Histone acetylation and deacetylation correlate with diverse biological phenomena through gene transcription. Histone deacetylases (HDACs) regulate deacetylation of histones and other proteins. However, as a member of the HDAC family, HDAC8 function during neurodevelopment is currently unknown. Therefore, we investigated HDAC8 function during neurodevelopment by examining embryoid body (EB) formation in P19 cells. HDAC8-selective inhibitor (NCC-149) (HDAC8i)-treated cells showed smaller EBs than non -treated cells, as well as reduced expression levels of the neuronal marker, NeuN. Additionally, HDAC8i treatment led to inhibition of cellular proliferation by G2/M phase accumulation and down regulated cyclin A2 and cyclin B1 gene expression. Furthermore, two independent HDAC8 knockout cell lines were established by CRISPR-Cas9, which resulted in smaller EBs, similar to HDAC8i-treated cells. These results suggest that HDAC8 regulates neural differentiation by exerting control of EB formation. (C) 2018 Elsevier Inc. All rights reserved.