In another study, the acetylation of histone H4 in the glucose-regulated protein (GRP78) promoter, was increased in the DKD group, compared with controls; valproate reversed apoptosis by increasing the acetylation of histone H4 in the GRP78 promoter and decreasing the acetylation of histone H4 in the C/EBP-homologous protein (CHOP) promoter, two promoters that encode proteins related to ER stress [81]. This evidence concerns the gene DDIT3 and diabetic kidney disease.