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1.
Sci Rep ; 9(1): 20064, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31882805

RESUMO

In young patients with acute pulmonary embolism (PE), the predictive value of currently available prognostic tools has not been evaluated. Our objective was to compare prognostic value of 7 available tools (GPS, PESI, sPESI, Prognostic Algorithm, PREP, shock index and RIETE) in patients aged <50 years. We used the RIETE database, including PE patients from 2001 to 2017. The major outcome was 30-day all-cause mortality. Of 34,651 patients with acute PE, 5,822 (17%) were aged <50 years. Of these, 83 (1.4%) died during the first 30 days. Number of patients deemed low risk with tools was: PREP (95.9%), GPS (89.6%), PESI (87.2%), Shock index (70.9%), sPESI (59.4%), Prognostic algorithm (58%) and RIETE score (48.6%). The tools with a highest sensitivity were: Prognostic Algorithm (91.6%; 95% CI: 85.6-97.5), RIETE score (90.4%; 95%CI: 84.0-96.7) and sPESI (88%; 95% CI: 81-95). The RIETE, Prognostic Algorithm and sPESI scores obtained the highest overall sensitivity estimates for also predicting 7- and 90-day all-cause mortality, 30-day PE-related mortality, 30-day major bleeding and 30-day VTE recurrences. The proportion of low-risk patients who died within the first 30 days was lowest using the Prognostic Algorithm (0.2%), RIETE (0.3%) or sPESI (0.3%) scores. In PE patients less 50 years, 30-day mortality was low. Although sPESI, RIETE and Prognostic Algorithm scores were the most sensitive tools to identify patients at low risk to die, other tools should be evaluated in this population to obtain more efficient results.

3.
TH Open ; 2(2): e210-e217, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31249944

RESUMO

Background The natural history of patients with lung cancer and venous thromboembolism (VTE) has not been consistently evaluated. Methods We used the RIETE (Registro Informatizado Enfermedad TromboEmbólica) database to assess the clinical characteristics, time course, and outcomes during anticoagulation of lung cancer patients with acute, symptomatic VTE. Results As of May 2017, a total of 1,725 patients were recruited: 1,208 (70%) presented with pulmonary embolism (PE) and 517 with deep vein thrombosis (DVT). Overall, 865 patients (50%) were diagnosed with cancer <3 months before, 1,270 (74%) had metastases, and 1,250 (72%) had no additional risk factors for VTE. During anticoagulation (median, 93 days), 166 patients had symptomatic VTE recurrences (recurrent DVT: 86, PE: 80), 63 had major bleeding (intracranial 11), and 870 died. The recurrence rate was twofold higher than the major bleeding rate during the first month, and over threefold higher beyond the first month. Fifty-seven patients died of PE and 15 died of bleeding. Most fatal PEs (84%) and most fatal bleeds (67%) occurred within the first month of therapy. Nine patients with fatal PE (16%) died within the first 24 hours. Of 72 patients dying of PE or bleeding, 15 (21%) had no metastases and 29 (40%) had the VTE shortly after surgery or immobility. Conclusion Active surveillance on early signs and/or symptoms of VTE in patients with recently diagnosed lung cancer and prescription of prophylaxis in those undergoing surgery or during periods of immobilization might likely help prevent VTE better, detect it earlier, and treat it more efficiently.

4.
TH Open ; 2(4): e373-e386, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31249964

RESUMO

Despite the growing interest and improved knowledge about venous thromboembolism in cancer patients in the last years, there are still many unsolved issues. Due to the limitations of the available literature, evidence-based clinical practice guidelines are not able to give solid recommendations for challenging scenarios often present in the setting of cancer-associated thrombosis (CAT). A multidisciplinary expert panel from three scientific societies-Spanish Society of Internal Medicine (SEMI), Spanish Society of Medical Oncology (SEOM), and Spanish Society Thrombosis and Haemostasis (SETH)-agreed on 12 controversial questions regarding prevention and management of CAT, which were thoroughly reviewed to provide further guidance. The suggestions presented herein may facilitate clinical decisions in specific complex circumstances, until these can be made leaning on reliable scientific evidence.

5.
JCI Insight ; 2(13)2017 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-28679950

RESUMO

Dengue virus (DENV) is the most prevalent mosquito-borne virus causing human disease. Of the 4 DENV serotypes, epidemiological data suggest that DENV-2 secondary infections are associated with more severe disease than DENV-4 infections. Mass cytometry by time-of-flight (CyTOF) was used to dissect immune changes induced by DENV-2 and DENV-4 in human DCs, the initial targets of primary infections that likely affect infection outcomes. Strikingly, DENV-4 replication peaked earlier and promoted stronger innate immune responses, with increased expression of DC activation and migration markers and increased cytokine production, compared with DENV-2. In addition, infected DCs produced higher levels of inflammatory cytokines compared with bystander DCs, which mainly produced IFN-induced cytokines. These high-dimensional analyses during DENV-2 and DENV-4 infections revealed distinct viral signatures marked by different replication strategies and antiviral innate immune induction in DCs, which may result in different viral fitness, transmission, and pathogenesis.

6.
Biochem Biophys Res Commun ; 492(4): 587-596, 2017 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-28576494

RESUMO

The prompt and tightly controlled induction of type I interferon is a central event of the immune defense against viral infection. Flaviviruses comprise a large family of arthropod-borne positive-stranded RNA viruses, many of which represent a serious threat to global human health due to their high rates of morbidity and mortality. All flaviviruses studied so far have been shown to counteract the host's immune response to establish a productive infection and facilitate viral spread. Here, we review the current knowledge on the main strategies that human pathogenic flaviviruses utilize to escape both type I IFN induction and effector pathways. A better understanding of the specific mechanisms by which flaviviruses activate and evade innate immune responses is critical for the development of better therapeutics and vaccines.


Assuntos
Infecções por Flavivirus/imunologia , Infecções por Flavivirus/virologia , Flavivirus/imunologia , Interações Hospedeiro-Patógeno/imunologia , Imunidade Inata/imunologia , Interferon Tipo I/imunologia , Animais , Humanos , Modelos Imunológicos , Replicação Viral/imunologia
7.
Nat Microbiol ; 2: 17037, 2017 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-28346446

RESUMO

During the last few decades, the global incidence of dengue virus (DENV) has increased dramatically, and it is now endemic in more than 100 countries. To establish a productive infection in humans, DENV uses different strategies to inhibit or avoid the host innate immune system. Several DENV proteins have been shown to strategically target crucial components of the type I interferon system. Here, we report that the DENV NS2B protease cofactor targets the DNA sensor cyclic GMP-AMP synthase (cGAS) for lysosomal degradation to avoid the detection of mitochondrial DNA during infection. Such degradation subsequently results in the inhibition of type I interferon production in the infected cell. Our data demonstrate a mechanism by which cGAS senses cellular damage upon DENV infection.


Assuntos
DNA Mitocondrial/fisiologia , Vírus da Dengue/genética , Interações Hospedeiro-Patógeno , Nucleotidiltransferases/metabolismo , Proteínas não Estruturais Virais/metabolismo , DNA Mitocondrial/genética , Células Dendríticas/virologia , Dengue/imunologia , Dengue/virologia , Vírus da Dengue/química , Vírus da Dengue/enzimologia , Vírus da Dengue/imunologia , Células HEK293 , Humanos , Imunidade Inata , Interferon Tipo I/imunologia , Proteínas de Membrana/metabolismo , Nucleotidiltransferases/deficiência , Nucleotidiltransferases/genética , Nucleotidiltransferases/imunologia , Transdução de Sinais , Proteínas não Estruturais Virais/genética
8.
PLoS Pathog ; 13(3): e1006265, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28264033

RESUMO

The Flavivirus genus includes a large number of medically relevant pathogens that cycle between humans and arthropods. This host alternation imposes a selective pressure on the viral population. Here, we found that dengue virus, the most important viral human pathogen transmitted by insects, evolved a mechanism to differentially regulate the production of viral non-coding RNAs in mosquitos and humans, with a significant impact on viral fitness in each host. Flavivirus infections accumulate non-coding RNAs derived from the viral 3'UTRs (known as sfRNAs), relevant in viral pathogenesis and immune evasion. We found that dengue virus host adaptation leads to the accumulation of different species of sfRNAs in vertebrate and invertebrate cells. This process does not depend on differences in the host machinery; but it was found to be dependent on the selection of specific mutations in the viral 3'UTR. Dissecting the viral population and studying phenotypes of cloned variants, the molecular determinants for the switch in the sfRNA pattern during host change were mapped to a single RNA structure. Point mutations selected in mosquito cells were sufficient to change the pattern of sfRNAs, induce higher type I interferon responses and reduce viral fitness in human cells, explaining the rapid clearance of certain viral variants after host change. In addition, using epidemic and pre-epidemic Zika viruses, similar patterns of sfRNAs were observed in mosquito and human infected cells, but they were different from those observed during dengue virus infections, indicating that distinct selective pressures act on the 3'UTR of these closely related viruses. In summary, we present a novel mechanism by which dengue virus evolved an RNA structure that is under strong selective pressure in the two hosts, as regulator of non-coding RNA accumulation and viral fitness. This work provides new ideas about the impact of host adaptation on the variability and evolution of flavivirus 3'UTRs with possible implications in virulence and viral transmission.


Assuntos
Adaptação Biológica/genética , Culicidae/virologia , Vírus da Dengue/genética , Aptidão Genética/genética , RNA Viral/genética , Regiões 3' não Traduzidas/genética , Animais , Northern Blotting , Dengue/genética , Variação Genética , Genoma Viral , Interações Hospedeiro-Patógeno/genética , Humanos , Insetos Vetores/virologia , Filogenia , Reação em Cadeia da Polimerase , Transfecção
9.
PLoS Pathog ; 13(3): e1006258, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28278235

RESUMO

Zika virus (ZIKV) is a mosquito borne flavivirus, which was a neglected tropical pathogen until it emerged and spread across the Pacific Area and the Americas, causing large human outbreaks associated with fetal abnormalities and neurological disease in adults. The factors that contributed to the emergence, spread and change in pathogenesis of ZIKV are not understood. We previously reported that ZIKV evades cellular antiviral responses by targeting STAT2 for degradation in human cells. In this study, we demonstrate that Stat2-/- mice are highly susceptible to ZIKV infection, recapitulate virus spread to the central nervous system (CNS), gonads and other visceral organs, and display neurological symptoms. Further, we exploit this model to compare ZIKV pathogenesis caused by a panel of ZIKV strains of a range of spatiotemporal history of isolation and representing African and Asian lineages. We observed that African ZIKV strains induce short episodes of severe neurological symptoms followed by lethality. In comparison, Asian strains manifest prolonged signs of neuronal malfunctions, occasionally causing death of the Stat2-/- mice. African ZIKV strains induced higher levels of inflammatory cytokines and markers associated with cellular infiltration in the infected brain in mice, which may explain exacerbated pathogenesis in comparison to those of the Asian lineage. Interestingly, viral RNA levels in different organs did not correlate with the pathogenicity of the different strains. Taken together, we have established a new murine model that supports ZIKV infection and demonstrate its utility in highlighting intrinsic differences in the inflammatory response induced by different ZIKV strains leading to severity of disease. This study paves the way for the future interrogation of strain-specific changes in the ZIKV genome and their contribution to viral pathogenesis.


Assuntos
Modelos Animais de Doenças , Infecção por Zika virus/imunologia , Zika virus/imunologia , Zika virus/patogenicidade , Animais , Inflamação/imunologia , Inflamação/virologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Filogenia , Reação em Cadeia da Polimerase em Tempo Real , Zika virus/genética
10.
JCI Insight ; 2(4): e88226, 2017 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-28239647

RESUMO

HIV-1 viremic controllers (VC) spontaneously control infection without antiretroviral treatment. Several studies indicate that IgG Abs from VCs induce enhanced responses from immune effector cells. Since signaling through Fc-γ receptors (FCGRs) modulate these Ab-driven responses, here we examine if enhanced FCGR activation is a common feature of IgG from VCs. Using an infected cell-based system, we observed that VC IgG stimulated greater FCGR2A and FCGR3A activation as compared with noncontrollers, independent of the magnitude of HIV-specific Ab binding or virus neutralization activities. Multivariate regression analysis showed that enhanced FCGR signaling was a significant predictor of VC status as compared with chronically infected patients (CIP) on highly active antiretroviral therapy (HAART). Unsupervised hierarchical clustering of patient IgG functions primarily grouped VC IgG profiles by enhanced FCGR2A, FCGR3A, or dual signaling activity. Our findings demonstrate that enhanced FCGR signaling is a common and significant predictive feature of VC IgG, with VCs displaying a distinct spectrum of FCGR activation profiles. Thus, profiling FCGR activation may provide a useful method for screening and distinguishing protective anti-HIV IgG responses in HIV-infected patients and in monitoring HIV vaccination regimens.


Assuntos
Infecções por HIV/imunologia , HIV-1/imunologia , Imunoglobulina G/imunologia , Receptores de IgG/imunologia , Viremia/imunologia , Terapia Antirretroviral de Alta Atividade , Resistência à Doença , Feminino , Infecções por HIV/tratamento farmacológico , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Transdução de Sinais
12.
Eur Respir J ; 48(5): 1360-1368, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27660517

RESUMO

Current guidelines suggest treating cancer patients with incidental pulmonary embolism comparably to patients with symptomatic pulmonary embolism.We used the Registro Informatizado de Enfermedad TromboEmbólica (RIETE) registry to compare the rate of major bleeding and symptomatic pulmonary embolism during the course of anticoagulation and after its discontinuation in cancer patients with incidental pulmonary embolism.As of March 2016, 715 cancer patients with incidental pulmonary embolism had been enrolled in RIETE. During the course of anticoagulant therapy (mean 235 days), the rate of major bleeding was higher than the rate of symptomatic pulmonary embolism (10.1 (95% CI 7.48-13.4) versus 3.17 (95% CI 1.80-5.19) events per 100 patient-years, respectively), and the rate of fatal bleeding was higher than the rate of fatal pulmonary embolism (2.66 (95% CI 1.44-4.52) versus 0.66 (95% CI 0.17-1.81) deaths per 100 patient-years, respectively). After discontinuing anticoagulation (mean follow-up 117 days), the rate of major bleeding was lower than the rate of symptomatic pulmonary embolism (3.00 (95% CI 1.10-6.65) versus 8.37 (95% CI 4.76-13.7) events per 100 patient-years, respectively); however, there were no differences in the rate of fatal events at one death each.The risk/benefit ratio of anticoagulant therapy in cancer patients with incidental pulmonary embolism is uncertain and must be evaluated in further studies.


Assuntos
Anticoagulantes/uso terapêutico , Neoplasias/complicações , Neoplasias/tratamento farmacológico , Embolia Pulmonar/complicações , Embolia Pulmonar/tratamento farmacológico , Idoso , Anticoagulantes/efeitos adversos , Feminino , Hemorragia , Humanos , Achados Incidentais , Masculino , Pessoa de Meia-Idade , Embolia Pulmonar/prevenção & controle , Sistema de Registros , Medição de Risco , Terapia Trombolítica , Resultado do Tratamento
15.
Cell Host Microbe ; 18(3): 345-53, 2015 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-26355217

RESUMO

Combination antiretroviral therapy (ART) is able to suppress HIV-1 replication to undetectable levels. However, the persistence of latent viral reservoirs allows for a rebound of viral load upon cessation of therapy. Thus, therapeutic strategies to eradicate the viral latent reservoir are critically needed. Employing a targeted RNAi screen, we identified the ubiquitin ligase BIRC2 (cIAP1), a repressor of the noncanonical NF-κB pathway, as a potent negative regulator of LTR-dependent HIV-1 transcription. Depletion of BIRC2 through treatment with small molecule antagonists known as Smac mimetics enhanced HIV-1 transcription, leading to a reversal of latency in a JLat latency model system. Critically, treatment of resting CD4+ T cells isolated from ART-suppressed patients with the histone deacetylase inhibitor (HDACi) panobinostat together with Smac mimetics resulted in synergistic activation of the latent reservoir. These data implicate Smac mimetics as useful agents for shock-and-kill strategies to eliminate the latent HIV reservoir.


Assuntos
Regulação Viral da Expressão Gênica , HIV-1/fisiologia , Interações Hospedeiro-Patógeno , Proteínas Inibidoras de Apoptose/metabolismo , Transcrição Genética/efeitos dos fármacos , Ubiquitina-Proteína Ligases/metabolismo , Ativação Viral/efeitos dos fármacos , Latência Viral/efeitos dos fármacos , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/virologia , Células Cultivadas , Humanos , Ácidos Hidroxâmicos/metabolismo , Indóis/metabolismo , Proteínas Inibidoras de Apoptose/antagonistas & inibidores , Oligopeptídeos/metabolismo , Panobinostat , Ubiquitina-Proteína Ligases/antagonistas & inibidores
16.
J Virol ; 89(19): 9781-90, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26178989

RESUMO

UNLABELLED: The accessory HIV protein Vpu inhibits a number of cellular pathways that trigger host innate restriction mechanisms. HIV Vpu-mediated degradation of tetherin allows efficient particle release and hampers the activation of the NF-κB pathway thereby limiting the expression of proinflammatory genes. In addition, Vpu reduces cell surface expression of several cellular molecules such as newly synthesized CD4. However, the role of HIV Vpu in regulating the type 1 interferon response to viral infection by degradation of the interferon regulatory factor 3 (IRF3) has been subject of conflicting reports. We therefore systematically investigated the expression of IRF3 in primary CD4(+) T cells and macrophages infected with HIV at different time points. In addition, we also tested the ability of Vpu to interfere with innate immune signaling pathways such as the NF-κB and the IRF3 pathways. We report here that HIV Vpu failed to degrade IRF3 in infected primary cells. Moreover, we observed that HIV NL4.3 Vpu had no effect on IRF3-dependent gene expression in reporter assays. On the other hand, HIV NL4.3 Vpu downmodulated NF-κB-dependent transcription. Mutation of two serines (positions 52 and 56) involved in the binding of NL4.3 Vpu to the ßTrCP ubiquitin ligase abolishes its ability to inhibit NF-κB activity. Taken together, these results suggest that HIV Vpu regulates antiviral innate response in primary human cells by acting specifically on the NF-κB pathway. IMPORTANCE: HIV Vpu plays a pivotal role in enhancing HIV infection by counteraction of Tetherin. However, Vpu also regulates host response to HIV infection by hampering the type 1 interferon response. The molecular mechanism by which Vpu inhibits the interferon response is still controversial. Here we report that Vpu affects interferon expression by inhibiting NF-κB activity without affecting IRF3 levels or activity. These data suggest that Vpu facilitates HIV infection by regulating NF-κB transcription to levels sufficient for viral transcription while limiting cellular responses to infection.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Regulação da Expressão Gênica/imunologia , HIV-1/imunologia , Proteínas do Vírus da Imunodeficiência Humana/metabolismo , NF-kappa B/metabolismo , Transdução de Sinais/imunologia , Proteínas Virais Reguladoras e Acessórias/metabolismo , Linfócitos T CD4-Positivos/virologia , Primers do DNA/genética , Citometria de Fluxo , Proteínas de Fluorescência Verde/metabolismo , Células HEK293 , HIV-1/metabolismo , Humanos , Immunoblotting , Fator Regulador 3 de Interferon/metabolismo , Luciferases , Plasmídeos/genética
17.
Ann Am Thorac Soc ; 12(8): 1122-9, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26114586

RESUMO

RATIONALE: Patients with acute symptomatic pulmonary embolism (PE) deemed to be at low risk for early complications might be candidates for partial or complete outpatient treatment. OBJECTIVES: To develop and validate a clinical prediction rule that accurately identifies patients with PE and low risk of short-term complications and to compare its prognostic ability with two previously validated models (i.e., the Pulmonary Embolism Severity Index [PESI] and the Simplified PESI [sPESI]) METHODS: Multivariable logistic regression of a large international cohort of patients with PE prospectively enrolled in the RIETE (Registro Informatizado de la Enfermedad TromboEmbólica) registry. MEASUREMENTS AND MAIN RESULTS: All-cause mortality, recurrent PE, and major bleeding up to 10 days after PE diagnosis were determined. Of 18,707 eligible patients with acute symptomatic PE, 46 (0.25%) developed recurrent PE, 203 (1.09%) bled, and 471 (2.51%) died. Predictors included in the final model were chronic heart failure, recent immobilization, recent major bleeding, cancer, hypotension, tachycardia, hypoxemia, renal insufficiency, and abnormal platelet count. The area under receiver-operating characteristic curve was 0.77 (95% confidence interval [CI], 0.75-0.78) for the RIETE score, 0.72 (95% CI, 0.70-0.73) for PESI (P < 0.05), and 0.71 (95% CI, 0.69-0.73) for sPESI (P < 0.05). Our RIETE score outperformed the prognostic value of PESI in terms of net reclassification improvement (P < 0.001), integrated discrimination improvement (P < 0.001), and sPESI (net reclassification improvement, P < 0.001; integrated discrimination improvement, P < 0.001). CONCLUSIONS: We built a new score, based on widely available variables, that can be used to identify patients with PE at low risk of short-term complications, assisting in triage and potentially shortening duration of hospital stay.


Assuntos
Anticoagulantes/uso terapêutico , Pacientes Ambulatoriais/estatística & dados numéricos , Embolia Pulmonar/diagnóstico , Embolia Pulmonar/mortalidade , Embolia Pulmonar/terapia , Índice de Gravidade de Doença , Idoso , Idoso de 80 Anos ou mais , Assistência Ambulatorial , Técnicas de Apoio para a Decisão , Feminino , Hemorragia , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Prognóstico , Estudos Prospectivos , Curva ROC , Sistema de Registros , Medição de Risco
18.
Nat Immunol ; 16(5): 485-94, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25822250

RESUMO

The human helicase senataxin (SETX) has been linked to the neurodegenerative diseases amyotrophic lateral sclerosis (ALS4) and ataxia with oculomotor apraxia (AOA2). Here we identified a role for SETX in controlling the antiviral response. Cells that had undergone depletion of SETX and SETX-deficient cells derived from patients with AOA2 had higher expression of antiviral mediators in response to infection than did wild-type cells. Mechanistically, we propose a model whereby SETX attenuates the activity of RNA polymerase II (RNAPII) at genes stimulated after a virus is sensed and thus controls the magnitude of the host response to pathogens and the biogenesis of various RNA viruses (e.g., influenza A virus and West Nile virus). Our data indicate a potentially causal link among inborn errors in SETX, susceptibility to infection and the development of neurologic disorders.


Assuntos
Esclerose Amiotrófica Lateral/genética , Influenza Humana/imunologia , Orthomyxoviridae/fisiologia , RNA Helicases/metabolismo , RNA Polimerase II/metabolismo , Degenerações Espinocerebelares/genética , Febre do Nilo Ocidental/imunologia , Vírus do Nilo Ocidental/fisiologia , Animais , Linhagem Celular Tumoral , Citocinas/metabolismo , Cães , Regulação para Baixo , Humanos , Imunidade Inata/genética , Fator Regulador 3 de Interferon/metabolismo , Células Madin Darby de Rim Canino , Camundongos , Camundongos Knockout , Análise em Microsséries , RNA Helicases/genética , RNA Polimerase II/genética , RNA Interferente Pequeno/genética , Ataxias Espinocerebelares/congênito , Células Vero , Replicação Viral/genética
19.
Immunity ; 40(6): 880-95, 2014 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-24882218

RESUMO

Type I interferons (IFN-I) are essential antiviral cytokines produced upon microbial infection. IFN-I elicits this activity through the upregulation of hundreds of IFN-I-stimulated genes (ISGs). The full breadth of ISG induction demands activation of a number of cellular factors including the IκB kinase epsilon (IKKε). However, the mechanism of IKKε activation upon IFN receptor signaling has remained elusive. Here we show that TRIM6, a member of the E3-ubiquitin ligase tripartite motif (TRIM) family of proteins, interacted with IKKε and promoted induction of IKKε-dependent ISGs. TRIM6 and the E2-ubiquitin conjugase UbE2K cooperated in the synthesis of unanchored K48-linked polyubiquitin chains, which activated IKKε for subsequent STAT1 phosphorylation. Our work attributes a previously unrecognized activating role of K48-linked unanchored polyubiquitin chains in kinase activation and identifies the UbE2K-TRIM6-ubiquitin axis as critical for IFN signaling and antiviral response.


Assuntos
Quinase I-kappa B/imunologia , Interferon Tipo I/imunologia , Poliubiquitina/biossíntese , Ubiquitina-Proteína Ligases/imunologia , Animais , Antivirais , Células Cultivadas , Ativação Enzimática/imunologia , Humanos , Janus Quinase 1 , Camundongos , Fosforilação/imunologia , Interferência de RNA , RNA Interferente Pequeno , Fator de Transcrição STAT1/imunologia , Transdução de Sinais/imunologia , Proteínas com Motivo Tripartido , Enzimas de Conjugação de Ubiquitina/imunologia , Ubiquitina-Proteína Ligases/genética
20.
PLoS One ; 9(2): e89284, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24586659

RESUMO

Innate immune sensors such as Toll-like receptors (TLRs) differentially utilize adaptor proteins and additional molecular mediators to ensure robust and precise immune responses to pathogen challenge. Through a gain-of-function genetic screen, we identified the gamma catalytic subunit of protein phosphatase 1 (PP1-γ) as a positive regulator of MyD88-dependent proinflammatory innate immune activation. PP1-γ physically interacts with the E3 ubiquitin ligase TRAF6, and enhances the activity of TRAF6 towards itself and substrates such as IKKγ, whereas enzymatically inactive PP1-γ represses these events. Importantly, these activities were found to be critical for cellular innate responses to pathogen challenge and microbial clearance in both mouse macrophages and human monocyte lines. These data indicate that PP1-γ phosphatase activity regulates overall TRAF6 E3 ubiquitin ligase function and promotes NF-κB-mediated innate signaling responses.


Assuntos
Células Dendríticas/imunologia , Regulação da Expressão Gênica , Imunidade Inata , Macrófagos/imunologia , Proteína Fosfatase 1/fisiologia , Infecções Estreptocócicas/imunologia , Fator 6 Associado a Receptor de TNF/metabolismo , Animais , Western Blotting , Células Cultivadas , Células Dendríticas/metabolismo , Células Dendríticas/microbiologia , Ensaio de Imunoadsorção Enzimática , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Imunoprecipitação , Macrófagos/metabolismo , Macrófagos/microbiologia , Camundongos , Mutação/genética , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/metabolismo , NF-kappa B/genética , NF-kappa B/metabolismo , RNA Mensageiro/genética , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Infecções Estreptocócicas/metabolismo , Infecções Estreptocócicas/microbiologia , Streptococcus/patogenicidade , Fator 6 Associado a Receptor de TNF/antagonistas & inibidores , Fator 6 Associado a Receptor de TNF/genética , Receptores Toll-Like/genética , Receptores Toll-Like/metabolismo
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