RESUMEN
Coronavirus disease 2019 (COVID-19), the illness caused by a novel coronavirus now called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to more than 260 million confirmed infections and 5 million deaths to date. While vaccination is a powerful tool to control pandemic spread, medication to relieve COVID-19-associated symptoms and alleviate disease progression especially in high-risk patients is still lacking. In this study, we explore the suitability of the rapid accelerated fibrosarcoma/mitogen-activated protein kinase/extracellular signal-regulated kinase (Raf/MEK/ERK) pathway as a druggable target in the treatment of SARS-CoV-2 infections. We find that SARS-CoV-2 transiently activates Raf/MEK/ERK signaling in the very early infection phase and that ERK1/2 knockdown limits virus replication in cell culture models. We demonstrate that ATR-002, a specific inhibitor of the upstream MEK1/2 kinases which is currently evaluated in clinical trials as an anti-influenza drug, displays strong anti-SARS-CoV-2 activity in cell lines as well as in primary air-liquid-interphase epithelial cell (ALI) cultures, with a safe and selective treatment window. We also observe that ATR-002 treatment impairs the SARS-CoV-2-induced expression of pro-inflammatory cytokines, and thus might prevent COVID-19-associated hyperinflammation, a key player in COVID-19 progression. Thus, our data suggest that the Raf/MEK/ERK signaling cascade may represent a target for therapeutic intervention strategies against SARS-CoV-2 infections and that ATR-002 is a promising candidate for further drug evaluation.
Asunto(s)
Antivirales/farmacología , Tratamiento Farmacológico de COVID-19 , Fenamatos/farmacología , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , SARS-CoV-2/efectos de los fármacos , Células A549 , Adulto , Animales , COVID-19/metabolismo , Línea Celular , Células Cultivadas , Chlorocebus aethiops , Citocinas/metabolismo , Humanos , Inflamación/tratamiento farmacológico , Inflamación/metabolismo , MAP Quinasa Quinasa 1/antagonistas & inhibidores , MAP Quinasa Quinasa 1/metabolismo , MAP Quinasa Quinasa 2/antagonistas & inhibidores , MAP Quinasa Quinasa 2/metabolismo , SARS-CoV-2/fisiología , Células Vero , Replicación Viral/efectos de los fármacosRESUMEN
Influenza viruses (IV) exploit a variety of signaling pathways. Previous studies showed that the rapidly accelerated fibrosarcoma/mitogen-activated protein kinase/extracellular signal-regulated kinase (Raf/MEK/ERK) pathway is functionally linked to nuclear export of viral ribonucleoprotein (vRNP) complexes, suggesting that vRNP export is a signaling-induced event. However, the underlying mechanism remained completely enigmatic. Here we have dissected the unknown molecular steps of signaling-driven vRNP export. We identified kinases RSK1/2 as downstream targets of virus-activated ERK signaling. While RSK2 displays an antiviral role, we demonstrate a virus-supportive function of RSK1, migrating to the nucleus to phosphorylate nucleoprotein (NP), the major constituent of vRNPs. This drives association with viral matrix protein 1 (M1) at the chromatin, important for vRNP export. Inhibition or knockdown of MEK, ERK or RSK1 caused impaired vRNP export and reduced progeny virus titers. This work not only expedites the development of anti-influenza strategies, but in addition demonstrates converse actions of different RSK isoforms.
Asunto(s)
Virus de la Influenza A/metabolismo , Gripe Humana/virología , Ribonucleoproteínas/metabolismo , Transporte Activo de Núcleo Celular , Núcleo Celular/metabolismo , Núcleo Celular/virología , Humanos , Virus de la Influenza A/genética , Gripe Humana/genética , Gripe Humana/metabolismo , Sistema de Señalización de MAP Quinasas , Señales de Exportación Nuclear , Ribonucleoproteínas/genética , Proteínas Quinasas S6 Ribosómicas 90-kDa/genética , Proteínas Quinasas S6 Ribosómicas 90-kDa/metabolismo , Proteínas de la Matriz Viral/genética , Proteínas de la Matriz Viral/metabolismoRESUMEN
Small RNA viruses only have a very limited coding capacity, thus most viral proteins have evolved to fulfill multiple functions. The highly conserved matrix protein 1 (M1) of influenza A viruses is a prime example for such a multifunctional protein, as it acts as a master regulator of virus replication whose different functions have to be tightly regulated. The underlying mechanisms, however, are still incompletely understood. Increasing evidence points towards an involvement of posttranslational modifications in the spatio-temporal regulation of M1 functions. Here, we analyzed the role of M1 tyrosine phosphorylation in genuine infection by using recombinant viruses expressing M1 phosphomutants. Presence of M1 Y132A led to significantly decreased viral replication compared to wildtype and M1 Y10F. Characterization of phosphorylation dynamics by mass spectrometry revealed the presence of Y132 phosphorylation in M1 incorporated into virions that is most likely mediated by membrane-associated Janus kinases late upon infection. Molecular dynamics simulations unraveled a potential phosphorylation-induced exposure of the positively charged linker domain between helices 4 and 5, supposably acting as interaction platform during viral assembly. Consistently, M1 Y132A showed a defect in lipid raft localization due to reduced interaction with viral HA protein resulting in a diminished structural stability of viral progeny and the formation of filamentous particles. Importantly, reduced M1-RNA binding affinity resulted in an inefficient viral genome incorporation and the production of non-infectious virions that interferes with virus pathogenicity in mice. This study advances our understanding of the importance of dynamic phosphorylation as a so far underestimated level of regulation of multifunctional viral proteins and emphasizes the potential feasibility of targeting posttranslational modifications of M1 as a novel antiviral intervention.
Asunto(s)
Virus de la Influenza A/metabolismo , Mutación Missense , Proteínas de la Matriz Viral/metabolismo , Células A549 , Sustitución de Aminoácidos , Animales , Perros , Femenino , Células HEK293 , Humanos , Virus de la Influenza A/genética , Células de Riñón Canino Madin Darby , Masculino , Ratones , Ratones Transgénicos , Fosforilación , Proteínas de la Matriz Viral/genéticaRESUMEN
The innate immune system, in particular the type I interferon (IFN) response, is a powerful defence against virus infections. In turn, many if not all viruses have evolved various means to circumvent, resist, or counteract this host response to ensure efficient replication and propagation. Influenza viruses are no exception to this rule, and several viral proteins have been described to possess IFN-antagonistic functions. Although the viral nonstructural protein 1 appears to be a major antagonist in influenza A and B viruses (IAV and IBV), we have previously shown that a specific motif in the IAV polymerase proteins exerts an IFN-suppressive function very early in infection. The question remained whether a similar function would also exist in IBV polymerases. Here, we show that indeed a specific amino acid position (A523) of the PB1 protein in the IBV polymerase complex confers IFN-antagonistic properties. Mutation of this position leads to enhanced activation of the IFN-mediated signalling pathway after infection and subsequent reduction of virus titres. This indicates that inhibition of innate immune responses is a conserved activity shared by polymerase proteins of IAV and IBV.
Asunto(s)
Virus de la Influenza B , Interferón Tipo I/antagonistas & inhibidores , Proteínas de la Nucleocápside/inmunología , ARN Polimerasa Dependiente del ARN/inmunología , Proteínas Virales/inmunología , Células A549 , Animales , Chlorocebus aethiops , Células HEK293 , Interacciones Huésped-Patógeno , Humanos , Inmunidad Innata , Virus de la Influenza B/enzimología , Virus de la Influenza B/inmunología , Gripe Humana/virología , Células VeroRESUMEN
Influenza virus infections represent a major public health issue by causing annual epidemics and occasional pandemics that affect thousands of people worldwide. Vaccination is the main prophylaxis to prevent these epidemics/pandemics, although the effectiveness of licensed vaccines is rather limited due to the constant mutations of influenza virus antigenic characteristics. The available anti-influenza drugs are still restricted and there is an increasing viral resistance to these compounds, thus highlighting the need for research and development of new antiviral drugs. In this work, two semisynthetic derivatives of digitoxigenin, namely C10 (3ß-((N-(2-hydroxyethyl)aminoacetyl)amino-3-deoxydigitoxigenin) and C11 (3ß-(hydroxyacetyl)amino-3-deoxydigitoxigenin), showed anti-influenza A virus activity by affecting the expression of viral proteins at the early and late stages of replication cycle, and altering the transcription and synthesis of new viral proteins, thereby inhibiting the formation of new virions. Such antiviral action occurred due to the interference in the assembly of viral polymerase, resulting in an impaired polymerase activity and, therefore, reducing viral replication. Confirming the in vitro results, a clinically relevant ex vivo model of influenza virus infection of human tumor-free lung tissues corroborated the potential of these compounds, especially C10, to completely abrogate influenza A virus replication at the highest concentration tested (2.0 µM). Taken together, these promising results demonstrated that C10 and C11 can be considered as potential new anti-influenza drug candidates.
Asunto(s)
Antivirales/farmacología , Cardenólidos/farmacología , Virus de la Influenza A/efectos de los fármacos , Gripe Humana/tratamiento farmacológico , ARN Polimerasa Dependiente del ARN/antagonistas & inhibidores , Antivirales/química , Cardenólidos/química , Humanos , Conformación Molecular , ARN Polimerasa Dependiente del ARN/metabolismo , Replicación Viral/efectos de los fármacosRESUMEN
BACKGROUND: ERAS guidelines recommend early removal of urinary drainage after colorectal surgery to reduce the risk of catheter-associated urinary tract infections (CAUTI). Another recommendation is the postoperative use of epidural analgesia (EA). In many types of surgery, EA was shown to increase the risk of postoperative urinary retention (POUR). This study determines the impact of early urinary catheter removal on the incidence of POUR and CAUTI under EA after colorectal surgery. METHODS: Eligible patients were scheduled for colorectal surgery within the local ERAS protocol between April 2015 and September 2016. Urinary drainage was removed on the first postoperative day while EA was still in place (early removal group (ER)). The incidences of POUR and CAUTIs were recorded prospectively. Results were compared with a historical control (CG), which was operated between October 2013 and March 2015. RESULTS: POUR occurred significantly more often in the ER (ER 7.8%; CG 2.6%), while CAUTIs were significantly less frequent in the ER (13.8%) compared with the CG (30.4%). Patients who developed POUR were characterised by a significantly higher rate of abdominoperineal resections, by a higher frequency of rectal cancer, and a higher male-to-female ratio compared with patients who did not develop POUR. CONCLUSION: Early removal of urinary drainage after colorectal surgery while EA is still in place is feasible; it reduces the incidence of CAUTI but increases the risk of POUR. Thus, screening for POUR in patients with failure to void after six to 8 h is mandatory under these clinical conditions.
Asunto(s)
Analgesia Epidural , Remoción de Dispositivos , Cuidados Posoperatorios , Complicaciones Posoperatorias/prevención & control , Cateterismo Urinario , Retención Urinaria/prevención & control , Infecciones Urinarias/prevención & control , Anciano , Estudios de Factibilidad , Femenino , Alemania , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de RiesgoRESUMEN
Although it is well established that the release of HCV (hepatitis C virus) occurs through the secretory pathway, many aspects concerning the control of this process are not yet fully understood. α-Taxilin was identified as a novel binding partner of syntaxin-4 and of other members of the syntaxin family, which are part of SNARE (soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptor) complexes and so are involved in intracellular vesicle traffic. Since α-taxilin prevents t-SNARE (target SNARE) formation by binding exclusively to free syntaxin-4, it exerts an inhibitory effect on the vesicular transport. HCV-replicating Huh7.5 cells and HCV-infected primary human hepatocytes and liver samples of patients suffering from chronic HCV contain significantly less α-taxilin compared with the controls. HCV impairs the expression of α-taxilin via NS5A-dependent interruption of the Raf/MEK [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase] signal transduction cascade. Moreover, the half-life of α-taxilin is significantly reduced in HCV-replicating cells. Whereas modulation of α-taxilin expression does not significantly affect genome replication, the overexpression of α-taxilin prevents the release of HCV. In contrast with this, silencing of α-taxilin expression leads to increased release of infectious viral particles. This is due to the negative effect of α-taxilin on t-SNARE formation that leads to impaired vesicular trafficking. Accordingly, overexpression of the t-SNARE component syntaxin-4 increases release of HCV, whereas silencing leads to an impaired release. These data identify α-taxilin as a novel factor that controls the release of HCV and reveal the mechanism by which HCV controls the activity of α-taxilin.
Asunto(s)
Hepacivirus/metabolismo , Proteínas de Transporte Vesicular/biosíntesis , Células Hep G2 , Humanos , Vesículas Sinápticas/metabolismoRESUMEN
Host targeting antiviral drugs (HTA) are directed against cellular mechanisms which can be exploited by viruses. These mechanisms are essential for viral replication, because missing functions cannot be compensated by the virus. However, this assumption needs experimental proof. Here we compared the HTA Zapnometinib (ZMN), with direct acting antivirals (DAA) (Remdesivir (RDV), Molnupiravir (MPV), Nirmatrelvir (NTV), Ritonavir (RTV), Paxlovid PAX)), in terms of their potency to induce reduced drug susceptibilities in SARS-CoV-2. During serial passage of δ-B1.617.2 adaptation to all DAAs occurred, while the inhibitory capacity of ZMN was not altered. Known single nucleotide polymorphisms (SNPs) responsible for partial resistances were found for RDV, NTV and PAX. Additionally, the high mutagenic potential of MPV was confirmed and decreased drug efficacies were found for the first time. Reduced DAA efficacy did not alter the inhibitory potential of ZMN. These results show that ZMN confers a high barrier towards the development of viral resistance and has the potential to act against partially DAA-insensitive viruses.
Asunto(s)
COVID-19 , Citidina/análogos & derivados , Hepatitis C Crónica , Hidroxilaminas , Humanos , Antivirales , SARS-CoV-2 , RitonavirRESUMEN
Cold atmospheric plasma (CAP) has shown promising potential in promoting wound healing. This case report presents the successful application of CAP in a 42-year-old female patient with extensive wound healing disorders and superinfections following the excision of an abscess in the left thoracic region. After several failed split skin graft attempts, the implementation of CAP led to significant improvements in wound healing. This report highlights the wound healing-promoting effects of CAP and discusses its potential mechanisms of action.
RESUMEN
The recent COVID-19 pandemic again highlighted the urgent need for broad-spectrum antivirals, both for therapeutic use in acute viral infection and for pandemic preparedness in general. The targeting of host cell factors hijacked by viruses during their replication cycle presents one possible strategy for development of broad-spectrum antivirals. By inhibiting the Raf/MEK/ERK signaling pathway, a central kinase cascade of eukaryotic cells, which is being exploited by numerous viruses of different virus phyla, the small-molecule MEK inhibitor zapnometinib has the potential to address this need. We here performed a side-by-side comparison of the antiviral efficacy of zapnometinib against IAV and SARS-CoV-2 to determine the concentration leading to 50% of its effect on the virus (EC50) and the concentration leading to 50% reduction of ERK phosphorylation (IC50) in a comparable manner, using the same experimental conditions. Our results show that the EC50 value and IC50 value of zapnometinib are indeed lower for IAV compared to SARS-CoV-2 using one representative strain for each. The results suggest that IAV's replication has a stronger dependency on an active Raf/MEK/ERK pathway and, thus, that IAV is more susceptible to treatment with zapnometinib than SARS-CoV-2. With zapnometinib's favorable outcome in a recent phase II clinical trial in hospitalized COVID-19 patients, the present results are even more promising for an upcoming phase II clinical trial in severe influenza virus infection.
Asunto(s)
COVID-19 , Virus de la Influenza A , Gripe Humana , Humanos , Sistema de Señalización de MAP Quinasas , SARS-CoV-2 , Gripe Humana/tratamiento farmacológico , Pandemias , Replicación Viral , Transducción de Señal , Antivirales/farmacología , Quinasas de Proteína Quinasa Activadas por MitógenosRESUMEN
SARS-CoV-2 is the causative agent of the immune response-driven disease COVID-19 for which new antiviral and anti-inflammatory treatments are urgently needed to reduce recovery time, risk of death and long COVID development. Here, we demonstrate that the immunoregulatory kinase p38 MAPK is activated during viral entry, mediated by the viral spike protein, and drives the harmful virus-induced inflammatory responses. Using primary human lung explants and lung epithelial organoids, we demonstrate that targeting p38 signal transduction with the selective and clinically pre-evaluated inhibitors PH-797804 and VX-702 markedly reduced the expression of the pro-inflammatory cytokines IL6, CXCL8, CXCL10 and TNF-α during infection, while viral replication and the interferon-mediated antiviral response of the lung epithelial barrier were largely maintained. Furthermore, our results reveal a high level of drug synergism of both p38 inhibitors in co-treatments with the nucleoside analogs Remdesivir and Molnupiravir to suppress viral replication of the SARS-CoV-2 variants of concern, revealing an exciting and novel mode of synergistic action of p38 inhibition. These results open new avenues for the improvement of the current treatment strategies for COVID-19.
Asunto(s)
Antivirales , COVID-19 , Inflamación , Síndrome Post Agudo de COVID-19 , SARS-CoV-2 , Proteínas Quinasas p38 Activadas por Mitógenos , Humanos , Antivirales/farmacología , Antivirales/uso terapéutico , COVID-19/complicaciones , Inflamación/tratamiento farmacológico , Inflamación/virología , Pulmón , Transducción de SeñalRESUMEN
Modern determination techniques for pesticides must yield identification quickly with high confidence for timely enforcement of tolerances. A protocol for the collection of liquid chromatography (LC) electrospray ionization (ESI)-quadruple linear ion trap (Q-LIT) mass spectrometry (MS) library spectra was developed. Following the protocol, an enhanced product ion (EPI) library of 240 pesticides was developed by use of spectra collected from two laboratories. A LC-Q-LIT-MS workflow using scheduled multiple reaction monitoring (sMRM) survey scan, information-dependent acquisition (IDA) triggered collection of EPI spectra, and library search was developed and tested to identify the 240 target pesticides in one single LC-Q-LIT MS analysis. By use of LC retention time, one sMRM survey scan transition, and a library search, 75-87% of the 240 pesticides were identified in a single LC/MS analysis at fortified concentrations of 10 ng/g in 18 different foods. A conventional approach with LC-MS/MS using two MRM transitions produced the same identifications and comparable quantitative results with the same incurred foods as the LC-Q-LIT using EPI library search, finding 1.2-49 ng/g of either carbaryl, carbendazim, fenbuconazole, propiconazole, or pyridaben in peaches; carbendazim, imazalil, terbutryn, and thiabendazole in oranges; terbutryn in salmon; and azoxystrobin in ginseng. Incurred broccoli, cabbage, and kale were screened with the same EPI library using three LC-Q-LIT and a LC-quadruple time-of-flight (Q-TOF) instruments. The library search identified azoxystrobin, cyprodinil, fludioxinil, imidacloprid, metalaxyl, spinosyn A, D, and J, amd spirotetramat with each instrument. The approach has a broad application in LC-MS/MS type targeted screening in food analysis.
Asunto(s)
Análisis de los Alimentos/métodos , Plaguicidas/análisis , Espectrometría de Masa por Ionización de Electrospray/métodos , Espectrometría de Masas en Tándem/métodos , Cromatografía Liquida , Bases de Datos Factuales , Iones/análisisRESUMEN
The coronavirus disease 2019 (COVID-19) represents a global public health burden. In addition to vaccination, safe and efficient antiviral treatment strategies to restrict the viral spread within the patient are urgently needed. An alternative approach to a single-drug therapy is the combinatory use of virus- and host-targeted antivirals, leading to a synergistic boost of the drugs' impact. In this study, we investigated the property of the MEK1/2 inhibitor ATR-002's (zapnometinib) ability to potentiate the effect of direct-acting antivirals (DAA) against SARS-CoV-2 on viral replication. Treatment combinations of ATR-002 with nucleoside inhibitors Molnupiravir and Remdesivir or 3C-like protease inhibitors Nirmatrelvir and Ritonavir, the ingredients of the drug Paxlovid, were examined in Calu-3 cells to evaluate the advantage of their combinatory use against a SARS-CoV-2 infection. Synergistic effects could be observed for all tested combinations of ATR-002 with DAAs, as calculated by four different reference models in a concentration range that was very well-tolerated by the cells. Our results show that ATR-002 has the potential to act synergistically in combination with direct-acting antivirals, allowing for a reduction in the effective concentrations of the individual drugs and reducing side effects.
RESUMEN
Several studies have pointed to retinal involvement in COVID-19, yet many questions remain regarding the ability of SARS-CoV-2 to infect and replicate in retinal cells and its effects on the retina. Here, we have used human pluripotent stem cell-derived retinal organoids to study retinal infection by SARS-CoV-2. Indeed, SARS-CoV-2 can infect and replicate in retinal organoids, as it is shown to infect different retinal lineages, such as retinal ganglion cells and photoreceptors. SARS-CoV-2 infection of retinal organoids also induces the expression of several inflammatory genes, such as interleukin 33, a gene associated with acute COVID-19 and retinal degeneration. Finally, we show that the use of antibodies to block ACE2 significantly reduces SARS-CoV-2 infection of retinal organoids, indicating that SARS-CoV-2 infects retinal cells in an ACE2-dependent manner. These results suggest a retinal involvement in COVID-19 and emphasize the need to monitor retinal pathologies as potential sequelae of "long COVID."
Asunto(s)
COVID-19 , Enzima Convertidora de Angiotensina 2 , COVID-19/complicaciones , Humanos , Organoides/metabolismo , Retina , Células Ganglionares de la Retina , SARS-CoV-2 , Síndrome Post Agudo de COVID-19RESUMEN
For almost two years, the COVID-19 pandemic has constituted a major challenge to human health, particularly due to the lack of efficient antivirals to be used against the virus during routine treatment interventions. Multiple treatment options have been investigated for their potential inhibitory effect on SARS-CoV-2. Natural products, such as plant extracts, may be a promising option, as they have shown an antiviral activity against other viruses in the past. Here, a quantified extract of Hypericum perforatum was tested and found to possess a potent antiviral activity against SARS-CoV-2. The antiviral potency of the extract could be attributed to the naphtodianthrones hypericin and pseudohypericin, in contrast to other tested ingredients of the plant material, which did not show any antiviral activity. Hypericum perforatum and its main active ingredient hypericin were also effective against different SARS-CoV-2 variants (Alpha, Beta, Delta, and Omicron). Concerning its mechanism of action, evidence was obtained that Hypericum perforatum and hypericin may hold a direct virus-blocking effect against SARS-CoV-2 virus particles. Taken together, the presented data clearly emphasize the promising antiviral activity of Hypericum perforatum and its active ingredients against SARS-CoV-2 infections.
RESUMEN
We report the use of electrospray ionization tandem mass spectrometry (ESI-MS/MS) as a tool for rapid screening of structurally related chemicals toward oligonucleotides using the binding of five bromobenzoquinones with single-stranded (ss) and double-stranded (ds) oligonucleotides (ODNs) as a model. We found that these compounds interact differentially with oligonucleotides depending on the extent of their bromination and methylation. Three dibromobenzoquinones, 2,6-dibromo-1,4-benzoquinone (2,6-DBBQ), 2,5-dibromo-1,4-benzoquinone (2,5-DBBQ), and 2,5-dimethyl-3,6-dibromo-1,4-benzoquinone (DMDBBQ), bound to ssODN to form 1:1 adducts, and the binding constant of DMDBBQ bound to ssODN was 100-fold lower than those of 2,6-DBBQ and 2,5-DBBQ to ssODN, indicating that methyl groups hindered interactions of the bromoquinones with ODNs. Collision-induced dissociation (CID) of the 1:1 and 1:2 adducts of ODN with 2,6-DBBQ and 2,5-DBBQ demonstrated neutral loss of DBBQ and charge separations. Incubation of two tetrabromobenzoquinones (TBBQ), 2,3,5,6-tetrabromo-1,4-benzoquinone and 3,4,5,6-tetrabromo-1,2-benzoquinone, with the same ODNs did not form any adducts of TBBQ with ssODN or dsODN; however, bromide-ODNs were detected. Fragmentation of the bromide-ODN adducts showed loss of the HBr molecule, supporting the presence of bromide on ODNs. High-resolution MS and MS/MS analysis of the mixtures of dinucleotides (AA, GG, CC, and TT) and TBBQ confirmed the presence of bromide on the dinucleotides, supporting the transfer of bromide to ODNs through interaction with TBBQ. This study presents evidence of differential interactions of structurally related bromo and methyl-benzoquinones with oligonucleotides and demonstrates a potential application of ESI-MS/MS analysis of chemical interactions with ODN for rapid screening of the reactivity of other structurally related environmental contaminants toward DNA.
Asunto(s)
Benzoquinonas/química , ADN/química , Halogenación , Oligodesoxirribonucleótidos/química , Espectrometría de Masa por Ionización de Electrospray , Espectrometría de Masas en Tándem , Aductos de ADN , Metilación , Contaminantes Químicos del Agua , Purificación del AguaRESUMEN
Host shutoff in influenza A virus (IAV) infection is a key process contributing to viral takeover of the cellular machinery and resulting in the downregulation of host gene expression. Analysis of nascently transcribed RNA in a cellular model that allows the functional induction of NS1 demonstrates that NS1 suppresses host transcription. NS1 inhibits the expression of genes driven by RNA polymerase II as well as RNA polymerase I-driven promoters, but not by the noneukaryotic T7 polymerase. Additionally, transcriptional termination is deregulated in cells infected with wild-type IAV. The NS1 effector domain alone is able to mediate both effects, whereas NS1 mutant GLEWN184-188RFKRY (184-188) is not. Overexpression of CPSF30 counteracts NS1-mediated inhibition of RNA polymerase II-driven reporter gene expression, but knockdown of CPSF30 expression does not attenuate gene expression. Although NS1 is associated with nuclear chromatin, superresolution microscopy demonstrates that NS1 does not colocalize with genomic DNA. Moreover, NS1 mutants and NS1 fusion proteins, unable to associate with nuclear chromatin and displaying an altered subcellular distribution are still able to attenuate reporter gene expression. However, tethering NS1 artificially to the cytoskeleton results in the loss of reporter gene inhibition. A NS1 deficient in both native nuclear localization signals (NLS) is able to inhibit gene expression as effective as wild-type NS1 when a synthetic NLS relocates it to specific structures of the nucleus. Colocalization experiments and reporter gene cotransfection experiments with a NS1 fusion guiding it to nuclear speckles suggest that the presence of NS1 in nuclear speckles seems to be essential for host shutoff. IMPORTANCE We investigated the role of IAV nonstructural protein 1 NS1 in host gene shutoff-a central feature of IAV replication. We demonstrate that the effector domain of NS1 alone mediates host gene shutoff by inhibition of host transcription and by deregulation of the polyadenylation (polyA) signal-mediated 3' termination of host transcription. NS1 mutated in amino acids 184 to 188 fails to shut off host gene expression. Knockdown of CPSF30 does not result in transcriptional attenuation. By analyzing the subcellular localization of modified NS1 proteins and relating these data to their ability to inhibit reporter gene expression, we show for the first time that the presence of NS1 in granular structures of the nucleus-representing most likely nuclear speckles-seems to be essential to mediate host gene shutoff. Thus, our data present so far unknown insights into the molecular and spatial requirements needed for IAV-NS1-mediated host shutoff.
Asunto(s)
Núcleo Celular/virología , Subtipo H7N7 del Virus de la Influenza A/metabolismo , Gripe Humana/genética , Gripe Humana/virología , Transcripción Genética , Proteínas no Estructurales Virales/química , Proteínas no Estructurales Virales/metabolismo , Núcleo Celular/genética , Núcleo Celular/metabolismo , Factor de Especificidad de Desdoblamiento y Poliadenilación/genética , Factor de Especificidad de Desdoblamiento y Poliadenilación/metabolismo , Interacciones Huésped-Patógeno , Humanos , Subtipo H7N7 del Virus de la Influenza A/genética , Gripe Humana/metabolismo , Dominios Proteicos , ARN Polimerasa II/genética , ARN Polimerasa II/metabolismo , Proteínas no Estructurales Virales/genéticaRESUMEN
BACKGROUND: Persistent urachal sinuses or fistulas are rare but may potentially cause various symptoms and lead to repeated operations. Both laparoscopic and open surgery have been used for the resection of the urachus. METHODS: This report describes the first case of an external urachal fistula with recurrent infections and discharge of the umbilicus treated by complete resection using single-incision laparoscopic surgery (SILS). This involved a laparoscopic single-incision three-trocar-technique, leaving the infected site of the umbilicus untouched. RESULTS: Healing of the umbilicus was uneventful and complete. To date, the authors have not seen any recurrence of the fistula or its symptoms. CONCLUSIONS: Remnants of the urachus should be considered in cases of recurrent infections or discharge of the umbilicus. The SILS procedure is an excellent option for the radical resection of the remnant urachus. Compared with the standard laparoscopic approach, it requires only one incision, decreasing the risks compared with those of several trocars. At the same time, the patient benefits from the better cosmetic result.
Asunto(s)
Laparoscopía/métodos , Quiste del Uraco/cirugía , Humanos , Masculino , Recurrencia , Ultrasonografía , Ombligo/cirugía , Quiste del Uraco/diagnóstico por imagen , Uraco/cirugía , Adulto JovenRESUMEN
BACKGROUND: In response to a need for accurate and reliable methods for food allergen regulatory compliance, a method for the detection and quantitation of whole egg, whole milk, peanut, and hazelnut in eight food matrices was developed and evaluated in a single-laboratory validation. The matrices include cookies, cookie dough, bread, breakfast cereal, salad dressing, ice cream, and red wine. OBJECTIVE: The method was compared with Standard Method Performance Requirements (SMPR) 2016.002 established by the AOAC Stakeholder Panel on Strategic Food Analytical Methods. METHODS: The method involves tryptic digestion of allergen proteins in food matrices incurred or spiked with allergen standards [reference materials (RMs), Standard RMs (SRMs), or in-house prepared standard] and uses labeled peptide internal standards. LC-tandem MS analysis of the signature tryptic peptides of the four allergens is performed using multiple reaction monitoring. RESULTS: For 10 allergen/matrix combinations, the method demonstrated adequate sensitivity with a minimum quantitation limit of 3 mg/kg for whole egg and 10 mg/kg for milk, peanut, and hazelnut allergens. Repeatability precision across 3 days of analyses was <17% with analytical range of 10-1000 mg/kg. Recovery from incurred and spiked matrix-matched standards varied from 60 to 118%. CONCLUSIONS: The method met the minimum performance requirements of SMPR 2016.002 for whole egg in cookies, bread, cookie dough, and salad dressing; whole milk in cookies and red wine; peanut in breakfast cereal; and hazelnut in cookies. HIGHLIGHTS: The ERP determined that the data presented met the SMPR and accordingly recommended the method to be granted First Action status. In September 2017, the Official Methods Board approved the method as First Action.