Yilmazer Açelya, de Lázaro Irene, Bussy Cyrill, Kostarelos Kostas
Nanomedicine Lab, UCL School of Pharmacy, University College London.
J Vis Exp. 2013 Dec 17(82):e50837. doi: 10.3791/50837.
Induced pluripotent stem (iPS) cells that result from the reprogramming of somatic cells to a pluripotent state by forced expression of defined factors are offering new opportunities for regenerative medicine. Such clinical applications of iPS cells have been limited so far, mainly due to the poor efficiency of the existing reprogramming methodologies and the risk of the generated iPS cells to form tumors upon implantation. We hypothesized that the reprogramming of somatic cells towards pluripotency could be achieved in vivo by gene transfer of reprogramming factors. In order to efficiently reprogram cells in vivo, high levels of the Yamanaka (OKSM) transcription factors need to be expressed at the target tissue. This can be achieved by using different viral or nonviral gene vectors depending on the target tissue. In this particular study, hydrodynamic tail-vein (HTV) injection of plasmid DNA was used to deliver the OKSM factors to mouse hepatocytes. This provided proof-of-evidence of in vivo reprogramming of adult, somatic cells towards a pluripotent state with high efficiency and fast kinetics. Furthermore no tumor or teratoma formation was observed in situ. It can be concluded that reprogramming somatic cells in vivo may offer a potential approach to induce enhanced pluripotency rapidly, efficiently, and safely compared to in vitro performed protocols and can be applied to different tissue types in the future.
通过强制表达特定因子将体细胞重编程为多能状态而产生的诱导多能干细胞（iPS细胞）为再生医学提供了新的机遇。迄今为止，iPS细胞的此类临床应用受到限制，主要是由于现有重编程方法的效率低下以及所产生的iPS细胞在植入后形成肿瘤的风险。我们推测，通过重编程因子的基因转移可在体内实现体细胞向多能性的重编程。为了在体内有效地重编程细胞，需要在靶组织中高水平表达山中（OKSM）转录因子。这可以通过根据靶组织使用不同的病毒或非病毒基因载体来实现。在这项特定研究中，采用水动力尾静脉（HTV）注射质粒DNA将OKSM因子递送至小鼠肝细胞。这提供了成年体细胞在体内高效且快速动力学地重编程为多能状态的证据。此外，原位未观察到肿瘤或畸胎瘤形成。可以得出结论，与体外操作方案相比，体内重编程体细胞可能提供一种快速、高效且安全地诱导增强多能性的潜在方法，并且未来可应用于不同的组织类型。
