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Lee PY, Bui BV. Age-related differences in retinal function and structure in C57BL/6J and Thy1-YFPh mice. Neurobiol Aging 2024; 141:171-181. [PMID: 38964014 DOI: 10.1016/j.neurobiolaging.2024.06.005] [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: 11/30/2023] [Revised: 06/18/2024] [Accepted: 06/19/2024] [Indexed: 07/06/2024]
Abstract
Age-related neuronal adaptations are known to help maintain function. This study aims to examine gross age-related in vivo retinal functional adaptations (using electroretinography) in young and middle aged C57BL/6J and Thy1-YFPh mice and to relate this to in vivo retinal structure (using optical coherence tomography). Electroretinography responses were generally larger in Thy1-YFPh mice than in C57BL/6J mice, with similar in vivo retinal layer thicknesses except for longer inner/outer photoreceptor segment in Thy1-YFPh mice. Relative to 3-month-old mice, 12-month-old mice showed reduced photoreceptor (C57BL/6J 84.0±2.5 %; Thy1-YFPh 80.2±5.2 %) and bipolar cell (C57BL/6J 75.6±2.3 %; Thy1-YFPh 68.1±5.5 %) function. There was relative preservation of ganglion cell function (C57BL/6J 79.7±3.7 %; Thy1-YFPh 91.7±5.0 %) with age, which was associated with increased b-wave (bipolar cell) sensitivities to light. Ganglion cell function was correlated with both b-wave amplitude and sensitivity. This study shows that there are normal age-related adaptations to preserve functional output. Different mouse strains may have varied age-related adaptation capacity and should be taken into consideration when examining age-related susceptibility to injury.
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Affiliation(s)
- Pei Ying Lee
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, Australia.
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2
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Chauhan P, Kho AM, Srinivasan VJ. From Soma to Synapse: Imaging Age-Related Rod Photoreceptor Changes in the Mouse with Visible Light OCT. OPHTHALMOLOGY SCIENCE 2023; 3:100321. [PMID: 37388138 PMCID: PMC10302163 DOI: 10.1016/j.xops.2023.100321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 04/05/2023] [Accepted: 04/24/2023] [Indexed: 07/01/2023]
Abstract
Purpose Although the outer nuclear layer (ONL) and outer plexiform layer (OPL) each exhibit a complex internal organization, near-infrared OCT depicts both as monolithic bands. Here, using visible light OCT in the C57BL/6J mouse retina, sublaminar age-related changes in photoreceptor features were imaged and interpreted. These features were (1) oscillations in reflectivity, or striations, in the ONL and (2) a moderately reflective subband in the OPL. Design Cross-sectional study. Participants Pigmented mice (C57BL/6J, n = 14). Methods A 1.0-μm axial resolution visible light spectral/Fourier domain OCT system was used for in vivo retinal imaging. Light and electron microscopy were performed ex vivo. Linear mixed effects models or regression were employed for statistical analysis. Main Outcome Measures Comparison of OCT subbands with corresponding histological features, as well as quantification of subband thickness and reflectivity. Results Corresponding histological comparisons confirm that striations in the ONL arise from the rowlike arrangement of photoreceptor nuclei and reveal that the moderately reflective OPL subband arises from rod spherules. Compression of outer ONL striations with age suggests changes in soma organization. Thinning of the moderately reflective OPL subband with age supports a reduction of synapses in the OPL. Critically, the ONL somas are tightly correlated with the purported spherule layer but not with the rest of the OPL. Conclusions Visible light OCT imaging of the mouse OPL resolves postsynaptic and synaptic differences. Visible light OCT can study rod photoreceptor changes from the soma to the synapse in the living mouse retina. Financial Disclosures Proprietary or commercial disclosure may be found after the references.
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Affiliation(s)
- Pooja Chauhan
- Department of Radiology, NYU Langone Health, New York, New York
| | - Aaron M. Kho
- Department of Biomedical Engineering, University of California Davis, Davis, California
| | - Vivek J. Srinivasan
- Department of Radiology, NYU Langone Health, New York, New York
- Department of Biomedical Engineering, University of California Davis, Davis, California
- Department of Ophthalmology, NYU Langone Health, New York, New York
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3
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Goodman C, Podolsky RH, Childers KL, Roberts R, Katz R, Waseem R, Paruchuri A, Stanek J, Berkowitz BA. Do multiple physiological OCT biomarkers indicate age-related decline in rod mitochondrial function in C57BL/6J mice? Front Neurosci 2023; 17:1280453. [PMID: 38046657 PMCID: PMC10693340 DOI: 10.3389/fnins.2023.1280453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 10/31/2023] [Indexed: 12/05/2023] Open
Abstract
Purpose To test the hypothesis that rod photoreceptor mitochondria function in vivo progressively declines over time. Methods 2, 12, and 24 month-old dark- and light-adapted C57BL/6J (B6J) mice were examined by OCT. We measured (i) an index of mitochondrial configuration within photoreceptors measured from the profile shape aspect ratio (MCP/AR) of the hyperreflective band posterior to the external limiting membrane (ELM), (ii) a proxy for energy-dependent pH-triggered water removal, the thickness of the ELM-retinal pigment epithelium (ELM-RPE), and its correlate (iii) the hyporeflective band (HB) signal intensity at the photoreceptor tips. Visual performance was assessed by optokinetic tracking. Results In 2 and 24 month-old mice, MCP/AR in both inferior and superior retina was smaller in light than in dark; no dark-light differences were noted in 12 month-old mice. Dark-adapted inferior and superior, and light-adapted superior, ELM-RPE thickness increased with age. The dark-light difference in ELM-RPE thickness remained constant across all ages. All ages showed a decreased HB signal intensity magnitude in dark relative to light. In 12 month-old mice, the dark-light difference in HB magnitude was greater than in younger and older mice. Anatomically, outer nuclear layer thickness decreased with age. Visual performance indices were reduced at 24 month-old compared to 2 month-old mice. Conclusion While the working hypothesis was not supported herein, the results raise the possibility of a mid-life adaptation in rod mitochondrial function during healthy aging in B6J mice based on OCT biomarkers, a plasticity that occurred prior to declines in visual performance.
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Affiliation(s)
- Cole Goodman
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Robert H. Podolsky
- Biostatistics and Study Methodology, Children’s National Hospital, Silver Spring, MD, United States
| | | | - Robin Roberts
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Ryan Katz
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Rida Waseem
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Anuhya Paruchuri
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Josh Stanek
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Bruce A. Berkowitz
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI, United States
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Gierke K, Lux UT, Regus-Leidig H, Brandstätter JH. The first synapse in vision in the aging mouse retina. Front Cell Neurosci 2023; 17:1291054. [PMID: 38026697 PMCID: PMC10654782 DOI: 10.3389/fncel.2023.1291054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
Vision is our primary sense, and maintaining it throughout our lifespan is crucial for our well-being. However, the retina, which initiates vision, suffers from an age-related, irreversible functional decline. What causes this functional decline, and how it might be treated, is still unclear. Synapses are the functional hub for signal transmission between neurons, and studies have shown that aging is widely associated with synaptic dysfunction. In this study, we examined the first synapse of the visual system - the rod and cone photoreceptor ribbon synapse - in the mouse retina using light and electron microscopy at 2-3 months, ~1 year, and >2 years of age. We asked, whether age-related changes in key synaptic components might be a driver of synaptic dysfunction and ultimately age-related functional decline during normal aging. We found sprouting of horizontal and bipolar cells, formation of ectopic photoreceptor ribbon synapses, and a decrease in the number of rod photoreceptors and photoreceptor ribbon synapses in the aged retina. However, the majority of the photoreceptors did not show obvious changes in the structural components and protein composition of their ribbon synapses. Noteworthy is the increase in mitochondrial size in rod photoreceptor terminals in the aged retina.
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Affiliation(s)
| | | | | | - Johann Helmut Brandstätter
- Animal Physiology/Neurobiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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Clemons MR, Dimico RH, Black C, Schlussler MK, Camerino MJ, Aldinger-Gibson K, Bartle A, Reynolds N, Eisenbrandt D, Rogers A, Andrianu J, Bruce B, Elliot A, Breazeal T, Griffin H, Murphy MK, Fuerst PG. The rod synapse in aging wildtype and Dscaml1 mutant mice. PLoS One 2023; 18:e0290257. [PMID: 37910517 PMCID: PMC10619811 DOI: 10.1371/journal.pone.0290257] [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: 02/08/2023] [Accepted: 08/03/2023] [Indexed: 11/03/2023] Open
Abstract
The retina is an intricately organized neural tissue built on cone and rod pathways for color and night vision. Genetic mutations that disrupt the proper function of the rod circuit contribute to blinding diseases including retinitis pigmentosa and congenital stationary night blindness (CSNB). Down Syndrome cell adhesion molecule like 1 (Dscaml1) is expressed by rods, rod bipolar cells (RBCs), and sub-populations of amacrine cells, and has been linked to a middle age onset of CSNB in humans. However, how Dscaml1 contributes to this visual deficit remains unexplored. Here, we probed Dscaml1's role in the maintenance of the rod-to-RBC synapse using a loss of function mouse model. We used immunohistochemistry to investigate the anatomical formation and maintenance of the rod-to-RBC synapse in the young, adult, and aging retina. We generated 3D reconstructions, using serial electron micrographs, of rod spherules and RBCs to measure the number of invaginating neurites, RBC dendritic tip number, and RBC mitochondrial morphology. We find that while rod-to-RBC synapses form and are maintained, similar to wildtype, that there is an increase in the number of invaginating neurites in rod spherules, a reduction in RBC dendritic tips, and reduced mitochondrial volume and complexity in the Dscaml1 mutant retina compared to controls. We also observed precocious sprouting of RBC dendrites into the outer nuclear layer (ONL) of the Dscaml1 mutant retina compared to controls. These results contribute to our knowledge of Dscaml1's role in rod circuit development and maintenance and give additional insight into possible genetic therapy targets for blinding diseases and disorders like CSNB.
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Affiliation(s)
- Mellisa R. Clemons
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Natural Sciences, North Idaho College, Coeur d’Alene, Idaho, United States of America
| | - Ren H. Dimico
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Cailyn Black
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Megan K. Schlussler
- Natural Sciences, North Idaho College, Coeur d’Alene, Idaho, United States of America
| | - Michael J. Camerino
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Kirah Aldinger-Gibson
- Natural Sciences, North Idaho College, Coeur d’Alene, Idaho, United States of America
| | - Amaris Bartle
- Natural Sciences, North Idaho College, Coeur d’Alene, Idaho, United States of America
| | - Nathan Reynolds
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Natural Sciences, North Idaho College, Coeur d’Alene, Idaho, United States of America
| | - Dylan Eisenbrandt
- Natural Sciences, North Idaho College, Coeur d’Alene, Idaho, United States of America
| | - Aspen Rogers
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - John Andrianu
- Natural Sciences, North Idaho College, Coeur d’Alene, Idaho, United States of America
| | - Bradley Bruce
- WWAMI Medical Education Program, University of Washington School of Medicine, Moscow, Idaho, United States of America
| | - Arthur Elliot
- Natural Sciences, North Idaho College, Coeur d’Alene, Idaho, United States of America
| | - Tom Breazeal
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Hannah Griffin
- Natural Sciences, North Idaho College, Coeur d’Alene, Idaho, United States of America
| | - Molly K. Murphy
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Natural Sciences, North Idaho College, Coeur d’Alene, Idaho, United States of America
| | - Peter G. Fuerst
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- WWAMI Medical Education Program, University of Washington School of Medicine, Moscow, Idaho, United States of America
- Department of Biochemistry, Wake Forest School of Medicine, Winston Salem, North Carolina, United States of America
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6
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Shrestha AP, Rameshkumar N, Boff JM, Rajmanna R, Chandrasegaran T, Frederick CE, Zenisek D, Vaithianathan T. The Effects of Aging on Rod Bipolar Cell Ribbon Synapses. Cells 2023; 12:2385. [PMID: 37830599 PMCID: PMC10572008 DOI: 10.3390/cells12192385] [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: 08/20/2023] [Revised: 09/20/2023] [Accepted: 09/27/2023] [Indexed: 10/14/2023] Open
Abstract
The global health concern posed by age-related visual impairment highlights the need for further research focused on the visual changes that occur during the process of aging. To date, multiple sensory alterations related to aging have been identified, including morphological and functional changes in inner hair cochlear cells, photoreceptors, and retinal ganglion cells. While some age-related morphological changes are known to occur in rod bipolar cells in the retina, their effects on these cells and on their connection to other cells via ribbon synapses remain elusive. To investigate the effects of aging on rod bipolar cells and their ribbon synapses, we compared synaptic calcium currents, calcium dynamics, and exocytosis in zebrafish (Danio rerio) that were middle-aged (MA,18 months) or old-aged (OA, 36 months). The bipolar cell terminal in OA zebrafish exhibited a two-fold reduction in number of synaptic ribbons, an increased ribbon length, and a decrease in local Ca2+ signals at the tested ribbon location, with little change in the overall magnitude of the calcium current or exocytosis in response to brief pulses. Staining of the synaptic ribbons with antibodies specific for PKCa revealed shortening of the inner nuclear and plexiform layers (INL and IPL). These findings shed light on age-related changes in the retina that are related to synaptic ribbons and calcium signals.
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Affiliation(s)
- Abhishek P. Shrestha
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Nirujan Rameshkumar
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Johane M. Boff
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Rhea Rajmanna
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | | | - Courtney E. Frederick
- Department of Molecular and Cellular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA (D.Z.)
| | - David Zenisek
- Department of Molecular and Cellular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA (D.Z.)
| | - Thirumalini Vaithianathan
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Department of Ophthalmology, Hamilton Eye Institute, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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7
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Abstract
Because the central nervous system is largely nonrenewing, neurons and their synapses must be maintained over the lifetime of an individual to ensure circuit function. Age is a dominant risk factor for neural diseases, and declines in nervous system function are a common feature of aging even in the absence of disease. These alterations extend to the visual system and, in particular, to the retina. The retina is a site of clinically relevant age-related alterations but has also proven to be a uniquely approachable system for discovering principles that govern neural aging because it is well mapped, contains diverse neuron types, and is experimentally accessible. In this article, we review the structural and molecular impacts of aging on neurons within the inner and outer retina circuits. We further discuss the contribution of non-neuronal cell types and systems to retinal aging outcomes. Understanding how and why the retina ages is critical to efforts aimed at preventing age-related neural decline and restoring neural function.
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Affiliation(s)
- Jeffrey D Zhu
- Department of Neuroscience, Huffington Center on Aging, Baylor College of Medicine, Houston, Texas, USA;
| | - Sharma Pooja Tarachand
- Department of Neuroscience, Huffington Center on Aging, Baylor College of Medicine, Houston, Texas, USA;
| | - Qudrat Abdulwahab
- Department of Neuroscience, Huffington Center on Aging, Baylor College of Medicine, Houston, Texas, USA;
| | - Melanie A Samuel
- Department of Neuroscience, Huffington Center on Aging, Baylor College of Medicine, Houston, Texas, USA;
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8
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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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9
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Perez-Hurtado M, Dao C, Saenz AE, Heidelberger R. Syntaxin 3 is haplosufficient for long-term photoreceptor survival in the mouse retina. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1208805. [PMID: 37609371 PMCID: PMC10443939 DOI: 10.3389/fopht.2023.1208805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Biallelic loss-of-function mutations in the syntaxin 3 gene have been linked to a severe retinal dystrophy in humans that presents in early childhood. In mouse models, biallelic inactivation of the syntaxin 3 gene in photoreceptors rapidly leads to their death. What is not known is whether a monoallelic syntaxin 3 loss-of-function mutation might cause photoreceptor loss with advancing age. To address this question, we compared the outer nuclear layer of older adult mice (≈ 20 months of age) that were heterozygous for syntaxin 3 with those of similarly-aged control mice. We found that the photoreceptor layer maintains its thickness in mice that are heterozygous for syntaxin 3 relative to controls and that photoreceptor somatic counts are comparable. In addition, dendritic sprouting of the rod bipolar cell dendrites into the outer nuclear layer, which occurs following the loss of functional rod targets, was similar between genotypes. Thus, syntaxin 3 appears to be haplosufficient for photoreceptor survival, even with advancing age.
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Affiliation(s)
- Mariajose Perez-Hurtado
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX
| | - Calvin Dao
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX
| | - Amanda E. Saenz
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX
| | - Ruth Heidelberger
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston (UTHealth Houston), Houston, TX
- The University of Texas MDAnderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston TX
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10
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Kovács-Valasek A, Rák T, Pöstyéni E, Csutak A, Gábriel R. Three Major Causes of Metabolic Retinal Degenerations and Three Ways to Avoid Them. Int J Mol Sci 2023; 24:ijms24108728. [PMID: 37240082 DOI: 10.3390/ijms24108728] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
An imbalance of homeostasis in the retina leads to neuron loss and this eventually results in a deterioration of vision. If the stress threshold is exceeded, different protective/survival mechanisms are activated. Numerous key molecular actors contribute to prevalent metabolically induced retinal diseases-the three major challenges are age-related alterations, diabetic retinopathy and glaucoma. These diseases have complex dysregulation of glucose-, lipid-, amino acid or purine metabolism. In this review, we summarize current knowledge on possible ways of preventing or circumventing retinal degeneration by available methods. We intend to provide a unified background, common prevention and treatment rationale for these disorders and identify the mechanisms through which these actions protect the retina. We suggest a role for herbal medicines, internal neuroprotective substances and synthetic drugs targeting four processes: parainflammation and/or glial cell activation, ischemia and related reactive oxygen species and vascular endothelial growth factor accumulation, apoptosis and/or autophagy of nerve cells and an elevation of ocular perfusion pressure and/or intraocular pressure. We conclude that in order to achieve substantial preventive or therapeutic effects, at least two of the mentioned pathways should be targeted synergistically. A repositioning of some drugs is considered to use them for the cure of the other related conditions.
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Affiliation(s)
- Andrea Kovács-Valasek
- Department of Experimental Zoology and Neurobiology, University of Pécs, Ifjúság útja 6, 7624 Pécs, Hungary
| | - Tibor Rák
- Department of Ophthalmology, Medical School, University of Pécs, Szigeti út 12, 7624 Pécs, Hungary
| | - Etelka Pöstyéni
- Department of Experimental Zoology and Neurobiology, University of Pécs, Ifjúság útja 6, 7624 Pécs, Hungary
| | - Adrienne Csutak
- Department of Ophthalmology, Medical School, University of Pécs, Szigeti út 12, 7624 Pécs, Hungary
| | - Robert Gábriel
- Department of Experimental Zoology and Neurobiology, University of Pécs, Ifjúság útja 6, 7624 Pécs, Hungary
- János Szentágothai Research Centre, University of Pécs, Ifjúság útja 20, 7624 Pécs, Hungary
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Ardourel M, Ranchon-Cole I, Pâris A, Felgerolle C, Acar N, Lesne F, Briault S, Perche O. FMR protein: Evidence of an emerging role in retinal aging? Exp Eye Res 2022; 225:109282. [PMID: 36265576 DOI: 10.1016/j.exer.2022.109282] [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: 08/11/2022] [Revised: 10/05/2022] [Accepted: 10/11/2022] [Indexed: 12/29/2022]
Abstract
Aging is a multifactorial process that affects the entire organism by cumulative alterations. Visual function impairments that go along with aging are commonly observed, causing lower visual acuity, lower contrast sensitivity, and impaired dark adaptation. Electroretinogram analysis revealed that the amplitudes of rod- and cone-mediated responses are reduced in aged mice and humans. Reports suggested that age-related changes observed in both rod and cone photoreceptor functionality were linked to oxidative stress regulation or free radical production homeostasis. Interestingly, several recent reports linked the fragile X mental retardation protein (FMRP) cellular activity with oxidative stress regulation in several tissue including brain tissue where FMRP participates to the response to stress via protein translation in neurite or is involved in free radical production and abnormal glutathione homeostasis. Based on these recent literatures, we raised the question about the effect of FMRP absence in the aging retina of Fmr1-/y compared to their WT littermates. Indeed, up to now, only young or adult mice (<6 months) were investigated and have shown a specific retinal phenotype. Herein, we demonstrated that Fmr1-/y mice do not present the aging effect on retinal function observed in WT littermates since ERG a- and b-waves amplitudes as well as oscillatory potentials amplitudes were not collapsed with age (12/18 months old). Absence of FMRP and its consequences seem to protect the retina against aging effect, rising a pivotal role of FMRP in retinal aging process.
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Affiliation(s)
- M Ardourel
- UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, 45071, Orléans, Cedex 2, France
| | - I Ranchon-Cole
- Université Clermont Auvergne, CHU Clermont-Ferrand, Inserm, Neuro-Dol, F-63000, Clermont-Ferrand, France
| | - A Pâris
- UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, 45071, Orléans, Cedex 2, France
| | - C Felgerolle
- UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, 45071, Orléans, Cedex 2, France
| | - N Acar
- Eye and Nutrition Research Group, Centre des Sciences du Goût et de l'Alimentation, CNRS, INRAE, Institut Agro, Université Bourgogne Franche-Comté, 21000, Dijon, France
| | - F Lesne
- Genetic Department, Regional Hospital, 14 Avenue de l'hôpital, 45100, Orléans, France
| | - S Briault
- UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, 45071, Orléans, Cedex 2, France; Genetic Department, Regional Hospital, 14 Avenue de l'hôpital, 45100, Orléans, France
| | - O Perche
- UMR7355, CNRS, Orléans, France; Experimental and Molecular Immunology and Neurogenetics, University of Orléans, 3b rue de la Ferollerie, 45071, Orléans, Cedex 2, France; Genetic Department, Regional Hospital, 14 Avenue de l'hôpital, 45100, Orléans, France.
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12
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Blasiak J, Sobczuk P, Pawlowska E, Kaarniranta K. Interplay between aging and other factors of the pathogenesis of age-related macular degeneration. Ageing Res Rev 2022; 81:101735. [PMID: 36113764 DOI: 10.1016/j.arr.2022.101735] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/03/2022] [Accepted: 09/12/2022] [Indexed: 01/31/2023]
Abstract
Age-related macular degeneration (AMD) is a complex eye disease with the retina as the target tissue and aging as per definition the most serious risk factor. However, the retina contains over 60 kinds of cells that form different structures, including the neuroretina and retinal pigment epithelium (RPE) which can age at different rates. Other established or putative AMD risk factors can differentially affect the neuroretina and RPE and can differently interplay with aging of these structures. The occurrence of β-amyloid plaques and increased levels of cholesterol in AMD retinas suggest that AMD may be a syndrome of accelerated brain aging. Therefore, the question about the real meaning of age in AMD is justified. In this review we present and update information on how aging may interplay with some aspects of AMD pathogenesis, such as oxidative stress, amyloid beta formation, circadian rhythm, metabolic aging and cellular senescence. Also, we show how this interplay can be specific for photoreceptors, microglia cells and RPE cells as well as in Bruch's membrane and the choroid. Therefore, the process of aging may differentially affect different retinal structures. As an accurate quantification of biological aging is important for risk stratification and early intervention for age-related diseases, the determination how photoreceptors, microglial and RPE cells age in AMD may be helpful for a precise diagnosis and treatment of this largely untreatable disease.
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Affiliation(s)
- Janusz Blasiak
- Department of Molecular Genetics, University of Lodz, Pomorska 141/143, 90-236, Lodz, Poland.
| | - Piotr Sobczuk
- Emergency Medicine and Disaster Medicine Department, Medical University of Lodz, Pomorska 251, 92-209 Lodz, Poland; Department of Orthopaedics and Traumatology, Polish Mothers' Memorial Hospital - Research Institute, Rzgowska 281, 93-338 Lodz, Poland
| | - Elzbieta Pawlowska
- Department of Pediatric Dentistry, Medical University of Lodz, Pomorska 251, 92-216 Lodz, Poland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, KYS, P.O. Box 100, FI-70029 Finland
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13
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Haverkamp S, Reinhard K, Peichl L, Mietsch M. No evidence for age-related alterations in the marmoset retina. Front Neuroanat 2022; 16:945295. [PMID: 36120100 PMCID: PMC9479465 DOI: 10.3389/fnana.2022.945295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 07/13/2022] [Indexed: 12/19/2022] Open
Abstract
The physiological aging process of the retina is accompanied by various and sometimes extensive changes: Macular degeneration, retinopathies and glaucoma are the most common findings in the elderly and can potentially lead to irreversible visual disablements up to blindness. To study the aging process and to identify possible therapeutic targets to counteract these diseases, the use of appropriate animal models is mandatory. Besides the most commonly used rodent species, a non-human primate, the common marmoset (Callithrix jacchus) emerged as a promising animal model of human aging over the last years. However, the visual aging process in this species is only partially characterized, especially with regard to retinal aberrations. Therefore, we assessed here for the first time potential changes in retinal morphology of the common marmoset of different age groups. By cell type specific immunolabeling, we analyzed different cell types and distributions, potential photoreceptor and ganglion cell loss, and structural reorganization. We detected no signs of age-related differences in staining patterns or densities of various cell populations. For example, there were no signs of photoreceptor degeneration, and there was only minimal sprouting of rod bipolar cells in aged retinas. Altogether, we describe here the maintenance of a stable neuronal architecture, distribution and number of different cell populations with only mild aberrations during the aging process in the common marmoset retina. These findings are in stark contrast to previously reported findings in rodent species and humans and deserve further investigations to identify the underlying mechanisms and possible therapeutic targets.
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Affiliation(s)
- Silke Haverkamp
- Department of Computational Neuroethology, Max Planck Institute for Neurobiology of Behavior—Caesar, Bonn, Germany
| | - Katja Reinhard
- Retinal Circuits and Optogenetics, Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Leo Peichl
- Institute of Clinical Neuroanatomy, Dr. Senckenbergische Anatomie, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Matthias Mietsch
- Laboratory Animal Science Unit, German Primate Center, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
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14
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Sinha T, Ikelle L, Makia MS, Crane R, Zhao X, Kakakhel M, Al-Ubaidi MR, Naash MI. Riboflavin deficiency leads to irreversible cellular changes in the RPE and disrupts retinal function through alterations in cellular metabolic homeostasis. Redox Biol 2022; 54:102375. [PMID: 35738087 PMCID: PMC9233280 DOI: 10.1016/j.redox.2022.102375] [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: 04/12/2022] [Revised: 06/13/2022] [Accepted: 06/14/2022] [Indexed: 10/25/2022] Open
Abstract
Ariboflavinosis is a pathological condition occurring as a result of riboflavin deficiency. This condition is treatable if detected early enough, but it lacks timely diagnosis. Critical symptoms of ariboflavinosis include neurological and visual manifestations, yet the effects of flavin deficiency on the retina are not well investigated. Here, using a diet induced mouse model of riboflavin deficiency, we provide the first evidence of how retinal function and metabolism are closely intertwined with riboflavin homeostasis. We find that diet induced riboflavin deficiency causes severe decreases in retinal function accompanied by structural changes in the neural retina and retinal pigment epithelium (RPE). This is preceded by increased signs of cellular oxidative stress and metabolic disorder, in particular dysregulation in lipid metabolism, which is essential for both photoreceptors and the RPE. Though many of these deleterious phenotypes can be ameliorated by riboflavin supplementation, our data suggests that some patients may continue to suffer from multiple pathologies at later ages. These studies provide an essential cellular and mechanistic foundation linking defects in cellular flavin levels with the manifestation of functional deficiencies in the visual system and paves the way for a more in-depth understanding of the cellular consequences of ariboflavinosis.
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Affiliation(s)
- Tirthankar Sinha
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Larissa Ikelle
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Ryan Crane
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Xue Zhao
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Mashal Kakakhel
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA.
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA.
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15
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Li R, Liang Y, Lin B. Accumulation of systematic TPM1 mediates inflammation and neuronal remodeling by phosphorylating PKA and regulating the FABP5/NF-κB signaling pathway in the retina of aged mice. Aging Cell 2022; 21:e13566. [PMID: 35148456 PMCID: PMC8920455 DOI: 10.1111/acel.13566] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 01/05/2022] [Accepted: 01/25/2022] [Indexed: 12/23/2022] Open
Abstract
The molecular mechanisms underlying functional decline during normal brain aging are poorly understood. Here, we identified the actin‐associated protein tropomyosin 1 (TPM1) as a new systemic pro‐aging factor associated with function deficits in normal aging retinas. Heterochronic parabiosis and blood plasma treatment confirmed that systemic factors regulated age‐related inflammatory responses and the ectopic dendritic sprouting of rod bipolar (RBC) and horizontal (HC) cells in the aging retina. Proteomic analysis revealed that TPM1 was a potential systemic molecule underlying structural and functional deficits in the aging retina. Recombinant TPM1 protein administration accelerated the activation of glial cells, the dendritic sprouting of RBCs and HCs and functional decline in the retina of young mice, whereas anti‐TPM1 neutralizing antibody treatment ameliorated age‐related structural and function changes in the retina of aged mice. Old mouse plasma (OMP) induced glial cell activation and the dendritic outgrowth of RBCs and HCs in young mice, and yet TMP1‐depleted OMP failed to reproduce the similar effect in young mice. These results confirmed that TPM1 was a systemic pro‐aging factor. Moreover, we demonstrated that systematic TPM1 was an immune‐related molecule, which elicited endogenous TPM1 expression and inflammation by phosphorylating PKA and regulating FABP5/NF‐κB signaling pathway in normal aging retinas. Interestingly, we observed TPM1 upregulation and the ectopic dendritic sprouting of RBCs and HCs in young mouse models of Alzheimer's disease, indicating a potential role of TPM1 in age‐related neurodegenerative diseases. Our data indicate that TPM1 could be targeted for combating the aging process.
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Affiliation(s)
- Rong Li
- School of Optometry The Hong Kong Polytechnic University Kowloon Hong Kong
| | - Yuxiang Liang
- The State Key Laboratory of Brain and Cognitive Sciences The University of Hong Kong Pok Fu Lam Hong Kong
| | - Bin Lin
- School of Optometry The Hong Kong Polytechnic University Kowloon Hong Kong
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16
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Mathew D, Luo Q, Bhatwadekar AD. Circadian Rhythm Disruption Results in Visual Dysfunction. FASEB Bioadv 2022; 4:364-378. [PMID: 35664832 PMCID: PMC9164246 DOI: 10.1096/fba.2021-00125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 01/19/2022] [Accepted: 01/26/2022] [Indexed: 11/14/2022] Open
Abstract
Artificial light has been increasingly in use for the past 70 years. The aberrant light exposure and round‐the‐clock nature of work lead to the disruption of biological clock. Circadian rhythm disruption (CRD) contributes to multiple metabolic and neurodegenerative diseases. However, its effect on vision is not understood. Moreover, the mammalian retina possesses an autonomous clock that could be reset with light exposure. We evaluated the impact of CRD on retinal morphology, physiology, and vision after housing mice in a disruption inducing shorter light/dark cycle (L10:D10). Interestingly, the mice under L10:D10 exhibited three different entrainment behaviors; “entrained,” “free‐running,” and “zigzagging.” These behavior groups under CRD exhibited reduced visual acuity, retinal thinning, and a decrease in the number of photoreceptors. Intriguingly, the electroretinogram response was decreased only in the mice exhibiting “entrained” behavior. The retinal proteome showed distinct changes with each entrainment behavior, and there was a dysfunctional oxidative stress‐antioxidant mechanism. These results demonstrate that CRD alters entrainment behavior and leads to visual dysfunction in mice. Our studies uniquely show the effect of entrainment behavior on retinal physiology. Our data have broader implications in understanding and mitigating the impact of CRD on vision and its potential role in the etiology of retinal diseases.
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Affiliation(s)
- Deepa Mathew
- Department of Ophthalmology Indiana University Indianapolis IN USA
| | - Qianyi Luo
- Department of Ophthalmology Indiana University Indianapolis IN USA
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17
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Dai C, Waduge P, Ji L, Huang C, He Y, Tian H, Zuniga-Sanchez E, Bhatt A, Pang IH, Su G, Webster KA, Li W. Secretogranin III stringently regulates pathological but not physiological angiogenesis in oxygen-induced retinopathy. Cell Mol Life Sci 2022; 79:63. [PMID: 35006382 PMCID: PMC9007175 DOI: 10.1007/s00018-021-04111-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/29/2021] [Accepted: 12/17/2021] [Indexed: 01/12/2023]
Abstract
Conventional angiogenic factors, such as vascular endothelial growth factor (VEGF), regulate both pathological and physiological angiogenesis indiscriminately, and their inhibitors may elicit adverse side effects. Secretogranin III (Scg3) was recently reported to be a diabetes-restricted VEGF-independent angiogenic factor, but the disease selectivity of Scg3 in retinopathy of prematurity (ROP), a retinal disease in preterm infants with concurrent pathological and physiological angiogenesis, was not defined. Here, using oxygen-induced retinopathy (OIR) mice, a surrogate model of ROP, we quantified an exclusive binding of Scg3 to diseased versus healthy developing neovessels that contrasted sharply with the ubiquitous binding of VEGF. Functional immunohistochemistry visualized Scg3 binding exclusively to disease-related disorganized retinal neovessels and neovascular tufts, whereas VEGF bound to both disorganized and well-organized neovessels. Homozygous deletion of the Scg3 gene showed undetectable effects on physiological retinal neovascularization but markedly reduced the severity of OIR-induced pathological angiogenesis. Furthermore, anti-Scg3 humanized antibody Fab (hFab) inhibited pathological angiogenesis with similar efficacy to anti-VEGF aflibercept. Aflibercept dose-dependently blocked physiological angiogenesis in neonatal retinas, whereas anti-Scg3 hFab was without adverse effects at any dose and supported a therapeutic window at least 10X wider than that of aflibercept. Therefore, Scg3 stringently regulates pathological but not physiological angiogenesis, and anti-Scg3 hFab satisfies essential criteria for development as a safe and effective disease-targeted anti-angiogenic therapy for ROP.
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Affiliation(s)
- Chang Dai
- Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA.,Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida, USA
| | - Prabuddha Waduge
- Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA.,Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida, USA
| | - Liyang Ji
- Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA.,Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida, USA
| | - Chengchi Huang
- Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA
| | - Ye He
- Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida, USA
| | - Hong Tian
- Everglades Biopharma, LLC, Houston, Texas, USA
| | - Elizabeth Zuniga-Sanchez
- Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA
| | - Amit Bhatt
- Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA.,Texas Children Hospital, Baylor College of Medicine, Houston, Texas, USA
| | - Iok-Hou Pang
- Dept. of Pharmaceutical Sciences, North Texas Eye Research Institute, University of North Texas, Fort Worth, Texas, USA
| | - Guanfang Su
- Department of Ophthalmology, The Second Hospital of Jilin University, #218 Ziqiang Street, Changchun, Jilin, China
| | - Keith A. Webster
- Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA.,Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida, USA.,Everglades Biopharma, LLC, Houston, Texas, USA
| | - Wei Li
- Cullen Eye Institute, Department of Ophthalmology, Baylor College of Medicine, Houston, Texas, USA.,Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida, USA
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18
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mTORC1 Activation in Chx10-Specific Tsc1 Knockout Mice Accelerates Retina Aging and Degeneration. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:6715758. [PMID: 34777691 PMCID: PMC8589503 DOI: 10.1155/2021/6715758] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 10/14/2021] [Accepted: 10/25/2021] [Indexed: 11/23/2022]
Abstract
Age-associated decline in retina function is largely responsible for the irreversible vision deterioration in the elderly population. It is also an important risk factor for the development of degenerative and angiogenic diseases. However, the molecular mechanisms involved in the process of aging in the retina remain largely elusive. This study investigated the role of mTORC1 signaling in aging of the retina. We showed that mTORC1 was activated in old-aged retina, particularly in the ganglion cells. The role of mTORC1 activation was further investigated in Chx10-Cre;Tsc1fx/fx mouse (Tsc1-cKO). Activation of mTORC1 was found in bipolar and some of the ganglion and amacrine cells in the adult Tsc1-cKO retina. Bipolar cell hypertrophy and Müller gliosis were observed in Tsc1-cKO since 6 weeks of age. The abnormal endings of bipolar cell dendritic tips at the outer nuclear layer resembled that of the old-aged mice. Microglial cell activation became evident in 6-week-old Tsc1-cKO. At 5 months, the Tsc1-cKO mice exhibited advanced features of old-aged retina, including the expression of p16Ink4a and p21, expression of SA-β-gal in ganglion cells, decreased photoreceptor cell numbers, decreased electroretinogram responses, increased oxidative stress, microglial cell activation, and increased expression of immune and inflammatory genes. Inhibition of microglial cells by minocycline partially prevented photoreceptor cell loss and restored the electroretinogram responses. Collectively, our study showed that the activation of mTORC1 signaling accelerated aging of the retina by both cell autonomous and nonautonomous mechanisms. Our study also highlighted the role of microglia cells in driving the decline in retina function.
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19
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Peng WH, Liao ML, Huang WC, Liu PK, Levi SR, Tseng YJ, Lee CY, Yeh LK, Chen KJ, Chien CL, Wang NK. Conditional Deletion of Activating Rearranged During Transfection Receptor Tyrosine Kinase Leads to Impairment of Photoreceptor Ribbon Synapses and Disrupted Visual Function in Mice. Front Neurosci 2021; 15:728905. [PMID: 34803580 PMCID: PMC8602685 DOI: 10.3389/fnins.2021.728905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/11/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: The rearranged during transfection (RET) receptor tyrosine kinase plays a key role in transducing signals related to cell growth and differentiation. Ret mutant mice show abnormal retinal activity and abnormal levels and morphology of bipolar cells, yet die on the 21st day after birth as a result of renal underdevelopment. To extend the observation period, we generated the Ret conditional knockout Chx10-Cre;C-Ret lx/lx mouse model and analyzed the retinal function and morphological changes in mature and aging Chx10-Cre;C-Ret lx/lx mice. Methods: Retina-specific depletion of Ret was achieved using mice with floxed alleles of the Ret gene with CHX10-driven Cre recombinase; floxed mice without Cre expression were used as controls. Retinal function was examined using electroretinography (ERG), and 2-, 4-, 12-, and 24-month-old mice were analyzed by hematoxylin staining and immunohistochemistry to evaluate retinal morphological alterations. The ultrastructure of photoreceptor synapses was evaluated using electron microscopy. Results: The results of the ERG testing showed that b-wave amplitudes were reduced in Chx10-Cre;C-Ret lx/lx mice, whereas a-waves were not affected. A histopathological analysis revealed a thinner and disorganized outer plexiform layer at the ages of 12 and 24 months in Chx10-Cre;C-Ret lx/lx mice. Moreover, the data provided by immunohistochemistry showed defects in the synapses of photoreceptor cells. This result was confirmed at the ultrastructural level, thus supporting the participation of Ret in the morphological changes of the synaptic ribbon. Conclusion: Our results provide evidence of the role of Ret in maintaining the function of the retina, which was essential for preserving the structure of the synaptic ribbon and supporting the integrity of the outer plexiform layer.
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Affiliation(s)
- Wei-Hao Peng
- School of Medicine for International Students, College of Medicine, I-Shou University, Kaohsiung, Taiwan
| | - Meng-Lin Liao
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Wan-Chun Huang
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Pei-Kang Liu
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, NY, United States
| | - Sarah R. Levi
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, NY, United States
| | - Yun-Ju Tseng
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, NY, United States
| | - Chia-Ying Lee
- Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Lung-Kun Yeh
- Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Kuan-Jen Chen
- Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chung-Liang Chien
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Nan-Kai Wang
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, NY, United States
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20
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Joly S, Rodriguez L, Pernet V. The Lack of Amyloidogenic Activity Is Persistent in Old WT and APP swe/PS1ΔE9 Mouse Retinae. Int J Mol Sci 2021; 22:11344. [PMID: 34768774 PMCID: PMC8583210 DOI: 10.3390/ijms222111344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/16/2021] [Accepted: 10/19/2021] [Indexed: 11/16/2022] Open
Abstract
We have previously reported that vision decline was not associated with amyloidogenesis processing in aging C57BL/6J wild-type (WT) mice and in a mouse model of Alzheimer's disease, the APPswe/PS1ΔE9 transgenic mouse model (APP/PS1). This conclusion was drawn using middle-aged (10-13 months old) mice. Here, we hypothesized that compared with hippocampal and cortical neurons, the weak amyloidogenic activity of retinal neurons may result in a detectable release of amyloid β (Aβ) only in aged mice, i.e., between 14 and 24 months of age. The aim of the present study was thus to follow potential activity changes in the amyloidogenic and nonamyloidogenic pathways of young (4 months) and old (20-24 months) WT and APP/PS1 mice. Our results showed that in spite of retinal activity loss reported by electroretinogram (ERG) recordings, the level of amyloid beta precursor protein (APP) and its derivatives did not significantly vary in the eyes of old vs. young mice. Strikingly, the ectopic expression of human APPswe in APP/PS1 mice did not allow us to detect Aβ monomers at 23 months. In contrast, Aβ was observed in hippocampal and cortical tissues at this age but not at 4 months of life. In contrast, optic nerve transection-induced retinal ganglion cell injury significantly affected the level of retinal APP and the secretion of soluble APP alpha in the vitreous. Collectively, these results suggest that the amyloidogenic and nonamyloidogenic pathways are not involved in visual function decline in aging mice. In WT and APP/PS1 mice, it is proposed that retinal neurons do not have the capacity to secrete Aβ in contrast with other cortical and hippocampal neurons.
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Affiliation(s)
- Sandrine Joly
- Centre de Recherche du CHU de Québec-Université Laval and Department of Molecular Medicine, Faculty of Medicine, Université Laval, Quebec, QC G1V 4G2, Canada; (S.J.); (L.R.)
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland
| | - Léa Rodriguez
- Centre de Recherche du CHU de Québec-Université Laval and Department of Molecular Medicine, Faculty of Medicine, Université Laval, Quebec, QC G1V 4G2, Canada; (S.J.); (L.R.)
| | - Vincent Pernet
- Centre de Recherche du CHU de Québec-Université Laval and Department of Molecular Medicine, Faculty of Medicine, Université Laval, Quebec, QC G1V 4G2, Canada; (S.J.); (L.R.)
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland
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21
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Townes-Anderson E, Halasz E, Wang W, Zarbin M. Coming of Age for the Photoreceptor Synapse. Invest Ophthalmol Vis Sci 2021; 62:24. [PMID: 34550300 PMCID: PMC8475281 DOI: 10.1167/iovs.62.12.24] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Purpose To discuss the potential contribution of rod and cone synapses to the loss of visual function in retinal injury and disease. Methods The published literature and the authors' own work were reviewed. Results Retinal detachment is used as a case study of rod spherule and cone pedicle plasticity after injury. Both rod and cone photoreceptors terminals are damaged after detachment although the structural changes observed are only partially overlapping. For second-order neurons, only those associated with rod spherules respond consistently to injury by remodeling. Examination of signaling pathways involved in plasticity of conventional synapses and in neural development has been and may continue to be productive in discovering novel therapeutic targets. Rho kinase (ROCK) inhibition is an example of therapy that may reduce synaptic damage by preserving normal synaptic structure of rod and cone cells. Conclusions We hypothesize that synaptic damage contributes to poor visual restoration after otherwise successful anatomical repair of retinal detachment. A similar situation may exist for patients with degenerative retinal disease. Thus, synaptic structure and function should be routinely studied, as this information may disclose therapeutic strategies to mitigate visual loss.
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Affiliation(s)
- Ellen Townes-Anderson
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey, United States
| | - Eva Halasz
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey, United States
| | - Weiwei Wang
- Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard University, Boston, Massachusetts, United States
| | - Marco Zarbin
- Institute of Ophthalmology and Visual Science, Rutgers New Jersey Medical School, Newark, New Jersey, United States
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22
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Kovács-Valasek A, Pöstyéni E, Dénes V, Mester A, Sétáló G, Gábriel R. Age-Related Alterations of Proteins in Albino Wistar Rat Retina. Cells Tissues Organs 2021; 210:135-150. [PMID: 34218223 DOI: 10.1159/000515447] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 02/04/2021] [Indexed: 01/05/2023] Open
Abstract
Imbalance of homeostasis causes permanent changes in the body with time. The central nervous system is especially prone to these changes since it possesses limited regenerative capacity. In the retina, neurons are damaged during the aging process, and this eventually leads to deterioration of vision. In our 2-year-long study, we examined genetically closely related rat individuals to disclose the hidden retinal causes of age-associated visual dysfunction. Morphometric analysis showed significant reduction of the retina thickness with aging, particularly that of the inner plexiform layer. To reveal changes between the age groups, we used immunohistochemistry against vesicular glutamate transporter 1 protein for photoreceptor and bipolar cell terminals, Brn3a for ganglion cells, calbindin 28 kDa for horizontal cells, parvalbumin for AII amacrines, protein kinase Cα for rod bipolar cells, tyrosine hydroxylase for dopaminergic cells, glial fibrillary acidic protein for glial cells, and peanut-agglutinin labeling for cones. The most significant decrease was observed in the density of photoreceptor and the ganglion cells in the aging process. By using immunocytochemistry and western blot technique, we observed that calbindin and vesicular glutamate transporter 1 protein staining do not change much with aging; tyrosine hydroxylase, parvalbumin and calretinin showed the highest immunoreactivity during the midlife period. Most interestingly, the level of glial fibrillary acidic protein also changes similarly to the previously named markers. Our results provide further evidence that protein content is modified at least in some cell populations of the rat retina, and the number of retinal cells declined with aging. We conclude that senescence alone may cause structural and functional damage in the retinal tissue.
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Affiliation(s)
- Andrea Kovács-Valasek
- Department of Experimental Zoology and Neurobiology, Institute of Biology, Faculty of Sciences, University of Pécs, Pécs, Hungary.,János Szentágothai Research Centre, University of Pécs, Pécs, Hungary
| | - Etelka Pöstyéni
- Department of Experimental Zoology and Neurobiology, Institute of Biology, Faculty of Sciences, University of Pécs, Pécs, Hungary
| | - Viktória Dénes
- Department of Experimental Zoology and Neurobiology, Institute of Biology, Faculty of Sciences, University of Pécs, Pécs, Hungary
| | - Adrienn Mester
- Department of Experimental Zoology and Neurobiology, Institute of Biology, Faculty of Sciences, University of Pécs, Pécs, Hungary
| | - György Sétáló
- Department of Medical Biology, Medical School, University of Pécs, Pécs, Hungary.,János Szentágothai Research Centre, University of Pécs, Pécs, Hungary
| | - Róbert Gábriel
- Department of Experimental Zoology and Neurobiology, Institute of Biology, Faculty of Sciences, University of Pécs, Pécs, Hungary.,János Szentágothai Research Centre, University of Pécs, Pécs, Hungary
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23
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Kumar S, Ramakrishnan H, Viswanathan S, Akopian A, Bloomfield SA. Neuroprotection of the Inner Retina Also Prevents Secondary Outer Retinal Pathology in a Mouse Model of Glaucoma. Invest Ophthalmol Vis Sci 2021; 62:35. [PMID: 34297802 PMCID: PMC8300060 DOI: 10.1167/iovs.62.9.35] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 06/24/2021] [Indexed: 12/02/2022] Open
Abstract
Purpose We examined structural and functional changes in the outer retina of a mouse model of glaucoma. We examined whether these changes are a secondary consequence of damage in the inner retina and whether neuroprotection of the inner retina also prevents outer retinal changes. Methods We used an established microbead occlusion model of glaucoma whereby intraocular pressure (IOP) was elevated. Specific antibodies were used to label rod and cone bipolar cells (BCs), horizontal cells (HCs), and retinal ganglion cells (RGCs), as well as synaptic components in control and glaucomatous eyes, to assess structural damage and cell loss. ERG recordings were made to assess outer retina function. Results We found structural and functional damage of BCs, including significant cell loss and dendritic/axonal remodeling of HCs, following IOP elevation. The first significant loss of both BCs occurred at 4 to 5 weeks after microbead injection. However, early changes in the dendritic structure of RGCs were observed at 3 weeks, but significant changes in the rod BC axon terminal structure were not seen until 4 weeks. We found that protection of inner retinal neurons in glaucomatous eyes by pharmacological blockade of gap junctions or genetic ablation of connexin 36 largely prevented outer retinal damage. Conclusions Together, our results indicate that outer retinal impairments in glaucoma are a secondary sequalae of primary damage in the inner retina. The finding that neuroprotection of the inner retina can also prevent outer retinal damage has important implications with regard to the targets for effective neuroprotective therapy.
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Affiliation(s)
- Sandeep Kumar
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
| | - Hariharasubramanian Ramakrishnan
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
| | - Suresh Viswanathan
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
| | - Abram Akopian
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
| | - Stewart A. Bloomfield
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, New York, United States
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24
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Tsukamoto Y, Iseki K, Omi N. Helical Fasciculation of Bipolar and Horizontal Cell Neurites for Wiring With Photoreceptors in Macaque and Mouse Retinas. Invest Ophthalmol Vis Sci 2021; 62:31. [PMID: 33507230 PMCID: PMC7846946 DOI: 10.1167/iovs.62.1.31] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The three-dimensional configurations of rod and cone bipolar cell (BC) dendrites and horizontal cell (HC) processes outside rod and cone synaptic terminals have not been fully elucidated. We reveal how these neurites are mutually arranged to coordinate formation and maintenance of the postsynaptic complex of ribbon synapses in mouse and monkey retinas. Methods Serial section transmission electron microscopy was utilized to reconstruct BC and HC neurites in macaque monkey and mouse, including metabotropic glutamate receptor 6 (mGluR6)-knockout mice. Results Starting from sporadically distributed branching points, rod BC and HC neurites (B and H, respectively) took specific paths to rod spherules by gradually adjusting their mutual positions, which resulted in a closed alternating pattern of H‒B‒H‒B neurites at the rod spherule aperture. This order corresponded to the array of elements constituting the postsynaptic complex of ribbon synapses. We identified novel helical coils of HC processes surrounding the rod BC dendrite in both mouse and macaque retinas, and these structures occurred more frequently in mGluR6-knockout than wild-type mouse retinas. Horizontal cell processes also formed hook-like protrusions that encircled cone BC and HC neurites below the cone pedicles in the macaque retina. Conclusions Bipolar and horizontal cell neurites take specific paths to adjust their mutual positions at the rod spherule aperture. Some HC processes are helically coiled around rod BC dendrites or form hook-like protrusions around cone BC dendrites and HC processes. Loss of mGluR6 signaling may be one factor promoting unbalanced neurite growth and compensatory neurite coiling.
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Affiliation(s)
- Yoshihiko Tsukamoto
- Department of Biology, Hyogo College of Medicine, Mukogawa, Nishinomiya, Hyogo, Japan.,Studio EM-Retina, Satonaka, Nishinomiya, Hyogo, Japan
| | - Kyoko Iseki
- Laboratory for Retinal Regeneration, RIKEN Center for Developmental Biology, Minatojima Minamimachi, Chuo-ku, Kobe, Hyogo, Japan
| | - Naoko Omi
- Studio EM-Retina, Satonaka, Nishinomiya, Hyogo, Japan
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25
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Burger CA, Jiang D, Mackin RD, Samuel MA. Development and maintenance of vision's first synapse. Dev Biol 2021; 476:218-239. [PMID: 33848537 DOI: 10.1016/j.ydbio.2021.04.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/02/2021] [Accepted: 04/03/2021] [Indexed: 12/21/2022]
Abstract
Synapses in the outer retina are the first information relay points in vision. Here, photoreceptors form synapses onto two types of interneurons, bipolar cells and horizontal cells. Because outer retina synapses are particularly large and highly ordered, they have been a useful system for the discovery of mechanisms underlying synapse specificity and maintenance. Understanding these processes is critical to efforts aimed at restoring visual function through repairing or replacing neurons and promoting their connectivity. We review outer retina neuron synapse architecture, neural migration modes, and the cellular and molecular pathways that play key roles in the development and maintenance of these connections. We further discuss how these mechanisms may impact connectivity in the retina.
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Affiliation(s)
- Courtney A Burger
- Huffington Center on Aging, Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Danye Jiang
- Huffington Center on Aging, Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Robert D Mackin
- Huffington Center on Aging, Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Melanie A Samuel
- Huffington Center on Aging, Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA.
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26
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Sugita Y, Yamamoto H, Maeda Y, Furukawa T. Influence of Aging on the Retina and Visual Motion Processing for Optokinetic Responses in Mice. Front Neurosci 2020; 14:586013. [PMID: 33335469 PMCID: PMC7736246 DOI: 10.3389/fnins.2020.586013] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 11/10/2020] [Indexed: 11/13/2022] Open
Abstract
The decline in visual function due to normal aging impacts various aspects of our daily lives. Previous reports suggest that the aging retina exhibits mislocalization of photoreceptor terminals and reduced amplitudes of scotopic and photopic electroretinogram (ERG) responses in mice. These abnormalities are thought to contribute to age-related visual impairment; however, the extent to which visual function is impaired by aging at the organismal level is unclear. In the present study, we focus on the age-related changes of the optokinetic responses (OKRs) in visual processing. Moreover, we investigated the initial and late phases of the OKRs in young adult (2-3 months old) and aging mice (21-24 months old). The initial phase was evaluated by measuring the open-loop eye velocity of OKRs using sinusoidal grating patterns of various spatial frequencies (SFs) and moving at various temporal frequencies (TFs) for 0.5 s. The aging mice exhibited initial OKRs with a spatiotemporal frequency tuning that was slightly different from those in young adult mice. The late-phase OKRs were investigated by measuring the slow-phase velocity of the optokinetic nystagmus evoked by sinusoidal gratings of various spatiotemporal frequencies moving for 30 s. We found that optimal SF and TF in the normal aging mice are both reduced compared with those in young adult mice. In addition, we measured the OKRs of 4.1G-null (4.1G -/-) mice, in which mislocalization of photoreceptor terminals is observed even at the young adult stage. We found that the late phase OKR was significantly impaired in 4.1G - / - mice, which exhibit significantly reduced SF and TF compared with control mice. These OKR abnormalities observed in 4.1G - / - mice resemble the abnormalities found in normal aging mice. This finding suggests that these mice can be useful mouse models for studying the aging of the retinal tissue and declining visual function. Taken together, the current study demonstrates that normal aging deteriorates to visual motion processing for both the initial and late phases of OKRs. Moreover, it implies that the abnormalities of the visual function in the normal aging mice are at least partly due to mislocalization of photoreceptor synapses.
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Affiliation(s)
- Yuko Sugita
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Haruka Yamamoto
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Yamato Maeda
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Takahisa Furukawa
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, Japan
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27
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Homeostatic Plasticity Shapes the Retinal Response to Photoreceptor Degeneration. Curr Biol 2020; 30:1916-1926.e3. [PMID: 32243858 DOI: 10.1016/j.cub.2020.03.033] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 02/28/2020] [Accepted: 03/12/2020] [Indexed: 11/21/2022]
Abstract
Homeostatic plasticity stabilizes input and activity levels during neural development, but whether it can restore connectivity and preserve circuit function during neurodegeneration is unknown. Photoreceptor degeneration is the most common cause of blindness in the industrialized world. Visual deficits are dominated by cone loss, which progresses slowly, leaving a window during which rewiring of second-order neurons (i.e., bipolar cells) could preserve function. Here we establish a transgenic model to induce cone degeneration with precise control and analyze bipolar cell responses and their effects on vision through anatomical reconstructions, in vivo electrophysiology, and behavioral assays. In young retinas, we find that three bipolar cell types precisely restore input synapse numbers when 50% of cones degenerate but one does not. Of the three bipolar cell types that rewire, two contact new cones within stable dendritic territories, whereas one expands its dendrite arbors to reach new partners. In mature retinas, only one of four bipolar cell types rewires homeostatically. This steep decline in homeostatic plasticity is accompanied by reduced light responses of bipolar cells and deficits in visual behaviors. By contrast, light responses and behavioral performance are preserved when cones degenerate in young mice. Our results reveal unexpected cell type specificity and a steep maturational decline of homeostatic plasticity. The effect of homeostatic plasticity on functional outcomes identify it as a promising therapeutic target for retinal and other neurodegenerative diseases.
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28
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Appelbaum T, Santana E, Aguirre GD. Critical Decrease in the Level of Axon Guidance Receptor ROBO1 in Rod Synaptic Terminals Is Followed by Axon Retraction. Invest Ophthalmol Vis Sci 2020; 61:11. [PMID: 32176262 PMCID: PMC7405958 DOI: 10.1167/iovs.61.3.11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/14/2019] [Indexed: 12/24/2022] Open
Abstract
Purpose To define remodeling of photoreceptor synaptic terminals and second-order retinal neurons in canine X-linked progressive retinal atrophy 1 caused by a five-nucleotide deletion in the RPGR exon ORF15. Methods Retinas of normal and mutant dogs were used for gene expression, Western blot, and immunohistochemistry. Cell-specific markers were used to examine disease-dependent retinal remodeling. Results In mutant retinas, a number of rod axon terminals retract into the outer nuclear layer. This neuritic atrophy preceded significant loss of rods and was evident early in disease. Rod bipolar and horizontal cell processes were found to extend into the outer nuclear layer, where they seemed to form contacts with the spherules of rod photoreceptors. No ectopic rewiring was observed. Because cytoskeletal reorganization was previously shown to underlie photoreceptor axon retraction, we examined normal and mutant retinas for expression of axon guidance receptors ROBO1 and ROBO2, which are known to regulate actin cytoskeleton dynamics. We found that the overall expression of both ROBO1 and ROBO2 is retained at the same level in premature and fully developed normal retinas. However, analysis of predisease and early disease retinas identified markedly decreased levels of ROBO1 in rod spherules compared with controls. In contrast, no differences in ROBO1 signals were noted in cone pedicles in normal and mutant retinas, where ROBO1 levels remained similarly low. Conclusions Depletion of ROBO1 in rod synaptic terminals correlates with the remodeling of axonal and dendritic processes in the outer retina of dogs with X-linked progressive retinal atrophy 1 and may play a role in the retraction of rod axons.
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Affiliation(s)
- Tatyana Appelbaum
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Evelyn Santana
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Gustavo D. Aguirre
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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29
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Chan K, Hoon M, Pattnaik BR, Ver Hoeve JN, Wahlgren B, Gloe S, Williams J, Wetherbee B, Kiland JA, Vogel KR, Jansen E, Salomons G, Walters D, Roullet JB, Gibson K M, McLellan GJ. Vigabatrin-Induced Retinal Functional Alterations and Second-Order Neuron Plasticity in C57BL/6J Mice. Invest Ophthalmol Vis Sci 2020; 61:17. [PMID: 32053727 PMCID: PMC7326505 DOI: 10.1167/iovs.61.2.17] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 11/07/2019] [Indexed: 12/13/2022] Open
Abstract
Purpose Vigabatrin (VGB) is an effective antiepileptic that increases concentrations of inhibitory γ-aminobutyric acid (GABA) by inhibiting GABA transaminase. Reports of VGB-associated visual field loss limit its clinical usefulness, and retinal toxicity studies in laboratory animals have yielded conflicting results. Methods We examined the functional and morphologic effects of VGB in C57BL/6J mice that received either VGB or saline IP from 10 to 18 weeks of age. Retinal structure and function were assessed in vivo by optical coherence tomography (OCT), ERG, and optomotor response. After euthanasia, retinas were processed for immunohistochemistry, and retinal GABA, and VGB quantified by mass spectrometry. Results No significant differences in visual acuity or total retinal thickness were identified between groups by optomotor response or optical coherence tomography, respectively. After 4 weeks of VGB treatment, ERG b-wave amplitude was enhanced, and amplitudes of oscillatory potentials were reduced. Dramatic rod and cone bipolar and horizontal cell remodeling, with extension of dendrites into the outer nuclear layer, was observed in retinas of VGB-treated mice. VGB treatment resulted in a mean 3.3-fold increase in retinal GABA concentration relative to controls and retinal VGB concentrations that were 20-fold greater than brain. Conclusions No evidence of significant retinal thinning or ERG a- or b-wave deficits were apparent, although we describe significant alterations in ERG b-wave and oscillatory potentials and in retinal cell morphology in VGB-treated C57BL/6J mice. The dramatic concentration of VGB in retina relative to the target tissue (brain), with a corresponding increase in retinal GABA, offers insight into the pathophysiology of VGB-associated visual field loss.
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Affiliation(s)
- Kore Chan
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
| | - Mrinalini Hoon
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
| | - Bikash R. Pattnaik
- McPherson Eye Research Institute, Madison, Wisconsin, United States
- Pediatrics Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - James N. Ver Hoeve
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
| | - Brad Wahlgren
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Shawna Gloe
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Jeremy Williams
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Brenna Wetherbee
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Julie A. Kiland
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Kara R. Vogel
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
| | - Erwin Jansen
- Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Gajja Salomons
- Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Dana Walters
- Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, Washington, United States
| | - Jean-Baptiste Roullet
- Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, Washington, United States
| | - K Michael Gibson
- Washington State University College of Pharmacy and Pharmaceutical Sciences, Spokane, Washington, United States
| | - Gillian J. McLellan
- Department of Ophthalmology & Visual Science, University of Wisconsin–Madison, Madison, Wisconsin, United States
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, United States
- McPherson Eye Research Institute, Madison, Wisconsin, United States
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30
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Macke EL, Henningsen E, Jessen E, Zumwalde NA, Landowski M, Western DE, Lee WH, Liu C, Gruenke NP, Doebley AL, Miller S, Pattnaik B, Ikeda S, Gumperz JE, Ikeda A. Loss of Chondroitin Sulfate Modification Causes Inflammation and Neurodegeneration in skt Mice. Genetics 2020; 214:121-134. [PMID: 31754016 PMCID: PMC6944401 DOI: 10.1534/genetics.119.302834] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 11/17/2019] [Indexed: 12/17/2022] Open
Abstract
One major aspect of the aging process is the onset of chronic, low-grade inflammation that is highly associated with age-related diseases. The molecular mechanisms that regulate these processes have not been fully elucidated. We have identified a spontaneous mutant mouse line, small with kinky tail (skt), that exhibits accelerated aging and age-related disease phenotypes including increased inflammation in the brain and retina, enhanced age-dependent retinal abnormalities including photoreceptor cell degeneration, neurodegeneration in the hippocampus, and reduced lifespan. By positional cloning, we identified a deletion in chondroitin sulfate synthase 1 (Chsy1) that is responsible for these phenotypes in skt mice. CHSY1 is a member of the chondroitin N-acetylgalactosaminyltransferase family that plays critical roles in the biosynthesis of chondroitin sulfate, a glycosaminoglycan (GAG) that is attached to the core protein to form the chondroitin sulfate proteoglycan (CSPG). Consistent with this function, the Chsy1 mutation dramatically decreases chondroitin sulfate GAGs in the retina and hippocampus. In addition, macrophage and neutrophil populations appear significantly altered in the bone marrow and spleen of skt mice, suggesting an important role for CHSY1 in the functioning of these immune cell types. Thus, our study reveals a previously unidentified impact of CHSY1 in the retina and hippocampus. Specifically, chondroitin sulfate (CS) modification of proteins by CHSY1 appears critical for proper regulation of immune cells of the myeloid lineage and for maintaining the integrity of neuronal tissues, since a defect in this gene results in increased inflammation and abnormal phenotypes associated with age-related diseases.
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Affiliation(s)
- Erica L Macke
- Department of Medical Genetics, University of Wisconsin-Madison, Wisconsin 53706
| | - Erika Henningsen
- Department of Medical Genetics, University of Wisconsin-Madison, Wisconsin 53706
| | - Erik Jessen
- Department of Medical Genetics, University of Wisconsin-Madison, Wisconsin 53706
- Department of Biochemistry, University of Wisconsin-Madison, Wisconsin 53706
| | - Nicholas A Zumwalde
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Wisconsin 53706
| | - Michael Landowski
- Department of Medical Genetics, University of Wisconsin-Madison, Wisconsin 53706
| | - Daniel E Western
- Department of Medical Genetics, University of Wisconsin-Madison, Wisconsin 53706
| | - Wei-Hua Lee
- Department of Medical Genetics, University of Wisconsin-Madison, Wisconsin 53706
| | - Che Liu
- Institute for Molecular Virology, University of Wisconsin-Madison, Wisconsin 53706
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Wisconsin 53706
| | - Nathan P Gruenke
- Department of Medical Genetics, University of Wisconsin-Madison, Wisconsin 53706
| | - Anna-Lisa Doebley
- Department of Medical Genetics, University of Wisconsin-Madison, Wisconsin 53706
| | - Samuel Miller
- Department of Medical Genetics, University of Wisconsin-Madison, Wisconsin 53706
| | - Bikash Pattnaik
- Department of Pediatrics, University of Wisconsin-Madison, Wisconsin 53706
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Wisconsin 53706
- McPherson Eye Research Institute, University of Wisconsin-Madison, Wisconsin 53706
| | - Sakae Ikeda
- Department of Medical Genetics, University of Wisconsin-Madison, Wisconsin 53706
- McPherson Eye Research Institute, University of Wisconsin-Madison, Wisconsin 53706
| | - Jenny E Gumperz
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Wisconsin 53706
| | - Akihiro Ikeda
- Department of Medical Genetics, University of Wisconsin-Madison, Wisconsin 53706
- McPherson Eye Research Institute, University of Wisconsin-Madison, Wisconsin 53706
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31
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Laird JG, Gardner SH, Kopel AJ, Kerov V, Lee A, Baker SA. Rescue of Rod Synapses by Induction of Cav Alpha 1F in the Mature Cav1.4 Knock-Out Mouse Retina. Invest Ophthalmol Vis Sci 2019; 60:3150-3161. [PMID: 31335952 PMCID: PMC6656410 DOI: 10.1167/iovs.19-27226] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 06/24/2019] [Indexed: 01/10/2023] Open
Abstract
Purpose Cav1.4 is a voltage-gated calcium channel clustered at the presynaptic active zones of photoreceptors. Cav1.4 functions in communication by mediating the Ca2+ influx that triggers neurotransmitter release. It also aids in development since rod ribbon synapses do not form in Cav1.4 knock-out mice. Here we used a rescue strategy to investigate the ability of Cav1.4 to trigger synaptogenesis in both immature and mature mouse rods. Methods In vivo electroporation was used to transiently express Cav α1F or tamoxifen-inducible Cav α1F in a subset of Cav1.4 knock-out mouse rods. Synaptogenesis was assayed using morphologic markers and a vision-guided water maze. Results We found that introduction of Cav α1F to knock-out terminals rescued synaptic development as indicated by PSD-95 expression and elongated ribbons. When expression of Cav α1F was induced in mature animals, we again found restoration of PSD-95 and elongated ribbons. However, the induced expression of Cav α1F led to diffuse distribution of Cav α1F in the terminal instead of being clustered beneath the ribbon. Approximately a quarter of treated animals passed the water maze test, suggesting the rescue of retinal signaling in these mice. Conclusions These data confirm that Cav α1F expression is necessary for rod synaptic terminal development and demonstrate that rescue is robust even in adult animals with late stages of synaptic disease. The degree of rod synaptic plasticity seen here should be sufficient to support future vision-restoring treatments such as gene or cell replacement that will require photoreceptor synaptic rewiring.
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Affiliation(s)
- Joseph G. Laird
- Department of Biochemistry, University of Iowa, Iowa City, United States
| | - Sarah H. Gardner
- Department of Biochemistry, University of Iowa, Iowa City, United States
| | - Ariel J. Kopel
- Department of Biochemistry, University of Iowa, Iowa City, United States
| | - Vasily Kerov
- Molecular Physiology and Biophysics, University of Iowa, Iowa City, United States
| | - Amy Lee
- Molecular Physiology and Biophysics, University of Iowa, Iowa City, United States
- Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, United States
- Department of Neurology, University of Iowa, Iowa City, United States
- Iowa Neuroscience Institute, University of Iowa, Iowa City, United States
| | - Sheila A. Baker
- Department of Biochemistry, University of Iowa, Iowa City, United States
- Iowa Neuroscience Institute, University of Iowa, Iowa City, United States
- Ophthalmology and Visual Sciences and the Institute for Vision Research, University of Iowa, Iowa City, United States
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32
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Zhang X, Zhu J, Chen X, Jie-Qiong Z, Li X, Luo L, Huang H, Liu W, Zhou X, Yan J, Lin S, Ye J. Interferon Regulatory Factor 3 Deficiency Induces Age-Related Alterations of the Retina in Young and Old Mice. Front Cell Neurosci 2019; 13:272. [PMID: 31281243 PMCID: PMC6596281 DOI: 10.3389/fncel.2019.00272] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 06/05/2019] [Indexed: 12/20/2022] Open
Abstract
Age-related changes in visual function and retina structure are very common in aged animals, but the underlying mechanisms of these changes remain unclear. Here we report that the expression of interferon regulatory factor 3 (IRF3), a critical immune regulatory factor, is dramatically down-regulated in mouse retinas during aging. To address the role of IRF3 in the retina, we examined the structure and function of retinas in young (3–4 months) and old (22–24 months) Irf3-/- mice in comparison to age-matched wildtype (WT) mice. We found that IRF3 deletion resulted in impaired electroretinogram (ERG) responses and decreased retinal thickness in both young and old mice. In addition, numerous synapses of the outer plexiform layer (OPL) were found obviously extending into outer nuclear layer (ONL) in Irf3-/- mice, along with a reduction of the average synapse density in the OPL. These changes suggest that IRF3 deletion may accelerate retinal senescence. In support of this hypothesis, a number of classic senescence-associated markers were found in remarkably elevated level in Irf3-/- retina, including p53, p16INK4a, inositol-requiring enzyme 1α (IREα), p-H2A.X and promyelocytic leukemia protein (PML). Overall, our results indicate that maintenance normal IRF3 levels is necessary for retinal structure and function and suggest that IRF3 is an important regulator of retinal senescence.
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Affiliation(s)
- Xi Zhang
- Department of Ophthalmology, Institute of Surgery Research, Army Medical Center of PLA (Daping Hospital), Army Medical University, Chongqing, China
| | - Jingyi Zhu
- Department of Ophthalmology, Institute of Surgery Research, Army Medical Center of PLA (Daping Hospital), Army Medical University, Chongqing, China
| | - Xianjun Chen
- Department of Histology and Embryology, Chongqing Key Laboratory of Neurobiology, Army Medical University, Chongqing, China
| | - Zhang Jie-Qiong
- Department of Ophthalmology, Institute of Surgery Research, Army Medical Center of PLA (Daping Hospital), Army Medical University, Chongqing, China
| | - Xue Li
- Department of Ophthalmology, Institute of Surgery Research, Army Medical Center of PLA (Daping Hospital), Army Medical University, Chongqing, China
| | - Linlin Luo
- Department of Ophthalmology, Institute of Surgery Research, Army Medical Center of PLA (Daping Hospital), Army Medical University, Chongqing, China
| | - Huang Huang
- Institute of Immunology, Army Medical University, Chongqing, China
| | - Wenyi Liu
- Department of Ophthalmology, Institute of Surgery Research, Army Medical Center of PLA (Daping Hospital), Army Medical University, Chongqing, China
| | - Xinyuan Zhou
- Institute of Immunology, Army Medical University, Chongqing, China
| | - Jun Yan
- Department of Ophthalmology, Institute of Surgery Research, Army Medical Center of PLA (Daping Hospital), Army Medical University, Chongqing, China
| | - Sen Lin
- Department of Ophthalmology, Institute of Surgery Research, Army Medical Center of PLA (Daping Hospital), Army Medical University, Chongqing, China
| | - Jian Ye
- Department of Ophthalmology, Institute of Surgery Research, Army Medical Center of PLA (Daping Hospital), Army Medical University, Chongqing, China
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Kim BJ, Grossman M, Song D, Saludades S, Pan W, Dominguez-Perez S, Dunaief JL, Aleman TS, Ying GS, Irwin DJ. Persistent and Progressive Outer Retina Thinning in Frontotemporal Degeneration. Front Neurosci 2019; 13:298. [PMID: 31019447 PMCID: PMC6459211 DOI: 10.3389/fnins.2019.00298] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 03/15/2019] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE While Alzheimer's disease is associated with inner retina thinning measured by spectral-domain optical coherence tomography (SD-OCT), our previous cross-sectional study suggested outer retina thinning in frontotemporal degeneration (FTD) patients compared to controls without neurodegenerative disease; we sought to evaluate longitudinal changes of this potential biomarker. METHODS SD-OCT retinal layer thicknesses were measured at baseline and after 1-2 years. Clinical criteria, genetic analysis, and a cerebrospinal fluid biomarker (total tau: β-amyloid) to exclude likely underlying Alzheimer's disease pathology were used to define a subgroup of predicted molecular pathology (i.e., tauopathy). Retinal layer thicknesses and rates of change in all FTD patients (n = 16 patients, 30 eyes) and the tauopathy subgroup (n = 9 patients,16 eyes) were compared to controls (n = 30 controls, 47 eyes) using a generalized linear model accounting for inter-eye correlation and adjusting for age, sex, and race. Correlations between retinal layer thicknesses and Mini-Mental State Examinations (MMSE) were assessed. RESULTS Compared to controls, returning FTD patients (143 vs. 130 μm, p = 0.005) and the tauopathy subgroup (143 vs. 128 μm, p = 0.03) had thinner outer retinas but similar inner layer thicknesses. Compared to controls, the outer retina thinning rate was not significant for all FTD patients (p = 0.34), but was significant for the tauopathy subgroup (-3.9 vs. 0.4 μm/year, p = 0.03). Outer retina thickness change correlated with MMSE change in FTD patients (Spearman rho = 0.60, p = 0.02) and the tauopathy subgroup (rho = 0.73, p = 0.04). CONCLUSION Our finding of FTD outer retina thinning persists and longitudinally correlates with disease progression. These findings were especially seen in probable tauopathy patients, which showed progressive outer retina thinning.
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Affiliation(s)
- Benjamin J. Kim
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Murray Grossman
- Department of Neurology, Frontotemporal Lobar Degeneration Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Delu Song
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Samantha Saludades
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Wei Pan
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Sophia Dominguez-Perez
- Department of Neurology, Frontotemporal Lobar Degeneration Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Joshua L. Dunaief
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Tomas S. Aleman
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Gui-Shuang Ying
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - David J. Irwin
- Department of Neurology, Frontotemporal Lobar Degeneration Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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Kuwako KI, Okano H. Versatile Roles of LKB1 Kinase Signaling in Neural Development and Homeostasis. Front Mol Neurosci 2018; 11:354. [PMID: 30333724 PMCID: PMC6176002 DOI: 10.3389/fnmol.2018.00354] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/11/2018] [Indexed: 01/01/2023] Open
Abstract
Kinase signaling pathways orchestrate a majority of cellular structures and functions across species. Liver kinase B1 (LKB1, also known as STK11 or Par-4) is a ubiquitously expressed master serine/threonine kinase that plays crucial roles in numerous cellular events, such as polarity control, proliferation, differentiation and energy homeostasis, in many types of cells by activating downstream kinases of the AMP-activated protein kinase (AMPK) subfamily members. In contrast to the accumulating evidence for LKB1 functions in nonneuronal tissues, its functions in the nervous system have been relatively less understood until recently. In the brain, LKB1 initially emerged as a principal regulator of axon/dendrite polarity in forebrain neurons. Thereafter, recent investigations have rapidly uncovered diverse and essential functions of LKB1 in the developing and mature nervous system, such as migration, neurite morphogenesis, myelination and the maintenance of neural integrity, demonstrating that LKB1 is also a multifunctional master kinase in the nervous system. In this review article, we summarize the expanding knowledge about the functional aspects of LKB1 signaling in neural development and homeostasis.
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Affiliation(s)
- Ken-Ichiro Kuwako
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
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McLaughlin T, Falkowski M, Park JW, Keegan S, Elliott M, Wang JJ, Zhang SX. Loss of XBP1 accelerates age-related decline in retinal function and neurodegeneration. Mol Neurodegener 2018; 13:16. [PMID: 29615095 PMCID: PMC5883257 DOI: 10.1186/s13024-018-0250-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 01/17/2018] [Indexed: 12/26/2022] Open
Abstract
Background Aging is the strongest risk factor for neurodegenerative diseases and extended age results in neuronal degeneration and functional decline in the visual system. Among many contributing factors to age-related deterioration of neurons is an insufficient activation of the Unfolded Protein Response (UPR) in the endoplasmic reticulum (ER) in response to cellular stress. X-box binding protein 1 (XBP1) is a major component of the UPR and is essential for maintaining protein homeostasis and reducing cellular stresses. Herein, we investigate the role of XBP1 in maintaining morphological and functional integrity in retinal neurons during adulthood and the early stages of aging. Methods The basal and induced levels of XBP1 activation in the retina were measured in young adult and aged mice. Conditional knockout (cKO) of XBP1 in retinal neurons was achieved by crossing XBP1 floxed mice with a retina specific Cre-recombinase line (Chx10-Cre). Retinal morphology, neuronal populations including photoreceptors, bipolar cells, and retinal ganglion cells (RGCs), synaptic structure, and microglial activation were examined with immunohistochemistry and staining of retinal sections. Retinal function was evaluated with light-adapted (photopic) and dark adapted (scotopic) electroretinograms. Retinal mitochondrial function and metabolism was assessed by Seahorse XFe24 Extracellular Flux Analyzer. Results The retinas of aged wild type (WT) mice display a significantly reduced basal level of Xbp1s and compromised activation of ER stress response. In XBP1 cKO mice, significant structural degeneration of the retina, evidenced by thinning of retinal layers and a loss of RGCs, and functional defects indicated by diminished photopic and scotopic ERG b-waves are observed at the age of 12–14 months. Furthermore, discontinuous and disorganized synaptic laminae, colocalized with activated microglia, in the inner plexiform layer is found in the XBP1 cKO retinas. In addition, cKO mice demonstrate a significant increase in ectopic synapses between bipolar cells and photoreceptors, which is strikingly similar to WT mice at 20–24 months of age. These changes are associated with defective retinal glycolysis while mitochondrial respiratory function appears normal in the cKO retina. Conclusions XBP1 cKO mice at 12–14 months of age show significant structural, functional, and metabolic deficits that closely resemble WT mice twice that age. Our findings suggest that the absence of XBP1, a critical component of the UPR, accelerates age-related retinal neurodegeneration. Electronic supplementary material The online version of this article (10.1186/s13024-018-0250-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Todd McLaughlin
- Departments of Ophthalmology and Biochemistry, Ross Eye Institute, University at Buffalo, State University of New York, 3435 Main Street, Buffalo, NY, 14214, USA.,SUNY Eye Institute, State University of New York, Buffalo, NY, USA
| | - Marek Falkowski
- Departments of Ophthalmology and Biochemistry, Ross Eye Institute, University at Buffalo, State University of New York, 3435 Main Street, Buffalo, NY, 14214, USA
| | - Jae Whan Park
- Departments of Ophthalmology and Biochemistry, Ross Eye Institute, University at Buffalo, State University of New York, 3435 Main Street, Buffalo, NY, 14214, USA
| | - Stephen Keegan
- Departments of Ophthalmology and Biochemistry, Ross Eye Institute, University at Buffalo, State University of New York, 3435 Main Street, Buffalo, NY, 14214, USA
| | - Michael Elliott
- Departments of Ophthalmology and Physiology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Joshua J Wang
- Departments of Ophthalmology and Biochemistry, Ross Eye Institute, University at Buffalo, State University of New York, 3435 Main Street, Buffalo, NY, 14214, USA.,SUNY Eye Institute, State University of New York, Buffalo, NY, USA
| | - Sarah X Zhang
- Departments of Ophthalmology and Biochemistry, Ross Eye Institute, University at Buffalo, State University of New York, 3435 Main Street, Buffalo, NY, 14214, USA. .,SUNY Eye Institute, State University of New York, Buffalo, NY, USA.
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Petralia RS, Wang YX, Mattson MP, Yao PJ. Invaginating Presynaptic Terminals in Neuromuscular Junctions, Photoreceptor Terminals, and Other Synapses of Animals. Neuromolecular Med 2017; 19:193-240. [PMID: 28612182 PMCID: PMC6518423 DOI: 10.1007/s12017-017-8445-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 06/01/2017] [Indexed: 10/19/2022]
Abstract
Typically, presynaptic terminals form a synapse directly on the surface of postsynaptic processes such as dendrite shafts and spines. However, some presynaptic terminals invaginate-entirely or partially-into postsynaptic processes. We survey these invaginating presynaptic terminals in all animals and describe several examples from the central nervous system, including giant fiber systems in invertebrates, and cup-shaped spines, electroreceptor synapses, and some specialized auditory and vestibular nerve terminals in vertebrates. We then examine mechanoreceptors and photoreceptors, concentrating on the complex of pre- and postsynaptic processes found in basal invaginations of the cell. We discuss in detail the role of vertebrate invaginating horizontal cell processes in both chemical and electrical feedback mechanisms. We also discuss the common presence of indenting or invaginating terminals in neuromuscular junctions on muscles of most kinds of animals, and especially discuss those of Drosophila and vertebrates. Finally, we consider broad questions about the advantages of possessing invaginating presynaptic terminals and describe some effects of aging and disease, especially on neuromuscular junctions. We suggest that the invagination is a mechanism that can enhance both chemical and electrical interactions at the synapse.
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Affiliation(s)
- Ronald S Petralia
- Advanced Imaging Core, NIDCD/NIH, 35A Center Drive, Room 1E614, Bethesda, MD, 20892-3729, USA.
| | - Ya-Xian Wang
- Advanced Imaging Core, NIDCD/NIH, 35A Center Drive, Room 1E614, Bethesda, MD, 20892-3729, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, NIA/NIH, Baltimore, MD, 21224, USA
| | - Pamela J Yao
- Laboratory of Neurosciences, NIA/NIH, Baltimore, MD, 21224, USA
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37
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Tian DC, Su L, Fan M, Yang J, Zhang R, Wen P, Han Y, Yu C, Zhang C, Ren H, Shi K, Zhu Z, Dong Y, Liu Y, Shi FD. Bidirectional degeneration in the visual pathway in neuromyelitis optica spectrum disorder (NMOSD). Mult Scler 2017; 24:1585-1593. [PMID: 28823217 DOI: 10.1177/1352458517727604] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE This study aims to investigate whether bidirectional degeneration occurs within the visual pathway and, if so, the extent of such changes in neuromyelitis optica spectrum disorder (NMOSD). METHODS In total, 36 NMOSD and 24 healthy controls (HCs) were enrolled. Three-dimensional T1-weighted magnetic resonance imaging (MRI) and diffusion tensor imaging were used to analyze damage to the posterior visual pathway. Damage to the anterior visual pathway was measured by optical coherence tomography. RESULTS In total, 24 NMOSD with prior optic neuritis (NMOON) patients showed significant reduction of peripapillary retinal nerve fiber layer, inner and outer retinal thickness, lateral geniculate nucleus volume, primary visual cortex volume, and decreased integrity of optic radiations, compared with 12 NMOSD without prior optic neuritis (NMONON) patients and 24 HCs. In NMONON, only the inner retinal thickness and the integrity of optic radiations were significantly reduced in comparison with HCs. Moreover, patients with optic neuritis showed severe bidirectional degeneration, the loss of the RNFL was greater than the atrophy of V1. CONCLUSION Our study indicated the presence of trans-synaptic degeneration in NMOSD. Damage to the inner retina and optic radiations can be observed even in NMONON. After an episode of optic neuritis, the anterior visual pathway damage is greater than the posterior visual pathway damage.
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Affiliation(s)
- De-Cai Tian
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Lei Su
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Moli Fan
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Jian Yang
- Department of Radiology, Tianjin Third Central Hospital, Tianjin, China
| | - Rui Zhang
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Peng Wen
- Department of Radiology, Tianjin Third Central Hospital, Tianjin, China
| | - Yujuan Han
- Department of Radiology, Tianjin Third Central Hospital, Tianjin, China
| | - Changlu Yu
- Department of Radiology, Tianjin Third Central Hospital, Tianjin, China
| | - Chao Zhang
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Honglei Ren
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Kaibin Shi
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Zilong Zhu
- Department of Neurology, Tianjin Huanhu Hospital, Tianjin, China
| | - Yinhua Dong
- Department of Neurology, Tianjin Forth Central Hospital, Tianjin, China
| | - Yaou Liu
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Fu-Dong Shi
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin, China/Department of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
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Vijayan V, Verstreken P. Autophagy in the presynaptic compartment in health and disease. J Cell Biol 2017; 216:1895-1906. [PMID: 28515275 PMCID: PMC5496617 DOI: 10.1083/jcb.201611113] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/30/2017] [Accepted: 04/25/2017] [Indexed: 12/25/2022] Open
Abstract
Vijayan and Verstreken review the process of autophagy in the synapse and the role of autophagy in maintaining neuronal function. Synapses are functionally distinct neuronal compartments that are critical for brain function, with synaptic dysfunction being an early pathological feature in aging and disease. Given the large number of proteins needed for synaptic function, the proliferation of defective proteins and the subsequent loss of protein homeostasis may be a leading cause of synaptic dysfunction. Autophagic mechanisms are cellular digestion processes that recycle cellular components and contribute to protein homeostasis. Autophagy is important within the nervous system, but its function in specific compartments such as the synapse has been unclear. Evidence from research on both autophagy and synaptic function suggests that there are links between the two and that synaptic homeostasis during aging requires autophagy to regulate protein homeostasis. Exciting new work on autophagy-modulating proteins that are enriched at the synapse has begun to link autophagy to synapses and synaptic dysfunction in disease. A better understanding of these links will help us harness the potential therapeutic benefits of autophagy in combating age-related disorders of the nervous system.
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Affiliation(s)
- Vinoy Vijayan
- Department of Neurosciences, Katholieke University Leuven, 3000 Leuven, Belgium .,Leuven Institute for Neurodegenerative Disease, Katholieke University Leuven, 3000 Leuven, Belgium.,VIB Center for Brain and Disease Research, 3000 Leuven, Belgium
| | - Patrik Verstreken
- Department of Neurosciences, Katholieke University Leuven, 3000 Leuven, Belgium.,Leuven Institute for Neurodegenerative Disease, Katholieke University Leuven, 3000 Leuven, Belgium.,VIB Center for Brain and Disease Research, 3000 Leuven, Belgium
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Kovács-Valasek A, Szabadfi K, Dénes V, Szalontai B, Tamás A, Kiss P, Szabó A, Setalo G, Reglődi D, Gábriel R. Accelerated retinal aging in PACAP knock-out mice. Neuroscience 2017; 348:1-10. [PMID: 28215987 DOI: 10.1016/j.neuroscience.2017.02.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/31/2017] [Accepted: 02/02/2017] [Indexed: 12/26/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a neurotrophic and neuroprotective peptide. PACAP and its receptors are widely distributed in the retina. A number of reports provided evidence that PACAP is neuroprotective in retinal degenerations. The current study compared retina cell type-specific differences in young (3-4months) and aged adults (14-16months), of wild-type (WT) mice and knock-out (KO) mice lacking endogenous PACAP production during the course of aging. Histological, immunocytochemical and Western blot examinations were performed. The staining for standard neurochemical markers (tyrosine hydroxylase for dopaminergic cells, calbindin 28 kDa for horizontal cells, protein kinase Cα for rod bipolar cells) of young adult PACAP KO retinas showed no substantial alterations compared to young adult WT retinas, except for the specific PACAP receptor (PAC1-R) staining. We could not detect PAC1-R immunoreactivity in bipolar and horizontal cells in young adult PACAP KO animals. Some other age-related changes were observed only in the PACAP KO mice only. These alterations included horizontal and rod bipolar cell dendritic sprouting into the photoreceptor layer and decreased ganglion cell number. Also, Müller glial cells showed elevated GFAP expression compared to the aging WT retinas. Furthermore, Western blot analyses revealed significant differences between the phosphorylation state of ERK1/2 and JNK in KO mice, indicating alterations in the MAPK signaling pathway. These results support the conclusion that endogenous PACAP contributes to protection against aging of the nervous system.
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Affiliation(s)
- Andrea Kovács-Valasek
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary; Department of János Szentágothai Research Center, University of Pécs, Pécs, Hungary
| | - Krisztina Szabadfi
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary
| | - Viktória Dénes
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary
| | - Bálint Szalontai
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary
| | - Andrea Tamás
- Department of Anatomy, University of Pécs, Pécs, Hungary
| | - Péter Kiss
- Department of Anatomy, University of Pécs, Pécs, Hungary
| | - Aliz Szabó
- Department of Biochemistry and Medicinal Chemistry, University of Pécs, Pécs, Hungary
| | - Gyorgy Setalo
- Department of Medical Biology, University of Pécs, Pécs, Hungary; Department of János Szentágothai Research Center, University of Pécs, Pécs, Hungary
| | - Dóra Reglődi
- Department of Anatomy, University of Pécs, Pécs, Hungary
| | - Robert Gábriel
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary; Department of János Szentágothai Research Center, University of Pécs, Pécs, Hungary.
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Lee WH, Higuchi H, Ikeda S, Macke EL, Takimoto T, Pattnaik BR, Liu C, Chu LF, Siepka SM, Krentz KJ, Rubinstein CD, Kalejta RF, Thomson JA, Mullins RF, Takahashi JS, Pinto LH, Ikeda A. Mouse Tmem135 mutation reveals a mechanism involving mitochondrial dynamics that leads to age-dependent retinal pathologies. eLife 2016; 5:e19264. [PMID: 27863209 PMCID: PMC5117855 DOI: 10.7554/elife.19264] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 10/25/2016] [Indexed: 12/21/2022] Open
Abstract
While the aging process is central to the pathogenesis of age-dependent diseases, it is poorly understood at the molecular level. We identified a mouse mutant with accelerated aging in the retina as well as pathologies observed in age-dependent retinal diseases, suggesting that the responsible gene regulates retinal aging, and its impairment results in age-dependent disease. We determined that a mutation in the transmembrane 135 (Tmem135) is responsible for these phenotypes. We observed localization of TMEM135 on mitochondria, and imbalance of mitochondrial fission and fusion in mutant Tmem135 as well as Tmem135 overexpressing cells, indicating that TMEM135 is involved in the regulation of mitochondrial dynamics. Additionally, mutant retina showed higher sensitivity to oxidative stress. These results suggest that the regulation of mitochondrial dynamics through TMEM135 is critical for protection from environmental stress and controlling the progression of retinal aging. Our study identified TMEM135 as a critical link between aging and age-dependent diseases.
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Affiliation(s)
- Wei-Hua Lee
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, United States
| | - Hitoshi Higuchi
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, United States
| | - Sakae Ikeda
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, United States
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, United States
| | - Erica L Macke
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, United States
| | - Tetsuya Takimoto
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, United States
| | - Bikash R Pattnaik
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, United States
- Department of Pediatrics, University of Wisconsin-Madison, Madison, United States
| | - Che Liu
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, United States
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, United States
| | - Li-Fang Chu
- Morgridge Institute for Research, Madison, United States
| | - Sandra M Siepka
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Kathleen J Krentz
- Transgenic Mouse Facility, Biotechnology Center, University of Wisconsin-Madison, Madison, United States
| | - C Dustin Rubinstein
- Translational Genomics Facility, Biotechnology Center, University of Wisconsin-Madison, Madison, United States
| | - Robert F Kalejta
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, United States
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, United States
| | | | - Robert F Mullins
- Department of Ophthalmology and Visual, University of Iowa, Iowa City, United States
| | - Joseph S Takahashi
- Department of Neuroscience, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, United States
| | - Lawrence H Pinto
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Akihiro Ikeda
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, United States
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, United States
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Tillman MA, Panorgias A, Werner JS. Age-related change in fast adaptation mechanisms measured with the scotopic full-field ERG. Doc Ophthalmol 2016; 132:201-12. [PMID: 27126339 PMCID: PMC5356483 DOI: 10.1007/s10633-016-9541-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 04/13/2016] [Indexed: 11/27/2022]
Abstract
PURPOSE To quantify the response dynamics of fast adaptation mechanisms of the scotopic ERG in younger and older adults using full-field m-sequence flash stimulation. METHODS Scotopic ERGs were measured for a series of flashes separated by 65 ms over a range of 260 ms in 16 younger (20-26, 22.2 ± 2.1; range mean ±1 SD) and 16 older (65-85, 71.2 ± 7) observers without retinal pathology. A short-wavelength (λ peak = 442 nm) LED was used for scotopic stimulation, and the flashes ranged from 0.0001 to 0.01 cd s m(-2). The complete binary kernel series was derived from the responses to the m-sequence flash stimulation, and the first- and second-order kernel responses were analyzed. The first-order kernel represented the response to a single, isolated flash, while the second-order kernels reflected the adapted flash responses that followed a single flash by one or more base intervals. B-wave amplitudes of the adapted flash responses were measured and plotted as a function of interstimulus interval to describe the recovery of the scotopic ERG. A linear function was fitted to the linear portion of the recovery curve, and the slope of the line was used to estimate the rate of fast adaptation recovery. RESULTS The amplitudes of the isolated flash responses and rates of scotopic fast adaptation recovery were compared between the younger and older participants using a two-way ANOVA. The isolated flash responses and rates of recovery were found to be significantly lower in the older adults. However, there was no difference between the two age groups in response amplitude or recovery rate after correcting for age-related changes in the density of the ocular media. CONCLUSIONS These results demonstrated that the rate of scotopic fast adaptation recovery of normal younger and older adults is similar when stimuli are equated for retinal illuminance.
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Affiliation(s)
- Megan A Tillman
- Department of Ophthalmology and Vision Science, University of California, Davis, Davis, CA, USA.
| | - Athanasios Panorgias
- Department of Ophthalmology and Vision Science, University of California, Davis, Davis, CA, USA
- Department of Vision Science, New England College of Optometry, Boston, MA, USA
| | - John S Werner
- Department of Ophthalmology and Vision Science, University of California, Davis, Davis, CA, USA
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, CA, USA
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Li S, Mitchell J, Briggs DJ, Young JK, Long SS, Fuerst PG. Morphological Diversity of the Rod Spherule: A Study of Serially Reconstructed Electron Micrographs. PLoS One 2016; 11:e0150024. [PMID: 26930660 PMCID: PMC4773090 DOI: 10.1371/journal.pone.0150024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 02/08/2016] [Indexed: 11/25/2022] Open
Abstract
Purpose Rod spherules are the site of the first synaptic contact in the retina’s rod pathway, linking rods to horizontal and bipolar cells. Rod spherules have been described and characterized through electron micrograph (EM) and other studies, but their morphological diversity related to retinal circuitry and their intracellular structures have not been quantified. Most rod spherules are connected to their soma by an axon, but spherules of rods on the surface of the Mus musculus outer plexiform layer often lack an axon and have a spherule structure that is morphologically distinct from rod spherules connected to their soma by an axon. Retraction of the rod axon and spherule is often observed in disease processes and aging, and the retracted rod spherule superficially resembles rod spherules lacking an axon. We hypothesized that retracted spherules take on an axonless spherule morphology, which may be easier to maintain in a diseased state. To test our hypothesis, we quantified the spatial organization and subcellular structures of rod spherules with and without axons. We then compared them to the retracted spherules in a disease model, mice that overexpress Dscam (Down syndrome cell adhesion molecule), to gain a better understanding of the rod synapse in health and disease. Methods We reconstructed serial EM images of wild type and DscamGoF (gain of function) rod spherules at a resolution of 7 nm in the X-Y axis and 60 nm in the Z axis. Rod spherules with and without axons, and retracted spherules in the DscamGoF retina, were reconstructed. The rod spherule intracellular organelles, the invaginating dendrites of rod bipolar cells and horizontal cell axon tips were also reconstructed for statistical analysis. Results Stereotypical rod (R1) spherules occupy the outer two-thirds of the outer plexiform layer (OPL), where they present as spherical terminals with large mitochondria. This spherule group is highly uniform and composed more than 90% of the rod spherule population. Rod spherules lacking an axon (R2) were also described and characterized. This rod spherule group consists of a specific spatial organization that is strictly located at the apical OPL-facing layer of the Outer Nuclear Layer (ONL). The R2 spherule displays a large bowl-shaped synaptic terminal that hugs the rod soma. Retracted spherules in the DscamGoF retina were also reconstructed to test if they are structurally similar to R2 spherules. The misplaced rod spherules in DscamGoF have a gross morphology that is similar to R2 spherules but have significant disruption in internal synapse organization. Conclusion We described a morphological diversity within Mus musculus rod spherules. This diversity is correlated with rod location in the ONL and contributes to the intracellular differences within spherules. Analysis of the DscamGoF retina indicated that their R2 spherules are not significantly different than wild type R2 spherules, but that their retracted rod spherules have abnormal synaptic organization.
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Affiliation(s)
- Shuai Li
- University of Idaho, Department of Biological Sciences, Moscow, Idaho, 83844, United States of America
| | - Joe Mitchell
- North Idaho College, Natural Sciences Division, Coeur d’Alene, Idaho, 83814, United States of America
| | - Deidrie J. Briggs
- University of Idaho, Department of Biological Sciences, Moscow, Idaho, 83844, United States of America
| | - Jaime K. Young
- University of Idaho, Department of Biological Sciences, Moscow, Idaho, 83844, United States of America
| | - Samuel S. Long
- Lewis-Clark State College, Department of Computer Sciences, Lewiston, Idaho, 83501, United States of America
| | - Peter G. Fuerst
- University of Idaho, Department of Biological Sciences, Moscow, Idaho, 83844, United States of America
- WWAMI Medical Education Program, Moscow, Idaho, 83844, United States of America
- * E-mail:
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Transplantation of human embryonic stem cell-derived retinal tissue in two primate models of retinal degeneration. Proc Natl Acad Sci U S A 2015; 113:E81-90. [PMID: 26699487 DOI: 10.1073/pnas.1512590113] [Citation(s) in RCA: 214] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Retinal transplantation therapy for retinitis pigmentosa is increasingly of interest due to accumulating evidence of transplantation efficacy from animal studies and development of techniques for the differentiation of human embryonic stem cells (hESCs) and induced pluripotent stem cells into retinal tissues or cells. In this study, we aimed to assess the potential clinical utility of hESC-derived retinal tissues (hESC-retina) using newly developed primate models of retinal degeneration to obtain preparatory information regarding the potential clinical utility of these hESC-retinas in transplantation therapy. hESC-retinas were first transplanted subretinally into nude rats with or without retinal degeneration to confirm their competency as a graft to mature to form highly specified outer segment structure and to integrate after transplantation. Two focal selective photoreceptor degeneration models were then developed in monkeys by subretinal injection of cobalt chloride or 577-nm optically pumped semiconductor laser photocoagulation. The utility of the developed models and a practicality of visual acuity test developed for monkeys were evaluated. Finally, feasibility of hESC-retina transplantation was assessed in the developed monkey models under practical surgical procedure and postoperational examinations. Grafted hESC-retina was observed differentiating into a range of retinal cell types, including rod and cone photoreceptors that developed structured outer nuclear layers after transplantation. Further, immunohistochemical analyses suggested the formation of host-graft synaptic connections. The findings of this study demonstrate the clinical feasibility of hESC-retina transplantation and provide the practical tools for the optimization of transplantation strategies for future clinical applications.
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DSCAM promotes refinement in the mouse retina through cell death and restriction of exploring dendrites. J Neurosci 2015; 35:5640-54. [PMID: 25855178 DOI: 10.1523/jneurosci.2202-14.2015] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In this study we develop and use a gain-of-function mouse allele of the Down syndrome cell adhesion molecule (Dscam) to complement loss-of-function models. We assay the role of Dscam in promoting cell death, spacing, and laminar targeting of neurons in the developing mouse retina. We find that ectopic or overexpression of Dscam is sufficient to drive cell death. Gain-of-function studies indicate that Dscam is not sufficient to increase spatial organization, prevent cell-to-cell pairing, or promote active avoidance in the mouse retina, despite the similarity of the Dscam loss-of-function phenotype in the mouse retina to phenotypes observed in Drosophila Dscam1 mutants. Both gain- and loss-of-function studies support a role for Dscam in targeting neurites; DSCAM is necessary for precise dendrite lamination, and is sufficient to retarget neurites of outer retinal cells after ectopic expression. We further demonstrate that DSCAM guides dendrite targeting in type 2 dopaminergic amacrine cells, by restricting the stratum in which exploring retinal dendrites stabilize, in a Dscam dosage-dependent manner. Based on these results we propose a single model to account for the numerous Dscam gain- and loss-of-function phenotypes reported in the mouse retina whereby DSCAM eliminates inappropriately placed cells and connections.
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Szabadfi K, Estrada C, Fernandez-Villalba E, Tarragon E, Setalo G, Izura V, Reglodi D, Tamas A, Gabriel R, Herrero MT. Retinal aging in the diurnal Chilean rodent (Octodon degus): histological, ultrastructural and neurochemical alterations of the vertical information processing pathway. Front Cell Neurosci 2015; 9:126. [PMID: 25954153 PMCID: PMC4405622 DOI: 10.3389/fncel.2015.00126] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 03/17/2015] [Indexed: 12/25/2022] Open
Abstract
The retina is sensitive to age-dependent degeneration. To find suitable animal models to understand and map this process has particular importance. The degu (Octodon degus) is a diurnal rodent with dichromatic color vision. Its retinal structure is similar to that in humans in many respects, therefore, it is well suited to study retinal aging. Histological, cell type-specific and ultrastructural alterations were examined in 6-, 12- and 36-months old degus. The characteristic layers of the retina were present at all ages, but slightly loosened tissue structure could be observed in 36-month-old animals both at light and electron microscopic levels. Elevated Glial fibrillary acidic protein (GFAP) expression was observed in Müller glial cells in aging retinas. The number of rod bipolar cells and the ganglion cells was reduced in the aging specimens, while that of cone bipolar cells remained unchanged. Other age-related differences were detected at ultrastructural level: alteration of the retinal pigment epithelium and degenerated photoreceptor cells were evident. Ribbon synapses were sparse and often differed in morphology from those in the young animals. These results support our hypothesis that (i) the rod pathway seems to be more sensitive than the cone pathway to age-related cell loss; (ii) structural changes in the basement membrane of pigment epithelial cells can be one of the early signs of degenerative processes; (iii) the loss of synaptic proteins especially from those of the ribbon synapses are characteristic; and (iv) the degu retina may be a suitable model for studying retinal aging.
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Affiliation(s)
- Krisztina Szabadfi
- Department of Experimental Zoology and Neurobiology, University of Pecs Pecs, Hungary ; Janos Szentagothai Research Center Pecs, Hungary
| | - Cristina Estrada
- Clinical and Experimental Neuroscience (NiCE), CIBERNED and Institute of Bio-Health Research of Murcia (IMIB), School of Medicine, Campus Mare Nostrum, University of Murcia Murcia, Spain
| | - Emiliano Fernandez-Villalba
- Clinical and Experimental Neuroscience (NiCE), CIBERNED and Institute of Bio-Health Research of Murcia (IMIB), School of Medicine, Campus Mare Nostrum, University of Murcia Murcia, Spain
| | - Ernesto Tarragon
- Clinical and Experimental Neuroscience (NiCE), CIBERNED and Institute of Bio-Health Research of Murcia (IMIB), School of Medicine, Campus Mare Nostrum, University of Murcia Murcia, Spain
| | - Gyorgy Setalo
- Department of Medical Biology, University of Pecs Pecs, Hungary
| | - Virginia Izura
- Clinical and Experimental Neuroscience (NiCE), CIBERNED and Institute of Bio-Health Research of Murcia (IMIB), School of Medicine, Campus Mare Nostrum, University of Murcia Murcia, Spain
| | - Dora Reglodi
- Department of Anatomy, MTA-PTE "Lendulet" PACAP Research Team, University of Pecs Pecs, Hungary
| | - Andrea Tamas
- Department of Anatomy, MTA-PTE "Lendulet" PACAP Research Team, University of Pecs Pecs, Hungary
| | - Robert Gabriel
- Department of Experimental Zoology and Neurobiology, University of Pecs Pecs, Hungary ; Janos Szentagothai Research Center Pecs, Hungary
| | - Maria Trinidad Herrero
- Clinical and Experimental Neuroscience (NiCE), CIBERNED and Institute of Bio-Health Research of Murcia (IMIB), School of Medicine, Campus Mare Nostrum, University of Murcia Murcia, Spain
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Sanuki R, Watanabe S, Sugita Y, Irie S, Kozuka T, Shimada M, Ueno S, Usukura J, Furukawa T. Protein-4.1G-Mediated Membrane Trafficking Is Essential for Correct Rod Synaptic Location in the Retina and for Normal Visual Function. Cell Rep 2015; 10:796-808. [DOI: 10.1016/j.celrep.2015.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 11/17/2014] [Accepted: 12/24/2014] [Indexed: 11/27/2022] Open
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Knoflach D, Schicker K, Glösmann M, Koschak A. Gain-of-function nature of Cav1.4 L-type calcium channels alters firing properties of mouse retinal ganglion cells. Channels (Austin) 2015; 9:298-306. [PMID: 26274509 PMCID: PMC4826138 DOI: 10.1080/19336950.2015.1078040] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/22/2015] [Accepted: 07/22/2015] [Indexed: 10/25/2022] Open
Abstract
Proper function of Cav1.4 L-type calcium channels is crucial for neurotransmitter release in the retina. Our understanding about how different levels of Cav1.4 channel activity affect retinal function is still limited. In the gain-of-function mouse model Cav1.4-IT we expected a reduction in the photoreceptor dynamic range but still transmission toward retinal ganglion cells. A fraction of Cav1.4-IT ganglion cells responded to light stimulation in multielectrode array recordings from whole-mounted retinas, but showed a significantly delayed response onset. Another significant number of cells showed higher activity in darkness. In addition to structural remodeling observed at the first retinal synapse of Cav1.4-IT mice the functional data suggested a loss of contrast enhancement, a fundamental feature of our visual system. In fact, Cav1.4-IT mouse retinas showed a decline in spatial response and changes in their contrast sensitivity profile. Photoreceptor degeneration was obvious from the nodular structure of cone axons and enlarged pedicles which partly moved toward the outer nuclear layer. Loss of photoreceptors was also expressed as reduced expression of proteins involved in chemical and electrical transmission, as such metabotropic glutamate receptor mGluR6 and the gap junction protein Connexin 36. Such gross changes in retinal structure and function could also explain the diminished visual performance of CSNB2 patients. The expression pattern of the plasma-membrane calcium ATPase 1 which participates in the maintenance of the intracellular calcium homeostasis in photoreceptors was changed in Cav1.4-IT mice. This might be part of a protection mechanism against increased calcium influx, as this is suggested for Cav1.4-IT channels.
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Affiliation(s)
- Dagmar Knoflach
- Medical University Vienna, Center for Physiology and Pharmacology; Department of Neurophysiology and -pharmacology; Vienna, Austria
| | - Klaus Schicker
- Medical University Vienna, Center for Physiology and Pharmacology; Department of Neurophysiology and -pharmacology; Vienna, Austria
| | | | - Alexandra Koschak
- Medical University Vienna, Center for Physiology and Pharmacology; Department of Neurophysiology and -pharmacology; Vienna, Austria
- University of Innsbruck, Institute of Pharmacy, Pharmacology and Toxicology; Innsbruck, Austria
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Wong VH, Armitage JA, He Z, Hui F, Vingrys AJ, Bui BV. Chronic intraocular pressure elevation impairs autoregulatory capacity in streptozotocin-induced diabetic rat retina. Ophthalmic Physiol Opt 2014; 35:125-34. [PMID: 25529024 DOI: 10.1111/opo.12174] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 10/23/2014] [Indexed: 02/03/2023]
Abstract
PURPOSE To assess ocular blood flow responses to acute IOP stress following 4 weeks of chronic IOP elevation in streptozotocin (STZ)-induced diabetic and control rats. We hypothesise that chronic IOP elevation for 4 weeks will further impair blood flow regulation in STZ-induced diabetic rats eyes. METHODS Two weeks following citrate buffer or STZ-injections chronic IOP elevation was induced in Long Evans rats via fortnightly intracameral injections of microspheres (15 μm) suspended in 5% polyethylene glycol. IOP was monitored daily. Electroretinography (ERG, -6.79-2.07 log cd s m(-2) ) was undertaken at Week 4 to compare photoreceptor (RmPIII ), ON-bipolar cell (Vmax ) and ganglion cell dominant ERG [scotopic threshold response (STR)] components. 4 weeks post-chronic IOP induction, ocular blood flow (laser Doppler flowmetry) was measured in response to acute IOP challenge (10-100 mmHg, in 5 mmHg steps, each 3 min). RESULTS Four weeks of chronic IOP (mean ± S.E.M., citrate: 24.0 ± 0.3 to 30.7 ± 1.3 and STZ-diabetes: 24.2 ± 0.2 to 31.1 ± 1.2 mmHg) was associated with reduced photoreceptor amplitude in both groups (-25.3 ± 2.2% and -17.2 ± 3.0%, respectively). STZ-diabetic eyes showed reduced photoreceptor sensitivity (citrate: 0.5 ± 1.8%, STZ-diabetic: -8.1 ± 2.4%). Paradoxically ON-bipolar cell sensitivity was increased, particularly in citrate control eyes (citrate: 166.8 ± 25.9%, STZ-diabetic: 64.8 ± 18.7%). The ganglion cell dominant STR was not significantly reduced in STZ-diabetic rats. Using acute IOP elevation to probe autoregulation, we show that STZ-diabetes impaired autoregulation compared with citrate control animals. The combination of STZ-diabetes and chronic IOP elevation further impaired autoregulation. CONCLUSIONS STZ-diabetes and chronic IOP elevation appear to be additive risk factors for impairment of ocular blood flow autoregulation.
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Affiliation(s)
- Vickie H Wong
- Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, Australia
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Higuchi H, Macke EL, Lee WH, Miller SA, Xu JC, Ikeda S, Ikeda A. Genetic basis of age-dependent synaptic abnormalities in the retina. Mamm Genome 2014; 26:21-32. [PMID: 25273269 DOI: 10.1007/s00335-014-9546-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 09/01/2014] [Indexed: 12/17/2022]
Abstract
Understanding the normal aging process will help us determine the mechanisms of how age-related diseases are caused and progress. A/J inbred mice have been shown to exhibit accelerated aging phenotypes in the retina including increased inflammation and photoreceptor cell degeneration, which resemble human aging symptoms. C57BL/6J (B6) inbred mice are less susceptible for these abnormalities, indicating the existence of genetic factor(s) that affect their severity. In this study, we determined that another age-dependent phenotype, ectopic synapse formation, is also accelerated in the A/J retina compared to the B6 retina. Through genetic mapping utilizing recombinant inbred strains, we identified quantitative trait loci (QTLs) on chromosome 7 and 19, which contribute to abnormal retinal synapses as well as other age-dependent phenotypes. Using consomic single chromosome substitution lines where a single chromosome is from A/J and the rest of the genome is B6, we investigated the individual effect of each QTL on retinal aging phenotypes. We observed that both QTLs independently contribute to abnormal retinal synapses, reduction in the number of cone cells, and an up-regulation of retinal stress marker, glial fibrillary acidic protein (GFAP). Mice with a single chromosome substitution on chromosome 19 also exhibited an increase in inflammatory cells, which is characteristic of aging and age-related macular degeneration. Thus, we identified QTLs that are independently capable of affecting the severity and progression of age-dependent retinal abnormalities in mice.
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Affiliation(s)
- Hitoshi Higuchi
- Department of Medical Genetics, University of Wisconsin-Madison, Madison, WI, 53706, USA
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Genové G, Mollick T, Johansson K. Photoreceptor degeneration, structural remodeling and glial activation: a morphological study on a genetic mouse model for pericyte deficiency. Neuroscience 2014; 279:269-84. [PMID: 25224828 DOI: 10.1016/j.neuroscience.2014.09.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Revised: 09/01/2014] [Accepted: 09/05/2014] [Indexed: 01/10/2023]
Abstract
Interaction between pericytes and endothelial cells via platelet-derived growth factor B (PDGF-B) signaling is critical for the development of the retinal microvasculature. The PDGF-B retention motif controls the spatial distribution range of the growth factor in the vicinity of its producing endothelial cells allowing its recognition by PDGF receptor beta-(PDGFR-β)-carrying pericytes; this promotes recruitment of pericytes to the vascular basement membrane. Impairment of the PDGF-B signaling mechanism causes development of vascular abnormalities, and in the retina this consequently leads to defects in the neurological circuitry. The vascular pathology in the pdgf-b(ret/ret) (PDGF-B retention motif knockout) mouse retina has been previously reported; our study investigates the progressive neuronal defects and changes in the retinal morphology of this pericyte-deficient mouse model. Immunohistochemical analysis revealed retinal injuries to occur as early as postnatal day (P) 10 with substantial damage progressing from P15 and onward. Vascular abnormalities were apparent from P10, however, prominent neuronal defects were mostly observed from P15, beginning with the compromised integrity of the laminated retinal structure characterized by the presence of rosettes and focally distorted regions. Photoreceptor degeneration was observed by loss of both rod and cone cells, including the disassembly and altered structure of their synaptic terminals. Significant shortening of cone outer segments was observed from P10 and later stages; however, decrease in cone density was only observed at P28. Disorganization and dendrite remodeling of rod bipolar cells also added to the diminished neural and synaptic integrity. Moreover, in response to retinal injuries, Müller and microglial cells were observed to be in the reactive phenotype from P15 and onward. Such a sequence of events indicates that the pdgf-b(ret/ret) mouse model displays a short time frame between P10 and P15, during which the retina shifts to a retinopathic phase by the development of prominently altered morphological features.
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Affiliation(s)
- G Genové
- Division of Vascular Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - T Mollick
- School of Health and Medicine, Örebro University, Örebro, Sweden
| | - K Johansson
- School of Health and Medicine, Örebro University, Örebro, Sweden.
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