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The Role of Tissue Geometry in Spinal Cord Regeneration. MEDICINA (KAUNAS, LITHUANIA) 2022; 58:medicina58040542. [PMID: 35454380 PMCID: PMC9028021 DOI: 10.3390/medicina58040542] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/11/2022] [Indexed: 11/17/2022]
Abstract
Unlike peripheral nerves, axonal regeneration is limited following injury to the spinal cord. While there may be reduced regenerative potential of injured neurons, the central nervous system (CNS) white matter environment appears to be more significant in limiting regrowth. Several factors may inhibit regeneration, and their neutralization can modestly enhance regrowth. However, most investigations have not considered the cytoarchitecture of spinal cord white matter. Several lines of investigation demonstrate that axonal regeneration is enhanced by maintaining, repairing, or reconstituting the parallel geometry of the spinal cord white matter. In this review, we focus on environmental factors that have been implicated as putative inhibitors of axonal regeneration and the evidence that their organization may be an important determinant in whether they inhibit or promote regeneration. Consideration of tissue geometry may be important for developing successful strategies to promote spinal cord regeneration.
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2
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Cao Z, Man W, Xiong Y, Guo Y, Yang S, Liu D, Zhao H, Yang Y, Yao S, Li C, Zhao L, Sun X, Guo H, Wang G, Wang X. White matter regeneration induced by aligned fibrin nanofiber hydrogel contributes to motor functional recovery in canine T12 spinal cord injury. Regen Biomater 2021; 9:rbab069. [PMID: 35558095 PMCID: PMC9089163 DOI: 10.1093/rb/rbab069] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 09/24/2021] [Accepted: 11/16/2021] [Indexed: 11/25/2022] Open
Abstract
A hierarchically aligned fibrin hydrogel (AFG) that possesses soft stiffness and aligned nanofiber structure has been successfully proven to facilitate neuroregeneration in vitro and in vivo. However, its potential in promoting nerve regeneration in large animal models that is critical for clinical translation has not been sufficiently specified. Here, the effects of AFG on directing neuroregeneration in canine hemisected T12 spinal cord injuries were explored. Histologically obvious white matter regeneration consisting of a large area of consecutive, compact and aligned nerve fibers is induced by AFG, leading to a significant motor functional restoration. The canines with AFG implantation start to stand well with their defective legs from 3 to 4 weeks postoperatively and even effortlessly climb the steps from 7 to 8 weeks. Moreover, high-resolution multi-shot diffusion tensor imaging illustrates the spatiotemporal dynamics of nerve regeneration rapidly crossing the lesion within 4 weeks in the AFG group. Our findings indicate that AFG could be a potential therapeutic vehicle for spinal cord injury by inducing rapid white matter regeneration and restoring locomotion, pointing out its promising prospect in clinic practice.
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Affiliation(s)
- Zheng Cao
- State Key Laboratory of New Ceramics and Fine Processing, Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Weitao Man
- State Key Laboratory of New Ceramics and Fine Processing, Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
- Department of Neurosurgery, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing 102218, China
| | - Yuhui Xiong
- Center for Biomedical Imaging Research, Tsinghua University, Beijing 100084, China
| | - Yi Guo
- Department of Neurosurgery, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing 102218, China
| | - Shuhui Yang
- State Key Laboratory of New Ceramics and Fine Processing, Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Dongkang Liu
- Department of Neurosurgery, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing 102218, China
| | - He Zhao
- State Key Laboratory of New Ceramics and Fine Processing, Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
- Department of Orthopedics, Dongzhimen Hospital, Beijing 100007, China
| | - Yongdong Yang
- Department of Orthopedics, Dongzhimen Hospital, Beijing 100007, China
| | - Shenglian Yao
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Chuzhong Li
- Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Beijing 100070, China
| | - Lingyun Zhao
- State Key Laboratory of New Ceramics and Fine Processing, Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Xiaodan Sun
- State Key Laboratory of New Ceramics and Fine Processing, Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Hua Guo
- Center for Biomedical Imaging Research, Tsinghua University, Beijing 100084, China
| | - Guihuai Wang
- Department of Neurosurgery, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing 102218, China
| | - Xiumei Wang
- State Key Laboratory of New Ceramics and Fine Processing, Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
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3
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Wu D, Jin Y, Shapiro TM, Hinduja A, Baas PW, Tom VJ. Chronic neuronal activation increases dynamic microtubules to enhance functional axon regeneration after dorsal root crush injury. Nat Commun 2020; 11:6131. [PMID: 33257677 PMCID: PMC7705672 DOI: 10.1038/s41467-020-19914-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 11/05/2020] [Indexed: 12/26/2022] Open
Abstract
After a dorsal root crush injury, centrally-projecting sensory axons fail to regenerate across the dorsal root entry zone (DREZ) to extend into the spinal cord. We find that chemogenetic activation of adult dorsal root ganglion (DRG) neurons improves axon growth on an in vitro model of the inhibitory environment after injury. Moreover, repeated bouts of daily chemogenetic activation of adult DRG neurons for 12 weeks post-crush in vivo enhances axon regeneration across a chondroitinase-digested DREZ into spinal gray matter, where the regenerating axons form functional synapses and mediate behavioral recovery in a sensorimotor task. Neuronal activation-mediated axon extension is dependent upon changes in the status of tubulin post-translational modifications indicative of highly dynamic microtubules (as opposed to stable microtubules) within the distal axon, illuminating a novel mechanism underlying stimulation-mediated axon growth. We have identified an effective combinatory strategy to promote functionally-relevant axon regeneration of adult neurons into the CNS after injury.
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Affiliation(s)
- Di Wu
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Ying Jin
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Tatiana M Shapiro
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Abhishek Hinduja
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Veronica J Tom
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA.
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4
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Segregated neural explants exhibit co-oriented, asymmetric, neurite outgrowth. PLoS One 2019; 14:e0216263. [PMID: 31487284 PMCID: PMC6728047 DOI: 10.1371/journal.pone.0216263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 08/19/2019] [Indexed: 11/28/2022] Open
Abstract
Explants of embryonic chick sympathetic and sensory ganglia were found to exhibit asymmetric radial outgrowth of neurites under standard culture conditions with or without exogenous Nerve Growth Factor [NGF]. Opposing sides of an explant exhibited: a) differences in neurite length and, b) differences in neurite morphology. Strikingly, this asymmetry exhibited co-orientation among segregated, neighboring explants. The underlying mechanism(s) of the asymmetry and its co-orientation are not known but appear to depend on cell clustering because dissociated sympathetic neurons do not exhibit co-orientation whereas re-aggregated clusters of cells do. This emergent behavior may be similar to the community effect described in other cell types. If a similar phenomenon exists in the embryo, or in maturity, it may contribute to the establishment of proper orientation of neurite outgrowth during development and/or injury-induced neuronal plasticity.
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5
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Altinova H, Möllers S, Führmann T, Deumens R, Bozkurt A, Heschel I, Damink LHHO, Schügner F, Weis J, Brook GA. Functional improvement following implantation of a microstructured, type-I collagen scaffold into experimental injuries of the adult rat spinal cord. Brain Res 2014; 1585:37-50. [PMID: 25193604 DOI: 10.1016/j.brainres.2014.08.041] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Revised: 08/10/2014] [Accepted: 08/14/2014] [Indexed: 12/14/2022]
Abstract
The formation of cystic cavitation following severe spinal cord injury (SCI) constitutes one of the major barriers to successful axonal regeneration and tissue repair. The development of bioengineered scaffolds that assist in the bridging of such lesion-induced gaps may contribute to the formulation of combination strategies aimed at promoting functional tissue repair. Our previous in vitro investigations have demonstrated the directed axon regeneration and glial migration supporting properties of microstructured collagen scaffold that had been engineered to possess mechanical properties similar to those of spinal cord tissues. Here, the effect of implanting the longitudinally orientated scaffold into unilateral resection injuries (2mm long) of the mid-cervical lateral funiculus of adult rats has been investigated using behavioural and correlative morphological techniques. The resection injuries caused an immediate and long lasting (up to 12 weeks post injury) deficit of food pellet retrieval by the ipsilateral forepaw. Implantation of the orientated collagen scaffold promoted a significant improvement in pellet retrieval by the ipsilateral forepaw at 6 weeks which continued to improve up to 12 weeks post injury. In contrast, implantation of a non-orientated gelatine scaffold did not result in significant functional improvement. Surprisingly, the improved motor performance was not correlated with the regeneration of lesioned axons through the implanted scaffold. This observation supports the notion that biomaterials may support functional recovery by mechanisms other than simple bridging of the lesion site, such as the local sprouting of injured, or even non-injured fibres.
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Affiliation(s)
- Haktan Altinova
- Department of Neurology, Uniklinik Aachen, Aachen, Germany; Department of Neurosurgery, Evangelic Hospital Bethel, Bielefeld, Germany; Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany.
| | - Sven Möllers
- Department of Neurology, Uniklinik Aachen, Aachen, Germany; RNL Europe GmbH, Kleinmachnow, Germany
| | - Tobias Führmann
- Department of Neurology, Uniklinik Aachen, Aachen, Germany; Donnelly Centre for Cellular & Biomolecular Research, University of Toronto, ON, Canada
| | - Ronald Deumens
- Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium; Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany; Jülich-Aachen Research Alliance - Translational Brain Medicine (JARA Brain), Germany
| | - Ahmet Bozkurt
- Department of Plastic Surgery, Reconstructive and Hand Surgery, Burn Centre, Uniklinik Aachen, Aachen, Germany; Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany; Jülich-Aachen Research Alliance - Translational Brain Medicine (JARA Brain), Germany
| | | | | | | | - Joachim Weis
- Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany; Jülich-Aachen Research Alliance - Translational Brain Medicine (JARA Brain), Germany
| | - Gary A Brook
- Department of Neurology, Uniklinik Aachen, Aachen, Germany; Institute for Neuropathology, Uniklinik Aachen, Aachen, Germany; Jülich-Aachen Research Alliance - Translational Brain Medicine (JARA Brain), Germany
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6
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He JY, Zheng XF, Jiang SD, Chen XD, Jiang LS. Sympathetic neuron can promote osteoblast differentiation through BMP signaling pathway. Cell Signal 2013; 25:1372-8. [DOI: 10.1016/j.cellsig.2013.02.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 02/09/2013] [Indexed: 12/30/2022]
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7
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Abstract
Three proteins in mature myelin (Nogo, MAG, and OMgp) have been purported to be critical in causing both regenerative failure and minimal sprouting after CNS injury. However, the role of this repulsive trio in vivo has been controversial. Lee et al., in this issue of Neuron, provide evidence that genetically deleting all three major myelin inhibitors either singly or all together does not result in regeneration after spinal cord lesion, and the minimal sprouting that occurs, when it does, is insufficient to restore meaningful behavior.
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Affiliation(s)
- Jerry Silver
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
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8
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Kofron CM, Liu YT, López-Fagundo CY, Mitchel JA, Hoffman-Kim D. Neurite outgrowth at the biomimetic interface. Ann Biomed Eng 2010; 38:2210-25. [PMID: 20440561 PMCID: PMC3016852 DOI: 10.1007/s10439-010-0054-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 04/21/2010] [Indexed: 10/19/2022]
Abstract
Understanding the cues that guide axons and how we can optimize these cues to achieve directed neuronal growth is imperative for neural tissue engineering. Cells in the local environment influence neurons with a rich combination of cues. This study deconstructs the complex mixture of guidance cues by working at the biomimetic interface--isolating the topographical information presented by cells and determining its capacity to guide neurons. We generated replica materials presenting topographies of oriented astrocytes (ACs), endothelial cells (ECs), and Schwann cells (SCs) as well as computer-aided design materials inspired by the contours of these cells (bioinspired-CAD). These materials presented distinct topographies and anisotropies and in all cases were sufficient to guide neurons. Dorsal root ganglia (DRG) cells and neurites demonstrated the most directed response on bioinspired-CAD materials which presented anisotropic features with 90 degrees edges. DRG alignment was strongest on SC bioinspired-CAD materials followed by AC bioinspired-CAD materials, with more uniform orientation to EC bioinspired-CAD materials. Alignment on replicas was strongest on SC replica materials followed by AC and EC replicas. These results suggest that the topographies of anisotropic tissue structures are sufficient for neuronal guidance. This work is discussed in the context of feature dimensions, morphology, and guidepost hypotheses.
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Affiliation(s)
- Celinda M Kofron
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Center for Biomedical Engineering, Brown University, Box G-B387, Providence, RI 02912, USA
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9
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Richeri A, Bianchimano P, Crutcher KA, Brauer MM. Reduced sympathetic neurite outgrowth on uterine tissue sections from rats treated with estrogen. Cell Tissue Res 2010; 340:287-301. [DOI: 10.1007/s00441-010-0956-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Accepted: 02/25/2010] [Indexed: 12/15/2022]
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10
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Abstract
Following injury to the white matter of the adult mammalian central nervous system (CNS), severed axons fail to regenerate beyond the lesion site. Recent studies have revealed that the CNS white matter contains numerous axon growth inhibitors. These findings can easily lead to the concept that regenerating axons cannot grow in the CNS white matter because of the growth inhibition by these inhibitory molecules. This "misconception" appears to be generally accepted. However, it is erroneous because axons can grow along the CNS white matter very rapidly. Neurons cultured on a slice of adult rat brain can extend their neurites along the white matter tract, while axons of neurons transplanted into the adult rat spinal cord white matter can grow along the CNS white matter very rapidly, at more than 1 mm/day. Not only artificially transplanted neurons, but also in situ CNS neurons can elongate axons linearly within the CNS white matter at this rate. The idea that a CNS neuron can regenerate a severed axon along the CNS white matter has great significance when thinking about reconstruction of original neural networks after focal destruction due to CNS injury.
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11
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Kofron CM, Hoffman-Kim D. Optimization by Response Surface Methodology of Confluent and Aligned Cellular Monolayers for Nerve Guidance. Cell Mol Bioeng 2009; 2:554-572. [PMID: 20625538 DOI: 10.1007/s12195-009-0087-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Anisotropic tissue structures provide guidance for navigating neurons in vitro and in vivo. Here we optimized the generation of comparable anisotropic monolayers of astrocytes, endothelial cells, and Schwann cells as a first step toward determining which properties of anisotropic cells are sufficient for nerve guidance. The statistical experimental design method Design of Experiments and the experimental analysis method Response Surface Methodology were applied to improve efficiency and utility. Factors investigated included dimensions of microcontact printed protein patterns, cell density, and culture duration. Protein patterning spacing had the strongest influence. When cells initially aligned at borders and proliferated to fill in spaces, space between stripes was most effective when it was comparable to cell size. Maximizing the area of adhesive molecule coverage was also important for confluence of these types of cells. When cells adhered and aligned over the width of a stripe and broadened to fill spaces, space width about half the cell width was most effective. These findings suggest that if the mechanism of alignment, alignment at borders or over the width of the stripe, is predetermined and the cell size determined, the optimal size of the micropatterning for aligned monolayers of other cell types can be predicted. This study also demonstrates the effective use of DOE and RSM to probe cellular responses to various and multiple factors toward determination of optimal conditions for a desired cellular response.
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Affiliation(s)
- Celinda M Kofron
- Department of Molecular Pharmacology, Physiology, and Biotechnology and Center for Biomedical Engineering, Brown University, Box G-B387, Providence, RI 02912, USA
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12
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Brösamle C, Halpern ME. Nogo-Nogo receptor signalling in PNS axon outgrowth and pathfinding. Mol Cell Neurosci 2008; 40:401-9. [PMID: 19041397 DOI: 10.1016/j.mcn.2008.10.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Revised: 09/17/2008] [Accepted: 10/15/2008] [Indexed: 12/16/2022] Open
Abstract
The Nogo/Nogo66 receptor signaling pathway has been characterized as inhibitory for axon growth, regeneration, and structural plasticity in the adult mammalian central nervous system. Nogo and its receptor are highly expressed when axon growth is abundant, however, the function of this pathway in neural development is unclear. We have characterized zebrafish Nogo pathway members and examined their role in the developing nervous system using anti-sense morpholinos that inhibit protein synthesis. Depletion of the Nogo66 receptor or a Nogo isoform causes truncated outgrowth of peripheral nervous system (PNS) axons of the head and lateral line. PNS nerves also show increased defasciculation and numerous guidance defects, including axons invading regions along the body flank that are normally avoided. We propose that localized Nogo expression defines inhibitory territories that through repulsion restrict axon growth to permissive regions.
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Affiliation(s)
- Christian Brösamle
- Carnegie Institution of Washington, Department of Embryology, 3520 San Martin Drive, Baltimore, MD 21218, USA.
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13
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Jin Y, Ziemba KS, Smith GM. Axon growth across a lesion site along a preformed guidance pathway in the brain. Exp Neurol 2007; 210:521-30. [PMID: 18261727 DOI: 10.1016/j.expneurol.2007.11.030] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2007] [Revised: 11/30/2007] [Accepted: 11/30/2007] [Indexed: 11/16/2022]
Abstract
Our previous studies showed that axonal outgrowth from dorsal root ganglia (DRG) transplants in the adult rat brain could be directed toward a specific target location using a preformed growth-supportive pathway. This pathway induced axon growth within the corpus callosum across the midline to the opposite hemisphere. In this study, we examined whether such pathways would also support axon growth either through or around a lesion of the corpus callosum. Pathways expressing GFP, NGF, or FGF2/NGF were set up by multiple injections of adenovirus along the corpus callosum. Each pathway included the transplantation site in the left corpus callosum, 2.8 mm away from the midline, and a target site in the right corpus callosum, 2.5 mm from the midline. At the same time, a 1 mm lesion was made through the corpus callosum at the midline in an anteroposterior direction. A group of control animals received lesions and Ad-NGF injections only at the transplant and target sites, without a bridging pathway. DRG cell suspensions from postnatal day 1 or 2 rats were injected at the transplantation site three to four days later. Two weeks after transplantation, brain sections were stained using an anti-CGRP antibody. The CGRP+ axons were counted at 0.5 mm and 1.5 mm from the lesion site in both hemispheres. Few axons grew past the lesion in animals with control pathways, but there was robust axon growth across the lesion site in the FGF2/NGF and NGF-expressing pathways. This study indicated that preformed NGF and combination guidance pathways support more axon growth past a lesion in the adult mammalian brain.
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Affiliation(s)
- Ying Jin
- Department of Physiology, Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536, USA.
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14
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Zurn AD, Bandtlow CE. Regeneration failure in the CNs: cellular and molecular mechanisms. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 557:54-76. [PMID: 16955704 DOI: 10.1007/0-387-30128-3_4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Anne D Zurn
- Department of Experimental Surgery, Lausanne University Hospital, Faculty of Biology and Medicine, Switzerland
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15
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Pettigrew DB, Li YQ, Kuntz C, Crutcher KA. Global expression of NGF promotes sympathetic axonal growth in CNS white matter but does not alter its parallel orientation. Exp Neurol 2007; 203:95-109. [PMID: 16989811 PMCID: PMC2638215 DOI: 10.1016/j.expneurol.2006.07.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 07/18/2006] [Accepted: 07/26/2006] [Indexed: 11/30/2022]
Abstract
Axonal regeneration is normally limited after injuries to CNS white matter. Infusion of neurotrophins has been successful in promoting regenerative growth through injured white matter but this growth generally fails to extend beyond the infusion site. These observations are consistent with a chemotropic effect of these factors on axonal growth and support the prevailing view that neurotrophin-induced axonal regeneration requires the use of gradients, i.e., gradually increasing neurotrophin levels along the target fiber tract. To examine the potential of global overexpression of neurotrophins to promote, and/or modify the orientation of, regenerative axonal growth within white matter, we grafted nerve growth factor (NGF) responsive neurons into the corpus callosum of transgenic mice overexpressing NGF throughout the CNS under control of the promoter for glial fibrillary acidic protein. One week later, glial fibrillary acidic protein and chondroitin sulfate proteoglycan immunoreactivity increased within injured white matter around the grafts. NGF levels were significantly higher in the brains of transgenic compared with non-transgenic mice and further elevated within injury sites compared with the homotypic region of the non-injured side. Although there was minimal outgrowth from neurons grafted into non-transgenic mice, extensive parallel axonal regeneration had occurred within the corpus callosum up to 1.5 mm beyond the astrogliotic scar (the site of maximum NGF expression) in transgenic mice. These results demonstrate that global overexpression of neurotrophins does not override the constraints limiting regenerative growth to parallel orientations and suggest that such factors need not be presented as positive gradients to promote axonal regeneration within white matter.
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MESH Headings
- Animals
- Astrocytes/cytology
- Astrocytes/physiology
- Axotomy
- Brain Injuries/metabolism
- Brain Injuries/physiopathology
- Brain Injuries/therapy
- Brain Injury, Chronic/metabolism
- Brain Injury, Chronic/physiopathology
- Brain Injury, Chronic/therapy
- Central Nervous System/cytology
- Central Nervous System/metabolism
- Chondroitin Sulfate Proteoglycans/metabolism
- Cicatrix/physiopathology
- Cicatrix/prevention & control
- Glial Fibrillary Acidic Protein/genetics
- Glial Fibrillary Acidic Protein/metabolism
- Graft Survival/physiology
- Growth Cones/metabolism
- Growth Cones/ultrastructure
- Mice
- Mice, Transgenic
- Nerve Fibers, Myelinated/metabolism
- Nerve Fibers, Myelinated/ultrastructure
- Nerve Growth Factor/genetics
- Nerve Growth Factor/metabolism
- Nerve Regeneration/physiology
- Promoter Regions, Genetic/genetics
- Superior Cervical Ganglion/cytology
- Superior Cervical Ganglion/metabolism
- Superior Cervical Ganglion/transplantation
- Sympathetic Fibers, Postganglionic/cytology
- Sympathetic Fibers, Postganglionic/metabolism
- Sympathetic Fibers, Postganglionic/transplantation
- Tissue Transplantation
- Up-Regulation/physiology
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Affiliation(s)
- David B. Pettigrew
- Department of Neurosurgery, The Neuroscience Institute, University of Cincinnati College of Medicine, ML 0515, Cincinnati, OH 45267-0515, USA
| | - Ya-Qin Li
- Department of Neurosurgery, The Neuroscience Institute, University of Cincinnati College of Medicine, ML 0515, Cincinnati, OH 45267-0515, USA
| | - Charles Kuntz
- Department of Neurosurgery, The Neuroscience Institute, University of Cincinnati College of Medicine, ML 0515, Cincinnati, OH 45267-0515, USA
| | - Keith A. Crutcher
- Department of Neurosurgery, The Neuroscience Institute, University of Cincinnati College of Medicine, ML 0515, Cincinnati, OH 45267-0515, USA
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16
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Moon LDF, Madani R, Vassalli JD, Bunge MB. Neuronal overexpression of tissue-type plasminogen activator does not enhance sensory axon regeneration or locomotor recovery following dorsal hemisection of adult mouse thoracic spinal cord. J Neurosci Res 2006; 84:1245-54. [PMID: 16917839 DOI: 10.1002/jnr.21019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
CNS axons rarely regenerate spontaneously back to original targets following spinal cord injury (SCI). Neuronal expression of the serine protease tissue-type plasminogen activator (tPA) enhances axon growth in vitro and following PNS injury. Here we test the hypothesis that neuronal overexpression of tPA in adult transgenic mice promotes CNS axon regeneration and functional recovery following SCI. Adult wild-type and transgenic mouse spinal cords were subjected to dorsal hemisection at the level of the T10/T11 vertebrae. PCR confirmed incorporation of the transgene. Immunolabeling revealed overexpression of tPA in transgenic mice in neurons, including large-diameter neurons in lumbar dorsal root ganglia that contribute axons to the dorsal columns. Immunolabeling also revealed the presence of tPA protein within axons juxtaposing the injury site in transgenics but not wild types. In situ zymography revealed abundant enzymatic activity of tPA in gray matter of thoracic spinal cords of transgenics but not wild types. Rotorod locomotor testing revealed no differences between groups in locomotor function up to 21 days postinjury. Transganglionic tracer was injected into the crushed right sciatic nerve 28 days postinjury, and mice were killed 3 days later. There was no evidence for regrowth of ascending dorsal column sensory axons through or beyond the injury site. In conclusion, despite neuronal overexpression of tPA in injured neurons of transgenics, neither locomotor recovery nor regeneration of ascending sensory axons was observed following thoracic dorsal hemisection.
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Affiliation(s)
- L D F Moon
- The Miami Project to Cure Paralysis, Miami, Florida, USA.
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17
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Byrnes KR, Waynant RW, Ilev IK, Wu X, Barna L, Smith K, Heckert R, Gerst H, Anders JJ. Light promotes regeneration and functional recovery and alters the immune response after spinal cord injury. Lasers Surg Med 2005; 36:171-85. [PMID: 15704098 DOI: 10.1002/lsm.20143] [Citation(s) in RCA: 205] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND AND OBJECTIVES Photobiomodulation (PBM) has been proposed as a potential therapy for spinal cord injury (SCI). We aimed to demonstrate that 810 nm light can penetrate deep into the body and promote neuronal regeneration and functional recovery. STUDY DESIGN/MATERIALS AND METHODS Adult rats underwent a T9 dorsal hemisection, followed by treatment with an 810 nm, 150 mW diode laser (dosage = 1,589 J/cm2). Axonal regeneration and functional recovery were assessed using single and double label tract tracing and various locomotor tasks. The immune response within the spinal cord was also assessed. RESULTS PBM, with 6% power penetration to the spinal cord depth, significantly increased axonal number and distance of regrowth (P < 0.001). PBM also returned aspects of function to baseline levels and significantly suppressed immune cell activation and cytokine/chemokine expression. CONCLUSION Our results demonstrate that light, delivered transcutaneously, improves recovery after injury and suggests that light will be a useful treatment for human SCI.
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Affiliation(s)
- Kimberly R Byrnes
- Department of Anatomy, Physiology & Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA.
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Walsh JF, Manwaring ME, Tresco PA. Directional Neurite Outgrowth Is Enhanced by Engineered Meningeal Cell-Coated Substrates. ACTA ACUST UNITED AC 2005; 11:1085-94. [PMID: 16144444 DOI: 10.1089/ten.2005.11.1085] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
After injury to the CNS, the anatomical organization of the tissue is disrupted, posing a barrier to the regeneration of axons. Meningeal cells, a central participant in the CNS tissue response to injury, migrate into the core of the wound site in an unorganized fashion and deposit a disorganized extracellular matrix (ECM) that produces a nonpermissive environment. Previous work in our laboratory has shown that the presentation of nanometer-scale topographic cues to these cells influences their morphological, cytoskeletal, and secreted ECM alignment. In the present study, we provided similar environmental cues to meningeal cells and examined the ability of the composite construct to influence dorsal root ganglion regeneration in vitro. When grown on control surfaces of meningeal cells lacking underlying topographic cues, there was no bias in neurite outgrowth. In contrast, when grown on monolayers of meningeal cells with underlying nanometer-scale topography, neurite outgrowth length was greater and was directed parallel to the underlying surface topography even though there exists an intervening meningeal cell layer. The observed outgrowth was significantly longer than on laminin-coated surfaces, which are considered to be the optimal substrata for promoting outgrowth of dorsal root ganglion neurons in culture. These results suggest that the nanometer-level surface finish of an implanted biomaterial may be used to organize the encapsulation tissue that accompanies the implantation of materials into the CNS. It furthermore suggests a simple approach for improving bridging materials for repair of nerve tracts or for affecting cellular organization at a device-tissue interface.
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Affiliation(s)
- Jennifer F Walsh
- Keck Center for Tissue Engineering, Department of Bioengineering, University of Utah, Salt Lake City, 84112, USA
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Manwaring ME, Walsh JF, Tresco PA. Contact guidance induced organization of extracellular matrix. Biomaterials 2004; 25:3631-8. [PMID: 15020137 DOI: 10.1016/j.biomaterials.2003.10.043] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2003] [Accepted: 10/11/2003] [Indexed: 11/16/2022]
Abstract
The scarring response following injury to the central nervous system disrupts the anatomical organization of nervous tissue posing a barrier to the regeneration of axons. In the present study, using materials with nanometer level surface features we examined whether matrix organization could be controlled by engineering meningeal cell asymmetry. Following 5 days in culture, the organization of meningeal cells along with their cytoskeletal elements and extracellular matrix proteins was evaluated. Meningeal cell morphology was markedly affected by nanometer level substrate topography. Cell alignment increased with increasing surface roughness. In addition, linear arrays of extracellular matrix were expressed that appeared related to cellular orientation. When cultured on substrates with topographical features of less than 10 nm neither cells nor their extracellular matrix showed organizational asymmetry. However, as oriented surface roughness increased, cellular and matrix asymmetrical organization became more pronounced reaching a threshold at 345 nm. These results suggest that biomaterial surface topography or other methods of altering the orientation of cells may be used to engineer orientation into the secreted extracellular matrix and as such may be a potential strategy for developing organized cell-derived matrix as a bridging material for nerve repair or other regenerative applications.
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Affiliation(s)
- Michael E Manwaring
- The Keck Center for Tissue Engineering, Department of Bioengineering, University of Utah, 20 South 2030 East, Building 570, Room 108D, Salt Lake City, UT 84112, USA
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Talac R, Friedman JA, Moore MJ, Lu L, Jabbari E, Windebank AJ, Currier BL, Yaszemski MJ. Animal models of spinal cord injury for evaluation of tissue engineering treatment strategies. Biomaterials 2004; 25:1505-10. [PMID: 14697853 DOI: 10.1016/s0142-9612(03)00497-6] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Tissue engineering approaches to spinal cord injury (SCI) treatment are attractive because they allow for manipulation of native regeneration processes involved in restoration of the integrity and function of damaged tissue. A clinically relevant spinal cord regeneration animal model requires that the model mimics specific pathologic processes that occur in human SCI. This manuscript discusses issues related to preclinical testing of tissue engineering spinal cord regeneration strategies from a number of perspectives. This discussion includes diverse causes, pathology and functional consequences of human SCI, general and species related considerations, technical and animal care considerations, and data analysis methods.
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Affiliation(s)
- R Talac
- Departments of Orthopaedic Surgery and Biomedical Engineering, Mayo Clinic and Mayo Medical School, Medical Sciences Building Room 3-69, 200 1st Street SW, Rochester, MN 55905, USA.
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Affiliation(s)
- Geoffrey Raisman
- Division of Neurobiology, The Norman and Sadie Lee Research Centre, National Institute for Medical Research, Medical Research Council, The Ridgeway, Mill Hill, London NW7 1AA, UK.
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22
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Abstract
In the present study, the influence of astrocyte alignment on the direction and length of regenerating neurites was examined in vitro. Astrocytes were experimentally manipulated by different approaches to create longitudinally aligned monolayers. When cultured on the aligned monolayers, dorsal root ganglion neurites grew parallel to the long axis of the aligned astrocytes and were significantly longer than controls. Engineered monolayers expressed linear arrays of fibronectin, laminin, neural cell adhesion molecule, and chondroitin sulfate proteoglycan that were organized parallel to one another, suggesting that a particular spatial arrangement of these molecules on the astrocyte surface may be necessary to direct nerve regeneration in vivo. In contrast, no bias in directional outgrowth was observed for neurites growing on unorganized monolayers. The results suggest that altering the organization of astrocytes and their scar-associated matrix at the lesion site may be used to influence the direction and the length of adjacent regenerating axons in the damaged brain and spinal cord.
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Affiliation(s)
- Roy Biran
- The Keck Center for Tissue Engineering, Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA
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Snow DM, Smith JD, Cunningham AT, McFarlin J, Goshorn EC. Neurite elongation on chondroitin sulfate proteoglycans is characterized by axonal fasciculation. Exp Neurol 2003; 182:310-21. [PMID: 12895442 DOI: 10.1016/s0014-4886(03)00034-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the developing or regenerating nervous system, migrating growth cones are exposed to regulatory molecules that positively and/or negatively affect guidance. Chondroitin sulfate proteoglycans (CSPGs) are complex macromolecules that are typically negative regulators of growth cone migration in vivo and in vitro. However, in certain cases, neurites sometimes traverse regions expressing relatively high levels of CSPGs, seemingly a paradox. In our continuing efforts to characterize CSPG inhibition in vitro, we manipulated the ratio of CSPGs to growth-promoting laminin-1 to produce a substratum that supports outgrowth of a subpopulation of dorsal root ganglia (DRG) neurites, while still being inhibitory to other populations of DRG neurons [Exp. Neurol. 109 (1990), 111; J. Neurobiol. 51 (2002), 285]. This model comprises a useful tool in the analysis of mechanisms of growth cone guidance and is particularly useful to analyze how CSPGs can be inhibitory under some conditions, and growth permissive under others. We grew embryonic (E9-10) chicken DRG neurons on nervous system-isolated, substratum-bound CSPGs at a concentration that supports an intermittent pattern of outgrowth, alternating with regions adsorbed with growth-promoting laminin-1 alone, and analyzed outgrowth behaviors qualitatively and quantitatively. A novel finding of the study was that DRG neurites that elongated onto CSPGs were predominantly fasciculated, but immediately returned to a defasciculated state upon contact with laminin-1. Further, cursory inspection suggests that outgrowth onto CSPGs may be initially accomplished by pioneer axons, along which subsequent axons migrate. The outgrowth patterns characterized in vitro may accurately reflect outgrowth in vivo in locations where inhibitory CSPGs and growth-promoting molecules are coexpressed, e.g., in the developing retina where fasciculated outgrowth may be instrumental in the guidance of retinal ganglion cells from the periphery to the optic fissure.
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Affiliation(s)
- Diane M Snow
- The University of Kentucky, Department of Anatomy and Neurobiology, Lexington, KY 40536-0298, USA.
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Mladinic M, Wintzer M. Changes in mRNA content of developing opossum spinal cord at stages when regeneration can and cannot occur after injury. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 2002; 40:317-24. [PMID: 12589930 DOI: 10.1016/s0165-0173(02)00214-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The molecular mechanisms responsible for regeneration in the mammalian central nervous system (CNS) are poorly understood. Unlike the situation in adults, in the neonatal opossum, as in other immature mammals, the CNS shows successful regeneration after injury. We have used the isolated opossum CNS as a preparation for studying regeneration. An advantage of the opossum is that its developing spinal cord exhibits a gradient of regeneration in time and space. Thus, the potential for repair becomes lost in the cervical spinal cord when animals reach an age of 12 days or more. Animals up to 17 days of age still show regeneration in less mature lumbar segments of the spinal cord. To identify genes that underlie the process of regeneration we are studying mRNA changes in spinal cords at various stages of development. We have developed techniques for narrowing down the number of candidate genes by performing different gene subtraction experiments and by cross-hybridizing their results. This allowed us to select sequences differentially expressed in regeneration and to eliminate genes unrelated to that process. Our results reveal a number of novel sequences that could be important for spinal cord regeneration, as well as genes already supposed to play a role in regeneration.
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Affiliation(s)
- Miranda Mladinic
- International School for Advanced Studies (SISSA/ISAS), Biophysics Sector, Trieste, Italy.
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Tang S, Qiu J, Nikulina E, Filbin MT. Soluble myelin-associated glycoprotein released from damaged white matter inhibits axonal regeneration. Mol Cell Neurosci 2001; 18:259-69. [PMID: 11591127 DOI: 10.1006/mcne.2001.1020] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The adult, mammalian CNS does not regenerate after injury largely because of a glial scar and inhibitors of regeneration in myelin. To date, two myelin inhibitors, myelin-associated glycoprotein (MAG) and Nogo, both transmembrane proteins, have been identified. No secreted inhibitors of regeneration have been described. However, a proteolytic fragment of MAG (dMAG), consisting of the entire extracellular domain, is readily released from myelin and is found in vivo. Here, we show, first, that a soluble, chimeric form of MAG (MAG-Fc), when secreted from CHO cells in a collagen gel and hence in the absence of a fixed substrate, inhibits/deflects neurite outgrowth from P6 dorsal root ganglion (DRG) neurons. This inhibition was blocked when a MAG monoclonal antibody was included in the gel and a control chimera sialoadhesin-Fc (Sn-Fc), which, like MAG, binds neurons in a sialic acid-dependent manner but does not inhibit axonal growth, had no effect. Using the same assay system we showed that factors secreted from damaged white matter inhibited/deflected neurite outgrowth. This inhibition was neutralized when a MAG monoclonal antibody was included in the gel and there was no inhibition when white matter from a MAG knockout mouse was used. Factors secreted from damaged white matter from wild-type mice had no effect on neurite outgrowth from E18 DRG neurons. These results show that factors secreted from damaged white matter inhibit axonal regeneration and that the majority of inhibitory activity can be accounted for by dMAG. Thus, released dMAG is likely to play an important role in preventing regeneration, immediately after injury before the glial scar forms.
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Affiliation(s)
- S Tang
- Biology Department, Hunter College, 695 Park Avenue, New York, New York, 10021, USA
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Tresco PA. Tissue engineering strategies for nervous system repair. PROGRESS IN BRAIN RESEARCH 2001; 128:349-63. [PMID: 11105693 DOI: 10.1016/s0079-6123(00)28031-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- P A Tresco
- W.M. Keck Center for Tissue Engineering, Department of Bioengineering, University of Utah, Salt Lake City 84112, USA.
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Abstract
It is self-evident that the adult mammalian brain and spinal cord do not regenerate after injury, but recent discoveries have forced a reconsideration of this accepted principle. Advances in our understanding of how the brain develops have provided a rough blueprint for how we may bring about regeneration in the damaged brain. Studies in developmental neurobiology, intracellular signalling and neuroimmunology are bringing the regeneration field closer to success. Notwithstanding these advances, clear and indisputable evidence for adult functional regeneration remains to be shown.
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Affiliation(s)
- P J Horner
- The Laboratory of Genetics, The Salk Institute, La Jolla, California 92037, USA
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