Schuster Jens, Klar Joakim, Khalfallah Ayda, Laan Loora, Hoeber Jan, Fatima Ambrin, Sequeira Velin Marita, Jin Zhe, Korol Sergiy V, Huss Mikael, Nordgren Ann, Anderlid Britt Marie, Gallant Caroline, Birnir Bryndis, Dahl Niklas
Department of Immunology, Genetics and Pathology, Uppsala University and Science for Life Laboratory, Uppsala, Sweden.
Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden.
Front Mol Neurosci. 2022 Oct 24;15:988993. doi: 10.3389/fnmol.2022.988993. eCollection 2022.
Mowat-Wilson syndrome (MWS) is a severe neurodevelopmental disorder caused by heterozygous variants in the gene encoding transcription factor . Affected individuals present with structural brain abnormalities, speech delay and epilepsy. In mice, conditional loss of Zeb2 causes hippocampal degeneration, altered migration and differentiation of GABAergic interneurons, a heterogeneous population of mainly inhibitory neurons of importance for maintaining normal excitability. To get insights into GABAergic development and function in MWS we investigated ZEB2 haploinsufficient induced pluripotent stem cells (iPSC) of MWS subjects together with iPSC of healthy donors. Analysis of RNA-sequencing data at two time points of GABAergic development revealed an attenuated interneuronal identity in MWS subject derived iPSC with enrichment of differentially expressed genes required for transcriptional regulation, cell fate transition and forebrain patterning. The ZEB2 haploinsufficient neural stem cells (NSCs) showed downregulation of genes required for ventral telencephalon specification, such as FOXG1, accompanied by an impaired migratory capacity. Further differentiation into GABAergic interneuronal cells uncovered upregulation of transcription factors promoting pallial and excitatory neurons whereas cortical markers were downregulated. The differentially expressed genes formed a neural protein-protein network with extensive connections to well-established epilepsy genes. Analysis of electrophysiological properties in ZEB2 haploinsufficient GABAergic cells revealed overt perturbations manifested as impaired firing of repeated action potentials. Our iPSC model of ZEB2 haploinsufficient GABAergic development thus uncovers a dysregulated gene network leading to immature interneurons with mixed identity and altered electrophysiological properties, suggesting mechanisms contributing to the neuropathogenesis and seizures in MWS.
莫瓦特-威尔逊综合征（MWS）是一种严重的神经发育障碍，由编码转录因子的基因中的杂合变异引起。受影响的个体表现出大脑结构异常、语言发育迟缓以及癫痫。在小鼠中，Zeb2的条件性缺失会导致海马体退化、GABA能中间神经元的迁移和分化改变，GABA能中间神经元是一类异质性群体，主要为抑制性神经元，对维持正常兴奋性很重要。为了深入了解MWS中GABA能神经元的发育和功能，我们研究了MWS患者的ZEB2单倍体不足诱导多能干细胞（iPSC）以及健康供体的iPSC。在GABA能神经元发育的两个时间点对RNA测序数据进行分析，结果显示，MWS患者来源的iPSC中，中间神经元身份减弱，转录调控、细胞命运转变和前脑模式形成所需的差异表达基因富集。ZEB2单倍体不足的神经干细胞（NSC）显示出腹侧端脑特化所需基因（如FOXG1）的下调，同时迁移能力受损。进一步分化为GABA能中间神经元细胞后发现，促进大脑皮质和兴奋性神经元的转录因子上调，而皮质标志物下调。差异表达基因形成了一个神经蛋白-蛋白网络，与已确定的癫痫相关基因有广泛联系。对ZEB2单倍体不足的GABA能细胞的电生理特性进行分析，结果显示明显的扰动，表现为重复动作电位的发放受损。因此，我们的ZEB2单倍体不足的GABA能神经元发育iPSC模型揭示了一个失调的基因网络，该网络导致中间神经元不成熟，身份混合且电生理特性改变，提示了MWS神经发病机制和癫痫发作的相关机制。
