[Research Articles] In Vivo-Directed Evolution of a New Adeno-Associated Virus for Therapeutic Outer Retinal Gene Delivery from the Vitreous

Sci Transl Med 12 June 2013:
Vol. 5, Issue 189, p. 189ra76
Sci. Transl. Med. DOI: 10.1126/scitranslmed.3005708 BLINDNESS Deniz Dalkara1,*, Leah C. Byrne1,*, Ryan R. Klimczak2, Meike Visel2, Lu Yin3, William H. Merigan3, John G. Flannery1,2,† and David V. Schaffer1,2,4,†

1Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720–1462, USA.

2Department of Molecular and Cellular Biology, University of California, Berkeley, CA 94720–1462, USA.

3Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY 14642, USA.

4Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720–1462, USA. ?†Corresponding author. E-mail: schaffer{at}berkeley.edu (D.V.S.); flannery{at}berkeley.edu (J.G.F.) ?* These authors contributed equally to this work.

Inherited retinal degenerative diseases are a clinically promising focus of adeno-associated virus (AAV)–mediated gene therapy. These diseases arise from pathogenic mutations in mRNA transcripts expressed in the eye’s photoreceptor cells or retinal pigment epithelium (RPE), leading to cell death and structural deterioration. Because current gene delivery methods require an injurious subretinal injection to reach the photoreceptors or RPE and transduce just a fraction of the retina, they are suitable only for the treatment of rare degenerative diseases in which retinal structures remain intact. To address the need for broadly applicable gene delivery approaches, we implemented in vivo–directed evolution to engineer AAV variants that deliver the gene cargo to the outer retina after injection into the eye’s easily accessible vitreous humor. This approach has general implications for situations in which dense tissue penetration poses a barrier for gene delivery. A resulting AAV variant mediated widespread delivery to the outer retina and rescued the disease phenotypes of X-linked retinoschisis and Leber’s congenital amaurosis in corresponding mouse models. Furthermore, it enabled transduction of primate photoreceptors from the vitreous, expanding its therapeutic promise.

Copyright © 2013, American Association for the Advancement of ScienceCitation: D. Dalkara, L. C. Byrne, R. R. Klimczak, M. Visel, L. Yin, W. H. Merigan, J. G. Flannery, D. V. Schaffer, In Vivo–Directed Evolution of a New Adeno-Associated Virus for Therapeutic Outer Retinal Gene Delivery from the Vitreous. Sci. Transl. Med. 5, 189ra76 (2013).

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