Gene therapy targeting in the central nervous system

Targeted gene therapy aims at achieving the expression of therapeutic transgenes in specific and restricted cell populations, thus sparing all other cells of the unwanted effects of the gene product. This strategy is particularly appealing for therapy of the central nervous system (CNS), where many different cell types exist, and where the inappropriate expression of a molecule can produce grave consequences. To accomplish the objectives of targeted gene therapy, two different approaches have been developed. The first one consists in creating vectors that will deliver the transgene exclusively to the selected cells, that is manipulating the transductional capacities of the vector, and the second one is based on the transcriptional properties of the transgene, so that it will only be expressed in cells where the appropriate transcriptional machinery is present. Reaching the goals of targeted gene expression will greatly increase the specificity and safety of gene therapy, thus getting us closer to the fulfillment of the expectations generated by this new branch of molecular medicine.