Mutations in the photoreceptor-specific flippase ABCA4 are associated with Stargardt disease and many other forms of retinal degeneration that currently lack curative therapies. Gene replacement is a logical strategy for ABCA4-associated disease, particularly given the current success of traditional viral-mediated gene delivery, such as with adeno-associated viral (AAV) vectors. However, the large size of the ABCA4 cDNA (6.8 kbp) has hampered progress in the development of genetic treatments. Nonviral DNA nanoparticles (NPs) can accommodate large genes, unlike traditional viral vectors, which have capacity limitations. We utilized an optimized DNA NP technology to subretinally deliver ABCA4 to Abca4-deficient mice. We detected persistent ABCA4 transgene expression for up to 8 months after injection and found marked correction of functional and structural Stargardt phenotypes, such as improved recovery of dark adaptation and reduced lipofuscin granules. These data suggest that DNA NPs may be an excellent, clinically relevant gene delivery approach for genes too large for traditional viral vectors.

These data indicate that the Ins2(Akita) mouse is a good model for later-onset DR, modeling both early and some late disease signs. Furthermore, this work suggests that this model may be suitable for testing and development of targeted DR therapies.

Age-related macular degeneration (AMD) is the foremost cause of irreversible blindness in people over the age of 65 especially in developing countries. Therefore, an exploration of effective and alternative therapeutic interventions is an unmet medical need. It has been established that oxidative stress plays a key role in the pathogenesis of AMD, and hence, neutralizing oxidative stress is an effective therapeutic strategy for treatment of this serious disorder. Owing to autoregenerative properties, nanoceria has been widely used as a nonenzymatic antioxidant in the treatment of oxidative stress related disorders. Yet, its potential clinical implementation has been greatly hampered by its poor water solubility and lack of reliable tracking methodologies/processes and hence poor absorption, distribution, and targeted delivery. The water solubility and surface engineering of a drug with biocompatible motifs are fundamental to pharmaceutical products and precision medicine. Here, we report an engineered water-soluble, biocompatible, trackable nanoceria with enriched antioxidant activity to scavenge intracellular reactive oxygen species (ROS). Experimental studies with in vitro and in vivo models demonstrated that this antioxidant is autoregenerative and more active in inhibiting laser-induced choroidal neovascularization by decreasing ROS-induced pro-angiogenic vascular endothelial growth factor (VEGF) expression, cumulative oxidative damage, and recruitment of endothelial precursor cells without exhibiting any toxicity. This advanced formulation may offer a superior therapeutic effect to deal with oxidative stress induced pathogeneses, such as AMD.

The demand for effective eye therapies is driving the development of injectable hydrogels as new medical devices for controlled delivery and filling purposes. This article introduces the properties of injectable hydrogels and summarizes their versatile application in the treatment of ophthalmic diseases, including age-related macular degeneration, cataracts, diabetic retinopathy, glaucoma, and intraocular cancers. A number of injectable hydrogels are approved by FDA as surgery sealants, tissue adhesives, and are now being investigated as a vitreous humor substitute. Research on hydrogels for drug, factor, nanoparticle, and stem cell delivery is still under pre-clinical investigation or in clinical trials. Although substantial progress has been achieved using injectable hydrogels, some challenging issues must still be overcome before they can be effectively used in medical practice.

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Retinoblastoma (RB) is a pediatric retinal tumor that overexpresses the ganglioside GD2. Although it is treatable in patients with early diagnosis, patients may lose one or two eyes. We generated GD2-specific chimeric antigen receptor T lymphocytes (GD2.CAR-Ts) and locally delivered them to mice with an in-situ grafting RB. When used in combination with the local release of interleukin (IL)-15 and an injectable hydrogel, we showed that GD2.CAR-Ts successfully eliminate RB tumor cells without impairment of the mouse vision.

Mutations in the rhodopsin gene cause retinal degeneration and clinical phenotypes including retinitis pigmentosa (RP) and congenital stationary night blindness. Effective gene therapies have been difficult to develop, however, because generating precise levels of rhodopsin expression is critical; overexpression causes toxicity, and underexpression would result in incomplete rescue. Current gene delivery strategies routinely use cDNA-based vectors for gene targeting; however, inclusion of noncoding components of genomic DNA (gDNA) such as introns may help promote more endogenous regulation of gene expression. Here we test the hypothesis that inclusion of genomic sequences from the rhodopsin gene can improve the efficacy of rhodopsin gene therapy in the rhodopsin knockout (RKO) mouse model of RP. We utilize our compacted DNA nanoparticles (NPs), which have the ability to transfer larger and more complex genetic constructs, to deliver murine rhodopsin cDNA or gDNA. We show functional and structural improvements in RKO eyes for up to 8 months after NP-mediated gDNA but not cDNA delivery. Importantly, in addition to improvements in rod function, we observe significant preservation of cone function at time points when cones in the RKO model are degenerated. These results suggest that inclusion of native expression elements, such as introns, can significantly enhance gene expression and therapeutic efficacy and may become an essential option in the array of available gene delivery tools.

Aim To evaluate the safety of compacted DNA nanoparticles (NPs) in retinal pigment epithelial (RPE) cells. Materials & Methods Enhanced GFP expression cassettes controlled by the RPE-specific vitelloform macular dystrophy promoter were constructed with and without a bacterial backbone and compacted into NPs formulated with polyethylene glycol-substituted lysine 30-mers. Single or double subretinal injections were administered in adult BALB/c mice. Expression levels of enhanced GFP, proinflammatory cytokines and neutrophil/macrophage mediators, and retinal function by electroretinogram were evaluated at different time-points postinjection. Results Immunohistochemistry and real-time PCR demonstrated that NPs specifically transfect RPE cells at a higher efficiency than naked DNA and similar results were observed after the second injection. At 6 h postinjections, a transient inflammatory response was observed in all cohorts, including saline, indicating an adverse effect to the injection procedure. Subsequently, no inflammation was detected in all experimental groups. Conclusion This study demonstrates the safety and efficacy of NP-mediated RPE gene transfer therapy following multiple subretinal administrations.