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Chiha W, Bartlett CA, Petratos S, Fitzgerald M, Harvey AR. Intravitreal application of AAV-BDNF or mutant AAV-CRMP2 protects retinal ganglion cells and stabilizes axons and myelin after partial optic nerve injury. Exp Neurol 2020; 326:113167. [PMID: 31904385 DOI: 10.1016/j.expneurol.2019.113167] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/20/2019] [Accepted: 12/31/2019] [Indexed: 12/29/2022]
Abstract
Secondary degeneration following an initial injury to the central nervous system (CNS) results in increased tissue loss and is associated with increasing functional impairment. Unilateral partial dorsal transection of the adult rat optic nerve (ON) has proved to be a useful experimental model in which to study factors that contribute to secondary degenerative events. Using this injury model, we here quantified the protective effects of intravitreally administered bi-cistronic adeno-associated viral (AAV2) vectors encoding either brain derived neurotrophic factor (BDNF) or a mutant, phospho-resistant, version of collapsin response mediator protein 2 (CRMP2T555A) on retinal ganglion cells (RGCs), their axons, and associated myelin. To test for potential synergistic interactions, some animals received combined injections of both vectors. Three months post-injury, all treatments maintained RGC numbers in central retina, but only AAV2-BDNF significantly protected ventrally located RGCs exclusively vulnerable to secondary degeneration. Behaviourally, treatments that involved AAV2-BDNF significantly restored the number of smooth-pursuit phases of optokinetic nystagmus. While all therapeutic regimens preserved axonal density and proportions of typical complexes, including heminodes and single nodes, BDNF treatments were generally more effective in maintaining the length of the node of Ranvier in myelin surrounding ventral ON axons after injury. Both AAV2-BDNF and AAV2-CRMP2T555A prevented injury-induced changes in G-ratio and overall myelin thickness, but only AAV2-BDNF administration protected against large-scale myelin decompaction in ventral ON. In summary, in a model of secondary CNS degeneration, both BDNF and CRMP2T555A vectors were neuroprotective, however different efficacies were observed for these overexpressed proteins in the retina and ON, suggesting disparate cellular and molecular targets driving responses for neural repair. The potential use of these vectors to treat other CNS injuries and pathologies is discussed.
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Affiliation(s)
- Wissam Chiha
- School of Biological Sciences, The University of Western Australia, WA 6009, Australia; Curtin Health Innovation Research Institute, Curtin University, Belmont, WA 6102, Australia
| | - Carole A Bartlett
- School of Biological Sciences, The University of Western Australia, WA 6009, Australia
| | - Steven Petratos
- Department of Neuroscience, Monash University, VIC 3004, Australia
| | - Melinda Fitzgerald
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia; Curtin Health Innovation Research Institute, Curtin University, Belmont, WA 6102, Australia
| | - Alan R Harvey
- School of Human Sciences, The University of Western Australia, WA 6009, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia.
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Quan Y, Wu Y, Zhan Z, Yang Y, Chen X, Wu K, Yu M. Inhibition of the leucine-rich repeat protein lingo-1 enhances RGC survival in optic nerve injury. Exp Ther Med 2019; 19:619-629. [PMID: 31885701 PMCID: PMC6913235 DOI: 10.3892/etm.2019.8250] [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: 07/03/2018] [Accepted: 03/26/2019] [Indexed: 01/02/2023] Open
Abstract
Leucine-rich repeat and immunoglobulin-like domain-containing nogo receptor-interacting protein 1 (lingo-1) is selectively expressed on neurons and oligodendrocytes in the central nervous system and acts as a negative regulator in neural repair, implying a potential role in optic neuropathy. The aim of the present study was to determine whether adeno-associated virus serotype 2 (AAV2) vector-mediated transfer of lingo-1 short hairpin RNA could reduce nerve crush-induced axonal degeneration and enhance axonal regeneration following optic nerve (ON) injury in vivo. The expression of lingo-1 was knocked down in vivo using a green fluorescent protein (GFP)-tagged AAV2 encoding lingo-1 shRNA via intravitreal injection in adult Sprague-Dawley rats. Silencing effects of AAV2-lingo-1-shRNA were confirmed by detecting GFP labelling of RGCs, and by quantifying lingo-1 expression levels with reverse transcription-quantitative polymerase chain reaction and western blotting. Rats received an intravitreal injection of AAV2-lingo-1-shRNA or negative control shRNA. The ON crush (ONC) injury was performed 2 weeks after the intravitreal injection. RGC density, lesion volume of the injured ON and the visual electrophysiology [flash visual evoked potential (F-VEP)] at different time points post-injury were determined. Transduction with lingo-1-shRNA decreased lingo-1 expression levels and promoted RGC survival following ONC. Lingo-1-shRNA promoted ON tissue repair and functional recovery. The mechanism underlying the effect of AAV2-lingo-1-shRNA on RGCs may be the phosphorylation of protein kinase B (Akt) at Ser473 and activation of the Akt signaling pathway acting downstream of lingo-1. The results of the current study indicate that the inhibition of lingo-1 may enhance RGC survival and facilitate functional recovery following ON injury, representing a promising potential strategy for the repair of optic neuropathy.
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Affiliation(s)
- Yadan Quan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Yali Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Zongyi Zhan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Yangfan Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Xiaotao Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Kaili Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510060, P.R. China
| | - Minbin Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong 510060, P.R. China
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Therapeutic Strategies for Attenuation of Retinal Ganglion Cell Injury in Optic Neuropathies: Concepts in Translational Research and Therapeutic Implications. BIOMED RESEARCH INTERNATIONAL 2019; 2019:8397521. [PMID: 31828134 PMCID: PMC6885158 DOI: 10.1155/2019/8397521] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 10/07/2019] [Accepted: 10/28/2019] [Indexed: 12/19/2022]
Abstract
Retinal ganglion cell (RGC) death is the central and irreversible endpoint of optic neuropathies. Current management of optic neuropathies and glaucoma focuses on intraocular pressure-lowering treatment which is insufficient. As such, patients are effectively condemned to irreversible visual impairment. This review summarizes experimental treatments targeting RGCs over the last decade. In particular, we examine the various treatment modalities and determine their viability and limitations in translation to clinical practice. Experimental RGC treatment can be divided into (1) cell replacement therapy, (2) neuroprotection, and (3) gene therapy. For cell replacement therapy, difficulties remain in successfully integrating transplanted RGCs from various sources into the complex neural network of the human retina. However, there is significant potential for achieving full visual restoration with this technique. Neuroprotective strategies, in the form of pharmacological agents, nutritional supplementation, and neurotrophic factors, are viable strategies with encouraging results from preliminary noncomparative interventional case series. It is important to note, however, that most published studies are focused on glaucoma, with few treating optic neuropathies of other etiologies. Gene therapy, through the use of viral vectors, has shown promising results in clinical trials, particularly for diseases with specific genetic mutations like Leber's hereditary optic neuropathy. This treatment technique can be further extended to nonhereditary diseases, through transfer of genes promoting cell survival and neuroprotection. Crucially though, for gene therapy, teratogenicity remains a significant issue in translation to clinical practice.
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Thorsdottir D, Cruickshank NC, Einwag Z, Hennig GW, Erdos B. BDNF downregulates β-adrenergic receptor-mediated hypotensive mechanisms in the paraventricular nucleus of the hypothalamus. Am J Physiol Heart Circ Physiol 2019; 317:H1258-H1271. [PMID: 31603352 DOI: 10.1152/ajpheart.00478.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Brain-derived neurotrophic factor (BDNF) is upregulated in the paraventricular nucleus of the hypothalamus (PVN) in response to hypertensive stimuli such as stress and hyperosmolality, and BDNF acting in the PVN plays a key role in elevating sympathetic activity and blood pressure. However, downstream mechanisms mediating these effects remain unclear. We tested the hypothesis that BDNF increases blood pressure, in part by diminishing inhibitory hypotensive input from nucleus of the solitary tract (NTS) catecholaminergic neurons projecting to the PVN. Male Sprague-Dawley rats received bilateral PVN injections of viral vectors expressing either green fluorescent protein (GFP) or BDNF and bilateral NTS injections of vehicle or anti-dopamine-β-hydroxylase-conjugated saporin (DSAP), a neurotoxin that selectively lesions noradrenergic and adrenergic neurons. BDNF overexpression in the PVN without NTS lesioning significantly increased mean arterial pressure (MAP) in awake animals by 18.7 ± 1.8 mmHg. DSAP treatment also increased MAP in the GFP group, by 9.8 ± 3.2 mmHg, but failed to affect MAP in the BDNF group, indicating a BDNF-induced loss of NTS catecholaminergic hypotensive effects. In addition, in α-chloralose-urethane-anesthetized rats, hypotensive responses to PVN injections of the β-adrenergic agonist isoprenaline were significantly attenuated by BDNF overexpression, whereas PVN injections of phenylephrine had no effect on blood pressure. BDNF treatment was also found to significantly reduce β1-adrenergic receptor mRNA expression in the PVN, whereas expression of other adrenergic receptors was unaffected. In summary, increased BDNF expression in the PVN elevates blood pressure, in part by downregulating β-receptor signaling and diminishing hypotensive catecholaminergic input from the NTS to the PVN.NEW & NOTEWORTHY We have shown that BDNF, a key hypothalamic regulator of blood pressure, disrupts catecholaminergic signaling between the NTS and the PVN by reducing the responsiveness of PVN neurons to inhibitory hypotensive β-adrenergic input from the NTS. This may be occurring partly via BDNF-mediated downregulation of β1-adrenergic receptor expression in the PVN and results in an increase in blood pressure.
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Affiliation(s)
| | | | - Zachary Einwag
- Department of Pharmacology, University of Vermont, Burlington, Vermont
| | - Grant W Hennig
- Department of Pharmacology, University of Vermont, Burlington, Vermont
| | - Benedek Erdos
- Department of Pharmacology, University of Vermont, Burlington, Vermont
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56
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Inducible rodent models of glaucoma. Prog Retin Eye Res 2019; 75:100799. [PMID: 31557521 DOI: 10.1016/j.preteyeres.2019.100799] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 09/16/2019] [Accepted: 09/18/2019] [Indexed: 11/23/2022]
Abstract
Glaucoma is one of the leading causes of vision impairment worldwide. In order to further understand the molecular pathobiology of this disease and to develop better therapies, clinically relevant animal models are necessary. In recent years, both the rat and mouse have become popular models in glaucoma research. Key reasons are: many important biological similarities shared among rodent eyes and the human eye; development of improved methods to induce glaucoma and to evaluate glaucomatous damage; availability of genetic tools in the mouse; as well as the relatively low cost of rodent studies. Commonly studied rat and mouse glaucoma models include intraocular pressure (IOP)-dependent and pressure-independent models. The pressure-dependent models address the most important risk factor of elevated IOP, whereas the pressure-independent models assess "normal tension" glaucoma and other "non-IOP" related factors associated with glaucomatous damage. The current article provides descriptions of these models, their characterizations, specific techniques to induce glaucoma, mechanisms of injury, advantages, and limitations.
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Khatib TZ, Martin KR. Neuroprotection in Glaucoma: Towards Clinical Trials and Precision Medicine. Curr Eye Res 2019; 45:327-338. [PMID: 31475591 DOI: 10.1080/02713683.2019.1663385] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Purpose: The eye is currently at the forefront of translational medicine and therapeutics. However, despite advances in technology, primary open-angle glaucoma remains the leading cause of irreversible blindness worldwide. Traditional intraocular pressure (IOP)-lowering therapies are often not sufficient to prevent progression to blindness, even in patients with access to high-quality healthcare. Neuroprotection strategies, which aim to boost the ability of target cells to withstand a pathological insult, have shown significant promise in animal models but none have shown clinically relevant efficacy in human clinical trials to date. We sought to evaluate the current status of neuroprotection clinical trials for glaucoma and identify limitations which have prevented translation of new glaucoma therapies to date.Methods: Literature searches identified English language references. Sources included MEDLINE, EMBASE, the Cochrane Library and Web of Science databases; reference lists of retrieved studies; and internet pages of relevant organisations, meetings and conference proceedings, and clinical trial registries.Results: We discuss six key neuroprotective strategies for glaucoma that have reached the clinical trial stage. Delivery of neurotrophic factors through gene therapy is also progressing towards glaucoma clinical trials. Refinements in trial design and the use of new modalities to define structural and functional endpoints may improve our assessment of disease activity and treatment efficacy. Advances in our understanding of compartmentalised glaucomatous degeneration and continued progress in the molecular profiling of glaucoma patients will enable us to predict individual risk and tailor treatment.Conclusion: New approaches to future glaucoma neuroprotection trials could improve the prospects for new glaucoma therapies. Glaucoma treatment tailored according to an individual's unique risk profile may become increasingly common in the future.
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Affiliation(s)
- Tasneem Z Khatib
- John Van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Eye Department, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.,Medical Sciences Division, University of Oxford, Oxford, UK
| | - Keith R Martin
- John Van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Eye Department, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.,Cambridge NIHR Biomedical Research Centre, Cambridge, UK.,Wellcome Trust - 5 MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Australia.,Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
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58
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Tsai T, Reinehr S, Maliha AM, Joachim SC. Immune Mediated Degeneration and Possible Protection in Glaucoma. Front Neurosci 2019; 13:931. [PMID: 31543759 PMCID: PMC6733056 DOI: 10.3389/fnins.2019.00931] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 08/19/2019] [Indexed: 12/13/2022] Open
Abstract
The underlying pathomechanisms for glaucoma, one of the most common causes of blindness worldwide, are still not identified. In addition to increased intraocular pressure (IOP), oxidative stress, excitotoxicity, and immunological processes seem to play a role. Several pharmacological or molecular/genetic methods are currently investigated as treatment options for this disease. Altered autoantibody levels were detected in serum, aqueous humor, and tissue sections of glaucoma patients. To further analyze the role of the immune system, an IOP-independent, experimental autoimmune glaucoma (EAG) animal model was developed. In this model, immunization with ocular antigens leads to antibody depositions, misdirected T-cells, retinal ganglion cell death and degeneration of the optic nerve, similar to glaucomatous degeneration in patients. Moreover, an activation of the complement system and microglia alterations were identified in the EAG as well as in ocular hypertension models. The inhibition of these factors can alleviate degeneration in glaucoma models with and without high IOP. Currently, several neuroprotective approaches are tested in distinct models. It is necessary to have systems that cover underlying pathomechanisms, but also allow for the screening of new drugs. In vitro models are commonly used, including single cell lines, mixed-cultures, and even organoids. In ex vivo organ cultures, pathomechanisms as well as therapeutics can be investigated in the whole retina. Furthermore, animal models reveal insights in the in vivo situation. With all these models, several possible new drugs and therapy strategies were tested in the last years. For example, hypothermia treatment, neurotrophic factors or the blockage of excitotoxity. However, further studies are required to reveal the pressure independent pathomechanisms behind glaucoma. There is still an open issue whether immune mechanisms directly or indirectly trigger cell death pathways. Hence, it might be an imbalance between protective and destructive immune mechanisms. Moreover, identified therapy options have to be evaluated in more detail, since deeper insights could lead to better treatment options for glaucoma patients.
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Affiliation(s)
| | | | | | - Stephanie C. Joachim
- Experimental Eye Research, University Eye Hospital, Ruhr-University Bochum, Bochum, Germany
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59
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Das M, Tang X, Mohapatra SS, Mohapatra S. Vision impairment after traumatic brain injury: present knowledge and future directions. Rev Neurosci 2019; 30:305-315. [PMID: 30226209 DOI: 10.1515/revneuro-2018-0015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 06/15/2018] [Indexed: 01/23/2023]
Abstract
Traumatic brain injury (TBI) is a major cause of mortality and morbidity in the USA as well as in the world. As a result of TBI, the visual system is also affected often causing complete or partial visual loss, which in turn affects the quality of life. It may also lead to ocular motor dysfunction, defective accommodation, and impaired visual perception. As a part of the therapeutic strategy, early rehabilitative optometric intervention is important. Orthoptic therapy, medication, stem cell therapy, motor and attention trainings are the available treatment options. Gene therapy is one of the most promising emerging strategies. Use of state-of-the-art nanomedicine approaches to deliver drug(s) and/or gene(s) might enhance the therapeutic efficacy of the present and future modalities. More research is needed in these fields to improve the outcome of this debilitating condition. This review focuses on different visual pathologies caused by TBI, advances in pre-clinical and clinical research, and available treatment options.
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Affiliation(s)
- Mahasweta Das
- James A. Haley Veterans Administration Hospital, Tampa, FL 33612, USA.,Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL 33612, USA
| | - Xiaolan Tang
- James A. Haley Veterans Administration Hospital, Tampa, FL 33612, USA.,Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL 33612, USA
| | - Shyam S Mohapatra
- James A. Haley Veterans Administration Hospital, Tampa, FL 33612, USA.,Department of Internal Medicine, University of South Florida College of Medicine, Tampa, FL 33612, USA
| | - Subhra Mohapatra
- James A. Haley Veterans Administration Hospital, Tampa, FL 33612, USA.,Department of Molecular Medicine, University of South Florida College of Medicine, Tampa, FL 33612, USA
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The “Use It or Lose It” Dogma in the Retina: Visual Stimulation Promotes Protection Against Retinal Ischemia. Mol Neurobiol 2019; 57:435-449. [DOI: 10.1007/s12035-019-01715-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 07/18/2019] [Indexed: 01/12/2023]
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61
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Geeraerts E, Claes M, Dekeyster E, Salinas-Navarro M, De Groef L, Van den Haute C, Scheyltjens I, Baekelandt V, Arckens L, Moons L. Optogenetic Stimulation of the Superior Colliculus Confers Retinal Neuroprotection in a Mouse Glaucoma Model. J Neurosci 2019; 39:2313-2325. [PMID: 30655352 PMCID: PMC6433760 DOI: 10.1523/jneurosci.0872-18.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 11/15/2018] [Accepted: 12/29/2018] [Indexed: 12/12/2022] Open
Abstract
Glaucoma is characterized by a progressive loss of retinal ganglion cells (RGCs) in the eye, which ultimately results in visual impairment or even blindness. Because current therapies often fail to halt disease progression, there is an unmet need for novel neuroprotective therapies to support RGC survival. Various research lines suggest that visual target centers in the brain support RGC functioning and survival. Here, we explored whether increasing neuronal activity in one of these projection areas could improve survival of RGCs in a mouse glaucoma model. Prolonged activation of an important murine RGC target area, the superior colliculus (SC), was established via a novel optogenetic stimulation paradigm. By leveraging the unique channel kinetics of the stabilized step function opsin (SSFO), protracted stimulation of the SC was achieved with only a brief light pulse. SSFO-mediated collicular stimulation was confirmed by immunohistochemistry for the immediate-early gene c-Fos and behavioral tracking, which both demonstrated consistent neuronal activity upon repeated stimulation. Finally, the neuroprotective potential of optogenetic collicular stimulation was investigated in mice of either sex subjected to a glaucoma model and a 63% reduction in RGC loss was found. This work describes a new paradigm for optogenetic collicular stimulation and a first demonstration that increasing target neuron activity can increase survival of the projecting neurons.SIGNIFICANCE STATEMENT Despite glaucoma being a leading cause of blindness and visual impairment worldwide, no curative therapies exist. This study describes a novel paradigm to reduce retinal ganglion cell (RGC) degeneration underlying glaucoma. Building on previous observations that RGC survival is supported by the target neurons to which they project and using an innovative optogenetic approach, we increased neuronal activity in the mouse superior colliculus, a main projection target of rodent RGCs. This proved to be efficient in reducing RGC loss in a glaucoma model. Our findings establish a new optogenetic paradigm for target stimulation and encourage further exploration of the molecular signaling pathways mediating retrograde neuroprotective communication.
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Affiliation(s)
- Emiel Geeraerts
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Marie Claes
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Eline Dekeyster
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Manuel Salinas-Navarro
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Lies De Groef
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Chris Van den Haute
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
- Laboratory for Neurobiology and Gene Therapy, Department of Neurosciences, KU Leuven, 3000 Leuven, Belgium
- Viral Vector Core Leuven, KU Leuven, 3000 Leuven, Belgium, and
| | - Isabelle Scheyltjens
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
- Laboratory of Neuroplasticity and Neuroproteomics, Department of Biology; KU Leuven, 3000 Leuven, Belgium
| | - Veerle Baekelandt
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
- Laboratory for Neurobiology and Gene Therapy, Department of Neurosciences, KU Leuven, 3000 Leuven, Belgium
| | - Lutgarde Arckens
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
- Laboratory of Neuroplasticity and Neuroproteomics, Department of Biology; KU Leuven, 3000 Leuven, Belgium
| | - Lieve Moons
- Laboratory of Neural Circuit Development and Regeneration, Department of Biology, KU Leuven, 3000 Leuven, Belgium,
- Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
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Inanc Tekin M, Sekeroglu MA, Demirtas C, Tekin K, Doguizi S, Bayraktar S, Yilmazbas P. Brain-Derived Neurotrophic Factor in Patients With Age-Related Macular Degeneration and Its Correlation With Retinal Layer Thicknesses. Invest Ophthalmol Vis Sci 2019; 59:2833-2840. [PMID: 30025135 DOI: 10.1167/iovs.18-24030] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To determine brain-derived neurotrophic factor (BDNF) levels in serum and aqueous humor (AH) and to assess the relationship between BDNF levels and retinal layer thicknesses in age-related macular degeneration (AMD). Methods A total of 48 AMD patients (AMD group) that was composed of twenty-three nonexudative and 25 exudative patients and 26 control subjects (control group) were included in the study. Serum and AH BDNF levels were assessed by ELISA method. Retinal layer thicknesses were calculated by segmentation analysis of optical coherence tomography. Results The mean BDNF levels in AH were found to be significantly lower in both the nonexudative and exudative AMD groups than in the control group (P = 0.003 and P < 0.001, respectively). Optical coherence tomography segmentation analysis revealed that the total average retina pigment epithelium thickness was statistically significantly thinner in the nonexudative AMD group compared with the exudative AMD and control groups (P = 0.001 and P = 0.040, respectively). The total average outer nuclear layer (ONL) thicknesses of nonexudative and exudative AMD cases were reduced compared to control group; however, the decrement was statistically significant only in the nonexudative AMD group (P = 0.009). In the correlation analysis of BDNF levels with retinal layer thicknesses, statistically significant correlations exist between BDNF levels of AH with ONL thicknesses in cases of AMD and with retina pigment epithelium thicknesses in the nonexudative AMD group. Conclusions BDNF concentrations in AH decreased in the AMD group and this decrease correlates with outer retinal layer thicknesses. Low BDNF levels detected in the AMD group may be insufficient to protect the photoreceptors, resulting in thinning of ONL.
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Affiliation(s)
| | | | - Canan Demirtas
- Department of Medical Biochemistry, Gazi University, Ankara, Turkey
| | - Kemal Tekin
- Department of Ophthalmology, Kars State Hospital, Kars, Turkey
| | - Sibel Doguizi
- Ankara Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
| | - Serdar Bayraktar
- Ankara Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
| | - Pelin Yilmazbas
- Ankara Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
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63
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Loss of Shp2 Rescues BDNF/TrkB Signaling and Contributes to Improved Retinal Ganglion Cell Neuroprotection. Mol Ther 2018; 27:424-441. [PMID: 30341011 DOI: 10.1016/j.ymthe.2018.09.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 09/18/2018] [Accepted: 09/27/2018] [Indexed: 12/21/2022] Open
Abstract
Glaucoma is characterized by the loss of retinal ganglion cells (RGC), and accordingly the preservation of RGCs and their axons has recently attracted significant attention to improve therapeutic outcomes in the disease. Here, we report that Src homology region 2-containing protein tyrosine phosphatase 2 (Shp2) undergoes activation in the RGCs, in animal model of glaucoma as well as in the human glaucoma tissues and that Shp2 dephosphorylates tropomyosin receptor kinase B (TrkB) receptor, leading to reduced BDNF/TrkB neuroprotective survival signaling. This was elucidated by specifically modulating Shp2 expression in the RGCs in vivo, using adeno-associated virus serotype 2 (AAV2) constructs. Shp2 upregulation promoted endoplasmic reticulum (ER) stress and apoptosis, along with functional and structural deficits in the inner retina. In contrast, loss of Shp2 decelerated the loss of RGCs, preserved their function, and suppressed ER stress and apoptosis in glaucoma. This report constitutes the first identification of Shp2-mediated TrkB regulatory mechanisms in the RGCs that can become a potential therapeutic target in both glaucoma and other neurodegenerative disorders.
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64
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Osborne A, Khatib TZ, Songra L, Barber AC, Hall K, Kong GYX, Widdowson PS, Martin KR. Neuroprotection of retinal ganglion cells by a novel gene therapy construct that achieves sustained enhancement of brain-derived neurotrophic factor/tropomyosin-related kinase receptor-B signaling. Cell Death Dis 2018; 9:1007. [PMID: 30258047 PMCID: PMC6158290 DOI: 10.1038/s41419-018-1041-8] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 09/04/2018] [Accepted: 09/07/2018] [Indexed: 01/17/2023]
Abstract
Previous studies have demonstrated that intravitreal delivery of brain-derived neurotrophic factor (BDNF) by injection of recombinant protein or by gene therapy can alleviate retinal ganglion cell (RGC) loss after optic nerve injury. BDNF gene therapy can improve RGC survival in experimental models of glaucoma, the leading cause of irreversible blindness worldwide. However, the therapeutic efficacy of BDNF supplementation alone is time limited at least in part due to BDNF receptor downregulation. Tropomyosin-related receptor kinase-B (TrkB) downregulation has been reported in many neurological diseases including glaucoma, potentially limiting the effect of sustained or repeated BDNF delivery. Here, we characterize a novel adeno-associated virus (AAV) gene therapy (AAV2 TrkB-2A-mBDNF) that not only increases BDNF production but also improves long-term neuroprotective signaling by increasing expression of the BDNF receptor (TrkB) within the inner retina. This approach leads to significant and sustained elevation of survival signaling pathways ERK and AKT within RGCs over 6 months and avoids the receptor downregulation which we observe with treatment with AAV2 BDNF alone. We validate the neuroprotective efficacy of AAV2 TrkB-2A-mBDNF in a mouse model of optic nerve injury, where it outperforms conventional AAV2 BDNF or AAV2 TrkB therapy, before showing powerful proof of concept neuroprotection of RGCs and axons in a rat model of chronic intraocular pressure (IOP) elevation. We also show that there are no adverse effects of the vector on retinal structure or function as assessed by histology and electroretinography in young or aged animals. Further studies are underway to explore the potential of this vector as a candidate for progression into clinical studies to protect RGCs in patients with glaucoma and progressive visual loss despite conventional IOP-lowering treatment.
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Affiliation(s)
- Andrew Osborne
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Quethera Ltd, Babraham Research Campus, Cambridge, UK
| | - Tasneem Z Khatib
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,Eye Department, Addenbrooke's Hospital, Cambridge, UK
| | - Lalana Songra
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Amanda C Barber
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Katie Hall
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - George Y X Kong
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.,University of Melbourne, Melbourne, Australia
| | | | - Keith R Martin
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK. .,Quethera Ltd, Babraham Research Campus, Cambridge, UK. .,Eye Department, Addenbrooke's Hospital, Cambridge, UK. .,Cambridge NIHR Biomedical Research Centre, Cambridge, UK. .,Wellcome Trust-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK.
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65
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Eriksen AZ, Eliasen R, Oswald J, Kempen PJ, Melander F, Andresen TL, Young M, Baranov P, Urquhart AJ. Multifarious Biologic Loaded Liposomes that Stimulate the Mammalian Target of Rapamycin Signaling Pathway Show Retina Neuroprotection after Retina Damage. ACS NANO 2018; 12:7497-7508. [PMID: 30004669 PMCID: PMC6117751 DOI: 10.1021/acsnano.8b00596] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A common event in optic neuropathies is the loss of axons and death of retinal ganglion cells (RGCs) resulting in irreversible blindness. Mammalian target of rapamycin (mTOR) signaling pathway agonists have been shown to foster axon regeneration and RGC survival in animal models of optic nerve damage. However, many challenges remain in developing therapies that exploit cell growth and tissue remodeling including (i) activating/inhibiting cell pathways synergistically, (ii) avoiding tumorigenesis, and (iii) ensuring appropriate physiological tissue function. These challenges are further exacerbated by the need to overcome ocular physiological barriers and clearance mechanisms. Here we present liposomes loaded with multiple mTOR pathway stimulating biologics designed to enhance neuroprotection after retina damage. Liposomes were loaded with ciliary neurotrophic factor, insulin-like growth factor 1, a lipopeptide N-fragment osteopontin mimic, and lipopeptide phosphatase tension homologue inhibitors for either the ATP domain or the c-terminal tail. In a mouse model of N-methyl-d-aspartic acid induced RGC death, a single intravitreal administration of liposomes reduced both RGC death and loss of retina electrophysiological function. Furthermore, combining liposomes with transplantation of induced pluripotent stem cell derived RGCs led to an improved electrophysiological outcome in mice. The results presented here show that liposomes carrying multiple signaling pathway modulators can facilitate neuroprotection and transplant electrophysiological outcome.
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Affiliation(s)
- Anne Z. Eriksen
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Rasmus Eliasen
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Julia Oswald
- Schepens
Eye Research Institute, Massachusetts Eye and Ear, 20 Staniford Street, Boston, Massachusetts 02114, United States
| | - Paul J. Kempen
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Fredrik Melander
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Thomas L. Andresen
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Michael Young
- Schepens
Eye Research Institute, Massachusetts Eye and Ear, 20 Staniford Street, Boston, Massachusetts 02114, United States
| | - Petr Baranov
- Schepens
Eye Research Institute, Massachusetts Eye and Ear, 20 Staniford Street, Boston, Massachusetts 02114, United States
| | - Andrew J. Urquhart
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
- E-mail:
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66
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Shim MS, Kim KY, Noh M, Ko JY, Ahn S, An MA, Iwata T, Perkins GA, Weinreb RN, Ju WK. Optineurin E50K triggers BDNF deficiency-mediated mitochondrial dysfunction in retinal photoreceptor cell line. Biochem Biophys Res Commun 2018; 503:2690-2697. [PMID: 30100066 DOI: 10.1016/j.bbrc.2018.08.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 08/03/2018] [Indexed: 10/28/2022]
Abstract
Optineurin (OPTN) mutations are linked to glaucoma pathology and E50K mutation shows massive cell death in photoreceptor cells and retinal ganglion cells. However, little is known about E50K-mediated mitochondrial dysfunction in photoreceptor cell degeneration. We here show that overexpression of E50K expression triggered BDNF deficiency, leading to Bax activation in RGC-5 cells. BDNF deficiency induced mitochondrial dysfunction by decreasing mitochondrial maximal respiration and reducing intracellular ATP level in RGC-5 cells. However, BDNF deficiency did not alter mitochondrial dynamics. Also, BDNF deficiency resulted in LC3-mediated mitophagosome formation in RGC-5 cells. These results strongly suggest that E50K-mediated BDNF deficiency plays a critical role in compromised mitochondrial function in glaucomatous photoreceptor cell degeneration.
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Affiliation(s)
- Myoung Sup Shim
- Hamilton Glaucoma Center, Shiley Eye Institute and Department of Ophthalmology, University of California San Diego, La Jolla, CA, 92039, USA
| | - Keun-Young Kim
- National Center for Microscopy and Imaging Research and Department of Neuroscience, University of California San Diego, La Jolla, CA, 92093, USA
| | - Mark Noh
- Hamilton Glaucoma Center, Shiley Eye Institute and Department of Ophthalmology, University of California San Diego, La Jolla, CA, 92039, USA
| | - Ji Yoon Ko
- Hamilton Glaucoma Center, Shiley Eye Institute and Department of Ophthalmology, University of California San Diego, La Jolla, CA, 92039, USA
| | - Sangphil Ahn
- Hamilton Glaucoma Center, Shiley Eye Institute and Department of Ophthalmology, University of California San Diego, La Jolla, CA, 92039, USA
| | - Michelle A An
- Hamilton Glaucoma Center, Shiley Eye Institute and Department of Ophthalmology, University of California San Diego, La Jolla, CA, 92039, USA
| | - Takeshi Iwata
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Guy A Perkins
- National Center for Microscopy and Imaging Research and Department of Neuroscience, University of California San Diego, La Jolla, CA, 92093, USA
| | - Robert N Weinreb
- Hamilton Glaucoma Center, Shiley Eye Institute and Department of Ophthalmology, University of California San Diego, La Jolla, CA, 92039, USA
| | - Won-Kyu Ju
- Hamilton Glaucoma Center, Shiley Eye Institute and Department of Ophthalmology, University of California San Diego, La Jolla, CA, 92039, USA.
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67
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Chen DW, Foldvari M. Retinal Multipotent Stem-Cell Derived “MiEye” Spheroid 3D Culture Model for Preclinical Screening of Non-viral Gene Delivery Systems. PRECISION NANOMEDICINE 2018. [DOI: 10.29016/180711.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Non-viral retinal gene therapy is a promising therapeutic approach towards the management of retinal degenerative diseases especially glaucoma. Current methods of in vitro preclinical screening of candidate nanoparticle systems in monolayer cell cultures are not reliable in predicting in vivo performance. In this paper, we describe the development of a multipotent stem-cell derived three-dimensional “mini-retina” culture model (MiEye) that aims to simulate an in vivo clinical model for more reliable gene delivery system screening. Through the utilization of multiplex gene expression profiling, we have shown that retinal stem cells can be differentiated in 3D culture to generate retinal neurospheres comprising of multiple retinal cell types. The 3D cell culture model combined with confocal microscopy imaging and fluorescence profiling techniques is a powerful tool as a retinal gene and drug delivery screening model.
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68
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Guymer C, Wood JPM, Chidlow G, Casson RJ. Neuroprotection in glaucoma: recent advances and clinical translation. Clin Exp Ophthalmol 2018; 47:88-105. [DOI: 10.1111/ceo.13336] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 05/21/2018] [Accepted: 06/06/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Chelsea Guymer
- Ophthalmic Research Laboratory, South Australian Institute of Ophthalmology; University of Adelaide; Adelaide South Australia Australia
| | - John PM Wood
- Ophthalmic Research Laboratory, South Australian Institute of Ophthalmology; University of Adelaide; Adelaide South Australia Australia
| | - Glyn Chidlow
- Ophthalmic Research Laboratory, South Australian Institute of Ophthalmology; University of Adelaide; Adelaide South Australia Australia
| | - Robert J Casson
- Ophthalmic Research Laboratory, South Australian Institute of Ophthalmology; University of Adelaide; Adelaide South Australia Australia
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69
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Shen T, You Y, Joseph C, Mirzaei M, Klistorner A, Graham SL, Gupta V. BDNF Polymorphism: A Review of Its Diagnostic and Clinical Relevance in Neurodegenerative Disorders. Aging Dis 2018; 9:523-536. [PMID: 29896439 PMCID: PMC5988606 DOI: 10.14336/ad.2017.0717] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 07/17/2017] [Indexed: 12/17/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) has a unique role in the neuronal development, differentiation, and survival in the developing and adult nervous system. A common single-nucleotide polymorphism in the pro-region of the human BDNF gene, resulting in a valine to methionine substitution (Val66Met), has been associated with the susceptibility, incidence, and clinical features of several neurodegenerative disorders. Much research has been dedicated to evaluating the effects of polymorphism in the past decade, and functional effects of this genetic variation. A better understanding of how this naturally occurring polymorphism associates with or influences physiology, anatomy, and cognition in both healthy and diseased adults in neurodegenerative conditions will help understand neurochemical mechanisms and definable clinical outcomes in humans. Here we review the role and relevance of the BDNF Val66Met polymorphism in neurodegenerative diseases, with particular emphasis on glaucoma, multiple sclerosis (MS), Alzheimer’s disease (AD) and Parkinson’s disease (PD). Several controversies and unresolved issues, including small effect sizes, possible ethnicity, gender, and age effects of the BDNF Val66Met are also discussed with respect to future research.
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Affiliation(s)
- Ting Shen
- 1Faculty of Medicine and Health Sciences, Macquarie University, Australia
| | - Yuyi You
- 2Save Sight Institute, Sydney University, Sydney, Australia
| | - Chitra Joseph
- 1Faculty of Medicine and Health Sciences, Macquarie University, Australia
| | - Mehdi Mirzaei
- 3Faculty of Science and Engineering, Macquarie University, Australia
| | - Alexander Klistorner
- 1Faculty of Medicine and Health Sciences, Macquarie University, Australia.,2Save Sight Institute, Sydney University, Sydney, Australia
| | - Stuart L Graham
- 1Faculty of Medicine and Health Sciences, Macquarie University, Australia.,2Save Sight Institute, Sydney University, Sydney, Australia
| | - Vivek Gupta
- 1Faculty of Medicine and Health Sciences, Macquarie University, Australia
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70
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Progress in Gene Therapy to Prevent Retinal Ganglion Cell Loss in Glaucoma and Leber's Hereditary Optic Neuropathy. Neural Plast 2018; 2018:7108948. [PMID: 29853847 PMCID: PMC5954906 DOI: 10.1155/2018/7108948] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 04/04/2018] [Indexed: 12/24/2022] Open
Abstract
The eye is at the forefront of the application of gene therapy techniques to medicine. In the United States, a gene therapy treatment for Leber's congenital amaurosis, a rare inherited retinal disease, recently became the first gene therapy to be approved by the FDA for the treatment of disease caused by mutations in a specific gene. Phase III clinical trials of gene therapy for other single-gene defect diseases of the retina and optic nerve are also currently underway. However, for optic nerve diseases not caused by single-gene defects, gene therapy strategies are likely to focus on slowing or preventing neuronal death through the expression of neuroprotective agents. In addition to these strategies, there has also been recent interest in the potential use of precise genome editing techniques to treat ocular disease. This review focuses on recent developments in gene therapy techniques for the treatment of glaucoma and Leber's hereditary optic neuropathy (LHON). We discuss recent successes in clinical trials for the treatment of LHON using gene supplementation therapy, promising neuroprotective strategies that have been employed in animal models of glaucoma and the potential use of genome editing techniques in treating optic nerve disease.
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71
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Dvoriantchikova G, Pronin A, Kurtenbach S, Toychiev A, Chou TH, Yee CW, Prindeville B, Tayou J, Porciatti V, Sagdullaev BT, Slepak VZ, Shestopalov VI. Pannexin 1 sustains the electrophysiological responsiveness of retinal ganglion cells. Sci Rep 2018; 8:5797. [PMID: 29643381 PMCID: PMC5895610 DOI: 10.1038/s41598-018-23894-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 03/20/2018] [Indexed: 12/16/2022] Open
Abstract
Pannexin 1 (Panx1) forms ATP-permeable membrane channels that play a key role in purinergic signaling in the nervous system in both normal and pathological conditions. In the retina, particularly high levels of Panx1 are found in retinal ganglion cells (RGCs), but the normal physiological function in these cells remains unclear. In this study, we used patch clamp recordings in the intact inner retina to show that evoked currents characteristic of Panx1 channel activity were detected only in RGCs, particularly in the OFF-type cells. The analysis of pattern electroretinogram (PERG) recordings indicated that Panx1 contributes to the electrical output of the retina. Consistently, PERG amplitudes were significantly impaired in the eyes with targeted ablation of the Panx1 gene in RGCs. Under ocular hypertension and ischemic conditions, however, high Panx1 activity permeated cell membranes and facilitated the selective loss of RGCs or stably transfected Neuro2A cells. Our results show that high expression of the Panx1 channel in RGCs is essential for visual function in the inner retina but makes these cells highly sensitive to mechanical and ischemic stresses. These findings are relevant to the pathophysiology of retinal disorders induced by increased intraocular pressure, such as glaucoma.
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Affiliation(s)
- Galina Dvoriantchikova
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, 900 NW 10 Ave., Miami, FL, 33136, USA
| | - Alexey Pronin
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, 1600 NW 10th Ave., Miami, FL, 33136, USA
| | - Sarah Kurtenbach
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, 900 NW 10 Ave., Miami, FL, 33136, USA
| | - Abduqodir Toychiev
- Department of Ophthalmology, Weill Cornell Medical College, 156 William St., New York, NY, 10038, USA
| | - Tsung-Han Chou
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, 900 NW 10 Ave., Miami, FL, 33136, USA
| | - Christopher W Yee
- Winifred Masterson Burke Medical Research Institute, New York, 785 Mamaroneck Ave., White Plains, NY, 10605, USA
| | - Breanne Prindeville
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, 900 NW 10 Ave., Miami, FL, 33136, USA
| | - Junior Tayou
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, 1600 NW 10th Ave., Miami, FL, 33136, USA
| | - Vittorio Porciatti
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, 900 NW 10 Ave., Miami, FL, 33136, USA
| | - Botir T Sagdullaev
- Department of Ophthalmology, Weill Cornell Medical College, 156 William St., New York, NY, 10038, USA
- Winifred Masterson Burke Medical Research Institute, New York, 785 Mamaroneck Ave., White Plains, NY, 10605, USA
| | - Vladlen Z Slepak
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, 1600 NW 10th Ave., Miami, FL, 33136, USA
| | - Valery I Shestopalov
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, 900 NW 10 Ave., Miami, FL, 33136, USA.
- Department of Cell Biology, University of Miami Miller School of Medicine, 1600 NW 10th Ave., Miami, FL, 33136, USA.
- Vavilov Institute for General Genetics, Gubkina Str. 3, Russian Academy of Sciences, Moscow, Russia.
- Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia.
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72
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Physical activity, visual impairment, and eye disease. Eye (Lond) 2018; 32:1296-1303. [PMID: 29610523 DOI: 10.1038/s41433-018-0081-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 02/11/2018] [Accepted: 02/21/2018] [Indexed: 12/26/2022] Open
Abstract
Numerous studies have demonstrated physical activity is a strong factor in overall health and well-being, and a growing body of literature, reviewed herein, suggests that several eye conditions, including glaucoma, age-related macular degeneration, and diabetic retinopathy, are associated with lower activity levels. Likewise, physical activity levels are lower in persons with worse vision. Research in this area has utilized both self-reported physical activity measures as well as objective measures of activity (i.e., accelerometers), each of which have their own strengths and limitations. Putative mechanisms explaining the association of various eye conditions with physical activity are discussed. It is possible that activity restriction occurs as a downstream consequence of eye disease/visual impairment, that activity restriction causes eye disease/visual impairment, or that causality is bidirectional; evidence supporting each of these theories is put forth. An improved understanding of the relationship between physical activity and eye disease will highlight potential secondary health risks resulting from eye disease, and can help determine whether activity might serve as a readily available preventative measure to prevent specific eye conditions.
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73
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Mysona BA, Zhao J, Smith S, Bollinger KE. Relationship between Sigma-1 receptor and BDNF in the visual system. Exp Eye Res 2018; 167:25-30. [PMID: 29031856 PMCID: PMC5757370 DOI: 10.1016/j.exer.2017.10.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 10/10/2017] [Accepted: 10/11/2017] [Indexed: 12/27/2022]
Abstract
Glaucoma is an incurable optic neuropathy characterized by dysfunction and death of retinal ganglion cells (RGCs). Brain derived neurotrophic factor (BDNF) is an essential neurotrophin that supports RGC function and survival. Despite BDNF's importance, our knowledge of molecular mechanisms that modulate BDNF processing and secretion is incomplete. Sigma-1 receptor (S1R) is associated with increased BDNF in hippocampus and with BDNF secretion by brain-derived astrocytes and neuronal cell lines. Much less is known about the relationship between S1R and BDNF in the visual system. Here, we examine how S1R activation and deletion alter expression of mature BDNF (mBDNF) and proBDNF in retina and cultured optic nerve head (ONH) astrocytes. For S1R activation, the S1R agonist (+)-pentazocine (PTZ, 0.5 mg/kg) was administered by intraperitoneal injection to C57BL/6J mice, 3 times per week, for 5 weeks. Expression of proBDNF and mBDNF was also examined in S1R knockout and age-matched C57BL/6J mice. In vitro, cultured ONH astrocytes were treated with 3 μM PTZ for 24 h followed by collection of media and ONH astrocyte lysates. Results showed that treatment with (+)-PTZ increased mBDNF protein in both retina and hippocampus. In contrast, S1R deletion was associated with retinal mBDNF deficits. In ONH astrocytes S1R agonist (+)-PTZ significantly increased levels of secreted BDNF and proBDNF in cell lysates. These findings support a role for S1R in the modulation of BDNF levels within the retina and optic nerve head. Treatment with S1R agonists might provide benefit in diseases such as glaucoma by increasing BDNF levels from endogenous sources.
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Affiliation(s)
- Barbara A Mysona
- James and Jean Culver Vision Discovery Institute, Augusta, GA, 30912, United States; Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, United States; Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, United States
| | - Jing Zhao
- James and Jean Culver Vision Discovery Institute, Augusta, GA, 30912, United States; Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, United States; Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, United States
| | - Sylvia Smith
- James and Jean Culver Vision Discovery Institute, Augusta, GA, 30912, United States; Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, United States; Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, United States
| | - Kathryn E Bollinger
- James and Jean Culver Vision Discovery Institute, Augusta, GA, 30912, United States; Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA, 30912, United States; Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, 30912, United States.
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74
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Sharif NA. iDrugs and iDevices Discovery Research: Preclinical Assays, Techniques, and Animal Model Studies for Ocular Hypotensives and Neuroprotectants. J Ocul Pharmacol Ther 2018; 34:7-39. [PMID: 29323613 DOI: 10.1089/jop.2017.0125] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Discovery ophthalmic research is centered around delineating the molecular and cellular basis of ocular diseases and finding and exploiting molecular and genetic pathways associated with them. From such studies it is possible to determine suitable intervention points to address the disease process and hopefully to discover therapeutics to treat them. An investigational new drug (IND) filing for a new small-molecule drug, peptide, antibody, genetic treatment, or a device with global health authorities requires a number of preclinical studies to provide necessary safety and efficacy data. Specific regulatory elements needed for such IND-enabling studies are beyond the scope of this article. However, to enhance the overall data packages for such entities and permit high-quality foundation-building publications for medical affairs, additional research and development studies are always desirable. This review aims to provide examples of some target localization/verification, ocular drug discovery processes, and mechanistic and portfolio-enhancing exploratory investigations for candidate drugs and devices for the treatment of ocular hypertension and glaucomatous optic neuropathy (neurodegeneration of retinal ganglion cells and their axons). Examples of compound screening assays, use of various technologies and techniques, deployment of animal models, and data obtained from such studies are also presented.
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Affiliation(s)
- Najam A Sharif
- 1 Global Alliances & External Research , Santen Incorporated, Emeryville, California.,2 Department of Pharmaceutical Sciences, Texas Southern University , Houston, Texas.,3 Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center , Fort Worth, Texas
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75
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Chitranshi N, Dheer Y, Abbasi M, You Y, Graham SL, Gupta V. Glaucoma Pathogenesis and Neurotrophins: Focus on the Molecular and Genetic Basis for Therapeutic Prospects. Curr Neuropharmacol 2018; 16:1018-1035. [PMID: 29676228 PMCID: PMC6120108 DOI: 10.2174/1570159x16666180419121247] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 04/10/2018] [Accepted: 04/18/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Retinal ganglion cell (RGC) degeneration is a major feature of glaucoma pathology. Neuroprotective approaches that delay or halt the progression of RGC loss are needed to prevent vision loss which can occur even after conventional medical or surgical treatments to lower intraocular pressure. OBJECTIVE The aim of this review was to examine the progress in genetics and cellular mechanisms associated with endoplasmic reticulum (ER) stress, RGC dysfunction and cell death pathways in glaucoma. MATERIALS AND METHODS Here, we review the involvement of neurotrophins like brain derived neurotrophic factor (BDNF) and its high affinity receptor tropomyosin receptor kinase (TrkB) in glaucoma. The role of ER stress markers in human and animal retinas in health and disease conditions is also discussed. Further, we analysed the literature highlighting genetic linkage in the context of primary open angle glaucoma and suggested mechanistic insights into potential therapeutic options relevant to glaucoma management. RESULTS The literature review of the neurobiology underlying neurotrophin pathways, ER stress and gene associations provide critical insights into association of RGCs death in glaucoma. Alteration in signalling pathway is associated with increased risk of misfolded protein aggregation in ER promoting RGC apoptosis. Several genes that are linked with neurotrophin signalling pathways have been reported to be associated with glaucoma pathology. CONCLUSION Understanding genetic heterogeneity and involvement of neurotrophin biology in glaucoma could help to understand the complex pathophysiology of glaucoma. Identification of novel molecular targets will be critical for drug development and provide neuroprotection to the RGCs and optic nerve.
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Affiliation(s)
- Nitin Chitranshi
- Address correspondence to this author at the Faculty of Medicine and Health Sciences, 75, Talavera Road, Macquarie University, Sydney, NSW 2109, Australia; Tel: +61-298502760; E-mail:
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76
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Nickells RW, Schmitt HM, Maes ME, Schlamp CL. AAV2-Mediated Transduction of the Mouse Retina After Optic Nerve Injury. Invest Ophthalmol Vis Sci 2017; 58:6091-6104. [PMID: 29204649 PMCID: PMC5716181 DOI: 10.1167/iovs.17-22634] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Purpose Gene therapy of retinal ganglion cells (RGCs) has promise as a powerful therapeutic for the rescue and regeneration of these cells after optic nerve damage. However, early after damage, RGCs undergo atrophic changes, including gene silencing. It is not known if these changes will deleteriously affect transduction and transgene expression, or if the therapeutic protein can influence reactivation of the endogenous genome. Methods Double-transgenic mice carrying a Rosa26-(LoxP)-tdTomato reporter, and a mutant allele for the proapoptotic Bax gene were reared. The Bax mutant blocks apoptosis, but RGCs still exhibit nuclear atrophy and gene silencing. At times ranging from 1 hour to 4 weeks after optic nerve crush (ONC), eyes received an intravitreal injection of AAV2 virus carrying the Cre recombinase. Successful transduction was monitored by expression of the tdTomato reporter. Immunostaining was used to localize tdTomato expression in select cell types. Results Successful transduction of RGCs was achieved at all time points after ONC using AAV2 expressing Cre from the phosphoglycerate kinase (Pgk) promoter, but not the CMV promoter. ONC promoted an increase in the transduction of cell types in the inner nuclear layer, including Müller cells and rod bipolar neurons. There was minimal evidence of transduction of amacrine cells and astrocytes in the inner retina or optic nerve. Conclusions Damaged RGCs can be transduced and at least some endogenous genes can be subsequently activated. Optic nerve damage may change retinal architecture to allow greater penetration of an AAV2 virus to transduce several additional cell types in the inner nuclear layer.
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Affiliation(s)
- Robert W Nickells
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - Heather M Schmitt
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States.,Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - Margaret E Maes
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States.,Institute of Science and Technology Austria, Klosterneurberg, Austria
| | - Cassandra L Schlamp
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States
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77
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Generative mathematical modelling to demonstrate virtual simulations of neovascular age related macular degeneration. PLoS One 2017; 12:e0189053. [PMID: 29211782 PMCID: PMC5718607 DOI: 10.1371/journal.pone.0189053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 11/17/2017] [Indexed: 11/26/2022] Open
Abstract
Purpose To develop a generative mathematical model of wet age-related macular degeneration (AMD) and model the impact of injections of anti-vascular endothelial growth factor to virtual patients with the condition. Methods We isolated key pathophysiological components of macular degeneration in terms of macular edema development and response to anti-vascular endothelial growth factor (VEGF) agents. We developed mathematical models for each of these components using constants determined from published biological experimentation. Consequently, we combined the mathematical models of the separate components to arrive at an end-to-end model of the evolution of macular edema size and its response to treatment. Results We present a series of simulations based upon our idealised model. Initially, we demonstrate the theoretical change in macular edema height in wet macular degeneration over time without and with anti-VEGF interventions. In our final simulation, we demonstrate the powerful possibilities of virtual clinical trials by simulating a virtual model of a landmark study using our existing mathematical AMD model. Conclusions Using our mathematical modelling based upon known pathological and pharmacological processes we have been able to model the effect of intravitreal injection of an anti-VEGF agent on macular edema from age related macular degeneration. We were subsequently able to mathematically simulate a major clinical trial with results that mirror many key features of the clinical established study. We anticipate that the generative model presented here can evolve to be a useful supportive tool in the challenge to deliver optimal therapy for patients with wet macular degeneration.
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78
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Three-Dimensional Co-Culture Bioassay for Screening of Retinal Gene Delivery Systems. Methods Mol Biol 2017. [PMID: 29188507 DOI: 10.1007/978-1-4939-7522-8_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Herein we describe a three-dimensional co-culture bioassay protocol designed to assess the therapeutic potential of the proteins expressed from gene delivery transfected cells through the evaluation of expressed protein bioavailability and bioactivity. Using a combination of enzyme-linked immunosorbent assay (ELISA) and immunofluorescent-based neurite length profiling methodologies, the bioavailability of the secreted therapeutic protein in the medium can be quantitated, and the bioactivity of the secreted therapeutic protein can also be evaluated through neurite length profiling, respectively. The versatility and rationale of this bioassay could serve as a useful screening tool in the development of retinal gene delivery systems.
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Shpak AA, Guekht AB, Druzhkova TA, Kozlova KI, Gulyaeva NV. Brain-Derived Neurotrophic Factor in Patients with Primary Open-Angle Glaucoma and Age-related Cataract. Curr Eye Res 2017; 43:224-231. [DOI: 10.1080/02713683.2017.1396617] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Alexander A Shpak
- Department for Clinical and Functional Diagnostics, The S. Fyodorov Eye Microsurgery Federal State Institution, Moscow, Russian Federation
| | - Alla B Guekht
- Moscow Research and Clinical Center for Neuropsychiatry of the Healthcare Department of Moscow, Moscow, Russian Federation
| | - Tatiana A Druzhkova
- Moscow Research and Clinical Center for Neuropsychiatry of the Healthcare Department of Moscow, Moscow, Russian Federation
| | - Ksenia I Kozlova
- Department for Clinical and Functional Diagnostics, The S. Fyodorov Eye Microsurgery Federal State Institution, Moscow, Russian Federation
| | - Natalia V Gulyaeva
- Department of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Moscow, Russian Federation
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80
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Chen DW, Foldvari M. In vitro bioassay model for screening non-viral neurotrophic factor gene delivery systems for glaucoma treatment. Drug Deliv Transl Res 2017; 6:676-685. [PMID: 27549107 DOI: 10.1007/s13346-016-0324-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The feasibility of a two-layer contact-independent 3D neuronal co-culture model to test the bioactivity of brain-derived neurotrophic factor (BDNF), produced by non-virally transfected A7 astrocytes (trA7), on neurite growth in a second cell population of SH-SY5Y (CRL-2266) neuroblastoma cells with (oxSH-SY5Y) or without oxidative damage (SH-SY5Y) was evaluated. Transfection of A7 astrocytes was carried out with BDNF-encoding plasmid using K2® nanoparticle gene delivery system (K2-NPs). The physicochemical characteristics of K2-NPs, transfection efficiency, and BDNF production were evaluated using dynamic light scattering, flow cytometry, and enzyme-linked immunosorbent assay (ELISA), respectively. Neurite counts and length measurements were performed after anti-neuron-specific β-III tubulin antibody immunostaining using confocal laser scanning microscopy. Transfection efficiency of A7 astrocytes by K2-NPs (diameter 83.9 ± 0.4 nm, zeta potential +57.3 ± 2.8 mV) was 39.5 ± 4.6 % with cell viability of 73 ± 2 %. BDNF levels produced were 3750.8 ± 251.1, 9052.6 ± 1391.2, and 10,367.1 ± 390.8 pg/mL at 24, 48, and 72 h, respectively. The increased number of neurites with higher neurite lengths confirmed the bioactivity of BDNF secreted from the transfected A7 astrocytes over 72 h. Neurite count comparisons showed that both trA7/oxSH-SY5Y and trA7/SH-SY5Y consistently produced higher neurite counts compared to A7/oxSH-SY5Y and oxSH-SY5Y only experimental conditions. The results of this study demonstrate that neurite outgrowth quantitation in astrocyte-SH-SY5Y cell co-culture is a suitable bioassay model for evaluating non-viral gene delivery systems. Furthermore, it also demonstrates a proof-of-concept for nanoparticle-based neurotrophic factor gene delivery to astrocytes and stimulation of neurite outgrowth.
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Affiliation(s)
- Ding Wen Chen
- School of Pharmacy, Waterloo Institute of Nanotechnology and Center for Bioengineering and Biotechnology, University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - Marianna Foldvari
- School of Pharmacy, Waterloo Institute of Nanotechnology and Center for Bioengineering and Biotechnology, University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada.
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81
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Takahama S, Adetunji MO, Zhao T, Chen S, Li W, Tomarev SI. Retinal Astrocytes and GABAergic Wide-Field Amacrine Cells Express PDGFRα: Connection to Retinal Ganglion Cell Neuroprotection by PDGF-AA. Invest Ophthalmol Vis Sci 2017; 58:4703-4711. [PMID: 28910446 PMCID: PMC5606213 DOI: 10.1167/iovs.21783] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Purpose Our previous experiments demonstrated that intravitreal injection of platelet-derived growth factor-AA (PDGF-AA) provides retinal ganglion cell (RGC) neuroprotection in a rodent model of glaucoma. Here we used PDGFRα-enhanced green fluorescent protein (EGFP) mice to identify retinal cells that may be essential for RGC protection by PDGF-AA. Methods PDGFRα-EGFP mice expressing nuclear-targeted EGFP under the control of the PDGFRα promoter were used. Localization of PDGFRα in the neural retina was investigated by confocal imaging of EGFP fluorescence and immunofluorescent labeling with a panel of antibodies recognizing different retinal cell types. Primary cultures of mouse RGCs were produced by immunopanning. Neurobiotin injection of amacrine cells in a flat-mounted retina was used for the identification of EGFP-positive amacrine cells in the inner nuclear layer. Results In the mouse neural retina, PDGFRα was preferentially localized in the ganglion cell and inner nuclear layers. Immunostaining of the retina demonstrated that astrocytes in the ganglion cell layer and a subpopulation of amacrine cells in the inner nuclear layer express PDGFRα, whereas RGCs (in vivo or in vitro) did not. PDGFRα-positive amacrine cells are likely to be Type 45 gamma-aminobutyric acidergic (GABAergic) wide-field amacrine cells. Conclusions These data indicate that the neuroprotective effect of PDGF-AA in a rodent model of glaucoma could be mediated by astrocytes and/or a subpopulation of amacrine cells. We suggest that after intravitreal injection of PDGF-AA, these cells secrete factors protecting RGCs.
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Affiliation(s)
- Shokichi Takahama
- Section on Retinal Ganglion Cell Biology, Laboratory of Retinal Cell and Molecular Biology, National Institutes of Health, Bethesda, Maryland, United States
| | - Modupe O Adetunji
- Section on Retinal Ganglion Cell Biology, Laboratory of Retinal Cell and Molecular Biology, National Institutes of Health, Bethesda, Maryland, United States
| | - Tantai Zhao
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Shan Chen
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Wei Li
- Retinal Neurophysiology Section, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Stanislav I Tomarev
- Section on Retinal Ganglion Cell Biology, Laboratory of Retinal Cell and Molecular Biology, National Institutes of Health, Bethesda, Maryland, United States
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82
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He S, Stankowska DL, Ellis DZ, Krishnamoorthy RR, Yorio T. Targets of Neuroprotection in Glaucoma. J Ocul Pharmacol Ther 2017; 34:85-106. [PMID: 28820649 DOI: 10.1089/jop.2017.0041] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Progressive neurodegeneration of the optic nerve and the loss of retinal ganglion cells is a hallmark of glaucoma, the leading cause of irreversible blindness worldwide, with primary open-angle glaucoma (POAG) being the most frequent form of glaucoma in the Western world. While some genetic mutations have been identified for some glaucomas, those associated with POAG are limited and for most POAG patients, the etiology is still unclear. Unfortunately, treatment of this neurodegenerative disease and other retinal degenerative diseases is lacking. For POAG, most of the treatments focus on reducing aqueous humor formation, enhancing uveoscleral or conventional outflow, or lowering intraocular pressure through surgical means. These efforts, in some cases, do not always lead to a prevention of vision loss and therefore other strategies are needed to reduce or reverse the progressive neurodegeneration. In this review, we will highlight some of the ocular pharmacological approaches that are being tested to reduce neurodegeneration and provide some form of neuroprotection.
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Affiliation(s)
- Shaoqing He
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
| | - Dorota L Stankowska
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
| | - Dorette Z Ellis
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
| | - Raghu R Krishnamoorthy
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
| | - Thomas Yorio
- North Texas Eye Research Institute, University of North Texas Health Science Center , Fort Worth, Texas
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83
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Feng L, Chen H, Yi J, Troy JB, Zhang HF, Liu X. Long-Term Protection of Retinal Ganglion Cells and Visual Function by Brain-Derived Neurotrophic Factor in Mice With Ocular Hypertension. Invest Ophthalmol Vis Sci 2017; 57:3793-802. [PMID: 27421068 PMCID: PMC4961002 DOI: 10.1167/iovs.16-19825] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Purpose Glaucoma, frequently associated with elevated intraocular pressure (IOP), is characterized by progressive retinal ganglion cell (RGC) death and vision loss. Brain-derived neurotrophic factor (BDNF) has been studied as a candidate for neuroprotection in rodent models of experimental glaucoma, yet it remains to be determined whether BDNF exerts long-term protection for subtype RGCs and vision against chronic IOP elevation. Methods We induced modest and sustained IOP elevation by laser illumination and microbead injection in mice. Using a tamoxifen-induced Cre recombinase system, BDNF was upregulated in the mouse retina when sustained IOP elevation was induced. We then examined whether overexpression of BDNF protected RGCs and vision during the period of ocular hypertension. Given that BDNF modulates axon growth and dendritic formation in a subtype-dependent manner, we tested whether BDNF protects RGC dendritic structure against the hypertensive insult also in a subtype-dependent manner. Results Sustained IOP elevation was induced and lasted up to 6 months. Overexpression of BDNF delayed progressive RGC and axon loss in hypertensive eyes. Brain-derived neurotrophic factor overexpression also helped to preserve acuity against the chronic hypertensive insult. We classified RGCs into ON and ON–OFF subtypes based on their dendritic lamination pattern in the inner plexiform layer and found that BDNF prevented ON–RGC dendritic degeneration in mice with sustained ocular hypertension. Conclusions Our data demonstrated that BDNF can protect the dendritic fields of ON RGCs and reduce RGC and vision loss in mice with sustained ocular hypertension.
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Affiliation(s)
- Liang Feng
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States 2Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, Illinois, United States
| | - Hui Chen
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Ji Yi
- Department of Biomedical Engineering, Robert R. McCormick School of Engineering and Applied Science, Northwestern University, Evanston, Illinois, United States
| | - John B Troy
- Department of Biomedical Engineering, Robert R. McCormick School of Engineering and Applied Science, Northwestern University, Evanston, Illinois, United States
| | - Hao F Zhang
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States 3Department of Biomedical Engineering, Robert R. McCormick School of Engineering and Applied Science, Northwestern University, Evanston, Il
| | - Xiaorong Liu
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States 2Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, Illinois, United States
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84
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Oliveira AV, Rosa da Costa AM, Silva GA. Non-viral strategies for ocular gene delivery. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017; 77:1275-1289. [PMID: 28532005 DOI: 10.1016/j.msec.2017.04.068] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 04/11/2017] [Accepted: 04/13/2017] [Indexed: 02/08/2023]
Abstract
The success of gene therapy relies on efficient gene transfer and stable transgene expression. The in vivo efficiency is determined by the delivery vector, route of administration, therapeutic gene, and target cells. While some requirements are common to several strategies, others depend on the target disease and transgene product. Consequently, it is unlikely that a single system is suitable for all applications. This review examines current gene therapy strategies, focusing on non-viral approaches and the use of natural polymers with the eye, and particularly the retina, as their gene delivery target.
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Affiliation(s)
- Ana V Oliveira
- Center for Biomedical Research (CBMR), University of Algarve, Faro 8005-139, Portugal
| | - Ana M Rosa da Costa
- Department of Chemistry and Pharmacy, University of Algarve, Faro 8005-139, Portugal; Algarve Chemistry Research Centre (CIQA), University of Algarve, Faro 8005-139, Portugal
| | - Gabriela A Silva
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisboa, Portugal.
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85
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Tejeda GS, Díaz-Guerra M. Integral Characterization of Defective BDNF/TrkB Signalling in Neurological and Psychiatric Disorders Leads the Way to New Therapies. Int J Mol Sci 2017; 18:ijms18020268. [PMID: 28134845 PMCID: PMC5343804 DOI: 10.3390/ijms18020268] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 01/15/2017] [Accepted: 01/23/2017] [Indexed: 11/23/2022] Open
Abstract
Enhancement of brain-derived neurotrophic factor (BDNF) signalling has great potential in therapy for neurological and psychiatric disorders. This neurotrophin not only attenuates cell death but also promotes neuronal plasticity and function. However, an important challenge to this approach is the persistence of aberrant neurotrophic signalling due to a defective function of the BDNF high-affinity receptor, tropomyosin-related kinase B (TrkB), or downstream effectors. Such changes have been already described in several disorders, but their importance as pathological mechanisms has been frequently underestimated. This review highlights the relevance of an integrative characterization of aberrant BDNF/TrkB pathways for the rational design of therapies that by combining BDNF and TrkB targets could efficiently promote neurotrophic signalling.
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Affiliation(s)
- Gonzalo S Tejeda
- Instituto de Investigaciones Biomédicas "Alberto Sols", Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain.
| | - Margarita Díaz-Guerra
- Instituto de Investigaciones Biomédicas "Alberto Sols", Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain.
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86
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Overexpression of Brain-Derived Neurotrophic Factor Protects Large Retinal Ganglion Cells After Optic Nerve Crush in Mice. eNeuro 2017; 4:eN-NWR-0331-16. [PMID: 28101532 PMCID: PMC5240030 DOI: 10.1523/eneuro.0331-16.2016] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/21/2016] [Accepted: 12/28/2016] [Indexed: 12/18/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF), a neurotrophin essential for neuron survival and function, plays an important role in neuroprotection during neurodegenerative diseases. In this study, we examined whether a modest increase of retinal BDNF promotes retinal ganglion cell (RGC) survival after acute injury of the optic nerve in mice. We adopted an inducible Cre-recombinase transgenic system to up-regulate BDNF in the mouse retina and then examined RGC survival after optic nerve crush by in vivo imaging. We focused on one subtype of RGC with large soma expressing yellow fluorescent protein transgene that accounts for ∼11% of the total SMI-32-positive RGCs. The median survival time of this subgroup of SMI-32 cells was 1 week after nerve injury in control mice but 2 weeks when BDNF was up-regulated. Interestingly, we found that the survival time for RGCs taken as a whole was 2 weeks, suggesting that these large-soma RGCs are especially vulnerable to optic nerve crush injury. We also studied changes in axon number using confocal imaging, confirming first the progressive loss reported previously for wild-type mice and demonstrating that BDNF up-regulation extended axon survival. Together, our results demonstrate that the time course of RGC loss induced by optic nerve injury is type specific and that overexpression of BDNF prolongs the survival of one subgroup of SMI-32-positive RGCs.
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87
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Protecting retinal ganglion cells. Eye (Lond) 2017; 31:218-224. [PMID: 28085136 DOI: 10.1038/eye.2016.299] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 11/26/2016] [Indexed: 01/08/2023] Open
Abstract
Retinal ganglion cell degeneration underlies several conditions which give rise to significant visual compromise, including glaucoma, hereditary optic neuropathies, ischaemic optic neuropathies, and demyelinating disease. In this review, we discuss the emerging strategies for neuroprotection specifically in the context of glaucoma, including pharmacological neuroprotection, mesenchymal stem cells, and gene therapy approaches. We highlight potential pitfalls that need to be considered when developing these strategies and outline future directions, including the prospects for clinical trials.
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88
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Jindal N, Banik A, Prabhakar S, Vaiphie K, Anand A. Alteration of Neurotrophic Factors After Transplantation of Bone Marrow Derived Lin-ve Stem Cell in NMDA-Induced Mouse Model of Retinal Degeneration. J Cell Biochem 2017; 118:1699-1711. [PMID: 27935095 DOI: 10.1002/jcb.25827] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 12/06/2016] [Indexed: 02/02/2023]
Abstract
Retinal ganglion cell layer (RGCs) is one of the important layers of retina, depleted in Glaucoma. Loss of RGC neurons is a major cellular mechanism involved in its pathogenesis resulting in severe vision loss. Stem cell therapy has emerged as a potential strategy to arrest the apoptotic loss of RGCs and also replace the degenerative cells in damaged retina. Here, we have investigated the incorporation and survival of mouse bone marrow derived Lin-ve stem cells in N-methyl-d-aspartate (NMDA)-induced mouse model of retinal degeneration. Two days after intravitreal injection of NMDA (100 mM) showed significant decrease in ganglion cell number and increase in TUNEL positive apoptotic cells in retinal layers. The injury was further characterized by immunohistochemical expression of Brn3b, GFAP, Bcl2, pCREB, CNTF, GDNF, and BDNF in retinal layers. Lin-ve cells (100,000 dose) were intravitreally transplanted after 2 days of injury and evaluated after 7, 14, and 21 days of transplantation. Transplanted cells were found to have migrated from intravitreal space and incorporated into injured retina at 7, 14, and 21 days post-transplantation. At 21 days Brn3b, CNTF, and BDNF expression was found to be upregulated whereas GDNF was downregulated when compared to respective injury time points. Molecular data showed decrease in the expression of Brn3b, BDNF, CNTF, and GDNF post transplantation when compared with injury groups. This study reveals that Lin-ve stem cells may exert neuroprotective effect in damaged retina mediated by participation of neurotrophic factors induced by stem cell transplantation at the site of injury. J. Cell. Biochem. 118: 1699-1711, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Neeru Jindal
- Neuroscience Research Lab, Department of Neurology, PGIMER, Chandigarh 160012, India
| | - Avijit Banik
- Neuroscience Research Lab, Department of Neurology, PGIMER, Chandigarh 160012, India
| | - Sudesh Prabhakar
- Neuroscience Research Lab, Department of Neurology, PGIMER, Chandigarh 160012, India
| | - Kim Vaiphie
- Department of Histopathology, PGIMER, Chandigarh 160012, India
| | - Akshay Anand
- Neuroscience Research Lab, Department of Neurology, PGIMER, Chandigarh 160012, India
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89
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Targeting retinal ganglion cell recovery. Eye (Lond) 2017; 31:196-198. [PMID: 28060359 DOI: 10.1038/eye.2016.281] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 10/30/2016] [Indexed: 11/08/2022] Open
Abstract
Accumulating evidence from experimental and clinical studies suggest that retinal ganglion cells at least in the earlier stages of glaucoma have the capacity to recover function following periods of functional loss. The capacity for recovery may be negatively impacted by advancing age but can be boosted by interventions such as diet restriction and exercise.
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90
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Borrás T. The Pathway From Genes to Gene Therapy in Glaucoma: A Review of Possibilities for Using Genes as Glaucoma Drugs. Asia Pac J Ophthalmol (Phila) 2017; 6:80-93. [PMID: 28161916 PMCID: PMC6005701 DOI: 10.22608/apo.2016126] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Accepted: 09/27/2016] [Indexed: 12/19/2022] Open
Abstract
Treatment of diseases with gene therapy is advancing rapidly. The use of gene therapy has expanded from the original concept of re-placing the mutated gene causing the disease to the use of genes to con-trol nonphysiological levels of expression or to modify pathways known to affect the disease. Genes offer numerous advantages over conventional drugs. They have longer duration of action and are more specific. Genes can be delivered to the target site by naked DNA, cells, nonviral, and viral vectors. The enormous progress of the past decade in molecular bi-ology and delivery systems has provided ways for targeting genes to the intended cell/tissue and safe, long-term vectors. The eye is an ideal organ for gene therapy. It is easily accessible and it is an immune-privileged site. Currently, there are clinical trials for diseases affecting practically every tissue of the eye, including those to restore vision in patients with Leber congenital amaurosis. However, the number of eye trials compared with those for systemic diseases is quite low (1.8%). Nevertheless, judg-ing by the vast amount of ongoing preclinical studies, it is expected that such number will increase considerably in the near future. One area of great need for eye gene therapy is glaucoma, where a long-term gene drug would eliminate daily applications and compliance issues. Here, we review the current state of gene therapy for glaucoma and the possibilities for treating the trabecular meshwork to lower intraocular pressure and the retinal ganglion cells to protect them from neurodegeneration.
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Affiliation(s)
- Teresa Borrás
- Department of Ophthalmology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
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91
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Levin LA, Crowe ME, Quigley HA. Neuroprotection for glaucoma: Requirements for clinical translation. Exp Eye Res 2016; 157:34-37. [PMID: 27955999 DOI: 10.1016/j.exer.2016.12.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 10/06/2016] [Accepted: 12/09/2016] [Indexed: 11/17/2022]
Abstract
Within the field of glaucoma research, neuroprotection is defined as slowing the functional loss in glaucoma by a mechanism independent of lowering of intraocular pressure. There is currently a great potential for research surrounding neuroprotection as it relates to glaucoma. Anatomical targets for neuroprotection should focus on upstream rather than downstream factors, and could include any part of the retinal ganglion cell, the glia, especially astrocytes or Muller cells, and vasculature. The great number of anatomical targets is exceeded only by the number of possible biochemical pathways and potential treatments. Successful treatment may be accomplished through the targeting of one or even a combination of multiple pathways. Once a treatment is shown effective in vitro, it should be evaluated in vivo with carefully chosen animal models and studied in sufficient numbers to detect statistically and clinically significant effects. Such a drug should have few systemic side effects and its delivery should be optimized so as to encourage compliance. There are still a multitude of possible screens available to test the efficacy of a neuroprotective drug and a single gold standard is ideal for the accurate assessment and comparison of new drugs. Future studies in neuroprotection should investigate the genetic component of the disease, novel pharmaceutical agents for new or known pathways, modulations of scleral biomechanics, and relation to research of other complex disorders of the central nervous system.
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Affiliation(s)
- Leonard A Levin
- Department of Ophthalmology, McGill University, Montreal, Quebec, Canada; Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
| | - Megan E Crowe
- Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Harry A Quigley
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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92
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Mysona BA, Zhao J, Bollinger KE. Role of BDNF/TrkB pathway in the visual system: Therapeutic implications for glaucoma. EXPERT REVIEW OF OPHTHALMOLOGY 2016; 12:69-81. [PMID: 28751923 DOI: 10.1080/17469899.2017.1259566] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Neuroprotective therapeutics are needed to treat glaucoma, an optic neuropathy that results in death of retinal ganglion cells (RGCs). AREAS COVERED The BDNF/TrkB pathway is important for RGC survival. Temporal and spatial alterations in the BDNF/TrkB pathway occur in development and in response to acute optic nerve injury and to glaucoma. In animal models, BDNF supplementation is successful at slowing RGC death after acute optic nerve injury and in glaucoma, however, the BDNF/TrkB signaling is not the only pathway supporting long term RGC survival. EXPERT COMMENTARY Much remains to be discovered about the interaction between retrograde, anterograde, and retinal BDNF/TrkB signaling pathways in both neurons and glia. An ideal therapeutic agent for glaucoma likely has several modes of action that target multiple mechanisms of neurodegeneration including the BDNF/TrkB pathway.
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Affiliation(s)
- B A Mysona
- Augusta University Department of Cellular Biology and Anatomy, James and Jean Culver Vision Discovery Institute. Address: Augusta University Department of Cellular Biology and Anatomy, Health Sciences Campus, 1120 15th Street, Augusta, GA 30912, USA,
| | - J Zhao
- Medical College of Georgia, Department of Ophthalmology at Augusta University, James and Jean Culver Vision Discovery Institute. Address: Medical College of Georgia, Department of Ophthalmology at Augusta University, 1120 15th Street, Augusta, GA 30912, USA,
| | - K E Bollinger
- Medical College of Georgia, Department of Ophthalmology at Augusta University, Augusta University Department of Cellular Biology and Anatomy, James and Jean Culver Vision Discovery Institute. Address: Medical College of Georgia, Department of Ophthalmology at Augusta University, 1120 15th Street, Augusta, GA 30912, USA,
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93
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Weinreb RN, Leung CKS, Crowston JG, Medeiros FA, Friedman DS, Wiggs JL, Martin KR. Primary open-angle glaucoma. Nat Rev Dis Primers 2016; 2:16067. [PMID: 27654570 DOI: 10.1038/nrdp.2016.67] [Citation(s) in RCA: 272] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Glaucoma is an optic neuropathy that is characterized by the progressive degeneration of the optic nerve, leading to visual impairment. Glaucoma is the main cause of irreversible blindness worldwide, but typically remains asymptomatic until very severe. Open-angle glaucoma comprises the majority of cases in the United States and western Europe, of which, primary open-angle glaucoma (POAG) is the most common type. By contrast, in China and other Asian countries, angle-closure glaucoma is highly prevalent. These two types of glaucoma are characterized based on the anatomic configuration of the aqueous humour outflow pathway. The pathophysiology of POAG is not well understood, but it is an optic neuropathy that is thought to be associated with intraocular pressure (IOP)-related damage to the optic nerve head and resultant loss of retinal ganglion cells (RGCs). POAG is generally diagnosed during routine eye examination, which includes fundoscopic evaluation and visual field assessment (using perimetry). An increase in IOP, measured by tonometry, is not essential for diagnosis. Management of POAG includes topical drug therapies and surgery to reduce IOP, although new therapies targeting neuroprotection of RGCs and axonal regeneration are under development.
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Affiliation(s)
- Robert N Weinreb
- Shiley Eye Institute, Hamilton Glaucoma Center, Department of Ophthalmology, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - Christopher K S Leung
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Jonathan G Crowston
- Department of Ophthalmology, Centre for Eye Research Australia, University of Melbourne, Melbourne, Victoria, Australia
| | - Felipe A Medeiros
- Shiley Eye Institute, Hamilton Glaucoma Center, Department of Ophthalmology, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - David S Friedman
- Dana Center for Preventive Ophthalmology, Johns Hopkins Wilmer Eye Institute, Baltimore, Maryland, USA
| | - Janey L Wiggs
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, USA
| | - Keith R Martin
- Department of Ophthalmology and Cambridge NIHR Biomedical Research Centre, University of Cambridge, Cambridge, UK
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94
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Kimura A, Namekata K, Guo X, Harada C, Harada T. Neuroprotection, Growth Factors and BDNF-TrkB Signalling in Retinal Degeneration. Int J Mol Sci 2016; 17:ijms17091584. [PMID: 27657046 PMCID: PMC5037849 DOI: 10.3390/ijms17091584] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 09/01/2016] [Accepted: 09/14/2016] [Indexed: 12/18/2022] Open
Abstract
Neurotrophic factors play key roles in the development and survival of neurons. The potent neuroprotective effects of neurotrophic factors, including brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF), glial cell-line derived neurotrophic factor (GDNF) and nerve growth factor (NGF), suggest that they are good therapeutic candidates for neurodegenerative diseases. Glaucoma is a neurodegenerative disease of the eye that causes irreversible blindness. It is characterized by damage to the optic nerve, usually due to high intraocular pressure (IOP), and progressive degeneration of retinal neurons called retinal ganglion cells (RGCs). Current therapy for glaucoma focuses on reduction of IOP, but neuroprotection may also be beneficial. BDNF is a powerful neuroprotective agent especially for RGCs. Exogenous application of BDNF to the retina and increased BDNF expression in retinal neurons using viral vector systems are both effective in protecting RGCs from damage. Furthermore, induction of BDNF expression by agents such as valproic acid has also been beneficial in promoting RGC survival. In this review, we discuss the therapeutic potential of neurotrophic factors in retinal diseases and focus on the differential roles of glial and neuronal TrkB in neuroprotection. We also discuss the role of neurotrophic factors in neuroregeneration.
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Affiliation(s)
- Atsuko Kimura
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
| | - Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
| | - Xiaoli Guo
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
| | - Chikako Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
| | - Takayuki Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
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95
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Exogenous Modulation of Retinoic Acid Signaling Affects Adult RGC Survival in the Frog Visual System after Optic Nerve Injury. PLoS One 2016; 11:e0162626. [PMID: 27611191 PMCID: PMC5017682 DOI: 10.1371/journal.pone.0162626] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 08/25/2016] [Indexed: 02/04/2023] Open
Abstract
After lesions to the mammalian optic nerve, the great majority of retinal ganglion cells (RGCs) die before their axons have even had a chance to regenerate. Frog RGCs, on the other hand, suffer only an approximately 50% cell loss, and we have previously investigated the mechanisms by which the application of growth factors can increase their survival rate. Retinoic acid (RA) is a vitamin A-derived lipophilic molecule that plays major roles during development of the nervous system. The RA signaling pathway is also present in parts of the adult nervous system, and components of it are upregulated after injury in peripheral nerves but not in the CNS. Here we investigate whether RA signaling affects long-term RGC survival at 6 weeks after axotomy. Intraocular injection of all-trans retinoic acid (ATRA), the retinoic acid receptor (RAR) type-α agonist AM80, the RARβ agonist CD2314, or the RARγ agonist CD1530, returned axotomized RGC numbers to almost normal levels. On the other hand, inhibition of RA synthesis with disulfiram, or of RAR receptors with the pan-RAR antagonist Ro-41-5253, or the RARβ antagonist LE135E, greatly reduced the survival of the axotomized neurons. Axotomy elicited a strong activation of the MAPK, STAT3 and AKT pathways; this activation was prevented by disulfiram or by RAR antagonists. Finally, addition of exogenous ATRA stimulated the activation of the first two of these pathways. Future experiments will investigate whether these strong survival-promoting effects of RA are mediated via the upregulation of neurotrophins.
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96
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Hickmott JW, Chen CY, Arenillas DJ, Korecki AJ, Lam SL, Molday LL, Bonaguro RJ, Zhou M, Chou AY, Mathelier A, Boye SL, Hauswirth WW, Molday RS, Wasserman WW, Simpson EM. PAX6 MiniPromoters drive restricted expression from rAAV in the adult mouse retina. Mol Ther Methods Clin Dev 2016; 3:16051. [PMID: 27556059 PMCID: PMC4980111 DOI: 10.1038/mtm.2016.51] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/25/2016] [Accepted: 06/13/2016] [Indexed: 12/15/2022]
Abstract
Current gene therapies predominantly use small, strong, and readily available ubiquitous promoters. However, as the field matures, the availability of small, cell-specific promoters would be greatly beneficial. Here we design seven small promoters from the human paired box 6 (PAX6) gene and test them in the adult mouse retina using recombinant adeno-associated virus. We chose the retina due to previous successes in gene therapy for blindness, and the PAX6 gene since it is: well studied; known to be driven by discrete regulatory regions; expressed in therapeutically interesting retinal cell types; and mutated in the vision-loss disorder aniridia, which is in need of improved therapy. At the PAX6 locus, 31 regulatory regions were bioinformatically predicted, and nine regulatory regions were constructed into seven MiniPromoters. Driving Emerald GFP, these MiniPromoters were packaged into recombinant adeno-associated virus, and injected intravitreally into postnatal day 14 mice. Four MiniPromoters drove consistent retinal expression in the adult mouse, driving expression in combinations of cell-types that endogenously express Pax6: ganglion, amacrine, horizontal, and Müller glia. Two PAX6-MiniPromoters drive expression in three of the four cell types that express PAX6 in the adult mouse retina. Combined, they capture all four cell types, making them potential tools for research, and PAX6-gene therapy for aniridia.
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Affiliation(s)
- Jack W Hickmott
- Centre for Molecular Medicine and Therapeutics at the BC Children’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Chih-yu Chen
- Centre for Molecular Medicine and Therapeutics at the BC Children’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Graduate Program in Bioinformatics, University of British Columbia, Vancouver, British Columbia, Canada
| | - David J Arenillas
- Centre for Molecular Medicine and Therapeutics at the BC Children’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Andrea J Korecki
- Centre for Molecular Medicine and Therapeutics at the BC Children’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Siu Ling Lam
- Centre for Molecular Medicine and Therapeutics at the BC Children’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Laurie L Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Russell J Bonaguro
- Centre for Molecular Medicine and Therapeutics at the BC Children’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michelle Zhou
- Centre for Molecular Medicine and Therapeutics at the BC Children’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alice Y Chou
- Centre for Molecular Medicine and Therapeutics at the BC Children’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Anthony Mathelier
- Centre for Molecular Medicine and Therapeutics at the BC Children’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sanford L Boye
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - William W Hauswirth
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Robert S Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Wyeth W Wasserman
- Centre for Molecular Medicine and Therapeutics at the BC Children’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Elizabeth M Simpson
- Centre for Molecular Medicine and Therapeutics at the BC Children’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada
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97
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Foldvari M, Chen DW. The intricacies of neurotrophic factor therapy for retinal ganglion cell rescue in glaucoma: a case for gene therapy. Neural Regen Res 2016; 11:875-7. [PMID: 27482199 PMCID: PMC4962568 DOI: 10.4103/1673-5374.184448] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Regeneration of damaged retinal ganglion cells (RGC) and their axons is an important aspect of reversing vision loss in glaucoma patients. While current therapies can effectively lower intraocular pressure, they do not provide extrinsic support to RGCs to actively aid in their protection and regeneration. The unmet need could be addressed by neurotrophic factor gene therapy, where plasmid DNA, encoding neurotrophic factors, is delivered to retinal cells to maintain sufficient levels of neurotrophins in the retina. In this review, we aim to describe the intricacies in the design of the therapy including: the choice of neurotrophic factor, the site and route of administration and target cell populations for gene delivery. Furthermore, we also discuss the challenges currently being faced in RGC-related therapy development with special considerations to the existence of multiple RGC subtypes and the lack of efficient and representative in vitro models for rapid and reliable screening in the drug development process.
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Affiliation(s)
- Marianna Foldvari
- School of Pharmacy, Waterloo Institute of Nanotechnology and Center for Bioengineering and Biotechnology, University of Waterloo, Waterloo, ON, Canada
| | - Ding Wen Chen
- School of Pharmacy, Waterloo Institute of Nanotechnology and Center for Bioengineering and Biotechnology, University of Waterloo, Waterloo, ON, Canada
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98
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Wu N, Wang Y, Yang L, Cho KS. Signaling Networks of Retinal Ganglion Cell Formation and the Potential Application of Stem Cell–Based Therapy in Retinal Degenerative Diseases. Hum Gene Ther 2016; 27:609-20. [PMID: 27466076 DOI: 10.1089/hum.2016.083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Affiliation(s)
- Nan Wu
- 1 Department of Ophthalmology, Southwest Eye Hospital, Southwest Hospital, Third Military Medical University , Chongqing, China
| | - Yi Wang
- 1 Department of Ophthalmology, Southwest Eye Hospital, Southwest Hospital, Third Military Medical University , Chongqing, China
| | - Lanbo Yang
- 2 Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School , Boston, Massachusetts
| | - Kin-Sang Cho
- 2 Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School , Boston, Massachusetts
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99
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Quigley HA. Understanding Glaucomatous Optic Neuropathy: The Synergy Between Clinical Observation and Investigation. Annu Rev Vis Sci 2016; 2:235-254. [PMID: 28532352 DOI: 10.1146/annurev-vision-111815-114417] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Glaucoma is a complex disorder of aging defined by the death of retinal ganglion cells and remodeling of connective tissues at the optic nerve head. Intraocular pressure-induced axonal injury at the optic nerve head leads to apoptosis. Loss of retinal ganglion cells follows a slowly progressive sequence. Clinical features of the disease have suggested and corroborated pathological events. The death of retinal ganglion cells causes secondary loss of neurons in the brain, but only as a by-product of injury to the retinal ganglion cells. Although therapy to lower intraocular pressure is moderately effective, new treatments are being developed to alter the remodeling of ocular connective tissue, to interrupt the injury signal from axon to soma, and to upregulate a variety of survival mechanisms.
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Affiliation(s)
- Harry A Quigley
- Glaucoma Center of Excellence, Wilmer Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287;
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100
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Piri N, Kwong JMK, Gu L, Caprioli J. Heat shock proteins in the retina: Focus on HSP70 and alpha crystallins in ganglion cell survival. Prog Retin Eye Res 2016; 52:22-46. [PMID: 27017896 PMCID: PMC4842330 DOI: 10.1016/j.preteyeres.2016.03.001] [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: 01/31/2016] [Revised: 03/14/2016] [Accepted: 03/22/2016] [Indexed: 10/22/2022]
Abstract
Heat shock proteins (HSPs) belong to a superfamily of stress proteins that are critical constituents of a complex defense mechanism that enhances cell survival under adverse environmental conditions. Cell protective roles of HSPs are related to their chaperone functions, antiapoptotic and antinecrotic effects. HSPs' anti-apoptotic and cytoprotective characteristics, their ability to protect cells from a variety of stressful stimuli, and the possibility of their pharmacological induction in cells under pathological stress make these proteins an attractive therapeutic target for various neurodegenerative diseases; these include Alzheimer's, Parkinson's, Huntington's, prion disease, and others. This review discusses the possible roles of HSPs, particularly HSP70 and small HSPs (alpha A and alpha B crystallins) in enhancing the survival of retinal ganglion cells (RGCs) in optic neuropathies such as glaucoma, which is characterized by progressive loss of vision caused by degeneration of RGCs and their axons in the optic nerve. Studies in animal models of RGC degeneration induced by ocular hypertension, optic nerve crush and axotomy show that upregulation of HSP70 expression by hyperthermia, zinc, geranyl-geranyl acetone, 17-AAG (a HSP90 inhibitor), or through transfection of retinal cells with AAV2-HSP70 effectively supports the survival of injured RGCs. RGCs survival was also stimulated by overexpression of alpha A and alpha B crystallins. These findings provide support for translating the HSP70- and alpha crystallin-based cell survival strategy into therapy to protect and rescue injured RGCs from degeneration associated with glaucomatous and other optic neuropathies.
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Affiliation(s)
- Natik Piri
- Stein Eye Institute, University of California, Los Angeles, CA 90095, USA; Brain Research Institute, University of California, Los Angeles, CA 90095, USA.
| | - Jacky M K Kwong
- Stein Eye Institute, University of California, Los Angeles, CA 90095, USA
| | - Lei Gu
- Stein Eye Institute, University of California, Los Angeles, CA 90095, USA
| | - Joseph Caprioli
- Stein Eye Institute, University of California, Los Angeles, CA 90095, USA; Brain Research Institute, University of California, Los Angeles, CA 90095, USA
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