Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
ChemMedChem ; 11(4): 367-73, 2016 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-26812660

RESUMO

Uropathogenic E. coli (UPEC) employ the mannose-binding adhesin FimH to colonize the bladder epithelium during urinary tract infection (UTI). Previously reported FimH antagonists exhibit good potency and efficacy, but low bioavailability and a short half-life in vivo. In a rational design strategy, we obtained an X-ray structure of lead mannosides and then designed mannosides with improved drug-like properties. We show that cyclizing the carboxamide onto the biphenyl B-ring aglycone of biphenyl mannosides into a fused heterocyclic ring, generates new biaryl mannosides such as isoquinolone 22 (2-methyl-4-(1-oxo-1,2-dihydroisoquinolin-7-yl)phenyl α-d-mannopyranoside) with enhanced potency and in vivo efficacy resulting from increased oral bioavailability. N-Substitution of the isoquinolone aglycone with various functionalities produced a new potent subseries of FimH antagonists. All analogues of the subseries have higher FimH binding affinity than unsubstituted lead 22, as determined by thermal shift differential scanning fluorimetry assay. Mannosides with pyridyl substitution on the isoquinolone group inhibit bacteria-mediated hemagglutination and prevent biofilm formation by UPEC with single-digit nanomolar potency, which is unprecedented for any FimH antagonists or any other antivirulence compounds reported to date.


Assuntos
Adesinas de Escherichia coli/metabolismo , Antibacterianos/farmacologia , Infecções por Escherichia coli/tratamento farmacológico , Proteínas de Fímbrias/metabolismo , Manosídeos/farmacologia , Infecções Urinárias/tratamento farmacológico , Escherichia coli Uropatogênica/efeitos dos fármacos , Antibacterianos/química , Doença Crônica , Infecções por Escherichia coli/microbiologia , Humanos , Isoquinolinas/química , Isoquinolinas/farmacologia , Manosídeos/química , Simulação de Acoplamento Molecular , Bexiga Urinária/microbiologia , Infecções Urinárias/microbiologia , Escherichia coli Uropatogênica/metabolismo
2.
Infect Immun ; 80(8): 2826-34, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22665375

RESUMO

Urinary tract infections (UTI), primarily caused by uropathogenic Escherichia coli (UPEC), are one of the leading bacterial infections due to their high frequency and rate of recurrence. Both type 1 pilus adhesive organelles (fim) and the QseC sensor kinase have been implicated in UPEC virulence during UTI and have been individually reported to be promising drug targets. Deletion of qseC leads to pleiotropic effects due to unregulated activation of the cognate response regulator QseB, influencing conserved metabolic processes and diminishing expression of virulence genes, including type 1 pili. Here, we discern the type 1 pilus-dependent and -independent effects that contribute to the virulence attenuation of a UPEC qseC deletion mutant in a murine model of experimental UTI. We show that although a ΔqseC mutant restored for type 1 pilus expression regains the ability to colonize the host and initiate acute infection up to 16 h postinfection, it is rapidly outcompeted during acute infection when coinoculated with a wild-type strain. As a result, this strain has a diminished capacity to establish chronic infection. A prophylactic oral dose of a FimH small-molecular-weight antagonist (ZFH-02056) further reduced the ability of the qseC mutant to establish chronic infection. Thus, loss of QseC significantly enhances the efficacy of ZFH-02056. Collectively, our work indicates that type 1 pili and QseC become critical in different infection stages, and that dual targeting of these factors has an additive effect on ablating UPEC virulence.


Assuntos
Proteínas de Escherichia coli/metabolismo , Fímbrias Bacterianas/metabolismo , Infecções Urinárias/microbiologia , Escherichia coli Uropatogênica/metabolismo , Animais , Proteínas de Escherichia coli/genética , Feminino , Fímbrias Bacterianas/genética , Regulação Bacteriana da Expressão Gênica/fisiologia , Camundongos , Camundongos Endogâmicos C3H , Mutação , Bexiga Urinária/microbiologia , Escherichia coli Uropatogênica/genética , Escherichia coli Uropatogênica/patogenicidade , Virulência
3.
Antimicrob Agents Chemother ; 56(9): 4738-45, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22733070

RESUMO

Catheter-associated urinary tract infections (CAUTIs) constitute the majority of nosocomial urinary tract infections (UTIs) and pose significant clinical challenges. These infections are polymicrobial in nature and are often associated with multidrug-resistant pathogens, including uropathogenic Escherichia coli (UPEC). Urinary catheterization elicits major histological and immunological alterations in the bladder that can favor microbial colonization and dissemination in the urinary tract. We report that these biological perturbations impact UPEC pathogenesis and that bacterial reservoirs established during a previous UPEC infection, in which bacteriuria had resolved, can serve as a nidus for subsequent urinary catheter colonization. Mannosides, small molecule inhibitors of the type 1 pilus adhesin, FimH, provided significant protection against UPEC CAUTI by preventing bacterial invasion and shifting the UPEC niche primarily to the extracellular milieu and on the foreign body. By doing so, mannosides potentiated the action of trimethoprim-sulfamethoxazole in the prevention and treatment of CAUTI. In this study, we provide novel insights into UPEC pathogenesis in the context of urinary catheterization, and demonstrate the efficacy of novel therapies that target critical mechanisms for this infection. Thus, we establish a proof-of-principle for the development of mannosides to prevent and eventually treat these infections in the face of rising antibiotic-resistant uropathogens.


Assuntos
Infecções Relacionadas a Cateter/tratamento farmacológico , Infecção Hospitalar/tratamento farmacológico , Infecções por Escherichia coli/tratamento farmacológico , Manosídeos/farmacologia , Combinação Trimetoprima e Sulfametoxazol/farmacologia , Infecções Urinárias/tratamento farmacológico , Escherichia coli Uropatogênica/efeitos dos fármacos , Adesinas de Escherichia coli/genética , Animais , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Infecções Relacionadas a Cateter/microbiologia , Infecção Hospitalar/microbiologia , Quimioterapia Combinada , Infecções por Escherichia coli/microbiologia , Feminino , Proteínas de Fímbrias/deficiência , Proteínas de Fímbrias/genética , Deleção de Genes , Manosídeos/uso terapêutico , Camundongos , Camundongos Endogâmicos C57BL , Peso Molecular , Combinação Trimetoprima e Sulfametoxazol/uso terapêutico , Bexiga Urinária/efeitos dos fármacos , Bexiga Urinária/microbiologia , Cateteres Urinários/microbiologia , Infecções Urinárias/microbiologia , Escherichia coli Uropatogênica/crescimento & desenvolvimento , Escherichia coli Uropatogênica/patogenicidade
4.
J Med Chem ; 55(8): 3945-59, 2012 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-22449031

RESUMO

Herein, we describe the X-ray structure-based design and optimization of biaryl mannoside FimH inhibitors. Diverse modifications to the biaryl ring to improve druglike physical and pharmacokinetic properties of mannosides were assessed for FimH binding affinity based on their effects on hemagglutination and biofilm formation along with direct FimH binding assays. Substitution on the mannoside phenyl ring ortho to the glycosidic bond results in large potency enhancements several-fold higher than those of corresponding unsubstituted matched pairs and can be rationalized from increased hydrophobic interactions with the FimH hydrophobic ridge (Ile13) or "tyrosine gate" (Tyr137 and Tyr48) also lined by Ile52. The lead mannosides have increased metabolic stability and oral bioavailability as determined from in vitro PAMPA predictive model of cellular permeability and in vivo pharmacokinetic studies in mice, thereby representing advanced preclinical candidates with promising potential as novel therapeutics for the clinical treatment and prevention of recurring urinary tract infections.


Assuntos
Compostos de Bifenilo/farmacologia , Proteínas de Fímbrias/antagonistas & inibidores , Manosídeos/farmacologia , Adesinas de Escherichia coli , Animais , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Compostos de Bifenilo/síntese química , Compostos de Bifenilo/farmacocinética , Testes de Inibição da Hemaglutinação , Manosídeos/síntese química , Manosídeos/química , Manosídeos/farmacocinética , Camundongos , Relação Estrutura-Atividade , Infecções Urinárias
5.
Chemistry ; 18(15): 4522-32, 2012 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-22431310

RESUMO

Pilicides and curlicides are compounds that block the formation of the virulence factors pili and curli, respectively. To facilitate studies of the interaction between these compounds and the pili and curli assembly systems, fluorescent pilicides and curlicides have been synthesized. This was achieved by using a strategy based on structure-activity knowledge, in which key pilicide and curlicide substituents on the ring-fused dihydrothiazolo 2-pyridone central fragment were replaced by fluorophores. Several of the resulting fluorescent compounds had improved activities as measured in pili- and curli-dependent biofilm assays. We created fluorescent pilicides and curlicides by introducing coumarin and 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) fluorophores at two positions on the peptidomimetic pilicide and curlicide central fragment. Fluorescence images of the uropathogenic Escherichia coli (UPEC) strain UTI89 grown in the presence of these compounds shows that the compounds are strongly associated with the bacteria with a heterogeneous distribution.


Assuntos
Antibacterianos/química , Antibacterianos/síntese química , Compostos de Boro/química , Compostos de Boro/síntese química , Cumarínicos/química , Proteínas de Escherichia coli/química , Escherichia coli/química , Corantes Fluorescentes/química , Corantes Fluorescentes/síntese química , Cristalografia por Raios X , Escherichia coli/patogenicidade , Modelos Moleculares , Relação Estrutura-Atividade , Virulência
6.
Sci Transl Med ; 3(109): 109ra115, 2011 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-22089451

RESUMO

Chronic and recurrent urinary tract infections pose a serious medical problem because there are few effective treatment options. Patients with chronic urinary tract infections are commonly treated with long-term prophylactic antibiotics that promote the development of antibiotic-resistant forms of uropathogenic Escherichia coli (UPEC), further complicating treatment. We developed small-molecular weight compounds termed mannosides that specifically inhibit the FimH type 1 pilus lectin of UPEC, which mediates bacterial colonization, invasion, and formation of recalcitrant intracellular bacterial communities in the bladder epithelium. Here, we optimized these compounds for oral bioavailability and demonstrated their fast-acting efficacy in treating chronic urinary tract infections in a preclinical murine model. These compounds also prevented infection in vivo when given prophylactically and strongly potentiated the activity of the current standard of care therapy, trimethoprim-sulfamethoxazole, against clinically resistant PBC-1 UPEC bacteria. These compounds have therapeutic efficacy after oral administration for the treatment of established urinary tract infections in vivo. Their unique mechanism of action-targeting the pilus tip adhesin FimH-circumvents the conventional requirement for drug penetration of the outer membrane, minimizing the potential for the development of resistance. The small-molecular weight compounds described herein promise to provide substantial benefit to women suffering from chronic and recurrent urinary tract infections.


Assuntos
Antibacterianos/farmacocinética , Antibacterianos/uso terapêutico , Proteínas de Fímbrias/antagonistas & inibidores , Infecções Urinárias/tratamento farmacológico , Escherichia coli Uropatogênica/patogenicidade , Adesinas de Escherichia coli , Animais , Antibacterianos/síntese química , Antibacterianos/química , Feminino , Espectroscopia de Ressonância Magnética , Manosídeos/síntese química , Manosídeos/química , Manosídeos/farmacocinética , Manosídeos/uso terapêutico , Camundongos , Microscopia Confocal , Estrutura Molecular , Escherichia coli Uropatogênica/efeitos dos fármacos
7.
J Med Chem ; 53(12): 4779-92, 2010 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-20507142

RESUMO

FimH-mediated cellular adhesion to mannosylated proteins is critical in the ability of uropathogenic E. coli (UPEC) to colonize and invade the bladder epithelium during urinary tract infection. We describe the discovery and optimization of potent small-molecule FimH bacterial adhesion antagonists based on alpha-d-mannose 1-position anomeric glycosides using X-ray structure-guided drug design. Optimized biarylmannosides display low nanomolar binding affinity for FimH in a fluorescence polarization assay and submicromolar cellular activity in a hemagglutination (HA) functional cell assay of bacterial adhesion. X-ray crystallography demonstrates that the biphenyl moiety makes several key interactions with the outer surface of FimH including pi-pi interactions with Tyr-48 and an H-bonding electrostatic interaction with the Arg-98/Glu-50 salt bridge. Dimeric analogues linked through the biaryl ring show an impressive 8-fold increase in potency relative to monomeric matched pairs and represent the most potent FimH antagonists identified to date. The FimH antagonists described herein hold great potential for development as novel therapeutics for the effective treatment of urinary tract infections.


Assuntos
Antibacterianos/síntese química , Proteínas de Fímbrias/antagonistas & inibidores , Manosídeos/síntese química , Adesinas de Escherichia coli , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Ligação Competitiva , Cristalografia por Raios X , Desenho de Fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Polarização de Fluorescência , Cobaias , Testes de Hemaglutinação , Ligação de Hidrogênio , Manosídeos/química , Manosídeos/farmacologia , Modelos Moleculares , Ligação Proteica , Relação Estrutura-Atividade
8.
Infect Immun ; 78(4): 1457-67, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20123719

RESUMO

Urinary tract infections (UTIs), the majority of which are caused by uropathogenic Escherichia coli (UPEC), afflict nearly 60% of women within their lifetimes. Studies in mice and humans have revealed that UPEC strains undergo a complex pathogenesis cycle that involves both the formation of intracellular bacterial communities (IBC) and the colonization of extracellular niches. Despite the commonality of the UPEC pathogenesis cycle, no specific urovirulence genetic profile has been determined; this is likely due to the fluid nature of the UPEC genome as the result of horizontal gene transfer and numerous genes of unknown function. UTI89 has a large extrachromosomal element termed pUTI89 with many characteristics of UPEC pathogenicity islands and that likely arose due to horizontal gene transfer. The pUTI89 plasmid has characteristics of both F plasmids and other known virulence plasmids. We sought to determine whether pUTI89 is important for virulence. Both in vitro and in vivo assays were used to examine the function of pUTI89 using plasmid-cured UTI89. No differences were observed between UTI89 and plasmid-cured UTI89 based on growth, type 1 pilus expression, or biofilm formation. However, in a mouse model of UTI, a significant decrease in bacterial invasion, CFU and IBC formation of the pUTI89-cured strain was observed at early time points postinfection compared to the wild type. Through directed deletions of specific operons on pUTI89, the cjr operon was partially implicated in this observed defect. Our findings implicate pUTI89 in the early aspects of infection.


Assuntos
Proteínas de Escherichia coli/fisiologia , Plasmídeos , Escherichia coli Uropatogênica/patogenicidade , Fatores de Virulência/fisiologia , Animais , Contagem de Colônia Microbiana , Modelos Animais de Doenças , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Feminino , Técnicas de Inativação de Genes , Camundongos , Camundongos Endogâmicos C3H , Óperon , Bexiga Urinária/microbiologia , Infecções Urinárias/microbiologia , Virulência , Fatores de Virulência/genética
9.
Proc Natl Acad Sci U S A ; 106(52): 22439-44, 2009 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-20018753

RESUMO

FimH, the type 1 pilus adhesin of uropathogenic Escherichia coli (UPEC), contains a receptor-binding domain with an acidic binding pocket specific for mannose. The fim operon, and thus type 1 pilus production, is under transcriptional control via phase variation of an invertible promoter element. FimH is critical during urinary tract infection for mediating colonization and invasion of the bladder epithelium and establishment of intracellular bacterial communities (IBCs). In silico analysis of FimH gene sequences from 279 E. coli strains identified specific amino acids evolving under positive selection outside of its mannose-binding pocket. Mutating two of these residues (A27V/V163A) had no effect on phase variation, pilus assembly, or mannose binding in vitro. However, compared to wild-type, this double mutant strain exhibited a 10,000-fold reduction in mouse bladder colonization 24 h after inoculation and was unable to form IBCs even though it bound normally to mannosylated receptors in the urothelium. In contrast, the single A62S mutation altered phase variation, reducing the proportion of piliated cells, reduced mannose binding 8-fold, and decreased bladder colonization 30-fold in vivo compared to wild-type. A phase-locked ON A62S mutant restored virulence to wild-type levels even though in vitro mannose binding remained impaired. Thus, positive selection analysis of FimH has separated mannose binding from in vivo fitness, suggesting that IBC formation is critical for successful infection of the mammalian bladder, providing support for more general use of in silico positive selection analysis to define the molecular underpinnings of bacterial pathogenesis.


Assuntos
Adesinas de Escherichia coli/genética , Adesinas de Escherichia coli/fisiologia , Infecções por Escherichia coli/metabolismo , Infecções por Escherichia coli/microbiologia , Proteínas de Fímbrias/genética , Proteínas de Fímbrias/fisiologia , Manose/metabolismo , Infecções Urinárias/metabolismo , Infecções Urinárias/microbiologia , Escherichia coli Uropatogênica/fisiologia , Escherichia coli Uropatogênica/patogenicidade , Adesinas de Escherichia coli/química , Substituição de Aminoácidos , Animais , Proteínas de Fímbrias/química , Genes Bacterianos , Camundongos , Camundongos Endogâmicos C3H , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Mutação , Filogenia , Seleção Genética , Bexiga Urinária/microbiologia , Escherichia coli Uropatogênica/genética , Virulência/genética , Virulência/fisiologia
10.
Nat Chem Biol ; 5(12): 913-9, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19915538

RESUMO

Curli are functional extracellular amyloid fibers produced by uropathogenic Escherichia coli (UPEC) and other Enterobacteriaceae. Ring-fused 2-pyridones, such as FN075 and BibC6, inhibited curli biogenesis in UPEC and prevented the in vitro polymerization of the major curli subunit protein CsgA. The curlicides FN075 and BibC6 share a common chemical lineage with other ring-fused 2-pyridones termed pilicides. Pilicides inhibit the assembly of type 1 pili, which are required for pathogenesis during urinary tract infection. Notably, the curlicides retained pilicide activities and inhibited both curli-dependent and type 1-dependent biofilms. Furthermore, pretreatment of UPEC with FN075 significantly attenuated virulence in a mouse model of urinary tract infection. Curli and type 1 pili exhibited exclusive and independent roles in promoting UPEC biofilms, and curli provided a fitness advantage in vivo. Thus, the ability of FN075 to block the biogenesis of both curli and type 1 pili endows unique anti-biofilm and anti-virulence activities on these compounds.


Assuntos
Amiloide/biossíntese , Proteínas de Bactérias/biossíntese , Biofilmes/crescimento & desenvolvimento , Proteínas de Escherichia coli/biossíntese , Bibliotecas de Moléculas Pequenas/farmacologia , Escherichia coli Uropatogênica/metabolismo , Amiloide/antagonistas & inibidores , Animais , Aderência Bacteriana/efeitos dos fármacos , Proteínas de Bactérias/antagonistas & inibidores , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/microbiologia , Escherichia coli K12/crescimento & desenvolvimento , Escherichia coli K12/metabolismo , Escherichia coli K12/patogenicidade , Proteínas de Escherichia coli/antagonistas & inibidores , Camundongos , Estrutura Molecular , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/uso terapêutico , Infecções Urinárias/tratamento farmacológico , Infecções Urinárias/microbiologia , Escherichia coli Uropatogênica/crescimento & desenvolvimento , Escherichia coli Uropatogênica/patogenicidade , Virulência
11.
IDrugs ; 12(11): 699-705, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19844856

RESUMO

The prevalence of antibiotic resistance among microorganisms that cause infectious diseases has resulted in the need to devise new strategies for the development of novel therapeutics. In an effort to thwart antibiotic resistance, novel therapeutics are being developed that target bacterial virulence factors as an alternative to traditional antibiotics, which target essential microbial processes, thereby promoting bacterial evolution and resulting in resistance. While many antivirulence targets exist, this feature review focuses on adhesion as an antivirulence target, using pili of uropathogenic Escherichia coli as a model system. The two strategies of drug development discussed in this review involve the inhibition of bacterial binding to the host tissue by the addition of exogenous sugars, and the disruption of chaperone-usher (CU) pilus assembly through the disruption of protein-protein interactions. However, because of the commonality of adhesion to infectious disease processes and CU pili to many pathogens, the two strategies are translatable to a multitude of organisms.


Assuntos
Antibacterianos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Infecções Bacterianas/tratamento farmacológico , Animais , Bactérias/efeitos dos fármacos , Bactérias/patogenicidade , Infecções Bacterianas/microbiologia , Sistemas de Liberação de Medicamentos , Desenho de Fármacos , Farmacorresistência Bacteriana , Escherichia coli/efeitos dos fármacos , Escherichia coli/patogenicidade , Humanos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...