title: JUNB/AP-1 controls IFN-γ during inflammatory liver disease.
abstract: Understanding the molecular pathogenesis of inflammatory liver disease is essential to design efficient therapeutic approaches. In hepatocytes, the dimeric transcription factor c-JUN/AP-1 is a major mediator of cell survival during hepatitis, although functions for other JUN proteins in liver disease are less defined. Here, we found that JUNB was specifically expressed in human and murine immune cells during acute liver injury. We analyzed the molecular function of JUNB in experimental models of hepatitis, including administration of concanavalin A (ConA) or α-galactosyl-ceramide, which induce liver inflammation and injury. Mice specifically lacking JUNB in hepatocytes displayed a mild increase in ConA-induced liver damage. However, targeted deletion of Junb in immune cells and hepatocytes protected against hepatitis in experimental models that involved NK/NKT cells. The absence of JUNB in immune cells decreased IFN-γ expression and secretion from NK and NKT cells, leading to reduced STAT1 pathway activation. Systemic IFN-γ treatment or adenovirus-based IRF1 delivery to Junb-deficient mice restored hepatotoxicity, and we demonstrate that Ifng is a direct transcriptional target of JUNB. These findings demonstrate that JUNB/AP-1 promotes cell death during acute hepatitis by regulating IFN-γ production in NK and NKT cells and thus functionally antagonizes the hepatoprotective function of c-JUN/AP-1 in hepatocytes.
authors.forename: Martin K
authors.initials: MK
authors.lastname: Thomsen
authors.forename: Latifa
authors.initials: L
authors.lastname: Bakiri
authors.forename: Sebastian C
authors.initials: SC
authors.lastname: Hasenfuss
authors.forename: Rainer
authors.initials: R
authors.lastname: Hamacher
authors.forename: Lola
authors.initials: L
authors.lastname: Martinez
authors.forename: Erwin F
authors.initials: EF
authors.lastname: Wagner
mesh_terms: D000818:Animals; D016923:Cell Death; D056486:Chemical and Drug Induced Liver Injury / Q000209:etiology / Q000276:immunology / Q000378:metabolism; D003208:Concanavalin A / Q000633:toxicity; D005699:Galactosylceramides / Q000633:toxicity; D006505:Hepatitis / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D050856:Interferon Regulatory Factor-1 / Q000502:physiology; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D055611:Natural Killer T-Cells / Q000378:metabolism*; D011070:Poly I-C / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D050794:STAT1 Transcription Factor / Q000378:metabolism; D014157:Transcription Factors / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic; D014161:Transduction, Genetic
chemical_list: D005699:Galactosylceramides; C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; C581727:JunB protein, human; C584097:JunB protein, mouse; D011993:Recombinant Fusion Proteins; D050794:STAT1 Transcription Factor; C494080:Stat1 protein, mouse; D014157:Transcription Factors; C493154:alpha-galactosylceramide; D003208:Concanavalin A; D007371:Interferon-gamma; D011070:Poly I-C