Search

Retinoic acid–inducible gene I–like receptors (RLRs) are cytosolic RNA sensors critical for initiation of antiviral immunity. Activation of RLRs following RNA recognition leads to production of antiviral genes and IFNs for induction of broad antiviral immunity. Although the RLRs are ubiquitously expressed, much of our understanding of these molecules comes from their study in epithelial cells and fibroblasts. However, RLR activation is critical for induction of immune function and long-term protective immunity. Recent work has focused on the roles of RLRs in immune cells and their contribution to programming of effective immune responses. This new understanding of RLR function in immune cells and immune programming has led to the development of vaccines and therapeutics targeting the RLRs. This review covers recent advances in our understanding of the contribution of RLRs to immune cell function during infection and the emerging RLR-targeting strategies for induction of immunity against cancer and viral infection.

PDF file - 520K

Influenza virus activates cellular inflammasome pathways, which can be either beneficial or detrimental to infection outcomes. Here, we investigated the role of the inflammasome-activated pore-forming protein gasdermin D (GSDMD) during infection. Ablation of GSDMD in knockout (KO) mice significantly attenuated virus-induced weight loss, lung dysfunction, lung histopathology, and mortality compared with wild type (WT) mice, despite similar viral loads. Infected GSDMD KO mice exhibited decreased inflammatory gene signatures revealed by lung transcriptomics, which also implicated a diminished neutrophil response. Importantly, neutrophil depletion in infected WT mice recapitulated the reduced mortality and lung inflammation observed in GSDMD KO animals, while having no additional protective effects in GSDMD KOs. These findings reveal a new function for GSDMD in promoting lung neutrophil responses that amplify influenza virus-induced inflammation and pathogenesis. Targeting the GSDMD/neutrophil axis may provide a new therapeutic avenue for treating severe influenza.

Interferons (IFN) are induced by sensing of self- and non-self DNA or genomic lesions by pathogen recognition receptors (PRR) that activate STING. These pathways must be kept in check by negative regulators to prevent unscheduled activation of IFN, which contributes to autoinflammation. Here we show that MEF2A as a novel negative regulator of inflammation that suppresses homeostatic induction of IFNs. Indeed, MEF2A deficiency results in the spontaneous production of type I IFN and robust downstream IFN-stimulated gene expression that coincided with a robust cellular antiviral state. Mechanistically, MEF2A depletion promoted the accumulation of R-loops that activate the DDX41/STING pathway. This pro-inflammatory pathway was dependent on ATR kinase activity, hallmark of the replicative stress response, was necessary for the activation of STING upon loss of MEF2A expression. Thus, our study connects MEF2A with protection from maladaptive type I IFN responses triggered by R-loop accumulation and links the DDX41-dependent activation of STING to the DNA damage response.

Seasonal influenza results in 3 to 5 million cases of severe disease and 250,000 to 500,000 deaths annually. Macrophages have been implicated in both the resolution and progression of the disease, but the drivers of these outcomes are poorly understood. We probed mouse lung transcriptomic datasets using the Digital Cell Quantifier algorithm to predict immune cell subsets that correlated with mild or severe influenza A virus (IAV) infection outcomes. We identified a novel lung macrophage population that transcriptionally resembled small serosal cavity macrophages and correlated with mild disease. Until now, the study of serosal macrophage translocation in the context of infections has been neglected. Here, we show that pleural macrophages (PMs) migrate from the pleural cavity to the lung after infection with pH1N1 A/California/04/2009 IAV. We found that the depletion of PMs increased morbidity and pulmonary inflammation. There were increased proinflammatory cytokines in the pleural cavity and an influx of neutrophils within the lung. Our results show PMs are recruited to the lung during IAV infection and contribute to recovery from influenza. This study expands our knowledge of PM plasticity and provides a new source of lung macrophages independent of monocyte recruitment and local proliferation.GRAPHICAL ABSTRACT

La comprensión de factores que influyen sobre la regulación del apetito y la saciedad conduce al planteamiento de intervenciones en la prevención y manejo de enfermedades relacionadas con el exceso del consumo de alimentos. El objetivo de este artículo es realizar una revisión de los procesos fisiológicos y factores ambientales que intervienen como mecanismos de regulación de la ingesta alimentaria. Dicha regulación y el mantenimiento de la homeostasis del balance energético del organismo están mediados por múltiples factores. Se destacan los mecanismos fisiológicos, regulados por el hipotálamo mediante la señalización periférica y central, en la que intervienen señales de apetito o de saciedad. Además, con el creciente aumento del peso corporal, se destaca el cambio en el paradigma de las teorías homeostáticas que predominaban para explicar la regulación de la ingesta alimentaria, ya que se han quedado limitadas para definir el fenómeno del comportamiento alimentario. En este punto, los factores relacionados con el medio ambiente y con el comportamiento del individuo se vuelven relevantes para ilustrar el proceso. Por tanto, el estudio del tema debe ser abordado no solo desde la fisiología, sino también desde disciplinas de las ciencias sociales y comportamentales, porque es claro que la alimentación cumple tanto un rol fisiológico como un rol sociocultural. Asimismo, aspectos de la modernidad como el comportamiento sedentario, el procesamiento industrial de alimentos y la amplia oferta de los mismos juegan un rol decisivo en la regulación del apetito y la saciedad.

Severe acute respiratory syndrome coronavirus 2 (SARS–CoV-2) is a worldwide health concern, and new treatment strategies are needed. Targeting inflammatory innate immunity pathways holds therapeutic promise, but effective molecular targets remain elusive. Here, we show that human caspase-4 (CASP4) and its mouse homolog, caspase-11 (CASP11), are up-regulated in SARS–CoV-2 infections and that CASP4 expression correlates with severity of SARS–CoV-2 infection in humans. SARS–CoV-2–infected Casp11−/− mice were protected from severe weight loss and lung pathology, including blood vessel damage, compared to wild-type (WT) mice and mice lacking the caspase downstream effector gasdermin-D (Gsdmd−/−). Notably, viral titers were similar regardless of CASP11 knockout. Global transcriptomics of SARS–CoV-2–infected WT, Casp11−/−, and Gsdmd−/− lungs identified restrained expression of inflammatory molecules and altered neutrophil gene signatures in Casp11−/− mice. We confirmed that protein levels of inflammatory mediators interleukin (IL)-1β, IL-6, and CXCL1, as well as neutrophil functions, were reduced in Casp11−/− lungs. Additionally, Casp11−/− lungs accumulated less von Willebrand factor, a marker for endothelial damage, but expressed more Kruppel-Like Factor 2, a transcription factor that maintains vascular integrity. Overall, our results demonstrate that CASP4/11 promotes detrimental SARS–CoV-2–induced inflammation and coagulopathy, largely independently of GSDMD, identifying CASP4/11 as a promising drug target for treatment and prevention of severe COVID-19.

Interferon-induced transmembrane protein 3 (IFITM3) is a host antiviral protein that alters cell membranes to block fusion of viruses. Published reports have identified conflicting pro- and antiviral effects of IFITM3 on SARS-CoV-2 in cultured cells, and its impact on viral pathogenesis in vivo remains unclear. Here, we show that IFITM3 knockout (KO) mice infected with mouse-adapted SARS-CoV-2 experienced extreme weight loss and lethality, while wild type (WT) mice lost minimal weight and recovered. KO mice had higher lung viral titers and increases in lung inflammatory cytokine levels, CD45-positive immune cell infiltration, and histopathology, compared to WT mice. Mechanistically, we observed disseminated viral antigen staining throughout the lung tissue and pulmonary vasculature in KO mice, while staining was observed in confined regions in WT lungs. Global transcriptomic analysis of infected lungs identified upregulation of gene signatures associated with interferons, inflammation, and angiogenesis in KO versus WT animals, highlighting changes in lung gene expression programs that precede severe lung pathology and fatality. Corroborating the protective effect of IFITM3 in vivo, K18-hACE2/IFITM3 KO mice infected with non-adapted SARS-CoV-2 showed enhanced, rapid weight loss and early death compared to control mice. Increased heart infection was observed in both mouse models in the absence of IFITM3, indicating that IFITM3 constrains extrapulmonary dissemination of SARS-CoV-2. Our results establish IFITM3 KO mice as a new animal model for studying severe SARS-CoV-2 infection of the lung and cardiovascular system, and overall demonstrate that IFITM3 is protective in SARS-CoV-2 infections of mice.

SARS-CoV-2 is a worldwide health concern, and new treatment strategies are needed 1. Targeting inflammatory innate immunity pathways holds therapeutic promise, but effective molecular targets remain elusive. Here, we show that human caspase-4 (CASP4), and its mouse homologue, caspase-11 (CASP11), are upregulated in SARS-CoV-2 infections, and that CASP4 expression correlates with severity of SARS-CoV-2 infection in humans. SARS-CoV-2-infected Casp11-/- mice were protected from severe weight loss and lung pathology, including blood vessel damage, compared to wild-type (WT) and gasdermin-D knock out (Gsdmd-/-) mice. GSDMD is a downstream effector of CASP11 and CASP1. Notably, viral titers were similar in the three genotypes. Global transcriptomics of SARS-CoV-2-infected WT, Casp11-/- and Gsdmd-/- lungs identified restrained expression of inflammatory molecules and altered neutrophil gene signatures in Casp11-/- mice. We confirmed that protein levels of inflammatory mediators IL-1β, IL6, and CXCL1, and neutrophil functions, were reduced in Casp11-/- lungs. Additionally, Casp11-/- lungs accumulated less von Willebrand factor, a marker for endothelial damage, but expressed more Kruppel-Like Factor 2, a transcription factor that maintains vascular integrity. Overall, our results demonstrate that CASP4/11, promotes detrimental SARS-CoV-2-associated inflammation and coagulopathy, largely independently of GSDMD, identifying CASP4/11 as a promising drug target for treatment and prevention of severe COVID-19.

Coronavirus disease (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is characterized by a delayed interferon (IFN) response and high levels of proinflammatory cytokine expression. Type I and III IFNs serve as a first line of defense during acute viral infections and are readily antagonized by viruses to establish productive infection. A rapidly growing body of work has interrogated the mechanisms by which SARS-CoV-2 antagonizes both IFN induction and IFN signaling to establish productive infection. Here, we summarize these findings and discuss the molecular interactions that prevent viral RNA recognition, inhibit the induction of IFN gene expression, and block the response to IFN treatment. We also describe the mechanisms by which SARS-CoV-2 viral proteins promote host shutoff. A detailed understanding of the host-pathogen interactions that unbalance the IFN response is critical for the design and deployment of host-targeted therapeutics to manage COVID-19.

Common approaches to alleviate acute graft-versus-host disease (aGvHD) focus on inducing immune tolerance by directly targeting immune cells. However, protecting key target tissues such as the gastrointestinal tract from immune-mediated damage may also reduce aGvHD severity. Using murine aGvHD models, Henden and colleagues present compelling evidence that interferon λ (IFN- λ) limits intestinal stem cell loss and promotes regeneration of gut epithelia, preserving mucosal barrier function. They propose IFN- λ therapy as a novel strategy to boost tissue protection., Key Points IFN-λ receptor signaling protects against lethal acute GI GVHD.Recombinant IL-29 treatment in the peri-transplant period promotes gut epithelial regeneration and is a promising therapy to limit GVHD., Visual Abstract, Immunopathology and intestinal stem cell (ISC) loss in the gastrointestinal (GI) tract is the prima facie manifestation of graft-versus-host disease (GVHD) and is responsible for significant mortality after allogeneic bone marrow transplantation (BMT). Approaches to prevent GVHD to date focus on immune suppression. Here, we identify interferon-λ (IFN-λ; interleukin-28 [IL-28]/IL-29) as a key protector of GI GVHD immunopathology, notably within the ISC compartment. Ifnlr1−/− mice displayed exaggerated GI GVHD and mortality independent of Paneth cells and alterations to the microbiome. Ifnlr1−/− intestinal organoid growth was significantly impaired, and targeted Ifnlr1 deficiency exhibited effects intrinsic to recipient Lgr5+ ISCs and natural killer cells. PEGylated recombinant IL-29 (PEG-rIL-29) treatment of naive mice enhanced Lgr5+ ISC numbers and organoid growth independent of both IL-22 and type I IFN and modulated proliferative and apoptosis gene sets in Lgr5+ ISCs. PEG-rIL-29 treatment improved survival, reduced GVHD severity, and enhanced epithelial proliferation and ISC-derived organoid growth after BMT. The preservation of ISC numbers in response to PEG-rIL-29 after BMT occurred both in the presence and absence of IFN-λ–signaling in recipient natural killer cells. IFN-λ is therefore an attractive and rapidly testable approach to prevent ISC loss and immunopathology during GVHD.

Many host RNA sensors are positioned in the cytosol to detect viral RNA during infection. However, most positive-strand RNA viruses replicate within a modified organelle co-opted from intracellular membranes of the endomembrane system, which shields viral products from cellular innate immune sensors. Targeting innate RNA sensors to the endomembrane system may enhance their ability to sense RNA generated by viruses that use these compartments for replication. Here, we reveal that an isoform of oligoadenylate synthetase 1, OAS1 p46, is prenylated and targeted to the endomembrane system. Membrane localization of OAS1 p46 confers enhanced access to viral replication sites and results in increased antiviral activity against a subset of RNA viruses including flaviviruses, picornaviruses, and SARS-CoV-2. Finally, our human genetic analysis shows that the OAS1 splice-site SNP responsible for production of the OAS1 p46 isoform correlates with protection from severe COVID-19. This study highlights the importance of endomembrane targeting for the antiviral specificity of OAS1 and suggests that early control of SARS-CoV-2 replication through OAS1 p46 is an important determinant of COVID-19 severity.

IFNs are comprised of three families of cytokines that confer protection against pathogen infection and uncontrolled cellular proliferation. The broad role IFNs play in innate and adaptive immune regulation has placed them under heavy scrutiny to position them as “friend” or “foe” across pathologies. Genetic lesions in genes involving IFN synthesis and signaling underscore the disparate outcomes of aberrant IFN signaling. Abrogation of the response leads to susceptibility to microbial infections whereas unabated IFN induction underlies a variety of inflammatory diseases and tumor immune evasion. Type I and III IFNs have overlapping roles in antiviral protection, yet the mechanisms by which they are induced and promote the expression of IFN-stimulated genes and inflammation can distinguish their biological functions. In this review, we examine the molecular factors that shape the shared and distinct roles of type I and III IFNs in immunity.

SUMMARYMany host RNA sensors are positioned in the cytosol to detect viral RNA during infection. However, most positive-strand RNA viruses replicate within a modified organelle co-opted from intracellular membranes of the endomembrane system, which shields viral products from host cell innate immune sensors. Targeting innate RNA sensors to the endomembrane system may enhance their ability to sense viral RNA generated by viruses that use these compartments for replication. Here, we reveal that an isoform of oligoadenylate synthetase 1, OAS1 p46, is prenylated and targeted to the endomembrane system. Membrane localization of OAS1 p46 confers enhanced access to viral replication sites and results in increased antiviral activity against a subset of RNA viruses including flavivirus, picornavirus, and SARS-CoV-2. Finally, our human genetic analysis shows that the OAS1 splice-site SNP responsible for production of the OAS1 p46 isoform strongly associates with COVID-19 severity. This study highlights the importance of endomembrane targeting for the antiviral specificity of OAS1 and suggests early control of SARS-CoV-2 replication through OAS1-p46 is an important determinant of COVID-19 severity.

Cardiopulmonary bypass (CPB) is required during most cardiac surgeries. CBP drives systemic inflammation and multi-organ dysfunction that is more severe in neonatal patients. Limited understanding of molecular mechanisms underlying CPB-associated inflammation presents a significant barrier to improving clinical outcomes. To better understand these clinical issues, we performed the first mRNA-sequencing on total circulating leukocytes from neonatal patients undergoing CPB. These data identified myeloid cells, particularly monocytes, as the major cell type driving transcriptional responses to CPB. Furthermore, Interleukin-8 (IL8) and Tumor Necrosis Factor-α (TNFα) were inflammatory cytokines robustly upregulated in leukocytes from both patients and piglets exposed to CPB. To delineate a molecular mechanism, we exposed THP-1 human monocytic cells to CPB-like conditions including artificial surfaces, high shear stress, and cooling/rewarming. Here, shear stress was found to drive cytokine upregulation via calcium-dependent signaling pathways. We also observed a subpopulation of THP-1 cells died via TNFα-mediated necroptosis in our model, which we hypothesize contributes to post-CPB inflammation. Together, our study identifies a shear-stress modulated molecular mechanism that drives systemic inflammation in pediatric CPB patients. These are also the first data to demonstrate that shear-stress causes necroptosis. Finally, we observe that calcium and TNFα signaling are novel targets to ameliorate post-CPB inflammation.

Interferons (IFN) are antiviral cytokines induced by recognition of viral nucleic acids or cellular replicative stress. In particular, the accumulation of cytosolic nucleic acids or the accumulation of DNA lesions has the potential to activate cGAS/STING-mediated IFN induction if not properly constrained. While these responses can be harnessed as tumor therapies, the excessive induction of IFNs and deleterious IFN-mediated inflammation is associated with tissue damage in non-malignant disease. We sought to identify non-canonical IFN-modulatory transcription factors (TF) by examining factors with known genetic alterations that associate with both malignant and inflammatory diseases. Here, we identify MEF2A as a negative regulator of the production of IFNs at homeostasis. The loss of MEF2A function results in the spontaneous induction of type I and III IFNs and downstream ISG expression. We demonstrate that IFN production following MEF2A depletion was dependent on DNA replication and cell cycle progression with CDK2 inhibition ablating this response. Furthermore, DNA lesions that induced DNA damage responses following MEF2A loss resulted in cGAS/STING pathway activation and genetic deletion of STING maintained homeostatic levels of type I IFN in the absence of this TF factor. Thus, our study is first to connect MEF2A with protection from maladaptive type I IFN responses due to genomic instability across various cell types. Overall, our study reveals that therapeutic modulation of MEF2A or other members of its family could be beneficial for the management of viral, malignant, and autoinflammatory diseases.

Pathogenic flaviviruses antagonize host cell Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling downstream of interferons &alpha, /&beta, Here, we show that flaviviruses inhibit JAK/STAT signaling induced by a wide range of cytokines beyond interferon, including interleukins. This broad inhibition was mapped to viral nonstructural protein 5 (NS5) binding to cellular heat shock protein 90 (HSP90), resulting in reduced Janus kinase&ndash, HSP90 interaction and thus destabilization of unchaperoned JAKs (and other kinase clients) of HSP90 during infection by Zika virus, West Nile virus, and Japanese encephalitis virus. Our studies implicate viral dysregulation of HSP90 and the JAK/STAT pathway as a critical determinant of cytokine signaling control during flavivirus infection.

Long noncoding RNAs (lncRNAs) exhibit highly lineage-specific expression and act through diverse mechanisms to exert control over a wide range of cellular processes. lncRNAs can function as potent modulators of innate immune responses through control of transcriptional and posttranscriptional regulation of mRNA expression and processing. Recent studies have demonstrated that lncRNAs participate in the regulation of antiviral responses and autoimmune disease. Despite their emerging role as immune mediators, the mechanisms that govern lncRNA expression and function have only begun to be characterized. In this study, we explore the role of lncRNAs in human plasmacytoid dendritic cells (pDCs), which are critical sentinel sensors of viral infection and contribute to the development of autoimmune disease. Using genome-wide sequencing approaches, we dissect the contributions of Toll-like receptor 7 (TLR7) and type I interferon (IFN-I) in the regulation of coding and noncoding RNA expression in CAL-1 pDCs treated with R848 or IFNβ. Functional enrichment analysis reveals both the unique and synergistic roles of TLR7 and IFN-I signaling in the orchestration of pDC function. These observations were consistent with primary cell immune responses elicited by detection of viral infection. We identified and characterized the conditional TLR7- and IFN-I-dependent regulation of 588 lncRNAs. Dysregulation of these lncRNAs could significantly alter pDC maturation, IFN-I and inflammatory cytokine production, antigen presentation, costimulation or tolerance cues, turnover, or localization, all consequential events during viral infection or IFN-I-driven autoimmune diseases such as systemic lupus erythematosus. These findings demonstrate the differential responsiveness of lncRNAs to unique immune stimuli, uncover regulatory mechanisms of lncRNA expression, and reveal a novel and tractable platform for the study of lncRNA expression and function.

MicroRNAs (miRNAs) play an important role in fine-tuning host immune homeostasis and responses through the regulation of messenger RNA (mRNA) stability and translation. Studies have demonstrated that miRNA-mediated regulation of gene expression has a profound impact on immune cell development, function and response to invading pathogens. As we continue to examine the mechanisms by which miRNAs maintain the balance between robust protective host immune responses and dysregulated responses that promote immune pathology, careful consideration of the complexity of post-transcriptional immune regulation is needed. Distinct tissue- and stimulus-specific RNA-RNA and RNA-protein interactions can modulate the functions of a given miRNA. Thus, new challenges emerge in the identification of post-transcriptional co-regulatory modules and the genetic factors that impact miRNA function.

The initial response to viral infection is anticipatory, with host antiviral restriction factors and pathogen sensors constantly surveying the cell to rapidly mount an antiviral response through the synthesis and downstream activity of interferons. After pathogen clearance, the host's ability to resolve this antiviral response and return to homeostasis is critical. Here, we found that isoforms of the RNA-binding protein ZAP functioned as both a direct antiviral restriction factor and an interferon-resolution factor. The short isoform of ZAP bound to and mediated the degradation of several host interferon messenger RNAs, and thus acted as a negative feedback regulator of the interferon response. In contrast, the long isoform of ZAP had antiviral functions and did not regulate interferon. The two isoforms contained identical RNA-targeting domains, but differences in their intracellular localization modulated specificity for host versus viral RNA, which resulted in disparate effects on viral replication during the innate immune response.

This work evaluate the protective characteristic of the CO2 corrosion product layers formed on the surface of two types of steels, API 5L X80 used for transportation of oil and gas, and API 5CT P110 used for case tubing and pipe for oil drilling.Electrochemistry evaluations and morphological characterization of the obtained layer were performed. These steels were exposed to a brine solution containing 3% wt of NaCl, in a pressurized autoclave with 55 bar of CO2 and total pressure of 75 bar at different temperatures (25, 50 and 75°C) and immersion times (7, 15, 21 and 30 days). The corrosion rate was determined by mass loss tests and electrochemical techniques, such as Linear Polarization Resistance and Electrochemical Impedance Spectroscopy. Characteristics of the corrosion product layer such as thickness, morphology, and chemical composition were analyzed by scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS) and X-Ray diffraction (XRD). The corrosion rate decreases with the increase of the immersion time and temperature, and the lower rate of corrosion was obtained for 75°C after 30 days of immersion, for both steels

Summary Type I and III interferons (IFNs) activate similar downstream signaling cascades, but unlike type I IFNs, type III IFNs (IFNλ) do not elicit strong inflammatory responses in vivo. Here, we examined the molecular mechanisms underlying this disparity. Type I and III IFNs displayed kinetic differences in expression of IFN-stimulated genes and proinflammatory responses, with type I IFNs preferentially stimulating expression of the transcription factor IRF1. Type III IFNs failed to induce IRF1 expression because of low IFNλ receptor abundance and insufficient STAT1 activation on epithelial cells and thus did not activate the IRF1 proinflammatory gene program. Rather, IFNλ stimulation preferentially induced factors implicated in tissue repair. Our findings suggest that IFN receptor compartmentalization and abundance confer a spatiotemporal division of labor where type III IFNs control viral spread at the site of the infection while restricting tissue damage; the transient induction of inflammatory responses by type I IFNs recruits immune effectors to promote protective immunity.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO FUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DO RIO DE JANEIRO PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO BOLSA NOTA 10 A susceptibilidade à corrosão sob tensão em aços para dutos é dependente de uma série de eventos que vão desde a manufatura do aço, fabricação do tubo, montagem dos dutos e tipo de substância transportada pelo duto. O procedimento de soldagem envolvido na montagem dos dutos pode modificar as propriedades mecânicas do metal de base na região da zona termicamente afetada (ZTA), assim como as propriedades metalúrgicas e de resistência à corrosão, tornando potencialmente a região da junta soldada com maior probabilidade de incidência de corrosão sob tensão.Este trabalho tem como objetivo estudar a resistência à corrosão sob tensão em presença de sulfeto e fragilização pelo hidrogênio, em soldas circunferenciais de tubo API 5L X80. Foram realizados: -Ensaios de acordo com norma NACE TM0177/96, Método A -Ensaios de Baixa Taxa de Deformação (BTD) de acordo com a norma ASTM G129-00/2006, em solução contendo Tiossulfato de Sódio. Os resultados mostraram que o metal base foi considerado aprovado segundo os requisitos dos testes NACE TM0177/96. Porém as juntas soldadas originadas nos diferentes processos de soldagem estudados apresentaram susceptibilidade à corrosão sob tensão em presença de sulfeto e fragilização pelo hidrogênio, segundo o mesmo critério, fraturando em um período inferior a 720h. Esta susceptibilidade foi comprovada com os resultados dos ensaios de tração BTD, tendo sido constatada uma queda significativa no limite de resistência, alongamento e tempo de ruptura, em comparação aos ensaios realizados ao ar na mesma taxa de deformação. O mecanismo de fratura predominante nos ensaios foi fratura transgranular. The susceptibility of pipeline steels to stress corrosion cracking (SCC) depends on a series of factors ranging from the manufacture of the steel, the pipe fabrication, the assembly of the pipeline and the type of substances to be transported. Additionally, the welding procedures adopted during the production of the tubes and for construction of the pipelines (field welding), can modify the properties of the base metal in the heat affected zone (HAZ), potentially rendering this region susceptible to sulphide stress corrosion cracking and hydrogen embrittlement.This study evaluates the resistance of girth welds in API 5LX80 pipes to hydrogen embrittlement and also to stress corrosion cracking in the presence of sulphides. The evaluation was performed according to NACE TM0177/96, Method A, applying the criterion of fracture/no fracture, and slow strain rate tensile tests (SSRT) were undertaken using a sodium thiosulphate solution according to the ASTM G29 standard. According to the requirements of the NACE TM0177/96 test, the base metal was considered approved. The weld metal exhibited susceptibility to SCC in the presence of sulphides, failling in a period of less than 720h. The susceptibility of the welded joint to SCC in the presence of sulphides was confirmed by the results obtained with SSRT tensile tests, where a significant decrease in the ultimate tensile strength, elongation and time to fracture were observed. The mechanism of fracture for the tests was predominantly transgranular.

Recent avian and swine-origin influenza virus outbreaks illustrate the ongoing threat of influenza pandemics. We investigated immunogenicity and protective efficacy of a multi-antigen (MA) universal influenza DNA vaccine consisting of HA, M2, and NP antigens in cynomolgus macaques. Following challenge with a heterologous pandemic H1N1 strain, vaccinated animals exhibited significantly lower viral loads and more rapid viral clearance when compared to unvaccinated controls. The MA DNA vaccine induced robust serum and mucosal antibody responses but these high antibody titers were not broadly neutralizing. In contrast, the vaccine induced broadly-reactive NP specific T cell responses that cross-reacted with the challenge virus and inversely correlated with lower viral loads and inflammation. These results demonstrate that a MA DNA vaccine that induces strong cross-reactive T cell responses can, independent of neutralizing antibody, mediate significant cross-protection in a nonhuman primate model and further supports development as an effective approach to induce broad protection against circulating and emerging influenza strains.

Ebola virus (EBOV) and Reston virus (RESTV) are members of the Ebolavirus genus which greatly differ in their pathogenicity. While EBOV causes a severe disease in humans characterized by a dysregulated inflammatory response and elevated cytokine and chemokine production, there are no reported disease-associated human cases of RESTV infection, suggesting that RESTV is nonpathogenic for humans. The underlying mechanisms determining the pathogenicity of different ebolavirus species are not yet known. In this study, we dissected the host response to EBOV and RESTV infection in primary human monocyte-derived macrophages (MDMs). As expected, EBOV infection led to a profound proinflammatory response, including strong induction of type I and type III interferons (IFNs). In contrast, RESTV-infected macrophages remained surprisingly silent. Early activation of IFN regulatory factor 3 (IRF3) and NF-κB was observed in EBOV-infected, but not in RESTV-infected, MDMs. In concordance with previous results, MDMs treated with inactivated EBOV and Ebola virus-like particles (VLPs) induced NF-κB activation mediated by Toll-like receptor 4 (TLR4) in a glycoprotein (GP)-dependent manner. This was not the case in cells exposed to live RESTV, inactivated RESTV, or VLPs containing RESTV GP, indicating that RESTV GP does not trigger TLR4 signaling. Our results suggest that the lack of immune activation in RESTV-infected MDMs contributes to lower pathogenicity by preventing the cytokine storm observed in EBOV infection. We further demonstrate that inhibition of TLR4 signaling abolishes EBOV GP-mediated NF-κB activation. This finding indicates that limiting the excessive TLR4-mediated proinflammatory response in EBOV infection should be considered as a potential supportive treatment option for EBOV disease. IMPORTANCE Emerging infectious diseases are a major public health concern, as exemplified by the recent devastating Ebola virus (EBOV) outbreak. Different ebolavirus species are associated with widely varying pathogenicity in humans, ranging from asymptomatic infections for Reston virus (RESTV) to severe disease with fatal outcomes for EBOV. In this comparative study of EBOV- and RESTV-infected human macrophages, we identified key differences in host cell responses. Consistent with previous data, EBOV infection is associated with a proinflammatory signature triggered by the surface glycoprotein (GP), which can be inhibited by blocking TLR4 signaling. In contrast, infection with RESTV failed to stimulate a strong host response in infected macrophages due to the inability of RESTV GP to stimulate TLR4. We propose that disparate proinflammatory host signatures contribute to the differences in pathogenicity reported for ebolavirus species and suggest that proinflammatory pathways represent an intriguing target for the development of novel therapeutics.

The objective of the present study is to investigate the relationships between body composition, nutritional profile, muscular fitness (MF) and bone health in a sample of children and adolescents from Colombia. Participants included 1118 children and adolescents (54.6% girls). Calcaneal broadband ultrasound attenuation (c-BUA) was obtained as a marker of bone health. Body composition (fat mass and lean mass) was assessed using bioelectrical impedance analysis. Furthermore height, weight, waist circumference and Tanner stage were measured and body mass index (BMI) was calculated. Standing long-jump (SLJ) and isometric handgrip dynamometry were used respectively as indicators of lower and upper body muscular fitness. A muscular index score was also computed by summing up the standardised values of both SLJ and handgrip strength. Dietary intake and degree of adherence to the Mediterranean diet were assessed by a 7-day recall questionnaire for food frequency and the Kidmed questionnaire. Poor bone health was considered using a z-score cut off of ≤−1.5 standard deviation. Once the results were adjusted for age and Tanner stage, the predisposing factors of having a c-BUA z-score ≤−1.5 standard deviation included being underweight or obese, having an unhealthy lean mass, having an unhealthy fat mass, SLJ performance, handgrip performance, and unhealthy muscular index score. In conclusion, body composition (fat mass and lean body mass) and MF both influenced bone health in a sample of children and adolescents from Colombia. Thus promoting strength adaptation and preservation in Colombian youth will help to improve bone health, an important protective factor against osteoporosis in later life.

Polyomaviruses encode a large T Ag (LT), a multifunctional protein essential for the regulation of both viral and host cell gene expression and productive viral infection. Previously, we have shown that stable expression of LT protein results in upregulation of genes involved in the IFN induction and signaling pathway. In this study, we focus on the cellular signaling mechanism that leads to the induction of IFN responses by LT. Our results show that ectopic expression of SV40 LT results in the induction of IFN-stimulated genes (ISGs) in human fibroblasts and confers an antiviral state. We describe a LT-initiated DNA damage response (DDR) that activates IFN regulatory factor 1, causing IFN-β production and consequent ISG expression in human cells. This IFN-β and ISG induction is dependent on ataxia-telangiectasia mutated and Rad3-related (ATR) kinase, but independent of ATM. ATR kinase inhibition using a selective kinase inhibitor (ETP-46464) caused a decrease in IFN regulatory factor 1 stabilization and ISG expression. Furthermore, expression of a mutant LT that does not induce DDR also does not induce IFN-β and ISGs. These results show that, in the absence of viral infection, LT-initiated activation of ATR-dependent DDR is sufficient for the induction of an IFN-β–mediated innate immune response in human cells. Thus, we have uncovered a novel and critical role for ATR as a mediator of antiviral responses utilizing LT.

Primary effusion lymphoma (PEL), associated with the latent infection by KSHV, constitutively expresses interferon-regulatory factor 4 (IRF4). We recently showed that IRF4 differentially regulates expression of cellular interferon-stimulated genes (ISGs) and viral genes (Forero et al., 2013). Here, using inducible IRF4 knockdown, we demonstrate that IRF4 silencing results in enhanced transcription of KSHV replication transactivator RTA. As a result viral transcription is increased leading to virus reactivation. Taken together, our results show that IRF4 helps maintain the balance between latency and KSHV reactivation in PEL cells.

Virus infection is sensed in the cytoplasm by retinoic acid-inducible gene I (RIG-I, also known as DDX58), which requires RNA and polyubiquitin binding to induce type I interferon (IFN) and activate cellular innate immunity. We show that the human IFN-inducible oligoadenylate synthetases-like (OASL) protein has antiviral activity and mediates RIG-I activation by mimicking polyubiquitin. Loss of OASL expression reduced RIG-I signaling and enhanced virus replication in human cells. Conversely, OASL expression suppressed replication of a number of viruses in a RIG-I-dependent manner and enhanced RIG-I-mediated IFN induction. OASL interacted and colocalized with RIG-I, and through its C-terminal ubiquitin-like domain specifically enhanced RIG-I signaling. Bone-marrow-derived macrophages from mice deficient for Oasl2 showed that among the two mouse orthologs of human OASL, Oasl2 is functionally similar to human OASL. Our findings show a mechanism by which human OASL contributes to host antiviral responses by enhancing RIG-I activation.

Author(s): Forero, Adriana; Tisoncik-Go, Jennifer; Watanabe, Tokiko; Zhong, Gongxun; Hatta, Masato; Tchitchek, Nicolas; Selinger, Christian; Chang, Jean; Barker, Kristi; Morrison, Juliet; Berndt, Jason D; Moon, Randall T; Josset, Laurence; Kawaoka, Yoshihiro; Katze, Michael G | Abstract: UnlabelledThe 1918-1919 influenza pandemic remains the single greatest infectious disease outbreak in the past century. Mouse and nonhuman primate infection models have shown that the 1918 virus induces overly aggressive innate and proinflammatory responses. To understand the response to viral infection and the role of individual 1918 genes on the host response to the 1918 virus, we examined reassortant avian viruses nearly identical to the pandemic 1918 virus (1918-like avian virus) carrying either the 1918 hemagglutinin (HA) or PB2 gene. In mice, both genes enhanced 1918-like avian virus replication, but only the mammalian host adaptation of the 1918-like avian virus through reassortment of the 1918 PB2 led to increased lethality. Through the combination of viral genetics and host transcriptional profiling, we provide a multidimensional view of the molecular mechanisms by which the 1918 PB2 gene drives viral pathogenicity. We demonstrate that 1918 PB2 enhances immune and inflammatory responses concomitant with increased cellular infiltration in the lung. We also show for the first time, that 1918 PB2 expression results in the repression of both canonical and noncanonical Wnt signaling pathways, which are crucial for inflammation-mediated lung regeneration and repair. Finally, we utilize regulatory enrichment and network analysis to define the molecular regulators of inflammation, epithelial regeneration, and lung immunopathology that are dysregulated during influenza virus infection. Taken together, our data suggest that while both HA and PB2 are important for viral replication, only 1918 PB2 exacerbates lung damage in mice infected with a reassortant 1918-like avian virus.ImportanceAs viral pathogenesis is determined in part by the host response, understanding the key host molecular driver(s) of virus-mediated disease, in relation to individual viral genes, is a promising approach to host-oriented drug efforts in preventing disease. Previous studies have demonstrated the importance of host adaptive genes, HA and PB2, in mediating disease although the mechanisms by which they do so are still poorly understood. Here, we combine viral genetics and host transcriptional profiling to show that although both 1918 HA and 1918 PB2 are important mediators of efficient viral replication, only 1918 PB2 impacts the pathogenicity of an avian influenza virus sharing high homology to the 1918 pandemic influenza virus. We demonstrate that 1918 PB2 enhances deleterious inflammatory responses and the inhibition of regeneration and repair functions coordinated by Wnt signaling in the lungs of infected mice, thereby promoting virus-associated disease.

One of the main ways to inhibit the corrosion is the adsorption of organic compounds on the surface of a metal. This study reports the behavior of six different organic inhibitors in a system carbon steel AISI-SAE1020/brine 3%w of NaCl/ gas mixture of 6% volume of CO2/10 ppm of H2S/ hydrocarbon. Two primary amines with sixteen and eighteen atoms of carbon were used, a secondary amine with twenty atoms and three carboxylic acids of sixteen, eighteen and twenty carbon atoms. Linear polarization resistance measurements were used, along with Tafel extrapolation and electrochemical impedances to assess the influence of temperature, velocity of fluid, inhibitor concentration and concentration of oleic phase on the inhibition efficiency in the Electrode of Rotational Cylinder, ECR. Activation and adsorption energies were calculated for the processes of corrosion in the system; according to the values derived, it was possible to define the system brine/CO2/H2S/ inhibitor, as a process with mixed control, where the phenomenon of mass transfer and that of charge transfer are in competition and the values obtained for the energy of adsorption of Gibbs, allowed checking that these compounds showed a chemical adsorption on the metallic surface. Under critical testing conditions (4 m/s, 59ºC or 332,15K) the amines present a better efficiency than carboxylic acids, thus complying with the electro-negativity theory applied to inhibitors. It was then possible to establish by the results obtained for the with hydrocarbon cuts tests, that this parameter adversely affects the percentage efficiency of the inhibitor.