Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a rare neurodevelopmental disorder caused by a mutation in the X-linked CDKL5 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 CDKL5 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 CDKL5 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 in vivo. Our data provide proof of concept that i.c.v. delivery of AAV9.Syn.hCDKL5 to neonatal male Cdkl5 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 缺陷病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） 缺陷病 （CDD） 是一种由 X 连锁 CDKL5 基因突变引起的罕见神经发育障碍。CDKL5 是一种丝氨酸/苏氨酸激酶，对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、肌张力减退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 CDKL5 基因递送到患者的大脑应该会提供临床益处。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 CDKL5 基因表达由突触蛋白启动子驱动。在小鼠进行的生物分布研究中，脑室内 （i.c.v.） 注射比脑池内 （i.c.m.） 给药更广泛、更优化。AAV9.Syn.hCDKL5 处理增加了 EB2 的磷酸化，EB2 是一种真正的 CDKL5 底物，在 体内显示出生物活性。我们的数据提供了 icv 递送 AAV9 的概念验证。Syn.hCDKL5 对新生雄性 Cdkl5 敲除小鼠可减少病理学并减少异常行为。在 3e11 至 5e11 载体基因组/g 脑剂量下观察到功能改善，这导致 ≥50% 的神经元转染。在较低剂量下未观察到功能改善，这表明疗效需要广泛分布。