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Summary The mRNA-based BNT162b2 vaccine from Pfizer/BioNTech was the first registered COVID-19 vaccine and has been shown to be up to 95% effective in preventing SARS-CoV-2 infections. Little is known about the broad effects of the new class of mRNA vaccines, especially whether they have combined effects on innate and adaptive immune responses. Here we confirmed that BNT162b2 vaccination of healthy individuals induced effective humoral and cellular immunity against several SARS-CoV-2 variants. Interestingly, however, the BNT162b2 vaccine also modulated the production of inflammatory cytokines by innate immune cells upon stimulation with both specific (SARS-CoV-2) and non-specific (viral, fungal and bacterial) stimuli. The response of innate immune cells to TLR4 and TLR7/8 ligands was lower after BNT162b2 vaccination, while fungi-induced cytokine responses were stronger. In conclusion, the mRNA BNT162b2 vaccine induces complex functional reprogramming of innate immune responses, which should be considered in the development and use of this new class of vaccines.
F. Konstantin Föhse; Büsranur Geckin; Gijs J. Overheul; Josephine van de Maat; Gizem Kilic; Ozlem Bulut; Helga Dijkstra; Heidi Lemmers; S. Andrei Sarlea; Maartje Reijnders; Jacobien Hoogerwerf; Jaap Ten Oever; Elles Simonetti; Frank L. van de Veerdonk; Leo A.B. Joosten; Bart L. Haagmans; Reinout van Crevel; Yang Li; Ronald P. van Rij; Corine GeurtsvanKessel; Marien I. de Jonge; Jorge Domínguez-Andrés; Mihai G. Netea. The BNT162b2 mRNA vaccine against SARS-CoV-2 reprograms both adaptive and innate immune responses. 2021, 1 .
AMA StyleF. Konstantin Föhse, Büsranur Geckin, Gijs J. Overheul, Josephine van de Maat, Gizem Kilic, Ozlem Bulut, Helga Dijkstra, Heidi Lemmers, S. Andrei Sarlea, Maartje Reijnders, Jacobien Hoogerwerf, Jaap Ten Oever, Elles Simonetti, Frank L. van de Veerdonk, Leo A.B. Joosten, Bart L. Haagmans, Reinout van Crevel, Yang Li, Ronald P. van Rij, Corine GeurtsvanKessel, Marien I. de Jonge, Jorge Domínguez-Andrés, Mihai G. Netea. The BNT162b2 mRNA vaccine against SARS-CoV-2 reprograms both adaptive and innate immune responses. . 2021; ():1.
Chicago/Turabian StyleF. Konstantin Föhse; Büsranur Geckin; Gijs J. Overheul; Josephine van de Maat; Gizem Kilic; Ozlem Bulut; Helga Dijkstra; Heidi Lemmers; S. Andrei Sarlea; Maartje Reijnders; Jacobien Hoogerwerf; Jaap Ten Oever; Elles Simonetti; Frank L. van de Veerdonk; Leo A.B. Joosten; Bart L. Haagmans; Reinout van Crevel; Yang Li; Ronald P. van Rij; Corine GeurtsvanKessel; Marien I. de Jonge; Jorge Domínguez-Andrés; Mihai G. Netea. 2021. "The BNT162b2 mRNA vaccine against SARS-CoV-2 reprograms both adaptive and innate immune responses." , no. : 1.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged as a new human pathogen in late 2019 and it has infected over 100 million people in less than a year. There is a clear need for effective antiviral drugs to complement current preventive measures, including vaccines. In this study, we demonstrate that berberine and obatoclax, two broad-spectrum antiviral compounds, are effective against multiple isolates of SARS-CoV-2. Berberine, a plant-derived alkaloid, inhibited SARS-CoV-2 at low micromolar concentrations and obatoclax, which was originally developed as an anti-apoptotic protein antagonist, was effective at sub-micromolar concentrations. Time-of-addition studies indicated that berberine acts on the late stage of the viral life cycle. In agreement, berberine mildly affected viral RNA synthesis, but it strongly reduced infectious viral titers, leading to an increase in the particle-to-pfu ratio. In contrast, obatoclax acted at the early stage of the infection, which is in line with its activity to neutralize the acidic environment in endosomes. We assessed infection of primary human nasal epithelial cells that were cultured on an air-liquid interface and found that SARS-CoV-2 infection induced and repressed expression of specific sets of cytokines and chemokines. Moreover, both obatoclax and berberine inhibited SARS-CoV-2 replication in these primary target cells. We propose berberine and obatoclax as potential antiviral drugs against SARS-CoV-2 that could be considered for further efficacy testing.
Finny Varghese; Esther van Woudenbergh; Gijs Overheul; Marc Eleveld; Lisa Kurver; Niels van Heerbeek; Arjan van Laarhoven; Pascal Miesen; Gerco Den Hartog; Marien de Jonge; Ronald van Rij. Berberine and Obatoclax Inhibit SARS-Cov-2 Replication in Primary Human Nasal Epithelial Cells In Vitro. Viruses 2021, 13, 282 .
AMA StyleFinny Varghese, Esther van Woudenbergh, Gijs Overheul, Marc Eleveld, Lisa Kurver, Niels van Heerbeek, Arjan van Laarhoven, Pascal Miesen, Gerco Den Hartog, Marien de Jonge, Ronald van Rij. Berberine and Obatoclax Inhibit SARS-Cov-2 Replication in Primary Human Nasal Epithelial Cells In Vitro. Viruses. 2021; 13 (2):282.
Chicago/Turabian StyleFinny Varghese; Esther van Woudenbergh; Gijs Overheul; Marc Eleveld; Lisa Kurver; Niels van Heerbeek; Arjan van Laarhoven; Pascal Miesen; Gerco Den Hartog; Marien de Jonge; Ronald van Rij. 2021. "Berberine and Obatoclax Inhibit SARS-Cov-2 Replication in Primary Human Nasal Epithelial Cells In Vitro." Viruses 13, no. 2: 282.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged as a new human pathogen in late 2019 and has infected an estimated 10% of the global population in less than a year. There is a clear need for effective antiviral drugs to complement current preventive measures including vaccines. In this study, we demonstrate that berberine and obatoclax, two broad-spectrum antiviral compounds, are effective against multiple isolates of SARS-CoV-2. Berberine, a plant-derived alkaloid, inhibited SARS-CoV-2 at low micromolar concentrations and obatoclax, originally developed as an anti-apoptotic protein antagonist, was effective at sub-micromolar concentrations. Time-of-addition studies indicated that berberine acts on the late stage of the viral life cycle. In agreement, berberine mildly affected viral RNA synthesis, but strongly reduced infectious viral titers, leading to an increase in the particle-to-pfu ratio. In contrast, obatoclax acted at the early stage of the infection, in line with its activity to neutralize the acidic environment in endosomes. We assessed infection of primary human nasal epithelial cells cultured on an air-liquid interface and found that SARS-CoV-2 infection induced and repressed expression of a specific set of cytokines and chemokines. Moreover, both obatoclax and berberine inhibited SARS-CoV-2 replication in these primary target cells. We propose berberine and obatoclax as potential antiviral drugs against SARS-CoV-2 that could be considered for further efficacy testing.
Finny S. Varghese; Esther van Woudenbergh; Gijs J. Overheul; Marc J. Eleveld; Lisa Kurver; Niels van Heerbeek; Arjan van Laarhoven; Pascal Miesen; Gerco Den Hartog; Marien I. de Jonge; Ronald P. van Rij. Berberine and obatoclax inhibit SARS-CoV-2 replication in primary human nasal epithelial cells in vitro. 2020, 1 .
AMA StyleFinny S. Varghese, Esther van Woudenbergh, Gijs J. Overheul, Marc J. Eleveld, Lisa Kurver, Niels van Heerbeek, Arjan van Laarhoven, Pascal Miesen, Gerco Den Hartog, Marien I. de Jonge, Ronald P. van Rij. Berberine and obatoclax inhibit SARS-CoV-2 replication in primary human nasal epithelial cells in vitro. . 2020; ():1.
Chicago/Turabian StyleFinny S. Varghese; Esther van Woudenbergh; Gijs J. Overheul; Marc J. Eleveld; Lisa Kurver; Niels van Heerbeek; Arjan van Laarhoven; Pascal Miesen; Gerco Den Hartog; Marien I. de Jonge; Ronald P. van Rij. 2020. "Berberine and obatoclax inhibit SARS-CoV-2 replication in primary human nasal epithelial cells in vitro." , no. : 1.
Herein we provide a living summary of the data generated during the COVID Moonshot project focused on the development of SARS-CoV-2 main protease (Mpro) inhibitors. Our approach uniquely combines crowdsourced medicinal chemistry insights with high throughput crystallography, exascale computational chemistry infrastructure for simulations, and machine learning in triaging designs and predicting synthetic routes. This manuscript describes our methodologies leading to both covalent and non-covalent inhibitors displaying protease IC50 values under 150 nM and viral inhibition under 5 uM in multiple different viral replication assays. Furthermore, we provide over 200 crystal structures of fragment-like and lead-like molecules in complex with the main protease. Over 1000 synthesized and ordered compounds are also reported with the corresponding activity in Mpro enzymatic assays using two different experimental setups. The data referenced in this document will be continually updated to reflect the current experimental progress of the COVID Moonshot project, and serves as a citable reference for ensuing publications. All of the generated data is open to other researchers who may find it of use.
The COVID Moonshot Consortium; Hagit Achdout; Anthony Aimon; Elad Bar-David; Haim Barr; Amir Ben-Shmuel; James Bennett; Melissa L Bobby; Juliane Brun; Sarma Bvnbs; Mark Calmiano; Anna Carbery; Emma Cattermole; John D. Chodera; Austin Clyde; Joseph E. Coffland; Galit Cohen; Jason Cole; Alessandro Contini; Lisa Cox; Milan Cvitkovic; Alex Dias; Alice Douangamath; Shirly Duberstein; Tim Dudgeon; Louise Dunnett; Peter K. Eastman; Noam Erez; Michael Fairhead; Daren Fearon; Oleg Fedorov; Matteo Ferla; Holly Foster; Richard Foster; Ronen Gabizon; Paul Gehrtz; Carina Gileadi; Charline Giroud; William G. Glass; Robert Glen; Itai Glinert; Marian Gorichko; Tyler Gorrie-Stone; Edward J Griffen; Jag Heer; Michelle Hill; Sam Horrell; Matthew F.D. Hurley; Tomer Israely; Andrew Jajack; Eric Jnoff; Tobias John; Anastassia L. Kantsadi; Peter W. Kenny; John L. Kiappes; Lizbe Koekemoer; Boris Kovar; Tobias Krojer; Alpha Albert Lee; Bruce A. Lefker; Haim Levy; Nir London; Petra Lukacik; Hannah Bruce Macdonald; Beth MacLean; Tika R. Malla; Tatiana Matviiuk; Willam McCorkindale; Sharon Melamed; Oleg Michurin; Halina Mikolajek; Aaron Morris; Garrett M. Morris; Melody Jane Morwitzer; Demetri Moustakas; Jose Brandao Neto; Vladas Oleinikovas; Gijs J. Overheul; David Owen; Ruby Pai; Jin Pan; Nir Paran; Benjamin Perry; Maneesh Pingle; Jakir Pinjari; Boaz Politi; Ailsa Powell; Vladimir Psenak; Reut Puni; Victor L. Rangel; Rambabu N. Reddi; St Patrick Reid; Efrat Resnick; Matthew C. Robinson; Ralph P. Robinson; Dominic Rufa; Christopher Schofield; Aarif Shaikh; Jiye Shi; Khriesto Shurrush; Assa Sittner; Rachael Skyner; Adam Smalley; Mihaela D. Smilova; John Spencer; Claire Strain-Damerell; Vishwanath Swamy; Hadas Tamir; Rachael Tennant; Andrew Thompson; Warren Thompson; Susana Tomasio; Anthony Tumber; Ioannis Vakonakis; Ronald P. Van Rij; Finny S. Varghese; Mariana Vaschetto; Einat B. Vitner; Vincent Voelz; Annette Von Delft; Frank Von Delft; Martin Walsh; Walter Ward; Charlie Weatherall; Shay Weiss; Conor Francis Wild; Matthew Wittmann; Nathan Wright; Yfat Yahalom-Ronen; Daniel Zaidmann; Hadeer Zidane; Nicole Zitzmann. COVID Moonshot: Open Science Discovery of SARS-CoV-2 Main Protease Inhibitors by Combining Crowdsourcing, High-Throughput Experiments, Computational Simulations, and Machine Learning. 2020, 1 .
AMA StyleThe COVID Moonshot Consortium, Hagit Achdout, Anthony Aimon, Elad Bar-David, Haim Barr, Amir Ben-Shmuel, James Bennett, Melissa L Bobby, Juliane Brun, Sarma Bvnbs, Mark Calmiano, Anna Carbery, Emma Cattermole, John D. Chodera, Austin Clyde, Joseph E. Coffland, Galit Cohen, Jason Cole, Alessandro Contini, Lisa Cox, Milan Cvitkovic, Alex Dias, Alice Douangamath, Shirly Duberstein, Tim Dudgeon, Louise Dunnett, Peter K. Eastman, Noam Erez, Michael Fairhead, Daren Fearon, Oleg Fedorov, Matteo Ferla, Holly Foster, Richard Foster, Ronen Gabizon, Paul Gehrtz, Carina Gileadi, Charline Giroud, William G. Glass, Robert Glen, Itai Glinert, Marian Gorichko, Tyler Gorrie-Stone, Edward J Griffen, Jag Heer, Michelle Hill, Sam Horrell, Matthew F.D. Hurley, Tomer Israely, Andrew Jajack, Eric Jnoff, Tobias John, Anastassia L. Kantsadi, Peter W. Kenny, John L. Kiappes, Lizbe Koekemoer, Boris Kovar, Tobias Krojer, Alpha Albert Lee, Bruce A. Lefker, Haim Levy, Nir London, Petra Lukacik, Hannah Bruce Macdonald, Beth MacLean, Tika R. Malla, Tatiana Matviiuk, Willam McCorkindale, Sharon Melamed, Oleg Michurin, Halina Mikolajek, Aaron Morris, Garrett M. Morris, Melody Jane Morwitzer, Demetri Moustakas, Jose Brandao Neto, Vladas Oleinikovas, Gijs J. Overheul, David Owen, Ruby Pai, Jin Pan, Nir Paran, Benjamin Perry, Maneesh Pingle, Jakir Pinjari, Boaz Politi, Ailsa Powell, Vladimir Psenak, Reut Puni, Victor L. Rangel, Rambabu N. Reddi, St Patrick Reid, Efrat Resnick, Matthew C. Robinson, Ralph P. Robinson, Dominic Rufa, Christopher Schofield, Aarif Shaikh, Jiye Shi, Khriesto Shurrush, Assa Sittner, Rachael Skyner, Adam Smalley, Mihaela D. Smilova, John Spencer, Claire Strain-Damerell, Vishwanath Swamy, Hadas Tamir, Rachael Tennant, Andrew Thompson, Warren Thompson, Susana Tomasio, Anthony Tumber, Ioannis Vakonakis, Ronald P. Van Rij, Finny S. Varghese, Mariana Vaschetto, Einat B. Vitner, Vincent Voelz, Annette Von Delft, Frank Von Delft, Martin Walsh, Walter Ward, Charlie Weatherall, Shay Weiss, Conor Francis Wild, Matthew Wittmann, Nathan Wright, Yfat Yahalom-Ronen, Daniel Zaidmann, Hadeer Zidane, Nicole Zitzmann. COVID Moonshot: Open Science Discovery of SARS-CoV-2 Main Protease Inhibitors by Combining Crowdsourcing, High-Throughput Experiments, Computational Simulations, and Machine Learning. . 2020; ():1.
Chicago/Turabian StyleThe COVID Moonshot Consortium; Hagit Achdout; Anthony Aimon; Elad Bar-David; Haim Barr; Amir Ben-Shmuel; James Bennett; Melissa L Bobby; Juliane Brun; Sarma Bvnbs; Mark Calmiano; Anna Carbery; Emma Cattermole; John D. Chodera; Austin Clyde; Joseph E. Coffland; Galit Cohen; Jason Cole; Alessandro Contini; Lisa Cox; Milan Cvitkovic; Alex Dias; Alice Douangamath; Shirly Duberstein; Tim Dudgeon; Louise Dunnett; Peter K. Eastman; Noam Erez; Michael Fairhead; Daren Fearon; Oleg Fedorov; Matteo Ferla; Holly Foster; Richard Foster; Ronen Gabizon; Paul Gehrtz; Carina Gileadi; Charline Giroud; William G. Glass; Robert Glen; Itai Glinert; Marian Gorichko; Tyler Gorrie-Stone; Edward J Griffen; Jag Heer; Michelle Hill; Sam Horrell; Matthew F.D. Hurley; Tomer Israely; Andrew Jajack; Eric Jnoff; Tobias John; Anastassia L. Kantsadi; Peter W. Kenny; John L. Kiappes; Lizbe Koekemoer; Boris Kovar; Tobias Krojer; Alpha Albert Lee; Bruce A. Lefker; Haim Levy; Nir London; Petra Lukacik; Hannah Bruce Macdonald; Beth MacLean; Tika R. Malla; Tatiana Matviiuk; Willam McCorkindale; Sharon Melamed; Oleg Michurin; Halina Mikolajek; Aaron Morris; Garrett M. Morris; Melody Jane Morwitzer; Demetri Moustakas; Jose Brandao Neto; Vladas Oleinikovas; Gijs J. Overheul; David Owen; Ruby Pai; Jin Pan; Nir Paran; Benjamin Perry; Maneesh Pingle; Jakir Pinjari; Boaz Politi; Ailsa Powell; Vladimir Psenak; Reut Puni; Victor L. Rangel; Rambabu N. Reddi; St Patrick Reid; Efrat Resnick; Matthew C. Robinson; Ralph P. Robinson; Dominic Rufa; Christopher Schofield; Aarif Shaikh; Jiye Shi; Khriesto Shurrush; Assa Sittner; Rachael Skyner; Adam Smalley; Mihaela D. Smilova; John Spencer; Claire Strain-Damerell; Vishwanath Swamy; Hadas Tamir; Rachael Tennant; Andrew Thompson; Warren Thompson; Susana Tomasio; Anthony Tumber; Ioannis Vakonakis; Ronald P. Van Rij; Finny S. Varghese; Mariana Vaschetto; Einat B. Vitner; Vincent Voelz; Annette Von Delft; Frank Von Delft; Martin Walsh; Walter Ward; Charlie Weatherall; Shay Weiss; Conor Francis Wild; Matthew Wittmann; Nathan Wright; Yfat Yahalom-Ronen; Daniel Zaidmann; Hadeer Zidane; Nicole Zitzmann. 2020. "COVID Moonshot: Open Science Discovery of SARS-CoV-2 Main Protease Inhibitors by Combining Crowdsourcing, High-Throughput Experiments, Computational Simulations, and Machine Learning." , no. : 1.
In the germline of animals, PIWI interacting (pi)RNAs protect the genome against the detrimental effects of transposon mobilization. In Drosophila, piRNA-mediated cleavage of transposon RNA triggers the production of responder piRNAs via ping-pong amplification. Responder piRNA 3’ end formation is coupled to the production of downstream trailer piRNAs mediated by the nuclease Zucchini, expanding the repertoire of transposon piRNA sequences. In Aedes aegypti mosquitoes, piRNAs are generated from viral RNA, yet, it is unknown how viral piRNA 3’ ends are formed and whether viral RNA cleavage gives rise to trailer piRNA production. Here we report that in Ae. aegypti, virus- and transposon-derived piRNAs have sharp 3’ ends, and are biased for downstream uridine residues, features reminiscent of Zucchini cleavage of precursor piRNAs in Drosophila. We designed a reporter system to study viral piRNA 3’ end formation and found that targeting viral RNA by abundant endogenous piRNAs triggers the production of responder and trailer piRNAs. Using this reporter, we identified the Ae. aegypti orthologs of Zucchini and Nibbler, two nucleases involved in piRNA 3’ end formation. Our results furthermore suggest that autonomous piRNA production from viral RNA can be triggered and expanded by an initial cleavage event guided by genome-encoded piRNAs.
Joep Joosten; Gijs J. Overheul; Ronald P. Van Rij; Pascal Miesen. Endogenous piRNA-guided slicing triggers responder and trailer piRNA production from viral RNA in Aedes aegypti mosquitoes. 2020, 1 .
AMA StyleJoep Joosten, Gijs J. Overheul, Ronald P. Van Rij, Pascal Miesen. Endogenous piRNA-guided slicing triggers responder and trailer piRNA production from viral RNA in Aedes aegypti mosquitoes. . 2020; ():1.
Chicago/Turabian StyleJoep Joosten; Gijs J. Overheul; Ronald P. Van Rij; Pascal Miesen. 2020. "Endogenous piRNA-guided slicing triggers responder and trailer piRNA production from viral RNA in Aedes aegypti mosquitoes." , no. : 1.
The genus Alphavirus harbours mostly insect-transmitted viruses that cause severe disease in humans, livestock and wildlife. Thus far, only three alphaviruses with a host range restricted to insects have been found in mosquitoes from the Old World, namely Eilat virus (EILV), Taï Forest alphavirus (TALV) and Mwinilunga alphavirus (MWAV). In this study, we found a novel alphavirus in one Culex declarator mosquito sampled in Panama. The virus was isolated in C6/36 mosquito cells, and full genome sequencing revealed an 11 468 nt long genome with maximum pairwise nucleotide identity of 62.7% to Sindbis virus. Phylogenetic analyses placed the virus as a solitary deep rooting lineage in a basal relationship to the Western equine encephalitis antigenic complex and to the clade comprising EILV, TALV and MWAV, indicating the detection of a novel alphavirus, tentatively named Agua Salud alphavirus (ASALV). No growth of ASALV was detected in vertebrate cell lines, including cell lines derived from ectothermic animals, and replication of ASALV was strongly impaired above 31 °C, suggesting that ASALV represents the first insect-restricted alphavirus of the New World.
Kyra Hermanns; Marco Marklewitz; Florian Zirkel; Gijs J. Overheul; Rachel A. Page; Jose R. Loaiza; Christian Drosten; Ronald P. Van Rij; Sandra Junglen. Agua Salud alphavirus defines a novel lineage of insect-specific alphaviruses discovered in the New World. Journal of General Virology 2020, 101, 96 -104.
AMA StyleKyra Hermanns, Marco Marklewitz, Florian Zirkel, Gijs J. Overheul, Rachel A. Page, Jose R. Loaiza, Christian Drosten, Ronald P. Van Rij, Sandra Junglen. Agua Salud alphavirus defines a novel lineage of insect-specific alphaviruses discovered in the New World. Journal of General Virology. 2020; 101 (1):96-104.
Chicago/Turabian StyleKyra Hermanns; Marco Marklewitz; Florian Zirkel; Gijs J. Overheul; Rachel A. Page; Jose R. Loaiza; Christian Drosten; Ronald P. Van Rij; Sandra Junglen. 2020. "Agua Salud alphavirus defines a novel lineage of insect-specific alphaviruses discovered in the New World." Journal of General Virology 101, no. 1: 96-104.
Coevolution of viruses and their hosts may lead to viral strategies to avoid, evade, or suppress antiviral immunity. An example is antiviral RNA interference (RNAi) in insects: the host RNAi machinery processes viral double-stranded RNA into small interfering RNAs (siRNAs) to suppress viral replication, whereas insect viruses encode suppressors of RNAi, many of which inhibit viral small interfering RNA (vsiRNA) production. Yet, many studies have analyzed viral RNAi suppressors in heterologous systems, due to the lack of experimental systems to manipulate the viral genome of interest, raising questions about in vivo functions of RNAi suppressors. To address this caveat, we generated an RNAi suppressor-defective mutant of invertebrate iridescent virus 6 (IIV6), a large DNA virus in which we previously identified the 340R protein as a suppressor of RNAi. Loss of 340R did not affect vsiRNA production, indicating that 340R binds siRNA duplexes to prevent RNA-induced silencing complex assembly. Indeed, vsiRNAs were not efficiently loaded into Argonaute 2 during wild-type IIV6 infection. Moreover, IIV6 induced a limited set of mature microRNAs in a 340R-dependent manner, most notably miR-305–3p, which we attribute to stabilization of the miR-305–5p:3p duplex by 340R. The IIV6 340R deletion mutant did not have a replication defect in cells, but was strongly attenuated in adult Drosophila. This in vivo replication defect was completely rescued in RNAi mutant flies, indicating that 340R is a bona fide RNAi suppressor, the absence of which uncovers a potent antiviral immune response that suppresses virus accumulation ∼100-fold. Together, our work indicates that viral RNAi suppressors may completely mask antiviral immunity.
Alfred W. Bronkhorst; Rob Vogels; Gijs J. Overheul; Bas Pennings; Valérie Gausson-Dorey; Pascal Miesen; Ronald P. van Rij. A DNA virus-encoded immune antagonist fully masks the potent antiviral activity of RNAi in Drosophila. Proceedings of the National Academy of Sciences 2019, 116, 24296 -24302.
AMA StyleAlfred W. Bronkhorst, Rob Vogels, Gijs J. Overheul, Bas Pennings, Valérie Gausson-Dorey, Pascal Miesen, Ronald P. van Rij. A DNA virus-encoded immune antagonist fully masks the potent antiviral activity of RNAi in Drosophila. Proceedings of the National Academy of Sciences. 2019; 116 (48):24296-24302.
Chicago/Turabian StyleAlfred W. Bronkhorst; Rob Vogels; Gijs J. Overheul; Bas Pennings; Valérie Gausson-Dorey; Pascal Miesen; Ronald P. van Rij. 2019. "A DNA virus-encoded immune antagonist fully masks the potent antiviral activity of RNAi in Drosophila." Proceedings of the National Academy of Sciences 116, no. 48: 24296-24302.
RNA interference (RNAi) has strong antiviral activity in a range of animal phyla, but the extent to which RNAi controls virus infection in chordates, and specifically mammals remains incompletely understood. Here we analyze the antiviral activity of RNAi against a number of positive-sense RNA viruses using Argonaute-2 deficient human cells. In line with absence of virus-derived siRNAs, Sindbis virus, yellow fever virus, and encephalomyocarditis virus replicated with similar kinetics in wildtype cells and Argonaute-2 deficient cells. Coxsackievirus B3 (CVB3) carrying mutations in the viral 3A protein, previously proposed to be a virus-encoded suppressor of RNAi in another picornavirus, human enterovirus 71, had a strong replication defect in wildtype cells. However, this defect was not rescued in Argonaute-2 deficient cells, arguing against a role of CVB3 3A as an RNAi suppressor. In agreement, neither infection with wildtype nor 3A mutant CVB3 resulted in small RNA production with the hallmarks of canonical vsiRNAs. Together, our results argue against strong antiviral activity of RNAi under these experimental conditions, but do not exclude that antiviral RNAi may be functional under other cellular, experimental, or physiological conditions in mammals.
Susan Schuster; Gijs Overheul; Lisa Bauer; Frank J. M. Van Kuppeveld; Ronald P. Van Rij. No evidence for viral small RNA production and antiviral function of Argonaute 2 in human cells. Scientific Reports 2019, 9, 1 -11.
AMA StyleSusan Schuster, Gijs Overheul, Lisa Bauer, Frank J. M. Van Kuppeveld, Ronald P. Van Rij. No evidence for viral small RNA production and antiviral function of Argonaute 2 in human cells. Scientific Reports. 2019; 9 (1):1-11.
Chicago/Turabian StyleSusan Schuster; Gijs Overheul; Lisa Bauer; Frank J. M. Van Kuppeveld; Ronald P. Van Rij. 2019. "No evidence for viral small RNA production and antiviral function of Argonaute 2 in human cells." Scientific Reports 9, no. 1: 1-11.
Small RNA mediated responses are essential for antiviral defence in mosquitoes, however, they appear to differ per virus-vector combination. To further investigate the diversity of small RNA responses against viruses in mosquitoes, we applied a small RNA deep sequencing approach on five mosquito cell lines: Culex tarsalis CT cells, Aedes albopictus U4.4 and C6/36 cells, Ae. aegypti Aag2 cells (cleared from cell fusing agent virus and Culex Y virus (CYV) by repetitive dsRNA transfections) and Ae. pseudoscutellaris AP-61 cells. De novo assembly of small RNAs revealed the presence of Phasi Charoen-like virus (PCLV), Calbertado virus, Flock House virus and a novel narnavirus in CT cells, CYV in U4.4 cells, and PCLV in Aag2 cells, whereas no insect-specific viruses (ISVs) were detected in C6/36 and AP-61 cells. Next, we investigated the small RNA responses to the identified ISVs and to acute infection with the arthropod-borne West Nile virus (WNV). We demonstrate that AP-61 and C6/36 cells do not produce siRNAs to WNV infection, suggesting that AP-61, like C6/36, are Dicer-2 deficient. CT cells produced a strong siRNA response to the persistent ISVs and acute WNV infection. Interestingly, CT cells also produced viral PIWI-interacting (pi)RNAs to PCLV, but not to WNV or any of the other ISVs. In contrast, in U4.4 and Aag2 cells, WNV siRNAs, and pi-like RNAs without typical ping-pong piRNA signature were observed, while this signature was present in PCLV piRNAs in Aag2 cells. Together, our results demonstrate that mosquito small RNA responses are strongly dependent on both the mosquito cell type and/or the mosquito species and family of the infecting virus.
Giel P. Göertz; Pascal Miesen; Gijs J. Overheul; Ronald P. Van Rij; Monique M. Van Oers; Gorben P. Pijlman. Mosquito Small RNA Responses to West Nile and Insect-Specific Virus Infections in Aedes and Culex Mosquito Cells. Viruses 2019, 11, 271 .
AMA StyleGiel P. Göertz, Pascal Miesen, Gijs J. Overheul, Ronald P. Van Rij, Monique M. Van Oers, Gorben P. Pijlman. Mosquito Small RNA Responses to West Nile and Insect-Specific Virus Infections in Aedes and Culex Mosquito Cells. Viruses. 2019; 11 (3):271.
Chicago/Turabian StyleGiel P. Göertz; Pascal Miesen; Gijs J. Overheul; Ronald P. Van Rij; Monique M. Van Oers; Gorben P. Pijlman. 2019. "Mosquito Small RNA Responses to West Nile and Insect-Specific Virus Infections in Aedes and Culex Mosquito Cells." Viruses 11, no. 3: 271.
Thrombocytopenia and platelet dysfunction are commonly observed in patients with dengue virus (DENV) infection and may contribute to complications such as bleeding and plasma leakage. The etiology of dengue-associated thrombocytopenia is multifactorial and includes increased platelet clearance. The binding of the coagulation protein von Willebrand factor (VWF) to the platelet membrane and removal of sialic acid (desialylation) are two well-known mechanisms of platelet clearance, but whether these conditions also contribute to thrombocytopenia in dengue infection is unknown. In two observational cohort studies in Bandung and Jepara, Indonesia, we show that adult patients with dengue not only had higher plasma concentrations of plasma VWF antigen and active VWF, but that circulating platelets had also bound more VWF to their membrane. The amount of platelet-VWF binding correlated well with platelet count. Furthermore, sialic acid levels in dengue patients were significantly reduced as assessed by the binding of Sambucus nigra lectin (SNA) and Maackia amurensis lectin II (MAL-II) to platelets. Sialic acid on the platelet membrane is neuraminidase-labile, but dengue virus has no known neuraminidase activity. Indeed, no detectable activity of neuraminidase was present in plasma of dengue patients and no desialylation was found of plasma transferrin. Platelet sialylation was also not altered by in vitro exposure of platelets to DENV nonstructural protein 1 or cultured DENV. In contrast, induction of binding of VWF to glycoprotein 1b on platelets using the VWF-activating protein ristocetin resulted in the removal of platelet sialic acid by translocation of platelet neuraminidase to the platelet surface. The neuraminidase inhibitor oseltamivir reduced VWF-induced platelet desialylation. Our data demonstrate that excessive binding of VWF to platelets in dengue results in neuraminidase-mediated platelet desialylation and platelet clearance. Oseltamivir might be a novel treatment option for severe thrombocytopenia in dengue infection.
Silvita Fitri Riswari; Rahajeng N. Tunjungputri; Vesla Kullaya; Fadel Muhammad Garishah; Gloria S. R. Utari; Nur Farhanah; Gijs Overheul; Bachti Alisjahbana; M. Hussein Gasem; Rolf Urbanus; Philip. G. De Groot; Dirk J. Lefeber; Ronald P. Van Rij; Andre Van Der Ven; Quirijn De Mast. Desialylation of platelets induced by Von Willebrand Factor is a novel mechanism of platelet clearance in dengue. PLOS Pathogens 2019, 15, e1007500 .
AMA StyleSilvita Fitri Riswari, Rahajeng N. Tunjungputri, Vesla Kullaya, Fadel Muhammad Garishah, Gloria S. R. Utari, Nur Farhanah, Gijs Overheul, Bachti Alisjahbana, M. Hussein Gasem, Rolf Urbanus, Philip. G. De Groot, Dirk J. Lefeber, Ronald P. Van Rij, Andre Van Der Ven, Quirijn De Mast. Desialylation of platelets induced by Von Willebrand Factor is a novel mechanism of platelet clearance in dengue. PLOS Pathogens. 2019; 15 (3):e1007500.
Chicago/Turabian StyleSilvita Fitri Riswari; Rahajeng N. Tunjungputri; Vesla Kullaya; Fadel Muhammad Garishah; Gloria S. R. Utari; Nur Farhanah; Gijs Overheul; Bachti Alisjahbana; M. Hussein Gasem; Rolf Urbanus; Philip. G. De Groot; Dirk J. Lefeber; Ronald P. Van Rij; Andre Van Der Ven; Quirijn De Mast. 2019. "Desialylation of platelets induced by Von Willebrand Factor is a novel mechanism of platelet clearance in dengue." PLOS Pathogens 15, no. 3: e1007500.
The fruit fly Drosophila melanogaster is a valuable model organism for the discovery and characterization of innate immune pathways, but host responses to virus infection remain incompletely understood. Here, we describe a novel player in host defense, Sgroppino (Sgp). Genetic depletion of Sgroppino causes hypersensitivity of adult flies to infections with the RNA viruses Drosophila C virus, cricket paralysis virus, and Flock House virus. Canonical antiviral immune pathways are functional in Sgroppino mutants, suggesting that Sgroppino exerts its activity via an as yet uncharacterized process. We demonstrate that Sgroppino localizes to peroxisomes, organelles involved in lipid metabolism. In accordance, Sgroppino-deficient flies show a defect in lipid metabolism, reflected by higher triglyceride levels, higher body mass, and thicker abdominal fat tissue. In addition, knock-down of Pex3, an essential peroxisome biogenesis factor, increases sensitivity to virus infection. Together, our results establish a genetic link between the peroxisomal protein Sgroppino, fat metabolism, and resistance to virus infection.
Sarah H. Merkling; Human Riahi; Gijs Overheul; Annette Schenck; Ronald P. Van Rij. Peroxisome-associated Sgroppino links fat metabolism with survival after RNA virus infection in Drosophila. Scientific Reports 2019, 9, 1 -12.
AMA StyleSarah H. Merkling, Human Riahi, Gijs Overheul, Annette Schenck, Ronald P. Van Rij. Peroxisome-associated Sgroppino links fat metabolism with survival after RNA virus infection in Drosophila. Scientific Reports. 2019; 9 (1):1-12.
Chicago/Turabian StyleSarah H. Merkling; Human Riahi; Gijs Overheul; Annette Schenck; Ronald P. Van Rij. 2019. "Peroxisome-associated Sgroppino links fat metabolism with survival after RNA virus infection in Drosophila." Scientific Reports 9, no. 1: 1-12.
Coevolution of multicellular organisms and their natural viruses may lead to an intricate relationship in which host survival requires effective immunity and virus survival depends on evasion of such responses. Insect antiviral immunity and reciprocal virus immunosuppression tactics have been well studied in Drosophila melanogaster , primarily during RNA, but not DNA, virus infection. Therefore, we describe interactions between a recently isolated Drosophila DNA virus (Kallithea virus [KV]) and immune processes known to control RNA viruses, such as RNA interference (RNAi) and Imd pathways. We found that KV suppresses the Toll pathway and identified gp83 as a KV-encoded protein that underlies this suppression. This immunosuppressive ability is conserved in another nudivirus, suggesting that the Toll pathway has conserved antiviral activity against DNA nudiviruses, which have evolved suppressors in response. Together, these results indicate that DNA viruses induce and suppress NF-κB responses, and they advance the application of KV as a model to study insect immunity.
William H. Palmer; Joep Joosten; Gijs J. Overheul; Pascal W. Jansen; Michiel Vermeulen; Darren J. Obbard; Ronald P. Van Rij. Induction and Suppression of NF-κB Signalling by a DNA Virus of Drosophila. Journal of Virology 2019, 93, e01443-18 .
AMA StyleWilliam H. Palmer, Joep Joosten, Gijs J. Overheul, Pascal W. Jansen, Michiel Vermeulen, Darren J. Obbard, Ronald P. Van Rij. Induction and Suppression of NF-κB Signalling by a DNA Virus of Drosophila. Journal of Virology. 2019; 93 (3):e01443-18.
Chicago/Turabian StyleWilliam H. Palmer; Joep Joosten; Gijs J. Overheul; Pascal W. Jansen; Michiel Vermeulen; Darren J. Obbard; Ronald P. Van Rij. 2019. "Induction and Suppression of NF-κB Signalling by a DNA Virus of Drosophila." Journal of Virology 93, no. 3: e01443-18.
Dengue virus (DENV) is associated with an estimated 390 million infections per year, occurring across approximately 100 countries in tropical and sub-tropical regions. To date, there are no antiviral drugs or specific therapies to treat DENV infection. Posaconazole and itraconazole are potent antifungal drugs that inhibit ergosterol biosynthesis in fungal cells, but also target a number of human proteins. Here, we show that itraconazole and posaconazole have antiviral activity against DENV. Posaconazole inhibited replication of multiple serotypes of DENV and the related flavivirus Zika virus, and reduced viral RNA replication, but not translation of the viral genome. We used a combination of knockdown and drug sensitization assays to define the molecular target of posaconazole that mediates its antiviral activity. We found that knockdown of oxysterol-binding protein (OSBP) inhibited DENV replication. Moreover, knockdown of OSBP, but not other known targets of posaconazole, enhanced the inhibitory effect of posaconazole. Our findings imply OSBP as a potential target for the development of antiviral compounds against DENV.
Febrina Meutiawati; Bodine Bezemer; Jeroen R.P.M. Strating; Gijs Overheul; Eva Žusinaite; Frank J.M. van Kuppeveld; Koen W.R. van Cleef; Ronald P. van Rij. Posaconazole inhibits dengue virus replication by targeting oxysterol-binding protein. Antiviral Research 2018, 157, 68 -79.
AMA StyleFebrina Meutiawati, Bodine Bezemer, Jeroen R.P.M. Strating, Gijs Overheul, Eva Žusinaite, Frank J.M. van Kuppeveld, Koen W.R. van Cleef, Ronald P. van Rij. Posaconazole inhibits dengue virus replication by targeting oxysterol-binding protein. Antiviral Research. 2018; 157 ():68-79.
Chicago/Turabian StyleFebrina Meutiawati; Bodine Bezemer; Jeroen R.P.M. Strating; Gijs Overheul; Eva Žusinaite; Frank J.M. van Kuppeveld; Koen W.R. van Cleef; Ronald P. van Rij. 2018. "Posaconazole inhibits dengue virus replication by targeting oxysterol-binding protein." Antiviral Research 157, no. : 68-79.
Interactions between the insect immune system and RNA viruses have been best studied in Drosophila, where RNA interference, NF-kB and JAK-STAT pathways underlie antiviral immunity. In response to these immune mechanisms, insect viruses have convergently evolved suppressors of RNA interference that act by diverse mechanisms to permit viral replication. However, interactions between the insect immune system and DNA viruses have received less attention, primarily because few Drosophila-infecting DNA virus isolates are available. Here, we use a recently-isolated DNA virus of Drosophila melanogaster, Kallithea virus, to probe known antiviral immune responses and virus evasion tactics in the context of DNA virus infection. We find that fly mutants for RNA interference and Immune deficiency (Imd), but not Toll, pathways are more susceptible to Kallithea virus infection. We identify the Kallithea virus-encoded protein gp83 as a potent inhibitor of Toll signalling, strongly suggesting that Toll mediates antiviral responses during Kallithea virus infection, but that it is suppressed by the virus. Further, we find that Kallithea gp83 inhibits Toll signalling either through NF-kB transcription factor regulation, or transcriptionally. Together, these results provide a broad description of known antiviral pathways in the context of DNA virus infection and identify the first Toll pathway inhibitor in a Drosophila virus, extending the known diversity of insect virus-encoded immune inhibitors.
William H. Palmer; Joep Joosten; Gijs J. Overheul; Pascal W. Jansen; Michiel Vermeulen; Darren J. Obbard; Ronald P. Van Rij. Induction and suppression of NF-kB signalling by a DNA virus of Drosophila. 2018, 358176 .
AMA StyleWilliam H. Palmer, Joep Joosten, Gijs J. Overheul, Pascal W. Jansen, Michiel Vermeulen, Darren J. Obbard, Ronald P. Van Rij. Induction and suppression of NF-kB signalling by a DNA virus of Drosophila. . 2018; ():358176.
Chicago/Turabian StyleWilliam H. Palmer; Joep Joosten; Gijs J. Overheul; Pascal W. Jansen; Michiel Vermeulen; Darren J. Obbard; Ronald P. Van Rij. 2018. "Induction and suppression of NF-kB signalling by a DNA virus of Drosophila." , no. : 358176.
Summary Enteroviruses reorganize cellular endomembranes into replication organelles (ROs) for genome replication. Although enterovirus replication depends on phosphatidylinositol 4-kinase type IIIβ (PI4KB), its role, and that of its product, phosphatidylinositol 4-phosphate (PI4P), is only partially understood. Exploiting a mutant coxsackievirus resistant to PI4KB inhibition, we show that PI4KB activity has distinct functions both in proteolytic processing of the viral polyprotein and in RO biogenesis. The escape mutation rectifies a proteolytic processing defect imposed by PI4KB inhibition, pointing to a possible escape mechanism. Remarkably, under PI4KB inhibition, the mutant virus could replicate its genome in the absence of ROs, using instead the Golgi apparatus. This impaired RO biogenesis provided an opportunity to investigate the proposed role of ROs in shielding enteroviral RNA from cellular sensors. Neither accelerated sensing of viral RNA nor enhanced innate immune responses was observed. Together, our findings challenge the notion that ROs are indispensable for enterovirus genome replication and immune evasion.
Charlotte E. Melia; Hilde M. Van Der Schaar; Heyrhyoung Lyoo; Ronald Limpens; Qian Feng; Maryam Wahedi; Gijs Overheul; Ronald P. Van Rij; Eric Snijder; Abraham J. Koster; Montserrat Bárcena; Frank J.M. Van Kuppeveld. Escaping Host Factor PI4KB Inhibition: Enterovirus Genomic RNA Replication in the Absence of Replication Organelles. Cell Reports 2017, 21, 587 -599.
AMA StyleCharlotte E. Melia, Hilde M. Van Der Schaar, Heyrhyoung Lyoo, Ronald Limpens, Qian Feng, Maryam Wahedi, Gijs Overheul, Ronald P. Van Rij, Eric Snijder, Abraham J. Koster, Montserrat Bárcena, Frank J.M. Van Kuppeveld. Escaping Host Factor PI4KB Inhibition: Enterovirus Genomic RNA Replication in the Absence of Replication Organelles. Cell Reports. 2017; 21 (3):587-599.
Chicago/Turabian StyleCharlotte E. Melia; Hilde M. Van Der Schaar; Heyrhyoung Lyoo; Ronald Limpens; Qian Feng; Maryam Wahedi; Gijs Overheul; Ronald P. Van Rij; Eric Snijder; Abraham J. Koster; Montserrat Bárcena; Frank J.M. Van Kuppeveld. 2017. "Escaping Host Factor PI4KB Inhibition: Enterovirus Genomic RNA Replication in the Absence of Replication Organelles." Cell Reports 21, no. 3: 587-599.
The contribution of the RNA interference (RNAi) pathway in antiviral immunity in vertebrates has been widely debated. It has been proposed that RNAi possesses antiviral activity in mammalian systems but that its antiviral effect is masked by the potent antiviral interferon response in differentiated mammalian cells. In this study, we show that inactivation of the interferon response is not sufficient to uncover antiviral activity of RNAi in human epithelial cells infected with three wild-type positive-sense RNA viruses.
Susan Schuster; Lotte E. Tholen; Gijs J. Overheul; Frank J. M. van Kuppeveld; Ronald P. van Rij. Deletion of Cytoplasmic Double-Stranded RNA Sensors Does Not Uncover Viral Small Interfering RNA Production in Human Cells. mSphere 2017, 2, e00333-17 .
AMA StyleSusan Schuster, Lotte E. Tholen, Gijs J. Overheul, Frank J. M. van Kuppeveld, Ronald P. van Rij. Deletion of Cytoplasmic Double-Stranded RNA Sensors Does Not Uncover Viral Small Interfering RNA Production in Human Cells. mSphere. 2017; 2 (4):e00333-17.
Chicago/Turabian StyleSusan Schuster; Lotte E. Tholen; Gijs J. Overheul; Frank J. M. van Kuppeveld; Ronald P. van Rij. 2017. "Deletion of Cytoplasmic Double-Stranded RNA Sensors Does Not Uncover Viral Small Interfering RNA Production in Human Cells." mSphere 2, no. 4: e00333-17.
Despite the enormous disease burden associated with dengue virus infections, a licensed antiviral drug is lacking. Here, we show that the paracetamol (acetaminophen) metabolite AM404 inhibits dengue virus replication. Moreover, we find that mutations in NS4B that were previously found to confer resistance to the antiviral compounds NITD-618 and SDM25N also render dengue virus insensitive to AM404. Our work provides further support for NS4B as a direct or indirect target for antiviral drug development.
Koen W. R. van Cleef; Gijs J. Overheul; Michael C. Thomassen; Jenni M. Marjakangas; Ronald P. van Rij. Escape Mutations in NS4B Render Dengue Virus Insensitive to the Antiviral Activity of the Paracetamol Metabolite AM404. Antimicrobial Agents and Chemotherapy 2016, 60, 2554 -2557.
AMA StyleKoen W. R. van Cleef, Gijs J. Overheul, Michael C. Thomassen, Jenni M. Marjakangas, Ronald P. van Rij. Escape Mutations in NS4B Render Dengue Virus Insensitive to the Antiviral Activity of the Paracetamol Metabolite AM404. Antimicrobial Agents and Chemotherapy. 2016; 60 (4):2554-2557.
Chicago/Turabian StyleKoen W. R. van Cleef; Gijs J. Overheul; Michael C. Thomassen; Jenni M. Marjakangas; Ronald P. van Rij. 2016. "Escape Mutations in NS4B Render Dengue Virus Insensitive to the Antiviral Activity of the Paracetamol Metabolite AM404." Antimicrobial Agents and Chemotherapy 60, no. 4: 2554-2557.
Innate immunity is the first line of defence against pathogens and is essential for survival of the infected host. The fruit fly Drosophila melanogaster is an emerging model to study viral pathogenesis, yet antiviral defence responses remain poorly understood. Here, we describe the heat shock response, a cellular mechanism that prevents proteotoxicity, as a component of the antiviral immune response in Drosophila. Transcriptome analyses of Drosophila S2 cells and adult flies revealed strong induction of the heat shock response upon RNA virus infection. Dynamic induction patterns of heat shock pathway components were characterized in vitro and in vivo following infection with different classes of viruses. The heat shock transcription factor (Hsf), as well as active viral replication, were necessary for the induction of the response. Hsf-deficient adult flies were hypersensitive to virus infection, indicating a role of the heat shock response in antiviral defence. In accordance, transgenic activation of the heat shock response prolonged survival time after infection and enabled long-term control of virus replication to undetectable levels. Together, our results establish the heat shock response as an important constituent of innate antiviral immunity in Drosophila.
Sarah H. Merkling; Gijs Overheul; Joël T. Van Mierlo; Daan Arends; Christian Gilissen; Ronald P. Van Rij. The heat shock response restricts virus infection in Drosophila. Scientific Reports 2015, 5, 12758 .
AMA StyleSarah H. Merkling, Gijs Overheul, Joël T. Van Mierlo, Daan Arends, Christian Gilissen, Ronald P. Van Rij. The heat shock response restricts virus infection in Drosophila. Scientific Reports. 2015; 5 (1):12758.
Chicago/Turabian StyleSarah H. Merkling; Gijs Overheul; Joël T. Van Mierlo; Daan Arends; Christian Gilissen; Ronald P. Van Rij. 2015. "The heat shock response restricts virus infection in Drosophila." Scientific Reports 5, no. 1: 12758.
Little is known about the tolerance mechanisms that reduce the negative effects of microbial infection on host fitness. Here, we demonstrate that the histone H3 lysine 9 methyltransferase G9a regulates tolerance to virus infection by shaping the response of the evolutionary conserved Jak-Stat pathway in Drosophila. G9a-deficient mutants are more sensitive to RNA virus infection and succumb faster to infection than wild-type controls, which was associated with strongly increased Jak-Stat dependent responses, but not with major differences in viral load. Genetic experiments indicate that hyperactivated Jak-Stat responses are associated with early lethality in virus-infected flies. Our results identify an essential epigenetic mechanism underlying tolerance to virus infection. Multicellular organisms deploy various strategies to fight microbial infections. Invading pathogens may be eradicated directly by antimicrobial effectors of the immune system. Another strategy consists of increasing the tolerance of the host to infection, for example, by limiting the adverse effects of the immune response. The molecular mechanisms underlying this novel concept remain largely uncharacterized. Here, we demonstrate that the epigenetic regulator G9a mediates tolerance to virus infection in Drosophila. We found that G9a-deficient flies succumb faster than control flies to infection with RNA viruses, but that the viral burden did not significantly differ. Unexpectedly, mutant flies express higher levels of genes that are regulated by the Jak-Stat signaling pathway, which in other studies was found to be important for antiviral defense. Exploiting the genetic toolbox in Drosophila, we demonstrate that Jak-Stat hyperactivation induces early mortality after virus infection. Precise control of immune pathways is essential to ensure efficient immunity, while preventing damage due to excessive immune responses. Our results indicate that G9a, an epigenetic modifier, dampens Jak-Stat responses to prevent immunopathology. Therefore, we propose epigenetic regulation of immunity as a new paradigm for disease tolerance.
Sarah H. Merkling; Alfred W. Bronkhorst; Jamie Kramer; Gijs Overheul; Annette Schenck; Ronald P. Van Rij. The Epigenetic Regulator G9a Mediates Tolerance to RNA Virus Infection in Drosophila. PLOS Pathogens 2015, 11, e1004692 .
AMA StyleSarah H. Merkling, Alfred W. Bronkhorst, Jamie Kramer, Gijs Overheul, Annette Schenck, Ronald P. Van Rij. The Epigenetic Regulator G9a Mediates Tolerance to RNA Virus Infection in Drosophila. PLOS Pathogens. 2015; 11 (4):e1004692.
Chicago/Turabian StyleSarah H. Merkling; Alfred W. Bronkhorst; Jamie Kramer; Gijs Overheul; Annette Schenck; Ronald P. Van Rij. 2015. "The Epigenetic Regulator G9a Mediates Tolerance to RNA Virus Infection in Drosophila." PLOS Pathogens 11, no. 4: e1004692.
The ongoing conflict between viruses and their hosts can drive the co-evolution between host immune genes and viral suppressors of immunity. It has been suggested that an evolutionary ‘arms race’ may occur between rapidly evolving components of the antiviral RNAi pathway of Drosophila and viral genes that antagonize it. We have recently shown that viral protein 1 (VP1) of Drosophila melanogaster Nora virus (DmelNV) suppresses Argonaute-2 (AGO2)-mediated target RNA cleavage (slicer activity) to antagonize antiviral RNAi. Here we show that viral AGO2 antagonists of divergent Nora-like viruses can have host specific activities. We have identified novel Nora-like viruses in wild-caught populations of D. immigrans (DimmNV) and D. subobscura (DsubNV) that are 36% and 26% divergent from DmelNV at the amino acid level. We show that DimmNV and DsubNV VP1 are unable to suppress RNAi in D. melanogaster S2 cells, whereas DmelNV VP1 potently suppresses RNAi in this host species. Moreover, we show that the RNAi suppressor activity of DimmNV VP1 is restricted to its natural host species, D. immigrans. Specifically, we find that DimmNV VP1 interacts with D. immigrans AGO2, but not with D. melanogaster AGO2, and that it suppresses slicer activity in embryo lysates from D. immigrans, but not in lysates from D. melanogaster. This species-specific interaction is reflected in the ability of DimmNV VP1 to enhance RNA production by a recombinant Sindbis virus in a host-specific manner. Our results emphasize the importance of analyzing viral RNAi suppressor activity in the relevant host species. We suggest that rapid co-evolution between RNA viruses and their hosts may result in host species-specific activities of RNAi suppressor proteins, and therefore that viral RNAi suppressors could be host-specificity factors. Viruses and their hosts can engage in an evolutionary arms race. Viruses may select for hosts with more effective immune responses, whereas the immune response of the host may select for viruses that evade the immune system. These viral counter-defenses may in turn drive adaptations in host immune genes. A potential outcome of this perpetual cycle is that the interaction between virus and host becomes more specific. In insects, the host antiviral RNAi machinery exerts strong evolutionary pressure that has led to the evolution of viral proteins that can antagonize the RNAi response. We have identified novel viruses that infect different fruit fly species and we show that the RNAi suppressor proteins of these viruses can be specific to their host. Furthermore, we show that these proteins can enhance virus replication in a host-specific manner. These results are in line with the hypothesis that virus-host co-evolution shapes the genomes of both virus and host. Moreover, our results suggest that RNAi suppressor proteins have the potential to determine host specificity of viruses.
Joël T. Van Mierlo; Gijs Overheul; Benjamin Obadia; Koen W. R. Van Cleef; Claire L. Webster; Maria-Carla Saleh; Darren J. Obbard; Ronald P. Van Rij. Novel Drosophila Viruses Encode Host-Specific Suppressors of RNAi. PLOS Pathogens 2014, 10, e1004256 .
AMA StyleJoël T. Van Mierlo, Gijs Overheul, Benjamin Obadia, Koen W. R. Van Cleef, Claire L. Webster, Maria-Carla Saleh, Darren J. Obbard, Ronald P. Van Rij. Novel Drosophila Viruses Encode Host-Specific Suppressors of RNAi. PLOS Pathogens. 2014; 10 (7):e1004256.
Chicago/Turabian StyleJoël T. Van Mierlo; Gijs Overheul; Benjamin Obadia; Koen W. R. Van Cleef; Claire L. Webster; Maria-Carla Saleh; Darren J. Obbard; Ronald P. Van Rij. 2014. "Novel Drosophila Viruses Encode Host-Specific Suppressors of RNAi." PLOS Pathogens 10, no. 7: e1004256.