Triaryl pyrazoline compound inhibits flavivirus RNA replication.
Triaryl pyrazoline {[5-(4-chloro-phenyl)-3-thiophen-2-yl-4,5-dihydro-pyrazol-1-yl]-phenyl-methanone} inhibits flavivirus infection in cell culture. The inhibitor was identified through high-throughput screening of a compound library using a luciferase-expressing West Nile (WN) virus infection assay. The compound inhibited an epidemic strain of WN virus without detectable cytotoxicity (a 50% effective concentration of 28 microM and a compound concentration of >or=300 microM required to reduce 50% cell viability). Besides WN virus, the compound also inhibited other flaviviruses (dengue, yellow fever, and St. Louis encephalitis viruses), an alphavirus (Western equine encephalitis virus), a coronavirus (mouse hepatitis virus), and a rhabdovirus (vesicular stomatitis virus). However, the compound did not suppress an orthomyxovirus (influenza virus) or a retrovirus (human immunodeficiency virus type 1). Mode-of-action analyses in WN virus showed that the compound did not inhibit viral entry or virion assembly but specifically suppressed viral RNA synthesis. To examine the mechanism of inhibition of dengue virus, we developed two replicon systems for dengue type 1 virus: (i) a stable cell line that harbored replicons containing a luciferase reporter and a neomycin phosphotransferase selection marker and (ii) a luciferase-expressing replicon that could differentiate between viral translation and RNA replication. Analyses of the compound in the dengue type 1 virus replicon systems showed that it weakly suppressed viral translation but significantly inhibited viral RNA synthesis. Overall, the results demonstrate that triaryl pyrazoline exerts a broad spectrum of antiflavivirus activity through potent inhibition of viral RNA replication. This novel inhibitor could be developed for potential treatment of flavivirus infection.
Puig-Basagoiti
Francesc
F
Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA.
Tilgner
Mark
M
Forshey
Brett M
BM
Philpott
Sean M
SM
Espina
Noel G
NG
Wentworth
David E
DE
Goebel
Scott J
SJ
Masters
Paul S
PS
Falgout
Barry
B
Ren
Ping
P
Ferguson
David M
DM
Shi
Pei-Yong
PY
D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002522:Chlorocebus aethiops; D003716:Dengue Virus / Q000187:drug effects / Q000235:genetics; D005416:Flavivirus / Q000187:drug effects* / Q000235:genetics; D011720:Pyrazoles / Q000494:pharmacology; D012367:RNA, Viral / Q000096:biosynthesis*; D014709:Vero Cells; D014779:Virus Replication / Q000187:drug effects; D014902:West Nile virus / Q000187:drug effects / Q000235:genetics
D000998:Antiviral Agents; D011720:Pyrazoles; D012367:RNA, Viral