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PLoS Negl Trop Dis. 2016 Mar 14;10(3):e0004524. doi: 10.1371/journal.pntd.0004524. eCollection 2016 Mar.

Iminosugars Inhibit Dengue Virus Production via Inhibition of ER Alpha-Glucosidases--Not Glycolipid Processing Enzymes.

Author information

1
Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford, United Kingdom.
2
Division of Infectious Diseases and Vaccinology, School of Public Health, University of California-Berkeley, Berkeley, California, United States of America.
3
Department of Hospital Pharmacy, University of Toyama, Toyama, Japan.

Abstract

It has long been thought that iminosugar antiviral activity is a function of inhibition of endoplasmic reticulum-resident α-glucosidases, and on this basis, many iminosugars have been investigated as therapeutic agents for treatment of infection by a diverse spectrum of viruses, including dengue virus (DENV). However, iminosugars are glycomimetics possessing a nitrogen atom in place of the endocyclic oxygen atom, and the ubiquity of glycans in host metabolism suggests that multiple pathways can be targeted via iminosugar treatment. Successful treatment of patients with glycolipid processing defects using iminosugars highlights the clinical exploitation of iminosugar inhibition of enzymes other than ER α-glucosidases. Evidence correlating antiviral activity with successful inhibition of ER glucosidases together with the exclusion of alternative mechanisms of action of iminosugars in the context of DENV infection is limited. Celgosivir, a bicyclic iminosugar evaluated in phase Ib clinical trials as a therapeutic for the treatment of DENV infection, was confirmed to be antiviral in a lethal mouse model of antibody-enhanced DENV infection. In this study we provide the first evidence of the antiviral activity of celgosivir in primary human macrophages in vitro, in which it inhibits DENV secretion with an EC50 of 5 μM. We further demonstrate that monocyclic glucose-mimicking iminosugars inhibit isolated glycoprotein and glycolipid processing enzymes and that this inhibition also occurs in primary cells treated with these drugs. By comparison to bicyclic glucose-mimicking iminosugars which inhibit glycoprotein processing but do not inhibit glycolipid processing and galactose-mimicking iminosugars which do not inhibit glycoprotein processing but do inhibit glycolipid processing, we demonstrate that inhibition of endoplasmic reticulum-resident α-glucosidases, not glycolipid processing, is responsible for iminosugar antiviral activity against DENV. Our data suggest that inhibition of ER α-glucosidases prevents release of virus and is the primary antiviral mechanism of action of iminosugars against DENV.

PMID:
26974655
PMCID:
PMC4790851
DOI:
10.1371/journal.pntd.0004524
[Indexed for MEDLINE]
Free PMC Article

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