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Minella AL, Narfström Wiechel K, Petersen-Jones SM. Alternative splicing in CEP290 mutant cats results in a milder phenotype than LCA CEP290 patients. Vet Ophthalmol 2023; 26:4-11. [PMID: 36495011 PMCID: PMC10107307 DOI: 10.1111/vop.13052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/28/2022] [Accepted: 12/02/2022] [Indexed: 12/14/2022]
Abstract
PURPOSE The rdAc cat has an intronic mutation in the centrosomal 290 kDa (CEP290) gene resulting in a frameshift and a premature stop codon (c.6960 + 9 T > G, p.Ile2321AlafsTer3) predicted to truncate the protein by 157 amino acids. CEP290 mutations in human patients cause a range or phenotypes including syndromic conditions and severe childhood loss of vision while the rdAc cat has a milder phenotype. We sought to further characterize the effect of rdAc mutation on CEP290 expression. METHODS TaqMan quantitative real-time polymerase chain reaction assays were used to compare wildtype and truncated transcript levels. Relative protein abundance was analyzed by Western blot. Immunohistochemistry (IHC) was performed to detect CEP290 protein. RESULTS CEP290 mutant cats show low-level (17.4% of wildtype cats) use of the wildtype splice site and usage of the mutant splice site. Western analysis shows retina from cats homozygous for the mutation has CEP290 protein that likely comprises a combination of both wildtype and truncated protein. IHC detects CEP290 in affected and control retina labeling the region of the interconnecting cilium. CONCLUSIONS The comparably milder phenotype of CEP290 mutant cats is likely due to the retained production of some full-length CEP290 protein with possible functional contributions from presence of truncated protein.
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Affiliation(s)
- Andrea L Minella
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
| | - Kristina Narfström Wiechel
- Department of Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, Mssouri, USA
| | - Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA
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Schnichels S, Kiebler T, Hurst J, Maliha AM, Löscher M, Dick HB, Bartz-Schmidt KU, Joachim SC. Retinal Organ Cultures as Alternative Research Models. Altern Lab Anim 2019; 47:19-29. [DOI: 10.1177/0261192919840092] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Ex vivo organ cultures represent unique research models, as they combine the advantages of cell cultures with those of animal models. Being able to mimic in vivo situations through the use of organ cultures provides an excellent opportunity to investigate cellular processes, molecular pathways and cell–cell interactions, as well as structural and synaptic organisation. Human and animal organ cultures are now well established and comprise sensitive, easy-to-manipulate experimental systems that raise minimal ethical concerns. The eye, in particular, is a very complex organ that is not easy to reproduce in vitro. However, a lot of research has been dedicated to the development of suitable ocular organ cultures. This review covers the various ex vivo retinal organ culture systems available for use in ophthalmology research and compares them with commonly used animal models. In particular, bovine and porcine retinal organ culture systems are described, because the size, anatomy, physiology and vessel morphology of bovine and porcine eyes are similar to the human eye in an undisputed way, thus making them good models. In addition, these animals are widely used by the food industry and the eyes are considered surplus material. A short overview of murine, rat, rabbit, cat, canine and simian retinal organ cultures is also provided.
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Affiliation(s)
- Sven Schnichels
- Centre for Ophthalmology, University Eye Hospital Tübingen, Tübingen, Germany
| | - Tobias Kiebler
- Centre for Ophthalmology, University Eye Hospital Tübingen, Tübingen, Germany
| | - José Hurst
- Centre for Ophthalmology, University Eye Hospital Tübingen, Tübingen, Germany
| | - Ana M. Maliha
- Experimental Eye Research, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Marina Löscher
- Centre for Ophthalmology, University Eye Hospital Tübingen, Tübingen, Germany
| | - H. Burkhard Dick
- Experimental Eye Research, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
| | | | - Stephanie C. Joachim
- Experimental Eye Research, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
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Petit L, Ma S, Cheng SY, Gao G, Punzo C. Rod Outer Segment Development Influences AAV-Mediated Photoreceptor Transduction After Subretinal Injection. Hum Gene Ther 2018; 28:464-481. [PMID: 28510482 PMCID: PMC5488363 DOI: 10.1089/hum.2017.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Vectors based on the adeno-associated virus (AAV) are currently the preferred tools for delivering genes to photoreceptors (PR) in small and large animals. AAVs have been applied successfully in various models of PR dystrophies. However, unknown barriers still limit AAV's efficient application in several forms of severe PR degenerations due to insufficient transgene expression and/or treated cells at the time of injection. Optimizations of PR gene therapy strategies will likely benefit from the identification of the cellular factors that influence PR transduction. Interestingly, recent studies have shown that the AAV transduction profile of PRs differs significantly between neonatal and adult mouse retinas after subretinal injection. This phenomenon may provide clues to identify host factors that influence the efficiency of AAV-mediated PR transduction. This study demonstrates that rod outer segments are critical modulators of efficient AAV-mediated rod transduction. During retinal development, rod transduction correlated temporally and spatially with the differentiation order of PRs when vectors were introduced subretinally but not when introduced intravitreally. All subretinally injected vectors had an initial preference to transduce cones in the absence of formed rod outer segments and then displayed a preference for rods as the cells matured, independently of the expression cassette or AAV serotype. Consistent with this observation, altered development of rod outer segments was associated with a strong reduction of rod transduction and an increase in the percentage of transduced cones by 2- to 2.8-fold. A similar increase of cone transduction was observed in the adult retinal degeneration 1 (rd1) retina compared to wild-type mice. These results suggest that the loss of rod outer segments in diseased retinas could markedly affect gene transfer efficiency of AAV vectors by limiting the ability of AAVs to infect dying rods efficiently. This information could be exploited for the development of more efficient AAV-based PR gene delivery procedures.
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Affiliation(s)
- Lolita Petit
- 1 Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School , Worcester, Massachusetts
| | - Shan Ma
- 1 Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School , Worcester, Massachusetts
| | - Shun-Yun Cheng
- 1 Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School , Worcester, Massachusetts
| | - Guangping Gao
- 3 Department of Microbiology and Physiological Systems and Gene Therapy Center, 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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Zhang W, Li L, Su Q, Gao G, Khanna H. Gene Therapy Using a miniCEP290 Fragment Delays Photoreceptor Degeneration in a Mouse Model of Leber Congenital Amaurosis. Hum Gene Ther 2018; 29:42-50. [PMID: 28679290 PMCID: PMC5770090 DOI: 10.1089/hum.2017.049] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 06/27/2017] [Indexed: 12/25/2022] Open
Abstract
Mutations in the cilia-centrosomal protein CEP290 are frequently observed in autosomal recessive childhood blindness disorder Leber congenital amaurosis (LCA). No treatment or cure currently exists for this disorder. The Cep290rd16 (retinal degeneration 16) mouse (a model of LCA) carries a mutation in the Cep290 gene. This mutation leads to shorter cilia formation and defective photoreceptor structure and function. A roadblock to developing a gene replacement strategy for CEP290 using conventional adeno-associated virus (AAV) vectors is its large size. The identification and characterization is reported of a miniCEP290 gene that is amenable to AAV2/8-mediated delivery and delaying retinal degeneration in the Cep290rd16 mice. Using the ability of Cep290rd16 mouse embryonic fibroblasts to from shorter cilia as a platform, a human CEP290 domain encoded by amino acids 580-1180 (miniCEP290580-1180) was identified that can recover the cilia length in vitro. Furthermore, subretinal injection of AAV particles carrying the cDNA expressing miniCEP290580-1180 into neonatal Cep290rd16 mice resulted in significantly improved photoreceptor survival, morphology, and function compared to control injected mice. These studies show the potential of using a truncated CEP290 to treat this fast progressing and devastating disease.
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Affiliation(s)
- Wei Zhang
- Department of Ophthalmology, UMASS Medical School, Worcester, Massachusetts
| | - Linjing Li
- Department of Ophthalmology, UMASS Medical School, Worcester, Massachusetts
| | - Qin Su
- Horae Gene Therapy Center, UMASS Medical School, Worcester, Massachusetts
| | - Guangping Gao
- Horae Gene Therapy Center, UMASS Medical School, Worcester, Massachusetts
| | - Hemant Khanna
- Department of Ophthalmology, UMASS Medical School, Worcester, Massachusetts
- Horae Gene Therapy Center, UMASS Medical School, Worcester, Massachusetts
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Gupta PR, Huckfeldt RM. Gene therapy for inherited retinal degenerations: initial successes and future challenges. J Neural Eng 2017; 14:051002. [DOI: 10.1088/1741-2552/aa7a27] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Boyd RF, Boye SL, Conlon TJ, Erger KE, Sledge DG, Langohr IM, Hauswirth WW, Komáromy AM, Boye SE, Petersen-Jones SM, Bartoe JT. Reduced retinal transduction and enhanced transgene-directed immunogenicity with intravitreal delivery of rAAV following posterior vitrectomy in dogs. Gene Ther 2016; 23:548-56. [PMID: 27052802 DOI: 10.1038/gt.2016.31] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 02/19/2016] [Accepted: 02/29/2016] [Indexed: 12/22/2022]
Abstract
Adeno-associated virus (AAV) vector-based gene therapy is a promising treatment strategy for delivery of neurotrophic transgenes to retinal ganglion cells (RGCs) in glaucoma patients. Retinal distribution of transgene expression following intravitreal injection (IVT) of AAV is variable in animal models and the vitreous humor may represent a barrier to initial vector penetration. The primary goal of our study was to investigate the effect of prior core vitrectomy with posterior hyaloid membrane peeling on pattern and efficiency of transduction of a capsid amino acid substituted AAV2 vector, carrying the green fluorescent protein (GFP) reporter transgene following IVT in dogs. When progressive intraocular inflammation developed starting 4 weeks post IVT, the study plan was modified to allow detailed characterization of the etiology as a secondary goal. Unexpectedly, surgical vitrectomy was found to significantly limit transduction, whereas in non-vitrectomized eyes transduction efficiency reached upwards to 37.3% of RGC layer cells. The developing retinitis was characterized by mononuclear cell infiltrates resulting from a delayed-type hypersensitivity reaction, which we suspect was directed at the GFP transgene. Our results, in a canine large animal model, support caution when considering surgical vitrectomy before IVT for retinal gene therapy in patients, as prior vitrectomy appears to significantly reduce transduction efficiency and may predispose the patient to development of vector-induced immune reactions.
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Affiliation(s)
- R F Boyd
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
| | - S L Boye
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA
| | - T J Conlon
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, USA
| | - K E Erger
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, USA
| | - D G Sledge
- Diagnostic Center for Population and Animal Health, Michigan State University, East Lansing, MI, USA
| | - I M Langohr
- Diagnostic Center for Population and Animal Health, Michigan State University, East Lansing, MI, USA
| | - W W Hauswirth
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA
| | - A M Komáromy
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
| | - S E Boye
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA
| | - S M Petersen-Jones
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
| | - J T Bartoe
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
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The pros and cons of vertebrate animal models for functional and therapeutic research on inherited retinal dystrophies. Prog Retin Eye Res 2015; 48:137-59. [DOI: 10.1016/j.preteyeres.2015.04.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 04/12/2015] [Accepted: 04/16/2015] [Indexed: 01/19/2023]
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