Targeted delivery of proteins across the blood–brain barrier

Treatment of many neuronal degenerative disorders will require delivery of a therapeutic protein to neurons or glial cells across the whole CNS. The presence of the blood-brain barrier hampers the delivery of these proteins from the blood, thus necessitating a new method for delivery. Receptors on the blood-brain barrier bind ligands to facilitate their transport to the CNS; therefore, we hypothesized that by targeting these receptors, we may be able to deliver proteins to the CNS for therapy. Here, we report the use of the lentivirus vector system to deliver the lysosomal enzyme glucocerebrosidase and a secreted form of GFP to the neurons and astrocytes in the CNS. We fused the low-density lipoprotein receptor-binding domain of the apolipoprotein B to the targeted protein. This approach proved to be feasible for delivery of the protein and could possibly be used as a general method for delivery of therapeutic proteins to the CNS.