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In recent years, the function of noncoding RNAs (ncRNAs) as regulatory molecules of cell physiology has begun to be better understood. Advances in viral molecular biology have shown that host ncRNAs, cellular factors, and virus-derived ncRNAs and their interplay are strongly disturbed during viral infections. Nevertheless, the folding of RNA virus genomes has also been identified as a critical factor in regulating canonical and non-canonical functions. Due to the influence of host ncRNAs and the structure of RNA viral genomes, complex molecular and cellular processes in infections are modulated. We propose three main categories to organize the current information about RNA-RNA interactions in some well-known human viruses. The first category shows examples of host ncRNAs associated with the immune response triggered in viral infections. Even though miRNAs introduce a standpoint, they are briefly presented to keep researchers moving forward in uncovering other RNAs. The second category outlines interactions between virus-host ncRNAs, while the third describes how the structure of the RNA viral genome serves as a scaffold for processing virus-derived RNAs. Our grouping may provide a comprehensive framework to classify ncRNA-host-cell interactions for emerging viruses and diseases. In this sense, we introduced them to organize DENV-host-cell interactions.
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Virus del Dengue , Genoma Viral , ARN no Traducido , ARN Viral , Virus del Dengue/genética , Virus del Dengue/fisiología , Humanos , ARN no Traducido/genética , ARN no Traducido/metabolismo , ARN Viral/genética , ARN Viral/metabolismo , Interacciones Huésped-Patógeno/genética , Dengue/virología , MicroARNs/genética , MicroARNs/metabolismo , AnimalesRESUMEN
In recent years, a population of small RNA fragments derived from non-coding RNAs (sfd-RNAs) has gained significant interest due to its functional and structural resemblance to miRNAs, adding another level of complexity to our comprehension of small-RNA-mediated gene regulation. Despite this, scientists need more tools to test the differential expression of sfd-RNAs since the current methods to detect miRNAs may not be directly applied to them. The primary reasons are the lack of accurate small RNA and ncRNA annotation, the multi-mapping read (MMR) placement, and the multicopy nature of ncRNAs in the human genome. To solve these issues, a methodology that allows the detection of differentially expressed sfd-RNAs, including canonical miRNAs, by using an integrated copy-number-corrected ncRNA annotation was implemented. This approach was coupled with sixteen different computational strategies composed of combinations of four aligners and four normalization methods to provide a rank-order of prediction for each differentially expressed sfd-RNA. By systematically addressing the three main problems, we could detect differentially expressed miRNAs and sfd-RNAs in dengue virus-infected human dermal microvascular endothelial cells. Although more biological evaluations are required, two molecular targets of the hsa-mir-103a and hsa-mir-494 (CDK5 and PI3/AKT) appear relevant for dengue virus (DENV) infections. Here, we performed a comprehensive annotation and differential expression analysis, which can be applied in other studies addressing the role of small fragment RNA populations derived from ncRNAs in virus infection.
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Dengue virus (DENV) is a pathogenic arbovirus that causes human disease. The most severe stage of the disease (severe dengue) is characterized by vascular leakage, hypovolemic shock, and organ failure. Endothelial dysfunction underlies these phenomena, but the causal mechanisms of endothelial dysfunction are poorly characterized. This study investigated the role of c-ABL kinase in DENV-induced endothelial dysfunction. Silencing c-ABL with artificial miRNA or targeting its catalytic activity with imatinib revealed that c-ABL is required for the early steps of DENV infection. DENV-2 infection and conditioned media from DENV-infected cells increased endothelial expression of c-ABL and CRKII phosphorylation, promoted expression of mesenchymal markers, e.g., vimentin and N-cadherin, and decreased the levels of endothelial-specific proteins, e.g., VE-cadherin and ZO-1. These effects were reverted by silencing or inhibiting c-ABL. As part of the acquisition of a mesenchymal phenotype, DENV infection and treatment with conditioned media from DENV-infected cells increased endothelial cell motility in a c-ABL-dependent manner. In conclusion, DENV infection promotes a c-ABL-dependent endothelial phenotypic change that leads to the loss of intercellular junctions and acquisition of motility.
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Virus del Dengue , Dengue , Virosis , Humanos , Células Endoteliales , Virus del Dengue/genética , Medios de Cultivo Condicionados/farmacología , Medios de Cultivo Condicionados/metabolismo , Virosis/metabolismoRESUMEN
Dengue virus (DENV) infection is the most arbovirosis in the world. However, medications have not been approved for its treatment. Drug discovery based on the host-targeted antiviral (HTA) constitutes a new promising strategy, considering their high genetic barrier to resistance and the low probability of selecting drug resistance strains. In this study, we have tested fifty-seven podophyllotoxin-related cyclolignans on DENV-2 infected cells and found the most promising compound was S.71. Using cellular and molecular biology experiments, we have discovered that the new lignan altered the distribution of microtubules, induced changes in cell morphology, and caused retraction of the rough endoplasmic reticulum. In addition, the compound alters the viral envelope protein and the double-stranded RNA, while there is a decrease in negative-strand RNA synthesis; especially when the compound was added between 6- and 12-hours post-infection. Altogether, S.71 decreases the viral yield through an HTA-related mechanism of action, possibly altering the DENV genome replication and/or polyprotein translation, through the alteration of microtubule distribution and endoplasmic reticulum deterioration. Finally, pharmacokinetic predictors show that S.71 falls within the standard ranges established for drugs.
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Virus del Dengue , Dengue , Virosis , Humanos , Virus del Dengue/genética , Antivirales/uso terapéutico , Replicación Viral , Técnicas de Cultivo de Célula , Virosis/tratamiento farmacológico , Dengue/tratamiento farmacológicoRESUMEN
Zika virus (ZIKV), a flavivirus that is mainly transmitted by A. aegypti and A. albopictus and sexual transmission, has been documented and described. The ZIKV RNA detection in the semen of vasectomized men indicates that accessory glands such as the prostate could be a site of virus replication. In this study, we characterized the ZIKV infection, evaluated the antiviral profile, and demonstrated the AXL and TIM-1 expression on the PC3 prostate cell line. It was also determined that PC3 cells are susceptible and permissive to ZIKV infection without altering the cell viability or causing a cytopathic effect. The antiviral profile suggests that the PC3 cells modulate the antiviral response through the suppressor molecule expression, SOCS-1, during a ZIKV infection.
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Similar to other RNA viruses, the emergence of Betacoronavirus relies on cross-species viral transmission, which requires careful health surveillance monitoring of protein-coding information as well as genome-wide analysis. Although the evolutionary jump from natural reservoirs to humans may be mainly traced-back by studying the effect that hotspot mutations have on viral proteins, it is largely unexplored if other impacts might emerge on the structured RNA genome of Betacoronavirus. In this survey, the protein-coding and viral genome architecture were simultaneously studied to uncover novel insights into cross-species horizontal transmission events. We analysed 1,252,952 viral genomes of SARS-CoV, MERS-CoV, and SARS-CoV-2 distributed across the world in bats, intermediate animals, and humans to build a new landscape of changes in the RNA viral genome. Phylogenetic analyses suggest that bat viruses are the most closely related to the time of most recent common ancestor of Betacoronavirus, and missense mutations in viral proteins, mainly in the S protein S1 subunit: SARS-CoV (G > T; A577S); MERS-CoV (C > T; S746R and C > T; N762A); and SARS-CoV-2 (A > G; D614G) appear to have driven viral diversification. We also found that codon sites under positive selection on S protein overlap with non-compensatory mutations that disrupt secondary RNA structures in the RNA genome complement. These findings provide pivotal factors that might be underlying the eventual jumping the species barrier from bats to intermediate hosts. Lastly, we discovered that nearly half of the Betacoronavirus genomes carry highly conserved RNA structures, and more than 90% of these RNA structures show negative selection signals, suggesting essential functions in the biology of Betacoronavirus that have not been investigated to date. Further research is needed on negatively selected RNA structures to scan for emerging functions like the potential of coding virus-derived small RNAs and to develop new candidate antiviral therapeutic strategies.
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COVID-19 , Quirópteros , Animales , COVID-19/genética , Quirópteros/genética , Humanos , Mutación , Filogenia , ARN , SARS-CoV-2/genética , Glicoproteína de la Espiga del Coronavirus/genética , Proteínas ViralesRESUMEN
Virus-related mortality and morbidity are due to cell/tissue damage caused by replicative pressure and resource exhaustion, e.g., HBV or HIV; exaggerated immune responses, e.g., SARS-CoV-2; and cancer, e.g., EBV or HPV. In this context, oncogenic and other types of viruses drive genetic and epigenetic changes that expand the tumorigenic program, including modifications to the ability of cancer cells to migrate. The best-characterized group of changes is collectively known as the epithelial-mesenchymal transition, or EMT. This is a complex phenomenon classically described using biochemistry, cell biology and genetics. However, these methods require enormous, often slow, efforts to identify and validate novel therapeutic targets. Systems biology can complement and accelerate discoveries in this field. One example of such an approach is Boolean networks, which make complex biological problems tractable by modeling data ("nodes") connected by logical operators. Here, we focus on virus-induced cellular plasticity and cell reprogramming in mammals, and how Boolean networks could provide novel insights into the ability of some viruses to trigger uncontrolled cell proliferation and EMT, two key hallmarks of cancer.
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Plasticidad de la Célula/genética , Redes Reguladoras de Genes , Virosis/patología , Virus/patogenicidad , Animales , Reprogramación Celular/genética , Transición Epitelial-Mesenquimal/genética , Humanos , Neoplasias/genética , Neoplasias/patología , Biología de Sistemas , Virosis/genética , Virus/clasificaciónRESUMEN
RESUMEN La Transición Epitelio-Mesénquima (EMT) es un proceso de diferenciación altamente conservado en vertebrados. Este ocurre en células epiteliales con la activación progresiva de la pérdida de la polaridad, la adquisición de motilidad individual y la capacidad invasiva a otros tejidos. La EMT es un proceso normal durante el desarrollo; no obstante, en condiciones patológicas está relacionada con la inducción de metástasis, lo cual representa una vía alterna al desarrollo de procesos oncogénicos tempranos. Aunque la EMT es activada principalmente por factores de crecimiento, también se puede desencadenar por infecciones de patógenos intracelulares mediante la activación de rutas moleculares inductoras de este proceso. Por lo tanto, una infección bacteriana o viral pueda generar predisposición al desarrollo de tumores. Nuestro interés está enfocado principalmente en caracterizar la relación virus-hospedero, y en el caso de los virus, varios ya se han descrito como inductores de la EMT. En este artículo de revisión se describen el fenómeno de la plasticidad celular y la ocurrencia detallada del proceso de EMT, los patógenos virales reportados como inductores, los mecanismos moleculares usados para ello y las vías de regulación mediante miRNAs. Por último, se discute cómo esta relación virus-hospedero puede explicar la patogénesis de la enfermedad causada por Dengue virus, favoreciendo la identificación de blancos moleculares para terapia, estrategia conocida como Antivirales dirigidos a blancos celulares o HTA (Host-targeting antivirals).
ABSTRACT Epithelial-to-Mesenchymal Transition (EMT) is a highly conserved dedifferentiation process in vertebrates. This process occurs in epithelial cells activating progressive loss of cell polarity, acquisition of individual motility and invasive capacity to other tissues. EMT is a normal process during development process, however, in pathological conditions is related to the induction of metastasis, which represents an alternative path to the development of early oncogenic processes. Although, EMT is mainly activated by growth factors, it can also be triggered by intracellular-pathogen-infections by activating molecular pathways that induce this process. Therefore, a bacterial or viral infection may generate predisposition to the development of tumors. Our interest is mainly focused on characterizing the host-virus relationship, and in the case of viruses, several have already been described as EMT inductors. In this review, phenomenon of cellular plasticity, detailed occurrence of the EMT, viral pathogens reported as inducers, the molecular mechanisms, and the regulatory pathways through miRNAs are described. Finally, we discuss how this host-virus relationship may explain the pathogenesis of the disease caused by Dengue virus, favoring the identification of molecular targets for therapy, a strategy known as Host-Targeting Antivirals (HTA).
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RESUMEN El diseño eficiente de compuestos aprovechando las características estructurales de las moléculas y la búsqueda eficiente de dianas terapéuticas, ha proporcionado herramientas efectivas en la investigación de nuevos tratamientos cuando esta se enfoca en mecanismos celulares de la enfermedad. Los cambios fenotípicos producidos por la interacción in vitro entre molécula-diana, pueden controlarse cuantitativamente mediante imagenología de células vivas. Para garantizar una interacción adecuada, es necesario considerar diferentes elementos cruciales: 1. Las características estructurales y la dinámica molecular del compuesto a evaluar. 2. La relevancia del blanco para la fisiopatología de interés. Sin embargo, el desconocimiento del panorama general en el descubrimiento de fármacos, desde problemáticas estructurales y celulares, ha enlentecido la búsqueda de nuevos tratamientos. Esta revisión descriptiva de tema presenta algunos aspectos estructurales importantes para la caracterización de compuestos como candidatos terapéuticos, y aproximaciones experimentales para desarrollo de sistemas celulares. Los tópicos discutidos se enfocan en la monitorización por imagenología de células vivas y así mismo proporcionamos ejemplos relevantes. La monitorización de efectos fenotípicos producidos por interacciones entre candidato químico y blanco terapéutico en un sistema celular puede favorecer la búsqueda eficiente de moléculas potencialmente terapéuticas.
SUMMARY The efficient compounds' design taking advantage of the molecule's structural characteristics and efficient search for therapeutic targets has provided effective tools for the research of new treatments when this is focused on disease cellular mechanisms. Phenotypic changes produced by in vitro interaction between molecules and targets can be monitored quantitatively by live cell imaging. To guarantee adequate interaction, it is necessary to consider different crucial elements: 1. Structural characteristics and molecular dynamics of the evaluated compound. 2. Target relevance for the concern physiopathology. However, overview's ignorance of the drug discovery, from structural and cellular problems, has slowed the new treatments research. This literature review presents some important structural aspects for compounds' characterization as therapeutic candidates and experimental approaches for cellular systems development. Subjects discussed are focused on live cell imaging and we also provide relevant examples. Phenotypic monitoring of interactions' produced effects between the chemical candidate and therapeutic target in a cellular system can favor the efficient search of potentially therapeutic molecules.
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BACKGROUND: Viruses can modulate intracellular signalling pathways to complete their infectious cycle. Among these, the PI3K/Akt pathway allows prolonged survival of infected cells that favours viral replication. GSK3ß, a protein kinase downstream of PI3K/Akt, gets inactivated upon activation of the PI3K/Akt pathway, and its association with viral infections has been recently established. In this study, the role of GSK3ß during Dengue virus-2 (DENV-2) infection was investigated. METHODS: GSK3ß participation in the DENV-2 replication process was evaluated with pharmacological and genetic inhibition during early [0-12 h post-infection (hpi)], late (12-24 hpi), and 24 hpi in Huh7 and Vero cells. We assessed the viral and cellular processes by calculating the viral titre in the supernatants, In-Cell Western, western blotting and fluorescence microscopy. RESULTS: Phosphorylation of GSK3ß-Ser9 was observed at the early stages of infection; neither did treatment with small molecule inhibitors nor pre-treatment prior to viral infection of GSK3ß reduce viral titres of the supernatant at these time points. However, a decrease in viral titres was observed in cells infected and treated with the inhibitors much later during viral infection. Consistently, the infected cells at this stage displayed plasma membrane damage. Nonetheless, these effects were not elicited with the use of genetic inhibitors of GSK3ß. CONCLUSIONS: The results suggest that GSK3ß participates at the late stages of the DENV replication cycle, where viral activation may promote apoptosis and release of viral particles.
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Virus del Dengue/enzimología , Glucógeno Sintasa Quinasas/antagonistas & inhibidores , Glucógeno Sintasa Quinasas/fisiología , Replicación Viral/fisiología , Aedes/citología , Animales , Apoptosis/fisiología , Western Blotting , Línea Celular Tumoral , Microscopía Fluorescente , Fosforilación/fisiología , Transducción de SeñalRESUMEN
BACKGROUND Viruses can modulate intracellular signalling pathways to complete their infectious cycle. Among these, the PI3K/Akt pathway allows prolonged survival of infected cells that favours viral replication. GSK3β, a protein kinase downstream of PI3K/Akt, gets inactivated upon activation of the PI3K/Akt pathway, and its association with viral infections has been recently established. In this study, the role of GSK3β during Dengue virus-2 (DENV-2) infection was investigated. METHODS GSK3β participation in the DENV-2 replication process was evaluated with pharmacological and genetic inhibition during early [0-12 h post-infection (hpi)], late (12-24 hpi), and 24 hpi in Huh7 and Vero cells. We assessed the viral and cellular processes by calculating the viral titre in the supernatants, In-Cell Western, western blotting and fluorescence microscopy. RESULTS Phosphorylation of GSK3β-Ser9 was observed at the early stages of infection; neither did treatment with small molecule inhibitors nor pre-treatment prior to viral infection of GSK3β reduce viral titres of the supernatant at these time points. However, a decrease in viral titres was observed in cells infected and treated with the inhibitors much later during viral infection. Consistently, the infected cells at this stage displayed plasma membrane damage. Nonetheless, these effects were not elicited with the use of genetic inhibitors of GSK3β. CONCLUSIONS The results suggest that GSK3β participates at the late stages of the DENV replication cycle, where viral activation may promote apoptosis and release of viral particles.
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Animales , Replicación Viral/fisiología , Virus del Dengue/enzimología , Glucógeno Sintasa Quinasas/antagonistas & inhibidores , Glucógeno Sintasa Quinasas/fisiología , Fosforilación/fisiología , Transducción de Señal , Western Blotting , Apoptosis/fisiología , Aedes/citología , Línea Celular Tumoral , Microscopía FluorescenteRESUMEN
RESUMEN La quinasa dependiente de ciclina 5 (CDK5) regula diversas funciones en neuronas, células endoteliales y epiteliales, entre ellas la dinámica del citoesqueleto. Así mismo, se ha reportado que componentes del citoesqueleto, tales como, filamentos de actina y microtúbulos juegan un rol importante durante la infección por el virus dengue (DENV). El objetivo del presente trabajo fue evaluar por dos métodos, inhibición química y silenciamiento génico, la participación de CDK5 durante la infección por DENV-2. La actividad antiviral de roscovitina fue evaluada usando ensayos de Unidades Formadoras de Placa (PFU). La eficiencia de transfección y el silenciamiento de CDK5, empleando miARNs artificiales, se determinó por citometría de flujo. El efecto sobre la proteína de envoltura viral y elementos del citoesqueleto se evidenció mediante microscopia avanzada de fluorescencia y análisis de imágenes. Roscovitina mostró actividad antiviral en etapas pre y post-infectivas en una forma dependiente de la dosis. El tratamiento con roscovitina y miRCDK5 mostró ser efectivo reduciendo la cantidad de CDK5 en células no infectadas. En células infectadas y transfectadas con miRCDK5, así como tratadas con el inhibidor, se observó una reducción significativa de la proteína de envoltura viral; sin embargo, no se encontró reducción significativa de CDK5. Además, el tratamiento con roscovitina indujo cambios celulares morfológicos evidentes en células infectadas. Los resultados indican la potencial participación de CDK5 durante la infección por DENV-2, posiblemente mediando la traducción proteica o la replicación del genoma viral a través de la regulación de la dinámica del citoesqueleto. Se requieren datos adicionales para esclarecer la mecanística del fenómeno usando métodos alternativos.
ABSTRACT Cyclin-Dependent Kinase 5 (CDK5) regulates several functions in neurons, endothelial, and epithelial cells, including the cytoskeleton dynamics. Likewise, it has been reported that some cytoskeleton elements, such as actin filaments and microtubules, play an essential role during Dengue virus (DENV) infection. This work aimed to evaluate the role of CDK5 during DENV-2 infection by two methods, chemical inhibition, and gene silencing. The antiviral activity of roscovitine was evaluated using Plaque Forming Units (PFU) assay. The transfection efficiency and knockdown of CDK5, using artificial miRNAs, was carried out by flow cytometry. The effect on the viral envelope protein and cytoskeleton elements was evidenced by advanced fluorescence microscopy and image analysis. Roscovitine showed antiviral activity in pre and post-infection stages in a dose-dependent manner. Treatment with roscovitine and miRCDK5 decrease the amount of CDK5 in uninfected cells. In cells infected and transfected with miRCDK5, as well as treated with the inhibitor, a significant reduction of the viral envelope protein was observed; however, no significant reduction of CDK5 was found. Also, evident morphological cellular changes were observed during the treatment with roscovitine in infected cells. The results indicate the potential participation of CDK5 during DENV-2 infection, possibly mediating protein translation or replication of the viral genome through the cytoskeletal dynamics regulation. Additional data are required to clarify the mechanistic of these phenomena using alternative methods.
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INTRODUCTION: In this study, we aimed to identify DENV-2 subtypes in Aedes aegypti pools collected between 2011 and 2017 in a rural area of Northern Cordoba, Colombia ("La Balsa"). METHODS: RT-PCR was performed to analyze the capsid/pre-membrane region (C-PrM). Sequencing and phylogenetic bayesian inference using reference DENV-2 sequences were performed. RESULTS: Twelve pools that tested positive for DENV-2 were characterized based on the C-PrM region and grouped under the Asian/American clade. CONCLUSIONS: This study is the first to report the DENV-2 Asian-American subtype in a rural area of Cordoba region, which is associated with severe dengue and local epidemics.
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Aedes/virología , Virus del Dengue/clasificación , Virus del Dengue/genética , Dengue/virología , Mosquitos Vectores/virología , Filogenia , Animales , Teorema de Bayes , Colombia/epidemiología , Dengue/epidemiología , Virus del Dengue/aislamiento & purificación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Serogrupo , Serotipificación , Dengue GraveRESUMEN
The most life-threatening effect of the Dengue virus (DENV) infection is an acute destabilization of the microvascular endothelial cell (MEC) barrier leading to plasma leakage, hypovolemic shock and haemorrhage. However, the underlying cellular mechanisms responsible for the dysfunction of MECs are not well understood. To identify potential cellular processes altered during DENV infection of MECs, expression profiles of cytokines/growth factors and microRNAs were measured by Luminex assay and next generation sequencing, respectively. Synchronously DENV2-infected MECs increase the secretion of IL-6, IL-8, FGF-2, GM-CSF, G-CSF, TGF-α, GRO, RANTES, MCP-1 and MCP-3. Conditioned media of infected MECs increased the migration of non-infected MECs. Furthermore, six miRNAs deregulated at 24 hpi were predicted to regulate host genes involved in cell migration and vascular developmental processes such as angiogenesis. These in silico analyses provide insights that support that DENV promotes an acute migratory phenotype in MECs that contributes to the vascular destabilization observed in severe dengue cases.
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Biomarcadores , Virus del Dengue/fisiología , Dengue/genética , Dengue/virología , Células Endoteliales/metabolismo , Células Endoteliales/virología , MicroARNs/genética , Animales , Línea Celular , Movimiento Celular/genética , Biología Computacional/métodos , Medios de Cultivo Condicionados/metabolismo , Citocinas/metabolismo , Dengue/sangre , Regulación de la Expresión Génica , Redes Reguladoras de Genes , Humanos , L-Lactato Deshidrogenasa/metabolismo , Transducción de SeñalRESUMEN
Abstract INTRODUCTION: In this study, we aimed to identify DENV-2 subtypes in Aedes aegypti pools collected between 2011 and 2017 in a rural area of Northern Cordoba, Colombia ("La Balsa"). METHODS: RT-PCR was performed to analyze the capsid/pre-membrane region (C-PrM). Sequencing and phylogenetic bayesian inference using reference DENV-2 sequences were performed. RESULTS: Twelve pools that tested positive for DENV-2 were characterized based on the C-PrM region and grouped under the Asian/American clade. CONCLUSIONS: This study is the first to report the DENV-2 Asian-American subtype in a rural area of Cordoba region, which is associated with severe dengue and local epidemics.
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Animales , Filogenia , Aedes/virología , Dengue/virología , Virus del Dengue/clasificación , Virus del Dengue/genética , Mosquitos Vectores/virología , Serotipificación , Teorema de Bayes , Colombia/epidemiología , Dengue Grave , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Dengue/epidemiología , Virus del Dengue/aislamiento & purificación , SerogrupoRESUMEN
BACKGROUND: Infection generated by Dengue Virus (DENV) does not have a specific pharmacologic treatment. Therefore, it is necessary to investigate research strategies departing from traditional approaches. Studying cellular mechanisms during early DENV infection may allow the design of a host-based approach to antivirals. Herein, we describe early/late events of DENV infection in mammalian cells related to PI3K/Akt, Rho GTPases, and the actin cytoskeleton. METHODS: To evaluate whether PI3K/Akt/Rho GTPases and the actin cytoskeleton participate in DENV replication in Huh7 cells, chemical and genetic inhibition were performed over 24 h.p.i., including early (1-12 h.p.i.) and late (12-24 h.p.i.) infection. Effects were evidenced by quantification of viral titers, activation of kinases assayed by western blot and In-Cell Western and subcellular patterns registered by quantitative fluorescence microscopy. RESULTS: DENV infections induced activation of PI3K/Akt with concomitant reorganization of the actin cytoskeleton, which was confirmed using specific chemical inhibitors. Additionally, inhibition of PI3K/Akt/Rho GTPases and actin microfilaments significantly reduced new viral progeny. Blocking the downstream effectors (ROCK and Rac1) of this pathway mimicked the cellular phenotype of PI3K/Akt/Rho GTPases inhibition. Furthermore, blockage of the final executor (i.e., actin) of this cellular process in infected cells also elicited molecular and viral effects. Finally, combined PI3K/Akt inhibition and Rho GTPases knockdown (Rac1, Rac2 and Cdc42), showed a similar effect on DENV-2 titer to that observed by individual treatment. CONCLUSIONS: Taken together, these findings suggest that the PI3K/Akt pathway is involved in DENV-2 infection in a Rho GTPase- and actin-dependent manner and that DENV-2 uses this signaling cascade to efficiently replicate in cells.
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Citoesqueleto de Actina/metabolismo , Virus del Dengue/crecimiento & desarrollo , Interacciones Huésped-Patógeno , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas de Unión al GTP rho/metabolismo , Animales , Western Blotting , Línea Celular , Chlorocebus aethiops , Inhibidores Enzimáticos/metabolismo , Células Epiteliales/virología , Técnicas de Silenciamiento del Gen , Hepatocitos/virología , Humanos , Microscopía Fluorescente , Transducción de Señal , Carga ViralRESUMEN
Dengue virus (DENV) is a member of the Flaviviridae family, which is transmitted to mammalian species through arthropods, and causes dengue fever or severe dengue fever in humans. The DENV genome encodes for multiple nonstructural (NS) proteins including NS1. NS1 plays an essential role in replication by interacting with other viral proteins including NS4B, however how these interactions are regulated during virus infection is not known. By using bioinformatics, mass spectrometry analysis, and co-immunoprecipitation assays, here we show that DENV-NS1 is ubiquitinated on multiples lysine residues during DENV infection, including K189, a lysine residue previously shown to be important for efficient DENV replication. Data from in vitro and cell culture experiments indicate that dengue NS1 undergoes modification with K48-linked polyubiquitin chains, which usually target proteins to the proteasome for degradation. Furthermore, ubiquitinated NS1 was detected in lysates as well as in supernatants of human and mosquito infected cells. Ubiquitin deconjugation of NS1 using the deubiquitinase OTU resulted in increased interaction with the viral protein NS4B suggesting that ubiquitinated NS1 has reduced affinity for NS4B. In support of these data, a K189R mutation on NS1, which abrogates ubiquitination on amino acid residue 189 of NS1, also increased NS1-NS4B interactions. Our work describes a new mechanism of regulation of NS1-NS4B interactions and suggests that ubiquitination of NS1 may affect DENV replication.
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Virus del Dengue/genética , Regulación Viral de la Expresión Génica , Lisina/metabolismo , Proteínas no Estructurales Virales/genética , Replicación Viral , Secuencia de Aminoácidos , Animales , Línea Celular Tumoral , Biología Computacional , Culicidae , Virus del Dengue/metabolismo , Células HEK293 , Hepatocitos/efectos de los fármacos , Hepatocitos/virología , Humanos , Mutación , Complejo de la Endopetidasa Proteasomal/metabolismo , Unión Proteica , Proteolisis , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Proteasas Ubiquitina-Específicas/química , Proteasas Ubiquitina-Específicas/farmacología , Ubiquitinación , Proteínas no Estructurales Virales/metabolismoRESUMEN
Arboviruses belonging to the genera Flavivirus and Alphavirus were detected in mosquitoes in a rural area of San Bernardo del Viento (Córdoba, Colombia). A total of 22,180 mosquitoes were collected, sorted into 2,102 pools, and tested by generic/nested reverse transcription-polymerase chain reaction. Venezuelan equine encephalitis virus, dengue virus, West Nile virus, St. Louis encephalitis virus, yellow fever virus, and Culex flavivirus were detected and identified by sequencing. The detection of arboviral pathogens in this zone represents possible circulation and indicates a human health risk, demonstrating the importance of virological surveillance activities.
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Alphavirus/genética , Culicidae/virología , Flavivirus/genética , Alphavirus/clasificación , Alphavirus/aislamiento & purificación , Animales , Región del Caribe , Colombia , Femenino , Flavivirus/clasificación , Humanos , Filogenia , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Población RuralRESUMEN
Arboviruses belonging to the genera Flavivirus and Alphavirus were detected in mosquitoes in a rural area of San Bernardo del Viento (Córdoba, Colombia). A total of 22,180 mosquitoes were collected, sorted into 2,102 pools, and tested by generic/nested reverse transcription-polymerase chain reaction. Venezuelan equine encephalitis virus, dengue virus, West Nile virus, St. Louis encephalitis virus, yellow fever virus, and Culex flavivirus were detected and identified by sequencing. The detection of arboviral pathogens in this zone represents possible circulation and indicates a human health risk, demonstrating the importance of virological surveillance activities.