title: C5aR, TNF-α, and FGL2 contribute to coagulation and complement activation in virus-induced fulminant hepatitis.
abstract: OBJECTIVE
  Viral fulminant hepatitis (FH) is a disease with a high mortality rate. Activation of the complement system correlates with the development of FH. However, the key factors mediating complement activation in FH remain elusive.
  
  
  METHODS
  Liver tissues were isolated from FH patients infected by hepatitis B virus (HBV) and from mice infected with murine hepatitis virus strain 3 (MHV-3). Wild type mice were treated with or without antagonists of C5aR or TNF-α, and mice deficient for C5aR (C5aR(-/-)), Fgl2 (Fgl2(-/-)), and Tnfα (Tnfα(-/-)) mice were not treated with the antagonists. C5b-9, C5aR, FGL2, CD31, CD11b, fibrin, TNF-α, and complement C3 cleavage products were detected by immunohistochemistry, immunofluorescence, or ELISA. Sorted liver sinusoidal endothelial cells (LSECs) or myeloid-derived (CD11b(+)) cells were stimulated with C5a, TNF-α or MHV-3 in vitro. The mRNA expressions levels of Fgl2 and Tnfα were determined by qRT-PCR analyses.
  
  
  RESULTS
  We observed that complement activation, coagulation and pro-inflammatory cytokine production were upregulated in the HBV(+) patients with FH. Similar observations were made in the murine FH models. Complement activation and coagulation were significantly reduced in MHV-3 infected mice in the absence of C5aR, Tnfα or Fgl2. The MHV-3 infected C5aR(-/-) mice exhibited reduced numbers of infiltrated inflammatory CD11b(+) cells and a reduced expression of TNF-α and FGL2. Moreover, C5a administration stimulated TNF-α production by CD11b(+) cells, which in turn promoted the expression of FGL2 in CD31(+) LSEC-like cells in vitro. Administration of antagonists against C5aR or TNF-α ameliorated MHV-3-induced FH.
  
  
  CONCLUSIONS
  Our results demonstrate that C5aR, TNF-α, and FGL2 form an integral network that contributes to coagulation and complement activation, and suggest that those are potential therapeutic targets in viral FH intervention.
authors.affiliation: Institute of Cancer, Xinqiao Hospital, Third Military Medical University, Chongqing, China; Department of Histology & Embryology, Third Military Medical University, Chongqing, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Immunology, Third Military Medical University, Chongqing, China.
authors.forename: Yulong
authors.initials: Y
authors.lastname: Tan
authors.affiliation: Department of Immunology, Third Military Medical University, Chongqing, China.
authors.forename: Jinyu
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Immunology, Third Military Medical University, Chongqing, China.
authors.forename: Liyun
authors.initials: L
authors.lastname: Zou
authors.affiliation: Institute of Infectious Diseases, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Guohong
authors.initials: G
authors.lastname: Deng
authors.affiliation: Department of Medical Genetics, Third Military Medical University, Chongqing, China.
authors.forename: Xueqing
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Laboratory Medicine, Daping Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Institute of Hepatobiliary Surgery & Southwest Hospital, Third Military Medical University, District Shapingba, Chongqing, China.
authors.forename: Zhengwei
authors.initials: Z
authors.lastname: Ma
authors.affiliation: Institute of Cancer, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Jue
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Immunology, Third Military Medical University, Chongqing, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Zhao
authors.affiliation: Department of Histology & Embryology, Third Military Medical University, Chongqing, China.
authors.forename: Yunlai
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Institute of Cancer, Xinqiao Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Cancer, Xinqiao Hospital, Third Military Medical University, Chongqing, China. Electronic address: b.davis.zhu@gmail.com.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhu
authors.affiliation: Institute of Cancer, Xinqiao Hospital, Third Military Medical University, Chongqing, China; Department of Immunology, Third Military Medical University, Chongqing, China. Electronic address: guobomail@gmail.com.
authors.forename: Bo
authors.initials: B
authors.lastname: Guo
mesh_terms: D000818:Animals; D001777:Blood Coagulation / Q000235:genetics*; D003167:Complement Activation / Q000235:genetics*; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005340:Fibrinogen / Q000096:biosynthesis / Q000235:genetics*; D005786:Gene Expression Regulation; D006524:Hepatitis, Viral, Animal / Q000378:metabolism* / Q000473:pathology / Q000821:virology; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D006517:Murine hepatitis virus / Q000472:pathogenicity; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D044087:Receptor, Anaphylatoxin C5a / Q000096:biosynthesis / Q000235:genetics*; D013601:T-Lymphocytes; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics*
chemical_list: C000591759:C5ar1 protein, mouse; C490637:Fgl2 protein, mouse; D012333:RNA, Messenger; D044087:Receptor, Anaphylatoxin C5a; D014409:Tumor Necrosis Factor-alpha; D005340:Fibrinogen
keywords: C5a/C5aR; Complement; Fibrinogen-like protein 2 (FGL2)/fibroleukin; Fulminant hepatitis