AAV8-vectored suprachoroidal gene transfer produces widespread ocular transgene expression
Kun Ding, … , Olivier Danos, Peter A. Campochiaro
Kun Ding, … , Olivier Danos, Peter A. Campochiaro
Published October 7, 2019; First published August 13, 2019
Citation Information: J Clin Invest. 2019. https://doi.org/10.1172/JCI129085.
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Categories: Research Article Ophthalmology

AAV8-vectored suprachoroidal gene transfer produces widespread ocular transgene expression

Abstract

There has been great progress in ocular gene therapy, but delivery of viral vectors to the retinal pigmented epithelium (RPE) and retina can be challenging. Subretinal injection, the preferred route of delivery for most applications, requires a surgical procedure that has risks. Herein we report a novel gene therapy delivery approach, suprachoroidal injection of AAV8 vectors, which is less invasive and could be done in an outpatient setting. Two weeks after suprachoroidal injection of AAV8.GFP in rats, GFP fluorescence covered 18.9% of RPE flat mounts and extended entirely around sagittal and transverse sections in RPE and photoreceptors. After 2 suprachoroidal injections of AAV8.GFP, GFP fluorescence covered 30.5% of RPE flat mounts. Similarly, widespread expression of GFP occurred in nonhuman primate and pig eyes after suprachoroidal injection of AAV8.GFP. Compared with subretinal injection in rats of RGX-314, an AAV8 vector expressing an anti-VEGF Fab, suprachoroidal injection of the same dose of RGX-314 resulted in similar expression of anti-VEGF Fab and similar suppression of VEGF-induced vascular leakage. Suprachoroidal AAV8 vector injection provides a noninvasive outpatient procedure to obtain widespread transgene expression in retina and RPE.

Authors

Kun Ding, Jikui Shen, Zibran Hafiz, Sean F. Hackett, Raquel Lima e Silva, Mahmood Khan, Valeria E. Lorenc, Daiqin Chen, Rishi Chadha, Minie Zhang, Sherri Van Everen, Nicholas Buss, Michele Fiscella, Olivier Danos, Peter A. Campochiaro

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Figure 1

Widespread expression of GFP after suprachoroidal injection of AAV8.GFP in rats.

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Widespread expression of GFP after suprachoroidal injection of AAV8.GFP ...
(A) Immediately after suprachoroidal injection of India ink (3 μL) in rats, frozen sections showed increased choroidal thickness on the side of injection that tapered to normal, but ink extended completely around the eye. Scale bar: 1000 μm. High magnification showed ink from the sclera to the basal surface of the RPE (insets; scale bar: 100 μm). (B) Two weeks after suprachoroidal injection of 2.85 × 1010 GCs of AAV8.GFP, 10-μm horizontal frozen sections at the equator showed GFP in the retina and RPE extending around entire circumference of the eye. Scale bar: 500 μm. (C) A retinal flat mount showed high GFP expression in about one-fifth of the retina from anterior edge posteriorly nearly to the optic nerve. Scale bar: 500 μm. (D) There was GFP throughout about one-fifth of a RPE flat mount from the anterior edge posteriorly almost to the optic nerve. Scale bar: 500 μm. (E) Higher magnification of boxed region shows strong GFP fluorescence in some RPE cells and little fluorescence in others. Scale bar: 50 μm. (F) The mean ± SEM level of GFP measured by ELISA was high in retinal or RPE/choroid homogenates at 1 and 2 weeks after suprachoroidal injection (n = 10 for each group). Two weeks after vector injection, an ocular section through the posterior part of the eye near the optic nerve shows strong fluorescence in the RPE, photoreceptor cell bodies, inner segments, and outer segments (G). The same section immunohistochemically stained with anti-GFP antibody (H) and merged with the image in G shows that the fluorescence is due to GFP (I; scale bar: 50 μm). An ocular section from the equator of the eye on the side opposite the site of injection shows strong GFP expression in RPE but in a minority of photoreceptor cell bodies and inner segments (J–L; scale bars: 50 μm). INL, inner nuclear layer; ONL, outer nuclear layer; IS, photoreceptor inner segment; OS, photoreceptor outer segment; RPE, retinal pigmented epithelium.