The Use of Nonneuronal Cells for Gene Delivery
The Use of Nonneuronal Cells for Gene Delivery
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DOI：
10.1006/nbdi.1997.0138
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发表时间：
1997-12
影响因子：
6.1
通讯作者：
E. Snyder;M. Senut
中科院分区：
文献类型：
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作者：
E. Snyder;M. Senut
基因工程非神经元细胞的植入可以提供用于实现将离散分子局部递送至CNS或用于提供用于神经结构再生长的基质的有效方法。大多数原代非神经元细胞的优点是可以很容易地从预期的宿主中获得，用于体外逆转录病毒介导的遗传操作（大多数在培养中是有丝分裂的）和作为自体移植物再植入（避免免疫排斥的问题）。作为原代细胞，它们不太可能是致瘤性的。这种系统最令人烦恼的问题仍然是在长时间的植入后病毒启动子的转基因表达的明显丧失。目前，许多努力是针对通过改变启动子、通过改变待工程化的细胞类型或通过增强启动子功能或底物可用性来调节表达来优化持续的转基因表达。虽然非神经元细胞是实现物质被动递送至CNS的极好载体，但它们缺乏以功能性方式并入宿主细胞结构的能力（例如，形成突触接触）。由于这个原因，不仅某些基本回路可能无法重建，而且某些物质通过反馈回路的调节释放可能会丢失。虽然对于某些物质（例如，ACh），对于其他（例如，NGF），它们的不受调节的、不适当的、过量的或异位的释放实际上可能对宿主有害。此外，外源基因表达的丧失（基因治疗的祸根）可能使工程化的非神经细胞丧失能力，而来自脑的供体组织可能固有地产生各种CNS因子，从而允许进行校正，尽管引入的基因失活。事实上，CNS衍生的组织可能提供尚未被认识到的内源性神经特异性物质，这些物质与所讨论的基因一样对宿主有益。因此，在某些条件下，基因递送到大脑的未来发展可能强调使用神经元或神经祖细胞进行离体遗传操作（Fisher，1997）和改进用于将治疗基因直接注射到体内神经元中的技术（参见Snyder和Fisher，1996）。然而，对于各种各样的条件下，使用非神经元细胞的车辆，甚至非生物合成车辆可能是有效的，有效的，和安全的策略被动递送治疗分子的离散区域的中枢神经系统。事实上，这种方法可能比其他任何方法都更接近于直接的人类应用。
The implantation of genetically engineered nonneuronal cells can provide an effective method for achieving localized delivery of discrete molecules to the CNS or for providing substrates for regrowth of neural structures. Most primary nonneuronal cells have the advantage of being easily obtainable from the prospective host for ex vivo retrovirus-mediated genetic manipulation (most will be mitotic in culture) and reimplantation as an autologous graft (circumventing the problem of immune rejection). As primary cells, they are unlikely to be tumorigenic. The most vexing problem for such systems remains the apparent loss of transgene expression from viral promoters after prolonged periods of engraftment. Much effort is currently being directed at optimizing sustained transgene expression by varying the promoters, by varying the cell types to be engineered, or by regulating expression by enhancing promoter function or substrate availability. While nonneuronal cells are excellent vehicles for achieving passive delivery of substances to the CNS, they lack the ability to incorporate into the host cytoarchitecture in a functional manner (e.g., make synaptic contacts). For this reason, not only may certain essential circuits not be re-formed, but the regulated release of certain substances through feedback loops may be missing. While apparently unimportant for some substances (e.g., ACh), for others (e.g., NGF), their unregulated, inappropriate, excessive, or ectopic release may actually be inimical to the host. Furthermore, the loss of foreign gene expression (the bane of gene therapy) may leave engineered nonneural cells incapacitated, whereas donor tissue originating from brain may intrinsically produce various CNS factors allowing correction to proceed despite inactivation of the introduced gene. In fact, CNS-derived tissue may provide as-yet-unrecognized endogenous neuralspecific substances which are equally as beneficial to the host as the gene in question. Thus, future developments in gene delivery to the brain for some conditions may emphasize using neurons or neural progenitors for ex vivo genetic manipulation (Fisher, 1997) and refining techniques for the direct injection of therapeutic genes into neurons in vivo (see Snyder and Fisher, 1996). For a wide variety of conditions, however, using nonneuronal cellular vehicles or even nonbiologic synthetic vehicles may be efficient, effective, and safe strategies for the passive delivery of therapeutic molecules to discrete regions of the CNS. In fact, this approach may come closer than any other to immediate human applications.