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1.
Adv Healthc Mater ; : e2303995, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38469995

RESUMO

Rheumatoid arthritis (RA) causes immunological and metabolic imbalances in tissue, exacerbating inflammation in affected joints. Changes in immunological and metabolic tissue homeostasis at different stages of RA are not well understood. Herein, the changes in the immunological and metabolic profiles in different stages in collagen induced arthritis (CIA), namely, early, intermediate, and late stage is examined. Moreover, the efficacy of the inverse-vaccine, paKG(PFK15+bc2) microparticle, to restore tissue homeostasis at different stages is also investigated. Immunological analyses of inverse-vaccine-treated group revealed a significant decrease in the activation of pro-inflammatory immune cells and remarkable increase in regulatory T-cell populations in the intermediate and late stages compared to no treatment. Also, glycolysis in the spleen is normalized in the late stages of CIA in inverse-vaccine-treated mice, which is similar to no-disease tissues. Metabolomics analyses revealed that metabolites UDP-glucuronic acid and L-Glutathione oxidized are significantly altered between treatment groups, and thus might provide new druggable targets for RA treatment. Flux metabolic modeling identified amino acid and carnitine pathways as the central pathways affected in arthritic tissue with CIA progression. Overall, this study shows that the inverse-vaccines initiate early re-establishment of homeostasis, which persists through the disease span.

2.
Nat Commun ; 14(1): 5333, 2023 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-37660049

RESUMO

Inhibition of glycolysis in immune cells and cancer cells diminishes their activity, and thus combining immunotherapies with glycolytic inhibitors is challenging. Herein, a strategy is presented where glycolysis is inhibited in cancer cells using PFK15 (inhibitor of PFKFB3, rate-limiting step in glycolysis), while simultaneously glycolysis and function is rescued in DCs by delivery of fructose-1,6-biphosphate (F16BP, one-step downstream of PFKFB3). To demonstrate the feasibility of this strategy, vaccine formulations are generated using calcium-phosphate chemistry, that incorporate F16BP, poly(IC) as adjuvant, and phosphorylated-TRP2 peptide antigen and tested in challenging and established YUMM1.1 tumours in immunocompetent female mice. Furthermore, to test the versatility of this strategy, adoptive DC therapy is developed with formulations that incorporate F16BP, poly(IC) as adjuvant and mRNA derived from B16F10 cells as antigens in established B16F10 tumours in immunocompetent female mice. F16BP vaccine formulations rescue DCs in vitro and in vivo, significantly improve the survival of mice, and generate cytotoxic T cell (Tc) responses by elevating Tc1 and Tc17 cells within the tumour. Overall, these results demonstrate that rescuing glycolysis of DCs using metabolite-based formulations can be utilized to generate immunotherapy even in the presence of glycolytic inhibitor.


Assuntos
Imunoterapia , Neoplasias , Feminino , Animais , Camundongos , Glicólise , Adjuvantes Imunológicos/farmacologia , Frutose , Poli I-C , Células Dendríticas
3.
Cancers (Basel) ; 14(2)2022 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-35053501

RESUMO

Cancers that metastasize to the lungs represent a major challenge in both basic and clinical cancer research. Oncolytic viruses are newly emerging options but successful delivery and choice of appropriate therapeutic armings are two critical issues. Using an immunocompetent murine K7M2-luc lung metastases model, the efficacy of MYXV armed with murine LIGHT (TNFSF14/CD258) expressed under virus-specific early/late promoter was tested in an advanced later-stage disease K7M2-luc model. Results in this model show that mLIGHT-armed MYXV, delivered systemically using ex vivo pre-loaded PBMCs as carrier cells, reduced tumor burden and increased median survival time. In vitro, when comparing direct infection of K7M2-luc cancer cells with free MYXV vs. PBMC-loaded virus, vMyx-mLIGHT/PBMCs also demonstrated greater cytotoxic capacity against the K7M2 cancer cell targets. In vivo, systemically delivered vMyx-mLIGHT/PBMCs increased viral reporter transgene expression levels both in the periphery and in lung tumors compared to unarmed MYXV, in a tumor- and transgene-dependent fashion. We conclude that vMyx-mLIGHT, especially when delivered using PBMC carrier cells, represents a new potential therapeutic strategy for solid cancers that metastasize to the lung.

4.
Mol Ther Oncolytics ; 22: 539-554, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34553039

RESUMO

Solid cancers that metastasize to the lungs represent a major therapeutic challenge. Current treatment paradigms for lung metastases consist of radiation therapy, chemotherapies, and surgical resection, but there is no single treatment or combination that is effective for all tumor types. To address this, oncolytic myxoma virus (MYXV) engineered to express human tumor necrosis factor (vMyx-hTNF) was tested after systemic administration in an immunocompetent mouse K7M2-Luc lung metastatic osteosarcoma model. Virus therapy efficacy against pre-seeded lung metastases was assessed after systemic infusion of either naked virus or ex vivo-loaded autologous bone marrow leukocytes or peripheral blood mononuclear cells (PBMCs). Results of this study showed that the PBMC pre-loaded strategy was the most effective at reducing tumor burden and increasing median survival time, but sequential intravenous multi-dosing with naked virus was comparably effective to a single infusion of PBMC-loaded virus. PBMC-loaded vMyx-hTNF also potentially synergized very effectively with immune checkpoint inhibitors anti-PD-1, anti-PD-L1, and anti-cytotoxic T lymphocyte associated protein 4 (CTLA-4). Finally, in addition to the pro-immune stimulation caused by unarmed MYXV, the TNF transgene of vMyx-hTNF further induced the unique expression of numerous additional cytokines associated with the innate and adaptive immune responses in this model. We conclude that systemic ex vivo virotherapy with TNF-α-armed MYXV represents a new potential strategy against lung metastatic cancers like osteosarcoma and can potentially act synergistically with established checkpoint immunotherapies.

5.
Mol Ther Oncolytics ; 18: 171-188, 2020 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-32695875

RESUMO

Multiple myeloma (MM) is a hematological malignancy of monoclonal plasma cells that remains incurable. Standard treatments for MM include myeloablative regimens and autologous cell transplantation for eligible patients. A major challenge of these treatments is the relapse of the disease due to residual MM in niches that become refractory to treatments. Therefore, novel therapies are needed in order to eliminate minimal residual disease (MRD). Recently, our laboratory reported that virotherapy with oncolytic myxoma virus (MYXV) improved MM-free survival in an allogeneic transplant mouse model. In this study, we demonstrate the capacity of donor autologous murine leukocytes, pre-armed with MYXV, to eliminate MRD in a BALB/c MM model. We report that MYXV-armed bone marrow (BM) carrier leukocytes are therapeutically superior to MYXV-armed peripheral blood mononuclear cells (PBMCs) or free virus. Importantly, when cured survivor mice were re-challenged with fresh myeloma cells, they developed immunity to the same MM that had comprised MRD. In vivo imaging demonstrated that autologous carrier cells armed with MYXV were very efficient at delivery of MYXV into the recipient tumor microenvironment. Finally, we demonstrate that treatment with MYXV activates the secretion of pro-immune molecules from the tumor bed. These results highlight the utility of exploiting autologous leukocytes to enhance tumor delivery of MYXV to treat MRD in vivo.

6.
J Perianesth Nurs ; 34(2): 330-337, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30033001

RESUMO

PURPOSE: To evaluate the agreement of temporal artery temperature (Tat) with esophageal temperature (Tes) and oral temperature (Tor), and explore potential factors associated with the level of agreement between the thermometry methods in different clinical settings. DESIGN: A prospective repeated measures (induction, emergence, and postanesthesia care unit) design was used. METHODS: Temperature data were collected for 54 patients receiving general anesthesia. Analyses included descriptive statistics, paired t tests for the within-patient comparison of temperature methods, Bland-Altman plots to examine agreement between methods, and multiple linear regression to identify factors associated with the agreement between methods. FINDINGS: Tat was significantly higher compared with Tes and Tor (P < .05) and was poor at detecting hypothermia. The use of a muscle relaxant and surgical site were suggested to be associated with the difference between Tat and Tes at emergence. CONCLUSIONS: Tat is more convenient, but less accurate, than other thermometry methods. These inaccuracies are exacerbated by common anesthetic medications.


Assuntos
Anestesia Geral , Temperatura Corporal/fisiologia , Artérias Temporais/fisiologia , Termometria/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Esôfago/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Boca/fisiologia , Estudos Prospectivos , Termômetros , Adulto Jovem
7.
Immunotherapy ; 8(10): 1233-44, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27605071

RESUMO

Survival outcomes for osteosarcoma have plateaued since the 1980s, and patients with relapsed or refractory disease have a particularly dismal outcome. Treatment options for these patients are limited primarily due to the paucity of effective therapeutics. Immune therapies such as tumor vaccines and traditional antigen-targeted monoclonal antibodies have had limited success in solid tumors. The recent discovery of novel immune checkpoint blockade strategies and their success in adult cancers has revitalized the use of immunotherapy strategies for the treatment of solid tumors. This paper summarizes existing data supporting the use of immune therapies in osteosarcoma and the progress of this class of drugs in osteosarcoma therapy.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Neoplasias Ósseas/terapia , Vacinas Anticâncer/imunologia , Imunoterapia/métodos , Osteossarcoma/terapia , Adulto , Neoplasias Ósseas/imunologia , Neoplasias Ósseas/mortalidade , Receptores Coestimuladores e Inibidores de Linfócitos T/imunologia , Humanos , Glicoproteínas de Membrana/imunologia , Osteossarcoma/imunologia , Osteossarcoma/mortalidade , Análise de Sobrevida
8.
Methods Mol Biol ; 742: 249-64, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21547737

RESUMO

As several genomes have been sequenced, post-genomic approaches like transcriptomics and proteomics, identifying gene products differentially expressed in association with a given pathology, have held promise both of understanding the pathways associated with the respective disease and as a fast track to therapy. Notwithstanding, these approaches cannot distinguish genes and proteins with mere secondary pathological association from those primarily involved in the basic defect(s). New global strategies and tools identifying gene products responsible for the basic cellular defect(s) in CF pathophysiology currently being performed are presented here. These include high-content screens to determine proteins affecting function and trafficking of CFTR and ENaC.


Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística , Fibrose Cística/metabolismo , Canais Epiteliais de Sódio , Genômica/métodos , Linhagem Celular Tumoral , Fibrose Cística/genética , Fibrose Cística/fisiopatologia , Regulador de Condutância Transmembrana em Fibrose Cística/antagonistas & inibidores , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Bloqueadores do Canal de Sódio Epitelial , Canais Epiteliais de Sódio/genética , Canais Epiteliais de Sódio/metabolismo , Fluorescência , Inativação Gênica , Ensaios de Triagem em Larga Escala , Humanos , Microscopia Confocal , Mutação , Plasmídeos/metabolismo , Transporte Proteico , RNA Interferente Pequeno/metabolismo , Deleção de Sequência , Espectrometria de Fluorescência , Transfecção
9.
PLoS Pathog ; 5(6): e1000475, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19521536

RESUMO

With the advent of subgenomic hepatitis C virus (HCV) replicons, studies of the intracellular steps of the viral replication cycle became possible. These RNAs are capable of self-amplification in cultured human hepatoma cells, but save for the genotype 2a isolate JFH-1, efficient replication of these HCV RNAs requires replication enhancing mutations (REMs), previously also called cell culture adaptive mutations. These mutations cluster primarily in the central region of non-structural protein 5A (NS5A), but may also reside in the NS3 helicase domain or at a distinct position in NS4B. Most efficient replication has been achieved by combining REMs residing in NS3 with distinct REMs located in NS4B or NS5A. However, in spite of efficient replication of HCV genomes containing such mutations, they do not support production of infectious virus particles. By using the genotype 1b isolate Con1, in this study we show that REMs interfere with HCV assembly. Strongest impairment of virus formation was found with REMs located in the NS3 helicase (E1202G and T1280I) as well as NS5A (S2204R), whereas a highly adaptive REM in NS4B still allowed virus production although relative levels of core release were also reduced. We also show that cells transfected with the Con1 wild type genome or the genome containing the REM in NS4B release HCV particles that are infectious both in cell culture and in vivo. Our data provide an explanation for the in vitro and in vivo attenuation of cell culture adapted HCV genomes and may open new avenues for the development of fully competent culture systems covering the therapeutically most relevant HCV genotypes.


Assuntos
Hepacivirus/genética , Hepacivirus/fisiologia , Mutação , Vírion/fisiologia , Replicação Viral/fisiologia , Linhagem Celular , Ensaio de Imunoadsorção Enzimática , Antígenos da Hepatite C/genética , Antígenos da Hepatite C/metabolismo , Humanos , Proteínas do Core Viral/genética , Proteínas do Core Viral/metabolismo , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismo , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo , Vírion/química , Vírion/patogenicidade , Cultura de Vírus
10.
J Biol Chem ; 283(42): 28546-62, 2008 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-18644781

RESUMO

The hepatitis C virus (HCV) is a flavivirus replicating in the cytoplasm of infected cells. The HCV genome is a single-stranded RNA encoding a polyprotein that is cleaved by cellular and viral proteases into 10 different products. While the structural proteins core protein, envelope protein 1 (E1) and E2 build up the virus particle, most nonstructural (NS) proteins are required for RNA replication. One of the least studied proteins is NS2, which is composed of a C-terminal cytosolic protease domain and a highly hydrophobic N-terminal domain. It is assumed that the latter is composed of three trans-membrane segments (TMS) that tightly attach NS2 to intracellular membranes. Taking advantage of a system to study HCV assembly in a hepatoma cell line, in this study we performed a detailed characterization of NS2 with respect to its role for virus particle assembly. In agreement with an earlier report ( Jones, C. T., Murray, C. L., Eastman, D. K., Tassello, J., and Rice, C. M. (2007) J. Virol. 81, 8374-8383 ), we demonstrate that the protease domain, but not its enzymatic activity, is required for infectious virus production. We also show that serine residue 168 in NS2, implicated in the phosphorylation and stability of this protein, is dispensable for virion formation. In addition, we determined the NMR structure of the first TMS of NS2 and show that the N-terminal segment (amino acids 3-11) forms a putative flexible helical element connected to a stable alpha-helix (amino acids 12-21) that includes an absolutely conserved helix side in genotype 1b. By using this structure as well as the amino acid conservation as a guide for a functional study, we determined the contribution of individual amino acid residues in TMS1 for HCV assembly. We identified several residues that are critical for virion formation, most notably a central glycine residue at position 10 of TMS1. Finally, we demonstrate that mutations in NS2 blocking HCV assembly can be rescued by trans-complementation.


Assuntos
Hepacivirus/metabolismo , Proteínas não Estruturais Virais/química , Trifosfato de Adenosina/química , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Clonagem Molecular , Humanos , Espectroscopia de Ressonância Magnética , Modelos Biológicos , Conformação Molecular , Mutação , Fosforilação , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Relação Estrutura-Atividade , Proteínas não Estruturais Virais/fisiologia
11.
Ann Clin Psychiatry ; 20(3): 139-44, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18633740

RESUMO

BACKGROUND: Tardive dyskinesia is a serious adverse event, which is associated mainly with the use of the first-generation antipsychotic agents. Convergent data from clinical trials suggest that second-generation antipsychotic agents are less likely to cause tardive dyskinesia. However, the data with regard to the effect of switching from first- to second-generation antipsychotic agents on pre-existing dyskinetic symptoms during routine clinical care is sparse. METHODS: Sixty-three patients with DSM-IV schizophrenia or schizoaffective disorder (n = 61) or bipolar I disorder (n = 2) consecutively admitted to a state hospital, who were treated either with olanzapine (n = 35) or conventional antipsychotic agents (n = 28) by physician choice, were enrolled in the study. The severity and frequency of tardive dyskinetic symptoms using the Abnormal Involuntary Movement Scale were assessed in the two medication groups at baseline, 8 weeks, and 6 months. RESULTS: There were statistically significant reductions in the prevalence and severity of dyskinetic symptoms at 8 weeks and 6 months for the group treated with olanzapine but not for those treated with conventional agents. CONCLUSIONS: These preliminary data suggest that olanzapine may be a treatment option for subjects with tardive dyskinesia. However, the question whether olanzapine treats, ameliorates, or masks preexisting tardive dyskinesia was difficult to answer, as no dosage reduction or withdrawal was undertaken.


Assuntos
Antipsicóticos/uso terapêutico , Benzodiazepinas/uso terapêutico , Transtorno Bipolar/tratamento farmacológico , Discinesia Induzida por Medicamentos/etiologia , Transtornos Psicóticos/tratamento farmacológico , Esquizofrenia/tratamento farmacológico , Adulto , Antipsicóticos/efeitos adversos , Benzodiazepinas/efeitos adversos , Transtorno Bipolar/diagnóstico , Estudos Transversais , Discinesia Induzida por Medicamentos/diagnóstico , Discinesia Induzida por Medicamentos/epidemiologia , Feminino , Seguimentos , Hospitalização , Humanos , Masculino , Pessoa de Meia-Idade , Exame Neurológico/efeitos dos fármacos , Olanzapina , Transtornos Psicóticos/diagnóstico
12.
PLoS Pathog ; 4(3): e1000035, 2008 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-18369481

RESUMO

Persistent infection with the hepatitis C virus (HCV) is a major risk factor for the development of liver cirrhosis and hepatocellular carcinoma. With an estimated about 3% of the world population infected with this virus, the lack of a prophylactic vaccine and a selective therapy, chronic hepatitis C currently is a main indication for liver transplantation. The establishment of cell-based replication and virus production systems has led to first insights into the functions of HCV proteins. However, the role of nonstructural protein 5A (NS5A) in the viral replication cycle is so far not known. NS5A is a membrane-associated RNA-binding protein assumed to be involved in HCV RNA replication. Its numerous interactions with the host cell suggest that NS5A is also an important determinant for pathogenesis and persistence. In this study we show that NS5A is a key factor for the assembly of infectious HCV particles. We specifically identify the C-terminal domain III as the primary determinant in NS5A for particle formation. We show that both core and NS5A colocalize on the surface of lipid droplets, a proposed site for HCV particle assembly. Deletions in domain III of NS5A disrupting this colocalization abrogate infectious particle formation and lead to an enhanced accumulation of core protein on the surface of lipid droplets. Finally, we show that mutations in NS5A causing an assembly defect can be rescued by trans-complementation. These data provide novel insights into the production of infectious HCV and identify NS5A as a major determinant for HCV assembly. Since domain III of NS5A is one of the most variable regions in the HCV genome, the results suggest that viral isolates may differ in their level of virion production and thus in their level of fitness and pathogenesis.


Assuntos
Hepacivirus/fisiologia , Proteínas não Estruturais Virais/metabolismo , Proteínas Virais/metabolismo , Montagem de Vírus/fisiologia , Carcinoma Hepatocelular , Linhagem Celular Tumoral , Técnica Indireta de Fluorescência para Anticorpo , Hepacivirus/química , Hepacivirus/ultraestrutura , Antígenos da Hepatite C/análise , Antígenos da Hepatite C/metabolismo , Humanos , Mutação , Estrutura Terciária de Proteína , RNA Viral/metabolismo , Proteínas do Core Viral/análise , Proteínas do Core Viral/metabolismo , Proteínas não Estruturais Virais/química
13.
J Virol ; 81(9): 4591-603, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17301154

RESUMO

Studies of the complete hepatitis C virus (HCV) life cycle have become possible with the development of an infectious cell culture system using the genotype 2a isolate JFH-1. Taking advantage of this system in the present study, we investigated whether HCV infection leads to superinfection exclusion, a state in which HCV-infected cells are resistant to secondary HCV infection. To discriminate between viral genomes, we inserted genes encoding fluorescent proteins in frame into the 3'-terminal NS5A coding region. These genomes replicated to wild-type levels and supported the production of infectious virus particles. Upon simultaneous infection of Huh-7 cells, co-replication of both viral genomes in the same cell was detected. However, when infections were performed sequentially, secondary infection was severely impaired. This superinfection exclusion was neither due to a reduction of cell surface expression of CD81 and scavenger receptor BI, two molecules implicated in HCV entry, nor due to a functional block at the level of virus entry. Instead, superinfection exclusion was mediated primarily by interference at the level of HCV RNA translation and, presumably, also replication. In summary, our results describe the construction and characterization of viable monocistronic HCV reporter genomes allowing detection of viral replication in infected living cells. By using these genomes, we found that HCV induces superinfection exclusion, which is primarily due to interference at a post-entry step.


Assuntos
Regulação Viral da Expressão Gênica/fisiologia , Genoma Viral/genética , Hepacivirus/fisiologia , Interferência Viral , Northern Blotting , Linhagem Celular , Primers do DNA , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Imunofluorescência , Técnicas de Transferência de Genes , Humanos , Luciferases , Replicação Viral
16.
J Virol ; 79(5): 3187-94, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15709040

RESUMO

Nonstructural protein 5A of the hepatitis C virus (HCV) is a highly phosphorylated molecule implicated in multiple interactions with the host cell and most likely involved in RNA replication. Two phosphorylated variants of NS5A have been described, designated according to their apparent molecular masses (in kilodaltons) as p56 and p58, which correspond to the basal and hyperphosphorylated forms, respectively. With the aim of identifying a possible role of NS5A phosphorylation for RNA replication, we performed an extensive mutation analysis of three serine clusters that are involved in phosphorylation and hyperphosphorylation of NS5A. In most cases, alanine substitutions for serine residues in the central cluster 1 that enhanced RNA replication to the highest levels led to a reduction of NS5A hyperphosphorylation. Likewise, several highly adaptive mutations in NS4B, which is also part of the replication complex, resulted in a reduction of NS5A hyperphosphorylation too, arguing that alterations of the NS5A phosphorylation pattern play an important role for RNA replication. On the other hand, a deletion encompassing all highly conserved serine residues in the C-terminal region of NS5A that are involved in basal phosphorylation did not significantly affect RNA replication but reduced formation of p56. This region was found to tolerate even large insertions with only a moderate effect on replication. Based on these results, we propose a model of the role of NS5A phosphorylation in the viral life cycle.


Assuntos
Hepacivirus/genética , Hepacivirus/metabolismo , RNA Viral/biossíntese , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo , Substituição de Aminoácidos , Linhagem Celular , Humanos , Mutação , Fosforilação , Estrutura Terciária de Proteína , RNA Viral/genética , RNA Polimerase Dependente de RNA/química , RNA Polimerase Dependente de RNA/genética , RNA Polimerase Dependente de RNA/metabolismo , Serina/química , Proteínas não Estruturais Virais/química
17.
J Virol ; 79(2): 896-909, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15613318

RESUMO

Studies of Hepatitis C virus (HCV) RNA replication have become possible with the development of subgenomic replicons. This system allows the functional analysis of the essential components of the viral replication complex, which so far are poorly defined. In the present study we wanted to investigate whether lethal mutations in HCV nonstructural genes can be rescued by trans-complementation. Therefore, a series of replicon RNAs carrying mutations in NS3, NS4B, NS5A, and NS5B that abolish replication were transfected into Huh-7 hepatoma cells harboring autonomously replicating helper RNAs. Similar to data described for the Bovine viral diarrhea virus (C. W. Grassmann, O. Isken, N. Tautz, and S. E. Behrens, J. Virol. 75:7791-7802, 2001), we found that only NS5A mutants could be efficiently rescued. There was no evidence for RNA recombination between helper and mutant RNAs, and we did not observe reversions in the transfected mutants. Furthermore, we established a transient complementation assay based on the cotransfection of helper and mutant RNAs. Using this assay, we extended our results and demonstrated that (i) inactivating NS5A mutations affecting the amino-terminal amphipathic helix cannot be complemented in trans; (ii) replication of the helper RNA is not necessary to allow efficient trans-complementation; and (iii) the minimal sequence required for trans-complementation of lethal NS5A mutations is NS3 to -5A, whereas NS5A expressed alone does not restore RNA replication. In summary, our results provide the first insight into the functional organization of the HCV replication complex.


Assuntos
Hepacivirus/genética , RNA Viral/biossíntese , Proteínas não Estruturais Virais/fisiologia , Linhagem Celular Tumoral , Teste de Complementação Genética , Humanos , Estrutura Secundária de Proteína , Replicon , Proteínas não Estruturais Virais/química , Proteínas não Estruturais Virais/genética
18.
J Biol Chem ; 279(39): 40835-43, 2004 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-15247283

RESUMO

Hepatitis C virus (HCV) nonstructural protein 5A (NS5A) is a membrane-associated, essential component of the viral replication complex. Here, we report the three-dimensional structure of the membrane anchor domain of NS5A as determined by NMR spectroscopy. An alpha-helix extending from amino acid residue 5 to 25 was observed in the presence of different membrane mimetic media. This helix exhibited a hydrophobic, Trprich side embedded in detergent micelles, while the polar, charged side was exposed to the solvent. Thus, the NS5A membrane anchor domain forms an in-plane amphipathic alpha-helix embedded in the cytosolic leaflet of the membrane bilayer. Interestingly, mutations affecting the positioning of fully conserved residues located at the cytosolic surface of the helix impaired HCV RNA replication without interfering with the membrane association of NS5A. In conclusion, the NS5A membrane anchor domain constitutes a unique platform that is likely involved in specific interactions essential for the assembly of the HCV replication complex and that may represent a novel target for antiviral intervention.


Assuntos
Membrana Celular/metabolismo , Proteínas não Estruturais Virais/química , Sequência de Aminoácidos , Anticorpos Monoclonais/química , Linhagem Celular Tumoral , Citosol/metabolismo , Humanos , Bicamadas Lipídicas/química , Espectroscopia de Ressonância Magnética , Micelas , Microscopia Confocal , Modelos Moleculares , Dados de Sequência Molecular , Mutação , Peptídeos/química , Plasmídeos/metabolismo , Conformação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Transcrição Gênica , Transfecção , Proteínas não Estruturais Virais/metabolismo
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