Substituted 2,6-bis(benzimidazol-2-yl)pyridines: A novel chemical class of pestivirus inhibitors that targets a hot spot for inhibition of pestivirus replication in the RNA-dependent RNA polymerase

• Published in: Antiviral research Vol. 106; pp. 71 - 79
• Main Authors: Musiu, Simone, Pürstinger, Gerhard, Stallinger, Sylvia, Vrancken, Robert, Haegeman, Andy, Koenen, Frank, Leyssen, Pieter, Froeyen, Mathy, Neyts, Johan, Paeshuyse, Jan
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01-06-2014; Elsevier
• Subjects: Animals; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antiviral agents; Antiviral Agents - chemistry; Antiviral Agents - isolation & purification; Antiviral Agents - pharmacology; Antiviral Agents - toxicity; Benzimidazoles - chemistry; Benzimidazoles - isolation & purification; Benzimidazoles - pharmacology; Benzimidazoles - toxicity; Biological and medical sciences; Bovine viral diarrhea virus; Cattle; Cell Line; Classical swine fever virus; Classical swine fever virus - drug effects; Classical swine fever virus - enzymology; Diarrhea Virus 1, Bovine Viral - drug effects; Diarrhea Virus 1, Bovine Viral - enzymology; Drug Resistance, Viral; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - isolation & purification; Enzyme Inhibitors - pharmacology; Enzyme Inhibitors - toxicity; Flaviviridae; Hepacivirus - drug effects; Hepacivirus - enzymology; Hepatitis C virus; Medical sciences; Models, Molecular; Mutation; Pestivirus; Pharmacology. Drug treatments; Protein Conformation; Pyridines - chemistry; Pyridines - isolation & purification; Pyridines - pharmacology; Pyridines - toxicity; RNA Replicase - antagonists & inhibitors; RNA-dependent RNA polymerase; Substituted 2,6-bis(benzimidazol-2-yl)pyridine inhibitors; Virus Replication - drug effects; Substituted 2,6-bis(benzimidazol-2-yl)pyridine inhibitors; Bovine viral diarrhea virus; RNA-dependent RNA polymerase; Pestivirus; Targeting; Enzyme; Transferases; Hot spot; RNA-directed RNA polymerase; Virus; Nucleotidyltransferases; Target; Bovine diarrhea virus; Replication; Inhibitor; Inhibition; Flaviviridae; Veterinary
• ISSN: 0166-3542; 1872-9096
• DOI: 10.1016/j.antiviral.2014.03.010

•BBP is a selective inhibitor of BVDV and CSFV replication.•Resistant viruses carry mutation I261M for BVDV or I261N/P262A for CSFV in the RdRp.•BBP-resistant pestiviruses show cross-resistant to known pestivirus inhibitors.•Inactive in an in vitro BVDV RdRp assay.•BBP does inhibit the activity of BVDV replication complexes.
2,6-Bis(benzimidazol-2-yl)pyridine (BBP/CSFA-0) was identified in a CPE-based screening as a selective inhibitor of the in vitro bovine viral diarrhea virus (BVDV) replication. The EC50-values for the inhibition of BVDV-induced cytopathic (CPE) effect, viral RNA synthesis and the production of infectious virus were 0.3±0.1μM, 0.05±0.01μM and 0.3±0.04μM, respectively. Furthermore, BBP/CSFA-0 inhibits the in vitro replication of the classical swine fever virus (CSFV) with an EC50 of 0.33±0.25μM. BBP/CSFA-0 proved in vitro inactive against the hepatitis C virus, that belongs like BVDV and CSFV to the family of Flaviviridae. Modification of the substituents on the two 1H-benzimidazole groups of BBP resulted in analogues equipotent in anti-BVDV activity (EC50=0.7±0.1μM), devoid of cytotoxicity (S.I.=142). BBP resistant BVDV was selected for and was found to carry the I261M mutation in the viral RNA-dependent RNA polymerase (RdRp). Likewise, BBP-resistant CSFV was selected for; this variant carries either an I261N or a P262A mutation in NS5B. Molecular modeling revealed that I261 and P262 are located in a small cavity near the fingertip domain of the pestivirus polymerase. BBP-resistant BVDV and CSFV proved to be cross-resistant to earlier reported pestivirus inhibitors (BPIP, AG110 and LZ37) that are known to target the same region of the RdRp. BBP did not inhibit the in vitro activity of recombinant BVDV RdRp but inhibited the activity of BVDV replication complexes (RCs). BBP interacts likely with the fingertip of the pestivirus RdRp at the same position as BPIP, AG110 and LZ37. This indicates that this region is a “hot spot” for inhibition of pestivirus replication.