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Bou Ghanem GO, Wareham LK, Calkins DJ. Addressing neurodegeneration in glaucoma: Mechanisms, challenges, and treatments. Prog Retin Eye Res 2024; 100:101261. [PMID: 38527623 DOI: 10.1016/j.preteyeres.2024.101261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/15/2024] [Accepted: 03/19/2024] [Indexed: 03/27/2024]
Abstract
Glaucoma is the leading cause of irreversible blindness globally. The disease causes vision loss due to neurodegeneration of the retinal ganglion cell (RGC) projection to the brain through the optic nerve. Glaucoma is associated with sensitivity to intraocular pressure (IOP). Thus, mainstay treatments seek to manage IOP, though many patients continue to lose vision. To address neurodegeneration directly, numerous preclinical studies seek to develop protective or reparative therapies that act independently of IOP. These include growth factors, compounds targeting metabolism, anti-inflammatory and antioxidant agents, and neuromodulators. Despite success in experimental models, many of these approaches fail to translate into clinical benefits. Several factors contribute to this challenge. Firstly, the anatomic structure of the optic nerve head differs between rodents, nonhuman primates, and humans. Additionally, animal models do not replicate the complex glaucoma pathophysiology in humans. Therefore, to enhance the success of translating these findings, we propose two approaches. First, thorough evaluation of experimental targets in multiple animal models, including nonhuman primates, should precede clinical trials. Second, we advocate for combination therapy, which involves using multiple agents simultaneously, especially in the early and potentially reversible stages of the disease. These strategies aim to increase the chances of successful neuroprotective treatment for glaucoma.
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Affiliation(s)
- Ghazi O Bou Ghanem
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Lauren K Wareham
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - David J Calkins
- Vanderbilt Eye Institute, Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
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2
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Benowitz LI, Xie L, Yin Y. Inflammatory Mediators of Axon Regeneration in the Central and Peripheral Nervous Systems. Int J Mol Sci 2023; 24:15359. [PMID: 37895039 PMCID: PMC10607492 DOI: 10.3390/ijms242015359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/13/2023] [Accepted: 10/13/2023] [Indexed: 10/29/2023] Open
Abstract
Although most pathways in the mature central nervous system cannot regenerate when injured, research beginning in the late 20th century has led to discoveries that may help reverse this situation. Here, we highlight research in recent years from our laboratory identifying oncomodulin (Ocm), stromal cell-derived factor (SDF)-1, and chemokine CCL5 as growth factors expressed by cells of the innate immune system that promote axon regeneration in the injured optic nerve and elsewhere in the central and peripheral nervous systems. We also review the role of ArmC10, a newly discovered Ocm receptor, in mediating many of these effects, and the synergy between inflammation-derived growth factors and complementary strategies to promote regeneration, including deleting genes encoding cell-intrinsic suppressors of axon growth, manipulating transcription factors that suppress or promote the expression of growth-related genes, and manipulating cell-extrinsic suppressors of axon growth. In some cases, combinatorial strategies have led to unprecedented levels of nerve regeneration. The identification of some similar mechanisms in human neurons offers hope that key discoveries made in animal models may eventually lead to treatments to improve outcomes after neurological damage in patients.
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Affiliation(s)
- Larry I. Benowitz
- Department of Neurosurgery, Boston Children’s Hospital, Boston, MA 02115, USA; (L.X.); (Y.Y.)
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Neurosurgery, Harvard Medical School, Boston, MA 02115, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA 02115, USA
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | - Lili Xie
- Department of Neurosurgery, Boston Children’s Hospital, Boston, MA 02115, USA; (L.X.); (Y.Y.)
- Department of Neurosurgery, Harvard Medical School, Boston, MA 02115, USA
- Department of Ophthalmology, Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Yuqin Yin
- Department of Neurosurgery, Boston Children’s Hospital, Boston, MA 02115, USA; (L.X.); (Y.Y.)
- Department of Neurosurgery, Harvard Medical School, Boston, MA 02115, USA
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3
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Wong KA, Benowitz LI. Retinal Ganglion Cell Survival and Axon Regeneration after Optic Nerve Injury: Role of Inflammation and Other Factors. Int J Mol Sci 2022; 23:ijms231710179. [PMID: 36077577 PMCID: PMC9456227 DOI: 10.3390/ijms231710179] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/29/2022] [Accepted: 09/02/2022] [Indexed: 11/24/2022] Open
Abstract
The optic nerve, like most pathways in the mature central nervous system, cannot regenerate if injured, and within days, retinal ganglion cells (RGCs), the neurons that extend axons through the optic nerve, begin to die. Thus, there are few clinical options to improve vision after traumatic or ischemic optic nerve injury or in neurodegenerative diseases such as glaucoma, dominant optic neuropathy, or optic pathway gliomas. Research over the past two decades has identified several strategies to enable RGCs to regenerate axons the entire length of the optic nerve, in some cases leading to modest reinnervation of di- and mesencephalic visual relay centers. This review primarily focuses on the role of the innate immune system in improving RGC survival and axon regeneration, and its synergy with manipulations of signal transduction pathways, transcription factors, and cell-extrinsic suppressors of axon growth. Research in this field provides hope that clinically effective strategies to improve vision in patients with currently untreatable losses could become a reality in 5-10 years.
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Affiliation(s)
- Kimberly A. Wong
- Department of Neurosurgery, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
- Correspondence: (K.A.W.); (L.I.B.)
| | - Larry I. Benowitz
- Department of Neurosurgery, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA 02115, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA 02115, USA
- Correspondence: (K.A.W.); (L.I.B.)
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4
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Jacobi A, Tran NM, Yan W, Benhar I, Tian F, Schaffer R, He Z, Sanes JR. Overlapping transcriptional programs promote survival and axonal regeneration of injured retinal ganglion cells. Neuron 2022; 110:2625-2645.e7. [PMID: 35767994 PMCID: PMC9391321 DOI: 10.1016/j.neuron.2022.06.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 04/08/2022] [Accepted: 06/03/2022] [Indexed: 12/12/2022]
Abstract
Injured neurons in the adult mammalian central nervous system often die and seldom regenerate axons. To uncover transcriptional pathways that could ameliorate these disappointing responses, we analyzed three interventions that increase survival and regeneration of mouse retinal ganglion cells (RGCs) following optic nerve crush (ONC) injury, albeit not to a clinically useful extent. We assessed gene expression in each of 46 RGC types by single-cell transcriptomics following ONC and treatment. We also compared RGCs that regenerated with those that survived but did not regenerate. Each intervention enhanced survival of most RGC types, but type-independent axon regeneration required manipulation of multiple pathways. Distinct computational methods converged on separate sets of genes selectively expressed by RGCs likely to be dying, surviving, or regenerating. Overexpression of genes associated with the regeneration program enhanced both survival and axon regeneration in vivo, indicating that mechanistic analysis can be used to identify novel therapeutic strategies.
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Affiliation(s)
- Anne Jacobi
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, and Department of Neurology, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
| | - Nicholas M Tran
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA
| | - Wenjun Yan
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
| | - Inbal Benhar
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Feng Tian
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, and Department of Neurology, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Rebecca Schaffer
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
| | - Zhigang He
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, and Department of Neurology, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA.
| | - Joshua R Sanes
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA.
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5
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Monocyte-derived SDF1 supports optic nerve regeneration and alters retinal ganglion cells' response to Pten deletion. Proc Natl Acad Sci U S A 2022; 119:e2113751119. [PMID: 35394873 PMCID: PMC9169637 DOI: 10.1073/pnas.2113751119] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Although mammalian retinal ganglion cells (RGCs) normally cannot regenerate axons nor survive after optic nerve injury, this failure is partially reversed by inducing sterile inflammation in the eye. Infiltrative myeloid cells express the axogenic protein oncomodulin (Ocm) but additional, as-yet-unidentified, factors are also required. We show here that infiltrative macrophages express stromal cell–derived factor 1 (SDF1, CXCL12), which plays a central role in this regard. Among many growth factors tested in culture, only SDF1 enhances Ocm activity, an effect mediated through intracellular cyclic AMP (cAMP) elevation and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) activation. SDF1 deficiency in myeloid cells (CXCL12flx/flxLysM-Cre−/+ mice) or deletion of the SDF1 receptor CXCR4 in RGCs (intraocular AAV2-Cre in CXCR4flx/flx mice) or SDF1 antagonist AMD3100 greatly suppresses inflammation-induced regeneration and decreases RGC survival to baseline levels. Conversely, SDF1 induces optic nerve regeneration and RGC survival, and, when combined with Ocm/cAMP, SDF1 increases axon regeneration to levels similar to those induced by intraocular inflammation. In contrast to deletion of phosphatase and tensin homolog (Pten), which promotes regeneration selectively from αRGCs, SDF1 promotes regeneration from non-αRGCs and enables the latter cells to respond robustly to Pten deletion; however, SDF1 surprisingly diminishes the response of αRGCs to Pten deletion. When combined with inflammation and Pten deletion, SDF1 enables many RGCs to regenerate axons the entire length of the optic nerve. Thus, SDF1 complements the effects of Ocm in mediating inflammation-induced regeneration and enables different RGC subtypes to respond to Pten deletion.
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6
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Cell-Based Neuroprotection of Retinal Ganglion Cells in Animal Models of Optic Neuropathies. BIOLOGY 2021; 10:biology10111181. [PMID: 34827174 PMCID: PMC8615038 DOI: 10.3390/biology10111181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/10/2021] [Accepted: 11/11/2021] [Indexed: 11/16/2022]
Abstract
Retinal ganglion cells (RGCs) comprise a heterogenous group of projection neurons that transmit visual information from the retina to the brain. Progressive degeneration of these cells, as it occurs in inflammatory, ischemic, traumatic or glaucomatous optic neuropathies, results in visual deterioration and is among the leading causes of irreversible blindness. Treatment options for these diseases are limited. Neuroprotective approaches aim to slow down and eventually halt the loss of ganglion cells in these disorders. In this review, we have summarized preclinical studies that have evaluated the efficacy of cell-based neuroprotective treatment strategies to rescue retinal ganglion cells from cell death. Intraocular transplantations of diverse genetically nonmodified cell types or cells engineered to overexpress neurotrophic factors have been demonstrated to result in significant attenuation of ganglion cell loss in animal models of different optic neuropathies. Cell-based combinatorial neuroprotective approaches represent a potential strategy to further increase the survival rates of retinal ganglion cells. However, data about the long-term impact of the different cell-based treatment strategies on retinal ganglion cell survival and detailed analyses of potential adverse effects of a sustained intraocular delivery of neurotrophic factors on retina structure and function are limited, making it difficult to assess their therapeutic potential.
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7
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Wang D, Luo M, Huang B, Gao W, Jiang Y, Li Q, Nan K, Lin S. Localized co-delivery of CNTF and FK506 using a thermosensitive hydrogel for retina ganglion cells protection after traumatic optic nerve injury. Drug Deliv 2021; 27:556-564. [PMID: 32351142 PMCID: PMC7241497 DOI: 10.1080/10717544.2020.1748759] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Following the traumatic axonal injury in the optic nerve, the failure of retrograde axonal transport to continuously supply neurotrophins from the brain to retina results in deprivation of neurotrophins in retinal ganglion cells (RGCs), which in turn can modulate the fate of RGCs toward apoptosis and thereby impede axon regeneration. In this study, a ciliary neurotrophic factor (CNTF) loaded thermo-sensitive hydrogel was designed and developed as a localized drug depot to restore neurotrophins supply following axon injury. Besides, following traumatic axon injury, overactive immune responses cause neurotoxicity and induce scar formation which together constitutes the major hindrances for axon regeneration. Thus, the FK506, a hydrophobic macrolide immunosuppressant, was co-loaded into the hydrogel after encapsulating it into a polymeric micelle. The materials can undergo sol-to-gel transition within minutes under a physiological pH of 37 °C. The release of drugs from the hydrogel exhibited a sustainable profile in vitro. The optic nerve was exposed by surgical procedure and the animal model was prepared by crushing the nerve with a reverse clamp. For the localized delivery to the optic nerve, a pre-hydrogel liquid containing chitosan, FK506 (in micelle), CNTF, and the gelling agent was directly smeared on the injured site, which gelled under physiological condition. This co-delivery system exhibited in vivo RGCs protective effect against the adverse effects caused by traumatic optic nerve injury, indicating the potential of this drug delivery system for effective optic nerve repair and this strategy may provide promising platforms for localized drug delivery in various other therapies.
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Affiliation(s)
- Dongmei Wang
- School of Ophthalmology & Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Mengmeng Luo
- School of Ophthalmology & Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,Wenzhou Institute, University of Chinese Academy of Science, Wenzhou, China
| | - Baoshan Huang
- School of Ophthalmology & Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,Wenzhou Institute, University of Chinese Academy of Science, Wenzhou, China
| | - Wa Gao
- School of Ophthalmology & Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Yan Jiang
- School of Ophthalmology & Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Qing Li
- School of Ophthalmology & Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou Medical University, Wenzhou, China
| | - Kaihui Nan
- School of Ophthalmology & Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou Medical University, Wenzhou, China.,Wenzhou Institute, University of Chinese Academy of Science, Wenzhou, China
| | - Sen Lin
- School of Ophthalmology & Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou Medical University, Wenzhou, China.,Wenzhou Institute, University of Chinese Academy of Science, Wenzhou, China
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8
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Fudalej E, Justyniarska M, Kasarełło K, Dziedziak J, Szaflik JP, Cudnoch-Jędrzejewska A. Neuroprotective Factors of the Retina and Their Role in Promoting Survival of Retinal Ganglion Cells: A Review. Ophthalmic Res 2021; 64:345-355. [PMID: 33454713 DOI: 10.1159/000514441] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 01/09/2021] [Indexed: 11/19/2022]
Abstract
Retinal ganglion cells (RGCs) play a crucial role in the visual pathway. As their axons form the optic nerve, apoptosis of these cells causes neurodegenerative vision loss. RGC death could be triggered by increased intraocular pressure, advanced glycation end products, or mitochondrial dysfunction. In this review, we summarize the role of some neuroprotective factors in RGC injury: ciliary neurotrophic factor (CNTF), nerve growth factor (NGF), brain-derived neurotrophic factor, vascular endothelial growth factor, pigment epithelium-derived factor, glial cell line-derived neurotrophic factor, and Norrin. Each, in their own unique way, prevents RGC damage caused by glaucoma, ocular hypertension, ischemic neuropathy, and even oxygen-induced retinopathy. These factors are produced mainly by neurons, leukocytes, glial cells, and epithelial cells. Neuroprotective factors act via various signaling pathways, including JAK/STAT, MAPK, TrkA, and TrkB, which promotes RGC survival. Many attempts have been made to develop therapeutic strategies using these factors. There are ongoing clinical trials with CNTF and NGF, but they have not yet been accepted for clinical use.
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Affiliation(s)
- Ewa Fudalej
- Department of Experimental and Clinical Physiology, Center for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Magdalena Justyniarska
- Department of Experimental and Clinical Physiology, Center for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Kaja Kasarełło
- Department of Experimental and Clinical Physiology, Center for Preclinical Research, Medical University of Warsaw, Warsaw, Poland,
| | - Jacek Dziedziak
- Department of Experimental and Clinical Physiology, Center for Preclinical Research, Medical University of Warsaw, Warsaw, Poland.,Department of Ophthalmology, SPKSO Ophthalmic University Hospital, Medical University of Warsaw, Warsaw, Poland
| | - Jacek P Szaflik
- Department of Ophthalmology, SPKSO Ophthalmic University Hospital, Medical University of Warsaw, Warsaw, Poland
| | - Agnieszka Cudnoch-Jędrzejewska
- Department of Experimental and Clinical Physiology, Center for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
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9
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Intravitreal Co-Administration of GDNF and CNTF Confers Synergistic and Long-Lasting Protection against Injury-Induced Cell Death of Retinal Ganglion Cells in Mice. Cells 2020; 9:cells9092082. [PMID: 32932933 PMCID: PMC7565883 DOI: 10.3390/cells9092082] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 09/03/2020] [Accepted: 09/09/2020] [Indexed: 12/15/2022] Open
Abstract
We have recently demonstrated that neural stem cell-based intravitreal co-administration of glial cell line-derived neurotrophic factor (GDNF) and ciliary neurotrophic factor (CNTF) confers profound protection to injured retinal ganglion cells (RGCs) in a mouse optic nerve crush model, resulting in the survival of ~38% RGCs two months after the nerve lesion. Here, we analyzed whether this neuroprotective effect is long-lasting and studied the impact of the pronounced RGC rescue on axonal regeneration. To this aim, we co-injected a GDNF- and a CNTF-overexpressing neural stem cell line into the vitreous cavity of adult mice one day after an optic nerve crush and determined the number of surviving RGCs 4, 6 and 8 months after the lesion. Remarkably, we found no significant decrease in the number of surviving RGCs between the successive analysis time points, indicating that the combined administration of GDNF and CNTF conferred lifelong protection to injured RGCs. While the simultaneous administration of GDNF and CNTF stimulated pronounced intraretinal axon growth when compared to retinas treated with either factor alone, numbers of regenerating axons in the distal optic nerve stumps were similar in animals co-treated with both factors and animals treated with CNTF only.
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10
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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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11
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Berry M, Ahmed Z, Logan A. Return of function after CNS axon regeneration: Lessons from injury-responsive intrinsically photosensitive and alpha retinal ganglion cells. Prog Retin Eye Res 2019; 71:57-67. [DOI: 10.1016/j.preteyeres.2018.11.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/26/2018] [Accepted: 11/16/2018] [Indexed: 12/16/2022]
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12
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Bray ER, Yungher BJ, Levay K, Ribeiro M, Dvoryanchikov G, Ayupe AC, Thakor K, Marks V, Randolph M, Danzi MC, Schmidt TM, Chaudhari N, Lemmon VP, Hattar S, Park KK. Thrombospondin-1 Mediates Axon Regeneration in Retinal Ganglion Cells. Neuron 2019; 103:642-657.e7. [PMID: 31255486 DOI: 10.1016/j.neuron.2019.05.044] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 02/11/2019] [Accepted: 05/28/2019] [Indexed: 12/20/2022]
Abstract
Neuronal subtypes show diverse injury responses, but the molecular underpinnings remain elusive. Using transgenic mice that allow reliable visualization of axonal fate, we demonstrate that intrinsically photosensitive retinal ganglion cells (ipRGCs) are both resilient to cell death and highly regenerative. Using RNA sequencing (RNA-seq), we show genes that are differentially expressed in ipRGCs and that associate with their survival and axon regeneration. Strikingly, thrombospondin-1 (Thbs1) ranked as the most differentially expressed gene, along with the well-documented injury-response genes Atf3 and Jun. THBS1 knockdown in RGCs eliminated axon regeneration. Conversely, RGC overexpression of THBS1 enhanced regeneration in both ipRGCs and non-ipRGCs, an effect that was dependent on syndecan-1, a known THBS1-binding protein. All structural domains of the THBS1 were not equally effective; the trimerization and C-terminal domains promoted regeneration, while the THBS type-1 repeats were dispensable. Our results identify cell-type-specific induction of Thbs1 as a novel gene conferring high regenerative capacity.
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Affiliation(s)
- Eric R Bray
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Benjamin J Yungher
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Konstantin Levay
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Marcio Ribeiro
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Gennady Dvoryanchikov
- Department of Physiology & Biophysics, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Ana C Ayupe
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Kinjal Thakor
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Victoria Marks
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Michael Randolph
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Matt C Danzi
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Tiffany M Schmidt
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Nirupa Chaudhari
- Department of Physiology & Biophysics, Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Vance P Lemmon
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Samer Hattar
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Kevin K Park
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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13
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Huang L, Xia B, Shi X, Gao J, Yang Y, Xu F, Qi F, Liang C, Huang J, Luo Z. Time-restricted release of multiple neurotrophic factors promotes axonal regeneration and functional recovery after peripheral nerve injury. FASEB J 2019; 33:8600-8613. [PMID: 30995417 DOI: 10.1096/fj.201802065rr] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Delivery of multiple neurotrophic factors (NTFs), especially with time-restricted release kinetics, holds great potential for nerve repair. In this study, we utilized the tetracycline-regulatable Tet-On 3G system to control the expression of c-Jun, which is a common regulator of multiple NTFs in Schwann cells (SCs). In vitro, Tet-On/c-Jun-modified SCs showed a tightly controllable secretion of multiple NTFs, including glial cell line-derived NTF, nerve growth factor, brain-derived NTF, and artemin, by the addition or removal of doxycycline (Dox). When Tet-On/c-Jun-transduced SCs were grafted in vivo, the expression of NTFs could also be regulated by oral administration or removal of Dox. Fluoro-Gold retrograde tracing results indicated that a biphasic NTF expression scheme (Dox+3/-9, NTFs were up-regulated for 3 wk and declined to physiologic levels for another 9 wk) achieved more axonal regeneration than continuous up-regulation of NTFs (Dox+12) or no NTF induction (Dox-12). More importantly, the Dox+3/-9-group animals showed much better functional recovery than the animals in the Dox+12 and Dox-12 groups. Our findings, for the first time, demonstrated drug-controllable expression of multiple NTFs in nerve repair cells both in vitro and in vivo. These findings provide new hope for developing an optimal therapeutic alternative for nerve repair through the time-restricted release of multiple NTFs using Tet-On/c-Jun-modified SCs.-Huang, L., Xia, B., Shi, X., Gao, J., Yang, Y., Xu, F., Qi, F., Liang, C., Huang, J., Luo, Z. Time-restricted release of multiple neurotrophic factors promotes axonal regeneration and functional recovery after peripheral nerve injury.
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Affiliation(s)
- Liangliang Huang
- Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.,Department of Orthopaedics, General Hospital of Central Theater Command of People's Liberation Army, Wuhan, China
| | - Bing Xia
- Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Xiaowei Shi
- Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Jianbo Gao
- Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Yujie Yang
- Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Feng Xu
- Department of Orthopaedics, General Hospital of Central Theater Command of People's Liberation Army, Wuhan, China
| | - Fengyu Qi
- Department of Orthopaedics, General Hospital of Central Theater Command of People's Liberation Army, Wuhan, China
| | - Chao Liang
- Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Jinghui Huang
- Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Zhuojing Luo
- Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
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Devoldere J, Peynshaert K, De Smedt SC, Remaut K. Müller cells as a target for retinal therapy. Drug Discov Today 2019; 24:1483-1498. [PMID: 30731239 DOI: 10.1016/j.drudis.2019.01.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 12/20/2018] [Accepted: 01/30/2019] [Indexed: 12/28/2022]
Abstract
Müller cells are specialized glial cells that span the entire retina from the vitreous cavity to the subretinal space. Their functional diversity and unique radial morphology render them particularly interesting targets for new therapeutic approaches. In this review, we reflect on various possibilities for selective Müller cell targeting and describe how some of their cellular mechanisms can be used for retinal neuroprotection. Intriguingly, cross-species investigation of their properties has revealed that Müller cells also have an essential role in retinal regeneration. Although many questions regarding this subject remain, it is clear that Müller cells have unique characteristics that make them suitable targets for the prevention and treatment of numerous retinal diseases.
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Affiliation(s)
- Joke Devoldere
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Karen Peynshaert
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium
| | - Stefaan C De Smedt
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Cancer Research Institute Ghent (CRIG), Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - Katrien Remaut
- Ghent Research Group on Nanomedicines, Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Cancer Research Institute Ghent (CRIG), Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium.
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15
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Laughter MR, Bardill JR, Ammar DA, Pena B, Calkins DJ, Park D. Injectable Neurotrophic Factor Delivery System Supporting Retinal Ganglion Cell Survival and Regeneration Following Optic Nerve Crush. ACS Biomater Sci Eng 2018; 4:3374-3383. [PMID: 31431919 PMCID: PMC6701853 DOI: 10.1021/acsbiomaterials.8b00803] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In general, neurons belonging to the central nervous system (CNS), such as retinal ganglion cells (RGCs), do not regenerate. Due to this, strategies have emerged aimed at protecting and regenerating these cells. Neurotrophic factor (NTF) supplementation has been a promising approach but is limited by length of delivery and delivery vehicle. For this study, we tested a polymeric delivery system (sulfonated reverse thermal gel or SRTG) engineered to deliver cilliary neurotrophic factor (CNTF), while also being injectable. A rat optic nerve crush (ONC) model was used to determine the neuroprotective and regenerative capacity of our system. The results demonstrate that one single intravitreal injection of SRTG-CNTF following ONC showed significant protection of RGC survival at both 1 and 2 week time points, when compared to the control groups. Furthermore, there was no significant difference in the RGC count between the eyes that received the SRTG-CNTF following ONC and a healthy control eye. Intravitreal injection of the polymer system also induced noticeable axon regeneration 500 μm downstream from the lesion site compared to all other control groups. There was a significant increase in Müller cell response in groups that received the SRTG-CNTF injection following optic nerve crush also indicative of a regenerative response. Finally, higher concentrations of CNTF released from SRTG-CNTF showed a protective effect on RGCs and Müller cell response at a longer time point (4 weeks). In conclusion, we were able to show a neuroprotective and regenerative effect of this polymer SRTG-CNTF delivery system and the viability for treatment of neurodegenerations.
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Affiliation(s)
- Melissa R. Laughter
- Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado 80045, United States
| | - James R. Bardill
- Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado 80045, United States
| | - David A. Ammar
- Department of Ophthalmology, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado 80045, United States
| | - Brisa Pena
- Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado 80045, United States
| | - David J. Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Daewon Park
- Department of Bioengineering, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado 80045, United States
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Cortical AAV-CNTF Gene Therapy Combined with Intraspinal Mesenchymal Precursor Cell Transplantation Promotes Functional and Morphological Outcomes after Spinal Cord Injury in Adult Rats. Neural Plast 2018; 2018:9828725. [PMID: 30245710 PMCID: PMC6139201 DOI: 10.1155/2018/9828725] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/18/2018] [Accepted: 05/21/2018] [Indexed: 12/11/2022] Open
Abstract
Ciliary neurotrophic factor (CNTF) promotes survival and enhances long-distance regeneration of injured axons in parts of the adult CNS. Here we tested whether CNTF gene therapy targeting corticospinal neurons (CSN) in motor-related regions of the cerebral cortex promotes plasticity and regrowth of axons projecting into the female adult F344 rat spinal cord after moderate thoracic (T10) contusion injury (SCI). Cortical neurons were transduced with a bicistronic adeno-associated viral vector (AAV1) expressing a secretory form of CNTF coupled to mCHERRY (AAV-CNTFmCherry) or with control AAV only (AAV-GFP) two weeks prior to SCI. In some animals, viable or nonviable F344 rat mesenchymal precursor cells (rMPCs) were injected into the lesion site two weeks after SCI to modulate the inhibitory environment. Treatment with AAV-CNTFmCherry, as well as with AAV-CNTFmCherry combined with rMPCs, yielded functional improvements over AAV-GFP alone, as assessed by open-field and Ladderwalk analyses. Cyst size was significantly reduced in the AAV-CNTFmCherry plus viable rMPC treatment group. Cortical injections of biotinylated dextran amine (BDA) revealed more BDA-stained axons rostral and alongside cysts in the AAV-CNTFmCherry versus AAV-GFP groups. After AAV-CNTFmCherry treatments, many sprouting mCherry-immunopositive axons were seen rostral to the SCI, and axons were also occasionally found caudal to the injury site. These data suggest that CNTF has the potential to enhance corticospinal repair by transducing parent CNS populations.
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Wang WJ, Jin W, Yang AH, Chen Z, Xing YQ. Protective effects of ciliary neurotrophic factor on the retinal ganglion cells by injure of hydrogen peroxide. Int J Ophthalmol 2018; 11:923-928. [PMID: 29977802 DOI: 10.18240/ijo.2018.06.05] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 11/22/2017] [Indexed: 12/11/2022] Open
Abstract
AIM To explore the effect of ciliary neurotrophic factor (CNTF) on retinal ganglion cell (RGC)-5 induced by hydrogen peroxide (H2O2). METHODS After cell adherence, RGC-5 culture medium was changed to contain different concentrations of H2O2 from 50 to 150 µmol/L at four time points (0.5, 1, 1.5 and 2h) to select the concentration and time point for H2O2 induced model. Two different ways of interventions for injured RGC-5 cells respectively were CNTF as an addition in the culture medium or recombinant lentiviral plasmid carrying CNTF gene transfecting bone mesenchymal stem cells (BMSCs) for co-culture with RGC-5. RESULTS Compared to the control group, H2O2 led to RGC-5 death closely associated with concentrations and action time of H2O2 and we chose 125 µmol/L and 2h to establish the H2O2-induced model. While CNTF inhibited the loss of RGC-5 cells obviously with a dose-dependent survival rate. Nevertheless two administration routes had different survival rate yet higher rate in recombinant lentiviral plasmid group but there were no statistically significant differences. CONCLUSION Both the two administration routes of CNTF have effects on RGC-5 cells induced by H2O2. If their own advantages were combined, there may be a better administration route.
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Affiliation(s)
- Wen-Jun Wang
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - Wei Jin
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - An-Huai Yang
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - Zhen Chen
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
| | - Yi-Qiao Xing
- Eye Center, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China
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18
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Huang ZR, Chen HY, Hu ZZ, Xie P, Liu QH. PTEN knockdown with the Y444F mutant AAV2 vector promotes axonal regeneration in the adult optic nerve. Neural Regen Res 2018; 13:135-144. [PMID: 29451218 PMCID: PMC5840979 DOI: 10.4103/1673-5374.224381] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The lack of axonal regeneration is the major cause of vision loss after optic nerve injury in adult mammals. Activating the PI3K/AKT/mTOR signaling pathway has been shown to enhance the intrinsic growth capacity of neurons and to facilitate axonal regeneration in the central nervous system after injury. The deletion of the mTOR negative regulator phosphatase and tensin homolog (PTEN) enhances regeneration of adult corticospinal neurons and ganglion cells. In the present study, we used a tyrosine-mutated (Y444F) AAV2 vector to efficiently express a short hairpin RNA (shRNA) for silencing PTEN expression in retinal ganglion cells. We evaluated cell survival and axonal regeneration in a rat model of optic nerve axotomy. The rats received an intravitreal injection of wildtype AAV2 or Y444F mutant AAV2 (both carrying shRNA to PTEN) 4 weeks before optic nerve axotomy. Compared with the wildtype AAV2 vector, the Y444F mutant AAV2 vector enhanced retinal ganglia cell survival and stimulated axonal regeneration to a greater extent 6 weeks after axotomy. Moreover, post-axotomy injection of the Y444F AAV2 vector expressing the shRNA to PTEN rescued ~19% of retinal ganglion cells and induced axons to regenerate near to the optic chiasm. Taken together, our results demonstrate that PTEN knockdown with the Y444F AAV2 vector promotes retinal ganglion cell survival and stimulates long-distance axonal regeneration after optic nerve axotomy. Therefore, the Y444F AAV2 vector might be a promising gene therapy tool for treating optic nerve injury.
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Affiliation(s)
- Zheng-Ru Huang
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, Nanjing; Department of Ophthalmology, the Second People's Hospital of Changshu, Changshu, Jiangsu Province, China
| | - Hai-Ying Chen
- Department of Ophthalmology, The Second People's Hospital of Changshu, Changshu, Jiangsu Province, China
| | - Zi-Zhong Hu
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Ping Xie
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Qing-Huai Liu
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
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19
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Bollaerts I, Veys L, Geeraerts E, Andries L, De Groef L, Buyens T, Salinas-Navarro M, Moons L, Van Hove I. Complementary research models and methods to study axonal regeneration in the vertebrate retinofugal system. Brain Struct Funct 2017; 223:545-567. [DOI: 10.1007/s00429-017-1571-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 11/15/2017] [Indexed: 01/18/2023]
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20
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Ghasemi M, Alizadeh E, Saei Arezoumand K, Fallahi Motlagh B, Zarghami N. Ciliary neurotrophic factor (CNTF) delivery to retina: an overview of current research advancements. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2017; 46:1694-1707. [PMID: 29065723 DOI: 10.1080/21691401.2017.1391820] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The intraocular administration of the ciliary neurotrophic factor (CNTF) has been found to attenuate the photoreceptor degeneration and preserve retinal functions in the animal research models of the inherited or induced retinal disease. Studies with the aim of CNTF transfer to the posterior segment inside the eye have been directed to determine the best method for its administration. An ideal delivery method would overcome the eye drug elimination mechanisms or barriers and provide the sustained release of the CNTF into retina in the safest fashion with the minimum harm to the quality of life. This review focuses on the present state of CNTF delivery to retina, also provides an overview of available technologies and their challenges.
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Affiliation(s)
- Maryam Ghasemi
- a The Umbilical Cord Stem Cell Research Center (UCSRC) , Tabriz University of Medical Sciences , Tabriz , Iran.,b Department of Medical Biotechnology, Faculty of Advanced Medical Sciences , Tabriz University of Medical Sciences , Tabriz , Iran
| | - Effat Alizadeh
- a The Umbilical Cord Stem Cell Research Center (UCSRC) , Tabriz University of Medical Sciences , Tabriz , Iran.,b Department of Medical Biotechnology, Faculty of Advanced Medical Sciences , Tabriz University of Medical Sciences , Tabriz , Iran
| | - Khatereh Saei Arezoumand
- b Department of Medical Biotechnology, Faculty of Advanced Medical Sciences , Tabriz University of Medical Sciences , Tabriz , Iran
| | | | - Nosratollah Zarghami
- a The Umbilical Cord Stem Cell Research Center (UCSRC) , Tabriz University of Medical Sciences , Tabriz , Iran.,b Department of Medical Biotechnology, Faculty of Advanced Medical Sciences , Tabriz University of Medical Sciences , Tabriz , Iran.,d Department of Clinical Biochemistry and Laboratory Medicine, Faculty of Medicine , Tabriz University of Medical Sciences , Tabriz , Iran
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21
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Yungher BJ, Ribeiro M, Park KK. Regenerative Responses and Axon Pathfinding of Retinal Ganglion Cells in Chronically Injured Mice. Invest Ophthalmol Vis Sci 2017; 58:1743-1750. [PMID: 28324115 PMCID: PMC5361588 DOI: 10.1167/iovs.16-19873] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Purpose Enhanced regeneration of retinal ganglion cell (RGC) axons can be achieved by modification of numerous neuronal-intrinsic factors. However, axon growth initiation and the pathfinding behavior of these axons after traumatic injury remain poorly understood outside of acute injury paradigms, despite the clinical relevance of more chronic settings. We therefore examined RGC axon regeneration following therapeutic delivery that is postponed until 2 months after optic nerve crush injury. Methods Optic nerve regeneration was induced by virally mediated (adeno-associated virus) ciliary neurotrophic factor (AAV-CNTF) administered either immediately or 56 days after optic nerve crush in wild-type or Bax knockout (KO) mice. Retinal ganglion nerve axon regeneration was assessed 21 and 56 days after viral injection. Immunohistochemical analysis of RGC injury signals and extrinsic factors in the optic nerve were also examined at 5 and 56 days post crush. Results In addition to sustained expression of injury response proteins in surviving RGCs, we observe axon regrowth in wild-type and apoptosis-deficient Bax KO mice following AAV-CNTF treatment. Fewer instances of aberrant axon growth are seen, at least in the area near the lesion site, in animals given treatment 56 days after crush injury compared to the animals given treatment immediately after injury. We also find evidence of long distance growth into a visual target in Bax KO mice despite postponed initiation of this regenerative program. Conclusions These studies provide evidence against an intrinsic critical period for RGC axon regeneration or degradation of injury signals. Regeneration results from Bax KO mice imply highly sustained regenerative capacity in RGCs, highlighting the importance of long-lasting neuroprotective strategies as well as of RGC axon guidance research in chronically injured animals.
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Affiliation(s)
- Benjamin J Yungher
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Márcio Ribeiro
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Kevin K Park
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, Florida, United States
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22
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Neuroinflammation as Fuel for Axonal Regeneration in the Injured Vertebrate Central Nervous System. Mediators Inflamm 2017; 2017:9478542. [PMID: 28203046 PMCID: PMC5288536 DOI: 10.1155/2017/9478542] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 12/05/2016] [Accepted: 12/25/2016] [Indexed: 01/19/2023] Open
Abstract
Damage to the central nervous system (CNS) is one of the leading causes of morbidity and mortality in elderly, as repair after lesions or neurodegenerative disease usually fails because of the limited capacity of CNS regeneration. The causes underlying this limited regenerative potential are multifactorial, but one critical aspect is neuroinflammation. Although classically considered as harmful, it is now becoming increasingly clear that inflammation can also promote regeneration, if the appropriate context is provided. Here, we review the current knowledge on how acute inflammation is intertwined with axonal regeneration, an important component of CNS repair. After optic nerve or spinal cord injury, inflammatory stimulation and/or modification greatly improve the regenerative outcome in rodents. Moreover, the hypothesis of a beneficial role of inflammation is further supported by evidence from adult zebrafish, which possess the remarkable capability to repair CNS lesions and even restore functionality. Lastly, we shed light on the impact of aging processes on the regenerative capacity in the CNS of mammals and zebrafish. As aging not only affects the CNS, but also the immune system, the regeneration potential is expected to further decline in aged individuals, an element that should definitely be considered in the search for novel therapeutic strategies.
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23
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Cen LP, Liang JJ, Chen JH, Harvey AR, Ng TK, Zhang M, Pang CP, Cui Q, Fan YM. AAV-mediated transfer of RhoA shRNA and CNTF promotes retinal ganglion cell survival and axon regeneration. Neuroscience 2016; 343:472-482. [PMID: 28017835 DOI: 10.1016/j.neuroscience.2016.12.027] [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] [Received: 04/30/2016] [Revised: 12/14/2016] [Accepted: 12/18/2016] [Indexed: 12/09/2022]
Abstract
The aim of the present study was to determine whether adeno-associated viral vector (AAV) mediated transfer of ciliary neurotrophic factor (CNTF) and RhoA shRNA has additive effects on promoting the survival and axon regeneration of retinal ganglion cells (RGCs) after optic nerve crush (ONC). Silencing effects of AAV-RhoA shRNA were confirmed by examining neurite outgrowth in PC12 cells, and by quantifying RhoA expression levels with western blotting. Young adult Fischer rats received an intravitreal injection of (i) saline, (ii) AAV green fluorescent protein (GFP), (iii) AAV-CNTF, (iv) AAV-RhoA shRNA, or (v) a combination of both AAV-CNTF and AAV-RhoA shRNA. Two weeks later, the ON was completely crushed. Three weeks after ONC, RGC survival was estimated by counting βIII-tubulin-positive neurons in retinal whole mounts. Axon regeneration was evaluated by counting GAP-43-positive axons in the crushed ON. It was found that AAV-RhoA shRNA decreased RhoA expression levels and promoted neurite outgrowth in vitro. In the ONC model, AAV-RhoA shRNA by itself had only weak beneficial effects on RGC axon regeneration. However, when combined with AAV-CNTF, AAV-RhoA shRNA significantly improved the therapeutic effect of AAV-CNTF on axon regeneration by nearly two fold, even though there was no significant change in RGC viability. In sum, this combination of vectors increases the regenerative response and can lead to more successful therapeutic outcomes following neurotrauma.
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Affiliation(s)
- Ling-Ping Cen
- Joint Shantou International Eye Center, Shantou University and The Chinese University of Hong Kong, Shantou, PR China.
| | - Jia-Jian Liang
- Joint Shantou International Eye Center, Shantou University and The Chinese University of Hong Kong, Shantou, PR China
| | - Jian-Huan Chen
- Joint Shantou International Eye Center, Shantou University and The Chinese University of Hong Kong, Shantou, PR China
| | - Alan R Harvey
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, WA, Australia
| | - Tsz Kin Ng
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, PR China
| | - Mingzhi Zhang
- Joint Shantou International Eye Center, Shantou University and The Chinese University of Hong Kong, Shantou, PR China
| | - Chi Pui Pang
- Joint Shantou International Eye Center, Shantou University and The Chinese University of Hong Kong, Shantou, PR China; Department of Ophthalmology and Visual Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, PR China
| | - Qi Cui
- Joint Shantou International Eye Center, Shantou University and The Chinese University of Hong Kong, Shantou, PR China; Department of Ophthalmology and Visual Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, PR China
| | - You-Ming Fan
- Joint Shantou International Eye Center, Shantou University and The Chinese University of Hong Kong, Shantou, PR China; Department of Neurology, Affiliated Hospital of Hubei University for Nationalities, Enshi, PR China.
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Significant changes in endogenous retinal gene expression assessed 1 year after a single intraocular injection of AAV-CNTF or AAV-BDNF. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2016; 3:16078. [PMID: 27933306 PMCID: PMC5142514 DOI: 10.1038/mtm.2016.78] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Revised: 09/27/2016] [Accepted: 10/12/2016] [Indexed: 12/17/2022]
Abstract
Use of viral vectors to deliver therapeutic genes to the central nervous system holds promise for the treatment of neurodegenerative diseases and neurotrauma. Adeno-associated viral (AAV) vectors encoding brain-derived neurotrophic factor (BDNF) or ciliary derived neurotrophic factor (CNTF) promote the viability and regeneration of injured adult rat retinal ganglion cells. However, these growth-inducing transgenes are driven by a constitutively active promoter, thus we examined whether long-term AAV-mediated secretion of BDNF or CNTF affected endogenous retinal gene expression. One year after the intravitreal injection of AAV-green fluorescent protein (GFP), bi-cistronic AAV-BDNF-GFP or AAV-CNTF-GFP, mRNA was extracted and analyzed using custom 96 well polymerase chain reaction arrays. Of 93 test genes, 56% showed significantly altered expression in AAV-BDNF-GFP and/or AAV-CNTF-GFP retinas compared with AAV-GFP controls. Of these genes, 73% showed differential expression in AAV-BDNF versus AAV-CNTF injected eyes. To focus on retinal ganglion cell changes, quantitative polymerase chain reaction was undertaken on mRNA (16 genes) obtained from fixed retinal sections in which the ganglion cell layer was enriched. The sign and extent of fold changes in ganglion cell layer gene expression differed markedly from whole retinal samples. Sustained and global alteration in endogenous mRNA expression after gene therapy should be factored into any interpretation of experimental/clinical outcomes, particularly when introducing factors into the central nervous system that require secretion to evoke functionality.
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You SW, Hellström M, Pollett MA, LeVaillant C, Moses C, Rigby PJ, Penrose M, Rodger J, Harvey AR. Large-scale reconstitution of a retina-to-brain pathway in adult rats using gene therapy and bridging grafts: An anatomical and behavioral analysis. Exp Neurol 2016; 279:197-211. [DOI: 10.1016/j.expneurol.2016.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/01/2016] [Accepted: 03/02/2016] [Indexed: 12/30/2022]
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26
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Boyd RF, Boye SL, Conlon TJ, Erger KE, Sledge DG, Langohr IM, Hauswirth WW, Komáromy AM, Boye SE, Petersen-Jones SM, Bartoe JT. Reduced retinal transduction and enhanced transgene-directed immunogenicity with intravitreal delivery of rAAV following posterior vitrectomy in dogs. Gene Ther 2016; 23:548-56. [PMID: 27052802 DOI: 10.1038/gt.2016.31] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 02/19/2016] [Accepted: 02/29/2016] [Indexed: 12/22/2022]
Abstract
Adeno-associated virus (AAV) vector-based gene therapy is a promising treatment strategy for delivery of neurotrophic transgenes to retinal ganglion cells (RGCs) in glaucoma patients. Retinal distribution of transgene expression following intravitreal injection (IVT) of AAV is variable in animal models and the vitreous humor may represent a barrier to initial vector penetration. The primary goal of our study was to investigate the effect of prior core vitrectomy with posterior hyaloid membrane peeling on pattern and efficiency of transduction of a capsid amino acid substituted AAV2 vector, carrying the green fluorescent protein (GFP) reporter transgene following IVT in dogs. When progressive intraocular inflammation developed starting 4 weeks post IVT, the study plan was modified to allow detailed characterization of the etiology as a secondary goal. Unexpectedly, surgical vitrectomy was found to significantly limit transduction, whereas in non-vitrectomized eyes transduction efficiency reached upwards to 37.3% of RGC layer cells. The developing retinitis was characterized by mononuclear cell infiltrates resulting from a delayed-type hypersensitivity reaction, which we suspect was directed at the GFP transgene. Our results, in a canine large animal model, support caution when considering surgical vitrectomy before IVT for retinal gene therapy in patients, as prior vitrectomy appears to significantly reduce transduction efficiency and may predispose the patient to development of vector-induced immune reactions.
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Affiliation(s)
- R F Boyd
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
| | - S L Boye
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA
| | - T J Conlon
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, USA
| | - K E Erger
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, USA
| | - D G Sledge
- Diagnostic Center for Population and Animal Health, Michigan State University, East Lansing, MI, USA
| | - I M Langohr
- Diagnostic Center for Population and Animal Health, Michigan State University, East Lansing, MI, USA
| | - W W Hauswirth
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA
| | - A M Komáromy
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
| | - S E Boye
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA
| | - S M Petersen-Jones
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
| | - J T Bartoe
- Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA
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Yungher BJ, Luo X, Salgueiro Y, Blackmore MG, Park KK. Viral vector-based improvement of optic nerve regeneration: characterization of individual axons' growth patterns and synaptogenesis in a visual target. Gene Ther 2015; 22:811-21. [PMID: 26005861 PMCID: PMC4600032 DOI: 10.1038/gt.2015.51] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 04/10/2015] [Accepted: 05/05/2015] [Indexed: 12/21/2022]
Abstract
Lack of axon growth ability in the central nervous system poses a major barrier to achieving functional connectivity after injury. Thus, a non-transgenic regenerative approach to reinnervating targets has important implications in clinical and research settings. Previous studies using knockout (KO) mice have demonstrated long distance axon regeneration. Using an optic nerve injury model, here we evaluate the efficacy of viral, RNAi and pharmacological approaches that target the PTEN and STAT3 pathways to improve long distance axon regeneration in wild type (WT) mice. Our data show that adeno-associated virus (AAV) expressing short hairpin RNA (shRNA) against PTEN (shPTEN) enhances retinal ganglion cell axon regeneration after crush injury. However, compared to the previous data in PTEN KO mice, AAV-shRNA results in a lesser degree of regeneration, likely due to incomplete gene silencing inherent to RNAi. In comparison, an extensive enhancement in regeneration is seen when AAV-shPTEN is coupled to AAV encoding ciliary neurotrophic factor (CNTF) and to a cyclic adenosine monophosphate (cAMP) analogue, allowing axons to travel long distances and reach their target. We apply whole tissue imaging that facilitates three-dimensional visualization of single regenerating axons and document heterogeneous terminal patterns in the targets. This shows that some axonal populations generate extensive arbors and make synapses with the target neurons. Collectively, we show a combinatorial viral RNAi and pharmacological strategy that improves long distance regeneration in WT animals and provide single fiber projection data that indicates a degree of preservation of target recognition.
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Affiliation(s)
- B J Yungher
- Miami Project to Cure Paralysis, Department of Neurosurgery, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - X Luo
- Miami Project to Cure Paralysis, Department of Neurosurgery, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Y Salgueiro
- Miami Project to Cure Paralysis, Department of Neurosurgery, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - M G Blackmore
- Department of Biomedical Sciences, Marquette University, Milwaukee, WI, USA
| | - K K Park
- Miami Project to Cure Paralysis, Department of Neurosurgery, University of Miami, Miller School of Medicine, Miami, FL, USA
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Mathews MK, Guo Y, Langenberg P, Bernstein SL. Ciliary neurotrophic factor (CNTF)-mediated ganglion cell survival in a rodent model of non-arteritic anterior ischaemic optic neuropathy (NAION). Br J Ophthalmol 2014; 99:133-7. [PMID: 25336580 DOI: 10.1136/bjophthalmol-2014-305969] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Ciliary neurotrophic factor (CNTF) has been shown to protect retinal ganglion cells (RGCs) in traumatic optic nerve injury. We sought to evaluate this neuroprotective effect of CNTF after an ischaemic event using rodent anterior ischaemic optic neuropathy (rAION), a mouse model of non-arteritic anterior ischaemic optic neuropathy (NAION). METHODS We induced rAION in Thy1-cyan fluorescent protein (CFP) transgenic mice by exposing the optic nerve to frequency doubled neodymium yttrium aluminium garnet laser pulses following intravenous rose bengal injection. One day after rAION induction, an intravitreal injection of 0.75 μg CNTF or vehicle (sham injection) was given. Animals were euthanised on day 15 after induction, tissues isolated and CFP cells in the RGC layer were counted using stereology in flat-mounted retina. The average number of CFP-positive (CFP+) cells was determined for each study group and the percentages of RGC loss were compared between the different groups. RESULTS Two weeks after rAION induction, significantly more (CFP+) cells were preserved in CNTF-treated eyes than in sham-injected controls. Sham-treated animals showed a 58% loss of CFP+ cells. In contrast, CFP+ cell density in CNTF-treated eyes decreased by only 10%, when compared with untreated control eyes. This increased survival was statistically significant (p<0.05). CONCLUSIONS CNTF exerts a neuroprotective effect in ischaemic optic nerve injury and promotes RGC survival, suggesting that CNTF may be effective in the clinical treatment of human NAION.
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Affiliation(s)
- Michaela K Mathews
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Yan Guo
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Patricia Langenberg
- Department of Epidemiology and Public Health, University of Maryland, Baltimore, Maryland, USA
| | - Steven L Bernstein
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Effects of a conventional photocoagulator and a 3-ns pulse laser on preconditioning responses and retinal ganglion cell survival after optic nerve crush. Exp Eye Res 2014; 127:77-90. [DOI: 10.1016/j.exer.2014.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 07/07/2014] [Accepted: 07/10/2014] [Indexed: 11/22/2022]
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Zhou L, Wang H, Luo J, Xiong K, Zeng L, Chen D, Huang J. Regulatory effects of inhibiting the activation of glial cells on retinal synaptic plasticity. Neural Regen Res 2014; 9:385-93. [PMID: 25206825 PMCID: PMC4146193 DOI: 10.4103/1673-5374.128240] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2014] [Indexed: 01/09/2023] Open
Abstract
Various retinal injuries induced by ocular hypertension have been shown to induce plastic changes in retinal synapses, but the potential regulatory mechanism of synaptic plasticity after retinal injury was still unclear. A rat model of acute ocular hypertension was established by injecting saline intravitreally for an hour, and elevating the intraocular pressure to 14.63 kPa (110 mmHg). Western blot assay and immunofluorescence results showed that synaptophysin expression had a distinct spatiotemporal change that increased in the inner plexiform layer within 1 day and spread across the outer plexiform layer after 3 days. Glial fibrillary acidic protein expression in retinae was greatly increased after 3 days, and reached a peak at 7 days, which was also consistent with the peak time of synaptophysin expression in the outer plexiform layer following the increased intraocular pressure. Fluorocitrate, a glial metabolic inhibitor, was intravitreally injected to inhibit glial cell activation following high intraocular pressure. This significantly inhibited the enhanced glial fibrillary acidic protein expression induced by high intraocular pressure injury. Synaptophysin expression also decreased in the inner plexiform layer within a day and the widened distribution in the outer plexiform layer had disappeared by 3 days. The results suggested that retinal glial cell activation might play an important role in the process of retinal synaptic plasticity induced by acute high intraocular pressure through affecting the expression and distribution of synaptic functional proteins, such as synaptophysin.
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Affiliation(s)
- Lihong Zhou
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha, Hunan Province, China
| | - Hui Wang
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha, Hunan Province, China
| | - Jia Luo
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha, Hunan Province, China
| | - Kun Xiong
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha, Hunan Province, China
| | - Leping Zeng
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha, Hunan Province, China
| | - Dan Chen
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha, Hunan Province, China
| | - Jufang Huang
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha, Hunan Province, China
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Cyclic AMP and the regeneration of retinal ganglion cell axons. Int J Biochem Cell Biol 2014; 56:66-73. [PMID: 24796847 DOI: 10.1016/j.biocel.2014.04.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/10/2014] [Accepted: 04/22/2014] [Indexed: 01/12/2023]
Abstract
In this paper we present a brief review of studies that have reported therapeutic benefits of elevated cAMP on plasticity and regeneration after injury to the central nervous system (CNS). We also provide new data on the cellular mechanisms by which elevation of cyclic adenosine monophosphate (cAMP) promotes cytokine driven regeneration of adult CNS axons, using the visual system as the experimental model. cAMP is a second messenger for many intracellular signalling pathways. Elevation of cAMP in the eye by intravitreal injection of the cell permeant analogue (8-(4-chlorophenylthio)-adenosine-3',5'-cyclic monophosphate; CPT-cAMP), when added to recombinant ciliary neurotrophic factor (rCNTF), significantly enhances rCNTF-induced regeneration of adult rat retinal ganglion cell (RGC) axons into peripheral nerve (PN) grafted onto transected optic nerve. This effect is mediated to some extent by protein kinase A (PKA) signalling, but CPT-cAMP also acts via PI3K/Akt signalling to reduce suppressor of cytokine signalling protein 3 (SOCS3) activity in RGCs. Another target for cAMP is the exchange protein activated by cAMP (Epac), which can also mediate cAMP-induced axonal growth. Here we describe some novel results and discuss to what extent the pro-regenerative effects of CPT-cAMP on adult RGCs are mediated via Epac as well as via PKA-dependent pathways. We used the established PN-optic nerve graft model and quantified the survival and regenerative growth of adult rat RGCs after intravitreal injection of rCNTF in combination with a selective activator of PKA and/or a specific activator of Epac. Viable RGCs were identified by βIII-tubulin immunohistochemistry and regenerating RGCs retrogradely labelled and quantified after an injection of fluorogold into the distal end of the PN grafts, 4 weeks post-transplantation. The specific agonists of either PKA or Epac were both effective in enhancing the effects of rCNTF on RGC axonal regeneration, but interestingly, injections that combined rCNTF with both agonists were significantly less effective. The results are discussed in relation to previous CPT-cAMP studies on RGCs, and we also consider the need to modulate cAMP levels in order to obtain the most functionally effective regenerative response after CNS trauma. This article is part of a directed issue entitled: Regenerative Medicine: the challenge of translation.
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Hanumunthadu D, Dehabadi MH, Cordeiro MF. Neuroprotection in glaucoma: current and emerging approaches. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/17469899.2014.892415] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Harvey AR. Gene therapy and the regeneration of retinal ganglion cell axons. Neural Regen Res 2014; 9:232-3. [PMID: 25206805 PMCID: PMC4146148 DOI: 10.4103/1673-5374.128213] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2014] [Indexed: 01/01/2023] Open
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Butt GF, Habib A, Mahgoub K, Sofela A, Tilley M, Guo L, Cordeiro MF. Optic nerve regeneration. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.12.66] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Weber AJ, Harman CD. BDNF treatment and extended recovery from optic nerve trauma in the cat. Invest Ophthalmol Vis Sci 2013; 54:6594-604. [PMID: 23989190 DOI: 10.1167/iovs.13-12683] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
PURPOSE We examined the treatment period necessary to restore retinal and visual stability following trauma to the optic nerve. METHODS Cats received unilateral optic nerve crush and no treatment (NT), treatment of the injured eye with brain-derived neurotrophic factor (BDNF), or treatment of the injured eye combined with treatment of visual cortex for 2 or 4 weeks. After 1-, 2-, 4-, or 6-week survival periods, pattern electroretinograms (PERGs) were obtained and retinal ganglion cell (RGC) survival determined. RESULTS In the peripheral retina, RGC survival for NT, eye only, and eye + cortex animals was 55%, 78%, and 92%, respectively, at 1 week, and 31%, 60%, and 93%, respectively, at 2 weeks. PERGs showed a similar pattern of improvement. After 4 weeks, RGC survival was 7%, 29%, and 53% in each group, with PERGs in the dual-treated animals similar to the 1- to 2-week animals. For area centralis (AC), the NT, eye only, and eye + cortex animals showed 47%, 78%, and 82% survival, respectively, at 2 weeks, and 13%, 54%, and 81% survival, respectively, at 4 weeks. Removing the pumps at 2 weeks resulted in ganglion cell survival levels of 76% and 74% in the AC at 4 and 6 weeks postcrush, respectively. The PERGs from 2-week treated, but 4- and 6-week survival animals were comparable to those of the 2-week animals. CONCLUSIONS Treating the entire central visual pathway is important following optic nerve trauma. Long-term preservation of central vision may be achieved with as little as 2 weeks of treatment using this approach.
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Affiliation(s)
- Arthur J Weber
- Department of Physiology, Neuroscience Training Program, Michigan State University, East Lansing, Michigan
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36
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Diekmann H, Fischer D. Glaucoma and optic nerve repair. Cell Tissue Res 2013; 353:327-37. [PMID: 23512141 DOI: 10.1007/s00441-013-1596-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 02/21/2013] [Indexed: 01/10/2023]
Abstract
Glaucoma is a leading cause of irreversible blindness worldwide and causes progressive visual impairment attributable to the dysfunction and death of retinal ganglion cells (RGCs). Progression of visual field damage is slow and typically painless. Thus, glaucoma is often diagnosed after a substantial percentage of RGCs has been damaged. To date, clinical interventions are mainly restricted to the reduction of intraocular pressure (IOP), one of the major risk factors for this disease. However, the lowering of IOP is often insufficient to halt or reverse the progress of visual loss, underlining the need for the development of alternative treatment strategies. Several lines of evidence suggest that axonal damage of RGCs occurs primary at the optic nerve head, where axons appear to be most vulnerable. Axonal injury leads to the functional loss of RGCs and subsequently induces the death of the neurons. However, the detailed molecular mechanism(s) underlying IOP-induced optic nerve injury remain poorly understood. Moreover, whether glaucoma pathophysiology is primarily axonal, glial, or vascular remains unclear. Therefore, protective strategies to prevent further axonal and subsequent soma degeneration are of great importance to limit the progression of sight loss. In addition, strategies that stimulate injured RGCs to regenerate and reconnect axons with their central targets are necessary for functional restoration. The present review provides an overview of the context of glaucoma pathogenesis and surveys recent findings regarding potential strategies for axonal regeneration of RGCs and optic nerve repair, focusing on the role of cytokines and their downstream signaling pathways.
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Affiliation(s)
- Heike Diekmann
- Department of Neurology, Experimental Neurology, Heinrich Heine University, Merowingerplatz 1a, 40225, Düsseldorf, Germany
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37
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Challenges in the development of glaucoma neuroprotection therapy. Cell Tissue Res 2013; 353:253-60. [DOI: 10.1007/s00441-013-1584-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 02/06/2013] [Indexed: 10/27/2022]
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Fischer D. Stimulating axonal regeneration of mature retinal ganglion cells and overcoming inhibitory signaling. Cell Tissue Res 2012; 349:79-85. [PMID: 22293973 DOI: 10.1007/s00441-011-1302-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 12/08/2011] [Indexed: 01/31/2023]
Abstract
Like other neurons of the central nervous system (CNS), retinal ganglion cells (RGCs) are normally unable to regenerate injured axons and instead undergo apoptotic cell death. This regenerative failure leads to lifelong visual deficits after optic nerve damage and is partially attributable to factors located in the inhibitory environment of the forming glial scar and myelin as well as to an insufficient intrinsic ability for axonal regrowth. In addition to its ophthalmological relevance, the optic nerve has long been used as a favorable paradigm for studying regenerative failure in the CNS as a whole. Findings over the last 15 years have shown that, under certain circumstances, mature RGCs can be transformed into an active regenerative state enabling these neurons to survive axotomy and to regenerate axons in the optic nerve. Moreover, combinatorial treatments overcoming the inhibitory environment of the glial scar and optic nerve myelin, together with approaches activating the intrinsic growth program, can further enhance the amount of regeneration in vivo. These findings are encouraging and open the possibility that clinically meaningful regenerationmay become achievable in the future.
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Affiliation(s)
- Dietmar Fischer
- Department of Neurology, Experimental Neurology, Heinrich Heine University Düsseldorf, Merowingerplatz 1a, 40225 Düsseldorf, Germany
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Saleh A, Roy Chowdhury SK, Smith DR, Balakrishnan S, Tessler L, Martens C, Morrow D, Schartner E, Frizzi KE, Calcutt NA, Fernyhough P. Ciliary neurotrophic factor activates NF-κB to enhance mitochondrial bioenergetics and prevent neuropathy in sensory neurons of streptozotocin-induced diabetic rodents. Neuropharmacology 2012; 65:65-73. [PMID: 23022047 DOI: 10.1016/j.neuropharm.2012.09.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 09/12/2012] [Accepted: 09/14/2012] [Indexed: 01/26/2023]
Abstract
Diabetes causes mitochondrial dysfunction in sensory neurons that may contribute to peripheral neuropathy. Ciliary neurotrophic factor (CNTF) promotes sensory neuron survival and axon regeneration and prevents axonal dwindling, nerve conduction deficits and thermal hypoalgesia in diabetic rats. In this study, we tested the hypothesis that CNTF protects sensory neuron function during diabetes through normalization of impaired mitochondrial bioenergetics. In addition, we investigated whether the NF-κB signal transduction pathway was mobilized by CNTF. Neurite outgrowth of sensory neurons derived from streptozotocin (STZ)-induced diabetic rats was reduced compared to neurons from control rats and exposure to CNTF for 24 h enhanced neurite outgrowth. CNTF also activated NF-κB, as assessed by Western blotting for the NF-κB p50 subunit and reporter assays for NF-κB promoter activity. Conversely, blockade of NF-κB signaling using SN50 peptide inhibited CNTF-mediated neurite outgrowth. Studies in mice with STZ-induced diabetes demonstrated that systemic therapy with CNTF prevented functional indices of peripheral neuropathy along with deficiencies in dorsal root ganglion (DRG) NF-κB p50 expression and DNA binding activity. DRG neurons derived from STZ-diabetic mice also exhibited deficiencies in maximal oxygen consumption rate and associated spare respiratory capacity that were corrected by exposure to CNTF for 24 h in an NF-κB-dependent manner. We propose that the ability of CNTF to enhance axon regeneration and protect peripheral nerve from structural and functional indices of diabetic peripheral neuropathy is associated with targeting of mitochondrial function, in part via NF-κB activation, and improvement of cellular bioenergetics.
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Affiliation(s)
- Ali Saleh
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB, Canada
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Receptor tyrosine kinases: molecular switches regulating CNS axon regeneration. JOURNAL OF SIGNAL TRANSDUCTION 2012; 2012:361721. [PMID: 22848811 PMCID: PMC3405719 DOI: 10.1155/2012/361721] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Accepted: 06/04/2012] [Indexed: 01/04/2023]
Abstract
The poor or lack of injured adult central nervous system (CNS) axon regeneration results in devastating consequences and poor functional recovery. The interplay between the intrinsic and extrinsic factors contributes to robust inhibition of axon regeneration of injured CNS neurons. The insufficient or lack of trophic support for injured neurons is considered as one of the major obstacles contributing to their failure to survive and regrow their axons after injury. In the CNS, many of the signalling pathways associated with neuronal survival and axon regeneration are regulated by several classes of receptor tyrosine kinases (RTK) that respond to a variety of ligands. This paper highlights and summarises the most relevant recent findings pertinent to different classes of the RTK family of molecules, with a particular focus on elucidating their role in CNS axon regeneration.
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41
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Fischer D, Leibinger M. Promoting optic nerve regeneration. Prog Retin Eye Res 2012; 31:688-701. [PMID: 22781340 DOI: 10.1016/j.preteyeres.2012.06.005] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Revised: 06/13/2012] [Accepted: 06/21/2012] [Indexed: 10/28/2022]
Abstract
Vision is the most important sense for humans and it is irreversibly impaired by axonal damage of retinal ganglion cells (RGCs) in the optic nerve due to the lack of axonal regeneration. The failure of regeneration is partially attributable to factors located in the inhibitory environment of the forming glial scar and myelin as well as an insufficient intrinsic ability for axonal regrowth. Moreover, RGCs undergo apoptotic cell death after optic nerve injury, eliminating any chance for regeneration. In this review, we discuss the different aspects that cause regenerative failure in the optic nerve. Moreover, we describe discoveries of the last two decades demonstrating that under certain circumstances mature RGCs can be transformed into an active regenerative state allowing these neurons to survive axotomy and to regenerate axons in the injured optic nerve. In this context we focus on the role of the cytokines ciliary neutrophic factor (CNTF) and leukemia inhibitory factor (LIF), their receptors and the downstream signaling pathways. Furthermore, we discuss strategies to overcome inhibitory signaling induced by molecules associated with optic nerve myelin and the glial scar as well as the regenerative outcome after combinatorial treatments. These findings are encouraging and may open the possibility that clinically meaningful regeneration may become achievable one day in the future.
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Affiliation(s)
- Dietmar Fischer
- Department of Neurology, Experimental Neurology, Heinrich Heine University Düsseldorf, Merowingerplatz 1a, 40225 Düsseldorf, Germany.
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42
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The molecular basis of retinal ganglion cell death in glaucoma. Prog Retin Eye Res 2012; 31:152-81. [DOI: 10.1016/j.preteyeres.2011.11.002] [Citation(s) in RCA: 565] [Impact Index Per Article: 47.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 10/28/2011] [Accepted: 11/01/2011] [Indexed: 12/14/2022]
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Rodger J, Drummond ES, Hellström M, Robertson D, Harvey AR. Long-term gene therapy causes transgene-specific changes in the morphology of regenerating retinal ganglion cells. PLoS One 2012; 7:e31061. [PMID: 22347429 PMCID: PMC3275572 DOI: 10.1371/journal.pone.0031061] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Accepted: 12/31/2011] [Indexed: 01/24/2023] Open
Abstract
Recombinant adeno-associated viral (rAAV) vectors can be used to introduce neurotrophic genes into injured CNS neurons, promoting survival and axonal regeneration. Gene therapy holds much promise for the treatment of neurotrauma and neurodegenerative diseases; however, neurotrophic factors are known to alter dendritic architecture, and thus we set out to determine whether such transgenes also change the morphology of transduced neurons. We compared changes in dendritic morphology of regenerating adult rat retinal ganglion cells (RGCs) after long-term transduction with rAAV2 encoding: (i) green fluorescent protein (GFP), or (ii) bi-cistronic vectors encoding GFP and ciliary neurotrophic factor (CNTF), brain-derived neurotrophic factor (BDNF) or growth-associated protein-43 (GAP43). To enhance regeneration, rats received an autologous peripheral nerve graft onto the cut optic nerve of each rAAV2 injected eye. After 5–8 months, RGCs with regenerated axons were retrogradely labeled with fluorogold (FG). Live retinal wholemounts were prepared and GFP positive (transduced) or GFP negative (non-transduced) RGCs injected iontophoretically with 2% lucifer yellow. Dendritic morphology was analyzed using Neurolucida software. Significant changes in dendritic architecture were found, in both transduced and non-transduced populations. Multivariate analysis revealed that transgenic BDNF increased dendritic field area whereas GAP43 increased dendritic complexity. CNTF decreased complexity but only in a subset of RGCs. Sholl analysis showed changes in dendritic branching in rAAV2-BDNF-GFP and rAAV2-CNTF-GFP groups and the proportion of FG positive RGCs with aberrant morphology tripled in these groups compared to controls. RGCs in all transgene groups displayed abnormal stratification. Thus in addition to promoting cell survival and axonal regeneration, vector-mediated expression of neurotrophic factors has measurable, gene-specific effects on the morphology of injured adult neurons. Such changes will likely alter the functional properties of neurons and may need to be considered when designing vector-based protocols for the treatment of neurotrauma and neurodegeneration.
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Affiliation(s)
- Jennifer Rodger
- Experimental and Regenerative Neuroscience, School of Animal Biology, The University of Western Australia, Perth, Australia
| | - Eleanor S. Drummond
- School of Anatomy and Human Biology, The University of Western Australia, Perth, Australia
| | - Mats Hellström
- School of Anatomy and Human Biology, The University of Western Australia, Perth, Australia
| | - Donald Robertson
- Discipline of Physiology, School of Biomedical and Biomolecular Sciences, The University of Western Australia, Perth, Australia
| | - Alan R. Harvey
- School of Anatomy and Human Biology, The University of Western Australia, Perth, Australia
- * E-mail:
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Neurotrophic factors and the regeneration of adult retinal ganglion cell axons. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2012; 106:1-33. [PMID: 23211458 DOI: 10.1016/b978-0-12-407178-0.00002-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The adult central nervous system (CNS) has only a limited capacity to regenerate axons after injury. This is due to a number of factors including the presence of extrinsic inhibitory factors that limit plasticity, lack of effective trophic support, and intrinsic changes in neuronal responsiveness. In this review, we describe the expression and role of neurotrophins in retinal ganglion cells (RGCs) during development and adulthood, and the receptors and miscellaneous signaling systems that influence axonal regeneration after injury. The impact of exogenous neurotrophic factors on adult RGCs injured at different sites in the visual pathway is described for several modes of delivery, including recombinant factors, viral vectors, cell transplantation, as well as combinatorial treatments involving other pharmacotherapeutic agents. Indirect, off-target effects of neurotrophic factors on RGC axonal regeneration are also considered. There remain unresolved issues relating to optimal delivery of neurotrophic factors, and we emphasize the need to develop safe, reliable methods for the regulation of exogenous supply of these factors to the injured CNS.
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Wen R, Tao W, Li Y, Sieving PA. CNTF and retina. Prog Retin Eye Res 2011; 31:136-51. [PMID: 22182585 DOI: 10.1016/j.preteyeres.2011.11.005] [Citation(s) in RCA: 156] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2011] [Revised: 10/29/2011] [Accepted: 11/17/2011] [Indexed: 11/15/2022]
Abstract
Ciliary neurotrophic factor (CNTF) is one of the most studied neurotrophic factors for neuroprotection of the retina. A large body of evidence demonstrates that CNTF promotes rod photoreceptor survival in almost all animal models. Recent studies indicate that CNTF also promotes cone photoreceptor survival and cone outer segment regeneration in the degenerating retina and improves cone function in dogs with congenital achromotopsia. In addition, CNTF is a neuroprotective factor and an axogenesis factor for retinal ganglion cells (RGCs). This review focuses on the effects of exogenous CNTF on photoreceptors and RGCs in the mammalian retina and the potential clinical application of CNTF for retinal degenerative diseases.
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Affiliation(s)
- Rong Wen
- Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
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