These siRNAs efficiently knocked down BACE‐1, which improved the cognitive function of AD mice.[247] Spencer et al. intravenously injected a siRNA‐loaded nanocomplex that targeted α‐syn protein into a PD mouse model, which triggered a significant reduction of α‐syn in the brain of the tested mice.[22] siRNA have also been designed to target oncogenes of GBM to aid cancer cell killing. Here, BACE1 is linked to Parkinson disease.