E1 - Nonviral Therapeutic Gene Delivery and Synthetic/Molecular Conjugates
426: Non-Viral Targeted Laser Delivery of Multi-Characteristic Opsin Genes for Treatment of Geographic Atrophy
Type: Oral Abstract Session
Presentation Details
Session Title: Nonviral Approaches for Therapeutic Applications
Purpose: Vision loss in end-stage age-related macular degeneration (AMD) patients, particularly due to geographic atrophy (GA), is linked to the loss of photoreceptors. Highly photosensitive MCO expression in higher-order retinal neurons restores light sensitivity to the retina in patients with permanent photoreceptor loss. Non-virally delivered Multi-Characteristic Opsin (MCO) optogenetic therapy may be a promising treatment strategy for retinal degenerative diseases. Optical Coherence Tomography (OCT)-guided laser-delivery of MCO plasmids achieves spatial targeting of GA lesions while avoiding healthy regions of the peripheral retina. Method: To achieve targeted delivery of MCO, we integrated a near-infrared (NIR) laser beam with an OCT imaging beam to locate retinal lesions. A mixture of MCO plasmids and gold nanorods (GNRs) was intravitreally injected into multiple animal models. Upon laser micro-irradiation, the GNRs cause localized enhancement of laser intensity leading to the formation of nanopores on the targeted cell membranes, thus permeabilizing the membrane to enable precise and site-specific delivery of MCO-plasmids. The efficacy of laser-delivered MCO was evaluated in retinal degeneration (rd) rodent models by immunohistochemistry (IHC) and electrophysiology. The safety and toxicity of this delivery method were evaluated in wild-type rodents and African green monkeys using electrophysiology, OCT, intraocular pressure (IOP) monitoring, and IHC. Results: Expression of MCO in the retina led to long-term expression up to 1 yr. Enhanced electroretinography (ERG) and visually evoked cortical activities in rd animals were observed, which correlated with MCO expression. No observed adverse effect level (NOAEL) was determined for GNR, plasmids, and laser doses. No noticeable decline in ERG, retina thickness (via OCT), increase in cell death, or increase in immune cell response (via IHC) was observed in the therapeutic dose range in wild-type rodents and monkeys. Robust MCO delivery through the internal limiting membrane (ILM) in monkeys, as visualized by fundus imaging of the reporter (mCherry) fluorescence, led to functional improvement, measured by redERG, attributed to MCO's broadband activation spectrum. Conclusion: The safety and efficacy of non-viral spatially targeted laser-delivery of MCO observed in multiple animal models offer an opportunity for efficient and targeted therapeutic gene expression in specific retinal cells within GA lesions. This establishes the utility of the method for translational applications while avoiding immune rejection and adverse events typical of virally delivered gene therapies.
Plain Language Summary
In patients with advanced age-related macular degeneration, vision loss, due to geographic atrophy, is connected to the loss of light-sensing cells. We explored a non-viral OCT-guided laser-delivery of ambient-light activatable Multi-Characteristic Opsin (MCO) to treat retinal degenerative diseases. This method precisely targets GA lesions while sparing healthy peripheral regions. Using a near-infrared laser and gold nanorods, we delivered MCO plasmids into animal models. Laser micro-irradiation, guided by OCT, created nanopores in targeted cells, enabling precise MCO delivery. We assessed efficacy in retinal-degeneration rodent models and safety in wild-type rodents and monkeys. MCO expression persisted for long-term, improving retinal function in animals. No adverse effects were observed in safety evaluations, indicating a therapeutic window. MCO delivery in monkeys led to robust expression and functional improvement. This non-viral laser-delivery method shows promise for targeted gene therapy in specific retinal cells, offering translational potential with enhanced safety compared to traditional viral gene therapies.
Samarendra K. Mohanty1, Sanghoon Kim2, Subrata Batabyal2, Michael Carlson2, Amir Singh1, Adnan Dibas2, Najam Sharif1
1Nanoscope Therapeutics Inc, Dallas, TX,2Nanoscope Technologies LLC, Bedford, TX"
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