title: Heat Shock Protein 70 Family Members Interact with Crimean-Congo Hemorrhagic Fever Virus and Hazara Virus Nucleocapsid Proteins and Perform a Functional Role in the Nairovirus Replication Cycle.
abstract: The Nairovirus genus of the Bunyaviridae family contains serious human and animal pathogens classified within multiple serogroups and species. Of these serogroups, the Crimean-Congo hemorrhagic fever virus (CCHFV) serogroup comprises sole members CCHFV and Hazara virus (HAZV). CCHFV is an emerging zoonotic virus that causes often-fatal hemorrhagic fever in infected humans for which preventative or therapeutic strategies are not available. In contrast, HAZV is nonpathogenic to humans and thus represents an excellent model to study aspects of CCHFV biology under conditions of more-accessible biological containment. The three RNA segments that form the nairovirus genome are encapsidated by the viral nucleocapsid protein (N) to form ribonucleoprotein (RNP) complexes that are substrates for RNA synthesis and packaging into virus particles. We used quantitative proteomics to identify cellular interaction partners of CCHFV N and identified robust interactions with cellular chaperones. These interactions were validated using immunological methods, and the specific interaction between native CCHFV N and cellular chaperones of the HSP70 family was confirmed during live CCHFV infection. Using infectious HAZV, we showed for the first time that the nairovirus N-HSP70 association was maintained within both infected cells and virus particles, where N is assembled as RNPs. Reduction of active HSP70 levels in cells by the use of small-molecule inhibitors significantly reduced HAZV titers, and a model for chaperone function in the context of high genetic variability is proposed. These results suggest that chaperones of the HSP70 family are required for nairovirus replication and thus represent a genetically stable cellular therapeutic target for preventing nairovirus-mediated disease.
  
  
  
  Nairoviruses compose a group of human and animal viruses that are transmitted by ticks and associated with serious or fatal disease. One member is Crimean-Congo hemorrhagic fever virus (CCHFV), which is responsible for fatal human disease and is recognized as an emerging threat within Europe in response to climate change. No preventative or therapeutic strategies against nairovirus-mediated disease are currently available. Here we show that the N protein of CCHFV and the related Hazara virus interact with a cellular protein, HSP70, during both the intracellular and extracellular stages of the virus life cycle. The use of inhibitors that block HSP70 function reduces virus titers by up to 1,000-fold, suggesting that this interaction is important within the context of the nairovirus life cycle and may represent a potent target for antinairovirus therapies against which the virus cannot easily develop resistance.
authors: Virology & Pathogenesis, Public Health England, Porton Down, Salisbury, United Kingdom School of Molecular and Cellular Biology, Faculty of Biological Sciences, and Astbury Centre for Molecular and Structural Biology, University of Leeds, Leeds, United Kingdom.
authors: Rebecca
authors: R
authors: Surtees
authors: Virology & Pathogenesis, Public Health England, Porton Down, Salisbury, United Kingdom NIHR Health Protection Research Unit in Emerging and Zoonotic Infection, Liverpool, United Kingdom.
authors: Stuart D
authors: SD
authors: Dowall
authors: School of Molecular and Cellular Biology, Faculty of Biological Sciences, and Astbury Centre for Molecular and Structural Biology, University of Leeds, Leeds, United Kingdom.
authors: Amelia
authors: A
authors: Shaw
authors: Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom NIHR Health Protection Research Unit in Emerging and Zoonotic Infection, Liverpool, United Kingdom.
authors: Stuart
authors: S
authors: Armstrong
authors: Virology & Pathogenesis, Public Health England, Porton Down, Salisbury, United Kingdom NIHR Health Protection Research Unit in Emerging and Zoonotic Infection, Liverpool, United Kingdom.
authors: Roger
authors: R
authors: Hewson
authors: Virology & Pathogenesis, Public Health England, Porton Down, Salisbury, United Kingdom NIHR Health Protection Research Unit in Emerging and Zoonotic Infection, Liverpool, United Kingdom.
authors: Miles W
authors: MW
authors: Carroll
authors: School of Molecular and Cellular Biology, Faculty of Biological Sciences, and Astbury Centre for Molecular and Structural Biology, University of Leeds, Leeds, United Kingdom.
authors: Jamel
authors: J
authors: Mankouri
authors: School of Molecular and Cellular Biology, Faculty of Biological Sciences, and Astbury Centre for Molecular and Structural Biology, University of Leeds, Leeds, United Kingdom.
authors: Thomas A
authors: TA
authors: Edwards
authors: Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom NIHR Health Protection Research Unit in Emerging and Zoonotic Infection, Liverpool, United Kingdom julian.hiscox@liverpool.ac.uk j.n.barr@leeds.ac.uk.
authors: Julian A
authors: JA
authors: Hiscox
authors: School of Molecular and Cellular Biology, Faculty of Biological Sciences, and Astbury Centre for Molecular and Structural Biology, University of Leeds, Leeds, United Kingdom julian.hiscox@liverpool.ac.uk j.n.barr@leeds.ac.uk.
authors: John N
authors: JN
authors: Barr
mesh_terms: D000072283:A549 Cells; D002460:Cell Line; D045744:Cell Line, Tumor; D057231:Climate Change; D005060:Europe; D057809:HEK293 Cells; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D003225:Hemorrhagic Fever Virus, Crimean-Congo / Q000235:genetics* / Q000378:metabolism*; D006479:Hemorrhagic Fever, Crimean / Q000378:metabolism / Q000821:virology; D006801:Humans; D016855:Nairovirus / Q000235:genetics* / Q000378:metabolism*; D019590:Nucleocapsid Proteins / Q000378:metabolism*; D012313:RNA / Q000235:genetics; D014779:Virus Replication / Q000235:genetics*
chemical_list: D018840:HSP70 Heat-Shock Proteins; D019590:Nucleocapsid Proteins; D012313:RNA