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Ronan R, Kshirsagar A, Rebelo AL, Sunny A, Kilcoyne M, Flaherty RO, Rudd PM, Schlosser G, Saldova R, Pandit A, McMahon SS. Distinct Glycosylation Responses to Spinal Cord Injury in Regenerative and Nonregenerative Models. J Proteome Res 2022; 21:1449-1466. [PMID: 35506863 PMCID: PMC9171824 DOI: 10.1021/acs.jproteome.2c00043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Indexed: 11/28/2022]
Abstract
Traumatic spinal cord injury (SCI) results in disruption of tissue integrity and loss of function. We hypothesize that glycosylation has a role in determining the occurrence of regeneration and that biomaterial treatment can influence this glycosylation response. We investigated the glycosylation response to spinal cord transection in Xenopus laevis and rat. Transected rats received an aligned collagen hydrogel. The response compared regenerative success, regenerative failure, and treatment in an established nonregenerative mammalian system. In a healthy rat spinal cord, ultraperformance liquid chromatography (UPLC) N-glycoprofiling identified complex, hybrid, and oligomannose N-glycans. Following rat SCI, complex and outer-arm fucosylated glycans decreased while oligomannose and hybrid structures increased. Sialic acid was associated with microglia/macrophages following SCI. Treatment with aligned collagen hydrogel had a minimal effect on the glycosylation response. In Xenopus, lectin histochemistry revealed increased levels of N-acetyl-glucosamine (GlcNAc) in premetamorphic animals. The addition of GlcNAc is required for processing complex-type glycans and is a necessary foundation for additional branching. A large increase in sialic acid was observed in nonregenerative animals. This work suggests that glycosylation may influence regenerative success. In particular, loss of complex glycans in rat spinal cord may contribute to regeneration failure. Targeting the glycosylation response may be a promising strategy for future therapies.
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Affiliation(s)
- Rachel Ronan
- SFI
Research Centre for Medical Devices (CÚRAM), National University of Ireland, Galway, Galway H91 W2TY, Ireland
- Discipline
of Anatomy, National University of Ireland, Galway H91 W5P7, Ireland
| | - Aniket Kshirsagar
- SFI
Research Centre for Medical Devices (CÚRAM), National University of Ireland, Galway, Galway H91 W2TY, Ireland
| | - Ana Lúcia Rebelo
- SFI
Research Centre for Medical Devices (CÚRAM), National University of Ireland, Galway, Galway H91 W2TY, Ireland
| | - Abbah Sunny
- SFI
Research Centre for Medical Devices (CÚRAM), National University of Ireland, Galway, Galway H91 W2TY, Ireland
| | - Michelle Kilcoyne
- Discipline
of Microbiology, National University of
Ireland, Galway, Galway H91 W2TY, Ireland
| | - Roisin O’ Flaherty
- Department
of Chemistry, Maynooth University, Maynooth, Co., Kildare W23 F2H6, Ireland
- The
National Institute for Bioprocessing, Research,
and Training (NIBRT), Dublin A94 X099, Ireland
| | - Pauline M. Rudd
- The
National Institute for Bioprocessing, Research,
and Training (NIBRT), Dublin A94 X099, Ireland
- Conway
Institute, University College Dublin, Belfield, Dublin 4 D04
PR94, Ireland
| | - Gerhard Schlosser
- School of
Natural Science, National University of
Ireland, Galway, Galway H91 W2TY, Ireland
| | - Radka Saldova
- SFI
Research Centre for Medical Devices (CÚRAM), National University of Ireland, Galway, Galway H91 W2TY, Ireland
- The
National Institute for Bioprocessing, Research,
and Training (NIBRT), Dublin A94 X099, Ireland
- UCD
School of Medicine, College of Health and Agricultural Science (CHAS), University College Dublin (UCD), Dublin D04 PR94, Ireland
| | - Abhay Pandit
- SFI
Research Centre for Medical Devices (CÚRAM), National University of Ireland, Galway, Galway H91 W2TY, Ireland
| | - Siobhan S. McMahon
- SFI
Research Centre for Medical Devices (CÚRAM), National University of Ireland, Galway, Galway H91 W2TY, Ireland
- Discipline
of Anatomy, National University of Ireland, Galway H91 W5P7, Ireland
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Torruella-Gonzalez S, Slater PG, Lee-Liu D, Larraín J. Cornifelin expression during Xenopus laevis metamorphosis and in response to spinal cord injury. Gene Expr Patterns 2022; 43:119234. [DOI: 10.1016/j.gep.2022.119234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/25/2022] [Accepted: 02/06/2022] [Indexed: 11/17/2022]
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Reverdatto S, Prasad A, Belrose JL, Zhang X, Sammons MA, Gibbs KM, Szaro BG. Developmental and Injury-induced Changes in DNA Methylation in Regenerative versus Non-regenerative Regions of the Vertebrate Central Nervous System. BMC Genomics 2022; 23:2. [PMID: 34979916 PMCID: PMC8725369 DOI: 10.1186/s12864-021-08247-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 12/09/2021] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Because some of its CNS neurons (e.g., retinal ganglion cells after optic nerve crush (ONC)) regenerate axons throughout life, whereas others (e.g., hindbrain neurons after spinal cord injury (SCI)) lose this capacity as tadpoles metamorphose into frogs, the South African claw-toed frog, Xenopus laevis, offers unique opportunities for exploring differences between regenerative and non-regenerative responses to CNS injury within the same organism. An earlier, three-way RNA-seq study (frog ONC eye, tadpole SCI hindbrain, frog SCI hindbrain) identified genes that regulate chromatin accessibility among those that were differentially expressed in regenerative vs non-regenerative CNS [11]. The current study used whole genome bisulfite sequencing (WGBS) of DNA collected from these same animals at the peak period of axon regeneration to study the extent to which DNA methylation could potentially underlie differences in chromatin accessibility between regenerative and non-regenerative CNS. RESULTS Consistent with the hypothesis that DNA of regenerative CNS is more accessible than that of non-regenerative CNS, DNA from both the regenerative tadpole hindbrain and frog eye was less methylated than that of the non-regenerative frog hindbrain. Also, consistent with observations of CNS injury in mammals, DNA methylation in non-regenerative frog hindbrain decreased after SCI. However, contrary to expectations that the level of DNA methylation would decrease even further with axotomy in regenerative CNS, DNA methylation in these regions instead increased with injury. Injury-induced differences in CpG methylation in regenerative CNS became especially enriched in gene promoter regions, whereas non-CpG methylation differences were more evenly distributed across promoter regions, intergenic, and intragenic regions. In non-regenerative CNS, tissue-related (i.e., regenerative vs. non-regenerative CNS) and injury-induced decreases in promoter region CpG methylation were significantly correlated with increased RNA expression, but the injury-induced, increased CpG methylation seen in regenerative CNS across promoter regions was not, suggesting it was associated with increased rather than decreased chromatin accessibility. This hypothesis received support from observations that in regenerative CNS, many genes exhibiting increased, injury-induced, promoter-associated CpG-methylation also exhibited increased RNA expression and association with histone markers for active promoters and enhancers. DNA immunoprecipitation for 5hmC in optic nerve regeneration found that the promoter-associated increases seen in CpG methylation were distinct from those exhibiting changes in 5hmC. CONCLUSIONS Although seemingly paradoxical, the increased injury-associated DNA methylation seen in regenerative CNS has many parallels in stem cells and cancer. Thus, these axotomy-induced changes in DNA methylation in regenerative CNS provide evidence for a novel epigenetic state favoring successful over unsuccessful CNS axon regeneration. The datasets described in this study should help lay the foundations for future studies of the molecular and cellular mechanisms involved. The insights gained should, in turn, help point the way to novel therapeutic approaches for treating CNS injury in mammals.
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Affiliation(s)
- Sergei Reverdatto
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, 12222, USA
- Center for Neuroscience Research, University at Albany, State University of New York, Albany, NY, 12222, USA
- RNA Institute, University at Albany, State University of New York, Albany, NY, 12222, USA
| | - Aparna Prasad
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, 12222, USA
- Center for Neuroscience Research, University at Albany, State University of New York, Albany, NY, 12222, USA
- RNA Institute, University at Albany, State University of New York, Albany, NY, 12222, USA
| | - Jamie L Belrose
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, 12222, USA
- Center for Neuroscience Research, University at Albany, State University of New York, Albany, NY, 12222, USA
| | - Xiang Zhang
- Department of Environmental and Public Health Sciences, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Morgan A Sammons
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, 12222, USA
- RNA Institute, University at Albany, State University of New York, Albany, NY, 12222, USA
| | - Kurt M Gibbs
- Department of Biology & Chemistry, Morehead State University, Morehead, KY, 40351, USA
| | - Ben G Szaro
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY, 12222, USA.
- Center for Neuroscience Research, University at Albany, State University of New York, Albany, NY, 12222, USA.
- RNA Institute, University at Albany, State University of New York, Albany, NY, 12222, USA.
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Alibardi L. Growth associated protein 43 and neurofilament immunolabeling in the transected lumbar spinal cord of lizard indicates limited axonal regeneration. Neural Regen Res 2021; 17:1034-1041. [PMID: 34558530 PMCID: PMC8552833 DOI: 10.4103/1673-5374.324850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Previous cytological studies on the transected lumbar spinal cord of lizards have shown the presence of differentiating glial cells, few neurons and axons in the bridge region between the proximal and distal stumps of the spinal cord in some cases. A limited number of axons (20–50) can cross the bridge and re-connect the caudal stump of the spinal cord with small neurons located in the rostral stump of the spinal cord. This axonal regeneration appears to be related to the recovery of hind-limb movements after initial paralysis. The present study extends previous studies and shows that after transection of the lumbar spinal cord in lizards, a glial-connective tissue bridge that reconnects the rostral and caudal stumps of the interrupted spinal cord is formed at 11–34 days post-injury. Following an initial paralysis some recovery of hindlimb movements occurs within 1–3 months post-injury. Immunohistochemical and ultrastructural analysis for a growth associated protein 43 (GAP-43) of 48–50 kDa shows that sparse GAP-43 positive axons are present in the proximal stump of the spinal cord but their number decreased in the bridge at 11–34 days post-transection. Few immunolabeled axons with a neurofilament protein of 200–220 kDa were seen in the bridge at 11–22 days post-transection but their number increased at 34 days and 3 months post-amputation in lizards that have recovered some hindlimb movements. Numerous neurons in the rostral and caudal stumps of the spinal cord were also labeled for GAP43, a cytoplasmic protein that is trans-located into their axonal growth cones. This indicates that GAP-43 biosynthesis is related to axonal regeneration and sprouting from neurons that were damaged by the transection. Taken together, previous studies that utilized tract-tracing technique to label the present observations confirm that a limited axonal re-connection of the transected spinal cord occurs 1–3 months post-injury in lizards. The few regenerating-sprouting axons within the bridge reconnect the caudal with the rostral stumps of the spinal cord, and likely contribute to activate the neural circuits that sustain the limited but important recovery of hind-limb movements after initial paralysis. The surgical procedures utilized in the study followed the regulations on animal care and experimental procedures under the Italian Guidelines (art. 5, DL 116/92).
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Affiliation(s)
- Lorenzo Alibardi
- Comparative Histolab Padova and Department of Biology, University of Bologna, Bologna, Italy
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Edwards-Faret G, González-Pinto K, Cebrián-Silla A, Peñailillo J, García-Verdugo JM, Larraín J. Cellular response to spinal cord injury in regenerative and non-regenerative stages in Xenopus laevis. Neural Dev 2021; 16:2. [PMID: 33526076 PMCID: PMC7852093 DOI: 10.1186/s13064-021-00152-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 01/14/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The efficient regenerative abilities at larvae stages followed by a non-regenerative response after metamorphosis in froglets makes Xenopus an ideal model organism to understand the cellular responses leading to spinal cord regeneration. METHODS We compared the cellular response to spinal cord injury between the regenerative and non-regenerative stages of Xenopus laevis. For this analysis, we used electron microscopy, immunofluorescence and histological staining of the extracellular matrix. We generated two transgenic lines: i) the reporter line with the zebrafish GFAP regulatory regions driving the expression of EGFP, and ii) a cell specific inducible ablation line with the same GFAP regulatory regions. In addition, we used FACS to isolate EGFP+ cells for RNAseq analysis. RESULTS In regenerative stage animals, spinal cord regeneration triggers a rapid sealing of the injured stumps, followed by proliferation of cells lining the central canal, and formation of rosette-like structures in the ablation gap. In addition, the central canal is filled by cells with similar morphology to the cells lining the central canal, neurons, axons, and even synaptic structures. Regeneration is almost completed after 20 days post injury. In non-regenerative stage animals, mostly damaged tissue was observed, without clear closure of the stumps. The ablation gap was filled with fibroblast-like cells, and deposition of extracellular matrix components. No reconstruction of the spinal cord was observed even after 40 days post injury. Cellular markers analysis confirmed these histological differences, a transient increase of vimentin, fibronectin and collagen was detected in regenerative stages, contrary to a sustained accumulation of most of these markers, including chondroitin sulfate proteoglycans in the NR-stage. The zebrafish GFAP transgenic line was validated, and we have demonstrated that is a very reliable and new tool to study the role of neural stem progenitor cells (NSPCs). RNASeq of GFAP::EGFP cells has allowed us to clearly demonstrate that indeed these cells are NSPCs. On the contrary, the GFAP::EGFP transgene is mainly expressed in astrocytes in non-regenerative stages. During regenerative stages, spinal cord injury activates proliferation of NSPCs, and we found that are mainly differentiated into neurons and glial cells. Specific ablation of these cells abolished proper regeneration, confirming that NSPCs cells are necessary for functional regeneration of the spinal cord. CONCLUSIONS The cellular response to spinal cord injury in regenerative and non-regenerative stages is profoundly different between both stages. A key hallmark of the regenerative response is the activation of NSPCs, which massively proliferate, and are differentiated into neurons to reconstruct the spinal cord. Also very notably, no glial scar formation is observed in regenerative stages, but a transient, glial scar-like structure is formed in non-regenerative stage animals.
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Affiliation(s)
- Gabriela Edwards-Faret
- Center for Aging and Regeneration, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Karina González-Pinto
- Center for Aging and Regeneration, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Arantxa Cebrián-Silla
- Laboratorio de Neurobiología Comparada, Instituto Cavanilles, Universidad de Valencia, CIBERNED, 46980, Valencia, Spain
| | - Johany Peñailillo
- Center for Aging and Regeneration, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - José Manuel García-Verdugo
- Laboratorio de Neurobiología Comparada, Instituto Cavanilles, Universidad de Valencia, CIBERNED, 46980, Valencia, Spain
| | - Juan Larraín
- Center for Aging and Regeneration, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.
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6
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Alibardi L. NOGO-A immunolabeling is present in glial cells and some neurons of the recovering lumbar spinal cord in lizards. J Morphol 2020; 281:1260-1270. [PMID: 32770765 DOI: 10.1002/jmor.21245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/07/2020] [Accepted: 07/19/2020] [Indexed: 12/13/2022]
Abstract
The transected lumbar spinal cord of lizards was studied for its ability to recover after paralysis. At 34 days post-lesion about 50% of lizards were capable of walking with a limited coordination, likely due to the regeneration of few connecting axons crossing the transection site of the spinal cord. This region, indicated as "bridge", contains glial cells among which oligodendrocytes and their elongation that are immunolabeled for NOGO-A. A main reactive protein band occurs at 100-110 kDa but a weaker band is also observed around 240 kDa, suggesting fragmentation of the native protein due to extraction or to physiological processing of the original protein. Most of the cytoplasmic immunolabeling observed in oligodendrocytes is associated with vesicles of the endoplasmic reticulum. Also, the nucleus is labeled in some oligodendrocytes that are myelinating sparse axons observed within the bridge at 22-34 days post-transection. This suggests that axonal regeneration is present within the bridge region. Immunolabeling for NOGO-A shows that the protein is also present in numerous reactive neurons, in particular motor-neurons localized in the proximal stump of the transected spinal cord. Ultrastructural immunolocalization suggests that NOGO is synthesized in the ribosomes of these neurons and becomes associated with the cisternae of the endoplasmic reticulum, probably following a secretory pathway addressed toward the axon. The present observations suggest that, like for the regenerating spinal cord of fish and amphibians, also in lizard NOGO-A is present in reactive neurons and appears associated to axonal regeneration and myelination.
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Affiliation(s)
- Lorenzo Alibardi
- Comparative Histolab Padova and Department of Biology, University of Bologna, Bologna, Italy
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7
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Belrose JL, Prasad A, Sammons MA, Gibbs KM, Szaro BG. Comparative gene expression profiling between optic nerve and spinal cord injury in Xenopus laevis reveals a core set of genes inherent in successful regeneration of vertebrate central nervous system axons. BMC Genomics 2020; 21:540. [PMID: 32758133 PMCID: PMC7430912 DOI: 10.1186/s12864-020-06954-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 07/27/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The South African claw-toed frog, Xenopus laevis, is uniquely suited for studying differences between regenerative and non-regenerative responses to CNS injury within the same organism, because some CNS neurons (e.g., retinal ganglion cells after optic nerve crush (ONC)) regenerate axons throughout life, whereas others (e.g., hindbrain neurons after spinal cord injury (SCI)) lose this capacity as tadpoles metamorphose into frogs. Tissues from these CNS regions (frog ONC eye, tadpole SCI hindbrain, frog SCI hindbrain) were used in a three-way RNA-seq study of axotomized CNS axons to identify potential core gene expression programs for successful CNS axon regeneration. RESULTS Despite tissue-specific changes in expression dominating the injury responses of each tissue, injury-induced changes in gene expression were nonetheless shared between the two axon-regenerative CNS regions that were not shared with the non-regenerative region. These included similar temporal patterns of gene expression and over 300 injury-responsive genes. Many of these genes and their associated cellular functions had previously been associated with injury responses of multiple tissues, both neural and non-neural, from different species, thereby demonstrating deep phylogenetically conserved commonalities between successful CNS axon regeneration and tissue regeneration in general. Further analyses implicated the KEGG adipocytokine signaling pathway, which links leptin with metabolic and gene regulatory pathways, and a novel gene regulatory network with genes regulating chromatin accessibility at its core, as important hubs in the larger network of injury response genes involved in successful CNS axon regeneration. CONCLUSIONS This study identifies deep, phylogenetically conserved commonalities between CNS axon regeneration and other examples of successful tissue regeneration and provides new targets for studying the molecular underpinnings of successful CNS axon regeneration, as well as a guide for distinguishing pro-regenerative injury-induced changes in gene expression from detrimental ones in mammals.
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Affiliation(s)
- Jamie L Belrose
- Department of Biological Sciences, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
- Center for Neuroscience Research, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Aparna Prasad
- Department of Biological Sciences, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
- Center for Neuroscience Research, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Morgan A Sammons
- Department of Biological Sciences, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Kurt M Gibbs
- Department of Biology and Chemistry, Morehead State University, Morehead, KY, 40351, USA
| | - Ben G Szaro
- Department of Biological Sciences, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA.
- Center for Neuroscience Research, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY, 12222, USA.
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Anguita-Salinas C, Sánchez M, Morales RA, Ceci ML, Rojas-Benítez D, Allende ML. Cellular Dynamics during Spinal Cord Regeneration in Larval Zebrafish. Dev Neurosci 2019; 41:112-122. [PMID: 31390621 DOI: 10.1159/000500185] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 04/04/2019] [Indexed: 11/19/2022] Open
Abstract
The study of spinal cord regeneration using diverse animal models, which range from null to robust regenerative capabilities, is imperative for understanding how regeneration evolved and, eventually, to treat spinal cord injury and paralysis in humans. In this study, we used electroablation to fully transect the spinal cord of zebrafish larvae (3 days postfertilization) and examined regeneration of the tissue over time. We used transgenic lines to follow immune cells, oligodendrocytes, and neurons in vivo during the entire regenerative process. We observed that immune cells are recruited to the injury site, oligodendrocytes progenitor cells (olig2-expressing cells) invade, and axons cross the gap generated upon damage from anterior to reinnervate caudal structures. Together with the recovery of cell types and structures, a complete reversal of paralysis was observed in the lesioned larvae indicating functional regeneration. Finally, using transplantation to obtain mosaic larvae with single-labeled neurons, we show that severed spinal axons exhibited varying regenerative capabilities and plasticity depending on their original dorsoventral position in the spinal cord.
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Affiliation(s)
- Consuelo Anguita-Salinas
- FONDAP Center for Genome Regulation, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Mario Sánchez
- FONDAP Center for Genome Regulation, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Rodrigo A Morales
- FONDAP Center for Genome Regulation, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - María Laura Ceci
- FONDAP Center for Genome Regulation, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Diego Rojas-Benítez
- FONDAP Center for Genome Regulation, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Miguel L Allende
- FONDAP Center for Genome Regulation, Facultad de Ciencias, Universidad de Chile, Santiago, Chile,
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Sabin KZ, Jiang P, Gearhart MD, Stewart R, Echeverri K. AP-1 cFos/JunB/miR-200a regulate the pro-regenerative glial cell response during axolotl spinal cord regeneration. Commun Biol 2019; 2:91. [PMID: 30854483 PMCID: PMC6403268 DOI: 10.1038/s42003-019-0335-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 02/04/2019] [Indexed: 12/30/2022] Open
Abstract
Salamanders have the remarkable ability to functionally regenerate after spinal cord transection. In response to injury, GFAP+ glial cells in the axolotl spinal cord proliferate and migrate to replace the missing neural tube and create a permissive environment for axon regeneration. Molecular pathways that regulate the pro-regenerative axolotl glial cell response are poorly understood. Here we show axolotl glial cells up-regulate AP-1cFos/JunB after injury, which promotes a pro-regenerative glial cell response. Injury induced upregulation of miR-200a in glial cells supresses c-Jun expression in these cells. Inhibition of miR-200a during regeneration causes defects in axonal regrowth and transcriptomic analysis revealed that miR-200a inhibition leads to differential regulation of genes involved with reactive gliosis, the glial scar, extracellular matrix remodeling and axon guidance. This work identifies a unique role for miR-200a in inhibiting reactive gliosis in axolotl glial cells during spinal cord regeneration. Keith Sabin et al. showed that upregulation of the AP-1 complex, composed of c-Fos and JunB, in the axolotl spinal cord promotes a pro-regenerative glial cell response. This response is impaired by inhibition of miR-200a; suggesting an important role for this microRNA in axolotl spinal cord regeneration.
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Affiliation(s)
- Keith Z Sabin
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, 55455, USA.,Marine Biological Laboratory, Eugene Bell Center for Regenerative Biology and Tissue Engineering, Woods Hole, 02543, MA, USA
| | - Peng Jiang
- Morgridge Institute for Research, Madison, 53715, WI, USA
| | - Micah D Gearhart
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Ron Stewart
- Morgridge Institute for Research, Madison, 53715, WI, USA
| | - Karen Echeverri
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, 55455, USA. .,Marine Biological Laboratory, Eugene Bell Center for Regenerative Biology and Tissue Engineering, Woods Hole, 02543, MA, USA.
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10
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Freitas PD, Yandulskaya AS, Monaghan JR. Spinal Cord Regeneration in Amphibians: A Historical Perspective. Dev Neurobiol 2019; 79:437-452. [PMID: 30725532 DOI: 10.1002/dneu.22669] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 01/22/2019] [Accepted: 01/25/2019] [Indexed: 12/11/2022]
Abstract
In some vertebrates, a grave injury to the central nervous system (CNS) results in functional restoration, rather than in permanent incapacitation. Understanding how these animals mount a regenerative response by activating resident CNS stem cell populations is of critical importance in regenerative biology. Amphibians are of a particular interest in the field because the regenerative ability is present throughout life in urodele species, but in anuran species it is lost during development. Studying amphibians, who transition from a regenerative to a nonregenerative state, could give insight into the loss of ability to recover from CNS damage in mammals. Here, we highlight the current knowledge of spinal cord regeneration across vertebrates and identify commonalities and differences in spinal cord regeneration between amphibians.
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Affiliation(s)
- Polina D Freitas
- Department of Biology, Northeastern University, 360 Huntington Ave., 134 Mugar Hall, Boston, Massachusetts, 02115
| | - Anastasia S Yandulskaya
- Department of Biology, Northeastern University, 360 Huntington Ave., 134 Mugar Hall, Boston, Massachusetts, 02115
| | - James R Monaghan
- Department of Biology, Northeastern University, 360 Huntington Ave., 134 Mugar Hall, Boston, Massachusetts, 02115
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11
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Méndez-Olivos EE, Larraín J. Cell Transplantation as a Method to Investigate Spinal Cord Regeneration in Regenerative and Nonregenerative Xenopus Stages. Cold Spring Harb Protoc 2018; 2018:pdb.prot101006. [PMID: 29769390 DOI: 10.1101/pdb.prot101006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Mammals are not capable of regenerating their central nervous system (CNS); anamniotes, however, can regenerate in response to injury. The mechanisms that explain the different regenerative capabilities include: (i) extrinsic mechanisms that consider the cellular environment and extracellular matrix composition, (ii) intrinsic factors implicating the presence or absence of genetic programs that promote axon regeneration, and (iii) the presence or absence of neural stem and progenitors cells (NSPCs) that allow neurogenesis. Xenopus laevis is able to regenerate its CNS during larval stages (i.e., the regenerative stage [R-stage]). However, concomitant with metamorphosis this capacity decreases and is lost completely in juvenile froglets (i.e., nonregenerative stages [NR-stages]). The loss of the regenerative ability correlates with a reduction in the percentage of Sox2+ cells, which are putative NSPCs. This protocol shows the effect of transplantation of spinal cord cells from R-stage Xenopus larvae into NR-stage froglets. Using this procedure, it is possible to study axon regeneration and stem cell biology in vivo.
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Affiliation(s)
- Emilio E Méndez-Olivos
- Center for Aging and Regeneration, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Juan Larraín
- Center for Aging and Regeneration, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile
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Gibbs KM, Szaro BG. Tracing Central Nervous System Axon Regeneration in Xenopus. Cold Spring Harb Protoc 2018; 2018:pdb.prot101030. [PMID: 29769393 DOI: 10.1101/pdb.prot101030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Axonal tracing allows visualizing connectivity between neurons, providing useful information about structure, neuronal location, and function of the nervous system. Identifying regenerating axons and their neuron cell bodies present the particular challenges of labeling the projections of interest while unambiguously demonstrating regrowth of those axons that have been damaged. In the developing brain, an additional labeling challenge arises, as new connections are being made throughout the duration of an experiment. Various strategies have been used to label regenerating axons, including transgenic animals expressing neuron-specific fluorescent proteins, and application of a single labeling molecule after axotomy and regeneration. However, the single label approach is limited in its application to the developing brain, primarily because it leads to the conclusion that every axon that is labeled has regenerated. Double-labeling overcomes these obstacles by identifying regenerating cells as those that are labeled with two different tracing molecules. Moreover, the use of dextran amines, which are only taken up by injured axons and transported retrogradely, provides further confidence of labeling regenerating axons and neuron cell bodies. The procedure described herein provides a straightforward method for using fluorescently labeled dextran amines to identify regenerating supraspinal neurons in Xenopus, but can be applied to other areas of the central and peripheral nervous system as well.
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Affiliation(s)
- Kurt M Gibbs
- Department of Biology & Chemistry, Morehead State University, Morehead, Kentucky 40351
| | - Ben G Szaro
- Department of Biological Sciences, State University of New York at Albany, Albany, New York 12222
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Luttrell SM, Su YH, Swalla BJ. Getting a Head with Ptychodera flava Larval Regeneration. THE BIOLOGICAL BULLETIN 2018; 234:152-164. [PMID: 29949438 DOI: 10.1086/698510] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Severe injury to the central nervous system of chordates often results in permanent and irreversible mental and physical challenges. While some chordates are able to repair and/or regenerate portions of their nervous system, no chordate has been shown to be able to regenerate all regions of its central nervous system after catastrophic injury or amputation. Some hemichordates, on the other hand, are able to efficiently regenerate all neural structures, including their dorsal, hollow neural tube after complete ablation. Solitary hemichordates are marine acorn worms and a sister group to the echinoderms. The hemichordate Ptychodera flava progresses from a pelagic, feeding tornaria larva to a tripartite benthic worm with an anterior proboscis, a middle collar region, and a long posterior trunk. The adult worm regenerates all body parts when bisected in the trunk, but it was unknown whether the regeneration process was present in tornaria larvae. Now, we show that P. flava larvae are capable of robust regeneration after bisection through the sagittal, coronal, and axial planes. We also use antibody staining to show that the apical sensory organ regenerates a rich, serotonin-positive complex of cells within two weeks after amputation. Cells labeled with 5-ethynyl-2'-deoxyuridine confirm that regeneration is occurring through epimorphic processes as new cells are added at the cut site and throughout the regenerating tissue. This study verifies that P. flava larvae can be used for future functional studies aimed at identifying the genetic and morphological mechanisms controlling central nervous system regeneration in a stem deuterostome.
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Edwards-Faret G, Cebrián-Silla A, Méndez-Olivos EE, González-Pinto K, García-Verdugo JM, Larraín J. Cellular composition and organization of the spinal cord central canal during metamorphosis of the frog Xenopus laevis. J Comp Neurol 2018; 526:1712-1732. [PMID: 29603210 DOI: 10.1002/cne.24441] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 03/12/2018] [Accepted: 03/21/2018] [Indexed: 01/12/2023]
Abstract
Studying the cellular composition and morphological changes of cells lining the central canal during Xenopus laevis metamorphosis could contribute to understand postnatal development and spinal cord regeneration. Here we report the analysis of central canal cells at different stages during metamorphosis using immunofluorescence for protein markers expression, transmission and scanning electron microscopy and cell proliferation assays. The central canal was regionalized according to expression of glial markers, ultrastructure, and proliferation in dorsal, lateral, and ventral domains with differences between larvae and froglets. In regenerative larvae, all cell types were uniciliated, have a radial morphology, and elongated nuclei with lax chromatin, resembling radial glial cells. Important differences in cells of nonregenerative froglets were observed, although uniciliated cells were found, the most abundant cells had multicilia and revealed extensive changes in the maturation and differentiation state. The majority of dividing cells in larvae corresponded to uniciliated cells at dorsal and lateral domains in a cervical-lumbar gradient, correlating with undifferentiated features. Neurons contacting the lumen of the central canal were detected in both stages and revealed extensive changes in the maturation and differentiation state. However, in froglets a very low proportion of cells incorporate 5-ethynyl-2'-deoxyuridine (EdU), associated with the differentiated profile and with the increase of multiciliated cells. Our work showed progressive changes in the cell types lining the central canal of Xenopus laevis spinal cord which are correlated with the regenerative capacities.
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Affiliation(s)
- Gabriela Edwards-Faret
- Center for Aging and Regeneration, Faculty of Biological Sciences, P. Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Arantxa Cebrián-Silla
- Laboratorio de Neurobiologia Comparada, Instituto Cavanilles, Universidad de Valencia, Valencia 46980, CIBERNED, Valencia, Spain
| | - Emilio E Méndez-Olivos
- Center for Aging and Regeneration, Faculty of Biological Sciences, P. Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Karina González-Pinto
- Center for Aging and Regeneration, Faculty of Biological Sciences, P. Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile.,Universidad Arturo Prat del Estado de Chile, Iquique, Chile
| | - José Manuel García-Verdugo
- Laboratorio de Neurobiologia Comparada, Instituto Cavanilles, Universidad de Valencia, Valencia 46980, CIBERNED, Valencia, Spain
| | - Juan Larraín
- Center for Aging and Regeneration, Faculty of Biological Sciences, P. Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile
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Chernoff EAG, Sato K, Salfity HVN, Sarria DA, Belecky-Adams T. Musashi and Plasticity of Xenopus and Axolotl Spinal Cord Ependymal Cells. Front Cell Neurosci 2018. [PMID: 29535610 PMCID: PMC5835034 DOI: 10.3389/fncel.2018.00045] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The differentiated state of spinal cord ependymal cells in regeneration-competent amphibians varies between a constitutively active state in what is essentially a developing organism, the tadpole of the frog Xenopus laevis, and a quiescent, activatable state in a slowly growing adult salamander Ambystoma mexicanum, the Axolotl. Ependymal cells are epithelial in intact spinal cord of all vertebrates. After transection, body region ependymal epithelium in both Xenopus and the Axolotl disorganizes for regenerative outgrowth (gap replacement). Injury-reactive ependymal cells serve as a stem/progenitor cell population in regeneration and reconstruct the central canal. Expression patterns of mRNA and protein for the stem/progenitor cell-maintenance Notch signaling pathway mRNA-binding protein Musashi (msi) change with life stage and regeneration competence. Msi-1 is missing (immunohistochemistry), or at very low levels (polymerase chain reaction, PCR), in both intact regeneration-competent adult Axolotl cord and intact non-regeneration-competent Xenopus tadpole (Nieuwkoop and Faber stage 62+, NF 62+). The critical correlation for successful regeneration is msi-1 expression/upregulation after injury in the ependymal outgrowth and stump-region ependymal cells. msi-1 and msi-2 isoforms were cloned for the Axolotl as well as previously unknown isoforms of Xenopus msi-2. Intact Xenopus spinal cord ependymal cells show a loss of msi-1 expression between regeneration-competent (NF 50-53) and non-regenerating stages (NF 62+) and in post-metamorphosis froglets, while msi-2 displays a lower molecular weight isoform in non-regenerating cord. In the Axolotl, embryos and juveniles maintain Msi-1 expression in the intact cord. In the adult Axolotl, Msi-1 is absent, but upregulates after injury. Msi-2 levels are more variable among Axolotl life stages: rising between late tailbud embryos and juveniles and decreasing in adult cord. Cultures of regeneration-competent Xenopus tadpole cord and injury-responsive adult Axolotl cord ependymal cells showed an identical growth factor response. Epidermal growth factor (EGF) maintains mesenchymal outgrowth in vitro, the cells are proliferative and maintain msi-1 expression. Non-regeneration competent Xenopus ependymal cells, NF 62+, failed to attach or grow well in EGF+ medium. Ependymal Msi-1 expression in vivo and in vitro is a strong indicator of regeneration competence in the amphibian spinal cord.
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Affiliation(s)
- Ellen A G Chernoff
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Kazuna Sato
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Hai V N Salfity
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Deborah A Sarria
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Teri Belecky-Adams
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
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Méndez-Olivos EE, Muñoz R, Larraín J. Spinal Cord Cells from Pre-metamorphic Stages Differentiate into Neurons and Promote Axon Growth and Regeneration after Transplantation into the Injured Spinal Cord of Non-regenerative Xenopus laevis Froglets. Front Cell Neurosci 2017; 11:398. [PMID: 29326551 PMCID: PMC5733487 DOI: 10.3389/fncel.2017.00398] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 11/28/2017] [Indexed: 11/13/2022] Open
Abstract
Mammals are unable to regenerate its spinal cord after a lesion, meanwhile, anuran amphibians are capable of spinal cord regeneration only as larvae, and during metamorphosis, this capability is lost. Sox2/3+ cells present in the spinal cord of regenerative larvae are required for spinal cord regeneration. Here we evaluate the effect of the transplantation of spinal cord cells from regenerative larvae into the resected spinal cord of non-regenerative stages (NR-stage). Donor cells were able to survive up to 60 days after transplantation in the injury zone. During the first 3-weeks, transplanted cells organize in neural tube-like structures formed by Sox2/3+ cells. This was not observed when donor cells come from non-regenerative froglets. Mature neurons expressing NeuN and Neurofilament-H were detected in the grafted tissue 4 weeks after transplantation concomitantly with the appearance of axons derived from the donor cells growing into the host spinal cord, suggesting that Sox2/3+ cells behave as neural stem progenitor cells. We also found that cells from regenerative animals provide a permissive environment that promotes growth and regeneration of axons coming from the host. These results suggest that Sox2/3 cells present in the spinal cord of regenerative stage (R-stage) larvae are most probably neural stem progenitor cells that are able to survive, proliferate, self-organize and differentiate into neurons in the environment of the non-regenerative host. In addition, we have established an experimental paradigm to study the biology of neural stem progenitor cells in spinal cord regeneration.
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Affiliation(s)
- Emilio E Méndez-Olivos
- Center for Aging and Regeneration, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Rosana Muñoz
- Center for Aging and Regeneration, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan Larraín
- Center for Aging and Regeneration, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
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Tapia VS, Herrera‐Rojas M, Larrain J. JAK-STAT pathway activation in response to spinal cord injury in regenerative and non-regenerative stages of Xenopus laevis. REGENERATION (OXFORD, ENGLAND) 2017; 4:21-35. [PMID: 28316792 PMCID: PMC5350081 DOI: 10.1002/reg2.74] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 01/17/2017] [Accepted: 01/18/2017] [Indexed: 12/13/2022]
Abstract
Xenopus laevis tadpoles can regenerate the spinal cord after injury but this capability is lost during metamorphosis. Comparative studies between pre-metamorphic and metamorphic Xenopus stages can aid towards understanding the molecular mechanisms of spinal cord regeneration. Analysis of a previous transcriptome-wide study suggests that, in response to injury, the JAK-STAT pathway is differentially activated in regenerative and non-regenerative stages. We characterized the activation of the JAK-STAT pathway and found that regenerative tadpoles have an early and transient activation. In contrast, the non-regenerative stages have a delayed and sustained activation of the pathway. We found that STAT3 is activated in response to injury mainly in Sox2/3+ ependymal cells, motoneurons and sensory neurons. Finally, to study the role of temporal activation we generated a transgenic line to express a constitutively active version of STAT3. The sustained activation of the JAK-STAT pathway in regenerative tadpoles reduced the expression of pro-neurogenic genes normally upregulated in response to spinal cord injury, suggesting that activation of the JAK-STAT pathway modulates the fate of neural progenitors.
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Affiliation(s)
- Victor S. Tapia
- Center for Aging and RegenerationMillennium Nucleus in Regenerative BiologyFacultad de Ciencias BiologicasPontificia Universidad Catolica de ChileSantiagoChile
| | - Mauricio Herrera‐Rojas
- Center for Aging and RegenerationMillennium Nucleus in Regenerative BiologyFacultad de Ciencias BiologicasPontificia Universidad Catolica de ChileSantiagoChile
| | - Juan Larrain
- Center for Aging and RegenerationMillennium Nucleus in Regenerative BiologyFacultad de Ciencias BiologicasPontificia Universidad Catolica de ChileSantiagoChile
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18
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Edwards-Faret G, Muñoz R, Méndez-Olivos EE, Lee-Liu D, Tapia VS, Larraín J. Spinal cord regeneration in Xenopus laevis. Nat Protoc 2017; 12:372-389. [PMID: 28102835 DOI: 10.1038/nprot.2016.177] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Here we present a protocol for the husbandry of Xenopus laevis tadpoles and froglets, and procedures to study spinal cord regeneration. This includes methods to induce spinal cord injury (SCI); DNA and morpholino electroporation for genetic studies; in vivo imaging for cell analysis; a swimming test to measure functional recovery; and a convenient model for screening for new compounds that promote neural regeneration. These protocols establish X. laevis as a unique model organism for understanding spinal cord regeneration by comparing regenerative and nonregenerative stages. This protocol can be used to understand the molecular and cellular mechanisms involved in nervous system regeneration, including neural stem and progenitor cell (NSPC) proliferation and neurogenesis, extrinsic and intrinsic mechanisms involved in axon regeneration, glial response and scar formation, and trophic factors. For experienced personnel, husbandry takes 1-2 months; SCI can be achieved in 5-15 min; and swimming recovery takes 20-30 d.
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Affiliation(s)
- Gabriela Edwards-Faret
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Rosana Muñoz
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Emilio E Méndez-Olivos
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Dasfne Lee-Liu
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Victor S Tapia
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan Larraín
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
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Lee-Liu D, Méndez-Olivos EE, Muñoz R, Larraín J. The African clawed frog Xenopus laevis: A model organism to study regeneration of the central nervous system. Neurosci Lett 2016; 652:82-93. [PMID: 27693567 DOI: 10.1016/j.neulet.2016.09.054] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 09/18/2016] [Accepted: 09/28/2016] [Indexed: 12/20/2022]
Abstract
While an injury to the central nervous system (CNS) in humans and mammals is irreversible, amphibians and teleost fish have the capacity to fully regenerate after severe injury to the CNS. Xenopus laevis has a high potential to regenerate the brain and spinal cord during larval stages (47-54), and loses this capacity during metamorphosis. The optic nerve has the capacity to regenerate throughout the frog's lifespan. Here, we review CNS regeneration in frogs, with a focus in X. laevis, but also provide some information about X. tropicalis and other frogs. We start with an overview of the anatomy of the Xenopus CNS, including the main supraspinal tracts that emerge from the brain stem, which play a key role in motor control and are highly conserved across vertebrates. We follow with the advantages of using Xenopus, a classical laboratory model organism, with increasing availability of genetic tools like transgenesis and genome editing, and genomic sequences for both X. laevis and X. tropicalis. Most importantly, Xenopus provides the possibility to perform intra-species comparative experiments between regenerative and non-regenerative stages that allow the identification of which factors are permissive for neural regeneration, and/or which are inhibitory. We aim to provide sufficient evidence supporting how useful Xenopus can be to obtain insights into our understanding of CNS regeneration, which, complemented with studies in mammalian vertebrate model systems, can provide a collaborative road towards finding novel therapeutic approaches for injuries to the CNS.
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Affiliation(s)
- Dasfne Lee-Liu
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, P. Universidad Católica de Chile, Alameda 340, Santiago, Chile.
| | - Emilio E Méndez-Olivos
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, P. Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Rosana Muñoz
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, P. Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Juan Larraín
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, P. Universidad Católica de Chile, Alameda 340, Santiago, Chile.
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20
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Faunes F, Larraín J. Conservation in the involvement of heterochronic genes and hormones during developmental transitions. Dev Biol 2016; 416:3-17. [DOI: 10.1016/j.ydbio.2016.06.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 06/03/2016] [Accepted: 06/09/2016] [Indexed: 01/26/2023]
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Ghosh S, Hui SP. Regeneration of Zebrafish CNS: Adult Neurogenesis. Neural Plast 2016; 2016:5815439. [PMID: 27382491 PMCID: PMC4921647 DOI: 10.1155/2016/5815439] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/18/2016] [Indexed: 12/13/2022] Open
Abstract
Regeneration in the animal kingdom is one of the most fascinating problems that have allowed scientists to address many issues of fundamental importance in basic biology. However, we came to know that the regenerative capability may vary across different species. Among vertebrates, fish and amphibians are capable of regenerating a variety of complex organs through epimorphosis. Zebrafish is an excellent animal model, which can repair several organs like damaged retina, severed spinal cord, injured brain and heart, and amputated fins. The focus of the present paper is on spinal cord regeneration in adult zebrafish. We intend to discuss our current understanding of the cellular and molecular mechanism(s) that allows formation of proliferating progenitors and controls neurogenesis, which involve changes in epigenetic and transcription programs. Unlike mammals, zebrafish retains radial glia, a nonneuronal cell type in their adult central nervous system. Injury induced proliferation involves radial glia which proliferate, transcribe embryonic genes, and can give rise to new neurons. Recent technological development of exquisite molecular tools in zebrafish, such as cell ablation, lineage analysis, and novel and substantial microarray, together with advancement in stem cell biology, allowed us to investigate how progenitor cells contribute to the generation of appropriate structures and various underlying mechanisms like reprogramming.
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Affiliation(s)
- Sukla Ghosh
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, 92 A. P. C. Road, Kolkata 700009, India
| | - Subhra Prakash Hui
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, 92 A. P. C. Road, Kolkata 700009, India
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Muñoz R, Edwards-Faret G, Moreno M, Zuñiga N, Cline H, Larraín J. Regeneration of Xenopus laevis spinal cord requires Sox2/3 expressing cells. Dev Biol 2015; 408:229-43. [PMID: 25797152 DOI: 10.1016/j.ydbio.2015.03.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 02/06/2015] [Accepted: 03/11/2015] [Indexed: 11/30/2022]
Abstract
Spinal cord regeneration is very inefficient in humans, causing paraplegia and quadriplegia. Studying model organisms that can regenerate the spinal cord in response to injury could be useful for understanding the cellular and molecular mechanisms that explain why this process fails in humans. Here, we use Xenopus laevis as a model organism to study spinal cord repair. Histological and functional analyses showed that larvae at pre-metamorphic stages restore anatomical continuity of the spinal cord and recover swimming after complete spinal cord transection. These regenerative capabilities decrease with onset of metamorphosis. The ability to study regenerative and non-regenerative stages in Xenopus laevis makes it a unique model system to study regeneration. We studied the response of Sox2(/)3 expressing cells to spinal cord injury and their function in the regenerative process. We found that cells expressing Sox2 and/or Sox3 are present in the ventricular zone of regenerative animals and decrease in non-regenerative froglets. Bromodeoxyuridine (BrdU) experiments and in vivo time-lapse imaging studies using green fluorescent protein (GFP) expression driven by the Sox3 promoter showed a rapid, transient and massive proliferation of Sox2(/)3(+) cells in response to injury in the regenerative stages. The in vivo imaging also demonstrated that Sox2(/)3(+) neural progenitor cells generate neurons in response to injury. In contrast, these cells showed a delayed and very limited response in non-regenerative froglets. Sox2 knockdown and overexpression of a dominant negative form of Sox2 disrupts locomotor and anatomical-histological recovery. We also found that neurogenesis markers increase in response to injury in regenerative but not in non-regenerative animals. We conclude that Sox2 is necessary for spinal cord regeneration and suggest a model whereby spinal cord injury activates proliferation of Sox2/3 expressing cells and their differentiation into neurons, a mechanism that is lost in non-regenerative froglets.
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Affiliation(s)
- Rosana Muñoz
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, P. Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Gabriela Edwards-Faret
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, P. Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Mauricio Moreno
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, P. Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Nikole Zuñiga
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, P. Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Hollis Cline
- The Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, United States
| | - Juan Larraín
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, P. Universidad Católica de Chile, Alameda 340, Santiago, Chile.
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23
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Lee-Liu D, Moreno M, Almonacid LI, Tapia VS, Muñoz R, von Marées J, Gaete M, Melo F, Larraín J. Genome-wide expression profile of the response to spinal cord injury in Xenopus laevis reveals extensive differences between regenerative and non-regenerative stages. Neural Dev 2014; 9:12. [PMID: 24885550 PMCID: PMC4046850 DOI: 10.1186/1749-8104-9-12] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/02/2014] [Indexed: 11/23/2022] Open
Abstract
Background Xenopus laevis has regenerative and non-regenerative stages. As a tadpole, it is fully capable of functional recovery after a spinal cord injury, while its juvenile form (froglet) loses this capability during metamorphosis. We envision that comparative studies between regenerative and non-regenerative stages in Xenopus could aid in understanding why spinal cord regeneration fails in human beings. Results To identify the mechanisms that allow the tadpole to regenerate and inhibit regeneration in the froglet, we obtained a transcriptome-wide profile of the response to spinal cord injury in Xenopus regenerative and non-regenerative stages. We found extensive transcriptome changes in regenerative tadpoles at 1 day after injury, while this was only observed by 6 days after injury in non-regenerative froglets. In addition, when comparing both stages, we found that they deployed a very different repertoire of transcripts, with more than 80% of them regulated in only one stage, including previously unannotated transcripts. This was supported by gene ontology enrichment analysis and validated by RT-qPCR, which showed that transcripts involved in metabolism, response to stress, cell cycle, development, immune response and inflammation, neurogenesis, and axonal regeneration were regulated differentially between regenerative and non-regenerative stages. Conclusions We identified differences in the timing of the transcriptional response and in the inventory of regulated transcripts and biological processes activated in response to spinal cord injury when comparing regenerative and non-regenerative stages. These genes and biological processes provide an entry point to understand why regeneration fails in mammals. Furthermore, our results introduce Xenopus laevis as a genetic model organism to study spinal cord regeneration.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Juan Larraín
- Center for Aging and Regeneration, Millennium Nucleus for Regenerative Biology, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.
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Immunohistochemical analysis of Pax6 and Pax7 expression in the CNS of adult Xenopus laevis. J Chem Neuroanat 2014; 57-58:24-41. [DOI: 10.1016/j.jchemneu.2014.03.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 03/26/2014] [Accepted: 03/27/2014] [Indexed: 11/22/2022]
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DeRocher MM, Armaly FH, Lepore CJ, Hollis DM. Rem2 in the bullfrog (Rana catesbeiana): Patterns of expression within the central nervous system and brain expression at different ontogenetic stages. Gene 2014; 540:37-45. [PMID: 24576576 DOI: 10.1016/j.gene.2014.02.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 02/13/2014] [Accepted: 02/18/2014] [Indexed: 12/12/2022]
Abstract
Rem2 is a member of the RGK (Rem, Rad, and Gem/Kir) subfamily of the Ras superfamily of GTP binding proteins. In mammals, Rem2 has been found to be unique in not only its structure, but also its tissue specificity, as it is the first member to be found at high levels in neuronal tissue. Because Rem2 has previously been implicated in neuronal cell proliferation, and amphibians maintain relatively high neuronal proliferative activity as adults, we sought to isolate and acquire the full-length sequence of the rem2 gene from the brain of the bullfrog (Rana catesbeiana). Furthermore, we used real time PCR (rtPCR) to characterize its tissue specificity, regional brain expression, and brain expression levels at different stages of development. Deduced amino acid sequence analysis showed that the bullfrog Rem2 protein possesses the unique 5' extension characteristic of mammalian Rem2 and the RGK subfamily to which it belongs. Tissue specificity of the bullfrog rem2 gene showed that the bullfrog is similar to both mammals and fish in that the levels of rem2 gene expression were significantly greater in the brain than all other tissues assayed. In the brain itself, differential rem2 expression patterns were observed between six major brain areas assayed and the spinal cord, with expression significantly high in the cerebrum and low in the cerebellum. Finally, examination of whole brain rem2 expression levels in bullfrogs at different stages of development revealed greater expression after metamorphic climax.
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Bandín S, Morona R, Moreno N, González A. Regional expression of Pax7 in the brain of Xenopus laevis during embryonic and larval development. Front Neuroanat 2013; 7:48. [PMID: 24399938 PMCID: PMC3871710 DOI: 10.3389/fnana.2013.00048] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/10/2013] [Indexed: 11/13/2022] Open
Abstract
Pax7 is a member of the highly conserved Pax gene family that is expressed in restricted zones of the central nervous system (CNS) during development, being involved in early brain regionalization and the maintenance of the regional identity. Using sensitive immunohistochemical techniques we have analyzed the spatiotemporal pattern of Pax7 expression in the brain of the anuran amphibian Xenopus laevis, during development. Pax7 expression was first detected in early embryos in the basal plate of prosomere 3, roof and alar plates of prosomere 1 and mesencephalon, and the alar plate of rhombomere 1. As development proceeded, Pax7 cells were observed in the hypothalamus close to the catecholaminergic population of the mammillary region. In the diencephalon, Pax7 was intensely expressed in a portion of the basal plate of prosomere 3, in the roof plate and in scattered cells of the thalamus in prosomere 2, throughout the roof of prosomere 1, and in the commissural and juxtacommissural domains of the pretectum. In the mesencephalon, Pax7 cells were localized in the optic tectum and, to a lesser extent, in the torus semicircularis. The rostral portion of the alar part of rhombomere 1, including the ventricular layer of the cerebellum, expressed Pax7 and, gradually, some of these dorsal cells were observed to populate ventrally the interpeduncular nucleus and the isthmus (rhombomere 0). Additionally, Pax7 positive cells were found in the ventricular zone of the ventral part of the alar plate along the rhombencephalon and the spinal cord. The findings show that the strongly conserved features of Pax7 expression through development shared by amniote vertebrates are also present in the anamniote amphibians as a common characteristic of the brain organization of tetrapods.
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Affiliation(s)
- Sandra Bandín
- Department of Cell Biology, Faculty of Biology, University Complutense Madrid, Spain
| | - Ruth Morona
- Department of Cell Biology, Faculty of Biology, University Complutense Madrid, Spain
| | - Nerea Moreno
- Department of Cell Biology, Faculty of Biology, University Complutense Madrid, Spain
| | - Agustín González
- Department of Cell Biology, Faculty of Biology, University Complutense Madrid, Spain
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Anatomical and electrophysiological plasticity of locomotor networks following spinal transection in the salamander. Neurosci Bull 2013; 29:467-76. [PMID: 23893431 DOI: 10.1007/s12264-013-1363-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 05/19/2013] [Indexed: 01/09/2023] Open
Abstract
Recovery of locomotor behavior following spinal cord injury can occur spontaneously in some vertebrates, such as fish, urodele amphibians, and certain reptiles. This review provides an overview of the current status of our knowledge on the anatomical and electrophysiological changes occurring within the spinal cord that lead to, or are associated with the re-expression of locomotion in spinally-transected salamanders. A better understanding of these processes will help to devise strategies for restoring locomotor function in mammals, including humans.
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Lee-Liu D, Edwards-Faret G, Tapia VS, Larraín J. Spinal cord regeneration: Lessons for mammals from non-mammalian vertebrates. Genesis 2013; 51:529-44. [DOI: 10.1002/dvg.22406] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 05/28/2013] [Accepted: 05/29/2013] [Indexed: 02/02/2023]
Affiliation(s)
- Dasfne Lee-Liu
- Center for Aging and Regeneration; Millennium Nucleus in Regenerative Biology; Department of Cell and Molecular Biology; Faculty of Biological Sciences; Pontificia Universidad Católica de Chile; Alameda 340 Santiago Chile
| | - Gabriela Edwards-Faret
- Center for Aging and Regeneration; Millennium Nucleus in Regenerative Biology; Department of Cell and Molecular Biology; Faculty of Biological Sciences; Pontificia Universidad Católica de Chile; Alameda 340 Santiago Chile
| | - Víctor S. Tapia
- Center for Aging and Regeneration; Millennium Nucleus in Regenerative Biology; Department of Cell and Molecular Biology; Faculty of Biological Sciences; Pontificia Universidad Católica de Chile; Alameda 340 Santiago Chile
| | - Juan Larraín
- Center for Aging and Regeneration; Millennium Nucleus in Regenerative Biology; Department of Cell and Molecular Biology; Faculty of Biological Sciences; Pontificia Universidad Católica de Chile; Alameda 340 Santiago Chile
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Spinal cord regeneration: where fish, frogs and salamanders lead the way, can we follow? Biochem J 2013; 451:353-64. [DOI: 10.1042/bj20121807] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Major trauma to the mammalian spinal cord often results in irreversible loss of function, i.e. paralysis, and current therapies ranging from drugs, implantations of stem cells and/or biomaterials, and electrically stimulated nerve regrowth, have so far offered very limited success in improving quality-of-life. However, in marked contrast with this basic shortcoming of ours, certain vertebrate species, including fish and salamanders, display the amazing ability to faithfully regenerate various complex body structures after injury or ablation, restoring full functionality, even in the case of the spinal cord. Despite the inherently strong and obvious translational potential for improving treatment strategies for human patients, our in-depth molecular-level understanding of these decidedly more advanced repair systems remains in its infancy. In the present review, we will discuss the current state of this field, focusing on recent progress in such molecular analyses using various regenerative species, and how these so far relate to the mammalian situation.
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Avci HX, Flamant F, Dusart I. [Thyroid hormone T3 triggers the developmental loss of axonal regenerative capacity]. Med Sci (Paris) 2013; 29:245-7. [PMID: 23544373 DOI: 10.1051/medsci/2013293005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Thyroid hormone triggers the developmental loss of axonal regenerative capacity via thyroid hormone receptor α1 and krüppel-like factor 9 in Purkinje cells. Proc Natl Acad Sci U S A 2012; 109:14206-11. [PMID: 22891348 DOI: 10.1073/pnas.1119853109] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neurons in the CNS of higher vertebrates lose their ability to regenerate their axons at a stage of development that coincides with peak circulating thyroid hormone (T(3)) levels. Here, we examined whether this peak in T(3) is involved in the loss of axonal regenerative capacity in Purkinje cells (PCs). This event occurs at the end of the first postnatal week in mice. Using organotypic culture, we found that the loss of axon regenerative capacity was triggered prematurely by early exposure of mouse PCs to T(3), whereas it was delayed in the absence of T(3). Analysis of mutant mice showed that this effect was mainly mediated by the T(3) receptor α1. Using gain- and loss-of-function approaches, we also showed that Krüppel-like factor 9 was a key mediator of this effect of T(3). These results indicate that the sudden physiological increase in T(3) during development is involved in the onset of the loss of axon regenerative capacity in PCs. This loss of regenerative capacity might be part of the general program triggered by T(3) throughout the body, which adapts the animal to its postnatal environment.
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Gaete M, Muñoz R, Sánchez N, Tampe R, Moreno M, Contreras EG, Lee-Liu D, Larraín J. Spinal cord regeneration in Xenopus tadpoles proceeds through activation of Sox2-positive cells. Neural Dev 2012; 7:13. [PMID: 22537391 PMCID: PMC3425087 DOI: 10.1186/1749-8104-7-13] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 04/26/2012] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND In contrast to mammals, amphibians, such as adult urodeles (for example, newts) and anuran larvae (for example, Xenopus) can regenerate their spinal cord after injury. However, the cellular and molecular mechanisms involved in this process are still poorly understood. RESULTS Here, we report that tail amputation results in a global increase of Sox2 levels and proliferation of Sox2(+) cells. Overexpression of a dominant negative form of Sox2 diminished proliferation of spinal cord resident cells affecting tail regeneration after amputation, suggesting that spinal cord regeneration is crucial for the whole process. After spinal cord transection, Sox2(+) cells are found in the ablation gap forming aggregates. Furthermore, Sox2 levels correlated with regenerative capabilities during metamorphosis, observing a decrease in Sox2 levels at non-regenerative stages. CONCLUSIONS Sox2(+) cells contribute to the regeneration of spinal cord after tail amputation and transection. Sox2 levels decreases during metamorphosis concomitantly with the lost of regenerative capabilities. Our results lead to a working hypothesis in which spinal cord damage activates proliferation and/or migration of Sox2(+) cells, thus allowing regeneration of the spinal cord after tail amputation or reconstitution of the ependymal epithelium after spinal cord transection.
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Affiliation(s)
- Marcia Gaete
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
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Smith J, Morgan JR, Zottoli SJ, Smith PJ, Buxbaum JD, Bloom OE. Regeneration in the era of functional genomics and gene network analysis. THE BIOLOGICAL BULLETIN 2011; 221:18-34. [PMID: 21876108 PMCID: PMC4109899 DOI: 10.1086/bblv221n1p18] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
What gives an organism the ability to regrow tissues and to recover function where another organism fails is the central problem of regenerative biology. The challenge is to describe the mechanisms of regeneration at the molecular level, delivering detailed insights into the many components that are cross-regulated. In other words, a broad, yet deep dissection of the system-wide network of molecular interactions is needed. Functional genomics has been used to elucidate gene regulatory networks (GRNs) in developing tissues, which, like regeneration, are complex systems. Therefore, we reason that the GRN approach, aided by next generation technologies, can also be applied to study the molecular mechanisms underlying the complex functions of regeneration. We ask what characteristics a model system must have to support a GRN analysis. Our discussion focuses on regeneration in the central nervous system, where loss of function has particularly devastating consequences for an organism. We examine a cohort of cells conserved across all vertebrates, the reticulospinal (RS) neurons, which lend themselves well to experimental manipulations. In the lamprey, a jawless vertebrate, there are giant RS neurons whose large size and ability to regenerate make them particularly suited for a GRN analysis. Adding to their value, a distinct subset of lamprey RS neurons reproducibly fail to regenerate, presenting an opportunity for side-by-side comparison of gene networks that promote or inhibit regeneration. Thus, determining the GRN for regeneration in RS neurons will provide a mechanistic understanding of the fundamental cues that lead to success or failure to regenerate.
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Affiliation(s)
- Joel Smith
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering and The Josephine Bay Pau Center for Comparative Molecular Biology and Evolution, The Marine Biological Laboratory, 7 MBL Street, Woods Hole, Massachusetts 02543
- Co-corresponding authors: and obloom@ nshs.edu
| | - Jennifer R. Morgan
- Section of Molecular Cell and Developmental Biology, Institute for Cell and Molecular Biology, Institute for Neuroscience, University of Texas at Austin, Austin, Texas 78712
| | - Steven J. Zottoli
- Department of Biology, 59 Lab Campus Drive, Williams College, Williamstown, Massachusetts 01267 and Cellular Dynamics Program, The Marine Biological Laboratory, 7 MBL Street, Woods Hole, Massachusetts 02453
| | - Peter J. Smith
- The Biocurrents Research Center, Cellular Dynamics Program, The Marine Biological Laboratory, 7 MBL Street, Woods Hole, Massachusetts 02543
| | - Joseph D. Buxbaum
- Department of Psychiatry and the Friedman Brain Institute, Mount Sinai School of Medicine, One Gustave L Levy Plc, Box 1668, New York, New York 10029
| | - Ona E. Bloom
- The Center for Autoimmune and Musculoskeletal Disease, The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, New York 11030
- Co-corresponding authors: and obloom@ nshs.edu
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Rehermann MI, Santiñaque FF, López-Carro B, Russo RE, Trujillo-Cenóz O. Cell proliferation and cytoarchitectural remodeling during spinal cord reconnection in the fresh-water turtle Trachemys dorbignyi. Cell Tissue Res 2011; 344:415-33. [PMID: 21574060 DOI: 10.1007/s00441-011-1173-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 04/11/2011] [Indexed: 01/22/2023]
Abstract
In fresh-water turtles, the bridge connecting the proximal and caudal stumps of transected spinal cords consists of regenerating axons running through a glial cellular matrix. To understand the process leading to the generation of the scaffold bridging the lesion, we analyzed the mitotic activity triggered by spinal injury in animals maintained alive for 20-30 days after spinal cord transection. Flow cytometry and bromodeoxyuridine (BrdU)-labeling experiments revealed a significant increment of cycling cells around the lesion epicenter. BrdU-tagged cells maintained a close association with regenerating axons. Most dividing cells expressed the brain lipid-binding protein (BLBP). Cells with BrdU-positive nuclei expressed glial fibrillary acidic protein. As spinal cord regeneration involves dynamic cell rearrangements, we explored the ultra-structure of the bridge and found cells with the aspect of immature oligodendrocytes forming an embryonic-like microenvironment. These cells supported and ensheathed regenerating axons that were recognized by immunocytological and electron-microscopical procedures. Since functional recovery depends on proper impulse transmission, we examined the anatomical axon-glia relationships near the lesion epicenter. Computer-assisted three-dimensional models revealed helical axon-glial junctions in which the intercellular space appeared to be reduced (5-7 nm). Serial-sectioning analysis revealed that fibril-containing processes provided myelinating axon sheaths. Thus, disruption of the ependymal layer elicits mitotic activity predominantly in radial glia expressing BLBP on the lateral aspects of the ependyma. These cycling cells seem to migrate and contribute to the bridge providing the main support and sheaths for regenerating axons.
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Affiliation(s)
- María Inés Rehermann
- Departamento de Neurofisiología Celular y Molecular, Avenida Italia 3318, Montevideo, Uruguay
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Gibbs KM, Chittur SV, Szaro BG. Metamorphosis and the regenerative capacity of spinal cord axons in Xenopus laevis. Eur J Neurosci 2010; 33:9-25. [PMID: 21059114 DOI: 10.1111/j.1460-9568.2010.07477.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Throughout the vertebrate subphylum, the regenerative potential of central nervous system axons is greatest in embryonic stages and declines as development progresses. For example, Xenopus laevis can functionally recover from complete transection of the spinal cord as a tadpole but is unable to do so after metamorphosing into a frog. Neurons of the reticular formation and raphe nucleus are among those that regenerate axons most reliably in tadpole and that lose this ability after metamorphosis. To identify molecular factors associated with the success and failure of spinal cord axon regeneration, we pharmacologically manipulated thyroid hormone (TH) levels using methimazole or triiodothyronine, to either keep tadpoles in a permanently larval state or induce precocious metamorphosis, respectively. Following complete spinal cord transection, serotonergic axons crossed the lesion site and tadpole swimming ability was restored when metamorphosis was inhibited, but these events failed to occur when metamorphosis was prematurely induced. Thus, the metamorphic events controlled by TH led directly to the loss of regenerative potential. Microarray analysis identified changes in hindbrain gene expression that accompanied regeneration-permissive and -inhibitory conditions, including many genes in the permissive condition that have been previously associated with axon outgrowth and neuroprotection. These data demonstrate that changes in gene expression occur within regenerating neurons in response to axotomy under regeneration-permissive conditions in which normal development has been suspended, and they identify candidate genes for future studies of how central nervous system axons can successfully regenerate in some vertebrates.
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Affiliation(s)
- Kurt M Gibbs
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA
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Abstract
For many years the mammalian CNS has been seen as an organ that is unable to regenerate. However, it was also long known that lower vertebrate species are capable of impressive regeneration of CNS structures. How did this situation arise through evolution? Increasing cellular and molecular understanding of regeneration in different animal species coupled with studies of adult neurogenesis in mammals is providing a basis for addressing this question. Here we compare CNS regeneration among vertebrates and speculate on how this ability may have emerged or been restricted.
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Moreno-Manzano V, Rodríguez-Jiménez FJ, García-Roselló M, Laínez S, Erceg S, Calvo MT, Ronaghi M, Lloret M, Planells-Cases R, Sánchez-Puelles JM, Stojkovic M. Activated spinal cord ependymal stem cells rescue neurological function. Stem Cells 2009; 27:733-43. [PMID: 19259940 DOI: 10.1002/stem.24] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Spinal cord injury (SCI) is a major cause of paralysis. Currently, there are no effective therapies to reverse this disabling condition. The presence of ependymal stem/progenitor cells (epSPCs) in the adult spinal cord suggests that endogenous stem cell-associated mechanisms might be exploited to repair spinal cord lesions. epSPC cells that proliferate after SCI are recruited by the injured zone, and can be modulated by innate and adaptive immune responses. Here we demonstrate that when epSPCs are cultured from rats with a SCI (ependymal stem/progenitor cells injury [epSPCi]), these cells proliferate 10 times faster in vitro than epSPC derived from control animals and display enhanced self renewal. Genetic profile analysis revealed an important influence of inflammation on signaling pathways in epSPCi after injury, including the upregulation of Jak/Stat and mitogen activated protein kinase pathways. Although neurospheres derived from either epSPCs or epSPCi differentiated efficiently to oligodendrocites and functional spinal motoneurons, a better yield of differentiated cells was consistently obtained from epSPCi cultures. Acute transplantation of undifferentiated epSPCi or the resulting oligodendrocyte precursor cells into a rat model of severe spinal cord contusion produced a significant recovery of motor activity 1 week after injury. These transplanted cells migrated long distances from the rostral and caudal regions of the transplant to the neurofilament-labeled axons in and around the lesion zone. Our findings demonstrate that modulation of endogenous epSPCs represents a viable cell-based strategy for restoring neuronal dysfunction in patients with spinal cord damage.
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Robust axonal growth and a blunted macrophage response are associated with impaired functional recovery after spinal cord injury in the MRL/MpJ mouse. Neuroscience 2008; 156:498-514. [PMID: 18786615 DOI: 10.1016/j.neuroscience.2008.08.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Revised: 08/04/2008] [Accepted: 08/05/2008] [Indexed: 01/19/2023]
Abstract
Spinal cord injury (SCI) in mammals leads to a robust inflammatory response followed by the formation of a glial and connective tissue scar that comprises a barrier to axonal regeneration. The inbred MRL/MpJ mouse strain exhibits reduced inflammation after peripheral injury and shows true regeneration without tissue scar formation following an ear punch wound. We hypothesized that following SCI, the unique genetic wound healing traits of this strain would result in reduced glial and connective tissue scar formation, increased axonal growth, and improved functional recovery. Adult MRL/MpJ and C57BL/6J mice were subjected to a mid-thoracic spinal contusion and the distribution of axon profiles and selected cellular and extracellular matrix components was compared at 1, 2, 4 and 6 weeks post-injury. Recovery of hind-limb locomotor function was assessed over the same time period. The MRL/MpJ mice exhibited robust axon growth within the lesion, beginning at 4 weeks post-injury. This growth was accompanied by reduced macrophage staining at 1, 2, 4 and 6 weeks post-injury, decreased chondroitin sulfate proteoglycan staining at 1-2 weeks and increased laminin staining throughout the lesion at 2-6 weeks post-injury. Paradoxically, the extent of locomotor recovery was impaired in the MRL/MpJ mice. Close examination of the chronic lesion site revealed evidence of ongoing degeneration both within and surrounding the lesion site. Thus, the regenerative genetic wound healing traits of the MRL/MpJ mice contribute to the evolution of a lesion environment that supports enhanced axon growth after SCI. However, this response occurs at the expense of meaningful functional recovery.
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da Costa ES, Carvalho AL, Martinez AMB, De-Ary-Pires B, Pires-Neto MA, de Ary-Pires R. Strapping the spinal cord: an innovative experimental model of CNS injury in rats. J Neurosci Methods 2008; 170:130-9. [PMID: 18291533 DOI: 10.1016/j.jneumeth.2008.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Revised: 12/23/2007] [Accepted: 01/04/2008] [Indexed: 11/18/2022]
Abstract
Experimental models of spinal cord (SC) lesion are essential for understanding a few of the primary and secondary mechanisms of injury and functional recovery of the central nervous system (CNS). We have developed an experimental model of SC injury in adult rats (n=32), that involves the use of a device (SC-STRAPPER) that straps the SC and promotes gradual and controlled SC injury similar to clinical compressive SC injuries. SC strapping is a less-invasive procedure in comparison to other SC injury models, and it performs compression with smaller infection risk and undetectable paravertebral or vertebral lesions. The survival of the rats was 100%, minimizing the suffering of the animals. We have analyzed the histopathological changes that occur during experimental SC compression, as well as the immunohistochemical labeling for glial fibrillary acidic protein (GFAP). Animals survived for 21 days being thereafter anesthetized and perfused with aldehydes. SC lesions were associated with motor deficits and local increase in GFAP immunolabeling proportionate to the severity of the compression. This experimental model represents a potential contribution for neuroscientific research, providing a low-cost and rather simple system of controllable and reproducible SC experimental damage.
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Affiliation(s)
- Elizabete Sant'Anna da Costa
- Departamento de Anatomia, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Brazil
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Nyatia E, Lang DM. Localisation and expression of a myelin associated neurite inhibitor, Nogo-A and its receptor Nogo-receptor by mammalian CNS cells. Res Vet Sci 2007; 83:287-301. [PMID: 17428512 DOI: 10.1016/j.rvsc.2007.01.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Revised: 11/17/2006] [Accepted: 01/21/2007] [Indexed: 10/23/2022]
Abstract
Axon regeneration failure in the adult mammalian central nervous system (CNS) is partly due to inhibitory molecules associated with myelin. The Nogo receptor (NgR) plays a role in this process through an extraordinary degree of cross reactivity with three structurally unrelated myelin-associated inhibitory ligands namely; Nogo-A, myelin associated glycoprotein (MAG) and oligodendrocyte myelin glycoprotein (OMgp). The major aim of the study was to investigate and explore the cellular localisation and expression pattern of NgR and Nogo-A in the mammalian nervous system. We therefore generated a rabbit polyclonal anti-NgR antibody from the leucine rich repeat (LRR) No. 9 domain of the NgR polypeptide chain. Together with a commercially available polyclonal antibody specific for NgR, and in conjunction with double labeling immunofluorescence methods on cryosections and cell cultures, NgR immunoreactivity was observed in the CNS and dorsal root ganglia (DRG). In cellular populations, it was confined to neuronal cell bodies and their processes. NgR was also localised on the surface of extending DRG intact axons and growth cones in live staining experiments. Nogo-A, a member of the reticulon family protein, was widely distributed in the mammalian brain, spinal cord, and DRG. Intense Nogo-A immunoreactivity was also detected in oligodendrocyte cell bodies and their myelin sheaths in nerve fibre tracts of the CNS. Furthermore, numerous populations of neurons in the brain and spinal cord expressed Nogo-A to a variable extent in their cell bodies and neurites, suggesting additional, as-yet-unknown, functions of this protein. These results confirm results obtained by other researchers with different sets of antibodies. However, they also raise the question of the mechanism and circumstances under which NgR interacts with Nogo-A, as the latter appears to be confined to the cytoplasm and can therefore not be expected to bind NgR on the axon surface.
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Affiliation(s)
- E Nyatia
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa.
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Gibbs KM, Szaro BG. Regeneration of descending projections in Xenopus laevis tadpole spinal cord demonstrated by retrograde double labeling. Brain Res 2006; 1088:68-72. [PMID: 16626660 DOI: 10.1016/j.brainres.2006.02.126] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Revised: 02/24/2006] [Accepted: 02/24/2006] [Indexed: 11/28/2022]
Abstract
Xenopus laevis tadpoles functionally recover from spinal cord transection. Because this recovery requires the tadpole to metamorphose, it may result from compensatory changes initiated by de novo growth of axons involved in limb dominant locomotion rather than from regeneration of cut axons. To determine whether axonal regrowth contributes to functional recovery, sequential retrograde double labeling with two fluorescent dextran amines was used to identify neurons with regenerated axons. Rhodamine dextran amine was applied to hemisected spinal cords of prometamorphic tadpoles between the 4th and 5th vertebrae. After metamorphosis, in animals that had recovered movement, fluorescein dextran amine was applied to the lumbar spinal cord. Two weeks later, the CNS of these animals was examined for the presence of double-labeled neurons, i.e., those whose axons had regenerated. Double-labeled neurons were found in the reticular, raphe, and solitary tract nuclei, and in the interstitial nucleus of the medial longitudinal fasciculus. Because Xenopus expresses all the known mammalian molecular inhibitors of CNS axon regeneration, the determination that these phylogenetically conserved populations of neurons are indeed capable of axon regeneration should facilitate molecular studies of successful recovery from spinal cord trauma.
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Affiliation(s)
- Kurt M Gibbs
- Department of Biological Sciences, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY 12222, USA
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Mothe AJ, Tator CH. Proliferation, migration, and differentiation of endogenous ependymal region stem/progenitor cells following minimal spinal cord injury in the adult rat. Neuroscience 2005; 131:177-87. [PMID: 15680701 DOI: 10.1016/j.neuroscience.2004.10.011] [Citation(s) in RCA: 233] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2004] [Indexed: 11/20/2022]
Abstract
Ependymal cells of the adult mammalian spinal cord exhibit stem/progenitor cell properties following injury. In the present study, we utilized intraventricular injection of 1,1'-dioctadecyl-6,6'-di(4-sulfophenyl)-3,3,3',3'-tetramethylindocarbocyanine (DiI) to label the ependyma lining the central canal to allow tracking of the migration of endogenous ependymal cells and their progeny after spinal cord injury (SCI). We developed a minimal injury model that preserved the integrity of the central canal and did not interfere with ependymal cell labeling. Three days following SCI, there was an 8.6-fold increase in the proliferative labeling index of the ependymal cells at the level of the needle track based on bromodeoxyuridine labeling, compared with 1 day post-injury. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) positive cells were not detected in the ependyma or surrounding gray matter, indicating that ependymal cells do not undergo apoptosis in response to minimal injury. Nestin was rapidly induced in the ependyma by 1 day and expression peaked by 7 days post-injury. We quantitated the number and distance of ependymal cell migration following minimal injury. The number of ependymal cells migrating from the region of the central canal increased by 3 days following minimal injury and DiI-labeled glial fibrillary acidic protein expressing cells were detected 14 days post-SCI, most of which migrated within 70 microm of the region of the central canal. These results show that a minimal SCI adjacent to the ependyma is sufficient to induce an endogenous ependymal cell response where ependymal stem/progenitor cells proliferate and migrate from the region of the central canal, differentiating primarily into astrocytes.
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Affiliation(s)
- A J Mothe
- Toronto Western Research Institute and Krembil Neuroscience Centre, McL 12-423, 399 Bathurst Street, Toronto, Ontario, Canada M5T 2S8
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Vergara MN, Arsenijevic Y, Del Rio-Tsonis K. CNS regeneration: A morphogen's tale. ACTA ACUST UNITED AC 2005; 64:491-507. [PMID: 16041757 DOI: 10.1002/neu.20158] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Tissue regeneration will soon become an avenue for repair of damaged or diseased tissues as stem cell niches have been found in almost every organ of the vertebrate body including the CNS. In addition, different animals display an array of regenerative capabilities that are currently being researched to dissect the molecular mechanisms involved. This review concentrates on the different ways in which CNS tissues such as brain, spinal cord and retina can regenerate or display neurogenic potential and how these abilities are modulated by morphogens.
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Klinger M, Diekmann H, Heinz D, Hirsch C, Hannbeck von Hanwehr S, Petrausch B, Oertle T, Schwab ME, Stuermer CAO. Identification of two nogo/rtn4 genes and analysis of Nogo-A expression in Xenopus laevis. Mol Cell Neurosci 2004; 25:205-16. [PMID: 15019938 DOI: 10.1016/j.mcn.2003.09.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2003] [Revised: 09/15/2003] [Accepted: 09/29/2003] [Indexed: 11/17/2022] Open
Abstract
Myelin-associated axon growth inhibitors such as Nogo-A/RTN4-A impair axon regeneration in the adult mammalian central nervous system (CNS). Here, we describe the cloning and expression of two independent Xenopus laevis rtn4 orthologs. As in mammals, alternative transcripts are generated both through differential splicing and promoter usage, giving rise to Xenopus nogo-A, -B, -C and to a new isoform, nogo-N/rtn4-N. Xenopus is therefore the 'lowest' vertebrate where Nogo-A was identified. Xenopus Nogo-A/RTN4-A is predominantly expressed in the nervous system, whereas the other isoforms mainly occur in nonneuronal tissues. Nogo-A/RTN4-A specific antisera detect the protein in myelinated fiber tracts of the spinal cord, hindbrain, optic nerve, tectum opticum and in isolated oligodendrocytes. In addition, subpopulations of CNS neurons are Nogo-A/RTN4-A positive. This expression pattern is consistent with that observed for rat Nogo-A and suggests similar functions. Nogo-A in Xenopus myelin might therefore contribute to the failure of spinal cord regeneration in frogs-a feature that may have evolved during the transition from fish to land vertebrates.
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Affiliation(s)
- Michael Klinger
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
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Oertle T, Klinger M, Stuermer CAO, Schwab ME. A reticular rhapsody: phylogenic evolution and nomenclature of the RTN/Nogo gene family. FASEB J 2003; 17:1238-47. [PMID: 12832288 DOI: 10.1096/fj.02-1166hyp] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Reticulon (RTN) genes code for a family of proteins relatively recently described in higher vertebrates. The four known mammalian paralogues (RTN1, -2, -3, and -4/Nogo) have homologous carboxyl termini with two characteristic large hydrophobic regions. Except for RTN4-A/Nogo-A, thought to be an inhibitor for neurite outgrowth, restricting the regenerative capabilities of the mammalian CNS after injury, the functions of other family members are largely unknown. The overall occurrence of RTNs in different phyla and the evolution of the RTN gene family have hitherto not been analyzed. Here we expound data showing that the RTN family has arisen during early eukaryotic evolution potentially concerted to the establishment of the endomembrane system. Over 250 reticulon-like (RTNL) genes were identified in deeply diverging eukaryotes, fungi, plants, and animals. A systematic nomenclature for all identified family members is introduced. The analysis of exon-intron arrangements and of protein homologies allowed us to isolate key steps in the history of these genes. Our data corroborate the hypothesis that present RTNs evolved from an intron-rich reticulon ancestor mainly by the loss of different introns in diverse phyla. We also present evidence that the exceptionally large RTN4-A-specific exon 3, which harbors a potent neurite growth inhibitory region, may have arisen de novo approximately 350 MYA during transition to land vertebrates. These data emphasize on the one hand the universal role of reticulons in the eukaryotic system and on the other hand the acquisition of putative new functions through acquirement of novel amino-terminal exons.
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Affiliation(s)
- Thomas Oertle
- Brain Research Institute, University of Zurich, and Department of Biology, ETH Zurich, 8057 Zurich, Switzerland.
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Armstrong J, Zhang L, McClellan AD. Axonal regeneration of descending and ascending spinal projection neurons in spinal cord-transected larval lamprey. Exp Neurol 2003; 180:156-66. [PMID: 12684029 DOI: 10.1016/s0014-4886(02)00057-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The distributions of descending and ascending spinal projection neurons (i.e., spinal neurons with moderate to long axons) were compared in normal larval lamprey and in animals that had recovered for 8 weeks following a complete spinal cord transection at 50% body length (BL, normalized distance from the anterior head). In normal animals, application of HRP to the spinal cord at 60% BL (40% BL) labeled an average of 713.8 +/- 143.2 descending spinal projection neurons (718.4 +/- 108.0 ascending spinal projection neurons) along the rostral (caudal) spinal cord, most of which were unidentified neurons. Some of these neurons project for at least approximately 50-60 spinal cord segments (approximately 36-47 mm in animals with an average length of approximately 90 mm used in the present study). At 8 weeks posttransection, the numbers of HRP-labeled descending or ascending spinal neurons that extended their axons through the transection were about 40% of those in similar areas of the spinal cord in normal animals. Thus, in larval lamprey, axonal regeneration of descending and ascending spinal projection neurons is incomplete, similar to that found for descending brain neurons. The majority of restored projections were from unidentified spinal neurons that have not been documented previously. In contrast to results from several other lower vertebrates, in the lamprey ascending spinal neurons exhibited substantial axonal regeneration. Identified descending spinal neurons, such as lateral interneurons and crossed contralateral interneurons, and identified ascending spinal neurons, such as giant interneurons and edge cells, regenerated their axons at least 9 mm beyond the transection site in animals with an average length of approximately 90 mm, which is appreciably farther than previously reported. In contrast, most dorsal cells, which are centrally located sensory neurons, exhibited very little axonal regeneration.
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Affiliation(s)
- Jon Armstrong
- Division of Biological Sciences and Interdisciplinary Neuroscience Program, University of Missouri, Columbia, MO 65211-6190, USA
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Chernoff EAG, Sato K, Corn A, Karcavich RE. Spinal cord regeneration: intrinsic properties and emerging mechanisms. Semin Cell Dev Biol 2002; 13:361-8. [PMID: 12324218 DOI: 10.1016/s1084952102000927] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Injured spinal cord regenerates in adult fish and urodele amphibians, young tadpoles of anuran amphibians, lizard tails, embryonic birds and mammals, and in adults of at least some strains of mice. The extent of this regeneration is described with respect to axonal regrowth, neurogenesis, glial responses, and maintenance of an 'embryonic' environment. The regeneration process in amphibian spinal cord demonstrates that gap replacement and caudal regeneration share some properties with developing spinal cord. This review considers the extent to which intrinsically regenerating spinal cord demonstrates neural stem cell behavior and to what extent anterior-posterior and dorsal-ventral patterning might be involved.
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Affiliation(s)
- Ellen A G Chernoff
- Department of Biology and the Indiana University Center for Regenerative Biology and Medicine, School of Science, Indiana University-Purdue University Indianapolis (IUPUI), 723 W. Michigan St., Indianapolis, IN 46202-5132, USA.
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Giménez y Ribotta M, Menet V, Privat A. The role of astrocytes in axonal regeneration in the mammalian CNS. PROGRESS IN BRAIN RESEARCH 2001; 132:587-610. [PMID: 11545022 DOI: 10.1016/s0079-6123(01)32105-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Affiliation(s)
- M Giménez y Ribotta
- INSERM U336, Université Montpellier II, Place E. Bataillon, B.P. 106, 34095 Montpellier, France
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Beattie MS, Li Q, Bresnahan JC. Cell death and plasticity after experimental spinal cord injury. PROGRESS IN BRAIN RESEARCH 2001; 128:9-21. [PMID: 11105665 DOI: 10.1016/s0079-6123(00)28003-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- M S Beattie
- Department of Neuroscience, Ohio State University, Columbus 43210, USA.
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Martin GF, Terman JR, Wang XM. Regeneration of descending spinal axons after transection of the thoracic spinal cord during early development in the North American opossum, Didelphis virginiana. Brain Res Bull 2000; 53:677-87. [PMID: 11165803 DOI: 10.1016/s0361-9230(00)00401-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Opossums are born in an immature, fetal-like state, making it possible to lesion their spinal cord early in development without intrauterine surgery. When the thoracic spinal cord of the North American opossum, Didelphis virginiana, is transected on postnatal day 5, and injections of Fast Blue (FB) are made caudal to the lesion site 30-40 days or 6 months later, neurons are labeled in all of the spinal and supraspinal areas that are labeled after comparable injections in age-matched, unlesioned controls. Double-labeling studies document that regeneration of cut axons contributes to growth of axons through the lesion site and behavioral studies show that animals lesioned on postnatal day 5 use their hindlimbs in normal appearing locomotion as adults. The critical period for developmental plasticity of descending spinal axons extends to postnatal day 26, although axons which grow through the lesion site become fewer in number and more restricted as to origin with increasing age. Animals lesioned between postnatal day 12 and 26 use the hindlimbs better than animals lesioned as adults, but hindlimb function is markedly abnormal and uncoordinated with that of the forelimbs. We conclude that restoration of anatomical continuity occurs after transection of the spinal cord in developing opossums, that descending axons grow through the lesion site, that regeneration of cut axons contributes to such growth, and that animals lesioned early enough in development have relatively normal motor function as adults.
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Affiliation(s)
- G F Martin
- Department of Anatomy and Medical Education, The Ohio State University, College of Medicine and Public Health, Columbus, OH 43210, USA
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