Department of Ophthalmology, University of Florida, Gainesville, FL, USA.
Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA.
Adv Exp Med Biol. 2019;1185:109-112. doi: 10.1007/978-3-030-27378-1_18.
Mutations in more than 80 genes lead to photoreceptor degeneration. Although subretinal delivery of genes to photoreceptor neurons using AAV vectors has proven itself as an efficient therapeutic and investigative tool in various mouse models, the surgical procedure itself could lead to loss of retinal function even in healthy animals, complicating the interpretation of experimental studies and requiring thoroughly designed controls. A noninvasive approach, such as a systemic delivery of genes with AAV through the bloodstream, may serve as a promising direction in tool development. Previous studies have established that AAV9 is capable of crossing the blood-brain and blood-retina barrier and even has a limited capacity to transduce photoreceptors. AAV-PHP.eB is a novel AAV9-based mutant capsid that crosses the blood-brain barrier and efficiently transduces central nervous system in the adult mice. Here, we investigated its ability to cross the blood-retina barrier and transduce retinal neurons. Control experiments demonstrated virtually nonexisting ability of this capsid to transduce retinal cells via intravitreal administration but high efficiency to transduce photoreceptors via subretinal route. Systemic delivery of AAV-PHP.eB in adult mice robustly transduced horizontal cells throughout the entire retina, but not photoreceptors. Our study suggests that AAV-PHP.eB crosses the intra-retinal blood-retinal barrier (IR-BRB), efficiently transduces horizontal cells located adjacent to IR-BRB, but has very limited ability to further penetrate retina and reach photoreceptors.
超过 80 种基因的突变会导致光感受器变性。尽管使用 AAV 载体将基因递送至光感受器神经元的视网膜下给药已被证明是各种小鼠模型中有效的治疗和研究工具，但手术本身即使在健康动物中也可能导致视网膜功能丧失，从而使实验研究的解释变得复杂，并需要进行彻底设计的对照。非侵入性方法，例如通过血液系统用 AAV 全身递送基因，可能是一种很有前途的工具开发方向。先前的研究已经证实，AAV9 能够穿过血脑和血视网膜屏障，甚至具有有限的转导光感受器的能力。AAV-PHP.eB 是一种新型的基于 AAV9 的突变衣壳，可穿过血脑屏障并有效地转导成年小鼠的中枢神经系统。在这里，我们研究了它穿过血视网膜屏障并转导视网膜神经元的能力。对照实验表明，该衣壳通过玻璃体内给药几乎没有转导视网膜细胞的能力，但通过视网膜下途径转导光感受器的效率很高。AAV-PHP.eB 在成年小鼠中的全身性给药可有效地转导整个视网膜的水平细胞，但不能转导光感受器。我们的研究表明，AAV-PHP.eB 穿过视网膜内血视网膜屏障 (IR-BRB)，有效地转导位于 IR-BRB 附近的水平细胞，但进一步穿透视网膜并到达光感受器的能力非常有限。
