Department of Biochemistry, University of Zurich, Winterthurerstr, 190, 8057, Zurich, Switzerland.
Department of Molecular Life Science, University of Zurich, Winterthurerstr, 190, 8057, Zurich, Switzerland.
Nat Commun. 2018 Jan 31;9(1):450. doi: 10.1038/s41467-017-02707-6.
Most systemic viral gene therapies have been limited by sequestration and degradation of virions, innate and adaptive immunity, and silencing of therapeutic genes within the target cells. Here we engineer a high-affinity protein coat, shielding the most commonly used vector in clinical gene therapy, human adenovirus type 5. Using electron microscopy and crystallography we demonstrate a massive coverage of the virion surface through the hexon-shielding scFv fragment, trimerized to exploit the hexon symmetry and gain avidity. The shield reduces virion clearance in the liver. When the shielded particles are equipped with adaptor proteins, the virions deliver their payload genes into human cancer cells expressing HER2 or EGFR. The combination of shield and adapter also increases viral gene delivery to xenografted tumors in vivo, reduces liver off-targeting and immune neutralization. Our study highlights the power of protein engineering for viral vectors overcoming the challenges of local and systemic viral gene therapies.
大多数全身性病毒基因治疗方法都受到病毒粒子的隔离和降解、先天和适应性免疫以及靶细胞内治疗基因沉默的限制。在这里，我们设计了一种高亲和力的蛋白质外壳，保护最常用于临床基因治疗的载体，即人类腺病毒 5 型。我们使用电子显微镜和晶体学技术证明了通过六聚体屏蔽 scFv 片段在病毒粒子表面的大量覆盖，该片段三聚化以利用六聚体对称性并获得亲和力。该屏蔽可减少肝脏中病毒粒子的清除。当带有接头蛋白的屏蔽颗粒被装备时，病毒粒子将其有效载荷基因递送到表达 HER2 或 EGFR 的人癌细胞中。屏蔽和接头的组合还增加了体内异种移植肿瘤中病毒基因的传递，减少了肝脏的非靶向性和免疫中和。我们的研究强调了蛋白质工程对于病毒载体的力量，该载体克服了局部和全身病毒基因治疗的挑战。
