Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a rare neurodevelopmental disorder caused by a mutation in the X-linked gene. CDKL5 is a serine/threonine kinase that is critical for axon outgrowth and dendritic morphogenesis as well as synapse formation, maturation, and maintenance. This disorder is characterized by early-onset epilepsy, hypotonia, and failure to reach cognitive and motor developmental milestones. Because the disease is monogenic, delivery of the gene to the brain of patients should provide clinical benefit. To this end, we designed a gene therapy vector, adeno-associated virus (AAV)9.Syn.hCDKL5, in which human gene expression is driven by the synapsin promoter. In biodistribution studies conducted in mice, intracerebroventricular (i.c.v.) injection resulted in broader, more optimal biodistribution than did intra-cisterna magna (i.c.m.) delivery. AAV9.Syn.hCDKL5 treatment increased phosphorylation of EB2, a bona fide CDKL5 substrate, demonstrating biological activity . Our data provide proof of concept that i.c.v. delivery of AAV9.Syn.hCDKL5 to neonatal male knockout mice reduces pathology and reduces aberrant behavior. Functional improvements were seen at doses of 3e11 to 5e11 vector genomes/g brain, which resulted in transfection of ≥50% of the neurons. Functional improvements were not seen at lower doses, suggesting a requirement for broad distribution for efficacy.

中文翻译：

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CDKL5缺乏症基因替代疗法的临床前研究


细胞周期蛋白依赖性激酶样 5 (CDKL5) 缺乏症 (CDD) 是一种罕见的神经发育障碍，由 X 连锁基因突变引起。 CDKL5 是一种丝氨酸/苏氨酸激酶，对于轴突生长和树突形态发生以及突触形成、成熟和维持至关重要。这种疾病的特点是早发性癫痫、肌张力低下以及未能达到认知和运动发育里程碑。由于该疾病是单基因的，因此将基因输送到患者的大脑应该会带来临床益处。为此，我们设计了一种基因治疗载体，腺相关病毒（AAV）9.Syn.hCDKL5，其中人类基因表达由突触蛋白启动子驱动。在小鼠体内进行的生物分布研究中，脑室内 (icv) 注射比小脑延髓池内 (icm) 注射产生更广泛、更优化的生物分布。 AAV9.Syn.hCDKL5 处理增加了 EB2（一种真正的 CDKL5 底物）的磷酸化，证明了生物活性。我们的数据提供了概念证明，即向新生雄性基因敲除小鼠体内注射 AAV9.Syn.hCDKL5 可减少病理学并减少异常行为。在 3e11 至 5e11 载体基因组/g 大脑的剂量下观察到功能改善，导致 ≥50% 的神经元转染。在较低剂量下没有看到功能改善，这表明需要广泛分布才能发挥功效。