This is a competitive renewal of R01EY024280, ?Developing Efficient AAV Vectors for Photoreceptor Targeting via the Vitreous?. Note that, due to advances made during the initial funding period, and our improved understanding of challenges in the field, our title has been changed to ?Engineering AAV for safe and efficient gene delivery to the human retina? to more broadly encompass our goals. FDA approval of an Adeno associated virus (AAV)- based gene therapy for RPE65-Leber congenital amaurosis (LCA2) solidified gene therapy?s place in current medical practice. However, injection of vector under the fovea of some patients led to central retinal thinning and loss of visual acuity. Similar decreases in retinal thickness were also observed in Choroideremia clinical trials. In more severe conditions, like X-linked Retinoschisis (XLRS), there is concern that subretinal injection (SRI) will further damage patient retinas. Since most inherited retinal diseases (IRDs) are caused by mutations in photoreceptor (PR)- and retinal pigment epithelial (RPE)- specific genes, development of gene therapies that more safely and efficiently target these cells remains a significant, unmet need. Targeting foveal cones is especially important, as they are responsible for acute, daylight vision. During the initial funding period, we developed AAV capsids capable of efficient retinal transduction following intravitreal injection (IVI) in primate. The inner limiting membrane (ILM) is the major barrier to AAV transduction via this this route. However, results from clinical trials utilizing IVI AAVs that show dose-limiting inflammation, and neutralization of the AAV capsid by pre-existing antibodies (NAbs) implicate the host immune system as a more immediate ?barrier? to clinical translation. The eye?s ?immune-privilege? has perhaps led to an under appreciation of the immune system?s role in shaping the outcome of intra-ocularly delivered AAVs. Naturally occurring antibodies to capsids capable of transducing retina via the vitreous (i.e. AAV2) are prevalent in up to 70% of humans. As such, a large percentage of patients will not meet inclusion criteria for emerging therapies. Here we propose experiments, based on strong preliminary data, to overcome these barriers. The majority of work will be performed in primates (macaque) as these barriers can only be recapitulated in intact eyes of animals with ocular characteristics and immune systems similar to humans.
In Aim 1, we will enhance transduction and safety of intravitreally delivered AAVs by engineering the capsid and genome to avoid immune recognition.
In Aim 2, we will enhance retinal transduction by subILM delivery of AAVs to enable efficient and specific transduction of inner and outer retina.
In Aim 3, we will enhance transduction by subretinally delivered AAVs that spread laterally beyond the injection site. Vectors and methods investigated in this proposal will have an immediate impact on planned clinical trials to address inherited retinal diseases as well as non-orphan indications such as AMD. Development of these tools by academia (rather than industry) will ensure the availability of shared resources with the broader scientific community.

Public Health Relevance

The overall goal of this proposal is to develop novel Adeno associated viral (AAV) vectors and complementary delivery methods that overcome the hurdles to safe and efficient retinal gene delivery. The ability to target foveal cones is especially significant because this is the area of the retina responsible for acute, daylight vision. The majority of our work will be performed in primates (macaque) as these hurdles are faithfully recapitulated only in the intact eyes of animals with a fully functioning immune system, and ocular characteristics similar to humans.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
2R01EY024280-06
Application #
9816421
Study Section
Diseases and Pathophysiology of the Visual System Study Section (DPVS)
Program Officer
Shen, Grace L
Project Start
2014-06-01
Project End
2024-05-31
Budget Start
2019-09-01
Budget End
2020-05-31
Support Year
6
Fiscal Year
2019
Total Cost
Indirect Cost
Name
University of Florida
Department
Ophthalmology
Type
Schools of Medicine
DUNS #
969663814
City
Gainesville
State
FL
Country
United States
Zip Code
32611
Kanaan, Nicholas M; Sellnow, Rhyomi C; Boye, Sanford L et al. (2017) Rationally Engineered AAV Capsids Improve Transduction and Volumetric Spread in the CNS. Mol Ther Nucleic Acids 8:184-197
Beltran, William A; Cideciyan, Artur V; Boye, Shannon E et al. (2017) Optimization of Retinal Gene Therapy for X-Linked Retinitis Pigmentosa Due to RPGR Mutations. Mol Ther 25:1866-1880
Cho, Jung-Hwa; Swanson, Carter J; Chen, Jeannie et al. (2017) The GCaMP-R Family of Genetically Encoded Ratiometric Calcium Indicators. ACS Chem Biol 12:1066-1074
Choudhury, Shreyasi; Strang, Christianne E; Alexander, John J et al. (2016) Novel Methodology for Creating Macaque Retinas with Sortable Photoreceptors and Ganglion Cells. Front Neurosci 10:551
Xie, Keqiang; Colgan, Lesley A; Dao, Maria T et al. (2016) NF1 Is a Direct G Protein Effector Essential for Opioid Signaling to Ras in the Striatum. Curr Biol 26:2992-3003
Boyd, R F; Sledge, D G; Boye, S L et al. (2016) Photoreceptor-targeted gene delivery using intravitreally administered AAV vectors in dogs. Gene Ther 23:223-30
Boye, Shannon E; Alexander, John J; Witherspoon, C Douglas et al. (2016) Highly Efficient Delivery of Adeno-Associated Viral Vectors to the Primate Retina. Hum Gene Ther 27:580-97
Boye, Sanford L; Bennett, Antonette; Scalabrino, Miranda L et al. (2016) Impact of Heparan Sulfate Binding on Transduction of Retina by Recombinant Adeno-Associated Virus Vectors. J Virol 90:4215-4231
Boyd, R F; Boye, S L; Conlon, T J et al. (2016) Reduced retinal transduction and enhanced transgene-directed immunogenicity with intravitreal delivery of rAAV following posterior vitrectomy in dogs. Gene Ther 23:548-56
Ildefonso, Cristhian J; Jaime, Henrique; Brown, Emily E et al. (2016) Targeting the Nrf2 Signaling Pathway in the Retina With a Gene-Delivered Secretable and Cell-Penetrating Peptide. Invest Ophthalmol Vis Sci 57:372-86

Showing the most recent 10 out of 17 publications