Efforts have also been made to deliver plasmid DNA expressing proteins related to CNS disease, such as the abovementioned NF (e.g., GDNF), tumor inhibitor of growth 4 (ING4), tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL), and angiogenic factors (e.g., VEGF).[49, 277, 278, 279] For instance, Aly et al. intranasally injected GDNF‐encoding plasmid (pGDNF) into a rat model of PD. This evidence concerns the gene GDNF and Parkinson disease.