Di Matteo Mario, Mátrai Janka, Belay Eyayu, Firdissa Tewodros, Vandendriessche Thierry, Chuah Marinee K L
Division of Gene Therapy & Regenerative Medicine, Free University of Brussels (VUB), University Medical Center - Jette, Brussels, Belgium.
Methods Mol Biol. 2012;859:241-54. doi: 10.1007/978-1-61779-603-6_14.
The PiggyBac (PB) transposon system was originally derived from the cabbage looper moth Trichoplusia ni and represents one of the most promising transposon systems to date. Engineering of the PB transposase enzyme (PBase) and its cognate transposon DNA elements resulted in a substantial increase in transposition activities. Consequently, this has greatly enhanced the versatility of the PB toolbox. It is now widely used for stable gene delivery into a broad variety of cell types from different species, including mammalian cells. This opened up new perspectives for potential therapeutic applications in the fields of gene therapy and regenerative medicine. In particular, we have recently demonstrated that PB transposons could be used to stably deliver genes into human CD34(+) hematopoietic stem cells (HSCs) resulting in sustained transgene expression in its differentiated progeny. The PB transposon system is particularly attractive for the generation of induced pluripotent stem cells (iPS). Typically, this can be accomplished by stable gene transfer of genes encoding one or more reprogramming factors (i.e., c-MYC, KLF-4, OCT-4, and/or SOX-2). We have generated a PB-based nonviral reprogramming toolbox that contains different combinations of these reprogramming genes. The main advantage of using this PB toolbox for iPS generation is that the reprogramming cassette can be excised by de novo transposase expression, without leaving any molecular trace in the target cell genome. This "traceless excision" paradigm obviates potential risks associated with inadvertent re-expression of reprogramming factors in the iPS progeny. These various applications in gene therapy, stem cell engineering, and regenerative medicine underscore the emerging versatility of the PB toolbox.
PiggyBac（PB）转座子系统最初源自甘蓝尺蛾，是迄今为止最有前景的转座子系统之一。对PB转座酶（PBase）及其同源转座子DNA元件进行改造后，转座活性大幅提高。因此，这极大地增强了PB工具箱的多功能性。现在它被广泛用于将基因稳定导入来自不同物种的多种细胞类型，包括哺乳动物细胞。这为基因治疗和再生医学领域的潜在治疗应用开辟了新的前景。特别是，我们最近证明PB转座子可用于将基因稳定导入人CD34(+)造血干细胞（HSCs），从而使其分化后代中持续表达转基因。PB转座子系统对于诱导多能干细胞（iPS）的产生特别有吸引力。通常，这可以通过稳定转染编码一种或多种重编程因子（即c-MYC、KLF-4、OCT-4和/或SOX-2）的基因来实现。我们已经构建了一个基于PB的非病毒重编程工具箱，其中包含这些重编程基因的不同组合。使用这个PB工具箱生成iPS的主要优点是，重编程盒可以通过重新表达转座酶而切除，不会在靶细胞基因组中留下任何分子痕迹。这种“无痕切除”模式避免了与iPS后代中重编程因子意外重新表达相关的潜在风险。这些在基因治疗、干细胞工程和再生医学中的各种应用凸显了PB工具箱日益增长的多功能性。
