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Xue Y, Zhou Y, Cepko CL. Txnip deletions and missense alleles prolong the survival of cones in a retinitis pigmentosa mouse model. eLife 2024; 12:RP90749. [PMID: 38727583 PMCID: PMC11087050 DOI: 10.7554/elife.90749] [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] [Indexed: 05/12/2024] Open
Abstract
Retinitis pigmentosa (RP) is an inherited retinal disease in which there is a loss of cone-mediated daylight vision. As there are >100 disease genes, our goal is to preserve cone vision in a disease gene-agnostic manner. Previously we showed that overexpressing TXNIP, an α-arrestin protein, prolonged cone vision in RP mouse models, using an AAV to express it only in cones. Here, we expressed different alleles of Txnip in the retinal pigmented epithelium (RPE), a support layer for cones. Our goal was to learn more of TXNIP's structure-function relationships for cone survival, as well as determine the optimal cell type expression pattern for cone survival. The C-terminal half of TXNIP was found to be sufficient to remove GLUT1 from the cell surface, and improved RP cone survival, when expressed in the RPE, but not in cones. Knock-down of HSP90AB1, a TXNIP-interactor which regulates metabolism, improved the survival of cones alone and was additive for cone survival when combined with TXNIP. From these and other results, it is likely that TXNIP interacts with several proteins in the RPE to indirectly support cone survival, with some of these interactions different from those that lead to cone survival when expressed only in cones.
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Affiliation(s)
- Yunlu Xue
- Departments of Genetics and Ophthalmology, Blavatnik Institute, Harvard Medical SchoolBostonUnited States
- Lingang LaboratoryShanghaiChina
| | - Yimin Zhou
- Lingang LaboratoryShanghaiChina
- School of Life Science and Technology, ShanghaiTech UniversityShanghaiChina
| | - Constance L Cepko
- Departments of Genetics and Ophthalmology, Blavatnik Institute, Harvard Medical SchoolBostonUnited States
- Howard Hughes Medical InstituteBostonUnited States
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Xue Y, Zhou Y, Cepko CL. Txnip deletions and missense alleles prolong the survival of cones in a retinitis pigmentosa mouse model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.03.551766. [PMID: 38370727 PMCID: PMC10871187 DOI: 10.1101/2023.08.03.551766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Retinitis pigmentosa (RP) is a prevalent inherited retinal degenerative disease worldwide, affecting 1 in 4,000 people. The disease is characterized by an initial loss of night vision followed by a loss of daylight and color vision. Many of the RP disease genes are expressed in the rod photoreceptors, the cell type that initiates dim light vision. Following loss of rods, the cone photoreceptors, which initiate daylight vision, also are affected and can die leading to total loss of vision. The reasons for loss of cone vision are not entirely clear, but appear to be due to loss of the rods. Previously we showed that overexpressing Txnip, an α-arrestin protein, in mouse models of RP using AAV gene therapy prolonged the survival of RP cones (Xue et al., 2021). At least part of the mechanism for cone survival was a switch in the fuel source, from glucose to lactate. In addition, the mitochondria of cones were both morphologically and functionally improved by delivery of Txnip. We have gone on to test several alleles of Txnip for the ability to prolong cone survival in rd1, a mouse model of RP. In addition, proteins that bind to Txnip and/or have homology to Txnip were tested. Five different deletion alleles of Txnip were expressed in cones or the retinal pigmented epithelium (RPE). Here we show that the C-terminal half of Txnip (149-397aa) is sufficient to remove GLUT1 from the RPE cell surface, and improved rd1 cone survival when expressed specifically in the RPE. Overexpressing Arrdc4, an α-arrestin that shares 60% similar protein sequence to Txnip, reduced rd1 cone survival. Reduction of the expression of HSP90AB1, a protein that interacts with Txnip and regulates metabolism, improved the survival of rd1 cones alone and was additive for cone survival when combined with Txnip. However, full length Txnip with a single amino acid change, C247S, as we tested in our original study, remains the most highly efficacious form of the gene for cone rescue. The above observations suggest that only a subset of the hypothesized and known activities of Txnip play a role in promoting RP cone survival, and that the activities of Txnip in the RPE differ from those in cone photoreceptors.
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Affiliation(s)
- Yunlu Xue
- Departments of Genetics and Ophthalmology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
- Lingang Laboratory, Shanghai, China, 200031
| | - Yimin Zhou
- Lingang Laboratory, Shanghai, China, 200031
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China, 201210
| | - Constance L. Cepko
- Departments of Genetics and Ophthalmology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
- Howard Hughes Medical Institute, Boston, MA 02115
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Loss of αA or αB-Crystallin Accelerates Photoreceptor Cell Death in a Mouse Model of P23H Autosomal Dominant Retinitis Pigmentosa. Int J Mol Sci 2021; 23:ijms23010070. [PMID: 35008496 PMCID: PMC8744961 DOI: 10.3390/ijms23010070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 02/08/2023] Open
Abstract
Inherited retinal degenerations (IRD) are a leading cause of visual impairment and can result from mutations in any one of a multitude of genes. Mutations in the light-sensing protein rhodopsin (RHO) is a leading cause of IRD with the most common of those being a missense mutation that results in substitution of proline-23 with histidine. This variant, also known as P23H-RHO, results in rhodopsin misfolding, initiation of endoplasmic reticulum stress, the unfolded protein response, and activation of cell death pathways. In this study, we investigate the effect of α-crystallins on photoreceptor survival in a mouse model of IRD secondary to P23H-RHO. We find that knockout of either αA- or αB-crystallin results in increased intraretinal inflammation, activation of apoptosis and necroptosis, and photoreceptor death. Our data suggest an important role for the ⍺-crystallins in regulating photoreceptor survival in the P23H-RHO mouse model of IRD.
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Roberts PA. Mathematical Models of Retinitis Pigmentosa: The Trophic Factor Hypothesis. J Theor Biol 2021; 534:110938. [PMID: 34687673 DOI: 10.1016/j.jtbi.2021.110938] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 10/02/2021] [Accepted: 10/04/2021] [Indexed: 10/20/2022]
Abstract
Retinitis pigmentosa (RP) is the term used to denote a group of inherited retinal-degenerative conditions that cause progressive sight loss. Individuals with this condition lose their light-sensitive photoreceptor cells, known as rods and cones, over a period of years to decades; degeneration starting in the retinal periphery, and spreading peripherally and centrally over time. RP is a rod-cone dystrophy, meaning that rod health and function are affected earlier and more severely than that of cones. Rods degenerate due to an underlying mutation, whereas the reasons for cone degeneration are unknown. A number of mechanisms have been proposed to explain secondary cone loss and the spatio-temporal patterns of retinal degeneration in RP. One of the most promising is the trophic factor hypothesis, which suggests that rods produce a factor necessary for cone survival, such that, when rods degenerate, cone degeneration follows. In this paper we formulate and analyse mathematical models of human RP under the trophic factor hypothesis. These models are constructed as systems of reaction-diffusion partial differential equations in one spatial dimension, and are solved and analysed using a combination of numerical and analytical methods. We predict the conditions under which cones will degenerate following the loss of a patch of rods from the retina, the critical trophic factor treatment rate required to prevent cone degeneration following rod loss and the spatio-temporal patterns of cone loss that would result if the trophic factor mechanism alone were responsible for retinal degeneration.
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Affiliation(s)
- Paul A Roberts
- School of Life Sciences, University of Sussex, John Maynard Smith Building, Brighton BN1 9QG, UK.
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Vargas A, Yamamoto KL, Craft CM, Lee EJ. Clusterin enhances cell survival by suppressing neuronal nitric-oxide synthase expression in the rhodopsin S334ter-line3 retinitis pigmentosa model. Brain Res 2021; 1768:147575. [PMID: 34242654 DOI: 10.1016/j.brainres.2021.147575] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 06/20/2021] [Accepted: 06/26/2021] [Indexed: 11/18/2022]
Abstract
Environmental changes in the retina, including oxidative stress-induced cell death, influence photoreceptor degeneration in Retinitis Pigmentosa (RP). Previously, we tested and discovered that a cytoprotective chaperone protein, clusterin, produced robust preservation of rod photoreceptors of a rat autosomal dominant rhodopsin transgenic model of RP, S334ter-line3. To investigate the biochemical and molecular cytoprotective pathways of clusterin, we examined and compared a known source of cone cell death, nitric oxide (NO), observing nNOS expression using antibody against nNOS in RP retinas with intravitreal injections of saline, clusterin (10 μg/ml), or a non-isoform-selective NOS inhibitor (25 mM), L-NAME, or with an intraperitoneal injection (IP) of L-NAME (100 mg/kg). Rhodopsin-immunoreactive rod photoreceptor cells and nNOS-immunoreactive cells were quantified with immunohistochemistry in the presence or absence of L-NAME or clusterin, and the total nNOS retinal expression was determined by immunoblot analysis. In this study, the level of nNOS expression was significantly up-regulated postnatally (P) at P15 (P < 0.05), P30 (P < 0.001) and P60 (P < 0.0001) in RP retinas compared to normal controls. Clusterin treatment suppressed the up-regulated nNOS expression in RP retinas (P < 0.0001) and was enhanced in Type II amacrine cells. Additionally, IP injection of L-NAME at P15 prolonged rod survival in the later stage of RP retinas (P < 0.001). Conversely, rod survival in L-NAME-treated RP retinas was not equivalent to the rod survival number seen in clusterin-treated retinas, which suggests induction of nNOS expression in RP retinas and its reduction by clusterin is only partly responsible for the rescue observed through the reduction of nNOS expression in S334ter-line3 rat retinas.
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Affiliation(s)
- Andrew Vargas
- Mary D. Allen Vision Research Laboratory, USC Roski Eye Institute, Department of Ophthalmology, Los Angeles, CA, United States
| | - Kyra L Yamamoto
- Mary D. Allen Vision Research Laboratory, USC Roski Eye Institute, Department of Ophthalmology, Los Angeles, CA, United States
| | - Cheryl Mae Craft
- Mary D. Allen Vision Research Laboratory, USC Roski Eye Institute, Department of Ophthalmology, Los Angeles, CA, United States; Department of Integrative Anatomical Sciences, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States
| | - Eun-Jin Lee
- Mary D. Allen Vision Research Laboratory, USC Roski Eye Institute, Department of Ophthalmology, Los Angeles, CA, United States; Department of Ophthalmology, Stanford University, Palo Alto, CA, United States; VA Palo Alto Healthcare System, Palo Alto, CA, United States; Department of Pathology, Stanford University, Palo Alto, CA, United States.
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Krueger K, Boehme E, Klettner AK, Zille M. The potential of marine resources for retinal diseases: a systematic review of the molecular mechanisms. Crit Rev Food Sci Nutr 2021; 62:7518-7560. [PMID: 33970706 DOI: 10.1080/10408398.2021.1915242] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We rely on vision more than on any other sense to obtain information about our environment. Hence, the loss or even impairment of vision profoundly affects our quality of life. Diet or food components have already demonstrated beneficial effects on the development of retinal diseases. Recently, there has been a growing interest in resources from marine animals and plants for the prevention of retinal diseases through nutrition. Especially fish intake and omega-3 fatty acids have already led to promising results, including associations with a reduced incidence of retinal diseases. However, the underlying molecular mechanisms are insufficiently explained. The aim of this review was to summarize the known mechanistic effects of marine resources on the pathophysiological processes in retinal diseases. We performed a systematic literature review following the PRISMA guidelines and identified 107 studies investigating marine resources in the context of retinal diseases. Of these, 46 studies described the underlying mechanisms including anti-inflammatory, antioxidant, antiangiogenic/vasoprotective, cytoprotective, metabolic, and retinal function effects, which we critically summarize. We further discuss perspectives on the use of marine resources for human nutrition to prevent retinal diseases with a particular focus on regulatory aspects, health claims, safety, and bioavailability.
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Affiliation(s)
- Kristin Krueger
- Department of Marine Biotechnology, Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, Lübeck, Germany
| | - Elke Boehme
- Department of Marine Biotechnology, Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, Lübeck, Germany
| | - Alexa Karina Klettner
- Department of Ophthalmology, University Medical Center, University of Kiel, Quincke Research Center, Kiel, Germany
| | - Marietta Zille
- Department of Marine Biotechnology, Fraunhofer Research and Development Center for Marine and Cellular Biotechnology EMB, Lübeck, Germany.,Institute for Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany
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Di Pierdomenico J, Martínez-Vacas A, Hernández-Muñoz D, Gómez-Ramírez AM, Valiente-Soriano FJ, Agudo-Barriuso M, Vidal-Sanz M, Villegas-Pérez MP, García-Ayuso D. Coordinated Intervention of Microglial and Müller Cells in Light-Induced Retinal Degeneration. Invest Ophthalmol Vis Sci 2020; 61:47. [PMID: 32232352 PMCID: PMC7401701 DOI: 10.1167/iovs.61.3.47] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Purpose To analyze the role of microglial and Müller cells in the formation of rings of photoreceptor degeneration caused by phototoxicity. Methods Two-month-old Sprague-Dawley rats were exposed to light and processed 1, 2, or 3 months later. Retinas were dissected as whole-mounts, immunodetected for microglial cells, Müller cells, and S- and L/M-cones and analyzed using fluorescence, thunder imaging, and confocal microscopy. Cone populations were automatically counted and isodensity maps constructed to document cone topography. Results Phototoxicity causes a significant progressive loss of S- and L/M-cones of up to 68% and 44%, respectively, at 3 months after light exposure (ALE). One month ALE, we observed rings of cone degeneration in the photosensitive area of the superior retina. Two and 3 months ALE, these rings had extended to the central and inferior retina. Within the rings of cone degeneration, there were degenerating cones, often activated microglial cells, and numerous radially oriented processes of Müller cells that showed increased expression of intermediate filaments. Between 1 and 3 months ALE, the rings coalesced, and at the same time the microglial cells resumed a mosaic-like distribution, and there was a decrease of Müller cell gliosis at the areas devoid of cones. Conclusions Light-induced photoreceptor degeneration proceeds with rings of cone degeneration, as observed in inherited retinal degenerations in which cone death is secondary to rod degeneration. The spatiotemporal relationship of cone death microglial cell activation and Müller cell gliosis within the rings of cone degeneration suggests that, although both glial cells are involved in the formation of the rings, they may have coordinated actions and, while microglial cells may be more involved in photoreceptor phagocytosis, Müller cells may be more involved in cone and microglial cell migration, retinal remodeling and glial seal formation.
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Early detection of cone photoreceptor cell loss in retinitis pigmentosa using adaptive optics scanning laser ophthalmoscopy. Graefes Arch Clin Exp Ophthalmol 2019; 257:1169-1181. [DOI: 10.1007/s00417-019-04307-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 02/18/2019] [Accepted: 03/21/2019] [Indexed: 10/27/2022] Open
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McLelland BT, Lin B, Mathur A, Aramant RB, Thomas BB, Nistor G, Keirstead HS, Seiler MJ. Transplanted hESC-Derived Retina Organoid Sheets Differentiate, Integrate, and Improve Visual Function in Retinal Degenerate Rats. Invest Ophthalmol Vis Sci 2019; 59:2586-2603. [PMID: 29847666 PMCID: PMC5968836 DOI: 10.1167/iovs.17-23646] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Purpose To investigate whether sheets of retina organoids derived from human embryonic stem cells (hESCs) can differentiate, integrate, and improve visual function in an immunodeficient rat model of severe retinal degeneration (RD). Methods 3D hESC-derived retina organoids were analyzed by quantitative PCR and immunofluorescence. Sheets dissected from retina organoids (30–65 days of differentiation) were transplanted into the subretinal space of immunodeficient rho S334ter-3 rats. Visual function was tested by optokinetic testing and electrophysiologic recording in the superior colliculus. Transplants were analyzed at 54 to 300 days postsurgery by immunohistochemistry for donor and retinal markers. Results Retina organoids contained multiple retinal cell types, including progenitor populations capable of developing new cones and rods. After transplantation into an immunodeficient rat model of severe RD, the transplanted sheets differentiated, integrated, and produced functional photoreceptors and other retinal cells, according to the longer human developmental timetable. Maturation of the transplanted retinal cells created visual improvements that were measured by optokinetic testing and electrophysiologic recording in the superior colliculus. Immunohistochemistry analysis indicated that the donor cells were synaptically active. Extensive transplant projections could be seen within the host RD retina. Optical coherence tomography imaging monitored long-term transplant growth and survival up to 10 months postsurgery. Conclusions These data demonstrate that the transplantation of sheets dissected from hESC-derived retina organoids is a potential therapeutic method for restoring vision in advanced stages of RD.
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Affiliation(s)
- Bryce T McLelland
- Physical Medicine & Rehabilitation, Sue & Bill Gross Stem Cell Research Center, University of California Irvine, School of Medicine, Irvine, California, United States
| | - Bin Lin
- Physical Medicine & Rehabilitation, Sue & Bill Gross Stem Cell Research Center, University of California Irvine, School of Medicine, Irvine, California, United States
| | - Anuradha Mathur
- Physical Medicine & Rehabilitation, Sue & Bill Gross Stem Cell Research Center, University of California Irvine, School of Medicine, Irvine, California, United States
| | - Robert B Aramant
- Physical Medicine & Rehabilitation, Sue & Bill Gross Stem Cell Research Center, University of California Irvine, School of Medicine, Irvine, California, United States
| | - Biju B Thomas
- University of Southern California Roski Eye Institute, Department of Ophthalmology, University of Southern California, Los Angeles, California, United States
| | - Gabriel Nistor
- AIVITA Biomedical, Inc., Irvine, California, United States
| | | | - Magdalene J Seiler
- Physical Medicine & Rehabilitation, Sue & Bill Gross Stem Cell Research Center, University of California Irvine, School of Medicine, Irvine, California, United States
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Detailed Visual Cortical Responses Generated by Retinal Sheet Transplants in Rats with Severe Retinal Degeneration. J Neurosci 2018; 38:10709-10724. [PMID: 30396913 DOI: 10.1523/jneurosci.1279-18.2018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 10/18/2018] [Accepted: 10/21/2018] [Indexed: 11/21/2022] Open
Abstract
To combat retinal degeneration, healthy fetal retinal sheets have been successfully transplanted into both rodent models and humans, with synaptic connectivity between transplant and degenerated host retina having been confirmed. In rodent studies, transplants have been shown to restore responses to flashes of light in a region of the superior colliculus corresponding to the location of the transplant in the host retina. To determine the quality and detail of visual information provided by the transplant, visual responsivity was studied here at the level of visual cortex where higher visual perception is processed. For our model, we used the transgenic Rho-S334ter line-3 rat (both sexes), which loses photoreceptors at an early age and is effectively blind at postnatal day 30. These rats received fetal retinal sheet transplants in one eye between 24 and 40 d of age. Three to 10 months following surgery, visually responsive neurons were found in regions of primary visual cortex matching the transplanted region of the retina that were as highly selective as normal rat to stimulus orientation, size, contrast, and spatial and temporal frequencies. Conversely, we found that selective response properties were largely absent in nontransplanted line-3 rats. Our data show that fetal retinal sheet transplants can result in remarkably normal visual function in visual cortex of rats with a degenerated host retina and represents a critical step toward developing an effective remedy for the visually impaired human population.SIGNIFICANCE STATEMENT Age-related macular degeneration and retinitis pigmentosa lead to profound vision loss in millions of people worldwide. Many patients lose both retinal pigment epithelium and photoreceptors. Hence, there is a great demand for the development of efficient techniques that allow for long-term vision restoration. In this study, we transplanted dissected fetal retinal sheets, which can differentiate into photoreceptors and integrate with the host retina of rats with severe retinal degeneration. Remarkably, we show that transplants generated visual responses in cortex similar in quality to normal rats. Furthermore, transplants preserved connectivity within visual cortex and the retinal relay from the lateral geniculate nucleus to visual cortex, supporting their potential application in curing vision loss associated with retinal degeneration.
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Thomas BB, Zhu D, Lin TC, Kim YC, Seiler MJ, Martinez-Camarillo JC, Lin B, Shad Y, Hinton DR, Humayun MS. A new immunodeficient retinal dystrophic rat model for transplantation studies using human-derived cells. Graefes Arch Clin Exp Ophthalmol 2018; 256:2113-2125. [PMID: 30215097 DOI: 10.1007/s00417-018-4134-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 08/28/2018] [Accepted: 09/03/2018] [Indexed: 12/11/2022] Open
Abstract
PURPOSE To create new immunodeficient Royal College of Surgeons (RCS) rats by introducing the defective MerTK gene into athymic nude rats. METHODS Female homozygous RCS (RCS-p+/RCS-p+) and male nude rats (Hsd:RH-Foxn1mu, mutation in the foxn1 gene; no T cells) were crossed to produce heterozygous F1 progeny. Double homozygous F2 progeny obtained by crossing the F1 heterozygotes was identified phenotypically (hair loss) and genotypically (RCS-p+ gene determined by PCR). Retinal degenerative status was confirmed by optical coherence tomography (OCT) imaging, electroretinography (ERG), optokinetic (OKN) testing, superior colliculus (SC) electrophysiology, and by histology. The effect of xenografts was assessed by transplantation of human embryonic stem cell-derived retinal pigment epithelium (hESC-RPE) and human-induced pluripotent stem cell-derived RPE (iPS-RPE) into the eye. Morphological analysis was conducted based on hematoxylin and eosin (H&E) and immunostaining. Age-matched pigmented athymic nude rats were used as control. RESULTS Approximately 6% of the F2 pups (11/172) were homozygous for RCS-p+ gene and Foxn1mu gene. Homozygous males crossed with heterozygous females resulted in 50% homozygous progeny for experimentation. OCT imaging demonstrated significant loss of retinal thickness in homozygous rats. H&E staining showed photoreceptor thickness reduced to 1-3 layers at 12 weeks of age. Progressive loss of visual function was evidenced by OKN testing, ERG, and SC electrophysiology. Transplantation experiments demonstrated survival of human-derived cells and absence of apparent immune rejection. CONCLUSIONS This new rat animal model developed by crossing RCS rats and athymic nude rats is suitable for conducting retinal transplantation experiments involving xenografts.
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Affiliation(s)
- Biju B Thomas
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, 90033, USA.
- USC Institute for Biomedical Therapeutics, University of Southern California, Los Angeles, CA, USA.
| | - Danhong Zhu
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, 90033, USA
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Tai-Chi Lin
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, 90033, USA
- USC Institute for Biomedical Therapeutics, University of Southern California, Los Angeles, CA, USA
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan, Republic of China
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Young Chang Kim
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, 90033, USA
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Magdalene J Seiler
- Department of Physical Medicine & Rehabilitation, University of California-Irvine, Irvine, CA, USA
- Stem Cell Research Center, University of California-Irvine, Irvine, CA, USA
| | - Juan Carlos Martinez-Camarillo
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, 90033, USA
- USC Institute for Biomedical Therapeutics, University of Southern California, Los Angeles, CA, USA
| | - Bin Lin
- Department of Physical Medicine & Rehabilitation, University of California-Irvine, Irvine, CA, USA
- Stem Cell Research Center, University of California-Irvine, Irvine, CA, USA
| | - Yousuf Shad
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON, Canada
| | - David R Hinton
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, 90033, USA
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Mark S Humayun
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, 90033, USA
- USC Institute for Biomedical Therapeutics, University of Southern California, Los Angeles, CA, USA
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McMurtrey JJ, Tso MOM. A review of the immunologic findings observed in retinitis pigmentosa. Surv Ophthalmol 2018; 63:769-781. [PMID: 29551596 DOI: 10.1016/j.survophthal.2018.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 03/12/2018] [Accepted: 03/12/2018] [Indexed: 12/20/2022]
Abstract
Most patients suffering from retinitis pigmentosa (RP) inherit the disorder; however, the immune-pathologic features associated with this disease have yet to be extensively studied. Six reports correlate antiretinal immune activity with vision deterioration in RP patients. Some of these patients have sporadic RP that occurs in excess of expected gene segregation during inheritance. The hypothesis that a primary immune-mediated disease process occurs in this sporadic group is supported by significant associations of RP with autoimmune endocrinopathies and other immune-related conditions or factors; however, no immunologic difference regarding RP family history is reported in the peripheral blood studies of RP patients. Twenty-one percent to 51% of RP patients display antiretinal antibodies, whereas 19-58% have antiretinal lymphocyte reactivity to retinal extract, and 60-85% have activated T cells. Mutations in animal models of RP have been shown to cause endoplasmic reticulum stress that may initiate immunopathology for genetic RP, but oxidative stress also encourages immune cytotoxicity. In addition, necrotic cell death is evident, which promotes inflammatory conditions. We review mechanisms and evidence for an occult inflammation in genetic RP and examine reports of efficacy in retarding RP progression with anti-inflammatory agents in clinical trials.
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Affiliation(s)
- John J McMurtrey
- The Wilmer Ophthalmological Institute, The Johns Hopkins University and Hospital, Baltimore, Maryland, USA.
| | - Mark O M Tso
- The Wilmer Ophthalmological Institute, The Johns Hopkins University and Hospital, Baltimore, Maryland, USA
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13
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LaVail MM, Nishikawa S, Steinberg RH, Naash MI, Duncan JL, Trautmann N, Matthes MT, Yasumura D, Lau-Villacorta C, Chen J, Peterson WM, Yang H, Flannery JG. Phenotypic characterization of P23H and S334ter rhodopsin transgenic rat models of inherited retinal degeneration. Exp Eye Res 2018; 167:56-90. [PMID: 29122605 PMCID: PMC5811379 DOI: 10.1016/j.exer.2017.10.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/25/2017] [Accepted: 10/31/2017] [Indexed: 02/07/2023]
Abstract
We produced 8 lines of transgenic (Tg) rats expressing one of two different rhodopsin mutations in albino Sprague-Dawley (SD) rats. Three lines were generated with a proline to histidine substitution at codon 23 (P23H), the most common autosomal dominant form of retinitis pigmentosa in the United States. Five lines were generated with a termination codon at position 334 (S334ter), resulting in a C-terminal truncated opsin protein lacking the last 15 amino acid residues and containing all of the phosphorylation sites involved in rhodopsin deactivation, as well as the terminal QVAPA residues important for rhodopsin deactivation and trafficking. The rates of photoreceptor (PR) degeneration in these models vary in proportion to the ratio of mutant to wild-type rhodopsin. The models have been widely studied, but many aspects of their phenotypes have not been described. Here we present a comprehensive study of the 8 Tg lines, including the time course of PR degeneration from the onset to one year of age, retinal structure by light and electron microscopy (EM), hemispheric asymmetry and gradients of rod and cone degeneration, rhodopsin content, gene dosage effect, rapid activation and invasion of the outer retina by presumptive microglia, rod outer segment disc shedding and phagocytosis by the retinal pigmented epithelium (RPE), and retinal function by the electroretinogram (ERG). The biphasic nature of PR cell death was noted, as was the lack of an injury-induced protective response in the rat models. EM analysis revealed the accumulation of submicron vesicular structures in the interphotoreceptor space during the peak period of PR outer segment degeneration in the S334ter lines. This is likely due to the elimination of the trafficking consensus domain as seen before as with other rhodopsin mutants lacking the C-terminal QVAPA. The 8 rhodopsin Tg lines have been, and will continue to be, extremely useful models for the experimental study of inherited retinal degenerations.
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Affiliation(s)
- Matthew M LaVail
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Shimpei Nishikawa
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Roy H Steinberg
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd., Room 2011, Houston, TX 77204-5060, USA.
| | - Jacque L Duncan
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Nikolaus Trautmann
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Michael T Matthes
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Douglas Yasumura
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA
| | - Cathy Lau-Villacorta
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Jeannie Chen
- Zilka Neurogenetic Institute, USC Keck School of Medicine, Los Angeles, CA 90089-2821, USA.
| | - Ward M Peterson
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Haidong Yang
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - John G Flannery
- School of Optometry, UC Berkeley, Berkeley, CA 94720-2020, USA.
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Assessment of Safety and Functional Efficacy of Stem Cell-Based Therapeutic Approaches Using Retinal Degenerative Animal Models. Stem Cells Int 2017; 2017:9428176. [PMID: 28928775 PMCID: PMC5592015 DOI: 10.1155/2017/9428176] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Accepted: 06/19/2017] [Indexed: 02/06/2023] Open
Abstract
Dysfunction and death of retinal pigment epithelium (RPE) and or photoreceptors can lead to irreversible vision loss. The eye represents an ideal microenvironment for stem cell-based therapy. It is considered an “immune privileged” site, and the number of cells needed for therapy is relatively low for the area of focused vision (macula). Further, surgical placement of stem cell-derived grafts (RPE, retinal progenitors, and photoreceptor precursors) into the vitreous cavity or subretinal space has been well established. For preclinical tests, assessments of stem cell-derived graft survival and functionality are conducted in animal models by various noninvasive approaches and imaging modalities. In vivo experiments conducted in animal models based on replacing photoreceptors and/or RPE cells have shown survival and functionality of the transplanted cells, rescue of the host retina, and improvement of visual function. Based on the positive results obtained from these animal experiments, human clinical trials are being initiated. Despite such progress in stem cell research, ethical, regulatory, safety, and technical difficulties still remain a challenge for the transformation of this technique into a standard clinical approach. In this review, the current status of preclinical safety and efficacy studies for retinal cell replacement therapies conducted in animal models will be discussed.
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Protective effect of clusterin on rod photoreceptor in rat model of retinitis pigmentosa. PLoS One 2017; 12:e0182389. [PMID: 28767729 PMCID: PMC5540409 DOI: 10.1371/journal.pone.0182389] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/17/2017] [Indexed: 01/09/2023] Open
Abstract
Retinitis Pigmentosa (RP) begins with the death of rod photoreceptors and is slowly followed by a gradual loss of cones and a rearrangement of the remaining retinal neurons. Clusterin is a chaperone protein that protects cells and is involved in various pathophysiological stresses, including retinal degeneration. Using a well-established transgenic rat model of RP (rhodopsin S334ter), we investigated the effects of clusterin on rod photoreceptor survival. To investigate the role of clusterin in S334ter-line3 retinas, Voronoi analysis and immunohistochemistry were used to evaluate the geometry of rod distribution. Additionally, immunoblot analysis, Bax activation, STAT3 and Akt phosphorylation were used to evaluate the pathway involved in rod cell protection. In this study, clusterin (10μg/ml) intravitreal treatment produced robust preservation of rod photoreceptors in S334ter-line3 retina. The mean number of rods in 1mm2 was significantly greater in clusterin injected RP retinas (postnatal (P) 30, P45, P60, & P75) than in age-matched saline injected RP retinas (P<0.01). Clusterin activated Akt, STAT3 and significantly reduced Bax activity; in addition to inducing phosphorylated STAT3 in Müller cells, which suggests it may indirectly acts on photoreceptors. Thus, clusterin treatment may interferes with mechanisms leading to rod death by suppressing cell death through activation of Akt and STAT3, followed by Bax suppression. Novel insights into the pathway of how clusterin promotes the rod cell survival suggest this treatment may be a potential therapeutic strategy to slow progression of vision loss in human RP.
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Roberts PA, Gaffney EA, Luthert PJ, Foss AJ, Byrne HM. Mathematical models of retinitis pigmentosa: The oxygen toxicity hypothesis. J Theor Biol 2017; 425:53-71. [DOI: 10.1016/j.jtbi.2017.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 04/29/2017] [Accepted: 05/03/2017] [Indexed: 01/31/2023]
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Yu WQ, Grzywacz NM, Lee EJ, Field GD. Cell type-specific changes in retinal ganglion cell function induced by rod death and cone reorganization in rats. J Neurophysiol 2017; 118:434-454. [PMID: 28424296 PMCID: PMC5506261 DOI: 10.1152/jn.00826.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 04/17/2017] [Accepted: 04/17/2017] [Indexed: 02/02/2023] Open
Abstract
We have determined the impact of rod death and cone reorganization on the spatiotemporal receptive fields (RFs) and spontaneous activity of distinct retinal ganglion cell (RGC) types. We compared RGC function between healthy and retinitis pigmentosa (RP) model rats (S334ter-3) at a time when nearly all rods were lost but cones remained. This allowed us to determine the impact of rod death on cone-mediated visual signaling, a relevant time point because the diagnosis of RP frequently occurs when patients are nightblind but daytime vision persists. Following rod death, functionally distinct RGC types persisted; this indicates that parallel processing of visual input remained largely intact. However, some properties of cone-mediated responses were altered ubiquitously across RGC types, such as prolonged temporal integration and reduced spatial RF area. Other properties changed in a cell type-specific manner, such as temporal RF shape (dynamics), spontaneous activity, and direction selectivity. These observations identify the extent of functional remodeling in the retina following rod death but before cone loss. They also indicate new potential challenges to restoring normal vision by replacing lost rod photoreceptors.NEW & NOTEWORTHY This study provides novel and therapeutically relevant insights to retinal function following rod death but before cone death. To determine changes in retinal output, we used a large-scale multielectrode array to simultaneously record from hundreds of retinal ganglion cells (RGCs). These recordings of large-scale neural activity revealed that following the death of all rods, functionally distinct RGCs remain. However, the receptive field properties and spontaneous activity of these RGCs are altered in a cell type-specific manner.
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Affiliation(s)
- Wan-Qing Yu
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California
| | - Norberto M Grzywacz
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California.,Department of Biomedical Engineering, University of Southern California, Los Angeles, California.,Department of Electrical Engineering, University of Southern California, Los Angeles, California.,Department of Neuroscience, Department of Physics, and Graduate School of Arts and Sciences, Georgetown University, Washington, District of Columbia
| | - Eun-Jin Lee
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California.,Mary D. Allen Laboratory for Vision Research, USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California; and
| | - Greg D Field
- Department of Neurobiology, Duke University School of Medicine, Durham, North Carolina
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Shin JA, Kim HS, Vargas A, Yu WQ, Eom YS, Craft CM, Lee EJ. Inhibition of Matrix Metalloproteinase 9 Enhances Rod Survival in the S334ter-line3 Retinitis Pigmentosa Model. PLoS One 2016; 11:e0167102. [PMID: 27893855 PMCID: PMC5125676 DOI: 10.1371/journal.pone.0167102] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/08/2016] [Indexed: 12/31/2022] Open
Abstract
Retinitis Pigmentosa (RP) is one of the most common forms of inherited visual loss with the initial degeneration of rod photoreceptors, followed by a progressive cone photoreceptor deterioration. Coinciding with this visual loss, the extracellular matrix (ECM) is reorganized, which alters matrix metalloproteinase (MMP) activity levels. A potential pathological role of MMPs, MMP-9 in particular, involves an excitotoxicity-mediated physiological response. In the current study, we examine the MMP-9 and MMP-2 expression levels in the rhodopsin S334ter-line3 RP rat model and investigate the impact of treatment with SB-3CT, a specific MMP-9 and MMP-2 inhibitor, on rod cell survival was tested. Retinal MMP-9 and MMP-2 expression levels were quantified by immunoblot analysis from S334ter-line3 rats compared to controls. Gelatinolytic activities of MMP-9 and MMP-2 by zymography were examined. The geometry of rod death was further evaluated using Voronoi analysis. Our results revealed that MMP-9 was elevated while MMP-2 was relatively unchanged when S334ter-line 3 retinas were compared to controls. With SB-3CT treatment, we observed gelatinolytic activity of both MMPs was decreased and diminished clustering associated with rod death, in addition to a robust preservation of rod photoreceptors. These results demonstrate that up-regulation of MMP-9 in retinas of S334ter-line3 are associated with rod death. The application of SB-3CT dramatically interferes with mechanisms leading to apoptosis in an MMP-9-dependent manner. Future studies will determine the feasibility of using SB-3CT as a potential therapeutic strategy to slow progression of vision loss in genetic inherited forms of human RP.
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Affiliation(s)
- Jung-A Shin
- Mary D. Allen Laboratory for Vision Research, USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
- Department of Anatomy, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Hwa Sun Kim
- Mary D. Allen Laboratory for Vision Research, USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
| | - Andrew Vargas
- Mary D. Allen Laboratory for Vision Research, USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
| | - Wan-Qing Yu
- Mary D. Allen Laboratory for Vision Research, USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
- Department of Biological Structure, University of Washington, Seattle, Washington, United States of America
| | - Yun Sung Eom
- Mary D. Allen Laboratory for Vision Research, USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
| | - Cheryl Mae Craft
- Mary D. Allen Laboratory for Vision Research, USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
- Department of Cell & Neurobiology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States of America
| | - Eun-Jin Lee
- Mary D. Allen Laboratory for Vision Research, USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
- Department of Biomedical Engineering, University of Southern California Viterbi School of Engineering, Los Angeles, California, United States of America
- * E-mail:
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Mathematical and computational models of the retina in health, development and disease. Prog Retin Eye Res 2016; 53:48-69. [PMID: 27063291 DOI: 10.1016/j.preteyeres.2016.04.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 04/05/2016] [Accepted: 04/05/2016] [Indexed: 12/12/2022]
Abstract
The retina confers upon us the gift of vision, enabling us to perceive the world in a manner unparalleled by any other tissue. Experimental and clinical studies have provided great insight into the physiology and biochemistry of the retina; however, there are questions which cannot be answered using these methods alone. Mathematical and computational techniques can provide complementary insight into this inherently complex and nonlinear system. They allow us to characterise and predict the behaviour of the retina, as well as to test hypotheses which are experimentally intractable. In this review, we survey some of the key theoretical models of the retina in the healthy, developmental and diseased states. The main insights derived from each of these modelling studies are highlighted, as are model predictions which have yet to be tested, and data which need to be gathered to inform future modelling work. Possible directions for future research are also discussed. Whilst the present modelling studies have achieved great success in unravelling the workings of the retina, they have yet to achieve their full potential. For this to happen, greater involvement with the modelling community is required, and stronger collaborations forged between experimentalists, clinicians and theoreticians. It is hoped that, in addition to bringing the fruits of current modelling studies to the attention of the ophthalmological community, this review will encourage many such future collaborations.
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Yu WQ, Eom YS, Shin JA, Nair D, Grzywacz SXZ, Grzywacz NM, Craft CM, Lee EJ. Reshaping the Cone-Mosaic in a Rat Model of Retinitis Pigmentosa: Modulatory Role of ZO-1 Expression in DL-Alpha-Aminoadipic Acid Reshaping. PLoS One 2016; 11:e0151668. [PMID: 26977812 PMCID: PMC4792433 DOI: 10.1371/journal.pone.0151668] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/02/2016] [Indexed: 01/21/2023] Open
Abstract
In S334ter-line-3 rat model of Retinitis Pigmentosa (RP), rod cell death induces the rearrangement of cones into mosaics of rings while the fibrotic processes of Müller cells remodel to fill the center of the rings. In contrast, previous work established that DL-alpha-aminoadipic-acid (AAA), a compound that transiently blocks Müller cell metabolism, abolishes these highly structured cone rings. Simultaneously, adherens-junction associated protein, Zonula occludens-1 (ZO-1) expression forms in a network between the photoreceptor segments and Müller cells processes. Thus, we hypothesized that AAA treatment alters the cone mosaic rings by disrupting the distal sealing formed by these fibrotic processes, either directly or indirectly, by down regulating the expression of ZO-1. Therefore, we examined these processes and ZO-1 expression at the outer retina after intravitreal injection of AAA and observed that AAA treatment transiently disrupts the distal glial sealing in RP retina, plus induces cones in rings to become more homogeneous. Moreover, ZO-1 expression is actively suppressed after 3 days of AAA treatment, which coincided with cone ring disruption. Similar modifications of glial sealing and cone distribution were observed after injection of siRNA to inhibit ZO-1 expression. These findings support our hypothesis and provide additional information about the critical role played by ZO-1 in glial sealing and shaping the ring mosaic in RP retina. These studies represent important advancements in the understanding of retinal degeneration's etiology and pathophysiology.
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Affiliation(s)
- Wan-Qing Yu
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States of America
- Department of Biological Structure, University of Washington, Seattle, United States of America
| | - Yun Sung Eom
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, University of Southern California, Los Angeles, California, United States of America
| | - Jung-A Shin
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, University of Southern California, Los Angeles, California, United States of America
- Department of Anatomy, School of Medicine, Ewha Womans University, Seoul, Korea
| | - Divya Nair
- Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, California, United States of America
| | - Sara X. Z. Grzywacz
- Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California, United States of America
| | - Norberto M. Grzywacz
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States of America
- Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, California, United States of America
- Department of Neuroscience, Georgetown University, Washington D.C., United States of America
- Department of Physics, Georgetown University, Washington D.C., United States of America
| | - Cheryl Mae Craft
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States of America
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, University of Southern California, Los Angeles, California, United States of America
- Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- Department of Cell & Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Eun-Jin Lee
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, University of Southern California, Los Angeles, California, United States of America
- Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, California, United States of America
- Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
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Shin JA, Eom YS, Yu WQ, Grzywacz NM, Craft CM, Lee EJ. TIMP-1 affects the spatial distribution of dendritic processes of second-order neurons in a rat model of Retinitis Pigmentosa. Exp Eye Res 2015; 140:41-52. [PMID: 26277580 DOI: 10.1016/j.exer.2015.08.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 07/24/2015] [Accepted: 08/07/2015] [Indexed: 01/12/2023]
Abstract
Retinitis Pigmentosa (RP) is an inherited disorder that may lead to blindness. In the rhodopsin S334ter-line-3 rat model of RP, the death of rods induces spatial rearrangement of cones into regular ring mosaics. Using this model, we discovered that the ring mosaics are restored to a homogeneous distribution upon application of tissue inhibitor of metalloproteinase-1 (TIMP-1). In this study, we further investigated the cone migration and spatial distribution of second-order neurons and their connections to cones in the presence or absence of TIMP-1 using immunohistochemistry to identify retinal neurons and their connections with cones. M-opsin cell bodies and their outer segments were evaluated to determine whether TIMP-1 delays the degeneration of outer segments of cones. We observed that during cone rearrangement into ring mosaics in RP retina, dendritic processes of second-order neurons undergo remodeling to maintain their synaptic connections with the cones in the rings. TIMP-1 treatment induced the cones to rearrange and dendritic processes of second-order neurons to return to a more homogeneous spatial distribution. In addition, TIMP-1 treatment protected the outer segments of cones at later stages of retinal degeneration. Our findings clearly demonstrate that despite their dramatic spatial rearrangement, cones and second-order neuron processes maintain their synaptic connections before and after TIMP-1 treatment.
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Affiliation(s)
- Jung-A Shin
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Keck School of Medicine of the University of Southern California, USA; Department of Ophthalmology, Keck School of Medicine of the University of Southern California, USA; Department of Anatomy, School of Medicine, Ewha Womans University, Seoul 158-710, South Korea
| | - Yun Sung Eom
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Keck School of Medicine of the University of Southern California, USA; Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA, USA
| | - Wan-Qing Yu
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA
| | - Norberto M Grzywacz
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA; Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA, USA; University of Southern California Viterbi School of Engineering, Los Angeles, CA, USA; Department of Neuroscience, Georgetown University, Washington D.C, USA; Department of Physics, Georgetown University, Washington D.C, USA
| | - Cheryl Mae Craft
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Keck School of Medicine of the University of Southern California, USA; Department of Ophthalmology, Keck School of Medicine of the University of Southern California, USA; Department of Cell & Neurobiology, Keck School of Medicine of the University of Southern California, USA; Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA
| | - Eun-Jin Lee
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, Keck School of Medicine of the University of Southern California, USA; Department of Ophthalmology, Keck School of Medicine of the University of Southern California, USA; Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.
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Ji Y, Yu WQ, Eom YS, Bruce F, Craft CM, Grzywacz NM, Lee EJ. The effect of TIMP-1 on the cone mosaic in the retina of the rat model of retinitis pigmentosa. Invest Ophthalmol Vis Sci 2014; 56:352-64. [PMID: 25515575 DOI: 10.1167/iovs.14-15398] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
PURPOSE The array of photoreceptors found in normal retinas provides uniform and regular sampling of the visual space. In contrast, cones in retinas of the S334ter-line-3 rat model for RP migrate to form a mosaic of rings, leaving large holes with few or no photoreceptors. Similar mosaics appear in human patients with other forms of retinal dystrophy. In the current study, we aimed to investigate the effect of tissue inhibitor of metalloproteinase-1 (TIMP-1) on the mosaic of cones in S334ter-line-3 rat retinas. We focused on TIMP-1 because it is one of the regulators of the extracellular matrix important for cellular migration. METHODS Immunohistochemistry was performed to reveal M-opsin cone cells (M-cone) and the results were quantified to test statistically whether or not TIMP-1 restores the mosaics to normal. In particular, the tests focused on the Voronoi and nearest-neighbor distance analyses. RESULTS Our tests indicated that TIMP-1 led to significant disruption of the M-opsin cone rings in S334ter-line-3 rat retinas and resulted in almost complete homogeneous mosaics. In addition, TIMP-1 induced the M-cone spatial distribution to become closer to random with decreased regularity in S334ter-line-3 rat retinas. CONCLUSIONS These findings confirm that TIMP-1 induced M-cone mosaics in S334ter-line-3 to gain homogeneity without reaching the degree of regularity seen in normal retinal mosaics. Even if TIMP-1 fails to promote regularity, the effects of this drug on homogeneity appear to be so dramatic that TIMP-1 may be a potential therapeutic agent. TIMP-1 improves sampling of the visual field simply by causing homogeneity.
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Affiliation(s)
- Yerina Ji
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States Center for Vision Science and Technology, University of Southern California, Los Angeles, California, United States
| | - Wan-Qing Yu
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States Center for Vision Science and Technology, University of Southern California, Los Angeles, California, United States
| | - Yun Sung Eom
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, United States
| | - Farouk Bruce
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, United States
| | - Cheryl Mae Craft
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States Mary D. Allen Laboratory for Vision Research, Keck School of Medicine of the University of Southern California, USC Eye Institute, Los Angeles, California, United States
| | - Norberto M Grzywacz
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States Department of Electrical Engineering, University of Southern California, Los Angeles, California, United States
| | - Eun-Jin Lee
- Center for Vision Science and Technology, University of Southern California, Los Angeles, California, United States
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Inayat S, Rountree CM, Troy JB, Saggere L. Chemical stimulation of rat retinal neurons: feasibility of an epiretinal neurotransmitter-based prosthesis. J Neural Eng 2014; 12:016010. [PMID: 25504758 DOI: 10.1088/1741-2560/12/1/016010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
OBJECTIVE No cure currently exists for photoreceptor degenerative diseases, which cause partial or total blindness in millions of people worldwide. Electrical retinal prostheses have been developed by several groups with the goal of restoring vision lost to these diseases, but electrical stimulation has limitations. It excites both somas and axons, activating retinal pathways nonphysiologically, and limits spatial resolution because of current spread. Chemical stimulation of retinal ganglion cells (RGCs) using the neurotransmitter glutamate has been suggested as an alternative to electrical stimulation with some significant advantages. However, sufficient scientific data to support developing a chemical-based retinal prosthesis is lacking. The goal of this study was to investigate the feasibility of a neurotransmitter-based retinal prosthesis and determine therapeutic stimulation parameters. APPROACH We injected controlled amounts of glutamate into rat retinas from the epiretinal side ex vivo via micropipettes using a pressure injection system and recorded RGC responses with a multielectrode array. Responsive units were identified using a spike rate threshold of 3 Hz. MAIN RESULTS We recorded both somal and axonal units and demonstrated successful glutamatergic stimulation across different RGC subtypes. Analyses show that exogenous glutamate acts on RGC synapses similar to endogenous glutamate and, unlike electrical prostheses, stimulates only RGC somata. The spatial spread of glutamate stimulation was ≈ 290 μm from the injection site, comparable to current electrical prostheses. Further, the glutamate injections produced spatially differential responses in OFF, ON, and ON-OFF RGC subtypes, suggesting that differential stimulation of the OFF and ON systems may be possible. A temporal resolution of 3.2 Hz was obtained, which is a rate suitable for spatial vision. SIGNIFICANCE We provide strong support for the feasibility of an epiretinal neurotransmitter-based retinal prosthesis. Our findings suggest that chemical stimulation of RGCs is a viable alternative to electrical stimulation and could offer distinct advantages such as the selective stimulation of RGC somata.
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Affiliation(s)
- Samsoon Inayat
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, Illinois, USA. Department of Neurobiology, Northwestern University, Evanston, Illinois, USA
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