MAPK9 and Alzheimer disease: This activation of the JNK/SAPK pathway causes lipid peroxidation [93] and alterations of antioxidant enzymes, i.e., HO-1 and SOD1, in AD [94,95], and it upregulates BACE-1 expression, followed by elevated Aβ peptide levels, synaptic dysfunction, and neuronal cell death in AD [96,97].