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Bugara K, Pacwa A, Smedowski A. Molecular pathways in experimental glaucoma models. Front Neurosci 2024; 18:1363170. [PMID: 38562304 PMCID: PMC10982327 DOI: 10.3389/fnins.2024.1363170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 03/05/2024] [Indexed: 04/04/2024] Open
Abstract
Glaucoma is a complex and progressive disease that primarily affects the optic nerve axons, leading to irreversible vision loss. Although the exact molecular mechanisms underlying glaucoma pathogenesis are not fully understood, it is believed that except increased intraocular pressure, a combination of genetic and environmental factors play a role in the development of the disease. Animal models have been widely used in the study of glaucoma, allowing researchers to better understand the underlying mechanisms of the disease and test potential treatments. Several molecular pathways have been implicated in the pathogenesis of glaucoma, including oxidative stress, inflammation, and excitotoxic-induced neurodegeneration. This review summarizes the most important knowledge about molecular mechanisms involved in the glaucoma development. Although much research has been done to better understand the molecular mechanisms underlying this disease, there is still much to be learned to develop effective treatments and prevent vision loss in those affected by glaucoma.
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Affiliation(s)
- Klaudia Bugara
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Katowice, Poland
| | - Anna Pacwa
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Katowice, Poland
- GlaucoTech Co., Katowice, Poland
| | - Adrian Smedowski
- GlaucoTech Co., Katowice, Poland
- Department of Ophthalmology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Katowice, Poland
- Department of Ophthalmology, Professor K. Gibinski University Clinical Center, Medical University of Silesia, Katowice, Poland
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2
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Shinozaki Y, Saito K, Kashiwagi K, Koizumi S. Ocular P2 receptors and glaucoma. Neuropharmacology 2023; 222:109302. [PMID: 36341810 DOI: 10.1016/j.neuropharm.2022.109302] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 10/08/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022]
Abstract
Adenosine triphosphate (ATP), an energy source currency in cells, is released or leaked to the extracellular space under both physiological and pathological conditions. Extracellular ATP functions as an intercellular signaling molecule through activation of purinergic P2 receptors. Ocular tissue and cells release ATP in response to physiological stimuli such as intraocular pressure (IOP), and P2 receptor activation regulates IOP elevation or reduction. Dysregulated purinergic signaling may cause abnormally elevated IOP, which is one of the major risk factors for glaucoma. Glaucoma, a leading cause of blindness worldwide, is characterized by progressive degeneration of optic nerves and retinal ganglion cells (RGCs), which are essential retinal neurons that transduce visual information to the brain. An elevation in IOP may stress RGCs and increase the risk for glaucoma pathogenesis. In the aqueous humor of human patients with glaucoma, the ATP level is significantly elevated. Such excess amount of ATP may directly cause RGC death via a specific subtype of P2 receptors. Dysregulated purinergic signaling may also trigger inflammation, oxidative stress, and excitotoxicity via activating non-neuronal cell types such as glial cells. In this review, we discussed the physiological roles of extracellular nucleotides in the ocular tissue and their potential role in the pathogenesis of glaucoma. This article is part of the Special Issue on 'Purinergic Signaling: 50 years'.
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Affiliation(s)
- Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan; Interdisciplinary Brain-Immune Research Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kozo Saito
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kenji Kashiwagi
- Department of Ophthalmology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan; Interdisciplinary Brain-Immune Research Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.
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3
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Lee K, Choi JO, Hwang A, Bae HW, Kim CY. Ciliary Neurotrophic Factor Derived From Astrocytes Protects Retinal Ganglion Cells Through PI3K/AKT, JAK/STAT, and MAPK/ERK Pathways. Invest Ophthalmol Vis Sci 2022; 63:4. [PMID: 35925584 PMCID: PMC9363680 DOI: 10.1167/iovs.63.9.4] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to investigate the roles of ciliary neurotrophic factor (CNTF) on the protective effects of astrocytes on retinal ganglion cells (RGCs). Methods Primary RGCs were isolated from neonatal rats. Oxidative stress was induced, and the effects of co-culture with astrocytes and CNTF treatment on RGCs were evaluated. The pathways commonly altered by astrocytes and CNTF were investigated. Effects of each pathway were investigated using pathway inhibitors against PI3K/AKT, JAK/STAT, and MAPK/ERK. RNA sequencing was performed to identify the genes upregulated and downregulated by CNTF treatment. Results Astrocytes improved the viability and increased β3-tubulin expression in RGCs. The concentration of CNTF increased in the RGC-astrocyte co-culture medium. The protective effects of astrocytes were abolished by neutralization with the anti-CNTF antibody; thus, CNTF may play an important role in the effects mediated by astrocytes. Furthermore, CNTF treatment alone enhanced the viability and β3-tubulin expression of RGCs and increased the population of viable RGCs under oxidative stress. The PI3K/AKT pathway was associated with both RGC viability and β3-tubulin expression. However, the JAK/STAT pathway increased the viability of RGCs, whereas the MAPK/ERK pathway was associated with β3-tubulin expression. RNA sequencing revealed the CNTF-upregulated genes associated with response to DNA damage and downregulated genes associated with photoreceptor cell differentiation. Conclusions Our data revealed protective effects of astrocyte-derived CNTF on RGCs. In addition, we showed that multiple pathways exert these protective effects and identified the novel genes involved. These results may be helpful in developing treatments for RGC injury.
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Affiliation(s)
- Kwanghyun Lee
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea.,Department of Ophthalmology, National Health Insurance Service Ilsan Hospital, Goyang, Gyeonggi-do, Republic of Korea
| | - Jin-Ok Choi
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Ahreum Hwang
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Hyoung Won Bae
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Chan Yun Kim
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea
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4
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Tworig JM, Feller MB. Müller Glia in Retinal Development: From Specification to Circuit Integration. Front Neural Circuits 2022; 15:815923. [PMID: 35185477 PMCID: PMC8856507 DOI: 10.3389/fncir.2021.815923] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 12/23/2021] [Indexed: 01/21/2023] Open
Abstract
Müller glia of the retina share many features with astroglia located throughout the brain including maintenance of homeostasis, modulation of neurotransmitter spillover, and robust response to injury. Here we present the molecular factors and signaling events that govern Müller glial specification, patterning, and differentiation. Next, we discuss the various roles of Müller glia in retinal development, which include maintaining retinal organization and integrity as well as promoting neuronal survival, synaptogenesis, and phagocytosis of debris. Finally, we review the mechanisms by which Müller glia integrate into retinal circuits and actively participate in neuronal signaling during development.
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Affiliation(s)
- Joshua M. Tworig
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
- *Correspondence: Joshua M. Tworig,
| | - Marla B. Feller
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
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5
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Danjo Y, Shinozaki Y, Natsubori A, Kubota Y, Kashiwagi K, Tanaka KF, Koizumi S. The Mlc1 Promoter Directs Müller Cell-specific Gene Expression in the Retina. Transl Vis Sci Technol 2022; 11:25. [PMID: 35040915 PMCID: PMC8764212 DOI: 10.1167/tvst.11.1.25] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Because the importance of glia in regulating brain functions has been demonstrated, genetic technologies that manipulate glial cell-specific gene expression in the brain have become essential and have made great progress. However, it is unknown whether the same strategy that is used in the brain can be applied to the retina because retinal glia differs from glia in the brain. Here, we aimed to find a method for selective gene expression in Müller cells (characteristic glial cells in the retina) and identified Mlc1 as a specific promoter of Müller cells. Methods Mlc1-tTA::Yellow-Cameleon-NanotetO/tetO (YC-Nano) mice were used as a reporter line. YC-Nano, a fluorescent protein, was ectopically expressed in the cell type controlled by the Mlc1 promotor. Immunofluorescence staining was used to identify the cell type expressing YC-Nano protein. Results YC-Nano-positive (+) signals were observed as vertical stalks in the sliced retina and spanned from the nerve fiber layer through the outer nuclear layer. The density of YC-Nano+ cells was higher around the optic nerve head and lower in the peripheral retina. The YC-Nano+ signals colocalized with vimentin, a marker of Müller cells, but not with the cell markers for blood vessels, microglia, neurons, or astrocytes. Conclusions The Mlc1 promoter allows us to manipulate gene expression in Müller cells without affecting astrocytes in the retina. Translational Relevance Gene manipulation under control of Mlc1 promoter offers novel technique to investigate the role of Müller cells.
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Affiliation(s)
- Yosuke Danjo
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.,GLIA Center, University of Yamanashi, Yamanashi, Japan
| | - Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.,GLIA Center, University of Yamanashi, Yamanashi, Japan
| | - Akiyo Natsubori
- Sleep Disorders Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Yuto Kubota
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.,GLIA Center, University of Yamanashi, Yamanashi, Japan
| | - Kenji Kashiwagi
- Department of Ophthalmology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.,GLIA Center, University of Yamanashi, Yamanashi, Japan
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6
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Hamada K, Shinozaki Y, Namekata K, Matsumoto M, Ohno N, Segawa T, Kashiwagi K, Harada T, Koizumi S. Loss of P2Y 1 receptors triggers glaucoma-like pathology in mice. Br J Pharmacol 2021; 178:4552-4571. [PMID: 34309010 DOI: 10.1111/bph.15637] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/22/2021] [Accepted: 07/16/2021] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Glaucoma, the leading cause of blindness, damages the retinal ganglion cells. Elevated intraocular pressure (IOP) is a high-risk factor for glaucoma, so topical hypotensive drugs are usually used for treatment. Because not all patients do not respond adequately to current treatments, there is a need to identify a new molecular target to reduce IOP. Here, we have assessed the role of P2Y1 receptors in mediating elevated IOP. EXPERIMENTAL APPROACH P2Y1 receptor agonist was instilled into the eyes of mice, and the IOP changes were measured by a rebound-type tonometer. Expression of P2Y1 receptors was estimated by immunohistochemistry. Ocular function was measured by a multifocal electroretinogram. KEY RESULTS A single dose of the P2Y1 receptor agonist transiently reduced IOP and such effects were absent in P2Y1 receptor-deficient (P2Y1 KO) mice. P2Y1 receptors were functionally expressed in the ciliary body, trabecular meshwork and Schlemm's canal. Activation of P2Y1 receptors negatively regulated aquaporin 4 (AQP4) function but up-regulated endothelial NOS (eNOS). P2Y1 KO mice showed chronic ocular hypertension regardless of age. P2Y1 KO mice at 3 months old showed no damage to retinal ganglion cells, whereas 12-month-old mice showed a significant loss of these cells and impairment of ocular functions. Damage to retinal ganglion cells was attenuated by chronic administration of an IOP-reducing agent. CONCLUSION AND IMPLICATIONS Activation of P2Y1 receptors reduced IOP via dual pathways including AQP4 and eNOS. Loss of P2Y1 receptors resulted in glaucomatous optic neuropathy, suggesting that P2Y1 receptors might provide an effective target in the treatment of glaucoma.
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Affiliation(s)
- Kentaro Hamada
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.,GLIA Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Mami Matsumoto
- Division of Ultrastructural Research, National Institute of Physiological Sciences, Aichi, Japan
| | - Nobuhiko Ohno
- Division of Ultrastructural Research, National Institute of Physiological Sciences, Aichi, Japan.,Department of Anatomy, Jichi Medical University, Tochigi, Japan
| | - Takahiro Segawa
- Center for Life Science Research, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kenji Kashiwagi
- Department of Ophthalmology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Takayuki Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.,GLIA Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
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7
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Shen J, Wang Y, Yao K. Protection of retinal ganglion cells in glaucoma: Current status and future. Exp Eye Res 2021; 205:108506. [PMID: 33609512 DOI: 10.1016/j.exer.2021.108506] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 01/29/2021] [Accepted: 02/12/2021] [Indexed: 02/08/2023]
Abstract
Glaucoma is a neuropathic disease that causes optic nerve damage, loss of retinal ganglion cells (RGCs), and visual field defects. Most glaucoma patients have no early signs or symptoms. Conventional pharmacological glaucoma medications and surgeries that focus on lowering intraocular pressure are not sufficient; RGCs continue to die, and the patient's vision continues to decline. Recent evidence has demonstrated that neuroprotective approaches could be a promising strategy for protecting against glaucoma. In the case of glaucoma, neuroprotection aims to prevent or slow down disease progression by mitigating RGCs death and optic nerve degeneration. Notably, new pharmacologic medications such as antiglaucomatous agents, antibiotics, dietary supplementation, novel neuroprotective molecules, neurotrophic factors, translational methods such as gene therapy and cell therapy, and electrical stimulation-based physiotherapy are emerging to attenuate the death of RGCs, or to make RGCs resilient to attacks. Understanding the roles of these interventions in RGC protection may offer benefits over traditional pharmacological medications and surgeries. In this review, we summarize the recent neuroprotective strategy for glaucoma, both in clinical trials and in laboratory research.
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Affiliation(s)
- Junhui Shen
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China; Key Laboratory of Ophthalmology of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Yuanqi Wang
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China; Key Laboratory of Ophthalmology of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Ke Yao
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China; Key Laboratory of Ophthalmology of Zhejiang Province, Hangzhou, Zhejiang, 310009, China.
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8
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Shinozaki Y, Koizumi S. Potential roles of astrocytes and Müller cells in the pathogenesis of glaucoma. J Pharmacol Sci 2020; 145:262-267. [PMID: 33602506 DOI: 10.1016/j.jphs.2020.12.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 12/12/2020] [Accepted: 12/28/2020] [Indexed: 12/26/2022] Open
Abstract
Glaucoma, a progressive optic neuropathy and the leading cause of blindness, is characterized by impairment or degeneration of retinal ganglion cells (RGCs), which transmit visual information to the brain. Currently, 70 million people worldwide are affected by glaucoma. Elevated intraocular pressure (IOP), a major risk factor of glaucoma, directly damages RGCs. However, a substantial proportion of glaucoma patients have a normal IOP level. In particular, over 90% of Japanese glaucoma patients are reported to have normal IOP levels. Thus, a new focus for glaucoma pathology has emerged. Glial cells contribute to tissue homeostasis. Under pathological conditions, glial cells become reactive, lose their homeostatic functions, and gain neurotoxic functions, which trigger neurodegeneration in several diseases including glaucoma. Reactive glial cells have been identified in the eyes of glaucoma patients. In a glaucoma animal model, reactive glial cells are observed at early stages of the disease when RGCs are intact, indicating the possible role of glial cells in the pathogenesis of glaucoma. In this review, we introduce potential roles of glial cells in the pathogenesis of glaucoma. We focus on the roles of the ocular macroglial cells such as astrocytes and Müller cells, and discuss their roles in the pathogenesis of glaucoma.
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Affiliation(s)
- Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan; Interdisciplinary Brain-Immune Research Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan; Interdisciplinary Brain-Immune Research Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.
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9
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Huang L, Otrokocsi L, Sperlágh B. Role of P2 receptors in normal brain development and in neurodevelopmental psychiatric disorders. Brain Res Bull 2019; 151:55-64. [PMID: 30721770 DOI: 10.1016/j.brainresbull.2019.01.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/17/2019] [Accepted: 01/19/2019] [Indexed: 12/19/2022]
Abstract
The purinergic signaling system, including P2 receptors, plays an important role in various central nervous system (CNS) disorders. Over the last few decades, a substantial amount of accumulated data suggest that most P2 receptor subtypes (P2X1, 2, 3, 4, 6, and 7, and P2Y1, 2, 6, 12, and 13) regulate neuronal/neuroglial developmental processes, such as proliferation, differentiation, migration of neuronal precursors, and neurite outgrowth. However, only a few of these subtypes (P2X2, P2X3, P2X4, P2X7, P2Y1, and P2Y2) have been investigated in the context of neurodevelopmental psychiatric disorders. The activation of these potential target receptors and their underlying mechanisms mainly influence the process of neuroinflammation. In particular, P2 receptor-mediated inflammatory cytokine release has been indicated to contribute to the complex mechanisms of a variety of CNS disorders. The released inflammatory cytokines could be utilized as biomarkers for neurodevelopmental and psychiatric disorders to improve the early diagnosis intervention, and prognosis. The population changes in gut microbiota after birth are closely linked to neurodevelopmental/neuropsychiatric disorders in later life; thus, the dynamic expression and function of P2 receptors on gut epithelial cells during disease processes indicate a novel avenue for the evaluation of disease progression and for the discovery of related therapeutic compounds.
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Affiliation(s)
- Lumei Huang
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary; János Szentágothai School of Neurosciences, Semmelweis University School of PhD Studies, Budapest, Hungary
| | - Lilla Otrokocsi
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Beáta Sperlágh
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
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10
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Ventura ALM, Dos Santos-Rodrigues A, Mitchell CH, Faillace MP. Purinergic signaling in the retina: From development to disease. Brain Res Bull 2018; 151:92-108. [PMID: 30458250 DOI: 10.1016/j.brainresbull.2018.10.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/14/2018] [Accepted: 10/23/2018] [Indexed: 02/07/2023]
Abstract
Retinal injuries and diseases are major causes of human disability involving vision impairment by the progressive and permanent loss of retinal neurons. During development, assembly of this tissue entails a successive and overlapping, signal-regulated engagement of complex events that include proliferation of progenitors, neurogenesis, cell death, neurochemical differentiation and synaptogenesis. During retinal damage, several of these events are re-activated with both protective and detrimental consequences. Purines and pyrimidines, along with their metabolites are emerging as important molecules regulating both retinal development and the tissue's responses to damage. The present review provides an overview of the purinergic signaling in the developing and injured retina. Recent findings on the presence of vesicular and channel-mediated ATP release by retinal and retinal pigment epithelial cells, adenosine synthesis and release, expression of receptors and intracellular signaling pathways activated by purinergic signaling in retinal cells are reported. The pathways by which purinergic receptors modulate retinal cell proliferation, migration and death of retinal cells during development and injury are summarized. The contribution of nucleotides to the self-repair of the injured zebrafish retina is also discussed.
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Affiliation(s)
- Ana Lucia Marques Ventura
- Department of Neurobiology, Neuroscience Program, Fluminense Federal University, Niterói, RJ, Brazil.
| | | | - Claire H Mitchell
- Department of Anatomy and Cell Biology, Ophthalmology, and Physiology, University of Pennsylvania, Philadelphia, PA 19104, United States.
| | - Maria Paula Faillace
- Instituto de Fisiología y Biofísica Prof. Bernardo Houssay (IFIBIO-Houssay), Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina; Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
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11
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Takeda A, Shinozaki Y, Kashiwagi K, Ohno N, Eto K, Wake H, Nabekura J, Koizumi S. Microglia mediate non-cell-autonomous cell death of retinal ganglion cells. Glia 2018; 66:2366-2384. [PMID: 30375063 DOI: 10.1002/glia.23475] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 05/23/2018] [Accepted: 05/28/2018] [Indexed: 12/22/2022]
Abstract
Excitotoxicity is well known in the neuronal death in the brain and is also linked to neuronal damages in the retina. Recent accumulating evidence show that microglia greatly affect excitotoxicity in the brain, but their roles in retina have received only limited attention. Here, we report that retinal excitotoxicity is mediated by microglia. To this end, we employed three discrete methods, that is, pharmacological inhibition of microglia by minocycline, pharmacological ablation by an antagonist for colony stimulating factor 1 receptor (PLX5622), and genetic ablation of microglia using Iba1-tTA::DTAtetO/tetO mice. Intravitreal injection of NMDA increased the number of apoptotic retinal ganglion cells (RGCs) followed by reduction in the number of RGCs. Although microglia did not respond to NMDA directly, they became reactive earlier than RGC damages. Inhibition or ablation of microglia protected RGCs against NMDA. We found up-regulation of proinflammatory cytokine genes including Il1b, Il6 and Tnfa, among which Tnfa was selectively blocked by minocycline. PLX5622 also suppressed Tnfa expression. Tumor necrosis factor α (TNFα) signals were restricted in microglia at very early followed by spreading into other cell types. TNFα up-regulation in microglia and other cells were significantly attenuated by minocycline and PLX5622, suggesting a central role of microglia for TNFα induction. Both inhibition of TNFα and knockdown of TNF receptor type 1 by siRNA protected RGCs against NMDA. Taken together, our data demonstrate that a phenotypic change of microglia into a neurotoxic one is a critical event for the NMDA-induced degeneration of RGCs, suggesting an importance of non-cell-autonomous mechanism in the retinal neuronal excitotoxicity.
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Affiliation(s)
- Akiko Takeda
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kenji Kashiwagi
- Department of Ophthalmology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Nobuhiko Ohno
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences (NIPS), Aichi, Japan.,Department of Anatomy, Jichi Medical University, Tochigi, Japan
| | - Kei Eto
- Division of Homeostatic Development, NIPS, Aichi, Japan
| | - Hiroaki Wake
- Division of Homeostatic Development, NIPS, Aichi, Japan.,Division of System Neuroscience, Graduate School of Medicine, Kobe University, Hyogo, Japan.,Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Saitama, Japan
| | | | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
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12
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Jacob TF, Singh V, Dixit M, Ginsburg-Shmuel T, Fonseca B, Pintor J, Youdim MBH, Major DT, Weinreb O, Fischer B. A promising drug candidate for the treatment of glaucoma based on a P2Y6-receptor agonist. Purinergic Signal 2018; 14:271-284. [PMID: 30019187 DOI: 10.1007/s11302-018-9614-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 05/31/2018] [Indexed: 11/28/2022] Open
Abstract
Extracellular nucleotides can regulate the production/drainage of the aqueous humor via activation of P2 receptors, thus affecting the intraocular pressure (IOP). We evaluated 5-OMe-UDP(α-B), 1A, a potent P2Y6-receptor agonist, for reducing IOP and treating glaucoma. Cell viability in the presence of 1A was measured using [3-(4, 5-dimethyl-thiazol-2-yl) 2, 5-diphenyl-tetrazolium bromide] (MTT) assay in rabbit NPE ciliary non-pigmented and corneal epithelial cells, human retinoblastoma, and liver Huh7 cells. The effect of 1A on IOP was determined in acute glaucomatous rabbit hyaluronate model and phenol-induced chronic glaucomatous rabbit model. The origin of activity of 1A was investigated by generation of a homology model of hP2Y6-R and docking studies. 1A did not exert cytotoxic effects up to 100 mM vs. trusopt and timolol in MTT assay in ocular and liver cells. In normotensive rabbits, 100 μM 1A vs. xalatan, trusopt, and pilocarpine reduced IOP by 45 vs. 20-30%, respectively. In the phenol animal model, 1A (100 μM) showed reduction of IOP by 40 and 20%, following early and late administration, respectively. Docking results suggest that the high activity and selectivity of 1A is due to intramolecular interaction between Pα-BH3 and C5-OMe which positions 1A in a most favorable site inside the receptor. P2Y6-receptor agonist 1A effectively and safely reduces IOP in normotense, acute, and chronic glaucomatous rabbits, and hence may be suggested as a novel approach for the treatment of glaucoma.
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Affiliation(s)
- Tali Fishman Jacob
- GlaucoPharm Ltd, P.O.Box 620, New Industrial Park, 20692, Yokneam, Israel
| | - Vijay Singh
- Department of Chemistry, Gonda-Goldschmied Medical Research Center, Bar-Ilan University, 52900, Ramat Gan, Israel
| | - Mudit Dixit
- Department of Chemistry, Gonda-Goldschmied Medical Research Center, Bar-Ilan University, 52900, Ramat Gan, Israel
| | - Tamar Ginsburg-Shmuel
- Department of Chemistry, Gonda-Goldschmied Medical Research Center, Bar-Ilan University, 52900, Ramat Gan, Israel
| | - Begoña Fonseca
- Escuela Universitaria De Optica, Universidad Complutense De Madrid, C/Arcos De Jalon 118, 28037, Madrid, Spain
| | - Jesus Pintor
- Escuela Universitaria De Optica, Universidad Complutense De Madrid, C/Arcos De Jalon 118, 28037, Madrid, Spain
| | - Moussa B H Youdim
- GlaucoPharm Ltd, P.O.Box 620, New Industrial Park, 20692, Yokneam, Israel
| | - Dan T Major
- Department of Chemistry, Gonda-Goldschmied Medical Research Center, Bar-Ilan University, 52900, Ramat Gan, Israel.
| | - Orly Weinreb
- GlaucoPharm Ltd, P.O.Box 620, New Industrial Park, 20692, Yokneam, Israel.
| | - Bilha Fischer
- Department of Chemistry, Gonda-Goldschmied Medical Research Center, Bar-Ilan University, 52900, Ramat Gan, Israel.
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Identification of proteins associated with clinical and pathological features of proliferative diabetic retinopathy in vitreous and fibrovascular membranes. PLoS One 2017; 12:e0187304. [PMID: 29095861 PMCID: PMC5667868 DOI: 10.1371/journal.pone.0187304] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 10/16/2017] [Indexed: 01/17/2023] Open
Abstract
Purpose To identify the protein profiles in vitreous associated with retinal fibrosis, angiogenesis, and neurite formation in epiretinal fibrovascular membranes (FVMs) in patients with proliferative diabetic retinopathy (PDR). Methods Vitreous samples of 5 non-diabetic control patients with vitreous debris and 7 patients with PDR membranes were screened for 507 preselected proteins using the semi-quantitative RayBio® L-series 507 antibody array. From this array, 60 proteins were selected for a custom quantitative antibody array (Raybiotech, Human Quantibody® array), analyzing 7 control patients, 8 PDR patients with FVMs, and 5 PDR patients without FVMs. Additionally, mRNA levels of proteins of interest were measured in 10 PDR membranes and 11 idiopathic membranes and in retinal tissues and cells to identify possible sources of protein production. Results Of the 507 proteins screened, 21 were found to be significantly elevated in PDR patients, including neurogenic and angiogenic factors such as neuregulin 1 (NRG1), nerve growth factor receptor (NGFR), placental growth factor (PlGF) and platelet derived growth factor (PDGF). Angiopoietin-2 (Ang2) concentrations were strongly correlated to the degree of fibrosis and the presence of FVMs in patients with PDR. Protein correlation analysis showed PDGF to be extensively co-regulated with other proteins, including thrombospondin-1 and Ang2. mRNA levels of glial-derived and brain/derived neurotrophic factor (GDNF and BDNF) were elevated in PDR membranes. These results were validated in a second study of 52 vitreous samples of 32 PDR patients and 20 control patients. Conclusions This exploratory study reveals protein networks that potentially contribute to neurite outgrowth, angiogenesis and fibrosis in the formation of fibrovascular membranes in PDR. We identified a possible role of Ang2 in fibrosis and the formation of FVMs, and of the neurotrophic factors NRG1, PDGF and GDNF in neurite growth that occurs in all FVMs in PDR.
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Shinozaki Y, Kashiwagi K, Namekata K, Takeda A, Ohno N, Robaye B, Harada T, Iwata T, Koizumi S. Purinergic dysregulation causes hypertensive glaucoma-like optic neuropathy. JCI Insight 2017; 2:93456. [PMID: 28978804 DOI: 10.1172/jci.insight.93456] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 08/24/2017] [Indexed: 12/24/2022] Open
Abstract
Glaucoma is an optic neuropathy characterized by progressive degeneration of retinal ganglion cells (RGCs) and visual loss. Although one of the highest risk factors for glaucoma is elevated intraocular pressure (IOP) and reduction in IOP is the only proven treatment, the mechanism of IOP regulation is poorly understood. We report that the P2Y6 receptor is critical for lowering IOP and that ablation of the P2Y6 gene in mice (P2Y6KO) results in hypertensive glaucoma-like optic neuropathy. Topically applied uridine diphosphate, an endogenous selective agonist for the P2Y6 receptor, decreases IOP. The P2Y6 receptor was expressed in nonpigmented epithelial cells of the ciliary body and controlled aqueous humor dynamics. P2Y6KO mice exhibited sustained elevation of IOP, age-dependent damage to the optic nerve, thinning of ganglion cell plus inner plexiform layers, and a reduction of RGC numbers. These changes in P2Y6KO mice were attenuated by an IOP lowering agent. Consistent with RGC damage, visual functions were impaired in middle-aged P2Y6KO mice. We also found that expression and function of P2Y6 receptors in WT mice were significantly reduced by aging, another important risk factor for glaucoma. In summary, our data show that dysfunctional purinergic signaling causes IOP dysregulation, resulting in glaucomatous optic neuropathy.
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Affiliation(s)
- Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, and
| | - Kenji Kashiwagi
- Department of Ophthalmology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Akiko Takeda
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, and
| | - Nobuhiko Ohno
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Bernard Robaye
- Institute of Interdisciplinary Research and.,Institute of Biology and Molecular Medicine, Université Libre de Bruxelles, Belgium
| | - Takayuki Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takeshi Iwata
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, and
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15
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Jacobson KA, Civan MM. Ocular Purine Receptors as Drug Targets in the Eye. J Ocul Pharmacol Ther 2016; 32:534-547. [PMID: 27574786 PMCID: PMC5069731 DOI: 10.1089/jop.2016.0090] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 07/13/2016] [Indexed: 02/06/2023] Open
Abstract
Agonists and antagonists of various subtypes of G protein coupled adenosine receptors (ARs), P2Y receptors (P2YRs), and ATP-gated P2X receptor ion channels (P2XRs) are under consideration as agents for the treatment of ocular diseases, including glaucoma and dry eye. Numerous nucleoside and nonnucleoside modulators of the receptors are available as research tools and potential therapeutic molecules. Three of the 4 subtypes of ARs have been exploited with clinical candidate molecules for treatment of the eye: A1, A2A, and A3. An A1AR agonist is in clinical trials for glaucoma, A2AAR reduces neuroinflammation, A3AR protects retinal ganglion cells from apoptosis, and both A3AR agonists and antagonists had been reported to lower intraocular pressure (IOP). Extracellular concentrations of endogenous nucleotides, including dinucleoside polyphosphates, are increased in pathological states, activating P2Y and P2XRs throughout the eye. P2YR agonists, including P2Y2 and P2Y6, lower IOP. Antagonists of the P2X7R prevent the ATP-induced neuronal apoptosis in the retina. Thus, modulators of the purinome in the eye might be a source of new therapies for ocular diseases.
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Affiliation(s)
- Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Mortimer M. Civan
- Departments of Physiology and Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
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