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Li S, Ma H, Yang F, Ding X. cGMP Signaling in Photoreceptor Degeneration. Int J Mol Sci 2023; 24:11200. [PMID: 37446378 PMCID: PMC10342299 DOI: 10.3390/ijms241311200] [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: 05/23/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 07/15/2023] Open
Abstract
Photoreceptors in the retina are highly specialized neurons with photosensitive molecules in the outer segment that transform light into chemical and electrical signals, and these signals are ultimately relayed to the visual cortex in the brain to form vision. Photoreceptors are composed of rods and cones. Rods are responsible for dim light vision, whereas cones are responsible for bright light, color vision, and visual acuity. Photoreceptors undergo progressive degeneration over time in many hereditary and age-related retinal diseases. Despite the remarkable heterogeneity of disease-causing genes, environmental factors, and pathogenesis, the progressive death of rod and cone photoreceptors ultimately leads to loss of vision/blindness. There are currently no treatments available for retinal degeneration. Cyclic guanosine 3', 5'-monophosphate (cGMP) plays a pivotal role in phototransduction. cGMP governs the cyclic nucleotide-gated (CNG) channels on the plasma membrane of the photoreceptor outer segments, thereby regulating membrane potential and signal transmission. By gating the CNG channels, cGMP regulates cellular Ca2+ homeostasis and signal transduction. As a second messenger, cGMP activates the cGMP-dependent protein kinase G (PKG), which regulates numerous targets/cellular events. The dysregulation of cGMP signaling is observed in varieties of photoreceptor/retinal degenerative diseases. Abnormally elevated cGMP signaling interferes with various cellular events, which ultimately leads to photoreceptor degeneration. In line with this, strategies to reduce cellular cGMP signaling result in photoreceptor protection in mouse models of retinal degeneration. The potential mechanisms underlying cGMP signaling-induced photoreceptor degeneration involve the activation of PKG and impaired Ca2+ homeostasis/Ca2+ overload, resulting from overactivation of the CNG channels, as well as the subsequent activation of the downstream cellular stress/death pathways. Thus, targeting the cellular cGMP/PKG signaling and the Ca2+-regulating pathways represents a significant strategy for photoreceptor protection in retinal degenerative diseases.
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Affiliation(s)
| | | | | | - Xiqin Ding
- Department of Cell Biology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.L.); (H.M.); (F.Y.)
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Phenotype Characterization of a Mice Genetic Model of Absolute Blindness. Int J Mol Sci 2022; 23:ijms23158152. [PMID: 35897728 PMCID: PMC9331777 DOI: 10.3390/ijms23158152] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/19/2022] [Accepted: 07/22/2022] [Indexed: 11/17/2022] Open
Abstract
Recent technological development requires new approaches to address the problem of blindness. Such approaches need to be able to ensure that no cells with photosensitive capability remain in the retina. The presented model, Opn4−/− × Pde6brd10/rd10 (O×Rd) double mutant murine, is a combination of a mutation in the Pde6b gene (photoreceptor degeneration) together with a deletion of the Opn4 gene (responsible for the expression of melanopsin in the intrinsically photosensitive retinal ganglion cells). This model has been characterized and compared with those of WT mice and murine animal models displaying both mutations separately. A total loss of pupillary reflex was observed. Likewise, behavioral tests demonstrated loss of rejection to illuminated spaces and a complete decrease in visual acuity (optomotor test). Functional recordings showed an absolute disappearance of various wave components of the full-field and pattern electroretinogram (fERG, pERG). Likewise, visual evoked potential (VEP) could not be recorded. Immunohistochemical staining showed marked degeneration of the outer retinal layers and the absence of melanopsin staining. The combination of both mutations has generated an animal model that does not show any photosensitive element in its retina. This model is a potential tool for the study of new ophthalmological approaches such as optosensitive agents.
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Brown C, Agosta P, McKee C, Walker K, Mazzella M, Alamri A, Svinarich D, Chaudhry GR. Human primitive mesenchymal stem cell-derived retinal progenitor cells improved neuroprotection, neurogenesis, and vision in rd12 mouse model of retinitis pigmentosa. Stem Cell Res Ther 2022; 13:148. [PMID: 35395806 PMCID: PMC8994263 DOI: 10.1186/s13287-022-02828-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 03/20/2022] [Indexed: 01/05/2023] Open
Abstract
Background Currently, there is no treatment for retinal degenerative diseases (RDD) such as retinitis pigmentosa (RP). Stem cell-based therapies could provide promising opportunities to repair the damaged retina and restore vision. Thus far, primarily adult mesenchymal stem cells (MSCs) have been investigated in preclinical and clinical studies, and the results have not been convincing. We applied a new approach in which primitive (p) MSC-derived retinal progenitor cells (RPCs) were examined to treat retinal degeneration in an rd12 mouse model of RP. Methods Well-characterized pMSCs and RPCs labeled with PKH26 were intravitreally injected into rd12 mice. The vision and retinal function of transplanted animals were analyzed using electroretinography. Animals were killed 4 and 8 weeks after cell transplantation for histological, immunological, molecular, and transcriptomic analyses of the retina. Results Transplanted RPCs significantly improved vision and retinal thickness as well as function in rd12 mice. pMSCs and RPCs homed to distinct retinal layers. pMSCs homed to the retinal pigment epithelium, and RPCs migrated to the neural layers of the retina, where they improved the thickness of the respective layers and expressed cell-specific markers. RPCs induced anti-inflammatory and neuroprotective responses as well as upregulated the expression of genes involved in neurogenesis. The transcriptomic analysis showed that RPCs promoted neurogenesis and functional recovery of the retina through inhibition of BMP and activation of JAK/STAT and MAPK signaling pathways. Conclusions Our study demonstrated that RPCs countered inflammation, provided retinal protection, and promoted neurogenesis resulting in improved retinal structure and physiological function in rd12 mice. Supplementary Information The online version contains supplementary material available at 10.1186/s13287-022-02828-w.
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Affiliation(s)
- Christina Brown
- Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA.,OU-WB Institute for Stem Cell and Regenerative Medicine, Rochester, MI, 48309, USA
| | - Patrina Agosta
- Ascension Providence Hospital, Southfield, MI, 48075, USA
| | - Christina McKee
- Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA.,OU-WB Institute for Stem Cell and Regenerative Medicine, Rochester, MI, 48309, USA
| | - Keegan Walker
- Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA.,OU-WB Institute for Stem Cell and Regenerative Medicine, Rochester, MI, 48309, USA
| | - Matteo Mazzella
- Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA.,OU-WB Institute for Stem Cell and Regenerative Medicine, Rochester, MI, 48309, USA
| | - Ali Alamri
- Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA.,OU-WB Institute for Stem Cell and Regenerative Medicine, Rochester, MI, 48309, USA
| | | | - G Rasul Chaudhry
- Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA. .,OU-WB Institute for Stem Cell and Regenerative Medicine, Rochester, MI, 48309, USA.
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4
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Weh E, Scott K, Wubben TJ, Besirli CG. Dark-reared rd10 mice experience rapid photoreceptor degeneration with short exposure to room-light during in vivo retinal imaging. Exp Eye Res 2022; 215:108913. [PMID: 34965404 PMCID: PMC8923962 DOI: 10.1016/j.exer.2021.108913] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 12/21/2021] [Accepted: 12/22/2021] [Indexed: 02/03/2023]
Abstract
Inherited retinal diseases (IRDs) are a collection of rare genetic conditions, which can lead to complete blindness. A large number of causative genes have been identified for IRDs and while some success has been achieved with gene therapies, they are limited in scope to each individual gene and/or the specific mutation harbored by each patient with an IRD. Multiple studies are underway to elucidate common underlying mechanisms contributing to photoreceptor (PR) loss and to design gene-agnostic, pan-disease therapeutics. The rd10 mouse, which recapitulates slow degeneration of PRs, is an in vivo IRD model used commonly by vision researchers. Light deprivation by rearing animals in complete darkness significantly delays PR death in rd10 mice, subsequently increasing the time window for in vivo studies investigating neuroprotective strategies. Longitudinal in vivo retinal imaging following the same rd10 mice over time is a potential solution for reducing the number of animals required to complete a study. We describe a previously unreported phenotype in the dark-reared rd10 model that is characterized by dramatic PR degeneration following brief exposure to low-intensity light. This exquisite light sensitivity precludes the use of longitudinal studies employing in vivo imaging or other functional assessment requiring room light in rd10 mice and highlights the importance of closely following animal models of IRD to determine any deviations from the expected degeneration curve during routine experimentation.
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Affiliation(s)
| | | | | | - Cagri G. Besirli
- Corresponding Author, please direct all correspondence to: Cagri Besirli, 1000 Wall St., Ann Arbor, MI 48105, 734-232-8404,
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Sher I, Moverman D, Ketter-Katz H, Moisseiev E, Rotenstreich Y. In vivo retinal imaging in translational regenerative research. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:1096. [PMID: 33145315 PMCID: PMC7575995 DOI: 10.21037/atm-20-4355] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Regenerative translational studies must include a longitudinal assessment of the changes in retinal structure and function that occur as part of the natural history of the disease and those that result from the studied intervention. Traditionally, retinal structural changes have been evaluated by histological analysis which necessitates sacrificing the animals. In this review, we describe key imaging approaches such as fundus imaging, optical coherence tomography (OCT), OCT-angiography, adaptive optics (AO), and confocal scanning laser ophthalmoscopy (cSLO) that enable noninvasive, non-contact, and fast in vivo imaging of the posterior segment. These imaging technologies substantially reduce the number of animals needed and enable progression analysis and longitudinal follow-up in individual animals for accurate assessment of disease natural history, effects of interventions and acute changes. We also describe the benefits and limitations of each technology, as well as outline possible future directions that can be taken in translational retinal imaging studies.
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Affiliation(s)
- Ifat Sher
- Goldschleger Eye Institute, Sheba Medical Center, Tel-Hashomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Daniel Moverman
- Goldschleger Eye Institute, Sheba Medical Center, Tel-Hashomer, Israel
| | - Hadas Ketter-Katz
- Goldschleger Eye Institute, Sheba Medical Center, Tel-Hashomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Elad Moisseiev
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Ophthalmology, Meir Medical Center, Kfar Saba, Israel
| | - Ygal Rotenstreich
- Goldschleger Eye Institute, Sheba Medical Center, Tel-Hashomer, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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Hasegawa T, Ikeda HO, Gotoh N, Iida K, Iwai S, Nakano N, Kakizuka A, Tsujikawa A. Effect of VCP modulators on gene expression profiles of retinal ganglion cells in an acute injury mouse model. Sci Rep 2020; 10:4251. [PMID: 32144342 PMCID: PMC7060332 DOI: 10.1038/s41598-020-61160-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 02/10/2020] [Indexed: 11/09/2022] Open
Abstract
In glaucoma, retinal ganglion cells are damaged, leading to the progressive constriction of the visual field. We have previously shown that the valosin-containing protein (VCP) modulators, Kyoto University Substance (KUS)121 and KUS187, prevent the death of retinal ganglion cells in animal models of glaucoma, including the one generated by N-methyl-D-aspartate (NMDA)-induced neurotoxicity. KUSs appeared to avert endoplasmic reticulum (ER) stress by maintaining ATP levels, resulting in the protection of ganglion cells from cell death. To further elucidate the protective mechanisms of KUSs, we examined gene expression profiles in affected ganglion cells. We first injected KUS-treated mice with NMDA and then isolated the affected retinal ganglion cells using fluorescence-activated cell sorting. Gene expression in the cells was quantified using a next-generation sequencer. Resultantly, we found that KUS121 upregulated several genes involved in energy metabolism. In addition, we observed the upregulation of Zfp667, which has been reported to suppress apoptosis-related genes and prevent cell death. These results further support the suitability of KUS121 as a therapeutic drug in protecting retinal ganglion cells in ophthalmic disorders, such as glaucoma.
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Affiliation(s)
- Tomoko Hasegawa
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan
| | - Hanako Ohashi Ikeda
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan.
| | - Norimoto Gotoh
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan
| | - Kei Iida
- Medical Research Support Center, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan
| | - Sachiko Iwai
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan
| | - Noriko Nakano
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan
| | - Akira Kakizuka
- Laboratory of Functional Biology, Kyoto University Graduate School of Biostudies & Solution Oriented Research for Science and Technology, Kyoto, 606-8501, Japan
| | - Akitaka Tsujikawa
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan
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Cuenca N, Ortuño-Lizarán I, Sánchez-Sáez X, Kutsyr O, Albertos-Arranz H, Fernández-Sánchez L, Martínez-Gil N, Noailles A, López-Garrido JA, López-Gálvez M, Lax P, Maneu V, Pinilla I. Interpretation of OCT and OCTA images from a histological approach: Clinical and experimental implications. Prog Retin Eye Res 2020; 77:100828. [PMID: 31911236 DOI: 10.1016/j.preteyeres.2019.100828] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 12/16/2019] [Accepted: 12/30/2019] [Indexed: 12/17/2022]
Abstract
Optical coherence tomography (OCT) and OCT angiography (OCTA) have been a technological breakthrough in the diagnosis, treatment, and follow-up of many retinal diseases, thanks to its resolution and its ability to inform of the retinal state in seconds, which gives relevant information about retinal degeneration. In this review, we present an immunohistochemical description of the human and mice retina and we correlate it with the OCT bands in health and pathological conditions. Here, we propose an interpretation of the four outer hyperreflective OCT bands with a correspondence to retinal histology: the first and innermost band as the external limiting membrane (ELM), the second band as the cone ellipsoid zone (EZ), the third band as the outer segment tips phagocytosed by the pigment epithelium (PhaZ), and the fourth band as the mitochondria in the basal portion of the RPE (RPEmitZ). The integrity of these bands would reflect the health of photoreceptors and retinal pigment epithelium. Moreover, we describe how the vascular plexuses vary in different regions of the healthy human and mice retina, using OCTA and immunohistochemistry. In humans, four, three, two or one plexuses can be observed depending on the distance from the fovea. Also, specific structures such as vascular loops in the intermediate capillary plexus, or spider-like structures of interconnected capillaries in the deep capillary plexus are found. In mice, three vascular plexuses occupy the whole retina, except in the most peripheral retina where only two plexuses are found. These morphological issues should be considered when assessing a pathology, as some retinal diseases are associated with structural changes in blood vessels. Therefore, the analysis of OCT bands and OCTA vascular plexuses may be complementary for the diagnosis and prognosis of retinal degenerative processes, useful to assess therapeutic approaches, and it is usually correlated to visual acuity.
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Affiliation(s)
- Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of Alicante, Spain; Institute Ramón Margalef, University of Alicante, Alicante, Spain.
| | | | - Xavier Sánchez-Sáez
- Department of Physiology, Genetics and Microbiology, University of Alicante, Spain
| | - Oksana Kutsyr
- Department of Physiology, Genetics and Microbiology, University of Alicante, Spain
| | | | | | - Natalia Martínez-Gil
- Department of Physiology, Genetics and Microbiology, University of Alicante, Spain
| | - Agustina Noailles
- Department of Physiology, Genetics and Microbiology, University of Alicante, Spain
| | | | | | - Pedro Lax
- Department of Physiology, Genetics and Microbiology, University of Alicante, Spain
| | - Victoria Maneu
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Spain
| | - Isabel Pinilla
- Department of Ophthalmology, Lozano Blesa, University Hospital, Zaragoza, Spain
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8
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Optical Coherence Tomography of Animal Models of Retinitis Pigmentosa: From Animal Studies to Clinical Applications. BIOMED RESEARCH INTERNATIONAL 2019; 2019:8276140. [PMID: 31781647 PMCID: PMC6875330 DOI: 10.1155/2019/8276140] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 09/18/2019] [Indexed: 11/17/2022]
Abstract
Purpose The aim of this study was to understand the relationship between the findings of spectral-domain optical coherence tomography (SD-OCT) of previously reported animal models of retinitis pigmentosa (RP) associated with known genetic mutations and their background structural and functional changes. Methods We reviewed previous publications reporting the SD-OCT findings of animal models of RP and summarized the characteristic findings of SD-OCT in nine different animal models (RCS -/- , RHO P23H, RHO S334ter, RHO -/- , Rpe65 -/- , rp12, Pde6β -/- (rd1 and rd10), and Arr1 -/- ) of human RP. Results Despite the various abnormal structural changes found in these different animal models, progressive thinning of the outer nuclear layer (ONL) and hyperreflective change in the inner and outer segment (IS-OS) layers of the photoreceptors were commonly observed on SD-OCT. In the rapidly progressive severe photoreceptor degeneration seen in rd10 and Arr1 -/- mice, the ONL appeared hyperreflective. Electroretinography revealed various degrees of disease severity in these animal models. Discussion and Conclusion: SD-OCT is sensitive enough to detect even mild changes in the photoreceptor OS. Conversely, SD-OCT cannot qualitatively differentiate the pathologic and functional differences in the photoreceptors associated with different genetic abnormalities, with the exception of the rapid progression of severe forms of photoreceptor degeneration. These findings can be of value to understand better the clinical findings and the heterogeneous degenerative processes in patients with RP.
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Hasegawa T, Ikeda HO. Adenosine triphosphate maintenance by branched chain amino acids as a novel neuroprotective strategy for retinal neurodegenerative diseases. Neural Regen Res 2019; 14:82-84. [PMID: 30531080 PMCID: PMC6263008 DOI: 10.4103/1673-5374.244788] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Tomoko Hasegawa
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hanako Ohashi Ikeda
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine; Department of Experimental Therapeutics, Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan
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10
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Kim TH, Son T, Lu Y, Alam M, Yao X. Comparative Optical Coherence Tomography Angiography of Wild-Type and rd10 Mouse Retinas. Transl Vis Sci Technol 2018; 7:42. [PMID: 30619662 PMCID: PMC6314228 DOI: 10.1167/tvst.7.6.42] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 11/02/2018] [Indexed: 12/11/2022] Open
Abstract
Purpose To conduct longitudinal optical coherence tomography angiography (OCTA) to characterize dynamic changes of trilaminar vascular plexuses in wild-type (WT) and retinal degeneration 10 (rd10) mouse retinas. Methods Longitudinal in vivo OCT/OCTA measurements of WT and rd10 mouse retinas were conducted at postnatal day 14 (P14), P17, P21, P24, and P28. OCT images were used to quantify retinal thickness changes, while OCTA images were used to investigate vascular dynamics within the trilaminar vascular plexuses, that is, superficial vascular plexus (SVP), intermediate capillary plexus (ICP), and deep capillary plexus (DCP). Blood vessel densities of all three plexus layers were quantitatively evaluated separately. The caliber of first-order blood vessel branches in the SVP layer was also measured. Results Vascular densities in all three plexuses continuously decreased with aging in both WT and rd10. However, abnormal density reduction in rd10 occurred at P17 in both ICP (P < 0.001) and DCP (P < 0.001). While the ICP of rd10 showed density recovery at P24, the DCP of rd10 showed significantly low density. Remarkable vascular narrowing in rd10 was also observed in the SVP, especially at P28. Conclusions The most severe vascular impairment happened in the DCP, while the ICP showed the transient recovery of vascular density after the onset of retinal degeneration. The SVP was most resistant to the retinal degeneration, but the first-order blood vessel branches within the SVP showed progressive narrowing. Translational Relevance Better understanding of the vascular changes correlated with retinal development, and retinal degeneration can provide insights in advanced development of treatment protocols of retinal degenerative diseases.
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Affiliation(s)
- Tae-Hoon Kim
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Taeyoon Son
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Yiming Lu
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Minhaj Alam
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA.,Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
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11
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Wang T, Reingruber J, Woodruff ML, Majumder A, Camarena A, Artemyev NO, Fain GL, Chen J. The PDE6 mutation in the rd10 retinal degeneration mouse model causes protein mislocalization and instability and promotes cell death through increased ion influx. J Biol Chem 2018; 293:15332-15346. [PMID: 30126843 DOI: 10.1074/jbc.ra118.004459] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/13/2018] [Indexed: 12/20/2022] Open
Abstract
The retinal degeneration model rd10 contains a missense mutation of the catalytic PDE6 β subunit, which hydrolyzes cGMP in response to light. This model produces cell death more slowly than others caused by PDE6 loss of function, making it of particular interest for studying potential therapeutics. We used morphology, biochemistry, and single-cell physiology to examine the mechanism of rd10 degeneration. Our results show that the mutation produces no alteration of Pde6b RNA but does dramatically decrease maximal and basal PDE6 activity, apparently caused by a decrease in protein stability and transport. The enzymatic properties of the remaining mutant PDE6 appear to be nearly normal. We demonstrate that an increase in free cGMP, which would result from decreased PDE6 activity and serve to increase opening of the cGMP-gated channels and calcium influx, is an underlying cause of cell death: degeneration of rd10/Cngb1 -/- double mutants is slower than the parent rd10 line. Paradoxically, degeneration in rd10/Cngb1 -/- is also slower than in Cngb1 -/- This rescue is correlated with a lowering of cGMP content in Cngb1 -/- retinas and suggests that it may be caused by mislocalization of active PDE6. Single-cell recordings from rd10 rods show that the rates of rise and decay of the response are significantly slower; simulations indicate that these changes are primarily the result of the decrease in PDE6 concentration and rod collecting area. Together, these results provide insights into the complex mechanisms that underlie rd10-mediated retinal degeneration and a cautionary note for analysis of therapeutic interventions.
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Affiliation(s)
- Tian Wang
- From the Zilkha Neurogenetic Institute and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California 90089-2821
| | - Jürgen Reingruber
- the Institut de Biologie, Group of Computational Biology and Applied Mathematics, École Normale Supérieure, 75005 Paris, France
| | - Michael L Woodruff
- the Department of Integrative Biology and Physiology, UCLA, Los Angeles, California 90095-1606
| | - Anurima Majumder
- the Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, and
| | - Andres Camarena
- From the Zilkha Neurogenetic Institute and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California 90089-2821
| | - Nikolai O Artemyev
- the Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, and
| | - Gordon L Fain
- the Department of Integrative Biology and Physiology, UCLA, Los Angeles, California 90095-1606.,the Department of Ophthalmology, Jules Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, California 90095-7000
| | - Jeannie Chen
- From the Zilkha Neurogenetic Institute and Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California 90089-2821,
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12
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Branched chain amino acids attenuate major pathologies in mouse models of retinal degeneration and glaucoma. Heliyon 2018; 4:e00544. [PMID: 29560458 PMCID: PMC5857634 DOI: 10.1016/j.heliyon.2018.e00544] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 01/11/2018] [Accepted: 02/09/2018] [Indexed: 12/22/2022] Open
Abstract
Retinal neuronal cell death underlies many incurable eye diseases such as retinitis pigmentosa (RP) and glaucoma, and causes adult blindness. We have shown that maintenance of ATP levels via inhibiting ATP consumption is a promising strategy for preventing neuronal cell death. Here, we show that branched chain amino acids (BCAAs) are able to increase ATP production by enhancing glycolysis. In cell culture, supplementation of the culture media with BCAAs, but not glucose alone, enhanced cellular ATP levels, which was canceled by a glycolysis inhibitor. Administration of BCAAs to RP mouse models, rd10 and rd12, significantly attenuated photoreceptor cell death morphologically and functionally, even when administration was started at later stages. Administration of BCAAs in a glaucoma mouse model also showed significant attenuation of retinal ganglion cell death. These results suggest that administration of BCAAs could contribute to a comprehensive therapeutic strategy for retinal neurodegenerative diseases such as RP and glaucoma.
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Wang J, Saul A, Cui X, Roon P, Smith SB. Absence of Sigma 1 Receptor Accelerates Photoreceptor Cell Death in a Murine Model of Retinitis Pigmentosa. Invest Ophthalmol Vis Sci 2017; 58:4545-4558. [PMID: 28877319 PMCID: PMC5586962 DOI: 10.1167/iovs.17-21947] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 07/31/2017] [Indexed: 02/06/2023] Open
Abstract
Purpose Sigma 1 Receptor (Sig1R) is a novel therapeutic target in neurodegenerative diseases, including retinal disease. Sig1R-/- mice have late-onset retinal degeneration with ganglion cell loss that worsens under stress. Whether Sig1R plays a role in maintaining other retinal neurons is unknown, but was investigated here using rd10 mice, a model of severe photoreceptor degeneration. Methods Wild-type, rd10, and rd10/Sig1R-/- mice were subjected to ERG and spectral-domain optical coherence tomography (SD-OCT) to assess visual function/structure in situ. Retinas imaged microscopically were subjected to morphometric analysis, immunodetection of cones, and analysis of gliosis. Oxidative and endoplasmic reticulum (ER) stress was evaluated at mRNA/protein levels. Results Photopic ERG responses were reduced significantly in rd10/Sig1R-/- versus rd10 mice at P28 (31 ± 6 vs. 56 ± 7 μV), indicating accelerated cone loss when Sig1R was absent. At P28, SD-OCT revealed reduced retinal thickness in rd10/Sig1R-/- mice (60% of WT) versus rd10 (80% of WT). Morphometric analysis disclosed profound photoreceptor nuclei loss in rd10/Sig1R-/- versus rd10 mice. rd10/Sig1R-/- mice had 35% and 60% fewer photoreceptors, respectively, at P28 and P35, than rd10. Peanut agglutinin cone labeling decreased significantly; gliosis increased significantly in rd10/Sig1R-/- versus rd10 mice. At P21, NRF2 levels increased in rd10/Sig1R-/- mice versus rd10 and downstream antioxidants increased indicating oxidative stress. At P28, ER stress genes/proteins, especially XBP1, a potent transcriptional activator of the unfolded protein response and CHOP, a proapoptotic transcription factor, increased significantly in rd10/Sig1R-/- mice versus rd10. Conclusions Photoreceptor cell degeneration accelerates and cone function diminishes much earlier in rd10/Sig1R-/- than rd10 mice emphasizing the importance of Sig1R as a modulator of retinal cell survival.
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Affiliation(s)
- Jing Wang
- Department of Cellular Biology and Anatomy, The Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- The James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia, United States
| | - Alan Saul
- The James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia, United States
- Department of Ophthalmology, Augusta University, Augusta, Georgia, United States
| | - Xuezhi Cui
- Department of Cellular Biology and Anatomy, The Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- The James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia, United States
| | - Penny Roon
- Department of Cellular Biology and Anatomy, The Medical College of Georgia at Augusta University, Augusta, Georgia, United States
| | - Sylvia B. Smith
- Department of Cellular Biology and Anatomy, The Medical College of Georgia at Augusta University, Augusta, Georgia, United States
- The James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia, United States
- Department of Ophthalmology, Augusta University, Augusta, Georgia, United States
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Jalligampala A, Sekhar S, Zrenner E, Rathbun DL. Optimal voltage stimulation parameters for network-mediated responses in wild type and rd10 mouse retinal ganglion cells. J Neural Eng 2017; 14:026004. [PMID: 28155848 DOI: 10.1088/1741-2552/14/2/026004] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
To further improve the quality of visual percepts elicited by microelectronic retinal prosthetics, substantial efforts have been made to understand how retinal neurons respond to electrical stimulation. It is generally assumed that a sufficiently strong stimulus will recruit most retinal neurons. However, recent evidence has shown that the responses of some retinal neurons decrease with excessively strong stimuli (a non-monotonic response function). Therefore, it is necessary to identify stimuli that can be used to activate the majority of retinal neurons even when such non-monotonic cells are part of the neuronal population. Taking these non-monotonic responses into consideration, we establish the optimal voltage stimulation parameters (amplitude, duration, and polarity) for epiretinal stimulation of network-mediated (indirect) ganglion cell responses. We recorded responses from 3958 mouse retinal ganglion cells (RGCs) in both healthy (wild type, WT) and a degenerating (rd10) mouse model of retinitis pigmentosa-using flat-mounted retina on a microelectrode array. Rectangular monophasic voltage-controlled pulses were presented with varying voltage, duration, and polarity. We found that in 4-5 weeks old rd10 mice the RGC thresholds were comparable to those of WT. There was a marked response variability among mouse RGCs. To account for this variability, we interpolated the percentage of RGCs activated at each point in the voltage-polarity-duration stimulus space, thus identifying the optimal voltage-controlled pulse (-2.4 V, 0.88 ms). The identified optimal voltage pulse can activate at least 65% of potentially responsive RGCs in both mouse strains. Furthermore, this pulse is well within the range of stimuli demonstrated to be safe and effective for retinal implant patients. Such optimized stimuli and the underlying method used to identify them support a high yield of responsive RGCs and will serve as an effective guideline for future in vitro investigations of retinal electrostimulation by establishing standard stimuli for each unique experimental condition.
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Affiliation(s)
- Archana Jalligampala
- Institute for Ophthalmic Research, Eberhard Karls University, D-72076 Tübingen, Germany. Werner Reichardt Centre for Integrative Neuroscience (CIN), D-72076 Tübingen, Germany. Graduate Training Center of Neuroscience/International Max Planck Research School, D-72074 Tübingen, Germany
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15
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Optical Coherence Tomography of Retinal Degeneration in Royal College of Surgeons Rats and Its Correlation with Morphology and Electroretinography. PLoS One 2016; 11:e0162835. [PMID: 27644042 PMCID: PMC5028068 DOI: 10.1371/journal.pone.0162835] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 08/29/2016] [Indexed: 11/19/2022] Open
Abstract
Purpose To evaluate the correlation between optical coherence tomography (OCT) and the histological, ultrastructural and electroretinography (ERG) findings of retinal degeneration in Royal College of Surgeons (RCS-/-) rats. Materials and Methods Using OCT, we qualitatively and quantitatively observed the continual retinal degeneration in RCS-/- rats, from postnatal (PN) day 17 until PN day 111. These findings were compared with the corresponding histological, electron microscopic, and ERG findings. We also compared them to OCT findings in wild type RCS+/+ rats, which were used as controls. Results After PN day 17, the hyperreflective band at the apical side of the photoreceptor layer became blurred. The inner segment (IS) ellipsoid zone then became obscured, and the photoreceptor IS and outer segment (OS) layers became diffusely hyperreflective after PN day 21. These changes correlated with histological and electron microscopic findings showing extracellular lamellar material that accumulated in the photoreceptor OS layer. After PN day 26, the outer nuclear layer became significantly thinner (P < 0.01) and hyperreflective compared with that in the controls; conversely, the photoreceptor IS and OS layers, as well as the inner retinal layers, became significantly thicker (P < 0.001 and P = 0.05, respectively). The apical hyperreflective band, as well as the IS ellipsoid zone, gradually disappeared between PN day 20 and PN day 30; concurrently, the ERG a- and b-wave amplitudes deteriorated. In contrast, the thicknesses of the combined retinal pigment epithelium and choroid did not differ significantly between RCS-/- and RCS+/+ rats. Conclusion Our results suggest that OCT demonstrates histologically validated photoreceptor degeneration in RCS rats, and that OCT findings partly correlate with ERG findings. We propose that OCT is a less invasive and useful method for evaluating photoreceptor degeneration in animal models of retinitis pigmentosa.
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Hasegawa T, Muraoka Y, Ikeda HO, Tsuruyama T, Kondo M, Terasaki H, Kakizuka A, Yoshimura N. Neuoroprotective efficacies by KUS121, a VCP modulator, on animal models of retinal degeneration. Sci Rep 2016; 6:31184. [PMID: 27503804 PMCID: PMC4977562 DOI: 10.1038/srep31184] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/14/2016] [Indexed: 12/17/2022] Open
Abstract
Retinitis pigmentosa (RP) is one of the leading causes of adult blindness and has no established therapy. We have shown that valosin-containing protein (VCP) modulators, Kyoto University Substances (KUSs), ameliorated abnormally low ATP levels by inhibiting the ATPase of VCP, thereby protected several types of cells, including retinal neurons, from cell death-inducing insults. In this study, we found that KUS121, one of the VCP modulators, effectively protects photoreceptors both morphologically and functionally, in two animal models of retinal degeneration, rd12 mice and RP rabbits with a rhodopsin (Pro347Leu) mutation. In rd12 mice, KUS121 suppressed the loss of photoreceptors, not only rods but also cones, as well as the visual function deterioration. Significant protective effects existed even when the medication was started in later stages of the disease. In RP rabbits, KUS121 suppressed thinning of the outer nuclear layer and maintained visual function. In the retinas treated with KUS121, suppression of endoplasmic reticulum stress, activation of mammalian target of rapamycin and suppression of disease-associated apoptosis were evident. The ability of KUS121 to protect photoreceptors, especially cones, even in later stages of the disease may contribute to the preservation of central vision in RP patients, which is important for quality of vision.
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Affiliation(s)
- Tomoko Hasegawa
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan
| | - Yuki Muraoka
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan
| | - Hanako Ohashi Ikeda
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan.,Department of Experimental Therapeutics, Institute for Advancement of Clinical and Translational Science, Kyoto university Hospital, Kyoto, 606-8501, Japan
| | - Tatsuaki Tsuruyama
- Center for Anatomical Studies, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan
| | - Mineo Kondo
- Department of Ophthalmology, Mie University Graduate School of Medicine, Tsu, 514-8607, Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, 464-8601, Japan
| | - Akira Kakizuka
- Laboratory of Functional Biology, Kyoto University Graduate School of Biostudies &Solution Oriented Research for Science and Technology, Kyoto, 606-8501, Japan
| | - Nagahisa Yoshimura
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan
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