title: Inhibition of viral protein translation by indomethacin in vesicular stomatitis virus infection: role of eIF2α kinase PKR.
abstract: Indomethacin, a cyclooxygenase-1 and -2 inhibitor widely used in the clinic for its potent anti-inflammatory/analgesic properties, possesses antiviral activity against several viral pathogens; however, the mechanism of antiviral action remains elusive. We have recently shown that indomethacin activates the double-stranded RNA (dsRNA)-dependent protein kinase R (PKR) in human colon cancer cells. Because of the important role of PKR in the cellular defence response against viral infection, herein we investigated the effect of indomethacin on PKR activity during infection with the prototype rhabdovirus vesicular stomatitis virus. Indomethacin was found to activate PKR in an interferon- and dsRNA-independent manner, causing rapid (< 5 min) phosphorylation of eukaryotic initiation factor-2 α-subunit (eIF2α). These events resulted in shutting off viral protein translation and blocking viral replication (IC50  = 2 μM) while protecting host cells from virus-induced damage. Indomethacin did not affect eIF2α kinases PKR-like endoplasmic reticulum-resident protein kinase (PERK) and general control non-derepressible-2 (GCN2) kinase, and was unable to trigger eIF2α phosphorylation in the presence of PKR inhibitor 2-aminopurine. In addition, small-interfering RNA-mediated PKR gene silencing dampened the antiviral effect in indomethacin-treated cells. The results identify PKR as a critical target for the antiviral activity of indomethacin and indicate that eIF2α phosphorylation could be a key element in the broad spectrum antiviral activity of the drug.
authors: Department of Biology, University of Rome Tor Vergata, Rome, Italy.
authors: Carla
authors: C
authors: Amici
authors: Department of Biology, University of Rome Tor Vergata, Rome, Italy.
authors: Simone
authors: S
authors: La Frazia
authors: Department of Biology, University of Rome Tor Vergata, Rome, Italy.
authors: Claudia
authors: C
authors: Brunelli
authors: Department of Biology, University of Rome Tor Vergata, Rome, Italy.
authors: Mirna
authors: M
authors: Balsamo
authors: Department of Biology, University of Rome Tor Vergata, Rome, Italy.
authors: Mara
authors: M
authors: Angelini
authors: Department of Biology, University of Rome Tor Vergata, Rome, Italy.|Institute of Translational Pharmacology, CNR, Rome, Italy.
authors: M Gabriella
authors: MG
authors: Santoro
mesh_terms: D000998:Antiviral Agents / Q000378:metabolism*; D002460:Cell Line; D020536:Enzyme Activators / Q000378:metabolism; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism*; D006801:Humans; D007213:Indomethacin / Q000378:metabolism*; D020128:Inhibitory Concentration 50; D010766:Phosphorylation; D014176:Protein Biosynthesis / Q000187:drug effects*; D011499:Protein Processing, Post-Translational; D018116:Vesiculovirus / Q000187:drug effects*; D014764:Viral Proteins / Q000096:biosynthesis*; D019892:eIF-2 Kinase / Q000378:metabolism*
chemical_list: D000998:Antiviral Agents; D020536:Enzyme Activators; D015852:Eukaryotic Initiation Factor-2; D014764:Viral Proteins; D019892:eIF-2 Kinase; D007213:Indomethacin