Gene delivery of the therapeutic polypeptide erythropoietin to primary brain capillary endothelial cells for protein secretion

The potential for treatment of chronic disorders affecting the CNS is complicated by the inability of several drugs to cross the blood-brain barrier (BBB). None-viral gene therapy applied to brain capillary endothelial cells (BCECs) denotes a novel approach to overcome the restraints in this passage, as turning BCECs into recombinant protein factories by transfection could result in protein secretion into the brain. The non-mitotic BCECs might, however, not be very susceptible to non-viral gene therapy in vivo, since this strategy is believed to be dependent on active cell division. We have, however, recently shown that non-viral gene therapy to non-mitotic BCECs cultured in an in-vitro BBB model was possible without disrupting the barrier properties of the BCECs, and that this was as effective as transfection of dividing BCECs. The transfection efficiency is, however, low, questioning the possible effect of this protein delivery strategy in vivo. The aim of the present study was, therefore, to investigate the possibility of increasing the transfection efficiency using non-viral gene carriers, with the hope of increase the recombinant protein synthesis of erythropoietin, a protein recognized for its neuroprotective potential, from the BCECs. Our study opens for knowledge on, how non-viral gene therapy to BCECs can lead to protein secretion with the perspective of enabling therapeutic proteins to target neurons inside the CNS otherwise inhibited to access due to the restraints of the BBB. This therapeutic strategy could be beneficial in treatment of inherited diseases and classical neurodegenerative disorders.