Distinct H3K27me3 and H3K27ac Modifications in Neural Tube Defects Induced by Benzo[a]pyrene

The pathological mechanisms of neural tube defects (NTDs) are not yet fully understood. Although the dysregulation of histone modification in NTDs is recognized, it remains to be fully elucidated on a genome-wide level. We profiled genome-wide H3K27me3 and H3K27ac occupancy by CUT&Tag in neural tissues from ICR mouse embryos with benzo[a]pyrene (BaP)-induced NTDs (250 mg kg^-1) at E9.5. Furthermore, we performed RNA sequencing (RNA-seq) to investigate the regulation of histone modifications on gene expressions. Gene ontology and KEGG analysis were conducted to predict pathways involved in the development of NTDs. Our analysis of histone 3 lysine 27 modification in BaP-NTD neural tissues compared to BaP-nonNTD revealed 6045 differentially trimethylated regions and 3104 acetylated regions throughout the genome, respectively. The functional analysis identified a number of pathways uniquely enriched for BaP-NTD embryos, including known neurodevelopment related pathways such as anterior/posterior pattern specification, ephrin receptor signaling pathway, neuron migration and neuron differentiation. RNA-seq identified 423 differentially expressed genes (DEGs) between BaP-NTD and BaP-nonNTD group. The combination analysis of CUT&Tag and RNA-seq found that 55 DEGs were modified by H3K27me3 and 25 by H3K27ac in BaP-NTD, respectively. In the transcriptional regulatory network, transcriptional factors including Srsf1, Ume6, Zbtb7b, and Cad were predicated to be involved in gene expression regulation. In conclusion, our results provide an overview of histone modifications during neural tube closure and demonstrate a key role of genome-wide alterations in H3K27me3 and H3K27ac in NTDs corresponding with changes in transcription profiles.