title: RNA-Seq analysis of chikungunya virus infection and identification of granzyme A as a major promoter of arthritic inflammation.
abstract: Chikungunya virus (CHIKV) is an arthritogenic alphavirus causing epidemics of acute and chronic arthritic disease. Herein we describe a comprehensive RNA-Seq analysis of feet and lymph nodes at peak viraemia (day 2 post infection), acute arthritis (day 7) and chronic disease (day 30) in the CHIKV adult wild-type mouse model. Genes previously shown to be up-regulated in CHIKV patients were also up-regulated in the mouse model. CHIKV sequence information was also obtained with up to ≈8% of the reads mapping to the viral genome; however, no adaptive viral genome changes were apparent. Although day 2, 7 and 30 represent distinct stages of infection and disease, there was a pronounced overlap in up-regulated host genes and pathways. Type I interferon response genes (IRGs) represented up to ≈50% of up-regulated genes, even after loss of type I interferon induction on days 7 and 30. Bioinformatic analyses suggested a number of interferon response factors were primarily responsible for maintaining type I IRG induction. A group of genes prominent in the RNA-Seq analysis and hitherto unexplored in viral arthropathies were granzymes A, B and K. Granzyme A-/- and to a lesser extent granzyme K-/-, but not granzyme B-/-, mice showed a pronounced reduction in foot swelling and arthritis, with analysis of granzyme A-/- mice showing no reductions in viral loads but reduced NK and T cell infiltrates post CHIKV infection. Treatment with Serpinb6b, a granzyme A inhibitor, also reduced arthritic inflammation in wild-type mice. In non-human primates circulating granzyme A levels were elevated after CHIKV infection, with the increase correlating with viral load. Elevated granzyme A levels were also seen in a small cohort of human CHIKV patients. Taken together these results suggest granzyme A is an important driver of arthritic inflammation and a potential target for therapy.
  
  
  
  ClinicalTrials.gov NCT00281294.
authors.affiliation: QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.|Australian Infectious Disease Research Centre, The University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Jane A C
authors.initials: JA
authors.lastname: Wilson
authors.affiliation: QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
authors.forename: Natalie A
authors.initials: NA
authors.lastname: Prow
authors.affiliation: QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
authors.forename: Wayne A
authors.initials: WA
authors.lastname: Schroder
authors.affiliation: QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Ellis
authors.affiliation: Hudson Institute of Medical Research, Clayton, Victoria, Australia.
authors.forename: Helen E
authors.initials: HE
authors.lastname: Cumming
authors.affiliation: Hudson Institute of Medical Research, Clayton, Victoria, Australia.
authors.forename: Linden J
authors.identifier: 0000-0003-3508-3056
authors.initials: LJ
authors.lastname: Gearing
authors.affiliation: QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.|Australian Infectious Disease Research Centre, The University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Yee Suan
authors.initials: YS
authors.lastname: Poo
authors.affiliation: Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia.
authors.forename: Adam
authors.identifier: 0000-0002-7159-3961
authors.initials: A
authors.lastname: Taylor
authors.affiliation: Hudson Institute of Medical Research, Clayton, Victoria, Australia.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Hertzog
authors.affiliation: Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Francesca
authors.initials: F
authors.lastname: Di Giallonardo
authors.affiliation: Centre for Infectious Diseases and Microbiology Laboratory Services, Westmead Hospital, Sydney, NSW, Australia.
authors.forename: Linda
authors.initials: L
authors.lastname: Hueston
authors.affiliation: CEA, Inserm, Université Paris Sud; iMETI; UMR 1184 Immunology of Viral infections and Autoimmune diseases, Fontenay-aux-Roses, France.
authors.forename: Roger
authors.initials: R
authors.lastname: Le Grand
authors.affiliation: QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
authors.forename: Bing
authors.initials: B
authors.lastname: Tang
authors.affiliation: QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
authors.forename: Thuy T
authors.identifier: 0000-0001-9134-0104
authors.initials: TT
authors.lastname: Le
authors.affiliation: QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
authors.forename: Joy
authors.initials: J
authors.lastname: Gardner
authors.affiliation: Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia.
authors.forename: Suresh
authors.initials: S
authors.lastname: Mahalingam
authors.affiliation: CEA, Inserm, Université Paris Sud; iMETI; UMR 1184 Immunology of Viral infections and Autoimmune diseases, Fontenay-aux-Roses, France.
authors.forename: Pierre
authors.identifier: 0000-0003-1825-1054
authors.initials: P
authors.lastname: Roques
authors.affiliation: Biomedicine Discovery Institute, Monash University, Victoria 3800, Australia.
authors.forename: Phillip I
authors.initials: PI
authors.lastname: Bird
authors.affiliation: QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.|Australian Infectious Disease Research Centre, The University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Andreas
authors.identifier: 0000-0001-8986-9025
authors.initials: A
authors.lastname: Suhrbier
mesh_terms: D000818:Animals; D001168:Arthritis / Q000821:virology*; D065632:Chikungunya Fever / Q000235:genetics* / Q000276:immunology*; D002646:Chikungunya virus; D004195:Disease Models, Animal; D053804:Granzymes / Q000032:analysis / Q000096:biosynthesis / Q000276:immunology*; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000821:virology*; D008252:Macaca fascicularis; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D012333:RNA, Messenger / Q000032:analysis; D059467:Transcriptome
chemical_list: D012333:RNA, Messenger; D053804:Granzymes