Gene Therapy Research Unit, Children's Medical Research Institute and Sydney Children's Hospitals Network, University of Sydney, Westmead, New South Wales, Australia.
Centre for Inflammatory Diseases, Monash University Department of Medicine, Clayton, Victoria.
Hum Gene Ther. 2022 May;33(9-10):560-571. doi: 10.1089/hum.2021.264.
Adeno-associated virus (AAV) vectors are proving to be clinically transformative tools in the treatment of monogenic genetic disease. Rapid ongoing development of this technology promises to not only increase the number of monogenic disorders amenable to this approach but also to bring diseases with complex multigenic and nongenetic etiologies within therapeutic reach. In this study, we explore the broader paradigm of converting the liver into a biofactory for systemic output of therapeutic molecules using AAV-mediated delivery of the endonuclease DNaseI as an exemplar. DNaseI can clear neutrophil extracellular traps (NETs), which are nuclear-protein structures possessing antimicrobial action, also involved in the pathophysiology of clinically troubling immune-mediated diseases. However, a translational challenge is short half-life of the enzyme (<5 h). This study demonstrates that AAV-mediated liver-targeted gene transfer stably induces serum DNaseI activity to >190-fold above physiological levels. In lupus-prone mice (NZBWF1), the activity was maintained for longer than 6 months, the latest time point tested, and resulted in a clear functional effect with reduced renal presence of neutrophils, NETs, IgG, and complement C3. However, treatment in this complex disease model did not extend lifespan, improve serological endpoints, or preserve renal function, indicating there are elements of pathophysiology not accessible to DNaseI in the NZBWF1 model. We conclude that a translational solution to the challenge of short half-life of DNaseI is AAV-mediated gene delivery and that this may be efficacious in treating disease where NETs are a dominant pathological mechanism.
腺相关病毒 (AAV) 载体在治疗单基因遗传疾病方面正被证明是一种具有临床变革性的工具。这项技术的快速发展不仅有望增加可采用这种方法治疗的单基因疾病数量，而且还将使具有复杂多基因和非遗传病因的疾病也能得到治疗。在这项研究中，我们探索了更广泛的范例，即使用 AAV 介导的内切酶 DNaseI 传递将肝脏转化为治疗分子的全身输出的生物工厂，以此为例。DNaseI 可以清除中性粒细胞胞外陷阱 (NETs)，这是一种具有抗菌作用的核蛋白结构，也参与了临床上令人困扰的免疫介导性疾病的病理生理学。然而，一个转化的挑战是酶的半衰期较短（<5h）。本研究表明，AAV 介导的肝靶向基因转移可稳定地将血清中的 DNaseI 活性诱导至生理水平以上 190 倍以上。在狼疮易感小鼠（NZBWF1）中，该活性可维持 6 个月以上，这是测试的最晚时间点，并且导致了一个明显的功能效应，即肾脏中中性粒细胞、NETs、IgG 和补体 C3 的存在减少。然而，在这种复杂疾病模型中的治疗并没有延长寿命、改善血清学终点或保护肾功能，这表明在 NZBWF1 模型中，DNaseI 无法触及某些病理生理学的因素。我们得出结论，解决 DNaseI 半衰期短的转化解决方案是 AAV 介导的基因传递，并且这在 NETs 是主要病理机制的疾病的治疗中可能是有效的。
