínas de Membrana Transportadoras/metabolismo , Simulação de Acoplamento Molecular , Ratos Sprague-Dawley , Ducto Torácico/efeitos dos fármacos , Ducto Torácico/metabolismo
17.
Arch Microbiol ; 201(1): 123-134, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30283989

RESUMO

Myo-inositol is a precursor of several membrane phospholipids and sphingolipids and plays a key role in gene regulation in Saccharomyces cerevisiae (S. cerevisiae). Here, we tested whether H2O2 was affecting the levels of the inositol transporters and thus inositol uptake. In S. cerevisiae cells adapted to H2O2 Itr1-GFPp accumulated in the plasma membrane until 20 min, concomitantly with an inhibition of its internalization. Exposure to H2O2 did not alter Itr2-GFPp cellular levels and induced only an 8% decrease at 10 min in the plasma membrane. Therefore, decreased inositol intracellular levels are not caused by decreased levels of inositol transporters in the plasma membrane. However, results show that H2O2 adaptation affects Itr1p turnover and, consequently, H2O2-adapted yeast cells display an inositol transporter phenotype comparable to cells grown in the absence of inositol in growth medium, i.e. accumulation in the plasma membrane and decreased degradation.


Assuntos
Peróxido de Hidrogênio/farmacologia , Inositol/metabolismo , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Proteínas de Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Adaptação Fisiológica , Transporte Biológico/efeitos dos fármacos , Transporte Biológico/genética , Proteínas de Membrana Transportadoras/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética
18.
Expert Opin Drug Metab Toxicol ; 15(2): 167-177, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30582378

RESUMO

INTRODUCTION: Glycyrrhizae Radix et Rhizoma (Gancao in Chinese) is the most frequently used traditional Chinese medicine (TCM) owing to its various pharmacological effects and, more importantly, the synergistic effects that enhance the efficacy and reduce the toxicity of other TCMs. Areas covered: We reviewed publications, predominantly between 1990 and 2018, that examined pharmacokinetic interactions between Gancao and other TCMs, or the bioactive constituents of these TCMs. This review focuses on the underlying mechanisms and the components responsible for the pharmacokinetic modulation by Gancao. Expert opinion: In general, the pharmacokinetic effects of Gancao are a result of its constituents such as macromolecules, like proteins, and small molecules, such as saponins and flavonoids. The mechanisms are related to formation of complexes and the influence of these on drug solubility, permeability, distribution, and metabolism. The detoxification effect of a single dose of Gancao is mainly mediated by the suppression of the intestinal absorption of toxic constituents of the co-administered TCMs and is attributable to constituents that form complexes with the toxic compounds and cause them to sediment. In contrast, the detoxification effects of repeated doses of Gancao are mediated mainly via the induction of drug metabolizing enzymes and efflux transporters.


Assuntos
Medicamentos de Ervas Chinesas/administração & dosagem , Glycyrrhiza/química , Extratos Vegetais/administração & dosagem , Animais , Interações Medicamentosas , Sinergismo Farmacológico , Medicamentos de Ervas Chinesas/efeitos adversos , Medicamentos de Ervas Chinesas/farmacologia , Enzimas/efeitos dos fármacos , Enzimas/metabolismo , Humanos , Absorção Intestinal , Medicina Tradicional Chinesa/efeitos adversos , Medicina Tradicional Chinesa/métodos , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Proteínas de Membrana Transportadoras/metabolismo , Extratos Vegetais/efeitos adversos , Extratos Vegetais/farmacologia
19.
Drug Des Devel Ther ; 12: 4129-4138, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30584277

RESUMO

Introduction: Six years after the US Food and Drug Administration approval of the broad-spectrum antibiotic ofloxacin (OFLX), the chiral switching of this racemic mixture resulted in a drug composed of the L-optical isomer levofloxacin (LVFX). Since both fluoroquinolones (FQs) were introduced to the pharmaceutical market, they have been widely prescribed by physicians, with careful administration during pregnancy and breastfeeding. Therefore, the role of the influx and efflux placental transporters in the concentrations of these drugs that permeate through human placental barrier model was investigated in this study. Methods: The contribution of major carriers on the transplacental flux of OFLX and LVFX uptake into choriocarcinoma BeWo cells was evaluated in the presence vs absence of well-known inhibitors. Results: Our results reveal that neither the influx transporters such as organic cation transporters, organic anion transporters, and monocarboxylate transporters nor the efflux transporters such as P-glycoprotein or breast cancer resistance protein significantly affected the transport of OFLX. In contrast, multiple transporters revealed pronounced involvement in the transfer of the levorotatory enantiomer in and out of the in vitro placental barrier. These data suggest a non-carrier-mediated mechanism of transport of the racemic mixture, while LVFX is subjected to major influx and efflux passage through the placental brush border membranes. Conclusion: This study provides underlying insights to elucidate the governing factors that influence the flux of these FQs through organ barriers, in view of the controversial safety profile of these drugs in pregnant population.


Assuntos
Antibacterianos/metabolismo , Vilosidades Coriônicas/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Ofloxacino/metabolismo , Trofoblastos/metabolismo , Antibacterianos/química , Transporte Biológico , Linhagem Celular Tumoral , Vilosidades Coriônicas/efeitos dos fármacos , Humanos , Cinética , Moduladores de Transporte de Membrana/farmacologia , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Ofloxacino/química , Permeabilidade , Estereoisomerismo , Trofoblastos/efeitos dos fármacos
20.
Exp Hematol ; 68: 30-37.e1, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30395909

RESUMO

Proper control of mitochondrial function is a key factor in the maintenance of hematopoietic stem cells (HSCs). Mitochondrial content is commonly measured by staining with fluorescent cationic dyes. However, dye staining can be affected, not only by xenobiotic efflux pumps, but also by dye intake, which is dependent on the negative charge of mitochondria. Therefore, mitochondrial membrane potential (ΔΨmt) must be considered in these measurements because a high ΔΨmt due to respiratory chain activity can enhance dye intake, leading to the overestimation of mitochondrial volume. Here, we show that HSCs exhibit the highest ΔΨmt of the hematopoietic lineages and, as a result, ΔΨmt-independent methods most accurately assess the relatively low mitochondrial volumes and DNA amounts of HSC mitochondria. Multipotent progenitor stage or active HSCs display expanded mitochondrial volumes, which decline again with further maturation. Further characterization of the controlled remodeling of the mitochondrial landscape at each hematopoietic stage will contribute to a deeper understanding of the mitochondrial role in HSC homeostasis.


Assuntos
Hematopoese , Células-Tronco Hematopoéticas/citologia , Potencial da Membrana Mitocondrial , Tamanho Mitocondrial , Animais , Animais Congênicos , Transporte Biológico Ativo/efeitos dos fármacos , Linhagem da Célula , Células Cultivadas , Feminino , Fibroblastos , Citometria de Fluxo/métodos , Corantes Fluorescentes/análise , Corantes Fluorescentes/metabolismo , Genes Reporter , Proteínas de Fluorescência Verde/análise , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/fisiologia , Masculino , Proteínas de Membrana Transportadoras/efeitos dos fármacos , Proteínas de Membrana Transportadoras/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microscopia Confocal , Quimera por Radiação , Verapamil/farmacologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA