Hepatitis C virus cell-cell transmission and resistance to direct-acting antiviral agents

Hepatitis C virus (HCV) is transmitted between hepatocytes via classical cell entry but also uses direct cell-cell transfer to infect neighboring hepatocytes. Viral cell-cell transmission has been shown to play an important role in viral persistence allowing evasion from neutralizing antibodies. In contrast, the role of HCV cell-cell transmission for antiviral resistance is unknown. Aiming to address this question we investigated the phenotype of HCV strains exhibiting resistance to direct-acting antivirals (DAAs) in state-of-the-art model systems for cell-cell transmission and spread. Using HCV genotype 2 as a model virus, we show that cell-cell transmission is the main route of viral spread of DAA-resistant HCV. Cell-cell transmission of DAA-resistant viruses results in viral persistence and thus hampers viral eradication. We also show that blocking cell-cell transmission using host-targeting entry inhibitors (HTEIs) was highly effective in inhibiting viral dissemination of resistant genotype 2 viruses. Combining HTEIs with DAAs prevented antiviral resistance and led to rapid elimination of the virus in cell culture model. In conclusion, our work provides evidence that cell-cell transmission plays an important role in dissemination and maintenance of resistant variants in cell culture models. Blocking virus cell-cell transmission prevents emergence of drug resistance in persistent viral infection including resistance to HCV DAAs

Six months of multiwavelength follow-up of the tidal disruption candidate ASASSN-14li and implied TDE rates from ASAS-SN

We present ground-based and Swift photometric and spectroscopic observations of the candidate tidal disruption event (TDE) ASASSN-14li, found at the center of PGC043234 (d ' 90 Mpc) by the All-Sky Automated Survey for SuperNovae (ASAS-SN). The source had a peak bolometric luminosity of L ' 1044 ergs

Viral Kinetics Suggests a Reconciliation of the Disparate Observations of the Modulation of Claudin-1 Expression on Cells Exposed to Hepatitis C Virus

The tight junction protein claudin-1 (CLDN1) is necessary for hepatitis C virus (HCV) entry into target cells. Recent studies have made disparate observations of the modulation of the expression of CLDN1 on cells following infection by HCV. In one study, the mean CLDN1 expression on cells exposed to HCV declined, whereas in another study HCV infected cells showed increased CLDN1 expression compared to uninfected cells. Consequently, the role of HCV in modulating CLDN1 expression, and hence the frequency of cellular superinfection, remains unclear. Here, we present a possible reconciliation of these disparate observations. We hypothesized that viral kinetics and not necessarily HCV-induced receptor modulation underlies these disparate observations. To test this hypothesis, we constructed a mathematical model of viral kinetics in vitro that mimicked the above experiments. Model predictions provided good fits to the observed evolution of the distribution of CLDN1 expression on cells following exposure to HCV. Cells with higher CLDN1 expression were preferentially infected and outgrown by cells with lower CLDN1 expression, resulting in a decline of the mean CLDN1 expression with time. At the same time, because the susceptibility of cells to infection increased with CLDN1 expression, infected cells tended to have higher CLDN1 expression on average than uninfected cells. Our study thus presents an explanation of the disparate observations of CLDN1 expression following HCV infection and points to the importance of considering viral kinetics in future studies of receptor expression on cells exposed to HCV

Discovery and Observations of the Unusually Luminous Type-Defying II-P/II-L Supernova ASASSN-13co

We present photometric and spectroscopic observations of ASASSN-13co, an unusually luminous Type II supernova and the first core-collapse supernova discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN). First detection of the supernova was on UT 2013 August 29 and the data presented span roughly 3.5 months after discovery. We use the recently developed model from Pejcha & Prieto (2015) to model the multi-band light curves of ASASSN-13co and derive the bolometric luminosity curve. We compare ASASSN-13co to other Type II supernovae to show that it was unusually luminous for a Type II supernova and that it exhibited an atypical light curve shape that does not cleanly match that of either a standard Type II-L or Type II-P supernova

Effectiveness of cricoid pressure in preventing gastric aspiration during rapid sequence intubation in the emergency department: study protocol for a randomised controlled trial

<p>Abstract</p> <p>Background</p> <p>Cricoid pressure is considered to be the gold standard means of preventing aspiration of gastric content during Rapid Sequence Intubation (RSI). Its effectiveness has only been demonstrated in cadaveric studies and case reports. No randomised controlled trials comparing the incidence of gastric aspiration following emergent RSI, with or without cricoid pressure, have been performed. If improperly applied, cricoid pressure increases risk to the patient. The clinical significance of aspiration in the emergency department is unknown. This randomised controlled trial aims to; 1. Compare the application of the 'ideal" amount of force (30 - 40 newtons) to standard, unmeasured cricoid pressure and 2. Determine the incidence of clinically defined aspiration syndromes following RSI using a fibrinogen degradation assay previously described.</p> <p>Methods/design</p> <p>212 patients requiring emergency intubation will be randomly allocated to either control (unmeasured cricoid pressure) or intervention groups (30 - 40 newtons cricoid pressure). The primary outcome is the rate of aspiration of gastric contents (determined by pepsin detection in the oropharyngeal/tracheal aspirates or treatment for aspiration pneumonitis up to 28 days post-intubation). Secondary outcomes are; correlation between aspiration and lowest pre-intubation Glasgow Coma Score, the relationship between detection of pepsin in trachea and development of aspiration syndromes, complications associated with intubation and grade of the view on direct largyngoscopy.</p> <p>Discussion</p> <p>The benefits and risks of cricoid pressure application will be scrutinised by comparison of the incidence of aspiration and difficult or failed intubations in each group. The role of cricoid pressure in RSI in the emergency department and the use of a pepsin detection as a predictor of clinical aspiration will be evaluated.</p> <p>Trial registration</p> <p>Australian New Zealand Clinical Trials Registry (ANZCTR): <a href="http://www.anzctr.org.au/ACTRN12611000587909.aspx">ACTRN12611000587909</a></p

Novel Small-Molecule Inhibitors of Hepatitis C Virus Entry Block Viral Spread and Promote Viral Clearance in Cell Culture

Combinations of direct-acting anti-virals offer the potential to improve the efficacy, tolerability and duration of the current treatment regimen for hepatitis C virus (HCV) infection. Viral entry represents a distinct therapeutic target that has been validated clinically for a number of pathogenic viruses. To discover novel inhibitors of HCV entry, we conducted a high throughput screen of a proprietary small-molecule compound library using HCV pseudoviral particle (HCVpp) technology. We independently discovered and optimized a series of 1,3,5-triazine compounds that are potent, selective and non-cytotoxic inhibitors of HCV entry. Representative compounds fully suppress both cell-free virus and cell-to-cell spread of HCV in vitro. We demonstrate, for the first time, that long term treatment of an HCV cell culture with a potent entry inhibitor promotes sustained viral clearance in vitro. We have confirmed that a single amino acid variant, V719G, in the transmembrane domain of E2 is sufficient to confer resistance to multiple compounds from the triazine series. Resistance studies were extended by evaluating both the fusogenic properties and growth kinetics of drug-induced and natural amino acid variants in the HCVpp and HCV cell culture assays. Our results indicate that amino acid variations at position 719 incur a significant fitness penalty. Introduction of I719 into a genotype 1b envelope sequence did not affect HCV entry; however, the overall level of HCV replication was reduced compared to the parental genotype 1b/2a HCV strain. Consistent with these findings, I719 represents a significant fraction of the naturally occurring genotype 1b sequences. Importantly, I719, the most relevant natural polymorphism, did not significantly alter the susceptibility of HCV to the triazine compounds. The preclinical properties of these triazine compounds support further investigation of entry inhibitors as a potential novel therapy for HCV infection

Virologie / Bakteriologie / Mykologie

141 - Effizienz von Kaliumhypochlorit zur Inaktivierung ausgewählter pilzlicher, bakterieller und viraler PflanzenkrankheitserregerEfficancy of Potassium Hypochlorite (KClO) to inactivate selected plant pathogenic fungi, bacteria and virusesMarlon-Hans Rodríguez, Martina Bandte, Gerhard Fischer, Carmen Büttner142 - Eignung von elektrolytisch generiertem Kaliumhypochlorit zur Inaktivierung von Pflanzenviren in rezirkulierender Nährlösungen im Gewächshausanbau von TomatenAbility of electrolysed produced Potassium Hypochlorite (KClO) to inactivate plant viruses in recirculating nutrient solutions in greenhouse production of tomatosJanine Paulke, Martina Bandte, Carmen Büttner143 - Ultrafiltration und Ultrazentrifugation zur Konzentrierung von Pflanzenviren in NährlösungUltrafiltration and ultracentrifugation as tools to concentrate plant viruses in nutrient solutionJanina Vincenz, Martina Bandte, Carmen Büttner144 - Reinigung doppelsträngiger RNA in Verbindung mit Hochdurchsatzsequenzierung als Werkzeug zum Nachweis von RNA Viren in PflanzenThe combination of double-stranded RNA isolation and deep sequencing as an unspecific diagnostic tool to assess the presence of RNA viruses in plantsTill Lesker, Paul Rentz, Edgar Maiss145 - Impact of silica supplementation on virus infected cucumber culturesRolle der Kieselsäureapplikation Virus infizierter GurkenkulturenSabine Holz, Grzegorz Bartoszewski , Michael Kube, Carmen Büttner146 - Untersuchungen zum Auftreten des Arabis mosaic virus in Birken aus Rovaniemi (Finnland) mit Virus-spezifischen SymptomenInvestigations on the occurence of Arabis mosaic virus in birches from Rovaniemi (Finland) with virus-specific symptomsRichard Pauwels, Markus Rott, Susanne von Bargen, Carmen Büttner147 - Cherry leaf roll virus in Betula spp. in Finland: what do we know about its population diversity?Cherry leaf roll virus in Birken-Arten in Finnland: Was wissen wir über die Populationsdiversität?A. Rumbou, S. von Bargen, M. Rott, R. Jalkanen, C. Büttner148 - Viruserkrankungen im WeinbauViroses in viticultureHenriette Gruber, Patricia Bohnert, Christiane Rieger149 - Molecular analysis of Tobacco rattle virus isolates from potatoes in various parts of GermanyKerstin Lindner, Renate Koenig150 - Detektion und Diversität des European mountain ash ringspot-associated virus (EMARaV) in Ebereschen (Sorbus aucuparia L.) in NorwegenDetection and variability of European mountain ash ringspot-associated virus (EMARaV) in Sorbus aucuparia L. in NorwayTheresa Büttner, Jenny Robel, Hans-Peter Mühlbach, Susanne von Bargen, Carmen Büttner151 - Charakterisierung des European mountain ash ringspot-associated virus (EMARaV) in Mehlbeerenarten (Sorbus spp.)Characterization of the European mountain ash ringspot-associated virus (EMARaV) in whitebeam species (Sorbus spp.)Luisa Dieckmann, Jenny Robel, Susanne von Bargen, Carmen Büttner152 - Vollständige Genomsequenz eines Carrot virus S Isolates aus Meerfenchel aus SpanienW. Menzel, P. Menzel, S. Winter153 - Nachweis und vollständige Sequenzierung eines Carla- und eines Potex-virus aus Epiphyullum spec.Detection and complete sequence of a Carla- and Potexvirus in Epiphyllum spec.Edgar Maiss, Paul Rentz, Annette Hohe, Rosa Herbst154 - Analysis of mixed populations of latent viruses of apple and rubbery wood disease of apple using new generation sequencingAnalyse von Mischpopulationen latenter Apfelviren und der Gummiholzkrankheit an Apfel mittels HochdurchsatzsequenzierungVladimir Jakovljevic, Patricia Otten, Jonathon Blake, Wilhelm Jelkmann155 - Experiments on transmission of viroids under glass and longevity of viroid RNA in detached leaves under different storage conditionsThi Thu Vo, Heinz-Wilhelm Dehne, Stephan Winter, Joachim Hamacher156 - Phytoplasmen in Schleswig-HolsteinPhytoplasmas in the state of Schleswig-HolsteinG. Henkel, C. Willmer, M. Wunderlich, B. Golecki157 . Phytoplasmen verändern das Dufststoffbouquet ihres pflanzlichen LebensraumsPlant volatile emission is affected by phytoplasma infectionMargit Rid, Kai Lukat, Svenja Hoferer, Jürgen Gross159 - Ist das Wurzelbild ein Sortierungsmerkmal für durch Candidatus Phytoplasma pyri verursachten Birnenverfall?Is the root file a sorting feature for Pear decline caused by Canditatus Phytoplama pyri?Georg Henkel, Claudia Willmer, Bernd Kaland, Bettina Golecki160 - Die Bedeutung von β-Caryophyllen als Lockstoff für die Apfeltriebsucht übertragende Blattsaugerart Cacopsylla pictaThe impact of β-caryophyllene as attractant for the Apple Proliferation transmitting insect Cacopsylla pictaConstanze Mesca, Svenja Hoferer, Jürgen Gross161 - Echte Mehltauarten an Beet- und BalkonpflanzenSpecies of powdery mildews on bedding plantsUlrike Brielmaier-Liebetanz162 - Echter Mehltau an Petersilie – Untersuchungen zum WirtspflanzenspektrumPowdery Mildew of Parsley – studies on the host rangePeggy Marx, Ute Gärber163 - Falscher Mehltau an Petersilie – Untersuchungen zum Wirtspflanzenspektrum und molekularbiologische CharakterisierungDowny mildew of parsley – studies on the host range and molecular characterizationGabriele Leinhos, Hermann-Josef Krauthausen, Frank Brändle164 - Welkekrankheit an Euonymus japonicaWilt disease on Euonymus japonicaUlrike Brielmaier-Liebetanz, Roswitha Ulrich, Stefan Wagner, Sabine Werres165 - Taxonomische Analyse der mikrobiellen Gemeinschaft von Zuckerrüben unter unterschiedlichen Lagerbedingungen mittels Hochdurchsatz-Amplikonsequenzierung von unterschiedlichen MarkergenenTaxonomic analysis of the microbial community in stored sugar beets using highthroughput sequencing of different marker genesSebastian Liebe, Daniel Wibberg, Anika Winkler, Alfred Pühler, Andreas Schlüter, Mark Varrelmann166 - Molecular characterization of a novel mycovirus found in Rhizoctonia solani AG 2-2IIIBMolekulare Charakterisierung eines neuen Mycovirus aus Rhizoctonia solani AG 2-2 IIIBAnika Bartholomäus, Mark Varrelman