An apolipoprotein E modified liposomal nanoparticle: ligand dependent efficiency as a siRNA delivery carrier for mouse-derived brain endothelial cells.

A disorder in the brain endothelium is thought to be closely related to the pathophysiology of brain diseases. A method for delivering nucleic acids (i.e. short interference RNA; siRNA) to the brain endothelium should be an attractive strategy for curing brain disorders. A liposomal nanoparticle containing a proton-ionizable amino lipid was recently developed as a carrier of encapsulated siRNA. The aim of this study was to evaluate the utility of apolipoprotein E (ApoE) as a targeting ligand for mouse brain endothelial cells (MBEC4 cells). The cellular uptake of the ApoE-modified nanoparticles was gradually increased in an ApoE-density dependent manner. Furthermore, the ApoE-modified nanoparticles were taken up via both clathrin and caveolae mediated endocytosis, thus permitting them to avoid lysosomal degradation. Finally, endogenous gene silencing in MBEC4 cells was efficiently achieved depending on the ApoE-modification. Collectively, the ApoE-modified nanoparticle is a promising carrier for delivering nucleic acids to the brain endothelium.