Furthermore, signal transduction pathways involved in astrocyte responses in AD, including the Janus kinase (JAK)/STAT3, the calcium/calcineurin/NFAT Pathway, the NFκB, and the MAPK pathways, regulate astrocyte APP processing homeostasis and promote overproduction of neurotoxic factors leading to Aβ accumulation and toxicity [54]. Here, APP is linked to Alzheimer disease.