215. Dimerizer-Regulated AADC Expression with Two ...

CENTRAL NERVOUS SYSTEM I 215. Dimerizer-Regulated AADC Expression with Two AAV Vectors in 6-OHDA Lesioned Rats Laura M. Sanftner,1 Victor M. Rivera,2 Lan Feng,1 Lori Berk,2 John R. Forsayeth,1 Tim Clackson,2 Janet Cunningham.1 1 Neurobiology, Avigen Inc., Alameda, CA; 2ARIAD Gene Therapeutics, Cambridge, MA. Recombinant AAV vectors containing the dimerizer-inducible system of transcriptional activation provide a promising strategy for regulated control of therapeutic gene expression in the CNS. To test the feasibility of applying this approach to our current treatment for Parkinson’s disease, we explored regulation of expression of the enzyme Aromatic L-Amino Acid Decarboxylase (AADC) in rat striatum by means of a regulated AAV vector system. Expression of the AADC transgene was made dependent on reconstitution of a functional transcription factor (TF) by the dimerizer rapamycin. Two vectors were constructed: 1) AAV-CMV-TF and 2) AAVZ12-hAADC. We evaluated them in vivo in a rodent model of Parkinson’s disease. A 1:1 combination (3x1010 vg of each vector) was infused ipsilaterally into unilaterally 6-OHDA-lesioned rats. Induction of transgene expression was achieved via intraperitoneal administration of rapamycin at designated time points. Since increased expression of AADC in the lesioned striatum correlates with increased conversion of L-dopa to dopamine, we would expect to see altered behavioral rotational response to 5mg/kg L-dopa. This parameter was evaluated six times during the course of the experiment. The rotational response to L-dopa in the vector-infused (+) rapamycin group was significantly increased (P