Introduction:
Alzheimer’s disease (AD) is the leading cause of dementia in late adult life. Emerging evidence shows that microRNAs (miRNAs) play vital roles in the pathogenesis of AD. The aim of the present study was to eluci-date the underlying role of miR-let-7f in oxidative damage in SH-SY5Y cells.

Material and methods:
miRNA microarray analysis was performed to detect the miRNAs’ differential expression in AD patients and normal elderly volun-teers. Cell injury was evaluated on the basis of cell viability and apoptosis. The effect of miR-let-7f on H2O2-induced oxidative damage was estimated after cell transfection. qRT-PCR and western blot were used to measure the expression of miR-let-7f, AKT-2 and apoptosis-related proteins. The target gene of miR-let-7f was analyzed by luciferase reporter gene assay.

Results:
MiR-let-7f was overexpressed in AD patients. When exposed to H2O2 in vitro, SH-SY5Y cells showed significant apoptosis accompanied by up-regulation of miR-let-7f and increased expression of apoptosis-related proteins. In the presence of H2O2, the up-regulation of miR-let-7f significant-ly increased the cell viability and inhibited cell apoptosis, while down-regulation showed the opposite effect. The luciferase reporter assay showed that ATK-2 is the direct target gene of miR-let-7f. Western blot analysis further showed that miR-let-7f negatively regulated ATK-2 expression.

Conclusions:
The up-regulation of miR-let-7f alleviated the H2O2-induced oxidative damage in SH-SY5Y cells by targeting AKT-2. These findings provided a novel perspective in the role of miR-let-7f in pathogenesis of oxidative damage during AD.