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Jo A, Deniz S, Cherian S, Xu J, Futagi D, DeVries SH, Zhu Y. Modular interneuron circuits control motion sensitivity in the mouse retina. Nat Commun 2023; 14:7746. [PMID: 38008788 PMCID: PMC10679153 DOI: 10.1038/s41467-023-43382-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 11/08/2023] [Indexed: 11/28/2023] Open
Abstract
Neural computations arise from highly precise connections between specific types of neurons. Retinal ganglion cells (RGCs) with similar stratification patterns are positioned to receive similar inputs but often display different response properties. In this study, we used intersectional mouse genetics to achieve single-cell type labeling and identified an object motion sensitive (OMS) AC type, COMS-AC(counter-OMS AC). Optogenetic stimulation revealed that COMS-AC makes glycinergic synapses with the OMS-insensitive HD2p-RGC, while chemogenetic inactivation showed that COMS-AC provides inhibitory control to HD2p-RGC during local motion. This local inhibition, combined with the inhibitory drive from TH2-AC during global motion, explains the OMS-insensitive feature of HD2p-RGC. In contrast, COMS-AC fails to make synapses with W3(UHD)-RGC, allowing it to exhibit OMS under the control of VGlut3-AC and TH2-AC. These findings reveal modular interneuron circuits that endow structurally similar RGC types with different responses and present a mechanism for redundancy-reduction in the retina to expand coding capacity.
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Affiliation(s)
- Andrew Jo
- Departments of Ophthalmology and Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Sercan Deniz
- Departments of Ophthalmology and Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Suraj Cherian
- Departments of Ophthalmology and Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Jian Xu
- Departments of Ophthalmology and Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Daiki Futagi
- Departments of Ophthalmology and Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Steven H DeVries
- Departments of Ophthalmology and Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Yongling Zhu
- Departments of Ophthalmology and Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
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Jo A, Deniz S, Xu J, Duvoisin RM, DeVries SH, Zhu Y. A sign-inverted receptive field of inhibitory interneurons provides a pathway for ON-OFF interactions in the retina. Nat Commun 2023; 14:5937. [PMID: 37741839 PMCID: PMC10517963 DOI: 10.1038/s41467-023-41638-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 09/11/2023] [Indexed: 09/25/2023] Open
Abstract
A fundamental organizing plan of the retina is that visual information is divided into ON and OFF streams that are processed in separate layers. This functional dichotomy originates in the ON and OFF bipolar cells, which then make excitatory glutamatergic synapses onto amacrine and ganglion cells in the inner plexiform layer. We have identified an amacrine cell (AC), the sign-inverting (SI) AC, that challenges this fundamental plan. The glycinergic, ON-stratifying SI-AC has OFF light responses. In opposition to the classical wiring diagrams, it receives inhibitory inputs from glutamatergic ON bipolar cells at mGluR8 synapses, and excitatory inputs from an OFF wide-field AC at electrical synapses. This "inhibitory ON center - excitatory OFF surround" receptive-field of the SI-AC allows it to use monostratified dendrites to conduct crossover inhibition and push-pull activation to enhance light detection by ACs and RGCs in the dark and feature discrimination in the light.
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Affiliation(s)
- Andrew Jo
- Departments of Ophthalmology and Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Sercan Deniz
- Departments of Ophthalmology and Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Jian Xu
- Departments of Ophthalmology and Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Robert M Duvoisin
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Steven H DeVries
- Departments of Ophthalmology and Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
| | - Yongling Zhu
- Departments of Ophthalmology and Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
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Amato A, Arrigo A, Aragona E, Manitto MP, Saladino A, Bandello F, Battaglia Parodi M. Gene Therapy in Inherited Retinal Diseases: An Update on Current State of the Art. Front Med (Lausanne) 2021; 8:750586. [PMID: 34722588 PMCID: PMC8553993 DOI: 10.3389/fmed.2021.750586] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/20/2021] [Indexed: 12/11/2022] Open
Abstract
Background: Gene therapy cannot be yet considered a far perspective, but a tangible therapeutic option in the field of retinal diseases. Although still confined in experimental settings, the preliminary results are promising and provide an overall scenario suggesting that we are not so far from the application of gene therapy in clinical settings. The main aim of this review is to provide a complete and updated overview of the current state of the art and of the future perspectives of gene therapy applied on retinal diseases. Methods: We carefully revised the entire literature to report all the relevant findings related to the experimental procedures and the future scenarios of gene therapy applied in retinal diseases. A clinical background and a detailed description of the genetic features of each retinal disease included are also reported. Results: The current literature strongly support the hope of gene therapy options developed for retinal diseases. Although being considered in advanced stages of investigation for some retinal diseases, such as choroideremia (CHM), retinitis pigmentosa (RP), and Leber's congenital amaurosis (LCA), gene therapy is still quite far from a tangible application in clinical practice for other retinal diseases. Conclusions: Gene therapy is an extremely promising therapeutic tool for retinal diseases. The experimental data reported in this review offer a strong hope that gene therapy will be effectively available in clinical practice in the next years.
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Affiliation(s)
- Alessia Amato
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Alessandro Arrigo
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Emanuela Aragona
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Maria Pia Manitto
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Andrea Saladino
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Francesco Bandello
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
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Turkalj B, Quallich D, Bessert DA, Kramer AC, Cook TA, Thummel R. Development and characterization of a chronic photoreceptor degeneration model in adult zebrafish that does not trigger a regenerative response. Exp Eye Res 2021; 209:108630. [PMID: 34029596 DOI: 10.1016/j.exer.2021.108630] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/05/2021] [Accepted: 05/16/2021] [Indexed: 11/29/2022]
Abstract
Zebrafish (Danio rerio) have become a highly-utilized model system in the field of regenerative biology because of their endogenous ability to regenerate many tissues and organs, including the retina. The vast majority of previous research on retinal regeneration in adult zebrafish utilizes acute methodologies for retinal damage. Acute retinal cell death triggers a reactive gliosis response of Müller glia (MG), the resident macroglia of the retina. In addition, each activated MG undergoes asymmetric cell division to produce a neuronal progenitor, which continues to divide and ultimately gives rise to new retinal neurons. Studies using these approaches have uncovered many crucial mechanisms by which MG respond to acute damage. However, they may not adequately mimic the chronic neuronal degeneration observed in many human retinal degenerative diseases. The current study aimed to develop a new long-term, chronic photoreceptor damage and degeneration model in adult zebrafish. Comparing the subsequent cellular responses to that of the commonly-used acute high-intensity model, we found that low, continuous light exposure damaged the outer segments of both rod and cone photoreceptors, but did not result in significant apoptotic cell death, MG gliosis, or MG cell-cycle re-entry. Instead, chronic light nearly completely truncated photoreceptor outer segments and resulted in a recruitment of microglia to the area. Together, these studies present a chronic photoreceptor model that can be performed in a relatively short time frame (21 days), that may lend insight into the cellular events underlying non-regenerative photoreceptor degeneration observed in other model systems.
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Affiliation(s)
- Brooke Turkalj
- Wayne State University School of Medicine, Department of Ophthalmology, Visual and Anatomical Sciences, Detroit, MI, USA.
| | - Danielle Quallich
- Wayne State University School of Medicine, Department of Ophthalmology, Visual and Anatomical Sciences, Detroit, MI, USA.
| | - Denise A Bessert
- Wayne State University School of Medicine, Department of Ophthalmology, Visual and Anatomical Sciences, Detroit, MI, USA.
| | - Ashley C Kramer
- Wayne State University School of Medicine, Department of Ophthalmology, Visual and Anatomical Sciences, Detroit, MI, USA.
| | - Tiffany A Cook
- Wayne State University School of Medicine, Department of Ophthalmology, Visual and Anatomical Sciences, Detroit, MI, USA; Wayne State University School of Medicine, Center for Molecular Medicine and Genetics, Detroit, MI, USA.
| | - Ryan Thummel
- Wayne State University School of Medicine, Department of Ophthalmology, Visual and Anatomical Sciences, Detroit, MI, USA.
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Effects of Altering HSPG Binding and Capsid Hydrophilicity on Retinal Transduction by AAV. J Virol 2021; 95:JVI.02440-20. [PMID: 33658343 PMCID: PMC8139652 DOI: 10.1128/jvi.02440-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Adeno-associated viruses (AAVs) have recently emerged as the leading vector for retinal gene therapy. However, AAV vectors which are capable of achieving clinically relevant levels of transgene expression and widespread retinal transduction are still an unmet need. Using rationally designed AAV2-based capsid variants, we investigate the role of capsid hydrophilicity and hydrophobicity as it relates to retinal transduction. We show that hydrophilic, single amino acid (aa) mutations (V387R, W502H, E530K, L583R) in AAV2 negatively impact retinal transduction when heparan sulfate proteoglycan (HSPG) binding remains intact. Conversely, addition of hydrophobic point mutations to an HSPG binding deficient capsid (AAV2ΔHS) lead to increased retinal transduction in both mouse and macaque. Our top performing vector, AAV2(4pMut)ΔHS, achieved robust rod and cone photoreceptor (PR) transduction in macaque, especially in the fovea, and demonstrates the ability to spread laterally beyond the borders of the subretinal injection (SRI) bleb. This study both evaluates biophysical properties of AAV capsids that influence retinal transduction, and assesses the transduction and tropism of a novel capsid variant in a clinically relevant animal model.ImportanceRationally guided engineering of AAV capsids aims to create new generations of vectors with enhanced potential for human gene therapy. By applying rational design principles to AAV2-based capsids, we evaluated the influence of hydrophilic and hydrophobic amino acid (aa) mutations on retinal transduction as it relates to vector administration route. Through this approach we identified a largely deleterious relationship between hydrophilic aa mutations and canonical HSPG binding by AAV2-based capsids. Conversely, the inclusion of hydrophobic aa substitutions on a HSPG binding deficient capsid (AAV2ΔHS), generated a vector capable of robust rod and cone photoreceptor (PR) transduction. This vector AAV2(4pMut)ΔHS also demonstrates a remarkable ability to spread laterally beyond the initial subretinal injection (SRI) bleb, making it an ideal candidate for the treatment of retinal diseases which require a large area of transduction.
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Luo DG, Silverman D, Frederiksen R, Adhikari R, Cao LH, Oatis JE, Kono M, Cornwall MC, Yau KW. Apo-Opsin and Its Dark Constitutive Activity across Retinal Cone Subtypes. Curr Biol 2020; 30:4921-4931.e5. [PMID: 33065015 PMCID: PMC8561704 DOI: 10.1016/j.cub.2020.09.062] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 08/08/2020] [Accepted: 09/18/2020] [Indexed: 11/22/2022]
Abstract
Retinal rod and cone photoreceptors mediate vision in dim and bright light, respectively, by transducing absorbed photons into neural electrical signals. Their phototransduction mechanisms are essentially identical. However, one difference is that, whereas a rod visual pigment remains stable in darkness, a cone pigment has some tendency to dissociate spontaneously into apo-opsin and retinal (the chromophore) without isomerization. This cone-pigment property is long known but has mostly been overlooked. Importantly, because apo-opsin has weak constitutive activity, it triggers transduction to produce electrical noise even in darkness. Currently, the precise dark apo-opsin contents across cone subtypes are mostly unknown, as are their dark activities. We report here a study of goldfish red (L), green (M), and blue (S) cones, finding with microspectrophotometry widely different apo-opsin percentages in darkness, being ∼30% in L cones, ∼3% in M cones, and negligible in S cones. L and M cones also had higher dark apo-opsin noise than holo-pigment thermal isomerization activity. As such, given the most likely low signal amplification at the pigment-to-transducin/phosphodiesterase phototransduction step, especially in L cones, apo-opsin noise may not be easily distinguishable from light responses and thus may affect cone vision near threshold.
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Affiliation(s)
- Dong-Gen Luo
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Daniel Silverman
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Biochemistry, Cellular and Molecular Biology Graduate Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Rikard Frederiksen
- Jules Stein Eye Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Rajan Adhikari
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA
| | - Li-Hui Cao
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - John E Oatis
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Masahiro Kono
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - M Carter Cornwall
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA
| | - King-Wai Yau
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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7
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Padhy SK, Takkar B, Narayanan R, Venkatesh P, Jalali S. Voretigene Neparvovec and Gene Therapy for Leber's Congenital Amaurosis: Review of Evidence to Date. APPLICATION OF CLINICAL GENETICS 2020; 13:179-208. [PMID: 33268999 PMCID: PMC7701157 DOI: 10.2147/tacg.s230720] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 11/06/2020] [Indexed: 12/13/2022]
Abstract
Gene therapy has now evolved as the upcoming modality for management of many disorders, both inheritable and non-inheritable. Knowledge of genetics pertaining to a disease has therefore become paramount for physicians across most specialities. Inheritable retinal dystrophies (IRDs) are notorious for progressive and relentless vision loss, frequently culminating in complete blindness in both eyes. Leber’s congenital amaurosis (LCA) is a typical example of an IRD that manifests very early in childhood. Research in gene therapy has led to the development and approval of voretigene neparvovec (VN) for use in patients of LCA with a deficient biallelic RPE65 gene. The procedure involves delivery of a recombinant virus vector that carries the RPE65 gene in the subretinal space. This comprehensive review reports the evidence thus far in support of gene therapy for LCA. We explore and compare the various gene targets including but not limited to RPE65, and discuss the choice of vector and method for ocular delivery. The review details the evolution of gene therapy with VN in a phased manner, concluding with the challenges that lie ahead for its translation for use in communities that differ much both genetically and economically.
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Affiliation(s)
- Srikanta Kumar Padhy
- Vitreoretina and Uveitis Services, L V Prasad Eye Institute, Mithu Tulsi Chanrai Campus, Bhubaneswar, India
| | - Brijesh Takkar
- Srimati Kanuri Santhamma Center for Vitreoretinal Diseases, Kallam Anji Reddy Campus, L.V. Prasad Eye Institute, Hyderabad, India.,Center of Excellence for Rare Eye Diseases, Kallam Anji Reddy Campus, L V Prasad Eye Institute, Hyderabad, India
| | - Raja Narayanan
- Srimati Kanuri Santhamma Center for Vitreoretinal Diseases, Kallam Anji Reddy Campus, L.V. Prasad Eye Institute, Hyderabad, India
| | - Pradeep Venkatesh
- Dr RP Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Subhadra Jalali
- Srimati Kanuri Santhamma Center for Vitreoretinal Diseases, Kallam Anji Reddy Campus, L.V. Prasad Eye Institute, Hyderabad, India.,Jasti V. Ramanamma Childrens' Eye Care Centre, Kallam Anji Reddy Campus, L V Prasad Eye Institute, Hyderabad, India
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Boye SL, Choudhury S, Crosson S, Di Pasquale G, Afione S, Mellen R, Makal V, Calabro KR, Fajardo D, Peterson J, Zhang H, Leahy MT, Jennings CK, Chiorini JA, Boyd RF, Boye SE. Novel AAV44.9-Based Vectors Display Exceptional Characteristics for Retinal Gene Therapy. Mol Ther 2020; 28:1464-1478. [PMID: 32304666 PMCID: PMC7264435 DOI: 10.1016/j.ymthe.2020.04.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/28/2020] [Accepted: 04/02/2020] [Indexed: 01/13/2023] Open
Abstract
The majority of inherited retinal diseases (IRDs) are caused by mutations in genes expressed in photoreceptors (PRs). The ideal vector to address these conditions is one that transduces PRs in large areas of retina with the smallest volume/lowest titer possible, and efficiently transduces foveal cones, the cells responsible for acute, daylight vision that are often the only remaining area of functional retina in IRDs. The purpose of our study was to evaluate the retinal tropism and potency of a novel capsid, AAV44.9, and rationally designed derivatives thereof. We found that AAV44.9 and AAV44.9(E531D) transduced retinas of subretinally injected (SRI) mice with higher efficiency than did benchmark AAV5- and AAV8-based vectors. In macaques, highly efficient cone and rod transduction was observed following submacular and peripheral SRI. AAV44.9- and AAV44.9(E531D)-mediated GFP fluorescence extended laterally well beyond SRI bleb margins. Notably, extrafoveal injection (i.e., fovea not detached during surgery) led to transduction of up to 98% of foveal cones. AAV44.9(E531D) efficiently transduced parafoveal and perifoveal cones, whereas AAV44.9 did not. AAV44.9(E531D) was also capable of restoring retinal function to a mouse model of IRD. These novel capsids will be useful for addressing IRDs that would benefit from an expansive treatment area.
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Affiliation(s)
- Sanford L Boye
- Department of Pediatrics and the Powell Gene Therapy Center, University of Florida, Gainesville, FL, USA
| | - Shreyasi Choudhury
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Sean Crosson
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Giovanni Di Pasquale
- Adeno-Associated Virus Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Sandra Afione
- Adeno-Associated Virus Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Russell Mellen
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Victoria Makal
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Kaitlyn R Calabro
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Diego Fajardo
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA
| | - James Peterson
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Hangning Zhang
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Matthew T Leahy
- Ophthalmology Services, Charles River Laboratories, Mattawan, MI, USA
| | - Colin K Jennings
- Ophthalmology Services, Charles River Laboratories, Mattawan, MI, USA
| | - John A Chiorini
- Adeno-Associated Virus Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Ryan F Boyd
- Ophthalmology Services, Charles River Laboratories, Mattawan, MI, USA
| | - Shannon E Boye
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA.
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Miranda CJ, Fernandez N, Kamel N, Turner D, Benzenhafer D, Bolch SN, Andring JT, McKenna R, Smith WC. An arrestin-1 surface opposite of its interface with photoactivated rhodopsin engages with enolase-1. J Biol Chem 2020; 295:6498-6508. [PMID: 32238431 PMCID: PMC7212649 DOI: 10.1074/jbc.ra120.013043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/30/2020] [Indexed: 01/14/2023] Open
Abstract
Arrestin-1 is the arrestin family member responsible for inactivation of the G protein–coupled receptor rhodopsin in photoreceptors. Arrestin-1 is also well-known to interact with additional protein partners and to affect other signaling cascades beyond phototransduction. In this study, we investigated one of these alternative arrestin-1 binding partners, the glycolysis enzyme enolase-1, to map the molecular contact sites between these two proteins and investigate how the binding of arrestin-1 affects the catalytic activity of enolase-1. Using fluorescence quench protection of strategically placed fluorophores on the arrestin-1 surface, we observed that arrestin-1 primarily engages enolase-1 along a surface that is opposite of the side of arrestin-1 that binds photoactivated rhodopsin. Using this information, we developed a molecular model of the arrestin-1–enolase-1 complex, which was validated by targeted substitutions of charge-pair interactions. Finally, we identified the likely source of arrestin's modulation of enolase-1 catalysis, showing that selective substitution of two amino acids in arrestin-1 can completely remove its effect on enolase-1 activity while still remaining bound to enolase-1. These findings open up opportunities for examining the functional effects of arrestin-1 on enolase-1 activity in photoreceptors and their surrounding cells.
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Affiliation(s)
| | - Nicole Fernandez
- Department of Ophthalmology, University of Florida, Gainesville, Florida 32610
| | - Nader Kamel
- Department of Ophthalmology, University of Florida, Gainesville, Florida 32610
| | - Daniel Turner
- Department of Ophthalmology, University of Florida, Gainesville, Florida 32610
| | - Del Benzenhafer
- Department of Ophthalmology, University of Florida, Gainesville, Florida 32610
| | - Susan N Bolch
- Department of Ophthalmology, University of Florida, Gainesville, Florida 32610
| | - Jacob T Andring
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - W Clay Smith
- Department of Ophthalmology, University of Florida, Gainesville, Florida 32610
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10
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Bouzia Z, Georgiou M, Hull S, Robson AG, Fujinami K, Rotsos T, Pontikos N, Arno G, Webster AR, Hardcastle AJ, Fiorentino A, Michaelides M. GUCY2D-Associated Leber Congenital Amaurosis: A Retrospective Natural History Study in Preparation for Trials of Novel Therapies. Am J Ophthalmol 2020; 210:59-70. [PMID: 31704230 PMCID: PMC7013380 DOI: 10.1016/j.ajo.2019.10.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 10/21/2019] [Accepted: 10/23/2019] [Indexed: 10/25/2022]
Abstract
PURPOSE To describe the natural history of Leber congenital amaurosis (LCA) associated with GUCY2D variants (GUCY2D-LCA) in a cohort of children and adults, in preparation for trials of novel therapies. DESIGN Retrospective case series. METHODS Participants: Patients with GUCY2D-LCA at a single referral center. PROCEDURES Review of clinical notes, retinal imaging including fundus autofluorescence (FAF) and optical coherence tomography (OCT), electroretinography (ERG), and molecular genetic testing. MAIN OUTCOME MEASURES Demographic data, symptoms at presentation, visual acuity, evidence of progression, OCT and FAF findings, ERG assessment, and molecular genetics. RESULTS Twenty-one subjects with GUCY2D-LCA were included, with a mean follow-up ± standard deviation (SD) of 10 ± 11.85 years. Marked reduction in visual acuity (VA) and nystagmus was documented in all patients within the first 3 years of life. Fifty-seven percent (n = 12) exhibited photophobia and 38% (n = 8) had nyctalopia. VA was worse than hand motion in 71% of the patients (n = 15). Longitudinal assessment of VA showed stability in all patients, except 1 patient who experienced deterioration over a follow-up of 44 years. Hyperopia was reported in 13 of the 17 subjects (71%) with available refraction data. Eighteen subjects had either normal fundus appearance (n = 14) or a blond fundus (n = 3), while only 4 of the eldest subjects had mild retinal pigment epithelium (RPE) atrophy (mean, 49 years; range 40-54 years). OCT data were available for 11 subjects and 4 different grades of ellipsoid zone (EZ) integrity were identified: (1) continuous/intact EZ (n = 6), (2) focally disrupted EZ (n = 2), (3) focally disrupted with RPE changes (n = 2), and (4) diffuse EZ disruption with RPE changes (n = 1). All examined subjects had stable OCT findings over the long follow-up period. Full-field ERGs showed evidence of a severe cone-rod dystrophy in 5 of 6 patients and undetectable ERGs in 1 subject. Novel genotype-phenotype correlations are also reported. CONCLUSION GUCY2D-LCA is a severe early-onset retinal dystrophy associated with very poor VA from birth. Despite the severely affected photoreceptor function, the relatively preserved photoreceptor structure based on EZ integrity until late in the disease in the majority of subjects suggests a wide therapeutic window for gene therapy trials.
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11
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Vancura P, Csicsely E, Leiser A, Iuvone PM, Spessert R. Rhythmic Regulation of Photoreceptor and RPE Genes Important for Vision and Genetically Associated With Severe Retinal Diseases. Invest Ophthalmol Vis Sci 2019; 59:3789-3799. [PMID: 30073352 PMCID: PMC6071477 DOI: 10.1167/iovs.18-24558] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The aim of the present study was to identify candidate genes for mediating daily adjustment of vision. Methods Genes important for vision and genetically associated with severe retinal diseases were tested for 24-hour rhythms in transcript levels in neuronal retina, microdissected photoreceptors, photoreceptor-related pinealocytes, and retinal pigment epithelium-choroid (RPE-choroid) complex by using quantitative PCR. Results Photoreceptors of wildtype mice display circadian clock-dependent regulation of visual arrestins (Arr1, Arr4) and the visual cycle gene Rdh12, whereas cells of the RPE-choroid exhibit light-dependent regulation of the visual cycle key genes Lrat, Rpe65, and Rdh5. Clock-driven rhythmicity of Arr1, Arr4, and Rdh12 was observed also in rat pinealocytes, to persist in a mouse model of diabetic retinopathy (db/db) and, in the case of Arr1, to be abolished in retinae of mice deficient for dopamine D4 receptors. Therefore, the expression rhythms appear to be evolutionary conserved, to be unaffected in diabetic retinopathy, and, for Arr1, to require dopamine signaling via dopamine D4 receptors. Conclusions The data of the present study suggest that daily adjustment of retinal function combines clock-dependent regulation of genes responsible for phototransduction termination (Arr1, Arr4) and detoxification (Rdh12) in photoreceptors with light-dependent regulation of genes responsible for retinoid recycling (Lrat, Rpe65, and Rdh5) in RPE. Furthermore, they indicate circadian and light-dependent regulation of genes genetically associated with severe retinal diseases.
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Affiliation(s)
- Patrick Vancura
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Erika Csicsely
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Annalisa Leiser
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - P Michael Iuvone
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Rainer Spessert
- Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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12
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Ying G, Frederick JM, Baehr W. Deletion of both centrin 2 (CETN2) and CETN3 destabilizes the distal connecting cilium of mouse photoreceptors. J Biol Chem 2019; 294:3957-3973. [PMID: 30647131 DOI: 10.1074/jbc.ra118.006371] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 01/09/2019] [Indexed: 02/03/2023] Open
Abstract
Centrins (CETN1-4) are ubiquitous and conserved EF-hand-family Ca2+-binding proteins associated with the centrosome, basal body, and transition zone. Deletion of CETN1 or CETN2 in mice causes male infertility or dysosmia, respectively, without affecting photoreceptor function. However, it remains unclear to what extent centrins are redundant with each other in photoreceptors. Here, to explore centrin redundancy, we generated Cetn3 GT/GT single-knockout and Cetn2 -/-;Cetn3 GT/GT double-knockout mice. Whereas the Cetn3 deletion alone did not affect photoreceptor function, simultaneous ablation of Cetn2 and Cetn3 resulted in attenuated scotopic and photopic electroretinography (ERG) responses in mice at 3 months of age, with nearly complete retina degeneration at 1 year. Removal of CETN2 and CETN3 activity from the lumen of the connecting cilium (CC) destabilized the photoreceptor axoneme and reduced the CC length as early as postnatal day 22 (P22). In Cetn2 -/-;Cetn3 GT/GT double-knockout mice, spermatogenesis-associated 7 (SPATA7), a key organizer of the photoreceptor-specific distal CC, was depleted gradually, and CETN1 was condensed to the mid-segment of the CC. Ultrastructural analysis revealed that in this double knockout, the axoneme of the CC expanded radially at the distal end, with vertically misaligned outer segment discs and membrane whorls. These observations suggest that CETN2 and CETN3 cooperate in stabilizing the CC/axoneme structure.
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Affiliation(s)
- Guoxin Ying
- From the Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah 84132,
| | - Jeanne M Frederick
- From the Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah 84132
| | - Wolfgang Baehr
- From the Department of Ophthalmology, University of Utah Health Science Center, Salt Lake City, Utah 84132, .,the Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah 84112, and.,the Department of Biology, University of Utah, Salt Lake City, Utah 84132
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13
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Deng WT, Kolandaivelu S, Dinculescu A, Li J, Zhu P, Chiodo VA, Ramamurthy V, Hauswirth WW. Cone Phosphodiesterase-6γ' Subunit Augments Cone PDE6 Holoenzyme Assembly and Stability in a Mouse Model Lacking Both Rod and Cone PDE6 Catalytic Subunits. Front Mol Neurosci 2018; 11:233. [PMID: 30038560 PMCID: PMC6046437 DOI: 10.3389/fnmol.2018.00233] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 06/13/2018] [Indexed: 11/13/2022] Open
Abstract
Rod and cone phosphodiesterase 6 (PDE6) are key effector enzymes of the vertebrate phototransduction pathway. Rod PDE6 consists of two catalytic subunits PDE6α and PDE6β and two identical inhibitory PDE6γ subunits, while cone PDE6 is composed of two identical PDE6α’ catalytic subunits and two identical cone-specific PDE6γ’ inhibitory subunits. Despite their prominent function in regulating cGMP levels and therefore rod and cone light response properties, it is not known how each subunit contributes to the functional differences between rods and cones. In this study, we generated an rd10/cpfl1 mouse model lacking rod PDE6β and cone PDE6α’ subunits. Both rod and cone photoreceptor cells are degenerated with age and all PDE6 subunits degrade in rd10/cpfl1 mice. We expressed cone PDE6α’ in both rods and cones of rd10/cpfl1 mice by adeno-associated virus (AAV)-mediated delivery driven by the ubiquitous, constitutive small chicken β-actin promoter. We show that expression of PDE6α’ rescues rod function in rd10/cpfl1 mice, and the restoration of rod light sensitivity is attained through restoration of endogenous rod PDE6γ and formation of a functional PDE6α’γ complex. However, improved photopic cone responses were achieved only after supplementation of both cone PDE6α’ and PDE6γ’ subunits but not by PDE6α’ treatment alone. We observed a two fold increase of PDE6α’ levels in the eyes injected with both PDE6α’ plus PDE6γ’ relative to eyes receiving PDE6α’ alone. Despite the presence of both PDE6γ’ and PDE6γ, the majority of PDE6α’ formed functional complexes with PDE6γ’, suggesting that PDE6α’ has a higher association affinity for PDE6γ’ than for PDE6γ. These results suggest that the presence of PDE6γ’ augments cone PDE6 assembly and enhances its stability. Our finding has important implication for gene therapy of PDE6α’-associated achromatopsia.
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Affiliation(s)
- Wen-Tao Deng
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
| | - Saravanan Kolandaivelu
- Departments of Ophthalmology and Biochemistry, Center for Neuroscience, West Virginia University, Morgantown, WV, United States
| | - Astra Dinculescu
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
| | - Jie Li
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
| | - Ping Zhu
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
| | - Vince A Chiodo
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
| | - Visvanathan Ramamurthy
- Departments of Ophthalmology and Biochemistry, Center for Neuroscience, West Virginia University, Morgantown, WV, United States
| | - William W Hauswirth
- Department of Ophthalmology, University of Florida, Gainesville, FL, United States
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Sharon D, Wimberg H, Kinarty Y, Koch KW. Genotype-functional-phenotype correlations in photoreceptor guanylate cyclase (GC-E) encoded by GUCY2D. Prog Retin Eye Res 2018; 63:69-91. [DOI: 10.1016/j.preteyeres.2017.10.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 10/16/2017] [Accepted: 10/16/2017] [Indexed: 01/09/2023]
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15
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Kumaran N, Smith AJ, Michaelides M, Ali R, Bainbridge J. Gene therapy for Leber congenital amaurosis. EXPERT REVIEW OF OPHTHALMOLOGY 2018. [DOI: 10.1080/17469899.2018.1429916] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Neruban Kumaran
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
| | - Alexander J. Smith
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
| | - Michel Michaelides
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
| | - Robin Ali
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
| | - James Bainbridge
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
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16
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Kumaran N, Moore AT, Weleber RG, Michaelides M. Leber congenital amaurosis/early-onset severe retinal dystrophy: clinical features, molecular genetics and therapeutic interventions. Br J Ophthalmol 2017; 101:1147-1154. [PMID: 28689169 PMCID: PMC5574398 DOI: 10.1136/bjophthalmol-2016-309975] [Citation(s) in RCA: 195] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 04/26/2017] [Accepted: 04/30/2017] [Indexed: 12/29/2022]
Abstract
Leber congenital amaurosis (LCA) and early-onset severe retinal dystrophy (EOSRD) are both genetically and phenotypically heterogeneous, and characterised clinically by severe congenital/early infancy visual loss, nystagmus, amaurotic pupils and markedly reduced/absent full-field electroretinograms. The vast genetic heterogeneity of inherited retinal disease has been established over the last 10 - 20 years, with disease-causing variants identified in 25 genes to date associated with LCA/EOSRD, accounting for 70–80% of cases, with thereby more genes yet to be identified. There is now far greater understanding of the structural and functional associations seen in the various LCA/EOSRD genotypes. Subsequent development/characterisation of LCA/EOSRD animal models has shed light on the underlying pathogenesis and allowed the demonstration of successful rescue with gene replacement therapy and pharmacological intervention in multiple models. These advancements have culminated in more than 12 completed, ongoing and anticipated phase I/II and phase III gene therapy and pharmacological human clinical trials. This review describes the clinical and genetic characteristics of LCA/EOSRD and the differential diagnoses to be considered. We discuss in further detail the diagnostic clinical features, pathophysiology, animal models and human treatment studies and trials, in the more common genetic subtypes and/or those closest to intervention.
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Affiliation(s)
- Neruban Kumaran
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK.,University of California San Francisco, San Francisco CA, California, USA
| | - Richard G Weleber
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, USA
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
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17
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Biswal MR, Han P, Zhu P, Wang Z, Li H, Ildefonso CJ, Lewin AS. Timing of Antioxidant Gene Therapy: Implications for Treating Dry AMD. Invest Ophthalmol Vis Sci 2017; 58:1237-1245. [PMID: 28241311 PMCID: PMC5338629 DOI: 10.1167/iovs.16-21272] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Purpose To investigate whether antioxidant gene therapy protects the structure and function of retina in a murine model of RPE atrophy, and to determine whether antioxidant gene therapy can prevent degeneration once it has begun. Methods We induced mitochondrial oxidative stress in RPE by conditional deletion of Sod2, the gene for manganese superoxide dismutase (MnSOD). These mice exhibited localized atrophy of the RPE and overlying photoreceptors. We restored Sod2 to the RPE of one eye using adeno-associated virus (AAV) by subretinal injection at an early (6 weeks) and a late stage (6 months), injecting the other eye with an AAV vector expressing green fluorescent protein (GFP). Retinal degeneration was monitored over a period of 9 months by electroretinography (ERG) and spectral-domain optical coherence tomography (SD-OCT). Immunohistochemical and histologic analyses were conducted to measure oxidative stress markers and to visualize retinal structure. Results One month after delivery, the AAV-Sod2 injection resulted in production of MnSod in the RPE and negligible expression in the neural retina. Electroretinography and OCT suggested no adverse effects due to increased expression of MnSOD or subretinal injection. Decrease in the ERG response and thinning retinal thickness was significantly delayed in eyes with early treatment with the Sod2 vector, but treatment at 6 months of age did not affect the ERG decline seen in these mice. Conclusions We conclude that antioxidant gene therapy may be effective in preventing the detrimental effects of oxidative stress, but may not be beneficial once substantial tissue damage has occurred.
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Affiliation(s)
- Manas R Biswal
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, Florida, United States
| | - Pingyang Han
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, Florida, United States
| | - Ping Zhu
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, Florida, United States
| | - Zhaoyang Wang
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Huangpu District, Shanghai, China
| | - Hong Li
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, Florida, United States
| | - Cristhian J Ildefonso
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, Florida, United States
| | - Alfred S Lewin
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, Florida, United States
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18
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In vivo dynamics of AAV-mediated gene delivery to sensory neurons of the trigeminal ganglia. Sci Rep 2017; 7:927. [PMID: 28424485 PMCID: PMC5430444 DOI: 10.1038/s41598-017-01004-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 03/24/2017] [Indexed: 01/22/2023] Open
Abstract
The ability to genetically manipulate trigeminal ganglion (TG) neurons would be useful in the study of the craniofacial nervous system and latent alphaherpesvirus infections. We investigated adeno-associated virus (AAV) vectors for gene delivery to the TG after intradermal whiskerpad delivery in mice. We demonstrated that AAV vectors of serotypes 1, 7, 8, and 9 trafficked from the whiskerpad into TG neurons and expressed transgenes within cell bodies and axons of sensory neurons in all three branches of the TG. Gene expression was highest with AAV1, and steadily increased over time up to day 28. Both constitutive and neuronal-specific promoters were able to drive transgene expression in TG neurons. Levels of vector genomes in the TG increased with input dose, and multiple transgenes could be co-delivered to TG neurons by separate AAV vectors. In conclusion, AAV1 vectors are suitable for gene delivery to TG sensory neurons following intradermal whiskerpad injection.
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Abstract
Over the last few years, huge progress has been made with regard to the understanding of molecular mechanisms underlying the pathogenesis of neurodegenerative diseases of the eye. Such knowledge has led to the development of gene therapy approaches to treat these devastating disorders. Challenges regarding the efficacy and efficiency of therapeutic gene delivery have driven the development of novel therapeutic approaches, which continue to evolve the field of ocular gene therapy. In this review article, we will discuss the evolution of preclinical and clinical strategies that have improved gene therapy in the eye, showing that treatment of vision loss has a bright future.
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Affiliation(s)
- Lolita Petit
- 1 Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School , Worcester, Massachusetts
| | - Hemant Khanna
- 1 Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School , Worcester, Massachusetts.,2 Department of Neurobiology, University of Massachusetts Medical School , Worcester, Massachusetts
| | - Claudio Punzo
- 1 Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School , Worcester, Massachusetts.,2 Department of Neurobiology, University of Massachusetts Medical School , Worcester, Massachusetts
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20
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Dai X, Zhang H, Han J, He Y, Zhang Y, Qi Y, Pang JJ. Effects of Subretinal Gene Transfer at Different Time Points in a Mouse Model of Retinal Degeneration. PLoS One 2016; 11:e0156542. [PMID: 27228218 PMCID: PMC4882044 DOI: 10.1371/journal.pone.0156542] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 05/16/2016] [Indexed: 12/11/2022] Open
Abstract
Lysophosphatidylcholine acyltransferase 1 (LPCAT1) is necessary for photoreceptors to generate an important lipid component of their membranes. The absence of LPCAT1 results in early and rapid rod and cone degeneration. Retinal degeneration 11 (rd11) mice carry a mutation in the Lpcat1 gene, and are an excellent model of early-onset rapid retinal degeneration (RD). To date, no reports have documented gene therapy administration in the rd11 mouse model at different ages. In this study, the AAV8 (Y733F)-smCBA-Lpcat1 vector was subretinally injected at postnatal day (P) 10, 14, 18, or 22. Four months after injection, immunohistochemistry and analysis of retinal morphology showed that treatment at P10 rescued about 82% of the wild-type retinal thickness. However, the diffusion of the vector and the resulting rescue were limited to an area around the injection site that was only 31% of the total retinal area. Injection at P14 resulted in vector diffusion that covered approximately 84% of the retina, and we found that gene therapy was more effective against RD when exposure to light was limited before and after treatment. We observed long-term preservation of electroretinogram (ERG) responses, and preservation of retinal structure, indicating that early treatment followed by limited light exposure can improve gene therapy effectiveness for the eyes of rd11 mice. Importantly, delayed treatment still partially preserved M-cones, but not S-cones, and M-cones in the rd11 retina appeared to have a longer window of opportunity for effective preservation with gene therapy. These results provide important information regarding the effects of subretinal gene therapy in the mouse model of LPCAT1-deficiency.
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Affiliation(s)
- Xufeng Dai
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
- * E-mail: (XD); (JP)
| | - Hua Zhang
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
| | - Juanjuan Han
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
| | - Ying He
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
| | - Yangyang Zhang
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
| | - Yan Qi
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
| | - Ji-jing Pang
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
- * E-mail: (XD); (JP)
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21
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A Mini-review: Animal Models of GUCY2D Leber Congenital Amaurosis (LCA1). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 854:253-8. [PMID: 26427419 DOI: 10.1007/978-3-319-17121-0_34] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
GUCY2D encodes retinal guanylate cylase-1 (retGC1), a protein that plays a pivotal role in the recovery phase of phototransduction. Mutations in GUCY2D are associated with a leading cause of recessive Leber congenital amaurosis (LCA1). Patients present within the first year of life with aberrant or unrecordable electroretinogram (ERG), nystagmus and a relatively normal fundus. Aside from abnormalities in the outer segments of foveal cones and, in some patients, foveal cone loss, LCA1 patients retain normal retinal laminar architecture suggesting they may be good candidates for gene replacement therapy. Several animal models of LCA1, both naturally occurring and engineered, have been characterized and provide valuable tools for translational studies. This mini-review will summarize the phenotypes of these models and describe how each has been instrumental in proof of concept studies to develop a gene replacement therapy for GUCY2D-LCA1.
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22
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Boye SL, Peterson JJ, Choudhury S, Min SH, Ruan Q, McCullough KT, Zhang Z, Olshevskaya EV, Peshenko IV, Hauswirth WW, Ding XQ, Dizhoor AM, Boye SE. Gene Therapy Fully Restores Vision to the All-Cone Nrl(-/-) Gucy2e(-/-) Mouse Model of Leber Congenital Amaurosis-1. Hum Gene Ther 2015; 26:575-92. [PMID: 26247368 DOI: 10.1089/hum.2015.053] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mutations in GUCY2D are the cause of Leber congenital amaurosis type 1 (LCA1). GUCY2D encodes retinal guanylate cyclase-1 (retGC1), a protein expressed exclusively in outer segments of photoreceptors and essential for timely recovery from photoexcitation. Recent clinical data show that, despite a high degree of visual disturbance stemming from a loss of cone function, LCA1 patients retain normal photoreceptor architecture, except for foveal cone outer segment abnormalities and, in some patients, foveal cone loss. These results point to the cone-rich central retina as a target for GUCY2D replacement. LCA1 gene replacement studies thus far have been conducted in rod-dominant models (mouse) or with vectors and organisms lacking clinical translatability. Here we investigate gene replacement in the Nrl(-/-) Gucy2e(-/-) mouse, an all-cone model deficient in retGC1. We show that AAV-retGC1 treatment fully restores cone function, cone-mediated visual behavior, and guanylate cyclase activity, and preserves cones in treated Nrl(-/-) Gucy2e(-/-) mice over the long-term. A novel finding was that retinal function could be restored to levels above that in Nrl(-/-) controls, contrasting results in other models of retGC1 deficiency. We attribute this to increased cyclase activity in treated Nrl(-/-) Gucy2e(-/-) mice relative to Nrl(-/-) controls. Thus, Nrl(-/-) Gucy2e(-/-) mice possess an expanded dynamic range in ERG response to gene replacement relative to other models. Lastly, we show that a candidate clinical vector, AAV5-GRK1-GUCY2D, when delivered to adult Nrl(-/-) Gucy2e(-/-) mice, restores retinal function that persists for at least 6 months. Our results provide strong support for clinical application of a gene therapy targeted to the cone-rich, central retina of LCA1 patients.
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Affiliation(s)
- Sanford L Boye
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - James J Peterson
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Shreyasi Choudhury
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Seok Hong Min
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Qing Ruan
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - K Tyler McCullough
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Zhonghong Zhang
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Elena V Olshevskaya
- 2 Department of Basic Sciences Research, Salus University , Elkins Park, Pennsylvania
| | - Igor V Peshenko
- 2 Department of Basic Sciences Research, Salus University , Elkins Park, Pennsylvania
| | - William W Hauswirth
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Xi-Qin Ding
- 3 Department of Cell Biology, College of Medicine, University of Oklahoma , Oklahoma City, Oklahoma
| | - Alexander M Dizhoor
- 2 Department of Basic Sciences Research, Salus University , Elkins Park, Pennsylvania
| | - Shannon E Boye
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
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23
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Bogner B, Boye SL, Min SH, Peterson JJ, Ruan Q, Zhang Z, Reitsamer HA, Hauswirth WW, Boye SE. Capsid Mutated Adeno-Associated Virus Delivered to the Anterior Chamber Results in Efficient Transduction of Trabecular Meshwork in Mouse and Rat. PLoS One 2015; 10:e0128759. [PMID: 26052939 PMCID: PMC4460001 DOI: 10.1371/journal.pone.0128759] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 04/30/2015] [Indexed: 12/19/2022] Open
Abstract
Background Adeno associated virus (AAV) is well known for its ability to deliver transgenes to retina and to mediate improvements in animal models and patients with inherited retinal disease. Although the field is less advanced, there is growing interest in AAV’s ability to target cells of the anterior segment. The purpose of our study was to fully articulate a reliable and reproducible method for injecting the anterior chamber (AC) of mice and rats and to investigate the transduction profiles of AAV2- and AAV8-based capsid mutants containing self-complementary (sc) genomes in the anterior segment of the eye. Methodology/Principle Findings AC injections were performed in C57BL/6 mice and Sprague Dawley rats. The cornea was punctured anterior of the iridocorneal angle. To seal the puncture site and to prevent reflux an air bubble was created in the AC. scAAVs expressing GFP were injected and transduction was evaluated by immunohistochemistry. Both parent serotype and capsid modifications affected expression. scAAV2- based vectors mediated efficient GFP-signal in the corneal endothelium, ciliary non-pigmented epithelium (NPE), iris and chamber angle including trabecular meshwork, with scAAV2(Y444F) and scAAV2(triple) being the most efficient. Conclusions/Significance This is the first study to semi quantitatively evaluate transduction of anterior segment tissues following injection of capsid-mutated AAV vectors. scAAV2- based vectors transduced corneal endothelium, ciliary NPE, iris and trabecular meshwork more effectively than scAAV8-based vectors. Mutagenesis of surface-exposed tyrosine residues greatly enhanced transduction efficiency of scAAV2 in these tissues. The number of Y-F mutations was not directly proportional to transduction efficiency, however, suggesting that proteosomal avoidance alone may not be sufficient. These results are applicable to the development of targeted, gene-based strategies to investigate pathological processes of the anterior segment and may be applied toward the development of gene-based therapies for glaucoma and acquired or inherited corneal anomalies.
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Affiliation(s)
- Barbara Bogner
- Department of Ophthalmology and Optometry, SALK/Paracelsus Medical University, Salzburg, Austria
| | - Sanford L. Boye
- Department of Ophthalmology, University of Florida, Gainesville, United States of America
| | - Seok Hong Min
- Department of Ophthalmology, University of Florida, Gainesville, United States of America
| | - James J. Peterson
- Department of Ophthalmology, University of Florida, Gainesville, United States of America
| | - Qing Ruan
- Department of Ophthalmology, University of Florida, Gainesville, United States of America
| | - Zhonghong Zhang
- Department of Ophthalmology and Optometry, SALK/Paracelsus Medical University, Salzburg, Austria
| | - Herbert A. Reitsamer
- Department of Ophthalmology and Optometry, SALK/Paracelsus Medical University, Salzburg, Austria
| | - William W. Hauswirth
- Department of Ophthalmology, University of Florida, Gainesville, United States of America
| | - Shannon E. Boye
- Department of Ophthalmology, University of Florida, Gainesville, United States of America
- * E-mail:
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Induction of autophagy in rats upon overexpression of wild-type and mutant optineurin gene. BMC Cell Biol 2015; 16:14. [PMID: 25943884 PMCID: PMC4429416 DOI: 10.1186/s12860-015-0060-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 04/22/2015] [Indexed: 12/31/2022] Open
Abstract
Background Optineurin is a gene associated with normal tension glaucoma and amyotrophic lateral sclerosis. It has been reported previously that in cultured RGC5 cells, the turnover of endogenous optineurin involves mainly the ubiquitin-proteasome pathway (UPP). When optineurin is upregulated or mutated, the UPP function is compromised as evidenced by a decreased proteasome β5 subunit (PSMB5) level and autophagy is induced for clearance of the optineurin protein. Results Adeno-associated type 2 viral (AAV2) vectors for green fluorescence protein (GFP) only, GFP-tagged wild-type and Glu50Lys (E50K) mutated optineurin were intravitreally injected into rats for expression in retinal ganglion cells (RGCs). Following intravitreal injections, eyes that received optineurin vectors exhibited retinal thinning, as well as RGC and axonal loss compared to GFP controls. By immunostaining and Western blotting, the level of PSMB5 and autophagic substrate degradation marker p62 was reduced, and the level of autophagic marker microtubule associated protein 1 light chain 3 (LC3) was enhanced. The UPP impairment and autophagy induction evidently occurred in vivo as in vitro. The optineurin level, RGC and axonal counts, and apoptosis in AAV2-E50K-GFP-injected rat eyes were averted to closer to normal limits after treatment with rapamycin, an autophagic enhancer. Conclusions The UPP function was reduced and autophagy was induced when wild-type and E50K optineurin was overexpressed in rat eyes. This study validates the in vitro findings, confirming that UPP impairment and autophagy induction also occur in vivo. In addition, rapamycin is demonstrated to clear the accumulated mutant optineurin. This agent may potentially be useful for rescuing of the adverse optineurin phenotypes in vivo.
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Brennenstuhl C, Tanimoto N, Burkard M, Wagner R, Bolz S, Trifunovic D, Kabagema-Bilan C, Paquet-Durand F, Beck SC, Huber G, Seeliger MW, Ruth P, Wissinger B, Lukowski R. Targeted ablation of the Pde6h gene in mice reveals cross-species differences in cone and rod phototransduction protein isoform inventory. J Biol Chem 2015; 290:10242-55. [PMID: 25739440 DOI: 10.1074/jbc.m114.611921] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Indexed: 11/06/2022] Open
Abstract
Phosphodiesterase-6 (PDE6) is a multisubunit enzyme that plays a key role in the visual transduction cascade in rod and cone photoreceptors. Each type of photoreceptor utilizes discrete catalytic and inhibitory PDE6 subunits to fulfill its physiological tasks, i.e. the degradation of cyclic guanosine-3',5'-monophosphate at specifically tuned rates and kinetics. Recently, the human PDE6H gene was identified as a novel locus for autosomal recessive (incomplete) color blindness. However, the three different classes of cones were not affected to the same extent. Short wave cone function was more preserved than middle and long wave cone function indicating that some basic regulation of the PDE6 multisubunit enzyme was maintained albeit by a unknown mechanism. To study normal and disease-related functions of cone Pde6h in vivo, we generated Pde6h knock-out (Pde6h(-/-)) mice. Expression of PDE6H in murine eyes was restricted to both outer segments and synaptic terminals of short and long/middle cone photoreceptors, whereas Pde6h(-/-) retinae remained PDE6H-negative. Combined in vivo assessment of retinal morphology with histomorphological analyses revealed a normal overall integrity of the retinal organization and an unaltered distribution of the different cone photoreceptor subtypes upon Pde6h ablation. In contrast to human patients, our electroretinographic examinations of Pde6h(-/-) mice suggest no defects in cone/rod-driven retinal signaling and therefore preserved visual functions. To this end, we were able to demonstrate the presence of rod PDE6G in cones indicating functional substitution of PDE6. The disparities between human and murine phenotypes caused by mutant Pde6h/PDE6H suggest species-to-species differences in the vulnerability of biochemical and neurosensory pathways of the visual signal transduction system.
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Affiliation(s)
- Christina Brennenstuhl
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | | | - Markus Burkard
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | - Rebecca Wagner
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | | | | | - Clement Kabagema-Bilan
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | | | | | | | | | - Peter Ruth
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy
| | - Bernd Wissinger
- the Molecular Genetics Laboratory, Centre for Ophthalmology, University of Tuebingen, 72076 Tuebingen, Germany
| | - Robert Lukowski
- From the Institute of Pharmacy, Department of Pharmacology, Toxicology and Clinical Pharmacy,
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26
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Dyka FM, Boye SL, Chiodo VA, Hauswirth WW, Boye SE. Dual adeno-associated virus vectors result in efficient in vitro and in vivo expression of an oversized gene, MYO7A. Hum Gene Ther Methods 2014; 25:166-77. [PMID: 24568220 DOI: 10.1089/hgtb.2013.212] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Usher syndrome 1B (USH1B) is a severe, autosomal recessive, deaf-blind disorder caused by mutations in myosin 7A (MYO7A). Patients are born profoundly deaf and exhibit progressive loss of vision starting in their first decade. MYO7A is expressed in human photoreceptors and retinal pigment epithelium, but disease pathology begins in photoreceptors, highlighting the need to develop a gene replacement strategy that effectively targets this cell type. For its safety and efficacy in clinical trials and ability to transduce postmitotic photoreceptors, we have focused on developing a clinically applicable adeno-associated virus (AAV) platform for delivering full-length MYO7A cDNA (∼6.7 kb). Packaging of full-length MYO7A cDNA in AAV produces vectors with heterogeneous, fragmented genomes ("fAAV") capable of reconstituting full-length cDNA postinfection. We previously showed that fAAV vectors effectively delivered full-length MYO7A in vitro and in vivo. However, fAAV vectors are relatively inefficient and their heterogeneous genomes preclude definitive characterization, a drawback for clinical translatability. The aim of this study was to overcome these limitations by creating dual-AAV-vector platforms for USH1B with defined genomes. Human MYO7A was cloned in AAV vector pairs, each containing genomes <5 kb and intact inverted terminal repeats. One vector contained a promoter and 5' portion of the cDNA and the partner vector contained a 3' portion and polyadenylation signal. "Simple overlap" vectors share a central part of the MYO7A cDNA sequence. "Trans-splicing" and "hybrid" vectors utilize splice donor and acceptor sites with and without an additional central recombinogenic sequence, respectively. Vector pairs expressed full-length MYO7A in vitro and in vivo with equal or higher efficiency than fAAV, with a hybrid platform being most efficient. Importantly, analysis of MYO7A mRNA derived from each dual-vector platform revealed 100% fidelity to the predicted sequence. Our results suggest that dual AAV vectors with defined genetic payloads are a potential treatment option for USH1B.
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Affiliation(s)
- Frank M Dyka
- Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, FL 32610
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Abstract
Leber congenital amaurosis (LCA) is a clinically and genetically heterogeneous group of diseases that account for the most severe form of early-onset retinal dystrophy. Mutations in retinal guanylate cyclase-1 (GUCY2D) are associated with LCA1, a prevalent form. GUCY2D encodes guanylate cyclase-1 (GC1), a protein expressed in rod and cone photoreceptors that regulates cGMP and Ca(2+) levels within these cells. LCA1 patients present with severely impaired vision, reduced, or ablated electroretinogram and nystagmus. Despite a high degree of visual disturbance, LCA1 patients retain normal photoreceptor laminar architecture, except for foveal cone outer segment abnormalities and, in some patients, foveal cone loss. This article will summarize clinical characterization of patients and proof of concept gene replacement studies in several animal models of GC1 deficiency, both of which have laid the groundwork for clinical application of a gene therapy for treatment of LCA1.
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Boye SE. Insights gained from gene therapy in animal models of retGC1 deficiency. Front Mol Neurosci 2014; 7:43. [PMID: 24860425 PMCID: PMC4030156 DOI: 10.3389/fnmol.2014.00043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 04/26/2014] [Indexed: 12/29/2022] Open
Abstract
Vertebrate species possess two retinal guanylate cyclases (retGC1 and retGC2) and at least two guanylate cyclase activating proteins (GCAPs), GCAP1 and GCAP2. GCAPs function as Ca2+ sensors that regulate the activity of guanylate cyclases. Together, these proteins regulate cGMP and Ca2+ levels within the outer segments of rod and cone photoreceptors. Mutations in GUCY2D, the gene that encodes retGC1, are a leading cause of the most severe form of early onset retinal dystrophy, Leber congenital amaurosis (LCA1). These mutations, which reduce or abolish the ability of retGC1 to replenish cGMP in photoreceptors, are thought to lead to the biochemical equivalent of chronic light exposure in these cells. In spite of this, the majority of LCA1 patients retain normal photoreceptor laminar architecture aside from foveal cone outer segment abnormalities, suggesting they may be good candidates for gene replacement therapy. Work began in the 1980s to characterize multiple animal models of retGC1 deficiency. 34 years later, all models have been used in proof of concept gene replacement studies toward the goal of developing a therapy to treat GUCY2D-LCA1. Here we use the results of these studies as well as those of recent clinical studies to address specific questions relating to clinical application of a gene therapy for treatment of LCA1.
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Affiliation(s)
- Shannon E Boye
- Department of Ophthalmology, University of Florida Gainesville, FL, USA
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29
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Dai X, Han J, Qi Y, Zhang H, Xiang L, Lv J, Li J, Deng WT, Chang B, Hauswirth WW, Pang JJ. AAV-mediated lysophosphatidylcholine acyltransferase 1 (Lpcat1) gene replacement therapy rescues retinal degeneration in rd11 mice. Invest Ophthalmol Vis Sci 2014; 55:1724-34. [PMID: 24557352 DOI: 10.1167/iovs.13-13654] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The retinal degeneration 11 (rd11) mouse is a newly discovered, naturally occurring animal model with early photoreceptor dysfunction and rapid rod photoreceptor degeneration followed by cone degeneration. The rd11 mice carry a spontaneous mutation in the lysophosphatidylcholine acyltransferase 1 (Lpcat1) gene. Here, we evaluate whether gene replacement therapy using the fast-acting tyrosine-capsid mutant AAV8 (Y733F) can arrest retinal degeneration and restore retinal function in this model. METHODS The AAV8 (Y733F)-smCBA-Lpcat1 was delivered subretinally to postnatal day 14 (P14) rd11 mice in one eye only. At 10 weeks after injection, treated rd11 mice were examined by visually-guided behavior, electroretinography (ERG) and spectral domain optical coherence tomography (SD-OCT), and then killed for morphologic and biochemical examination. RESULTS Substantial scotopic and photopic ERG signals were maintained in treated rd11 eyes, whereas untreated eyes in the same animals showed extinguished signals. The SD-OCT (in vivo) and light microscopy (in vitro) showed a substantial preservation of the outer nuclear layer in most parts of the treated retina only. Almost wild-type LPCAT1 expression in photoreceptors with strong rod rhodopsin and M/S cone opsin staining, and normal visually-guided water maze behavioral performances were observed in treated rd11 mice. CONCLUSIONS The results demonstrate that the tyrosine-capsid mutant AAV8 (Y733F) vector is effective for treating rapidly degenerating models of retinal degeneration and, moreover, is more therapeutically effective than AAV2 (Y444, 500, 730F) vector with the same promoter-cDNA payload. To our knowledge, this is the first demonstration of phenotypic rescue by gene therapy in an animal model of retinal degeneration caused by Lpcat1 mutation.
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Affiliation(s)
- Xufeng Dai
- Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
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Abstract
Cone arrestin (Arr4) was discovered 20 years ago as a human X-chromosomal gene that is highly expressed in pinealocytes and cone photoreceptors. Subsequently, specific antibodies were developed to identify Arr4 and to distinguish cone photoreceptor morphology in health and disease states. These reagents were used to demonstrate Arr4 translocation from cone inner segments in the dark to outer segments with light stimulation, similarly to Arrestin 1 (Arr1) translocation in rod photoreceptors. A decade later, the Arr4 crystal structure was solved, which provided more clues about Arr4's mechanisms of action. With the creation of genetically engineered visual arrestin knockout mice, one critical function of Arr4 was clarified. In single living cones, both visual arrestins bind to light-activated, G protein receptor kinase 1 (Grk1) phosphorylated cone opsins to desensitize them, and in their absence, mouse cone pigment shutoff is delayed. Still under investigation are additional functions; however, it is clear that Arr4 has non-opsin-binding partners and diverse synaptic roles, including cellular anchoring and trafficking. Recent studies reveal Arr4 is involved in high temporal resolution and contrast sensitivity, which opens up a new direction for research on this intriguing protein. Even more exciting is the potential for therapeutic use of the Arr4 promoter with an AAV-halorhodopsin that was shown to be effective in using the remaining cones in retinal degeneration mouse models to drive inner retinal circuitry for motion detection and light/dark discrimination.
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31
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Boye SL, Peshenko IV, Huang WC, Min SH, McDoom I, Kay CN, Liu X, Dyka FM, Foster TC, Umino Y, Karan S, Jacobson SG, Baehr W, Dizhoor A, Hauswirth WW, Boye SE. AAV-mediated gene therapy in the guanylate cyclase (RetGC1/RetGC2) double knockout mouse model of Leber congenital amaurosis. Hum Gene Ther 2013; 24:189-202. [PMID: 23210611 DOI: 10.1089/hum.2012.193] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mutations in GUCY2D are associated with recessive Leber congenital amaurosis-1 (LCA1). GUCY2D encodes photoreceptor-specific, retinal guanylate cyclase-1 (RetGC1). Reports of retinal degeneration in LCA1 are conflicting; some describe no obvious degeneration and others report loss of both rods and cones. Proof of concept studies in models representing the spectrum of phenotypes is warranted. We have previously demonstrated adeno-associated virus (AAV)-mediated RetGC1 is therapeutic in GC1ko mice, a model exhibiting loss of cones only. The purpose of this study was to characterize AAV-mediated gene therapy in the RetGC1/RetGC2 double knockout (GCdko) mouse, a model lacking rod and cone function and exhibiting progressive loss of both photoreceptor subclasses. Use of this model also allowed for the evaluation of the functional efficiency of transgenic RetGC1 isozyme. Subretinal delivery of AAV8(Y733F) vector containing the human rhodopsin kinase (hGRK1) promoter driving murine Gucy2e was performed in GCdko mice at various postnatal time points. Treatment resulted in restoration of rod and cone function at all treatment ages and preservation of retinal structure in GCdko mice treated as late as 7 weeks of age. Functional gains and structural preservation were stable for at least 1 year. Treatment also conferred cortical- and subcortical-based visually-guided behavior. Functional efficiency of transgenic RetGC1 was indistinguishable from that of endogenous isozyme in congenic wild-type (WT) mice. This study clearly demonstrates AAV-mediated RetGC1 expression restores function to and preserves structure of rod and cone photoreceptors in a degenerative model of retinal guanylate cyclase deficiency, further supporting development of an AAV-based vector for treatment of LCA1.
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Affiliation(s)
- Sanford L Boye
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
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Retinal gene therapy with a large MYO7A cDNA using adeno-associated virus. Gene Ther 2013; 20:824-33. [PMID: 23344065 PMCID: PMC3640772 DOI: 10.1038/gt.2013.3] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 11/12/2012] [Accepted: 12/27/2012] [Indexed: 11/11/2022]
Abstract
Usher 1 patients are born profoundly deaf and then develop retinal degeneration. Thus they are readily identified prior to the onset of retinal degeneration, making gene therapy a viable strategy to prevent their blindness. Here, we have investigated the use of adeno-associated viruses (AAV) for the delivery of the Usher 1B gene, MYO7A, to retinal cells in cell culture and in Myo7a-null mice. MYO7A cDNA, under control of a smCBA promoter, was packaged in single AAV2 and AAV5 vectors, and as two overlapping halves in dual AAV2 vectors. The 7.9-kb smCBA-MYO7A exceeds the capacity of an AAV vector; packaging of such oversized constructs into single AAV vectors may involve fragmentation of the gene. Nevertheless, the AAV2 and AAV5 single vector preparations successfully transduced photoreceptor and RPE cells, resulting in functional, full-length MYO7A protein and correction of mutant phenotypes, suggesting successful homologous recombination of gene fragments. With discrete, conventional-sized dual AAV2 vectors, full-length MYO7A was detected, but the level of protein expression was variable, and only a minority of cells showed phenotype correction. Our results show that MYO7A therapy with AAV2 or AAV5 single vectors is efficacious, however, the dual AAV2 approach proved to be less effective.
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Smith WC. The role of arrestins in visual and disease processes of the eye. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 118:243-65. [PMID: 23764057 DOI: 10.1016/b978-0-12-394440-5.00010-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Visual arrestins are well known for their function in quenching the phototransduction process in rods and cones. Perhaps not as well known is their participation in multiple other processes in the normal and disease states of the eye. This chapter covers the range of the known functions of the visual arrestins, beginning with their classical role in quenching light-activated visual pigments. The role of visual arrestins is also reviewed from the perspective of their dynamic mobility whereby they redistribute significantly between the compartments of highly polarized photoreceptor cells. Additional roles of the visual arrestins are also reviewed based on new interacting partners that have been discovered over the past decade. Finally, the contribution of the visual arrestins to diseases of the visual system is explored.
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Affiliation(s)
- W Clay Smith
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
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Kay CN, Ryals RC, Aslanidi GV, Min SH, Ruan Q, Sun J, Dyka FM, Kasuga D, Ayala AE, Van Vliet K, Agbandje-McKenna M, Hauswirth WW, Boye SL, Boye SE. Targeting photoreceptors via intravitreal delivery using novel, capsid-mutated AAV vectors. PLoS One 2013; 8:e62097. [PMID: 23637972 PMCID: PMC3637363 DOI: 10.1371/journal.pone.0062097] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 03/16/2013] [Indexed: 12/23/2022] Open
Abstract
Development of viral vectors capable of transducing photoreceptors by less invasive methods than subretinal injection would provide a major advancement in retinal gene therapy. We sought to develop novel AAV vectors optimized for photoreceptor transduction following intravitreal delivery and to develop methodology for quantifying this transduction in vivo. Surface exposed tyrosine (Y) and threonine (T) residues on the capsids of AAV2, AAV5 and AAV8 were changed to phenylalanine (F) and valine (V), respectively. Transduction efficiencies of self-complimentary, capsid-mutant and unmodified AAV vectors containing the smCBA promoter and mCherry cDNA were initially scored in vitro using a cone photoreceptor cell line. Capsid mutants exhibiting the highest transduction efficiencies relative to unmodified vectors were then injected intravitreally into transgenic mice constitutively expressing a Rhodopsin-GFP fusion protein in rod photoreceptors (Rho-GFP mice). Photoreceptor transduction was quantified by fluorescent activated cell sorting (FACS) by counting cells positive for both GFP and mCherry. To explore the utility of the capsid mutants, standard, (non-self-complementary) AAV vectors containing the human rhodopsin kinase promoter (hGRK1) were made. Vectors were intravitreally injected in wildtype mice to assess whether efficient expression exclusive to photoreceptors was achievable. To restrict off-target expression in cells of the inner and middle retina, subsequent vectors incorporated multiple target sequences for miR181, an miRNA endogenously expressed in the inner and middle retina. Results showed that AAV2 containing four Y to F mutations combined with a single T to V mutation (quadY-F+T-V) transduced photoreceptors most efficiently. Robust photoreceptor expression was mediated by AAV2(quadY-F+T-V) -hGRK1-GFP. Observed off-target expression was reduced by incorporating target sequence for a miRNA highly expressed in inner/middle retina, miR181c. Thus we have identified a novel AAV vector capable of transducing photoreceptors following intravitreal delivery to mouse. Furthermore, we describe a robust methodology for quantifying photoreceptor transduction from intravitreally delivered AAV vectors.
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Affiliation(s)
- Christine N. Kay
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Renee C. Ryals
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - George V. Aslanidi
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Seok Hong Min
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Qing Ruan
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Jingfen Sun
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Frank M. Dyka
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Daniel Kasuga
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Andrea E. Ayala
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Kim Van Vliet
- Department of Biochemistry and Molecular Biology, University of Florida, College of Medicine, Gainesville, Florida, United States of America
| | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology, University of Florida, College of Medicine, Gainesville, Florida, United States of America
| | - William W. Hauswirth
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Sanford L. Boye
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Shannon E. Boye
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, Florida, United States of America
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, Florida, United States of America
- * E-mail:
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Development of an anti-angiogenic therapeutic model combining scAAV2-delivered siRNAs and noninvasive photoacoustic imaging of tumor vasculature development. Cancer Lett 2012. [PMID: 23196055 DOI: 10.1016/j.canlet.2012.11.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We aimed to develop an anti-angiogenic model for breast cancer by combining (1) siRNA-based therapy delivered by self-complementary adeno-associated virus serotype 2 (scAAV2) vectors to target tumor vasculature, and (2) noninvasive monitoring to tumor response to anti-angiogenesis by photoacoustic (PA) imaging. scAAV2 vector containing 7 surface exposed tyrosine to phenylanine capsid mutations was able to transduce microvascular endothelial cells with high efficiency. siRNAs against UPR (unfolded protein response)-IRE1α, XBP-1, ATF6 significantly inhibited breast cancer-induced angiogenesis in vitro by inhibiting endothelial cell survival. PA imaging showed that knockdown of UPR proteins greatly reduced tumor angiogenesis in vivo in breast cancer models.
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Jacobson SG, Cideciyan AV, Peshenko IV, Sumaroka A, Olshevskaya EV, Cao L, Schwartz SB, Roman AJ, Olivares MB, Sadigh S, Yau KW, Heon E, Stone EM, Dizhoor AM. Determining consequences of retinal membrane guanylyl cyclase (RetGC1) deficiency in human Leber congenital amaurosis en route to therapy: residual cone-photoreceptor vision correlates with biochemical properties of the mutants. Hum Mol Genet 2012; 22:168-83. [PMID: 23035049 DOI: 10.1093/hmg/dds421] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The GUCY2D gene encodes retinal membrane guanylyl cyclase (RetGC1), a key component of the phototransduction machinery in photoreceptors. Mutations in GUCY2D cause Leber congenital amaurosis type 1 (LCA1), an autosomal recessive human retinal blinding disease. The effects of RetGC1 deficiency on human rod and cone photoreceptor structure and function are currently unknown. To move LCA1 closer to clinical trials, we characterized a cohort of patients (ages 6 months-37 years) with GUCY2D mutations. In vivo analyses of retinal architecture indicated intact rod photoreceptors in all patients but abnormalities in foveal cones. By functional phenotype, there were patients with and those without detectable cone vision. Rod vision could be retained and did not correlate with the extent of cone vision or age. In patients without cone vision, rod vision functioned unsaturated under bright ambient illumination. In vitro analyses of the mutant alleles showed that in addition to the major truncation of the essential catalytic domain in RetGC1, some missense mutations in LCA1 patients result in a severe loss of function by inactivating its catalytic activity and/or ability to interact with the activator proteins, GCAPs. The differences in rod sensitivities among patients were not explained by the biochemical properties of the mutants. However, the RetGC1 mutant alleles with remaining biochemical activity in vitro were associated with retained cone vision in vivo. We postulate a relationship between the level of RetGC1 activity and the degree of cone vision abnormality, and argue for cone function being the efficacy outcome in clinical trials of gene augmentation therapy in LCA1.
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Affiliation(s)
- Samuel G Jacobson
- Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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Boye SE, Alexander JJ, Boye SL, Witherspoon CD, Sandefer KJ, Conlon TJ, Erger K, Sun J, Ryals R, Chiodo VA, Clark ME, Girkin CA, Hauswirth WW, Gamlin PD. The human rhodopsin kinase promoter in an AAV5 vector confers rod- and cone-specific expression in the primate retina. Hum Gene Ther 2012; 23:1101-15. [PMID: 22845794 DOI: 10.1089/hum.2012.125] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Adeno-associated virus (AAV) has proven an effective gene delivery vehicle for the treatment of retinal disease. Ongoing clinical trials using a serotype 2 AAV vector to express RPE65 in the retinal pigment epithelium have proven safe and effective. While many proof-of-concept studies in animal models of retinal disease have suggested that gene transfer to the neural retina will also be effective, a photoreceptor-targeting AAV vector has yet to be used in the clinic, principally because a vector that efficiently but exclusively targets all primate photoreceptors has yet to be demonstrated. Here, we evaluate a serotype 5 AAV vector containing the human rhodopsin kinase (hGRK1) promoter for its ability to target transgene expression to rod and cone photoreceptors when delivered subretinally in a nonhuman primate (NHP). In vivo fluorescent fundus imaging confirmed that AAV5-hGRK1-mediated green fluorescent protein (GFP) expression was restricted to the injection blebs of treated eyes. Optical coherence tomography (OCT) revealed a lack of gross pathology after injection. Neutralizing antibodies against AAV5 were undetectable in post-injection serum samples from subjects receiving uncomplicated subretinal injections (i.e., no hemorrhage). Immunohistochemistry of retinal sections confirmed hGRK1 was active in, and specific for, both rods and cones of NHP retina. Biodistribution studies revealed minimal spread of vector genomes to peripheral tissues. These results suggest that AAV5-hGRK1 is a safe and effective AAV serotype/promoter combination for targeting therapeutic transgene expression protein to rods and cones in a clinical setting.
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Affiliation(s)
- Shannon E Boye
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL 32610, USA.
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Pang JJ, Lei L, Dai X, Shi W, Liu X, Dinculescu A, McDowell JH. AAV-mediated gene therapy in mouse models of recessive retinal degeneration. Curr Mol Med 2012; 12:316-30. [PMID: 22300136 DOI: 10.2174/156652412799218877] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 08/23/2011] [Accepted: 10/25/2011] [Indexed: 02/01/2023]
Abstract
In recent years, more and more mutant genes that cause retinal diseases have been detected. At the same time, many naturally occurring mouse models of retinal degeneration have also been found, which show similar changes to human retinal diseases. These, together with improved viral vector quality allow more and more traditionally incurable inherited retinal disorders to become potential candidates for gene therapy. Currently, the most common vehicle to deliver the therapeutic gene into target retinal cells is the adenoassociated viral vector (AAV). Following delivery to the immuno-privileged subretinal space, AAV-vectors can efficiently target both retinal pigment epithelium and photoreceptor cells, the origin of most retinal degenerations. This review focuses on the AAV-based gene therapy in mouse models of recessive retinal degenerations, especially those in which delivery of the correct copy of the wild-type gene has led to significant beneficial effects on visual function, as determined by morphological, biochemical, electroretinographic and behavioral analysis. The past studies in animal models and ongoing successful LCA2 clinical trials, predict a bright future for AAV gene replacement treatment for inherited recessive retinal diseases.
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Affiliation(s)
- J-J Pang
- Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical College, China.
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Deng WT, Dinculescu A, Li Q, Boye SL, Li J, Gorbatyuk MS, Pang J, Chiodo VA, Matthes MT, Yasumura D, Liu L, Alkuraya FS, Zhang K, Vollrath D, LaVail MM, Hauswirth WW. Tyrosine-mutant AAV8 delivery of human MERTK provides long-term retinal preservation in RCS rats. Invest Ophthalmol Vis Sci 2012; 53:1895-904. [PMID: 22408006 DOI: 10.1167/iovs.11-8831] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The absence of Mertk in RCS rats results in defective RPE phagocytosis, accumulation of outer segment (OS) debris in the subretinal space, and subsequent death of photoreceptors. Previous research utilizing Mertk gene replacement therapy in RCS rats provided proof of concept for treatment of this form of recessive retinitis pigmentosa (RP); however, the beneficial effects on retinal function were transient. In the present study, we evaluated whether delivery of a MERTK transgene using a tyrosine-mutant AAV8 capsid could lead to more robust and longer-term therapeutic outcomes than previously reported. METHODS An AAV8 Y733F vector expressing a human MERTK cDNA driven by a RPE-selective promoter was administrated subretinally at postnatal day 2. Functional and morphological analyses were performed at 4 months and 8 months post-treatment. Retinal vasculature and Müller cell activation were analyzed by quantifying acellular capillaries and glial fibrillary acidic protein immunostaining, respectively. RESULTS Electroretinographic responses from treated eyes were more than one-third of wild-type levels and OS were well preserved in the injection area even at 8 months. Rescue of RPE phagocytosis, prevention of retinal vasculature degeneration, and inhibition of Müller cell activation were demonstrated in the treated eyes for at least 8 months. CONCLUSIONS This research describes a longer and much more robust functional and morphological rescue than previous studies. We also demonstrate for the first time that an AAV8 mutant capsid serotype vector has a substantial therapeutic potential for RPE-specific gene delivery. These results suggest that tyrosine-mutant AAV8 vectors hold promise for the treatment of individuals with MERTK-associated RP.
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Affiliation(s)
- Wen-Tao Deng
- Department of Ophthalmology, College of Medicine, University of Florida, 1600 SW Archer Road, Gainesville, FL 32610, USA.
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Schmitz F, Natarajan S, Venkatesan JK, Wahl S, Schwarz K, Grabner CP. EF hand-mediated Ca- and cGMP-signaling in photoreceptor synaptic terminals. Front Mol Neurosci 2012; 5:26. [PMID: 22393316 PMCID: PMC3289946 DOI: 10.3389/fnmol.2012.00026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 02/15/2012] [Indexed: 12/11/2022] Open
Abstract
Photoreceptors, the light-sensitive receptor neurons of the retina, receive and transmit a plethora of visual informations from the surrounding world. Photoreceptors capture light and convert this energy into electrical signals that are conveyed to the inner retina. For synaptic communication with the inner retina, photoreceptors make large active zones that are marked by synaptic ribbons. These unique synapses support continuous vesicle exocytosis that is modulated by light-induced, graded changes of membrane potential. Synaptic transmission can be adjusted in an activity-dependent manner, and at the synaptic ribbons, Ca2+- and cGMP-dependent processes appear to play a central role. EF-hand-containing proteins mediate many of these Ca2+- and cGMP-dependent functions. Since continuous signaling of photoreceptors appears to be prone to malfunction, disturbances of Ca2+- and cGMP-mediated signaling in photoreceptors can lead to visual defects, retinal degeneration (rd), and even blindness. This review summarizes aspects of signal transmission at the photoreceptor presynaptic terminals that involve EF-hand-containing Ca2+-binding proteins.
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Affiliation(s)
- Frank Schmitz
- Department of Neuroanatomy, Medical School Homburg/Saar, Institute for Anatomy and Cell Biology, Saarland University Saarland, Germany
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Gucy2f zebrafish knockdown--a model for Gucy2d-related leber congenital amaurosis. Eur J Hum Genet 2012; 20:884-9. [PMID: 22378290 DOI: 10.1038/ejhg.2012.10] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Mutations in retinal-specific guanylate cyclase (Gucy2d) are associated with Leber congenital amaurosis-1 (LCA1). Zebrafish offer unique advantages relative to rodents, including their excellent color vision, precocious retinal development, robust visual testing strategies, low cost, relatively easy transgenesis and shortened experimental times. In this study we will demonstrate the feasibility of using gene-targeting in the zebrafish as a model for the photoreceptor-specific GUCY2D-related LCA1, by reporting the visual phenotype and retinal histology resulting from Gucy2f knockdown. Gucy2f zebrafish LCA-orthologous cDNA was identified and isolated by PCR amplification. Its expression pattern was determined by whole-mount in-situ hybridization and its function was studied by gene knockdown using two different morpholino-modified oligos (MO), one that blocks translation of Gucy2f and one that blocks splicing of Gucy2f. Visual function was assessed with an optomotor assay on 6-days-post-fertilization larvae, and by analyzing changes in retinal histology. Gucy2f knockdown resulted in significantly lower vision as measured by the optomotor response compared with uninjected and control MO-injected zebrafish larvae. Histological changes in the Gucy2f-knockdown larvae included loss and shortening of cone and rod outer segments. A zebrafish model of Gucy2f-related LCA1 displays early visual dysfunction and photoreceptor layer dystrophy. This study serves as proof of concept for the use of zebrafish as a simple, inexpensive model with excellent vision on which further study of LCA-related genes is possible.
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Abstract
Retinal gene therapy holds great promise for the treatment of inherited and noninherited blinding diseases such as retinitis pigmentosa and age-related macular degeneration. The most widely used vectors for ocular gene delivery are based on adeno-associated virus (AAV) because it mediates long-term transgene expression in a variety of retinal cell types and elicits minimal immune responses. Inherited retinal diseases are nonlethal and have a wide level of genetic heterogeneity. Many of the genes have now been identified and their function elucidated, providing a major step towards the development of gene-based treatments. Extensive preclinical evaluation of gene transfer strategies in small and large animal models is key to the development of successful gene-based therapies for the retina. These preclinical studies have already allowed the field to reach the point where gene therapy to treat inherited blindness has been brought to clinical trial.In this chapter, we focus on AAV-mediated specific gene therapy for inherited retinal degenerative diseases, describing the disease targets, the preclinical studies in animal models and the recent success of the LCA-RPE65 clinical trials.
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Boye SL, Conlon T, Erger K, Ryals R, Neeley A, Cossette T, Pang J, Dyka FM, Hauswirth WW, Boye SE. Long-term preservation of cone photoreceptors and restoration of cone function by gene therapy in the guanylate cyclase-1 knockout (GC1KO) mouse. Invest Ophthalmol Vis Sci 2011; 52:7098-108. [PMID: 21778276 DOI: 10.1167/iovs.11-7867] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
PURPOSE The authors previously showed that subretinal delivery of AAV5 vectors containing murine guanylate cyclase-1 (GC1) cDNA driven by either photoreceptor-specific (hGRK1) or ubiquitous (smCBA) promoters was capable of restoring cone-mediated function and visual behavior and preserving cone photoreceptors in the GC1 knockout (GC1KO) mouse for 3 months. Here, the authors compared therapy conferred by the aforementioned vectors to that achieved with the highly efficient capsid tyrosine mutant AAV8(Y733F) and asked whether long-term therapy is achievable in this model. METHODS AAV5-hGRK1-mGC1, AAV5-smCBA-mGC1, or AAV8(Y733F)-hGRK1-mGC1 was delivered subretinally to GC1KO mice between postnatal day (P)14 and P25. Retinal function was assayed by electroretinography. Localization of AAV-mediated GC1 expression and cone survival were assayed with immunohistochemistry, and the spread of vector genomes beyond the retina was quantified by PCR of optic nerve and brain tissue. RESULTS Cone function was restored with all vectors tested, with AAV8(Y733F) being the most efficient. Electroretinographic responses were clearly measurable out to 1 year after treatment. AAV-mediated expression of GC1 was found exclusively in photoreceptors out to 15 months after injection. Cones were preserved for at least 11 months after treatment. AAV5- and AAV8(733)-delivered vector genomes were recovered primarily from optic nerve of the treated eye and, in only instance, from brain (1 of 20 samples). CONCLUSIONS The authors demonstrate for the first time that long-term therapy (∼1 year) is achievable in a mammalian model of GC1 deficiency. These data provide additional justification for the development of an AAV-based gene therapy vector for the clinical treatment of Leber congenital amaurosis-1.
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Affiliation(s)
- Sanford L Boye
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
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Mihelec M, Pearson RA, Robbie SJ, Buch PK, Azam SA, Bainbridge JWB, Smith AJ, Ali RR. Long-term preservation of cones and improvement in visual function following gene therapy in a mouse model of leber congenital amaurosis caused by guanylate cyclase-1 deficiency. Hum Gene Ther 2011; 22:1179-90. [PMID: 21671801 DOI: 10.1089/hum.2011.069] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Leber congenital amaurosis (LCA) is a severe retinal dystrophy manifesting from early infancy as poor vision or blindness. Loss-of-function mutations in GUCY2D cause LCA1 and are one of the most common causes of LCA, accounting for 20% of all cases. Human GUCY2D and mouse Gucy2e genes encode guanylate cyclase-1 (GC1), which is responsible for restoring the dark state in photoreceptors after light exposure. The Gucy2e(-/-) mouse shows partially diminished rod function, but an absence of cone function before degeneration. Although the cones appear morphologically normal, they exhibit mislocalization of proteins involved in phototransduction. In this study we tested the efficacy of an rAAV2/8 vector containing the human rhodopsin kinase promoter and the human GUCY2D gene. Following subretinal delivery of the vector in Gucy2e(-/-) mice, GC1 protein was detected in the rod and cone outer segments, and in transduced areas of retina cone transducin was appropriately localized to cone outer segments. Moreover, we observed a dose-dependent restoration of rod and cone function and an improvement in visual behavior of the treated mice. Most importantly, cone preservation was observed in transduced areas up to 6 months post injection. To date, this is the most effective rescue of the Gucy2e(-/-) mouse model of LCA and we propose that a vector, similar to the one used in this study, could be suitable for use in a clinical trial of gene therapy for LCA1.
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Affiliation(s)
- Marija Mihelec
- Department of Genetics, University College London, Institute of Ophthalmology, London, United Kingdom
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Ryals RC, Boye SL, Dinculescu A, Hauswirth WW, Boye SE. Quantifying transduction efficiencies of unmodified and tyrosine capsid mutant AAV vectors in vitro using two ocular cell lines. Mol Vis 2011; 17:1090-102. [PMID: 21552473 PMCID: PMC3087449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Accepted: 04/25/2011] [Indexed: 10/25/2022] Open
Abstract
PURPOSE With the increasing number of retinal gene-based therapies and therapeutic constructs, in vitro bioassays characterizing vector transduction efficiency and quality are becoming increasingly important. Currently, in vitro assays quantifying vector transduction efficiency are performed predominantly for non-ocular tissues. A human retinal pigment epithelial cell line (ARPE19) and a mouse cone photoreceptor cell line, 661W, have been well characterized and are used for many retinal metabolism and biologic pathway studies. The purpose of this study is to quantify transduction efficiencies of a variety of self-complementary (sc) adeno-associated virus (AAV) vectors in these biologically relevant ocular cell lines using high-throughput fluorescence-activated cell sorting (FACS) analysis. METHODS ARPE19 and 661W cells were infected with sc-smCBA-mCherry packaged in unmodified AAV capsids or capsids containing single/multiple tyrosine-phenylalanine (Y-F) mutations at multiplicity of infections (MOIs) ranging from 100 to 10,000. Three days post infection fluorescent images verified mCherry expression. Following microscopy, FACS analysis was performed to quantify the number of positive cells and the mean intensity of mCherry fluorescence, the product of which is reported as transduction efficiency for each vector. The scAAV vectors containing cone-specific (sc-mCARpro-green fluorescent protein [GFP]), rod-specific (sc-MOPS500-eGFP), retinal pigment epithelium (RPE)-specific (sc-VMD2-GFP), or ubiquitous (sc-smCBA-GFP) promoters were used to infect both cell lines at an MOI of 10,000. Three days post infection, cells were immunostained with an antibody raised against GFP and imaged. Finally, based on our in vitro results, we tested a prediction of transduction efficiency in vivo. RESULTS Expression from unmodified scAAV1, scAAV2, scAAV5, and scAAV8 vectors was detectable by FACS in both ARPE19 and 661W cells, with scAAV1 and scAAV2 being the most efficient in both cell lines. scAAV5 showed moderate efficiency in both ARPE19 and 661W cells. scAAV8 was moderately efficient in 661W cells and was by comparison less so in ARPE19 cells; however, transduction was still apparent. scAAV9 performed poorly in both cell types. With some exceptions, the Y-F capsid mutations generally increased the efficiency of scAAV vector transduction, with the increasing number of mutated residues improving efficiency. Results for single scAAV1 and scAAV8 capsid mutants were mixed. In some cases, efficiency improved; in others, it was unchanged or marginally reduced. Retinal-specific promoters were also active in both cell lines, with the 661W cells showing a pattern consistent with the in vivo activity of the respective promoters tested. The prediction based on in vitro data that AAV2 sextuple Y-F mutants would show higher transduction efficiency in RPE relative to AAV2 triple Y-F capsid mutants was validated by evaluating the transduction characteristics of the two mutant vectors in mouse retina. CONCLUSIONS Our results suggest that this rapid and quantifiable cell-based assay using two biologically relevant ocular cell lines will prove useful in screening and optimizing AAV vectors for application in retina-targeted gene therapies.
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Long-term retinal function and structure rescue using capsid mutant AAV8 vector in the rd10 mouse, a model of recessive retinitis pigmentosa. Mol Ther 2010; 19:234-42. [PMID: 21139570 DOI: 10.1038/mt.2010.273] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The retinal degeneration 10 (rd10) mouse is a well-characterized model of autosomal recessive retinitis pigmentosa (RP), which carries a spontaneous mutation in the β subunit of rod cGMP-phosphodiesterase (PDEβ). Rd10 mouse exhibits photoreceptor dysfunction and rapid rod photoreceptor degeneration followed by cone degeneration and remodeling of the inner retina. Here, we evaluate whether gene replacement using the fast-acting tyrosine-capsid mutant AAV8 (Y733F) can provide long-term therapy in this model. AAV8 (Y733F)-smCBA-PDEβ was subretinally delivered to postnatal day 14 (P14) rd10 mice in one eye only. Six months after injection, spectral domain optical coherence tomography (SD-OCT), electroretinogram (ERG), optomotor behavior tests, and immunohistochemistry showed that AAV8 (Y733F)-mediated PDEβ expression restored retinal function and visual behavior and preserved retinal structure in treated rd10 eyes for at least 6 months. This is the first demonstration of long-term phenotypic rescue by gene therapy in an animal model of PDEβ-RP. It is also the first example of tyrosine-capsid mutant AAV8 (Y733F)-mediated correction of a retinal phenotype. These results lay the groundwork for the development of PDEβ-RP gene therapy trial and suggest that tyrosine-capsid mutant AAV vectors may be effective for treating other rapidly degenerating models of retinal degeneration.
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den Hollander AI, Black A, Bennett J, Cremers FPM. Lighting a candle in the dark: advances in genetics and gene therapy of recessive retinal dystrophies. J Clin Invest 2010; 120:3042-53. [PMID: 20811160 DOI: 10.1172/jci42258] [Citation(s) in RCA: 156] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Nonsyndromic recessive retinal dystrophies cause severe visual impairment due to the death of photoreceptor and retinal pigment epithelium cells. These diseases until recently have been considered to be incurable. Molecular genetic studies in the last two decades have revealed the underlying molecular causes in approximately two-thirds of patients. The mammalian eye has been at the forefront of therapeutic trials based on gene augmentation in humans with an early-onset nonsyndromic recessive retinal dystrophy due to mutations in the retinal pigment epithelium-specific protein 65kDa (RPE65) gene. Tremendous challenges still lie ahead to extrapolate these studies to other retinal disease-causing genes, as human gene augmentation studies require testing in animal models for each individual gene and sufficiently large patient cohorts for clinical trials remain to be identified through cost-effective mutation screening protocols.
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Affiliation(s)
- Anneke I den Hollander
- Department of Ophthalmology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands
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Boye SE, Boye SL, Pang J, Ryals R, Everhart D, Umino Y, Neeley AW, Besharse J, Barlow R, Hauswirth WW. Functional and behavioral restoration of vision by gene therapy in the guanylate cyclase-1 (GC1) knockout mouse. PLoS One 2010; 5:e11306. [PMID: 20593011 PMCID: PMC2892468 DOI: 10.1371/journal.pone.0011306] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Accepted: 06/04/2010] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Recessive mutations in guanylate cyclase-1 (Gucy2d) are associated with severe, early onset Leber congenital amaurosis-1(LCA1). Gucy2d encodes guanylate cyclase (GC1) is expressed in photoreceptor outer segment membranes and produces cGMP in these cells. LCA1 patients present in infancy with severely impaired vision and extinguished electroretinogram (ERG) but retain some photoreceptors in both their macular and peripheral retina for years. Like LCA1 patients, loss of cone function in the GC1 knockout (GC1KO) mouse precedes cone degeneration. The purpose of this study was to test whether delivery of functional GC1 to cone cells of the postnatal GC1KO mouse could restore function to these cells. METHODOLOGY/PRINCIPAL FINDINGS Serotype 5 AAV vectors containing either a photoreceptor-specific, rhodopsin kinase (hGRK1) or ubiquitous (smCBA) promoter driving expression of wild type murine GC1 were subretinally delivered to one eye of P14 GC1KO mice. Visual function (ERG) was analyzed in treated and untreated eyes until 3 months post injection. AAV-treated, isogenic wild type and uninjected control mice were evaluated for restoration of visual behavior using optomotor testing. At 3 months post injection, all animals were sacrificed, and their treated and untreated retinas assayed for expression of GC1 and localization of cone arrestin. Cone-mediated function was restored to treated eyes of GC1KO mice (ERG amplitudes were approximately 45% of normal). Treatment effect was stable for at least 3 months. Robust improvements in cone-mediated visual behavior were also observed, with responses of treated mice being similar or identical to that of wild type mice. AAV-vectored GC1 expression was found in photoreceptors and cone cells were preserved in treated retinas. CONCLUSIONS/SIGNIFICANCE This is the first demonstration of gene-based restoration of both visual function/vision-elicited behavior and cone preservation in a mammalian model of GC1 deficiency. Importantly, results were obtained using a well characterized, clinically relevant AAV vector. These results lay the ground work for the development of an AAV-based gene therapy vector for the treatment of LCA1.
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Affiliation(s)
- Shannon E Boye
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, United States of America.
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Kong F, Li W, Li X, Zheng Q, Dai X, Zhou X, Boye SL, Hauswirth WW, Qu J, Pang JJ. Self-complementary AAV5 vector facilitates quicker transgene expression in photoreceptor and retinal pigment epithelial cells of normal mouse. Exp Eye Res 2010; 90:546-54. [PMID: 20138034 PMCID: PMC2854182 DOI: 10.1016/j.exer.2010.01.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 01/25/2010] [Accepted: 01/25/2010] [Indexed: 12/27/2022]
Abstract
To clarify whether transduction efficiency and cell type specificity of self-complementary (sc) AAV5 vectors are similar to those of standard, single-stranded AAV5 vectors in normal retina, one micro liter of scAAV5-smCBA-GFP vector (1 x 10(12) genome-containing particles/ml) and AAV5-smCBA-GFP vector (1 x 10(12) genome-containing particles/ml) were subretinally or intravitreally (in both cases through the cornea) injected into the right and left eyes of adult C57BL/6J mice, respectively. On post-injection day (PID) 1, 2, 5, 7, 10, 14, 21, 28 and 35, eyes were enucleated; retinal pigment epithelium (RPE) wholemounts, neuroretinal wholemounts and eyecup sections were prepared to evaluate green fluorescent protein (GFP) expression by fluorescent microscopy. GFP expression following trans-cornea subretinal injection of scAAV5-smCBA-GFP vector was first detected in RPE wholemounts around PID 1 and in neuroretinal wholemounts between PID 2 and 5; GFP expression peaked and stabilized between PID 10-14 in RPE wholemounts and between P14 and P21 in neuroretinal wholemounts with strong, homogeneous green fluorescence covering the entire wholemounts. The frozen sections supported the following findings from the wholemounts: GFP expression appeared first in RPE around PID 1-2 and soon spread to photoreceptors (PR) cells; by PID 7, moderate GFP expression was found mainly in PR and RPE layers; between PID 14 and 21, strong and homogenous GFP expression was observed in RPE and PR cells. GFP expression following subretinal injection of AAV5-smCBA-GFP was first detected in RPE wholemounts around PID 5-7 and in neuroretinal wholemounts around PID 7-10; ssAAV5-mediated GFP expression peaked at PID 21 in RPE wholemounts and around PID 28 in neuroretinal wholemounts; sections from AAV5 treated eyes also supported findings obtained from wholemounts: GFP expression was first detected in RPE and then spread to the PR cells. Peak GFP expression in RPE mediated by scAAV5 was similar to that mediated by AAV5. However, peak GFP expression mediated by scAAV5 in PR cells was stronger than that mediated by AAV5. No GFP fluorescence was detected in any retinal cells (RPE wholemounts, neuroretinal wholemounts and retinal sections) after trans-cornea intravitreal delivery of either scAAV5-GFP or AAV5-GFP. Neither scAAV5 nor AAV5 can transduce retinal cells following trans-cornea intravitreal injection. The scAAV5 vector used in this study directs an earlier onset of transgene expression than the matched AAV5 vector, and has stronger transgene expression in PR cells following subretinal injection. Our data confirm the previous reports that scAAV vectors have an earlier onset than the standard, single strand AAV vectors (Natkunarajah et al., 2008; Yokoi et al., 2007). scAAV5 vectors may be more useful than standard, single-stranded AAV vector when addressing certain RPE and/or PR cell-related models of retinal dystrophy, particularly for mouse models of human retinitis pigmentosa that require rapid and robust transgene expression to prevent early degeneration in PR cells.
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Affiliation(s)
- Fansheng Kong
- Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical College, Wenzhou, China 325027
| | - Wensheng Li
- Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical College, Wenzhou, China 325027
| | - Xia Li
- Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical College, Wenzhou, China 325027
| | - Qinxiang Zheng
- Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical College, Wenzhou, China 325027
| | - Xufeng Dai
- Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical College, Wenzhou, China 325027
| | - Xiangtian Zhou
- Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical College, Wenzhou, China 325027
| | - Sanford L. Boye
- Ophthalmology, University of Florida College of Medicine, Gainesville, FL 32610, U.S.A
| | - William W. Hauswirth
- Ophthalmology, University of Florida College of Medicine, Gainesville, FL 32610, U.S.A
| | - Jia Qu
- Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical College, Wenzhou, China 325027
| | - Ji-jing Pang
- Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical College, Wenzhou, China 325027
- Ophthalmology, University of Florida College of Medicine, Gainesville, FL 32610, U.S.A
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Pang J, Boye SE, Lei B, Boye SL, Everhart D, Ryals R, Umino Y, Rohrer B, Alexander J, Li J, Dai X, Li Q, Chang B, Barlow R, Hauswirth WW. Self-complementary AAV-mediated gene therapy restores cone function and prevents cone degeneration in two models of Rpe65 deficiency. Gene Ther 2010; 17:815-26. [PMID: 20237510 DOI: 10.1038/gt.2010.29] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
To test whether fast-acting, self-complimentary (sc), adeno-associated virus-mediated RPE65 expression prevents cone degeneration and/or restores cone function, we studied two mouse lines: the Rpe65-deficient rd12 mouse and the Rpe65-deficient, rhodopsin null ('that is, cone function-only') Rpe65(-/-)::Rho(-/-) mouse. scAAV5 expressing RPE65 was injected subretinally into one eye of rd12 and Rpe65(-/-)::Rho(-/-) mice at postnatal day 14 (P14). Contralateral rd12 eyes were injected later, at P35. Rd12 behavioral testing revealed that rod vision loss was prevented with either P14 or P35 treatment, whereas cone vision was only detected after P14 treatment. Consistent with this observation, P35 treatment only restored rod electroretinogram (ERG) signals, a result likely due to reduced cone densities at this time point. For Rpe65(-/-)::Rho(-/-) mice in which there is no confounding rod contribution to the ERG signal, cone cells and cone-mediated ERGs were also maintained with treatment at P14. This work establishes that a self-complimentary AAV5 vector can restore substantial visual function in two genetically distinct models of Rpe65 deficiency within 4 days of treatment. In addition, this therapy prevents cone degeneration but only if administered before extensive cone degeneration, thus supporting continuation of current Leber's congenital amaurosis-2 clinical trials with an added emphasis on cone subtype analysis and early intervention.
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Affiliation(s)
- J Pang
- Department of Ophthalmology and Powell Gene Therapy Center, University of Florida, Gainesville, FL 32610, USA.
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