Efficient transduction and optogenetic stimulation of retinal bipolar cells by a synthetic adeno‐associated virus capsid and promoter

• Published in: EMBO molecular medicine Vol. 6; no. 9; pp. 1175 - 1190
• Main Authors: Cronin, Therese, Vandenberghe, Luk H, Hantz, Péter, Juttner, Josephine, Reimann, Andreas, Kacsó, Ágota–Enikő, Huckfeldt, Rachel M, Busskamp, Volker, Kohler, Hubertus, Lagali, Pamela S, Roska, Botond, Bennett, Jean
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.09.2014; EMBO Press; Wiley Open Access; Blackwell Publishing Ltd; Springer Nature
• Subjects: adeno‐associated virus; Animals; Binding sites; Bioengineering; Bipolar cells; Blindness; capsid library; Clinical trials; Dependovirus - genetics; EMBO16; EMBO27; Experiments; Ganglion cells; Gene expression; Gene therapy; Genetic Vectors; HEK293 Cells; Heparan sulfate; Humans; Imaging; Libraries; Life Sciences; Light; Mice; Mice, Inbred C57BL; multi‐electrode array; Mutagenesis; Mutagenesis, Site-Directed; Neurobiology; Neurons and Cognition; optogenetics; Photoreceptors; promoter optimization; Promoter Regions, Genetic; Research Article; Retina; Retinal Bipolar Cells - virology; Transduction, Genetic - methods; Vectors (Biology); capsid library; adeno‐associated virus; promoter optimization; multi‐electrode array; optogenetics; Neuroscience; adeno-associated virus; promoter optimization Subject Categories Genetics; Gene Therapy & Genetic Disease; multi-electrode array
• ISSN: 1757-4676; 1757-4684; 1757-4684
• DOI: 10.15252/emmm.201404077

In this report, we describe the development of a modified adeno‐associated virus (AAV) capsid and promoter for transduction of retinal ON‐bipolar cells. The bipolar cells, which are post‐synaptic to the photoreceptors, are important retinal targets for both basic and preclinical research. In particular, a therapeutic strategy under investigation for advanced forms of blindness involves using optogenetic molecules to render ON‐bipolar cells light‐sensitive. Currently, delivery of adequate levels of gene expression is a limiting step for this approach. The synthetic AAV capsid and promoter described here achieves high level of optogenetic transgene expression in ON‐bipolar cells. This evokes high‐frequency (~100 Hz) spiking responses in ganglion cells of previously blind, rd1 , mice. Our vector is a promising vehicle for further development toward potential clinical use. Synopsis An engineered genetically modified adeno‐associated virus is shown here to efficiently and specifically drive the optogenetic molecule channelrhodopsin‐2 in ON‐bipolar cells, rendering them light sensitive and restoring retinal function in blind rd1 mice. A synthetic AAV capsid and modified bipolar‐cell specific promoter were developed to enhance transgene expression in retinal bipolar cells. The new virus transduced at least 59% of ON‐bipolar cells in mouse retina. In the blind rd1 mouse the virus was used to drive expression of optogenetic channels at levels high enough to elicit strong and robust spiking responses from the ganglion cells. This new virus‐promoter combination is thus presented as a candidate vector for clinical intervention in advanced forms of retinal degeneration. Graphical Abstract An engineered genetically modified adeno‐associated virus is shown here to efficiently and specifically drive the optogenetic molecule channelrhodopsin‐2 in ON‐bipolar cells, rendering them light sensitive and restoring retinal function in blind rd1 mice.