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Signaling pathways involved in NCAM-induced neurite outgrowth. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 663:151-68. [PMID: 20017021 DOI: 10.1007/978-1-4419-1170-4_10] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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52
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Palser AL, Norman AL, Saffell JL, Reynolds R. Neural cell adhesion molecule stimulates survival of premyelinating oligodendrocytes via the fibroblast growth factor receptor. J Neurosci Res 2009; 87:3356-68. [DOI: 10.1002/jnr.22248] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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53
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NCAM-mimetic, FGL peptide, restores disrupted fibroblast growth factor receptor (FGFR) phosphorylation and FGFR mediated signaling in neural cell adhesion molecule (NCAM)-deficient mice. Brain Res 2009; 1309:1-8. [PMID: 19909731 DOI: 10.1016/j.brainres.2009.11.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Revised: 10/08/2009] [Accepted: 11/02/2009] [Indexed: 02/03/2023]
Abstract
Neural cell adhesion molecule (NCAM) is a membrane-bound glycoprotein expressed on the surface of neuronal and glial cells. Previous in vitro studies have demonstrated that NCAM promotes neuronal functions largely via three main interaction partners: the fibroblast growth factor receptor (FGFR), a member of Src family of tyrosine kinases, Fyn and Raf1 kinase which all activate different intracellular signaling pathways. The objective was to clarify, which signaling pathways are being disrupted in NCAM knockout mice and whether FGL peptide is able to restore observed disruptions. Therefore we compared the levels of phosphorylation of FGFR1, Src kinase Fyn, Raf1 kinase, MAP kinases, Akt kinase and calcium/calmodulin-dependent kinases II and IV (CaMKII and CaMKIV) in the hippocampus of NCAM knockout mice to their wild-type littermates. The data of our study show that mice constitutively deficient in all isoforms of NCAM have decreased basal phosphorylation levels of FGFR1 and CaMKII and CaMKIV. Furthermore, NCAM-mimetic, FGL peptide, is found to be able to restore FGFR1, CaMKII and CaMKIV phosphorylation levels and thereby mimic the interactions of NCAM at this receptor in NCAM deficient mice. Also, we found that Fyn(Tyr530), Raf1, MAP kinases and Akt kinase phosphorylation in adult animals is not affected by NCAM deficiency but interestingly, we found an over-expression of another cell adhesion molecule L1. We conclude that in NCAM deficient mice FGFR1-dependent signaling is disrupted and it can be restored by FGL peptide.
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54
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Temporal distribution of mRNA expression levels of various genes in the developing human inferior colliculus. Neurosci Lett 2009; 461:229-34. [DOI: 10.1016/j.neulet.2009.06.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 05/27/2009] [Accepted: 06/08/2009] [Indexed: 01/01/2023]
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55
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Yu W, Lee HK, Hariharan S, Bu W, Ahmed S. Quantitative neurite outgrowth measurement based on image segmentation with topological dependence. Cytometry A 2009; 75:289-97. [PMID: 18951464 DOI: 10.1002/cyto.a.20664] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The study of neuronal morphology and neurite outgrowth has been enhanced by the combination of imaging informatics and high content screening, in which thousands of images are acquired using robotic fluorescent microscopy. To understand the process of neurite outgrowth in the context of neuroregeneration, we used mouse neuroblastoma N1E115 as our model neuronal cell. Six-thousand cellular images of four different culture conditions were acquired with two-channel widefield fluorescent microscopy. We developed a software package called NeuronCyto. It is a fully automatic solution for neurite length measurement and complexity analysis. A novel approach based on topological analysis is presented to segment cells. The detected nuclei were used as references to initialize the level set function. Merging and splitting of cells segments were prevented using dynamic watershed lines based on the constraint of topological dependence. A tracing algorithm was developed to automatically trace neurites and measure their lengths quantitatively on a cell-by-cell basis. NeuronCyto analyzes three important biologically relevant features, which are the length, branching complexity, and number of neurites. The application of NeuronCyto on the experiments of Toca-1 and serum starvation show that the transfection of Toca-1 cDNA induces longer neurites with more complexities than serum starvation.
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Affiliation(s)
- Weimiao Yu
- Imaging Informatics Division, Bioinformatics Institute (BII), Matrix, Singapore.
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56
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Shen Y, Mishra R, Mani S, Meiri KF. Both cell-autonomous and cell non-autonomous functions of GAP-43 are required for normal patterning of the cerebellum in vivo. THE CEREBELLUM 2009; 7:451-66. [PMID: 18777197 DOI: 10.1007/s12311-008-0049-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Growth-associated protein 43 (GAP-43) is required for development of a functional cerebral cortex in vertebrates; however, its role in cerebellar development is not well understood. Recently, we showed that absence of GAP-43 caused defects in proliferation, differentiation, and polarization of cerebellar granule cells. In this paper, we show that absence of GAP-43 causes defects in cerebellar patterning that reflect both cell-autonomous and non-autonomous functions. Cell-autonomous effects of GAP-43 impact precursor proliferation and axon targeting: In its absence, (1) proliferation of granule cell precursors in response to sonic hedgehog and fibroblast growth factor is inhibited, (2) proliferation of neuroepithelial precursors is inhibited, and (3) targeting of climbing fibers to the central lobe is disrupted. Cell non-autonomous effects of GAP-43 impact differentiated Purkinje cells in which GAP-43 has been downregulated: In its absence, both maturation and mediolateral patterning of Purkinje cells are inhibited. Both cell-autonomous and non-autonomous functions of GAP-43 involve its phosphorylation by protein kinase C. GAP-43 is phosphorylated in granule cell precursors in response to sonic hedgehog in vitro, and phosphorylated GAP-43 is also found in proliferating neuroepithelium and climbing fibers. Phosphorylated GAP-43 is specifically enriched in the presynaptic terminals of parallel and climbing fibers that innervate Purkinje cell bodies and dendrites. The cell-autonomous and non-autonomous effects of GAP-43 converge on the central lobe. The multiple effects of GAP-43 on cerebellar development suggest that it is a critical downstream transducer of signaling mechanisms that integrate generation of cerebellar structure with functional parcellation at the central lobe.
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Affiliation(s)
- Yiping Shen
- Department of Anatomy and Cellular Biology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
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57
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Central auditory plasticity after carboplatin-induced unilateral inner ear damage in the chinchilla: up-regulation of GAP-43 in the ventral cochlear nucleus. Hear Res 2009; 255:33-43. [PMID: 19435600 DOI: 10.1016/j.heares.2009.05.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 05/02/2009] [Accepted: 05/04/2009] [Indexed: 11/21/2022]
Abstract
Inner ear damage may lead to structural changes in the central auditory system. In rat and chinchilla, cochlear ablation and noise trauma result in fiber growth and synaptogenesis in the ventral cochlear nucleus (VCN). In this study, we documented the relationship between carboplatin-induced hair cell degeneration and VCN plasticity in the chinchilla. Unilateral application of carboplatin (5mg/ml) on the round window membrane resulted in massive hair cell loss. Outer hair cell degeneration showed a pronounced basal-to-apical gradient while inner hair cell loss was more equally distributed throughout the cochlea. Expression of the growth associated protein GAP-43, a well-established marker for synaptic plasticity, was up-regulated in the ipsilateral VCN at 15 and 31 days post-carboplatin, but not at 3 and 7 days. In contrast, the dorsal cochlear nucleus showed only little change. In VCN, the high-frequency area dorsally showed slightly yet significantly stronger GAP-43 up-regulation than the low-frequency area ventrally, possibly reflecting the high-to-low frequency gradient of hair cell degeneration. Synaptic modification or formation of new synapses may be a homeostatic process to re-adjust mismatched inputs from two ears. Alternatively, massive fiber growth may represent a deleterious process causing central hyperactivity that leads to loudness recruitment or tinnitus.
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58
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Hsu JYC, Stein SA, Xu XM. Abnormal growth of the corticospinal axons into the lumbar spinal cord of the hyt/hyt mouse with congenital hypothyroidism. J Neurosci Res 2009; 86:3126-39. [PMID: 18543337 DOI: 10.1002/jnr.21750] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Thyroid hormone deficiency may cause severe neurological disorders resulting from developmental deficits of the central nervous system. The mutant hyt/hyt mouse, characterized by fetal-onset, life-long hypothyroidism resulting from a point mutation of the thyroid-stimulating hormone receptor of the thyroid gland, displays a variety of abnormalities in motor behavior that are likely associated with dysfunctions of specific brain regions and a defective corticospinal tract (CST). To test the hypothesis that fetal and neonatal hypothyroidism cause abnormal CST development, the growth of the CST was investigated in hypothyroid hyt/hyt mice and their euthyroid progenitors, the BALB/cByJ mice. Anterograde labeling with biotinylated dextran amine demonstrated a decrease in the number of CST axons in the hyt/hyt mouse at the first lumbar level at postnatal day (P) 10. After retrograde tracing with fast blue (FB), fewer FB-labeled neurons were found in the motor cortex, the red nucleus, and the lateral vestibular nucleus of the hyt/hyt mouse. At the fourth lumbar level, the hyt/hyt mouse also showed smaller CST cross-sectional areas and significantly lower numbers of unmyelinated axons, myelinated axons, and growth cones within the CST during postnatal development. At P10, the hyt/hyt mouse demonstrated significantly lower immunoreactivity of embryonic neural cell adhesion molecule in the CST at the seventh cervical level, whereas the expression of growth-associated protein 43 remained unchanged. Our study demonstrated an abnormal development of the CST in the hyt/hyt mouse, manifested by reduced axon quantity and retarded growth pattern at the lumbar spinal cord.
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Affiliation(s)
- Jung-Yu C Hsu
- Department of Anatomy and Neurobiology, Saint Louis University School of Medicine, St Louis, MO, USA.
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59
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Chang IY, Kim SW, Lee KJ, Yoon SP. Calbindin D-28k, Parvalbumin and Calcitonin Gene-Related Peptide Immunoreactivity in the Canine Spinal Cord. Anat Histol Embryol 2008; 37:446-51. [DOI: 10.1111/j.1439-0264.2008.00879.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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60
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61
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Sachana M, Flaskos J, Hargreaves AJ. Effects of Chlorpyrifos and Chlorpyrifos-Methyl on the Outgrowth of Axon-Like Processes, Tubulin, and GAP-43 in N2a Cells. Toxicol Mech Methods 2008; 15:405-10. [DOI: 10.1080/15376520500194767] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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62
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Zhao HS, Chen SJ, Wu N, Wang XQ, Yin ZQ, Wang Y. LEDGFp52 controls rat retinal ganglion cell neurite growth in culture and regulates specific neuronal growth-associated genes and protein production. J Int Med Res 2008; 36:815-29. [PMID: 18652779 DOI: 10.1177/147323000803600425] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We investigated the regulation of primary neurite growth and expression of specific growth-associated genes by lens epithelium-derived growth factor (LEDGF) in rat retinal ganglion cells (RGCs). A pAd-LEDGFp52 adenovirus vector and a siRNA-LEDGFp52 eucaryotic expression vector were transfected into cultured RGCs. Transfection with pAd-LEDGFp52 significantly increased the number of neurites and their lengths compared with untransfected control RGCs. The expression of growth associated protein 43 (GAP43), microtubule-associated protein 2 (MAP2), and low-molecular-weight neurofilament (NF-L) genes and proteins were also significantly up-regulated. In contrast, the introduction of siRNA-LEDGFp52 significantly decreased the number and length of neurites, and significantly down-regulated the expression GAP43, NF-L and MAP2 genes and proteins compared with controls. Our findings suggest that LEDGFp52 might act as a dendritic arborization gene as well as an axonal elongation gene in RGCs and that it might be beneficial to the functional recovery of regenerating RGCs.
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Affiliation(s)
- H S Zhao
- Southwest Eye Hospital/Southwest Hospital, Third Military Medical University, Chongqing, China
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63
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A crosslinking analysis of GAP-43 interactions with other proteins in differentiated N1E-115 cells. Int J Mol Sci 2008; 9:1753-1771. [PMID: 19325830 PMCID: PMC2635752 DOI: 10.3390/ijms9091753] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 09/03/2008] [Accepted: 09/13/2008] [Indexed: 11/16/2022] Open
Abstract
It has been suggested that GAP-43 (growth-associated protein) binds to various proteins in growing neurons as part of its mechanism of action. To test this hypothesis in vivo, differentiated N1E-115 neuroblastoma cells were labeled with [35S]-amino acids and were treated with a cleavable crosslinking reagent. The cells were lysed in detergent and the lysates were centrifuged at 100,000 × g to isolate crosslinked complexes. Following cleavage of the crosslinks and analysis by two-dimensional gel electrophoresis, it was found that the crosslinker increased the level of various proteins, and particularly actin, in this pellet fraction. However, GAP-43 was not present, suggesting that GAP-43 was not extensively crosslinked to proteins of the cytoskeleton and membrane skeleton and did not sediment with them. GAP-43 also did not sediment with the membrane skeleton following nonionic detergent lysis. Calmodulin, but not actin or other proposed interaction partners, co-immunoprecipitated with GAP-43 from the 100,000 × g supernatant following crosslinker addition to cells or cell lysates. Faint spots at 34 kDa and 60 kDa were also present. Additional GAP-43 was recovered from GAP-43 immunoprecipitation supernatants with anti-calmodulin but not with anti-actin. The results suggest that GAP-43 is not present in complexes with actin or other membrane skeletal or cytoskeletal proteins in these cells, but it is nevertheless possible that a small fraction of the total GAP-43 may interact with other proteins.
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64
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Ranasinghe HS, Williams CE, Christophidis LJ, Mitchell MD, Fraser M, Scheepens A. Proteolytic activity during cortical development is distinct from that involved in hypoxic ischemic injury. Neuroscience 2008; 158:732-44. [PMID: 18809469 DOI: 10.1016/j.neuroscience.2008.07.069] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 06/19/2008] [Accepted: 07/03/2008] [Indexed: 11/19/2022]
Abstract
Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases involved in brain development and the etiology of adult cerebral injuries. In this study, we determined the MMP-2 and 9 responses following hypoxic ischemia (HI) injury in the developing brain. First, we characterized the developmental changes of MMP activity in the rat brain from embryonic day 18 (E18) to postnatal day 120 (P120). MMP-2 activity was high from E18 to P3 and decreased with age (P< or =0.001), while MMP-9 activity was not detectable. MMP-2 immunoreactivity was closely associated with differentiating cortical plate and subplate neurons. Next, we characterized the proteolytic changes after unilateral HI brain injury in 3- (P3) and 21- (P21) day-old rats. Zymography revealed that in the P21 rat brain, MMP-9 activity (150 and 92 kDa forms) was increased at 6 h and remained elevated 24 h post-injury in the ipsilateral injured hemisphere (P< or =0.001), whereas there was a gradual increase in MMP-2 (65 kDa) activity, reaching a peak at 5 days (P< or =0.001). Similarly, quantitative real time polymerase chain reaction (qRT-PCR) indicated significant elevations in MMP-9 and MMP-2 mRNA expression in the injured cortex (P< or =0.05) and hippocampus (P< or =0.05) at 1 and 5 days post-injury, respectively in the P21 rat brain. In the P3 rat brain, zymography results revealed that both pro (92 kDa) and cleaved (87 kDa) MMP-9 activities were upregulated in the ipsilateral injured hemisphere from 6 h to 1 day after injury (P< or =0.001). In contrast, cleaved MMP-2 (60 kDa) was only moderately upregulated at 6 h (P< or =0.01), while pro MMP-2 (65 kDa) levels were unaffected. MMP-9 mRNA expression was also increased at 6 h (P< or =0.05) following injury at P3, whereas MMP-2 expression remained unchanged compared with the uninjured contralateral hemisphere. Immunohistochemistry indicated that MMP-9 protein expression was localized predominantly to neurons and peri-vascular astrocytes in the affected regions at early time points, whereas MMP-2 was present on reactive astrocytes surrounding the infarct at later time points. Together, these results indicate that MMP-2 may be primarily associated with the development and differentiation of cortical plate neurons and wound recovery processes. Conversely, MMP-9 appeared to be associated with more acute processes during the period of lesion development.
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Affiliation(s)
- H S Ranasinghe
- Liggins Institute, University of Auckland, 2-6 Park Avenue, Grafton, Auckland, New Zealand
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65
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Korshunova I, Mosevitsky M. Role of the Growth-associated Protein GAP-43 in NCAM-mediated Neurite Outgrowth. Neurochem Res 2008. [DOI: 10.1007/s11064-008-9800-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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66
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Sidiropoulou E, Sachana M, Flaskos J, Harris W, Hargreaves AJ, Woldehiwet Z. Diazinon oxon affects the differentiation of mouse N2a neuroblastoma cells. Arch Toxicol 2008; 83:373-80. [DOI: 10.1007/s00204-008-0339-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Accepted: 07/03/2008] [Indexed: 12/31/2022]
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67
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68
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A critical importance of polyamine site in NMDA receptors for neurite outgrowth and fasciculation at early stages of P19 neuronal differentiation. Exp Cell Res 2008; 314:2603-17. [PMID: 18586028 DOI: 10.1016/j.yexcr.2008.06.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 05/27/2008] [Accepted: 06/05/2008] [Indexed: 01/16/2023]
Abstract
We have investigated the role of N-methyl-d-aspartate receptors (NMDARs) and gamma-aminobutyric acid receptors type A (GABA(A)Rs) at an early stage of P19 neuronal differentiation. The subunit expression was profiled in 24-hour intervals with RT-PCR and functionality of the receptors was verified via fluo-3 imaging of Ca(2+) dynamics in the immature P19 neurons showing that both NMDA and GABA excite neuronal bodies, but only polyamine-site sensitive NMDAR stimulation leads to enhanced Ca(2+) signaling in the growth cones. Inhibition of NR1/NR2B NMDARs by 1 muM ifenprodil severely impaired P19 neurite extension and fasciculation, and this negative effect was fully reversible by polyamine addition. In contrast, GABA(A)R antagonism by a high dose of 200 microM bicuculline had no observable effect on P19 neuronal differentiation and fasciculation. Except for the differential NMDAR and GABA(A)R profiles of Ca(2+) signaling within the immature P19 neurons, we have also shown that inhibition of NR1/NR2B NMDARs strongly decreased mRNA level of NCAM-180, which has been previously implicated as a regulator of neuronal growth cone protrusion and neurite extension. Our data thus suggest a critical role of NR1/NR2B NMDARs during the process of neuritogenesis and fasciculation of P19 neurons via differential control of local growth cone Ca(2+) surges and NCAM-180 signaling.
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69
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Povlsen GK, Ditlevsen DK. WITHDRAWN: The Neural Cell Adhesion Molecule NCAM and Lipid Rafts. Neurochem Res 2008. [PMID: 18548347 DOI: 10.1007/s11064-008-9759-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2008] [Indexed: 11/28/2022]
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70
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Wang PY, Seabold GK, Wenthold RJ. Synaptic adhesion-like molecules (SALMs) promote neurite outgrowth. Mol Cell Neurosci 2008; 39:83-94. [PMID: 18585462 DOI: 10.1016/j.mcn.2008.05.019] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 05/12/2008] [Accepted: 05/26/2008] [Indexed: 11/15/2022] Open
Abstract
SALMs are a family of five adhesion molecules whose expression is largely restricted to the CNS. Initial reports showed that SALM1 functions in neurite outgrowth while SALM2 is involved in synapse formation. To investigate the function of SALMs in detail, we asked if all five are involved in neurite outgrowth. Expression of epitope-tagged proteins in cultured hippocampal neurons showed that SALMs are distributed throughout neurons, including axons, dendrites, and growth cones. Over-expression of each SALM resulted in enhanced neurite outgrowth, but with different phenotypes. Neurite outgrowth could be reduced by applying antibodies targeting the extracellular leucine rich regions of SALMs and with RNAi. Through over-expression of deletion constructs, we found that the C-terminal PDZ binding domains of SALMs 1-3 are required for most aspects of neurite outgrowth. In addition, by using a chimera of SALMs 2 and 4, we found that the N-terminus is also involved in neurite outgrowth.
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Affiliation(s)
- Philip Y Wang
- Laboratory of Neurochemistry, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
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71
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Williams G, Wood A, Williams EJ, Gao Y, Mercado ML, Katz A, Joseph-McCarthy D, Bates B, Ling HP, Aulabaugh A, Zaccardi J, Xie Y, Pangalos MN, Walsh FS, Doherty P. Ganglioside Inhibition of Neurite Outgrowth Requires Nogo Receptor Function. J Biol Chem 2008; 283:16641-52. [DOI: 10.1074/jbc.m802067200] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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72
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Association of Gap-43 (neuromodulin) with microtubule-associated protein MAP-2 in neuronal cells. Biochem Biophys Res Commun 2008; 371:679-83. [PMID: 18455509 DOI: 10.1016/j.bbrc.2008.04.119] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Accepted: 04/19/2008] [Indexed: 11/21/2022]
Abstract
Gap-43 (B-50, neuromodulin) is a presynaptic protein implicated in axonal growth, neuronal differentiation, plasticity, and regeneration. Its activities are regulated by its dynamic interactions with various neuronal proteins, including actin and brain spectrin. Recently we have shown that Gap-43 co-localizes with an axonal protein DPYSL-3 in primary cortical neurons. In the present study we provide evidence that Gap-43 co-localizes and potentially interacts with microtubule-associated protein MAP-2 in adult and fetal rat brain, as well as in primary neuronal cultures. Our studies suggest that this interaction may be developmentally regulated.
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73
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Hansen SM, Li S, Bock E, Berezin V. WITHDRAWN: Synthetic NCAM-derived Ligands of the Fibroblast Growth Factor Receptor. Neurochem Res 2008. [PMID: 18427984 DOI: 10.1007/s11064-008-9707-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2008] [Indexed: 10/22/2022]
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74
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Gómez M, Hernández ML, Pazos MR, Tolón RM, Romero J, Fernández-Ruiz J. Colocalization of CB1 receptors with L1 and GAP-43 in forebrain white matter regions during fetal rat brain development: evidence for a role of these receptors in axonal growth and guidance. Neuroscience 2008; 153:687-99. [PMID: 18400407 DOI: 10.1016/j.neuroscience.2008.02.038] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Revised: 01/19/2008] [Accepted: 02/05/2008] [Indexed: 12/13/2022]
Abstract
There is recent evidence supporting the notion that the cannabinoid signaling system plays a modulatory role in the regulation of cell proliferation and migration, survival of neural progenitors, neuritic elongation and guidance, and synaptogenesis. This assumption is based on the fact that cannabinoid 1-type receptors (CB(1) receptors) and their ligands emerge early in brain development and are abundantly expressed in certain brain regions that play key roles in these processes. We have recently presented in vivo evidence showing that this modulatory action might be exerted through regulating the synthesis of the cell adhesion molecule L1 that is also a key element for those processes. To further explore this issue, we conducted here immunohistochemical studies aimed at determining the cellular substrates of CB(1) receptor-L1 interactions in the rat brain during late fetal development. In this period, we previously found that the activation of CB(1) receptors increased L1 synthesis in several forebrain white matter regions but not in gray matter areas. Using double labeling studies, we observed here colocalization of both proteins in fiber tracts including the corpus callosum, the adjacent subcortical white matter, the internal capsule and the anterior commissure. Experiments conducted with cultures of fetal rat cortical nerve cells revealed that L1 is present mainly in neurons but not in glial cells. This fact, together with the results obtained in the double labeling studies, would indicate that L1 and CB(1) receptors should possibly be present in axons elongating through these white matter tracts, or, alternatively, in migrating neurons. Further experiments confirmed the presence of CB(1) receptors in elongating axons, since these receptors colocalized with growth-associated protein 43 (GAP-43), a marker of growth cones, but not with synaptophysin, a marker of active synaptic terminals, in the same forebrain white matter regions. Lastly, using cultured fetal rat cortical neurons, we also observed that the activation of cannabinoid receptors increased the levels of the full-length L1 and altered those of some active proteolytic fragments of this protein whose generation has been associated with specific steps in the process of neuritic elongation in cultured neurons. In summary, we have demonstrated that the effects caused by cannabinoid agonists on L1 are facilitated by the colocalization of this cell adhesion molecule with CB(1) receptors in several forebrain white matter regions during fetal brain development. We have provided strong evidence that this phenomenon occurs in axons elongating through these white matter tracts, and we have explored in vitro how cannabinoid receptors influence L1 levels. Considering the role played by L1 in different events related to neural development, our observations support the occurrence of a physiological mechanism by which the cannabinoid system might regulate the process of axonal growth and guidance through regulating the synthesis and function of L1.
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Affiliation(s)
- M Gómez
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain
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75
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Ditlevsen DK, Povlsen GK, Berezin V, Bock E. NCAM-induced intracellular signaling revisited. J Neurosci Res 2008; 86:727-43. [DOI: 10.1002/jnr.21551] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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76
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Abstract
Vesicle fusion is a ubiquitous biological process involved in general membrane trafficking and a variety of specialized events, for example release of neurotransmitters and hormones, sperm acrosome exocytosis, plasma membrane repair and neurite outgrowth. Many vesicle fusion events have long been known to be activated by phospholipases and products of their activity, such as polyunsaturated arachidonic acid. Polyunsaturated fatty acids (PUFAs) have been proposed to have a number of multiple effectors, including ion channels and the cytoskeleton, but the precise mechanism of PUFA action is still unclear. It was recently reported that omega-3 and omega-6 PUFAs can act on syntaxin, a plasma membrane protein directly involved in vesicle fusion. In this review, we will discuss the role of this new mode of PUFA action in exocytosis.
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Affiliation(s)
- Frédéric Darios
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge, UK
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77
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Albright MJ, Weston MC, Inan M, Rosenmund C, Crair MC. Increased thalamocortical synaptic response and decreased layer IV innervation in GAP-43 knockout mice. J Neurophysiol 2007; 98:1610-25. [PMID: 17581849 DOI: 10.1152/jn.00219.2007] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The growth-associated protein, GAP-43, is an axonally localized neuronal protein with high expression in the developing brain and in regenerating neurites. Mice that lack GAP-43 (GAP-43 -/-) fail to form a whisker-related barrel map. In this study, we use GAP-43 -/- mice to examine GAP-43 synaptic function in the context of thalamocortical synapse development and cortical barrel map formation. Examination of thalamocortical synaptic currents in an acute brain slice preparation and in autaptic thalamic neurons reveals that GAP-43 -/- synapses have larger alpha-amino-3-hydroxyl-5-methyl-4-isoxazolepropionate receptor (AMPAR)-mediated currents than controls despite similar AMPAR function and normal probability of vesicular release. Interestingly, GAP-43 -/- synapses are less sensitive to blockade by a competitive glutamate receptor antagonist, suggesting higher levels of neurotransmitter in the cleft during synaptic transmission. Field excitatory postsynaptic potentials (EPSPs) from GAP-43 -/- thalamocortical synapses reveal a reduced fiber response, and anatomical analysis shows reduced thalamic innervation of barrel cortex in GAP-43 -/- mice. Despite this fact synaptic responses in the field EPSPs are similar in GAP-43 -/- mice and wild-type littermate controls, and the ratio of AMPAR-mediated to N-methyl-d-aspartate receptor (NMDAR)-mediated currents (AMPAR:NMDAR ratio) is larger than normal. This suggests that GAP-43 -/- mice form fewer thalamocortical synapses in layer IV because of decreased anatomical innervation of the cortex, but the remaining contacts are individually stronger possibly due to increased neurotransmitter concentration in the synaptic cleft. Together, these results indicate that in addition to its well known role in axonal pathfinding GAP-43 plays a functional role in regulating neurotransmitter release.
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Affiliation(s)
- Michael J Albright
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA
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78
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79
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Zakharov VV, Mosevitsky MI. M-calpain-mediated cleavage of GAP-43 near Ser41 is negatively regulated by protein kinase C, calmodulin and calpain-inhibiting fragment GAP-43-3. J Neurochem 2007; 101:1539-51. [PMID: 17326767 DOI: 10.1111/j.1471-4159.2007.04452.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Neuronal protein GAP-43 performs multiple functions in axon guidance, synaptic plasticity and regulation of neuronal death and survival. However, the molecular mechanisms of its action in these processes are poorly understood. We have shown that in axon terminals GAP-43 is a substrate for calcium-activated cysteine protease m-calpain, which participates in repulsion of axonal growth cones and induction of neuronal death. In pre-synaptic terminals in vivo, in synaptosomes, and in vitro, m-calpain cleaved GAP-43 in a small region near Ser41, on either side of this residue. In contrast, micro-calpain cleaved GAP-43 in vitro at several other sites, besides Ser41. Phosphorylation of Ser41 by protein kinase C or GAP-43 binding to calmodulin strongly suppressed GAP-43 proteolysis by m-calpain. A GAP-43 fragment, lacking about forty N-terminal residues (named GAP-43-3), was produced by m-calpain-mediated cleavage of GAP-43 and inhibited m-calpain, but not micro-calpain. This fragment prevented complete cleavage of intact GAP-43 by m-calpain as a negative feedback. GAP-43-3 also blocked m-calpain activity against casein, a model calpain substrate. This implies that GAP-43-3, which is present in axon terminals in high amount, can play important role in regulation of m-calpain activity in neurons. We suggest that GAP-43-3 and another (N-terminal) GAP-43 fragment produced by m-calpain participate in modulation of neuronal response to repulsive and apoptotic signals.
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Affiliation(s)
- Vladislav V Zakharov
- Division of Molecular and Radiation Biophysics, Petersburg Nuclear Physics Institute of Russian Academy of Sciences, Gatchina, Leningrad District, Russia.
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80
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Yamanaka H, Obata K, Kobayashi K, Dai Y, Fukuoka T, Noguchi K. Alteration of the cell adhesion molecule L1 expression in a specific subset of primary afferent neurons contributes to neuropathic pain. Eur J Neurosci 2007; 25:1097-111. [PMID: 17331206 PMCID: PMC1891330 DOI: 10.1111/j.1460-9568.2007.05344.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The cell adhesion molecule L1 (L1-CAM) plays important functional roles in the developing and adult nervous systems. Here we show that peripheral nerve injury induced dynamic post-transcriptional alteration of L1-CAM in the rat dorsal root ganglia (DRGs) and spinal cord. Sciatic nerve transection (SCNT) changed the expression of L1-CAM protein but not L1-CAM mRNA. In DRGs, SCNT induced accumulation of the L1-CAM into the surface of somata, which resulted in the formation of immunoreactive ring structures in a number of unmyelinated C-fiber neurons. These neurons with L1-CAM-immunoreactive ring structures were heavily colocalized with phosphorylated p38 MAPK. Western blot analysis revealed the increase of full-length L1-CAM and decrease of fragments of L1-CAM after SCNT in DRGs. Following SCNT, L1-CAM-immunoreactive profiles in the dorsal horn showed an increase mainly in pre-synaptic areas of laminae I–II with a delayed onset and colocalized with growth-associated protein 43. In contrast to DRGs, SCNT increased the proteolytic 80-kDa fragment of L1-CAM and decreased full-length L1-CAM in the spinal cord. The intrathecal injection of L1-CAM antibody for the extracellular domain of L1-CAM inhibited activation of p38 MAPK and emergence of ring structures of L1-CAM immunoreactivity in injured DRG neurons. Moreover, inhibition of extracellular L1-CAM binding by intrathecal administration of antibody suppressed the mechanical allodynia and thermal hyperalgesia induced by partial SCNT. Collectively, these data suggest that the modification of L1-CAM in nociceptive pathways might be an important pathomechanism of neuropathic pain.
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Affiliation(s)
- Hiroki Yamanaka
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
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81
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Stupp T, Naskar R, Thanos S. Growth-associated protein-43 expression in the lens of rats and primates. Neuroreport 2007; 18:7-11. [PMID: 17259852 DOI: 10.1097/wnr.0b013e3280109e9d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Growth-associated protein-43 is a specific neuronal protein that regulates differentiation, growth and plasticity. In the present study, growth-associated protein-43 expression was studied in the lens of rats and primates (including man) at different postnatal ages by immunoblotting, immunohistochemistry and quantitative real-time polymerase chain reaction. Growth-associated protein-43 was expressed at all ages in primates and in developing, but not in adult rats. We demonstrate that the lens - a tissue that is devoid of nerves - expresses growth-associated protein-43 throughout life in primates, and in rats during development but not in adulthood. These results suggest that growth-associated protein-43 is involved in differentiation processes also outside the nervous system.
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Affiliation(s)
- Tobias Stupp
- Department of Experimental Ophthalmology, University Eye Hospital, Münster, Germany
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82
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Valdez SR, Patterson SI, Ezquer ME, Torrecilla M, Lama MC, Seltzer AM. Acute sublethal global hypoxia induces transient increase of GAP-43 immunoreactivity in the striatum of neonatal rats. Synapse 2007; 61:124-37. [PMID: 17146769 DOI: 10.1002/syn.20353] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We assessed immunoreactivity (IR) in the cerebral cortex (CC), hippocampus (Hipp), and striatum (ST) of a growth-associated protein, GAP-43, and of proteins of the synaptic vesicle fusion complex: VAMP-2, Syntaxin-1, and SNAP-25 (SNARE proteins) throughout postnatal development of rats after submitting the animals to acute global postnatal hypoxia (6.5% O(2), 70 min) at postnatal day 4 (PND4). In the CC only the IR of the SNARE protein SNAP-25 increased significantly with age. The hypoxic animals showed the same pattern of IR for SNAP-25, although with lower levels at PND11, and also a significant increase of VAMP-2. SNAP-25 (control): PND11 P < 0.001 vs. PND18, 25, and 40, SNAP-25 (hypoxic): P < 0.001 vs. PND18, 25, and 40; VAMP-2 (hypoxic): P < 0.05 PND11 vs. PND18, and P < 0.01 vs. PND25 and PND40; one-way ANOVA and Bonferroni post-test. In the Hipp, SNAP-25 and syntaxin-1 increased significantly with age, reaching a plateau at PND25 through PND40 in control animals (one-way ANOVA: syntaxin-1: P = 0.043; Bonferroni: NS; SNAP-25: P = 0.013; Bonferroni: P < 0.01 PND11 vs. PND40). Hypoxic rats showed higher levels of significance in the one-way ANOVA than controls (syntaxin-1: P = 0.009; Bonferroni: P < 0.05 PND11 vs. PND25 and P < 0.001 PND11 vs. PND40). In the ST, GAP-43 differed significantly among hypoxic and control animals and the two-way ANOVA revealed significant differences with age (F = 3.23; P = 0.037) and treatment (F = 4.84; P = 0.036). VAMP-2 expression also reached statistical significance when comparing control and treated animals (F = 6.25, P = 0.018) without changes regarding to age. Elevated plus maze test performed at PND40 indicated a lower level of anxiety in the hypoxic animals. At adulthood (12 weeks) learning, memory and locomotor abilities were identical in both groups of animals. With these results, we demonstrate that proteins of the presynaptic structures of the ST are sensitive to acute disruption of homeostatic conditions, such as a temporary decrease of the O(2) concentration. Modifications in the activity of these proteins could contribute to the long term altered responses to stress due to acute hypoxic insult in the neonatal period.
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Affiliation(s)
- Susana R Valdez
- IMBECU-CRICYT, Centro Regional de Investigaciones Científicas y Tecnológicas, Mendoza, Argentina
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83
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Korshunova I, Novitskaya V, Kiryushko D, Pedersen N, Kolkova K, Kropotova E, Mosevitsky M, Rayko M, Morrow JS, Ginzburg I, Berezin V, Bock E. GAP-43 regulates NCAM-180-mediated neurite outgrowth. J Neurochem 2006; 100:1599-612. [PMID: 17212696 DOI: 10.1111/j.1471-4159.2006.04316.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The neural cell adhesion molecule (NCAM), and the growth-associated protein (GAP-43), play pivotal roles in neuronal development and plasticity and possess interdependent functions. However, the mechanisms underlying the functional association of GAP-43 and NCAM have not been elucidated. In this study we show that (over)expression of GAP-43 in PC12E2 cells and hippocampal neurons strongly potentiates neurite extension, both in the absence and in the presence of homophilic NCAM binding. This potentiation is crucially dependent on the membrane association of GAP-43. We demonstrate that phosphorylation of GAP-43 by protein kinase C (PKC) as well as by casein kinase II (CKII) is important for the NCAM-induced neurite outgrowth. Moreover, our results indicate that in the presence of GAP-43, NCAM-induced neurite outgrowth requires functional association of NCAM-180/spectrin/GAP-43, whereas in the absence of GAP-43, the NCAM-140/non-receptor tyrosine kinase (Fyn)-associated signaling pathway is pivotal. Thus, expression of GAP-43 presumably acts as a functional switch for NCAM-180-induced signaling. This suggests that under physiological conditions, spatial and/or temporal changes of the localization of GAP-43 and NCAM on the cell membrane may determine the predominant signaling mechanism triggered by homophilic NCAM binding: NCAM-180/spectrin-mediated modulation of the actin cytoskeleton, NCAM-140-mediated activation of Fyn, or both.
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Affiliation(s)
- Irina Korshunova
- Protein Laboratory, Institute of Molecular Pathology, University of Copenhagen, DK-2200 Copenhagen, Denmark.
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84
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Hewett SJ, Bell SC, Hewett JA. Contributions of cyclooxygenase-2 to neuroplasticity and neuropathology of the central nervous system. Pharmacol Ther 2006; 112:335-57. [PMID: 16750270 DOI: 10.1016/j.pharmthera.2005.04.011] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Accepted: 04/19/2005] [Indexed: 01/08/2023]
Abstract
Cyclooxygenase (COX) enzymes, or prostaglandin-endoperoxide synthases (PTGS), are heme-containing bis-oxygenases that catalyze the first committed reaction in metabolism of arachidonic acid (AA) to the potent lipid mediators, prostanoids and thromboxanes. Two isozymes of COX enzymes (COX-1 and COX-2) have been identified to date. This review will focus specifically on the neurobiological and neuropathological consequences of AA metabolism via the COX-2 pathway and discuss the potential therapeutic benefit of COX-2 inhibition in the setting of neurological disease. However, given the controversy surrounding the use of COX-2 selective inhibitors with respect to cardiovascular health, it will be important to move beyond COX to identify which down-stream effectors are responsible for the deleterious and/or potentially protective effects of COX-2 activation in the setting of neurological disease. Important advances toward this goal are highlighted herein. Identification of unique effectors in AA metabolism could direct the development of new therapeutics holding significant promise for the prevention and treatment of neurological disorders.
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Affiliation(s)
- Sandra J Hewett
- Department of Neuroscience MC3401, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA.
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85
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von Schassen C, Fester L, Prange-Kiel J, Lohse C, Huber C, Böttner M, Rune GM. Oestrogen synthesis in the hippocampus: role in axon outgrowth. J Neuroendocrinol 2006; 18:847-56. [PMID: 17026534 DOI: 10.1111/j.1365-2826.2006.01484.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ovarian oestrogens have been postulated to be neuroprotective. It has also been shown that considerable amounts of oestrogens are synthesised in hippocampal neurones. In the present study, we focused on a potential role of hippocampus-derived oestradiol compared to gonad-derived oestradiol on axon outgrowth of hippocampal neurones. To address the role of hippocampus-derived oestradiol, we inhibited oestrogen synthesis by treatment of neonatal hippocampal cell cultures with letrozole, a specific aromatase inhibitor. As an alternative, we used siRNA against steroidogenic acute regulatory protein (StAR). Axon outgrowth and GAP-43 expression were significantly down-regulated in response to letrozole and in siRNA-StAR transfected cells. The effects after inhibition of oestrogen synthesis in response to letrozole and in siRNA-StAR transfected cells were reversed by oestrogen supplementation. No difference was found between ovariectomised animals, cycling animals at pro-oestrus and ovariectomised and subsequently oestradiol-treated animals. However, high pharmacological doses of oestradiol promoted axon outgrowth, which was possible to abolish by the oestrogen receptor antagonist ICI 182,780. Our results show that oestradiol-induced neurite outgrowth is very likely mediated by genomic oestrogen receptors and requires higher doses of oestradiol than physiological serum concentrations derived from the gonads.
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Affiliation(s)
- C von Schassen
- Institute of Anatomy I, Cellular Neurobiology, University Medical Center, Hamburg, Germany
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86
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Sanchez-Heras E, Howell FV, Williams G, Doherty P. The Fibroblast Growth Factor Receptor Acid Box Is Essential for Interactions with N-Cadherin and All of the Major Isoforms of Neural Cell Adhesion Molecule. J Biol Chem 2006; 281:35208-16. [PMID: 17005551 DOI: 10.1074/jbc.m608655200] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interactions between the neural cell adhesion molecules NCAM and N-cadherin with the fibroblast growth factor receptor (FGFR) are important for a number of developmental events and have also been implicated in tumor progression. The factors regulating these interactions are not known. We have used co-immunoprecipitation and co-clustering paradigms to show that both adhesion molecules can interact with the 3Ig IIIC isoform of the FGFR1 in a number of cell types. Interestingly, whereas the interaction can be seen over most of the cell surface, it is not seen at points of cell-cell contact where the adhesion molecules accumulate at stable junctions. We also demonstrate for the first time that all of the major isoforms of NCAM can interact with the FGFR. Using deletion mutagenesis we have found that the adhesion molecule/FGFR interaction can withstand the removal of most of any one of the FGFR immunoglobulin-like domains (D1-D3). In contrast, the FGFR interaction with N-cadherin and NCAM (but not FGF) is absolutely dependant on the presence of the acid box motif that can be found in the linker region between D1 and D2. As this motif can be spliced out of all four FGFRs, it suggests that this is one mechanism that can regulate the interaction of the receptor with different ligand classes.
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Affiliation(s)
- Elena Sanchez-Heras
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom
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87
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Harvey AR, Hu Y, Leaver SG, Mellough CB, Park K, Verhaagen J, Plant GW, Cui Q. Gene therapy and transplantation in CNS repair: The visual system. Prog Retin Eye Res 2006; 25:449-89. [PMID: 16963308 DOI: 10.1016/j.preteyeres.2006.07.002] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Normal visual function in humans is compromised by a range of inherited and acquired degenerative conditions, many of which affect photoreceptors and/or retinal pigment epithelium. As a consequence the majority of experimental gene- and cell-based therapies are aimed at rescuing or replacing these cells. We provide a brief overview of these studies, but the major focus of this review is on the inner retina, in particular how gene therapy and transplantation can improve the viability and regenerative capacity of retinal ganglion cells (RGCs). Such studies are relevant to the development of new treatments for ocular conditions that cause RGC loss or dysfunction, for example glaucoma, diabetes, ischaemia, and various inflammatory and neurodegenerative diseases. However, RGCs and associated central visual pathways also serve as an excellent experimental model of the adult central nervous system (CNS) in which it is possible to study the molecular and cellular mechanisms associated with neuroprotection and axonal regeneration after neurotrauma. In this review we present the current state of knowledge pertaining to RGC responses to injury, neurotrophic and gene therapy strategies aimed at promoting RGC survival, and how best to promote the regeneration of RGC axons after optic nerve or optic tract injury. We also describe transplantation methods being used in attempts to replace lost RGCs or encourage the regrowth of RGC axons back into visual centres in the brain via peripheral nerve bridges. Cooperative approaches including novel combinations of transplantation, gene therapy and pharmacotherapy are discussed. Finally, we consider a number of caveats and future directions, such as problems associated with compensatory sprouting and the reformation of visuotopic maps, the need to develop efficient, regulatable viral vectors, and the need to develop different but sequential strategies that target the cell body and/or the growth cone at appropriate times during the repair process.
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Affiliation(s)
- Alan R Harvey
- School of Anatomy and Human Biology, The University of Western Australia, Crawley, WA 6009, Australia
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88
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Abstract
A range of neurotransmitter systems have been implicated in the pathogenesis of schizophrenia based on the antidopaminergic activities of antipsychotic medications, and chemicals that can induce psychotic-like symptoms, such as ketamine or PCP. Such neurotransmitter systems often mediate their cellular response via G-protein-coupled release of arachidonic acid (AA) via the activation of phospholipases A2 (PLA2s). The interaction of three PLA2s are important for the regulation of the release of AA--phospholipase A2 Group 2 A, phospholipase A2 Group 4A and phospholipase A2 Group 6A. Gene variations of these three key enzymes have been associated with schizophrenia with conflicting results. Preclinical data suggest that the activity of these three enzymes are associated with monoaminergic neurotransmission, and may contribute to the differential efficacy of antipsychotic medications, as well as other biological changes thought to underlie schizophrenia, such as altered neurodevelopment and synaptic remodelling. We review the evidence and discuss the potential roles of these three key enzymes for schizophrenia with particular emphasis on published association studies.
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Affiliation(s)
- M H Law
- Genomic Disorders Research Centre, Melbourne, VI, Australia
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89
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Abstract
Cadherins are expressed on the cell surface as a dimer in the membrane of one cell (cis dimer) that interacts with a cis dimer on an adjacent cell to form an adhesive trans dimer. It is well established that both cis and trans dimers must form for the cadherin to be an effective adhesion protein. In addition to their adhesive activity cadherins also play an important role in modulating cell behavior by regulating cell motility and signal transduction. Whether or not cis or trans dimers are necessary for the nonadhesive functions of cadherins has not been addressed. Here we show that N-cadherin cis dimers are necessary to induce cell motility in epithelial cells and that N-cadherin's ability to modulate the steady state levels of activated small GTPases requires both cis and trans dimers.
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Affiliation(s)
- Young J Kim
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, Nebraska, USA
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90
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Rune GM, Lohse C, Prange-Kiel J, Fester L, Frotscher M. Synaptic plasticity in the hippocampus: effects of estrogen from the gonads or hippocampus? Neurochem Res 2006; 31:145-55. [PMID: 16673174 DOI: 10.1007/s11064-005-9004-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2005] [Indexed: 10/25/2022]
Abstract
Different effects of estrogen on synaptic plasticity have [corrected] been reported. Here, we summarise effects of low, gonad-derived serum estrogen concentrations, of intermediate concentrations, provided by hippocampal cells, and of pharmacological doses of estrogen on synapses and spines and on the expression of synaptic proteins. No effects of low concentrations were found. To study the effects of hippocampus-derived estradiol, we inhibited hippocampal estrogen synthesis by treatment of hippocampal cell cultures with letrozole, an aromatase inhibitor. Alternatively, we used siRNA against Steroidogenic acute regulatory protein (StAR). Spines, synapses, and synaptic proteins were significantly down regulated in response to letrozole and in siRNA-StAR transfected cells. Application of high pharmacological doses of estradiol promoted only synaptophysin expression, a presynaptic protein, but did not increase the number of boutons. Our results point to an essential role of endogenous hippocampal estrogen in hippocampal synaptic plasticity rather than to a direct influence of estrogens derived from peripheral sources, such as the gonads.
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Affiliation(s)
- G M Rune
- Zentrum für Experimentelle Medizin, Institut für Anatomie I: Zelluläre Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Martinistr. 52, D-20246 Hamburg, Germany.
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91
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Hsu JYC, Xu XM. Early profiles of axonal growth and astroglial response after spinal cord hemisection and implantation of Schwann cell-seeded guidance channels in adult rats. J Neurosci Res 2006; 82:472-83. [PMID: 16240391 DOI: 10.1002/jnr.20662] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We previously demonstrated that transplantation of Schwann cell-seeded channels promoted the regrowth of injured axons in the adult spinal cord. It is not clear, however, whether injured axons recapitulate the developmental scenarios to accomplish regeneration. In the present study, we investigated the early events associated with axonal regrowth after spinal cord hemisection at the eighth thoracic level and implantation of a Schwann cell-seeded minichannel in adult rats. Animals were sacrificed at postoperative days (PO) 2, 4, 7, and 14. Anterograde tracing with fluoro-ruby showed that regenerating axons grew into the graft prior to PO2 and reached the distal end of the channel at PO7. These axons expressed both embryonic neural cell adhesion molecule (E-NCAM) and growth associated protein-43 (GAP-43). Although the expression of E-NCAM decreased by PO7, that of GAP-43 remained high throughout the first 2 weeks after implantation. A close relation of vimentin-positive astroglia to the growing axons in the host tissue suggested a contact-mediated role of these cells in axon guidance. Aggregation of glial fibrillary acidic protein (GFAP)-positive astrocytes together with the increased expression of chondroitin sulfate proteoglycans (CSPGs) starting at PO7 appeared to inhibit axonal growth at the host-graft interface. Thus, adult regenerating axons and astroglia do express developmentally related molecules that may facilitate axonal growth into a permissive graft at the early phase of injury and regeneration. These results suggest that molecules and astroglia essential to development are both important in influencing axonal regrowth in the adult spinal cord.
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Affiliation(s)
- Jung-Yu C Hsu
- Department of Anatomy and Neurobiology, Saint Louis University School of Medicine, Missouri, USA
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92
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Iwata M, Shirayama Y, Ishida H, Kawahara R. Hippocampal synapsin I, growth-associated protein-43, and microtubule-associated protein-2 immunoreactivity in learned helplessness rats and antidepressant-treated rats. Neuroscience 2006; 141:1301-13. [PMID: 16814933 DOI: 10.1016/j.neuroscience.2006.04.060] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Revised: 04/04/2006] [Accepted: 04/26/2006] [Indexed: 11/21/2022]
Abstract
Learned helplessness rats are thought to be an animal model of depression. To study the role of synapse plasticity in depression, we examined the effects of learned helplessness and antidepressant treatments on synapsin I (a marker of presynaptic terminals), growth-associated protein-43 (GAP-43; a marker of growth cones), and microtubule-associated protein-2 (MAP-2; a marker of dendrites) in the hippocampus by immunolabeling. (1) Learned helplessness rats showed significant increases in the expression of synapsin I two days after the attainment of learned helplessness, and significant decreases in the protein expression eight days after the achievement of learned helplessness. Subchronic treatment of naïve rats with imipramine or fluvoxamine significantly decreased the expression of synapsin I. (2) Learned helplessness increased the expression of GAP-43 two days and eight days after learned helplessness training. Subchronic treatment of naïve rats with fluvoxamine but not imipramine showed a tendency to decrease the expression of synapsin I. (3) Learned helplessness rats showed increased expression of MAP-2 eight days after the attainment of learned helplessness. Naïve rats subchronically treated with imipramine showed a tendency toward increased expression of MAP-2, but those treated with fluvoxamine did not. These results indicate that the neuroplasticity-related proteins synapsin I, GAP-43, and MAP-2 may play a role in the pathophysiology of depression and the mechanisms of antidepressants.
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Affiliation(s)
- M Iwata
- Department of Neuropsychiatry, Faculty of Medicine, Tottori University, 36-1 Nishi-machi, Yonago, Tottori 683-8504, Japan
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93
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Zhang Y, Bo X, Schoepfer R, Holtmaat AJDG, Verhaagen J, Emson PC, Lieberman AR, Anderson PN. Growth-associated protein GAP-43 and L1 act synergistically to promote regenerative growth of Purkinje cell axons in vivo. Proc Natl Acad Sci U S A 2005; 102:14883-8. [PMID: 16195382 PMCID: PMC1253563 DOI: 10.1073/pnas.0505164102] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Indexed: 01/19/2023] Open
Abstract
Neuronal expression of growth-associated protein 43 (GAP-43) and the cell adhesion molecule L1 has been correlated with CNS axonal growth and regeneration, but it is not known whether expression of these molecules is necessary for axonal regeneration to occur. We have taken advantage of the fact that Purkinje cells do not express GAP-43 or L1 in adult mammals or regenerate axons into peripheral nerve grafts to test the importance of these molecules for axonal regeneration in vivo. Transgenic mice were generated in which Purkinje cells constitutively express L1 or both L1 and GAP-43 under the Purkinje cell-specific L7 promoter, and regeneration of Purkinje cell axons into peripheral nerve grafts implanted into the cerebellum was examined. Purkinje cells expressing GAP-43 or L1 showed minor enhancement of axonal sprouting. Purkinje cells expressing both GAP-43 and L1 showed more extensive axonal sprouting and axonal growth into the proximal portion of the graft. When a predegenerated nerve graft was implanted into double-transgenic mice, penetration of the graft by Purkinje cell axonal sprouts was strongly enhanced, and some axons grew along the entire intracerebral length of the graft (2.5-3.0 mm) and persisted for several months. The results demonstrate that GAP-43 and L1 coexpressed in Purkinje cells can act synergistically to switch these regeneration-incompetent CNS neurons into a regeneration-competent phenotype and show that coexpression of these molecules is a key regulator of the regenerative ability of intrinsic CNS neurons in vivo.
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Affiliation(s)
- Yi Zhang
- Department of Anatomy and Developmental Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom.
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94
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Abstract
Diabetes mellitus impairs peripheral nerve regeneration. Regenerative failure likely exacerbates deficits from polyneuropathy or focal neuropathies in patients who might otherwise exhibit spontaneous improvement. Some focal neuropathies, like carpal tunnel syndrome, are common, yet render ongoing disability because of their delayed recovery. Why diabetic nerves fail to regenerate is an interesting question to consider because several mechanisms likely contribute. In this review, we examine a number of these causes. These causes include microangiopathy or disease of small blood vessels, failure to provide proper metabolic support for repair, defects in the entry and actions of inflammatory cells within the injury milieu, less robust support of axons by their Schwann cells, and lack of a full repertoire of trophic factors. A number of the mechanisms that generate neuropathy in the first place also likely contribute to failed regenerative programs, but how they do so is not clear.
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Affiliation(s)
- James M Kennedy
- Department of Clinical Neurosciences, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada T2N 4N1
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95
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Zakharov VV, Bogdanova MN, Mosevitsky MI. Specific Proteolysis of Neuronal Protein GAP-43 by Calpain: Characterization, Regulation, and Physiological Role. BIOCHEMISTRY (MOSCOW) 2005; 70:897-907. [PMID: 16212546 DOI: 10.1007/s10541-005-0200-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The mechanism of specific proteolysis of the neuronal protein GAP-43 in axonal terminals has been investigated. In synaptic terminals in vivo and in synaptosomes in vitro GAP-43 is cleaved only at the single peptide bond formed by Ser41; this is within the main effector domain of GAP-43. Proteolysis at this site involves the cysteine calcium-dependent neutral protease calpain. The following experimental evidences support this conclusion: 1) calcium-dependent proteolysis of GAP-43 in synaptosomes is insensitive to selective inhibitor of micro-calpain (PD151746), but it is completely blocked by micro- and m-calpain inhibitor PD150606; 2) GAP-43 proteolysis in the calcium ionophore A23187-treated synaptosomes is activated by millimolar concentration of calcium ions; 3) the pattern of fragmentation of purified GAP-43 by m-calpain (but not by micro-calpain) is identical to that observed in synaptic terminals in vivo. GAP-43 phosphorylated at Ser41 by protein kinase C (PKC) is resistant to the cleavage by calpain. In addition, calmodulin binding to GAP-43 decreases the rate of calpain-mediated GAP-43 proteolysis. Our results indicate that m-calpain-mediated GAP-43 proteolysis regulated by PKC and calmodulin is of physiological relevance, particularly in axonal growth cone guidance. We suggest that the function of the N-terminal fragment of GAP-43 (residues 1-40) formed during cleavage by m-calpain consists in activation of neuronal heterotrimeric GTP-binding protein G(o); this results in growth cone turning in response to repulsive signals.
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Affiliation(s)
- V V Zakharov
- Molecular and Radiation Biophysics Division, Petersburg Nuclear Physics Institute, Russian Academy of Sciences, Gatchina, Leningrad Region, 188300, Russia.
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96
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Illing RB, Kraus KS, Meidinger MA. Reconnecting neuronal networks in the auditory brainstem following unilateral deafening. Hear Res 2005; 206:185-99. [PMID: 16081008 DOI: 10.1016/j.heares.2005.01.016] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Accepted: 01/10/2005] [Indexed: 11/27/2022]
Abstract
When we disturbed the auditory input of the adult rat by cochleotomy or noise trauma on one side, several substantial anatomical, cellular, and molecular changes took place in the auditory brainstem. We found that: (1) cochleotomy or severe noise trauma both lead to a considerable increase of immunoreactivity of the growth-associated protein GAP-43 in the ventral cochlear nucleus (VCN) of the affected side; (2) the expression of GAP-43 in VCN is restricted to presynaptic endings and short fiber segments; (3) axon collaterals of the cholinergic medial olivocochlear (MOC) neurons are the path along which GAP-43 reaches VCN; (4) partial cochlear lesions induce the emergence of GAP-43 positive presynaptic endings only in regions tonotopically corresponding to the extent of the lesion; (5) judging from the presence of immature fibers and growth cones in VCN on the deafened side, at least part of the GAP-43 positive presynaptic endings appear to be newly formed neuronal contacts following axonal sprouting while others may be modified pre-existing contacts; and (6) GAP-43 positive synapses are formed only on specific postsynaptic profiles, i.e., glutamatergic, glycinergic and calretinin containing cell bodies, but not GABAergic cell bodies. We conclude that unilateral deafening, be it partial or total, induces complex patterns of reconnecting neurons in the adult auditory brainstem, and we evaluate the possibility that the deafness-induced chain of events is optimized to remedy the loss of a bilaterally balanced activity in the auditory brainstem.
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Affiliation(s)
- Robert-Benjamin Illing
- Neurobiological Research Laboratory, Department of Otorhinolaryngology, University of Freiburg, D-79106 Freiburg, Germany.
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97
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Hsu JYC, Stein SA, Xu XM. Temporal and spatial distribution of growth-associated molecules and astroglial cells in the rat corticospinal tract during development. J Neurosci Res 2005; 80:330-40. [PMID: 15789366 DOI: 10.1002/jnr.20472] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To understand better the role of growth-promoting and -inhibiting molecules in the development of the corticospinal tract (CST), temporospatial expression of embryonic neural cell adhesion molecule (E-NCAM), growth-associated protein-43 (GAP-43), and chondroitin sulfate proteoglycan (CSPG) was studied in developing rats. Transverse sections of the seventh cervical (C7), seventh thoracic (T7), and fourth lumbar (L4) segments were examined at postnatal days (P) 2, 6, 10, 14, and 28. The highest E-NCAM immunoreactivity appeared at the C7 level on P2 and shifted caudally to the T7 on P6 and L4 on P10, which correlated closely with the time course of CST development. The peak expression of GAP-43 emerged at C7 on P2 and shifted to the T7 and L4 levels at a relatively lagging pace compared with that of E-NCAM. Conversely, a transient reduction in CSPG immunoreactivity was found within the CST at the C7 level on P2, T7 level on P6, and L4 level on P10, corresponding well with the arrival of CST-leading axons at these levels. Interestingly, higher levels of CSPG were found to surround the growing CST, suggesting a repulsive environment that channels the growth of CST. Moreover, a transition from immature to mature astrocytes in a rostrocaudal direction during CST development was evidenced by anti-vimentin and anti-glial fibrillary acidic protein (GFAP) immunostaining, suggesting a guidance role of immature astroglia in axonal outgrowth. Our study thus demonstrated dynamic changes of multiple growth-related molecules and astroglial environment that contribute to postnatal development of the CST.
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Affiliation(s)
- Jung-Yu C Hsu
- Department of Anatomy and Neurobiology, Saint Louis University School of Medicine, St. Louis, Missouri, USA
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98
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Abstract
BACKGROUND An important factor in the clinical outcome of cochlear implantation is the age of the patient. Compared to older patients, children with congenital deafness have a better outcome when the implantation is made before the age of 2 years. The cause may lie in the molecular biology of the brain, which changes during postnatal maturation. METHODS Protein probes were obtained from tissue of the rat inferior colliculus at different ages. The probes were analyzed using 2-dimensional SDS electrophoresis. RESULTS The expression of GAP-43, a protein expressed by neurons during axonal outgrowth and synaptogenesis, and the total number of the protein species showed a significant reduction during ontogenesis. This shows that while neurons gradually assume their specific function, they downregulate GAP-43 and the molecular complexity decreases. CONCLUSIONS Due to a lack of neuronal pluripotency at later developmental stages, the flexibility to adapt to the afferent activation provided by a cochlear implant is increasingly limited.
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Affiliation(s)
- C Jung
- Neurobiologisches Forschungslabor der Universitäts-HNO-Klinik Freiburg
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99
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Smith CL, Afroz R, Bassell GJ, Furneaux HM, Perrone-Bizzozero NI, Burry RW. GAP-43 mRNA in growth cones is associated with HuD and ribosomes. ACTA ACUST UNITED AC 2005; 61:222-35. [PMID: 15389607 DOI: 10.1002/neu.20038] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The neuron-specific ELAV/Hu family member, HuD, interacts with and stabilizes GAP-43 mRNA in developing neurons, and leads to increased levels of GAP-43 protein. As GAP-43 protein is enriched in growth cones, it is of interest to determine if HuD and GAP-43 mRNA are associated in developing growth cones. HuD granules in growth cones are found in the central domain that is rich in microtubules and ribosomes, in the peripheral domain with its actin network, and in filopodia. This distribution of HuD granules in growth cones is dependent on actin filaments but not on microtubules. GAP-43 mRNA is localized in granules found in both the central and peripheral domains, but not in filopodia. Ribosomes were extensively colocalized with HuD and GAP-43 mRNA granules in the central domain, consistent with a role in the control of GAP-43 mRNA stability in the growth cone. Together, these results demonstrate that many of the components necessary for GAP-43 mRNA translation/stabilization are present within growth cones.
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Affiliation(s)
- Catherine L Smith
- Department of Neuroscience, College of Medicine and Public Health, The Ohio State University, Columbus, Ohio 43210-1239, USA
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100
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De Moliner KL, Wolfson ML, Perrone Bizzozero N, Adamo AM. Growth-associated protein-43 is degraded via the ubiquitin-proteasome system. J Neurosci Res 2005; 79:652-60. [PMID: 15668958 DOI: 10.1002/jnr.20388] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Growth-associated protein-43 (GAP-43) is a phosphoprotein whose expression in neurons is related to the initial establishment and remodeling of neural connections. GAP-43 gene expression is known to be regulated at both the transcriptional and the postranscriptional levels. However, very little is known about the cellular mechanism involved in the degradation of this protein. Ubiquitin (Ub) is well known for its role in targeting cytoplasmic proteins for degradation by the 26S proteasome. The ubiquitin-proteasome system (UPS) consists of a conserved cascade of three enzymatic components that attach Ub covalently to various substrates and control the degradation of protein involved in several important cellular processes. In this study, we investigated the degradation of GAP-43 in transfected NIH 3T3 cells and neuronal cultures. We found that the proteasome inhibitors, lactacystin and MG132 increased the cellular GAP-43 level, leading to the accumulation of polyubiquitinated forms of this protein in transfected cells and that the Ub-proteasome pathway is also involved in the turnover of this protein in neurons. We conclude based on our findings that GAP-43 is a substrate of the UPS.
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Affiliation(s)
- K L De Moliner
- Departamento de Química Biológica, IQUIFIB, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina
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