A significant decrease in both synaptic markers of PSD-95 and synaptophysin was detected in the cortex and hippocampus of AD mice compared with WT mice, while W20/XD4-SPIONs and W20-SPIONs significantly increased the levels of PSD-95 and synaptophysin in the cortex and hippocampus. Here, DLG4 is linked to Alzheimer disease.