title: Interleukin-12 inhibits liver-specific drug-inducible systems in vivo.
abstract: Drug-inducible systems allow modulation of the duration and intensity of cytokine expression in liver immuno-based gene therapy protocols. However, the biological activity of the transgene may influence their function. We have analyzed the kinetics of interleukin-12 (IL-12) expression controlled by the doxycycline (Dox)- and the mifepristone (Mif)-dependent systems using two long-term expressing vectors directed to liver: a plasmid administered by hydrodynamic injection and a high-capacity adenoviral vector. Daily administration of Dox or Mif was associated with a progressive loss of inducibility and a decrease of murine IL-12 production. This inhibition occurred at the transcriptional level and was probably caused by an interferon (IFN)-gamma-mediated downmodulation of liver-specific promoters that control the expression of transactivators in these systems. Genome-wide expression microarrays studies revealed a parallel downregulation of liver-specific genes in mice overexpressing murine IL-12. However, a promoter naturally induced by IL-12 was also inhibited by this cytokine when placed in a plasmid vector. Interestingly, treatment with sodium butyrate, a class I/II histone deacetylase inhibitor, was able to rescue liver-specific promoter activity solely in the vector. We conclude that biologically active IL-12 can transiently inhibit the function of drug-inducible systems in non-integrative DNA vectors by reducing promoter activity, probably through IFN-gamma and protein deacetylation-dependent mechanisms.
authors.affiliation: Division of Hepatology and Gene Therapy, School of Medicine, Foundation for Applied Medical Research, University of Navarra, Pamplona, Navarra, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Reboredo
authors.forename: M
authors.initials: M
authors.lastname: Zabala
authors.forename: I
authors.initials: I
authors.lastname: Mauleon
authors.forename: J
authors.initials: J
authors.lastname: De Las Rivas
authors.forename: F
authors.initials: F
authors.lastname: Kreppel
authors.forename: S
authors.initials: S
authors.lastname: Kochanek
authors.forename: J
authors.initials: J
authors.lastname: Prieto
authors.forename: R
authors.initials: R
authors.lastname: Hernandez-Alcoceba
authors.forename: M G
authors.initials: MG
authors.lastname: Kramer
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D002087:Butyrates / Q000494:pharmacology; D015536:Down-Regulation; D004318:Doxycycline / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression; D020868:Gene Silencing; D005822:Genetic Vectors; D056572:Histone Deacetylase Inhibitors; D007371:Interferon-gamma / Q000096:biosynthesis / Q000502:physiology; D018664:Interleukin-12 / Q000235:genetics*; D008099:Liver / Q000187:drug effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D015735:Mifepristone / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D002087:Butyrates; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D012333:RNA, Messenger; D018664:Interleukin-12; D015735:Mifepristone; D007371:Interferon-gamma; D004318:Doxycycline