Skip to Content
Merck
  • Identification and characterisation of small molecule inhibitors of feline coronavirus replication.

Identification and characterisation of small molecule inhibitors of feline coronavirus replication.

Veterinary microbiology (2014-12-04)
Phillip McDonagh, Paul A Sheehy, Jacqueline M Norris
ABSTRACT

Feline infectious peritonitis (FIP), a feline coronavirus (FCoV) induced disease, is almost invariably fatal with median life expectancy measured in days. Current treatment options are, at best, palliative. The objectives of this study were to evaluate a panel of nineteen candidate compounds for antiviral activity against FCoV in vitro to determine viable candidates for therapy. A resazurin-based cytopathic effect inhibition assay, which detects viable cells through their reduction of the substrate resazurin to fluorescent resorufin, was developed for screening compounds for antiviral efficacy against FCoV. Plaque reduction and virus yield reduction assays were performed to confirm antiviral effects of candidate compounds identified during screening, and the possible antiviral mechanisms of action of these compounds were investigated using virucidal suspension assays and CPE inhibition and IFA-based time of addition assays. Three compounds, chloroquine, mefloquine, and hexamethylene amiloride demonstrated marked inhibition of virus induced CPE at low micromolar concentrations. Orthogonal assays confirmed inhibition of CPE was associated with significant reductions in viral replication. Selectivity indices calculated based on in vitro cytotoxicity screening and reductions in extracellular viral titre were 217, 24, and 20 for chloroquine, mefloquine, and hexamethylene amiloride respectively. Preliminary experiments performed to inform the antiviral mechanism of the compounds demonstrated all three acted at an early stage of viral replication. These results suggest that these direct acting antiviral compounds, or their derivatives, warrant further investigation for clinical use in cats with FIP.

MATERIALS
Product Number
Brand
Product Description

Supelco
Dimethyl sulfoxide, for inorganic trace analysis, ≥99.99995% (metals basis)
Sigma-Aldrich
8-Octanoyloxypyrene-1,3,6-trisulfonic acid trisodium salt, suitable for fluorescence, ≥90% (HPCE)
Sigma-Aldrich
Dimethyl sulfoxide, ≥99.5% (GC), suitable for plant cell culture
Sigma-Aldrich
Dimethyl sulfoxide, meets EP testing specifications, meets USP testing specifications
Sigma-Aldrich
Dimethyl sulfoxide, Hybri-Maxā„¢, sterile-filtered, BioReagent, suitable for hybridoma, ā‰„99.7%
Sigma-Aldrich
Dimethyl sulfoxide, PCR Reagent
Sigma-Aldrich
Dimethyl sulfoxide, BioUltra, for molecular biology, ≥99.5% (GC)
Sigma-Aldrich
Dimethyl sulfoxide, for molecular biology
Sigma-Aldrich
Dimethyl sulfoxide, ReagentPlusĀ®, ā‰„99.5%
Sigma-Aldrich
DAPI, for nucleic acid staining
Sigma-Aldrich
Dimethyl sulfoxide, anhydrous, ≥99.9%
Sigma-Aldrich
Dimethyl sulfoxide, puriss. p.a., ACS reagent, ≥99.9% (GC)
Supelco
Dimethyl sulfoxide, analytical standard
Sigma-Aldrich
Dimethyl sulfoxide, sterile-filtered, BioPerformance Certified, meets EP, USP testing specifications, suitable for hybridoma
Sigma-Aldrich
Dimethyl sulfoxide, ACS reagent, ≥99.9%
Sigma-Aldrich
Dimethyl sulfoxide, Vetecā„¢, reagent grade, 99%
USP
Dimethyl sulfoxide, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
Dimethyl sulfoxide, puriss. p.a., dried, ≤0.02% water
Dimethyl sulfoxide, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
Dimethyl sulfoxide, suitable for HPLC, ≥99.7%