Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.
Biomaterials. 2010 Mar;31(8):2417-24. doi: 10.1016/j.biomaterials.2009.11.086. Epub 2009 Dec 9.
Targeted gene therapy can potentially minimize undesirable off-target toxicity due to specific delivery. Neuron-specific gene delivery in the central nervous system is challenging because neurons are non-dividing and also outnumbered by glial cells. One approach is to transfect dividing neural stem and progenitor cells (NSCs and NPCs, respectively). In this work, we demonstrate cell-specific gene delivery to NPCs in the brains of adult mice using a peptide-modified polymeric vector. Tet1, a 12-amino acid peptide which has been shown to bind specifically to neuronal cells, was utilized as a neuronal targeting ligand. The cationic polymer polyethylenimine (PEI) was covalently modified with polyethylene glycol (PEG) for in vivo salt stability and Tet1 for neuron targeting to yield a Tet1-PEG-PEI conjugate. When plasmid DNA encoding the reporter gene luciferase was complexed with Tet1-PEG-PEI and delivered in vivo via an injection into the lateral ventricle, Tet1-PEG-PEI complexes mediated increased luciferase expression levels in brain tissue when compared to unmodified PEI-PEG complexes. In addition, cells transfected by Tet1-PEG-PEI complexes were found to be exclusively adult NPCs whereas untargeted PEG-PEI complexes were found to transfect a heterogenous population of cells. Thus, we have demonstrated targeted, nonviral delivery of nucleic acids to adult NPCs using the Tet1 targeting ligand. These materials could potentially be used to deliver therapeutic genes for the treatment of neurodegenerative diseases.
靶向基因治疗由于具有特定的传递作用，因此可能最大限度地减少不必要的脱靶毒性。在中枢神经系统中进行神经元特异性基因传递具有挑战性，因为神经元不能分裂，而且数量多于神经胶质细胞。一种方法是转染分裂的神经干细胞和祖细胞（分别为 NSCs 和 NPCs）。在这项工作中，我们使用肽修饰的聚合物载体展示了在成年小鼠大脑中 NPC 的特异性基因传递。已经显示出可与神经元细胞特异性结合的 12 个氨基酸肽 Tet1 被用作神经元靶向配体。阳离子聚合物聚乙烯亚胺（PEI）通过聚乙二醇（PEG）共价修饰以提高体内盐稳定性，并用 Tet1 修饰以实现神经元靶向，得到 Tet1-PEG-PEI 缀合物。当编码报告基因荧光素酶的质粒 DNA 与 Tet1-PEG-PEI 复合并通过侧脑室注射体内递送时，与未修饰的 PEI-PEG 复合物相比，Tet1-PEG-PEI 复合物介导的脑组织中荧光素酶表达水平增加。此外，发现经 Tet1-PEG-PEI 复合物转染的细胞仅为成年 NPC，而未靶向的 PEG-PEI 复合物则可转染异质细胞群。因此，我们已经证明了使用 Tet1 靶向配体将核酸靶向递送至成年 NPC。这些材料有可能用于传递治疗神经退行性疾病的治疗基因。
