Epigenetic insights into GABAergic development in Dravet Syndrome iPSC and therapeutic implications

Dravet syndrome (DS) is a devastating early onset refractory epilepsy syndrome caused by variants in the SCN1A gene. A disturbed GABAergic interneuron function is implicated in the progression to DS but the underlying developmental and pathophysiological mechanisms remain elusive, in particularly at the chromatin level. In this study, we utilized induced pluripotent stem cells (iPSCs) derived from DS cases and healthy donors to model disease-associated epigenetic abnormalities of GABAergic development. Employing the ATAC-Seq technique, we assessed chromatin accessibility at multiple time points (Day 0, Day 19, Day 35, and Day 65) of GABAergic differentiation. Additionally, we elucidated the effects of the commonly used anti-seizure drug valproic acid (VPA) on chromatin accessibility in GABAergic cells. The distinct dynamics in chromatin profile of DS iPSC predicted accelerated early GABAergic development, evident at D19, and diverged further from the pattern in control iPSC with continued differentiation, indicating a disrupted GABAergic maturation. Exposure to VPA at D65 reshaped the chromatin landscape at a variable extent in different iPSC-lines and rescued the observed dysfunctional development in some DS iPSC-GABA. This study provides the first comprehensive investigation on the chromatin landscape of GABAergic differentiation in DS-patient iPSC, offering valuable insights into the epigenetic dysregulations associated with interneuronal dysfunction in DS. Moreover, our detailed analysis of the chromatin changes induced by VPA in iPSC-GABA holds the potential to improve development of personalized and targeted anti-epileptic therapies. Overall design: Dynamic change of chromatin accessbility in GABAergic development from Dravet Syndrome iPSC

德雷维特综合征（Dravet syndrome, DS）是一种由SCN1A基因变异引发的毁灭性早发性难治性癫痫综合征。目前认为γ-氨基丁酸能中间神经元功能紊乱参与了DS的病情进展，但其背后的发育及病理生理机制仍不明确，尤其在染色质层面。本研究利用源自DS患者与健康供体的诱导多能干细胞（induced pluripotent stem cells, iPSCs），构建了模拟疾病相关γ-氨基丁酸能神经元发育表观遗传异常的模型。通过ATAC测序（ATAC-Seq）技术，我们评估了γ-氨基丁酸能神经元分化多个时间节点（第0天、第19天、第35天及第65天）的染色质可及性。此外，我们还阐明了常用抗癫痫药物丙戊酸（valproic acid, VPA）对γ-氨基丁酸能神经元染色质可及性的影响。DS患者iPSCs的染色质谱呈现独特的动态变化，提示其早期γ-氨基丁酸能神经元发育加速，这一现象在第19天即可观测到；随着分化持续，其染色质模式与对照iPSCs的差异进一步扩大，表明γ-氨基丁酸能神经元的成熟过程遭到破坏。在第65天给予VPA处理后，不同iPSC系的染色质景观均出现不同程度的重塑，且部分DS患者iPSC来源的γ-氨基丁酸能神经元的发育功能缺陷得到挽救。本研究首次全面探究了DS患者iPSC中γ-氨基丁酸能神经元分化的染色质景观，为解析DS中间神经元功能异常相关的表观遗传失调提供了宝贵见解。此外，我们对VPA诱导的iPSC来源γ-氨基丁酸能神经元染色质变化的详细分析，有望推动个性化靶向抗癫痫治疗的开发。整体实验设计：德雷维特综合征患者iPSC的γ-氨基丁酸能神经元发育过程中染色质可及性的动态变化。