APP and Alzheimer disease: Consistent with the above studies, in the present study, miR-338-5p overexpression rescued impaired spatial learning and memory and decreased amyloid plaque deposition in APP/PS1 mice, which suggested that decreased miR-338-5p expression contributed to cognitive dysfunction and Aβ accumulation in the progression of AD, and also implied that miR-338-5p might be a promising therapeutic target for AD treatment.