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1.
JGH Open ; 7(8): 537-544, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37649856

RESUMO

Background and Aim: Long-term human albumin (HA) infusions improve survival in cirrhotic patients with diuretic resistant ascites. We aimed to determine whether there is a significant benefit in a more unwell real-world cohort. Methods: This is a single-center retrospective cohort study. Patients received outpatient HA between April 2017 and June 2021. Inclusion criteria were age ≥18 years, cirrhosis with ascites, and received at least 1 month of HA. Patients with significant comorbidities and ongoing alcohol use were not excluded. Outcomes assessed were transjugular intrahepatic portosystemic shunt (TIPS)/transplant-free survival (TTFS), and biochemical and prognostic outcomes. Results: Twenty-four patients were included. Median age was 59.5 years. Seven were female (29.2%). Etiology included were alcohol (50%), non-alcoholic steatohepatitis (16.7%), and viral/alcohol (12.5%). Median model for end-stage liver disease-sodium (MELD-Na) was 18.5, with Child-Pugh scores (CPS) A (4.2%), B (50%), and C (45.8%). Improvements in serum sodium (P = 0.014), albumin (P = 0.003), and CPS (P = 0.017) were observed. Reduction in hospitalizations (P = 0.001), particularly portal hypertensive related admissions was observed (relative risk 0.39; 95% confidence interval [CI] 0.21-0.69, P = 0.003), needed to treat 2.09 (95% CI 1.25-3.67). There was a reduction in total paracentesis requirements (P = 0.005). On multivariate analysis, type 2 diabetes mellitus significantly increased risk of TIPS/transplant/death (hazard ratio 6.16; 95% CI 1.23-30.84, P = 0.027). Median TTFS improved in patients with a change in MELD-Na ≤1 at 1 month: 29.4 months versus 7.7 months (P = 0.011). Conclusion: Outpatient HA infusions decrease portal hypertensive related hospital admissions, improve serum sodium, albumin levels, and CPS. Type 2 diabetes mellitus and change in MELD-Na score help discriminate those likely to benefit most.

2.
GastroHep ; 3(4): 212-228, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34539248

RESUMO

BACKGROUND: The current COVID-19 pandemic, caused by Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2), has drastically impacted societies worldwide. Vaccination against SARS-CoV-2 is expected to play a key role in the management of this pandemic. Inflammatory conditions such as inflammatory bowel disease (IBD) often require chronic immunosuppression, which can influence vaccination decisions. AIM: This review article aims to describe the most commonly available SARS-CoV-2 vaccination vectors globally, assess the potential benefits and concerns of vaccination in the setting of immunosuppression and provide medical practitioners with guidance regarding SARS-CoV-2 vaccination in patients with IBD. METHODS: All published Phase 1/2 and/or Phase 3 and 4 studies of SARS-CoV-2 vaccinations were reviewed. IBD international society position papers, safety registry data and media releases from pharmaceutical companies as well as administrative and medicines regulatory bodies were included. General vaccine evidence and recommendations in immunosuppressed patients were reviewed for context. Society position papers regarding special populations, including immunosuppressed, pregnant and breast-feeding individuals were also evaluated. Literature was critically analysed and summarised. RESULTS: Vaccination against SARS-CoV-2 is supported in all adult, non-pregnant individuals with IBD without contraindication. There is the potential that vaccine efficacy may be reduced in those who are immunosuppressed; however, medical therapies should not be withheld in order to undertake vaccination. SARS-CoV-2 vaccines are safe, but data specific to immunosuppressed patients remain limited. CONCLUSIONS: SARS-CoV-2 vaccination is essential from both an individual patient and community perspective and should be encouraged in patients with IBD. Recommendations must be continually updated as real-world and trial-based evidence emerges.

3.
Hepatology ; 64(6): 1934-1950, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27631819

RESUMO

The interplay between host antiviral immunity and immunopathology during hepatitis E virus (HEV) infection determines important clinical outcomes. We characterized the specificity, functionality, and durability of host T-cell responses against the full-length HEV virus and assessed a novel "Quantiferon" assay for the rapid diagnosis of HEV infection. Eighty-nine volunteers were recruited from Oxford, Truro (UK), and Toulouse (France), including 44 immune-competent patients with acute HEV infection, 18 HEV-exposed immunosuppressed organ-transplant recipients (8 with chronic HEV), and 27 healthy volunteers. A genotype 3a peptide library (616 overlapping peptides spanning open reading frames [ORFs] 1-3) was used in interferon-gamma (IFN-γ) T-cell ELISpot assays. CD4+ /CD8+ T-cell subsets and polyfunctionality were defined using ICCS and SPICE analysis. Quantification of IFN-γ used whole-blood stimulation with recombinant HEV-capsid protein in the QuantiFERON kit. HEV-specific T-cell responses were detected in 41/44 immune-competent HEV exposed volunteers (median magnitude: 397 spot-forming units/106 peripheral blood mononuclear cells), most frequently targeting ORF2. High-magnitude, polyfunctional CD4 and CD8+ T cells were detected during acute disease and maintained to 12 years, but these declined over time, with CD8+ responses becoming more monofunctional. Low-level responses were detectable in immunosuppressed patients. Twenty-three novel HEV CD4+ and CD8+ T-cell targets were mapped predominantly to conserved genomic regions. QuantiFERON testing demonstrated an inverse correlation between IFN-γ production and the time from clinical presentation, providing 100% specificity, and 71% sensitivity (area under the receiver operator characteristic curve of 0.86) for HEV exposure at 0.3 IU/mL. CONCLUSION: Robust HEV-specific T-cell responses generated during acute disease predominantly target ORF2, but decline in magnitude and polyfunctionality over time. Defining HEV T-cell targets will be important for the investigation of HEV-associated autoimmune disease. (Hepatology 2016;64:1934-1950).


Assuntos
Vírus da Hepatite E/imunologia , Hepatite E/imunologia , Hepatite E/virologia , Especificidade do Receptor de Antígeno de Linfócitos T , Linfócitos T/imunologia , Linfócitos T/virologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Hepatite E/sangue , Hepatite E/diagnóstico , Humanos , Interferon gama/sangue , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Adulto Jovem
4.
Vaccines (Basel) ; 4(3)2016 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-27490575

RESUMO

An effective therapeutic vaccine for the treatment of chronic hepatitis C virus (HCV) infection, as an adjunct to newly developed directly-acting antivirals (DAA), or for the prevention of reinfection, would significantly reduce the global burden of disease associated with chronic HCV infection. A recombinant chimpanzee adenoviral (ChAd3) vector and a modified vaccinia Ankara (MVA), encoding the non-structural proteins of HCV (NSmut), used in a heterologous prime/boost regimen induced multi-specific, high-magnitude, durable HCV-specific CD4+ and CD8+ T-cell responses in healthy volunteers, and was more immunogenic than a heterologous Ad regimen. We now assess the immunogenicity of this vaccine regimen in HCV infected patients (including patients with a low viral load suppressed with interferon/ribavirin therapy), determine T-cell cross-reactivity to endogenous virus, and compare immunogenicity with that observed previously in both healthy volunteers and in HCV infected patients vaccinated with the heterologous Ad regimen. Vaccination of HCV infected patients with ChAd3-NSmut/MVA-NSmut was well tolerated. Vaccine-induced HCV-specific T-cell responses were detected in 8/12 patients; however, CD4+ T-cell responses were rarely detected, and the overall magnitude of HCV-specific T-cell responses was markedly reduced when compared to vaccinated healthy volunteers. Furthermore, HCV-specific cells had a distinct partially-functional phenotype (lower expression of activation markers, granzyme B, and TNFα production, weaker in vitro proliferation, and higher Tim3 expression, with comparable Tbet and Eomes expression) compared to healthy volunteers. Robust anti-vector T-cells and antibodies were induced, showing that there is no global defect in immunity. The level of viremia at the time of vaccination did not correlate with the magnitude of the vaccine-induced T-cell response. Full-length, next-generation sequencing of the circulating virus demonstrated that T-cells were only induced by vaccination when there was a sequence mismatch between the autologous virus and the vaccine immunogen. However, these T-cells were not cross-reactive with the endogenous viral variant epitopes. Conversely, when there was complete homology between the immunogen and circulating virus at a given epitope T-cells were not induced. T-cell induction following vaccination had no significant impact on HCV viral load. In vitro T-cell culture experiments identified the presence of T-cells at baseline that could be expanded by vaccination; thus, HCV-specific T-cells may have been expanded from pre-existing low-level memory T-cell populations that had been exposed to HCV antigens during natural infection, explaining the partial T-cell dysfunction. In conclusion, vaccination with ChAd3-NSmut and MVA-NSmut prime/boost, a potent vaccine regimen previously optimized in healthy volunteers was unable to reconstitute HCV-specific T-cell immunity in HCV infected patients. This highlights the major challenge of overcoming T-cell exhaustion in the context of persistent antigen exposure.

5.
Hepatology ; 63(5): 1455-70, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26474390

RESUMO

UNLABELLED: Adenoviral vectors encoding hepatitis C virus (HCV) nonstructural (NS) proteins induce multispecific, high-magnitude, durable CD4(+) and CD8(+) T-cell responses in healthy volunteers. We assessed the capacity of these vaccines to induce functional HCV-specific immune responses and determine T-cell cross-reactivity to endogenous virus in patients with chronic HCV infection. HCV genotype 1-infected patients were vaccinated using heterologous adenoviral vectors (ChAd3-NSmut and Ad6-NSmut) encoding HCV NS proteins in a dose escalation, prime-boost regimen, with and without concomitant pegylated interferon-α/ribavirin therapy. Analysis of immune responses ex vivo used human leukocyte antigen class I pentamers, intracellular cytokine staining, and fine mapping in interferon-γ enzyme-linked immunospot assays. Cross-reactivity of T cells with population and endogenous viral variants was determined following viral sequence analysis. Compared to healthy volunteers, the magnitude of HCV-specific T-cell responses following vaccination was markedly reduced. CD8(+) HCV-specific T-cell responses were detected in 15/24 patients at the highest dose, whereas CD4(+) T-cell responses were rarely detectable. Analysis of the host circulating viral sequence showed that T-cell responses were rarely elicited when there was sequence homology between vaccine immunogen and endogenous virus. In contrast, T cells were induced in the context of genetic mismatch between vaccine immunogen and endogenous virus; however, these commonly failed to recognize circulating epitope variants and had a distinct partially functional phenotype. Vaccination was well tolerated but had no significant effect on HCV viral load. CONCLUSION: Vaccination with potent HCV adenoviral vectored vaccines fails to restore T-cell immunity except where there is genetic mismatch between vaccine immunogen and endogenous virus; this highlights the major challenge of overcoming T-cell exhaustion in the context of persistent antigen exposure with implications for cancer and other persistent infections.


Assuntos
Hepacivirus/imunologia , Hepatite C Crônica/imunologia , Linfócitos T/imunologia , Vacinas contra Hepatite Viral/imunologia , Adenoviridae/genética , Adulto , Idoso , Sequência de Aminoácidos , Epitopos de Linfócito T , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/virologia , Humanos , Interferon-alfa/administração & dosagem , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Polietilenoglicóis/administração & dosagem , Proteínas Recombinantes/administração & dosagem , Riboflavina/administração & dosagem , Vacinação
6.
Sci Transl Med ; 6(261): 261ra153, 2014 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-25378645

RESUMO

A protective vaccine against hepatitis C virus (HCV) remains an unmet clinical need. HCV infects millions of people worldwide and is a leading cause of liver cirrhosis and hepatocellular cancer. Animal challenge experiments, immunogenetics studies, and assessment of host immunity during acute infection highlight the critical role that effective T cell immunity plays in viral control. In this first-in-man study, we have induced antiviral immunity with functional characteristics analogous to those associated with viral control in natural infection, and improved upon a vaccine based on adenoviral vectors alone. We assessed a heterologous prime-boost vaccination strategy based on a replicative defective simian adenoviral vector (ChAd3) and modified vaccinia Ankara (MVA) vector encoding the NS3, NS4, NS5A, and NS5B proteins of HCV genotype 1b. Analysis used single-cell mass cytometry and human leukocyte antigen class I peptide tetramer technology in healthy human volunteers. We show that HCV-specific T cells induced by ChAd3 are optimally boosted with MVA, and generate very high levels of both CD8(+) and CD4(+) HCV-specific T cells targeting multiple HCV antigens. Sustained memory and effector T cell populations are generated, and T cell memory evolved over time with improvement of quality (proliferation and polyfunctionality) after heterologous MVA boost. We have developed an HCV vaccine strategy, with durable, broad, sustained, and balanced T cell responses, characteristic of those associated with viral control, paving the way for the first efficacy studies of a prophylactic HCV vaccine.


Assuntos
Adenoviridae/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Hepacivirus/imunologia , Hepatite C/prevenção & controle , Memória Imunológica , Vacinação/métodos , Vacinas contra Hepatite Viral/administração & dosagem , Vacinas Virais/administração & dosagem , Adenoviridae/genética , Animais , Linfócitos T CD4-Positivos/virologia , Linfócitos T CD8-Positivos/virologia , Proliferação de Células , Células Cultivadas , Inglaterra , ELISPOT , Voluntários Saudáveis , Hepacivirus/genética , Hepacivirus/patogenicidade , Hepatite C/diagnóstico , Hepatite C/imunologia , Hepatite C/virologia , Anticorpos Anti-Hepatite C/sangue , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Testes de Liberação de Interferon-gama , Ativação Linfocitária , Pan troglodytes , Fatores de Tempo , Resultado do Tratamento , Vacinas de DNA , Vacinas contra Hepatite Viral/genética , Vacinas contra Hepatite Viral/imunologia , Vacinas Virais/genética , Vacinas Virais/imunologia
8.
Proc Natl Acad Sci U S A ; 111(14): 5248-53, 2014 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-24706837

RESUMO

Glioblastoma is the most common adult primary brain tumor and has a dismal median survival. Radiation is a mainstay of treatment and significantly improves survival, yet recurrence is nearly inevitable. Better understanding the radiation response of glioblastoma will help improve strategies to treat this devastating disease. Here, we present a comprehensive study of the in vivo radiation response of glioma cells in a mouse model of proneural glioblastoma. These tumors are a heterogeneous mix of cell types with differing radiation sensitivities. To explicitly study the gene expression changes comprising the radiation response of the Olig2(+) tumor bulk cells, we used translating ribosome affinity purification (TRAP) from Olig2-TRAP transgenic mice. Comparing both ribosome-associated and total pools of mRNA isolated from Olig2(+) cells indicated that the in vivo gene expression response to radiation occurs primarily at the total transcript level. Genes related to apoptosis and cell growth were significantly altered. p53 and E2F were implicated as major regulators of the radiation response, with p53 activity needed for the largest gene expression changes after radiation. Additionally, radiation induced a marked shift away from a proneural expression pattern toward a mesenchymal one. This shift occurs in Olig2(+) cells within hours and in multiple genetic backgrounds. Targets for Stat3 and CEBPB, which have been suggested to be master regulators of a mesenchymal shift, were also up-regulated by radiation. These data provide a systematic description of the events following radiation and may be of use in identifying biological processes that promote glioma radioresistance.


Assuntos
Neoplasias Encefálicas/patologia , Glioblastoma/patologia , Mesoderma/metabolismo , Neurônios/metabolismo , Tolerância a Radiação/genética , Transcrição Gênica , Proteína Supressora de Tumor p53/fisiologia , Animais , Animais Recém-Nascidos , Fatores de Transcrição E2F/fisiologia , Mesoderma/citologia , Camundongos , Camundongos Transgênicos , Neurônios/citologia , RNA Mensageiro/genética , Proteína Supressora de Tumor p53/genética
9.
Cell Stem Cell ; 14(3): 357-69, 2014 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-24607407

RESUMO

Stem-like glioma cells reside within a perivascular niche and display hallmark radiation resistance. An understanding of the mechanisms underlying these properties will be vital for the development of effective therapies. Here, we show that the stem cell marker CD44 promotes cancer stem cell phenotypes and radiation resistance. In a mouse model of glioma, Cd44(-/-) and Cd44(+/-) animals showed improved survival compared to controls. The CD44 ligand osteopontin shared a perivascular expression pattern with CD44 and promoted glioma stem cell-like phenotypes. These effects were mediated via the γ-secretase-regulated intracellular domain of CD44, which promoted aggressive glioma growth in vivo and stem cell-like phenotypes via CBP/p300-dependent enhancement of HIF-2α activity. In human glioblastoma multiforme, expression of CD44 correlated with hypoxia-induced gene signatures and poor survival. Altogether, these data suggest that in the glioma perivascular niche, osteopontin promotes stem cell-like properties and radiation resistance in adjacent tumor cells via activation of CD44 signaling.


Assuntos
Neoplasias Encefálicas/patologia , Glioblastoma/patologia , Receptores de Hialuronatos/metabolismo , Células-Tronco Neoplásicas/patologia , Osteopontina/metabolismo , Transdução de Sinais , Nicho de Células-Tronco , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Neoplasias Encefálicas/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Proteína p300 Associada a E1A/metabolismo , Glioblastoma/metabolismo , Humanos , Receptores de Hialuronatos/química , Ligantes , Camundongos , Invasividade Neoplásica , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Fenótipo , Fator de Crescimento Derivado de Plaquetas/farmacologia , Estrutura Terciária de Proteína , Transdução de Sinais/efeitos dos fármacos , Nicho de Células-Tronco/efeitos dos fármacos , Análise de Sobrevida
10.
J Gen Virol ; 94(Pt 6): 1259-1265, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23486666

RESUMO

IL28B host genetic make-up is known to play a critical role in the outcome of genotype 1 hepatitis C virus (HCV) infection in the context of both primary infection and therapy. However, the role of IL28B in subtype 3a infection remains unclear, and has not yet been assessed in the UK population where subtype 3a is dominant. In this study, we evaluated the role of the IL28B single-nucleotide polymorphism rs8099917 in 201 patients recruited from two well-defined cohorts (from Nottingham and Oxford), treated with the standard-of-care therapy of pegylated interferon and ribavirin for 24 weeks. We showed that the 'favourable' IL28B gene was associated with a rapid virological response to therapy at 4 weeks (P<0.0001), but not with a sustained virological response to therapy. The median viral load at baseline, before therapy, was markedly increased in people with the 'favourable' IL28B genotype [median viral load for the TT allele, 925,961 IU ml(-1) (range 2200-21,116,965 IU ml(-1)), and for the GT or GG allele, 260,284 IU ml(-1) (range 740-7,560,000 IU ml(-1)); P = 0.0010]. Our results suggest that the host genetic response plays an important role in early viral clearance of subtype 3a virus from the blood. However, significant reservoirs of infection must persist, as viral relapse is common, even in those with the favourable host genotype.


Assuntos
Antivirais/uso terapêutico , Predisposição Genética para Doença , Hepacivirus/fisiologia , Hepatite C/tratamento farmacológico , Hepatite C/genética , Interleucinas/genética , Polimorfismo de Nucleotídeo Único , Carga Viral , Adulto , Idoso , Estudos de Coortes , Feminino , Genótipo , Hepacivirus/efeitos dos fármacos , Hepacivirus/genética , Hepatite C/virologia , Humanos , Interferons/uso terapêutico , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Ribavirina/uso terapêutico , Reino Unido , Adulto Jovem
11.
Brain Pathol ; 23(5): 515-24, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23324039

RESUMO

We report 10 cases of a non-neurocytic, purely neuronal tumor affecting adults. Situated in the cerebral hemispheres, with 7 of 10 confined to the temporal lobes, most presented with seizures as their principal clinical manifestations. On magnetic resosnance imaging (MRI), the tumors generally appeared solid and non-contrast enhancing with minimal diffuse infiltration, edema, or mass effect. Six examples demonstrated internal nodularity. Microscopically, the tumor cells were largely distributed into discrete and coalescent nodules exhibiting varying degrees of matrix vacuolization, principally within the deep cortical ribbon and superficial subcortical white matter. Populating elements ranged from morphologically ambiguous to recognizably neuronal, with only two cases manifesting overt ganglion cell cytology. In all cases, tumor cells exhibited widespread nuclear immunolabeling for the HuC/HuD neuronal antigens, although expression of other neuronal markers, including synaptophysin, neurofilament and chromogranin was variable to absent. Tumor cells also failed to express GFAP, p53, IDH1 R132H, or CD34, although CD34-labeling ramified neural elements were present in the adjoining cortex of seven cases. Molecular analysis in a subset of cases failed to reveal DNA copy number abnormalities or BRAF V600E mutation. Follow-up data indicate that this unusual neuronal lesion behaves in benign, World Health Organization (WHO) grade I fashion and is amenable to surgical control.


Assuntos
Neoplasias Encefálicas/complicações , Neoplasias Encefálicas/patologia , Cérebro/patologia , Convulsões/etiologia , Adulto , Antígenos CD34/metabolismo , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/cirurgia , Feminino , Seguimentos , Genótipo , Humanos , MAP Quinase Quinase 1/genética , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Mutação/genética , Proteínas do Tecido Nervoso/metabolismo , Proteínas Proto-Oncogênicas B-raf/genética , Tomógrafos Computadorizados
12.
J Hepatol ; 58(2): 329-34, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23085647

RESUMO

BACKGROUND & AIMS: Normalization of serum alkaline phosphatase (SAP) was recently shown to correlate with better prognosis in Primary Sclerosing Cholangitis (PSC). We aimed at evaluating the impact of SAP improvement to below 1.5 the upper limit of normal (ULN) on the prognosis of this cholestatic liver disease. METHODS: Oxford PSC database was screened for cases diagnosed between 1980 and 2004. Cases which met the inclusion criteria were retrospectively examined for clinical parameters, laboratory values, and clinical end points (liver decompensation, liver transplantation, and liver-related deaths including cholangiocarcinoma). Cases were followed-up to 31/12/2010. RESULTS: 139 patients were included, (87 males). Improvement of SAP to below 1.5 ULN was achieved by 55 (40%) patients in a median time of 2 years, compared to 84 (60%) who did not. 3/55 (6%) patients with SAP improvement reached an end point compared to 32/84 (38%) patients with no SAP improvement (p <0.0001). 13/84 (15%) patients with no SAP improvement developed cholangiocarcinoma compared to no cholangiocarcinoma in the group with SAP improvement (p = 0.002). The end point free survival was significantly longer in patients with SAP improvement (p <0.0001). The significance of SAP improvement as a predictor of prognosis persisted after controlling for other clinical and laboratory variables. Improvement of SAP to below 1.5 ULN was comparable to complete normalization of SAP in terms of prognosis. CONCLUSIONS: Improvement in SAP to below 1.5 ULN is associated with better outcome and reduced risk of CCA in PSC. This was comparable to the achievement of complete normalization of SAP.


Assuntos
Fosfatase Alcalina/sangue , Neoplasias dos Ductos Biliares/epidemiologia , Ductos Biliares Intra-Hepáticos , Colangiocarcinoma/epidemiologia , Colangite Esclerosante/complicações , Adulto , Biomarcadores/sangue , Colangite Esclerosante/diagnóstico , Colangite Esclerosante/mortalidade , Feminino , Seguimentos , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Fatores de Risco
13.
PLoS One ; 7(10): e46965, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23056544

RESUMO

Post-transcriptional regulation of gene expression contributes to the protein output of a cell, however, methods for measuring translational regulation in complex in vivo systems are lacking. Here, we describe a sensitive method for measuring translational regulation in defined cell populations from heterogeneous tissue in vivo. We adapted the translating ribosome affinity purification (TRAP) methodology to measure the relative occupancy of individual mRNA transcripts in translating ribosomes in the Olig2-positive tumor cell population in a genetically engineered mouse model (GEM) of glioma. Global measurement of paired ribosome-bound and total cellular mRNA populations from tumor cells in vivo identified a broad distribution of relative ribosome occupancies amongst mRNA species that was highly reproducible across biological samples. Comparison of the translation state of glioma cells to non-transformed oligodendrocyte progenitor cells in normal brain identified global alteration of translation in tumor, and specifically of genes involved in cell division and synthetic metabolism. Furthermore, investigation of alteration in steady state translational efficiencies upon loss of PTEN, one of the most frequently mutated and deleted tumor suppressors in glioma, identified differential translation of proteins involved in cellular respiration, canonically regulated by PI3K/Akt signaling, and cellular glycosylation profiles, deregulation of which is known to be associated with tumor progression. Application of the translation efficiency profiling method described here to other biological contexts and conditions would extend our knowledge of the scope and impact of this important mode of gene regulation in complex in vivo systems.


Assuntos
Perfilação da Expressão Gênica , Glioma/genética , Biossíntese de Proteínas/genética , Animais , Respiração Celular/genética , Transformação Celular Neoplásica/genética , Feminino , Deleção de Genes , Glioma/metabolismo , Glioma/patologia , Masculino , Camundongos , PTEN Fosfo-Hidrolase/deficiência , PTEN Fosfo-Hidrolase/genética , Fosfatidilinositol 3-Quinases/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Ribossômico/genética , Transdução de Sinais/genética
14.
Biomark Med ; 6(2): 177-86, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22448791

RESUMO

IFN-γ release by antigen-specific T cells can be used to track immune responses to infections and vaccines. In recent years, there have been substantial advances in the techniques available to measure IFN-γ release and a generation of such assays are now available for clinical use, as well as in a research setting. Interferon release leads to subsequent release of interferon-responsive chemokines such as MIG and IP-10, thus amplifying the original signal. A number of investigators have assessed whether measurement of these chemokines might provide a sensitive platform for detection of infection and antigen-specific T-cell responses. In this article, we assess the potential of these new approaches. We have termed the new antigen-specific T-cell assays monokine-amplified IFN-γ release assays (MIGRAs). Overall, it seems likely that improvements in the detection threshold could be made by analysis of antigen-triggered chemokines and potentially of other molecules in the future, although whether MIGRAs will provide additional clinical utility still remains to be determined.


Assuntos
Testes Diagnósticos de Rotina/métodos , Interferon gama/genética , Monocinas/genética , Reação em Cadeia da Polimerase/métodos , Tuberculose/diagnóstico , Animais , Humanos , Interferon gama/análise , Interferon gama/imunologia , Monocinas/análise , Monocinas/imunologia , Mycobacterium tuberculosis/imunologia , Mycobacterium tuberculosis/fisiologia , Tuberculose/genética , Tuberculose/imunologia , Tuberculose/microbiologia
17.
Expert Rev Vaccines ; 10(5): 659-72, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21604986

RESUMO

Hepatitis C virus (HCV) infects more than 170 million people globally and is a leading cause of liver cirrhosis, transplantation and hepatocellular carcinoma. Current gold-standard therapy often fails, has significant side effects in many cases and is expensive. No vaccine is currently available. The fact that a significant proportion of infected people spontaneously control HCV infection in the setting of an appropriate immune response suggests that a vaccine for HCV is a realistic goal. A comparative analysis of infected people with distinct clinical outcomes has enabled the characterization of many important innate and adaptive immune processes associated with viral control. It is clear that a successful HCV vaccine will need to exploit and enhance these natural immune defense mechanisms. New HCV vaccine approaches, including peptide, recombinant protein, DNA and vector-based vaccines, have recently reached Phase I/II human clinical trials. Some of these technologies have generated robust antiviral immunity in healthy volunteers and infected patients. The challenge now is to move forward into larger at-risk or infected populations to truly test efficacy.


Assuntos
Hepacivirus/imunologia , Hepatite C/prevenção & controle , Vacinas Virais/imunologia , Ensaios Clínicos Fase I como Assunto , Ensaios Clínicos Fase II como Assunto , Hepatite C/epidemiologia , Hepatite C/imunologia , Humanos , Vacinação/métodos
18.
J Biol Chem ; 285(46): 36225-34, 2010 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-20843810

RESUMO

ATP-binding cassette (ABC) transporters are integral membrane proteins that couple ATP binding/hydrolysis with the transport of hydrophilic substrates across lipid barriers. Deletion of Phe-670 in the first nucleotide-binding domain (NBD1) of the yeast ABC transporter, Yor1p, perturbs interdomain associations, reduces functionality, and hinders proper transport to the plasma membrane. Functionality of Yor1p-ΔF was restored upon co-expression of a peptide containing wild-type NBD1. To gain insight into the biogenesis of this important class of proteins, we defined the requirements for this rescue. We show that a misfolding lesion in NBD1 of the full-length protein is a prerequisite for functional rescue by exogenous NBD1, which is mediated by physical replacement of the dysfunctional domain by the soluble NBD1. This association does not restore trafficking of Yor1p-ΔF but instead confers catalytic activity to the small population of Yor1p-ΔF that escapes to the plasma membrane. An important coupling between the exogenous NBD1 and ICL4 within full-length aberrant Yor1p-ΔF is required for functional rescue but not for the physical interaction between the two polypeptides. Together, our genetic and biochemical data reveal that it is possible to modulate activity of ABC transporters by physically replacing dysfunctional domains.


Assuntos
Transportadores de Cassetes de Ligação de ATP/química , Transportadores de Cassetes de Ligação de ATP/metabolismo , Membrana Celular/metabolismo , Dobramento de Proteína , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Sítios de Ligação/genética , Retículo Endoplasmático/metabolismo , Células Eucarióticas/metabolismo , Teste de Complementação Genética/métodos , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Immunoblotting , Microscopia Confocal , Mutação , Transporte Proteico , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Deleção de Sequência
19.
J Biol Chem ; 285(47): 36304-14, 2010 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-20837481

RESUMO

ATP-binding cassette (ABC) transporters play pivotal physiological roles in substrate transport across membranes, and defective assembly of these proteins can cause severe disease associated with improper drug or ion flux. The yeast protein Yor1p is a useful model to study the biogenesis of ABC transporters; deletion of a phenylalanine residue in the first nucleotide-binding domain (NBD1) causes misassembly and retention in the endoplasmic reticulum (ER) of the resulting protein Yor1p-ΔF670, similar to the predominant disease-causing allele in humans, CFTR-ΔF508. Here we describe two novel Yor1p mutants, G278R and I1084P, which fail to assemble and traffic similar to Yor1p-ΔF670. These mutations are located in the two intracellular loops (ICLs) that interface directly with NBD1, and thus disrupt a functionally important structural module. We isolated 2 second-site mutations, F270S and R1168M, which partially correct the folding injuries associated with the G278R, I1084P, and ΔF670 mutants and reinstate their trafficking. The position of both corrective mutations at the cytoplasmic face of a transmembrane helix suggests that they restore biogenesis by influencing the behavior of the transmembrane domains rather than by direct restoration of the ICL1-ICL4-NBD1 structural module. Given the conserved topology of many ABC transporters, our findings provide new understanding of functionally important inter-domain interactions and suggest new potential avenues for correcting folding defects caused by abrogation of those domain interfaces.


Assuntos
Transportadores de Cassetes de Ligação de ATP/química , Transportadores de Cassetes de Ligação de ATP/genética , Dobramento de Proteína , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Supressão Genética/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Transporte Biológico , Regulador de Condutância Transmembrana em Fibrose Cística/química , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Citoplasma/metabolismo , Retículo Endoplasmático/metabolismo , Humanos , Estrutura Terciária de Proteína , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo
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