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Beaver D, Limnios IJ. A treatment within sight: challenges in the development of stem cell-derived photoreceptor therapies for retinal degenerative diseases. FRONTIERS IN TRANSPLANTATION 2023; 2:1130086. [PMID: 38993872 PMCID: PMC11235385 DOI: 10.3389/frtra.2023.1130086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 09/07/2023] [Indexed: 07/13/2024]
Abstract
Stem cell therapies can potentially treat various retinal degenerative diseases, including age-related macular degeneration (AMD) and inherited retinal diseases like retinitis pigmentosa. For these diseases, transplanted cells may include stem cell-derived retinal pigmented epithelial (RPE) cells, photoreceptors, or a combination of both. Although stem cell-derived RPE cells have progressed to human clinical trials, therapies using photoreceptors and other retinal cell types are lagging. In this review, we discuss the potential use of human pluripotent stem cell (hPSC)-derived photoreceptors for the treatment of retinal degeneration and highlight the progress and challenges for their efficient production and clinical application in regenerative medicine.
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Affiliation(s)
- Davinia Beaver
- Clem Jones Centre for Regenerative Medicine, Bond University, Gold Coast, QL, Australia
| | - Ioannis Jason Limnios
- Clem Jones Centre for Regenerative Medicine, Bond University, Gold Coast, QL, Australia
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2
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Almasri RM, Ladouceur F, Mawad D, Esrafilzadeh D, Firth J, Lehmann T, Poole-Warren LA, Lovell NH, Al Abed A. Emerging trends in the development of flexible optrode arrays for electrophysiology. APL Bioeng 2023; 7:031503. [PMID: 37692375 PMCID: PMC10491464 DOI: 10.1063/5.0153753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 08/08/2023] [Indexed: 09/12/2023] Open
Abstract
Optical-electrode (optrode) arrays use light to modulate excitable biological tissues and/or transduce bioelectrical signals into the optical domain. Light offers several advantages over electrical wiring, including the ability to encode multiple data channels within a single beam. This approach is at the forefront of innovation aimed at increasing spatial resolution and channel count in multichannel electrophysiology systems. This review presents an overview of devices and material systems that utilize light for electrophysiology recording and stimulation. The work focuses on the current and emerging methods and their applications, and provides a detailed discussion of the design and fabrication of flexible arrayed devices. Optrode arrays feature components non-existent in conventional multi-electrode arrays, such as waveguides, optical circuitry, light-emitting diodes, and optoelectronic and light-sensitive functional materials, packaged in planar, penetrating, or endoscopic forms. Often these are combined with dielectric and conductive structures and, less frequently, with multi-functional sensors. While creating flexible optrode arrays is feasible and necessary to minimize tissue-device mechanical mismatch, key factors must be considered for regulatory approval and clinical use. These include the biocompatibility of optical and photonic components. Additionally, material selection should match the operating wavelength of the specific electrophysiology application, minimizing light scattering and optical losses under physiologically induced stresses and strains. Flexible and soft variants of traditionally rigid photonic circuitry for passive optical multiplexing should be developed to advance the field. We evaluate fabrication techniques against these requirements. We foresee a future whereby established telecommunications techniques are engineered into flexible optrode arrays to enable unprecedented large-scale high-resolution electrophysiology systems.
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Affiliation(s)
- Reem M. Almasri
- Graduate School of Biomedical Engineering, UNSW, Sydney, NSW 2052, Australia
| | | | - Damia Mawad
- School of Materials Science and Engineering, UNSW, Sydney, NSW 2052, Australia
| | - Dorna Esrafilzadeh
- Graduate School of Biomedical Engineering, UNSW, Sydney, NSW 2052, Australia
| | - Josiah Firth
- Australian National Fabrication Facility, UNSW, Sydney, NSW 2052, Australia
| | - Torsten Lehmann
- School of Electrical Engineering and Telecommunications, UNSW, Sydney, NSW 2052, Australia
| | | | | | - Amr Al Abed
- Graduate School of Biomedical Engineering, UNSW, Sydney, NSW 2052, Australia
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Han IC, Bohrer LR, Gibson-Corley KN, Wiley LA, Shrestha A, Harman BE, Jiao C, Sohn EH, Wendland R, Allen BN, Worthington KS, Mullins RF, Stone EM, Tucker BA. Biocompatibility of Human Induced Pluripotent Stem Cell-Derived Retinal Progenitor Cell Grafts in Immunocompromised Rats. Cell Transplant 2022; 31:9636897221104451. [PMID: 35758274 PMCID: PMC9247396 DOI: 10.1177/09636897221104451] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Loss of photoreceptor cells is a primary feature of inherited retinal degenerative disorders including age-related macular degeneration and retinitis pigmentosa. To restore vision in affected patients, photoreceptor cell replacement will be required. The ideal donor cells for this application are induced pluripotent stem cells (iPSCs) because they can be derived from and transplanted into the same patient obviating the need for long-term immunosuppression. A major limitation for retinal cell replacement therapy is donor cell loss associated with simple methods of cell delivery such as subretinal injections of bolus cell suspensions. Transplantation with supportive biomaterials can help maintain cellular integrity, increase cell survival, and encourage proper cellular alignment and improve integration with the host retina. Using a pig model of retinal degeneration, we recently demonstrated that polycaprolactone (PCL) scaffolds fabricated with two photon lithography have excellent local and systemic tolerability. In this study, we describe rapid photopolymerization-mediated production of PCL-based bioabsorbable scaffolds, a technique for loading iPSC-derived retinal progenitor cells onto the scaffold, methods of surgical transplantation in an immunocompromised rat model and tolerability of the subretinal grafts at 1, 3, and 6 months of follow-up (n = 150). We observed no local or systemic toxicity, nor did we observe any tumor formation despite extensive clinical evaluation, clinical chemistry, hematology, gross tissue examination and detailed histopathology. Demonstrating the local and systemic compatibility of biodegradable scaffolds carrying human iPSC-derived retinal progenitor cells is an important step toward clinical safety trials of this approach in humans.
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Affiliation(s)
- Ian C Han
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Laura R Bohrer
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | | | - Luke A Wiley
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Arwin Shrestha
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Brynnon E Harman
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Chunhua Jiao
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Elliott H Sohn
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Rion Wendland
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA.,Department of Biomedical Engineering, College of Engineering, University of Iowa, Iowa City, IA, USA
| | - Brittany N Allen
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA.,Department of Biomedical Engineering, College of Engineering, University of Iowa, Iowa City, IA, USA
| | - Kristan S Worthington
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA.,Department of Biomedical Engineering, College of Engineering, University of Iowa, Iowa City, IA, USA
| | - Robert F Mullins
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Edwin M Stone
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Budd A Tucker
- Institute for Vision Research, University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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4
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Xu S, Zhang P, Zhang M, Wang X, Li G, Xu G, Ni Y. Synaptic changes and the response of microglia in a light-induced photoreceptor degeneration model. Mol Vis 2021; 27:206-220. [PMID: 33967574 PMCID: PMC8100860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 04/29/2021] [Indexed: 11/15/2022] Open
Abstract
Purpose To explore synaptic changes and the response of microglia in a light-induced photoreceptor degeneration model. Methods Sprague-Dawley rats were euthanized 1 h, 1 day, 3 days, 7 days, and 14 days after being exposed to intense blue light for 24 h. Hematoxylin and eosin (H&E) and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining were used to evaluate changes in the outer nuclear layer (ONL). Transmission electron microscopy (TEM) was applied to observe the ultrastructural changes in the synapses between the photoreceptors and second-order neurons. Western blotting was conducted to evaluate specific proteins, including postsynaptic density-95 (PSD-95), metabotropic glutamate receptor 6 (mGluR6), synapsin I, and synaptophysin. Immunofluorescence of CD11b and PKC-α or mGluR6 was used to explore the spatial relationships between microglial processes and synaptic elements. Immunoelectron microscopy of PSD-95 was performed to further confirm its engulfment of synaptic materials. Results H&E and TUNEL staining showed that the thickness of the ONL decreased markedly, and the number of apoptotic photoreceptors peaked at day 1. TEM revealed darkened photoreceptor terminals and that ribbons of them were floating in the cytoplasm, coinciding with the downregulation of PSD-95 and mGluR6. Downstream synaptic protein synapsin I and synaptophysin exhibited upregulation in the inner plexiform layer. Activated microglia migrated to the outer retina, and their processes were found in close proximity to synapses in the outer plexiform layer under light and electron microscopy levels. Double immunostaining of CD11b and mGluR6 showed colocalization. PSD-95-immunoreactive electron-dense materials were observed inside the microglia suggesting engulfment of synaptic components. Conclusions The study showed that there are early synaptic impairment and late compensatory changes in downstream synapses in this photic injury model. Activated microglia touched and directly engulfed synaptic materials. Microglia may play a role or a partial role in synaptic changes.
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Affiliation(s)
- Sisi Xu
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China,Key NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Peijun Zhang
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China,Key NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Meng Zhang
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China,Key NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Xin Wang
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China,Key NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Gang Li
- Research Center, Eye & ENT Hospital of Fudan University, Shanghai, China
| | - Gezhi Xu
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China,Key NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Yingqin Ni
- Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China,Key NHC Key Laboratory of Myopia (Fudan University); Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
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LaVail MM, Nishikawa S, Steinberg RH, Naash MI, Duncan JL, Trautmann N, Matthes MT, Yasumura D, Lau-Villacorta C, Chen J, Peterson WM, Yang H, Flannery JG. Phenotypic characterization of P23H and S334ter rhodopsin transgenic rat models of inherited retinal degeneration. Exp Eye Res 2018; 167:56-90. [PMID: 29122605 PMCID: PMC5811379 DOI: 10.1016/j.exer.2017.10.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/25/2017] [Accepted: 10/31/2017] [Indexed: 02/07/2023]
Abstract
We produced 8 lines of transgenic (Tg) rats expressing one of two different rhodopsin mutations in albino Sprague-Dawley (SD) rats. Three lines were generated with a proline to histidine substitution at codon 23 (P23H), the most common autosomal dominant form of retinitis pigmentosa in the United States. Five lines were generated with a termination codon at position 334 (S334ter), resulting in a C-terminal truncated opsin protein lacking the last 15 amino acid residues and containing all of the phosphorylation sites involved in rhodopsin deactivation, as well as the terminal QVAPA residues important for rhodopsin deactivation and trafficking. The rates of photoreceptor (PR) degeneration in these models vary in proportion to the ratio of mutant to wild-type rhodopsin. The models have been widely studied, but many aspects of their phenotypes have not been described. Here we present a comprehensive study of the 8 Tg lines, including the time course of PR degeneration from the onset to one year of age, retinal structure by light and electron microscopy (EM), hemispheric asymmetry and gradients of rod and cone degeneration, rhodopsin content, gene dosage effect, rapid activation and invasion of the outer retina by presumptive microglia, rod outer segment disc shedding and phagocytosis by the retinal pigmented epithelium (RPE), and retinal function by the electroretinogram (ERG). The biphasic nature of PR cell death was noted, as was the lack of an injury-induced protective response in the rat models. EM analysis revealed the accumulation of submicron vesicular structures in the interphotoreceptor space during the peak period of PR outer segment degeneration in the S334ter lines. This is likely due to the elimination of the trafficking consensus domain as seen before as with other rhodopsin mutants lacking the C-terminal QVAPA. The 8 rhodopsin Tg lines have been, and will continue to be, extremely useful models for the experimental study of inherited retinal degenerations.
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Affiliation(s)
- Matthew M LaVail
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Shimpei Nishikawa
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Roy H Steinberg
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd., Room 2011, Houston, TX 77204-5060, USA.
| | - Jacque L Duncan
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Nikolaus Trautmann
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Michael T Matthes
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Douglas Yasumura
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA
| | - Cathy Lau-Villacorta
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Jeannie Chen
- Zilka Neurogenetic Institute, USC Keck School of Medicine, Los Angeles, CA 90089-2821, USA.
| | - Ward M Peterson
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - Haidong Yang
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143-0730, USA.
| | - John G Flannery
- School of Optometry, UC Berkeley, Berkeley, CA 94720-2020, USA.
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Burnight ER, Gupta M, Wiley LA, Anfinson KR, Tran A, Triboulet R, Hoffmann JM, Klaahsen DL, Andorf JL, Jiao C, Sohn EH, Adur MK, Ross JW, Mullins RF, Daley GQ, Schlaeger TM, Stone EM, Tucker BA. Using CRISPR-Cas9 to Generate Gene-Corrected Autologous iPSCs for the Treatment of Inherited Retinal Degeneration. Mol Ther 2017; 25:1999-2013. [PMID: 28619647 PMCID: PMC5589061 DOI: 10.1016/j.ymthe.2017.05.015] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 05/22/2017] [Accepted: 05/22/2017] [Indexed: 01/20/2023] Open
Abstract
Patient-derived induced pluripotent stem cells (iPSCs) hold great promise for autologous cell replacement. However, for many inherited diseases, treatment will likely require genetic repair pre-transplantation. Genome editing technologies are useful for this application. The purpose of this study was to develop CRISPR-Cas9-mediated genome editing strategies to target and correct the three most common types of disease-causing variants in patient-derived iPSCs: (1) exonic, (2) deep intronic, and (3) dominant gain of function. We developed a homology-directed repair strategy targeting a homozygous Alu insertion in exon 9 of male germ cell-associated kinase (MAK) and demonstrated restoration of the retinal transcript and protein in patient cells. We generated a CRISPR-Cas9-mediated non-homologous end joining (NHEJ) approach to excise a major contributor to Leber congenital amaurosis, the IVS26 cryptic-splice mutation in CEP290, and demonstrated correction of the transcript and protein in patient iPSCs. Lastly, we designed allele-specific CRISPR guides that selectively target the mutant Pro23His rhodopsin (RHO) allele, which, following delivery to both patient iPSCs in vitro and pig retina in vivo, created a frameshift and premature stop that would prevent transcription of the disease-causing variant. The strategies developed in this study will prove useful for correcting a wide range of genetic variants in genes that cause inherited retinal degeneration.
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Affiliation(s)
- Erin R Burnight
- Stephen A. Wynn Institute for Vision Research and Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52241, USA
| | - Manav Gupta
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 01451, USA
| | - Luke A Wiley
- Stephen A. Wynn Institute for Vision Research and Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52241, USA
| | - Kristin R Anfinson
- Stephen A. Wynn Institute for Vision Research and Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52241, USA
| | - Audrey Tran
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 01451, USA
| | - Robinson Triboulet
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 01451, USA
| | - Jeremy M Hoffmann
- Stephen A. Wynn Institute for Vision Research and Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52241, USA
| | - Darcey L Klaahsen
- Stephen A. Wynn Institute for Vision Research and Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52241, USA
| | - Jeaneen L Andorf
- Stephen A. Wynn Institute for Vision Research and Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52241, USA
| | - Chunhua Jiao
- Stephen A. Wynn Institute for Vision Research and Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52241, USA
| | - Elliott H Sohn
- Stephen A. Wynn Institute for Vision Research and Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52241, USA
| | - Malavika K Adur
- Department of Animal Sciences, Iowa State University, Ames, IA 50011, USA
| | - Jason W Ross
- Department of Animal Sciences, Iowa State University, Ames, IA 50011, USA
| | - Robert F Mullins
- Stephen A. Wynn Institute for Vision Research and Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52241, USA
| | - George Q Daley
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 01451, USA
| | - Thorsten M Schlaeger
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 01451, USA
| | - Edwin M Stone
- Stephen A. Wynn Institute for Vision Research and Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52241, USA
| | - Budd A Tucker
- Stephen A. Wynn Institute for Vision Research and Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52241, USA.
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Vecino E, Rodriguez FD, Ruzafa N, Pereiro X, Sharma SC. Glia-neuron interactions in the mammalian retina. Prog Retin Eye Res 2015; 51:1-40. [PMID: 26113209 DOI: 10.1016/j.preteyeres.2015.06.003] [Citation(s) in RCA: 493] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 05/18/2015] [Accepted: 06/02/2015] [Indexed: 02/07/2023]
Abstract
The mammalian retina provides an excellent opportunity to study glia-neuron interactions and the interactions of glia with blood vessels. Three main types of glial cells are found in the mammalian retina that serve to maintain retinal homeostasis: astrocytes, Müller cells and resident microglia. Müller cells, astrocytes and microglia not only provide structural support but they are also involved in metabolism, the phagocytosis of neuronal debris, the release of certain transmitters and trophic factors and K(+) uptake. Astrocytes are mostly located in the nerve fibre layer and they accompany the blood vessels in the inner nuclear layer. Indeed, like Müller cells, astrocytic processes cover the blood vessels forming the retinal blood barrier and they fulfil a significant role in ion homeostasis. Among other activities, microglia can be stimulated to fulfil a macrophage function, as well as to interact with other glial cells and neurons by secreting growth factors. This review summarizes the main functional relationships between retinal glial cells and neurons, presenting a general picture of the retina recently modified based on experimental observations. The preferential involvement of the distinct glia cells in terms of the activity in the retina is discussed, for example, while Müller cells may serve as progenitors of retinal neurons, astrocytes and microglia are responsible for synaptic pruning. Since different types of glia participate together in certain activities in the retina, it is imperative to explore the order of redundancy and to explore the heterogeneity among these cells. Recent studies revealed the association of glia cell heterogeneity with specific functions. Finally, the neuroprotective effects of glia on photoreceptors and ganglion cells under normal and adverse conditions will also be explored.
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Affiliation(s)
- Elena Vecino
- Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, Leioa 48940, Vizcaya, Spain
| | - F David Rodriguez
- Department of Biochemistry and Molecular Biology, E-37007, University of Salamanca, Salamanca, Spain
| | - Noelia Ruzafa
- Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, Leioa 48940, Vizcaya, Spain
| | - Xandra Pereiro
- Department of Cell Biology and Histology, University of the Basque Country UPV/EHU, Leioa 48940, Vizcaya, Spain
| | - Sansar C Sharma
- Department of Ophthalmology, Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595, USA; IKERBASQUE, Basque Foundation for Science at Dept. Cell Biology and Histology, UPV/EHU, Spain
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