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Xia X, Shi C, Tsien C, Sun CB, Xie L, Luo Z, Bian M, Russano K, Thakur HS, Benowitz LI, Goldberg JL, Kapiloff MS. Ca 2+/Calmodulin-Dependent Protein Kinase II Enhances Retinal Ganglion Cell Survival But Suppresses Axon Regeneration after Optic Nerve Injury. eNeuro 2024; 11:ENEURO.0478-23.2024. [PMID: 38548335 PMCID: PMC10978821 DOI: 10.1523/eneuro.0478-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 03/01/2024] [Accepted: 03/05/2024] [Indexed: 04/01/2024] Open
Abstract
Neuroprotection after injury or in neurodegenerative disease remains a major goal for basic and translational neuroscience. Retinal ganglion cells (RGCs), the projection neurons of the eye, degenerate in optic neuropathies after axon injury, and there are no clinical therapies to prevent their loss or restore their connectivity to targets in the brain. Here we demonstrate a profound neuroprotective effect of the exogenous expression of various Ca2+/calmodulin-dependent protein kinase II (CaMKII) isoforms in mice. A dramatic increase in RGC survival following the optic nerve trauma was elicited by the expression of constitutively active variants of multiple CaMKII isoforms in RGCs using adeno-associated viral (AAV) vectors across a 100-fold range of AAV dosing in vivo. Despite this neuroprotection, however, short-distance RGC axon sprouting was suppressed by CaMKII, and long-distance axon regeneration elicited by several pro-axon growth treatments was likewise inhibited even as CaMKII further enhanced RGC survival. Notably, in a dose-escalation study, AAV-expressed CaMKII was more potent for axon growth suppression than the promotion of survival. That diffuse overexpression of constitutively active CaMKII strongly promotes RGC survival after axon injury may be clinically valuable for neuroprotection per se. However, the associated strong suppression of the optic nerve axon regeneration demonstrates the need for understanding the intracellular domain- and target-specific CaMKII activities to the development of CaMKII signaling pathway-directed strategies for the treatment of optic neuropathies.
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Affiliation(s)
- Xin Xia
- Department of Ophthalmology, Byers Eye Institute, Mary M. and Sash A. Spencer Center for Vision Research, Stanford University School of Medicine, Palo Alto, California 94034
| | - Caleb Shi
- Department of Neurosurgery, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts 02115
- Department of Neurosurgery and Ophthalmology, Harvard Medical School, Boston, Massachusetts 02115
| | - Christina Tsien
- Department of Ophthalmology, Byers Eye Institute, Mary M. and Sash A. Spencer Center for Vision Research, Stanford University School of Medicine, Palo Alto, California 94034
| | - Catalina B Sun
- Department of Ophthalmology, Byers Eye Institute, Mary M. and Sash A. Spencer Center for Vision Research, Stanford University School of Medicine, Palo Alto, California 94034
| | - Lili Xie
- Department of Neurosurgery, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts 02115
- Department of Neurosurgery and Ophthalmology, Harvard Medical School, Boston, Massachusetts 02115
| | - Ziming Luo
- Department of Ophthalmology, Byers Eye Institute, Mary M. and Sash A. Spencer Center for Vision Research, Stanford University School of Medicine, Palo Alto, California 94034
| | - Minjuan Bian
- Department of Ophthalmology, Byers Eye Institute, Mary M. and Sash A. Spencer Center for Vision Research, Stanford University School of Medicine, Palo Alto, California 94034
| | - Kristina Russano
- Department of Ophthalmology, Byers Eye Institute, Mary M. and Sash A. Spencer Center for Vision Research, Stanford University School of Medicine, Palo Alto, California 94034
| | - Hrishikesh Singh Thakur
- Department of Ophthalmology, Byers Eye Institute, Mary M. and Sash A. Spencer Center for Vision Research, Stanford University School of Medicine, Palo Alto, California 94034
| | - Larry I Benowitz
- Department of Neurosurgery, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts 02115
- Department of Neurosurgery and Ophthalmology, Harvard Medical School, Boston, Massachusetts 02115
| | - Jeffrey L Goldberg
- Department of Ophthalmology, Byers Eye Institute, Mary M. and Sash A. Spencer Center for Vision Research, Stanford University School of Medicine, Palo Alto, California 94034
| | - Michael S Kapiloff
- Department of Ophthalmology, Byers Eye Institute, Mary M. and Sash A. Spencer Center for Vision Research, Stanford University School of Medicine, Palo Alto, California 94034
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Strong TA, Esquivel J, Wang Q, Ledon PJ, Wang H, Gaidosh G, Tse D, Pelaez D. Activation of multiple Eph receptors on neuronal membranes correlates with the onset of optic neuropathy. EYE AND VISION (LONDON, ENGLAND) 2023; 10:42. [PMID: 37779186 PMCID: PMC10544557 DOI: 10.1186/s40662-023-00359-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 09/11/2023] [Indexed: 10/03/2023]
Abstract
BACKGROUND Optic neuropathy is a major cause of irreversible blindness, yet the molecular determinants that contribute to neuronal demise have not been fully elucidated. Several studies have identified 'ephrin signaling' as one of the most dysregulated pathways in the early pathophysiology of optic neuropathy with varied etiologies. Developmentally, gradients in ephrin signaling coordinate retinotopic mapping via repulsive modulation of cytoskeletal dynamics in neuronal membranes. Little is known about the role ephrin signaling plays in the post-natal visual system and its correlation with the onset of optic neuropathy. METHODS Postnatal mouse retinas were collected for mass spectrometry analysis for erythropoietin-producing human hepatocellular (Eph) receptors. Optic nerve crush (ONC) model was employed to induce optic neuropathy, and proteomic changes during the acute phase of neuropathic onset were analyzed. Confocal and super-resolution microscopy determined the cellular localization of activated Eph receptors after ONC injury. Eph receptor inhibitors assessed the neuroprotective effect of ephrin signaling modulation. RESULTS Mass spectrometry revealed expression of seven Eph receptors (EphA2, A4, A5, B1, B2, B3, and B6) in postnatal mouse retinal tissue. Immunoblotting analysis indicated a significant increase in phosphorylation of these Eph receptors 48 h after ONC. Confocal microscopy demonstrated the presence of both subclasses of Eph receptors within the retina. Stochastic optical reconstruction microscopy (STORM) super-resolution imaging combined with optimal transport colocalization analysis revealed a significant co-localization of activated Eph receptors with injured neuronal cells, compared to uninjured neuronal and/or injured glial cells, 48 h post-ONC. Eph receptor inhibitors displayed notable neuroprotective effects for retinal ganglion cells (RGCs) after six days of ONC injury. CONCLUSIONS Our findings demonstrate the functional presence of diverse Eph receptors in the postnatal mammalian retina, capable of modulating multiple biological processes. Pan-Eph receptor activation contributes to the onset of neuropathy in optic neuropathies, with preferential activation of Eph receptors on neuronal processes in the inner retina following optic nerve injury. Notably, Eph receptor activation precedes neuronal loss. We observed a neuroprotective effect on RGCs upon inhibiting Eph receptors. Our study highlights the importance of investigating this repulsive pathway in early optic neuropathies and provides a comprehensive characterization of the receptors present in the developed retina of mice, relevant to both homeostasis and disease processes.
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Affiliation(s)
- Thomas A Strong
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL, USA
- Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Avenue, Miami, FL, 33136, USA
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, USA
| | - Juan Esquivel
- Department of Physics, University of Florida College of Liberal Arts and Sciences, Gainesville, FL, USA
| | - Qikai Wang
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL, USA
- Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Avenue, Miami, FL, 33136, USA
| | - Paul J Ledon
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL, USA
- Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Avenue, Miami, FL, 33136, USA
- Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Hua Wang
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL, USA
- Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Avenue, Miami, FL, 33136, USA
| | - Gabriel Gaidosh
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA
| | - David Tse
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL, USA
- Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Avenue, Miami, FL, 33136, USA
| | - Daniel Pelaez
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL, USA.
- Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Avenue, Miami, FL, 33136, USA.
- Department of Biomedical Engineering, University of Miami College of Engineering, University of Miami, Coral Gables, FL, USA.
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, USA.
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA.
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Strong TA, Esquivel J, Wang Q, Ledon PJ, Wang H, Gaidosh G, Tse D, Pelaez D. Activation of Multiple Eph Receptors on Neuronal Membranes Correlates with The Onset of Traumatic Optic Neuropathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.05.543735. [PMID: 37333178 PMCID: PMC10274644 DOI: 10.1101/2023.06.05.543735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Background Optic neuropathy (ON) is a major cause of irreversible blindness, yet the molecular determinants that contribute to neuronal demise have not been fully elucidated. Several studies have identified 'ephrin signaling' as one of the most dysregulated pathways in the early pathophysiology of ON with varied etiologies. Developmentally, gradients in ephrin signaling coordinate retinotopic mapping via repulsive modulation of cytoskeletal dynamics in neuronal membranes. Little is known about the role ephrin signaling played in the post-natal visual system and its correlation with the onset of optic neuropathy. Methods Postnatal mouse retinas were collected for mass spectrometry analysis for Eph receptors. Optic nerve crush (ONC) model was employed to induce optic neuropathy, and proteomic changes during the acute phase of neuropathic onset were analyzed. Confocal and super-resolution microscopy determined the cellular localization of activated Eph receptors after ONC injury. Eph receptor inhibitors assessed the neuroprotective effect of ephrin signaling modulation. Results Mass spectrometry revealed expression of seven Eph receptors (EphA2, A4, A5, B1, B2, B3, and B6) in postnatal mouse retinal tissue. Immunoblotting analysis indicated a significant increase in phosphorylation of these Eph receptors 48 hours after ONC. Confocal microscopy demonstrated the presence of both subclasses of Eph receptors in the inner retinal layers. STORM super-resolution imaging combined with optimal transport colocalization analysis revealed a significant co-localization of activated Eph receptors with injured neuronal processes, compared to uninjured neuronal and/or injured glial cells, 48 hours post-ONC. Eph receptor inhibitors displayed notable neuroprotective effects after 6 days of ONC injury. Conclusions Our findings demonstrate the functional presence of diverse Eph receptors in the postnatal mammalian retina, capable of modulating multiple biological processes. Pan-Eph receptor activation contributes to the onset of neuropathy in ONs, with preferential activation of Eph receptors on neuronal processes in the inner retina following optic nerve injury. Notably, Eph receptor activation precedes neuronal loss. We observed neuroprotective effects upon inhibiting Eph receptors. Our study highlights the importance of investigating this repulsive pathway in early optic neuropathies and provides a comprehensive characterization of the receptors present in the developed retina of mice, relevant to both homeostasis and disease processes.
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Affiliation(s)
- Thomas A. Strong
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL, United States of America
- Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States of America
- Department of Cell Biology, University of Miami Miller School of Medicine
| | - Juan Esquivel
- Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Qikai Wang
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL, United States of America
- Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Paul J. Ledon
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL, United States of America
- Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Hua Wang
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL, United States of America
- Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Gabriel Gaidosh
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - David Tse
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL, United States of America
- Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States of America
| | - Daniel Pelaez
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, FL, United States of America
- Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States of America
- Department of Biomedical Engineering, University of Miami College of Engineering, University of Miami, Coral Gables, FL, United States of America
- Department of Cell Biology, University of Miami Miller School of Medicine
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, United States of America
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Human Pluripotent Stem Cell-Derived Neural Progenitor Cells Promote Retinal Ganglion Cell Survival and Axon Recovery in an Optic Nerve Compression Animal Model. Int J Mol Sci 2021; 22:ijms222212529. [PMID: 34830410 PMCID: PMC8622638 DOI: 10.3390/ijms222212529] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/14/2021] [Accepted: 11/17/2021] [Indexed: 11/24/2022] Open
Abstract
Human pluripotent stem cell-derived neural progenitor cells (NPCs) have the potential to recover from nerve injury. We previously reported that human placenta-derived mesenchymal stem cells (PSCs) have neuroprotective effects. To evaluate the potential benefit of NPCs, we compared them to PSCs using R28 cells under hypoxic conditions and a rat model of optic nerve injury. NPCs and PSCs (2 × 106 cells) were injected into the subtenon space. After 1, 2, and 4 weeks, we examined changes in target proteins in the retina and optic nerve. NPCs significantly induced vascular endothelial growth factor (Vegf) compared to age-matched shams and PSC groups at 2 weeks; they also induced neurofilaments in the retina compared to the sham group at 4 weeks. In addition, the expression of brain-derived neurotrophic factor (Bdnf) was high in the retina in the NPC group at 2 weeks, while expression in the optic nerve was high in both the NPC and PSC groups. The low expression of ionized calcium-binding adapter molecule 1 (Iba1) in the retina had recovered at 2 weeks after NPC injection and at 4 weeks after PSC injection. The expression of the inflammatory protein NLR family, pyrin domain containing 3 (Nlrp3) was significantly reduced at 1 week, and that of tumor necrosis factor-α (Tnf-α) in the optic nerves of the NPC group was lower at 2 weeks. Regarding retinal ganglion cells, the expressions of Brn3a and Tuj1 in the retina were enhanced in the NPC group compared to sham controls at 4 weeks. NPC injections increased Gap43 expression from 2 weeks and reduced Iba1 expression in the optic nerves during the recovery period. In addition, R28 cells exposed to hypoxic conditions showed increased cell survival when cocultured with NPCs compared to PSCs. Both Wnt/β-catenin signaling and increased Nf-ĸb could contribute to the rescue of damaged retinal ganglion cells via upregulation of neuroprotective factors, microglial engagement, and anti-inflammatory regulation by NPCs. This study suggests that NPCs could be useful for the cellular treatment of various optic neuropathies, together with cell therapy using mesenchymal stem cells.
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Huang T, Li H, Zhang S, Liu F, Wang D, Xu J. Nrn1 Overexpression Attenuates Retinal Ganglion Cell Apoptosis, Promotes Axonal Regeneration, and Improves Visual Function Following Optic Nerve Crush in Rats. J Mol Neurosci 2020; 71:66-79. [DOI: 10.1007/s12031-020-01627-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 06/08/2020] [Indexed: 12/20/2022]
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Yang SG, Li CP, Peng XQ, Teng ZQ, Liu CM, Zhou FQ. Strategies to Promote Long-Distance Optic Nerve Regeneration. Front Cell Neurosci 2020; 14:119. [PMID: 32477071 PMCID: PMC7240020 DOI: 10.3389/fncel.2020.00119] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 04/14/2020] [Indexed: 02/06/2023] Open
Abstract
Mammalian retinal ganglion cells (RGCs) in the central nervous system (CNS) often die after optic nerve injury and surviving RGCs fail to regenerate their axons, eventually resulting in irreversible vision loss. Manipulation of a diverse group of genes can significantly boost optic nerve regeneration of mature RGCs by reactivating developmental-like growth programs or suppressing growth inhibitory pathways. By injury of the vision pathway near their brain targets, a few studies have shown that regenerated RGC axons could form functional synapses with targeted neurons but exhibited poor neural conduction or partial functional recovery. Therefore, the functional restoration of eye-to-brain pathways remains a greatly challenging issue. Here, we review recent advances in long-distance optic nerve regeneration and the subsequent reconnecting to central targets. By summarizing our current strategies for promoting functional recovery, we hope to provide potential insights into future exploration in vision reformation after neural injuries.
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Affiliation(s)
- Shu-Guang Yang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Chang-Ping Li
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Xue-Qi Peng
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Zhao-Qian Teng
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Chang-Mei Liu
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Feng-Quan Zhou
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, United States.,The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
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Poyomtip T. Roles of Toll-Like Receptor 4 for Cellular Pathogenesis in Primary Open-Angle Glaucoma: A potential therapeutic strategy. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2019; 52:201-206. [DOI: 10.1016/j.jmii.2018.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 12/19/2018] [Indexed: 10/27/2022]
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Tse BC, Dvoriantchikova G, Tao W, Gallo RA, Lee JY, Pappas S, Brambilla R, Ivanov D, Tse DT, Pelaez D. Tumor Necrosis Factor Inhibition in the Acute Management of Traumatic Optic Neuropathy. Invest Ophthalmol Vis Sci 2019; 59:2905-2912. [PMID: 30025145 PMCID: PMC5989875 DOI: 10.1167/iovs.18-24431] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Purpose To determine the effectiveness of etanercept, a tumor necrosis factor (TNF) inhibitor, in conferring neuroprotection to retinal ganglion cells (RGCs) and improving visual outcomes after optic nerve trauma with either optic nerve crush (ONC) or sonication-induced traumatic optic neuropathy (SI-TON) in mice. Methods Mouse optic nerves were unilaterally subjected to ONC (n = 20) or SI-TON (n = 20). TNF expression was evaluated by using immunohistochemistry and quantitative RT-PCR (qRT-PCR) in optic nerves harvested 6 and 24 hours post ONC (n = 10) and SI-TON (n = 10). Mice in each injury group received daily subcutaneous injections of either etanercept (10 mg/kg of body weight; five mice) or vehicle (five mice) for 7 days. Pattern electroretinograms were performed on all mice at 1 and 2 weeks after injury. ONC mice were killed at 2 weeks after injury, while SI-TON mice were euthanized at 4 weeks after injury. Whole retina flat-mounts were used for RGC quantification. Results Immunohistochemistry and qRT-PCR showed upregulation of TNF protein and gene expression within 24 hours after injury. In both models, etanercept use immediately following optic nerve injury led to higher RGC survival when compared to controls, which was comparable between the two models (24.23% in ONC versus 20.42% in SI-TON). In both models, 1 and 2 weeks post injury, mice treated with etanercept had significantly higher a-wave amplitudes than untreated injured controls. Conclusions Treatment with etanercept significantly reduced retinal damage and improved visual function in both animal models of TON. These findings suggest that reducing TNF activity in injured optic nerves constitutes an effective therapeutic approach in an acute setting.
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Affiliation(s)
- Brian C Tse
- Department of Ophthalmology, Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, Miami, Florida, United States
| | - Galina Dvoriantchikova
- Department of Ophthalmology, Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, Miami, Florida, United States
| | - Wensi Tao
- Department of Ophthalmology, Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, Miami, Florida, United States
| | - Ryan A Gallo
- Department of Ophthalmology, Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, Miami, Florida, United States
| | - John Y Lee
- Department of Ophthalmology, Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, Miami, Florida, United States
| | - Steven Pappas
- Department of Ophthalmology, Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, Miami, Florida, United States
| | - Roberta Brambilla
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Dmitry Ivanov
- Department of Ophthalmology, Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, Miami, Florida, United States.,Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - David T Tse
- Department of Ophthalmology, Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, Miami, Florida, United States
| | - Daniel Pelaez
- Department of Ophthalmology, Dr. Nasser Al-Rashid Orbital Vision Research Center, Bascom Palmer Eye Institute, Miami, Florida, United States.,Department of Biomedical Engineering, University of Miami, Coral Gables, Florida, United States
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Garcia AL, Udeh A, Kalahasty K, Hackam AS. A growing field: The regulation of axonal regeneration by Wnt signaling. Neural Regen Res 2018; 13:43-52. [PMID: 29451203 PMCID: PMC5840987 DOI: 10.4103/1673-5374.224359] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The canonical Wnt/β-catenin pathway is a highly conserved signaling cascade that plays critical roles during embryogenesis. Wnt ligands regulate axonal extension, growth cone guidance and synaptogenesis throughout the developing central nervous system (CNS). Recently, studies in mammalian and fish model systems have demonstrated that Wnt/β-catenin signaling also promotes axonal regeneration in the adult optic nerve and spinal cord after injury, raising the possibility that Wnt could be developed as a therapeutic strategy. In this review, we summarize experimental evidence that reveals novel roles for Wnt signaling in the injured CNS, and discuss possible mechanisms by which Wnt ligands could overcome molecular barriers inhibiting axonal growth to promote regeneration. A central challenge in the neuroscience field is developing therapeutic strategies that induce robust axonal regeneration. Although adult axons have the capacity to respond to axonal guidance molecules after injury, there are several major obstacles for axonal growth, including extensive neuronal death, glial scars at the injury site, and lack of axonal guidance signals. Research in rodents demonstrated that activation of Wnt/β-catenin signaling in retinal neurons and radial glia induced neuronal survival and axonal growth, but that activation within reactive glia at the injury site promoted proliferation and glial scar formation. Studies in zebrafish spinal cord injury models confirm an axonal regenerative role for Wnt/β-catenin signaling and identified the cell types responsible. Additionally, in vitro and in vivo studies demonstrated that Wnt induces axonal and neurite growth through transcription-dependent effects of its central mediator β-catenin, potentially by inducing regeneration-promoting genes. Canonical Wnt signaling may also function through transcription-independent interactions of β-catenin with cytoskeletal elements, which could stabilize growing axons and control growth cone movement. Therefore, these studies suggest that Wnt-induced pathways responsible for regulating axonal growth during embryogenesis could be repurposed to promote axonal growth after injury.
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Affiliation(s)
- Armando L Garcia
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Adanna Udeh
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Karthik Kalahasty
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Abigail S Hackam
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
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