MAPK8 and neurodegenerative disease: In the nervous system, the aberrant activation of JNK/c-Jun pathway has been closely associated with excessive neuron apoptosis, which is considered one of the important pathological causes that contribute to neurodegenerative diseases, including AD, PD, and HD, as well as acute brain injury conditions following stroke, ischemia, or bleeding (Sabapathy, 2012; Kumar et al., 2015; Guo et al., 2018).