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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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2
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Neuroprotective Strategies for Retinal Ganglion Cell Degeneration: Current Status and Challenges Ahead. Int J Mol Sci 2020; 21:ijms21072262. [PMID: 32218163 PMCID: PMC7177277 DOI: 10.3390/ijms21072262] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 12/12/2022] Open
Abstract
The retinal ganglion cells (RGCs) are the output cells of the retina into the brain. In mammals, these cells are not able to regenerate their axons after optic nerve injury, leaving the patients with optic neuropathies with permanent visual loss. An effective RGCs-directed therapy could provide a beneficial effect to prevent the progression of the disease. Axonal injury leads to the functional loss of RGCs and subsequently induces neuronal death, and axonal regeneration would be essential to restore the neuronal connectivity, and to reestablish the function of the visual system. The manipulation of several intrinsic and extrinsic factors has been proposed in order to stimulate axonal regeneration and functional repairing of axonal connections in the visual pathway. However, there is a missing point in the process since, until now, there is no therapeutic strategy directed to promote axonal regeneration of RGCs as a therapeutic approach for optic neuropathies.
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3
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Abstract
Afferent and efferent nerve fibers cannot be distinguished based on the axonal diameter or the presence of the Remark bundle. The compaction of the myelin sheath involves 2 steps: 1) The distance between the 2 layers of cell membranes in the double-bilayer decreases; 2) the adjacent double-bilayers close to form MDL. The expression of MBP is positively correlated with the formation of the MDL. Anchoring of the myelin sheath by lipophilin particles might be required for the formation of a compacted myelin sheath. The abnormalities in nerve fiber structure observed in autologous nerve grafts do not appear to be related to either MBP or lipophilin, so further research is needed to determine their causes. Observing the structure and regeneration of the myelin sheath in peripheral nerves following injury and during repair would help in understanding the pathogenesis and treatment of neurological diseases caused by an abnormal myelin sheath. In the present study, transmission electron microscopy, immunofluorescence staining, and transcriptome analyses were used to investigate the structure and regeneration of the myelin sheath after end-to-end anastomosis, autologous nerve transplantation, and nerve tube transplantation in a rat model of sciatic nerve injury, with normal optic nerve, oculomotor nerve, sciatic nerve, and Schwann cells used as controls. The results suggested that the double-bilayer was the structural unit that constituted the myelin sheath. The major feature during regeneration was the compaction of the myelin sheath, wherein the distance between the 2 layers of cell membrane in the double-bilayer became shorter and the adjacent double-bilayers tightly closed together and formed the major dense line. The expression level of myelin basic protein was positively correlated with the formation of the major dense line, and the compacted myelin sheath could not be formed without the anchoring of the lipophilin particles to the myelin sheath.
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Galvao J, Iwao K, Apara A, Wang Y, Ashouri M, Shah TN, Blackmore M, Kunzevitzky NJ, Moore DL, Goldberg JL. The Krüppel-Like Factor Gene Target Dusp14 Regulates Axon Growth and Regeneration. Invest Ophthalmol Vis Sci 2019; 59:2736-2747. [PMID: 29860460 PMCID: PMC5983061 DOI: 10.1167/iovs.17-23319] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Purpose Adult central nervous system (CNS) neurons are unable to regenerate their axons after injury. Krüppel-like transcription factor (KLF) family members regulate intrinsic axon growth ability in vitro and in vivo, but mechanisms downstream of these transcription factors are not known. Methods Purified retinal ganglion cells (RGCs) were transduced to express exogenous KLF9, KLF16, KLF7, or KLF11; microarray analysis was used to identify downstream genes, which were screened for effects on axon growth. Dual-specificity phosphatase 14 (Dusp14) was further studied using genetic (siRNA, shRNA) and pharmacologic (PTP inhibitor IV) manipulation to assess effects on neurite length in vitro and survival and regeneration in vivo after optic nerve crush in rats and mice. Results By screening genes regulated by KLFs in RGCs, we identified Dusp14 as a critical gene target limiting axon growth and regeneration downstream of KLF9's ability to suppress axon growth in RGCs. The KLF9-Dusp14 pathway inhibited activation of mitogen-activated protein kinases normally critical to neurotrophic signaling of RGC survival and axon elongation. Decreasing Dusp14 expression or disrupting its function in RGCs increased axon growth in vitro and promoted survival and optic nerve regeneration after optic nerve injury in vivo. Conclusions These results link intrinsic and extrinsic regulators of axon growth and suggest modulation of the KLF9-Dusp14 pathway as a potential approach to improve regeneration in the adult CNS after injury.
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Affiliation(s)
- Joana Galvao
- Byers Eye Institute, Stanford University, Palo Alto, California, United States.,Shiley Eye Center, University of California San Diego, La Jolla, California, United States
| | - Keiichiro Iwao
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Akintomide Apara
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Yan Wang
- Shiley Eye Center, University of California San Diego, La Jolla, California, United States.,Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Masoumeh Ashouri
- Shiley Eye Center, University of California San Diego, La Jolla, California, United States
| | - Tejas Nimish Shah
- Shiley Eye Center, University of California San Diego, La Jolla, California, United States
| | - Murray Blackmore
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Noelia J Kunzevitzky
- Byers Eye Institute, Stanford University, Palo Alto, California, United States.,Shiley Eye Center, University of California San Diego, La Jolla, California, United States.,Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States.,Center for Computational Science, University of Miami, Miami, Florida, United States
| | - Darcie L Moore
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Jeffrey L Goldberg
- Byers Eye Institute, Stanford University, Palo Alto, California, United States.,Shiley Eye Center, University of California San Diego, La Jolla, California, United States.,Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
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5
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Abstract
Retinal ganglion cells (RGCs) undergo programmed cell death (apoptosis) after axonal injury. This cell death is mediated by several mechanisms, including deprivation of neurotrophic factors, alterations in gene expression, and production of reactive oxygen species. However, death of RGCs is delayed after axonal injury, and a significant number survive even after several days. This suggests that RGC death is not an immediate result of axonal injury, and that other pro-survival factors may play a role. While we and other researchers have focused on the mechanisms of cell death after axonal injury, it may be that determining the regulation of cell survival mechanisms may lead to innovative methods for neuroprotection. The final common pathway of glaucomatous optic neuropathy is RGC death, probably via damage to their axons occurring at or near the lamina cribrosa. Axonal injury leads directly (1) or indirectly (2) to the death of retinal ganglion cells. We and others have demonstrated that axotomy is associated with RGC apoptosis (3-7) as well as specific changes in expression of certain genes at the mRNA and protein level (8, 9). Reactive oxygen species may also be part of the pathway for RGC death (10, 11). We therefore hypothesize that axotomy leads to molecular events that are potentially destructive to RGCs, but also induces changes that are potentially protective against cellular injury. If this is the case, then RGC death from axonal injury would result not only from initiation of apoptosis, but also from failure of intrinsic neuroprotective mechanisms. It should therefore be theoretically possible to modulate these two classes of responses, and thus improve RGC cell survival after axotomy.
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Affiliation(s)
- L A Levin
- Department of Ophthalmology and Visual Sciences, University of Wisconsin Medical School, Madison, USA.
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Cen LP, Ng TK, Liang JJ, Zhuang X, Yao X, Yam GHF, Chen H, Cheung HS, Zhang M, Pang CP. Human Periodontal Ligament-Derived Stem Cells Promote Retinal Ganglion Cell Survival and Axon Regeneration After Optic Nerve Injury. Stem Cells 2018; 36:844-855. [PMID: 29476565 DOI: 10.1002/stem.2812] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 02/06/2018] [Accepted: 02/12/2018] [Indexed: 02/05/2023]
Abstract
Optic neuropathies are the leading cause of irreversible blindness and visual impairment in the developed countries, affecting more than 80 million people worldwide. While most optic neuropathies have no effective treatment, there is intensive research on retinal ganglion cell (RGC) protection and axon regeneration. We previously demonstrated potential of human periodontal ligament-derived stem cells (PDLSCs) for retinal cell replacement. Here, we report the neuroprotective effect of human PDLSCs to ameliorate RGC degeneration and promote axonal regeneration after optic nerve crush (ONC) injury. Human PDLSCs were intravitreally injected into the vitreous chamber of adult Fischer rats after ONC in vivo as well as cocultured with retinal explants in vitro. Human PDLSCs survived in the vitreous chamber and were maintained on the RGC layer even at 3 weeks after ONC. Immunofluorescence analysis of βIII-tubulin and Gap43 showed that the numbers of surviving RGCs and regenerating axons were significantly increased in the rats with human PDLSC transplantation. In vitro coculture experiments confirmed that PDLSCs enhanced RGC survival and neurite regeneration in retinal explants without inducing inflammatory responses. Direct cell-cell interaction and elevated brain-derived neurotrophic factor secretion, but not promoting endogenous progenitor cell regeneration, were the RGC protective mechanisms of human PDLSCs. In summary, our results revealed the neuroprotective role of human PDLSCs by strongly promoting RGC survival and axonal regeneration both in vivo and in vitro, indicating a therapeutic potential for RGC protection against optic neuropathies. Stem Cells 2018;36:844-855.
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Affiliation(s)
- Ling-Ping Cen
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, People's Republic of China
| | - Tsz Kin Ng
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, People's Republic of China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Sha Tin, Hong Kong
| | - Jia-Jian Liang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, People's Republic of China
| | - Xi Zhuang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, People's Republic of China
| | - Xiaowu Yao
- Dentistry Department, Second Affiliated Hospital, Shantou University Medical College, Shantou, People's Republic of China
| | - Gary Hin-Fai Yam
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Sha Tin, Hong Kong
| | - Haoyu Chen
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, People's Republic of China
| | - Herman S Cheung
- Department of Biomedical Engineering, College of Engineering, University of Miami, Coral Gables, Florida, USA
| | - Mingzhi Zhang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, People's Republic of China
| | - Chi Pui Pang
- Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, People's Republic of China
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Sha Tin, Hong Kong
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7
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NGF protects corneal, retinal, and cutaneous tissues/cells from phototoxic effect of UV exposure. Graefes Arch Clin Exp Ophthalmol 2018; 256:729-738. [DOI: 10.1007/s00417-018-3931-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 12/30/2017] [Accepted: 02/02/2018] [Indexed: 01/25/2023] Open
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8
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Konobu T, Sessler F, Luo LY, Lehmann J. The hNT Human Neuronal Cell Line Survives and Migrates into Rat Retina. Cell Transplant 2017; 7:549-58. [PMID: 9853583 DOI: 10.1177/096368979800700605] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The present studies were undertaken to determine if hNT cells can survive in the vitreous of the eye and migrate into the retina. The hNT neuronal cell line represents a uniform source of human tissue that may be of use in retinal grafts. hNT cells stored in liquid nitrogen were thawed and labeled with the fluorescent dye 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine Perchlorate (DiI). Thirty thousand cells in 1 μL were injected epiretinally in rat. At survival times of 3, 14, 28, or 56 days, retinal sections were examined quantitatively by epifluorescence to reveal DiI-labeled cells. hNT cells survived in the vitreous at all time points without evidence of vascularization. At 3 days, essentially no hNT cells were found in deep retina, and only very few were attached to retina. At days 14, 28, and 56, hNT cells were found to cluster on the vitreal/retinal interface, and in deeper layers. The clusters of hNT cells took on the shape of a funnel at 14 days, and inverted funnel at 28 days, and by 56 days, populated the photoreceptor layer as a stratum. It is possible that hNT cells took on the morphology and function of photoreceptors. These results suggest that hNT cells injected epiretinally survive in the vitreous at least 56 days, migrate to the retinal/vitreous interface, and may migrate through the retina. This system permits the independent and quantitative evaluation of survival and migratory trophic responses. © 1998 Elsevier Science Inc.
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Affiliation(s)
- T Konobu
- Department of Neurosurgery, Allegheny University of the Health Sciences, Philadelphia, PA 19102-1192, USA
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9
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Renno WM, Khan KM, Benov L. Is there a role for neurotrophic factors and their receptors in augmenting the neuroprotective effect of (-)-epigallocatechin-3-gallate treatment of sciatic nerve crush injury? Neuropharmacology 2015; 102:1-20. [PMID: 26514400 DOI: 10.1016/j.neuropharm.2015.10.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 10/01/2015] [Accepted: 10/23/2015] [Indexed: 12/17/2022]
Abstract
This study analyzed and compared the effects of EGCG treatment on the expression of NTFs and NTF receptors expression in the sciatic nerve and the L3-L6 spinal cord segments at the early phase of regeneration following sciatic nerve crush injury. Analysis of BDNF, GDNF and NT3 neurotropic factors and Trk-B, Trk-C and NGFR-p75 receptors in neurons in the spinal cord of CRUSH and CRUSH + EGGC rats showed significant (p < 0.0001) decrease compared to NAÏVE and SHAM at day 1, 3, 7 and 14 after nerve injury. EGCG treatment significantly (p < 0.0001) increased the BDNF, GDN, NT3, Trk-B, Trk-C and NGFR-p75 immunostaining in the L3-L6 spinal cord compared to CRUSH animals. Also, EGCG treatment significantly increased the Trk-B protein concentration and Trk-B, NT3 and Trk-C gene expression in the spinal cords compared to CRUSH group. However, at day 1 and 3 post nerve injury, EGCG treatment significantly decreased the NGFR-p75 expression compared to CRUSH rats. In the sciatic nerve, EGCG treatment significantly (p < 0.01) increased the Trk-B and NGFR-p75 protein concentration in the controls. EGCG treatment significantly (p < 0.0001) increased the Trk-B, Trk-C and NGFR-p75 mRNA gene expressions in the sciatic nerves compared to CRUSH group. Only at day 1, CRUSH + EGCG animals displayed significant rise in the sciatic nerves NT3 gene expression compared to CRUSH group. Our data suggest that the EGCG neuroprotective effect on the spinal cord neurons may be mediated through the modulation of NTFs and NTF receptors following nerve crush injury in a rat model.
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Affiliation(s)
- Waleed M Renno
- Department of Anatomy, Faculty of Medicine, Kuwait University, Kuwait.
| | - Khalid M Khan
- Department of Anatomy, Faculty of Medicine, Kuwait University, Kuwait
| | - Ludmil Benov
- Department of Biochemistry, Faculty of Medicine, Kuwait University, Kuwait
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10
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Direct optic nerve sheath (DONS) application of Schwann cells prolongs retinal ganglion cell survival in vivo. Cell Death Dis 2014; 5:e1460. [PMID: 25321467 PMCID: PMC4237238 DOI: 10.1038/cddis.2014.399] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 08/06/2014] [Accepted: 08/08/2014] [Indexed: 01/10/2023]
Abstract
Cell-based therapies are increasingly recognized as a potential strategy to treat retinal neurodegenerative disease. Their administration, however, is normally indirect and complex, often with an inability to assess in real time their effects on cell death and their migration/integration into the host retina. In the present study, using a partial optic nerve transection (pONT) rat model, we describe a new method of Schwann cell (SC) delivery (direct application to injured optic nerve sheath, SC/DONS), which was compared with intravitreal SC delivery (SC/IVT). Both SC/DONS and SC/IVT were able to be assessed in vivo using imaging to visualize retinal ganglion cell (RGC) apoptosis and SC retinal integration. RGC death in the pONT model was best fitted to the one-phase exponential decay model. Although both SC/DONS and SC/IVT altered the temporal course of RGC degeneration in pONT, SC/DONS resulted in delayed but long-lasting effects on RGC protection, compared with SC/IVT treatment. In addition, their effects on primary and secondary degeneration, and axonal regeneration, were also investigated, by histology, whole retinal counting, and modelling of RGC loss. SC/DONS was found to significantly reduce RGC apoptosis in vivo and significantly increase RGC survival by targeting secondary rather than primary degeneration. Both SC/DONS and SC/IVT were found to promote RGC axonal regrowth after optic nerve injury, with evidence of GAP-43 expression in RGC somas and axons. SC/DONS may have the potential in the treatment of optic neuropathies, such as glaucoma. We show that SC transplantation can be monitored in real time and that the protective effects of SCs are associated with targeting secondary degeneration, with implications for translating cell-based therapies to the clinic.
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11
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Zhao F, He W, Zhang Y, Tian D, Zhao H, Yu K, Bai J. Electric stimulation and decimeter wave therapy improve the recovery of injured sciatic nerves. Neural Regen Res 2014; 8:1974-84. [PMID: 25206506 PMCID: PMC4145900 DOI: 10.3969/j.issn.1673-5374.2013.21.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 06/24/2013] [Indexed: 01/08/2023] Open
Abstract
Drug treatment, electric stimulation and decimeter wave therapy have been shown to promote the repair and regeneration of the peripheral nerves at the injured site. This study prepared a Mackinnon's model of rat sciatic nerve compression. Electric stimulation was given immediately after neurolysis, and decimeter wave radiation was performed at 1 and 12 weeks post-operation. Histological observation revealed that intraoperative electric stimulation and decimeter wave therapy could improve the local blood circulation of repaired sites, alleviate hypoxia of compressed nerves, and lessen adhesion of compressed nerves, thereby decreasing the formation of new entrapments and enhancing compressed nerve regeneration through an improved microenvironment for regeneration. Immunohistochemical staining results revealed that intraoperative electric stimulation and decimeter wave could promote the expression of S-100 protein. Motor nerve conduction velocity and amplitude, the number and diameter of myelinated nerve fibers, and sciatic functional index were significantly increased in the treated rats. These results verified that intraoperative electric stimulation and decimeter wave therapy contributed to the regeneration and the recovery of the functions in the compressed nerves.
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Affiliation(s)
- Feng Zhao
- Department of Orthopedics, the First Hospital of Hebei Medical University, Shijiazhuang 050031, Hebei Province, China
| | - Wei He
- Department of Hand Surgery, the Third Hospital of Hebei Medical University, Shijiazhuang 050051, Hebei Province, China
| | - Yingze Zhang
- Department of Hand Surgery, the Third Hospital of Hebei Medical University, Shijiazhuang 050051, Hebei Province, China
| | - Dehu Tian
- Department of Hand Surgery, the Third Hospital of Hebei Medical University, Shijiazhuang 050051, Hebei Province, China
| | - Hongfang Zhao
- Department of Hand Surgery, the Third Hospital of Hebei Medical University, Shijiazhuang 050051, Hebei Province, China
| | - Kunlun Yu
- Department of Hand Surgery, the Third Hospital of Hebei Medical University, Shijiazhuang 050051, Hebei Province, China
| | - Jiangbo Bai
- Department of Hand Surgery, the Third Hospital of Hebei Medical University, Shijiazhuang 050051, Hebei Province, China
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12
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Prokosch V, Chiwitt C, Rose K, Thanos S. Deciphering proteins and their functions in the regenerating retina. Expert Rev Proteomics 2014; 7:775-95. [DOI: 10.1586/epr.10.47] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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13
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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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14
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Ohnishi YI, Iwatsuki K, Shinzawa K, Ishihara M, Moriwaki T, Umegaki M, Kishima H, Yoshimine T. Adult olfactory sphere cells are a source of oligodendrocyte and Schwann cell progenitors. Stem Cell Res 2013; 11:1178-90. [PMID: 24012985 DOI: 10.1016/j.scr.2013.08.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 07/08/2013] [Accepted: 08/05/2013] [Indexed: 11/19/2022] Open
Abstract
The olfactory epithelial layer contains multipotent horizontal basal cells (HBCs) that differentiate into olfactory sensory neurons. Here, we show that rat HBCs express oligodendrocyte progenitor cell (OPC) and astrocyte markers. We generated olfactory sphere (OS) cells in cultures that were derived from adult rat olfactory mucosa. Fluorescence-activated cell sorting and immunofluorescence analyses showed that OS cells also express OPC and astrocyte markers. Interestingly, OS cells underwent oligodendrocyte differentiation in vitro. To study oligodendrocyte differentiation in vivo, OS cells were transplanted into injured rat spinal cords. The transplanted cells integrated into host tissue and differentiated into oligodendrocytes. When transected saphenous nerve ends were encased in collagen-containing silicone tubes with or without OS cells, the transplanted OS cells differentiated into Schwann cells. Our data provide new insights into of the stemness of OS cells.
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Affiliation(s)
- Yu-ichiro Ohnishi
- Department of Neurosurgery, Osaka University Medical School, Suita, Osaka 565-0871, Japan.
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15
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Germain F, Istillarte M, Gómez-Vicente V, Pérez-Rico C, de la Villa P. Electroretinographical and histological study of mouse retina after optic nerve section: a comparison between wild-type and retinal degeneration 1 mice. Clin Exp Ophthalmol 2013; 41:593-602. [DOI: 10.1111/ceo.12046] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 11/11/2012] [Indexed: 11/28/2022]
Affiliation(s)
- Francisco Germain
- Departamento de Fisiología; Facultad de Medicina; Universidad de Alcalá; Madrid; Spain
| | - Mirna Istillarte
- Departamento de Fisiología; Facultad de Medicina; Universidad de Alcalá; Madrid; Spain
| | - Violeta Gómez-Vicente
- Departamento de Medicina Celular y Molecular; 3D Lab, Desarrollo; Diferenciación y Degeneración; Centro de Investigaciones Biológicas; CSIC; Madrid; Spain
| | - Consuelo Pérez-Rico
- Servicio de Oftalmología; Hospital Príncipe de Asturias; Alcalá de Henares; Spain
| | - Pedro de la Villa
- Departamento de Fisiología; Facultad de Medicina; Universidad de Alcalá; Madrid; Spain
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16
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Tomokiyo A, Maeda H, Fujii S, Monnouchi S, Wada N, Kono K, Yamamoto N, Koori K, Teramatsu Y, Akamine A. A multipotent clonal human periodontal ligament cell line with neural crest cell phenotypes promotes neurocytic differentiation, migration, and survival. J Cell Physiol 2012; 227:2040-50. [PMID: 21751215 DOI: 10.1002/jcp.22933] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Repair of injured peripheral nerve is thought to play important roles in tissue homeostasis and regeneration. Recent experiments have demonstrated enhanced functional recovery of damaged neurons by some types of somatic stem cells. It remains unclear, however, if periodontal ligament (PDL) stem cells possess such functions. We recently developed a multipotent clonal human PDL cell line, termed cell line 1-17. Here, we investigated the effects of this cell line on neurocytic differentiation, migration, and survival. This cell line expressed the neural crest cell marker genes Slug, SOX10, Nestin, p75NTR, and CD49d and mesenchymal stem cell-related markers CD13, CD29, CD44, CD71, CD90, CD105, and CD166. Rat adrenal pheochromocytoma cells (PC12 cells) underwent neurocytic differentiation when co-cultured with cell line 1-17 or in conditioned medium from cell line 1-17 (1-17CM). ELISA analysis revealed that 1-17CM contained approximately 50 pg/ml nerve growth factor (NGF). Cell line 1-17-induced migration of PC12 cells, which was inhibited by a neutralizing antibody against NGF. Furthermore, 1-17CM exerted antiapoptotic effects on differentiated PC12 cells as evidenced by inhibition of neurite retraction, reduction in annexin V and caspase-3/7 staining, and induction of Bcl-2 and Bcl-xL mRNA expression. Thus, cell line 1-17 promoted neurocytic differentiation, migration, and survival through secretion of NGF and possibly synergistic factors. PDL stem cells may play a role in peripheral nerve reinnervation during PDL regeneration.
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Affiliation(s)
- Atsushi Tomokiyo
- Faculty of Dental Science, Division of Oral Rehabilitation, Department of Endodontology and Operative Dentistry, Kyushu University, Fukuoka, Japan
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17
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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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Autophagy promotes survival of retinal ganglion cells after optic nerve axotomy in mice. Cell Death Differ 2011; 19:162-9. [PMID: 21701497 DOI: 10.1038/cdd.2011.88] [Citation(s) in RCA: 182] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Autophagy is an essential recycling pathway implicated in neurodegeneration either as a pro-survival or a pro-death mechanism. Its role after axonal injury is still uncertain. Axotomy of the optic nerve is a classical model of neurodegeneration. It induces retinal ganglion cell death, a process also occurring in glaucoma and other optic neuropathies. We analyzed autophagy induction and cell survival following optic nerve transection (ONT) in mice. Our results demonstrate activation of autophagy shortly after axotomy with autophagosome formation, upregulation of the autophagy regulator Atg5 and apoptotic death of 50% of the retinal ganglion cells (RGCs) after 5 days. Genetic downregulation of autophagy using knockout mice for Atg4B (another regulator of autophagy) or with specific deletion of Atg5 in retinal ganglion cells, using the Atg5(flox/flox) mice reduces cell survival after ONT, whereas pharmacological induction of autophagy in vivo increases the number of surviving cells. In conclusion, our data support that autophagy has a cytoprotective role in RGCs after traumatic injury and may provide a new therapeutic strategy to ameliorate retinal diseases.
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Zaverucha-do-Valle C, Gubert F, Bargas-Rega M, Coronel JLL, Mesentier-Louro LA, Mencalha A, Abdelhay E, Santiago MF, Mendez-Otero R. Bone marrow mononuclear cells increase retinal ganglion cell survival and axon regeneration in the adult rat. Cell Transplant 2010; 20:391-406. [PMID: 20719093 DOI: 10.3727/096368910x524764] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The central nervous system (CNS) of adult mammals generally does not regenerate, and many studies have attempted to identify factors that could increase neuroprotection and/or axonal outgrowth after CNS lesions. Using the optic nerve crush of rats as a model for CNS injury, we investigated the effect of intravitreal transplantation of syngeneic bone-marrow mononuclear cells (BMMCs) on the survival of retinal ganglion cells (RGC) and on the regeneration of optic axons. Control animals received intravitreal saline injections after lesion. Injections of BMMCs resulted in a 1.6-fold increase in the number of RGCs surviving 14 days after injury. The BMMC-treated animals also had increased numbers of axons, which grew up to 1.5 mm from the crush site, and also had reduced Müller glia activation. Analysis of mRNAs in all conditions revealed an increase in levels of fibroblast growth factor 2 (FGF-2) mRNA in treated animals 14 days after injury. To investigate whether the regenerated axons could reach the brain, we retrograde labeled the RGCs by injecting a lipophilic tracer into the superior colliculus. We also analyzed the expression of NGFI-A in the superficial layers of the superior colliculus as a possible marker of synaptic input from RGC axons. We found evidence that more RGCs were able to reach the brain after treatment and we showed that NGFI-A expression was higher in the treated animals 60 days after injury. These results demonstrate that transplant of BMMCs can increase neuroprotection and neuroregeneration after injury in a model of optic nerve crush, and these effects could be mediated by FGF-2.
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Affiliation(s)
- Camila Zaverucha-do-Valle
- Programa de Terapia Celular and Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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20
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Lorber B, Berry M, Logan A. Different factors promote axonal regeneration of adult rat retinal ganglion cells after lens injury and intravitreal peripheral nerve grafting. J Neurosci Res 2008; 86:894-903. [PMID: 18074384 DOI: 10.1002/jnr.21545] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We have investigated the differential mediators of the neurotrophic effects of intravitreal peripheral nerve grafting and lens injury on adult rat retinal ganglion cells (RGC). Lens injury and intravitreal peripheral nerve grafting both stimulated RGC neurite growth in vitro and axon regeneration past the optic nerve lesion site in vivo concomitant with activation of retinal glia and invasion of macrophages into the eye. These observations, together with the results of coculture studies using a macrophage-free intact peripheral nerve segment, a macrophage-free intact lens, a macrophage-rich peripheral nerve segment, or a macrophage-rich injured lens in retinal cultures suggest that the stimulation of RGC axon regeneration by lens injury and intravitreal peripheral nerve grafting share a common macrophage-derived component overlain by distinct lens-derived and peripheral nerve-derived neurotrophic factors, respectively. RGC axon regeneration following lens injury and intravitreal peripheral nerve grafting was similar in vivo, correlating with similar retinal glia activation whereas, in vitro, the level of RGC neurite outgrowth was significantly higher following intravitreal peripheral nerve grafting compared with lens injury, concomitant with the presence of increased numbers of activated retinal glia. This suggests that in vivo RGC axon regeneration induced by lens injury and peripheral nerve grafting may be limited, in part, by factors derived from activated retinal glia.
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Affiliation(s)
- Barbara Lorber
- Molecular Neuroscience Group, Division of Medical Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
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21
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Miyoshi T, Kurimoto T, Fukuda Y. Attempts to restore visual function after optic nerve damage in adult mammals. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 557:133-47. [PMID: 16955708 DOI: 10.1007/0-387-30128-3_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Retinal ganglion cells (RGCs) and their axons, i.e., optic nerve (ON) fibers, provide a good experimental model for research on damaged CNS neurons and their functional ecovery. After the ON transection most RGCs undergo retrograde and anterograde degeneration but they can be rescued and regenerated by transplantation of a piece of peripheral nerve (PN). When the nerve graft was bridged to the visual center, regenerating RGC axons can restore the central visual projection. Behavioral recovery of relatively simple visual function has been proved in such PN-grafted rodents. Intravitreal injections of various neurotrophic factors and cytokines to activate intracellular signaling mechanism of RGCs and electrical stimulation to the cut end of ON have promoting effects on their survival and axonal regeneration. Axotomized RGCs in adult cats are also shown to survive and regenerate their axons through the PN graft. Among the cat RGC types, Y cells, which function as visual motion detector, tend to survive and regenerate axons better than others. X cells, which are essential for acute vision, suffer from rapid death after ON transection but they can be rescued by intravitreal application of neurotrophins accompanied with elevation of cAMP. To restore visual function in adult mammals with damaged optic pathway, the comprehensive and integrative strategies of multiple approaches will be needed, taking care of functional diversity of RGC types.
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Affiliation(s)
- Tomomitsu Miyoshi
- Department of Physiology, Graduate School of Medicine, Osaka University, Japan
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22
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Germain F, Fernández E, de la Villa P. Morphological signs of apoptosis in axotomized ganglion cells of the rabbit retina. Neuroscience 2006; 144:898-910. [PMID: 17156937 DOI: 10.1016/j.neuroscience.2006.10.039] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Revised: 10/16/2006] [Accepted: 10/17/2006] [Indexed: 10/23/2022]
Abstract
Optic nerve section in mammals induces apoptotic death of retinal ganglion cells (RGCs). However, a small population of RGCs survives for a relatively long time. These cells experience significant morphological changes due to the apoptotic process, but some of these changes are not clearly differentiated from those experienced in necrotic cells. In the present work, rabbit RGCs were studied 1 month after optic nerve section using light microscopy after neurobiotin injection, transmission electron microscopy (EM) and scanning electron microscopy (SEM). Apoptosis was identified by terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling and characteristic signs of apoptosis were observed in the EM images. Ultrastructural analyses showed vacuolar degeneration in the cytoplasm and normal cellular structure loss. Signs of membrane changes were observed in axotomized RGCs by SEM. Early changes seen in the cell membrane suggest that axotomy may cause important changes in the cytoskeleton. We conclude that characteristic signs of apoptosis at the cell membrane level are clearly observed in rabbit RGCs after axotomy and they may be responsible for the cellular death.
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Affiliation(s)
- F Germain
- Department of Physiology, School of Medicine, University of Alcalá, Alcalá de Henares, 28871 Madrid, Spain.
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23
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Harvey AR, Hu Y, Leaver SG, Mellough CB, Park K, Verhaagen J, Plant GW, Cui Q. Gene therapy and transplantation in CNS repair: The visual system. Prog Retin Eye Res 2006; 25:449-89. [PMID: 16963308 DOI: 10.1016/j.preteyeres.2006.07.002] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Normal visual function in humans is compromised by a range of inherited and acquired degenerative conditions, many of which affect photoreceptors and/or retinal pigment epithelium. As a consequence the majority of experimental gene- and cell-based therapies are aimed at rescuing or replacing these cells. We provide a brief overview of these studies, but the major focus of this review is on the inner retina, in particular how gene therapy and transplantation can improve the viability and regenerative capacity of retinal ganglion cells (RGCs). Such studies are relevant to the development of new treatments for ocular conditions that cause RGC loss or dysfunction, for example glaucoma, diabetes, ischaemia, and various inflammatory and neurodegenerative diseases. However, RGCs and associated central visual pathways also serve as an excellent experimental model of the adult central nervous system (CNS) in which it is possible to study the molecular and cellular mechanisms associated with neuroprotection and axonal regeneration after neurotrauma. In this review we present the current state of knowledge pertaining to RGC responses to injury, neurotrophic and gene therapy strategies aimed at promoting RGC survival, and how best to promote the regeneration of RGC axons after optic nerve or optic tract injury. We also describe transplantation methods being used in attempts to replace lost RGCs or encourage the regrowth of RGC axons back into visual centres in the brain via peripheral nerve bridges. Cooperative approaches including novel combinations of transplantation, gene therapy and pharmacotherapy are discussed. Finally, we consider a number of caveats and future directions, such as problems associated with compensatory sprouting and the reformation of visuotopic maps, the need to develop efficient, regulatable viral vectors, and the need to develop different but sequential strategies that target the cell body and/or the growth cone at appropriate times during the repair process.
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Affiliation(s)
- Alan R Harvey
- School of Anatomy and Human Biology, The University of Western Australia, Crawley, WA 6009, Australia
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24
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Li S, Hu B, Tay D, So KF, Yip HKF. Intravitreal transplants of Schwann cells and fibroblasts promote the survival of axotomized retinal ganglion cells in rats. Brain Res 2004; 1029:56-64. [PMID: 15533316 DOI: 10.1016/j.brainres.2004.09.038] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2004] [Indexed: 11/23/2022]
Abstract
Schwann cells (SCs) are considered one of the major cellular components to maintain the integrity of the peripheral nervous system (PNS) neurons after injury. Intravitreal transplant of peripheral nerves or Schwann cells has been shown to enhance the regenerative ability of retinal ganglion cells (RGCs). In the present study, we compared the effects of intravitreal transplants of Schwann cells and fibroblasts, two major components of peripheral nerves, on the survival of retinal ganglion cells in adult rats after optic nerve (ON) transection. Purified Schwann cells and fibroblasts from neonatal sciatic nerves were injected into the vitreous body of adult rats. Three days after the injection, the optic nerves were transected intraorbitally. After 1 week or 1 month, surviving retinal ganglion cells were retrogradely labelled with Fluoro-Gold (FG) and the number of surviving retinal ganglion cells was counted. The retinas were further processed for 200-kDa neurofilament RT-97 immunohistochemistry. It was found that intravitreally injected- Schwann cells and -fibroblasts delayed the death of axotomized retinal ganglion cells for 1 week. In addition, in the animal group with 1 month survival time after optic nerve transection, those received a larger number of Schwann cells had more surviving retinal ganglion cells and more profusely ramified axonal processes near the optic disc. These findings reveal that both Schwann cells and fibroblasts isolated from the peripheral nerve can promote retinal ganglion cell survival after optic nerve transection, presumably by secreting neurotrophic factors. In addition, the data also demonstrate that Schwann cells could promote intraretinal axonal sprouting. Our findings demonstrate a remarkable glial source of neurotrophic factors with potential clinical applications, as autologous Schwann cells and fibroblasts can be feasibly obtained from peripheral nerves.
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Affiliation(s)
- Shengxiu Li
- Department of Anatomy, Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong SAR, China
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25
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26
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Germain F, Calvo M, de la Villa P. Rabbit retinal ganglion cell survival after optic nerve section and its effect on the inner plexiform layer. Exp Eye Res 2004; 78:95-102. [PMID: 14667831 DOI: 10.1016/j.exer.2003.09.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Structural modifications of the inner retina were studied after optic nerve section (ONS) in the rabbit. Retinal ganglion cells (RGC) were labelled by injection of Fast Blue into the optic nerve, and counted under fluorescent light in control retina and retina 7, 14, 21 and 26 days post-axotomy. Studies on retinal cross-sections were also performed. For this purpose, retinal sections were stained with haematoxylin-eosin and immunohystochemistry for alpha1 and beta2/beta3 sub-units of the GABA(A) receptors. One week after axotomy, there was no significant loss in the number of ganglion cells with respect to control counts (1086+/-173cellsmm(-2) in the visual streak and 119+/-46cellsmm(-2) in the periphery, mean+/-SD, n=5). At 14 days post-axotomy, 271+/-46cellsmm(-2) remained in the visual streak and 33+/-6cellsmm(-2) in the periphery, corresponding to a mean survival of 27%. The number of ganglion cells decreased further on the following days, reaching 7.54% 1 month after ONS. A significant reduction in the thickness of the inner plexiform and ganglion cell layers was also observed in retinal cross-sections. Immunocytochemical studies show a remarkable disorganization of the layer stratification in the inner plexiform layer (IPL). We conclude that after ONS, RGC death occurs mainly between 7 and 14 days post-axotomy and a progressive death up to 26 days, causing a decrease in the thickness of the IPL and subsequent disorganization of its layers.
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Affiliation(s)
- Francisco Germain
- Department of Physiology, School of Medicine, University of Alcala, Alcalá de Henares, Madrid, E-28871, Spain.
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27
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Germain F, Fernández E, de la Villa P. Morphometrical analysis of dendritic arborization in axotomized retinal ganglion cells. Eur J Neurosci 2003; 18:1103-9. [PMID: 12956710 DOI: 10.1046/j.1460-9568.2003.02842.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
It has been reported that section of the optic nerve in mammals causes death in >90% of the retinal ganglion cells (RGCs). The cells which survive the section experience an irreparable loss of many of their dendritic segments and a rapid retraction of the dendritic tree. However, some growth cones and abnormal processes have been also reported. Our aim was to make a quantitative study of the morphological changes found in rabbit RGCs after optic nerve section. The morphometrical analysis of the RGCs which survived the axotomy showed an increase in the diameter of the soma and a significant increase in the area of the dendritic field; also, the length of the dendritic segments was significantly longer in axotomized RGCs than in control cells. Terminal dendritic segments (T) and preterminal segments (PT) were both measured in control and axotomized cells; the length ratio of T : PT segments was significantly greater in the axotomized cells than in the controls. We conclude that RGCs which survived the axotomy experienced a significant growth of their terminal dendritic branches.
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Affiliation(s)
- Francisco Germain
- Departamento de Fisiología, Universidad de Alcala, Alcalá de Henares, E-28871 Madrid, Spain
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28
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Lossi L, Merighi A. In vivo cellular and molecular mechanisms of neuronal apoptosis in the mammalian CNS. Prog Neurobiol 2003; 69:287-312. [PMID: 12787572 DOI: 10.1016/s0301-0082(03)00051-0] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Apoptosis has been recognized to be an essential process during neural development. It is generally assumed that about half of the neurons produced during neurogenesis die before completion of the central nervous system (CNS) maturation, and this process affects nearly all classes of neurons. In this review, we discuss the experimental data in vivo on naturally occurring neuronal death in normal, transgenic and mutant animals, with special attention to the cerebellum as a study model. The emerging picture is that of a dual wave of apoptotic cell death affecting central neurons at different stages of their life. The first wave consists of an early neuronal death of proliferating precursors and young postmitotic neuroblasts, and appears to be closely linked to cell cycle regulation. The second wave affects postmitotic neurons at later stages, and is much better understood in functional terms, mainly on the basis of the neurotrophic concept in its broader definition. The molecular machinery of late apoptotic death of postmitotic neurons more commonly follows the mitochondrial pathway of intracellular signal transduction, but the death receptor pathway may also be involved.Undoubtedly, analysis of naturally occurring neuronal death (NOND) in vivo will offer a basis for parallel and future studies aiming to elucidate the mechanisms of pathologic neuronal loss occurring as the result of conditions such as neurodegenerative disorders, trauma or ischemia.
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Affiliation(s)
- L Lossi
- Department of Veterinary Morphophysiology, University of Torino, Via Leonardo da Vinci 44, I-10095 (TO), Grugliasco, Italy.
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Affiliation(s)
- Leonard A Levin
- Department of Ophthalmology and Visual Sciences, University of Wisconsin Medical School, 600 Highland Avenue, Madison, WI 53792, USA
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Gołka B, Lewin-Kowalik J, Swiech-Sabuda E, Larysz-Brysz M, Górka D, Małecka-Tendera E. Predegenerated peripheral nerve grafts rescue retinal ganglion cells from axotomy-induced death. Exp Neurol 2001; 167:118-25. [PMID: 11161599 DOI: 10.1006/exnr.2000.7540] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The inability of axons to grow across damaged central nervous system tissue is a well-known consequence of injury to the brain and spinal cord of adult mammals. Our previous studies showed that predegenerated peripheral nerve grafts facilitate neurite outgrowth from the injured hippocampus and that this effect was particularly distinct when 7-, 28-, and 35-day-predegenerated nerve grafts were used. The purpose of the present study was to use the above method to induce and support the regrowth of injured nerve fibers as well as the survival of retinal ganglion cells (RGCs). Adult Sprague-Dawley rats were assigned to three groups. In the experimental groups transected optic nerve was grafted with peripheral nerve (predegenerated for 7 days (PD) or nonpredegenerated). In the control group, the optic nerve was totally transected. RGCs and growing fibers labeled with fluorescent tracers were examined. They were counted and the results were subjected to statistical analysis. Retinal ganglion cells survived in the groups treated with predegenerated as well as nonpredegenerated grafts; however, the number of surviving retinal ganglion cells was significantly higher in the first one. In both groups the regrowth of the transected optic nerve was observed but the distance covered by regenerating fibers was longer in the PD group. No fibers inside grafts and no labeled cells in retinas were present in the control animals. On the basis of the obtained results we can state that the predegeneration of grafts enhance their neurotrophic influence upon the injured retinal ganglion cells.
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Affiliation(s)
- B Gołka
- Department of Physiology, Silesian Medical University, ul. Medyków 18, Katowice, 40-762, Poland
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31
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Abstract
The ability of peripheral nervous system (PNS) but not central nervous system (CNS) neurons to regenerate their axons is a striking peculiarity of higher vertebrates. Much research has focused on the inhibitory signals produced by CNS glia that thwart regenerating axons. Less attention has been paid to the injury-induced loss of trophic stimuli needed to promote the survival and regeneration of axotomized neurons. Could differences in the mechanisms that control CNS and PNS neuronal survival and growth also contribute to the disparity in regenerative capacity? Here we review recent studies concerning the nature of the signals necessary to promote neuronal survival and growth, with an emphasis on their significance to regeneration after CNS injury.
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Affiliation(s)
- J L Goldberg
- Department of Neurobiology, Stanford University School of Medicine, California 94305-5125, USA.
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Abstract
In a relatively short period of time covering the last 2 decades, regeneration of retinofugal axons has become one of most prominent experimental models in restorative neurobiology. There is now a significant knowledge both on the mechanisms governing retinal ganglion cell responses to transection of the optic nerve, and the subsequent cell-cell interactions accumulating in death of the neurons. In addition, retinofugal axons served as an excellent model to examine whether, and to conclude that these axons have remarkable abilities for re-growth. This last issue was of invaluable importance, because axons could regenerate in vivo, into peripheral nerve grafts, and last but not least within the white matter of the cut optic nerve. As it stands to date, the extremely complex aspects of axonal regeneration will probably be understood within the retinofugal pathway. Final elucidation of this delicate system will essentially lead to some revision of our knowledge concerning neurotraumatology and CNS-repair.
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Affiliation(s)
- P Heiduschka
- Department of Experimental Ophthalmology, University of Münster Eye Hospital, Domagkstrasse 15, 48149 Münster, Germany
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Abstract
A variety of neurotrophic factors can influence the cell functions of the developing, mature and injured retinal ganglion cells. The discovery that retinal ganglion cell loss can be alleviated by neurotrophic factors has generated a great deal of interest in the therapeutic potential of these molecules. Recently, evidence has provided valuable information on the receptors that mediate these events and the intracellular signaling cascades after the binding of these ligands. Signaling by neurotrophic factors does not seem to restrict to retrograde messenger from the target but also includes local interactions with neighbouring cells along the axonal pathways, anterograde signaling from the afferents and autocrine signaling. More insight into the mechanisms of action of neurotrophic factors and the signal transduction pathway leading to the protection and regeneration of retinal ganglion cells may allow the design of new therapeutic strategies.
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Affiliation(s)
- H K Yip
- Department of Anatomy, Faculty of Medicine, The University of Hong Kong, Hong Kong.
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Abstract
Retinal ganglion cells of transgenic mice overexpressing the anti-apoptotic protein Bcl-2 in neurons show a dramatic increase of survival rate after axotomy. We used this experimental system to test the regenerative potentials of central neurons after reduction of nonpermissive environmental factors. Survival of retinal ganglion cells 1 month after intracranial crush of the optic nerve was found to be 100% in adult bcl-2 mice and 44% in matched wild-type (wt) mice. In the optic nerve, and particularly at the crush site, fibers regrowing spontaneously or simply sprouting were absent in both wt and bcl-2 mice. We attempted to stimulate regeneration implanting in the crushed nerves hybridoma cells secreting antibodies that neutralize central myelin proteins, shown to inhibit regeneration (IN-1 antibodies) (Caroni and Schwab, 1988). Again, we found that regeneration of fibers beyond the site of crush was virtually absent in the optic nerves of both wt and bcl-2 mice. However, in bcl-2 animals treated with IN-1 antibodies, fibers showed sprouting in the proximity of the hybridoma implant. These results suggest that neurons overexpressing bcl-2 are capable of surviving axotomy and sprout when faced with an environment in which inhibition of regeneration has been reduced. Nevertheless, extensive regeneration does not occur, possibly because other factors act by preventing it.
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Chierzi S, Strettoi E, Cenni MC, Maffei L. Optic nerve crush: axonal responses in wild-type and bcl-2 transgenic mice. J Neurosci 1999; 19:8367-76. [PMID: 10493738 PMCID: PMC6783029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
Retinal ganglion cells of transgenic mice overexpressing the anti-apoptotic protein Bcl-2 in neurons show a dramatic increase of survival rate after axotomy. We used this experimental system to test the regenerative potentials of central neurons after reduction of nonpermissive environmental factors. Survival of retinal ganglion cells 1 month after intracranial crush of the optic nerve was found to be 100% in adult bcl-2 mice and 44% in matched wild-type (wt) mice. In the optic nerve, and particularly at the crush site, fibers regrowing spontaneously or simply sprouting were absent in both wt and bcl-2 mice. We attempted to stimulate regeneration implanting in the crushed nerves hybridoma cells secreting antibodies that neutralize central myelin proteins, shown to inhibit regeneration (IN-1 antibodies) (Caroni and Schwab, 1988). Again, we found that regeneration of fibers beyond the site of crush was virtually absent in the optic nerves of both wt and bcl-2 mice. However, in bcl-2 animals treated with IN-1 antibodies, fibers showed sprouting in the proximity of the hybridoma implant. These results suggest that neurons overexpressing bcl-2 are capable of surviving axotomy and sprout when faced with an environment in which inhibition of regeneration has been reduced. Nevertheless, extensive regeneration does not occur, possibly because other factors act by preventing it.
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Affiliation(s)
- S Chierzi
- Istituto di Neurofisiologia del Consiglio Nazionale delle Ricerche, 56127 Pisa, Italy
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36
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Lai MY, Cho EY. Regenerative sprouting of retinal ganglion cells of adult hamsters induced by the epineurium of a peripheral nerve. Brain Res 1999; 823:241-8. [PMID: 10095036 DOI: 10.1016/s0006-8993(99)01202-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Although it is known that transplantation of a peripheral nerve (PN) to the damaged central nervous system (CNS) promotes axonal regeneration, the interactions of cellular components of the PN with CNS neurons are still not well defined. Schwann cells in the PN are thought to be the major element involved in supporting CNS regeneration, but very little information exists with regard to whether other PN components also play an active role. Using our previously established model of transplanting a PN segment into the vitreous to stimulate regenerative sprouting of retinal ganglion cells (RGCs), we found that the epineurium isolated from a PN which had been pre-injured by transection was able to induce RGC sprouting when implanted intravitreally. Since the epineurium is composed mainly of connective tissue components and is devoid of Schwann cells, our results suggest that other cellular elements of the PN besides Schwann cells may have the potential to support CNS regeneration.
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Affiliation(s)
- M Y Lai
- Department of Anatomy, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
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37
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Abstract
Retinal ganglion cells (RGCs) and their projections in the optic nerve offer a convenient model to study survival and regeneration of mammalian central nervous system (CNS) nerve cells following injury. Possible factors affecting the death of RGCs following axotomy and various approaches to rescue the axotomized RGCs are discussed. In addition, two main strategies currently used to enhance axonal regeneration of damaged RGCs are described. The first focuses on overcoming the unfavorable extrinsic CNS environment and the second concentrates on upregulating the intrinsic growth potential of RGCs. Thus, the failure or success of RGC axonal regrowth after injury depends on the complicated interplay between the extrinsic and intrinsic factors.
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Affiliation(s)
- K F So
- Department of Anatomy, Faculty of Medicine, University of Hong Kong, China.
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Fagiolini M, Pizzorusso T, Porciatti V, Cenni M, Maffei L. Transplant of Schwann cells allows normal development of the visual cortex of dark-reared rats. Eur J Neurosci 1997; 9:102-12. [PMID: 9042574 DOI: 10.1111/j.1460-9568.1997.tb01358.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Visual experience is necessary for the correct development of the visual cortex. Dark-rearing from birth affects normal maturation of the functional properties of mammalian visual cortex: cortical cells show rapid habituation to repeated stimulation, decreased orientation selectivity, and enlarged receptive fields. Spatial resolution and response latency are also impaired. Recent experiments have demonstrated that visual deprivation reduces the expression of neurotrophins in the visual cortex. We formulated the hypothesis that visual experience drives the maturation of functional properties of the visual cortex by regulating cortical levels of neurotrophins. If this hypothesis is correct, exogenous supply of neurotrophins during dark-rearing from birth should prevent, or at least ameliorate, the effects of a lack of visual experience. Since Schwann cells are efficient biological minipumps of neurotrophic factors, we transplanted 1.0 or 1.5 x 10(6) Schwann cells or infused vehicle solution as a control into the lateral ventricles of 13 day old rats reared in total darkness from birth until the end of the critical period (postnatal day 45). Single-cell responses and visual-evoked potentials were recorded from the binocular zone of the primary visual cortex of each group. We found that in Schwann cell-transplanted animals all parameters tested were significantly improved upon those of dark-reared control rats and were in the range of normal adult values. Thus, Schwann cell transplant contributed to the normal development of visual response properties in the visual cortex, compensating for a complete absence of visual experience.
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Protection of retinal ganglion cells from natural and axotomy-induced cell death in neonatal transgenic mice overexpressing bcl-2. J Neurosci 1996. [PMID: 8753880 DOI: 10.1523/jneurosci.16-13-04186.1996] [Citation(s) in RCA: 168] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Approximately half of the retinal ganglion cells (RGCs) present in the rodent retina at birth normally die during early development. Overexpression of the photo-oncogene bcl-2 recently has been shown to rescue some neuronal populations from natural cell death and from degeneration induced by axotomy of nerves within the peripheral nervous system. Here we study in vivo the role of the overexpression of bcl-2 in the natural cell death of RGCs and in the degenerative process induced in these cells by transection of the optic nerve. We find that in newborn bcl-2 transgenic mice, the number of RGCs undergoing natural cell death is considerably lower than in wild-type pups. Consistently, a vast majority (90%) of the ganglion cells found in the retina of neonatal transgenics are maintained in adulthood, whereas only 40% survive in wild-type mice. After transection of the optic nerve, the number of degenerating ganglion cells, determined by counting pyknotic nuclei or nuclei with fragmented DNA, is substantially reduced in transgenic mice. In wild-type animals, almost 50% of ganglion cells degenerate in the 24 hr after the lesion, whereas almost the entire ganglion cell population survives axotomy in transgenic mice. Therefore, overexpression of bcl-2 is effective in preventing degeneration of this neuronal population, raising the possibility that ganglion cells are dependent on the endogenous expression of bcl-2 for survival. The remarkable rescue capacity of bcl-2 overexpression in these neurons makes it an interesting model for studying natural cell death and responses to injury in the CNS.
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Porciatti V, Pizzorusso T, Cenni MC, Maffei L. The visual response of retinal ganglion cells is not altered by optic nerve transection in transgenic mice overexpressing Bcl-2. Proc Natl Acad Sci U S A 1996; 93:14955-9. [PMID: 8962163 PMCID: PMC26244 DOI: 10.1073/pnas.93.25.14955] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/1996] [Accepted: 10/04/1996] [Indexed: 02/03/2023] Open
Abstract
Attempts to rescue retinal ganglion cells from retrograde degeneration have had limited success, and the residual function of surviving neurons is not known. Recently, it has been found that axotomized retinal ganglion cells die by apoptotic mechanisms. We have used adult transgenic mice overexpressing the Bcl-2 protein, a powerful inhibitor of apoptosis, as a model for preventing injury-induced cell death in vivo. Several months after axotomy, the majority of retinal ganglion cells survived and exhibited normal visual responses. In control wild-type mice, the vast majority of axotomized retinal ganglion cells degenerated, and the physiological responses were abolished. These results suggest that strategies aimed at increasing Bcl-2 expression, or mimicking its function, might effectively counteract trauma-induced cell death in the central nervous system. Neuronal survival is a necessary condition in the challenge for promoting regeneration and eventually restoring neuronal function.
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Affiliation(s)
- V Porciatti
- Istituto di Neurofisiologia del Consiglio Nazionale delle Ricerche, Pisa, Italy
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Cenni MC, Bonfanti L, Martinou JC, Ratto GM, Strettoi E, Maffei L. Long-term survival of retinal ganglion cells following optic nerve section in adult bcl-2 transgenic mice. Eur J Neurosci 1996; 8:1735-45. [PMID: 8921264 DOI: 10.1111/j.1460-9568.1996.tb01317.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The bcl-2 gene codes for a protein that acts as a powerful inhibitor of active cell death. Since the transection of the optic nerve in adult mammalians starts a massive process of degeneration in retinal ganglion cells, we investigated whether the overexpression of bcl-2 in adult transgenic mice can protect the axotomized ganglion cells. We performed intracranial optic nerve transection on both wild type and transgenic adult mice, and we tested cell survival 2 or 3.5 months after axotomy. The percentage of surviving ganglion cells after optic nerve section was computed by combining the counts of the optic nerve fibres in intact nerves with the cell density measures of the ganglion cell layer of axotomized retinae. From these data we found that in transgenic mice approximately 65% of ganglion cells survived 3.5 months after axotomy. In contrast, 2 months after surgery, < 10% of ganglion cells were left in wild type retinae. We have also examined the morphology and fine structure of the proximal stump of the sectioned optic nerves by light and electron microscopy. In the transgenic mice a very large number of axons survived after surgery and they still exhibited fairly normal morphology and ultrastructure. On the other hand the wild type transected nerves had only a few visible axons that displayed clear signs of degeneration. We conclude that the overexpression of Bcl-2 protein in central neurons is a very effective strategy to ensure long-term survival in axotomized cells.
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Affiliation(s)
- M C Cenni
- Istituto di Neurofisiologia del CNR, Italy
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42
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Bonfanti L, Strettoi E, Chierzi S, Cenni MC, Liu XH, Maffei L, Rabacchi SA. Protection of retinal ganglion cells from natural and axotomy-induced cell death in neonatal transgenic mice overexpressing bcl-2. J Neurosci 1996; 16:4186-94. [PMID: 8753880 PMCID: PMC6578989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Approximately half of the retinal ganglion cells (RGCs) present in the rodent retina at birth normally die during early development. Overexpression of the photo-oncogene bcl-2 recently has been shown to rescue some neuronal populations from natural cell death and from degeneration induced by axotomy of nerves within the peripheral nervous system. Here we study in vivo the role of the overexpression of bcl-2 in the natural cell death of RGCs and in the degenerative process induced in these cells by transection of the optic nerve. We find that in newborn bcl-2 transgenic mice, the number of RGCs undergoing natural cell death is considerably lower than in wild-type pups. Consistently, a vast majority (90%) of the ganglion cells found in the retina of neonatal transgenics are maintained in adulthood, whereas only 40% survive in wild-type mice. After transection of the optic nerve, the number of degenerating ganglion cells, determined by counting pyknotic nuclei or nuclei with fragmented DNA, is substantially reduced in transgenic mice. In wild-type animals, almost 50% of ganglion cells degenerate in the 24 hr after the lesion, whereas almost the entire ganglion cell population survives axotomy in transgenic mice. Therefore, overexpression of bcl-2 is effective in preventing degeneration of this neuronal population, raising the possibility that ganglion cells are dependent on the endogenous expression of bcl-2 for survival. The remarkable rescue capacity of bcl-2 overexpression in these neurons makes it an interesting model for studying natural cell death and responses to injury in the CNS.
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Affiliation(s)
- L Bonfanti
- Istituto di Neurofisiologia del Consiglio Nazionale delle Ricerche, Pisa, Italy
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43
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Berry M, Carlile J, Hunter A. Peripheral nerve explants grafted into the vitreous body of the eye promote the regeneration of retinal ganglion cell axons severed in the optic nerve. JOURNAL OF NEUROCYTOLOGY 1996; 25:147-70. [PMID: 8699196 DOI: 10.1007/bf02284793] [Citation(s) in RCA: 207] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We have conducted experiments in the adult rat visual system to assess the relative importance of an absence of trophic factors versus the presence of putative growth inhibitory molecules for the failure of regeneration of CNS axons after injury. The experiments comprised three groups of animals in which all optic nerves were crushed intra-orbitally: an optic nerve crush group had a sham implant-operation on the eye; the other two groups had peripheral nerve tissue introduced into the vitreous body; in an acellular peripheral nerve group, a frozen/thawed teased sciatic nerve segment was grafted, and in a cellular peripheral nerve group, a predegenerate teased segment of sciatic nerve was implanted. The rats were left for 20 days and their optic nerves and retinae prepared for immunohistochemical examination of both the reaction to injury of axons and glia in the nerve and also the viability of Schwann cells in the grafts. Anterograde axon tracing with rhodamine-B provided unequivocal qualitative evidence of regeneration in each group, and retrograde HRP tracing gave a measure of the numbers of axons growing across the lesion by counting HRP filled retinal ganglion cells in retinal whole mounts after HRP injection into the optic nerve distal to the lesion. No fibres crossed the lesion in the optic nerve crush group and dense scar tissue was formed in the wound site. GAP-43-positive and rhodamine-B filled axons in the acellular peripheral nerve and cellular peripheral nerve groups traversed the lesion and grew distally. There were greater numbers of regenerating fibres in the cellular peripheral nerve compared to the acellular peripheral nerve group. In the former, 0.6-10% of the retinal ganglion cell population regenerated axons at least 3-4 mm into the distal segment. In both the acellular peripheral nerve and cellular peripheral nerve groups, no basal lamina was deposited in the wound. Thus, although astrocyte processes were stacked around the lesion edge, a glia limitans was not formed. These observations suggest that regenerating fibres may interfere with scarring. Viable Schwann cells were found in the vitreal grafts in the cellular peripheral nerve group only, supporting the proposition that Schwann cell derived trophic molecules secreted into the vitreous stimulated retinal ganglion cell axon growth in the severed optic nerve. The regenerative response of acellular peripheral nerve-transplanted animals was probably promoted by residual amounts of these molecules present in the transplants after freezing and thawing. In the optic nerves of all groups the astrocyte, microglia and macrophage reactions were similar. Moreover, oligodendrocytes and myelin debris were also uniformly distributed throughout all nerves. Our results suggest either that none of the above elements inhibit CNS regeneration after perineuronal neurotrophin delivery, or that the latter, in addition to mobilising and maintaining regeneration, also down regulates the expression of axonal growth cone-located receptors, which normally mediate growth arrest by engaging putative growth inhibitory molecules of the CNS neuropil.
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Affiliation(s)
- M Berry
- Division of Anatomy and Cell Biology, UMDS (Guy's Campus), London, UK
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Ng TF, So KF, Chung SK. Influence of peripheral nerve grafts on the expression of GAP-43 in regenerating retinal ganglion cells in adult hamsters. JOURNAL OF NEUROCYTOLOGY 1995; 24:487-96. [PMID: 7561957 DOI: 10.1007/bf01179974] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have examined the ability of axotomized retinal ganglion cells in adult hamsters, to regenerate axons into a peripheral nerve graft attached to the optic nerve and the expression of GAP-43 by these neurons. We also examined the effect on these events of transplanting a segment of peripheral nerve to the vitreous body. The left optic nerves in three groups of hamsters were replaced with a long segment of peripheral nerve attached to the proximal stump of the optic nerve approximately 2 mm from the optic disc to induce regeneration of retinal ganglion cells into the peripheral nerve. An additional segment of peripheral nerve was transplanted into the vitreous of the left eye in the second group. The animals from the first and second groups were allowed to survive for 1-8 weeks and the number of regenerating retinal ganglion cells was determined by applying the retrograde tracer, Fluoro-Gold to the peripheral nerve graft and the expression of GAP-43 was studied by immunocytochemistry in the same retinas. As a control, a segment of optic nerve was transplanted into the vitreous body of the left eye in the third group of hamsters. These animals were allowed to survive for 4 weeks and the number of regenerating retinal ganglion cells was counted as in Groups 1 and 2. The percentages of the regenerating retinal ganglion cells which also expressed GAP-43 were very high at all time points in Group 1 (with no intravitreal peripheral nerve) and Group 2 (with intravitreal peripheral nerve) and at 4 weeks for the Group 3 (with intravitreal optic nerve) animals. In addition, the number of regenerating retinal ganglion cells, the number of retinal ganglion cells expressing GAP-43 and the number of regenerating retinal ganglion cells which also expressed GAP-43 were much higher in Group 2 than in Group 1 at all the time points and it was also much higher in Group 2 than in Group 3 at 4 weeks whereas there was no significant difference between the results from Groups 1 and 3 at 4 weeks. These data suggested that there was a close correlation between the number of the axotomized retinal ganglion cells regenerating axons into the peripheral nerve graft attached to the optic nerve and the expression of GAP-43.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- T F Ng
- Department of Anatomy, University of Hong Kong
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45
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Watanabe M, Sawai H, Fukuda Y. Number and dendritic morphology of retinal ganglion cells that survived after axotomy in adult cats. JOURNAL OF NEUROBIOLOGY 1995; 27:189-203. [PMID: 7658200 DOI: 10.1002/neu.480270206] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Retinal ganglion cells (RGCs) of adult cats were labeled by injection of diI into the proximal stump of completely transected optic nerves. Approximately 2% to 5% of the RGC population appeared viable 2 months after these axotomies, based on diI retention. The morphological type and dendritic arbor of these surviving RGCs were examined after intracellular injections of Lucifer Yellow into diI-labeled RGCs. Postaxotomy survival rate was much higher for alpha-like cells than for beta-like cells. However, in one of four retinas examined, a large number of RGCs seemed to survive axotomy, and among these, beta cells survived at an unusually high rate. Dendritic arbors of surviving RGCs were also examined after intracellular injection of horseradish peroxidase. Some dendrites of these RGCs lacked branches and were thin in caliber. Other dendrites displayed many spiny processes and bulbous swellings. Essentially, these results confirm the previous suggestion that alpha cells survive axotomy longer than beta cells. The ability of alpha cells to regenerate axons may thus be attributable to their relatively high resistance to axotomy. The atypical dendritic profiles seen after optic nerve transection may reflect either degeneration or regrowth of dendrites.
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Affiliation(s)
- M Watanabe
- Department of Physiology, Aichi Human Service Center, Japan
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46
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Métin C, Irons WA, Frost DO. Retinal ganglion cells in normal hamsters and hamsters with novel retinal projections. I. Number, distribution, and size. J Comp Neurol 1995; 353:179-99. [PMID: 7745130 DOI: 10.1002/cne.903530203] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We examined the number, spatial distribution, and size of ganglion cells in the retinae of normal Syrian hamsters and hamsters with retinal projections to the auditory and somatosensory nuclei of the thalamus, induced by neonatal surgery. As revealed by retrograde filling with horseradish peroxidase, there are about 64,600 contralaterally projecting retinal ganglion cells (RGCs) and 1,700 ipsilaterally projecting RGCs in the retinae of normal adult hamsters. Contralaterally projecting RGCs are distributed throughout the retina and have two local density peaks located within a central streak of high RGC density that is oriented approximately along the nasal-temporal axis. RGC density falls above and below the central streak, with a steeper gradient towards the upper retina. Ipsilaterally projecting RGCs are diffusely distributed within a crescent at the inferotemporal retinal periphery and are most dense at the internal border of the crescent. The soma diameter of contralaterally projecting RGCs ranges from 6 to 25 microns; the diameter distribution is unimodal, with a peak in the 10-13 microns range and is skewed toward smaller values, with an elongated tail towards higher values. Contralaterally projecting RGCs tend to be smaller in regions of higher density. Ipsilaterally projecting RGCs tend to be larger than contralaterally projecting RGCs both globally and within the temporal crescent, and their size distributions tend to be less regular and less well related to local density. The retinae of neonatally operated hamsters with novel retinal projections to the auditory. and somatosensory systems contain about one-fourth the normal number of contralaterally projecting RGCs, whose relative density distribution is approximately normal despite the drastic reduction of absolute RGC density. The range and distribution of RGC soma diameters are similar in normal and neonatally operated hamsters, and, in operated as in normal hamsters, contralaterally projecting RGC somata tend to be smaller in regions of higher density. Our results in normal hamsters suggest a role for intraretinal mechanisms in the determination of RGC size. Our findings in neonatally operated hamsters suggest that, despite the reduced number of RGCs in these animals, the same types of RGCs are found in the retinae of normal and neonatally operated hamsters.
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Affiliation(s)
- C Métin
- Institut Alfred Fessard, CNRS UPR 2212, Gif-sur-Yvette, France
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Pizzorusso T, Fagiolini M, Fabris M, Ferrari G, Maffei L. Schwann cells transplanted in the lateral ventricles prevent the functional and anatomical effects of monocular deprivation in the rat. Proc Natl Acad Sci U S A 1994; 91:2572-6. [PMID: 8146156 PMCID: PMC43411 DOI: 10.1073/pnas.91.7.2572] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We investigated whether the transplant of Schwann cells prevents the physiological and morphological effects of monocular deprivation in the rat. On the day of eye opening in rats (postnatal day 14), we transplanted Schwann cells in the lateral ventricles and sutured the eyelids of one eye. After 20-30 days, at the end of the critical period for the visual system development, we analyzed the functional properties of visual cortical neurons. Spontaneous discharge, orientation selectivity, and receptive field size of visual cortical neurons in transplanted animals were in the normal range. Transplantation of Schwann cells prevented the detrimental effects of monocular deprivation on ocular dominance and binocularity of cortical neurons. Visual acuity of the deprived eye estimated by visually evoked potentials was also normal. Schwann cells derived from adult animals were as effective as those derived from neonates. The effects of Schwann cells on monocular deprivation were dependent upon the number of cells present in the transplant so that 10(6) Schwann cells were sufficient to prevent the effect of monocular deprivation, whereas 10(5) and 3.3 x 10(5) Schwann cells were ineffective, and 6.3 x 10(5) cells gave variable results. Shrinkage of the deprived lateral geniculate neurons was prevented by a transplant of 10(6) cells. In rats transplanted with hybridoma cells producing an antibody that functionally blocks nerve growth factor (NGF), we found that the effect of cotransplanted Schwann cells on monocular deprivation was partly counteracted. We conclude that transplantation of Schwann cells prevents both functional and anatomical effects of monocular deprivation, presumably acting through the production of NGF. We propose that transplants of Schwann cells could be a promising technique for clinical applications.
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Bhide PG, West WC, Fry KR, Frost DO. An immunocytochemical marker for hamster retinal ganglion cells. JOURNAL OF NEUROCYTOLOGY 1994; 23:167-77. [PMID: 8006677 DOI: 10.1007/bf01181558] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We examined the specificity and developmental time course of the labelling of retinal ganglion cells in Syrian hamsters by a monoclonal antibody AB5. In adult hamsters, AB5 selectively labelled somata in the ganglion cell layer, dendrites in the inner plexiform layer and axons in the nerve fibre layer. When retinal ganglion cells were retrogradely labelled with DiI prior to AB5 immunocytochemistry, all of the retrogradely labelled retinal ganglion cells in the ganglion cell layer were AB5 immunoreactive, indicating that AB5 labels all classes of ganglion cell in that layer. In retinae depleted of retinal ganglion cells by neonatal optic nerve transections, AB5 did not label any somata or processes, indicating that AB5 specifically labels retinal ganglion cells. During development, AB5 labelling first appeared as a weak staining of cell bodies in the ganglion cell layer on postnatal day 12 (P12; PO = first 24 h following birth) and acquired the staining pattern seen in the adult by postnatal day 14. From the onset of AB5 immunoreactivity, AB5-labelled somata of varying sizes were present across the entire retinal surface. Although AB5 labelled retinal ganglion cell axons in the nerve fibre layer of the retina it did not label the optic nerve or retinal ganglion cell axons in the brain at any age examined. AB5 labelling was also found to be compatible with bromodeoxyuridine immunocytochemistry and, therefore, useful for determining the time of generation of hamster retinal ganglion cells.
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Affiliation(s)
- P G Bhide
- Department of Neurology, Massachusetts General Hospital, Boston
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Dezawa M, Nagano T. Contacts between regenerating axons and the Schwann cells of sciatic nerve segments grafted to the optic nerve of adult rats. JOURNAL OF NEUROCYTOLOGY 1993; 22:1103-12. [PMID: 8106882 DOI: 10.1007/bf01235752] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The relation between Schwann cells, basal laminae and axons during retinal ganglion cell regeneration was studied by using cellular, acellular and partially acellular sciatic nerve autografts into the optic nerve. Acellular grafts were achieved by temporary compression which eliminates living Schwann cells and axons. The compressed sciatic nerve together with the intact portion was used as a partially acellular graft. The compressed portion was anastomosed to the optic nerve and the intact portion was situated distally. After 3-21 days post-operation, the grafts were studied by thin sectioning and freeze-fracture. Axons were seen to regenerate into cellular grafts in contact with Schwann cells after one week, but not into acellular grafts for the entire period. In the partially acellular grafts, regenerating axons were first observed after two weeks and were always in contact with Schwann cells migrating from the intact portion. Moreover, membrane specializations, fuzzy materials in the space between apposed membranes, and putative tight junctions, were found between regenerated axons including growth cone and Schwann cells, and between adjoining Schwann cells. An extensive meshwork of putative tight junctions was displayed between reforming perineurial cells surrounding the groups of Schwann cells and associated axons. Gap junctions were seen between adjoining Schwann cells, and between reforming perineurial cells. These results suggest that the axonal contact with Schwann cell surfaces plays an important role in retinal ganglion cell regeneration.
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Affiliation(s)
- M Dezawa
- Department of Anatomy, School of Medicine, Chiba University, Japan
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50
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Calderon RO, Maggio B, Neuberger TJ, De Vries GH. Surface behavior of axolemma monolayers: physico-chemical characterization and use as supported planar membranes for cultured Schwann cells. J Neurosci Res 1993; 34:206-18. [PMID: 8450564 DOI: 10.1002/jnr.490340208] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The axolemma membrane forms a stable and reproducible monomolecular layer at the air-aqueous interface. The major lipids and proteins are present in this monolayer in molar ratios similar to the original membrane. Acetylcholinesterase and Na-K-ATPase activities are preserved in the monolayer to levels of 64% and 25%, respectively. The total lipid fraction forms a homogeneously mixed phase. The presence of proteins in the monolayer introduces surface inhomogeneties. Among other features, this is revealed by the presence of two values of lateral pressure at which the monolayer shows partial or total collapse: a broad partial collapse at surface pressures between 13 to 30 mN/m and a sharp collapse point at 46 mN/m. The average molecular areas, the broad collapse point, and the variation of the surface potential per molecule suggest the relocation of protein components at surface pressures between 13 to 30 mN/m. The behavior is consistent with the extrusion and exposure of proteins toward the aqueous medium that depends on the lateral pressure. Schwann cells grown on coverslips coated with axolemma monolayers at 13 mN/m (beginning of the broad collapse) and 34 mN/m (above the broad collapse) recognize the difference in the surface organization of axolemma caused by the lateral pressure which affects their proliferation, morphology, and spatial pattern of organization. Our results show for the first time that response of Schwann cells depends on the intermolecular organization of the axolemma surface with which they interact. These results suggest that the local expression of putative surface molecules of axolemma that may mediate membrane recognition and the signalling of morphological and proliferative changes can be modulated by long range supramolecular properties.
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Affiliation(s)
- R O Calderon
- Department of Biochemistry and Molecular Biophysics, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0614
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