title: Inhibitors of the IMPDH enzyme as potential anti-bovine viral diarrhoea virus agents.
abstract: Ribavirin and mycophenolic acid (MPA) are known inhibitors of the IMPDH enzyme (E.C. 1.1.1.205). This enzyme catalyzes the conversion of inosine monophosphate to xanthine monophosphate, leading eventually to a decrease in the intracellular level of GTP and dGTP. The antiviral effect against bovine viral diarrhoea virus (BVDV) of 15 analogues related to MPA was determined. MDBK cells were infected with the cytopathic strain of BVDV in presence or absence of test compounds. Viral RNA was extracted from the cell supernatant fluids and quantified by RT-PCR. Ribavirin showed a potent antiviral effect against BVDV with 90% effective concentration (EC90) of 4 microM. MPA along with several analogues, including both its corresponding aldehyde and alcohol, and modifications in the length of the side chain (C2- and C4-derivatives) were tested. We have identified previously unreported IMPDH inhibitors that have potent anti-BVDV activity, namely: C6-MPAlc (5), C6-MPA-Me (7), C4-MPAlc (8), C4-MPA (10) and C2-MAD (20). Most of these compounds inhibited the IMPDH enzyme in the nanomolar range (4-800 nM) in cell-free assays. Some compounds, such as mizoribine, which is a potent inhibitor of IMPDH in vitro (enzyme 50% inhibitory concentration IC50=4 nM), had no detectable anti-BVDV activity up to 100 microM. The compounds were essentially non-toxic to a confluent monolayer of MDBK cells. However, in exponentially growing cells, they showed minimal toxicity at 100 microM over a 24 h period, but the toxicity was more pronounced after 3 days [50% cytotoxic concentration (CC50) value ranged from 5 to 30 microM].
authors.affiliation: Pharmasset Inc., Tucker, GA, USA. lstuyver@pharmasset.com
authors.forename: Lieven J
authors.initials: LJ
authors.lastname: Stuyver
authors.forename: Stefania
authors.initials: S
authors.lastname: Lostia
authors.forename: Steven E
authors.initials: SE
authors.lastname: Patterson
authors.forename: Jeremy L
authors.initials: JL
authors.lastname: Clark
authors.forename: Kyoichi A
authors.initials: KA
authors.lastname: Watanabe
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Otto
authors.forename: Krzysztof W
authors.initials: KW
authors.lastname: Pankiewicz
mesh_terms: D000818:Animals; D002417:Cattle; D002460:Cell Line / Q000187:drug effects / Q000821:virology; D003199:Computer Systems; D017077:Culture Media, Conditioned; D001908:Diarrhea Viruses, Bovine Viral / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D015195:Drug Design; D004353:Drug Evaluation, Preclinical; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D006160:Guanosine Triphosphate / Q000378:metabolism; D007168:IMP Dehydrogenase / Q000037:antagonists & inhibitors*; D007668:Kidney; D015394:Molecular Structure; D009173:Mycophenolic Acid / Q000031:analogs & derivatives / Q000494:pharmacology*; D009243:NAD / Q000031:analogs & derivatives / Q000494:pharmacology; D009705:Nucleosides / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012254:Ribavirin / Q000031:analogs & derivatives / Q000494:pharmacology*; D012263:Ribonucleosides / Q000494:pharmacology; D010948:Viral Plaque Assay; D014779:Virus Replication / Q000187:drug effects
chemical_list: D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D009705:Nucleosides; D012263:Ribonucleosides; D009243:NAD; C076145:3-(1-deoxyribofuranosyl)benzamide; D012254:Ribavirin; C010052:mizoribine; D006160:Guanosine Triphosphate; D007168:IMP Dehydrogenase; D009173:Mycophenolic Acid; C033706:tiazofurin