scholarly journals The Enterovirus Protease Inhibitor Rupintrivir Exerts Cross-Genotypic Anti-Norovirus Activity and Clears Cells from the Norovirus Replicon

2014 ◽  
Vol 58 (8) ◽  
pp. 4675-4681 ◽  
Author(s):  
J. Rocha-Pereira ◽  
M. S. J. Nascimento ◽  
Q. Ma ◽  
R. Hilgenfeld ◽  
J. Neyts ◽  
...  
Keyword(s):  
Protease Inhibitor ◽  
Antiviral Effect ◽  
Inhibitory Effect ◽  
Murine Norovirus ◽  
Norwalk Virus ◽  
Rna Dependent Rna Polymerase ◽  
Human Norovirus ◽  
Polymerase Inhibitors ◽  
Murine Noroviruses

ABSTRACTPotent and safe inhibitors of norovirus replication are needed for the treatment and prophylaxis of norovirus infections. We here report that thein vitroanti-norovirus activity of the protease inhibitor rupintrivir is extended to murine noroviruses and that rupintrivir clears human cells from their Norwalk replicon after only two passages of antiviral pressure. In addition, we demonstrate that rupintrivir inhibits the human norovirus (genogroup II [GII]) protease and further explain the inhibitory effect of the molecule by means of molecular modeling on the basis of the crystal structure of the Norwalk virus protease. The combination of rupintrivir with the RNA-dependent RNA polymerase inhibitors 2′-C-methylcytidine and favipiravir (T-705) resulted in a merely additive antiviral effect. The fact that rupintrivir is active against noroviruses belonging to genogroup I (Norwalk virus), genogroup V (murine norovirus), and the recombinant 3C-like protease of a GII norovirus suggests that the drug exerts cross-genotypic anti-norovirus activity and will thus most likely be effective against the clinically relevant human norovirus strains. The design of antiviral molecules targeting the norovirus protease could be a valuable approach for the treatment and/or prophylaxis of norovirus infections.

scholarly journals Study of Baicalin toward COVID-19 Treatment: In silico Target Analysis and in vitro Inhibitory Effects on SARS-CoV-2 Proteases

2021 ◽  
pp. 122-137
Author(s):  
Chingju Lin ◽  
Fuu-Jen Tsai ◽  
Yuan-Man Hsu ◽  
Tsung-Jung Ho ◽  
Guo-Kai Wang ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Binding Affinity ◽  
Pathway Analysis ◽  
Acute Inflammation ◽  
Inhibitory Effect ◽  
Pharmacological Effects ◽  
Inhibitory Effects ◽  
Rna Dependent Rna Polymerase ◽  
Negative Impacts

Negative impacts of COVID-19 on human health and economic and social activities urge scientists to develop effective treatments. Baicalin is a natural flavonoid, extracted from a traditional medicinal plant, previously reported with anti-inflammatory activity. In this study, we used pharmacophore fitting and molecular docking to screen and determine docking patterns and the binding affinity of baicalin on 3 major targets of SARS-CoV-2 (3-chymotrypsin-like cysteine protease [3CLpro], papain-like protease [PLpro], and RNA-dependent RNA polymerase). The obtained data revealed that baicalin has high pharmacophore fitting on 3CLpro and predicted good binding affinity on PLpro. Moreover, using the enzymatic assay, we examined the inhibitory effect of baicalin in vitro on the screened enzymes. Baicalin also exhibits inhibitory effect on these proteases in vitro. Additionally, we performed pharmacophore-based screening of baicalin on human targets and conducted pathway analysis to explore the potential cytoprotective effects of baicalin in the host cell that may be beneficial for COVID-19 treatment. The result suggested that baicalin has multiple targets in human cell that may induce multiple pharmacological effects. The result of pathway analysis implied that these targets may be associated with baicalin-induced bioactivities that are involved with signals of pro-inflammation factors, such as cytokine and chemokine. Taken together with supportive data from the literature, the bioactivities of bailalin may be beneficial for COVID-19 treatment by reducing cytokine-induced acute inflammation. In conclusion, baicalin is potentially a good candidate for developing new therapeutic to treat COVID-19.

scholarly journals Selection and Characterization of Rupintrivir-Resistant Norwalk Virus Replicon Cells In Vitro

2018 ◽  
Vol 62 (5) ◽  
Author(s):  
Mitsutaka Kitano ◽  
Myra Hosmillo ◽  
Edward Emmott ◽  
Jia Lu ◽  
Ian Goodfellow
Keyword(s):  
Reverse Genetics ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Murine Norovirus ◽  
Norwalk Virus ◽  
Irreversible Inhibitor ◽  
Antiviral Compounds ◽  
A Cell ◽  
First Time

ABSTRACT Human norovirus (HuNoV) is a major cause of nonbacterial gastroenteritis worldwide, yet despite its impact on society, vaccines and antivirals are currently lacking. A HuNoV replicon system has been widely applied to the evaluation of antiviral compounds and has thus accelerated the process of drug discovery against HuNoV infection. Rupintrivir, an irreversible inhibitor of the human rhinovirus 3C protease, has been reported to inhibit the replication of the Norwalk virus replicon via the inhibition of the norovirus protease. Here we report, for the first time, the generation of rupintrivir-resistant human Norwalk virus replicon cells in vitro . Sequence analysis revealed that these replicon cells contained amino acid substitutions of alanine 105 to valine (A105V) and isoleucine 109 to valine (I109V) in the viral protease NS6. The application of a cell-based fluorescence resonance energy transfer (FRET) assay for protease activity demonstrated that these substitutions were involved in the enhanced resistance to rupintrivir. Furthermore, we validated the effect of these mutations using reverse genetics in murine norovirus (MNV), demonstrating that a recombinant MNV strain with a single I109V substitution in the protease also showed reduced susceptibility to rupintrivir. In summary, using a combination of different approaches, we have demonstrated that, under the correct conditions, mutations in the norovirus protease that lead to the generation of resistant mutants can rapidly occur.

scholarly journals Enhanced efficacy of endonuclease inhibitor baloxavir acid against orthobunyaviruses when used in combination with ribavirin

2020 ◽  
Vol 75 (11) ◽  
pp. 3189-3193
Author(s):  
Sebastiaan ter Horst ◽  
Yaiza Fernandez-Garcia ◽  
Marcella Bassetto ◽  
Stephan Günther ◽  
Andrea Brancale ◽  
...  
Keyword(s):  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Docking Simulation ◽  
Antiviral Effect ◽  
Inhibitory Effect ◽  
Surface Model ◽  
La Crosse Virus ◽  
Endonuclease Domain ◽  
Substrate Cleavage

Abstract Objectives Baloxavir acid is an endonuclease inhibitor approved for use against influenza. We evaluated whether this compound also targets the endonuclease domain of orthobunyaviruses and therefore could potentially be used against orthobunyavirus infections. Methods We performed a thermal shift assay and a fluorescence resonance energy transfer (FRET)-based nuclease monitoring assay using the La Crosse virus (LACV) endonuclease and baloxavir acid to prove their interaction and identify an inhibitory effect. Their interaction was further studied in a docking simulation using Glide SP. We show that baloxavir acid inhibits the viral replication of Bunyamwera virus (BUNV)–mCherry in vitro using high-content imaging and virus yield assay. Lastly, we investigated the use of baloxavir acid in combination with ribavirin in vitro by implementing the Zero Interaction Potency response surface model. Results We show that baloxavir acid augments LACV enzyme’s melting temperature with ΔTm 9.5 ± 0.4°C and inhibited substrate cleavage with IC50 0.39 ± 0.03 μM. Moreover, our docking simulation suggests that baloxavir acid is able to establish an efficient binding with the LACV endonuclease. In the cell-based assay, we observed that baloxavir acid and ribavirin inhibited BUNV–mCherry with an EC50 of 0.7 ± 0.2 μM and 26.6 ± 8.9 μM, respectively. When used in combination, we found a maximum synergistic effect of 8.64. Conclusions The influenza endonuclease inhibitor baloxavir acid is able to bind to and interfere with the endonuclease domain of orthobunyaviruses and yields a more potent antiviral effect than ribavirin against BUNV–mCherry. The combination of both compounds results in a more potent antiviral effect, suggesting that these molecules could potentially be combined to treat orthobunyavirus-infected patients.

scholarly journals Attach Me If You Can: Murine Norovirus Binds to Commensal Bacteria and Fungi

Viruses ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 759 ◽  
Author(s):  
Jasmine L. Madrigal ◽  
Sutonuka Bhar ◽  
Samantha Hackett ◽  
Haley Engelken ◽  
Ross Joseph ◽  
...  
Keyword(s):  
Incubation Temperature ◽  
Growth Conditions ◽  
Fungal Species ◽  
Commensal Bacteria ◽  
Murine Norovirus ◽  
Human Norovirus ◽  
Viral Pathogens ◽  
Bacteria And Fungi ◽  
The Impact ◽  
Murine Noroviruses

The presence of commensal bacteria enhances both acute and persistent infection of murine noroviruses. For several enteric viral pathogens, mechanisms by which these bacteria enhance infection involve direct interactions between the virus and bacteria. While it has been demonstrated that human noroviruses bind to a variety of commensal bacteria, it is not known if this is also true for murine noroviruses. The goal of this study was to characterize interactions between murine noroviruses and commensal bacteria and determine the impact of bacterial growth conditions, incubation temperature and time, on murine norovirus attachment to microbes that comprise the mammalian microbiome. We show that murine noroviruses bind directly to commensal bacteria and show similar patterns of attachment as human norovirus VLPs examined under the same conditions. Furthermore, while binding levels are not impacted by the growth phase of the bacteria, they do change with time and incubation temperature. We also found that murine norovirus can bind to a commensal fungal species, Candida albicans.

scholarly journals Antiviral Effect of Korean Red Ginseng Extract and Ginsenosides on Murine Norovirus and Feline Calicivirus as Surrogates for Human Norovirus

2011 ◽  
Vol 35 (4) ◽  
pp. 429-435 ◽  
Author(s):  
Min-Hwa Lee ◽  
Bog-Hieu Lee ◽  
Ji-Youn Jung ◽  
Doo-Sung Cheon ◽  
Kyung-Tack Kim ◽  
...  
Keyword(s):  
Antiviral Effect ◽  
Feline Calicivirus ◽  
Murine Norovirus ◽  
Red Ginseng ◽  
Human Norovirus ◽  
Korean Red Ginseng ◽  
Ginseng Extract

scholarly journals Protective Role of Combined Polyphenols and Micronutrients against Influenza A Virus and SARS-CoV-2 Infection In Vitro

Biomedicines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1721
Author(s):  
Marta De Angelis ◽  
David Della-Morte ◽  
Gabriele Buttinelli ◽  
Angela Di Martino ◽  
Francesca Pacifici ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Viral Proteins ◽  
Antiviral Effect ◽  
Inhibitory Effect ◽  
Protective Role ◽  
Virus Infections ◽  
Infected Cells ◽  
Respiratory Virus Infections

Polyphenols have been widely studied for their antiviral effect against respiratory virus infections. Among these, resveratrol (RV) has been demonstrated to inhibit influenza virus replication and more recently, it has been tested together with pterostilbene against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In the present work, we evaluated the antiviral activity of polydatin, an RV precursor, and a mixture of polyphenols and other micronutrients, named A5+, against influenza virus and SARS-CoV-2 infections. To this end, we infected Vero E6 cells and analyzed the replication of both respiratory viruses in terms of viral proteins synthesis and viral titration. We demonstrated that A5+ showed a higher efficacy in inhibiting both influenza virus and SARS-CoV-2 infections compared to polydatin treatment alone. Indeed, post infection treatment significantly decreased viral proteins expression and viral release, probably by interfering with any step of virus replicative cycle. Intriguingly, A5+ treatment strongly reduced IL-6 cytokine production in influenza virus-infected cells, suggesting its potential anti-inflammatory properties during the infection. Overall, these results demonstrate the synergic and innovative antiviral efficacy of A5+ mixture, although further studies are needed to clarify the mechanisms underlying its inhibitory effect.

scholarly journals Host poly(A) polymerases PAPD5 and PAPD7 provide two layers of protection that ensure the integrity and stability of hepatitis B virus RNA

2021 ◽  
Author(s):  
Fei Liu ◽  
Amy C.H Lee ◽  
Fang Guo ◽  
Andrew S. Kondratowicz ◽  
Holly M Micolochick Steuer ◽  
...  
Keyword(s):  
Dominant Role ◽  
Regulatory Element ◽  
Rna Stability ◽  
Antiviral Effect ◽  
Inhibitory Effect ◽  
Stem Loop ◽  
Knock Out ◽  
The Individual

Noncanonical poly(A) polymerases PAPD5 and PAPD7 (PAPD5/7) stabilize HBV RNA via the interaction with the viral post-transcriptional regulatory element (PRE), representing new antiviral targets to control HBV RNA metabolism, HBsAg production and viral replication. Inhibitors targeting these proteins are being developed as antiviral therapies, therefore it is important to understand how PAPD5/7 coordinate to stabilize HBV RNA. Here, we utilized a potent small-molecule AB-452 as a chemical probe, along with genetic analyses to dissect the individual roles of PAPD5/7 in HBV RNA stability. AB-452 inhibits PAPD5/7 enzymatic activities and reduces HBsAg both in vitro (EC50 ranged from 1.4 to 6.8 nM) and in vivo by 0.93 log10. Our genetic studies demonstrate that the stem-loop alpha sequence within PRE is essential for both maintaining HBV poly(A) tail integrity and determining sensitivity towards the inhibitory effect of AB-452. Although neither single knock-out (KO) of PAPD5 nor PAPD7 reduces HBsAg RNA and protein production, PAPD5 KO does impair poly(A) tail integrity and confers partial resistance to AB-452. In contrast, PAPD7 KO could not result in any measurable phenotypic changes, but displays a similar antiviral effect as AB-452 treatment when PAPD5 is depleted simultaneously. PAPD5/7 double KO confers complete resistance to AB-452 treatment. Our results thus indicate that PAPD5 plays a dominant role in stabilizing viral RNA by protecting the integrity of its poly(A) tail, while PAPD7 serves as a second line of protection. These findings inform PAPD5 targeted therapeutic strategies and open avenues for further investigating PAPD5/7 in HBV replication.

scholarly journals 2650. Evaluating Antiviral Agents for Human Noroviruses Using a Human Intestinal Enteroid Model

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S927-S928
Author(s):  
Nicolas W Cortes-Penfield ◽  
Sasirekha Ramani ◽  
Frederick Neill ◽  
Khalil Ettayebi ◽  
Robert Atmar ◽  
...  
Keyword(s):  
Antiviral Agents ◽  
Infection Model ◽  
Dependent Manner ◽  
Murine Norovirus ◽  
Chronic Infections ◽  
Human Norovirus ◽  
Human Noroviruses ◽  
Clinical Model ◽  
Lactate Dehydrogenase Release

Abstract Background Norovirus can cause chronic infections with serious morbidity and mortality in immunocompromised patients. While there are no FDA-approved medications for these infections, nitazoxanide, ribavirin, and enterally administered pooled immunoglobulin (IVIG) are used off-label on the basis of expert opinion. Nitazoxanide and ribavirin show antiviral activity in a murine norovirus infection model and an in vitro replicon model of genotype GI.I human norovirus RNA expression, respectively. However, these drugs have not been evaluated in in vitro infections with GII.4 human noroviruses, responsible for most human norovirus disease. We used the stem cell-derived nontransformed human intestinal enteroid (HIE) system, which supports GII.4 human norovirus replication, to evaluate the antiviral activities of nitazoxanide, ribavirin, and IVIG. Methods We inoculated HIEs with GII.4 human norovirus in the presence of half-log dilutions of nitazoxanide (3 µM to 100 µM), ribavirin (10 µM to 10 mM), or IVIG (1:100 to 1:3,000) and a media control. One and 48 hours after inoculation, we extracted and quantified GII.4 norovirus RNA from the HIEs. To demonstrate that replication inhibition was not due to cytotoxicity, we performed quantitative lactate dehydrogenase release assays on the HIEs across the therapeutic range of each compound. Results Nitazoxanide reduced GII.4 replication at 48 hours in a dose-dependent manner, achieving a >90% reduction in viral replication at 10 µM without cytotoxicity. These findings were confirmed in multiple HIE lines representing different intestinal segments and established from different donors. IVIG completely inhibited GII.4 replication at up to a 1:1,000 dilution and was not cytotoxic at therapeutic concentrations. Ribavirin did not reduce GII.4 replication at concentrations up to 10 mMµM, well in excess of levels achieved in human sera with standard doses. Conclusion Nitazoxanide and IVIG, but not ribavirin, potently inhibit GII.4 human norovirus replication in a biologically relevant in vitro model of human norovirus infection. These data highlight the use of HIEs as a new pre-clinical model for developing therapeutics for human norovirus disease. Disclosures All authors: No reported disclosures.

Anti-Human Immunodeficiency Virus (HIV) Activity of the Novel Antiviral Antibiotic Quartromicins which Enhance Inhibitory Effect of 3′-azido-2′,3′-dideoxythymidine (AZT) in vitro

1992 ◽  
Vol 3 (6) ◽  
pp. 345-349 ◽  
Author(s):  
A. Tanabe-Tochikura ◽  
H. Nakashima ◽  
T. Murakami ◽  
O. Tenmyo ◽  
T. Oki ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Specific Antigen ◽  
Antigen Expression ◽  
Antiviral Effect ◽  
Inhibitory Effect ◽  
Reverse Transcriptase Activity ◽  
The Novel ◽  
Avian Myeloblastosis Virus ◽  
Immunodeficiency Virus

Novel antiviral antibiotic quartromicins A1 and D1, isolated from Amycolatopsis orientalis, significantly inhibited human immunodeficiency virus (HIV)-induced cytopathic effect and virus specific antigen expression at concentrations of 25–100 μg ml−1 In MT-4 cells infected with HTLV-IIIB. The reverse transcriptase activity of disrupted HTLV-IIIB particles, recombinant HIV-1 enzyme, and purified avian myeloblastosis virus (AMV) enzyme were also significantly inhibited by quartromicins A1 and D1. The combined antiviral effect of quartromicin A1 and AZT on the replication of HIV in MT-4 cells was also examined. Quartromicin A1 synergistically enhanced the inhibitory effect of AZT as revealed by HIV-specific antigen expression.

scholarly journals Antiviral Activity ofIsatis indigoticaExtract and Its Derived Indirubin against Japanese Encephalitis Virus

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Shu-Jen Chang ◽  
Yi-Chih Chang ◽  
Kai-Zen Lu ◽  
Yi-Yun Tsou ◽  
Cheng-Wen Lin
Keyword(s):  
Antiviral Activity ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Antiviral Effect ◽  
Inhibitory Effect ◽  
Encephalitis Virus ◽  
Simultaneous Treatment ◽  
Virus Attachment ◽  
Antiviral Activities

Isatis indigoticais widely used in Chinese Traditional Medicine for clinical treatment of virus infection, tumor, and inflammation, yet its antiviral activities remain unclear. This study probed antiviral activity ofI. indigoticaextract and its marker compounds against Japanese encephalitis virus (JEV).I. indigoticamethanol extract, indigo, and indirubin proved less cytotoxic than other components, showing inhibitory effect (concentration-dependent) on JEV replicationin vitro. Time-of-addition experiments proved the extract, indigo, and indirubin with potent antiviral effect by pretreatment (before infection) or simultaneous treatment (during infection), but not posttreatment (after entry). Antiviral action of these agents showed correlation with blocking virus attachment and exhibited potent virucidal activity. In particular, indirubin had strong protective ability in a mouse model with lethal JEV challenge. The study could yield anti-JEV agents.

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