title: Convallatoxin-Induced Reduction of Methionine Import Effectively Inhibits Human Cytomegalovirus Infection and Replication.
abstract: Cytomegalovirus (CMV) is a ubiquitous human pathogen that increases the morbidity and mortality of immunocompromised individuals. The current FDA-approved treatments for CMV infection are intended to be virus specific, yet they have significant adverse side effects, including nephrotoxicity and hematological toxicity. Thus, there is a medical need for safer and more effective CMV therapeutics. Using a high-content screen, we identified the cardiac glycoside convallatoxin as an effective compound that inhibits CMV infection. Using a panel of cardiac glycoside variants, we assessed the structural elements critical for anti-CMV activity by both experimental and in silico methods. Analysis of the antiviral effects, toxicities, and pharmacodynamics of different variants of cardiac glycosides identified the mechanism of inhibition as reduction of methionine import, leading to decreased immediate-early gene translation without significant toxicity. Also, convallatoxin was found to dramatically reduce the proliferation of clinical CMV strains, implying that its mechanism of action is an effective strategy to block CMV dissemination. Our study has uncovered the mechanism and structural elements of convallatoxin, which are important for effectively inhibiting CMV infection by targeting the expression of immediate-early genes.
  
  
  OBJECTIVE
  Cytomegalovirus is a highly prevalent virus capable of causing severe disease in certain populations. The current FDA-approved therapeutics all target the same stage of the viral life cycle and induce toxicity and viral resistance. We identified convallatoxin, a novel cell-targeting antiviral that inhibits CMV infection by decreasing the synthesis of viral proteins. At doses low enough for cells to tolerate, convallatoxin was able to inhibit primary isolates of CMV, including those resistant to the anti-CMV drug ganciclovir. In addition to identifying convallatoxin as a novel antiviral, limiting mRNA translation has a dramatic impact on CMV infection and proliferation.
authors.affiliation: Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Tobias
authors.initials: T
authors.lastname: Cohen
authors.affiliation: Microbiotix Inc. Worcester, Massachusetts, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Williams
authors.affiliation: Microbiotix Inc. Worcester, Massachusetts, USA.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Opperman
authors.affiliation: Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.|Experimental Therapeutics Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Roberto
authors.initials: R
authors.lastname: Sanchez
authors.affiliation: Department of Immunology-Microbiology, Rush University, Chicago, Illinois, USA.
authors.forename: Nell S
authors.initials: NS
authors.lastname: Lurain
authors.affiliation: Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA domenico.tortorella@mssm.edu.
authors.forename: Domenico
authors.initials: D
authors.lastname: Tortorella
mesh_terms: D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology*; D001693:Biological Transport, Active / Q000187:drug effects; D002301:Cardiac Glycosides / Q000737:chemistry / Q000494:pharmacology; D002460:Cell Line; D003587:Cytomegalovirus / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D003586:Cytomegalovirus Infections / Q000378:metabolism / Q000517:prevention & control* / Q000821:virology; D017781:Genes, Immediate-Early / Q000187:drug effects; D005814:Genes, Viral / Q000187:drug effects; D006801:Humans; D008715:Methionine / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D015394:Molecular Structure; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D013328:Strophanthins / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D002301:Cardiac Glycosides; D012333:RNA, Messenger; D012367:RNA, Viral; D013328:Strophanthins; D008715:Methionine; C000505:convallatoxin