Wang Yuqiu, Yang Chen, Hu Hanyang, Chen Chen, Yan Mengdi, Ling Feixiang, Wang Kathy Cheng, Wang Xintao, Deng Zhe, Zhou Xinyue, Zhang Feixu, Lin Sen, Du Zengmin, Zhao Kai, Xiao Xiao
School of Bioengineering, East China University of Science and Technology, Shanghai 200237, China.
School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China.
Mol Ther Nucleic Acids. 2022 Mar 21;28:293-306. doi: 10.1016/j.omtn.2022.03.017. eCollection 2022 Jun 14.
Impressive achievements in clinical trials to treat hemophilia establish a milestone in the development of gene therapy. It highlights the significance of AAV-mediated gene delivery to liver. AAV5 is a unique serotype featured by low neutralizing antibody prevalence. Nevertheless, its liver infectivity is relatively weak. Consequently, it is vital to exploit novel AAV5 capsid mutants with robust liver tropism. To this aim, we performed AAV5-NNK library and barcode screening in mice, from which we identified one capsid variant, called AAVzk2. AAVzk2 displayed a similar yield but divergent post-translational modification sites compared with wild-type serotypes. Mice intravenously injected with AAVzk2 demonstrated a stronger liver transduction than AAV5, roughly comparable with AAV8 and AAV9, with undetectable transduction of other tissues or organs such as heart, lung, spleen, kidney, brain, and skeletal muscle, indicating a liver-specific tropism. Further studies showed a superior human hepatocellular transduction of AAVzk2 to AAV5, AAV8 and AAV9, whereas the seroreactivity of AAVzk2 was as low as AAV5. Overall, we provide a novel AAV serotype that facilitates a robust and specific liver gene delivery to a large population, especially those unable to be treated by AAV8 and AAV9.
治疗血友病的临床试验取得了令人瞩目的成就，为基因治疗的发展树立了一个里程碑。这突出了腺相关病毒（AAV）介导的基因传递至肝脏的重要性。AAV5是一种独特的血清型，其特点是中和抗体流行率低。然而，它对肝脏的感染性相对较弱。因此，开发具有强大肝脏嗜性的新型AAV5衣壳突变体至关重要。为此，我们在小鼠中进行了AAV5-NNK文库和条形码筛选，从中鉴定出一种衣壳变体，称为AAVzk2。与野生型血清型相比，AAVzk2的产量相似，但翻译后修饰位点不同。静脉注射AAVzk2的小鼠肝脏转导比AAV5更强，大致与AAV8和AAV9相当，而心脏、肺、脾、肾、脑和骨骼肌等其他组织或器官未检测到转导，表明具有肝脏特异性嗜性。进一步研究表明，AAVzk2对人肝细胞的转导优于AAV5、AAV8和AAV9，而AAVzk2的血清反应性与AAV5一样低。总体而言，我们提供了一种新型AAV血清型，有助于向大量人群，尤其是那些无法用AAV8和AAV9治疗的人群进行强大而特异性的肝脏基因传递。
