Regulation of CXCL-8 (interleukin-8) induction by double-stranded RNA signaling pathways during hepatitis C virus infection.
Hepatitis C virus (HCV) infection induces the alpha-chemokine interleukin-8 (CXCL-8), which is regulated at the levels of transcription and mRNA stability. In the current study, CXCL-8 regulation by double-stranded (ds)RNA pathways was analyzed in the context of HCV infection. A constitutively active mutant of the retinoic acid-inducible gene I (RIG-I), RIG-N, activated CXCL-8 transcription. Promoter mutagenesis experiments indicated that NF-kappaB and interferon (IFN)-stimulated response element (ISRE) binding sites were required for the RIG-N induction of CXCL-8 transcription. IFN-beta promoter stimulator 1 (IPS-1) expression also activated CXCL-8 transcription, and mutations of the ISRE and NF-kappaB binding sites reduced and abrogated CXCL-8 transcription, respectively. In the presence of wild-type RIG-I, transfection of JFH-1 RNA or JFH-1 virus infection of Huh7.5.1 cells activated the CXCL-8 promoter. Expression of IFN regulatory factor 3 (IRF-3) stimulated transcription from both full-length and ISRE-driven CXCL-8 promoters. Chromatin immunoprecipitation assays demonstrated that IRF-3 and NF-kappaB bound directly to the CXCL-8 promoter in response to virus infection and dsRNA transfection. RIG-N stabilized CXCL-8 mRNA via the AU-rich element in the 3' untranslated region of CXCL-8 mRNA, leading to an increase in its half-life following tumor necrosis factor alpha induction. The data indicate that HCV infection triggers dsRNA signaling pathways that induce CXCL-8 via transcriptional activation and mRNA stabilization and define a regulatory link between innate antiviral and inflammatory cellular responses to virus infection.
Wagoner
Jessica
J
Department of Laboratory Medicine, University of Washington, Virology 359690, 325 9th Avenue, Seattle, WA 98104-2499, USA.
Austin
Michael
M
Green
Jamison
J
Imaizumi
Tadaatsu
T
Casola
Antonella
A
Brasier
Allan
A
Khabar
Khalid S A
KS
Wakita
Takaji
T
Gale
Michael
M
Polyak
Stephen J
SJ
D002460:Cell Line; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D016174:Hepacivirus / Q000276:immunology*; D006801:Humans; D050838:Interferon Regulatory Factor-3 / Q000378:metabolism / Q000502:physiology; D016209:Interleukin-8 / Q000096:biosynthesis / Q000235:genetics*; D009154:Mutation; D011401:Promoter Regions, Genetic; D012330:RNA, Double-Stranded / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011971:Receptors, Immunologic; D015398:Signal Transduction; D014158:Transcription, Genetic
D050838:Interferon Regulatory Factor-3; D016209:Interleukin-8; D012330:RNA, Double-Stranded; D012333:RNA, Messenger; D011971:Receptors, Immunologic; C452820:RIGI protein, human; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases