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Du R, Wang P, Tian N. CD3ζ-Mediated Signaling Protects Retinal Ganglion Cells in Glutamate Excitotoxicity of the Retina. Cells 2024; 13:1006. [PMID: 38920637 PMCID: PMC11201742 DOI: 10.3390/cells13121006] [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: 03/30/2024] [Revised: 05/28/2024] [Accepted: 06/06/2024] [Indexed: 06/27/2024] Open
Abstract
Excessive levels of glutamate activity could potentially damage and kill neurons. Glutamate excitotoxicity is thought to play a critical role in many CNS and retinal diseases. Accordingly, glutamate excitotoxicity has been used as a model to study neuronal diseases. Immune proteins, such as major histocompatibility complex (MHC) class I molecules and their receptors, play important roles in many neuronal diseases, while T-cell receptors (TCR) are the primary receptors of MHCI. We previously showed that a critical component of TCR, CD3ζ, is expressed by mouse retinal ganglion cells (RGCs). The mutation of CD3ζ or MHCI molecules compromises the development of RGC structure and function. In this study, we investigated whether CD3ζ-mediated molecular signaling regulates RGC death in glutamate excitotoxicity. We show that mutation of CD3ζ significantly increased RGC survival in NMDA-induced excitotoxicity. In addition, we found that several downstream molecules of TCR, including Src (proto-oncogene tyrosine-protein kinase) family kinases (SFKs) and spleen tyrosine kinase (Syk), are expressed by RGCs. Selective inhibition of an SFK member, Hck, or Syk members, Syk or Zap70, significantly increased RGC survival in NMDA-induced excitotoxicity. These results provide direct evidence to reveal the underlying molecular mechanisms that control RGC death under disease conditions.
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Affiliation(s)
- Rui Du
- Department of Ophthalmology and Visual Science, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (R.D.); (P.W.)
| | - Ping Wang
- Department of Ophthalmology and Visual Science, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (R.D.); (P.W.)
| | - Ning Tian
- Department of Ophthalmology and Visual Science, University of Utah School of Medicine, Salt Lake City, UT 84132, USA; (R.D.); (P.W.)
- Department of Neurobiology, University of Utah, Salt Lake City, UT 84132, USA
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84132, USA
- Veterans Affairs Medical Center, Salt Lake City, UT 84148, USA
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Grannonico M, Miller DA, Liu M, Krause MA, Savier E, Erisir A, Netland PA, Cang J, Zhang HF, Liu X. Comparative In Vivo Imaging of Retinal Structures in Tree Shrews, Humans, and Mice. eNeuro 2024; 11:ENEURO.0373-23.2024. [PMID: 38538082 PMCID: PMC10972737 DOI: 10.1523/eneuro.0373-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 02/29/2024] [Accepted: 03/07/2024] [Indexed: 04/01/2024] Open
Abstract
Rodent models, such as mice and rats, are commonly used to examine retinal ganglion cell damage in eye diseases. However, as nocturnal animals, rodent retinal structures differ from primates, imposing significant limitations in studying retinal pathology. Tree shrews (Tupaia belangeri) are small, diurnal paraprimates that exhibit superior visual acuity and color vision compared with mice. Like humans, tree shrews have a dense retinal nerve fiber layer (RNFL) and a thick ganglion cell layer (GCL), making them a valuable model for investigating optic neuropathies. In this study, we applied high-resolution visible-light optical coherence tomography to characterize the tree shrew retinal structure in vivo and compare it with that of humans and mice. We quantitatively characterize the tree shrew's retinal layer structure in vivo, specifically examining the sublayer structures within the inner plexiform layer (IPL) for the first time. Next, we conducted a comparative analysis of retinal layer structures among tree shrews, mice, and humans. We then validated our in vivo findings in the tree shrew inner retina using ex vivo confocal microscopy. The in vivo and ex vivo analyses of the shrew retina build the foundation for future work to accurately track and quantify the retinal structural changes in the IPL, GCL, and RNFL during the development and progression of human optic diseases.
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Affiliation(s)
- Marta Grannonico
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
| | - David A Miller
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208
| | - Mingna Liu
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
| | - Michael A Krause
- Departments of Ophthalmology, University of Virginia, Charlottesville, Virginia 22904
| | - Elise Savier
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
| | - Alev Erisir
- Psychology, University of Virginia, Charlottesville, Virginia 22904
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia 22904
| | - Peter A Netland
- Departments of Ophthalmology, University of Virginia, Charlottesville, Virginia 22904
| | - Jianhua Cang
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
- Psychology, University of Virginia, Charlottesville, Virginia 22904
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia 22904
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208
| | - Xiaorong Liu
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904
- Psychology, University of Virginia, Charlottesville, Virginia 22904
- Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia 22904
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3
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Ma D, Deng W, Khera Z, Sajitha TA, Wang X, Wollstein G, Schuman JS, Lee S, Shi H, Ju MJ, Matsubara J, Beg MF, Sarunic M, Sappington RM, Chan KC. Early inner plexiform layer thinning and retinal nerve fiber layer thickening in excitotoxic retinal injury using deep learning-assisted optical coherence tomography. Acta Neuropathol Commun 2024; 12:19. [PMID: 38303097 PMCID: PMC10835918 DOI: 10.1186/s40478-024-01732-z] [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: 11/27/2023] [Accepted: 01/14/2024] [Indexed: 02/03/2024] Open
Abstract
Excitotoxicity from the impairment of glutamate uptake constitutes an important mechanism in neurodegenerative diseases such as Alzheimer's, multiple sclerosis, and Parkinson's disease. Within the eye, excitotoxicity is thought to play a critical role in retinal ganglion cell death in glaucoma, diabetic retinopathy, retinal ischemia, and optic nerve injury, yet how excitotoxic injury impacts different retinal layers is not well understood. Here, we investigated the longitudinal effects of N-methyl-D-aspartate (NMDA)-induced excitotoxic retinal injury in a rat model using deep learning-assisted retinal layer thickness estimation. Before and after unilateral intravitreal NMDA injection in nine adult Long Evans rats, spectral-domain optical coherence tomography (OCT) was used to acquire volumetric retinal images in both eyes over 4 weeks. Ten retinal layers were automatically segmented from the OCT data using our deep learning-based algorithm. Retinal degeneration was evaluated using layer-specific retinal thickness changes at each time point (before, and at 3, 7, and 28 days after NMDA injection). Within the inner retina, our OCT results showed that retinal thinning occurred first in the inner plexiform layer at 3 days after NMDA injection, followed by the inner nuclear layer at 7 days post-injury. In contrast, the retinal nerve fiber layer exhibited an initial thickening 3 days after NMDA injection, followed by normalization and thinning up to 4 weeks post-injury. Our results demonstrated the pathological cascades of NMDA-induced neurotoxicity across different layers of the retina. The early inner plexiform layer thinning suggests early dendritic shrinkage, whereas the initial retinal nerve fiber layer thickening before subsequent normalization and thinning indicates early inflammation before axonal loss and cell death. These findings implicate the inner plexiform layer as an early imaging biomarker of excitotoxic retinal degeneration, whereas caution is warranted when interpreting the ganglion cell complex combining retinal nerve fiber layer, ganglion cell layer, and inner plexiform layer thicknesses in conventional OCT measures. Deep learning-assisted retinal layer segmentation and longitudinal OCT monitoring can help evaluate the different phases of retinal layer damage upon excitotoxicity.
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Affiliation(s)
- Da Ma
- Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, 27157, USA.
- Wake Forest University Health Sciences, Winston-Salem, NC, USA.
- Translational Eye and Vision Research Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada.
| | - Wenyu Deng
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
- Department of Ophthalmology, SUNY Downstate Medical Center, Brooklyn, NY, USA
| | - Zain Khera
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
| | - Thajunnisa A Sajitha
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
| | - Xinlei Wang
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
- Center for Neural Science, College of Arts and Science, New York University, New York, NY, USA
- Department of Biomedical Engineering, Tandon School of Engineering, New York University, Brooklyn, NY, USA
| | - Joel S Schuman
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
- Center for Neural Science, College of Arts and Science, New York University, New York, NY, USA
- Department of Biomedical Engineering, Tandon School of Engineering, New York University, Brooklyn, NY, USA
- Wills Eye Hospital, Philadelphia, PA, USA
- Department of Biomedical Engineering, Drexel University, Philadelphia, PA, USA
- Neuroscience Institute, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
| | - Sieun Lee
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
- Department of Ophthalmology and Visual Sciences, The University of British Columbia, Vancouver, BC, Canada
- Mental Health and Clinical Neurosciences, School of Medicine, University of Nottingham, Nottingham, UK
| | - Haolun Shi
- Department of Statistics and Actuarial Science, Simon Fraser University, Burnaby, BC, Canada
| | - Myeong Jin Ju
- Department of Ophthalmology and Visual Sciences, The University of British Columbia, Vancouver, BC, Canada
| | - Joanne Matsubara
- Department of Ophthalmology and Visual Sciences, The University of British Columbia, Vancouver, BC, Canada
| | - Mirza Faisal Beg
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Marinko Sarunic
- Institute of Ophthalmology, University College London, London, UK
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Rebecca M Sappington
- Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, 27157, USA
- Wake Forest University Health Sciences, Winston-Salem, NC, USA
- Translational Eye and Vision Research Center, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Kevin C Chan
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA.
- Center for Neural Science, College of Arts and Science, New York University, New York, NY, USA.
- Department of Biomedical Engineering, Tandon School of Engineering, New York University, Brooklyn, NY, USA.
- Neuroscience Institute, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA.
- Department of Radiology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA.
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Qian Z, Zheng K, Xu Y, Chen S, Chen S, Liang J, Cao Y, Ng TK, Qiu K. Longitudinal in vivo evaluation of retinal ganglion cell complex layer and dendrites in mice with experimental autoimmune encephalomyelitis. Exp Eye Res 2023; 237:109708. [PMID: 37913917 DOI: 10.1016/j.exer.2023.109708] [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: 09/05/2023] [Revised: 10/24/2023] [Accepted: 10/28/2023] [Indexed: 11/03/2023]
Abstract
Experimental autoimmune encephalomyelitis (EAE), induced by the immunization of myelin oligodendrocyte glycoprotein (MOG), is related to human MOG antibody-associated disease (MOGAD). Neuroinflammation and demyelination of the optic nerve can lead to retinal ganglion cell (RGC) death and axonal damage in MOGAD. Here, we aimed to evaluate the structural changes in RGCs longitudinally by in vivo imaging in mice with RGCs expressing yellow fluorescent protein along the course of EAE. Successful induction of EAE was confirmed by the neurological function scores and histology analyses. The changes in the thickness of ganglion cell complex (GCC) layer and RGC survival and dendrites were monitored longitudinally along the course of EAE. Before the onset of EAE, there were no significant changes in the number and morphology of RGCs and the thickness of the GCC layer as compared to the mice without EAE induction. After the onset of EAE, the thickness of the GCC layer and the RGC number and dendritic network all gradually decreased along the course of EAE. Notably, dendritic shrinkage could be detected earlier than the thinning of the GCC layer. In summary, this study delineated the longitudinal profile of RGC structural changes in EAE mice, providing an assessment platform for monitoring outcomes of RGC treatments.
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Affiliation(s)
- Zhen Qian
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China; Shantou University Medical College, Shantou, Guangdong, China
| | - Ke Zheng
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China; Shantou University Medical College, Shantou, Guangdong, China
| | - Yanxuan Xu
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Si Chen
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Shaowan Chen
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Jiajian Liang
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Yingjie Cao
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China
| | - Tsz Kin Ng
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China; Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong.
| | - Kunliang Qiu
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou, Guangdong, China.
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5
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Soucy JR, Aguzzi EA, Cho J, Gilhooley MJ, Keuthan C, Luo Z, Monavarfeshani A, Saleem MA, Wang XW, Wohlschlegel J, Baranov P, Di Polo A, Fortune B, Gokoffski KK, Goldberg JL, Guido W, Kolodkin AL, Mason CA, Ou Y, Reh TA, Ross AG, Samuels BC, Welsbie D, Zack DJ, Johnson TV. Retinal ganglion cell repopulation for vision restoration in optic neuropathy: a roadmap from the RReSTORe Consortium. Mol Neurodegener 2023; 18:64. [PMID: 37735444 PMCID: PMC10514988 DOI: 10.1186/s13024-023-00655-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 09/07/2023] [Indexed: 09/23/2023] Open
Abstract
Retinal ganglion cell (RGC) death in glaucoma and other optic neuropathies results in irreversible vision loss due to the mammalian central nervous system's limited regenerative capacity. RGC repopulation is a promising therapeutic approach to reverse vision loss from optic neuropathies if the newly introduced neurons can reestablish functional retinal and thalamic circuits. In theory, RGCs might be repopulated through the transplantation of stem cell-derived neurons or via the induction of endogenous transdifferentiation. The RGC Repopulation, Stem Cell Transplantation, and Optic Nerve Regeneration (RReSTORe) Consortium was established to address the challenges associated with the therapeutic repair of the visual pathway in optic neuropathy. In 2022, the RReSTORe Consortium initiated ongoing international collaborative discussions to advance the RGC repopulation field and has identified five critical areas of focus: (1) RGC development and differentiation, (2) Transplantation methods and models, (3) RGC survival, maturation, and host interactions, (4) Inner retinal wiring, and (5) Eye-to-brain connectivity. Here, we discuss the most pertinent questions and challenges that exist on the path to clinical translation and suggest experimental directions to propel this work going forward. Using these five subtopic discussion groups (SDGs) as a framework, we suggest multidisciplinary approaches to restore the diseased visual pathway by leveraging groundbreaking insights from developmental neuroscience, stem cell biology, molecular biology, optical imaging, animal models of optic neuropathy, immunology & immunotolerance, neuropathology & neuroprotection, materials science & biomedical engineering, and regenerative neuroscience. While significant hurdles remain, the RReSTORe Consortium's efforts provide a comprehensive roadmap for advancing the RGC repopulation field and hold potential for transformative progress in restoring vision in patients suffering from optic neuropathies.
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Affiliation(s)
- Jonathan R Soucy
- Department of Ophthalmology, Schepens Eye Research Institute of Mass. Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Erika A Aguzzi
- The Institute of Ophthalmology, University College London, London, England, UK
| | - Julie Cho
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Michael James Gilhooley
- The Institute of Ophthalmology, University College London, London, England, UK
- Moorfields Eye Hospital, London, England, UK
| | - Casey Keuthan
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ziming Luo
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Aboozar Monavarfeshani
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Meher A Saleem
- Bascom Palmer Eye Institute, University of Miami Health System, Miami, FL, USA
| | - Xue-Wei Wang
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Petr Baranov
- Department of Ophthalmology, Schepens Eye Research Institute of Mass. Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Adriana Di Polo
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada
- University of Montreal Hospital Research Centre, Montreal, QC, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, OR, USA
| | - Kimberly K Gokoffski
- Department of Ophthalmology, Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Jeffrey L Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - William Guido
- Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Alex L Kolodkin
- The Solomon H Snyder, Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Carol A Mason
- Departments of Pathology and Cell Biology, Neuroscience, and Ophthalmology, College of Physicians and Surgeons, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Yvonne Ou
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Thomas A Reh
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Ahmara G Ross
- Departments of Ophthalmology and Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Brian C Samuels
- Department of Ophthalmology and Visual Sciences, Callahan Eye Hospital, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Derek Welsbie
- Shiley Eye Institute and Viterbi Family Department of Ophthalmology, University of California, San Diego, CA, USA
| | - Donald J Zack
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, 21287 MD, USA
- Departments of Neuroscience, Molecular Biology & Genetics, and Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Thomas V Johnson
- Departments of Neuroscience, Molecular Biology & Genetics, and Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Cellular & Molecular Medicine Program, Johns Hopkins University School of Medicine, Baltimore, 21287 MD, USA.
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Levin LA, Chiang MF, Dyer MA, Greenwell TN, Svendsen CN, Tumminia SJ, Van Gelder RN, Wong RO. Translational roadmap for regenerative therapies of eye disease. MED 2023; 4:583-590. [PMID: 37689055 PMCID: PMC10793077 DOI: 10.1016/j.medj.2023.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 06/07/2023] [Accepted: 06/12/2023] [Indexed: 09/11/2023]
Abstract
The translation of regenerative therapies to neuronal eye diseases requires a roadmap specific to the nature of the target diseases, patient population, methodologies for assessing outcome, and other factors. This commentary focuses on critical issues for translating regenerative eye therapies relevant to retinal neurons to human clinical trials.
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Affiliation(s)
- Leonard A Levin
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, QC H3A2B4, Canada; Department of Neurology & Neurosurgery, McGill University, Montreal, QC H3A2B4, Canada.
| | - Michael F Chiang
- National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA; National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Michael A Dyer
- Department of Developmental Neurobiology, St. Jude's Research Hospital, Memphis, TN 38105, USA
| | - Thomas N Greenwell
- National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Clive N Svendsen
- Board of Governors Regenerative Medicine Institute, Cedars Sinai Medical Center, Los Angeles, CA 90048, USA; Department of Biomedical Sciences, Cedars Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Santa J Tumminia
- National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Russell N Van Gelder
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98195, USA; Department of Biological Structure, University of Washington School of Medicine, Seattle, WA 98195, USA; Department of Pathology and Laboratory Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA; Roger and Angie Karalis Johnson Retina Center, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Rachel O Wong
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98195, USA; Department of Biological Structure, University of Washington School of Medicine, Seattle, WA 98195, USA
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Soliño M, Yu A, Della Santina L, Ou Y. Large-scale survey of excitatory synapses reveals sublamina-specific and asymmetric synapse disassembly in a neurodegenerative circuit. iScience 2023; 26:107262. [PMID: 37609630 PMCID: PMC10440711 DOI: 10.1016/j.isci.2023.107262] [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: 03/10/2023] [Revised: 05/09/2023] [Accepted: 06/27/2023] [Indexed: 08/24/2023] Open
Abstract
In the nervous system, parallel circuits are organized in part by the lamina-specific compartmentalization of synaptic connections. In sensory systems such as mammalian retina, degenerating third-order neurons remodel their local presynaptic connectivity with second-order neurons. To determine whether there are sublamina-specific perturbations after injury of adult retinal ganglion cells, we comprehensively analyzed excitatory synapses across the inner plexiform layer (IPL) where bipolar cells connect to ganglion cells. Here, we show that pre- and postsynaptic component loss occurs throughout the IPL in a sublamina-dependent fashion after transient intraocular pressure elevation. Partnered synaptic components are lost as neurodegeneration progresses, while unpartnered synaptic components remain stable. Furthermore, presynaptic components are either lost first or simultaneously with the postsynaptic component. Our results demonstrate that this degenerating neural circuit exhibits differential vulnerability of excitatory synapses depending on IPL depth, highlighting the ordered disassembly of synapses that is specific to laminar compartments of the retina.
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Affiliation(s)
- Manuel Soliño
- Department of Ophthalmology, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA
| | - Alfred Yu
- Department of Ophthalmology, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA
| | - Luca Della Santina
- Department of Ophthalmology, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA
- College of Optometry, University of Houston, Houston, TX 77204, USA
| | - Yvonne Ou
- Department of Ophthalmology, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA
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8
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Dunn M, Cull G, Reynaud J, Jennings D, Holthausen T, Di Polo A, Fortune B. Utility of Light-Adapted Full-Field Electroretinogram ON and OFF Responses for Detecting Glaucomatous Functional Damage. Transl Vis Sci Technol 2023; 12:16. [PMID: 37594448 PMCID: PMC10445177 DOI: 10.1167/tvst.12.8.16] [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: 12/19/2022] [Accepted: 07/13/2023] [Indexed: 08/19/2023] Open
Abstract
Purpose To compare parameters of electroretinogram (ERG) responses for their ability to detect functional loss in early stages of nonhuman primate (NHP) experimental glaucoma (EG), including photopic negative responses (PhNR) to a standard brief red flash on a blue background (R/B) and 200-ms-long R/B and white-on-white (W/W) flashes, to W/W flicker stimuli (5-50 Hz), and to a dark-adapted intensity series. Methods Light-adapted ERGs were recorded in 12 anesthetized monkeys with unilateral EG. Amplitudes and implicit times of the a-wave, b-wave, and d-wave were measured, as well as amplitudes of PhNRs and oscillatory potentials for flash onset and offset. Flicker ERGs were measured using peak-trough and fundamental frequency analyses. Dark-adapted ERG parameters were modeled by Naka-Rushton relationships. Results Only PhNR amplitudes were significantly reduced in EG eyes compared to fellow control (FC) eyes. The d-wave implicit time was delayed in EG versus FC eyes only for the W/W long flash, but in all eyes it was 10 to 20 ms slower for R/B versus the W/W condition. Flicker ERGs were <0.5 ms delayed in EG versus FC overall, but amplitudes were affected only at 5 Hz. The brief R/B PhNR amplitude had the highest sensitivity to detect EG and strongest correlation to parameters of structural damage. Conclusions The PhNR to the standard brief R/B stimulus was best for detecting and following early-stage functional loss in NHP EG. Translational Relevance These results suggest that there would be no benefit in using longer duration flashes to separate onset and offset responses for clinical management of glaucoma.
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Affiliation(s)
- Michaela Dunn
- Discoveries in Sight Research Laboratories, Devers Eye Institute, Legacy Health, Portland, OR, USA
| | - Grant Cull
- Discoveries in Sight Research Laboratories, Devers Eye Institute, Legacy Health, Portland, OR, USA
| | - Juan Reynaud
- Discoveries in Sight Research Laboratories, Devers Eye Institute, Legacy Health, Portland, OR, USA
| | - Dawn Jennings
- Discoveries in Sight Research Laboratories, Devers Eye Institute, Legacy Health, Portland, OR, USA
| | - Trinity Holthausen
- Discoveries in Sight Research Laboratories, Devers Eye Institute, Legacy Health, Portland, OR, USA
| | - Adriana Di Polo
- Department of Neuroscience, Université de Montréal, Montréal, QC, Canada
- Neuroscience Division, Centre de Recherche du Centre Hospitalier, Université de Montréal, Montréal, QC, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute, Legacy Health, Portland, OR, USA
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Tribble JR, Hui F, Quintero H, El Hajji S, Bell K, Di Polo A, Williams PA. Neuroprotection in glaucoma: Mechanisms beyond intraocular pressure lowering. Mol Aspects Med 2023; 92:101193. [PMID: 37331129 DOI: 10.1016/j.mam.2023.101193] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/25/2023] [Accepted: 06/04/2023] [Indexed: 06/20/2023]
Abstract
Glaucoma is a common, complex, multifactorial neurodegenerative disease characterized by progressive dysfunction and then loss of retinal ganglion cells, the output neurons of the retina. Glaucoma is the most common cause of irreversible blindness and affects ∼80 million people worldwide with many more undiagnosed. The major risk factors for glaucoma are genetics, age, and elevated intraocular pressure. Current strategies only target intraocular pressure management and do not directly target the neurodegenerative processes occurring at the level of the retinal ganglion cell. Despite strategies to manage intraocular pressure, as many as 40% of glaucoma patients progress to blindness in at least one eye during their lifetime. As such, neuroprotective strategies that target the retinal ganglion cell and these neurodegenerative processes directly are of great therapeutic need. This review will cover the recent advances from basic biology to on-going clinical trials for neuroprotection in glaucoma covering degenerative mechanisms, metabolism, insulin signaling, mTOR, axon transport, apoptosis, autophagy, and neuroinflammation. With an increased understanding of both the basic and clinical mechanisms of the disease, we are closer than ever to a neuroprotective strategy for glaucoma.
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Affiliation(s)
- James R Tribble
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Flora Hui
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Department of Optometry & Vision Sciences, The University of Melbourne, Melbourne, Australia
| | - Heberto Quintero
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Sana El Hajji
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Katharina Bell
- NHMRC Clinical Trials Centre, University of Sydney, Australia; Eye ACP Duke-NUS, Singapore
| | - Adriana Di Polo
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
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Shiga Y, Nishida T, Jeoung JW, Di Polo A, Fortune B. Optical Coherence Tomography and Optical Coherence Tomography Angiography: Essential Tools for Detecting Glaucoma and Disease Progression. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1217125. [PMID: 37982032 PMCID: PMC10655832 DOI: 10.3389/fopht.2023.1217125] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
Early diagnosis and detection of disease progression are critical to successful therapeutic intervention in glaucoma, the leading cause of irreversible blindness worldwide. Optical coherence tomography (OCT) is a non-invasive imaging technique that allows objective quantification in vivo of key glaucomatous structural changes in the retina and the optic nerve head (ONH). Advances in OCT technology have increased the scan speed and enhanced image quality, contributing to early glaucoma diagnosis and monitoring, as well as the visualization of critically important structures deep within the ONH, such as the lamina cribrosa. OCT angiography (OCTA) is a dye-free technique for noninvasively assessing ocular microvasculature, including capillaries within each plexus serving the macula, peripapillary retina and ONH regions, as well as the deeper vessels of the choroid. This layer-specific assessment of the microvasculature has provided evidence that retinal and choroidal vascular impairments can occur during early stages of glaucoma, suggesting that OCTA-derived measurements could be used as biomarkers for enhancing detection of glaucoma and its progression, as well as to reveal novel insights about pathophysiology. Moreover, these innovations have demonstrated that damage to the macula, a critical region for the vision-related quality of life, can be observed in the early stages of glaucomatous eyes, leading to a paradigm shift in glaucoma monitoring. Other advances in software and hardware, such as artificial intelligence-based algorithms, adaptive optics, and visible-light OCT, may further benefit clinical management of glaucoma in the future. This article reviews the utility of OCT and OCTA for glaucoma diagnosis and disease progression detection, emphasizes the importance of detecting macula damage in glaucoma, and highlights the future perspective of OCT and OCTA. We conclude that the OCT and OCTA are essential glaucoma detection and monitoring tools, leading to clinical and economic benefits for patients and society.
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Affiliation(s)
- Yukihiro Shiga
- Neuroscience Division, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 0A9, Canada
- Department of Neuroscience, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Takashi Nishida
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California, San Diego, La Jolla, California 92093, USA
| | - Jin Wook Jeoung
- Department of Ophthalmology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Adriana Di Polo
- Neuroscience Division, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Québec H2X 0A9, Canada
- Department of Neuroscience, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, 1225 NE Second Avenue, Portland, Oregon 97232, USA
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11
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Sharif NA. Recently Approved Drugs for Lowering and Controlling Intraocular Pressure to Reduce Vision Loss in Ocular Hypertensive and Glaucoma Patients. Pharmaceuticals (Basel) 2023; 16:791. [PMID: 37375739 DOI: 10.3390/ph16060791] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 05/17/2023] [Accepted: 05/19/2023] [Indexed: 06/29/2023] Open
Abstract
Serious vision loss occurs in patients affected by chronically raised intraocular pressure (IOP), a characteristic of many forms of glaucoma where damage to the optic nerve components causes progressive degeneration of retinal and brain neurons involved in visual perception. While many risk factors abound and have been validated for this glaucomatous optic neuropathy (GON), the major one is ocular hypertension (OHT), which results from the accumulation of excess aqueous humor (AQH) fluid in the anterior chamber of the eye. Millions around the world suffer from this asymptomatic and progressive degenerative eye disease. Since clinical evidence has revealed a strong correlation between the reduction in elevated IOP/OHT and GON progression, many drugs, devices, and surgical techniques have been developed to lower and control IOP. The constant quest for new pharmaceuticals and other modalities with superior therapeutic indices has recently yielded health authority-approved novel drugs with unique pharmacological signatures and mechanism(s) of action and AQH drainage microdevices for effectively and durably treating OHT. A unique nitric oxide-donating conjugate of latanoprost, an FP-receptor prostaglandin (PG; latanoprostene bunod), new rho kinase inhibitors (ripasudil; netarsudil), a novel non-PG EP2-receptor-selective agonist (omidenepag isopropyl), and a form of FP-receptor PG in a slow-release intracameral implant (Durysta) represent the additions to the pharmaceutical toolchest to mitigate the ravages of OHT. Despite these advances, early diagnosis of OHT and glaucoma still lags behind and would benefit from further concerted effort and attention.
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Affiliation(s)
- Najam A Sharif
- Eye-APC Duke-NUS Medical School, Singapore 169856, Singapore
- Singapore Eye Research Institute, Singapore 169856, Singapore
- Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center, Fort Worth, TX 76107, USA
- Department of Pharmacy Sciences, Creighton University, Omaha, NE 68178, USA
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Texas Southern University, Houston, TX 77004, USA
- Imperial College of Science and Technology, St. Mary's Campus, London SW7 2BX, UK
- Institute of Ophthalmology, University College London, London WC1E 6BT, UK
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12
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Sharif NA, Odani-Kawabata N, Lu F, Pinchuk L. FP and EP2 prostanoid receptor agonist drugs and aqueous humor outflow devices for treating ocular hypertension and glaucoma. Exp Eye Res 2023; 229:109415. [PMID: 36803996 DOI: 10.1016/j.exer.2023.109415] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/21/2022] [Accepted: 02/08/2023] [Indexed: 02/21/2023]
Abstract
Prostaglandin (PG) receptors represent important druggable targets due to the many diverse actions of PGs in the body. From an ocular perspective, the discovery, development, and health agency approvals of prostaglandin F (FP) receptor agonists (FPAs) have revolutionized the medical treatment of ocular hypertension (OHT) and glaucoma. FPAs, such as latanoprost, travoprost, bimatoprost, and tafluprost, powerfully lower and control intraocular pressure (IOP), and became first-line therapeutics to treat this leading cause of blindness in the late 1990s to early 2000s. More recently, a latanoprost-nitric oxide (NO) donor conjugate, latanoprostene bunod, and a novel FP/EP3 receptor dual agonist, sepetaprost (ONO-9054 or DE-126), have also demonstrated robust IOP-reducing activity. Moreover, a selective non-PG prostanoid EP2 receptor agonist, omidenepag isopropyl (OMDI), was discovered, characterized, and has been approved in the United States, Japan and several other Asian countries for treating OHT/glaucoma. FPAs primarily enhance uveoscleral (UVSC) outflow of aqueous humor (AQH) to reduce IOP, but cause darkening of the iris and periorbital skin, uneven thickening and elongation of eyelashes, and deepening of the upper eyelid sulcus during chronic treatment. In contrast, OMDI lowers and controls IOP by activation of both the UVSC and trabecular meshwork outflow pathways, and it has a lower propensity to induce the aforementioned FPA-induced ocular side effects. Another means to address OHT is to physically promote the drainage of the AQH from the anterior chamber of the eye of patients with OHT/glaucoma. This has successfully been achieved by the recent approval and introduction of miniature devices into the anterior chamber by minimally invasive glaucoma surgeries. This review covers the three major aspects mentioned above to highlight the etiology of OHT/glaucoma, and the pharmacotherapeutics and devices that can be used to combat this blinding ocular disease.
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Affiliation(s)
- Najam A Sharif
- Ophthalmology Innovation Center, Santen Inc., Emeryville, CA, USA; Singapore Eye Research Institute, Singapore; Eye-ACP Duke-National University of Singapore Medical School, Singapore; Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center, Fort Worth, TX, USA; Department of Pharmacy Sciences, Creighton University, Omaha, NE, USA; Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Texas Southern University, Houston, TX, USA; Imperial College of Science and Technology, St. Mary's Campus, London, UK; Institute of Ophthalmology, University College London, London, UK.
| | | | - Fenghe Lu
- Product Development Division, Santen Inc., Emeryville, CA, USA
| | - Leonard Pinchuk
- Ophthalmology Innovation Center, Santen Inc., Emeryville, CA, USA; Biomedical Engineering Department, University of Miami, Miami, FL, USA
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Pacwa A, Machowicz J, Akhtar S, Rodak P, Liu X, Pietrucha-Dutczak M, Lewin-Kowalik J, Amadio M, Smedowski A. Deficiency of the RNA-binding protein ELAVL1/HuR leads to the failure of endogenous and exogenous neuroprotection of retinal ganglion cells. Front Cell Neurosci 2023; 17:1131356. [PMID: 36874215 PMCID: PMC9982123 DOI: 10.3389/fncel.2023.1131356] [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: 12/24/2022] [Accepted: 02/06/2023] [Indexed: 02/19/2023] Open
Abstract
Introduction ELAVL1/HuR is a keystone regulator of gene expression at the posttranscriptional level, including stress response and homeostasis maintenance. The aim of this study was to evaluate the impact of hur silencing on the age-related degeneration of retinal ganglion cells (RGC), which potentially describes the efficiency of endogenous neuroprotection mechanisms, as well as to assess the exogenous neuroprotection capacity of hur-silenced RGC in the rat glaucoma model. Methods The study consisted of in vitro and in vivo approaches. In vitro, we used rat B-35 cells to investigate, whether AAV-shRNA-HuR delivery affects survival and oxidative stress markers under temperature and excitotoxic insults. In vivo approach consisted of two different settings. In first one, 35 eight-week-old rats received intravitreal injection of AAV-shRNA-HuR or AAV-shRNA scramble control. Animals underwent electroretinography tests and were sacrificed 2, 4 or 6 months after injection. Retinas and optic nerves were collected and processed for immunostainings, electron microscopy and stereology. For the second approach, animals received similar gene constructs. To induce chronic glaucoma, 8 weeks after AAV injection, unilateral episcleral vein cauterization was performed. Animals from each group received intravitreal injection of metallothionein II. Animals underwent electroretinography tests and were sacrificed 8 weeks later. Retinas and optic nerves were collected and processed for immunostainings, electron microscopy and stereology. Results Silencing of hur induced apoptosis and increased oxidative stress markers in B-35 cells. Additionally, shRNA treatment impaired the cellular stress response to temperature and excitotoxic insults. In vivo, RGC count was decreased by 39% in shRNA-HuR group 6 months after injection, when compared to shRNA scramble control group. In neuroprotection study, the average loss of RGCs was 35% in animals with glaucoma treated with metallothionein and shRNA-HuR and 11.4% in animals with glaucoma treated with metallothionein and the scramble control shRNA. An alteration in HuR cellular content resulted in diminished photopic negative responses in the electroretinogram. Conclusions Based on our findings, we conclude that HuR is essential for the survival and efficient neuroprotection of RGC and that the induced alteration in HuR content accelerates both the age-related and glaucoma-induced decline in RGC number and function, further confirming HuR's key role in maintaining cell homeostasis and its possible involvement in the pathogenesis of glaucoma.
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Affiliation(s)
- Anna Pacwa
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia in Katowice, Katowice, Poland.,GlaucoTech Co., Katowice, Poland
| | - Joanna Machowicz
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia in Katowice, Katowice, Poland
| | - Saeed Akhtar
- College of Applied Medical Sciences, Inaya Medical Colleges, Riyadh, Saudi Arabia.,Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Piotr Rodak
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia in Katowice, Katowice, Poland
| | - Xiaonan Liu
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia in Katowice, Katowice, Poland.,Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Marita Pietrucha-Dutczak
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia in Katowice, Katowice, Poland
| | - Joanna Lewin-Kowalik
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia in Katowice, Katowice, Poland.,GlaucoTech Co., Katowice, Poland
| | - Marialaura Amadio
- Department of Drug Sciences, Section of Pharmacology, The University of Pavia, Pavia, Italy
| | - Adrian Smedowski
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia in Katowice, Katowice, Poland.,GlaucoTech Co., Katowice, Poland
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14
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Pitale PM, Shen G, Sigireddi RR, Polo-Prieto M, Park YH, Gibson SE, Westenskow PD, Channa R, Frankfort BJ. Selective vulnerability of the intermediate retinal capillary plexus precedes retinal ganglion cell loss in ocular hypertension. Front Cell Neurosci 2022; 16:1073786. [PMID: 36545655 PMCID: PMC9760765 DOI: 10.3389/fncel.2022.1073786] [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: 10/18/2022] [Accepted: 11/15/2022] [Indexed: 12/08/2022] Open
Abstract
Introduction: Glaucoma, a disease of retinal ganglion cell (RGC) injury and potentially devastating vision loss, is associated with both ocular hypertension (OHT) and reduced ocular blood flow. However, the relationship between OHT and retinal capillary architecture is not well understood. In this project, we studied microvasculature damage in mice exposed to mild levels of induced OHT. Methods: Mild OHT was induced with the microbead model for 2 weeks. At this time point, some retinas were immunostained with CD31 (endothelium), Collagen IV (basement membrane), and RBPMS (RGCs) for z-stack confocal microscopy. We processed these confocal images to distinguish the three retinal capillary plexi (superficial, intermediate, and deep). We manually counted RGC density, analyzed vascular complexity, and identified topographical and spatial vascular features of the retinal capillaries using a combination of novel manual and automated workflows. Other retinas were dissociated and immunopanned to isolate RGCs and amacrine cells (ACs) for hypoxia gene array analysis. Results: RGC counts were normal but there was decreased overall retinal capillary complexity. This reduced complexity could be explained by abnormalities in the intermediate retinal capillary plexus (IRCP) that spared the other plexi. Capillary junction density, vessel length, and vascular area were all significantly reduced, and the number of acellular capillaries was dramatically increased. ACs, which share a neurovascular unit (NVU) with the IRCP, displayed a marked increase in the relative expression of many hypoxia-related genes compared to RGCs from the same preparations. Discussion: We have discovered a rapidly occurring, IRCP-specific, OHT-induced vascular phenotype that precedes RGC loss. AC/IRCP NVU dysfunction may be a mechanistic link for early vascular remodeling in glaucoma.
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Affiliation(s)
- Priyamvada M. Pitale
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Guofu Shen
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Rohini R. Sigireddi
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Maria Polo-Prieto
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Yong H. Park
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Solomon E. Gibson
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States,Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
| | - Peter D. Westenskow
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States
| | - Roomasa Channa
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, United States
| | - Benjamin J. Frankfort
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, United States,Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States,*Correspondence: Benjamin J. Frankfort
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15
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Norcia AM, Yakovleva A, Jehangir N, Goldberg JL. Preferential Loss of Contrast Decrement Responses in Human Glaucoma. Invest Ophthalmol Vis Sci 2022; 63:16. [PMID: 36264656 PMCID: PMC9587510 DOI: 10.1167/iovs.63.11.16] [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] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to determine whether glaucoma in human patients produces preferential damage to OFF visual pathways, as suggested by animal experimental models, patient electroretinogram (ERG), and retinal imaging data. Methods Steady-state visual evoked potentials (SSVEPs) were recorded monocularly from 50 patients with glaucoma and 28 age-similar controls in response to equal Weber contrast increments and decrements presented using 2.73 hertz (Hz) sawtooth temporal waveforms. Results The eyes of patients with glaucoma were separated into mild (better than -6 decibel [dB] mean deviation; n = 28) and moderate to severe (worse than -6 dB mean deviation, n = 22) groups based on their Humphrey 24-2 visual field measurements. Response amplitudes and phases from the two glaucoma-severity groups were compared to controls at the group level. SSVEP amplitudes were depressed in both glaucoma groups, more so in the moderate to severe glaucoma group. The differences between controls and the moderate-severe glaucoma groups were more statistically reliable for decrements than for increments. Mean responses to decremental sawtooth stimuli were larger than those to increments in controls and in the mild glaucoma but not in the moderate to severe glaucoma group at the first harmonic. OFF/decrement responses at the first harmonic were faster in controls, but not in patients. Conclusions The observed pattern of preferential loss of decremental responses in human glaucoma is consistent with prior reports of selective damage to OFF retinal ganglion cells in murine models and in data from human ERG and retinal imaging. These data motivate pursuit of SSVEP as a biomarker for glaucoma progression.
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Affiliation(s)
- Anthony M. Norcia
- Department of Psychology, Wu Tsai Neurosciences Institute, Stanford University, Stanford, California, United States
| | - Alexandra Yakovleva
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Naz Jehangir
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Jeffrey L. Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Department of Ophthalmology, Stanford University, Stanford, California, United States
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16
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Van Hook MJ. Influences of Glaucoma on the Structure and Function of Synapses in the Visual System. Antioxid Redox Signal 2022; 37:842-861. [PMID: 35044228 PMCID: PMC9587776 DOI: 10.1089/ars.2021.0253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 12/31/2021] [Indexed: 11/12/2022]
Abstract
Significance: Glaucoma is an age-related neurodegenerative disorder of the visual system associated with sensitivity to intraocular pressure (IOP). It is the leading irreversible cause of vision loss worldwide, and vision loss results from damage and dysfunction of the retinal output neurons known as retinal ganglion cells (RGCs). Recent Advances: Elevated IOP and optic nerve injury triggers pruning of RGC dendrites, altered morphology of excitatory inputs from presynaptic bipolar cells, and disrupted RGC synaptic function. Less is known about RGC outputs, although evidence to date indicates that glaucoma is associated with altered mitochondrial and synaptic structure and function in RGC-projection targets in the brain. These early functional changes likely contribute to vision loss and might be a window into early diagnosis and treatment. Critical Issues: Glaucoma affects different RGC populations to varying extents and along distinct time courses. The influence of glaucoma on RGC synaptic function as well as the mechanisms underlying these effects remain to be determined. Since RGCs are an especially energetically demanding population of neurons, altered intracellular axon transport of mitochondria and mitochondrial function might contribute to RGC synaptic dysfunction in the retina and brain as well as RGC vulnerability in glaucoma. Future Directions: The mechanisms underlying differential RGC vulnerability remain to be determined. Moreover, the timing and mechanisms of RGCs synaptic dysfunction and degeneration will provide valuable insight into the disease process in glaucoma. Future work will be able to capitalize on these findings to better design diagnostic and therapeutic approaches to detect disease and prevent vision loss. Antioxid. Redox Signal. 37, 842-861.
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Affiliation(s)
- Matthew J. Van Hook
- Department of Ophthalmology & Visual Science and Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Cellular & Integrative Physiology, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA
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17
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Kowal TJ, Dhande OS, Wang B, Wang Q, Ning K, Liu W, Berbari NF, Hu Y, Sun Y. Distribution of prototypical primary cilia markers in subtypes of retinal ganglion cells. J Comp Neurol 2022; 530:2176-2187. [PMID: 35434813 PMCID: PMC9219574 DOI: 10.1002/cne.25326] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/27/2022] [Accepted: 03/21/2022] [Indexed: 11/07/2022]
Abstract
Loss of retinal ganglion cells (RGCs) underlies several forms of retinal disease including glaucomatous optic neuropathy, a leading cause of irreversible blindness. Several rare genetic disorders associated with cilia dysfunction have retinal degeneration as a clinical hallmark. Much of the focus of ciliopathy associated blindness is on the connecting cilium of photoreceptors; however, RGCs also possess primary cilia. It is unclear what roles RGC cilia play, what proteins and signaling machinery localize to RGC cilia, or how RGC cilia are differentiated across the subtypes of RGCs. To better understand these questions, we assessed the presence or absence of a prototypical cilia marker Arl13b and a widely distributed neuronal cilia marker AC3 in different subtypes of mouse RGCs. Interestingly, not all RGC subtype cilia are the same and there are significant differences even among these standard cilia markers. Alpha-RGCs positive for osteopontin, calretinin, and SMI32 primarily possess AC3-positive cilia. Directionally selective RGCs that are CART positive or Trhr positive localize either Arl13b or AC3, respectively, in cilia. Intrinsically photosensitive RGCs differentially localize Arl13b and AC3 based on melanopsin expression. Taken together, we characterized the localization of gold standard cilia markers in different subtypes of RGCs and conclude that cilia within RGC subtypes may be differentially organized. Future studies aimed at understanding RGC cilia function will require a fundamental ability to observe the cilia across subtypes as their signaling protein composition is elucidated. A comprehensive understanding of RGC cilia may reveal opportunities to understanding how their dysfunction leads to retinal degeneration.
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Affiliation(s)
- Tia J. Kowal
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Onkar S. Dhande
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Biao Wang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Qing Wang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Ke Ning
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Wendy Liu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Nicolas F. Berbari
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis IN 46202 USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, 94304, USA
- Palo Alto Veterans Administration, Palo Alto, CA 94304
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18
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Sharif NA. Degeneration of retina-brain components and connections in glaucoma: Disease causation and treatment options for eyesight preservation. CURRENT RESEARCH IN NEUROBIOLOGY 2022; 3:100037. [PMID: 36685768 PMCID: PMC9846481 DOI: 10.1016/j.crneur.2022.100037] [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: 03/15/2022] [Revised: 03/30/2022] [Accepted: 04/01/2022] [Indexed: 01/25/2023] Open
Abstract
Eyesight is the most important of our sensory systems for optimal daily activities and overall survival. Patients who experience visual impairment due to elevated intraocular pressure (IOP) are often those afflicted with primary open-angle glaucoma (POAG) which slowly robs them of their vision unless treatment is administered soon after diagnosis. The hallmark features of POAG and other forms of glaucoma are damaged optic nerve, retinal ganglion cell (RGC) loss and atrophied RGC axons connecting to various brain regions associated with receipt of visual input from the eyes and eventual decoding and perception of images in the visual cortex. Even though increased IOP is the major risk factor for POAG, the disease is caused by many injurious chemicals and events that progress slowly within all components of the eye-brain visual axis. Lowering of IOP mitigates the damage to some extent with existing drugs, surgical and device implantation therapeutic interventions. However, since multifactorial degenerative processes occur during aging and with glaucomatous optic neuropathy, different forms of neuroprotective, nutraceutical and electroceutical regenerative and revitalizing agents and processes are being considered to combat these eye-brain disorders. These aspects form the basis of this short review article.
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Affiliation(s)
- Najam A. Sharif
- Duke-National University of Singapore Medical School, Singapore,Singapore Eye Research Institute (SERI), Singapore,Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center, Fort Worth, Texas, USA,Department of Pharmaceutical Sciences, Texas Southern University, Houston, TX, USA,Department of Surgery & Cancer, Imperial College of Science and Technology, St. Mary's Campus, London, UK,Department of Pharmacy Sciences, School of School of Pharmacy and Health Professions, Creighton University, Omaha, NE, USA,Ophthalmology Innovation Center, Santen Incorporated, 6401 Hollis Street (Suite #125), Emeryville, CA, 94608, USA,Ophthalmology Innovation Center, Santen Incorporated, 6401 Hollis Street (Suite #125), Emeryville, CA, 94608, USA.
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19
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Lee PY, Zhao D, Wong VHY, Chrysostomou V, Crowston JG, Bui BV. The Effect of Aging on Retinal Function and Retinal Ganglion Cell Morphology Following Intraocular Pressure Elevation. Front Aging Neurosci 2022; 14:859265. [PMID: 35645783 PMCID: PMC9133539 DOI: 10.3389/fnagi.2022.859265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
Aging and elevated intraocular pressure (IOP) are two major risk factors for glaucomatous optic neuropathy; a condition characterized by the selective, progressive injury, and subsequent loss of retinal ganglion cells (RGCs). We examined how age modified the capacity for RGCs to functionally recover following a reproducible IOP elevation (50 mmHg for 30 min). We found that RGC functional recovery (measured using electroretinography) was complete by 7 days in 3-month-old mice but was delayed in 12-month-old mice until 14 days. At the 7-day recovery endpoint when RGC function had recovered in young but not older eyes, we examined RGC structural responses to IOP-related stress by analyzing RGC dendritic morphology. ON-RGC cell volume was attenuated following IOP elevation in both young and older mice. We also found that following IOP elevation OFF-RGC dendritic morphology became less complex per cell volume in young mice, an effect that was not observed in older eyes. Our data suggest that adaptations in OFF-RGCs in young eyes were associated with better functional recovery 7 days after IOP elevation. Loss of RGC cellular adaptations may account for delayed functional recovery in older eyes.
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Affiliation(s)
- Pei Ying Lee
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Da Zhao
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Vickie H. Y. Wong
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Vicki Chrysostomou
- Singapore Eye Research Institute, Singapore, Singapore,Duke-NUS Medical School, Singapore, Singapore
| | - Jonathan G. Crowston
- Singapore Eye Research Institute, Singapore, Singapore,Duke-NUS Medical School, Singapore, Singapore
| | - Bang V. Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia,*Correspondence: Bang V. Bui,
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20
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Lu SY, Zhang XJ, Wang YM, Yuan N, Kam KW, Chan PP, Tam PO, Yip WW, Young AL, Tham CC, Pang CP, Yam JC, Chen LJ. Association of SIX1-SIX6 polymorphisms with peripapillary retinal nerve fibre layer thickness in children. Br J Ophthalmol 2022:bjophthalmol-2021-319756. [PMID: 35017159 DOI: 10.1136/bjophthalmol-2021-319756] [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: 05/27/2021] [Accepted: 12/10/2021] [Indexed: 11/04/2022]
Abstract
PURPOSE Association of SIX1-SIX6 variants with peripapillary retinal nerve fibre layer (p-RNFL) thickness had been reported in adults. This study aimed to investigate these associations in children, with further explorations by spatial, age and sex stratifications. METHODS 2878 school children aged between 6 and 9 years were enrolled from the Hong Kong Children Eye Study. Three single-nucleotide polymorphisms (SNPs) at the SIX1-SIX6 locus were genotyped. The association of each SNP with p-RNFL thickness (including global and sectoral thickness) were evaluated using multiple linear regression. RESULTS SNPs rs33912345 (p=7.7×10-4) and rs10483727 (p=0.0013) showed significant associations with temporal-inferior p-RNFL thickness. The C allele of rs33912345 was associated with a thinner temporal-inferior p-RNFL by an average of 2.44 µm, while rs10483727-T was associated with a thinner temporal-inferior p-RNFL by 2.32 µm. The association with temporal-inferior p-RNFL was the strongest in the 8-9 year-old group for rs33912345 (p=5.2×10-4) and rs10483727 (p=3.3×10-4). Both SNPs were significantly associated with temporal-inferior p-RNFL thickness in boys (p<0.0017), but not in girls (p>0.05). In contrast, rs12436579-C (β=1.66; p=0.0059), but not rs33912345-C (β=1.31; p=0.052) or rs10483727-T (β=1.19; p=0.078), was nominally associated with a thicker nasal-inferior p-RNFL. CONCLUSIONS Both rs33912345 and rs10483727 at SIX1-SIX6 were associated with p-RNFL thickness in children, especially at the temporal-inferior sector, with age-dependent and sex-specific effects. SNP rs12436579 was associated with nasal-inferior p-RNFL thickness. Our findings suggested a role of SIX1-SIX6 in RNFL variation during neural retina development in childhood.
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Affiliation(s)
- Shi Yao Lu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Xiu Juan Zhang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Yu Meng Wang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Nan Yuan
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Ka Wai Kam
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
| | - Poemen P Chan
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Hong Kong Eye Hospital, Hong Kong, China
| | - Pancy Os Tam
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Wilson Wk Yip
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
| | - Alvin L Young
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
| | - Clement C Tham
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Hong Kong Eye Hospital, Hong Kong, China.,Hong Kong Hub of Paediatric Excellence, The Chinese University of Hong Kong, Hong Kong, China
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Hong Kong Hub of Paediatric Excellence, The Chinese University of Hong Kong, Hong Kong, China
| | - Jason C Yam
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China .,Hong Kong Eye Hospital, Hong Kong, China.,Hong Kong Hub of Paediatric Excellence, The Chinese University of Hong Kong, Hong Kong, China
| | - Li Jia Chen
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China .,Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China.,Hong Kong Hub of Paediatric Excellence, The Chinese University of Hong Kong, Hong Kong, China
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21
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Ghassabi Z, Kuranov RV, Schuman JS, Zambrano R, Wu M, Liu M, Tayebi B, Wang Y, Rubinoff I, Liu X, Wollstein G, Zhang HF, Ishikawa H. In Vivo Sublayer Analysis of Human Retinal Inner Plexiform Layer Obtained by Visible-Light Optical Coherence Tomography. Invest Ophthalmol Vis Sci 2022; 63:18. [PMID: 35024761 PMCID: PMC8762683 DOI: 10.1167/iovs.63.1.18] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Purpose Growing evidence suggests that dendrite retraction or degeneration in a subpopulation of the retinal ganglion cells (RGCs) may precede detectable soma abnormalities and RGC death in glaucoma. Visualization of the lamellar structure of the inner plexiform layer (IPL) could advance clinical management and fundamental understanding of glaucoma. We investigated whether visible-light optical coherence tomography (vis-OCT) could detect the difference in the IPL sublayer thicknesses between small cohorts of healthy and glaucomatous subjects. Method We imaged nine healthy and five glaucomatous subjects with vis-OCT. Four of the healthy subjects were scanned three times each in two separate visits, and five healthy and five glaucoma subjects were scanned three times during a single visit. IPL sublayers were manually segmented using averaged A-line profiles. Results The mean ages of glaucoma and healthy subjects are 59.6 ± 13.4 and 45.4 ± 14.4 years (P = 0.02.) The visual field mean deviations (MDs) are −26.4 to −7.7 dB in glaucoma patients and −1.6 to 1.1 dB in healthy subjects (P = 0.002). Median coefficients of variation (CVs) of intrasession repeatability for the entire IPL and three sublayers are 3.1%, 5.6%, 6.9%, and 5.6% in healthy subjects and 1.8%, 6.0%, 7.7%, and 6.2% in glaucoma patients, respectively. The mean IPL thicknesses are 36.2 ± 1.5 µm in glaucomatous and 40.1 ± 1.7 µm in healthy eyes (P = 0.003). Conclusions IPL sublayer analysis revealed that the middle sublayer could be responsible for the majority of IPL thinning in glaucoma. Vis-OCT quantified IPL sublayers with good repeatability in both glaucoma and healthy subjects.
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Affiliation(s)
- Zeinab Ghassabi
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Roman V Kuranov
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States.,Opticent Inc., Evanston, Illinois, United States
| | - Joel S Schuman
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States.,Neuroscience Institute, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Department of Electrical and Computer Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States.,Center for Neural Science, NYU College of Arts and Sciences, New York, New York, United States.,Department of Physiology and Neuroscience, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Ronald Zambrano
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Mengfei Wu
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Mengling Liu
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Behnam Tayebi
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Neuroscience Institute, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Yuanbo Wang
- Opticent Inc., Evanston, Illinois, United States
| | - Ian Rubinoff
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Xiaorong Liu
- Department of Biology, University of Virginia, Charlottesville, Virginia, United States
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Hiroshi Ishikawa
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States.,Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
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22
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Deng W, Hedberg-Buenz A, Soukup DA, Taghizadeh S, Wang K, Anderson MG, Garvin MK. AxonDeep: Automated Optic Nerve Axon Segmentation in Mice With Deep Learning. Transl Vis Sci Technol 2021; 10:22. [PMID: 34932117 PMCID: PMC8709929 DOI: 10.1167/tvst.10.14.22] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Optic nerve damage is the principal feature of glaucoma and contributes to vision loss in many diseases. In animal models, nerve health has traditionally been assessed by human experts that grade damage qualitatively or manually quantify axons from sampling limited areas from histologic cross sections of nerve. Both approaches are prone to variability and are time consuming. First-generation automated approaches have begun to emerge, but all have significant shortcomings. Here, we seek improvements through use of deep-learning approaches for segmenting and quantifying axons from cross-sections of mouse optic nerve. Methods Two deep-learning approaches were developed and evaluated: (1) a traditional supervised approach using a fully convolutional network trained with only labeled data and (2) a semisupervised approach trained with both labeled and unlabeled data using a generative-adversarial-network framework. Results From comparisons with an independent test set of images with manually marked axon centers and boundaries, both deep-learning approaches outperformed an existing baseline automated approach and similarly to two independent experts. Performance of the semisupervised approach was superior and implemented into AxonDeep. Conclusions AxonDeep performs automated quantification and segmentation of axons from healthy-appearing nerves and those with mild to moderate degrees of damage, similar to that of experts without the variability and constraints associated with manual performance. Translational Relevance Use of deep learning for axon quantification provides rapid, objective, and higher throughput analysis of optic nerve that would otherwise not be possible.
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Affiliation(s)
- Wenxiang Deng
- Department of Electrical and Computer Engineering, The University of Iowa, Iowa City, IA, USA.,Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA
| | - Adam Hedberg-Buenz
- Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA.,Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA
| | - Dana A Soukup
- Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA.,Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA
| | - Sima Taghizadeh
- Department of Electrical and Computer Engineering, The University of Iowa, Iowa City, IA, USA
| | - Kai Wang
- Department of Biostatistics, The University of Iowa, Iowa City, IA, USA
| | - Michael G Anderson
- Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA.,Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, IA, USA
| | - Mona K Garvin
- Department of Electrical and Computer Engineering, The University of Iowa, Iowa City, IA, USA.,Iowa City VA Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, IA, USA
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23
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Di Pierdomenico J, Henderson DCM, Giammaria S, Smith VL, Jamet AJ, Smith CA, Hooper ML, Chauhan BC. Age and intraocular pressure in murine experimental glaucoma. Prog Retin Eye Res 2021; 88:101021. [PMID: 34801667 DOI: 10.1016/j.preteyeres.2021.101021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/25/2021] [Accepted: 11/08/2021] [Indexed: 12/23/2022]
Abstract
Age and intraocular pressure (IOP) are the two most important risk factors for the development and progression of open-angle glaucoma. While IOP is commonly considered in models of experimental glaucoma (EG), most studies use juvenile or adult animals and seldom older animals which are representative of the human disease. This paper provides a concise review of how retinal ganglion cell (RGC) loss, the hallmark of glaucoma, can be evaluated in EG with a special emphasis on serial in vivo imaging, a parallel approach used in clinical practice. It appraises the suitability of EG models for the purpose of in vivo imaging and argues for the use of models that provide a sustained elevation of IOP, without compromise of the ocular media. In a study with parallel cohorts of adult (3-month-old, equivalent to 20 human years) and old (2-year-old, equivalent to 70 human years) mice, we compare the effects of elevated IOP on serial ganglion cell complex thickness and individual RGC dendritic morphology changes obtained in vivo. We also evaluate how age modulates the impact of elevated IOP on RGC somal and axonal density in histological analysis as well the density of melanopsin RGCs. We discuss the challenges of using old animals and emphasize the potential of single RGC imaging for understanding the pathobiology of RGC loss and evaluating new therapeutic avenues.
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Affiliation(s)
- Johnny Di Pierdomenico
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Delaney C M Henderson
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Sara Giammaria
- Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Victoria L Smith
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Aliénor J Jamet
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Corey A Smith
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Michele L Hooper
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Balwantray C Chauhan
- Retina and Optic Nerve Research Laboratory, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada; Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada.
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24
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Cell-Based Neuroprotection of Retinal Ganglion Cells in Animal Models of Optic Neuropathies. BIOLOGY 2021; 10:biology10111181. [PMID: 34827174 PMCID: PMC8615038 DOI: 10.3390/biology10111181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/10/2021] [Accepted: 11/11/2021] [Indexed: 11/16/2022]
Abstract
Retinal ganglion cells (RGCs) comprise a heterogenous group of projection neurons that transmit visual information from the retina to the brain. Progressive degeneration of these cells, as it occurs in inflammatory, ischemic, traumatic or glaucomatous optic neuropathies, results in visual deterioration and is among the leading causes of irreversible blindness. Treatment options for these diseases are limited. Neuroprotective approaches aim to slow down and eventually halt the loss of ganglion cells in these disorders. In this review, we have summarized preclinical studies that have evaluated the efficacy of cell-based neuroprotective treatment strategies to rescue retinal ganglion cells from cell death. Intraocular transplantations of diverse genetically nonmodified cell types or cells engineered to overexpress neurotrophic factors have been demonstrated to result in significant attenuation of ganglion cell loss in animal models of different optic neuropathies. Cell-based combinatorial neuroprotective approaches represent a potential strategy to further increase the survival rates of retinal ganglion cells. However, data about the long-term impact of the different cell-based treatment strategies on retinal ganglion cell survival and detailed analyses of potential adverse effects of a sustained intraocular delivery of neurotrophic factors on retina structure and function are limited, making it difficult to assess their therapeutic potential.
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25
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Sharif NA. Therapeutic Drugs and Devices for Tackling Ocular Hypertension and Glaucoma, and Need for Neuroprotection and Cytoprotective Therapies. Front Pharmacol 2021; 12:729249. [PMID: 34603044 PMCID: PMC8484316 DOI: 10.3389/fphar.2021.729249] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/18/2021] [Indexed: 12/11/2022] Open
Abstract
Damage to the optic nerve and the death of associated retinal ganglion cells (RGCs) by elevated intraocular pressure (IOP), also known as glaucoma, is responsible for visual impairment and blindness in millions of people worldwide. The ocular hypertension (OHT) and the deleterious mechanical forces it exerts at the back of the eye, at the level of the optic nerve head/optic disc and lamina cribosa, is the only modifiable risk factor associated with glaucoma that can be treated. The elevated IOP occurs due to the inability of accumulated aqueous humor (AQH) to egress from the anterior chamber of the eye due to occlusion of the major outflow pathway, the trabecular meshwork (TM) and Schlemm’s canal (SC). Several different classes of pharmaceutical agents, surgical techniques and implantable devices have been developed to lower and control IOP. First-line drugs to promote AQH outflow via the uveoscleral outflow pathway include FP-receptor prostaglandin (PG) agonists (e.g., latanoprost, travoprost and tafluprost) and a novel non-PG EP2-receptor agonist (omidenepag isopropyl, Eybelis®). TM/SC outflow enhancing drugs are also effective ocular hypotensive agents (e.g., rho kinase inhibitors like ripasudil and netarsudil; and latanoprostene bunod, a conjugate of a nitric oxide donor and latanoprost). One of the most effective anterior chamber AQH microshunt devices is the Preserflo® microshunt which can lower IOP down to 10–13 mmHg. Other IOP-lowering drugs and devices on the horizon will be also discussed. Additionally, since elevated IOP is only one of many risk factors for development of glaucomatous optic neuropathy, a treatise of the role of inflammatory neurodegeneration of the optic nerve and retinal ganglion cells and appropriate neuroprotective strategies to mitigate this disease will also be reviewed and discussed.
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Affiliation(s)
- Najam A Sharif
- Global Alliances and External Research, Ophthalmology Innovation Center, Santen Inc., Emeryville, CA, United States
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26
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Della Santina L, Yu AK, Harris SC, Soliño M, Garcia Ruiz T, Most J, Kuo YM, Dunn FA, Ou Y. Disassembly and rewiring of a mature converging excitatory circuit following injury. Cell Rep 2021; 36:109463. [PMID: 34348156 PMCID: PMC8381591 DOI: 10.1016/j.celrep.2021.109463] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 05/24/2021] [Accepted: 07/08/2021] [Indexed: 01/22/2023] Open
Abstract
Specificity and timing of synapse disassembly in the CNS are essential to learning how individual circuits react to neurodegeneration of the postsynaptic neuron. In sensory systems such as the mammalian retina, synaptic connections of second-order neurons are known to remodel and reconnect in the face of sensory cell loss. Here we analyzed whether degenerating third-order neurons can remodel their local presynaptic connectivity. We injured adult retinal ganglion cells by transiently elevating intraocular pressure. We show that loss of presynaptic structures occurs before postsynaptic density proteins and accounts for impaired transmission from presynaptic neurons, despite no evidence of presynaptic cell loss, axon terminal shrinkage, or reduced functional input. Loss of synapses is biased among converging presynaptic neuron types, with preferential loss of the major excitatory cone-driven partner and increased connectivity with rod-driven presynaptic partners, demonstrating that this adult neural circuit is capable of structural plasticity while undergoing neurodegeneration. Della Santina et al. injure a converging excitatory circuit in the adult retina by intraocular pressure elevation. Postsynaptic retinal ganglion cells disconnect from presynaptic bipolar cells with stereotyped bias against their major partner and rewire with developmental presynaptic partners, underscoring the potential of the adult CNS to adopt developmental patterns.
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Affiliation(s)
- Luca Della Santina
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94158, USA; Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Alfred K Yu
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Scott C Harris
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94158, USA; Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Manuel Soliño
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Tonatiuh Garcia Ruiz
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jesse Most
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Yien-Ming Kuo
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Felice A Dunn
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Yvonne Ou
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA 94158, USA.
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27
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A Fair Assessment of Evaluation Tools for the Murine Microbead Occlusion Model of Glaucoma. Int J Mol Sci 2021; 22:ijms22115633. [PMID: 34073191 PMCID: PMC8199180 DOI: 10.3390/ijms22115633] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/14/2021] [Accepted: 05/19/2021] [Indexed: 02/06/2023] Open
Abstract
Despite being one of the most studied eye diseases, clinical translation of glaucoma research is hampered, at least in part, by the lack of validated preclinical models and readouts. The most popular experimental glaucoma model is the murine microbead occlusion model, yet the observed mild phenotype, mixed success rate, and weak reproducibility urge for an expansion of available readout tools. For this purpose, we evaluated various measures that reflect early onset glaucomatous changes in the murine microbead occlusion model. Anterior chamber depth measurements and scotopic threshold response recordings were identified as an outstanding set of tools to assess the model’s success rate and to chart glaucomatous damage (or neuroprotection in future studies), respectively. Both are easy-to-measure, in vivo tools with a fast acquisition time and high translatability to the clinic and can be used, whenever judged beneficial, in combination with the more conventional measures in present-day glaucoma research (i.e., intraocular pressure measurements and post-mortem histological analyses). Furthermore, we highlighted the use of dendritic arbor analysis as an alternative histological readout for retinal ganglion cell density counts.
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28
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Gubin D, Neroev V, Malishevskaya T, Cornelissen G, Astakhov SY, Kolomeichuk S, Yuzhakova N, Kabitskaya Y, Weinert D. Melatonin mitigates disrupted circadian rhythms, lowers intraocular pressure, and improves retinal ganglion cells function in glaucoma. J Pineal Res 2021; 70:e12730. [PMID: 33730443 DOI: 10.1111/jpi.12730] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/11/2021] [Accepted: 03/12/2021] [Indexed: 02/06/2023]
Abstract
Glaucoma is a progressive optic neuropathy associated with damage to retinal ganglion cells (RGCs) and disrupted circadian rhythms. Melatonin is a promising substance to ameliorate glaucoma-associated compromised circadian rhythms, sleep, mood, and retinal cells function. However, studies estimating melatonin effects in glaucoma are currently lacking. Therefore, In this study, we investigated the effect of long-term (daily at 10:30 pm for 90 days) oral melatonin administration on systemic (Tb) and local to the organ of vision (IOP) circadian rhythms, pattern electroretinogram (PERG), sleep, and mood, depending on glaucoma stage in patients diagnosed with stable or advanced primary open-angle glaucoma. In a laboratory study in 15 of them, 24-hour records of salivary melatonin were obtained and MTNR1B receptor gene polymorphism was assessed. Melatonin increased the stability of the Tb circadian rhythm by improving its phase alignment and alignment with IOP. Melatonin time-dependently decreased IOP and IOP standard deviation (SD). IOP 24-hour mean and IOP SD decreases were more pronounced in individuals with the higher initial 24-hour IOP mean. Melatonin improved RGCs function in advanced glaucoma; N95 amplitude increase correlated positively with RGCs loss. The beneficial effects of melatonin on sleep and mood were greater in advanced glaucoma. Finally, delayed salivary melatonin and Tb phases were observed in MTNR1B G-allele carriers with advanced glaucoma. Combined, these results provide evidence for melatonin efficiency in restoring disrupted circadian rhythms in glaucoma with different effects of melatonin on systemic vs. local circadian rhythms, indicating that a personalized strategy of melatonin administration may further refine its treatment benefits.
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Affiliation(s)
- Denis Gubin
- Department of Biology, Medical University, Tyumen, Russia
- Tyumen Cardiology Research Center, Tomsk National Research Medical Center, Russian Academy of Science, Tomsk, Russia
| | - Vladimir Neroev
- Helmholtz Moscow Research Institute of Eye Diseases, Moscow, Russia
| | | | - Germaine Cornelissen
- Department of Integrated Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Sergei Y Astakhov
- Pavlov First Saint Petersburg State Medical University, St. Petersburg, Russia
| | - Sergey Kolomeichuk
- Laboratory of Genetics, Institute of Biology of the Karelian Science Center of the Russian Academy of Sciences, Petrozavodsk, Russia
| | | | - Yana Kabitskaya
- Center for Genomic Technologies, Northern Trans-Ural State Agricultural University, Tyumen, Russia
| | - Dietmar Weinert
- Institute of Biology/Zoology, Martin Luther University, Halle-Wittenberg, Germany
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Liu H, Prokosch V. Energy Metabolism in the Inner Retina in Health and Glaucoma. Int J Mol Sci 2021; 22:ijms22073689. [PMID: 33916246 PMCID: PMC8036449 DOI: 10.3390/ijms22073689] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/22/2021] [Accepted: 03/29/2021] [Indexed: 02/07/2023] Open
Abstract
Glaucoma, the leading cause of irreversible blindness, is a heterogeneous group of diseases characterized by progressive loss of retinal ganglion cells (RGCs) and their axons and leads to visual loss and blindness. Risk factors for the onset and progression of glaucoma include systemic and ocular factors such as older age, lower ocular perfusion pressure, and intraocular pressure (IOP). Early signs of RGC damage comprise impairment of axonal transport, downregulation of specific genes and metabolic changes. The brain is often cited to be the highest energy-demanding tissue of the human body. The retina is estimated to have equally high demands. RGCs are particularly active in metabolism and vulnerable to energy insufficiency. Understanding the energy metabolism of the inner retina, especially of the RGCs, is pivotal for understanding glaucoma’s pathophysiology. Here we review the key contributors to the high energy demands in the retina and the distinguishing features of energy metabolism of the inner retina. The major features of glaucoma include progressive cell death of retinal ganglions and optic nerve damage. Therefore, this review focuses on the energetic budget of the retinal ganglion cells, optic nerve and the relevant cells that surround them.
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Chen H, Tian A, Wu Y, Li R, Han R, Xu X, Cheng S. HSP70 expression before and after treatment and its clinical value in patients with acute angle-closure glaucoma. Exp Ther Med 2021; 21:253. [PMID: 33603860 DOI: 10.3892/etm.2021.9683] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 11/20/2020] [Indexed: 01/26/2023] Open
Abstract
The present study aimed to explore the clinical role of heat shock protein 70 (HSP70) in patients with acute angle-closure glaucoma (AACG). Seventy-four AACG patients who were admitted to our hospital from April 2017 to April 2019 were enrolled as a study group (SG). A further 70 healthy people undergoing physical examinations during the same period were enrolled as a control group (CG). HSP70 concentration was compared between the two groups, and the clinical value of this protein in AACG was analyzed. HSP70 concentration in SG was significantly lower than that in CG (P<0.050). The sensitivity and specificity of HSP70 for diagnosing AACG were 79.73 and 74.29%, respectively (P<0.001). HSP70 concentration was positively correlated with central anterior chamber depth and peripheral anterior chamber depth, but negatively correlated with anterior angle and intraocular pressure (P<0.001). HSP70 had a relatively satisfactory predictive value for adverse reactions during the treatment (P<0.001). HSP70 concentration was markedly reduced in AACG patients, and its detection had a relatively satisfactory predictive value for AACG. Thus, HSP70 may be a potential and notable indicator for diagnosing and treating glaucoma in the future.
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Affiliation(s)
- Hong Chen
- Department of Glaucoma, Hebei Eye Hospital, Xingtai, Hebei 054000, P.R. China
| | - Aijun Tian
- Department of Glaucoma, Hebei Eye Hospital, Xingtai, Hebei 054000, P.R. China
| | - Yixiang Wu
- Department of Fundus Disease, Hebei Eye Hospital, Xingtai, Hebei 054000, P.R. China
| | - Rongrong Li
- Department of Glaucoma, Hebei Eye Hospital, Xingtai, Hebei 054000, P.R. China
| | - Ruijuan Han
- Department of Glaucoma, Hebei Eye Hospital, Xingtai, Hebei 054000, P.R. China
| | - Xiaowei Xu
- Department of Cataract Surgery,, Hebei Eye Hospital, Xingtai, Hebei 054000, P.R. China
| | - Sumian Cheng
- Department of Glaucoma, Hebei Eye Hospital, Xingtai, Hebei 054000, P.R. China
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31
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Kong AW, Della Santina L, Ou Y. Probing ON and OFF Retinal Pathways in Glaucoma Using Electroretinography. Transl Vis Sci Technol 2020; 9:14. [PMID: 33117606 PMCID: PMC7571283 DOI: 10.1167/tvst.9.11.14] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 09/14/2020] [Indexed: 12/31/2022] Open
Abstract
Glaucoma is a progressive neurodegenerative disease involving damage and eventually death of retinal ganglion cells (RGCs) that comprise the optic nerve. This review summarizes current understanding of specific RGC type vulnerability in glaucoma and how electroretinography (ERG) may provide an objective measure of these functional perturbations. There is building evidence to suggest that ON RGCs, which respond to light increments, may be more resilient to elevated intraocular pressure and glaucoma, whereas OFF RGCs, which respond to light decrements, may be more susceptible. ERG experiments in nonhuman primates and mice have also shown that the ON- and OFF-pathways can be separated using a variety of techniques such as pattern ERG and the photopic negative response. Another ERG paradigm of interest to separate the ON and OFF responses is a flicker stimulus at varying temporal frequencies. Response to lower temporal frequencies is associated with the ON-pathway, and ERG response to higher frequencies is associated with the OFF-pathway. In mice, experimental glaucoma models have shown greater decreases in ERG response at higher frequencies, suggesting that the OFF-pathway is more susceptible. We also summarize current clinical ERG protocols used for glaucoma and discuss innovations for developing new types of stimuli that can further separate the ON- and OFF-pathways. Applying these novel paradigms that distinguish ON- and OFF-pathways may ultimately improve glaucoma diagnostics and monitoring of glaucoma progression.
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Affiliation(s)
- Alan W Kong
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, USA
| | - Luca Della Santina
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, USA
| | - Yvonne Ou
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, USA
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32
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Short-Term Steady-State Pattern Electroretinography Changes Using a Multi-Pressure Dial in Ocular Hypertensive, Glaucoma Suspect, and Mild Open-Angle Glaucoma Patients: A Randomized, Controlled, Prospective, Pilot Study. Ophthalmol Ther 2020; 9:981-992. [PMID: 32939747 PMCID: PMC7708609 DOI: 10.1007/s40123-020-00302-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 09/04/2020] [Indexed: 11/21/2022] Open
Abstract
Introduction This study evaluates the effects of the multi-pressure dial (MPD) on steady-state pattern electroretinography (ss-pERG) parameters. The study is a randomized, controlled, prospective, pilot trial in a private practice setting with ocular hypertensive (OHT), glaucoma suspect, and open-angle glaucoma (OAG) subjects. Methods This study included nine patients (64 ± 9.0 years, nine female) with OHT, glaucoma suspect, or mild OAG. One eye of each subject was randomized to receive negative periocular pressure, while the contralateral eye served as the intrasubject control through the goggle without negative pressure. The Diopsys High Contrast Sensitivity ss-pERG protocol was conducted on both eyes of each subject while wearing the MPD device. Application of negative periocular pressure was set at 50% of baseline intraocular pressure for each study eye. Results Following 2 h of negative periocular pressure application, the difference in MagnitudeD (MagD) from baseline for eyes randomized to receive negative periocular pressure (+ 0.17 versus − 0.26) was statistically significant (p = 0.023). Over the same period, the change in MagD/Magnitude (MagD/Mag ratio) from baseline for eyes randomized to receive negative periocular pressure was also higher (+ 0.14 versus − 0.16), compared to the control eyes, approached significance (p = 0.059). Conclusions Following 2 h of MPD wear, the measured MagD and MagD/Mag ratio improved compared to control, suggesting that negative periocular pressure application to the anterior globe can lead to short-term improvement in one measure of retinal ganglion cell function.
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Intravitreal Co-Administration of GDNF and CNTF Confers Synergistic and Long-Lasting Protection against Injury-Induced Cell Death of Retinal Ganglion Cells in Mice. Cells 2020; 9:cells9092082. [PMID: 32932933 PMCID: PMC7565883 DOI: 10.3390/cells9092082] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 09/03/2020] [Accepted: 09/09/2020] [Indexed: 12/15/2022] Open
Abstract
We have recently demonstrated that neural stem cell-based intravitreal co-administration of glial cell line-derived neurotrophic factor (GDNF) and ciliary neurotrophic factor (CNTF) confers profound protection to injured retinal ganglion cells (RGCs) in a mouse optic nerve crush model, resulting in the survival of ~38% RGCs two months after the nerve lesion. Here, we analyzed whether this neuroprotective effect is long-lasting and studied the impact of the pronounced RGC rescue on axonal regeneration. To this aim, we co-injected a GDNF- and a CNTF-overexpressing neural stem cell line into the vitreous cavity of adult mice one day after an optic nerve crush and determined the number of surviving RGCs 4, 6 and 8 months after the lesion. Remarkably, we found no significant decrease in the number of surviving RGCs between the successive analysis time points, indicating that the combined administration of GDNF and CNTF conferred lifelong protection to injured RGCs. While the simultaneous administration of GDNF and CNTF stimulated pronounced intraretinal axon growth when compared to retinas treated with either factor alone, numbers of regenerating axons in the distal optic nerve stumps were similar in animals co-treated with both factors and animals treated with CNTF only.
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Sladek AL, Nawy S. Ocular Hypertension Drives Remodeling of AMPA Receptors in Select Populations of Retinal Ganglion Cells. Front Synaptic Neurosci 2020; 12:30. [PMID: 32792936 PMCID: PMC7393603 DOI: 10.3389/fnsyn.2020.00030] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 06/25/2020] [Indexed: 12/31/2022] Open
Abstract
AMPA-type glutamate receptors in the CNS are normally impermeable to Ca2+, but the aberrant expression of Ca2+-permeable AMPA receptors (CP-AMPARs) occurs in pathological conditions such as ischemia or epilepsy, or degenerative diseases such as ALS. Here, we show that select populations of retinal ganglion cells (RGCs) similarly express high levels of CP-AMPARs in a mouse model of glaucoma. CP-AMPAR expression increased dramatically in both On sustained alpha and Off transient alpha RGCs, and this increase was prevented by genomic editing of the GluA2 subunit. On sustained alpha RGCs with elevated CP-AMPAR levels displayed profound synaptic depression, which was reduced by selectively blocking CP-AMPARs, buffering Ca2+ with BAPTA, or with the CB1 antagonist AM251, suggesting that depression was mediated by a retrograde transmitter which might be triggered by the influx of Ca2+ through CP-AMPARs. Thus, glaucoma may alter the composition of AMPARs and depress excitatory synaptic input in select populations of RGCs.
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Affiliation(s)
| | - Scott Nawy
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
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35
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Yan W, Peng YR, van Zyl T, Regev A, Shekhar K, Juric D, Sanes JR. Cell Atlas of The Human Fovea and Peripheral Retina. Sci Rep 2020; 10:9802. [PMID: 32555229 PMCID: PMC7299956 DOI: 10.1038/s41598-020-66092-9] [Citation(s) in RCA: 130] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 05/12/2020] [Indexed: 01/28/2023] Open
Abstract
Most irreversible blindness results from retinal disease. To advance our understanding of the etiology of blinding diseases, we used single-cell RNA-sequencing (scRNA-seq) to analyze the transcriptomes of ~85,000 cells from the fovea and peripheral retina of seven adult human donors. Utilizing computational methods, we identified 58 cell types within 6 classes: photoreceptor, horizontal, bipolar, amacrine, retinal ganglion and non-neuronal cells. Nearly all types are shared between the two retinal regions, but there are notable differences in gene expression and proportions between foveal and peripheral cohorts of shared types. We then used the human retinal atlas to map expression of 636 genes implicated as causes of or risk factors for blinding diseases. Many are expressed in striking cell class-, type-, or region-specific patterns. Finally, we compared gene expression signatures of cell types between human and the cynomolgus macaque monkey, Macaca fascicularis. We show that over 90% of human types correspond transcriptomically to those previously identified in macaque, and that expression of disease-related genes is largely conserved between the two species. These results validate the use of the macaque for modeling blinding disease, and provide a foundation for investigating molecular mechanisms underlying visual processing.
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Affiliation(s)
- Wenjun Yan
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, 02138, USA
| | - Yi-Rong Peng
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, 02138, USA
- Department of Ophthalmology, Stein Eye Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Tavé van Zyl
- Department of Ophthalmology, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, 02114, USA
| | - Aviv Regev
- Howard Hughes Medical Institute, Koch Institute of Integrative Cancer Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02140; and Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Karthik Shekhar
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, 02138, USA
- Howard Hughes Medical Institute, Koch Institute of Integrative Cancer Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02140; and Klarman Cell Observatory, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Department of Chemical and Biomolecular Engineering and Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Dejan Juric
- Massachusetts General Hospital Cancer Center, Department of Medicine, Harvard Medical School, Boston, USA
| | - Joshua R Sanes
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, 02138, USA.
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36
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Yang N, Young BK, Wang P, Tian N. The Susceptibility of Retinal Ganglion Cells to Optic Nerve Injury is Type Specific. Cells 2020; 9:cells9030677. [PMID: 32164319 PMCID: PMC7140711 DOI: 10.3390/cells9030677] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/08/2020] [Accepted: 03/09/2020] [Indexed: 12/23/2022] Open
Abstract
Retinal ganglion cell (RGC) death occurs in many eye diseases, such as glaucoma and traumatic optic neuropathy (TON). Increasing evidence suggests that the susceptibility of RGCs varies to different diseases in an RGC type-dependent manner. We previously showed that the susceptibility of several genetically identified RGC types to N-methyl-D-aspartate (NMDA) excitotoxicity differs significantly. In this study, we characterize the susceptibility of the same RGC types to optic nerve crush (ONC). We show that the susceptibility of these RGC types to ONC varies significantly, in which BD-RGCs are the most resistant RGC type while W3-RGCs are the most sensitive cells to ONC. We also show that the survival rates of BD-RGCs and J-RGCs after ONC are significantly higher than their survival rates after NMDA excitotoxicity. These results are consistent with the conclusion that the susceptibility of RGCs to ONC varies in an RGC type-dependent manner. Further, the susceptibilities of the same types of RGCs to ONC and NMDA excitotoxicity are significantly different. These are valuable insights for understanding of the selective susceptibility of RGCs to various pathological insults and the development of a strategy to protect RGCs from death in disease conditions.
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Affiliation(s)
- Ning Yang
- VA Salt Lake City Health Care System, Salt Lake City, UT 84148, USA; (N.Y.); (B.K.Y.); (P.W.)
- Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT 84132, USA
| | - Brent K Young
- VA Salt Lake City Health Care System, Salt Lake City, UT 84148, USA; (N.Y.); (B.K.Y.); (P.W.)
- Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT 84132, USA
- Interdepartmental Neuroscience Program, University of Utah, Salt Lake City, UT 84114, USA
| | - Ping Wang
- VA Salt Lake City Health Care System, Salt Lake City, UT 84148, USA; (N.Y.); (B.K.Y.); (P.W.)
- Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT 84132, USA
| | - Ning Tian
- VA Salt Lake City Health Care System, Salt Lake City, UT 84148, USA; (N.Y.); (B.K.Y.); (P.W.)
- Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT 84132, USA
- Interdepartmental Neuroscience Program, University of Utah, Salt Lake City, UT 84114, USA
- Correspondence: ; Tel.: +01-801-213-2852
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37
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Differential sensitivity of the On and Off visual responses to retinal ischemia. Exp Eye Res 2020; 191:107906. [PMID: 31899251 DOI: 10.1016/j.exer.2019.107906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 12/19/2019] [Accepted: 12/27/2019] [Indexed: 11/22/2022]
Abstract
Retinal ischemia is a common condition that may lead into vision impairment and blindness. In this study, we evaluated changes separately in On and Off visual responses induced by retinal ischemia. To do this, reversible retinal ischemia was induced in anaesthetized rats by increasing the intraocular pressure until the eye fundus became whitish for either 30 or 60 min. Both electroretinogram (ERG) and multiunit neuronal activity in the superior colliculus (SC) were recorded simultaneously for at least 20 min before, during, and after ischemia. In addition, in normal eyes, intravitreal glycine (Gly) injections were performed to further investigate the mechanisms involved in this process. We found that collicular Off responses were more sensitive to ischemia than On responses. The Off response was the first one to decay at the time ischemia was induced and the last to recover after blood reperfusion. The duration of ischemia also differentially affected both responses. After 30 min of ischemia, 14% of SC recordings failed to recover Off responses. After 1 h of ischemia, the percentage of recordings that failed to recover Off responses increased to 50%. Post-ischemic ERGs remained unaltered in all cases. Intravitreal Gly injections caused suppression of Off responses in the SC. Higher doses caused suppression of both On and Off responses in the SC but with no effect on the ERG at the doses tested. In summary, Off responses were more sensitive than On responses to ischemia suggesting that different mechanisms drive the two types of responses. The recovery of transitory ischemia was not complete in the SC responses whereas the ERG remained unaltered, suggesting that retinal damage produced by ischemia is more prominent in ganglion cells. Our results provide critical information for understanding ischemia repercussions and visual processing in the early visual system.
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38
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Wang AY, Lee PY, Bui BV, Jobling AI, Greferath U, Brandli A, Dixon MA, Findlay Q, Fletcher EL, Vessey KA. Potential mechanisms of retinal ganglion cell type-specific vulnerability in glaucoma. Clin Exp Optom 2019; 103:562-571. [PMID: 31838755 DOI: 10.1111/cxo.13031] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 10/17/2019] [Accepted: 11/16/2019] [Indexed: 12/22/2022] Open
Abstract
Glaucoma is a neurodegenerative disease characterised by progressive damage to the retinal ganglion cells (RGCs), the output neurons of the retina. RGCs are a heterogenous class of retinal neurons which can be classified into multiple types based on morphological, functional and genetic characteristics. This review examines the body of evidence supporting type-specific vulnerability of RGCs in glaucoma and explores potential mechanisms by which this might come about. Studies of donor tissue from glaucoma patients have generally noted greater vulnerability of larger RGC types. Models of glaucoma induced in primates, cats and mice also show selective effects on RGC types - particularly OFF RGCs. Several mechanisms may contribute to type-specific vulnerability, including differences in the expression of calcium-permeable receptors (for example pannexin-1, P2X7, AMPA and transient receptor potential vanilloid receptors), the relative proximity of RGCs and their dendrites to blood supply in the inner plexiform layer, as well as differing metabolic requirements of RGC types. Such differences may make certain RGCs more sensitive to intraocular pressure elevation and its associated biomechanical and vascular stress. A greater understanding of selective RGC vulnerability and its underlying causes will likely reveal a rich area of investigation for potential treatment targets.
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Affiliation(s)
- Anna Ym Wang
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Pei Ying Lee
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Australia
| | - Andrew I Jobling
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Ursula Greferath
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Alice Brandli
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Michael A Dixon
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Quan Findlay
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Kirstan A Vessey
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
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39
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Tribble JR, Vasalauskaite A, Redmond T, Young RD, Hassan S, Fautsch MP, Sengpiel F, Williams PA, Morgan JE. Midget retinal ganglion cell dendritic and mitochondrial degeneration is an early feature of human glaucoma. Brain Commun 2019; 1:fcz035. [PMID: 31894207 PMCID: PMC6928391 DOI: 10.1093/braincomms/fcz035] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/29/2019] [Accepted: 11/01/2019] [Indexed: 12/31/2022] Open
Abstract
Glaucoma is characterized by the progressive dysfunction and loss of retinal ganglion cells. However, the earliest degenerative events that occur in human glaucoma are relatively unknown. Work in animal models has demonstrated that retinal ganglion cell dendrites remodel and atrophy prior to the loss of the cell soma. Whether this occurs in human glaucoma has yet to be elucidated. Serial block face scanning electron microscopy is well established as a method to determine neuronal connectivity at high resolution but so far has only been performed in normal retina from animal models. To assess the structure-function relationship of early human glaucomatous neurodegeneration, regions of inner retina assessed to have none-to-moderate loss of retinal ganglion cell number were processed using serial block face scanning electron microscopy (n = 4 normal retinas, n = 4 glaucoma retinas). This allowed detailed 3D reconstruction of retinal ganglion cells and their intracellular components at a nanometre scale. In our datasets, retinal ganglion cell dendrites degenerate early in human glaucoma, with remodelling and redistribution of the mitochondria. We assessed the relationship between visual sensitivity and retinal ganglion cell density and discovered that this only partially conformed to predicted models of structure-function relationships, which may be affected by these early neurodegenerative changes. In this study, human glaucomatous retinal ganglion cells demonstrate compartmentalized degenerative changes as observed in animal models. Importantly, in these models, many of these changes have been demonstrated to be reversible, increasing the likelihood of translation to viable therapies for human glaucoma.
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Affiliation(s)
- James R Tribble
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ Wales, UK
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 112 82 Stockholm, Sweden
| | | | - Tony Redmond
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ Wales, UK
| | - Robert D Young
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ Wales, UK
| | - Shoaib Hassan
- School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XW Wales, UK
| | | | - Frank Sengpiel
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX Wales, UK
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, 112 82 Stockholm, Sweden
| | - James E Morgan
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, CF24 4HQ Wales, UK
- School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XW Wales, UK
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40
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Lani R, Dias MS, Abreu CA, Araújo VG, Gonçalo T, Nascimento-Dos-Santos G, Dantas AM, Allodi S, Fiorani M, Petrs-Silva H, Linden R. A subacute model of glaucoma based on limbal plexus cautery in pigmented rats. Sci Rep 2019; 9:16286. [PMID: 31705136 PMCID: PMC6841973 DOI: 10.1038/s41598-019-52500-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 10/16/2019] [Indexed: 12/17/2022] Open
Abstract
Glaucoma is a neurodegenerative disorder characterized by the progressive functional impairment and degeneration of the retinal ganglion cells (RGCs) and their axons, and is the leading cause of irreversible blindness worldwide. Current management of glaucoma is based on reduction of high intraocular pressure (IOP), one of its most consistent risk factors, but the disease proceeds in almost half of the patients despite such treatments. Several experimental models of glaucoma have been developed in rodents, most of which present shortcomings such as high surgical invasiveness, slow learning curves, damage to the transparency of the optic media which prevents adequate functional assessment, and variable results. Here we describe a novel and simple method to induce ocular hypertension in pigmented rats, based on low-temperature cauterization of the whole circumference of the limbal vascular plexus, a major component of aqueous humor drainage and easily accessible for surgical procedures. This simple, low-cost and efficient method produced a reproducible subacute ocular hypertension with full clinical recovery, followed by a steady loss of retinal ganglion cells and optic axons, accompanied by functional changes detected both by electrophysiological and behavioral methods.
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Affiliation(s)
- Rafael Lani
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
| | - Mariana S Dias
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Carla Andreia Abreu
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Victor G Araújo
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Thais Gonçalo
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | | | - Silvana Allodi
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Mario Fiorani
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Hilda Petrs-Silva
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
| | - Rafael Linden
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
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Ohlemacher SK, Langer KB, Fligor CM, Feder EM, Edler MC, Meyer JS. Advances in the Differentiation of Retinal Ganglion Cells from Human Pluripotent Stem Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1186:121-140. [PMID: 31654388 DOI: 10.1007/978-3-030-28471-8_5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Human pluripotent stem cell (hPSC) technology has revolutionized the field of biology through the unprecedented ability to study the differentiation of human cells in vitro. In the past decade, hPSCs have been applied to study development, model disease, develop drugs, and devise cell replacement therapies for numerous biological systems. Of particular interest is the application of this technology to study and treat optic neuropathies such as glaucoma. Retinal ganglion cells (RGCs) are the primary cell type affected in these diseases, and once lost, they are unable to regenerate in adulthood. This necessitates the development of strategies to study the mechanisms of degeneration as well as develop translational therapeutic approaches to treat early- and late-stage disease progression. Numerous protocols have been established to derive RGCs from hPSCs, with the ability to generate large populations of human RGCs for translational applications. In this review, the key applications of hPSCs within the retinal field are described, including the use of these cells as developmental models, disease models, drug development, and finally, cell replacement therapies. In greater detail, the current report focuses on the differentiation of hPSC-derived RGCs and the many unique characteristics associated with these cells in vitro including their genetic identifiers, their electrophysiological activity, and their morphological maturation. Also described is the current progress in the use of patient-specific hPSCs to study optic neuropathies affecting RGCs, with emphasis on the use of these RGCs for studying disease mechanisms and pathogenesis, drug screening, and cell replacement therapies in future studies.
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Affiliation(s)
- Sarah K Ohlemacher
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA
| | - Kirstin B Langer
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA
| | - Clarisse M Fligor
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA
| | - Elyse M Feder
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA
| | - Michael C Edler
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA.,Department of Medical and Molecular Genetics, Indiana University, Indianapolis, IN, USA
| | - Jason S Meyer
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA. .,Department of Medical and Molecular Genetics, Indiana University, Indianapolis, IN, USA. .,Stark Neurosciences Research Institute, Indiana University, Indianapolis, IN, USA.
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Bhandari A, Smith JC, Zhang Y, Jensen AA, Reid L, Goeser T, Fan S, Ghate D, Van Hook MJ. Early-Stage Ocular Hypertension Alters Retinal Ganglion Cell Synaptic Transmission in the Visual Thalamus. Front Cell Neurosci 2019; 13:426. [PMID: 31607867 PMCID: PMC6761307 DOI: 10.3389/fncel.2019.00426] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 09/04/2019] [Indexed: 12/21/2022] Open
Abstract
Axonopathy is a hallmark of many neurodegenerative diseases including glaucoma, where elevated intraocular pressure (ocular hypertension, OHT) stresses retinal ganglion cell (RGC) axons as they exit the eye and form the optic nerve. OHT causes early changes in the optic nerve such as axon atrophy, transport inhibition, and gliosis. Importantly, many of these changes appear to occur prior to irreversible neuronal loss, making them promising points for early diagnosis of glaucoma. It is unknown whether OHT has similarly early effects on the function of RGC output to the brain. To test this possibility, we elevated eye pressure in mice by anterior chamber injection of polystyrene microbeads. Five weeks post-injection, bead-injected eyes showed a modest RGC loss in the peripheral retina, as evidenced by RBPMS antibody staining. Additionally, we observed reduced dendritic complexity and lower spontaneous spike rate of On-αRGCs, targeted for patch clamp recording and dye filling using a Opn4-Cre reporter mouse line. To determine the influence of OHT on retinal projections to the brain, we expressed Channelrhodopsin-2 (ChR2) in melanopsin-expressing RGCs by crossing the Opn4-Cre mouse line with a ChR2-reporter mouse line and recorded post-synaptic responses in thalamocortical relay neurons in the dorsal lateral geniculate nucleus (dLGN) of the thalamus evoked by stimulation with 460 nm light. The use of a Opn4-Cre reporter system allowed for expression of ChR2 in a narrow subset of RGCs responsible for image-forming vision in mice. Five weeks following OHT induction, paired pulse and high-frequency stimulus train experiments revealed that presynaptic vesicle release probability at retinogeniculate synapses was elevated. Additionally, miniature synaptic current frequency was slightly reduced in brain slices from OHT mice and proximal dendrites of post-synaptic dLGN relay neurons, assessed using a Sholl analysis, showed a reduced complexity. Strikingly, these changes occurred prior to major loss of RGCs labeled with the Opn4-Cre mouse, as indicated by immunofluorescence staining of ChR2-expressing retinal neurons. Thus, OHT leads to pre- and post-synaptic functional and structural changes at retinogeniculate synapses. Along with RGC dendritic remodeling and optic nerve transport changes, these retinogeniculate synaptic changes are among the earliest signs of glaucoma.
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Affiliation(s)
- Ashish Bhandari
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Jennie C Smith
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Yang Zhang
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States.,Creighton University School of Medicine, Omaha, NE, United States.,Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Aaron A Jensen
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Lisa Reid
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Toni Goeser
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Shan Fan
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Deepta Ghate
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Matthew J Van Hook
- Department of Ophthalmology and Visual Sciences, Stanley M. Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
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Melanopsin +RGCs Are fully Resistant to NMDA-Induced Excitotoxicity. Int J Mol Sci 2019; 20:ijms20123012. [PMID: 31226772 PMCID: PMC6627747 DOI: 10.3390/ijms20123012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 06/11/2019] [Accepted: 06/18/2019] [Indexed: 12/13/2022] Open
Abstract
We studied short- and long-term effects of intravitreal injection of N-methyl-d-aspartate (NMDA) on melanopsin-containing (m+) and non-melanopsin-containing (Brn3a+) retinal ganglion cells (RGCs). In adult SD-rats, the left eye received a single intravitreal injection of 5µL of 100nM NMDA. At 3 and 15 months, retinal thickness was measured in vivo using Spectral Domain-Optical Coherence Tomography (SD-OCT). Ex vivo analyses were done at 3, 7, or 14 days or 15 months after damage. Whole-mounted retinas were immunolabelled for brain-specific homeobox/POU domain protein 3A (Brn3a) and melanopsin (m), the total number of Brn3a+RGCs and m+RGCs were quantified, and their topography represented. In control retinas, the mean total numbers of Brn3a+RGCs and m+RGCs were 78,903 ± 3572 and 2358 ± 144 (mean ± SD; n = 10), respectively. In the NMDA injected retinas, Brn3a+RGCs numbers diminished to 49%, 28%, 24%, and 19%, at 3, 7, 14 days, and 15 months, respectively. There was no further loss between 7 days and 15 months. The number of immunoidentified m+RGCs decreased significantly at 3 days, recovered between 3 and 7 days, and were back to normal thereafter. OCT measurements revealed a significant thinning of the left retinas at 3 and 15 months. Intravitreal injections of NMDA induced within a week a rapid loss of 72% of Brn3a+RGCs, a transient downregulation of melanopsin expression (but not m+RGC death), and a thinning of the inner retinal layers.
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Christensen I, Lu B, Yang N, Huang K, Wang P, Tian N. The Susceptibility of Retinal Ganglion Cells to Glutamatergic Excitotoxicity Is Type-Specific. Front Neurosci 2019; 13:219. [PMID: 30930737 PMCID: PMC6429039 DOI: 10.3389/fnins.2019.00219] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 02/26/2019] [Indexed: 12/17/2022] Open
Abstract
Retinal ganglion cells (RGCs) are the only output neurons that conduct visual signals from the eyes to the brain. RGC degeneration occurs in many retinal diseases leading to blindness and increasing evidence suggests that RGCs are susceptible to various injuries in a type-specific manner. Glutamate excitotoxicity is the pathological process by which neurons are damaged and killed by excessive stimulation of glutamate receptors and it plays a central role in the death of neurons in many CNS and retinal diseases. The purpose of this study is to characterize the susceptibility of genetically identified RGC types to the excitotoxicity induced by N-methyl-D-aspartate (NMDA). We show that the susceptibility of different types of RGCs to NMDA excitotoxicity varies significantly, in which the αRGCs are the most resistant type of RGCs to NMDA excitotoxicity while the J-RGCs are the most sensitive cells to NMDA excitotoxicity. These results strongly suggest that the differences in the genetic background of RGC types might provide valuable insights for understanding the selective susceptibility of RGCs to pathological insults and the development of a strategy to protect RGCs from death in disease conditions. In addition, our results show that RGCs lose dendrites before death and the sequence of the morphological and molecular events during RGC death suggests that the initial insult of NMDA excitotoxicity might set off a cascade of events independent of the primary insults. However, the kinetics of dendritic retraction in RGCs does not directly correlate to the susceptibility of type-specific RGC death.
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Affiliation(s)
- Ian Christensen
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Bo Lu
- VA Salt Lake City Health Care System, Salt Lake City, UT, United States.,Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Ning Yang
- VA Salt Lake City Health Care System, Salt Lake City, UT, United States.,Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Kevin Huang
- VA Salt Lake City Health Care System, Salt Lake City, UT, United States.,Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Ping Wang
- VA Salt Lake City Health Care System, Salt Lake City, UT, United States.,Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Ning Tian
- VA Salt Lake City Health Care System, Salt Lake City, UT, United States.,Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, United States
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45
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Mayer C, Bruehl C, Salt EL, Diem R, Draguhn A, Fairless R. Selective Vulnerability of αOFF Retinal Ganglion Cells during Onset of Autoimmune Optic Neuritis. Neuroscience 2018; 393:258-272. [PMID: 30075244 DOI: 10.1016/j.neuroscience.2018.07.040] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/04/2018] [Accepted: 07/23/2018] [Indexed: 12/27/2022]
Abstract
Retinal ganglion cells (RGCs), a diverse body of neurons which relay visual signals from the retina to the higher processing regions of the brain, are susceptible to neurodegenerative processes in several diseases affecting the retina. Previous evidence shows that RGCs are damaged at early stages of autoimmune optic neuritis (AON), prior to subsequent degeneration of the optic nerve. In order to study cell type-specific vulnerability of RGCs we performed immunohistochemical and patch-clamp electrophysiological analyses of RGCs following induction of AON using the experimental autoimmune encephalomyelitis model in Brown Norway rats. We report that αRGCs are more susceptible to degeneration than the global RGC population as a whole, with functional and structural changes beginning even prior to demyelination and inflammatory infiltration of the optic nerve (where the RGC axons reside). Functional classification of αRGCs into OFF-sustained, OFF-transient and ON-sustained subtypes revealed that αOFF RGCs (both sustained and transient subtypes) are more vulnerable than αON RGCs, as indicated by reductions in light-evoked post-synaptic currents and retraction of dendritic arbours. Classification of neuronal susceptibility is a first step in furthering our understanding of what underlies a neuron's vulnerability to degenerative processes, necessary for the future development of effective neuroprotective strategies.
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Affiliation(s)
- Christina Mayer
- Department of Neurology, University Clinic Heidelberg, 69120 Heidelberg, Germany
| | - Claus Bruehl
- Institute of Physiology and Pathophysiology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Emma L Salt
- Department of Neurology, University Clinic Heidelberg, 69120 Heidelberg, Germany
| | - Ricarda Diem
- Department of Neurology, University Clinic Heidelberg, 69120 Heidelberg, Germany
| | - Andreas Draguhn
- Institute of Physiology and Pathophysiology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Richard Fairless
- Department of Neurology, University Clinic Heidelberg, 69120 Heidelberg, Germany.
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46
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Wen X, Cahill AL, Barta C, Thoreson WB, Nawy S. Elevated Pressure Increases Ca 2+ Influx Through AMPA Receptors in Select Populations of Retinal Ganglion Cells. Front Cell Neurosci 2018; 12:162. [PMID: 29950974 PMCID: PMC6008319 DOI: 10.3389/fncel.2018.00162] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 05/25/2018] [Indexed: 12/14/2022] Open
Abstract
The predominate type of AMPA receptor expressed in the CNS is impermeable to Ca2+ (CI-AMPAR). However, some AMPA receptors are permeable to Ca2+ (CP-AMPAR) and play important roles in development, plasticity and disease. In the retina, ganglion cells (RGCs) are targets of disease including glaucoma and diabetic retinopathy, but there are many types of RGCs and not all types are targeted equally. In the present study, we sought to determine if there are differences in expression of AMPARs amongst RGC subtypes, and if these differences might contribute to differential vulnerability in a model of stress. Using cultured RGCs we first show that acute exposure to elevated pressure increased expression of Ca2+-permeable AMPA receptors (CP-AMPARs) in some, but not all classes of RGCs. When RGCs were sampled without regard to subtype, AMPA currents, measured using patch clamp recording, were blocked by the CP-AMPAR blocker PhTX-74 to a greater extent in pressure-treated RGCs vs. control. Furthermore, imaging experiments revealed an increase in Ca2+ influx during AMPA application in pressure-treated RGCs. However, examination of specific RGC subtypes using reporter lines revealed striking differences in both baseline AMPAR composition and modulation of this baseline composition by stress. Notably, ON alpha RGCs identified using the Opn4 mouse line and immunohistochemistry, had low expression of CP-AMPARs. Conversely, an ON-OFF direction selective RGC and putative OFF alpha RGC each expressed high levels of CP-AMPARs. These differences between RGC subtypes were also observed in RGCs from whole retina. Elevated pressure further lowered expression of CP-AMPARs in ON alpha RGCs, but raised expression in ON-OFF and OFF RGCs. Changes in CP-AMPAR expression following challenge with elevated pressure were correlated with RGC survival: ON alpha RGCs were unaffected by application of pressure, while the number of putative OFF alpha RGCs declined by approximately 50% following challenge with pressure. Differences in expression of CP-AMPARs between RGC subtypes may form the underpinnings for subtype-specific synaptic plasticity. Furthermore, the differential responses of these RGC subtypes to elevated pressure may contribute to the reported resistance of ON alpha, and susceptibility of OFF and ON-OFF RGCs to injury in models of glaucoma.
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Affiliation(s)
- Xiangyi Wen
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, United States
| | - Asia L Cahill
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Cody Barta
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States
| | - Wallace B Thoreson
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, United States
| | - Scott Nawy
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, United States
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47
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Affiliation(s)
- Mohammadali Almasieh
- Departments of Ophthalmology and Neurology, McGill University, Montreal H4A 3S5, Canada
- Maisonneuve-Rosemont Hospital Research Center and Department of Ophthalmology, University of Montreal, Montreal H1T 2M4, Canada
| | - Leonard A. Levin
- Departments of Ophthalmology and Neurology, McGill University, Montreal H4A 3S5, Canada
- Maisonneuve-Rosemont Hospital Research Center and Department of Ophthalmology, University of Montreal, Montreal H1T 2M4, Canada
- Department of Ophthalmology and Visual Science, University of Wisconsin, Madison, Wisconsin 53706
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48
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Puyang Z, Gong HQ, He SG, Troy JB, Liu X, Liang PJ. Different functional susceptibilities of mouse retinal ganglion cell subtypes to optic nerve crush injury. Exp Eye Res 2017; 162:97-103. [PMID: 28629926 DOI: 10.1016/j.exer.2017.06.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/28/2016] [Accepted: 06/16/2017] [Indexed: 10/19/2022]
Abstract
In optic neuropathies, the progressive deterioration of retinal ganglion cell (RGC) function leads to irreversible vision loss. Increasing experimental evidence suggests differing susceptibility for RGC functional subtypes. Here with multi-electrode array recordings, RGC functional loss was characterized at multiple time points in a mouse model of optic nerve crush. Firing rate, latency of response and receptive field size were analyzed for ON, OFF and ON-OFF RGCs separately. It was observed that responses and receptive fields of OFF cells were impaired earlier than ON cells after the injury. For the ON-OFF cells, the OFF component of response was also more susceptible to optic nerve injury than the ON component. Moreover, more ON transient cells survived than ON sustained cells post the crush, implying a diversified vulnerability for ON cells. Together, these data support the contention that RGCs' functional degeneration in optic nerve injury is subtype dependent, a fact that needs to be considered when developing treatments of glaucomatous retinal ganglion cell degeneration and other optic neuropathies.
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Affiliation(s)
- Zhen Puyang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hai-Qing Gong
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shi-Gang He
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - John B Troy
- Department of Biomedical Engineering, Robert R. McCormick School of Engineering and Applied Science, Northwestern University, Evanston, IL 60208, USA
| | - Xiaorong Liu
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208, USA.
| | - Pei-Ji Liang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
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49
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Elevated IOP alters the space-time profiles in the center and surround of both ON and OFF RGCs in mouse. Proc Natl Acad Sci U S A 2017; 114:8859-8864. [PMID: 28760976 DOI: 10.1073/pnas.1706994114] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Glaucoma is a leading cause of blindness worldwide, and is characterized by progressive retinal ganglion cell (RGC) death. An experimental model of glaucoma has been established by elevating the intraocular pressure (IOP) via microbead occlusion of ocular fluid outflow in mice. Studies in this model have found visual dysfunction that varied with adaptational state, occurred before anatomical changes, and affected OFF RGCs more than ON RGCs. These results indicate subtle alterations in the underlying retinal circuitry that could help identify disease before irreversible RGC changes. Therefore, we looked at how RGC function was altered with elevated IOP under both photopic and scotopic conditions. We first found that responses to light offset are diminished with IOP elevation along with a concomitant decrease in receptive field center size for OFF RGCs. In addition, the antagonistic surround strength and size was reduced in ON RGCs. Furthermore, elevation of IOP significantly accelerated the photopic temporal tuning of RGC center responses in both ON and OFF RGCs. We found that some of the IOP-induced functional changes to OFF RGCs relied on ON cross-over pathways, indicating dysfunction in inner retinal circuitry. Overall, these results suggest that IOP alters multiple functions in the retina depending on the adaptational state. They provide a basis for designing multiple functional tests for early detection of glaucoma and for circuit-specific therapeutic targets in treatment of this blinding disease.
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50
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Inman DM, Harun-Or-Rashid M. Metabolic Vulnerability in the Neurodegenerative Disease Glaucoma. Front Neurosci 2017; 11:146. [PMID: 28424571 PMCID: PMC5371671 DOI: 10.3389/fnins.2017.00146] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/08/2017] [Indexed: 12/14/2022] Open
Abstract
Axons can be several orders of magnitude longer than neural somas, presenting logistical difficulties in cargo trafficking and structural maintenance. Keeping the axon compartment well supplied with energy also presents a considerable challenge; even seemingly subtle modifications of metabolism can result in functional deficits and degeneration. Axons require a great deal of energy, up to 70% of all energy used by a neuron, just to maintain the resting membrane potential. Axonal energy, in the form of ATP, is generated primarily through oxidative phosphorylation in the mitochondria. In addition, glial cells contribute metabolic intermediates to axons at moments of high activity or according to need. Recent evidence suggests energy disruption is an early contributor to pathology in a wide variety of neurodegenerative disorders characterized by axonopathy. However, the degree to which the energy disruption is intrinsic to the axon vs. associated glia is not clear. This paper will review the role of energy availability and utilization in axon degeneration in glaucoma, a chronic axonopathy of the retinal projection.
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Affiliation(s)
- Denise M Inman
- Department of Pharmaceutical Sciences, Northeast Ohio Medical UniversityRootstown, OH, USA
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