Department of Oncology and Hematology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
PLoS One. 2011;6(8):e23101. doi: 10.1371/journal.pone.0023101. Epub 2011 Aug 5.
Efficiency and specificity of viral vectors are vital issues in gene therapy. Insertion of peptide ligands into the adeno-associated viral (AAV) capsid at receptor binding sites can re-target AAV2-derived vectors to alternative cell types. Also, the use of serotypes AAV8 and -9 is more efficient than AAV2 for gene transfer to certain tissues in vivo. Consequently, re-targeting of these serotypes by ligand insertion could be a promising approach but has not been explored so far. Here, we generated AAV8 and -9 vectors displaying peptides in the threefold spike capsid domain. These peptides had been selected from peptide libraries displayed on capsids of AAV serotype 2 to optimize systemic gene delivery to murine lung tissue and to breast cancer tissue in PymT transgenic mice (PymT). Such peptide insertions at position 590 of the AAV8 capsid and position 589 of the AAV9 capsid changed the transduction properties of both serotypes. However, both peptides inserted in AAV8 did not result in the same changes of tissue tropism as they did in AAV2. While the AAV2 peptides selected on murine lung tissue did not alter tropism of serotypes 8 and -9, insertion of the AAV2-derived peptide selected on breast cancer tissue augmented tumor gene delivery in both serotypes. Further, this peptide mediated a strong but unspecific in vivo gene transfer for AAV8 and abrogated transduction of various control tissues for AAV9. Our findings indicate that peptide insertion into defined sites of AAV8 and -9 capsids can change and improve their efficiency and specificity compared to their wild type variants and to AAV2, making these insertion sites attractive for the generation of novel targeted vectors in these serotypes.
病毒载体的效率和特异性是基因治疗中的关键问题。将肽配体插入到腺相关病毒（AAV）衣壳的受体结合部位，可以将源自 AAV2 的载体重新靶向到替代的细胞类型。此外，与 AAV2 相比，使用血清型 AAV8 和 -9 进行基因转移到体内某些组织更为有效。因此，通过插入配体来重新靶向这些血清型可能是一种很有前途的方法，但迄今为止尚未得到探索。在这里，我们生成了在三倍旋转衣壳域中显示肽的 AAV8 和 -9 载体。这些肽是从 AAV 血清型 2 的衣壳上展示的肽文库中选择出来的，用于优化系统基因传递到小鼠肺组织和 PymT 转基因小鼠（PymT）的乳腺癌组织。在 AAV8 衣壳的位置 590 和 AAV9 衣壳的位置 589 处插入这些肽改变了这两种血清型的转导特性。然而，插入 AAV8 中的两种肽并没有导致与 AAV2 相同的组织趋向性变化。虽然在小鼠肺组织上选择的 AAV2 肽没有改变血清型 8 和 -9 的趋向性，但插入来自乳腺癌组织的 AAV2 衍生肽增强了这两种血清型的肿瘤基因传递。此外，该肽介导了 AAV8 的强烈但非特异性的体内基因转移，并使 AAV9 的各种对照组织的转导失活。我们的研究结果表明，与野生型变体和 AAV2 相比，肽插入到 AAV8 和 -9 衣壳的特定部位可以改变和提高它们的效率和特异性，使这些插入部位成为在这些血清型中生成新型靶向载体的有吸引力的选择。
