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Akiba R, Lind Boniec S, Knecht S, Uyama H, Tu HY, Baba T, Takahashi M, Mandai M, Wong RO. Cellular and circuit remodeling of the primate foveal midget pathway after acute photoreceptor loss. Proc Natl Acad Sci U S A 2024; 121:e2413104121. [PMID: 39231211 DOI: 10.1073/pnas.2413104121] [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: 06/30/2024] [Accepted: 08/01/2024] [Indexed: 09/06/2024] Open
Abstract
The retinal fovea in human and nonhuman primates is essential for high acuity and color vision. Within the fovea lies specialized circuitry in which signals from a single cone photoreceptor are largely conveyed to one ON and one OFF type midget bipolar cell (MBC), which in turn connect to a single ON or OFF midget ganglion cell (MGC), respectively. Restoring foveal vision requires not only photoreceptor replacement but also appropriate reconnection with surviving ON and OFF MBCs and MGCs. However, our current understanding of the effects of cone loss on the remaining foveal midget pathway is limited. We thus used serial block-face electron microscopy to determine the degree of plasticity and potential remodeling of this pathway in adult Macaca fascicularis several months after acute photoreceptor loss upon photocoagulation. We reconstructed MBC structure and connectivity within and adjacent to the region of cone loss. We found that MBC dendrites within the scotoma retracted and failed to reach surviving cones to form new connections. However, both surviving cones and ON and OFF MBC dendrites at the scotoma border exhibited remodeling, suggesting that these neurons can demonstrate plasticity and rewiring at maturity. At six months postlesion, disconnected OFF MBCs clearly lost output ribbon synapses with their postsynaptic partners, whereas the majority of ON MBCs maintained their axonal ribbon numbers, suggesting differential timing or extent in ON and OFF midget circuit remodeling after cone loss. Our findings raise rewiring considerations for cell replacement approaches in the restoration of foveal vision.
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Affiliation(s)
- Ryutaro Akiba
- Department of Biological Structure, University of Washington, Seattle, WA 98195
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
- Department of Ophthalmology and Visual Sciences, Chiba University Graduate School of Medicine, Chiba 260-8677, Japan
| | - Shane Lind Boniec
- Department of Biological Structure, University of Washington, Seattle, WA 98195
| | - Sharm Knecht
- Department of Biological Structure, University of Washington, Seattle, WA 98195
| | - Hirofumi Uyama
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Hung-Ya Tu
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Takayuki Baba
- Department of Ophthalmology and Visual Sciences, Chiba University Graduate School of Medicine, Chiba 260-8677, Japan
| | - Masayo Takahashi
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
- Research Center, Kobe City Eye Hospital Research Center, Kobe, Hyogo 650-0047, Japan
| | - Michiko Mandai
- Laboratory for Retinal Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
- Research Center, Kobe City Eye Hospital Research Center, Kobe, Hyogo 650-0047, Japan
| | - Rachel O Wong
- Department of Biological Structure, University of Washington, Seattle, WA 98195
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Velaga SB, Alagorie AR, Emamverdi M, Ashrafkhorasani M, Habibi A, Nittala MG, Sing G, Haines J, Pericak-Vance MA, Stambolian D, Sadda SR. Alterations of the Ganglion Cell Complex in Age-Related Macular Degeneration: An Amish Eye Study Analysis. Am J Ophthalmol 2024; 265:80-87. [PMID: 38677638 DOI: 10.1016/j.ajo.2024.04.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 04/02/2024] [Accepted: 04/22/2024] [Indexed: 04/29/2024]
Abstract
PURPOSE To compare the ganglion cell complex (GCC) thickness in eyes with age-related macular degeneration (AMD) vs healthy controls in an elderly Amish population. DESIGN Prospective cross-sectional study. METHODS This is a post hoc analysis of the family-based prospective study of Amish subjects. Study subjects underwent imaging with the Cirrus HD-OCT (Carl Zeiss Meditec Inc) using a macular cube protocol of 512 × 128 scans (128 horizontal B-scans, each comprising 512 A-scans) over a 6 mm × 6 mm region centered on the fovea. The ganglion cell analysis algorithm calculated the GCC thickness by segmenting the outer boundaries of the retinal nerve fiber layer (RNFL) and inner plexiform layer (IPL) in all B-scans of the volume, with the region between these boundaries representing the combined thickness of the ganglion cell layer (GCL) and the IPL. A number of parameters were used to evaluate the GCC thickness: the average GCC thickness, minimum (lowest GCC thickness at a single meridian crossing the elliptical annulus), and sectoral (within each of 6 sectoral areas: superior, superotemporal, superonasal, inferior, inferonasal, and inferotemporal). The stage of AMD was graded on color fundus photographs in accordance with the Beckman Initiative for Macular Research classification system. RESULTS Of 1339 subjects enrolled in the Amish eye study, a total of 1294 eyes of 1294 subjects had all required imaging studies of sufficient quality and were included in the final analysis. Of these, 798 (62%) were female. Following age adjustment, the average GCC thickness was significantly (P < .001) thinner in AMD subjects (73.71 ± SD; 13.77 µm) compared to normals (77.97 ± 10.42 µm). An independent t test showed that the early AMD (75.03 ± 12.45 µm) and late AMD (61.64 ± 21.18 µm) groups (among which eyes with geographic atrophy [GA] had the lowest thickness, of 58.10 ± 20.27 µm) had a statistically significant lower GCC thickness compared to eyes without AMD. There was no significant differences in average GCC thickness between early AMD and intermediate AMD (76.36 ± 9.25 µm) eyes. CONCLUSIONS The GCC thickness in AMD eyes is reduced compared to normal eyes; however, the relationship is complex, with the greatest reduction in late AMD eyes (particularly eyes with GA) but no difference between early and intermediate AMD eyes.
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Affiliation(s)
- Swetha Bindu Velaga
- From the Doheny Eye Institute (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., G.S., S.R.S.), University of California-Los Angeles, Los Angeles, California, USA; Department of Ophthalmology (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., S.R.S.), David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Ahmed Roshdy Alagorie
- From the Doheny Eye Institute (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., G.S., S.R.S.), University of California-Los Angeles, Los Angeles, California, USA; Department of Ophthalmology (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., S.R.S.), David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Ophthalmology (A.R.A.), Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Mehdi Emamverdi
- From the Doheny Eye Institute (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., G.S., S.R.S.), University of California-Los Angeles, Los Angeles, California, USA; Department of Ophthalmology (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., S.R.S.), David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Maryam Ashrafkhorasani
- From the Doheny Eye Institute (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., G.S., S.R.S.), University of California-Los Angeles, Los Angeles, California, USA; Department of Ophthalmology (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., S.R.S.), David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Abbas Habibi
- From the Doheny Eye Institute (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., G.S., S.R.S.), University of California-Los Angeles, Los Angeles, California, USA; Department of Ophthalmology (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., S.R.S.), David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Muneeswar Gupta Nittala
- From the Doheny Eye Institute (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., G.S., S.R.S.), University of California-Los Angeles, Los Angeles, California, USA; Department of Ophthalmology (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., S.R.S.), David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Gagan Sing
- From the Doheny Eye Institute (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., G.S., S.R.S.), University of California-Los Angeles, Los Angeles, California, USA; Department of Ophthalmology (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., S.R.S.), David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Jonathan Haines
- Department of Population & Quantitative Health Sciences (J.H.), Case Western Reserve University, Cleveland, Ohio, USA; Institute for Computational Biology (J.H.), Case Western Reserve University, Cleveland, Ohio, USA
| | - Margaret A Pericak-Vance
- John P. Hussman Institute for Human Genomics (M.A.P.-V), University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Dwight Stambolian
- Department of Ophthalmology (D.S.), University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Srinivas R Sadda
- From the Doheny Eye Institute (S.B.V., A.R.A., M.E., M.A., A.H., M.G.N., G.S., S.R.S.), University of California-Los Angeles, Los Angeles, California, USA.
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Liao C, Chen S, Chen X, Yi W, Fan Y, Chen Y, Ye T, Chen Y. Inhibition of JNK ameliorates rod photoreceptor degeneration in a mouse model of retinitis pigmentosa. FEBS Lett 2024. [PMID: 39010325 DOI: 10.1002/1873-3468.14978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 06/01/2024] [Accepted: 06/09/2024] [Indexed: 07/17/2024]
Abstract
Retinitis pigmentosa (RP) is an inherited eye disease that causes progressive vision loss. Microglial activation and inflammation play essential roles in photoreceptor degeneration in RP, although the underlying mechanisms remain unclear. Here, we examined the progressive degeneration of photoreceptors in rd1 mice, a mouse model of RP. We investigated the molecular changes in various retinal cells in rd1 mice using single-cell RNA sequencing and found that potentiation of JNK signaling is associated with photoreceptor degeneration in RP. Moreover, inflammation-related molecules, which function downstream of JNK, are elevated in RP. Furthermore, inhibiting JNK alleviates microglial activation and rescues photoreceptor degeneration in rd1 mice. Thus, our findings suggest that targeting JNK is a promising approach for slowing RP progression.
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Affiliation(s)
- Chunyan Liao
- Chinese Academy of Sciences Key Laboratory of Brain Connectome and Manipulation, Shenzhen Key Laboratory of Translational Research for Brain Diseases, Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Shuai Chen
- Chinese Academy of Sciences Key Laboratory of Brain Connectome and Manipulation, Shenzhen Key Laboratory of Translational Research for Brain Diseases, Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
- Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Xuxu Chen
- Chinese Academy of Sciences Key Laboratory of Brain Connectome and Manipulation, Shenzhen Key Laboratory of Translational Research for Brain Diseases, Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
- Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Wanying Yi
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, China
| | - Yingying Fan
- Chinese Academy of Sciences Key Laboratory of Brain Connectome and Manipulation, Shenzhen Key Laboratory of Translational Research for Brain Diseases, Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Yuewen Chen
- Chinese Academy of Sciences Key Laboratory of Brain Connectome and Manipulation, Shenzhen Key Laboratory of Translational Research for Brain Diseases, Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
- Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Beijing, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, China
| | - Tao Ye
- Chinese Academy of Sciences Key Laboratory of Brain Connectome and Manipulation, Shenzhen Key Laboratory of Translational Research for Brain Diseases, Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
- Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Beijing, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, China
| | - Yu Chen
- Chinese Academy of Sciences Key Laboratory of Brain Connectome and Manipulation, Shenzhen Key Laboratory of Translational Research for Brain Diseases, Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
- Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Beijing, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, China
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Zhang L, Liu W, Wang HY, Qiang W, Wang R, Cui ZL, Zhang ZM. The temporal progression of retinal degeneration and early-stage idebenone treatment in the Pde6b rd1/rd1 mouse model of retinal dystrophy. Sci Rep 2024; 14:2019. [PMID: 38263197 PMCID: PMC10805728 DOI: 10.1038/s41598-024-52391-y] [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: 10/24/2023] [Accepted: 01/18/2024] [Indexed: 01/25/2024] Open
Abstract
Photoreceptor cell death, primarily through apoptosis, related to retinal disorders like retinitis pigmentosa (RP), would result in vision loss. The pathological processes and crucial mutant conditions preceding photoreceptor cell demise are not well understood. This study aims to conduct an in-depth examination of early-stage changes in the widely utilized Pde6brd1/rd1 (rd1) mouse model, which has Pde6b gene mutations representing autosomal recessive RP disorder. We investigated the morphology and ultrastructure of retinal cells, including second-order neurons, during the initial phase of disease progression. Our findings revealed that mitochondrial alterations in rod photoreceptors were present as a predeath mutant state as early as postnatal day 3 (P3). The bipolar and horizontal cells from the rd1 mouse retina exhibited significant morphological changes in response to loss of photoreceptor cells, indicating that second-order neurons rely on these cells for their structures. Subsequent oral administration of idebenone, a mitochondria-protective agent, enhanced retinal function and promoted both photoreceptor cell survival and inner retinal second-order synaptogenesis in rd1 mice at P14. Our findings offer a mechanistic framework, suggesting that mitochondrial damage acts as an early driver for photoreceptor cell death in retinal degeneration.
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Affiliation(s)
- Lei Zhang
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, 710004, China
- Xi'an Key Laboratory of Digital Medical Technology of Ophthalmologic Imaging, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, 710004, China
| | - Wei Liu
- Medical Experiment Center, Shaanxi University of Chinese Medicine, Xianyang, Shaanxi Province, China
| | - Hai-Yan Wang
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, 710004, China.
- Xi'an Key Laboratory of Digital Medical Technology of Ophthalmologic Imaging, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, 710004, China.
| | - Wei Qiang
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, 710004, China
- Xi'an Key Laboratory of Digital Medical Technology of Ophthalmologic Imaging, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, 710004, China
| | - Ru Wang
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, 710004, China
- Xi'an Key Laboratory of Digital Medical Technology of Ophthalmologic Imaging, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, 710004, China
| | - Zhi-Li Cui
- Shaanxi Eye Hospital, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, 710004, China
- Xi'an Key Laboratory of Digital Medical Technology of Ophthalmologic Imaging, Xi'an People's Hospital (Xi'an Fourth Hospital), Xi'an, 710004, China
| | - Zuo-Ming Zhang
- Department of Clinical Medicine, Faculty of Aerospace Medicine, Air Force Medical University, Xi'an, 710032, Shaanxi Province, China.
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Zueva MV, Neroeva NV, Zhuravleva AN, Bogolepova AN, Kotelin VV, Fadeev DV, Tsapenko IV. Fractal Phototherapy in Maximizing Retina and Brain Plasticity. ADVANCES IN NEUROBIOLOGY 2024; 36:585-637. [PMID: 38468055 DOI: 10.1007/978-3-031-47606-8_31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
The neuroplasticity potential is reduced with aging and impairs during neurodegenerative diseases and brain and visual system injuries. This limits the brain's capacity to repair the structure and dynamics of its activity after lesions. Maximization of neuroplasticity is necessary to provide the maximal CNS response to therapeutic intervention and adaptive reorganization of neuronal networks in patients with degenerative pathology and traumatic injury to restore the functional activity of the brain and retina.Considering the fractal geometry and dynamics of the healthy brain and the loss of fractality in neurodegenerative pathology, we suggest that the application of self-similar visual signals with a fractal temporal structure in the stimulation therapy can reactivate the adaptive neuroplasticity and enhance the effectiveness of neurorehabilitation. This proposition was tested in the recent studies. Patients with glaucoma had a statistically significant positive effect of fractal photic therapy on light sensitivity and the perimetric MD index, which shows that methods of fractal stimulation can be a novel nonpharmacological approach to neuroprotective therapy and neurorehabilitation. In healthy rabbits, it was demonstrated that a long-term course of photostimulation with fractal signals does not harm the electroretinogram (ERG) and retina structure. Rabbits with modeled retinal atrophy showed better dynamics of the ERG restoration during daily stimulation therapy for a week in comparison with the controls. Positive changes in the retinal function can indirectly suggest the activation of its adaptive plasticity and the high potential of stimulation therapy with fractal visual stimuli in a nonpharmacological neurorehabilitation, which requires further study.
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Affiliation(s)
- Marina V Zueva
- Department of Clinical Physiology of Vision, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Natalia V Neroeva
- Department of Pathology of the Retina and Optic Nerve, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Anastasia N Zhuravleva
- Department of Glaucoma, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Anna N Bogolepova
- Department of neurology, neurosurgery and medical genetics, Pirogov Russian National Research Medical University, Moscow, Russia
| | - Vladislav V Kotelin
- Department of Clinical Physiology of Vision, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Denis V Fadeev
- Scientific Experimental Center Department, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
| | - Irina V Tsapenko
- Department of Clinical Physiology of Vision, Helmholtz National Medical Research Center of Eye Diseases, Moscow, Russia
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Khabou H, Orendorff E, Trapani F, Rucli M, Desrosiers M, Yger P, Dalkara D, Marre O. Optogenetic targeting of AII amacrine cells restores retinal computations performed by the inner retina. Mol Ther Methods Clin Dev 2023; 31:101107. [PMID: 37868206 PMCID: PMC10589896 DOI: 10.1016/j.omtm.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 09/08/2023] [Indexed: 10/24/2023]
Abstract
Most inherited retinal dystrophies display progressive photoreceptor cell degeneration leading to severe visual impairment. Optogenetic reactivation of inner retinal neurons is a promising avenue to restore vision in retinas having lost their photoreceptors. Expression of optogenetic proteins in surviving ganglion cells, the retinal output, allows them to take on the lost photoreceptive function. Nonetheless, this creates an exclusively ON retina by expression of depolarizing optogenetic proteins in all classes of ganglion cells, whereas a normal retina extracts several features from the visual scene, with different ganglion cells detecting light increase (ON) and light decrease (OFF). Refinement of this therapeutic strategy should thus aim at restoring these computations. Here we used a vector that targets gene expression to a specific interneuron of the retina called the AII amacrine cell. AII amacrine cells simultaneously activate the ON pathway and inhibit the OFF pathway. We show that the optogenetic stimulation of AII amacrine cells allows restoration of both ON and OFF responses in the retina, but also mediates other types of retinal processing such as sustained and transient responses. Targeting amacrine cells with optogenetics is thus a promising avenue to restore better retinal function and visual perception in patients suffering from retinal degeneration.
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Affiliation(s)
- Hanen Khabou
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Elaine Orendorff
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Francesco Trapani
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Marco Rucli
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Melissa Desrosiers
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Pierre Yger
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Olivier Marre
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
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Santhanam A, Shihabeddin E, Wei H, Wu J, O'Brien J. Molecular basis of retinal remodeling in a zebrafish model of retinitis pigmentosa. Cell Mol Life Sci 2023; 80:362. [PMID: 37979052 PMCID: PMC10657301 DOI: 10.1007/s00018-023-05021-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 10/10/2023] [Accepted: 10/27/2023] [Indexed: 11/19/2023]
Abstract
A hallmark of inherited retinal degenerative diseases such as retinitis pigmentosa (RP) is progressive structural and functional remodeling of the remaining retinal cells as photoreceptors degenerate. Extensive remodeling of the retina stands as a barrier for the successful implementation of strategies to restore vision. To understand the molecular basis of remodeling, we performed analyses of single-cell transcriptome data from adult zebrafish retina of wild type AB strain (WT) and a P23H mutant rhodopsin transgenic model of RP with continuous degeneration and regeneration. Retinas from both female and male fish were pooled to generate each library, combining data from both sexes. We provide a benchmark atlas of retinal cell type transcriptomes in zebrafish and insight into how each retinal cell type is affected in the P23H model. Oxidative stress is found throughout the retina, with increases in reliance on oxidative metabolism and glycolysis in the affected rods as well as cones, bipolar cells, and retinal ganglion cells. There is also transcriptional evidence for widespread synaptic remodeling and enhancement of glutamatergic transmission in the inner retina. Notably, changes in circadian rhythm regulation are detected in cones, bipolar cells, and retinal pigmented epithelium. We also identify the transcriptomic signatures of retinal progenitor cells and newly formed rods essential for the regenerative process. This comprehensive transcriptomic analysis provides a molecular road map to understand how the retina remodels in the context of chronic retinal degeneration with ongoing regeneration.
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Affiliation(s)
- Abirami Santhanam
- Department of Ophthalmology & Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA.
- University of Houston College of Optometry, Houston, TX, 77204, USA.
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.
| | - Eyad Shihabeddin
- Department of Ophthalmology & Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
- MD Anderson UT Health Graduate School of Biomedical Sciences, Houston, TX, 77030, USA
| | - Haichao Wei
- Department of Neurosurgery, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Jiaqian Wu
- MD Anderson UT Health Graduate School of Biomedical Sciences, Houston, TX, 77030, USA
- Department of Neurosurgery, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - John O'Brien
- Department of Ophthalmology & Visual Science, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA.
- University of Houston College of Optometry, Houston, TX, 77204, USA.
- MD Anderson UT Health Graduate School of Biomedical Sciences, Houston, TX, 77030, USA.
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Lee EJ, Diaz-Aguilar MS, Min H, Choi J, Valdez Duran DA, Grandjean JM, Wiseman RL, Kroeger H, Lin JH. Mitochondria and Endoplasmic Reticulum Stress in Retinal Organoids from Patients with Vision Loss. THE AMERICAN JOURNAL OF PATHOLOGY 2023; 193:1721-1739. [PMID: 36535406 PMCID: PMC10616714 DOI: 10.1016/j.ajpath.2022.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/10/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022]
Abstract
Activating transcription factor 6 (ATF6), a key regulator of the unfolded protein response, plays a key role in endoplasmic reticulum function and protein homeostasis. Variants of ATF6 that abrogate transcriptional activity cause morphologic and molecular defects in cones, clinically manifesting as the human vision loss disease achromatopsia (ACHM). ATF6 is expressed in all retinal cells. However, the effect of disease-associated ATF6 variants on other retinal cell types remains unclear. Herein, this was investigated by analyzing bulk RNA-sequencing transcriptomes from retinal organoids generated from patients with ACHM, carrying homozygous loss-of-function ATF6 variants. Marked dysregulation in mitochondrial respiratory complex gene expression and disrupted mitochondrial morphology in ACHM retinal organoids were identified. This indicated that loss of ATF6 leads to previously unappreciated mitochondrial defects in the retina. Next, gene expression from control and ACHM retinal organoids were compared with transcriptome profiles of seven major retinal cell types generated from recent single-cell transcriptomic maps of nondiseased human retina. This indicated pronounced down-regulation of cone genes and up-regulation in Müller glia genes, with no significant effects on other retinal cells. Overall, the current analysis of ACHM patient retinal organoids identified new cellular and molecular phenotypes in addition to cone dysfunction: activation of Müller cells, increased endoplasmic reticulum stress, disrupted mitochondrial structure, and elevated respiratory chain activity gene expression.
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Affiliation(s)
- Eun-Jin Lee
- Department of Ophthalmology, Stanford University, Stanford, California; Department of Pathology, VA Palo Alto Healthcare System, Palo Alto, California; Department of Pathology, Stanford University, Stanford, California
| | - Monica S Diaz-Aguilar
- Department of Ophthalmology, Stanford University, Stanford, California; Department of Pathology, VA Palo Alto Healthcare System, Palo Alto, California; Department of Pathology, Stanford University, Stanford, California; Department of Medicine, Rush University Medical College, Chicago, Illinois
| | - Hyejung Min
- Department of Pathology, VA Palo Alto Healthcare System, Palo Alto, California; Department of Pathology, Stanford University, Stanford, California
| | - Jihee Choi
- Department of Pathology, Stanford University, Stanford, California
| | | | - Julia M Grandjean
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California
| | - R Luke Wiseman
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California
| | - Heike Kroeger
- Department of Cellular Biology, University of Georgia, Athens, Georgia
| | - Jonathan H Lin
- Department of Ophthalmology, Stanford University, Stanford, California; Department of Pathology, VA Palo Alto Healthcare System, Palo Alto, California; Department of Pathology, Stanford University, Stanford, California.
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9
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Kerschensteiner D. Losing, preserving, and restoring vision from neurodegeneration in the eye. Curr Biol 2023; 33:R1019-R1036. [PMID: 37816323 PMCID: PMC10575673 DOI: 10.1016/j.cub.2023.08.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
The retina is a part of the brain that sits at the back of the eye, looking out onto the world. The first neurons of the retina are the rod and cone photoreceptors, which convert changes in photon flux into electrical signals that are the basis of vision. Rods and cones are frequent targets of heritable neurodegenerative diseases that cause visual impairment, including blindness, in millions of people worldwide. This review summarizes the diverse genetic causes of inherited retinal degenerations (IRDs) and their convergence onto common pathogenic mechanisms of vision loss. Currently, there are few effective treatments for IRDs, but recent advances in disparate areas of biology and technology (e.g., genome editing, viral engineering, 3D organoids, optogenetics, semiconductor arrays) discussed here enable promising efforts to preserve and restore vision in IRD patients with implications for neurodegeneration in less approachable brain areas.
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Affiliation(s)
- Daniel Kerschensteiner
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Neuroscience, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO 63110, USA.
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10
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Schilardi G, Kralik J, Kleinlogel S. Selective Block of Upregulated Kv1.3 Potassium Channels in ON-Bipolar Cells of the Blind Retina Enhances Optogenetically Restored Signaling. Int J Mol Sci 2023; 24:14207. [PMID: 37762510 PMCID: PMC10531754 DOI: 10.3390/ijms241814207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 09/13/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
Loss of photoreceptors in retinal degenerative diseases also impacts the inner retina: bipolar cell dendrites retract, neurons rewire, and protein expression changes. ON-bipolar cells (OBCs) represent an attractive target for optogenetic vision restoration. However, the above-described maladaptations may negatively impact the quality of restored vision. To investigate this question, we employed human post-mortem retinas and transgenic rd1_Opto-mGluR6 mice expressing the optogenetic construct Opto-mGluR6 in OBCs and carrying the retinal degeneration rd1 mutation. We found significant changes in delayed rectifier potassium channel expression in OBCs of degenerative retinas. In particular, we found an increase in Kv1.3 expression already in early stages of degeneration. Immunohistochemistry localized Kv1.3 channels specifically to OBC axons. In whole-cell patch-clamp experiments, OBCs in the degenerated murine retina were less responsive, which could be reversed by application of the specific Kv1.3 antagonist Psora-4. Notably, Kv1.3 block significantly increased the amplitude and kinetics of Opto-mGluR6-mediated light responses in OBCs of the blind retina and increased the signal-to-noise ratio of light-triggered responses in retinal ganglion cells. We propose that reduction in Kv1.3 activity in the degenerated retina, either by pharmacological block or by KCNA3 gene silencing, could improve the quality of restored vision.
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11
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Kramer RH. Suppressing Retinal Remodeling to Mitigate Vision Loss in Photoreceptor Degenerative Disorders. Annu Rev Vis Sci 2023; 9:131-153. [PMID: 37713276 DOI: 10.1146/annurev-vision-112122-020957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/17/2023]
Abstract
Rod and cone photoreceptors degenerate in retinitis pigmentosa and age-related macular degeneration, robbing the visual system of light-triggered signals necessary for sight. However, changes in the retina do not stop with the photoreceptors. A stereotypical set of morphological and physiological changes, known as remodeling, occur in downstream retinal neurons. Some aspects of remodeling are homeostatic, with structural or functional changes compensating for partial loss of visual inputs. However, other aspects are nonhomeostatic, corrupting retinal information processing to obscure vision mediated naturally by surviving photoreceptors or artificially by vision-restoration technologies. In this review, I consider the mechanism of remodeling and its consequences for residual and restored visual function; discuss the role of retinoic acid, a critical molecular trigger of detrimental remodeling; and discuss strategies for suppressing retinoic acid biosynthesis or signaling as therapeutic possibilities for mitigating vision loss.
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Affiliation(s)
- Richard H Kramer
- Department of Molecular and Cell Biology, University of California, Berkeley, USA;
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12
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Díaz-Lezama N, Kajtna J, Wu J, Ayten M, Koch SF. Microglial and macroglial dynamics in a model of retinitis pigmentosa. Vision Res 2023; 210:108268. [PMID: 37295269 DOI: 10.1016/j.visres.2023.108268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 05/12/2023] [Accepted: 05/12/2023] [Indexed: 06/12/2023]
Abstract
In retinal degenerative diseases, such as retinitis pigmentosa (RP), the characteristic photoreceptor cell death is associated with changes of microglia and macroglia cells. Gene therapy, a promising treatment option for RP, is based on the premise that glial cell remodeling does not impact vision rescue. However, the dynamics of glial cells after treatment at late disease stages are not well understood. Here, we tested the reversibility of specific RP glia phenotypes in a Pde6b-deficient RP gene therapy mouse model. We demonstrated an increased number of activated microglia, retraction of microglial processes, reactive gliosis of Müller cells, astrocyte remodelling and an upregulation of glial fibrillary acidic protein (GFAP) in response to photoreceptor degeneration. Importantly, these changes returned to normal following rod rescue at late disease stages. These results suggest that therapeutic approaches restore the homeostasis between photoreceptors and glial cells.
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Affiliation(s)
- Nundehui Díaz-Lezama
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Jacqueline Kajtna
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Jiou Wu
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Monika Ayten
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Susanne F Koch
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany.
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13
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Parnami K, Bhattacharyya A. Current approaches to vision restoration using optogenetic therapy. Front Cell Neurosci 2023; 17:1236826. [PMID: 37663125 PMCID: PMC10469018 DOI: 10.3389/fncel.2023.1236826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 07/24/2023] [Indexed: 09/05/2023] Open
Abstract
Inherited progressive degeneration of photoreceptors such as retinitis pigmentosa (RP) is the most common cause of blindness leading to severe vision impairment affecting ~1 in 5,000 people worldwide. Although the function and morphology of the photoreceptors get disrupted, there is evidence that the inner retinal neurons such as bipolar cells and the retinal ganglion cells are left intact until later stages. Among several innovative therapeutic options aiming to restore vision, optogenetic therapy can bestow light sensitivity to remaining retinal neurons by ectopic expression of light-sensitive proteins. Since the advent of this technique, a diverse class of opsins (microbial and mammalian opsins), chimeric proteins, ligand-gated ion channels, and switchable opsins have been used to study their potential in vision restoration. These proteins differ in their excitation spectra, response kinetics, and signal amplification cascade. Although most of the studies have reported high fidelity of responses in the retina, only a handful of them have achieved functional vision in the visual cortex. This review is a summary of the visuocortical and behavioral responses after optogenetic treatment of the degenerated retina. This clarifies to what extent improved and meaningful vision can be obtained for therapeutic efficacy and continued clinical progress.
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14
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Wang H, Wang C, Zhang S, Liu J, Bi X. Impact of anti-VEGF therapy on distinctive retina layers in patients with macular edema secondary to branch retinal vein occlusion. BMC Ophthalmol 2023; 23:235. [PMID: 37231357 DOI: 10.1186/s12886-023-02981-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 05/18/2023] [Indexed: 05/27/2023] Open
Abstract
BACKGROUND To explore the impact of anti-vascular epithelial growth factor (ant-VEGF) on the thickness of each retinal layer in patients with macular edema (ME) secondary to the branch retinal vein occlusion (BRVO). METHODS This retrospective study included patients with ME secondary to monocular BRVO who received anti-VEGF therapy in Ningxia Eye Hospital between January-December 2020. RESULTS Forty-three patients (25 males) were included, with 31 showed > 25% reduction in central retinal thickness (CRT) after anti-VEGF therapy (response group), and the others showed a ≤25% reduction in CRT (no-response group). The response group showed significantly smaller mean changes in the ganglion cell layer (GCL) (after 2 months) and inner plexiform layer (IPL) (after 1, 2, and 3 months) and significantly greater mean changes in the inner nuclear layer (INL) (after 2 and 3 months), outer plexiform layer (OPL) (after 3 months), outer nuclear layer (ONL) (after 2 and 3 months), and CRT (after 1 and 2 months) (all P < 0.05) as compared to the no-response group. The mean change in the thickness of each retinal layer IPL (P = 0.006) between the two groups was significantly different after controlling for a time and with a significant time trend (P < 0.001). Additionally, patients in the response group were more likely to have an improvement in IPL (43.68 ± 6.01 at 1 month and 41.52 ± 5.45 at 2 months vs. 39.9 ± 6.86 at baseline) after anti-VEGF therapy, while those in no response group might show improvement in GCL (45.75 ± 8.24 at 1 month, 40.00 ± 8.92 at 2 months, and 38.83 ± 9.93 at 3 months vs. 49.67 ± 6.83 at baseline). CONCLUSIONS Anti-VEGF therapy might help restore the retinal structure and function in patients with ME secondary to BRVO, and those who have a response after anti-VEGF therapy are more likely to improve IPL, while those having no response might show improvement in GCL.
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Affiliation(s)
- Hui Wang
- Ophthalmology Center of Changzhi People's Hospital affiliated to Changzhi Medical College, Changzhi City, China
| | - Chanjuan Wang
- Ningxia Eye Hospital, People Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University for Nationalities), Yinchuan, 750000, China
| | - Shaochi Zhang
- Ningxia Eye Hospital, People Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University for Nationalities), Yinchuan, 750000, China
| | - Jun Liu
- Ophthalmology Center of Changzhi People's Hospital affiliated to Changzhi Medical College, Changzhi City, China
| | - Xiaojun Bi
- Ningxia Eye Hospital, People Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University for Nationalities), Yinchuan, 750000, China.
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15
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Pfeiffer RL, Jones BW. Retinal Pathoconnectomics: A Window into Neurodegeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:297-301. [PMID: 37440048 PMCID: PMC11342915 DOI: 10.1007/978-3-031-27681-1_43] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Over the past decade, the field of retinal connectomics has made huge strides in describing the precise topologies underlying retinal visual processing. The same techniques that allowed these advancements are also applicable to understanding the progression of rewiring in retinal remodeling: retinal pathoconnectomics. Pathoconnectomics is unique in its unbiased approach to understanding the impacts of deafferentation on the remaining network components and identifying aberrant connectivities leading to visual processing defects. Pathoconnectomics also paves the way for identifying underlying rules of rewiring that may be recapitulated throughout the nervous system in other neurodegenerative diseases.
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Affiliation(s)
- Rebecca L Pfeiffer
- John A. Moran Eye Center, Department of Ophthalmology, University of Utah, Salt Lake City, UT, USA.
| | - Bryan W Jones
- John A. Moran Eye Center, Department of Ophthalmology, University of Utah, Salt Lake City, UT, USA
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16
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Leinonen H, Fu Z, Bull E. Neural and Müller glial adaptation of the retina to photoreceptor degeneration. Neural Regen Res 2023; 18:701-707. [DOI: 10.4103/1673-5374.354511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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17
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Pfeiffer RL, Jones BW. Current perspective on retinal remodeling: Implications for therapeutics. Front Neuroanat 2022; 16:1099348. [PMID: 36620193 PMCID: PMC9813390 DOI: 10.3389/fnana.2022.1099348] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
The retinal degenerative diseases retinitis pigmentosa and age-related macular degeneration are a leading cause of irreversible vision loss. Both present with progressive photoreceptor degeneration that is further complicated by processes of retinal remodeling. In this perspective, we discuss the current state of the field of retinal remodeling and its implications for vision-restoring therapeutics currently in development. Here, we discuss the challenges and pitfalls retinal remodeling poses for each therapeutic strategy under the premise that understanding the features of retinal remodeling in totality will provide a basic framework with which therapeutics can interface. Additionally, we discuss the potential for approaching therapeutics using a combined strategy of using diffusible molecules in tandem with other vision-restoring therapeutics. We end by discussing the potential of the retina and retinal remodeling as a model system for more broadly understanding the progression of neurodegeneration across the central nervous system.
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18
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Scalabrino ML, Thapa M, Chew LA, Zhang E, Xu J, Sampath AP, Chen J, Field GD. Robust cone-mediated signaling persists late into rod photoreceptor degeneration. eLife 2022; 11:e80271. [PMID: 36040015 PMCID: PMC9560159 DOI: 10.7554/elife.80271] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/25/2022] [Indexed: 01/13/2023] Open
Abstract
Rod photoreceptor degeneration causes deterioration in the morphology and physiology of cone photoreceptors along with changes in retinal circuits. These changes could diminish visual signaling at cone-mediated light levels, thereby limiting the efficacy of treatments such as gene therapy for rescuing normal, cone-mediated vision. However, the impact of progressive rod death on cone-mediated signaling remains unclear. To investigate the fidelity of retinal ganglion cell (RGC) signaling throughout disease progression, we used a mouse model of rod degeneration (Cngb1neo/neo). Despite clear deterioration of cone morphology with rod death, cone-mediated signaling among RGCs remained surprisingly robust: spatiotemporal receptive fields changed little and the mutual information between stimuli and spiking responses was relatively constant. This relative stability held until nearly all rods had died and cones had completely lost well-formed outer segments. Interestingly, RGC information rates were higher and more stable for natural movies than checkerboard noise as degeneration progressed. The main change in RGC responses with photoreceptor degeneration was a decrease in response gain. These results suggest that gene therapies for rod degenerative diseases are likely to prolong cone-mediated vision even if there are changes to cone morphology and density.
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Affiliation(s)
- Miranda L Scalabrino
- Department of Neurobiology, Duke University School of MedicineDurhamUnited States
| | - Mishek Thapa
- Department of Neurobiology, Duke University School of MedicineDurhamUnited States
| | - Lindsey A Chew
- Department of Neurobiology, Duke University School of MedicineDurhamUnited States
| | - Esther Zhang
- Department of Neurobiology, Duke University School of MedicineDurhamUnited States
| | - Jason Xu
- Department of Statistical Science, Duke UniversityDurhamUnited States
| | - Alapakkam P Sampath
- Jules Stein Eye Institute, University of California, Los AngelesLos AngelesUnited States
| | - Jeannie Chen
- Zilkha Neurogenetics Institute, Keck School of Medicine, University of Southern CaliforniaLos AngelesUnited States
| | - Greg D Field
- Department of Neurobiology, Duke University School of MedicineDurhamUnited States
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19
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Jung R, Kelbsch C, Wilhelm H, Wilhelm B, Strasser T, Peters T, Kempf M, Kortüm F, Pohl L, Stingl K, Stingl K. Cell-specific electrical stimulation of human retinal neurons assessed by pupillary response dynamics in vivo. Exp Eye Res 2022; 222:109185. [PMID: 35850172 DOI: 10.1016/j.exer.2022.109185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 06/12/2022] [Accepted: 07/05/2022] [Indexed: 11/30/2022]
Abstract
Studies on the electrical excitability of retinal neurons show that photoreceptors and other cell types can be selectively activated by distinct stimulation frequencies in vitro. Yet, this principle still needs to be validated in humans in vivo. As a first step, this study explored the frequency preferences of human rods by means of transcorneal electrostimulation (TES), using the electrically-elicited pupillary responses (EEPRs) as an objective readout. The stimulation paradigm contained a 1.2 Hz sinusoidal envelope, which was superimposed on variable carrier frequencies (4-30 Hz). These currents were delivered to one of the participant's eyes via a corneal electrode and consensual pupillary reactions were recorded from the contralateral eye. The responsiveness of the retina at each frequency was assessed based on the EEPR dynamics. Differences between healthy participants and patients with retinitis pigmentosa were evaluated to identify the preferred frequency range of rods. The responsiveness of healthy individuals revealed a clear peak around 6-8 Hz. In contrast, the pupillary responses of patients were significantly reduced in the lower frequency range. These findings suggest that the responses in this frequency bin were selectively mediated by rods. This work provides evidence that different retinal cell types can be selectively activated via TES in vivo, and that this effect can be captured noninvasively using EEPRs. This knowledge may be exploited for the diagnostics and therapy of retinal diseases, e.g., to design cell-specific functional tests for the degenerating retina, or to optimize stimulation paradigms which are currently used by retinal prostheses.
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Affiliation(s)
- Ronja Jung
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany.
| | - Carina Kelbsch
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany; Pupil Research Group, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany
| | - Helmut Wilhelm
- Pupil Research Group, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany
| | - Barbara Wilhelm
- Pupil Research Group, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany
| | - Torsten Strasser
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany; Pupil Research Group, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany; Institute for Ophthalmic Research, University of Tübingen, 72076, Tübingen, Germany
| | - Tobias Peters
- Pupil Research Group, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany
| | - Melanie Kempf
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany; Center for Rare Diseases, University of Tübingen, 72076, Tübingen, Germany
| | - Friederike Kortüm
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany
| | - Lisa Pohl
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany
| | - Krunoslav Stingl
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany; Pupil Research Group, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany; Center for Rare Diseases, University of Tübingen, 72076, Tübingen, Germany
| | - Katarina Stingl
- University Eye Hospital, Center for Ophthalmology, University of Tuebingen, 72076, Tuebingen, Germany; Center for Rare Diseases, University of Tübingen, 72076, Tübingen, Germany
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20
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Francia S, Shmal D, Di Marco S, Chiaravalli G, Maya-Vetencourt JF, Mantero G, Michetti C, Cupini S, Manfredi G, DiFrancesco ML, Rocchi A, Perotto S, Attanasio M, Sacco R, Bisti S, Mete M, Pertile G, Lanzani G, Colombo E, Benfenati F. Light-induced charge generation in polymeric nanoparticles restores vision in advanced-stage retinitis pigmentosa rats. Nat Commun 2022; 13:3677. [PMID: 35760799 PMCID: PMC9237035 DOI: 10.1038/s41467-022-31368-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 06/14/2022] [Indexed: 12/16/2022] Open
Abstract
Retinal dystrophies such as Retinitis pigmentosa are among the most prevalent causes of inherited legal blindness, for which treatments are in demand. Retinal prostheses have been developed to stimulate the inner retinal network that, initially spared by degeneration, deteriorates in the late stages of the disease. We recently reported that conjugated polymer nanoparticles persistently rescue visual activities after a single subretinal injection in the Royal College of Surgeons rat model of Retinitis pigmentosa. Here we demonstrate that conjugated polymer nanoparticles can reinstate physiological signals at the cortical level and visually driven activities when microinjected in 10-months-old Royal College of Surgeons rats bearing fully light-insensitive retinas. The extent of visual restoration positively correlates with the nanoparticle density and hybrid contacts with second-order retinal neurons. The results establish the functional role of organic photovoltaic nanoparticles in restoring visual activities in fully degenerate retinas with intense inner retina rewiring, a stage of the disease in which patients are subjected to prosthetic interventions. Retinal dystrophies such as Retinitis pigmentosa are among the most prevalent causes of inherited incurable legal blindness. Here the authors demonstrate that conjugated polymer nanoparticles reinstate visual functions in aged rats with fully degenerated and rewired retinas.
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Affiliation(s)
- S Francia
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - D Shmal
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Experimental Medicine, University of Genova, Genova, Italy
| | - S Di Marco
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - G Chiaravalli
- Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, Milano, Italy
| | - J F Maya-Vetencourt
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Biology, University of Pisa, Pisa, Italy
| | - G Mantero
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Experimental Medicine, University of Genova, Genova, Italy
| | - C Michetti
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Experimental Medicine, University of Genova, Genova, Italy
| | - S Cupini
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,Department of Experimental Medicine, University of Genova, Genova, Italy
| | - G Manfredi
- Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, Milano, Italy.,Novavido s.r.l., Bologna, Italy
| | - M L DiFrancesco
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - A Rocchi
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy
| | - S Perotto
- Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, Milano, Italy
| | - M Attanasio
- Department of Ophthalmology, IRCCS Sacrocuore Don Calabria Hospital, Negrar, Verona, Italy
| | - R Sacco
- Department of Mathematics, Politecnico di Milano, Milano, Italy
| | - S Bisti
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy
| | - M Mete
- Department of Ophthalmology, IRCCS Sacrocuore Don Calabria Hospital, Negrar, Verona, Italy
| | - G Pertile
- Department of Ophthalmology, IRCCS Sacrocuore Don Calabria Hospital, Negrar, Verona, Italy
| | - G Lanzani
- Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, Milano, Italy. .,Department of Physics, Politecnico di Milano, Milan, Italy.
| | - E Colombo
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy.,IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - F Benfenati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova, Italy. .,IRCCS Ospedale Policlinico San Martino, Genova, Italy.
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21
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Wu J, Rountree CM, Kare SS, Ramkumar PK, Finan JD, Troy JB. Progress on Designing a Chemical Retinal Prosthesis. Front Cell Neurosci 2022; 16:898865. [PMID: 35774083 PMCID: PMC9239740 DOI: 10.3389/fncel.2022.898865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 05/17/2022] [Indexed: 11/29/2022] Open
Abstract
The last major review of progress toward a chemical retinal prosthesis was a decade ago. Many important advancements have been made since then with the aim of producing an implantable device for animal testing. We review that work here discussing the potential advantages a chemical retinal prosthesis may possess, the spatial and temporal resolutions it might provide, the materials from which an implant might be constructed and its likely effectiveness in stimulating the retina in a natural fashion. Consideration is also given to implant biocompatibility, excitotoxicity of dispensed glutamate and known changes to photoreceptor degenerate retinas.
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Affiliation(s)
- Jiajia Wu
- Department of Biomedical Engineering, Robert R. McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL, United States
| | - Corey M. Rountree
- Department of Mechanical and Industrial Engineering, College of Engineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Sai-Siva Kare
- Department of Mechanical and Industrial Engineering, College of Engineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Pradeep Kumar Ramkumar
- Department of Mechanical and Industrial Engineering, College of Engineering, University of Illinois at Chicago, Chicago, IL, United States
| | - John D. Finan
- Department of Mechanical and Industrial Engineering, College of Engineering, University of Illinois at Chicago, Chicago, IL, United States
| | - John B. Troy
- Department of Biomedical Engineering, Robert R. McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL, United States
- *Correspondence: John B. Troy,
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22
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Schilardi G, Kleinlogel S. Two Functional Classes of Rod Bipolar Cells in the Healthy and Degenerated Optogenetically Treated Murine Retina. Front Cell Neurosci 2022; 15:809531. [PMID: 35095426 PMCID: PMC8793500 DOI: 10.3389/fncel.2021.809531] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/20/2021] [Indexed: 11/25/2022] Open
Abstract
Bipolar cells have become successful targets for optogenetic gene therapies that restore vision after photoreceptor degeneration. However, degeneration was shown to cause changes in neuronal connectivity and protein expression, which may impact the quality of synthetically restored signaling. Further, the expression of an optogenetic protein may alter passive membrane properties of bipolar cells affecting signal propagation. We here investigated the passive membrane properties of rod bipolar cells in three different systems, the healthy retina, the degenerated retina, and the degenerated retina expressing the optogenetic actuator Opto-mGluR6. We found that, based on the shape of their current-voltage relations, rod bipolar cells in healthy and degenerated retinas form two clear functional groups (type 1 and type 2 cells). Depolarizing the membrane potential changed recorded current-voltage curves from type 1 to type 2, confirming a single cell identity with two functional states. Expression of Opto-mGluR6 did not alter the passive properties of the rod bipolar cell. With progressing degeneration, dominant outward rectifying currents recorded in type 2 rod bipolar cells decreased significantly. We demonstrate that this is caused by a downregulation of BK channel expression in the degenerated retina. Since this BK conductance will normally recover the membrane potential after RBCs are excited by open TRPM1 channels, a loss in BK will decrease high-pass filtering at the rod bipolar cell level. A better understanding of the changes of bipolar cell physiology during retinal degeneration may pave the way to optimize future treatment strategies of blindness.
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23
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Kim JM, Lee M, Lim HB, Won YK, Shin Y, Lee W, Kim J. Longitudinal changes in the ganglion cell-inner plexiform layer thickness of age-related macular degeneration. Acta Ophthalmol 2021; 99:e1056-e1062. [PMID: 33555661 DOI: 10.1111/aos.14784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 11/22/2020] [Accepted: 01/12/2021] [Indexed: 11/28/2022]
Abstract
PURPOSE To determine longitudinal changes of the ganglion cell-inner plexiform layer (GC-IPL) thickness in patients with non-exudative age-related macular degeneration (AMD) without other ophthalmic disease. METHODS Thirty-three eyes of 33 patients with early and intermediate non-exudative AMD (non-exudative AMD group) and 33 normal control eyes were followed for 2 years, and GC-IPL thickness was measured by spectral domain optical coherence tomography at 1-year intervals. The mean rate of GC-IPL reduction was estimated using a linear mixed model and compared between two groups. RESULTS The mean age of patients in the non-exudative AMD group and control groups were 68.82 ± 6.81 years and 67.73 ± 5.87 years, respectively (p = 0.488). The mean GC-IPL thickness at the first visit was 76.61 ± 16.33 μm in the non-exudative AMD and 81.76 ± 3.69 μm in control group (p = 0.387), and these values significantly decreased over time, with an average reduction rate of average GC-IPL -0.86 μm/year in the non-exudative AMD group and -0.32 μm/year in the control group. The difference between two groups was statistically significant (p < 0.001), and there was also a significant interaction between group and duration in linear mixed models in mean GC-IPL thickness (p = 0.001). CONCLUSIONS The reduction rate of the GC-IPL thickness was greater in non-exudative AMD eyes, even at relatively early stages of the disease. Physicians should maintain awareness of the presence of non-exudative AMD in various cases of ophthalmic diseases where GC-IPL thickness evaluation is necessary.
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Affiliation(s)
- Ju Mi Kim
- Department of Ophthalmology Chungnam National University College of Medicine Daejeon Korea
| | - Min‐Woo Lee
- Department of Ophthalmology Konyang University college of medicine Daejeon Korea
| | - Hyung Bin Lim
- Department of Ophthalmology Chungnam National University College of Medicine Daejeon Korea
| | - Yeo Kyoung Won
- Department of Ophthalmology Chungnam National University College of Medicine Daejeon Korea
| | - Yong‐il Shin
- Department of Ophthalmology Chungnam National University College of Medicine Daejeon Korea
| | - Woo‐Hyuck Lee
- Department of Ophthalmology Chungnam National University College of Medicine Daejeon Korea
| | - Jung‐Yeul Kim
- Department of Ophthalmology Chungnam National University College of Medicine Daejeon Korea
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24
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Abstract
Our sense of sight relies on photoreceptors, which transduce photons into the nervous system's electrochemical interpretation of the visual world. These precious photoreceptors can be disrupted by disease, injury, and aging. Once photoreceptors start to die, but before blindness occurs, the remaining retinal circuitry can withstand, mask, or exacerbate the photoreceptor deficit and potentially be receptive to newfound therapies for vision restoration. To maximize the retina's receptivity to therapy, one must understand the conditions that influence the state of the remaining retina. In this review, we provide an overview of the retina's structure and function in health and disease. We analyze a collection of observations on photoreceptor disruption and generate a predictive model to identify parameters that influence the retina's response. Finally, we speculate on whether the retina, with its remarkable capacity to function over light levels spanning nine orders of magnitude, uses these same adaptational mechanisms to withstand and perhaps mask photoreceptor loss.
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Affiliation(s)
- Joo Yeun Lee
- Department of Ophthalmology, University of California, San Francisco, California 94143, USA; , , ,
| | - Rachel A Care
- Department of Ophthalmology, University of California, San Francisco, California 94143, USA; , , ,
| | - Luca Della Santina
- Department of Ophthalmology, University of California, San Francisco, California 94143, USA; , , ,
- Bakar Computational Health Sciences Institute, University of California, San Francisco, California 94143, USA
| | - Felice A Dunn
- Department of Ophthalmology, University of California, San Francisco, California 94143, USA; , , ,
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25
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Riccitelli S, Di Paolo M, Ashley J, Bisti S, Di Marco S. The Timecourses of Functional, Morphological, and Molecular Changes Triggered by Light Exposure in Sprague-Dawley Rat Retinas. Cells 2021; 10:1561. [PMID: 34205615 PMCID: PMC8234029 DOI: 10.3390/cells10061561] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 06/01/2021] [Accepted: 06/16/2021] [Indexed: 01/11/2023] Open
Abstract
Retinal neurodegeneration can impair visual perception at different levels, involving not only photoreceptors, which are the most metabolically active cells, but also the inner retina. Compensatory mechanisms may hide the first signs of these impairments and reduce the likelihood of receiving timely treatments. Therefore, it is essential to characterize the early critical steps in the neurodegenerative progression to design adequate therapies. This paper describes and correlates early morphological and biochemical changes in the degenerating retina with in vivo functional analysis of retinal activity and investigates the progression of neurodegenerative stages for up to 7 months. For these purposes, Sprague-Dawley rats were exposed to 1000 lux light either for different durations (12 h to 24 h) and examined seven days afterward (7d) or for a fixed duration (24 h) and monitored at various time points following the exposure (up to 210d). Flash electroretinogram (fERG) recordings were correlated with morphological and histological analyses to evaluate outer and inner retinal disruptions, gliosis, trophic factor release, and microglial activation. Twelve hours or fifteen hours of exposure to constant light led to a severe retinal dysfunction with only minor morphological changes. Therefore, early pathological signs might be hidden by compensatory mechanisms that silence retinal dysfunction, accounting for the discrepancy between photoreceptor loss and retinal functional output. The long-term analysis showed a transient functional recovery, maximum at 45 days, despite a progressive loss of photoreceptors and coincident increases in glial fibrillary acidic protein (GFAP) and basic fibroblast growth factor-2 (bFGF-2) expression. Interestingly, the progression of the disease presented different patterns in the dorsal and ventral retina. The information acquired gives us the potential to develop a specific diagnostic tool to monitor the disease's progression and treatment efficacy.
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Affiliation(s)
- Serena Riccitelli
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy; (S.R.); (M.D.P.); (S.B.)
| | - Mattia Di Paolo
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy; (S.R.); (M.D.P.); (S.B.)
| | - James Ashley
- School of Biological Sciences, The University of Manchester, Manchester M13 9PL, UK;
| | - Silvia Bisti
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy; (S.R.); (M.D.P.); (S.B.)
- Istituto Nazionale di Biostrutture e Biosistemi (INBB), 00136 Roma, Italy
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, 16132 Genova, Italy
| | - Stefano Di Marco
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy; (S.R.); (M.D.P.); (S.B.)
- Istituto Nazionale di Biostrutture e Biosistemi (INBB), 00136 Roma, Italy
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, 16132 Genova, Italy
- IRCCS, Ospedale Policlinico San Martino, 16132 Genova, Italy
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26
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Nemitz L, Dedek K, Janssen-Bienhold U. Synaptic Remodeling in the Cone Pathway After Early Postnatal Horizontal Cell Ablation. Front Cell Neurosci 2021; 15:657594. [PMID: 34122012 PMCID: PMC8187617 DOI: 10.3389/fncel.2021.657594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 05/03/2021] [Indexed: 11/30/2022] Open
Abstract
The first synapse of the visual pathway is formed by photoreceptors, horizontal cells and bipolar cells. While ON bipolar cells invaginate into the photoreceptor terminal and form synaptic triads together with invaginating horizontal cell processes, OFF bipolar cells make flat contacts at the base of the terminal. When horizontal cells are ablated during retina development, no invaginating synapses are formed in rod photoreceptors. However, how cone photoreceptors and their synaptic connections with bipolar cells react to this insult, is unclear so far. To answer this question, we specifically ablated horizontal cells from the developing mouse retina. Following ablation around postnatal day 4 (P4)/P5, cones initially exhibited a normal morphology and formed flat contacts with OFF bipolar cells, but only few invaginating contacts with ON bipolar cells. From P15 on, synaptic remodeling became obvious with clustering of cone terminals and mislocalized cone somata in the OPL. Adult cones (P56) finally displayed highly branched axons with numerous terminals which contained ribbons and vesicular glutamate transporters. Furthermore, type 3a, 3b, and 4 OFF bipolar cell dendrites sprouted into the outer nuclear layer and even expressed glutamate receptors at the base of newly formed cone terminals. These results indicate that cones may be able to form new synapses with OFF bipolar cells in adult mice. In contrast, cone terminals lost their invaginating contacts with ON bipolar cells, highlighting the importance of horizontal cells for synapse maintenance. Taken together, our data demonstrate that early postnatal horizontal cell ablation leads to differential remodeling in the cone pathway: whereas synapses between cones and ON bipolar cells were lost, new putative synapses were established between cones and OFF bipolar cells. These results suggest that synapse formation and maintenance are regulated very differently between flat and invaginating contacts at cone terminals.
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Affiliation(s)
- Lena Nemitz
- Visual Neuroscience, Department of Neuroscience, University of Oldenburg, Oldenburg, Germany
| | - Karin Dedek
- Animal Navigation/Neurosensorics, Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - Ulrike Janssen-Bienhold
- Visual Neuroscience, Department of Neuroscience, University of Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
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27
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Xu S, Zhang P, Zhang M, Wang X, Li G, Xu G, Ni Y. Synaptic changes and the response of microglia in a light-induced photoreceptor degeneration model. Mol Vis 2021; 27:206-220. [PMID: 33967574 PMCID: PMC8100860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 04/29/2021] [Indexed: 11/15/2022] Open
Abstract
Purpose To explore synaptic changes and the response of microglia in a light-induced photoreceptor degeneration model. Methods Sprague-Dawley rats were euthanized 1 h, 1 day, 3 days, 7 days, and 14 days after being exposed to intense blue light for 24 h. Hematoxylin and eosin (H&E) and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining were used to evaluate changes in the outer nuclear layer (ONL). Transmission electron microscopy (TEM) was applied to observe the ultrastructural changes in the synapses between the photoreceptors and second-order neurons. Western blotting was conducted to evaluate specific proteins, including postsynaptic density-95 (PSD-95), metabotropic glutamate receptor 6 (mGluR6), synapsin I, and synaptophysin. Immunofluorescence of CD11b and PKC-α or mGluR6 was used to explore the spatial relationships between microglial processes and synaptic elements. Immunoelectron microscopy of PSD-95 was performed to further confirm its engulfment of synaptic materials. Results H&E and TUNEL staining showed that the thickness of the ONL decreased markedly, and the number of apoptotic photoreceptors peaked at day 1. TEM revealed darkened photoreceptor terminals and that ribbons of them were floating in the cytoplasm, coinciding with the downregulation of PSD-95 and mGluR6. Downstream synaptic protein synapsin I and synaptophysin exhibited upregulation in the inner plexiform layer. Activated microglia migrated to the outer retina, and their processes were found in close proximity to synapses in the outer plexiform layer under light and electron microscopy levels. Double immunostaining of CD11b and mGluR6 showed colocalization. PSD-95-immunoreactive electron-dense materials were observed inside the microglia suggesting engulfment of synaptic components. Conclusions The study showed that there are early synaptic impairment and late compensatory changes in downstream synapses in this photic injury model. Activated microglia touched and directly engulfed synaptic materials. Microglia may play a role or a partial role in synaptic changes.
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Affiliation(s)
- Sisi Xu
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China,Key NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Peijun Zhang
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China,Key NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Meng Zhang
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China,Key NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Xin Wang
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China,Key NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Gang Li
- Research Center, Eye & ENT Hospital of Fudan University, Shanghai, China
| | - Gezhi Xu
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China,Key NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Yingqin Ni
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China,Key NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
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28
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Li S, Datta S, Brabbit E, Love Z, Woytowicz V, Flattery K, Capri J, Yao K, Wu S, Imboden M, Upadhyay A, Arumugham R, Thoreson WB, DeAngelis MM, Haider NB. Nr2e3 is a genetic modifier that rescues retinal degeneration and promotes homeostasis in multiple models of retinitis pigmentosa. Gene Ther 2021; 28:223-241. [PMID: 32123325 PMCID: PMC7483267 DOI: 10.1038/s41434-020-0134-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 02/05/2020] [Accepted: 02/18/2020] [Indexed: 12/21/2022]
Abstract
Recent advances in viral vector engineering, as well as an increased understanding of the cellular and molecular mechanism of retinal diseases, have led to the development of novel gene therapy approaches. Furthermore, ease of accessibility and ocular immune privilege makes the retina an ideal target for gene therapies. In this study, the nuclear hormone receptor gene Nr2e3 was evaluated for efficacy as broad-spectrum therapy to attenuate early to intermediate stages of retinal degeneration in five unique mouse models of retinitis pigmentosa (RP). RP is a group of heterogenic inherited retinal diseases associated with over 150 gene mutations, affecting over 1.5 million individuals worldwide. RP varies in age of onset, severity, and rate of progression. In addition, ~40% of RP patients cannot be genetically diagnosed, confounding the ability to develop personalized RP therapies. Remarkably, Nr2e3 administered therapy resulted in reduced retinal degeneration as observed by increase in photoreceptor cells, improved electroretinogram, and a dramatic molecular reset of key transcription factors and associated gene networks. These therapeutic effects improved retinal homeostasis in diseased tissue. Results of this study provide evidence that Nr2e3 can serve as a broad-spectrum therapy to treat multiple forms of RP.
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Affiliation(s)
- Sujun Li
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Shyamtanu Datta
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Emily Brabbit
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Zoe Love
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Victoria Woytowicz
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Kyle Flattery
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Jessica Capri
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Katie Yao
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Siqi Wu
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | | | | | | | - Wallace B Thoreson
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, USA
| | | | - Neena B Haider
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA.
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29
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Gilhooley MJ, Hickey DG, Lindner M, Palumaa T, Hughes S, Peirson SN, MacLaren RE, Hankins MW. ON-bipolar cell gene expression during retinal degeneration: Implications for optogenetic visual restoration. Exp Eye Res 2021; 207:108553. [PMID: 33811915 PMCID: PMC8214074 DOI: 10.1016/j.exer.2021.108553] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 03/08/2021] [Accepted: 03/23/2021] [Indexed: 12/28/2022]
Abstract
Purpose Retinal bipolar cells survive even in the later stages of inherited retinal degenerations (IRDs) and so are attractive targets for optogenetic approaches to vision restoration. However, it is not known to what extent the remodelling that these cells undergo during degeneration affects their function. Specifically, it is unclear if they are free from metabolic stress, receptive to adeno-associated viral vectors, suitable for opsin-based optogenetic tools and able to propagate signals by releasing neurotransmitter. Methods Fluorescence activated cell sorting (FACS) was performed to isolate labelled bipolar cells from dissociated retinae of litter-mates with or without the IRD mutation Pde6brd1/rd1 selectively expressing an enhanced yellow fluorescent protein (EYFP) as a marker in ON-bipolar cells. Subsequent mRNA extraction allowed Illumina® microarray comparison of gene expression in bipolar cells from degenerate to those of wild type retinae. Changes in four candidate genes were further investigated at the protein level using retinal immunohistochemistry over the course of degeneration. Results A total of sixty differentially expressed transcripts reached statistical significance: these did not include any genes directly associated with native primary bipolar cell signalling, nor changes consistent with metabolic stress. Four significantly altered genes (Srm2, Slf2, Anxa7 & Cntn1), implicated in synaptic remodelling, neurotransmitter release and viral vector entry had immunohistochemical staining colocalising with ON-bipolar cell markers and varying over the course of degeneration. Conclusion Our findings suggest relatively few gene expression changes in the context of degeneration: that despite remodelling, bipolar cells are likely to remain viable targets for optogenetic vision restoration. In addition, several genes where changes were seen could provide a basis for investigations to enhance the efficacy of optogenetic therapies. Bipolar cells are attractive targets for therapeutic optogenetics in IRDs. This is the first cell specific transcriptomic analysis of bipolar cells in an IRD model. Bipolar cells maintain expression of genes essential to act as targets for optogenetics. Protein staining relating to four candidate genes (Anxa7, Cntn1, Srm2, Sulf2) is confirmed using immunohistochemistry.
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Affiliation(s)
- Michael J Gilhooley
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, OX1 3RE, United Kingdom; The Oxford Eye Hospital, Oxford, OX3 9DU, United Kingdom; Moorfields Eye Hospital, London, EC1V 2PD, United Kingdom
| | - Doron G Hickey
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, OX1 3RE, United Kingdom; Royal Victorian Eye and Ear Hospital, Melbourne, 002, Australia
| | - Moritz Lindner
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, OX1 3RE, United Kingdom; The Oxford Eye Hospital, Oxford, OX3 9DU, United Kingdom; Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps University, Deutschhausstrasse 1-2, Marburg, 35037, Germany
| | - Teele Palumaa
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, OX1 3RE, United Kingdom
| | - Steven Hughes
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, OX1 3RE, United Kingdom; Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, OX1 3RE, United Kingdom
| | - Stuart N Peirson
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, OX1 3RE, United Kingdom
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, OX1 3RE, United Kingdom; The Oxford Eye Hospital, Oxford, OX3 9DU, United Kingdom; Moorfields Eye Hospital, London, EC1V 2PD, United Kingdom
| | - Mark W Hankins
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, OX1 3RE, United Kingdom; Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, OX1 3RE, United Kingdom.
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30
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Park SJ, Woon QTS, Er JC, Wong BH, Liu X, Kang NY, Barathi VA, Silver DL, Chang YT. Application of Neuron-Selective Fluorescent Probe, NeuA, To Identify Mouse Retinal Degeneration. Chembiochem 2021; 22:1915-1919. [PMID: 33617145 DOI: 10.1002/cbic.202100011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 02/20/2021] [Indexed: 11/09/2022]
Abstract
The retina is part of the central nerve system (CNS) and has various interneurons and sensory neurons such as photoreceptor cells. Retinitis pigmentosa (RP) is an inherited condition that is characterized by photoreceptor degeneration. Herein, we developed a fluorescent probe-NeuA-for detecting retinal neuronal cells and applied NeuA to discriminate between healthy and RP retinas. The staining pattern of NeuA in the retinas of healthy and RP mouse models was examined in vitro, ex vivo and in vivo using confocal microscopy, the fluorescent fundus microscopy and optical coherent tomography (OCT). NeuA strongly stained the outer segment layer of photoreceptor cells and some bipolar cells in the healthy retina, but there was only weak staining in the photoreceptor degenerated retinas. Therefore, NeuA probe can be used as the detecting RP tools in the preclinical conditions.
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Affiliation(s)
- Sung-Jin Park
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, 138667, Republic of Singapore
| | - Queenie Tan Shu Woon
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore, 169856, Republic of Singapore
| | - Jun Cheng Er
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, 138667, Republic of Singapore
| | - Bernice H Wong
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, 169857, Republic of Singapore
| | - Xiao Liu
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Nam-Young Kang
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, 138667, Republic of Singapore.,Department of Creative IT Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Veluchamy A Barathi
- Singapore Eye Research Institute, Singapore, 169856, Republic of Singapore.,Eye-ACP, Duke-NUS Graduate Medical School, Singapore, 169857, Republic of Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119228, Republic of Singapore
| | - David L Silver
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, 169857, Republic of Singapore
| | - Young-Tae Chang
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Singapore, 138667, Republic of Singapore.,Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.,Center for Self-assembly and Complexity, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
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31
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Choi KE, Anh VTQ, Kim JT, Yun C, Cha S, Ahn J, Goo YS, Kim SW. An experimental pig model with outer retinal degeneration induced by temporary intravitreal loading of N-methyl-N-nitrosourea during vitrectomy. Sci Rep 2021; 11:258. [PMID: 33420119 PMCID: PMC7794530 DOI: 10.1038/s41598-020-79437-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 12/08/2020] [Indexed: 01/19/2023] Open
Abstract
We aimed to develop an outer retinal degeneration pig model induced by temporary intravitreal loading of N-methyl-N-nitrosourea (MNU) during vitrectomy. In a preliminary experiment involving 5 mini-pig cases to determine the appropriate concentration of MNU, the vitreous cavity of each eye was filled with 4, 8, 10, 12, or 16 mg/mL MNU for 10 min, which was then replaced with a balanced salt solution. Multimodal examinations including spectral-domain optical coherence tomography (OCT) images and full-field electroretinography (ffERG) were obtained at baseline and week 2, week 6, and week 12. The retinal degeneration was classified according to the amplitudes of a dark adaptive (DA) 10.0 a-wave amplitude. The degree of moderate retinal degeneration was defined as DA 10.0 a-wave amplitude ≥ 10% and < 60% of baseline amplitude. The degree of severe degeneration was defined as DA 10.0 a-wave amplitude < 10% of baseline amplitude, noise, or flat signal. Hematoxylin and eosin staining and immunohistochemistry were performed at week 12. The main experiments were conducted first with 10 cases of 5 mg/mL and later with 13 cases of 10 mg/mL. In the preliminary experiment, degree of outer retinal degeneration increased with MNU concentration. Use of 4, 8, 10, 12, and 16 mg/mL MNU showed no, moderate, severe, severe, and atrophic changes, respectively. In the main experiments, there were 9 cases of moderate retinal degeneration and 1 case of severe degeneration in 5 mg/mL MNU group. Two cases of moderate degeneration and 11 of severe degeneration were recorded in 10 mg/mL group. Mean thickness of total retina, inner nuclear layer, and outer nuclear layer decreased at week 2 in both groups. The mean amplitudes on ffERG decreased at week 2. The ffERG and OCT findings did not change from week 2 to week 6 or week 12. The results of staining supported those of ffERG and OCT. Temporal MNU loading in a vitrectomized pig-eye model induced customized outer retinal degeneration with changing the concentration of MNU.
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Affiliation(s)
- Kwang-Eon Choi
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
| | - Vu Thi Que Anh
- Department of Ophthalmology, Hanoi Medical University, Hanoi, Vietnam
| | - Jee Taek Kim
- Department of Ophthalmology, Chung-Ang University College of Medicine, Seoul, South Korea
| | - Cheolmin Yun
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea
| | - Seongkwang Cha
- Department of Physiology, Chungbuk National University College of Medicine, Cheongju, South Korea
| | - Jungryul Ahn
- Department of Physiology, Chungbuk National University College of Medicine, Cheongju, South Korea
| | - Yong Sook Goo
- Department of Physiology, Chungbuk National University College of Medicine, Cheongju, South Korea.
| | - Seong-Woo Kim
- Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea.
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McClements ME, Staurenghi F, MacLaren RE, Cehajic-Kapetanovic J. Optogenetic Gene Therapy for the Degenerate Retina: Recent Advances. Front Neurosci 2020; 14:570909. [PMID: 33262683 PMCID: PMC7686539 DOI: 10.3389/fnins.2020.570909] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 10/23/2020] [Indexed: 12/18/2022] Open
Abstract
The degeneration of light-detecting rod and cone photoreceptors in the human retina leads to severe visual impairment and ultimately legal blindness in millions of people worldwide. Multiple therapeutic options at different stages of degeneration are being explored but the majority of ongoing clinical trials involve adeno-associated viral (AAV) vector-based gene supplementation strategies for select forms of inherited retinal disease. Over 300 genes are associated with inherited retinal degenerations and only a small proportion of these will be suitable for gene replacement therapy. However, while the origins of disease may vary, there are considerable similarities in the physiological changes that occur in the retina. When early therapeutic intervention is not possible and patients suffer loss of photoreceptor cells but maintain remaining layers of cells in the neural retina, there is an opportunity for a universal gene therapy approach that can be applied regardless of the genetic origin of disease. Optogenetic therapy offers such a strategy by aiming to restore vision though the provision of light-sensitive molecules to surviving cell types of the retina that enable light perception through the residual neurons. Here we review the recent progress in attempts to restore visual function to the degenerate retina using optogenetic therapy. We focus on multiple pre-clinical models used in optogenetic strategies, discuss their strengths and limitations, and highlight considerations including vector and transgene designs that have advanced the field into two ongoing clinical trials.
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Affiliation(s)
- Michelle E. McClements
- Nuffield Laboratory Ophthalmology, Department of Clinical Neurosciences, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Federica Staurenghi
- Nuffield Laboratory Ophthalmology, Department of Clinical Neurosciences, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Robert E. MacLaren
- Nuffield Laboratory Ophthalmology, Department of Clinical Neurosciences, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Jasmina Cehajic-Kapetanovic
- Nuffield Laboratory Ophthalmology, Department of Clinical Neurosciences, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
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Gehlen J, Esser S, Schaffrath K, Johnen S, Walter P, Müller F. Blockade of Retinal Oscillations by Benzodiazepines Improves Efficiency of Electrical Stimulation in the Mouse Model of RP, rd10. Invest Ophthalmol Vis Sci 2020; 61:37. [PMID: 33252632 PMCID: PMC7705397 DOI: 10.1167/iovs.61.13.37] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Purpose In RP, photoreceptors degenerate. Retinal prostheses are considered a suitable strategy to restore vision. In animal models of RP, a pathologic rhythmic activity seems to compromise the efficiency of retinal ganglion cell stimulation by an electrical prosthesis. We, therefore, strove to eliminate this pathologic activity. Methods Electrophysiologic recordings of local field potentials and spike activity of retinal ganglion cells were obtained in vitro from retinae of wild-type and rd10 mice using multielectrode arrays. Retinae were stimulated electrically. Results The efficiency of electrical stimulation was lower in rd10 retina than in wild-type retina and this was highly correlated with the presence of oscillations in retinal activity. Glycine and GABA, as well as the benzodiazepines diazepam, lorazepam, and flunitrazepam, abolished retinal oscillations and, most important, increased the efficiency of electrical stimulation to values similar to those in wild-type retina. Conclusions Treatment of patients with these benzodiazepines may offer a way to improve the performance of retinal implants in cases with poor implant proficiency. This study may open the way to a therapy that supports electrical stimulation by prostheses with pharmacologic treatment.
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Affiliation(s)
- Jana Gehlen
- Institute of Biological Information Processing, Molecular and Cellular Physiology, IBI-1, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Stefan Esser
- Institute of Biological Information Processing, Molecular and Cellular Physiology, IBI-1, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Kim Schaffrath
- Department of Ophthalmology, RWTH Aachen University, Aachen, Germany
| | - Sandra Johnen
- Department of Ophthalmology, RWTH Aachen University, Aachen, Germany
| | - Peter Walter
- Department of Ophthalmology, RWTH Aachen University, Aachen, Germany
| | - Frank Müller
- Institute of Biological Information Processing, Molecular and Cellular Physiology, IBI-1, Forschungszentrum Jülich GmbH, Jülich, Germany
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Jolly JK, Menghini M, Johal PA, Buckley TMW, Bridge H, Maclaren RE. Inner retinal thickening affects microperimetry thresholds in the presence of photoreceptor thinning in patients with RPGR retinitis pigmentosa. Br J Ophthalmol 2020; 106:256-261. [PMID: 33127827 DOI: 10.1136/bjophthalmol-2020-317692] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND Loss of photoreceptors cause degeneration in areas of the retina beyond the photoreceptors. The pattern of changes has implications for disease monitoring and measurement of functional changes. The aim of the study was to study the changes in inner retinal structure associated with photoreceptor disease, and the impact of these on microperimetry threshold. METHODS This retrospective cohort study was conducted on optical coherence tomography (OCT) images and microperimetry tests collected between 2013 and 2019. 22 eyes with RPGR retinitis pigmentosa completed both OCT imaging and microperimetry assessment. 18 control eyes underwent OCT imaging. Photoreceptor layer and inner retinal thickness calculated for different eccentric areas were obtained. The relationship between the photoreceptor layer and inner retinal thickness, and microperimetry threshold was explored. RESULTS Central 1° photoreceptor layer and inner retinal thickness were 96±34 and 139±75 μm in RPGR patients, and 139±15 and 62±14 μm in controls. Photoreceptor layer thickness differed between patient and control groups across increasing visual field areas (p<0.01, Kruskal-Wallis 1-way ANOVA), whereas the inner retinal thickness significantly differed between groups for the central 1° and 3° only. Microperimetry thresholds were explained by a combination of photoreceptor thickness (coefficient 0.15, 95% CI 0.13 to 0.18) and inner retinal thickness (coefficient 0.05, 95% CI 0.03 to 0.06). CONCLUSION OCT shows evidence of remodelling in the inner retinal layers secondary to photoreceptor disease. This appears to have an impact on microperimetry threshold measurements.
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Affiliation(s)
- Jasleen Kaur Jolly
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK .,Oxford Centre for Functional MRI of the Brain (FMRIB), Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford OX3 9DU, UK.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Moreno Menghini
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Piers A Johal
- Oxford Centre for Functional MRI of the Brain (FMRIB), Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford OX3 9DU, UK
| | - Thomas M W Buckley
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Holly Bridge
- Oxford Centre for Functional MRI of the Brain (FMRIB), Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford OX3 9DU, UK
| | - Robert E Maclaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
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Lee SE, Lim HB, Shin YI, Ryu CK, Lee WH, Kim JY. Characteristics of the inner retinal layer in the fellow eyes of patients with unilateral exudative age-related macular degeneration. PLoS One 2020; 15:e0239555. [PMID: 32966311 PMCID: PMC7511006 DOI: 10.1371/journal.pone.0239555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 09/08/2020] [Indexed: 11/01/2022] Open
Abstract
OBJECTIVE To investigate the thicknesses of the ganglion cell-inner plexiform layer (GC-IPL) and retinal nerve fiber layer (RNFL) of the fellow eyes of patients with unilateral exudative age-related macular degeneration (AMD). METHODS A total of 107 patients with unilateral exudative AMD [34 of typical choroidal neovascularization (tCNV), Group A; 73 of polypoidal choroidal vasculopathy (PCV), Group B] and 73 normal control eyes (Group C) were included. Drusen and subretinal drusenoid deposits were assessed in all participants using fundus photography, autofluorescence, and optical coherence tomography (OCT). The GC-IPL and RNFL thicknesses were measured using Cirrus HD-OCT and compared among groups. Linear regression analyses were used to evaluate the factors associated with GC-IPL thicknesses. RESULTS The average GC-IPL thicknesses of Groups A, B, and C were 77.09 ± 3.87, 80.10 ± 6.61, and 80.88 ± 6.50 μm, respectively (p = 0.022). Sectoral GC-IPLs and central macular thicknesses (CMTs) were significantly different among groups (all, p <0.05), whereas none of the RNFL parameters differed significantly (all, p >0.05). Multivariate linear regression analyses revealed that age (p <0.001), CMT (p <0.001), and tCNV (p = 0.013) were significantly associated with average GC-IPL thickness, and the rate of reduction of GC-IPL thickness with increasing age in the fellow eyes of tCNV patients was higher than those in the PCV and control groups. CONCLUSIONS Unilateral tCNV patients exhibited statistically significant reduction of the GC-IPL thickness in the fellow eyes, compared to values of the fellow eyes of unilateral PCV patients or control patients. RNFL values trended to be lower but did not reach statistical significance.
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Affiliation(s)
- Seong Eun Lee
- Department of Ophthalmology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
| | - Hyung Bin Lim
- Department of Ophthalmology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
| | - Yong Il Shin
- Department of Ophthalmology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
- Rhee’s Eye Hospital, Daejeon, Republic of Korea
| | - Cheon Kuk Ryu
- Department of Ophthalmology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
| | - Woo Hyuk Lee
- Department of Ophthalmology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
| | - Jung-Yeul Kim
- Department of Ophthalmology, Chungnam National University College of Medicine, Daejeon, Republic of Korea
- * E-mail:
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36
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Pfeiffer RL, Anderson JR, Dahal J, Garcia JC, Yang JH, Sigulinsky CL, Rapp K, Emrich DP, Watt CB, Johnstun HA, Houser AR, Marc RE, Jones BW. A pathoconnectome of early neurodegeneration: Network changes in retinal degeneration. Exp Eye Res 2020; 199:108196. [PMID: 32810483 DOI: 10.1016/j.exer.2020.108196] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/27/2020] [Accepted: 08/11/2020] [Indexed: 10/23/2022]
Abstract
Connectomics has demonstrated that synaptic networks and their topologies are precise and directly correlate with physiology and behavior. The next extension of connectomics is pathoconnectomics: to map neural network synaptology and circuit topologies corrupted by neurological disease in order to identify robust targets for therapeutics. In this report, we characterize a pathoconnectome of early retinal degeneration. This pathoconnectome was generated using serial section transmission electron microscopy to achieve an ultrastructural connectome with 2.18nm/px resolution for accurate identification of all chemical and gap junctional synapses. We observe aberrant connectivity in the rod-network pathway and novel synaptic connections deriving from neurite sprouting. These observations reveal principles of neuron responses to the loss of network components and can be extended to other neurodegenerative diseases.
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Affiliation(s)
- Rebecca L Pfeiffer
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA.
| | - James R Anderson
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA
| | - Jeebika Dahal
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA
| | - Jessica C Garcia
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA
| | - Jia-Hui Yang
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA
| | | | - Kevin Rapp
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA
| | - Daniel P Emrich
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA
| | - Carl B Watt
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA
| | - Hope Ab Johnstun
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA
| | - Alexis R Houser
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA
| | - Robert E Marc
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA; Signature Immunologics, Torrey, UT, USA
| | - Bryan W Jones
- John Moran Eye Center at the University of Utah, Salt Lake City, UT, USA.
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Care RA, Kastner DB, De la Huerta I, Pan S, Khoche A, Della Santina L, Gamlin C, Santo Tomas C, Ngo J, Chen A, Kuo YM, Ou Y, Dunn FA. Partial Cone Loss Triggers Synapse-Specific Remodeling and Spatial Receptive Field Rearrangements in a Mature Retinal Circuit. Cell Rep 2020; 27:2171-2183.e5. [PMID: 31091454 PMCID: PMC6624172 DOI: 10.1016/j.celrep.2019.04.065] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 03/11/2019] [Accepted: 04/12/2019] [Indexed: 11/30/2022] Open
Abstract
Resilience of neural circuits has been observed in the persistence of function despite neuronal loss. In vision, acuity and sensitivity can be retained after 50% loss of cones. While neurons in the cortex can remodel after input loss, the contributions of cell-type-specific circuits to resilience are unknown. Here, we study the effects of partial cone loss in mature mouse retina where cell types and connections are known. At first-order synapses, bipolar cell dendrites remodel and synaptic proteins diminish at sites of input loss. Sites of remaining inputs preserve synaptic proteins. Second-order synapses between bipolar and ganglion cells remain stable. Functionally, ganglion cell spatio-temporal receptive fields retain center-surround structure following partial cone loss. We find evidence for slower temporal filters and expanded receptive field surrounds, derived mainly from inhibitory inputs. Surround expansion is absent in partially stimulated control retina. Results demonstrate functional resilience to input loss beyond pre-existing mechanisms in control retina. Care et al. find that photoreceptor ablation causes structural rearrangement of bipolar cell input synapses while output synapses endure. Functionally, recipient ganglion cells show altered receptive field sizes, an effect not seen after partial stimulation of control retina, demonstrating de novo changes that occur in inhibitory circuitry after photoreceptor loss.
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Affiliation(s)
- Rachel A Care
- Graduate Program in Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA
| | - David B Kastner
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Irina De la Huerta
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Simon Pan
- Graduate Program in Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Atrey Khoche
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Luca Della Santina
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Clare Gamlin
- Program in Neuroscience, Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Chad Santo Tomas
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Jenita Ngo
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Allen Chen
- Department of Neuroscience, University of Rochester, Rochester, NY 14627, USA
| | - Yien-Ming Kuo
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Yvonne Ou
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Felice A Dunn
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94143, USA.
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Palfi A, Yesmambetov A, Humphries P, Hokamp K, Farrar GJ. Non-photoreceptor Expression of Tulp1 May Contribute to Extensive Retinal Degeneration in Tulp1-/- Mice. Front Neurosci 2020; 14:656. [PMID: 32655363 PMCID: PMC7325604 DOI: 10.3389/fnins.2020.00656] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 05/27/2020] [Indexed: 12/24/2022] Open
Abstract
Mutations in tubby like protein 1 gene (TULP1) are causative of early-onset recessive inherited retinal degenerations (IRDs); similarly, the Tulp1-/- mouse is also characterized by a rapid IRD. Tulp1 mRNA and protein expression was analyzed in wild type mouse retinas and expression data sets (NCBI) during early postnatal development. Comparative histology was undertaken in Tulp1-/-, rhodopsin-/- (Rho-/-) and retinal degeneration slow-/- (Rds-/-) mouse retinas. Bioinformatic analysis of predicted TULP1 interactors and IRD genes was performed. Peak expression of Tulp1 in healthy mouse retinas was detected at p8; of note, TULP1 was detected in both the outer and inner retina. Bioinformatic analysis indicated Tulp1 expression in retinal progenitor, photoreceptor and non-photoreceptor cells. While common features of photoreceptor degeneration were detected in Tulp1-/-, Rho-/-, and Rds-/- retinas, other alterations in bipolar, amacrine and ganglion cells were specific to Tulp1-/- mice. Additionally, predicted TULP1 interactors differed in various retinal cell types and new functions for TULP1 were suggested. A pilot bioinformatic analysis indicated that in a similar fashion to Tulp1, many other IRD genes were expressed in both inner and outer retinal cells at p4-p7. Our data indicate that expression of Tulp1 extends to multiple retinal cell types; lack of TULP1 may lead to primary degeneration not only of photoreceptor but also non-photoreceptor cells. Predicted interactors suggest widespread retinal functions for TULP1. Early and widespread expression of TULP1 and some other IRD genes in both the inner and outer retina highlights potential hurdles in the development of treatments for these IRDs.
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Affiliation(s)
- Arpad Palfi
- Department of Genetics, Trinity College Dublin, Dublin, Ireland
| | | | - Pete Humphries
- Department of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Karsten Hokamp
- Department of Genetics, Trinity College Dublin, Dublin, Ireland
| | - G Jane Farrar
- Department of Genetics, Trinity College Dublin, Dublin, Ireland
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Morphologic and electrophysiologic findings of retinal degeneration after intravitreal sodium iodate injection following vitrectomy in canines. Sci Rep 2020; 10:3588. [PMID: 32107442 PMCID: PMC7046695 DOI: 10.1038/s41598-020-60579-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/12/2020] [Indexed: 01/09/2023] Open
Abstract
We developed and characterized a canine model of outer retinal degeneration induced by sodium iodate (SI) intravitreal injection after vitrectomy. In the preliminary study, we repeatedly injected SI intravitreally into the eyes of three canines to develop outer retinal degeneration two weeks after vitrectomy. Based on the preliminary study, a single dose of either 1.2 mg or 1.0 mg SI/0.05 mL was also injected (1.2 mg in n = 5 canines, 1.0 mg in n = 2 canines). Spectral domain-optical coherence tomography (OCT), electroretinography (ERG), and histological examinations were performed at baseline and following intravitreal injection. In the preliminary study, after a 0.5-mg SI injection and a 1.0-mg SI injection and after two 0.8-mg SI injections, retinal degeneration with retinal thinning was observed on OCT imaging. In the second study, after a single 1.0- or 1.2-mg SI injection, outer retinal degeneration was induced. All eyes showed diffuse outer retinal degeneration on OCT and a loss of both cone and rod responses in ERG. Histological examination also showed the loss of outer retinal layer. Intravitreally injected SI (1.0–1.2 mg) in a vitrectomized canine model induced outer retinal degeneration effectively, and could be evaluated through in vivo ophthalmic examination.
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40
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Pfeiffer RL, Marc RE, Jones BW. Persistent remodeling and neurodegeneration in late-stage retinal degeneration. Prog Retin Eye Res 2020; 74:100771. [PMID: 31356876 PMCID: PMC6982593 DOI: 10.1016/j.preteyeres.2019.07.004] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/15/2019] [Accepted: 07/18/2019] [Indexed: 02/06/2023]
Abstract
Retinal remodeling is a progressive series of negative plasticity revisions that arise from retinal degeneration, and are seen in retinitis pigmentosa, age-related macular degeneration and other forms of retinal disease. These processes occur regardless of the precipitating event leading to degeneration. Retinal remodeling then culminates in a late-stage neurodegeneration that is indistinguishable from progressive central nervous system (CNS) proteinopathies. Following long-term deafferentation from photoreceptor cell death in humans, and long-lived animal models of retinal degeneration, most retinal neurons reprogram, then die. Glial cells reprogram into multiple anomalous metabolic phenotypes. At the same time, survivor neurons display degenerative inclusions that appear identical to progressive CNS neurodegenerative disease, and contain aberrant α-synuclein (α-syn) and phosphorylated α-syn. In addition, ultrastructural analysis indicates a novel potential mechanism for misfolded protein transfer that may explain how proteinopathies spread. While neurodegeneration poses a barrier to prospective retinal interventions that target primary photoreceptor loss, understanding the progression and time-course of retinal remodeling will be essential for the establishment of windows of therapeutic intervention and appropriate tuning and design of interventions. Finally, the development of protein aggregates and widespread neurodegeneration in numerous retinal degenerative diseases positions the retina as a ideal platform for the study of proteinopathies, and mechanisms of neurodegeneration that drive devastating CNS diseases.
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Affiliation(s)
- Rebecca L Pfeiffer
- Dept of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, UT, USA; Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA.
| | - Robert E Marc
- Dept of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, UT, USA; Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA
| | - Bryan William Jones
- Dept of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, UT, USA; Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA.
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41
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Stefanov A, Novelli E, Strettoi E. Inner retinal preservation in the photoinducible I307N rhodopsin mutant mouse, a model of autosomal dominant retinitis pigmentosa. J Comp Neurol 2019; 528:1502-1522. [PMID: 31811649 PMCID: PMC7187456 DOI: 10.1002/cne.24838] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 12/03/2019] [Accepted: 12/03/2019] [Indexed: 12/20/2022]
Abstract
Rod‐cone degenerations, for example, retinitis pigmentosa are leading causes of blindness worldwide. Despite slow disease progression in humans, vision loss is inevitable; therefore, development of vision restoration strategies is crucial. Among others, promising approaches include optogenetics and prosthetic implants, which aim to bypass lost photoreceptors (PRs). Naturally, the efficacy of these therapeutic strategies will depend on inner retinal structural and functional preservation. The present study shows that in photoinducible I307N rhodopsin mice (Translational Vision Research Model 4 [Tvrm4]), a 12k lux light exposure eliminates PRs in the central retina in 1 week, but interneurons and their synapses are maintained for as long as 9 weeks postinduction. Despite bipolar cell dendritic retraction and moderate loss of horizontal cells, the survival rate of various cell types is very high. Significant preservation of conventional synapses and gap junctions in the inner plexiform layer is also observed. We found the number of synaptic ribbons to gradually decline and their ultrastructure to become transiently abnormal, although based on our findings intrinsic retinal architecture is maintained despite complete loss of PRs. Unlike common rodent models of PR degeneration, where the disease phenotype often interferes with retinal development, in Tvrm4 mice, the degenerative process can be induced after retinal development is complete. This time course more closely mimics the timing of disease onset in affected patients. Stability of the inner retina found in these mutants 2 months after PR degeneration suggests moderate, stereotyped remodeling in the early stages of the human disease and represents a promising finding for prompt approaches of vision restoration.
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Affiliation(s)
- Antonia Stefanov
- Institute of Neuroscience, Italian National Research Council - CNR, Pisa, Italy.,Regional Doctoral School of Neuroscience, University of Florence, Florence, Italy
| | - Elena Novelli
- Institute of Neuroscience, Italian National Research Council - CNR, Pisa, Italy
| | - Enrica Strettoi
- Institute of Neuroscience, Italian National Research Council - CNR, Pisa, Italy
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An update on retinal prostheses. Clin Neurophysiol 2019; 131:1383-1398. [PMID: 31866339 DOI: 10.1016/j.clinph.2019.11.029] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 11/13/2019] [Accepted: 11/14/2019] [Indexed: 11/23/2022]
Abstract
Retinal prostheses are designed to restore a basic sense of sight to people with profound vision loss. They require a relatively intact posterior visual pathway (optic nerve, lateral geniculate nucleus and visual cortex). Retinal implants are options for people with severe stages of retinal degenerative disease such as retinitis pigmentosa and age-related macular degeneration. There have now been three regulatory-approved retinal prostheses. Over five hundred patients have been implanted globally over the past 15 years. Devices generally provide an improved ability to localize high-contrast objects, navigate, and perform basic orientation tasks. Adverse events have included conjunctival erosion, retinal detachment, loss of light perception, and the need for revision surgery, but are rare. There are also specific device risks, including overstimulation (which could cause damage to the retina) or delamination of implanted components, but these are very unlikely. Current challenges include how to improve visual acuity, enlarge the field-of-view, and reduce a complex visual scene to its most salient components through image processing. This review encompasses the work of over 40 individual research groups who have built devices, developed stimulation strategies, or investigated the basic physiology underpinning retinal prostheses. Current technologies are summarized, along with future challenges that face the field.
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43
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Ahn SM, Ahn J, Cha S, Yun C, Park TK, Kim YJ, Goo YS, Kim SW. The effects of intravitreal sodium iodate injection on retinal degeneration following vitrectomy in rabbits. Sci Rep 2019; 9:15696. [PMID: 31666618 PMCID: PMC6821727 DOI: 10.1038/s41598-019-52172-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/12/2019] [Indexed: 11/17/2022] Open
Abstract
We sought to develop and characterize outer retinal degeneration induced by intravitreal injection of sodium iodate (SI) after vitrectomy in rabbits. To determine the effective dose of SI, the right eyes of 19 male New Zealand white rabbits received an intravitreal injection of SI or sham. Based on the dose-dependence results, 0.4 mg of SI in 0.05 mL of total volume was injected into the right eyes of 10 rabbits at two weeks after vitrectomy. In the dose-dependence study, localized retinal atrophy was observed with 0.3- and 0.4-mg SI injections without vitrectomy. Severe and diffuse retinal atrophy was identified by spectral-domain optical coherence tomography (SD-OCT) at one month after a 0.5-mg SI injection following vitrectomy. In the second experiment, 0.4 mg of SI in 0.05 mL was injected, and the severity of outer retinal degeneration was graded as one of two types according to electroretinography (ERG) response change. There was no response on ERG in complete retinal degeneration, 30% of all 10 rabbits. Intravitreal injection of 0.4 mg of SI into vitrectomized rabbit eyes induces diffuse outer retinal degeneration, and the degree of retinal degeneration can be evaluated through in vivo ophthalmic examination.
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Affiliation(s)
- So Min Ahn
- Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea
| | - Jungryul Ahn
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju, Korea
| | - Seongkwang Cha
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju, Korea
| | - Cheolmin Yun
- Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea
| | - Tae Kwann Park
- Department of Ophthalmology, Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea
| | - Young-Jin Kim
- Medical Device Development Center, Osong Medical Innovation Foundation, Cheongju, Korea
| | - Yong Sook Goo
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju, Korea.
| | - Seong-Woo Kim
- Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea.
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Wu XS, Wang YC, Liu TT, Wang L, Sun XH, Wang LQ, Weng SJ, Zhong YM. Morphological alterations of intrinsically photosensitive retinal ganglion cells after ablation of mouse photoreceptors with selective photocoagulation. Exp Eye Res 2019; 188:107812. [PMID: 31550445 DOI: 10.1016/j.exer.2019.107812] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/06/2019] [Accepted: 09/20/2019] [Indexed: 12/13/2022]
Abstract
In this work, we investigated changes in the morphology of intrinsically photosensitive retinal ganglion cells (ipRGCs), M1 subtype, and pupillary light reflex following local and selective ablation of photoreceptors in mice. Laser photocoagulation was used to selectively destroy four patches of photoreceptors per eye at around 4 papillary diameters from the optic disc and at the 3, 6, 9, and 12 o'clock positions between the retinal vessels in the adult mouse retina, leaving cells in the inner retina intact. Morphological parameters of individual M1 cells specifically labeled by the antibody against melanopsin (PA1-780), including dendritic field size, total dendritic length, and dendritic branch number, were examined 1, 2, 4, and 8 weeks after photocoagulation with Neurolucida software. A considerable reduction in these parameters in M1 cells in the "lesioned areas" was found at all the four time points after photocoagulation, as compared with those in the "unlesioned areas". Although M1 cells in the lesioned areas showed significant changes as early as 1 week after laser treatment and the changes gradually increased, reaching a peak value at 2 weeks, morphological restoration was clearly seen in these cells over time. However, no difference in the morphological parameters of M1 cells was observed between the unlesioned areas of laser-treated mice and the corresponding areas of age-matched normal mice without laser lesions. Fluorescence intensity of the somata of melanopsin-positive M1 cells located inside the lesioned areas was significantly decreased at all the four time points after photocoagulation, whereas no changes in pupillary light reflex were detected at different light irradiations, indicating that photocoagulation-induced local photoreceptor loss and alterations of ipRGCs may be insufficient to cause abnormalities in non-image-forming (NIF) visual functions. The results suggest that intact photoreceptors could be crucial for maintaining the expression levels of melanopsin and normal morphology of M1 cells.
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Affiliation(s)
- Xiao-Sha Wu
- Department of Ophthalmology, State Key Laboratory of Medical Neurobiology and MOE Frontier Center for Brain Science, Institutes of Brain Science and Zhongshan Hospital, Fudan University, Shanghai, 200032, PR China
| | - Yong-Chen Wang
- Department of Ophthalmology, State Key Laboratory of Medical Neurobiology and MOE Frontier Center for Brain Science, Institutes of Brain Science and Zhongshan Hospital, Fudan University, Shanghai, 200032, PR China
| | - Ting-Ting Liu
- Department of Ophthalmology at Eye & ENT Hospital, Fudan University, Shanghai, 200031, PR China
| | - Lu Wang
- Department of Ophthalmology, State Key Laboratory of Medical Neurobiology and MOE Frontier Center for Brain Science, Institutes of Brain Science and Zhongshan Hospital, Fudan University, Shanghai, 200032, PR China
| | - Xing-Huai Sun
- Department of Ophthalmology at Eye & ENT Hospital, Fudan University, Shanghai, 200031, PR China
| | - Li-Qin Wang
- Department of Ophthalmology, State Key Laboratory of Medical Neurobiology and MOE Frontier Center for Brain Science, Institutes of Brain Science and Zhongshan Hospital, Fudan University, Shanghai, 200032, PR China
| | - Shi-Jun Weng
- Department of Ophthalmology, State Key Laboratory of Medical Neurobiology and MOE Frontier Center for Brain Science, Institutes of Brain Science and Zhongshan Hospital, Fudan University, Shanghai, 200032, PR China.
| | - Yong-Mei Zhong
- Department of Ophthalmology, State Key Laboratory of Medical Neurobiology and MOE Frontier Center for Brain Science, Institutes of Brain Science and Zhongshan Hospital, Fudan University, Shanghai, 200032, PR China.
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45
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Falasconi A, Biagioni M, Novelli E, Piano I, Gargini C, Strettoi E. Retinal Phenotype in the rd9 Mutant Mouse, a Model of X-Linked RP. Front Neurosci 2019; 13:991. [PMID: 31607844 PMCID: PMC6761883 DOI: 10.3389/fnins.2019.00991] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 09/03/2019] [Indexed: 12/25/2022] Open
Abstract
Retinal degeneration 9 (rd9) mice carry a mutation in the retina specific “Retinitis Pigmentosa GTPase Regulator (RPGR)” Open Reading Frame (ORF) 15 gene, located on the X chromosome and represent a rare model of X-linked Retinitis Pigmentosa (XLRP), a common and severe form of retinal degeneration (Wright et al., 2010; Tsang and Sharma, 2018). The rd9 RPGR-ORF15 mutation in mice causes lack of the protein in photoreceptors and a slow degeneration of these cells with consequent decrease in Outer Nuclear Layer (ONL) thickness and amplitude of ERG responses, as previously described (Thompson et al., 2012). However, relative rates of rod and cone photoreceptor loss, as well as secondary alterations occurring in neuronal and non-neuronal retinal cell types of rd9 mutants remain to be assessed. Aim of this study is to extend phenotype analysis of the rd9 mouse retina focusing on changes occurring in cells directly interacting with photoreceptors. To this purpose, first we estimated rod and cone survival and its degree of intraretinal variation over time; then, we studied the morphology of horizontal and bipolar cells and of the retinal pigment epithelium (RPE), extending our observations to glial cell reactivity. We found that in rd9 retinas rod (but not cone) death is the main cause of decrease in ONL thickness and that degeneration shows a high degree of intraretinal variation. Rod loss drives remodeling in the outer retina, with sprouting of second-order neurons of the rod-pathway and relative sparing of cone pathway elements. Remarkably, despite cone survival, functional defects can be clearly detected in ERG recordings in both scotopic and photopic conditions. Moderate levels of Muller cells and microglial reactivity are sided by striking attenuation of staining for RPE tight junctions, suggesting altered integrity of the outer Blood Retina Barrier (BRB). Because of many features resembling slowly progressing photoreceptor degeneration paradigms or early stages of more aggressive forms of RP, the rd9 mouse model can be considered a rare and useful tool to investigate retinal changes associated to a process of photoreceptor death sustained throughout life and to reveal disease biomarkers (e.g., BRB alterations) of human XLRP.
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Affiliation(s)
- Antonio Falasconi
- Institute of Neuroscience, National Research Council (CNR), Pisa, Italy.,Sant'Anna School of Advanced Studies, Pisa, Italy
| | - Martina Biagioni
- Institute of Neuroscience, National Research Council (CNR), Pisa, Italy
| | - Elena Novelli
- Institute of Neuroscience, National Research Council (CNR), Pisa, Italy
| | - Ilaria Piano
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | | | - Enrica Strettoi
- Institute of Neuroscience, National Research Council (CNR), Pisa, Italy
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Procyk CA, Allen AE, Martial FP, Lucas RJ. Visual responses in the dorsal lateral geniculate nucleus at early stages of retinal degeneration in rd1 PDE6β mice. J Neurophysiol 2019; 122:1753-1764. [PMID: 31461375 DOI: 10.1152/jn.00231.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Inherited retinal degenerations encompass a wide range of diseases that result in the death of rod and cone photoreceptors, eventually leading to irreversible blindness. Low vision survives at early stages of degeneration, at which point it could rely on residual populations of rod/cone photoreceptors as well as the inner retinal photoreceptor, melanopsin. To date, the impact of partial retinal degeneration on visual responses in the primary visual thalamus (dorsal lateral geniculate nucleus, dLGN) remains unknown, as does their relative reliance on surviving rod and cone photoreceptors vs. melanopsin. To answer these questions, we recorded visually evoked responses in the dLGN of anesthetized rd1 mice using in vivo electrophysiology at an age (3-5 wk) at which cones are partially degenerate and rods are absent. We found that excitatory (ON) responses to light had lower amplitude and longer latency in rd1 mice compared with age-matched visually intact controls; however, contrast sensitivity and spatial receptive field size were largely unaffected at this early stage of degeneration. Responses were retained when those wavelengths to which melanopsin is most sensitive were depleted, indicating that they were driven primarily by surviving cones. Inhibitory responses appeared absent in the rd1 thalamus, as did light-evoked gamma oscillations in firing. This description of fundamental features of the dLGN visual response at this intermediate stage of retinal degeneration provides a context for emerging attempts to restore vision by introducing ectopic photoreception to the degenerate retina.NEW & NOTEWORTHY This study provides new therapeutically relevant insights to visual responses in the dorsal lateral geniculate nucleus during progressive retinal degeneration. Using in vivo electrophysiology, we demonstrate that visual responses have lower amplitude and longer latency during degeneration, but contrast sensitivity and spatial receptive fields remain unaffected. Such visual responses are driven predominantly by surviving cones rather than melanopsin photoreceptors. The functional integrity of this visual pathway is encouraging for emerging attempts at visual restoration.
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Affiliation(s)
- Christopher A Procyk
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Annette E Allen
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Franck P Martial
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Robert J Lucas
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
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Affiliation(s)
- Chen Xing Zhang
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, People's Republic of China
| | - Zheng Qin Yin
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, People's Republic of China
| | - Li-Feng Chen
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, People's Republic of China
| | - Chuang-Huang Weng
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, People's Republic of China
| | - Yu-Xiao Zeng
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, People's Republic of China
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48
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Ueno S, Kominami T, Okado S, Inooka D, Kondo M, Terasaki H. Course of loss of photoreceptor function and progressive Müller cell gliosis in rhodopsin P347L transgenic rabbits. Exp Eye Res 2019; 184:192-200. [PMID: 31029790 DOI: 10.1016/j.exer.2019.04.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 04/17/2019] [Accepted: 04/24/2019] [Indexed: 01/31/2023]
Abstract
Long living animal models of retinitis pigmentosa (RP) can provide important information on the retinal changes that occur at the late stages of photoreceptor degeneration. The rhodopsin Pro347Leu transgenic rabbit (P347L Tg) is a model of RP, and it has been used to analyze the functional and morphological changes in the retina following the degeneration of the photoreceptors. They have also been used to test newly-developed therapies to treat eyes with photoreceptor degeneration. However, assessments of the retinal changes in P347L Tg rabbits older than 1-year have not been reported even though the data are important for research on developing new therapies to restore vision at the end stages of RP. The purpose of this study was to determine the time course of the loss of photoreceptor function and the changes in the morphology of the retina of P347L Tg rabbits. The experiments were performed on 26 older P347L Tg rabbits. The results showed that the amplitudes of the ERGs of the P347L Tg rabbits gradually decreased and reached <10 μV between 30- and 54-months-of-age. Histological analysis at these later stages showed a loss of the photoreceptor layer, and OCT analysis showed absence of the layering of the retina. However, the thickness between the inner limiting membrane and the outer plexiform layer was about 1.7 times thicker than the corresponding thickness of WT rabbits in the OCT images. This thickening was caused by a marked gliosis of the entire retina which was confirmed by light and transmission electron microscopy. In addition, immunohistochemical analysis showed there was excessive staining of the glial fibrillary acid protein in the older P347L Tg rabbits although the rod ON bipolar cells and horizontal cells were still present in the inner nuclear layer. Our results indicate that the P347L Tg rabbit progressed to complete photoreceptor loss within 30- and 54-months-of-age and severe gliosis altered the morphology of the retina.
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Affiliation(s)
- Shinji Ueno
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
| | - Taro Kominami
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Satoshi Okado
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Daiki Inooka
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Mineo Kondo
- Department of Ophthalmology, Mie University Graduate School of Medicine, Tsu, Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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49
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Lebon C, Behar-Cohen F, Torriglia A. Cell Death Mechanisms in a Mouse Model of Retinal Degeneration in Spinocerebellar Ataxia 7. Neuroscience 2019; 400:72-84. [PMID: 30625334 DOI: 10.1016/j.neuroscience.2018.12.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 12/30/2018] [Accepted: 12/31/2018] [Indexed: 10/27/2022]
Abstract
Spino-cerebellar ataxia type 7 (SCA7) is a polyglutamine (polyQ) disorder characterized by neurodegeneration of the brain, cerebellum, and retina caused by a polyglutamine expansion in ataxin7. The presence of an expanded polyQ tract in a mutant protein is known to induce protein aggregation, cellular stress, toxicity, and finally cell death. However, the consequences of the presence of mutant ataxin7 in the retina and the mechanisms underlying photoreceptor degeneration remain poorly understood. In this study, we show that in a retinal SCA7 mouse model, polyQ ataxin7 induces stress within the retina and activates Muller cells. Moreover, unfolded protein response and autophagy are activated in SCA7 photoreceptors. We have also shown that the photoreceptor death does not involve a caspase-dependent apoptosis but instead involves apoptosis inducing factor (AIF) and Leukocyte Elastase Inhibitor (LEI/L-DNase II). When these two cell death effectors are downregulated by their siRNA, a significant reduction in photoreceptor death is observed. These results highlight the consequences of polyQ protein expression in the retina and the role of caspase-independent pathways involved in photoreceptor cell death.
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Affiliation(s)
- Cecile Lebon
- Inserm U1138. Centre des Recherches des Cordeliers, 15, rue de l'Ecole de Médecine, 78006 Paris, France; Université Pierre et Marie Curie, France; Université Paris Descartes, France
| | - Francine Behar-Cohen
- Inserm U1138. Centre des Recherches des Cordeliers, 15, rue de l'Ecole de Médecine, 78006 Paris, France; Université Pierre et Marie Curie, France; Université Paris Descartes, France
| | - Alicia Torriglia
- Inserm U1138. Centre des Recherches des Cordeliers, 15, rue de l'Ecole de Médecine, 78006 Paris, France; Université Pierre et Marie Curie, France; Université Paris Descartes, France.
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50
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Pangrsic T, Singer JH, Koschak A. Voltage-Gated Calcium Channels: Key Players in Sensory Coding in the Retina and the Inner Ear. Physiol Rev 2019; 98:2063-2096. [PMID: 30067155 DOI: 10.1152/physrev.00030.2017] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Calcium influx through voltage-gated Ca (CaV) channels is the first step in synaptic transmission. This review concerns CaV channels at ribbon synapses in primary sense organs and their specialization for efficient coding of stimuli in the physical environment. Specifically, we describe molecular, biochemical, and biophysical properties of the CaV channels in sensory receptor cells of the retina, cochlea, and vestibular apparatus, and we consider how such properties might change over the course of development and contribute to synaptic plasticity. We pay particular attention to factors affecting the spatial arrangement of CaV channels at presynaptic, ribbon-type active zones, because the spatial relationship between CaV channels and release sites has been shown to affect synapse function critically in a number of systems. Finally, we review identified synaptopathies affecting sensory systems and arising from dysfunction of L-type, CaV1.3, and CaV1.4 channels or their protein modulatory elements.
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Affiliation(s)
- Tina Pangrsic
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
| | - Joshua H Singer
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
| | - Alexandra Koschak
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
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