Phenylketonuria (PKU) is an inherited metabolic disorder caused by mutation within phenylalanine hydroxylase (PAH) gene. Loss-of-function of PAH leads to accumulation of phenylalanine in the blood/body of an untreated patient, which damages the developing brain, causing severe mental retardation. Current gene therapy strategies based on adeno-associated vector (AAV) delivery of PAH gene were effective in male animals but had little long-term effects on blood hyperphenylalaninemia in females. Here, we designed a gene therapy strategy using AAV to deliver a human codon-optimized phenylalanine amino lyase in a liver-specific manner. It was shown that PAL was active in lysing phenylalanine when it was expressed in mammalian cells. We produced a recombinant adeno-associated vector serotype 8 (AAV8) viral vector expressing the humanized PAL under the control of human antitrypsin (hAAT) promoter (AAV8-PAL). A single intravenous administration of AAV8-PAL caused long-term correction of hyperphenylalaninemia in both male and female PKU mice (strain Pah^enu2). Besides, no obvious liver injury was observed throughout the treatment process. Thus, our results established that AAV-mediated liver delivery of PAL gene is a promising strategy in the treatment of PKU.

苯丙酮尿症（PKU）是一种由苯丙氨酸羟化酶（PAH）基因突变引起的遗传性代谢疾病。PAH 的功能丧失导致苯丙氨酸在未经治疗的患者的血液/体内积聚，从而损害发育中的大脑，导致严重的智力迟钝。目前基于 PAH 基因的腺相关载体 (AAV) 递送的基因治疗策略对雄性动物有效，但对雌性血液高苯丙氨酸血症几乎没有长期影响。在这里，我们设计了一种基因治疗策略，使用 AAV 以肝脏特异性方式递送人类密码子优化的苯丙氨酸氨基裂合酶。结果表明，当 PAL 在哺乳动物细胞中表达时，它具有裂解苯丙氨酸的活性。我们生产了一种重组腺相关载体血清型 8 (AAV8) 病毒载体，该病毒载体在人抗胰蛋白酶 (hAAT) 启动子 (AAV8-PAL) 的控制下表达人源化 PAL。单次静脉注射 AAV8-PAL 可长期纠正雄性和雌性 PKU 小鼠（Pah 菌株）的高苯丙氨酸血症。^enu2 )。此外，在整个治疗过程中未观察到明显的肝损伤。因此，我们的研究结果表明，AAV 介导的 PAL 基因肝脏递送是治疗 PKU 的有前景的策略。