Representative in vivo data show that transferrin–PPI G3 dendriplexes deliver plasmid DNA to mouse brain with >2-fold higher gene expression than untargeted controls after intravenous administration [89]; histidine–maltose–coated PPI G4 increases brain levels after intranasal dosing and preserves cognition in an Alzheimer’s disease (AD) mouse model [90]; and Angiopep-2–PEG–PPI formulations enhance LRP1-mediated glioma targeting and chemotherapeutic delivery [91]. The gene discussed is LRP1; the disease is Alzheimer disease.