The SLC6A1 gene encodes the gamma-aminobutyric acid (GABA) transporter GAT-1, the deficiency of which is associated with infantile encephalopathy with intellectual disability. We designed two AAV9 vectors, with either the JeT or MeP promoter, and conducted preclinical gene therapy studies using heterozygous and homozygous Slc6a1 KO mice at different developmental ages and various routes of administration. Neonatal intracerebroventricular administration of either vector resulted in significantly normalized EEG patterns in Slc6a1-/- or Slc6a1+/- mice, as well as improvement in several behavioral phenotypes of Slc6a1-/- mice. However, some mortality and adverse effects were observed in neonatal-treated mice. Intrathecal administration of either vector at postnatal day (PND) 5 normalized EEG patterns in Slc6a1+/- mice, but in Slc6a1-/- mice the treatment only rescued nest building without impact on EEG. Both vectors were well-tolerated in all mice treated at PND5 or later (including WT mice), up to 1 year post-injection. Overall, our data demonstrate compelling efficacy when mice are treated at an early development age. We also identified that outside of the neonatal treatment window, the severe homozygous KO model is more refractory to treatment, whereas our treatments in the heterozygous mice, which genotypically match human patients, have resulted in stronger benefits.

中文翻译：

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AAV9/SLC6A1 基因治疗可挽救 Slc6a1-/- 小鼠的异常脑电图模式和认知行为缺陷。


SLC6A1 基因编码 γ-氨基丁酸 （GABA） 转运蛋白 GAT-1，其缺乏与伴有智力障碍的婴儿脑病有关。我们设计了两个 AAV9 载体，具有 JeT 或 MeP 启动子，并使用不同发育年龄和不同给药途径的杂合子和纯合子 Slc6a1 KO 小鼠进行了临床前基因治疗研究。任一载体的新生儿脑室内给药导致 Slc6a1-/- 或 Slc6a1+/- 小鼠的脑电图模式显著正常化，以及 Slc6a1-/-小鼠的几种行为表型的改善。然而，在新生儿治疗的小鼠中观察到一些死亡率和不良反应。在出生后日 （PND） 5 鞘内施用任一载体使 Slc6a1 + / - 小鼠的脑电图模式正常化，但在 Slc6a1 - / - 小鼠中，治疗仅挽救了筑巢，而对脑电图没有影响。两种载体在注射后长达 1 年的所有 PND5 或更高剂量处理的小鼠 （包括 WT 小鼠） 中均具有良好的耐受性。总体而言，我们的数据表明，当小鼠在早期发育年龄接受治疗时，具有令人信服的疗效。我们还发现，在新生儿治疗窗口之外，严重的纯合 KO 模型对治疗更难治，而我们在基因型与人类患者匹配的杂合子小鼠中的治疗产生了更强的益处。