A novel, highly selective inhibitor of pestivirus replication that targets the viral RNA-dependent RNA polymerase.
We report on the highly potent and selective antipestivirus activity of 5-[(4-bromophenyl)methyl]-2-phenyl-5H-imidazo[4,5-c]pyridine (BPIP). The 50% effective concentration (EC50) for inhibition of bovine viral diarrhea virus (BVDV)-induced cytopathic effect formation was 0.04 +/- 0.01 microM. Comparable reduction of viral RNA synthesis (EC50 = 0.12 +/- 0.02 microM) and production of infectious virus (EC50= 0.074 +/- 0.003 microM) were observed. The selectivity index (ratio of 50% cytostatic concentration/EC50) of BPIP was approximately 2,000. BPIP was inactive against the hepatitis C virus subgenomic replicon and yellow fever virus but demonstrated weak activity against GB virus. Drug-resistant mutants were at least 300-fold less susceptible to BPIP than wild-type virus; showed cross-resistance to N-propyl-N-[2-(2H-1,2,4-triazino[5,6-b]indol-3-ylthio)ethyl]-1-propanamine (VP32947), and carried the F224S mutation in the viral RNA-dependent RNA polymerase (RdRp). When the F224S mutation was introduced into an infectious clone, the drug-resistant phenotype was obtained. BPIP did not inhibit the in vitro activity of recombinant BVDV RdRp, but did inhibit the activity of replication complexes (RCs). Computational docking revealed that F224 is located at the top of the finger domain of the polymerase. Docking of BPIP in the crystal structure of the BVDV RdRp revealed aromatic ring stacking, some hydrophobic contacts, and a hydrogen bond. Since two structurally unrelated compounds, i.e., BPIP and VP32947, target the same region of the BVDV RdRp, this position may be expected to be critical in the functioning of the polymerase or assembly of the RC. The potential of BPIP for the treatment of pestivirus and hepacivirus infections is discussed.
Paeshuyse
Jan
J
Rega Institute for Medical Research, Minderbroedersstraat 10, B-3000 Leuven, Belgium.
Leyssen
Pieter
P
Mabery
Eric
E
Boddeker
Nina
N
Vrancken
Robert
R
Froeyen
Matheus
M
Ansari
Israrul H
IH
Dutartre
Hélène
H
Rozenski
Jef
J
Gil
Laura H V G
LH
Letellier
Carine
C
Lanford
Robert
R
Canard
Bruno
B
Koenen
Frank
F
Kerkhofs
Pierre
P
Donis
Ruben O
RO
Herdewijn
Piet
P
Watson
Julia
J
De Clercq
Erik
E
Puerstinger
Gerhard
G
Neyts
Johan
J
D000998:Antiviral Agents / Q000494:pharmacology*; D030241:Diarrhea Virus 1, Bovine Viral / Q000187:drug effects; D024882:Drug Resistance, Viral; D007093:Imidazoles / Q000494:pharmacology; D007928:Lethal Dose 50; D009154:Mutation; D010576:Pestivirus / Q000187:drug effects* / Q000502:physiology; D011725:Pyridines / Q000494:pharmacology; D012367:RNA, Viral / Q000096:biosynthesis; D012324:RNA-Dependent RNA Polymerase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D014227:Triazines / Q000737:chemistry / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D014779:Virus Replication / Q000187:drug effects*
C516398:5-((4-bromophenyl)methyl)-2-phenyl-5H-imidazo(4,5-c)pyridine; D000998:Antiviral Agents; D007093:Imidazoles; D011725:Pyridines; D012367:RNA, Viral; D014227:Triazines; D012324:RNA-Dependent RNA Polymerase