title: Verdinexor, a novel selective inhibitor of nuclear export, reduces influenza a virus replication in vitro and in vivo.
abstract: Influenza is a global health concern, causing death, morbidity, and economic losses. Chemotherapeutics that target influenza virus are available; however, rapid emergence of drug-resistant strains is common. Therapeutic targeting of host proteins hijacked by influenza virus to facilitate replication is an antiviral strategy to reduce the development of drug resistance. Nuclear export of influenza virus ribonucleoprotein (vRNP) from infected cells has been shown to be mediated by exportin 1 (XPO1) interaction with viral nuclear export protein tethered to vRNP. RNA interference screening has identified XPO1 as a host proinfluenza factor where XPO1 silencing results in reduced influenza virus replication. The Streptomyces metabolite XPO1 inhibitor leptomycin B (LMB) has been shown to limit influenza virus replication in vitro; however, LMB is toxic in vivo, which makes it unsuitable for therapeutic use. In this study, we tested the anti-influenza virus activity of a new class of orally available small-molecule selective inhibitors of nuclear export, specifically, the XPO1 antagonist KPT-335 (verdinexor). Verdinexor was shown to potently and selectively inhibit vRNP export and effectively inhibited the replication of various influenza virus A and B strains in vitro, including pandemic H1N1 virus, highly pathogenic H5N1 avian influenza virus, and the recently emerged H7N9 strain. In vivo, prophylactic and therapeutic administration of verdinexor protected mice against disease pathology following a challenge with influenza virus A/California/04/09 or A/Philippines/2/82-X79, as well as reduced lung viral loads and proinflammatory cytokine expression, while having minimal toxicity. These studies show that verdinexor acts as a novel anti-influenza virus therapeutic agent.
  
  
  OBJECTIVE
  Antiviral drugs represent important means of influenza virus control. However, substantial resistance to currently approved influenza therapeutic drugs has developed. New antiviral approaches are required to address drug resistance and reduce the burden of influenza virus-related disease. This study addressed critical preclinical studies for the development of verdinexor (KPT-335) as a novel antiviral drug. Verdinexor blocks progeny influenza virus genome nuclear export, thus effectively inhibiting virus replication. Verdinexor was found to limit the replication of various strains of influenza A and B viruses, including a pandemic H1N1 influenza virus strain, a highly pathogenic H5N1 avian influenza virus strain, and a recently emerging H7N9 influenza virus strain. Importantly, oral verdinexor treatments, given prophylactically or therapeutically, were efficacious in limiting lung virus burdens in influenza virus-infected mice, in addition to limiting lung proinflammatory cytokine expression, pathology, and death. Thus, this study demonstrated that verdinexor is efficacious against influenza virus infection in vitro and in vivo.
authors: Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA.
authors: Olivia
authors: O
authors: Perwitasari
authors: Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA.
authors: Scott
authors: S
authors: Johnson
authors: Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA.
authors: Xiuzhen
authors: X
authors: Yan
authors: Department of Pathology, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA.
authors: Elizabeth
authors: E
authors: Howerth
authors: Karyopharm Therapeutics, Inc., Natick, Massachusetts, USA.
authors: Sharon
authors: S
authors: Shacham
authors: Karyopharm Therapeutics, Inc., Natick, Massachusetts, USA.
authors: Yosef
authors: Y
authors: Landesman
authors: Karyopharm Therapeutics, Inc., Natick, Massachusetts, USA.
authors: Erkan
authors: E
authors: Baloglu
authors: Karyopharm Therapeutics, Inc., Natick, Massachusetts, USA.
authors: Dilara
authors: D
authors: McCauley
authors: Karyopharm Therapeutics, Inc., Natick, Massachusetts, USA.
authors: Sharon
authors: S
authors: Tamir
authors: Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA.
authors: S Mark
authors: SM
authors: Tompkins
authors: Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, Georgia, USA ratripp@uga.edu.
authors: Ralph A
authors: RA
authors: Tripp
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000187:drug effects*; D000818:Animals; D000998:Antiviral Agents / Q000378:metabolism* / Q000627:therapeutic use; D002460:Cell Line; D018890:Chemoprevention / Q000379:methods; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000378:metabolism* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D009980:Influenza A virus / Q000187:drug effects / Q000502:physiology*; D009981:Influenza B virus / Q000187:drug effects / Q000502:physiology*; D028884:Karyopherins / Q000037:antagonists & inhibitors*; D008807:Mice, Inbred BALB C; D009976:Orthomyxoviridae Infections / Q000517:prevention & control; D018160:Receptors, Cytoplasmic and Nuclear / Q000037:antagonists & inhibitors*; D014779:Virus Replication / Q000187:drug effects*; D000097606:Exportin 1 Protein
chemical_list: D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D028884:Karyopherins; D018160:Receptors, Cytoplasmic and Nuclear; D000097606:Exportin 1 Protein