CTSB and Alzheimer disease: Zhang et al. provided further information about the benefit of valproate, which down-regulated the expression of multiple histone deacetylators (HDACs) both in vivo in AD mouse models and their cultured cells; valproate also decreased the expression of APP secretases through the JNK pathway, reduced Aβ deposition in both the AD cell and mouse models, and significantly improved cognitive function in AD mice [34].