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1.
N Engl J Med ; 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38828933

RESUMO

BACKGROUND: Belantamab mafodotin had single-agent activity in patients with relapsed or refractory multiple myeloma, a finding that supports further evaluation of the agent in combination with standard-care therapies. METHODS: In this phase 3, open-label, randomized trial, we evaluated belantamab mafodotin, bortezomib, and dexamethasone (BVd), as compared with daratumumab, bortezomib, and dexamethasone (DVd), in patients who had progression of multiple myeloma after at least one line of therapy. The primary end point was progression-free survival. Key secondary end points were overall survival, response duration, and minimal residual disease (MRD)-negative status. RESULTS: In total, 494 patients were randomly assigned to receive BVd (243 patients) or DVd (251 patients). At a median follow-up of 28.2 months (range, 0.1 to 40.0), median progression-free survival was 36.6 months (95% confidence interval [CI], 28.4 to not reached) in the BVd group and 13.4 months (95% CI, 11.1 to 17.5) in the DVd group (hazard ratio for disease progression or death, 0.41; 95% CI, 0.31 to 0.53; P<0.001). Overall survival at 18 months was 84% in the BVd group and 73% in the DVd group. An analysis of the restricted mean response duration favored BVd over DVd (P<0.001). A complete response or better plus MRD-negative status occurred in 25% of the patients in the BVd group and 10% of those in the DVd group. Grade 3 or higher adverse events occurred in 95% of the patients in the BVd group and 78% of those in the DVd group. Ocular events were more common in the BVd group than in the DVd group (79% vs. 29%); such events were managed with dose modifications, and events of worsening visual acuity mostly resolved. CONCLUSIONS: As compared with DVd therapy, BVd therapy conferred a significant benefit with respect to progression-free survival among patients who had relapsed or refractory multiple myeloma after at least one line of therapy. Most patients had grade 3 or higher adverse events. (Funded by GSK; DREAMM-7 ClinicalTrials.gov number, NCT04246047; EudraCT number, 2018-003993-29.).

2.
Cancer ; 129(23): 3746-3760, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37622738

RESUMO

BACKGROUND: Patients with relapsed/refractory multiple myeloma (RRMM) have a high unmet treatment need. Belantamab mafodotin (belamaf), a first-in-class, B-cell maturation antigen-binding antibody-drug conjugate, eliminates myeloma cells through direct cell killing and an anti-myeloma immune response. METHODS: DREAMM-2 (NCT03525678) was a phase 2, two-arm, open-label trial in patients with heavily pretreated RRMM who had three or more prior therapies, were refractory to an immunomodulatory agent and a proteasome inhibitor, and refractory or intolerant to an anti-CD38 monoclonal antibody. Belamaf was given at 2.5 or 3.4 mg/kg every 3 weeks. The primary end point was overall response rate (ORR); secondary end points included progression-free survival (PFS), overall survival (OS), safety, ocular symptoms, and health-related quality of life (HRQOL). RESULTS: This final analysis (cutoff date, March 31, 2022), N = 223, with median follow-up of 12.5 and 13.8 months, demonstrated an ORR of 32% and 35%, median PFS of 2.8 and 3.9 months, and median OS of 15.3 and 14.0 months in the 2.5 mg/kg and 3.4 mg/kg cohorts, respectively. Median duration of response was 12.5 and 6.2 months. No new safety signals were observed; the most common Grade 3 and 4 adverse events were keratopathy (29% vs. 25%), thrombocytopenia (22% vs. 29%), and anemia (21% vs. 28%). HRQOL outcomes suggest that overall global health status/quality of life, physical and role functioning, and overall disease symptoms were maintained or improved during treatment. CONCLUSIONS: This final analysis of DREAMM-2 confirms that in patients with triple-class refractory RRMM, single-agent belamaf results in durable and clinically meaningful responses with a manageable safety profile.


Assuntos
Mieloma Múltiplo , Humanos , Qualidade de Vida , Resultado do Tratamento , Anticorpos Monoclonais Humanizados/uso terapêutico
3.
Eval Program Plann ; 99: 102284, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37209641

RESUMO

The current study builds the evidence base on the effects of Summer Youth Employment Programs (SYEP) both geographically and methodologically by linking SYEP participant records to a comprehensive integrated longitudinal database to better understand programmatic impacts on youth who completed participation in an SYEP in Cleveland, Ohio. The study matches SYEP participants and unselected applicants on various observed covariates using the Child Household Integrated Longitudinal Data (CHILD) System and relies upon propensity score matching techniques to estimate program completion impacts on educational and criminal justice system involvement outcomes. SYEP completion is associated with a lower prevalence of juvenile offense filings and incarceration events, better school attendance, and improved graduation rates 1-2 years following program participation.


Assuntos
Direito Penal , Emprego , Humanos , Adolescente , Ohio , Avaliação de Programas e Projetos de Saúde , Escolaridade
4.
Adv Exp Med Biol ; 1362: 73-84, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35288874

RESUMO

The underlying role of inadequate or excess intake of phosphate is evident in disease states, including metabolic, skeletal, cardiac, kidney and various cancers. Elevated phosphate levels can induce epithelial to mesenchymal transition (EMT) and cell death. EMT and associated lethal, metastatic or fibrinogenic responses are known to be underlying disease processes in fibrotic diseases and various solid tumors. Studies have shown EMT is regulated by induction of different signaling pathways, including TGF-ß, RTK, SRC, Wnt and Notch signal transduction. However, cross-talk amongst these signaling pathways is less understood. We have shown that elevated phosphate levels enhanced EMT partially through activating ERK1/2 pathway, resulting in massive cell death. We thus proposed excess phosphate-mediated lethal EMT as one of the underlying mechanisms of phosphate-induced cytotoxicity, which could explain high phosphate-associated renal fibrosis and cancer metastasis in preclinical and clinical studies. This chapter provides the overview of EMT with the highlights of its regulation by various signaling pathways induced by phosphate toxicity. We further put lately reported lethal EMT in the context of phosphate toxicity with the intent to explain it to excessive phosphate-associated pathologies.


Assuntos
Transição Epitelial-Mesenquimal , Fator de Crescimento Transformador beta , Fibrose , Humanos , Fosfatos/toxicidade , Transdução de Sinais , Fator de Crescimento Transformador beta/metabolismo
5.
Cancer ; 127(22): 4198-4212, 2021 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-34314018

RESUMO

BACKGROUND: On the basis of the DREAMM-2 study (ClinicalTrials.gov identifier NCT03525678), single-agent belantamab mafodotin (belamaf) was approved for patients with relapsed or refractory multiple myeloma (RRMM) who received ≥4 prior therapies, including anti-CD38 therapy. The authors investigated longer term efficacy and safety outcomes in DREAMM-2 after 13 months of follow-up among patients who received belamaf 2.5 mg/kg. METHODS: DREAMM-2 is an ongoing, phase 2, open-label, 2-arm study investigating belamaf (2.5 or 3.4 mg/kg) in patients with RRMM who had disease progression after ≥3 lines of therapy and were refractory to immunomodulatory drugs and proteasome inhibitors and refractory and/or intolerant to an anti-CD38 therapy. The primary outcome was the proportion of patients that achieved an overall response, assessed by an independent review committee. RESULTS: As of January 31, 2020, 10% of patients still received belamaf 2.5 mg/kg. Thirty-one of 97 patients (32%; 97.5% confidence interval [CI], 21.7%-43.6%) achieved an overall response, and 18 responders achieved a very good partial response or better. Median estimated duration of response, overall survival, and progression-free survival were 11.0 months (95% CI, 4.2 months to not reached), 13.7 months (95% CI, 9.9 months to not reached), and 2.8 months (95% CI, 1.6-3.6 months), respectively. Response and survival outcomes in patients who had high-risk cytogenetics or renal impairment were consistent with outcomes in the overall population. Outcomes were poorer in patients with extramedullary disease. In patients who had a clinical response and prolonged dose delays (>63 days; mainly because of corneal events), 88% maintained or deepened responses during their first prolonged dose delay. Overall, there were no new safety signals during this follow-up. CONCLUSIONS: Extended follow-up confirms sustained clinical activity without new safety signals with belamaf in this heavily pretreated patient population with RRMM.


Assuntos
Mieloma Múltiplo , Anticorpos Monoclonais Humanizados/uso terapêutico , Seguimentos , Humanos , Mieloma Múltiplo/tratamento farmacológico , Intervalo Livre de Progressão
6.
Neuron ; 107(4): 631-643.e5, 2020 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-32516574

RESUMO

A major challenge for miniature bioelectronics is wireless power delivery deep inside the body. Electromagnetic or ultrasound waves suffer from absorption and impedance mismatches at biological interfaces. On the other hand, magnetic fields do not suffer these losses, which has led to magnetically powered bioelectronic implants based on induction or magnetothermal effects. However, these approaches have yet to produce a miniature stimulator that operates at clinically relevant high frequencies. Here, we show that an alternative wireless power method based on magnetoelectric (ME) materials enables miniature magnetically powered neural stimulators that operate up to clinically relevant frequencies in excess of 100 Hz. We demonstrate that wireless ME stimulators provide therapeutic deep brain stimulation in a freely moving rodent model for Parkinson's disease and that these devices can be miniaturized to millimeter-scale and fully implanted. These results suggest that ME materials are an excellent candidate to enable miniature bioelectronics for clinical and research applications.


Assuntos
Estimulação Encefálica Profunda/instrumentação , Neuroestimuladores Implantáveis , Tecnologia sem Fio/instrumentação , Animais , Desenho de Equipamento , Humanos
7.
Ther Innov Regul Sci ; 54(4): 821-830, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32557298

RESUMO

Evaluation of the safety profile of medicines is moving from a more reactive approach, where safety experts and statisticians have been primarily focusing on the review of clinical trial data and spontaneous reports, to a more proactive endeavor with cross-functional teams strategically evolving their understanding of the safety profile. They do this by anticipating the ultimate benefit-risk profile and its related risk management implications from the start of development. The proposed approach is based on assessments of integrated program-level safety data. These data stem from multiple sources such as preclinical information; clinical and spontaneous adverse event reports; epidemiological, real-world, and registry data; as well as, potentially, data from social media. Blended qualitative and quantitative evaluations allow integration of data from diverse sources. Adding to this, a collaborative multidisciplinary view, which is focused on continuous learning and decision-making via diverse safety management teams, ensures that companies look at their growing safety database and associated risk management implications from every relevant perspective. This multifaceted and iterative approach starts early in the development of a new medicine, continues into the post-marketing setting, and wanes as the product matures and the safety profile becomes more well understood. Not only does this satisfy regulatory requirements but, crucially, it provides the healthcare system and treated patients with a better understanding of the drug's safety profile.


Assuntos
Gestão de Riscos , Atenção à Saúde , Humanos , Saúde Pública , Medição de Risco
8.
Lancet Oncol ; 21(2): 207-221, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31859245

RESUMO

BACKGROUND: Belantamab mafodotin (GSK2857916), an immunoconjugate targeting B-cell maturation antigen, showed single-agent activity in the phase 1 DREAMM-1 study in heavily pre-treated patients with relapsed or refractory multiple myeloma. We further investigated the safety and activity of belantamab mafodotin in the DREAMM-2 study. METHODS: DREAMM-2 is an open-label, two-arm, phase 2 study done at 58 multiple myeloma specialty centres in eight countries. Patients (aged ≥18 years) with relapsed or refractory multiple myeloma with disease progression after three or more lines of therapy and who were refractory to immunomodulatory drugs and proteasome inhibitors, and refractory or intolerant (or both) to an anti-CD38 monoclonal antibody with an Eastern Cooperative Oncology Group performance status of 0-2 were recruited, centrally randomly assigned (1:1) with permuted blocks (block size 4), and stratified by previous lines of therapy (≤4 vs >4) and cytogenetic features to receive 2·5 mg/kg or 3·4 mg/kg belantamab mafodotin via intravenous infusion every 3 weeks on day 1 of each cycle until disease progression or unacceptable toxicity. The intention-to-treat population comprised all randomised patients, regardless of treatment administration. The safety population comprised all patients who received at least one dose of belantamab mafodotin. The primary outcome was the proportion of randomly assigned patients in the intention-to-treat population who achieved an overall response, as assessed by an independent review committee. This study is registered with ClinicalTrials.gov, NCT03525678, and is ongoing. FINDINGS: Between June 18, 2018, and Jan 2, 2019, 293 patients were screened and 196 were included in the intention-to-treat population (97 in the 2·5 mg/kg cohort and 99 in the 3·4 mg/kg cohort). As of June 21, 2019 (the primary analysis data cutoff date), 30 (31%; 97·5% CI 20·8-42·6) of 97 patients in the 2·5 mg/kg cohort and 34 (34%; 23·9-46·0) of 99 patients in the 3·4 mg/kg cohort achieved an overall response. The most common grade 3-4 adverse events in the safety population were keratopathy (in 26 [27%] of 95 patients in the 2·5 mg/kg cohort and 21 [21%] of 99 patients in the 3·4 mg/kg cohort), thrombocytopenia (19 [20%] and 33 [33%]), and anaemia (19 [20%] and 25 [25%]); 38 (40%) of 95 patients in the 2·5 mg/kg cohort and 47 (47%) of 99 in the 3·4 mg/kg cohort reported serious adverse events. Two deaths were potentially treatment related (one case of sepsis in the 2·5 mg/kg cohort and one case of haemophagocytic lymphohistiocytosis in the 3·4 mg/kg cohort). INTERPRETATION: Single-agent belantamab mafodotin shows anti-myeloma activity with a manageable safety profile in patients with relapsed or refractory multiple myeloma. FUNDING: GlaxoSmithKline.


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Antineoplásicos Imunológicos/uso terapêutico , Mieloma Múltiplo/tratamento farmacológico , Adolescente , Adulto , Idoso , Anticorpos Monoclonais Humanizados/efeitos adversos , Antineoplásicos Imunológicos/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mieloma Múltiplo/mortalidade , Mieloma Múltiplo/patologia , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
9.
J Biol Chem ; 293(38): 14707-14722, 2018 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-30093403

RESUMO

Apoptosis-inducing factor (AIF) is a mitochondrial flavoprotein occasionally involved in cell death that primarily regulates mitochondrial energy metabolism under normal cellular conditions. AIF catalyzes the oxidation of NADH in vitro, yet the significance of this redox activity in cells remains unclear. Here, we show that through its enzymatic activity AIF is a critical factor for oxidative stress-induced activation of the mitogen-activated protein kinases JNK1 (c-Jun N-terminal kinase), p38, and ERK (extracellular signal-regulated kinase). AIF-dependent JNK1 signaling culminates in the cadherin switch, and genetic reversal of this switch leads to apoptosis when AIF is suppressed. Notably, this widespread ability of AIF to promote JNK signaling can be uncoupled from its more limited role in respiratory chain stabilization. Thus, AIF is a transmitter of extra-mitochondrial signaling cues with important implications for human development and disease.


Assuntos
Antígenos CD/metabolismo , Fator de Indução de Apoptose/fisiologia , Caderinas/metabolismo , Transporte de Elétrons , Proteína Quinase 8 Ativada por Mitógeno/metabolismo , Apoptose , Catálise , Linhagem Celular , Metabolismo Energético , Ativação Enzimática , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Mitocôndrias/enzimologia , Mitocôndrias/metabolismo , Oxidantes/metabolismo , Oxirredução , Estresse Oxidativo , Fosforilação , Transdução de Sinais , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
10.
Neurology ; 90(20): e1805-e1814, 2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-29695594

RESUMO

OBJECTIVE: To assess dose-response effects of the anti-CD20 monoclonal antibody ofatumumab on efficacy and safety outcomes in a phase 2b double-blind study of relapsing forms of multiple sclerosis (RMS). METHODS: Patients (n = 232) were randomized to ofatumumab 3, 30, or 60 mg every 12 weeks, ofatumumab 60 mg every 4 weeks, or placebo for a 24-week treatment period, with a primary endpoint of cumulative number of new gadolinium-enhancing lesions (per brain MRI) at week 12. Relapses and safety/tolerability were assessed, and CD19+ peripheral blood B-lymphocyte counts measured. Safety monitoring continued weeks 24 to 48 with subsequent individualized follow-up evaluating B-cell repletion. RESULTS: The cumulative number of new lesions was reduced by 65% for all ofatumumab dose groups vs placebo (p < 0.001). Post hoc analysis (excluding weeks 1-4) estimated a ≥90% lesion reduction vs placebo (week 12) for all cumulative ofatumumab doses ≥30 mg/12 wk. Dose-dependent CD19 B-cell depletion was observed. Notably, complete depletion was not necessary for a robust treatment effect. The most common adverse event was injection-related reactions (52% ofatumumab, 15% placebo), mild to moderate severity in 97%, most commonly associated with the first dose and diminishing on subsequent dosing. CONCLUSION: Imaging showed that all subcutaneous ofatumumab doses demonstrated efficacy (most robust: cumulative doses ≥30 mg/12 wk), with a safety profile consistent with existing ofatumumab data. This treatment effect also occurred with dosage regimens that only partially depleted circulating B cells. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that for patients with RMS, ofatumumab decreases the number of new MRI gadolinium-enhancing lesions 12 weeks after treatment initiation.


Assuntos
Anticorpos Monoclonais/administração & dosagem , Antineoplásicos/administração & dosagem , Injeções Subcutâneas , Esclerose Múltipla Recidivante-Remitente/tratamento farmacológico , Acetaminofen/administração & dosagem , Administração Oral , Adulto , Analgésicos não Narcóticos/administração & dosagem , Anticorpos Monoclonais Humanizados , Avaliação da Deficiência , Método Duplo-Cego , Feminino , Seguimentos , Antagonistas dos Receptores Histamínicos/administração & dosagem , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla Recidivante-Remitente/diagnóstico por imagem , Fatores de Tempo
11.
Nature ; 554(7692): 398, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32094733
12.
Nano Lett ; 18(1): 326-335, 2018 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-29220192

RESUMO

Soft and conductive nanomaterials like carbon nanotubes, graphene, and nanowire scaffolds have expanded the family of ultraflexible microelectrodes that can bend and flex with the natural movement of the brain, reduce the inflammatory response, and improve the stability of long-term neural recordings. However, current methods to implant these highly flexible electrodes rely on temporary stiffening agents that temporarily increase the electrode size and stiffness thus aggravating neural damage during implantation, which can lead to cell loss and glial activation that persists even after the stiffening agents are removed or dissolve. A method to deliver thin, ultraflexible electrodes deep into neural tissue without increasing the stiffness or size of the electrodes will enable minimally invasive electrical recordings from within the brain. Here we show that specially designed microfluidic devices can apply a tension force to ultraflexible electrodes that prevents buckling without increasing the thickness or stiffness of the electrode during implantation. Additionally, these "fluidic microdrives" allow us to precisely actuate the electrode position with micron-scale accuracy. To demonstrate the efficacy of our fluidic microdrives, we used them to actuate highly flexible carbon nanotube fiber (CNTf) microelectrodes for electrophysiology. We used this approach in three proof-of-concept experiments. First, we recorded compound action potentials in a soft model organism, the small cnidarian Hydra. Second, we targeted electrodes precisely to the thalamic reticular nucleus in brain slices and recorded spontaneous and optogenetically evoked extracellular action potentials. Finally, we inserted electrodes more than 4 mm deep into the brain of rats and detected spontaneous individual unit activity in both cortical and subcortical regions. Compared to syringe injection, fluidic microdrives do not penetrate the brain and prevent changes in intracranial pressure by diverting fluid away from the implantation site during insertion and actuation. Overall, the fluidic microdrive technology provides a robust new method to implant and actuate ultraflexible neural electrodes.


Assuntos
Dispositivos Lab-On-A-Chip , Nanotubos de Carbono/química , Neurônios/fisiologia , Potenciais de Ação , Animais , Encéfalo/fisiologia , Elasticidade , Desenho de Equipamento , Hydra/fisiologia , Microeletrodos , Ratos
13.
PLoS One ; 12(4): e0175983, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28414823

RESUMO

Burkholderia pseudomallei (Bpm) is a saprophytic rod-shaped gram-negative bacterium and the causative agent of melioidosis. This disease has previously been described as endemic in areas such as northern Australia and Southeast Asia, but, more recently, a better understanding of the epidemiology of melioidosis indicated that the disease is distributed worldwide, including regions of the Americas and Africa. A 16S-23S rDNA internal transcribed spacer (ITS) typing system has been developed for Bpm and has revealed that ITS types C, E, and hybrid CE are mainly associated with Australia and Southeast Asia while type G strains are more associated with cases of melioidosis in the Western Hemisphere. The purpose of the current study was to determine the in vitro and in vivo virulence profiles of the understudied Bpm type G strains Ca2009, Ca2013a, Mx2013, and 724644 and compared such phenotypes to the commonly studied Bpm type C strain K96243. We evaluated virulence by measuring invasion/uptake and survival of these Bpm strains in murine respiratory epithelial LA-4 cells and alveolar macrophage MH-S cells using different multiplicity of infections (MOIs of 1 and 10). We also calculated the lethal dose 50 values (LD50) in BALB/c mice that were inoculated intranasally with either Ca2009, Ca2013a, or Mx2013. Overall, the virulence and lethality phenotypes of Bpm type G strains were similar to the Bpm type C strain K96243. Additional comparative analyses between the Bpm ITS types may lead to a better understanding of the contribution of the ITS type to the epidemiology and ecology of Bpm strains.


Assuntos
Burkholderia pseudomallei/genética , Virulência/genética , África , Animais , Sudeste Asiático , Austrália , Modelos Animais de Doenças , Feminino , Macrófagos/microbiologia , Melioidose/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Fenótipo
14.
Pathog Dis ; 74(6)2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27440810

RESUMO

The Gram-negative proteobacteria genus Burkholderia encompasses multiple bacterial species that are pathogenic to humans and other vertebrates. Two pathogenic species of interest within this genus are Burkholderia pseudomallei (Bpm) and the B. cepacia complex (Bcc); the former is the causative agent of melioidosis in humans and other mammals, and the latter is associated with pneumonia in immunocompromised patients. One understudied and shared characteristic of these two pathogenic groups is their ability to persist and establish chronic infection within the host. In this review, we will explore the depth of knowledge about chronic infections caused by persistent Bpm and Bcc. We examine the host risk factors and immune responses associated with more severe chronic infections. We also discuss host adaptation and phenotypes associated with persistent Burkholderia species. Lastly, we survey how other intracellular bacteria associated with chronic infections are combatted and explore possible future applications to target Burkholderia Our goal is to highlight understudied areas that should be addressed for a more thorough understanding of chronic Burkholderia infections and how to combat them.


Assuntos
Infecções por Burkholderia/imunologia , Infecções por Burkholderia/microbiologia , Burkholderia/fisiologia , Adaptação Biológica , Animais , Burkholderia/classificação , Burkholderia/patogenicidade , Doença Crônica , Interações Hospedeiro-Patógeno , Humanos , Sistema Imunitário/citologia , Sistema Imunitário/imunologia , Sistema Imunitário/metabolismo , Melioidose/imunologia , Melioidose/microbiologia , Fatores de Virulência
15.
Biochemistry ; 55(23): 3285-302, 2016 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-27218139

RESUMO

Apoptosis inducing factor (AIF) plays a well-defined role in controlling cell death but is also a critical factor for maintaining mitochondrial energy homeostasis; how these dueling activities are balanced has remained largely elusive. To identify new AIF binding partners that may define the continuum of AIF cellular regulation, a biochemical screen was performed that identified the mitochondrial phosphoglycerate mutase 5 (PGAM5) as an AIF associated factor. AIF binds both the short and long isoforms of PGAM5 and can reduce the ability of PGAM5 to control antioxidant responses. Transient overexpression of either PGAM5 isoform triggers caspase activation and cell death, and while AIF could reduce this caspase activation neither AIF expression nor caspase activity is required for PGAM5-mediated death. PGAM5 toxicity morphologically and biochemically resembles mitophagic cell death and is inhibited by the AIF binding protein X-linked inhibitor of apoptosis (XIAP) in a manner that depends on the ubiquitin ligase activity of XIAP. The phosphatase activity of PGAM5 was not required for cell death, and comparison of phosphatase activity between short and long PGAM5 isoforms suggested that only the long isoform is catalytically competent. This property correlated with an increased ability of PGAM5L to form dimers and/or higher order oligomers in intact cells compared to PGAM5S. Overall this study identifies an AIF/PGAM5/XIAP axis that can regulate PGAM5 activities related to the antioxidant response and mitophagy.


Assuntos
Fator de Indução de Apoptose/metabolismo , Apoptose , Ligases/metabolismo , Mitocôndrias/patologia , Proteínas Mitocondriais/metabolismo , Fosfoproteínas Fosfatases/metabolismo , Ubiquitinas/metabolismo , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/metabolismo , Caspases/metabolismo , Células HEK293 , Humanos , Potencial da Membrana Mitocondrial , Microscopia Eletrônica de Transmissão , Mitocôndrias/metabolismo , Isoformas de Proteínas , Ubiquitinação
17.
PLoS One ; 11(2): e0149889, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26918760

RESUMO

Borrelia hermsii, a spirochete and cause of relapsing fever, is notable for its immune evasion by multiphasic antigenic variation within its vertebrate host. This is based on a diverse repertoire of surface antigen genes, only one of which is expressed at a time. Another major surface protein, the Variable Tick Protein (Vtp), is expressed in the tick vector and is invariable at its genetic locus. Given the limited immune systems of ticks, the finding of considerable diversity among the Vtp proteins of different strains of B. hermsii was unexpected. We investigated one explanation for this diversity of Vtp proteins, namely expression of the protein in mammals and a consequent elicitation of a specific immune response. Mice were infected with B. hermsii of either the HS1 or CC1 strain, which have antigenically distinctive Vtp proteins but otherwise have similar repertoires of the variable surface antigens. Subsequently collected sera were examined for antibody reactivities against Vtp and other antigens using Western blot analysis, dot blot, and protein microarray. Week-6 sera of infected mice contained antibodies that were largely specific for the Vtp of the infecting strain and were not attributable to antibody cross-reactivities. The antibody responses of the mice infected with different strains were otherwise similar. Further evidence of in vivo expression of the vtp gene was from enumeration of cDNA sequence reads that mapped to a set of selected B. hermsii genes. This measure of transcription of the infecting strain's vtp gene was ~10% of that for the abundantly-expressed, serotype-defining variable antigen gene but similar to that of genes known for in vivo expression. The findings of Vtp expression in a vertebrate host and elicitation of a specific anti-Vtp antibody response support the view that balancing selection by host adaptive immunity accounts in part for the observed diversity of Vtp proteins.


Assuntos
Proteínas da Membrana Bacteriana Externa/imunologia , Borrelia/imunologia , Ornithodoros/microbiologia , Febre Recorrente/microbiologia , Animais , Anticorpos Antibacterianos/imunologia , Anticorpos Monoclonais/imunologia , Variação Antigênica/genética , Variação Antigênica/imunologia , Antígenos de Bactérias/imunologia , Proteínas da Membrana Bacteriana Externa/genética , Sequência de Bases , Modelos Animais de Doenças , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos SCID , Análise de Sequência de DNA , Transcrição Gênica/genética
18.
Vet Sci ; 3(3)2016 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-29056727

RESUMO

Most Borrelia species that cause tick-borne relapsing fever utilize rodents as their natural reservoirs, and for decades laboratory-bred rodents have served as informative experimental models for the disease. However, while there has much progress in understanding the pathogenetic mechanisms, including antigenic variation, of the pathogen, the host side of the equation has been neglected. Using different approaches, we studied, in immunocompetent inbred mice, the dynamics of infection with and host responses to North American relapsing fever agent B. hermsii. The spirochete's generation time in blood of infected mice was between 4-5 h and, after a delay, was matched in rate by the increase of specific agglutinating antibodies in response to the infection. After initiating serotype cells were cleared by antibodies, the surviving spirochetes were a different serotype and, as a population, grew more slowly. The retardation was attributable to the host response and not an inherently slower growth rate. The innate responses at infection peak and immediate aftermath were characterized by elevations of both pro-inflammatory and anti-inflammatory cytokines and chemokines. Immunodeficient mice had higher spirochete burdens and severe anemia, which was accounted for by aggregation of erythrocytes by spirochetes and their partially reversible sequestration in greatly enlarged spleens and elsewhere.

19.
Antimicrob Agents Chemother ; 59(12): 7249-54, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26369964

RESUMO

Coccidioidomycosis, or valley fever, is a growing health concern endemic to the southwestern United States. Safer, more effective, and more easily administered drugs are needed especially for severe, chronic, or unresponsive infections. The novel fungal CYP51 inhibitor VT-1161 demonstrated in vitro antifungal activity, with MIC50 and MIC90 values of 1 and 2 µg/ml, respectively, against 52 Coccidioides clinical isolates. In the initial animal study, oral doses of 10 and 50 mg/kg VT-1161 significantly reduced fungal burdens and increased survival time in a lethal respiratory model in comparison with treatment with a placebo (P < 0.001). Oral doses of 25 and 50 mg/kg VT-1161 were similarly efficacious in the murine central nervous system (CNS) model compared to placebo treatment (P < 0.001). All comparisons with the positive-control drug, fluconazole at 50 mg/kg per day, demonstrated either statistical equivalence or superiority of VT-1161. VT-1161 treatment also prevented dissemination of infection from the original inoculation site to a greater extent than fluconazole. Many of these in vivo results can be explained by the long half-life of VT-1161 leading to sustained high plasma levels. Thus, the efficacy and pharmacokinetics of VT-1161 are attractive characteristics for long-term treatment of this serious fungal infection.


Assuntos
Inibidores de 14-alfa Desmetilase/farmacologia , Antifúngicos/farmacologia , Coccidioides/efeitos dos fármacos , Coccidioidomicose/tratamento farmacológico , Fluconazol/farmacologia , Fungemia/prevenção & controle , Piridinas/farmacologia , Tetrazóis/farmacologia , Inibidores de 14-alfa Desmetilase/sangue , Inibidores de 14-alfa Desmetilase/farmacocinética , Animais , Antifúngicos/sangue , Antifúngicos/farmacocinética , Coccidioides/enzimologia , Coccidioides/crescimento & desenvolvimento , Coccidioidomicose/microbiologia , Coccidioidomicose/mortalidade , Coccidioidomicose/patologia , Modelos Animais de Doenças , Feminino , Fluconazol/sangue , Fluconazol/farmacocinética , Proteínas Fúngicas/antagonistas & inibidores , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fungemia/microbiologia , Fungemia/mortalidade , Fungemia/patologia , Meia-Vida , Humanos , Camundongos , Testes de Sensibilidade Microbiana , Piridinas/sangue , Piridinas/farmacocinética , Esterol 14-Desmetilase/genética , Esterol 14-Desmetilase/metabolismo , Análise de Sobrevida , Tetrazóis/sangue , Tetrazóis/farmacocinética , Resultado do Tratamento
20.
Eukaryot Cell ; 14(10): 1043-53, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26275879

RESUMO

Coccidioides immitis and Coccidioides posadasii are soil-dwelling fungi and the causative agents of coccidioidomycosis, a mycosis endemic to certain semiarid regions in the Americas. The most common route of infection is by inhalation of airborne Coccidioides arthroconidia. Once a susceptible host inhales the conidia, a transition to mature endosporulated spherules can occur within the first 5 days of infection. For this study, we examined the host response in a murine model of coccidioidomycosis during a time period of infection that has not been well characterized. We collected lung tissue and bronchoalveolar lavage fluid (BALF) from BALB/c mice that were infected with a C. immitis pure strain, a C. immitis hybrid strain, or a C. posadasii strain as well as uninfected mice. We compared the host responses to the Coccidioides strains used in this study by assessing the level of transcription of selected cytokine genes in lung tissues and characterized host and fungal proteins present in BALF. Host response varied depending on the Coccidioides strain that was used and did not appear to be overly robust. This study provides a foundation to begin to dissect the host immune response early in infection, to detect abundant Coccidioides proteins, and to develop diagnostics that target these early time points of infection.


Assuntos
Coccidioides/imunologia , Coccidioides/isolamento & purificação , Coccidioidomicose/imunologia , Citocinas/genética , Imunidade Inata/imunologia , Animais , Líquido da Lavagem Broncoalveolar/imunologia , Líquido da Lavagem Broncoalveolar/microbiologia , Coccidioides/genética , Coccidioidomicose/microbiologia , Feminino , Pulmão/imunologia , Pulmão/microbiologia , Pulmão/patologia , Camundongos , Camundongos Endogâmicos BALB C , RNA Mensageiro/genética , Esporos Fúngicos/imunologia
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