MAPT and Alzheimer disease: Since neuroinflammation caused by abnormal microglial polarization is associated with AD pathology, including Aβ production, tau hyperphosphorylation and synaptic impairment, as well as the cognitive decline in AD [2, 4], we detected the regulatory roles of circAPP in the expression of Aβ and p-tau, synaptic morphology, and cognitive function.