title: Vaccinia virus induces rapid necrosis in keratinocytes by a STAT3-dependent mechanism.
abstract: BACKGROUND
  Humans with a dominant negative mutation in STAT3 are susceptible to severe skin infections, suggesting an essential role for STAT3 signaling in defense against cutaneous pathogens.
  
  
  METHODS
  To focus on innate antiviral defenses in keratinocytes, we used a standard model of cutaneous infection of severe combined immunodeficient mice with the current smallpox vaccine, ACAM-2000. In parallel, early events post-infection with the smallpox vaccine ACAM-2000 were investigated in cultured keratinocytes of human and mouse origin.
  
  
  RESULTS
  Mice treated topically with a STAT3 inhibitor (Stattic) developed larger vaccinia lesions with higher virus titers and died more rapidly than untreated controls. Cultured human and murine keratinocytes infected with ACAM-2000 underwent rapid necrosis, but when treated with Stattic or with inhibitors of RIP1 kinase or caspase-1, they survived longer, produced higher titers of virus, and showed reduced activation of type I interferon responses and inflammatory cytokines release. Treatment with inhibitors of RIP1 kinase and STAT3, but not caspase-1, also reduced the inflammatory response of keratinocytes to TLR ligands. Vaccinia growth properties in Vero cells, which are known to be defective in some antiviral responses, were unaffected by inhibition of RIP1K, caspase-1, or STAT3.
  
  
  CONCLUSIONS
  Our findings indicate that keratinocytes suppress the replication and spread of vaccinia virus by undergoing rapid programmed cell death, in a process requiring STAT3. These data offer a new framework for understanding susceptibility to skin infection in patients with STAT3 mutations. Interventions which promote prompt necroptosis/pyroptosis of infected keratinocytes may reduce risks associated with vaccination with live vaccinia virus.
authors.affiliation: Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America.
authors.forename: Yong
authors.initials: Y
authors.lastname: He
authors.affiliation: Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America.
authors.forename: Robert
authors.initials: R
authors.lastname: Fisher
authors.affiliation: Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America.
authors.forename: Soma
authors.initials: S
authors.lastname: Chowdhury
authors.affiliation: Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America.
authors.forename: Ishrat
authors.initials: I
authors.lastname: Sultana
authors.affiliation: Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America.
authors.forename: Claudia P
authors.initials: CP
authors.lastname: Pereira
authors.affiliation: Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Mike
authors.initials: M
authors.lastname: Bray
authors.affiliation: Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Reed
mesh_terms: D000818:Animals; D020170:Caspase 1 / Q000276:immunology / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003499:Cyclic S-Oxides / Q000494:pharmacology; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000276:immunology / Q000494:pharmacology; D054884:Host-Pathogen Interactions / Q000187:drug effects / Q000276:immunology; D006801:Humans; D015151:Immunoblotting; D018836:Inflammation Mediators / Q000276:immunology / Q000378:metabolism; D007370:Interferon Type I / Q000276:immunology / Q000378:metabolism; D015603:Keratinocytes / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D016513:Mice, SCID; D009336:Necrosis / Q000276:immunology; D034622:RNA Interference / Q000276:immunology; D053422:Receptor-Interacting Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000037:antagonists & inhibitors / Q000276:immunology* / Q000378:metabolism; D012900:Smallpox Vaccine / Q000276:immunology / Q000494:pharmacology; D014615:Vaccinia / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D014616:Vaccinia virus / Q000276:immunology* / Q000502:physiology; D014709:Vero Cells
chemical_list: C000588544:ACAM2000; D003499:Cyclic S-Oxides; D016207:Cytokines; D004791:Enzyme Inhibitors; D018836:Inflammation Mediators; D007370:Interferon Type I; D050796:STAT3 Transcription Factor; D012900:Smallpox Vaccine; C517409:stattic; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; D020170:Caspase 1