For instance, Gomeset al. revealed that reducing P-gp expression by siRNA NPs could enhanceP-gp substrate permeability via modulating drug efflux at the BBB.116 Similarly, PEGylated PLGA NPs were appliedto transport coumarin C75 for the treatment of PD, most probably viathe inhibition of the P-gp efflux pump in hCMEC/D3 cells.117 The BBB-targeted NP induced P-gp down-regulationand consequently increased P-gp substrate permeability across brainmembranes would allow for successful influx of drugs across the BBB. This evidence concerns the gene PGP and Parkinson disease.