MAPT and Alzheimer disease: Whether LPS-induced TLR4 signaling impacts ceramide C18 synthesis in inflammatory-activated microglial cells must be elucidated all the more so because the level of C18 ceramide is increased in the cerebrospinal fluid of patients with AD and positively correlated with T-tau among the cohort of patients at risk of or at the early stages of dementia, suggesting its role in neurodegeneration [67].