title: Identification of proteins that mediate the pro-viral functions of the interferon stimulated gene 15 in hepatitis C virus replication.
abstract: In previous studies we identified the interferon stimulated gene 15 (ISG15) as a pro-viral host factor in the pathogenesis of hepatitis C virus (HCV) infection. However, the functional link between ISG15 and the HCV replication cycle is not well understood. Aim of the present study was to functionally analyze the role of ISG15 and to identify possible HCV promoting effector molecules. Isg15 suppression was investigated in the murine subgenomic HCV replicon (MH1) transfected with Isg15-specific siRNA and in C57BL/6 mice intravenously injected with lipid nanoparticles (LNP)-formulated siRNA. Interestingly, the LNP-formulated siRNA led to hepatocyte-specific knockdown of Isg15 in vivo, which mediated a hypo-responsiveness to endogenous and exogenous interferon. A label free proteome analysis accompanied by western blot and quantitative RT-PCR techniques led to identification of five candidate proteins (Heterogeneous nuclear ribonucleoprotein A3 (HnrnpA3), Heterogeneous nuclear ribonucleoprotein K (HnrnpK), Hydroxymethylglutaryl-CoA synthase (Hmgcs1), Isocitrate dehydrogenase cytoplasmic (Idh1) and Thioredoxin domain-containing protein 5 (Txndc5)) that are either involved in lipid metabolism or belong to the family of Heterogeneous nuclear ribonucleoprotein (Hnrnp). All candidate proteins are likely to be associated with the HCV replication complex. Furthermore treatment with HnrnpK-specific siRNA directly suppressed HCV replication in vitro. Taken together these data suggest that targeting Isg15 may represent an attractive novel therapeutic option for the treatment of chronic HCV infection.
authors.forename: Catherine I
authors.initials: CI
authors.lastname: Real
authors.forename: Dominik A
authors.initials: DA
authors.lastname: Megger
authors.forename: Barbara
authors.initials: B
authors.lastname: Sitek
authors.forename: Kerstin
authors.initials: K
authors.lastname: Jahn-Hofmann
authors.forename: Ludger M
authors.initials: LM
authors.lastname: Ickenstein
authors.forename: Matthias J
authors.initials: MJ
authors.lastname: John
authors.forename: Andreas
authors.initials: A
authors.lastname: Walker
authors.forename: Joerg
authors.initials: J
authors.lastname: Timm
authors.forename: Katja
authors.initials: K
authors.lastname: Kuhlmann
authors.forename: Martin
authors.initials: M
authors.lastname: Eisenacher
authors.forename: Helmut E
authors.initials: HE
authors.lastname: Meyer
authors.forename: Guido
authors.initials: G
authors.lastname: Gerken
authors.forename: Ruth
authors.initials: R
authors.lastname: Broering
authors.forename: Joerg F
authors.initials: JF
authors.lastname: Schlaak
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D016207:Cytokines / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D016174:Hepacivirus / Q000502:physiology*; D022781:Hepatocytes / Q000378:metabolism / Q000821:virology; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000502:physiology; D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D006904:Hydroxymethylglutaryl-CoA Synthase / Q000502:physiology; D007521:Isocitrate Dehydrogenase / Q000502:physiology; D008114:Liver Neoplasms, Experimental / Q000473:pathology; D046911:Macromolecular Substances; D051379:Mice; D008810:Mice, Inbred C57BL; D053758:Nanoparticles; D020543:Proteome; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D012261:Ribonucleoproteins / Q000502:physiology; D013879:Thioredoxins / Q000502:physiology; D014452:Ubiquitins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology; D014779:Virus Replication / Q000502:physiology*
chemical_list: D016207:Cytokines; C489550:G1p2 protein, mouse; C577277:HNRNPK protein, mouse; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D046911:Macromolecular Substances; C482592:PC-TRP protein, mouse; D020543:Proteome; D034741:RNA, Small Interfering; D012261:Ribonucleoproteins; D014452:Ubiquitins; C502035:hnrnpa3 protein, mouse; D013879:Thioredoxins; D007521:Isocitrate Dehydrogenase; D006904:Hydroxymethylglutaryl-CoA Synthase