Abstract
Given that histone acetylation via histone acetyltransferases (HATs) and histone deacetylases (HDACs) is significant in memory formation, HDAC2 has been thoroughly investigated as a potential therapeutic target for the treatment of cognitive dysfunction. Although HDAC inhibitors have been discovered through in vitro enzyme assay, off-target effects on other HDACs are common due to their conserved catalytic domains. Each HDAC could be regulated by specific intracellular molecular mechanisms, raising the possibility that a cell-based assay could identify selective inhibitors targeting specific HDACs through their regulatory mechanisms. Here, we propose a versatile, cell-based reporter system for screening HDAC2 inhibitors. Through RNA-sequencing from human cultured neuronal cells, we determined that expression of a transcriptional repressor, inhibitor of DNA binding 1 (ID1), is increased by knockdown of HDAC2. We also established the knock-in neuronal cell lines of a bioluminescence reporter gene to ID1. The knock-in cell lines showed significant reporter activity by known HDAC inhibitors and by HDAC2-knockdown but not by HDAC1-knockdown. Thus, our neuronal cell-based reporter system is a promising method for screening the specific inhibitors of HDAC2 but not HDAC1, by potentially targeting not only HDAC2, but also the regulatory mechanisms of HDAC2 in neurons.