The intended application target of the HPAESG-1/MC DNA polyplexes is neurodegenerative diseases, and thus a therapeutic gene—nerve growth factor (NGF) encoding plasmid PP NGF (7.7 kbp) and its MC construct MC NGF (3.7 kbp) were further constructed and used for transfection in Neu7 and primary astrocytes. The gene discussed is NGF; the disease is neurodegenerative disease.