Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 86
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Malar J ; 23(1): 82, 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38500094

RESUMO

BACKGROUND: Adults infected with Plasmodium spp. in endemic areas need to be re-evaluated in light of global malaria elimination goals. They potentially undermine malaria interventions but remain an overlooked aspect of public health strategies. METHODS: This study aimed to estimate the prevalence of Plasmodium spp. infections, to identify underlying parasite species, and to assess predicting factors among adults residing in an endemic area from the Democratic Republic of Congo (DRC). A community-based cross-sectional survey in subjects aged 18 years and above was therefore carried out. Study participants were interviewed using a standard questionnaire and tested for Plasmodium spp. using a rapid diagnostic test and a nested polymerase chain reaction assay. Logistic regression models were fitted to assess the effect of potential predictive factors for infections with different Plasmodium spp. RESULTS: Overall, 420 adults with an estimated prevalence of Plasmodium spp. infections of 60.2% [95% CI 55.5; 64.8] were included. Non-falciparum species infected 26.2% [95% CI 22.2; 30.5] of the study population. Among infected participants, three parasite species were identified, including Plasmodium falciparum (88.5%), Plasmodium malariae (39.9%), and Plasmodium ovale (7.5%) but no Plasmodium vivax. Mixed species accounted for 42.3% of infections while single-species infections predominated with P. falciparum (56.5%) among infected participants. All infected participants were asymptomatic at the time of the survey. Adults belonging to the "most economically disadvantaged" households had increased risks of infections with any Plasmodium spp. (adjusted odds ratio, aOR = 2.87 [95% CI 1.66, 20.07]; p < 0.001), compared to those from the "less economically disadvantaged" households. Conversely, each 1 year increase in age reduced the risk of infections with any Plasmodium spp. (aOR = 0.99 [95% CI 0.97, 0.99]; p = 0.048). Specifically for non-falciparum spp., males had increased risks of infection than females (aOR = 1.83 [95% CI 1.13, 2.96]; p = 0.014). CONCLUSION: Adults infected with malaria constitute a potentially important latent reservoir for the transmission of the disease in the study setting. They should specifically be taken into account in public health measures and translational research.


Assuntos
Malária Falciparum , Malária , Masculino , Adulto , Feminino , Humanos , República Democrática do Congo/epidemiologia , Estudos Transversais , Malária/epidemiologia , Malária/parasitologia , Malária Falciparum/epidemiologia , Plasmodium falciparum , Plasmodium malariae , Prevalência
2.
J Infect Dis ; 227(6): 780-787, 2023 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-36546706

RESUMO

BACKGROUND: Cross-neutralizing capacity of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants is important in mitigating (re-)exposures. Role of antibody maturation, the process whereby selection of higher affinity antibodies augments host immunity, to determine SARS-CoV-2 neutralizing capacity was investigated. METHODS: Sera from SARS-CoV-2 convalescents at 2, 6, or 10 months postrecovery, and BNT162b2 vaccine recipients at 3 or 25 weeks postvaccination, were analyzed. Anti-spike IgG avidity was measured in urea-treated ELISAs. Neutralizing capacity was assessed by surrogate neutralization assays. Fold change between variant and wild-type neutralization inferred the breadth of neutralizing capacity. RESULTS: Compared with early-convalescent, avidity indices of late-convalescent sera were significantly higher (median, 37.7 [interquartile range 28.4-45.1] vs 64.9 [57.5-71.5], P < .0001). Urea-resistant, high-avidity IgG best predicted neutralizing capacity (Spearman r = 0.49 vs 0.67 [wild-type]; 0.18-0.52 vs 0.48-0.83 [variants]). Higher-avidity convalescent sera better cross-neutralized SARS-CoV-2 variants (P < .001 [Alpha]; P < .01 [Delta and Omicron]). Vaccinees only experienced meaningful avidity maturation following the booster dose, exhibiting rather limited cross-neutralizing capacity at week 25. CONCLUSIONS: Avidity maturation was progressive beyond acute recovery from infection, or became apparent after the booster vaccine dose, granting broader anti-SARS-CoV-2 neutralizing capacity. Understanding the maturation kinetics of the 2 building blocks of anti-SARS-CoV-2 humoral immunity is crucial.


Assuntos
Vacina BNT162 , COVID-19 , Humanos , Afinidade de Anticorpos , Soroterapia para COVID-19 , SARS-CoV-2 , Ureia , Vacinação , Imunoglobulina G , Anticorpos Neutralizantes , Anticorpos Antivirais , Glicoproteína da Espícula de Coronavírus
3.
J Infect Chemother ; 29(1): 112-114, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36167304

RESUMO

Vaccines having aided in escaping the majority of the population from immunological naïvety, our strategies are now shifting towards an increased focus on identifying and protecting the extremely vulnerable. We here describe the results of testing 12 patients, those with lymphoid malignancies having been targeted their B-cells for therapy with rituximab-containing regimens or a Bruton tyrosine kinase inhibitor, for anti-SARS-CoV-2 spike antibodies after receiving the BNT162b2 mRNA vaccine doses. The interval from last dosing of B-cell depletion therapy to SARS-CoV-2 vaccination was at median 5.3 (range 3.1-6.6) months. Using the 'seroprotection' threshold of 775 [BAU/mL] for the anti-spike antibody titer, our finding points out the crucial unresponsiveness of the targeted population with 0/12 (0%) achieving 'seroprotection'. Although IgG seroconversion was observed in 4/12 (33%), supporting the overall benefit of vaccination, the figures still point out a potential need for optimization of practice. IgA was further less responsive (unsuccessful 'seroconversion' in 11/12 (92%)), implicating an underlying class switch defect. Those with depletion on B-cells are caught at a dilemma between, being too early and too late on receiving SARS-CoV-2 vaccines. They wish to get over their immunological naïvety at the earliest, while, in order to assure quality immune memory, are also required to hold the patience for their B-cells to repopulate. Although it remains an issue whether intensified vaccine schedules and/or regimens will lead to stronger immunogenicity or more effective boosters for non-responders, we shall take advantage of every increasing evidence in order to optimize current options.


Assuntos
COVID-19 , Neoplasias , Vacinas Virais , Humanos , Formação de Anticorpos , Vacinas contra COVID-19 , Vacina BNT162 , Switching de Imunoglobulina , Vacinas Virais/farmacologia , COVID-19/prevenção & controle , SARS-CoV-2 , Vacinação , Anticorpos Antivirais , Vacinas de mRNA
4.
J Infect Chemother ; 29(2): 223-227, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36379403

RESUMO

Coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) is being increasingly recognized as a severe complication that contributes to poor prognoses among patients with COVID-19. However, little is known regarding the clinical course of CAPA with hematological malignancies, especially after allogeneic hematopoietic stem cell transplantation (HSCT). A 29-year-old woman was diagnosed with proven CAPA with an Aspergillus fumigatus identified by cultures of bronchoalveolar lavage and lung biopsy four years after haploidentical HSCT for acute myelogenous leukemia. She had been taking oral prednisolone for bronchiolitis obliterans syndrome that developed after HSCT. Although prolonged RT-PCR positivity for SARS-CoV-2 (133 days after the onset of COVID-19) without shedding of viable virus was observed, the COVID-19 was treated with favipiravir, remdesivir, dexamethasone, and enoxaparin. However, the CAPA did not respond to combination therapy, which included triazole (voriconazole, itraconazole, posaconazole) and echinocandin (caspofungin, micafungin), even though the Aspergillus fumigatus isolate was found to be susceptible to these agents in vitro. Nevertheless, a total of 16 weeks of liposomal amphotericin B (L-AMB) therapy led to a favorable response, and the patient was discharged from the hospital on day 213. This case provided essential experience of CAPA treated with L-AMB in a recipient with chronic respiratory disease after HSCT.


Assuntos
Síndrome de Bronquiolite Obliterante , COVID-19 , Transplante de Células-Tronco Hematopoéticas , Aspergilose Pulmonar , Feminino , Humanos , Adulto , Antifúngicos/uso terapêutico , COVID-19/complicações , SARS-CoV-2 , Aspergilose Pulmonar/complicações , Aspergilose Pulmonar/tratamento farmacológico , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Aspergillus fumigatus
5.
Parasitol Res ; 122(8): 1795-1800, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37264281

RESUMO

Eimeria spp. are protozoan parasites that are commonly found in a broad range of vertebrate hosts. These parasites generally exhibit strict host specificity, but some Eimeria spp. can infect groups of closely related species such as species within a genus or family. Compared with Eimeria spp. that infect livestock, limited information is available about such infections in wild animals including data on host specificity, virulence, and prevalence. The Japanese rock ptarmigan, Lagopus muta japonica, is an endangered bird belonging to the family Phasianidae, order Galliformes, and inhabits only alpine areas of Japan. In conservation efforts for these birds, two Eimeria spp., E. uekii and E. raichoi, were frequently detected. Here, we examined cross-transmission of the parasites to other bird species to characterize their infectivity as well as the development of experimental bird models to contribute to conservation programs by the oocyst transfer. Consequently, among the examined eight bird species (chickens, Japanese pheasants, turkeys, chukar partridges, quails, helmeted guineafowls and ducks), only turkeys (family Phasianidae, order Galliformes) could be infected with E. raichoi. However, the number of oocysts per feces was relatively low, and few parasites in the intestinal mucosa could be found by histopathological analyses. These results might indicate that E. uekii and E. raichoi are highly adapted to Japanese rock ptarmigans that inhabit the alpine zone although further studies are anticipated.


Assuntos
Animais Selvagens , Coccidiose , Eimeria , Espécies em Perigo de Extinção , Galliformes , Especificidade de Hospedeiro , Animais , Galinhas/parasitologia , Coccidiose/veterinária , Coccidiose/parasitologia , Galliformes/parasitologia , Oocistos , Codorniz/parasitologia , Japão , Fezes/parasitologia , Animais Selvagens/parasitologia , Patos/parasitologia
6.
J Clin Immunol ; 42(7): 1360-1370, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35764767

RESUMO

PURPOSE: Autoantibodies (aAbs) to type I interferons (IFNs) have been found in less than 1% of individuals under the age of 60 in the general population, with the prevalence increasing among those over 65. Neutralizing autoantibodies (naAbs) to type I IFNs have been found in at least 15% of patients with life-threatening COVID-19 pneumonia in several cohorts of primarily European descent. We aimed to evaluate the prevalence of aAbs and naAbs to IFN-α2 or IFN-ω in Japanese patients who suffered from COVID-19 as well as in the general population. METHODS: Patients who suffered from COVID-19 (n = 622, aged 0-104) and an uninfected healthy control population (n = 3,456, aged 20-91) were enrolled in this study. The severities of the COVID-19 patients were as follows: critical (n = 170), severe (n = 235), moderate (n = 112), and mild (n = 105). ELISA and ISRE reporter assays were used to detect aAbs and naAbs to IFN-α2 and IFN-ω using E. coli-produced IFNs. RESULTS: In an uninfected general Japanese population aged 20-91, aAbs to IFNs were detected in 0.087% of individuals. By contrast, naAbs to type I IFNs (IFN-α2 and/or IFN-ω, 100 pg/mL) were detected in 10.6% of patients with critical infections, 2.6% of patients with severe infections, and 1% of patients with mild infections. The presence of naAbs to IFNs was significantly associated with critical disease (P = 0.0012), age over 50 (P = 0.0002), and male sex (P = 0.137). A significant but not strong correlation between aAbs and naAbs to IFN-α2 existed (r = - 0.307, p value < 0.0001) reinforced the importance of measuring naAbs in COVID-19 patients, including those of Japanese ancestry. CONCLUSION: In this study, we revealed that patients with pre-existing naAbs have a much higher risk of life-threatening COVID-19 pneumonia in Japanese population.


Assuntos
COVID-19 , Interferon Tipo I , Humanos , Masculino , COVID-19/epidemiologia , Autoanticorpos , Escherichia coli , Japão/epidemiologia
7.
BMC Med ; 20(1): 342, 2022 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-36163020

RESUMO

BACKGROUND: In vitro drug screening studies have indicated that camostat mesilate (FOY-305) may prevent SARS-CoV-2 infection into human airway epithelial cells. This study was conducted to investigate whether camostat mesilate is an effective treatment for SARS-CoV-2 infection (COVID-19). METHODS: This was a multicenter, double-blind, randomized, parallel-group, placebo-controlled study. Patients were enrolled if they were admitted to a hospital within 5 days of onset of COVID-19 symptoms or within 5 days of a positive test for asymptomatic patients. Severe cases (e.g., those requiring oxygenation/ventilation) were excluded. Patients were enrolled, randomized, and allocated to each group using an interactive web response system. Randomization was performed using a minimization method with the factors medical institution, age, and underlying diseases (chronic respiratory disease, chronic kidney disease, diabetes mellitus, hypertension, cardiovascular diseases, and obesity). The patients, investigators/subinvestigators, study coordinators, and other study personnel were blinded throughout the study. Patients were administered camostat mesilate (600 mg qid; four to eight times higher than the clinical doses in Japan) or placebo for up to 14 days. The primary efficacy endpoint was the time to the first two consecutive negative tests for SARS-CoV-2. RESULTS: One-hundred fifty-five patients were randomized to receive camostat mesilate (n = 78) or placebo (n = 77). The median time to the first test was 11.0 days (95% confidence interval [CI]: 9.0-12.0) in the camostat mesilate group and 11.0 days (95% CI: 10.0-13.0) in the placebo group. Conversion to negative viral status by day 14 was observed in 45 of 74 patients (60.8%) in the camostat mesilate group and 47 of 74 patients (63.5%) in the placebo group. The primary (Bayesian) and secondary (frequentist) analyses found no significant differences in the primary endpoint between the two groups. No additional safety concerns beyond those already known for camostat mesilate were identified. CONCLUSIONS: Camostat mesilate did not substantially reduce the time to viral clearance, based on upper airway viral loads, compared with placebo for treating patients with mild to moderate SARS-CoV-2 infection with or without symptoms. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04657497. Japan Registry for Clinical Trials, jRCT2031200198.


Assuntos
Tratamento Farmacológico da COVID-19 , Teorema de Bayes , Método Duplo-Cego , Ésteres/efeitos adversos , Ésteres/uso terapêutico , Guanidinas/efeitos adversos , Guanidinas/uso terapêutico , Humanos , SARS-CoV-2 , Resultado do Tratamento
8.
Proc Natl Acad Sci U S A ; 116(17): 8269-8274, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-30952781

RESUMO

Ascofuranone (AF) and ascochlorin (AC) are meroterpenoids produced by various filamentous fungi, including Acremonium egyptiacum (synonym: Acremonium sclerotigenum), and exhibit diverse physiological activities. In particular, AF is a promising drug candidate against African trypanosomiasis and a potential anticancer lead compound. These compounds are supposedly biosynthesized through farnesylation of orsellinic acid, but the details have not been established. In this study, we present all of the reactions and responsible genes for AF and AC biosyntheses in A. egyptiacum, identified by heterologous expression, in vitro reconstruction, and gene deletion experiments with the aid of a genome-wide differential expression analysis. Both pathways share the common precursor, ilicicolin A epoxide, which is processed by the membrane-bound terpene cyclase (TPC) AscF in AC biosynthesis. AF biosynthesis branches from the precursor by hydroxylation at C-16 by the P450 monooxygenase AscH, followed by cyclization by a membrane-bound TPC AscI. All genes required for AC biosynthesis (ascABCDEFG) and a transcriptional factor (ascR) form a functional gene cluster, whereas those involved in the late steps of AF biosynthesis (ascHIJ) are present in another distantly located cluster. AF is therefore a rare example of fungal secondary metabolites requiring multilocus biosynthetic clusters, which are likely to be controlled by the single regulator, AscR. Finally, we achieved the selective production of AF in A. egyptiacum by genetically blocking the AC biosynthetic pathway; further manipulation of the strain will lead to the cost-effective mass production required for the clinical use of AF.


Assuntos
Acremonium , Alcenos , Fenóis , Sesquiterpenos , Acremonium/enzimologia , Acremonium/genética , Acremonium/metabolismo , Alcenos/química , Alcenos/metabolismo , Vias Biossintéticas/fisiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Genes Fúngicos/genética , Modelos Moleculares , Família Multigênica/genética , Fenóis/química , Fenóis/metabolismo , Sesquiterpenos/química , Sesquiterpenos/metabolismo
9.
Rinsho Ketsueki ; 63(10): 1379-1385, 2022.
Artigo em Japonês | MEDLINE | ID: mdl-36351643

RESUMO

There is currently no evidence that a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine might be associated with the development of autoimmune hemolytic anemia or disease progression in patients with mature B-cell neoplasm. Our patient was a 71-year-old man with indolent mature B-cell neoplasm who had been monitored for many years without treatment. After receiving the second dose of the BNT162b2 mRNA COVID-19 vaccine, he developed severe warm autoimmune hemolytic anemia. Although steroid therapy improved his anemia, he continued to develop IgM-monoclonal gammopathy, renal insufficiency, and splenomegaly. He was diagnosed with splenic marginal zone lymphoma after undergoing splenectomy. The splenectomy improved the patient's symptoms. We assessed his SARS-CoV-2 specific antibody response, but the patient's serologic response to the vaccine was impaired. In patients with mature B-cell neoplasm, a non-specific immune response after vaccination might be associated with paraneoplastic syndromes.


Assuntos
Anemia Hemolítica Autoimune , Vacinas contra COVID-19 , COVID-19 , Leucemia Linfocítica Crônica de Células B , Linfoma de Células B , Paraproteinemias , Neoplasias Esplênicas , Idoso , Humanos , Masculino , Anemia Hemolítica Autoimune/etiologia , Anemia Hemolítica Autoimune/complicações , Vacina BNT162 , COVID-19/complicações , Vacinas contra COVID-19/efeitos adversos , Imunoglobulina M , Leucemia Linfocítica Crônica de Células B/complicações , Linfoma de Células B/tratamento farmacológico , Paraproteinemias/complicações , SARS-CoV-2 , Neoplasias Esplênicas/complicações , Vacinas de mRNA
10.
J Infect Dis ; 223(4): 610-620, 2021 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-33057717

RESUMO

BACKGROUND: USA300 produces Panton-Valentin leucocidin (PVL) and is known as a predominant community-associated methicillin-resistant Staphylococcus aureus (MRSA) strain in the United States, but it was extremely rare in Japan. We report here an outbreak of USA300 in people with HIV (PWH) in Tokyo, Japan. METHODS: We analyzed the cases of PVL-MRSA infection between 2010 and 2020 and screened for nasal colonization of PVL-MRSA in PWH who visited an HIV/AIDS referral hospital from December 2019 to March 2020. Whole-genome sequencing-based single nucleotide polymorphism (SNP) analysis was performed on these isolates. RESULTS: During the study period, a total of 21 PVL-MRSA infections in 14 patients were identified after 2014. The carriage prevalence was 4.3% (12/277) and PVL-MRSA carriers were more likely to have sexually transmitted infections (STIs) within a year compared with patients who had neither a history of PVL-MRSA infection nor colonization (33.3% [4/12] vs 10.1% [26/258]; P = .03). SNP analysis showed that all 26 isolates were ST8-SCCmecIVa-USA300. Twenty-four isolates were closely related (≤100 SNP differences) and had the nonsynonymous SNPs associated with carbohydrate metabolism and antimicrobial tolerance. CONCLUSIONS: An outbreak of USA300 has been occurring among PWH in Tokyo and a history of STI was a risk of colonization.


Assuntos
Surtos de Doenças , Infecções por HIV/complicações , Homossexualidade Masculina , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Infecções Estafilocócicas/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , Portador Sadio , Farmacorresistência Bacteriana Múltipla , Genoma Bacteriano , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Pessoa de Meia-Idade , Tipagem Molecular , Nariz/microbiologia , Filogenia , Polimorfismo de Nucleotídeo Único , Prevalência , Estudos Retrospectivos , Infecções Sexualmente Transmissíveis/complicações , Infecções Estafilocócicas/complicações , Tóquio/epidemiologia , Fatores de Virulência/análise , Sequenciamento Completo do Genoma , Adulto Jovem
11.
Emerg Infect Dis ; 27(2): 628-631, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33496235

RESUMO

We used 2 commercially available antibody tests to estimate seroprevalence of severe acute respiratory syndrome coronavirus 2 infection in Japan during June 2020. Of 7,950 samples, 8 were positive by both assays. Using 2 reliable antibody tests in conjunction is an effective method for estimating seroprevalence in low prevalence settings.


Assuntos
Anticorpos Antivirais/sangue , Teste Sorológico para COVID-19/estatística & dados numéricos , COVID-19/epidemiologia , SARS-CoV-2/imunologia , Adulto , Idoso , COVID-19/sangue , COVID-19/imunologia , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Soroepidemiológicos , Adulto Jovem
12.
J Med Virol ; 93(7): 4549-4552, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33739483

RESUMO

BACKGROUND: The gold standard for coronavirus disease (COVID-19) diagnosis has been the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA by nucleic acid amplification testing (NAAT). On the other hand, serological testing for COVID-19 may offer advantages in detecting possibly overlooked infections by NAAT. METHODS: To evaluate seroconversion of NAAT-negative pneumonia patients, immunoglobulin M (IgM) and IgG targeting the spike protein of SARS-CoV-2 were semiquantified by an immunofluorescence assay. Seroconversion was confirmed by another serological method, targeting the nucleocapsid protein. RESULTS: Eight suspected but unconfirmed COVID-19 pneumonia patients (median age, 39 years; range, 21-55) were included. The median period between symptom onset and NAAT sample collection was 6 days (2-27 days). None of them had tested positive for SARS-CoV-2 by NAAT. In contrast, all eight patients revealed seropositivity with the two serological methods, indicating actual seroconversion against SARS-CoV-2. The median period between onset and blood sampling was 26.5 days (7-51 days). CONCLUSION: Eight patients with COVID-19 pneumonia, initially tested negative for SARS-CoV-2 by NAAT, were finally confirmed of the diagnosis by serological testing. To cover the whole spectrum of this heterogenous infectious disease, serology testing should be implemented to the multitiered diagnostic algorithm for COVID-19.


Assuntos
Anticorpos Antivirais/sangue , Teste Sorológico para COVID-19/métodos , COVID-19/diagnóstico , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Adulto , Proteínas do Nucleocapsídeo de Coronavírus/imunologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fosfoproteínas/imunologia , SARS-CoV-2/imunologia , Soroconversão , Glicoproteína da Espícula de Coronavírus/imunologia , Adulto Jovem
13.
Int J Mol Sci ; 22(15)2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34360597

RESUMO

Toxoplasma gondii is a protozoan parasite that causes toxoplasmosis and infects almost one-third of the global human population. A lack of effective drugs and vaccines and the emergence of drug resistant parasites highlight the need for the development of new drugs. The mitochondrial electron transport chain (ETC) is an essential pathway for energy metabolism and the survival of T. gondii. In apicomplexan parasites, malate:quinone oxidoreductase (MQO) is a monotopic membrane protein belonging to the ETC and a key member of the tricarboxylic acid cycle, and has recently been suggested to play a role in the fumarate cycle, which is required for the cytosolic purine salvage pathway. In T. gondii, a putative MQO (TgMQO) is expressed in tachyzoite and bradyzoite stages and is considered to be a potential drug target since its orthologue is not conserved in mammalian hosts. As a first step towards the evaluation of TgMQO as a drug target candidate, in this study, we developed a new expression system for TgMQO in FN102(DE3)TAO, a strain deficient in respiratory cytochromes and dependent on an alternative oxidase. This system allowed, for the first time, the expression and purification of a mitochondrial MQO family enzyme, which was used for steady-state kinetics and substrate specificity analyses. Ferulenol, the only known MQO inhibitor, also inhibited TgMQO at IC50 of 0.822 µM, and displayed different inhibition kinetics compared to Plasmodium falciparum MQO. Furthermore, our analysis indicated the presence of a third binding site for ferulenol that is distinct from the ubiquinone and malate sites.


Assuntos
Cumarínicos/metabolismo , Malatos/metabolismo , Proteínas Mitocondriais/metabolismo , Oxirredutases/metabolismo , Proteínas de Protozoários/metabolismo , Toxoplasma/enzimologia , Ubiquinona/metabolismo , Animais , Humanos , Proteínas Mitocondriais/genética , Oxirredutases/genética , Proteínas de Protozoários/genética , Especificidade por Substrato
14.
FASEB J ; 33(11): 13002-13013, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31525300

RESUMO

African trypanosomiasis, sleeping sickness in humans or nagana in animals, is a potentially fatal neglected tropical disease and a threat to 65 million human lives and 100 million small and large livestock animals in sub-Saharan Africa. Available treatments for this devastating disease are few and have limited efficacy, prompting the search for new drug candidates. Simultaneous inhibition of the trypanosomal glycerol kinase (TGK) and trypanosomal alternative oxidase (TAO) is considered a validated strategy toward the development of new drugs. Our goal is to develop a TGK-specific inhibitor for coadministration with ascofuranone (AF), the most potent TAO inhibitor. Here, we report on the identification of novel compounds with inhibitory potency against TGK. Importantly, one of these compounds (compound 17) and its derivatives (17a and 17b) killed trypanosomes even in the absence of AF. Inhibition kinetics revealed that derivative 17b is a mixed-type and competitive inhibitor for TGK and TAO, respectively. Structural data revealed the molecular basis of this dual inhibitory action, which, in our opinion, will aid in the successful development of a promising drug to treat trypanosomiasis. Although the EC50 of compound 17b against trypanosome cells was 1.77 µM, it had no effect on cultured human cells, even at 50 µM.-Balogun, E. O., Inaoka, D. K., Shiba, T., Tsuge, C., May, B., Sato, T., Kido, Y., Nara, T., Aoki, T., Honma, T., Tanaka, A., Inoue, M., Matsuoka, S., Michels, P. A. M., Watanabe, Y.-I., Moore, A. L., Harada, S., Kita, K. Discovery of trypanocidal coumarins with dual inhibition of both the glycerol kinase and alternative oxidase of Trypanosoma brucei brucei.


Assuntos
Cumarínicos/farmacologia , Descoberta de Drogas , Glicerol Quinase/antagonistas & inibidores , Proteínas Mitocondriais/antagonistas & inibidores , Oxirredutases/antagonistas & inibidores , Proteínas de Plantas/antagonistas & inibidores , Tripanossomicidas/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos , Animais , Cumarínicos/química , Glicerol Quinase/metabolismo , Proteínas Mitocondriais/metabolismo , Oxirredutases/metabolismo , Proteínas de Plantas/metabolismo , Trypanosoma brucei brucei/enzimologia
15.
Med Microbiol Immunol ; 209(1): 29-40, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31549252

RESUMO

Currently, Western-type CagA is used in most commercial Helicobacter pylori CagA ELISA kits for CagA detection rather than East Asian-type CagA. We evaluated the ability of the East Asian-type CagA ELISA developed by our group to detect anti-CagA antibody in patients infected with different cagA genotypes of H. pylori from four different countries in South Asia and Southeast Asia. The recombinant CagA protein was expressed and later purified using GST-tag affinity chromatography. The East Asian-type CagA-immobilized ELISA was used to measure the levels of anti-CagA antibody in 750 serum samples from Bhutan, Indonesia, Myanmar, and Bangladesh. The cutoff value of the serum antibody in each country was determined via Receiver-Operating Characteristic (ROC) analysis. The cutoff values were different among the four countries studied (Bhutan, 18.16 U/mL; Indonesia, 6.01 U/mL; Myanmar, 10.57 U/mL; and Bangladesh, 6.19 U/mL). Our ELISA had better sensitivity, specificity, and accuracy of anti-CagA antibody detection in subjects predominantly infected with East Asian-type CagA H. pylori (Bhutan and Indonesia) than in those infected with Western-type CagA H. pylori predominant (Myanmar and Bangladesh). We found positive correlations between the anti-CagA antibody and antral monocyte infiltration in subjects from all four countries. There was no significant association between bacterial density and the anti-CagA antibody in the antrum or the corpus. The East Asian-type CagA ELISA had improved detection of the anti-CagA antibody in subjects infected with East Asian-type CagA H. pylori. The East Asian-type CagA ELISA should, therefore, be used in populations predominantly infected with East Asian-type CagA.


Assuntos
Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , Genótipo , Infecções por Helicobacter/diagnóstico , Infecções por Helicobacter/microbiologia , Helicobacter pylori/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos de Bactérias/imunologia , Proteínas de Bactérias/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Infecções por Helicobacter/imunologia , Helicobacter pylori/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Curva ROC , Adulto Jovem
16.
J Pharmacol Sci ; 141(1): 56-63, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31611176

RESUMO

Concomitant heart failure is associated with poor clinical outcome in dialysis patients. The arteriovenous shunt, created as vascular access for hemodialysis, increases ventricular volume-overload, predisposing patients to developing cardiac dysfunction. The integral function of mitochondrial respiration is critically important for the heart to cope with hemodynamic overload. The involvement, however, of mitochondrial activity or reactive oxygen species (ROS) in the pathogenesis of ventricular-overload-induced heart failure has not been fully elucidated. We herein report that disorganization of mitochondrial respiration increases mitochondrial ROS production in the volume-overloaded heart, leading to ventricular dysfunction. We adopted the murine arteriovenous fistula (AVF) model, which replicates the cardinal features of volume-overload-induced ventricular dysfunction. Enzymatic assays of cardiac mitochondria revealed that the activities of citrate synthase and NADH-quinone reductase (complex Ⅰ) were preserved in the AVF heart. In contrast, the activity of NADH oxidase supercomplex was significantly compromised, resulting in elevated ROS production. Importantly, the antioxidant N-acetylcysteine prevented the development of ventricular dilatation and cardiac dysfunction, suggesting a pathogenic role for ROS in dialysis-related cardiomyopathy. A cardioprotective effect was also observed in metformin-treated mice, illuminating its potential use in the management of heart failure complicating diabetic patients on dialysis.


Assuntos
Acetilcisteína/uso terapêutico , Antioxidantes/uso terapêutico , Cardiomiopatias/tratamento farmacológico , Cardiomiopatias/etiologia , Mitocôndrias/metabolismo , Terapia de Alvo Molecular , Miócitos Cardíacos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Acetilcisteína/farmacologia , Animais , Antioxidantes/farmacologia , Cardiomiopatias/metabolismo , Modelos Animais de Doenças , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/prevenção & controle , Masculino , Camundongos Endogâmicos C57BL
17.
Int J Mol Sci ; 19(10)2018 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-30301191

RESUMO

Hepatic stellate cells (HSCs) are key players in liver fibrosis, cellular senescence, and hepatic carcinogenesis. Bile acids (BAs) are involved in the activation of HSCs, but the detailed mechanism of this process remains unclear. We conducted a comprehensive DNA microarray study of the human HSC line LX-2 treated with deoxycholic acid (DCA), a secondary unconjugated BA. Additionally, LX-2 cells were exposed to nine BAs and studied using immunofluorescence staining, enzyme-linked immunosorbent assay, and flow cytometry to examine the mechanisms of HSC activation. We focused on the tumor necrosis factor (TNF) pathway and revealed upregulation of genes related to nuclear factor kappa B (NF-κB) signaling and senescence-associated secretory phenotype factors. α-Smooth muscle actin (α-SMA) was highly expressed in cells treated with secondary unconjugated BAs, including DCA, and a morphological change associated with radial extension of subendothelial protrusion was observed. Interleukin-6 level in culture supernatant was significantly higher in cells treated with secondary unconjugated BAs. Flow cytometry showed that the proportion of cells highly expressing α-SMA was significantly increased in HSCs cultured with secondary unconjugated BAs. We demonstrated that secondary unconjugated BAs induced the activation of human HSCs.


Assuntos
Ácidos e Sais Biliares/metabolismo , Células Estreladas do Fígado/metabolismo , Actinas/genética , Actinas/metabolismo , Ácidos e Sais Biliares/farmacologia , Linhagem Celular , Ácido Desoxicólico/farmacologia , Perfilação da Expressão Gênica , Células Estreladas do Fígado/efeitos dos fármacos , Humanos , Interleucina-6/análise , NF-kappa B/genética , NF-kappa B/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo
20.
Biochim Biophys Acta Gen Subj ; 1861(11 Pt A): 2830-2842, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28778484

RESUMO

BACKGROUND: In general, glycerol kinases (GKs) are transferases that catalyze phospho group transfer from ATP to glycerol, and the mechanism was suggested to be random bi-bi. The reverse reaction i.e. phospho transfer from glycerol 3-phosphate (G3P) to ADP is only physiologically feasible by the African trypanosome GK. In contrast to other GKs the mechanism of Trypanosoma brucei gambiense glycerol kinase (TbgGK) was shown to be in an ordered fashion, and proceeding via autophosphorylation. From the unique reaction mechanism of TbgGK, we envisaged its potential to possess phosphatase activity in addition to being a kinase. METHODS: Our hypothesis was tested by spectrophotometric and LC-MS/MS analyses using paranitrophenyl phosphate (pNPP) and TbgGK's natural substrate, G3P respectively. Furthermore, protein X-ray crystallography and site-directed mutagenesis were performed to examine pNPP binding, catalytic residues, and the possible reaction mechanism. RESULTS: In addition to its widely known and expected phosphotransferase (class II) activity, TbgGK can efficiently facilitate the hydrolytic cleavage of phosphoric anhydride bonds (a class III property). This phosphatase activity followed the classical Michaelis-Menten pattern and was competitively inhibited by ADP and G3P, suggesting a common catalytic site for both activities (phosphatase and kinase). The structure of the TGK-pNPP complex, and structure-guided mutagenesis implicated T276 to be important for the catalysis. Remarkably, we captured a crystallographic molecular snapshot of the phosphorylated T276 reaction intermediate. CONCLUSION: We conclude that TbgGK has both kinase and phosphatase activities. GENERAL SIGNIFICANCE: This is the first report on a bifunctional kinase/phosphatase enzyme among members of the sugar kinase family.


Assuntos
Glicerol Quinase/química , Monoéster Fosfórico Hidrolases/química , Conformação Proteica , Trypanosoma brucei gambiense/enzimologia , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Cristalografia por Raios X , Glicerol/metabolismo , Glicerol Quinase/genética , Glicerol Quinase/metabolismo , Glicerofosfatos/metabolismo , Humanos , Nitrobenzenos/química , Monoéster Fosfórico Hidrolases/metabolismo , Especificidade por Substrato , Trypanosoma brucei gambiense/patogenicidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA