title: Residue 82 of the Chikungunya virus E2 attachment protein modulates viral dissemination and arthritis in mice.
abstract: Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that has reemerged to cause profound epidemics of fever, rash, and arthralgia throughout sub-Saharan Africa, Southeast Asia, and the Caribbean. Like other arthritogenic alphaviruses, mechanisms of CHIKV pathogenesis are not well defined. Using the attenuated CHIKV strain 181/25 and virulent strain AF15561, we identified a residue in the E2 viral attachment protein that is a critical determinant of viral replication in cultured cells and pathogenesis in vivo. Viruses containing an arginine at E2 residue 82 displayed enhanced infectivity in mammalian cells but reduced infectivity in mosquito cells and diminished virulence in a mouse model of CHIKV disease. Mice inoculated with virus containing an arginine at this position exhibited reduced swelling at the site of inoculation with a concomitant decrease in the severity of necrosis in joint-associated tissues. Viruses containing a glycine at E2 residue 82 produced higher titers in the spleen and serum at early times postinfection. Using wild-type and glycosaminoglycan (GAG)-deficient Chinese hamster ovary (CHO) cell lines and soluble GAGs, we found that an arginine at residue 82 conferred greater dependence on GAGs for infection of mammalian cells. These data suggest that CHIKV E2 interactions with GAGs diminish dissemination to lymphoid tissue, establishment of viremia, and activation of inflammatory responses early in infection. Collectively, these results suggest a function for GAG utilization in regulating CHIKV tropism and host responses that contribute to arthritis.
  
  
  OBJECTIVE
  CHIKV is a reemerging alphavirus of global significance with high potential to spread into new, immunologically naive populations. The severity of CHIKV disease, particularly its propensity for chronic musculoskeletal manifestations, emphasizes the need for identification of genetic determinants that dictate CHIKV virulence in the host. To better understand mechanisms of CHIKV pathogenesis, we probed the function of an amino acid polymorphism in the E2 viral attachment protein using a mouse model of CHIKV musculoskeletal disease. In addition to influencing glycosaminoglycan utilization, we identified roles for this polymorphism in differential infection of mammalian and mosquito cells and targeting of CHIKV to specific tissues within infected mice. These studies demonstrate a correlation between CHIKV tissue tropism and virus-induced pathology modulated by a single polymorphism in E2, which in turn illuminates potential targets for vaccine and antiviral drug development.
authors.affiliation: Departments of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA Elizabeth B. Lamb Center for Pediatric Research, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
authors.forename: Alison W
authors.initials: AW
authors.lastname: Ashbrook
authors.affiliation: Department of Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA.
authors.forename: Kristina S
authors.initials: KS
authors.lastname: Burrack
authors.affiliation: Elizabeth B. Lamb Center for Pediatric Research, Vanderbilt University School of Medicine, Nashville, Tennessee, USA Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
authors.forename: Laurie A
authors.initials: LA
authors.lastname: Silva
authors.affiliation: Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Montgomery
authors.affiliation: Departments of Genetics and of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
authors.forename: Mark T
authors.initials: MT
authors.lastname: Heise
authors.affiliation: Department of Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Morrison
authors.affiliation: Departments of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA Elizabeth B. Lamb Center for Pediatric Research, Vanderbilt University School of Medicine, Nashville, Tennessee, USA Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA terry.dermody@vanderbilt.edu.
authors.forename: Terence S
authors.initials: TS
authors.lastname: Dermody
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001168:Arthritis / Q000473:pathology / Q000821:virology*; D016466:CHO Cells; D002646:Chikungunya virus / Q000472:pathogenicity / Q000502:physiology*; D003412:Cricetulus; D004195:Disease Models, Animal; D008810:Mice, Inbred C57BL; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism*; D056189:Viral Tropism; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D050505:Mutant Proteins; D014759:Viral Envelope Proteins; D037521:Virulence Factors