GENE DELIVERY INTO NEURONAL AND GLIAL-CELLS BY USING A REPLICATION-DEFICIENT ADENOVIRUS VECTOR - PROSPECTS FOR NEUROLOGICAL GENE-THERAPY

We have used a recombinant adenovirus vector (El(-)) expressing beta-g alactosidase to explore a novel mechanism with which to transfer genes into cells of the central nervous system (CNS). The replication-defic ient adenovirus vector expressing beta-galactosidase (RAd35) was propa gated on a permissive helper cell line (293 cells). High level protein expression from the human cytomegalovirus immediate early promoter (h CMV IE) was obtained in a target cell population of RAd35 infected cul tured neuronal and glial cell lines. Light microscopy showed that over 50% of the glial cells studied expressed beta-galactosidase. Followin g retinoic acid treatment, RAd35 infected cell lines ND7/23, NG108 and NTera2, showed beta-galactosidase expression in up to 90% of the cell s. In addition, these cells showed morphological evidence of different iation into neurons. This pattern of P-galactosidase expression was al so observed in primary rat cerebella granule neuron cultures. In vivo studies were performed in Balb/c mice following direct intracranial in jections of RAd35 into the brain. Cell sections showed a localised sta ining in the brain at the site of injection of the virus. Non-replicat ing adenovirus vectors are therefore highly efficient systems for deli vering a transgene into brain cells. However, their broad cell tropism may limit their applications for genetic disorders in which a specifi c cell type is to be targeted for gene therapy. To address this proble m, we have constructed adenovirus vectors which contain specific neuro nal promoters and are currently assessing in vitro expression.