Gene therapy for Parkinson's disease: Recent achievements and remaining challenges

Gene therapy is the use of nucleic acids as drugs. Thus, ways had to be dev eloped to deliver this new generation of drugs to target tissues. Various v iral and non-viral vectors have been engineered to carry potentially therap eutic nucleic acids into diseased organs or target cells. The brain offers a particular challenge for gene delivery to its constituent cells: it is en cased by the skull, separated from the general circulation by the blood bra in barrier, and made up of mostly non-dividing cells. The skull limits dire ct injection of vectors into the brain, the blood brain barrier inhibits th e easy entry of vectors injected into the bloodstream, and post mitotic tar get cells restrict what type of vector can be used to deliver genes to the brain. We will discuss the main challenges faced by gene delivery to the br ain, i.e. immune responses to the delivery vectors and therapeutic transgen es and length of duration of the therapy specifically as applied to Parkins on's disease. We will also discuss therapeutic strategies. which could be i mplemented to treat Parkinson's disease, and the models in which they have been tested.