An AAV packaging system (virus titer 1 ×1 012) over-expressing circNF1-419, when injected into mouse cerebral cortex, showed autophagy enhancing activity by binding Dynamin-1 and AP2B1, delaying senile dementia by regulating aging markers (p21, p35/25, p16) and inflammatory factors (IL-6, IL-10, NF-κB), and by reducing the expression of AD marker proteins Tau, p-Tau, Aβ1-42, and APOE in SAMP8 mice. The gene discussed is APOE; the disease is dementia.