Blood-brain barrier genomics and the use of endogenous transporters to cause drug penetration into the brain.

Blood-brain barrier (BBB) genomics enables the rapid discovery of novel transporters that are expressed at the brain capillary endothelium. The BBB transporters are potential conduits to the brain that therapeutic drugs may use to gain passage across the BBB. Due to the small volume of brain occupied by the endothelium (10(-3) parts of the brain), it is necessary to build a BBB genomics program that is separate from a whole-brain genomics analysis. It is estimated that approximately 15% of all genes selectively expressed at the BBB encode for transporter proteins, and that only approximately 50% of BBB transporters are currently known. The development of a BBB genomics program and the discovery of novel BBB transporters could lead to the invention of new approaches to solving the BBB drug delivery problem.