1. ¹INSERM UMR U649, CHU-Hotel Dieu, Bât. J. Monnet, 30 Avenue J. Monnet, 44035 Nantes Cedex 01, France
2. ²Service d'Ophtalmologie, CHU-Hotel Dieu, 1 Place Alexis Ricordeau, 44000 Nantes, France
3. ³Laboratoire National de Dépistage du Dopage, 92290 Châtenay-Malabry, France
4. ⁴Service d'Urgences, Ecole Nationale Vétérinaire, 44000 Nantes, France
5. ⁵EFS-Pays de Loire, 44000 Nantes, France

Correspondence: Fabienne Rolling, Fax: +33 2 40 08 74 91. E-mail: fabienne.rolling@univ-nantes.fr

Received 14 November 2005; Revised 13 December 2005; Accepted 13 December 2005.

Abstract

Adeno-associated viral gene therapy has shown promise for the treatment of inherited and acquired retinal disorders. In most applications, regulation of expression is a critical concern for both safety and efficacy. The purpose of our study was to evaluate the ability of the tetracycline-regulatable system to establish long-term transgene regulation in the retina of nonhuman primates. Three rAAV vectors expressing the tetracycline-dependent transactivator (rtTA) under the control of either the ubiquitous CAG promoter or the specific RPE65 promoter (AAV2/5.CAG.TetOn.epo, AAV2/4.CAG.TetOn.epo, and AAV2/4.RPE65.TetOn.epo) were generated and administered subretinally to seven macaques. We demonstrated that repeated inductions of transgene expression in the nonhuman primate retina can be achieved using a Tet-inducible system via rAAV vector administration over a long period (2.5 years). Maximum erythropoietin (EPO) secretion in the anterior chamber depends upon the rAAV serotype and the nature of the promoter driving rtTA expression. We observed that the EPO isoforms produced in the retina differ from one another based on the transduced cell type of origin within the retina and also differ from both the physiological EPO isoforms and the isoforms produced by AAV-transduced skeletal muscle.