Epigenetic marks elucidate gene regulatory elements require for human inhibitory interneuron-like progenitors

Gene regulatory elements such as enhancers dynamically regulate gene expression in a tissue-specific manner. However, the transcriptional regulatory elements during human inhibitory interneuron differentiation and their role in neurodevelopmental disorders are unknown. Here, we generate gene regulatory element maps of human inhibitory-like interneurons derived from embryonic stem cells (H9-ESC), permitting large-scale annotation of previously uncharacterized regulatory elements relevant to inhibitory interneuron differentiation. Our analyses identify neuronal progenitor enhancers that likely regulate the expression of transcription factors that are essential for interneuron differentiation. Focusing on dynamic changes in chromatin organization, FOXG1 and ZEB2, where the chromatin organization is changed in interneuron progenitors compared to different stages during the differentiation. Using 4C-seq and an in vivo enhancer assay, we characterized neuronal enhancers at the FOXG1 locus that interact with the FOXG1 promoter region and showed activity patterns that resemble FOXG1 expression. Using CRISPR/Cas9 genome editing, we deleted FOXG1 enhancer/s that reduced FOXG1 expression in glioblastoma cells and altered cell proliferation. Furthermore, a microdeletion proximal to FOXG1 encompassing these neuronal FOXG1 enhancers was found in a patient with Rett-like syndrome, supporting the role of FOXG1 enhancers in this syndrome. Thus, our study elucidates the gene regulatory networks of human inhibitory interneurons. Furthermore, it provides a framework for understanding the impact of non-coding regulatory elements during inhibitory interneuron differentiation, and highlights novel mechanisms underlying neurodevelopmental disorders. Overall design: Profiling histone modifications that are associated with enhancer activity during human ESC diffrentiation to interneuron progenitors