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    Characterizing Loop Dynamics and Ligand Recognition in Human- and Avian-Type Influenza Neuraminidases via Generalized Born Molecular Dynamics and End-Point Free Energy Calculations
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    Abstract:
    The comparative dynamics and inhibitor binding free energies of group-1 and group-2 pathogenic influenza A subtype neuraminidase (NA) enzymes are of fundamental biological interest and relevant to structure-based drug design studies for antiviral compounds. In this work, we present seven generalized Born molecular dynamics simulations of avian (N1)- and human (N9)-type NAs in order to probe the comparative flexibility of the two subtypes, both with and without the inhibitor oseltamivir bound. The enhanced sampling obtained through the implicit solvent treatment suggests several provocative insights into the dynamics of the two subtypes, including that the group-2 enzymes may exhibit similar motion in the 430-binding site regions but different 150-loop motion. End-point free energy calculations elucidate the contributions to inhibitor binding free energies and suggest that entropic considerations cannot be neglected when comparing across the subtypes. We anticipate the findings presented here will have broad implications for the development of novel antiviral compounds against both seasonal and pandemic influenza strains.
    Keywords:
    Neuraminidase inhibitor
    Dynamics
    For many years, antiviral treatment of influenza has consisted of monotherapy with a neuraminidase inhibitor. The Food and Drug Administration (FDA) approved the neuraminidase inhibitors oseltamivir (oral administration) and zanamivir (oral inhalation) in 1999 and peramivir (intravenous administration) in late 2014. These drugs work by binding to the viral neuraminidase protein and interfering with the release of influenza virus particles from infected respiratory tract cells. Neuraminidase inhibitors are FDA-approved for the treatment of uncomplicated influenza within 2 days after onset in outpatients, on the basis of randomized, controlled trials, but they are also recommended for the treatment of patients with . . .
    Zanamivir
    Neuraminidase inhibitor
    Oseltamivir
    Citations (11)
    Two hundred and forty-five human influenza A and B viruses isolated in Australia between 1996 and 2003 were tested for their sensitivity to the NA inhibitor drugs, zanamivir and oseltamivir using a fluorescence-based neuraminidase inhibition assay. Based on mean IC50 values, influenza A viruses (with neuraminidase subtypes N1 and N2) were more sensitive to both the NA inhibitors than were influenza B strains. Influenza A viruses with a N1 subtype and influenza B strains both demonstrated a greater sensitivity to zanamivir than to oseltamivir carboxylate, whereas influenza A strains with a N2 subtype were more susceptible to oseltamivir carboxylate. A comparison of IC50 values for viruses isolated before and after the release of the NA inhibitors in Australia, found there was no significant difference in the sensitivity of strains to either neuraminidase inhibitor and none of the isolates tested showed clinically significant resistance.
    Zanamivir
    Oseltamivir
    Neuraminidase inhibitor
    IC50
    Human influenza
    Sialidase
    Citations (12)
    Preview this article: Authors' response: Highly pathogenic influenza A(H5N1) viruses in farmed mink outbreak contain a disrupted second sialic acid binding site in neuraminidase, similar to human influenza A viruses, Page 1 of 1 < Previous page | Next page > /docserver/preview/fulltext/eurosurveillance/28/7/eurosurv-28-7-6-1.gif
    Human influenza
    H5N1 genetic structure
    Sialidase
    Highly pathogenic
    The neuraminidase inhibitors are a class of antiviral drugs used for both the prophylaxis and treatment of influenza infections. Clinical trials of these inhibitors detected a low level of resistant viruses from treated individuals, although a higher frequency was detected in children (5%-6%) compared to adults (1%-4%). In addition, there have been some previous reports of NA inhibitor resistant viruses being isolated from untreated individuals. Here we report on the NA inhibitor sensitivity of over 1,000 influenza isolates collected through the World Health Organization (WHO) global influenza surveillance program. Of the total number of viruses analysed, only 2 (0.2%) strains (an A(H1N1) strain and an influenza B strain) were considered to have a significant reduction in sensitivity to at least one of the neuraminidase inhibitor drugs. Interestingly, both of these strains were isolated from untreated patients in the youngest age cohort (less than 2 years). Although the influenza B strain is unlikely to be clinically resistant, the A(H1N1) virus contained the same His274Tyr neuraminidase mutation that has been observed in resistant mutants following oseltamivir treatment. Given these results it may be important to enhance neuraminidase inhibitor susceptibility testing of viruses from patients in the less than two years cohort.
    Neuraminidase inhibitor
    Oseltamivir
    Citations (24)
    Nowadays, influenza has become a global public health concern because it is responsible for significant morbidity and mortality due to annual epidemics and unpredictable pandemics. There are only limited options to control this respiratory disease. Vaccine treatment is useless for controlling this disease because of the occurrence of mutation in the influenza virus. Influenza virus is also resistant to some antiviral drugs like oseltamivir and zanamivir, which inhibit neuraminidase. Another solution for controlling this virus is to find new design for antiviral drugs. Cyclic peptides can be used to make new antiviral drug design especially to inhibit neuraminidase activity by using ’structure-based design’ method. Based on molecular docking, new antiviral drug designs have been found. They are DNY, NNY, DDY, DYY, RRR, RPR, RRP and LRL. These cyclic peptides showed better activity and affinity than standard ligand to inhibit neuraminidase activity. From drug scan, DNY, NNY and LRL ligands have low toxicity and were predicted to have at least 59% possibility that it could be synthesized in wet laboratory experiment. Key words : Influenza virus A, neuraminidase, cyclic peptide, structure based design, molecular docking.
    Zanamivir
    Oseltamivir
    Neuraminidase inhibitor
    Docking (animal)
    Antiviral drug
    Citations (16)
    We have recently reported an influenza virus neuraminidase inhibitor, RWJ-270201 (BCX-1812), a novel cyclopentane derivative discovered through structure-based drug design. In this paper, we compare the potency of three compounds, RWJ-270201, oseltamivir, and zanamivir, against neuraminidase enzymes from various subtypes of influenza. RWJ-270201 effectively inhibited all tested influenza A and influenza B neuraminidases in vitro, with 50% inhibitory concentrations of 0.09 to 1.4 nM for influenza A neuraminidases and 0.6 to 11 nM for influenza B neuraminidases. These values were comparable to or lower than those for oseltamivir carboxylate (GS4071) and zanamivir (GG167). RWJ-270201 demonstrated excellent selectivity (>10,000-fold) for influenza virus neuraminidase over mammalian, bacterial, or other viral neuraminidases. Oral administration of a dosage of 1 mg/kg of body weight/day of RWJ-270201 for 5 days (beginning 4 h preinfection) showed efficacy in the murine model of influenza virus infection as determined by lethality and weight loss protection. RWJ-270201 administered intranasally at 0.01 mg/kg/day in the murine influenza model demonstrated complete protection against lethality, whereas oseltamivir carboxylate and zanamivir at the same dose demonstrated only partial protection. In the delayed-treatment murine influenza model, oral administration of a 10-mg/kg/day dose of RWJ-270201 or oseltamivir (GS4104, a prodrug of GS4071) at 24 h postinfection showed significant protection against lethality (P < 0.001 versus control). However, when the treatment was delayed for 48 h, no significant protection was observed in either drug group. No drug-related toxicity was observed in mice receiving 100 mg/kg/day of RWJ-270201 for 5 days. These efficacy and safety profiles justify further consideration of RWJ-270201 for the treatment and prevention of human influenza.
    Zanamivir
    Oseltamivir
    Neuraminidase inhibitor
    On Oct 28, the results of two US trials were published showing that Roche's oral neuraminidase inhibitor oseltamivir is effective in preventing influenza in healthy adults. And the day before, the US FDA approved oseltamivir for the treatment of influenza types A and B.
    Oseltamivir
    Neuraminidase inhibitor