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Miao Y, Zhao GL, Cheng S, Wang Z, Yang XL. Activation of retinal glial cells contributes to the degeneration of ganglion cells in experimental glaucoma. Prog Retin Eye Res 2023; 93:101169. [PMID: 36736070 DOI: 10.1016/j.preteyeres.2023.101169] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/12/2023] [Accepted: 01/24/2023] [Indexed: 02/04/2023]
Abstract
Elevation of intraocular pressure (IOP) is a major risk factor for neurodegeneration in glaucoma. Glial cells, which play an important role in normal functioning of retinal neurons, are well involved into retinal ganglion cell (RGC) degeneration in experimental glaucoma animal models generated by elevated IOP. In response to elevated IOP, mGluR I is first activated and Kir4.1 channels are subsequently inhibited, which leads to the activation of Müller cells. Müller cell activation is followed by a complex process, including proliferation, release of inflammatory and growth factors (gliosis). Gliosis is further regulated by several factors. Activated Müller cells contribute to RGC degeneration through generating glutamate receptor-mediated excitotoxicity, releasing cytotoxic factors and inducing microglia activation. Elevated IOP activates microglia, and following morphological and functional changes, these cells, as resident immune cells in the retina, show adaptive immune responses, including an enhanced release of pro-inflammatory factors (tumor neurosis factor-α, interleukins, etc.). These ATP and Toll-like receptor-mediated responses are further regulated by heat shock proteins, CD200R, chemokine receptors, and metabotropic purinergic receptors, may aggravate RGC loss. In the optic nerve head, astrogliosis is initiated and regulated by a complex reaction process, including purines, transmitters, chemokines, growth factors and cytokines, which contributes to RGC axon injury through releasing pro-inflammatory factors and changing extracellular matrix in glaucoma. The effects of activated glial cells on RGCs are further modified by the interplay among different types of glial cells. This review is concluded by presenting an in-depth discussion of possible research directions in this field in the future.
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Affiliation(s)
- Yanying Miao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Guo-Li Zhao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Shuo Cheng
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Zhongfeng Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
| | - Xiong-Li Yang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
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2
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Bonilla-Pons SÀ, Nakagawa S, Bahima EG, Fernández-Blanco Á, Pesaresi M, D'Antin JC, Sebastian-Perez R, Greco D, Domínguez-Sala E, Gómez-Riera R, Compte RIB, Dierssen M, Pulido NM, Cosma MP. Müller glia fused with adult stem cells undergo neural differentiation in human retinal models. EBioMedicine 2022; 77:103914. [PMID: 35278743 PMCID: PMC8917309 DOI: 10.1016/j.ebiom.2022.103914] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/09/2022] [Accepted: 02/18/2022] [Indexed: 12/15/2022] Open
Abstract
Background Visual impairments are a critical medical hurdle to be addressed in modern society. Müller glia (MG) have regenerative potential in the retina in lower vertebrates, but not in mammals. However, in mice, in vivo cell fusion between MG and adult stem cells forms hybrids that can partially regenerate ablated neurons. Methods We used organotypic cultures of human retina and preparations of dissociated cells to test the hypothesis that cell fusion between human MG and adult stem cells can induce neuronal regeneration in human systems. Moreover, we established a microinjection system for transplanting human retinal organoids to demonstrate hybrid differentiation. Findings We first found that cell fusion occurs between MG and adult stem cells, in organotypic cultures of human retina as well as in cell cultures. Next, we showed that the resulting hybrids can differentiate and acquire a proto-neural electrophysiology profile when the Wnt/beta-catenin pathway is activated in the adult stem cells prior fusion. Finally, we demonstrated the engraftment and differentiation of these hybrids into human retinal organoids. Interpretation We show fusion between human MG and adult stem cells, and demonstrate that the resulting hybrid cells can differentiate towards neural fate in human model systems. Our results suggest that cell fusion-mediated therapy is a potential regenerative approach for treating human retinal dystrophies. Funding This work was supported by La Caixa Health (HR17-00231), Velux Stiftung (976a) and the Ministerio de Ciencia e Innovación, (BFU2017-86760-P) (AEI/FEDER, UE), AGAUR (2017 SGR 689, 2017 SGR 926).
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Affiliation(s)
- Sergi Àngel Bonilla-Pons
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, C/Dr. Aiguader 88, Barcelona 08003, Spain; Universitat de Barcelona (UB), Barcelona, Spain
| | - Shoma Nakagawa
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, C/Dr. Aiguader 88, Barcelona 08003, Spain
| | - Elena Garreta Bahima
- Pluripotency for Organ Regeneration, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Álvaro Fernández-Blanco
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, C/Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Martina Pesaresi
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, C/Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Justin Christopher D'Antin
- Centro de Oftalmología Barraquer, Barcelona, Spain; Institut Universitari Barraquer, Universitat Autónoma de Barcelona, Barcelona, Spain
| | - Ruben Sebastian-Perez
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, C/Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Daniela Greco
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, C/Dr. Aiguader 88, Barcelona 08003, Spain
| | - Eduardo Domínguez-Sala
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, C/Dr. Aiguader 88, Barcelona 08003, Spain
| | - Raúl Gómez-Riera
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, C/Dr. Aiguader 88, Barcelona 08003, Spain
| | - Rafael Ignacio Barraquer Compte
- Centro de Oftalmología Barraquer, Barcelona, Spain; Institut Universitari Barraquer, Universitat Autónoma de Barcelona, Barcelona, Spain
| | - Mara Dierssen
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, C/Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; Biomedical Research Networking Centre On Rare Diseases (CIBERER), Institute of Health Carlos III, Madrid, Spain
| | - Nuria Montserrat Pulido
- Pluripotency for Organ Regeneration, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain; ICREA, Pg. Lluis Companys 23, Barcelona 08010, Spain
| | - Maria Pia Cosma
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, C/Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; ICREA, Pg. Lluis Companys 23, Barcelona 08010, Spain; Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, China; CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell an Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Science, Guangzhou 510530, China.
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3
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Lin TC, Wang LC, Yue L, Zhang Y, Falabella P, Zhu D, Hinton DR, Rao NA, Birch DG, Spencer R, Dorn JD, Humayun MS. Histopathologic Assessment of Optic Nerves and Retina From a Patient With Chronically Implanted Argus II Retinal Prosthesis System. Transl Vis Sci Technol 2019; 8:31. [PMID: 31171998 PMCID: PMC6543856 DOI: 10.1167/tvst.8.3.31] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 04/01/2019] [Indexed: 01/20/2023] Open
Abstract
Purpose To characterize histologic changes in the optic nerve and the retina of an end-stage retinitis pigmentosa (RP) patient after long-term implantation with the Argus II retinal prosthesis system. Methods Serial cross sections from the patient's both eyes were collected postmortem 6 years after implantation. Optic nerve from both eyes were morphometrically analyzed and compared. Retina underneath and outside the array was analyzed and compared with corresponding regions in the fellow eye. Results Although the optic nerve of the implant eye demonstrated significantly more overall atrophy than the fellow eye (P < 0.01), the temporal quadrant that retinotopically corresponded to the location of the array did not show additional damage. The total neuron count of the macular area was not significantly different between the two eyes, but the tack locations and their adjacent areas showed significantly fewer neurons than other perimacular areas. There was an increased expression of glial fibrillary acidic protein (GFAP) throughout the retina in the implant eye versus the fellow eye, but there was no significant difference in the cellular retinaldehyde-binding protein (CRALBP) expression. Except for the revision tack site, no significant increase of inflammatory reaction was detected in the implant eye. Conclusion Long-term implantation and electrical stimulation with an Argus II retinal prosthesis system did not result in significant tissue damage that could be detected by a morphometric analysis. Translational Relevance This study supports the long-term safety of the Argus II device and encourages further development of bioelectronics devices at the retina-machine interface.
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Affiliation(s)
- Tai-Chi Lin
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA.,USC Ginsburg Institute for Biomedical Therapeutics, University of Southern California, Los Angeles, CA, USA.,Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan, Republic of China.,Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Lei-Chi Wang
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA.,Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, Republic of China.,School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Lan Yue
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA.,USC Ginsburg Institute for Biomedical Therapeutics, University of Southern California, Los Angeles, CA, USA
| | - Yi Zhang
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Paulo Falabella
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA.,Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, São Paulo, Brazil
| | - Danhong Zhu
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA.,Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - David R Hinton
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA.,Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Narsing A Rao
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA.,Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | | | | | - Jessy D Dorn
- Second Sight Medical Products, Inc., Sylmar, CA, USA
| | - Mark S Humayun
- Department of Ophthalmology, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA.,USC Ginsburg Institute for Biomedical Therapeutics, University of Southern California, Los Angeles, CA, USA
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4
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Wu HJ, Li XY, Qian WJ, Li Q, Wang SY, Ji M, Ma YY, Gao F, Sun XH, Wang X, Miao Y, Yang XL, Wang Z. Dopamine D1 receptor-mediated upregulation of BKCa
currents modifies Müller cell gliosis in a rat chronic ocular hypertension model. Glia 2018; 66:1507-1519. [PMID: 29508439 DOI: 10.1002/glia.23321] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 02/15/2018] [Accepted: 02/19/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Hang-Jing Wu
- Department of Neurology; Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University; Shanghai 200032 China
| | - Xue-Yan Li
- Department of Neurology; Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University; Shanghai 200032 China
| | - Wen-Jing Qian
- Department of Neurology; Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University; Shanghai 200032 China
| | - Qian Li
- Department of Neurology; Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University; Shanghai 200032 China
| | - Shu-Yue Wang
- Department of Neurology; Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University; Shanghai 200032 China
| | - Min Ji
- Department of Ophthalmology at Eye & ENT Hospital; Fudan University; Shanghai 200031 China
| | - Yuan-Yuan Ma
- Department of Neurology; Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University; Shanghai 200032 China
| | - Feng Gao
- Department of Ophthalmology at Eye & ENT Hospital; Fudan University; Shanghai 200031 China
| | - Xing-Huai Sun
- Department of Ophthalmology at Eye & ENT Hospital; Fudan University; Shanghai 200031 China
| | - Xin Wang
- Department of Neurology; Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University; Shanghai 200032 China
| | - Yanying Miao
- Department of Neurology; Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University; Shanghai 200032 China
| | - Xiong-Li Yang
- Department of Neurology; Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University; Shanghai 200032 China
| | - Zhongfeng Wang
- Department of Neurology; Institutes of Brain Science, State Key Laboratory of Medical Neurobiology, Zhongshan Hospital, Fudan University; Shanghai 200032 China
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Abstract
Müller glia, the principal macroglia of the retina, express diverse subtypes of adenosine and metabotropic purinergic (P2Y) receptors. Müller cells of several species, including man, also express ionotropic P2X7 receptors. ATP is liberated from Müller cells after activation of metabotropic glutamate receptors and during osmotic and mechanical induction of membrane stretch; adenosine is released through equilibrative nucleoside transporters. Müller cell-derived purines modulate the neuronal activity and have autocrine effects, for example, induction of glial calcium waves and regulation of the cellular volume. Glial calcium waves induced by neuron-derived ATP mediate functional hyperemia in the retina. Purinergic signaling contributes to the induction of Müller cell gliosis, for example, of cellular proliferation and downregulation of potassium channels, which are important for the homeostatic functions of Müller cells. Purinergic glial calcium waves may also promote the long-range propagation of gliosis and neuronal degeneration across the retinal tissue. The osmotic ATP release is inhibited under pathological conditions. Inhibition of the ATP release may result in osmotic Müller cell swelling and dysregulation of the water transport through the cells; both may contribute to the development of retinal edema. Suppression of the osmotic ATP release and upregulation of the ecto-apyrase (NTPDase1), which facilitate the extracellular degradation of ATP and the formation of adenosine, may protect neurons and photoreceptors from death due to overactivation of P2X receptors. Pharmacological inhibition of P2X7 receptors and stimulation of adenosine receptors may represent clinical approaches to prevent retinal cell death and dysregulated cell proliferation, and to treat retinal edema.
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Affiliation(s)
- Andreas Reichenbach
- 1 Paul Flechsig Institute of Brain Research, University of Leipzig , Leipzig, Germany
| | - Andreas Bringmann
- 2 Department of Ophthalmology and Eye Hospital, University of Leipzig , Leipzig, Germany
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6
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Pannicke T, Ivo Chao T, Reisenhofer M, Francke M, Reichenbach A. Comparative electrophysiology of retinal Müller glial cells-A survey on vertebrate species. Glia 2016; 65:533-568. [PMID: 27767232 DOI: 10.1002/glia.23082] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/15/2016] [Accepted: 09/28/2016] [Indexed: 12/13/2022]
Abstract
Müller cells are the dominant macroglial cells in the retina of all vertebrates. They fulfill a variety of functions important for retinal physiology, among them spatial buffering of K+ ions and uptake of glutamate and other neurotransmitters. To this end, Müller cells express inwardly rectifying K+ channels and electrogenic glutamate transporters. Moreover, a lot of voltage- and ligand-gated ion channels, aquaporin water channels, and electrogenic transporters are expressed in Müller cells, some of them in a species-specific manner. For example, voltage-dependent Na+ channels are found exclusively in some but not all mammalian species. Whereas a lot of data exist from amphibians and mammals, the results from other vertebrates are sparse. It is the aim of this review to present a survey on Müller cell electrophysiology covering all classes of vertebrates. The focus is on functional studies, mainly performed using the whole-cell patch-clamp technique. However, data about the expression of membrane channels and transporters from immunohistochemistry are also included. Possible functional roles of membrane channels and transporters are discussed. Obviously, electrophysiological properties involved in the main functions of Müller cells developed early in vertebrate evolution. GLIA 2017;65:533-568.
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Affiliation(s)
- Thomas Pannicke
- Paul-Flechsig-Institut für Hirnforschung, Abteilung Pathophysiologie der Neuroglia, Universität Leipzig, Germany
| | - T Ivo Chao
- Institute of Anatomy and Cell Biology, Medical School Göttingen, Germany
| | - Miriam Reisenhofer
- Department of Chemistry, University of Zürich, Switzerland
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Mike Francke
- Paul-Flechsig-Institut für Hirnforschung, Abteilung Pathophysiologie der Neuroglia, Universität Leipzig, Germany
- Sächsischer Inkubator für klinische Translation (SIKT), Universität Leipzig, Germany
| | - Andreas Reichenbach
- Paul-Flechsig-Institut für Hirnforschung, Abteilung Pathophysiologie der Neuroglia, Universität Leipzig, Germany
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7
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Lassiale S, Valamanesh F, Klein C, Hicks D, Abitbol M, Versaux-Botteri C. Changes in aquaporin-4 and Kir4.1 expression in rats with inherited retinal dystrophy. Exp Eye Res 2016; 148:33-44. [DOI: 10.1016/j.exer.2016.05.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Revised: 05/04/2016] [Accepted: 05/09/2016] [Indexed: 10/21/2022]
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8
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Vogler S, Pannicke T, Hollborn M, Kolibabka M, Wiedemann P, Reichenbach A, Hammes HP, Bringmann A. Impaired Purinergic Regulation of the Glial (Müller) Cell Volume in the Retina of Transgenic Rats Expressing Defective Polycystin-2. Neurochem Res 2016; 41:1784-96. [PMID: 27038933 DOI: 10.1007/s11064-016-1894-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 03/16/2016] [Accepted: 03/17/2016] [Indexed: 12/19/2022]
Abstract
Retinal glial (Müller) cells possess an endogenous purinergic signal transduction cascade which normally prevents cellular swelling in osmotic stress. The cascade can be activated by osmotic or glutamate receptor-dependent ATP release. We determined whether activation of this cascade is altered in Müller cells of transgenic rats that suffer from a slow photoreceptor degeneration due to the expression of a truncated human cilia gene polycystin-2 (CMV-PKD21/703 HA). Age-matched Sprague-Dawley rats served as control. Retinal slices were superfused with a hypoosmotic solution (60 % osmolarity). Müller cells in retinas of PKD21/703 rats swelled immediately in hypoosmotic stress; this was not observed in control retinas. Pharmacological blockade of P2Y1 or adenosine A1 receptors induced osmotic swelling of Müller cells from control rats. The swelling induced by the P2Y1 receptor antagonist was mediated by induction of oxidative-nitrosative stress, mitochondrial dysfunction, production of inflammatory lipid mediators, and a sodium influx from the extracellular space. Exogenous VEGF or glutamate prevented the hypoosmotic swelling of Müller cells from PKD21/703 rats; this effect was mediated by activation of the purinergic signaling cascade. In neuroretinas of PKD21/703 rats, the gene expression levels of P2Y1 and A1 receptors, pannexin-1, connexin 45, NTPDases 1 and 2, and various subtypes of nucleoside transporters are elevated compared to control. The data may suggest that the osmotic swelling of Müller cells from PKD21/703 rats is caused by an abrogation of the osmotic ATP release while the glutamate-induced ATP release is functional. In the normal retina, ATP release and autocrine P2Y1 receptor activation serve to inhibit the induction of oxidative-nitrosative stress, mitochondrial dysfunction, and production of inflammatory lipid mediators, which otherwise will induce a sodium influx and cytotoxic Müller cell swelling under anisoosmotic conditions. Purinergic receptors may represent a target for the protection of retinal glial cells from mitochondrial oxidative stress.
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Affiliation(s)
- Stefanie Vogler
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
| | - Thomas Pannicke
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
| | - Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Liebigstrasse 10-14, 04103, Leipzig, Germany
| | - Matthias Kolibabka
- 5th Medical Department, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Liebigstrasse 10-14, 04103, Leipzig, Germany
| | - Andreas Reichenbach
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
| | - Hans-Peter Hammes
- 5th Medical Department, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Liebigstrasse 10-14, 04103, Leipzig, Germany.
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10
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Voigt J, Grosche A, Vogler S, Pannicke T, Hollborn M, Kohen L, Wiedemann P, Reichenbach A, Bringmann A. Nonvesicular release of ATP from rat retinal glial (Müller) cells is differentially mediated in response to osmotic stress and glutamate. Neurochem Res 2015; 40:651-60. [PMID: 25567481 DOI: 10.1007/s11064-014-1511-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 12/29/2014] [Indexed: 01/01/2023]
Abstract
Retinal glial (Müller) cells release ATP upon osmotic stress or activation of metabotropic glutamate receptors. ATP inhibits the osmotic Müller cell swelling by activation of P2Y1 receptors. In the present study, we determined the molecular pathways of the ATP release from Müller cells in slices of the rat retina. Administration of the ATP/ADPase apyrase induced a swelling of Müller cells under hypoosmotic conditions, and prevented the swelling-inhibitory effect of glutamate, suggesting that swelling inhibition is mediated by extracellular ATP. A hypoosmotic swelling of Müller cells was also observed in the presence of a blocker of multidrug resistance channels (MK-571), a CFTR inhibitor (glibenclamide), and connexin hemichannel blockers (18-α-glycyrrhetinic acid, 100 µM carbenoxolone). The swelling-inhibitory effect of glutamate was prevented by MK-571, the connexin hemichannel blockers, and a pannexin-1 hemichannel blocker (5 µM carbenoxolone). The p-glycoprotein blocker verapamil had no effect. As revealed by single-cell RT-PCR, subpopulations of Müller cells expressed mRNAs for pannexin-1 and -2, and connexins 30, 30.3, 32, 43, 45, and 46. The data may suggest that rat Müller cells release ATP by multidrug resistance channels, CFTR, and connexin hemichannels in response to osmotic stress, while glutamate induces a release of ATP via multidrug resistance channels, connexin hemichannels, and pannexin-1.
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Affiliation(s)
- Juliane Voigt
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
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11
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Métrailler S, Emery M, Schorderet DF, Cottet S, Roduit R. ERK1/2 pathway is activated in degenerated Rpe65-deficient mice. Exp Eye Res 2013; 116:86-95. [PMID: 24012986 DOI: 10.1016/j.exer.2013.08.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 08/10/2013] [Accepted: 08/22/2013] [Indexed: 12/30/2022]
Abstract
The MAPK family is composed of three majors kinases, JNK, p38 and ERK1/2, and is implicated in many degenerative processes, including retinal cell death. The purpose of our study was to evaluate the activation of ERK1/2 kinase, and its potential role in Müller cell gliosis, during photoreceptor cell death in Rpe65(-/-) mice. We assayed ERK1/2 mRNA and protein levels, and evaluated ERK1/2 phosphorylation involved in kinase activation, in 2, 4 and 6 month-old Rpe65(-/-) mice and in age-matched wild-type controls. No differences in ERK1/2 expression were detected between Rpe65(-/-) and wild-type mice, however, ERK1/2 phosphorylation was dramatically increased in the knock out mice at 4 and 6 months-of-age. Phosphorylated ERK1/2 co-localized with GFAP in the ganglion cell layer, and correlated with an increase in GFAP protein expression and retinal cell death. Accumulation of cFOS protein in the ganglion cell layer occurred concomitant with pERK1/2 activation. Müller cell proliferation was not observed. ERK1/2 activation did not occur in 2 month-old Rpe65(-/-) or in the Rpe65(-/-)/Gnat1(-/-) mice, in which no degeneration was evident. The observed activation ERK1/2 and GFAP, both markers of Müller cell gliosis, in the absence of Müller cell proliferation, is consistent with the activation of atypical gliosis occurring during the slow process of degeneration in Rpe65(-/-) mice. As Müller cell gliosis is activated in many neuronal and retinal degenerative diseases, further studies will be needed to determine whether atypical gliosis in Rpe65(-/-) mice contributes to, or protects against, the pathogenesis occurring in this model of Leber congenital amaurosis.
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Affiliation(s)
- S Métrailler
- IRO, Institute for Research in Ophthalmology, 1950 Sion, Switzerland
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12
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Chen Z, Song Y, Yao J, Weng C, Yin ZQ. Alterations of sodium and potassium channels of RGCs in RCS rat with the development of retinal degeneration. J Mol Neurosci 2013; 51:976-85. [PMID: 23934450 DOI: 10.1007/s12031-013-0082-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 07/22/2013] [Indexed: 11/28/2022]
Abstract
All know that retinitis pigmentosa (RP) is a group of hereditary retinal degenerative diseases characterized by progressive dysfunction of photoreceptors and associated with progressive cells loss; nevertheless, little is known about how rods and cones loss affects the surviving inner retinal neurons and networks. Retinal ganglion cells (RGCs) process and convey visual information from retina to visual centers in the brain. The healthy various ion channels determine the normal reception and projection of visual signals from RGCs. Previous work on the Royal College of Surgeons (RCS) rat, as a kind of classical RP animal model, indicated that, at late stages of retinal degeneration in RCS rat, RGCs were also morphologically and functionally affected. Here, retrograde labeling for RGCs with Fluorogold was performed to investigate the distribution, density, and morphological changes of RGCs during retinal degeneration. Then, patch clamp recording, western blot, and immunofluorescence staining were performed to study the channels of sodium and potassium properties of RGCs, so as to explore the molecular and proteinic basis for understanding the alterations of RGCs membrane properties and firing functions. We found that the resting membrane potential, input resistance, and capacitance of RGCs changed significantly at the late stage of retinal degeneration. Action potential could not be evoked in a part of RGCs. Inward sodium current and outward potassium current recording showed that sodium current was impaired severely but only slightly in potassium current. Expressions of sodium channel protein were impaired dramatically at the late stage of retinal degeneration. The results suggested that the density of RGCs decreased, process ramification impaired, and sodium ion channel proteins destructed, which led to the impairment of electrophysiological functions of RGCs and eventually resulted in the loss of visual function.
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Affiliation(s)
- Zhongshan Chen
- Southwest Hospital, Southwest Eye Hospital, Third Military Medical University, Chongqing, 400038, China
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Park S, Lee YJ. Nano-mechanical compliance of Müller cells investigated by atomic force microscopy. Int J Biol Sci 2013; 9:702-6. [PMID: 23904794 PMCID: PMC3729012 DOI: 10.7150/ijbs.6473] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 07/11/2013] [Indexed: 01/02/2023] Open
Abstract
It has been known that a single Müller cell displays a large variation in the cytoskeletal compositions along its cell body, suggesting different mechanical properties in different segments. Müller cells are thought to be involved in many retinal diseases such as retinoschisis, which can be facilitated by a mechanical stress. Thus, mapping of mechanical properties on localized nano-domains of Müller cells could provide essential information for understanding their structural functions in the retina and roles in their pathological progresses. Using Atomic Force Microscopy (AFM) - based bio-nano-mechanics, we have investigated the local variations of the mechanical properties of Müller cells in vitro. We have a particular interest in identifying elastic moduli in regions closer to three distinctive segments of the cells - process, endfoot, and soma. Using the modified spherical AFM probes, we were able to accurately determine mechanical properties, i.e., elastic moduli from the obtained force-distance curves. We found that the regions closer to soma were mechanically more compliant than regions closer to endfoot and process of Müller cells. We found that this lateral heterogeneity of the mechanical compliance within a single Müller cell is consistent with reports from other cell types. The local variation in mechanical compliances along a single Müller cell may support their diverse mechanical functions in the retina such as a soft mechanical embedding, mechanosensing, and neurotrophic functions for neurons.
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Affiliation(s)
- Soyeun Park
- Department of Physics, Texas Tech University, Box 41051, Lubbock, TX 79409, USA.
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Chua J, Nivison-Smith L, Fletcher EL, Trenholm S, Awatramani GB, Kalloniatis M. Early remodeling of müller cells in therd/rdmouse model of retinal dystrophy. J Comp Neurol 2013; 521:2439-53. [DOI: 10.1002/cne.23307] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Revised: 12/11/2012] [Accepted: 01/17/2013] [Indexed: 12/13/2022]
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15
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Vogler S, Pannicke T, Hollborn M, Grosche A, Busch S, Hoffmann S, Wiedemann P, Reichenbach A, Hammes HP, Bringmann A. Müller cell reactivity in response to photoreceptor degeneration in rats with defective polycystin-2. PLoS One 2013; 8:e61631. [PMID: 23755094 PMCID: PMC3670868 DOI: 10.1371/journal.pone.0061631] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 03/12/2013] [Indexed: 12/18/2022] Open
Abstract
Background Retinal degeneration in transgenic rats that express a mutant cilia gene polycystin-2 (CMV-PKD2(1/703)HA) is characterized by initial photoreceptor degeneration and glial activation, followed by vasoregression and neuronal degeneration (Feng et al., 2009, PLoS One 4: e7328). It is unknown whether glial activation contributes to neurovascular degeneration after photoreceptor degeneration. We characterized the reactivity of Müller glial cells in retinas of rats that express defective polycystin-2. Methods Age-matched Sprague-Dawley rats served as control. Retinal slices were immunostained for intermediate filaments, the potassium channel Kir4.1, and aquaporins 1 and 4. The potassium conductance of isolated Müller cells was recorded by whole-cell patch clamping. The osmotic swelling characteristics of Müller cells were determined by superfusion of retinal slices with a hypoosmotic solution. Findings Müller cells in retinas of transgenic rats displayed upregulation of GFAP and nestin which was not observed in control cells. Whereas aquaporin-1 labeling of photoreceptor cells disappeared along with the degeneration of the cells, aquaporin-1 emerged in glial cells in the inner retina of transgenic rats. Aquaporin-4 was upregulated around degenerating photoreceptor cells. There was an age-dependent redistribution of Kir4.1 in retinas of transgenic rats, with a more even distribution along glial membranes and a downregulation of perivascular Kir4.1. Müller cells of transgenic rats displayed a slight decrease in their Kir conductance as compared to control. Müller cells in retinal tissues from transgenic rats swelled immediately under hypoosmotic stress; this was not observed in control cells. Osmotic swelling was induced by oxidative-nitrosative stress, mitochondrial dysfunction, and inflammatory lipid mediators. Interpretation Cellular swelling suggests that the rapid water transport through Müller cells in response to osmotic stress is altered as compared to control. The dislocation of Kir4.1 will disturb the retinal potassium and water homeostasis, and osmotic generation of free radicals and inflammatory lipids may contribute to neurovascular injury.
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Affiliation(s)
- Stefanie Vogler
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
| | - Thomas Pannicke
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
| | - Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Antje Grosche
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
| | - Stephanie Busch
- 5th Medical Department, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Sigrid Hoffmann
- Medical Research Center, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Andreas Reichenbach
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
| | - Hans-Peter Hammes
- 5th Medical Department, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
- * E-mail:
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Zhao T, Li Y, Weng C, Yin Z. The changes of potassium currents in RCS rat Müller cell during retinal degeneration. Brain Res 2011; 1427:78-87. [PMID: 22055109 DOI: 10.1016/j.brainres.2011.10.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Revised: 09/12/2011] [Accepted: 10/05/2011] [Indexed: 11/19/2022]
Abstract
Müller cells are the principal glial cells expressing membrane-bound potassium channel and predominantly mediating the homeostatic regulation of extracellular K+ produced by neuronal activity in retina. It's well known that Müller cells can be activated in many pathological conditions, but little is known about the change of potassium currents of Müller cells during the progression of retinitis pigmentosa. Herein, the Royal College of Surgeons rats (RCS rat) were employed to investigate some phenotypic and functional changes of Müller cells during retinal degeneration such as the expression of Kir4.1, membrane properties and K+ channel currents by using immunohistochemistry, RT-PCR, western blot and whole-cell patch clamping respectively. Compared with Müller cells in control retina, increased glutamine synthetase (GS) mRNA levels were seen at P30 and P60, and then decreased gradually in RCS rat retina. Morphologically, Müller cells showed significant hypertrophy and proliferation after p60. The increased expression of intermediate filament, glial fibrillary acidic protein (GFAP) and vimentin began at P30 and reached a peak at p60. Kir4.1 channels presented a peak expression at P30. Concomitantly, K(+) currents of Müller cells increased at P30 and decreased at P90 significantly. We concluded that retinal Müller cells of RCS rats underwent an activation initiated by the onset of retinal degeneration before p60 and then an obvious reactive gliosis, which led the basic membrane properties to suffer marked changes, and caused the Kir4.1 channels of Müller cells to occur a clear functional shift, even lose their normal electrophysiological properties. This process aggravates the impairment caused by the initial photoreceptor degeneration.
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Affiliation(s)
- TongTao Zhao
- Southwest Hospital, Southwest Eye Hospital, Third Military Medical University, Chongqing 400038, China
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Brückner E, Grosche A, Pannicke T, Wiedemann P, Reichenbach A, Bringmann A. Mechanisms of VEGF- and glutamate-induced inhibition of osmotic swelling of murine retinal glial (Müller) cells: indications for the involvement of vesicular glutamate release and connexin-mediated ATP release. Neurochem Res 2011; 37:268-78. [PMID: 21938552 DOI: 10.1007/s11064-011-0606-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 09/08/2011] [Accepted: 09/10/2011] [Indexed: 11/24/2022]
Abstract
We determined the mechanisms of glutamate and ATP release from murine retinal glial (Müller) cells by pharmacological manipulation of the vascular endothelial growth factor (VEGF)- and glutamate-induced inhibition of cellular swelling under hypoosmotic conditions. It has been shown that exogenous glutamate inhibits hypoosmotic swelling of rat Müller cells via the induction of the release of ATP (Uckermann et al. in J Neurosci Res 83:538-550, 53). VEGF was shown to inhibit hypoosmotic swelling of rat Müller cells by inducing the release of glutamate (Wurm et al. in J Neurochem 104:386-399, 55). The swelling-inhibitory effect of VEGF in murine Müller cells was blocked by an inhibitor of vesicular exocytosis, by a modulator of the allosteric site of vesicular glutamate transporters, and by inhibitors of phospholipase C and protein kinase C. The swelling-inhibitory effect of glutamate in murine Müller cells was prevented by inhibitors of connexin hemichannels. The effects of both VEGF and glutamate were blocked by tetrodotoxin and by an inhibitor of T-type voltage-gated calcium channels. Murine Müller cells display connexin-43 immunoreactivity. The data suggest that Müller cells of the murine retina may release glutamate by vesicular exocytosis, whereas ATP is released through connexin hemichannels.
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Affiliation(s)
- Erik Brückner
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
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18
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Wurm A, Pannicke T, Iandiev I, Francke M, Hollborn M, Wiedemann P, Reichenbach A, Osborne NN, Bringmann A. Purinergic signaling involved in Müller cell function in the mammalian retina. Prog Retin Eye Res 2011; 30:324-42. [DOI: 10.1016/j.preteyeres.2011.06.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 06/06/2011] [Accepted: 06/06/2011] [Indexed: 10/18/2022]
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Wurm A, Erdmann I, Bringmann A, Reichenbach A, Pannicke T. Expression and function of P2Y receptors on Müller cells of the postnatal rat retina. Glia 2009; 57:1680-90. [PMID: 19373936 DOI: 10.1002/glia.20883] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In the postnatal and mature retina, many processes are controlled by the action of nucleotides. Their effects are partly mediated via activation of metabotropic P2Y receptors. However, little is known about the developmental regulation and cellular localization of P2Y receptor subtypes. Combining immunohistochemical and neurophysiological methods, we investigated the developmental expression of P2Y receptors on Müller cells, the principal macroglial cells of the retina. The P2Y(1) and the P2Y(4) receptors, but no other subtypes, were unequivocally localized on Müller cells. P2Y(1) was expressed from postnatal day 5 (P5) on and mediated a calcium response to ATP in Müller cells as well as a volume regulatory signaling cascade preventing Müller cells from swelling under hypotonic conditions. Differentiation of Müller cells was accompanied by a change of the calcium response pattern; the calcium responses in Müller cell endfeet persisted, but ATP responsiveness of Müller cell somata disappeared. P2Y(4) immunoreactivity was observed in Müller cell endfeet and synaptic terminals of rod bipolar cells from P20 on. Activated protein kinases were detected by immunohistochemistry; p-ERK occurred in Müller cells and amacrine cells, whereas p-Akt was detected in bipolar cells. Our data indicate that purinergic signaling via P2Y(1) and P2Y(4) receptors might contribute to differentiation processes in the postnatal retina.
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Affiliation(s)
- Antje Wurm
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany.
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20
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Bringmann A, Iandiev I, Pannicke T, Wurm A, Hollborn M, Wiedemann P, Osborne NN, Reichenbach A. Cellular signaling and factors involved in Müller cell gliosis: neuroprotective and detrimental effects. Prog Retin Eye Res 2009; 28:423-51. [PMID: 19660572 DOI: 10.1016/j.preteyeres.2009.07.001] [Citation(s) in RCA: 515] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Müller cells are active players in normal retinal function and in virtually all forms of retinal injury and disease. Reactive Müller cells protect the tissue from further damage and preserve tissue function by the release of antioxidants and neurotrophic factors, and may contribute to retinal regeneration by the generation of neural progenitor/stem cells. However, Müller cell gliosis can also contribute to neurodegeneration and impedes regenerative processes in the retinal tissue by the formation of glial scars. This article provides an overview of the neuroprotective and detrimental effects of Müller cell gliosis, with accounts on the cellular signal transduction mechanisms and factors which are implicated in Müller cell-mediated neuroprotection, immunomodulation, regulation of Müller cell proliferation, upregulation of intermediate filaments, glial scar formation, and the generation of neural progenitor/stem cells. A proper understanding of the signaling mechanisms implicated in gliotic alterations of Müller cells is essential for the development of efficient therapeutic strategies that increase the supportive/protective and decrease the destructive roles of gliosis.
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Affiliation(s)
- Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Liebigstrasse 10-14, D-04103 Leipzig, Germany.
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21
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Iandiev I, Wurm A, Pannicke T, Wiedemann P, Reichenbach A, Robson SC, Zimmermann H, Bringmann A. Ectonucleotidases in Müller glial cells of the rodent retina: Involvement in inhibition of osmotic cell swelling. Purinergic Signal 2007; 3:423-33. [PMID: 18404455 PMCID: PMC2072913 DOI: 10.1007/s11302-007-9061-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Accepted: 07/10/2007] [Indexed: 11/20/2022] Open
Abstract
Extracellular nucleotides mediate glia-to-neuron signalling in the retina and are implicated in the volume regulation of retinal glial (Müller) cells under osmotic stress conditions. We investigated the expression and functional role of ectonucleotidases in Müller cells of the rodent retina by cell-swelling experiments, calcium imaging, and immuno- and enzyme histochemistry. The swelling of Müller cells under hypoosmotic stress was inhibited by activation of an autocrine purinergic signalling cascade. This cascade is initiated by exogenous glutamate and involves the consecutive activation of P2Y1 and adenosine A1 receptors, the action of ectoadenosine 5′-triphosphate (ATP)ases, and a nucleoside-transporter-mediated release of adenosine. Inhibition of ectoapyrases increased the ATP-evoked calcium responses in Müller cell endfeet. Müller cells were immunoreactive for nucleoside triphosphate diphosphohydrolases (NTPDase)2 (but not NTPDase1), ecto-5′-nucleotidase, P2Y1, and A1 receptors. Enzyme histochemistry revealed that ATP but not adenosine 5′-diphosphate (ADP) is extracellularly metabolised in retinal slices of NTPDase1 knockout mice. NTPDase1 activity and protein is restricted to blood vessels, whereas activity of alkaline phosphatase is essentially absent at physiological pH. The data suggest that NTPDase2 is the major ATP-degrading ectonucleotidase of the retinal parenchyma. NTPDase2 expressed by Müller cells can be implicated in the regulation of purinergic calcium responses and cellular volume.
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Affiliation(s)
- Ianors Iandiev
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
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22
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Iandiev I, Biedermann B, Bringmann A, Reichel MB, Reichenbach A, Pannicke T. Atypical gliosis in Müller cells of the slowly degenerating rds mutant mouse retina. Exp Eye Res 2006; 82:449-57. [PMID: 16154566 DOI: 10.1016/j.exer.2005.07.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2005] [Revised: 04/26/2005] [Accepted: 07/31/2005] [Indexed: 10/25/2022]
Abstract
Retinal Müller glial cells are known to undergo reactive changes (gliosis) in various retinal diseases. In virtually all cases studied, an upregulation of glial fibrillary acidic protein (GFAP) and a hypertrophy can be observed. Physiological alterations, such as a strong downregulation of inwardly rectifying K+ (Kir) currents, were found after retinal detachment (man, rabbit) and after ischemia/reperfusion (rat) but not in more slowly progressing retinal degenerations (Borna Disease Virus-infected rats, RCS rats). This led us to hypothesize that Müller cells respond with 'typical' reactive gliosis only to rapid but not to slow retinal degeneration. To test this hypothesis, we studied Müller cells from rds mutant mice (PrphRd2), which show a retinal degeneration of early onset and slow progression, resulting in a complete loss of photoreceptors after 9-12 months. In Müller cells of rds mice, we found immunoreactivity for GFAP, a marker of gliosis in Müller cells, from postnatal day 21 on, accompanied by a moderately increased membrane capacitance (taken as an indicator of hypertrophy), whereas no change in the expression of the Kir4.1 protein occurred in adult rds mice. We failed to observe significant changes in the membrane resistance and the membrane potential of cells from rds mice from first week after birth until 1 year of age. Current densities were decreased in cells from 3- and 5-week old rds mice. Furthermore, as in control cells from wildtype animals, these cells displayed dominant Kir currents, voltage-dependent Na+ currents, and glutamate uptake currents. These data support the idea that in mice as well as previously shown in rats, slow retinal degeneration induces an atypical gliosis of Müller cells.
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Affiliation(s)
- Ianors Iandiev
- Paul-Flechsig-Institut für Hirnforschung, Universität Leipzig, Jahnallee 59, D-04109 Leipzig, Germany.
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Wurm A, Pannicke T, Iandiev I, Wiedemann P, Reichenbach A, Bringmann A. The developmental expression of K+ channels in retinal glial cells is associated with a decrease of osmotic cell swelling. Glia 2006; 54:411-23. [PMID: 16886204 DOI: 10.1002/glia.20391] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A major function of glial cells is the control of osmotic and ionic homeostasis, mediated by K+ and water movements predominantly through inwardly rectifying K+ (Kir) and aquaporin water channels. It has been suggested that K+ currents through Kir channels are implicated in the regulation of glial cell volume. Here, we investigated whether the developmental increase in Kir channel expression in Müller glial cells of the rat retina is associated with an alteration of cell volume regulation under anisoosmotic conditions. Around the time of eye opening at postnatal day (P) 15, developing retinal glial cells fully alter the profile of their membrane conductances, from a current pattern with prominent fast transient K+ and Na+ currents to a pattern of noninactivating currents through Kir and delayed rectifier K+ channels. Concomitantly, aquaporins-1 and -4 are expressed in the developing retina. This is accompanied by a conspicuous alteration of the swelling characteristics of cells; somata of immature glial cells in early postnatal retinas (P5-P15) swell under hypotonic stress but no swelling is inducible in mature cells at P18 and thereafter. However, glial cells at all developmental stages swell when their Kir channels are blocked by Ba2+. The postnatal maturation of Kir channel currents and volume regulation in retinal glial cells is delayed by visual deprivation. The data suggest that Kir channels are crucially involved in osmotic volume homeostasis of mature glial cells, and that the absence of Kir channels in immature cells is a major cause of their insufficient volume regulation.
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Affiliation(s)
- Antje Wurm
- Paul Flechsig Institute of Brain Research, University of Leipzig Medical Faculty, Leipzig, Germany
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Pannicke T, Biedermann B, Uckermann O, Weick M, Bringmann A, Wolf S, Wiedemann P, Habermann G, Buse E, Reichenbach A. Physiological properties of retinal Muller glial cells from the cynomolgus monkey, Macaca fascicularis--a comparison to human Muller cells. Vision Res 2005; 45:1781-91. [PMID: 15797768 DOI: 10.1016/j.visres.2005.01.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2004] [Revised: 01/11/2005] [Accepted: 01/19/2005] [Indexed: 11/16/2022]
Abstract
Retinae from rabbits and laboratory rodents are often used as 'models' of the human retina, although there are anatomical differences. To test whether monkey eyes provide a better model, a physiological study of Muller glial cells was performed comparing isolated cells and retinal wholemounts from the cynomolgus monkey, Macaca fascicularis and from man. The membrane conductance of Muller cells from both species was dominated by inward and outward K(+) currents. Cells displayed glutamate uptake currents and responded to nucleotides by intracellular Ca(2+) increases. However, there were also species differences, such as a lack of GABA(A) receptors and of Ca(2+)-dependent K(+) currents in monkey cells. Thus, the use of Muller cells from cynomolgus monkeys may be advantageous for investigating a few specific properties; in general, monkey cells are no more similar to human cells than those from standard laboratory animals.
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Affiliation(s)
- Thomas Pannicke
- Paul-Flechsig-Institut für Hirnforschung, Universität Leipzig, Jahnallee 59, D-04109 Leipzig, Germany.
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Pannicke T, Uckermann O, Iandiev I, Biedermann B, Wiedemann P, Perlman I, Reichenbach A, Bringmann A. Altered membrane physiology in Müller glial cells after transient ischemia of the rat retina. Glia 2004; 50:1-11. [PMID: 15593100 DOI: 10.1002/glia.20151] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Inwardly rectifying K+ (Kir) channels have been implicated in the mediation of retinal K+ homeostasis by Muller glial cells. To assess possible involvement of altered glial K+ channel expression in ischemia-reperfusion injury, transient retinal ischemia was induced in rat eyes. Acutely isolated Muller cells from postischemic retinae displayed a fast downregulation of their Kir currents, which began within 1 day and reached a maximum at 3 days of reperfusion, with a peak decrease to 20% as compared with control. This strong decrease of Kir currents was accompanied by an increase of the incidence of cells which displayed depolarization-evoked fast transient (A-type) K+ currents. While no cell from untreated control rats expressed A-type K+ currents, all cells investigated from 3- and 7-day postischemic retinae displayed such currents. An increased incidence of cells displaying fast transient Na+ currents was observed at 7 days after ischemia. These results suggest a role of altered glial Kir channel expression in postischemic neuronal degeneration via disturbance of retinal K+ siphoning.
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Affiliation(s)
- Thomas Pannicke
- Paul-Flechsig-Institut für Hirnforschung, Abteilung Neurophysiologie, Universität Leipzig, Leipzig, Germany.
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Pannicke T, Iandiev I, Uckermann O, Biedermann B, Kutzera F, Wiedemann P, Wolburg H, Reichenbach A, Bringmann A. A potassium channel-linked mechanism of glial cell swelling in the postischemic retina. Mol Cell Neurosci 2004; 26:493-502. [PMID: 15276152 DOI: 10.1016/j.mcn.2004.04.005] [Citation(s) in RCA: 171] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2003] [Revised: 03/19/2004] [Accepted: 04/16/2004] [Indexed: 01/26/2023] Open
Abstract
The cellular mechanisms underlying glial cell swelling, a central cause of edema formation in the brain and retina, are not yet known. Here, we show that glial cells in the postischemic rat retina, but not in control retina, swell upon hypotonic stress. Swelling of control cells could be evoked when their K(+) channels were blocked. After transient ischemia, glial cells strongly downregulated their K(+) conductance and their prominent Kir4.1 protein expression at blood vessels and the vitreous body. In contrast, the expression of the aquaporin-4 (AQP4) (water channel) protein was only slightly altered after ischemia. Activation of D(2) dopaminergic receptors prevents the hypotonic glial cell swelling. The present results elucidate the coupling of transmembraneous water fluxes to K(+) currents in glial cells and reveal the role of altered K(+) channel expression in the development of cytotoxic edema. We propose a mechanism of postischemic glial cell swelling where a downregulation of their K(+) conductance prevents the emission of intracellularly accumulated K(+) ions, resulting in osmotically driven water fluxes from the blood into the glial cells via aquaporins. Inhibition of these water fluxes may be beneficial to prevent ischemia-evoked glial cell swelling.
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Affiliation(s)
- Thomas Pannicke
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany
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27
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Schopf S, Ruge H, Bringmann A, Reichenbach A, Skatchkov SN. Switch of K+ buffering conditions in rabbit retinal Müller glial cells during postnatal development. Neurosci Lett 2004; 365:167-70. [PMID: 15246541 DOI: 10.1016/j.neulet.2004.04.074] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2004] [Revised: 04/27/2004] [Accepted: 04/28/2004] [Indexed: 11/17/2022]
Abstract
Although spatial buffering of excess extracellular K+ by K+ channels is a main function of retinal glial (Müller) cells, there are severe limitations to long distance K+-spatial buffering that have been predicted for (immature) glial cells: (i) a lack of inwardly rectifying K+ (Kir) channels [Glia 21(1997) 46]; and (ii) high internal resistance of outgrowing (cable like) processes [W. Rall, Handbook of Physiology, Section 1, vol. 1, Part 1, American Physiological Society, Bethesda, 1977, pp. 39-97]. In order to determine if changes in developing Müller cells improve or worsen their capability of carrying K+ spatial buffering currents, we compared the whole-cell currents of acutely isolated Müller cells at 5, 11 and 28 postnatal days of rabbits. Both K+-spatial buffer limitations described above were found in early postnatal stage (5 days), however, the cells overcome these limitations shortly after 11 days. During the period of 11-28 days, rabbit Müller cells simultaneously increase stalk axial conductance and express Kir channels. Both processes take place during the critical stage of retinal maturation, and should dramatically improve "cable" K+-spatial buffering.
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Affiliation(s)
- Stefan Schopf
- Department of Neurophysiology, Paul Flechsig Institute of Brain Research, University of Leipzig, D-04109 Leipzig, Germany
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Chávez AE, Pannicke T, Roncagliolo M, Reichenbach A, Palacios AG. Electrophysiological properties of retinal Müller glial cells from myelin mutant rat. Glia 2003; 45:338-45. [PMID: 14966865 DOI: 10.1002/glia.10330] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The structural and functional similarities between Müller cells and oligodendrocytes prompted the present study of the electrophysiological properties of Müller (glia) cells obtained from the retinae of control and myelin mutant taiep rats during the postnatal developmental period (P12-P180). The whole-cell configuration of the patch-clamp technique was used to characterize the general properties and the K+ currents from dissociated Müller cells. During the first 3 weeks of life, a decrease of the membrane resistance and an increase of the membrane potential were observed in Müller cells from both control and taiep rats. However, Müller cells from taiep rats never achieved the very negative membrane potential (-50 mV vs -80 mV) and the low membrane resistance characteristic for control cells. Furthermore, Müller cells displayed increased inward and outward K+ currents during postnatal development up to P30/60 in controls; however, in taiep rats, this increase ceased at P20/30, and low-amplitude currents persisted into adulthood. These results provide first evidence of physiological changes in retinal Müller cells as a consequence of a myelin mutation causing a progressive deterioration of the central nervous system (CNS) due to a disturbance of the microtubule network of oligodendrocytes. We hypothesize that the progressive dysmyelination process of the optic nerve, accompanied by functional deficits of retinal neurons (e.g., ganglion cells), induces physiological alterations of Müller cells.
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Affiliation(s)
- Andrés E Chávez
- Department of Physiology, Faculty of Science, Neuroscience Center of Valparaiso, University of Valparaíso, Valparaíso, Chile
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29
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Schools GP, Zhou M, Kimelberg HK. Electrophysiologically "complex" glial cells freshly isolated from the hippocampus are immunopositive for the chondroitin sulfate proteoglycan NG2. J Neurosci Res 2003; 73:765-77. [PMID: 12949902 DOI: 10.1002/jnr.10680] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We have recently described a subgroup of isolated glial fibrillary acidic protein-positive (GFAP+) hippocampal astrocytes that predominantly express outwardly rectifying currents (which we term "ORAs" for outwardly rectifying astrocytes), which are similar to the currents already described for hippocampal GFAP- "complex glia." We now report that post-recording staining of cells that were first selected as "complex" by morphology and then confirmed by their electrophysiological characteristics were NG2+ approximately 90% of the time. Also, the morphology of freshly isolated NG2+ cells differs from that of isolated GFAP+ ORAs in having a smaller and round cell body with thinner processes, which usually are collapsed back onto the soma. Upon detailed examination, NG2+ cells were found to differ quantitatively in some electrophysiological characteristics from GFAP+ ORAs. The outward, transient K+ currents (IKa) in the NG2+ cells showed a slower decay than the IKa in ORAs, and their density decreased in NG2+ cells from older animals. The other two major cation currents, the voltage-activated Na+ and outwardly delayed rectifier K+ currents, were similar in NG2+ cells and ORAs. To further distinguish isolated complex cells from outwardly rectifying GFAP+ astrocytes, we performed immunocytochemistry for glial markers in fixed, freshly isolated rat hippocampal glia. NG2+ cells were negative for GFAP and also for the astrocytic glutamate transporters GLT-1 and GLAST. Thus the isolated hippocampal NG2+ glial cells, though having an electrophysiological phenotype similar to that of ORAs, are an immunologically and morphologically distinct glial cell population and most likely represent NG2+ cells in situ.
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Affiliation(s)
- Gary P Schools
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, New York 12208, USA
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30
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Uckermann O, Grosche J, Reichenbach A, Bringmann A. ATP-evoked calcium responses of radial glial (Müller) cells in the postnatal rabbit retina. J Neurosci Res 2002; 70:209-18. [PMID: 12271470 DOI: 10.1002/jnr.10406] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Here we show that rabbit Müller cell differentiation from radial glial progenitor cells is accompanied by a decreasing capability to respond to specific stimuli (depolarization and extracellular adenosine 5'-triphosphate [ATP]) with an elevation of intracellular calcium. Intracellular free calcium was recorded in retinal wholemounts from young (postnatal days [P] 2 to 31) and adult rabbits. Images were taken from the nerve fiber/ganglion cell layers where the endfeet of radial glial/ Müller cells can be identified after selective uptake of calcium-sensitive dyes. The area of responding endfeet was determined as the percentage of the total area occupied by Müller cell endfeet, as an estimate of the percentage of responding cells. In response to depolarization (50 mM potassium), an increase of intracellular free calcium occurred in 19% of cells from young postnatal retinae (P2-31) but only in 2% from adults. This depolarization-induced calcium rise was caused both by a calcium influx from extracellular space and by an intracellular calcium release. The latter response was inhibited by the P2 receptor blocker pyridoxal phosphate 6-azophenyl-2',4'-disulfonic acid (PPADS), indicating that extracellular calcium-independent ATP release into the extracellular space occurs during retinal depolarization. When extracellular ATP (200 microM) was applied, calcium responses were recorded in 83% of cells from young postnatal retinae (P2-6); in the course of further development, both the percentage of responding cells (7% in retinae from adult rabbits) and the amplitude of the calcium responses decreased. It is concluded that during the differentiation of immature radial glia into mature Müller cells, stimulus-evoked intracellular calcium signaling mechanisms change.
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Affiliation(s)
- Ortrud Uckermann
- Department of Neurophysiology, Paul Flechsig Institute of Brain Research, Leipzig, Federal Republic of Germany
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31
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Dystrophin Dp71 is critical for the clustered localization of potassium channels in retinal glial cells. J Neurosci 2002. [PMID: 12040037 DOI: 10.1523/jneurosci.22-11-04321.2002] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The Müller cell is the principal glial cell of the vertebrate retina. The primary conductance in Müller cells is the inwardly rectifying potassium channel Kir4.1 (BIR10 and KAB-2), which is highly concentrated at the endfeet at the vitreal border and to processes enveloping blood vessels. Such asymmetric and clustered distribution of Kir4.1 channels in Müller cells is thought to be critical for the buffering of extracellular potassium concentration in retina. Herein we investigated whether the distribution and functional properties of Kir4.1 channels are dependent on expression of the Dp71, a dystrophin isoform expressed in Müller cells. Kir4.1 distribution was determined in mouse retinal sections and whole mounts using anti-Kir4.1 antibodies and confocal microscopy. In Müller cells from wild-type mice, Kir4.1 is highly clustered in their endfeet and perivascular processes. In contrast, in Müller cells from the mdx(3Cv) mouse, which lacks the expression of Dp71, the Kir4.1 immunoreactivity is evenly distributed throughout the cell membrane. Surface expression of Kir4.1 is not affected in mdx(3Cv) Müller cells as current density of barium-sensitive inward currents in mdx(3Cv) Müller cells are not different from wild type. Focal extracellular potassium increases in isolated Müller cells shows that Kir channels in the mdx(3Cv) cells, as opposed to wild type, are less prominently concentrated in their endfeet. In summary, our data indicate that Dp71 is critical for the clustering but not membrane expression of Kir4.1 in mouse Müller cells. These results point to a new role for dystrophin in glial cells.
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Pannicke T, Bringmann A, Reichenbach A. Electrophysiological characterization of retinal Müller glial cells from mouse during postnatal development: comparison with rabbit cells. Glia 2002; 38:268-72. [PMID: 11968064 DOI: 10.1002/glia.10068] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The electrophysiology of murine Müller cells, and of their precursors, during postnatal development was investigated by using the whole-cell patch-clamp technique. Membrane potential, membrane capacitance, and expression of voltage-gated Na+ currents increased during the first 3 postnatal weeks. During the same period, the membrane resistance decreased due to an upregulation of both inward and outward K+ currents. Glutamate transporter-mediated currents increased during the first postnatal weeks, as well. In Müller (precursor) cells from rabbits, these transporter currents already achieved adult levels at postnatal day 6, the earliest stage studied. Together with the developmental time course of K+ currents, this indicates a delay in the maturation of murine Müller cells, as compared with cells from rabbit.
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Affiliation(s)
- Thomas Pannicke
- Paul-Flechsig-Institut für Hirnforschung, Universität Leipzig, Germany.
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Pannicke T, Weick M, Uckermann O, Wheeler-Schilling T, Fries JE, Reichel MB, Mohr C, Stahl T, Fluess M, Kacza J, Seeger J, Richt JA, Reichenbach A. Electrophysiological alterations and upregulation of ATP receptors in retinal glial Müller cells from rats infected with the Borna disease virus. Glia 2001; 35:213-23. [PMID: 11494412 DOI: 10.1002/glia.1086] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Infection with the neurotropic Borna disease virus (BDV) causes an immune-mediated neurological disease in a broad range of species. In addition to encephalitis, BDV-infected Lewis rats develop a retinitis histologically characterized by the loss of most retinal neurons. By contrast, the dominating retinal macroglia, the Müller cells, do not degenerate. It is known from several models of neurodegeneration that glial cells may survive but undergo significant alterations of their physiological parameters. This prompted us to study the electrophysiology and ATP-induced changes of intracellular Ca(2+)-concentration ([Ca(2+)](i)) in Müller cells from BDV-infected rat retinae. Freshly isolated cells were used for whole-cell patch-clamp recordings. Whereas neither zero current potentials nor membrane resistances showed significant alterations, the membrane capacitance increased in cells from BDV-infected rats during survival times of up to 8 months. This process was accompanied by a decrease in K(+) current densities. Müller cells from BDV-infected rats were characterized by expression of a prominent fast-inactivating A-type K(+) current which was rarely found in control cells. Moreover, the number of cells displaying Na(+) currents was slightly increased after BDV-infection. ATP evoked increases in [Ca(2+)](i) in Müller cells within retinal wholemounts of both control and BDV-infected animals. However, the number of ATP-responding isolated cells increased from 24% (age-matched controls) to 78% (cells from animals > or =18 weeks after infection). We conclude that in BDV-induced retinopathy, reactive rat Müller cells change their physiological parameters but these changes are different from those in Müller cells during proliferative vitreoretinopathy in man and rabbit.
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Affiliation(s)
- T Pannicke
- Paul-Flechsig-Institut für Hirnforschung, Universität Leipzig, Leipzig, Germany.
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