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1.
J Geriatr Oncol ; 15(4): 101761, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38581958

RESUMO

INTRODUCTION: Current hospital-based care pathways are generally single-disease centred. As a result, coexisting morbidities are often suboptimally evaluated and managed, a deficiency becoming increasingly apparent among older patients who exhibit heterogeneity in health status, functional abilities, frailty, and other geriatric impairments. To address this issue, our study aims to assess a newly developed patient-centred care pathway for older patients with multimorbidity and cancer. The new care pathway was based on currently available evidence and co-designed by end-users including health care professionals, patients, and informal caregivers. Within this care pathway, all healthcare professionals involved in the care of older patients with multimorbidity and cancer will form a Health Professional Consortium (HPC). The role of the HPC will be to centralise oncologic and non-oncologic treatment recommendations in accordance with the patient's priorities. Moreover, an Advanced Practice Nurse will act as case-manager by being the primary point of contact for the patient, thus improving coordination between specialists, and by organising and leading the consortium. Patient monitoring and the HPC collaboration will be facilitated by digital communication tools designed specifically for this purpose, with the added benefit of being customisable for each patient. MATERIALS AND METHODS: The GERONTE study is a prospective international, multicentric study consisting of two stepped-wedge trials performed at 16 clinical sites across three European countries. Each trial will include 720 patients aged 70 years and over with a new or progressive cancer (breast, lung, colorectal, prostate) and at least one moderate or severe multimorbidity. The patients in the intervention group will receive the new care pathway whereas patients in the control group will receive usual oncologic care. DISCUSSION: GERONTE will evaluate whether this kind of holistic, patient-oriented healthcare management can improve quality of life (primary outcome) and other valuable endpoints in older patients with multimorbidity and cancer. An ancillary study will assess in depth the socio-economic impact of the intervention and deliver concrete implementation guidelines for the GERONTE intervention care pathway. TRIAL REGISTRATION: FRONE: NCT05720910 TWOBE: NCT05423808.


Assuntos
Multimorbidade , Neoplasias , Assistência Centrada no Paciente , Humanos , Neoplasias/complicações , Neoplasias/terapia , Idoso , Tecnologia da Informação , Procedimentos Clínicos , Saúde Holística , Idoso de 80 Anos ou mais , Masculino , Feminino
2.
Lancet Glob Health ; 11(11): e1743-e1752, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37858585

RESUMO

BACKGROUND: This study assessed the safety and immunogenicity of the Ad26.ZEBOV and MVA-BN-Filo Ebola virus (EBOV) vaccine regimen in infants aged 4-11 months in Guinea and Sierra Leone. METHODS: In this phase 2, randomised, double-blind, active-controlled trial, we randomly assigned healthy infants (1:1 in a sentinel cohort, 5:2 for the remaining infants via an interactive web response system) to receive Ad26.ZEBOV followed by MVA-BN-Filo (Ebola vaccine group) or two doses of meningococcal quadrivalent conjugate vaccine (control group) administered 56 days apart. Infants were recruited at two sites in west Africa: Conakry, Guinea, and Kambia, Sierra Leone. All infants received the meningococcal vaccine 8 months after being randomly assigned. The primary objective was safety. The secondary objective was immunogenicity, measured as EBOV glycoprotein-binding antibody concentration 21 days post-dose 2, using the Filovirus Animal Non-Clinical Group ELISA. This study is registered with ClinicalTrials.gov (NCT03929757) and the Pan African Clinical Trials Registry (PACTR201905827924069). FINDINGS: From Aug 20 to Nov 29, 2019, 142 infants were screened and 108 were randomly assigned (Ebola vaccine n=75; control n=33). The most common solicited local adverse event was injection-site pain (Ebola vaccine 15 [20%] of 75; control four [12%] of 33). The most common solicited systemic adverse events with the Ebola vaccine were irritability (26 [35%] of 75), decreased appetite (18 [24%] of 75), pyrexia (16 [21%] of 75), and decreased activity (15 [20%] of 75). In the control group, ten (30%) of 33 had irritability, seven (21%) of 33 had decreased appetite, three (9%) of 33 had pyrexia, and five (15%) of 33 had decreased activity. The frequency of unsolicited adverse events was 83% (62 of 75 infants) in the Ebola vaccine group and 85% (28 of 33 infants) in the control group. No serious adverse events were vaccine-related. In the Ebola vaccine group, EBOV glycoprotein-binding antibody geometric mean concentrations (GMCs) at 21 days post-dose 2 were 27 700 ELISA units (EU)/mL (95% CI 20 477-37 470) in infants aged 4-8 months and 20 481 EU/mL (15 325-27 372) in infants aged 9-11 months. The responder rate was 100% (74 of 74 responded). In the control group, GMCs for both age groups were less than the lower limit of quantification and the responder rate was 3% (one of 33 responded). INTERPRETATION: Ad26.ZEBOV and MVA-BN-Filo was well tolerated and induced strong humoral responses in infants younger than 1 year. There were no safety concerns related to vaccination. FUNDING: Janssen Vaccines & Prevention and Innovative Medicines Initiative 2 Joint Undertaking. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.


Assuntos
Vacinas contra Ebola , Ebolavirus , Doença pelo Vírus Ebola , Animais , Humanos , Lactente , Vacinas contra Ebola/efeitos adversos , Doença pelo Vírus Ebola/prevenção & controle , Serra Leoa , Guiné , Anticorpos Antivirais , Método Duplo-Cego , Glicoproteínas , Febre
3.
Clin Infect Dis ; 77(1): 64-73, 2023 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-36883578

RESUMO

BACKGROUND: Randomized controlled trials (RCTs) from low- and middle-income settings suggested that early initiation of antiretroviral therapy (ART) leads to higher mortality rates among people with HIV (PWH) who present with cryptococcal meningitis (CM). There is limited information about the impact of ART timing on mortality rates in similar people in high-income settings. METHODS: Data on ART-naive PWH with CM diagnosed from 1994 to 2012 from Europe/North America were pooled from the COHERE, NA-ACCORD, and CNICS HIV cohort collaborations. Follow-up was considered to span from the date of CM diagnosis to earliest of the following: death, last follow-up, or 6 months. We used marginal structural models to mimic an RCT comparing the effects of early (within 14 days of CM) and late (14-56 days after CM) ART on all-cause mortality, adjusting for potential confounders. RESULTS: Of 190 participants identified, 33 (17%) died within 6 months. At CM diagnosis, their median age (interquartile range) was 38 (33-44) years; the median CD4+ T-cell count, 19/µL (10-56/µL); and median HIV viral load, 5.3 (4.9-5.6) log10 copies/mL. Most participants (n = 157 [83%]) were male, and 145 (76%) started ART. Mimicking an RCT, with 190 people in each group, there were 13 deaths among participants with an early ART regimen and 20 deaths among those with a late ART regimen. The crude and adjusted hazard ratios comparing late with early ART were 1.28 (95% confidence interval, .64-2.56) and 1.40 (.66-2.95), respectively. CONCLUSIONS: We found little evidence that early ART was associated with higher mortality rates among PWH presenting with CM in high-income settings, although confidence intervals were wide.


Assuntos
Infecções por HIV , Meningite Criptocócica , Masculino , Humanos , Adulto , Feminino , Meningite Criptocócica/complicações , HIV , Países Desenvolvidos , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Antirretrovirais/uso terapêutico , Estudos de Coortes , Contagem de Linfócito CD4
4.
Pharmacogenomics J ; 23(1): 14-20, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36266537

RESUMO

Using concentration-time data from the NEAT001/ARNS143 study (single sample at week 4 and 24), we determined raltegravir pharmacokinetic parameters using nonlinear mixed effects modelling (NONMEM v.7.3; 602 samples from 349 patients) and investigated the influence of demographics and SNPs (SLC22A6 and UGT1A1) on raltegravir pharmacokinetics and pharmacodynamics. Demographics and SNPs did not influence raltegravir pharmacokinetics and no significant pharmacokinetic/pharmacodynamic relationships were observed. At week 96, UGT1A1*28/*28 was associated with lower virological failure (p = 0.012), even after adjusting for baseline CD4 count (p = 0.048), but not when adjusted for baseline HIV-1 viral load (p = 0.082) or both (p = 0.089). This is the first study to our knowledge to assess the influence of SNPs on raltegravir pharmacodynamics. The lack of a pharmacokinetic/pharmacodynamic relationship is potentially an artefact of raltegravir's characteristic high inter and intra-patient variability and also suggesting single time point sampling schedules are inadequate to thoroughly assess the influence of SNPs on raltegravir pharmacokinetics.


Assuntos
Fármacos Anti-HIV , Infecções por HIV , Humanos , Adulto , Raltegravir Potássico/uso terapêutico , Raltegravir Potássico/farmacologia , Fármacos Anti-HIV/uso terapêutico , Fármacos Anti-HIV/farmacologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/genética , Infecções por HIV/epidemiologia , Polimorfismo Genético , Carga Viral/genética
5.
J Acquir Immune Defic Syndr ; 79(4): 481-490, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30365452

RESUMO

BACKGROUND: The NEAT001/ANRS143 trial demonstrated noninferiority of ritonavir-boosted darunavir combined with either raltegravir (RAL + DRV/r) or tenofovir disoproxil fumarate/emtricitabine (TDF/FTC + DRV/r) in HIV-positive, antiretroviral-naive adults. In post hoc analyses, however, RAL + DRV/r showed inferiority in patients with baseline CD4 <200/mm and HIV-1 RNA ≥100,000 copies per milliliter. This preplanned ancillary study was conducted to assess whether differences in adherence might explain efficacy results. SETTING: Phase III, open-label, randomized, multicenter study in 15 European countries (ClinicalTrials.gov, NCT01066962). METHODS: Seven hundred seventy-four participants self-reported adherence (modified AIDS Clinical Trials Group questionnaire) over 96 weeks [383 RAL + DRV/r (twice daily; 5 pills/day), 391 TDF/FTC + DRV/r (once daily; 4 pills/day)]. Primary endpoint was ≥95% versus <95% adherence to prescribed doses recorded (1) over the last 4 days or (2) on the visual analogue scale over the last 30 days. RESULTS: Characteristics, except age, were similar between arms; 9% had CD4 <200 cells/mm and HIV-1 RNA ≥100,000 copies per milliliter. Adherence ≥95% in the last 4 days (P = 0.029) or at the visual analogue scale (P = 0.0072) was higher with TDF/FTC + DRV/r than with RAL + DRV/r. Adherence ≥95% over the last 4 days was associated with lower probability of virological failure (P = 0.015). Adherence in patients with baseline CD4 <200 cells/mm and HIV-1 RNA ≥100,000 copies per milliliter was similar to the rest of the population, and not significantly associated with efficacy measures, with no significant differences between arms. CONCLUSION: Adherence was high and slightly better in the TDF/FTC + DRV/r than in the RAL + DRV/r arm. No convincing evidence was found that higher failure rate in the RAL + DRV/r arm in the subgroup with worse baseline viroimmunological status is caused by adherence differences.


Assuntos
Antirretrovirais/uso terapêutico , Terapia Antirretroviral de Alta Atividade/métodos , Infecções por HIV/tratamento farmacológico , Adesão à Medicação/estatística & dados numéricos , Humanos , Falha de Tratamento
6.
J Infect Dis ; 218(10): 1523-1530, 2018 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-29982509

RESUMO

Background: Tenofovir is a potent inhibitor of human telomerase. The clinical relevance of this inhibition is unknown. Methods: NEAT001/ANRS143 is a randomized trial that showed noninferiority over 96 weeks of ritonavir-boosted darunavir plus raltegravir versus tenofovir disoproxil fumarate/emtricitabine in 805 antiretroviral antiretrovrial-naive HIV-infected adults. We compared changes in whole-blood telomere length measured with quantitative polymerase chain reaction in 201 randomly selected participants (104 raltegravir and 97 tenofovir disoproxil fumarate/emtricitabine). We performed multivariable estimative and predictive linear regression. Results: At week 96, participants receiving tenofovir disoproxil fumarate/emtricitabine had a statistically significant higher gain in telomere length than participants receiving raltegravir. Difference in mean telomere length change between groups (tenofovir disoproxil fumarate/emtricitabine minus raltegravir) from baseline to week 96 adjusted by baseline telomere length was 0.031 (P = .009). This difference was not significantly confounded by age, gender, known duration of HIV infection, CD4 (baseline/nadir), CD8 cells, CD4/CD8 ratio, HIV viral load (baseline/week 96), tobacco and alcohol consumption, statins, or hepatitis C. Conclusion: Antiretroviral-naive HIV-infected adults receiving ritonavir-boosted darunavir and tenofovir disoproxil fumarate/emtricitabine had a significant higher gain in blood telomere length than those receiving ritonavir-boosted darunavir and raltegravir, suggesting a better initial recovery from HIV-associated immunosenescence.


Assuntos
Fármacos Anti-HIV , Infecções por HIV , Telômero/efeitos dos fármacos , Adulto , Análise de Variância , Fármacos Anti-HIV/administração & dosagem , Fármacos Anti-HIV/farmacologia , Fármacos Anti-HIV/uso terapêutico , DNA/sangue , Darunavir/administração & dosagem , Darunavir/farmacologia , Darunavir/uso terapêutico , Emtricitabina/administração & dosagem , Emtricitabina/farmacologia , Emtricitabina/uso terapêutico , Feminino , Infecções por HIV/sangue , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Infecções por HIV/genética , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Raltegravir Potássico/administração & dosagem , Raltegravir Potássico/farmacologia , Raltegravir Potássico/uso terapêutico , Ensaios Clínicos Controlados Aleatórios como Assunto , Ritonavir/administração & dosagem , Ritonavir/farmacologia , Ritonavir/uso terapêutico , Tenofovir/administração & dosagem , Tenofovir/farmacologia , Tenofovir/uso terapêutico
8.
BMC Infect Dis ; 16(1): 654, 2016 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-27825316

RESUMO

BACKGROUND: Few studies have evaluated the impact of pre-treatment drug resistance (PDR) on response to combination antiretroviral treatment (cART) in children. The objective of this joint EuroCoord-CHAIN-EPPICC/PENTA project was to assess the prevalence of PDR mutations and their association with virological outcome in the first year of cART in children. METHODS: HIV-infected children <18 years initiating cART between 1998 and 2008 were included if having at least one genotypic resistance test prior to cART initiation. We used the World Health Organization 2009 resistance mutation list and Stanford algorithm to infer resistance to prescribed drugs. Time to virological failure (VF) was defined as the first of two consecutive HIV-RNA > 500 copies/mL after 6 months cART and was assessed by Cox proportional hazards models. All models were adjusted for baseline demographic, clinical, immunology and virology characteristics and calendar period of cART start and initial cART regimen. RESULTS: Of 476 children, 88 % were vertically infected. At cART initiation, median (interquartile range) age was 6.6 years (2.1-10.1), CD4 cell count 297 cells/mm3 (98-639), and HIV-RNA 5.2 log10copies/mL (4.7-5.7). Of 37 children (7.8 %, 95 % confidence interval (CI), 5.5-10.6) harboring a virus with ≥1 PDR mutations, 30 children had a virus resistant to ≥1 of the prescribed drugs. Overall, the cumulative Kaplan-Meier estimate for virological failure was 19.8 % (95 %CI, 16.4-23.9). Cumulative risk for VF tended to be higher among children harboring a virus with PDR and resistant to ≥1 drug prescribed than among those receiving fully active cART: 32.1 % (17.2-54.8) versus 19.4 % (15.9-23.6) (P = 0.095). In multivariable analysis, age was associated with a higher risk of VF with a 12 % reduced risk per additional year (HR 0.88; 95 %CI, 0.82-0.95; P < 0.001). CONCLUSIONS: PDR was not significantly associated with a higher risk of VF in children in the first year of cART. The risk of VF decreased by 12 % per additional year at treatment initiation which may be due to fading of PDR mutations over time. Lack of appropriate formulations, in particular for the younger age group, may be an important determinant of virological failure.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Farmacorresistência Viral/efeitos dos fármacos , Infecções por HIV/tratamento farmacológico , Adolescente , Contagem de Linfócito CD4 , Criança , Pré-Escolar , Farmacorresistência Viral/genética , Quimioterapia Combinada , Feminino , Infecções por HIV/mortalidade , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , Humanos , Lactente , Estimativa de Kaplan-Meier , Masculino , Mutação , Inibidores da Transcriptase Reversa/uso terapêutico , Carga Viral/efeitos dos fármacos
9.
J Int AIDS Soc ; 17(4 Suppl 3): 19572, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25394079

RESUMO

INTRODUCTION: NEAT001/ANRS143 was an open-label, randomized, non-inferiority study comparing raltegravir+darunavir/r(RGV+DRV/r) vs. tenofovir/emtricitabine+darunavir/r (TDF/FTC+DRV/r) in HIV-infected antiretroviral naïve adults. Primary efficacy outcome was a composite of virological and clinical events by week 96. MATERIALS AND METHODS: Clinical trial units collected and translated supporting documentation (SD) related to the investigator-reported events. A coordinator checked events and SD for consistency and completeness. The Endpoint Review Committee (ERC) determined if clinical events met pre-defined diagnostic criteria in categories "confirmed" or "probable". The ERC of 12 experienced, independent clinicians served in groups of three conducting individual reviews in writing, blinded to treatment arm. Differences of opinion were adjudicated in a second review by direct dialogue between reviewers. "Confirmed" events required adequate SD like laboratory, radiographic or pathology diagnostic reports. "Probable" events were typically based on clinical criteria. RESULTS: Of the 164 serious and 3,964 adverse events reported in the study, 133 qualified for endpoint review, for a total of 153 adjudications: CONCLUSIONS: Blinded endpoint review prevented unacceptably high false positive event rates documenting that real-time ascertainment of clinical endpoints is crucial for appropriateness of the overall results. Non-confirmed events jeopardize the statistical power in this and probably all kinds of clinical studies. The rejection rate was not indicative of poor study conduct - on the contrary over-reporting prevented missing events, which would have adversely impacted the trial. Adequacy of SD and investigator training on possible differences in event criteria in daily pragmatic clinical management compared to protocol defined criteria is essential.

10.
Lancet ; 384(9958): 1942-51, 2014 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-25103176

RESUMO

BACKGROUND: Standard first-line antiretroviral therapy for HIV-1 infection includes two nucleoside or nucleotide reverse transcriptase inhibitors (NtRTIs), but these drugs have limitations. We assessed the 96 week efficacy and safety of an NtRTI-sparing regimen. METHODS: Between August, 2010, and September, 2011, we enrolled treatment-naive adults into this randomised, open-label, non-inferiority trial in treatment-naive adults in 15 European countries. The composite primary outcome was change to randomised treatment before week 32 because of insufficient virological response, no virological response by week 32, HIV-1 RNA concentration 50 copies per mL or higher at any time after week 32; death from any cause; any new or recurrent AIDS event; or any serious non-AIDS event. Patients were randomised in a 1:1 ratio to receive oral treatment with 400 mg raltegravir twice daily plus 800 mg darunavir and 100 mg ritonavir once daily (NtRTI-sparing regimen) or tenofovir-emtricitabine in a 245 mg and 200 mg fixed-dose combination once daily, plus 800 mg darunavir and 100 mg ritonavir once daily (standard regimen). This trial was registered with ClinicalTrials.gov, number NCT01066962. FINDINGS: Of 805 patients enrolled, 401 received the NtRTI-sparing regimen and 404 the standard regimen, with median follow-up of 123 weeks (IQR 112-133). Treatment failure was seen in 77 (19%) in the NtRTI-sparing group and 61 (15%) in the standard group. Kaplan-Meier estimated proportions of treatment failure by week 96 were 17·8% and 13·8%, respectively (difference 4·0%, 95% CI -0·8 to 8·8). The frequency of serious or treatment-modifying adverse events were similar (10·2 vs 8·3 per 100 person-years and 3·9 vs 4·2 per 100 person-years, respectively). INTERPRETATION: Our NtRTI-sparing regimen was non-inferior to standard treatment and represents a treatment option for patients with CD4 cell counts higher than 200 cells per µL. FUNDING: European Union Sixth Framework Programme, Inserm-ANRS, Gilead Sciences, Janssen Pharmaceuticals, Merck Laboratories.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , HIV-1 , Adenina/análogos & derivados , Adenina/uso terapêutico , Adulto , Contagem de Linfócito CD4 , HDL-Colesterol/metabolismo , LDL-Colesterol/metabolismo , Darunavir , Desoxicitidina/análogos & derivados , Desoxicitidina/uso terapêutico , Farmacorresistência Viral , Quimioterapia Combinada , Emtricitabina , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Organofosfonatos/uso terapêutico , Pirrolidinonas/uso terapêutico , Raltegravir Potássico , Ritonavir/uso terapêutico , Sulfonamidas/uso terapêutico , Tenofovir , Resultado do Tratamento
11.
Biotechnol J ; 1(3): 270-81, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16897707

RESUMO

Mitochondrial diseases are rare diseases most often linked to energy in the form of ATP-depletion. The high number of nuclear- and mitochondrial-DNA-encoded proteins (>500), required for ATP production and other crucial mitochondrial functions such as NADH re-oxidation, explains the increasing number of reported disorders. In recent years, yeast has revealed to be a powerful model to identify responsible genes, to study primary effects of pathogenic mutations and to determine the molecular mechanisms leading to mitochondrial disorders. However, the clinical management of patients with mitochondrial disorders is still essentially supportive. Here we review some of the most fruitful yeast mitochondrial disorder models and propose to subject these models to highthroughput chemical library screening to prospect new therapeutic drugs against mitochondrial diseases.


Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Mitocôndrias/metabolismo , Doenças Mitocondriais/tratamento farmacológico , Doenças Mitocondriais/metabolismo , Proteínas Mitocondriais/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Animais , Bioensaio/métodos , Sistemas de Liberação de Medicamentos/métodos , Desenho de Fármacos , Humanos , Mitocôndrias/efeitos dos fármacos , Biologia Molecular/métodos
12.
J Biol Chem ; 280(35): 30751-9, 2005 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-15975925

RESUMO

In a previous study we have identified Fmc1p, a mitochondrial protein involved in the assembly/stability of the yeast F0F1-ATP synthase at elevated temperatures. The deltafmc1 mutant was shown to exhibit a severe phenotype of very slow growth on respiratory substrates at 37 degrees C. We have isolated ODC1 as a multicopy suppressor of the fmc1 deletion restoring a good respiratory growth. Odc1p expression level was estimated to be at least 10 times higher in mitochondria isolated from the deltafmc1/ODC1 transformant as compared with wild type mitochondria. Interestingly, ODC1 encodes an oxodicarboxylate carrier, which transports alpha-ketoglutarate and alpha-ketoadipate or any other transported tricarboxylic acid cycle intermediate in a counter-exchange through the inner mitochondrial membrane. We show that the suppression of the respiratory-growth-deficient fmc1 by the overexpressed Odc1p was not due to a restored stable ATP synthase. Instead, the rescuing mechanism involves an increase in the flux of tricarboxylic acid cycle intermediate from the cytosol into the mitochondria, leading to an increase in the alpha-ketoglutarate oxidative decarboxylation, resulting in an increase in mitochondrial substrate-level-dependent ATP synthesis. This mechanism of metabolic bypass of a defective ATP synthase unravels the physiological importance of intramitochondrial substrate-level phosphorylations. This unexpected result might be of interest for the development of therapeutic solutions in pathologies associated with defects in the oxidative phosphorylation system.


Assuntos
Respiração Celular/fisiologia , Transportadores de Ácidos Dicarboxílicos/metabolismo , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , ATPases Translocadoras de Prótons/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiologia , Trifosfato de Adenosina/biossíntese , Ciclo do Ácido Cítrico/fisiologia , Transportadores de Ácidos Dicarboxílicos/genética , Estabilidade Enzimática , Potenciais da Membrana/fisiologia , Proteínas Mitocondriais/genética , Fenótipo , Fosforilação , ATPases Translocadoras de Prótons/genética , Saccharomyces cerevisiae/citologia , Proteínas de Saccharomyces cerevisiae/genética , Temperatura
13.
J Bioenerg Biomembr ; 35(3): 243-56, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-13678275

RESUMO

Two distinct conformations of the mitochondrial ADP/ATP carrier involved in the adenine nucleotide transport are called BA and CATR conformations, as they were distinguished by binding of specific inhibitors bongkrekic acid (BA) and carboxyatractyloside (CATR), respectively. To find out which amino acids are implicated in the transition between these two conformations, which occurs during transport, mutants of the Saccharomyces cerevisiae ADP/ATP carrier Anc2p responsible for resistance of yeast cells to BA were identified and characterized after in vivo chemical or UV mutagenesis. Only four different mutations could be identified in spite of a large number of mutants analyzed. They are located in the Anc2p transmembrane segments I (G30S), II (Y97C), III (L142S), and VI (G298S), and are independently enabling growth of cells in the presence of BA. The variant and wild-type Anc2p were produced practically to the same level in mitochondria, as evidenced by immunochemical analysis and by atractyloside binding experiments. ADP/ATP exchange mediated by Anc2p variants in isolated mitochondria was more efficient than that of the wild-type Anc2p in the presence of BA, confirming that BA resistance of the mutant cells was linked to the functional properties of the modified ADP/ATP carrier. These results suggest that resistance to BA is caused by alternate conformation of Anc2p due to appearance of Ser or Cys at specific positions. Different interactions of these residues with other amino acids and/or BA could prevent formation of stable inactive Anc2p . BA complex.


Assuntos
Atractilosídeo/análogos & derivados , Ácido Bongcréquico/farmacologia , Farmacorresistência Bacteriana/genética , Translocases Mitocondriais de ADP e ATP/antagonistas & inibidores , Translocases Mitocondriais de ADP e ATP/genética , Mutação Puntual/fisiologia , Antibacterianos/farmacologia , Atractilosídeo/farmacologia , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/química , Proteínas de Membrana/genética , Translocases Mitocondriais de ADP e ATP/química , Proteínas Mitocondriais/antagonistas & inibidores , Proteínas Mitocondriais/química , Proteínas Mitocondriais/genética , Conformação Proteica , Proteínas de Saccharomyces cerevisiae
14.
Mol Cell Biol ; 22(11): 3590-8, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11997496

RESUMO

The yeast [PSI(+)], [URE3], and [PIN(+)] genetic elements are prion forms of Sup35p, Ure2p, and Rnq1p, respectively. Overexpression of Sup35p, Ure2p, or Rnq1p leads to increased de novo appearance of [PSI(+)], [URE3], and [PIN(+)], respectively. This inducible appearance of [PSI(+)] was shown to be dependent on the presence of [PIN(+)] or [URE3] or overexpression of other yeast proteins that have stretches of polar residues similar to the prion-determining domains of the known prion proteins. In a similar manner, [PSI(+)] and [URE3] facilitate the appearance of [PIN(+)]. In contrast to these positive interactions, here we find that in the presence of [PIN(+)], [PSI(+)] and [URE3] repressed each other's propagation and de novo appearance. Elevated expression of Hsp104 and Hsp70 (Ssa2p) had little effect on these interactions, ruling out competition between the two prions for limiting amounts of these protein chaperones. In contrast, we find that constitutive overexpression of SSA1 but not SSA2 cured cells of [URE3], uncovering a specific interaction between Ssa1p and [URE3] and a functional distinction between these nearly identical Hsp70 isoforms. We also find that Hsp104 abundance, which critically affects [PSI(+)] propagation, is elevated when [URE3] is present. Our results are consistent with the notion that proteins that have a propensity to form prions may interact with heterologous prions but, as we now show, in a negative manner. Our data also suggest that differences in how [PSI(+)] and [URE3] interact with Hsp104 and Hsp70 may contribute to their antagonistic interactions.


Assuntos
Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Proteínas de Choque Térmico HSP70/metabolismo , Príons/genética , Príons/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Adenosina Trifosfatases , Genes Fúngicos , Variação Genética , Glutationa Peroxidase , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Fatores de Terminação de Peptídeos , Regiões Promotoras Genéticas , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento
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