Phenylketonuria (PKU) is a liver metabolic disorders mainly caused by a deficiency of the hepatic phenylalanine hydroxylase (PAH) enzyme activity, often leading to severe brain function impairment in patients if untreated or if treatment is delayed. In this study, we utilized dual-AAV8 vectors to deliver a near PAM-less adenine base editor variant, known as ABE8e-SpRY, to treat the PahR408W PKU mouse model carrying a frequent R408W mutation in the Pah gene. Our findings revealed that a single intravenous injection in adult mice and a single intraperitoneal injection in neonatal mice resulted in 19.1% to 34.6% A-to-G editing efficiency at the pathogenic mutation site with minimal bystander edits. Furthermore, the dual-AAV8 treated mice exhibited reduced blood Phe levels to below the therapeutic threshold of 360 μmol L-1 and restored weight and fur color to normal levels. Importantly, the brain function of the mice was restored after the treatment, particularly when administered during the neonatal stage, as levels of monoamine neurotransmitters and metabolites in the brain returned to normal and near-normal levels. Our study demonstrated that ABE8e-SpRY-based base editing could effectively correct the point mutation in the PahR408W PKU mouse model, indicating potential clinical applications for PKU and other genetic diseases.

中文翻译：

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通过在 PahR408W 苯丙酮尿症小鼠模型中进行碱基编辑改善代谢和行为缺陷。


苯丙酮尿症 （PKU） 是一种肝脏代谢紊乱，主要由肝脏苯丙氨酸羟化酶 （PAH） 活性缺乏引起，如果不治疗或延迟治疗，通常会导致患者出现严重的脑功能障碍。在这项研究中，我们利用双 AAV8 载体递送一种接近无 PAM 的腺嘌呤碱基编辑器变体，称为 ABE8e-SpRY，以治疗 Pah 基因中携带频繁 R408W 突变的 PahR408W PKU 小鼠模型。我们的研究结果显示，成年小鼠单次静脉注射和新生小鼠单次腹膜内注射导致致病突变位点的 A-to-G 编辑效率为 19.1% 至 34.6%，旁观者编辑最少。此外，双 AAV8 处理的小鼠表现出血液 Phe 水平降低至 360 μmol L-1 的治疗阈值以下，并将体重和皮毛颜色恢复到正常水平。重要的是，小鼠的大脑功能在治疗后得到了恢复，尤其是在新生儿阶段给药时，因为大脑中单胺类神经递质和代谢物的水平恢复到正常和接近正常的水平。我们的研究表明，基于 ABE8e-SpRY 的碱基编辑可以有效纠正 PahR408W PKU 小鼠模型中的点突变，表明 PKU 和其他遗传疾病具有潜在的临床应用。