Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Med Chem ; 64(15): 10951-10966, 2021 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-34260245

RESUMO

Influenza viruses cause approximately half a million deaths every year worldwide. Vaccines are available but partially effective, and the number of antiviral medications is limited. Thus, it is crucial to develop therapeutic strategies to counteract this major pathogen. Influenza viruses enter the host cell via their hemagglutinin (HA) proteins. The HA subtypes of influenza A virus are phylogenetically classified into groups 1 and 2. Here, we identified an inhibitor of the HA protein, a tertiary aryl sulfonamide, that prevents influenza virus entry and replication. This compound shows potent antiviral activity against diverse H1N1, H5N1, and H3N2 influenza viruses encoding HA proteins from both groups 1 and 2. Synthesis of derivatives of this aryl sulfonamide identified moieties important for antiviral activity. This compound may be considered as a lead for drug development with the intent to be used alone or in combination with other influenza A virus antivirals to enhance pan-subtype efficacy.


Assuntos
Antivirais/farmacologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Vírus da Influenza A/efeitos dos fármacos , Sulfonamidas/farmacologia , Antivirais/síntese química , Antivirais/química , Relação Dose-Resposta a Droga , Estrutura Molecular , Relação Estrutura-Atividade , Sulfonamidas/síntese química , Sulfonamidas/química , Internalização do Vírus/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos
2.
Sci Adv ; 7(6)2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33547084

RESUMO

The ongoing unprecedented severe acute respiratory syndrome caused by the SARS-CoV-2 outbreak worldwide has highlighted the need for understanding viral-host interactions involved in mechanisms of virulence. Here, we show that the virulence factor Nsp1 protein of SARS-CoV-2 interacts with the host messenger RNA (mRNA) export receptor heterodimer NXF1-NXT1, which is responsible for nuclear export of cellular mRNAs. Nsp1 prevents proper binding of NXF1 to mRNA export adaptors and NXF1 docking at the nuclear pore complex. As a result, a significant number of cellular mRNAs are retained in the nucleus during infection. Increased levels of NXF1 rescues the Nsp1-mediated mRNA export block and inhibits SARS-CoV-2 infection. Thus, antagonizing the Nsp1 inhibitory function on mRNA export may represent a strategy to restoring proper antiviral host gene expression in infected cells.


Assuntos
COVID-19/metabolismo , Expressão Gênica , Interações entre Hospedeiro e Microrganismos/genética , RNA Mensageiro/metabolismo , SARS-CoV-2/metabolismo , Proteínas não Estruturais Virais/metabolismo , Fatores de Virulência/metabolismo , Transporte Ativo do Núcleo Celular/genética , Animais , COVID-19/virologia , Chlorocebus aethiops , Células HEK293 , Humanos , Poro Nuclear/metabolismo , Proteínas de Transporte Nucleocitoplasmático/genética , Proteínas de Transporte Nucleocitoplasmático/metabolismo , RNA Mensageiro/genética , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , SARS-CoV-2/química , Transfecção , Células Vero , Proteínas não Estruturais Virais/genética
3.
PLoS Pathog ; 16(4): e1008407, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32240278

RESUMO

Influenza A viruses are human pathogens with limited therapeutic options. Therefore, it is crucial to devise strategies for the identification of new classes of antiviral medications. The influenza A virus genome is constituted of 8 RNA segments. Two of these viral RNAs are transcribed into mRNAs that are alternatively spliced. The M1 mRNA encodes the M1 protein but is also alternatively spliced to yield the M2 mRNA during infection. M1 to M2 mRNA splicing occurs at nuclear speckles, and M1 and M2 mRNAs are exported to the cytoplasm for translation. M1 and M2 proteins are critical for viral trafficking, assembly, and budding. Here we show that gene knockout of the cellular protein NS1-BP, a constituent of the M mRNA speckle-export pathway and a binding partner of the virulence factor NS1 protein, inhibits M mRNA nuclear export without altering bulk cellular mRNA export, providing an avenue to preferentially target influenza virus. We performed a high-content, image-based chemical screen using single-molecule RNA-FISH to label viral M mRNAs followed by multistep quantitative approaches to assess cellular mRNA and cell toxicity. We identified inhibitors of viral mRNA biogenesis and nuclear export that exhibited no significant activity towards bulk cellular mRNA at non-cytotoxic concentrations. Among the hits is a small molecule that preferentially inhibits nuclear export of a subset of viral and cellular mRNAs without altering bulk cellular mRNA export. These findings underscore specific nuclear export requirements for viral mRNAs and phenocopy down-regulation of the mRNA export factor UAP56. This RNA export inhibitor impaired replication of diverse influenza A virus strains at non-toxic concentrations. Thus, this screening strategy yielded compounds that alone or in combination may serve as leads to new ways of treating influenza virus infection and are novel tools for studying viral RNA trafficking in the nucleus.


Assuntos
Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Antivirais/farmacologia , Núcleo Celular/virologia , Vírus da Influenza A/metabolismo , Influenza Humana/virologia , RNA Mensageiro/metabolismo , RNA Viral/metabolismo , Avaliação Pré-Clínica de Medicamentos , Humanos , Vírus da Influenza A/genética , RNA Mensageiro/genética , RNA Viral/genética , Replicação Viral/efeitos dos fármacos
4.
Nat Microbiol ; 4(10): 1671-1679, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31263181

RESUMO

Influenza viruses antagonize key immune defence mechanisms via the virulence factor non-structural protein 1 (NS1). A key mechanism of virulence by NS1 is blocking nuclear export of host messenger RNAs, including those encoding immune factors1-3; however, the direct cellular target of NS1 and the mechanism of host mRNA export inhibition are not known. Here, we identify the target of NS1 as the mRNA export receptor complex, nuclear RNA export factor 1-nuclear transport factor 2-related export protein 1 (NXF1-NXT1), which is the principal receptor mediating docking and translocation of mRNAs through the nuclear pore complex via interactions with nucleoporins4,5. We determined the crystal structure of NS1 in complex with NXF1-NXT1 at 3.8 Å resolution. The structure reveals that NS1 prevents binding of NXF1-NXT1 to nucleoporins, thereby inhibiting mRNA export through the nuclear pore complex into the cytoplasm for translation. We demonstrate that a mutant influenza virus deficient in binding NXF1-NXT1 does not block host mRNA export and is attenuated. This attenuation is marked by the release of mRNAs encoding immune factors from the nucleus. In sum, our study uncovers the molecular basis of a major nuclear function of influenza NS1 protein that causes potent blockage of host gene expression and contributes to inhibition of host immunity.


Assuntos
Núcleo Celular/metabolismo , Vírus da Influenza A/fisiologia , Influenza Humana/metabolismo , RNA Mensageiro/metabolismo , Proteínas não Estruturais Virais/metabolismo , Células A549 , Transporte Ativo do Núcleo Celular , Sítios de Ligação , Células Cultivadas , Cristalografia por Raios X , Humanos , Vírus da Influenza A/genética , Vírus da Influenza A/metabolismo , Modelos Moleculares , Complexos Multiproteicos/química , Complexos Multiproteicos/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/química , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Proteínas de Transporte Nucleocitoplasmático/química , Proteínas de Transporte Nucleocitoplasmático/genética , Proteínas de Transporte Nucleocitoplasmático/metabolismo , Ligação Proteica , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas não Estruturais Virais/genética
6.
Nat Microbiol ; 1(7): 16069, 2016 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-27572970

RESUMO

Influenza A virus is a human pathogen with a genome composed of eight viral RNA segments that replicate in the nucleus. Two viral mRNAs are alternatively spliced. The unspliced M1 mRNA is translated into the matrix M1 protein, while the ion channel M2 protein is generated after alternative splicing. These proteins are critical mediators of viral trafficking and budding. We show that the influenza virus uses nuclear speckles to promote post-transcriptional splicing of its M1 mRNA. We assign previously unknown roles for the viral NS1 protein and cellular factors to an intranuclear trafficking pathway that targets the viral M1 mRNA to nuclear speckles, mediates splicing at these nuclear bodies and exports the spliced M2 mRNA from the nucleus. Given that nuclear speckles are storage sites for splicing factors, which leave these sites to splice cellular pre-mRNAs at transcribing genes, we reveal a functional subversion of nuclear speckles to promote viral gene expression.


Assuntos
Núcleo Celular/virologia , Vírus da Influenza A/genética , Corpos de Inclusão Intranuclear/metabolismo , Splicing de RNA , RNA Viral/metabolismo , Proteínas da Matriz Viral/genética , Processamento Alternativo , Linhagem Celular , Regulação Viral da Expressão Gênica , Genoma Viral , Interações Hospedeiro-Patógeno , Humanos , Vírus da Influenza A/patogenicidade , Vírus da Influenza A/fisiologia , Corpos de Inclusão Intranuclear/virologia , RNA Viral/genética , Proteínas da Matriz Viral/metabolismo , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo , Liberação de Vírus/genética , Liberação de Vírus/fisiologia
7.
Cancer Res ; 75(18): 3925-35, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26292362

RESUMO

Cell identity signals influence the invasive capability of tumor cells, as demonstrated by the selection for programs of epithelial-to-mesenchymal transition (EMT) during malignant progression. Breast cancer cells retain canonical epithelial traits and invade collectively as cohesive groups of cells, but the signaling pathways critical to their invasive capabilities are still incompletely understood. Here we report that the transcription factor ΔNp63α drives the migration of basal-like breast cancer (BLBC) cells by inducing a hybrid mesenchymal/epithelial state. Through a combination of expression analysis and functional testing across multiple BLBC cell populations, we determined that ΔNp63α induces migration by elevating the expression of the EMT program components Slug and Axl. Interestingly, ΔNp63α also increased the expression of miR-205, which can silence ZEB1/2 to prevent the loss of epithelial character caused by EMT induction. In clinical specimens, co-expression of various elements of the ΔNp63α pathway confirmed its implication in motility signaling in BLBC. We observed that activation of the ΔNp63α pathway occurred during the transition from noninvasive ductal carcinoma in situ to invasive breast cancer. Notably, in an orthotopic tumor model, Slug expression was sufficient to induce collective invasion of E-cadherin-expressing BLBC cells. Together, our results illustrate how ΔNp63α can drive breast cancer cell invasion by selectively engaging promigratory components of the EMT program while, in parallel, still promoting the retention of epithelial character.


Assuntos
Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Carcinoma Intraductal não Infiltrante/patologia , Transformação Celular Neoplásica/patologia , Transição Epitelial-Mesenquimal/fisiologia , Regulação Neoplásica da Expressão Gênica , Invasividade Neoplásica/fisiopatologia , Proteínas de Neoplasias/fisiologia , Fatores de Transcrição/fisiologia , Proteínas Supressoras de Tumor/fisiologia , Animais , Neoplasias da Mama/mortalidade , Caderinas/biossíntese , Caderinas/genética , Movimento Celular , Progressão da Doença , Células Epiteliais/patologia , Feminino , Xenoenxertos , Humanos , Estimativa de Kaplan-Meier , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , MicroRNAs/biossíntese , MicroRNAs/genética , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas/genética , RNA Interferente Pequeno/farmacologia , Receptores Proteína Tirosina Quinases/biossíntese , Receptores Proteína Tirosina Quinases/genética , Transdução de Sinais/fisiologia , Fatores de Transcrição da Família Snail , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , Transfecção , Células Tumorais Cultivadas
8.
J Clin Invest ; 125(5): 1927-43, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25844900

RESUMO

Tumor cells can engage in a process called collective invasion, in which cohesive groups of cells invade through interstitial tissue. Here, we identified an epigenetically distinct subpopulation of breast tumor cells that have an enhanced capacity to collectively invade. Analysis of spheroid invasion in an organotypic culture system revealed that these "trailblazer" cells are capable of initiating collective invasion and promote non-trailblazer cell invasion, indicating a commensal relationship among subpopulations within heterogenous tumors. Canonical mesenchymal markers were not sufficient to distinguish trailblazer cells from non-trailblazer cells, suggesting that defining the molecular underpinnings of the trailblazer phenotype could reveal collective invasion-specific mechanisms. Functional analysis determined that DOCK10, ITGA11, DAB2, PDFGRA, VASN, PPAP2B, and LPAR1 are highly expressed in trailblazer cells and required to initiate collective invasion, with DOCK10 essential for metastasis. In patients with triple-negative breast cancer, expression of these 7 genes correlated with poor outcome. Together, our results indicate that spontaneous conversion of the epigenetic state in a subpopulation of cells can promote a transition from in situ to invasive growth through induction of a cooperative form of collective invasion and suggest that therapeutic inhibition of trailblazer cell invasion may help prevent metastasis.


Assuntos
Neoplasias da Mama/patologia , Epigênese Genética , Regulação Neoplásica da Expressão Gênica , Genes Neoplásicos , Invasividade Neoplásica/genética , Metástase Neoplásica/genética , Proteínas de Neoplasias/fisiologia , Animais , Neoplasias da Mama/mortalidade , Linhagem Celular Tumoral , Movimento Celular , Extensões da Superfície Celular/fisiologia , Extensões da Superfície Celular/ultraestrutura , Epigênese Genética/genética , Transição Epitelial-Mesenquimal , Matriz Extracelular , Feminino , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Invasividade Neoplásica/patologia , Proteínas de Neoplasias/genética , Interferência de RNA , Organismos Livres de Patógenos Específicos , Esferoides Celulares , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/mortalidade , Neoplasias de Mama Triplo Negativas/patologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...