DNA nanoparticle-mediated ABCA4 delivery rescues Stargardt dystrophy in mice
Zongchao Han, … , Mark J. Cooper, Muna I. Naash
Zongchao Han, … , Mark J. Cooper, Muna I. Naash
Published August 13, 2012
Citation Information: J Clin Invest. 2012;122(9):3221-3226. https://doi.org/10.1172/JCI64833.
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Brief Report Genetics

DNA nanoparticle-mediated ABCA4 delivery rescues Stargardt dystrophy in mice

Abstract

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.

Authors

Zongchao Han, Shannon M. Conley, Rasha S. Makkia, Mark J. Cooper, Muna I. Naash

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Figure 1

NP-mediated ABCA4 gene delivery induces persistent gene expression throughout the retina in Abca4–/– mice.

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NP-mediated ABCA4 gene delivery induces persistent gene expression throu...
(A) ABCA4 mRNA levels were assessed by qRT-PCR and normalized to endogenous β-actin. Saline-injected and uninjected eyes were used as negative controls. (B) Western blots and quantitation thereof (C). Shown are 3 representative eyes at each time point/group (labels 1–3) injected with either WT or mutant NPs. (n = 4–6 eyes/group for A–C). Protein levels were normalized to β-actin and expressed as a percentage of levels found in uninjected WT mice. Results for WT and mu-NP treatment in A and C were analyzed by 2-way ANOVA with Bonferroni’s post-hoc comparisons. (D and E) Retinal cryosections at 8 months PI were colabeled for ABCA4 (green), S-opsin (red) with DAPI (epifluorescent images/bright field, D; single planes of confocal stacks, E). Arrows, cones expressing ABCA4; arrowheads, cones not expressing ABCA4. (F) At 8 months PI, cryosections were collected approximately every 200 μm throughout the eye along the nasal-temporal plane and were labeled with antibodies against ABCA4 (green). In each section, adjacent ×40 fields (∼200 μm across) were graded for level of expression by a blinded observer. Schematics depict distribution of transferred ABCA4 throughout the eye. Scale bars: 20 μm (D); 10 μm (E). OS, outer segment; INL, inner nuclear layer; S, superior; I, inferior; T, temporal; N, nasal.