Liposome-mediated NGF gene transfection following neuronal injury: potential therapeutic applications

We have systematically investigated the therapeutic potential of cationic l iposome-mediated neurotrophic gene transfer for treatment of CNS injury. Fo llowing determination of optimal transfection conditions, we examined the e ffects of dimethylaminoethane-carbamoyl-cholesterol (DC-Chol) liposome-medi ated NGF cDNA transfection in injured and uninjured primary septo-hippocamp al cell cultures and rat brains. In in vitro studies, we detected an increa se of NGF mRNA in cultures 1 day after transfection. Subsequent ELISA and P C12 cell biological assays confirmed that cultured cells secreted soluble a ctive NGF into the media from day 2 after gene transfection. Further experi ments showed that such NGF gene transfection reduced the loss of choline ac etyltransferase (ChAT) activity in cultures following calcium-dependent dep olarization injury. In in vivo studies, following intraventricular injectio ns of NGF cDNA complexed with DC-Chol liposomes, ELISA detected nine- to 12 -fold increases of NGF in rat CSF. Further studies showed that liposome/NGF cDNA complexes could attenuate the loss of cholinergic neuronal immunostai ning in the rat septum after traumatic brain injury (TBI). Since deficits i n cholinergic neurotransmission are a major consequence of TBI, our studies demonstrate for the first time that DC-Chol liposome-mediated NGF gene tra nsfection may have therapeutic potential for treatment of brain injury.