DDIT3 and Alzheimer disease: In this study, we incubated organotypic slices from adult rabbit hippocampus with 27-OHC, in the presence or absence of siRNA to gadd153, and determined the effects on levels of Aβ, phosphorylated tau, ROS, oxidative and ER stress, iron homeostasis and apoptosis-regulatory proteins, which are all relevant to AD pathology.