Abstract
Inner ear hair cells are mechanoreceptors responsible for hearing. Pathogenic defects of hair cell-specific genes are one of the major causes of deafness. The BarH class homeobox gene Barhl1 is a deafness gene expressed in developing hair cells, yet the role of Barhl1 during hair cell development remains poorly understood. In the present study, we first established an in vitro differentiation system to efficiently obtain mouse embryonic stem cell (mESC)-derived hair cell-like cells. Subsequently, a mESC line carrying a targeted disruption of Barhl1 was generated using CRISPR/Cas9 technology and subjected to the established in vitro hair cell differentiation protocol. Targeted disruption of Barhl1 does not affect the induction of mESCs toward early primitive ectoderm-like (EPL) cells and otic progenitors but strongly inhibits the differentiation of hair cell-like cells. Using RNA-sequencing and bioinformatics, we further unravel the molecular mechanism underlying Barhl1-mediated hair cell development. Our data demonstrate the essential role of Barhl1 during hair cell development and provide a basis for the treatment of Barhl1 mutation-based deafness.