Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 142
Filtrar
1.
Proc Natl Acad Sci U S A ; 120(36): e2309389120, 2023 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-37639602

RESUMO

The amyloid-beta peptide (Aß) is a driver of Alzheimer's disease (AD). Aß monomers can aggregate and form larger soluble (oligomers/protofibrils) and insoluble (fibrils) forms. There is evidence that Aß protofibrils are the most toxic form, but the reasons are not known. Consistent with a critical role for this form of Aß in AD, a recently FDA-approved therapeutic antibody targeted against protofibrils, lecanemab, slows the progression of AD in patients. The plasma contact system, which can promote coagulation and inflammation, has been implicated in AD pathogenesis. This system is activated by Aß which could lead to vascular and inflammatory pathologies associated with AD. We show here that the contact system is preferentially activated by protofibrils of Aß. Aß protofibrils bind to coagulation factor XII and high molecular weight kininogen and accelerate the activation of the system. Furthermore, lecanemab blocks Aß protofibril activation of the contact system. This work provides a possible mechanism for Aß protofibril toxicity in AD and why lecanemab is therapeutically effective.


Assuntos
Doença de Alzheimer , Humanos , Peptídeos beta-Amiloides/toxicidade , Coagulação Sanguínea , Citoesqueleto , Fator XII
2.
Am J Respir Crit Care Med ; 205(5): 529-539, 2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-34784492

RESUMO

Rationale: The cystic fibrosis (CF) modulator drug, elexacaftor/tezacaftor/ivacaftor (ETI), proved highly effective in controlled clinical trials for individuals with at least one F508del allele, which occurs in at least 85% of people with CF. Objectives: PROMISE is a postapproval study to understand the broad effects of ETI through 30 months' clinical use in a more diverse U.S. patient population with planned analyses after 6 months. Methods: Prospective, observational study in 487 people with CF age 12 years or older with at least one F508del allele starting ETI for the first time. Assessments occurred before and 1, 3, and 6 months into ETI therapy. Outcomes included change in percent predicted FEV1 (ppFEV1), sweat chloride concentration, body mass index (BMI), and self-reported respiratory symptoms. Measurements and Main Results: Average age was 25.1 years, and 44.1% entered the study using tezacaftor/ivacaftor or lumacaftor/ivacaftor, whereas 6.7% were using ivacaftor, consistent with F508del homozygosity and G551D allele, respectively. At 6 months into ETI therapy, ppFEV1 improved 9.76 percentage points (95% confidence interval [CI], 8.76 to 10.76) from baseline, cystic fibrosis questionnaire-revised respiratory domain score improved 20.4 points (95% CI, 18.3 to 22.5), and sweat chloride decreased -41.7 mmol/L (95% CI, -43.8 to -39.6). BMI also significantly increased. Changes were larger in those naive to modulators but substantial in all groups, including those treated with ivacaftor at baseline. Conclusions: ETI by clinical prescription provided large improvements in lung function, respiratory symptoms, and BMI in a diverse population naive to modulator drug therapy, using existing two-drug combinations, or using ivacaftor alone. Each group also experienced significant reductions in sweat chloride concentration, which correlated with improved ppFEV1 in the overall study population. Clinical trial registered with www.clinicaltrials.gov (NCT NCT04038047).


Assuntos
Fibrose Cística , Adulto , Aminofenóis/uso terapêutico , Benzodioxóis/uso terapêutico , Criança , Agonistas dos Canais de Cloreto/uso terapêutico , Cloretos/análise , Fibrose Cística/tratamento farmacológico , Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística , Combinação de Medicamentos , Humanos , Indóis , Mutação , Estudos Prospectivos , Pirazóis , Piridinas , Pirrolidinas , Quinolonas , Resultado do Tratamento
3.
Thorax ; 77(6): 581-588, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-34706982

RESUMO

RATIONALE: Inhaled tobramycin and oral azithromycin are common chronic therapies in people with cystic fibrosis and Pseudomonas aeruginosa airway infection. Some studies have shown that azithromycin can reduce the ability of tobramycin to kill P. aeruginosa. This trial was done to test the effects of combining azithromycin with inhaled tobramycin on clinical and microbiological outcomes in people already using inhaled tobramycin. We theorised that those randomised to placebo (no azithromycin) would have greater improvement in forced expiratory volume in one second (FEV1) and greater reduction in P. aeruginosa sputum in response to tobramycin. METHODS: A 6-week prospective, randomised, placebo-controlled, double-blind trial testing oral azithromycin versus placebo combined with clinically prescribed inhaled tobramycin in individuals with cystic fibrosis and P. aeruginosa airway infection. RESULTS: Over a 6-week period, including 4 weeks of inhaled tobramycin, the relative change in FEV1 did not statistically significantly differ between groups (azithromycin (n=56) minus placebo (n=52) difference: 3.44%; 95% CI: -0.48 to 7.35; p=0.085). Differences in secondary clinical outcomes, including patient-reported symptom scores, weight and need for additional antibiotics, did not significantly differ. Among the 29 azithromycin and 35 placebo participants providing paired sputum samples, the 6-week change in P. aeruginosa density differed in favour of the placebo group (difference: 0.75 log10 CFU/mL; 95% CI: 0.03 to 1.47; p=0.043). CONCLUSIONS: Despite having greater reduction in P. aeruginosa density in participants able to provide sputum samples, participants randomised to placebo with inhaled tobramycin did not experience significantly greater improvements in lung function or other clinical outcomes compared with those randomised to azithromycin with tobramycin.


Assuntos
Fibrose Cística , Infecções por Pseudomonas , Administração por Inalação , Antibacterianos/uso terapêutico , Azitromicina , Fibrose Cística/complicações , Fibrose Cística/tratamento farmacológico , Volume Expiratório Forçado , Humanos , Estudos Prospectivos , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa , Tobramicina
4.
Environ Res ; 204(Pt D): 112382, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34793761

RESUMO

In coal, total sulphur content is not the only important factor for the industry, but also the forms of sulphur and their distributions should be considered before utilizing any coal for a particular use. In Jharia and Raniganj coalfields, sulphur is present in the forms of organic sulphur (OS), pyritic sulphur (PS), and sulphate sulphur (SS). In this perspective, the present study aims to know the different forms of sulphur in coking and non-coking coals of Jharia and Raniganj coalfields. Twenty samples were collected from both the mining areas. The total sulphur content in coking coals varied from 0.28% to 0.55% and in non-coking coals it varied from 0.33% to 0.54%. The distribution pattern of sulphur showed that PS and OS are dominating in both the coalfields. The OS in Jharia field varied from 0.13% to 0.47%, and in Raniganj coalfield it varied from 0.19% to 0.41%. This depicts that both the coalfields were formed under freshwater condition. Similarly, PS varied from 0.01% to 0.21% and from 0.06% to 0.29%, and SS varied from 0.0052% to 0.01% and 0.005%-0.02% in the above fields, respectively. It is noticed that the content of sulphate sulphur is less than 0.1 wt%, which is lower than other forms of sulphur. In the past two decades, sulphur emission has increased with the increase of thermal power plants due to more demand for power, which is one of the causes of global warming. During coal combustion, H2S and SOx, are produced and that can react with O2 and H2O to form H2SO3, H2SO4 or H2S. Thus, sulphur release can respond within the ecosystem in the form of acidic precipitation that may acidify and affect lakes and streams, sub-surface water and historical monuments. In India, coal consumption and ecological contaminations are increasing day by day due to the rapid energy consumption. Therefore, special attention should be given to adopt clean coal technologies though the coal contains less sulphur.


Assuntos
Carvão Mineral , Ecossistema , Fracionamento Químico , Carvão Mineral/análise , Monitoramento Ambiental , Centrais Elétricas , Enxofre
5.
Bull Environ Contam Toxicol ; 108(3): 396-402, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33025110

RESUMO

Amelioration of mine soil is challenging because of the lack of biologically active organic matter. The study was aimed to recycle yard waste into compost and biochar and to use them to reclaim mine soil. Biochar prepared at 350 °C showed the highest stable organic matter yield index and was used for the experiments. Lady's finger was grown on mine soil amended with biochar (1%-5%), compost (2%-10%), and biochar-compost mixtures (2%-10%). Mine soil pH increased in all treatments. Mine soil dehydrogenase activity (42%-224%), microbial biomass carbon (4%-257%), and hydrolase activity (3%-230%) increased by combined application of biochar and compost. Lady's finger plant height, biomass, and fruit yield were superior in biochar-compost mixtures compared to biochar and compost alone treatment. Thus the use of compost along with biochar could be recommended for reclamation of mine soil.


Assuntos
Abelmoschus , Compostagem , Poluentes do Solo , Carvão Vegetal , Humanos , Solo , Poluentes do Solo/análise
6.
Artigo em Inglês | MEDLINE | ID: mdl-33318007

RESUMO

The approval of aztreonam lysine for inhalation solution (AZLI) raised concerns that additional antibiotic exposure would potentially affect the susceptibility profiles of Pseudomonas aeruginosa isolates from cystic fibrosis (CF) patients. This 5-year, prospective, observational study tracked susceptibility changes and clinical outcomes in CF patients in the United States with chronic P. aeruginosa infection. Sputum cultures were collected annually (2011 to 2016). The primary study endpoint was the proportion of subjects whose least susceptible P. aeruginosa isolate had an aztreonam MIC that was >8 µg/ml (parenteral breakpoint) and increased ≥4-fold compared with the least susceptible isolate from the previous year. Annualized data for pulmonary exacerbations, hospitalizations, and percent of predicted forced expiratory volume in 1 s (FEV1% predicted) were obtained from the CF Foundation Patient Registry and compared between subjects meeting and those not meeting the primary endpoint. A total of 510 subjects were enrolled; 334 (65%) completed the study. A consistent proportion of evaluable subjects (13 to 22%) met the primary endpoint each year, and AZLI use during the previous 12 months was not associated with meeting the primary endpoint. While the annual declines in lung function were comparable for subjects meeting and those not meeting the primary endpoint, more pulmonary exacerbations and hospitalizations were experienced by those who met it. The aztreonam susceptibility of P. aeruginosa remained consistent during the 5-year study. The relationship between P. aeruginosa isolate susceptibilities and clinical outcomes is complex; reduced susceptibility was not associated with an accelerated decline in lung function but was associated with more exacerbations and hospitalizations, likely reflecting increased overall antibiotic exposure. (This study has been registered at ClinicalTrials.gov under identifier NCT01375036.).


Assuntos
Fibrose Cística , Infecções por Pseudomonas , Administração por Inalação , Antibacterianos/uso terapêutico , Aztreonam/uso terapêutico , Fibrose Cística/tratamento farmacológico , Humanos , Lisina , Estudos Prospectivos , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa , Resultado do Tratamento
7.
PLoS Pathog ; 15(3): e1007511, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30893371

RESUMO

While much is known about acute infection pathogenesis, the understanding of chronic infections has lagged. Here we sought to identify the genes and functions that mediate fitness of the pathogen Pseudomonas aeruginosa in chronic wound infections, and to better understand the selective environment in wounds. We found that clinical isolates from chronic human wounds were frequently defective in virulence functions and biofilm formation, and that many virulence and biofilm formation genes were not required for bacterial fitness in experimental mouse wounds. In contrast, genes involved in anaerobic growth, some metabolic and energy pathways, and membrane integrity were critical. Consistent with these findings, the fitness characteristics of some wound impaired-mutants could be represented by anaerobic, oxidative, and membrane-stress conditions ex vivo, and more comprehensively by high-density bacterial growth conditions, in the absence of a host. These data shed light on the bacterial functions needed in chronic wound infections, the nature of stresses applied to bacteria at chronic infection sites, and suggest therapeutic targets that might compromise wound infection pathogenesis.


Assuntos
Proliferação de Células/fisiologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Cicatrização/fisiologia , Adulto , Animais , Bactérias/crescimento & desenvolvimento , Infecções Bacterianas/metabolismo , Biofilmes/crescimento & desenvolvimento , Modelos Animais de Doenças , Feminino , Aptidão Genética , Interações entre Hospedeiro e Microrganismos/fisiologia , Humanos , Masculino , Camundongos , Infecções por Pseudomonas , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/patogenicidade , Virulência/fisiologia , Infecção dos Ferimentos/metabolismo , Infecção dos Ferimentos/microbiologia
8.
Proc Natl Acad Sci U S A ; 115(42): 10780-10785, 2018 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-30275316

RESUMO

Bacteria causing chronic infections are generally observed living in cell aggregates suspended in polymer-rich host secretions, and bacterial phenotypes induced by aggregated growth may be key factors in chronic infection pathogenesis. Bacterial aggregation is commonly thought of as a consequence of biofilm formation; however the mechanisms producing aggregation in vivo remain unclear. Here we show that polymers that are abundant at chronic infection sites cause bacteria to aggregate by the depletion aggregation mechanism, which does not require biofilm formation functions. Depletion aggregation is mediated by entropic forces between uncharged or like-charged polymers and particles (e.g., bacteria). Our experiments also indicate that depletion aggregation of bacteria induces marked antibiotic tolerance that was dependent on the SOS response, a stress response activated by genotoxic stress. These findings raise the possibility that targeting conditions that promote depletion aggregation or mechanisms of depletion-mediated tolerance could lead to new therapeutic approaches to combat chronic bacterial infections.


Assuntos
Antibacterianos/farmacologia , Tolerância a Medicamentos , Entropia , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/química , Pseudomonas aeruginosa/efeitos dos fármacos , Biofilmes , Humanos , Testes de Sensibilidade Microbiana , Fenótipo , Pseudomonas aeruginosa/isolamento & purificação
9.
Proc Natl Acad Sci U S A ; 115(29): E6863-E6870, 2018 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-29967165

RESUMO

We describe noncovalent, reversible asparagine ethylenediamine (AsnEDA) inhibitors of the Plasmodium falciparum proteasome (Pf20S) ß5 subunit that spare all active subunits of human constitutive and immuno-proteasomes. The compounds are active against erythrocytic, sexual, and liver-stage parasites, against parasites resistant to current antimalarials, and against P. falciparum strains from patients in Africa. The ß5 inhibitors synergize with a ß2 inhibitor in vitro and in mice and with artemisinin. P. falciparum selected for resistance to an AsnEDA ß5 inhibitor surprisingly harbored a point mutation in the noncatalytic ß6 subunit. The ß6 mutant was resistant to the species-selective Pf20S ß5 inhibitor but remained sensitive to the species-nonselective ß5 inhibitors bortezomib and carfilzomib. Moreover, resistance to the Pf20S ß5 inhibitor was accompanied by increased sensitivity to a Pf20S ß2 inhibitor. Finally, the ß5 inhibitor-resistant mutant had a fitness cost that was exacerbated by irradiation. Thus, used in combination, multistage-active inhibitors of the Pf20S ß5 and ß2 subunits afford synergistic antimalarial activity with a potential to delay the emergence of resistance to artemisinins and each other.


Assuntos
Antimaláricos/química , Plasmodium falciparum/enzimologia , Complexo de Endopeptidases do Proteassoma/química , Inibidores de Proteassoma/química , Proteínas de Protozoários/antagonistas & inibidores , Artemisininas/química , Bortezomib/química , Resistência Microbiana a Medicamentos , Humanos , Lactonas/química , Oligopeptídeos/química , Proteínas de Protozoários/química
10.
Neurobiol Dis ; 139: 104833, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32173555

RESUMO

Alzheimer's disease (AD) is characterized by the presence of proteinaceous brain deposits, brain atrophy, vascular dysfunction, and chronic inflammation. Along with cerebral inflammation, peripheral inflammation is also evident in many AD patients. Bradykinin, a proinflammatory plasma peptide, is also linked to AD pathology. For example, bradykinin infusion into the hippocampus causes learning and memory deficits in rats, and blockade of the bradykinin receptor lessens cognitive impairment in AD mouse models. Even though it has been hypothesized that plasma bradykinin could contribute to inflammation in AD, the level of plasma bradykinin and its association with beta-amyloid (Aß) pathology in AD patients had not been explored. Here, we assessed plasma bradykinin levels in AD patients and age-matched non-demented (ND) control individuals. We found significantly elevated plasma bradykinin levels in AD patients compared to ND subjects. Additionally, changes in plasma bradykinin levels were more profound in many AD patients with severe cognitive impairment, suggesting that peripheral bradykinin could play a role in dementia most likely via inflammation. Bradykinin levels in the cerebrospinal fluid (CSF) were reduced in AD patients and exhibited an inverse correlation with the CSF Aß40/Aß42 ratio. We also report that bradykinin interacts with the fibrillar form of Aß and co-localizes with Aß plaques in the post-mortem human AD brain. These findings connect the peripheral inflammatory pathway to cerebral abnormalities and identify a novel mechanism of inflammatory pathology in AD.


Assuntos
Doença de Alzheimer/sangue , Bradicinina/sangue , Disfunção Cognitiva/sangue , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/líquido cefalorraquidiano , Peptídeos beta-Amiloides/sangue , Apolipoproteínas E/líquido cefalorraquidiano , Biomarcadores/sangue , Bradicinina/líquido cefalorraquidiano , Estudos de Casos e Controles , Disfunção Cognitiva/líquido cefalorraquidiano , Progressão da Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Placa Amiloide/sangue
11.
J Proteome Res ; 18(6): 2601-2612, 2019 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-31060355

RESUMO

Chronic airway infection with P. aeruginosa (PA) is a hallmark of cystic fibrosis (CF) disease. The mechanisms producing PA persistence in CF therapies remain poorly understood. To gain insight on PA physiology in patient airways and better understand how in vivo bacterial functioning differs from in vitro conditions, we investigated the in vivo proteomes of PA in 35 sputum samples from 11 CF patients. We developed a novel bacterial-enrichment method that relies on differential centrifugation and detergent treatment to enrich for bacteria to improve identification of PA proteome with CF sputum samples. Using two nonredundant peptides as a cutoff, a total of 1304 PA proteins were identified directly from CF sputum samples. The in vivo PA proteomes were compared with the proteomes of ex vivo-grown PA populations from the same patient sample. Label-free quantitation and proteome comparison revealed the in vivo up-regulation of siderophore TonB-dependent receptors, remodeling in central carbon metabolism including glyoxylate cycle and lactate utilization, and alginate overproduction. Knowledge of these in vivo proteome differences or others derived using the presented methodology could lead to future treatment strategies aimed at altering PA physiology in vivo to compromise infectivity or improve antibiotic efficacy.


Assuntos
Fibrose Cística/diagnóstico , Proteoma/genética , Infecções por Pseudomonas/diagnóstico , Pseudomonas aeruginosa/isolamento & purificação , Adulto , Antibacterianos/uso terapêutico , Proteínas de Bactérias/genética , Carbono/metabolismo , Fibrose Cística/tratamento farmacológico , Fibrose Cística/genética , Fibrose Cística/microbiologia , Feminino , Glioxilatos/metabolismo , Humanos , Ácido Láctico/metabolismo , Masculino , Proteínas de Membrana/genética , Pessoa de Meia-Idade , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/genética , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/patogenicidade , Escarro/microbiologia
12.
J Antimicrob Chemother ; 74(5): 1260-1268, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30753525

RESUMO

OBJECTIVES: The emergence of fluconazole resistance in Candida parapsilosis healthcare-associated infections has recently been increasingly reported. Antifungal susceptibility profiles and mechanisms of fluconazole resistance in C. parapsilosis (n = 199) from nine hospitals in India collected over a period of 3 years were studied. Further, clonal transmission of fluconazole-resistant isolates in different hospitals was investigated. METHODS: Antifungal susceptibility testing of five azoles, amphotericin B and 5-flucytosine was performed by the CLSI microbroth dilution method. The azole target ERG11 gene was sequenced, and the significance of a novel ERG11 mutation in C. parapsilosis was determined using a gap-repair cloning approach in Saccharomyces cerevisiae. In addition, microsatellite analysis was performed to determine the clonal lineage of C. parapsilosis-resistant strains circulating among different hospitals. RESULTS: A total of 64 (32%) C. parapsilosis isolates were non-susceptible to fluconazole, which included resistant (n = 55; MIC >4 mg/L) and susceptible dose-dependent (n = 9) isolates. Of these 64 non-susceptible isolates, a novel K143R amino acid substitution was noted in 92%, and the remaining five isolates had the Y132F substitution. Elevated azole MICs (≥16-fold) were detected in S. cerevisiae upon expression of C. parapsilosis ERG11 alleles carrying Y132F or K143R substitutions. Two major clusters of non-susceptible isolates were circulating in seven Indian hospitals. CONCLUSIONS: We report a novel K143R amino acid substitution in ERG11p causing fluconazole resistance in C. parapsilosis. Fluconazole-non-susceptible C. parapsilosis isolates carrying the novel K143R amino acid substitution should be identified in clinical microbiology laboratories to prevent further clonal transmission.


Assuntos
Antifúngicos/farmacologia , Candida parapsilosis/efeitos dos fármacos , Candidíase/microbiologia , Farmacorresistência Fúngica , Fluconazol/farmacologia , Substituição de Aminoácidos , Candida parapsilosis/genética , Candidíase/tratamento farmacológico , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Amplificação de Genes , Humanos , Índia/epidemiologia , Testes de Sensibilidade Microbiana , Repetições de Microssatélites , Mutação , Filogenia
14.
Mycoses ; 62(1): 11-15, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30367553

RESUMO

The taxonomy of the dermatophytes has been revisited using a novel multilocus phylogenetic approach, and several neotypes and reference strains have been assigned for Trichophyton species. Single gene sequencing, that is the ITS region, for identification of highly related species T. mentagrophytes/T. interdigitale, warrant reassessment. The sequence database (Westerdijk and NCBI) needs to be updated as several incorrect/obsolete entries of reference and neotype strains of T. interdigitale/T. mentagrophytes hampers correct identification of this complex.


Assuntos
Erros de Diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Tinha/diagnóstico , Tinha/microbiologia , Trichophyton/classificação , Trichophyton/genética , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Humanos , Filogenia , Análise de Sequência de DNA
15.
Proc Natl Acad Sci U S A ; 113(52): E8425-E8432, 2016 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-27956634

RESUMO

Constitutive proteasomes (c-20S) are ubiquitously expressed cellular proteases that degrade polyubiquitinated proteins and regulate cell functions. An isoform of proteasome, the immunoproteasome (i-20S), is highly expressed in human T cells, dendritic cells (DCs), and B cells, suggesting that it could be a potential target for inflammatory diseases, including those involving autoimmunity and alloimmunity. Here, we describe DPLG3, a rationally designed, noncovalent inhibitor of the immunoproteasome chymotryptic subunit ß5i that has thousands-fold selectivity over constitutive ß5c. DPLG3 suppressed cytokine release from blood mononuclear cells and the activation of DCs and T cells, diminished accumulation of effector T cells, promoted expression of exhaustion and coinhibitory markers on T cells, and synergized with CTLA4-Ig to promote long-term acceptance of cardiac allografts across a major histocompatibility barrier. These findings demonstrate the potential value of using brief posttransplant immunoproteasome inhibition to entrain a long-term response favorable to allograft survival as part of an immunomodulatory regimen that is neither broadly immunosuppressive nor toxic.


Assuntos
Sobrevivência de Enxerto , Transplante de Coração/métodos , Imunossupressores/farmacologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , Animais , Linhagem Celular Tumoral , Proliferação de Células , Citocinas/imunologia , Células Dendríticas/citologia , Células Dendríticas/imunologia , Células Hep G2 , Humanos , Memória Imunológica , Leucócitos Mononucleares/citologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Linfócitos T/imunologia
16.
Proc Natl Acad Sci U S A ; 113(7): 1778-83, 2016 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-26831078

RESUMO

Cancer cells reprogram their metabolism to promote growth and proliferation. The genetic evidence pointing to the importance of the amino acid serine in tumorigenesis is striking. The gene encoding the enzyme 3-phosphoglycerate dehydrogenase (PHGDH), which catalyzes the first committed step of serine biosynthesis, is overexpressed in tumors and cancer cell lines via focal amplification and nuclear factor erythroid-2-related factor 2 (NRF2)-mediated up-regulation. PHGDH-overexpressing cells are exquisitely sensitive to genetic ablation of the pathway. Here, we report the discovery of a selective small molecule inhibitor of PHGDH, CBR-5884, identified by screening a library of 800,000 drug-like compounds. CBR-5884 inhibited de novo serine synthesis in cancer cells and was selectively toxic to cancer cell lines with high serine biosynthetic activity. Biochemical characterization of the inhibitor revealed that it was a noncompetitive inhibitor that showed a time-dependent onset of inhibition and disrupted the oligomerization state of PHGDH. The identification of a small molecule inhibitor of PHGDH not only enables thorough preclinical evaluation of PHGDH as a target in cancers, but also provides a tool with which to study serine metabolism.


Assuntos
Neoplasias/metabolismo , Fosfoglicerato Desidrogenase/antagonistas & inibidores , Serina/biossíntese , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Neoplasias/patologia
17.
Molecules ; 24(8)2019 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-31022852

RESUMO

Determining chemokine receptor CXCR4 expression is significant in multiple diseases due to its role in promoting inflammation, cell migration and tumorigenesis. [68Ga]Pentixafor is a promising ligand for imaging CXCR4 expression in multiple tumor types, but its utility is limited by the physical properties of 68Ga. We screened a library of >200 fluorine-containing structural derivatives of AMD-3465 to identify promising candidates for in vivo imaging of CXCR4 expression by positron emission tomography (PET). Compounds containing fluoroethyltriazoles consistently achieved higher docking scores. Six of these higher scoring compounds were radiolabeled by click chemistry and evaluated in PC3-CXCR4 cells and BALB/c mice bearing bilateral PC3-WT and PC3-CXCR4 xenograft tumors. The apparent CXCR4 affinity of the ligands was relatively low, but tumor uptake was CXCR4-specific. The tumor uptake of [18F]RPS-534 (7.2 ± 0.3 %ID/g) and [18F]RPS-547 (3.1 ± 0.5 %ID/g) at 1 h p.i. was highest, leading to high tumor-to-blood, tumor-to-muscle, and tumor-to-lung ratios. Total cell-associated activity better predicted in vivo tumor uptake than did the docking score or apparent CXCR4 affinity. By this metric, and on the basis of their high yielding radiosynthesis, high tumor uptake, and good contrast to background, [18F]RPS-547, and especially [18F]RPS-534, are promising 18F-labeled candidates for imaging CXCR4 expression.


Assuntos
Complexos de Coordenação/administração & dosagem , Imagem Molecular , Peptídeos Cíclicos/administração & dosagem , Compostos Radiofarmacêuticos/administração & dosagem , Receptores CXCR4/genética , Animais , Linhagem Celular Tumoral , Complexos de Coordenação/química , Radioisótopos de Flúor/química , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Ligantes , Camundongos , Peptídeos Cíclicos/química , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos/química , Receptores CXCR4/química , Ensaios Antitumorais Modelo de Xenoenxerto
18.
Biochemistry ; 57(8): 1399-1409, 2018 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-29394041

RESUMO

Accumulating evidence suggests that fibrinogen, a key protein in the coagulation cascade, plays an important role in circulatory dysfunction in Alzheimer's disease (AD). Previous work has shown that the interaction between fibrinogen and ß-amyloid (Aß), a hallmark pathological protein in AD, induces plasmin-resistant abnormal blood clots, delays fibrinolysis, increases inflammation, and aggravates cognitive function in mouse models of AD. Since Aß oligomers have a much stronger affinity for fibrinogen than Aß monomers, we tested whether amyloid aggregation inhibitors could block the Aß-fibrinogen interaction and found that some Aß aggregation inhibitors showed moderate inhibitory efficacy against this interaction. We then modified a hit compound so that it not only showed a strong inhibitory efficacy toward the Aß-fibrinogen interaction but also retained its potency toward the Aß42 aggregation inhibition process. Furthermore, our best hit compound, TDI-2760, modulated Aß42-induced contact system activation, a pathological condition observed in some AD patients, in addition to inhibiting the Aß-fibrinogen interaction and Aß aggregation. Thus, TDI-2760 has the potential to lessen vascular abnormalities as well as Aß aggregation-driven pathology in AD.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Fibrinogênio/metabolismo , Fragmentos de Peptídeos/metabolismo , Agregados Proteicos/efeitos dos fármacos , Mapas de Interação de Proteínas/efeitos dos fármacos , Pirimidinas/química , Pirimidinas/farmacologia , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Desenho de Fármacos , Humanos , Agregação Patológica de Proteínas/tratamento farmacológico , Agregação Patológica de Proteínas/metabolismo
19.
Thorax ; 73(2): 134-144, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28916704

RESUMO

BACKGROUND: Cystic fibrosis (CF) lung disease is defined by large numbers of neutrophils and associated damaging products in the airway. Delayed neutrophil apoptosis is described in CF although it is unclear whether this is a primary neutrophil defect or a response to chronic inflammation. Increased levels of neutrophil extracellular traps (NETs) have been measured in CF and we aimed to investigate the causal relationship between these phenomena and their potential to serve as a driver of inflammation. We hypothesised that the delay in apoptosis in CF is a primary defect and preferentially allows CF neutrophils to form NETs, contributing to inflammation. METHODS: Blood neutrophils were isolated from patients with CF, CF pigs and appropriate controls. Neutrophils were also obtained from patients with CF before and after commencing ivacaftor. Apoptosis was assessed by morphology and flow cytometry. NET formation was determined by fluorescent microscopy and DNA release assays. NET interaction with macrophages was examined by measuring cytokine generation with ELISA and qRT-PCR. RESULTS: CF neutrophils live longer due to decreased apoptosis. This was observed in both cystic fibrosis transmembrane conductance regulator (CFTR) null piglets and patients with CF, and furthermore was reversed by ivacaftor (CFTR potentiator) in patients with gating (G551D) mutations. CF neutrophils formed more NETs and this was reversed by cyclin-dependent kinase inhibitor exposure. NETs provided a proinflammatory stimulus to macrophages, which was enhanced in CF. CONCLUSIONS: CF neutrophils have a prosurvival phenotype that is associated with an absence of CFTR function and allows increased NET production, which can in turn induce inflammation. Augmenting neutrophil apoptosis in CF may allow more appropriate neutrophil disposal, decreasing NET formation and thus inflammation.


Assuntos
Apoptose/fisiologia , Fibrose Cística/patologia , Armadilhas Extracelulares , Neutrófilos/fisiologia , Adulto , Animais , Estudos de Casos e Controles , Sobrevivência Celular , Fibrose Cística/sangue , Fibrose Cística/imunologia , Humanos , Inflamação , Suínos , Fatores de Tempo
20.
J Antimicrob Chemother ; 73(4): 891-899, 2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29325167

RESUMO

Background: Candida auris has emerged globally as an MDR nosocomial pathogen in ICU patients. Objectives: We studied the antifungal susceptibility of C. auris isolates (n = 350) from 10 hospitals in India collected over a period of 8 years. To investigate azole resistance, ERG11 gene sequencing and expression profiling was conducted. In addition, echinocandin resistance linked to mutations in the C. auris FKS1 gene was analysed. Methods: CLSI antifungal susceptibility testing of six azoles, amphotericin B, three echinocandins, terbinafine, 5-flucytosine and nystatin was conducted. Screening for amino acid substitutions in ERG11 and FKS1 was performed. Results: Overall, 90% of C. auris were fluconazole resistant (MICs 32 to ≥64 mg/L) and 2% and 8% were resistant to echinocandins (≥8 mg/L) and amphotericin B (≥2 mg/L), respectively. ERG11 sequences of C. auris exhibited amino acid substitutions Y132 and K143 in 77% (n = 34/44) of strains that were fluconazole resistant whereas WT genotypes, i.e. without substitutions at these positions, were observed in isolates with low fluconazole MICs (1-2 mg/L) suggesting that these substitutions confer a phenotype of resistance to fluconazole similar to that described for Candida albicans. No significant expression of ERG11 was observed, although expression was inducible in vitro with fluconazole exposure. Echinocandin resistance was linked to a novel mutation S639F in FKS1 hot spot region I. Conclusions: Overall, 25% and 13% of isolates were MDR and multi-azole resistant, respectively. The most common resistance combination was azoles and 5-flucytosine in 14% followed by azoles and amphotericin B in 7% and azoles and echinocandins in 2% of isolates.


Assuntos
Antifúngicos/farmacologia , Azóis/farmacologia , Candida/efeitos dos fármacos , Candidíase/microbiologia , Farmacorresistência Fúngica , Equinocandinas/farmacologia , Proteínas Fúngicas/genética , Candida/genética , Candida/isolamento & purificação , Feminino , Perfilação da Expressão Gênica , Genótipo , Humanos , Índia , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Mutação , Análise de Sequência de DNA
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA