Reboredo M, Zabala M, Mauleon I, De Las Rivas J, Kreppel F, Kochanek S, Prieto J, Hernandez-Alcoceba R, Kramer M G
Division of Hepatology and Gene Therapy, School of Medicine, Foundation for Applied Medical Research, University of Navarra, Pamplona, Navarra, Spain.
Gene Ther. 2008 Feb;15(4):277-88. doi: 10.1038/sj.gt.3303073. Epub 2007 Nov 22.
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.
药物诱导系统可在基于肝脏免疫的基因治疗方案中调节细胞因子表达的持续时间和强度。然而，转基因的生物学活性可能会影响其功能。我们使用两种靶向肝脏的长期表达载体（一种通过流体动力学注射给药的质粒和一种高容量腺病毒载体），分析了由强力霉素（Dox）和米非司酮（Mif）依赖性系统控制的白细胞介素-12（IL-12）表达的动力学。每日给予Dox或Mif与诱导性的逐渐丧失以及小鼠IL-12产生的减少有关。这种抑制发生在转录水平，可能是由干扰素（IFN）-γ介导的肝脏特异性启动子下调所致，这些启动子控制着这些系统中反式激活因子的表达。全基因组表达微阵列研究显示，在过表达小鼠IL-12的小鼠中，肝脏特异性基因存在平行下调。然而，当置于质粒载体中时，一种由IL-12天然诱导的启动子也会受到这种细胞因子的抑制。有趣的是，用I/II类组蛋白脱乙酰酶抑制剂丁酸钠处理仅能挽救载体中肝脏特异性启动子的活性。我们得出结论，具有生物学活性的IL-12可能通过降低启动子活性，可能通过IFN-γ和蛋白质脱乙酰化依赖性机制，短暂抑制非整合DNA载体中药物诱导系统的功能。
