Potential Therapeutic Agents for Feline Calicivirus Infection

Tulio M Fumian; Daniel Enosi Tuipulotu; Natalie E Netzler; Jennifer H Lun; Alice G Russo; Grace J H Yan; Peter A White

doi:10.3390/v10080433

Potential Therapeutic Agents for Feline Calicivirus Infection

Viruses. 2018 Aug 16;10(8):433. doi: 10.3390/v10080433.

Authors

Tulio M Fumian^{1

2}, Daniel Enosi Tuipulotu³, Natalie E Netzler⁴, Jennifer H Lun⁵, Alice G Russo⁶, Grace J H Yan⁷, Peter A White⁸

Affiliations

¹ School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, NSW 2052, Australia. [email protected].
² Laboratório de Virologia Comparada e Ambiental, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro 21040-900, Brazil. [email protected].
³ School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, NSW 2052, Australia. [email protected].
⁴ School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, NSW 2052, Australia. [email protected].
⁵ School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, NSW 2052, Australia. [email protected].
⁶ School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, NSW 2052, Australia. [email protected].
⁷ School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, NSW 2052, Australia. [email protected].
⁸ School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, NSW 2052, Australia. [email protected].

Abstract

Feline calicivirus (FCV) is a major cause of upper respiratory tract disease in cats, with widespread distribution in the feline population. Recently, virulent systemic diseases caused by FCV infection has been associated with mortality rates up to 50%. Currently, there are no direct-acting antivirals approved for the treatment of FCV infection. Here, we tested 15 compounds from different antiviral classes against FCV using in vitro protein and cell culture assays. After the expression of FCV protease-polymerase protein, we established two in vitro assays to assess the inhibitory activity of compounds directly against the FCV protease or polymerase. Using this recombinant enzyme, we identified quercetagetin and PPNDS as inhibitors of FCV polymerase activity (IC₅₀ values of 2.8 μM and 2.7 μM, respectively). We also demonstrate the inhibition of FCV protease activity by GC376 (IC₅₀ of 18 µM). Using cell culture assays, PPNDS, quercetagetin and GC376 did not display antivirals effects, however, we identified nitazoxanide and 2'-C-methylcytidine (2CMC) as potent inhibitors of FCV replication, with EC₅₀ values in the low micromolar range (0.6 μM and 2.5 μM, respectively). In conclusion, we established two in vitro assays that will accelerate the research for FCV antivirals and can be used for the high-throughput screening of direct-acting antivirals.

Keywords: antivirals; feline calicivirus; non-nucleoside inhibitors; nucleoside analogues; protease inhibitors.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Antiviral Agents / pharmacology*
Caliciviridae Infections / drug therapy
Caliciviridae Infections / veterinary
Caliciviridae Infections / virology
Calicivirus, Feline / drug effects*
Calicivirus, Feline / genetics
Calicivirus, Feline / metabolism
Cat Diseases / drug therapy
Cat Diseases / virology
Cats
Cell Line
Cytidine / analogs & derivatives*
Cytidine / pharmacology
DNA-Directed RNA Polymerases / antagonists & inhibitors*
DNA-Directed RNA Polymerases / genetics
DNA-Directed RNA Polymerases / metabolism
Epithelial Cells / drug effects
Epithelial Cells / virology
Flavones / pharmacology
Gene Expression
High-Throughput Screening Assays
Inhibitory Concentration 50
Nitro Compounds
Peptide Hydrolases / genetics
Peptide Hydrolases / metabolism*
Polyproteins / antagonists & inhibitors*
Polyproteins / genetics
Polyproteins / metabolism
Pyridoxal Phosphate / analogs & derivatives
Pyridoxal Phosphate / pharmacology
Recombinant Proteins / genetics
Recombinant Proteins / metabolism
Respiratory Tract Infections / drug therapy
Respiratory Tract Infections / veterinary
Respiratory Tract Infections / virology
Sulfonic Acids / pharmacology
Thiazoles / pharmacology*

Substances

Antiviral Agents
Flavones
Nitro Compounds
Polyproteins
Recombinant Proteins
Sulfonic Acids
Thiazoles
pyridoxal-5'-phosphate-6-(2'-naphthylazo-6'-nitro-4',8'-disulfonate)
2'-C-methylcytidine
Cytidine
Pyridoxal Phosphate
DNA-Directed RNA Polymerases
Peptide Hydrolases
nitazoxanide
quercetagetin