# Optimizing lipid nanoparticles for retinal gene editing in the NHP

> **NIH NIH R01** · LEGACY EMANUEL HOSPITAL AND HEALTH CENTER · 2024 · $596,958

## Abstract

PROJECT SUMMARY
Inherited retinal dystrophies (IRDs) are a group of genetically and clinically heterogenous diseases, inherited in
an autosomal dominant, recessive, or X-linked pattern. With an estimated incidence of 1:2000-1:3000, IRDs
are the leading cause of vision loss in persons aged 15 to 45. To date, mutations in 280 distinct genes have
been associated with retinal pathology. Gene augmentation, editing, and silencing are the most attractive
therapeutic strategies for these patients as they correct the causative genomic malfunction. Currently, there is
only one FDA approved gene augmentation therapy for one IRD in this large family of retinal degenerations.
Our long-term goal is to generate novel gene editing platforms for IRDs. The most clinically advanced gene
editing therapeutic for retinal degeneration is EDIT-101, which uses a viral vector (AAV) to deliver the Cas9
endonuclease and two guide RNAs that target the CEP290 gene in Leber Congenital Amaurosis type 10
patients. While this is the first in-vivo CRISPR/Cas9 clinical trial underway to treat retinal degeneration, the trial
is currently paused, suggesting there is room for improvement in the efficacy of this product either through
modulating the gene editing tools, or the delivery platform. Delivering the Cas9 endonuclease in the form of
mRNA, which leads to transient, robust protein expression, would mitigate safety concerns associated with
AAV-mediated Cas9. These safety concerns include persistent expression of Cas9 endonuclease and AAV
integration into the Cas9-induced double strand breaks. Lipid-based nanoparticles (LNPs) are the most
clinically advanced non-viral platform that can encapsulate mRNA and deliver genome editors. Systemic
administration of LNPs, that encapsulate Cas9 mRNA and a guide RNA targeting transthyretin (TTR), has led
to a 90% reduction in misfolded TTR protein in amyloidosis patients. To translate these therapeutic gains
observed in the liver to the retina, we first measured gene editing events following subretinal administration of
an LNP encapsulating Cas9 mRNA and guide RNA in Ai9 mice. In this proposal, we show significant LNP-
mediated gene editing in the murine retina. Additionally, we were one of the first groups to deliver LNPs to the
subretinal space of rhesus macaques and demonstrate their ability to transfect photoreceptors. To advance the
development of LNP-mediated gene editing therapies for IRDs, there are three critical gaps of knowledge
we propose to address in the most clinically relevant model, the nonhuman primate (NHP): 1) determine which
physiochemical features of LNPs facilitate photoreceptor expression of gene editors, 2) evaluate the
immunogenicity of LNPs in the subretinal space, and 3) quantify in-vivo gene editing efficiency in the
photoreceptors. Successful completion of these aims will generate novel LNP platforms that mediate the
expression of gene editors in NHP photoreceptors. This will lead to an understanding of in-vivo g...

## Key facts

- **NIH application ID:** 11220766
- **Project number:** 7R01EY035258-02
- **Recipient organization:** LEGACY EMANUEL HOSPITAL AND HEALTH CENTER
- **Principal Investigator:** Renee Christine Ryals
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $596,958
- **Award type:** 7
- **Project period:** 2024-07-01 → 2030-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11220766

## Citation

> US National Institutes of Health, RePORTER application 11220766, Optimizing lipid nanoparticles for retinal gene editing in the NHP (7R01EY035258-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/11220766. Licensed CC0.

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