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Antonini A, Harris SL, Stryker MP. Neurotrophin NT-4/5 Promotes Structural Changes in Neurons of the Developing Visual Cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.20.572693. [PMID: 38187745 PMCID: PMC10769316 DOI: 10.1101/2023.12.20.572693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Current hypotheses on the mechanisms underlying the development and plasticity of the ocular dominance system through competitive interactions between pathways serving the two eyes strongly suggest the involvement of neurotrophins and their high affinity receptors. In the cat, infusion of the tyrosine kinase B ligand (trkB), neurotrophin-4/5 (NT-4/5), abolishes ocular dominance plasticity that follows monocular deprivation (Gillespie et al., 2000), while tyrosine kinase A and C ligands (trkA and trkC) do not have this effect. One interpretation of this finding is that NT-4/5 causes overgrowth and sprouting of thalamocortical and/or corticocortical terminals, leading to promiscuous neuronal connections which override the experience-dependent fine tuning of connections based on correlated activity. The present study tested whether neurons in cortical regions infused with NT-4/5 showed anatomical changes compatible with this hypothesis. Cats at the peak of the critical period received chronic infusion NT-4/5 into visual cortical areas 17/18 via an osmotic minipump. Visual cortical neurons were labeled in fixed slices using the DiOlistics methods (Gan et al., 2000) and analyzed in confocal microscopy. Infusion of NT-4/5 induced a significant increase of spine-like processes on primary dendrites and a distinctive sprouting of protuberances from neuronal somata in all layers. The increase of neuronal membrane was paralleled by an increase in density of the presynaptic marker synaptophysin in infused areas, suggesting an increase in the numbers of synapses. A contingent of these newly formed synapses may feed into inhibitory circuits, as suggested by an increase of GAD-65 immunostaining in NT-4/5 affected areas. These anatomical changes are consistent with the physiological changes in such animals, suggesting that excess trkB neurotrophin can stimulate the formation of promiscuous connections during the critical period.
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Affiliation(s)
- Antonella Antonini
- Kavli Center for Fundamental Neuroscience, Department of Physiology, University of California, San Francisco, California 94158
| | - Sheri L Harris
- Kavli Center for Fundamental Neuroscience, Department of Physiology, University of California, San Francisco, California 94158
| | - Michael P Stryker
- Kavli Center for Fundamental Neuroscience, Department of Physiology, University of California, San Francisco, California 94158
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Chiba A, Soma K, Watanabe K, Nagashima H, Sato N. Development of fin-innervating motor neurons after peripheral target removal in medaka fish. Dev Neurobiol 2020; 81:110-122. [PMID: 33277778 DOI: 10.1002/dneu.22799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 10/20/2020] [Accepted: 11/27/2020] [Indexed: 11/12/2022]
Abstract
Peripheral targets regulate the development and survival of the nerve centers that serve them, because the elimination of the target normally results in massive death of the developing neurons that innervate it. This widely accepted theory appears to be well supported by developing limbs and their innervation in tetrapods, but it is unclear whether this concept applies to primitive vertebrates that have paired appendages. In this study, we examined the development of spinal motor neurons following pectoral fin bud removal (FBR) in medaka fish. After FBR, motor axons initially extended to the plexus region in a morphologically normal pattern. During the period of fin innervation, motor axons in the FBR-medaka failed to form the normal brachial plexus and elongated ventrally toward the abdominal region. In the ventral horn that would normally innervate the pectoral fin, however, neurons did not undergo cell death following FBR. There were no differences in the numbers of axons in the ventral roots between the FBR and control sides. Motor neuron markers, RALDH2 and FOXP1, that are expressed in limb-innervating motor neurons in the lateral motor column in tetrapods, were also expressed in the ventral horns of both the control and FBR sides in medaka fish. These results suggest that, although both tetrapod and medaka motor neurons share the same molecular characteristics for innervating paired appendages, the fates of neurons differ following the removal of their peripheral target. Therefore, the relationship between the peripheral target and its nerve center may be altered among vertebrates.
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Affiliation(s)
- Akina Chiba
- Division of Gross Anatomy and Morphogenesis, Department of Regenerative and Transplant Medicine, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Kenichi Soma
- Division of Gross Anatomy and Morphogenesis, Department of Regenerative and Transplant Medicine, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Keisuke Watanabe
- Division of Gross Anatomy and Morphogenesis, Department of Regenerative and Transplant Medicine, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Hiroshi Nagashima
- Division of Gross Anatomy and Morphogenesis, Department of Regenerative and Transplant Medicine, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Noboru Sato
- Division of Gross Anatomy and Morphogenesis, Department of Regenerative and Transplant Medicine, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
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Hong SJ, Cho J, Boo CG, Youn MY, Pan JH, Kim JK, Shin EC. Inhalation of Patchouli ( Pogostemon Cablin Benth.) Essential Oil Improved Metabolic Parameters in Obesity-Induced Sprague Dawley Rats. Nutrients 2020; 12:E2077. [PMID: 32668680 PMCID: PMC7400805 DOI: 10.3390/nu12072077] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 12/22/2022] Open
Abstract
This study investigated effects of patchouli essential oil (PEO) inhalation on metabolic parameters. First, to characterize aromatic compounds in PEO, solid-phase microextraction-gas chromatography/mass spectrometric detection was employed in which 19 aromatic compounds were identified. In GC-olfactometry analysis, linalool, α-patchoulene, and β-patchoulene were found to be the constituents exhibiting the highest similarity to the aromatic compounds in patchouli. In an animal experiment using Sprague Darley rats, groups with PEO inhalation had a reduced food intake compared to the control group. Additionally, body weight was lower in the obesity-induced animal model exposed to PEO inhalation than the group without PEO. However, we found no significant difference in organ weights between groups. In our serum analysis, high-density lipoprotein cholesterol was significantly higher in the PEO inhalation groups, while low-density lipoprotein cholesterol content was highest in the positive control group, suggesting that inhalation of the aromatic compounds present in patchouli may improve cholesterol profile. In addition, leptin levels were reduced in the groups treated with PEO inhalation, which explains the differences in food intake and body weight gains. Last, animal groups exposed to PEO inhalation showed a relatively lower systolic blood pressure which suggests that inhalation of PEO (or aromatic compounds therein) may assist in regulating blood pressure. Collectively, our data demonstrate that the inhalation of PEO influenced certain markers related to metabolic diseases, hence provide basic data for future research as to preventive/therapeutic applications of PEO as well as their aromatic constituents.
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Affiliation(s)
- Seong Jun Hong
- Department of Food Science, Gyeongnam National University of Science and Technology, Jinju 52725, Korea; (S.J.H.); (J.C.); (C.G.B.); (M.Y.Y.)
| | - Jinju Cho
- Department of Food Science, Gyeongnam National University of Science and Technology, Jinju 52725, Korea; (S.J.H.); (J.C.); (C.G.B.); (M.Y.Y.)
| | - Chang Guk Boo
- Department of Food Science, Gyeongnam National University of Science and Technology, Jinju 52725, Korea; (S.J.H.); (J.C.); (C.G.B.); (M.Y.Y.)
| | - Moon Yeon Youn
- Department of Food Science, Gyeongnam National University of Science and Technology, Jinju 52725, Korea; (S.J.H.); (J.C.); (C.G.B.); (M.Y.Y.)
| | - Jeong Hoon Pan
- Department of Behavioral Health and Nutrition, University of Delaware, Newark, DE 19716, USA; (J.H.P.); (J.K.K.)
| | - Jae Kyeom Kim
- Department of Behavioral Health and Nutrition, University of Delaware, Newark, DE 19716, USA; (J.H.P.); (J.K.K.)
| | - Eui-Cheol Shin
- Department of Food Science, Gyeongnam National University of Science and Technology, Jinju 52725, Korea; (S.J.H.); (J.C.); (C.G.B.); (M.Y.Y.)
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Terenzio M, Schiavo G, Fainzilber M. Compartmentalized Signaling in Neurons: From Cell Biology to Neuroscience. Neuron 2017; 96:667-679. [PMID: 29096079 DOI: 10.1016/j.neuron.2017.10.015] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 09/27/2017] [Accepted: 10/09/2017] [Indexed: 12/18/2022]
Abstract
Neurons are the largest known cells, with complex and highly polarized morphologies. As such, neuronal signaling is highly compartmentalized, requiring sophisticated transfer mechanisms to convey and integrate information within and between sub-neuronal compartments. Here, we survey different modes of compartmentalized signaling in neurons, highlighting examples wherein the fundamental cell biological processes of protein synthesis and degradation, membrane trafficking, and organelle transport are employed to enable the encoding and integration of information, locally and globally within a neuron. Comparisons to other cell types indicate that neurons accentuate widely shared mechanisms, providing invaluable models for the compartmentalization and transfer mechanisms required and used by most eukaryotic cells.
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Affiliation(s)
- Marco Terenzio
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Giampietro Schiavo
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London WC1N 3BG, UK; Discoveries Centre for Regenerative and Precision Medicine at UCL, London WC1N 3BG, UK; UK Dementia Research Institute at UCL, London WC1E 6BT, UK
| | - Mike Fainzilber
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
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Schmieg N, Menendez G, Schiavo G, Terenzio M. Signalling endosomes in axonal transport: Travel updates on the molecular highway. Semin Cell Dev Biol 2014; 27:32-43. [DOI: 10.1016/j.semcdb.2013.10.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Revised: 10/17/2013] [Accepted: 10/19/2013] [Indexed: 01/11/2023]
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Abstract
Neurotrophins are a family of target-derived growth factors that support survival, development, and maintenance of innervating neurons. Owing to the unique architecture of neurons, neurotrophins that act locally on the axonal terminals must convey their signals across the entire axon for subsequent regulation of gene transcription in the cell nucleus. This long-distance retrograde signaling, a motor-driven process that can take hours or days, has been a subject of intense interest. In the last decade, live-cell imaging with high sensitivity has significantly increased our capability to track the transport of neurotrophins, their receptors, and subsequent signals in real time. This review summarizes recent research progress in understanding neurotrophin-receptor interactions at the axonal terminal and their transport dynamics along the axon. We emphasize high-resolution studies at the single-molecule level and also discuss recent technical advances in the field.
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Zigmond RE. gp130 cytokines are positive signals triggering changes in gene expression and axon outgrowth in peripheral neurons following injury. Front Mol Neurosci 2012; 4:62. [PMID: 22319466 PMCID: PMC3262188 DOI: 10.3389/fnmol.2011.00062] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 12/28/2011] [Indexed: 01/24/2023] Open
Abstract
Adult peripheral neurons, in contrast to adult central neurons, are capable of regeneration after axonal damage. Much attention has focused on the changes that accompany this regeneration in two places, the distal nerve segment (where phagocytosis of axonal debris, changes in the surface properties of Schwann cells, and induction of growth factors and cytokines occur) and the neuronal cell body (where dramatic changes in cell morphology and gene expression occur). The changes in the axotomized cell body are often referred to as the "cell body response." The focus of the current review is a family of cytokines, the glycoprotein 130 (gp130) cytokines, which produce their actions through a common gp130 signaling receptor and which function as injury signals for axotomized peripheral neurons, triggering changes in gene expression and in neurite outgrowth. These cytokines play important roles in the responses of sympathetic, sensory, and motor neurons to injury. The best studied of these cytokines in this context are leukemia inhibitory factor (LIF) and interleukin (IL)-6, but experiments with conditional gp130 knockout animals suggest that other members of this family, not yet determined, are also involved. The primary gp130 signaling pathway shown to be involved is the activation of Janus kinase (JAK) and the transcription factors Signal Transducers and Activators of Transcription (STAT), though other downstream pathways such as mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) may also play a role. gp130 signaling may involve paracrine, retrograde, and autocrine actions of these cytokines. Recent studies suggest that manipulation of this cytokine system can also stimulate regeneration by injured central neurons.
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Affiliation(s)
- Richard E. Zigmond
- Department of Neurosciences, Case Western Reserve University, ClevelandOH, USA
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Kanter M. Protective effects of thymoquinone on the neuronal injury in frontal cortex after chronic toluene exposure. J Mol Histol 2010; 42:39-46. [DOI: 10.1007/s10735-010-9305-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Accepted: 11/09/2010] [Indexed: 10/18/2022]
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Protective Effects of Nigella sativa on the Neuronal Injury in Frontal Cortex and Brain Stem After Chronic Toluene Exposure. Neurochem Res 2008; 33:2241-9. [DOI: 10.1007/s11064-008-9702-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Accepted: 04/03/2008] [Indexed: 10/22/2022]
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Bähr M, Lingor P. Brain repair: Experimental treatment strategies, neuroprotective and repair strategies in the lesioned adult CNS. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 557:148-63. [PMID: 16955709 DOI: 10.1007/0-387-30128-3_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Mathias Bähr
- Department of Neurology, University of Göttingen, Germany
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11
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Nikolaou KE, Malamitsi-Puchner A, Boutsikou T, Economou E, Boutsikou M, Puchner KP, Baka S, Hassiakos D. The Varying Patterns of Neurotrophin Changes in the Perinatal Period. Ann N Y Acad Sci 2006; 1092:426-33. [PMID: 17308169 DOI: 10.1196/annals.1365.041] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Neurotrophins (NTs), nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), NT-3, and NT-4 are of major importance in prenatal and postnatal brain development, due to their neuroprotective action. Developmental changes alter the neuronal responsiveness to certain NTs, which subsequently are variously expressed, to properly balance their action. The following study aimed at examining the pattern of perinatal changes of the four NTs--NGF, BDNF, NT-3, and NT-4 in 30 appropriate for gestational age (AGA) full-term fetuses and neonates by determining their circulating levels at characteristic time points. This study show a gradual decrease of circulating levels of the NTs, NT-3 and NT-4 from umbilical cord (UC) to neonates day 4 (N4), while circulating levels of NGF and BDNF present the opposite pattern: an increase from UC to N4. These patterns of perinatal changes differ according to their impact on the process of neuronal development and their reaction to perinatal stress. NT3 and NT4 have been documented to act at early stages of neuronal development and to decrease after hypoxia-ischemia, while NGF and BDNF to increase. Further studies should investigate these patterns in premature or full-term infants, presenting various pathological conditions in the perinatal period.
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Affiliation(s)
- K E Nikolaou
- Neonatal Division, Second Department of Obstetrics and Gynecology, University of Athens, 19, Soultani Street, GR-10682 Athens, Greece
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12
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Sophou S, Dori I, Antonopoulos J, Parnavelas JG, Dinopoulos A. Apoptosis in the rat basal forebrain during development and following lesions of connections. Eur J Neurosci 2006; 24:573-85. [PMID: 16903859 DOI: 10.1111/j.1460-9568.2006.04929.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Evidence suggests that neurotrophins are essential for the survival and phenotypic maintenance of cholinergic basal forebrain (BF) neurons. We evaluated the pattern of programmed cell death in the BF of the rat during development and after ablations of the cerebral cortex, a major target area and source of neurotrophins for BF neurons. We identified dying cells using the TUNEL (terminal deoxynucleotidyl-transferase-mediated dUTP-biotin nick end labelling) method and confirmed their apoptotic morphology with electron microscopy. Moreover, we demonstrated the expression of the apoptotic marker active caspase-3 in cells with features of apoptosis. TUNEL(+) cells were present in the developing BF during the first two postnatal weeks. Their frequency peaked at postnatal day (P)1 and at P5. TUNEL used in conjunction with immunofluorescence for neuronal nuclear protein (NeuN) showed that, at both peak stages, the majority of apoptotic cells were neurons. Extensive lesions of the cerebral cortex at different ages (P0, P7 and P14) did not induce significant changes in the frequency of apoptotic BF neurons. However, they resulted in alterations in the morphological phenotype of choline acetyltransferase (ChAT)-immunoreactive neurons in the BF, and a reduction in their number which was inversely proportional to the age at which the lesions were performed. We suggest that: (i) apoptosis is temporally coordinated with the morphological and neurochemical differentiation of BF neurons and the establishment of connections with their target areas; and (ii) cortical ablations do not affect the survival of BF neurons, but they influence the phenotype of cholinergic BF neurons.
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Affiliation(s)
- Stavroula Sophou
- Department of Anatomy and Histology, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
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Abstract
A dictum long-held has stated that the adult mammalian brain and spinal cord are not capable of regeneration after injury. Recent discoveries have, however, challenged this dogma. In particular, a more complete understanding of developmental neurobiology has provided an insight into possible ways in which neuronal regeneration in the central nervous system may be encouraged. Knowledge of the role of neurotrophic factors has provided one set of strategies which may be useful in enhancing CNS regeneration. These factors can now even be delivered to injury sites by transplantation of genetically modified cells. Another strategy showing great promise is the discovery and isolation of neural stem cells from adult CNS tissue. It may become possible to grow such cells in the laboratory and use these to replace injured or dead neurons. The biological and cellular basis of neural injury is of special importance to neurosurgery, particularly as therapeutic options to treat a variety of CNS diseases becomes greater.
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Affiliation(s)
- Ross D Gurgo
- Department of Neurosurgery, Princess Alexandra Hospital, Brisbane, Australia.
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Bennet MR, Gibson WG, Lemon G. Neuronal cell death, nerve growth factor and neurotrophic models: 50 years on. Auton Neurosci 2002; 95:1-23. [PMID: 11871773 DOI: 10.1016/s1566-0702(01)00358-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Viktor Hamburger has just died at the age of 100. It is 50 years since he and Rita Levi-Montalcini laid the foundations for the study of naturally occurring cell death and of neurotrophic factors in the nervous system. In a period of less than 10 years, from 1949 to 1958, Hamburger and Levi-Montalcini made the following seminal discoveries: that neuron cell death occurs in dorsal root ganglia, sympathetic ganglia and the cervical column of motoneurons; that the predictions arising from this observation, namely that survival is dependent on the supply of a trophic factor, could be substantiated by studying the effects of a sarcoma on the proliferation of ganglionic processes both in vivo and in vitro; and that the proliferation of these processes could be used as an assay system to isolate the factor. This work provides a short review mostly of the early history of this subject in the context of the Hamburger/Levi-Montalcini paradigm. This acts as an introduction to a consideration of models that have been proposed to account for how the different sources of growth factors provide for the survival of neurons during development. It is suggested that what has been called the 'social-control' model provides the most parsimonious quantitative description of the contribution of trophic factors to neuronal survival, a concept for which we are in debt to Viktor Hamburger and Rita Levi-Montalcini.
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Affiliation(s)
- M R Bennet
- Department of Physiology, Institute for Biomedical Research, University of Sydney, New South Wales, Australia.
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Oppenheim RW. Viktor Hamburger (1900-2001). Journey of a neuroembryologist to the end of the millennium and beyond. Neuron 2001; 31:179-90. [PMID: 11502251 DOI: 10.1016/s0896-6273(01)00366-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- R W Oppenheim
- Department of Neurobiology and Anatomy, The Neuroscience Program, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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von Bartheld CS, Wang X, Butowt R. Anterograde axonal transport, transcytosis, and recycling of neurotrophic factors: the concept of trophic currencies in neural networks. Mol Neurobiol 2001; 24:1-28. [PMID: 11831547 DOI: 10.1385/mn:24:1-3:001] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Traditional views of neurotrophic factor biology held that trophic factors are released from target cells, retrogradely transported along their axons, and rapidly degraded upon arrival in cell bodies. Increasing evidence indicates that several trophic factors such as brain-derived neurotrophic factor (BDNF), fibroblast growth factor (FGF-2), glial cell-line derived neurotrophic factor (GDNF), insulin-like growth factor (IGF-I), and neurotrophin-3 (NT-3), can move anterogradely along axons. They can escape the degradative pathway upon internalization and are recycled for future uses. Internalized ligands can move through intermediary cells by transcytosis, presumably by endocytosis via endosomes to the Golgi system, by trafficking of the factor to dendrites or by sorting into anterograde axonal transport with subsequent release from axon terminals and uptake by second- or third-order target neurons. Such data suggest the existence of multiple "trophic currencies," which may be used over several steps in neural networks to enable nurturing relationships between connected neurons or glial cells, not unlike currency exchanges between trading partners in the world economy. Functions of multistep transfer of trophic material through neural networks may include regulation of neuronal survival, differentiation of phenotypes and dendritic morphology, synapse plasticity, as well as excitatory neurotransmission. The molecular mechanisms of sorting, trafficking, and release of trophic factors from distinct neuronal compartments are important for an understanding of neurotrophism, but they present challenging tasks owing to the low levels of the endogenous factors.
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Affiliation(s)
- C S von Bartheld
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno 89557, USA.
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Cardiotrophin-1, a muscle-derived cytokine, is required for the survival of subpopulations of developing motoneurons. J Neurosci 2001. [PMID: 11160399 DOI: 10.1523/jneurosci.21-04-01283.2001] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Developing motoneurons require trophic support from their target, the skeletal muscle. Despite a large number of neurotrophic molecules with survival-promoting activity for isolated embryonic motoneurons, those factors that are required for motoneuron survival during development are still not known. Cytokines of the ciliary neurotrophic factor (CNTF)-leukemia inhibitory factor (LIF) family have been shown to play a role in motoneuron (MN) survival. Importantly, in mice lacking the LIFRbeta or the CNTFRalpha there is a significant loss of MNs during embryonic development. Because genetic deletion of either (or both) CNTF or LIF fails, by contrast, to perturb MN survival before birth, it was concluded that another ligand exists that is functionally inactivated in the receptor deleted mice, resulting in MN loss during development. One possible candidate for this ligand is the CNTF-LIF family member cardiotrophin-1 (CT-1). CT-1 is highly expressed in embryonic skeletal muscle, secreted by myotubes, and promotes the survival of cultured embryonic mouse and rat MNs. Here we show that ct-1 deficiency causes increased motoneuron cell death in spinal cord and brainstem nuclei of mice during a period between embryonic day 14 and the first postnatal week. Interestingly, no further loss was detectable during the subsequent postnatal period, and nerve lesion in young adult ct-1-deficient mice did not result in significant additional loss of motoneurons, as had been previously observed in mice lacking both CNTF and LIF. CT-1 is the first bona fide muscle-derived neurotrophic factor to be identified that is required for the survival of subgroups of developing motoneurons.
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Von Bartheld CS, Johnson JE. Target-derived BDNF (brain-derived neurotrophic factor) is essential for the survival of developing neurons in the isthmo-optic nucleus. J Comp Neurol 2001; 433:550-64. [PMID: 11304717 DOI: 10.1002/cne.1159] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Neurons in the peripheral nervous system depend on single neurotrophic factors, whereas those in the brain are thought to utilize many different trophic factors. This study examined whether some neurons in the brain critically depend on a single trophic factor during development. Neurons in the isthmo-optic nucleus (ION) of chick embryos respond to exogenous brain-derived neurotrophic factor (BDNF). Relatively high concentrations of endogenous BDNF were present in the ION of 14-18-day-old chick embryos. ION target cells in the retina were immunolabeled for BDNF but showed surprisingly low levels of BDNF mRNA. These data suggest that ION target cells derive some BDNF from other retinal sources. No BDNF mRNA was detected in the ION itself. ION neurons had a very efficient retrograde transport system for BDNF and exogenous BDNF arrived in the ION intact. When the ION was deprived of endogenous trkB ligands by injection of trkB fusion proteins in the eye, cell death of ION neurons was enhanced, and this effect was mimicked by BDNF-specific blocking antibodies in the eye. TrkB fusion proteins in the retina induced cell death of ION neurons prior to visible effects on ION target cells in the retina. Immunolabel for endogenous BDNF was sparse in pyknotic ION neurons, suggesting that ION neurons with low BDNF content were eliminated by apoptosis. These data show that BDNF is an essential target-derived trophic factor for developing ION neurons and thereby validate the neurotrophic hypothesis for at least one neuronal population in the brain.
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Affiliation(s)
- C S Von Bartheld
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada 89557, USA.
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Padilla S. Biochemical approaches to studying neurotoxicity. CURRENT PROTOCOLS IN TOXICOLOGY 2001; Chapter 12:Unit12.1. [PMID: 23045030 DOI: 10.1002/0471140856.tx1201s03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This overview provides an introduction to biochemical analysis of toxicant effects on the nervous system. It includes a brief discussion of the salient features of the nervous system and a review of the various approaches used to detect and identify neurotoxicants and their modes of action.
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Affiliation(s)
- S Padilla
- U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
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Oppenheim RW, Lauder JM. Viktor Hamburger at 100: eight decades of neuroembryological research, 1920--2000. Int J Dev Neurosci 2001; 19:117-22. [PMID: 11334020 DOI: 10.1016/s0736-5748(00)00072-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- R W Oppenheim
- Department of Neurobiology and Anatomy, Wake Forest University Medical School, Winston-Salem, NC 2717-1010, USA.
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21
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Abstract
Topographic refinement of synaptic connections within the developing visual system involves a variety of molecules which interact with impulse activity in order to produce the precise retinotopic maps found in the adult brain. Nitric oxide (NO) has been implicated in this process, as have various growth factors. Within the subcortical visual system, we have recently shown that nitric oxide contributes to pathway refinement in the superior colliculus (SC). Long-term potentiation (LTP) and long-term depression (LTD) are also expressed in SC during the time that this pathway undergoes refinement. The role of NO has been demonstrated by showing that refinement of ipsilateral fibers in the retinocollicular pathway is significantly delayed in gene knockout mice in which both the endothelial and neuronal isoforms of nitric oxide synthase (NOS) have been disrupted. The effect also depends upon Ca(2+) channels because refinement of both the ipsilateral retinocollicular and retinogeniculate pathways is disrupted in genetic mutants in which the beta3 subunit of the Ca(2+) channel has been deleted. LTD may also be involved in this process, because the time course of its expression correlates with that of pathway refinement and LTD magnitude is depressed by nitrendipine, an L-type Ca(2+) channel blocker. LTP is also expressed during early postnatal development in the LGN and SC and may contribute to synaptic stabilization. The role of neurotrophins in pathway refinement in the visual system is also reviewed.
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Affiliation(s)
- R R Mize
- Department of Cell Biology and Anatomy and The Neuroscience Center, Louisiana State University Health Sciences Center, 70112, New Orleans, LA, USA.
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22
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Harrison SM, Jones ME, Uecker S, Albers KM, Kudrycki KE, Davis BM. Levels of nerve growth factor and neurotrophin-3 are affected differentially by the presence of p75 in sympathetic neurons in vivo. J Comp Neurol 2000; 424:99-110. [PMID: 10888742 DOI: 10.1002/1096-9861(20000814)424:1<99::aid-cne8>3.0.co;2-j] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The development and survival of sympathetic neurons is critically dependent on the related neurotrophic factors nerve growth factor (NGF) and neurotrophin-3 (NT3), the actions of which must be executed appropriately despite spatial and temporal overlaps in their activities. The tyrosine receptor kinases, trkA and trkC, are the cognate receptors for NGF and NT3, respectively. The p75 neurotrophin receptor has been implicated in neurotrophin binding and signaling for both NGF and NT3. In this study, the authors used mice that overexpressed NGF (NGF-OE) or NT3 (NT3-OE) in skin and mice that lacked p75 (p75(-/-)) to understand the dynamics of sympathetic neuron response to each neurotrophin and to address the role of p75. NGF and NT3 were measured in sympathetic ganglia and skin (a major target of sympathetic neurons) by using the enzyme-linked immunosorbent assay (ELISA) technique. A three- to four-fold increase in skin NT3 was seen in both NT3-OE and p75(-/-) mice. Moreover, both mouse lines exhibited a three-fold increase in ganglionic NT3. However, the increase in ganglionic NT3 was accompanied by a decrease in ganglionic NGF in p75(-/-) mice but not in NT3-OE mice. This indicated that p75 plays an important role in determining the level of NGF within sympathetic neurons. In NGF-OE mice, the overexpression of NGF was correlated with increased ganglionic NGF and increased ganglionic expression of p75 mRNA. In addition, in NGF-OE mice, ganglionic trkC expression was decreased, as was the amount of NT3 present within sympathetic ganglia. These results indicate that the level of p75 is integral in determining the level of sympathetic NGF and that NGF competes with NT3 by increasing the expression of p75 and decreasing the expression of trkC.
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MESH Headings
- Animals
- Cell Count
- Ganglia, Sympathetic/cytology
- Ganglia, Sympathetic/metabolism
- Mice
- Mice, Knockout/genetics
- Mice, Transgenic/genetics
- Nerve Growth Factor/genetics
- Nerve Growth Factor/metabolism
- Neurons/cytology
- Neurons/metabolism
- Neurotrophin 3/genetics
- Neurotrophin 3/metabolism
- RNA, Messenger/metabolism
- Receptor, Nerve Growth Factor/genetics
- Receptor, Nerve Growth Factor/metabolism
- Receptor, trkA/genetics
- Receptor, trkC/genetics
- Receptors, Nerve Growth Factor/metabolism
- Skin/metabolism
- Tissue Distribution
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Affiliation(s)
- S M Harrison
- Department of Anatomy and Neurobiology, University of Kentucky College of Medicine, Lexington, Kentucky 40536, USA
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23
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Kramer BM, Van der Zee CE, Hagg T. P75 nerve growth factor receptor is important for retrograde transport of neurotrophins in adult cholinergic basal forebrain neurons. Neuroscience 2000; 94:1163-72. [PMID: 10625055 DOI: 10.1016/s0306-4522(99)00387-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The role of the p75 nerve growth factor receptor in the retrograde transport of neurotrophins in the adult CNS was investigated by comparing the transport of 125I-labeled neurotrophins by normal and p75 nerve growth factor receptor-deficient cholinergic septohippocampal neurons. In control mice, nerve growth factor was selectively transported from the hippocampal formation to the cholinergic neurons in the septum. Nerve growth factor labeling was found in three to four times as many septal cholinergic neuronal cell bodies than labeling for neurotrophin-3 or neurotrophin-4/5, and transported brain-derived neurotrophic factor was barely detectable. Cells were considered as labeled when the number of grains per cell exceeded five times background. In p75 nerve growth factor receptor-deficient mice, the number of cholinergic neurons labeled with each of the neurotrophins was reduced by 85-95%. Retrograde labeling of septohippocampal neurons with Fluorogold was not obviously reduced in p75 nerve growth factor receptor-deficient mice, suggesting that general transport mechanisms were not impaired. Despite the reduced neurotrophin transport, cholinergic neurons of p75 nerve growth factor receptor-deficient mice were larger than controls and had an apparently normal density of immunostaining for choline acetyltransferase. Since nerve growth factor is reportedly involved in size regulation and choline acetyltransferase expression, this raises the possibility that the retrograde transport itself is not essential for these events. Thus, p75 nerve growth factor receptor plays an important, although not exclusive, role in the transport of neurotrophins by cholinergic basal forebrain neurons, and retrograde transport of nerve growth factor may not be needed for regulating certain cellular processes.
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Affiliation(s)
- B M Kramer
- Department of Anatomy and Neurobiology, Dalhousie University, Halifax, Nova Scotia, Canada
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24
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Expression of neurotrophin-3 (NT-3) and anterograde axonal transport of endogenous NT-3 by retinal ganglion cells in chick embryos. J Neurosci 2000. [PMID: 10632603 DOI: 10.1523/jneurosci.20-02-00736.2000] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Anterograde axonal transport of neurotrophins has been demonstrated recently, but to date such transport has only been shown for brain-derived neurotrophic factor and no other endogenous neurotrophin. Endogenous neurotrophin-3 (NT-3) protein is present in the ganglion cell layer of the chicken retina, as well as the superficial layers of the optic tectum. NT-3 immunolabel in these tectal layers is largely reduced or abolished after treatment of the eye with colchicine or monensin, demonstrating that endogenous NT-3 is transported to the optic tectum by retinal ganglion cells (RGCs). Reverse transcription-PCR analysis of RGCs purified to 100% shows that RGCs, but not tectal cells, express NT-3 mRNA. Blockade of the intercellular transfer of NT-3 within the retina does not reduce the anterograde transport of endogenous NT-3 to the tectum, indicating that a major fraction of the anterogradely transported NT-3 is produced by RGCs rather than taken up from other retinal cells. Immunolabel for the neurotrophin receptor p75, but not trkB or trkC, in the superficial tectum coincides with the NT-3 label. The p75 label in the neuropil of superficial tectal layers is largely reduced or eliminated by injection of monensin in the eye, indicating that p75 protein is exported along RGC axons to the retinotectal terminals and may act as a neurotrophin carrier. These results show that NT-3 is produced by RGCs and that some of this NT-3 is transported anterogradely along the axons to the superficial layers of the tectum, possibly to regulate the survival, synapse formation, or dendritic growth of tectal neurons.
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25
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Abstract
Membrane dynamics within the chick ciliary neuronal growth cone were investigated by using the membrane-impermeant dye FM1-43. A depolarization-evoked endocytosis was observed that shared many properties with the synaptic vesicle recycling previously described at the presynaptic terminal. In addition, in the absence of depolarization a basal level of constitutive endocytotic activity was observed at approximately 30% of the rate of evoked endocytosis. This constitutive endocytosis accounted for large amounts of membrane retrieval: the equivalent of the entire growth cone surface area could be internalized within a 30 min period. Endosomes generated via constitutive and evoked processes were highly mobile and could move considerable distances both within the growth cone and out to the neurite. In addition to their different requirements for formation, evoked and constitutive endosomes displayed a significant difference in release properties. After a subsequent depolarization of labeled growth cones, evoked endosomes were released although constitutive endosomes were not released. Furthermore, treatment with latrotoxin released evoked endosomes, but not constitutive endosomes. Although the properties of evoked endosomes are highly reminiscent of synaptic vesicles, constitutive endosomes appear to be a separate pool resulting from a distinct and highly active process within the neuronal growth cone.
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26
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Bergman E, Kullberg S, Ming Y, Ulfhake B. Upregulation of GFRalpha-1 and c-ret in primary sensory neurons and spinal motoneurons of aged rats. J Neurosci Res 1999; 57:153-65. [PMID: 10398293 DOI: 10.1002/(sici)1097-4547(19990715)57:2<153::aid-jnr1>3.0.co;2-a] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Aging is associated with a decline in neuromuscular and somatosensory functions. Senile muscle atrophy, considered to be of neurogenic origin, is prevalent, and sensory thresholds increase with age. However, the loss of motoneurons and primary sensory neurons is small, while sensory and motor innervation appears disturbed due to aging-related axon lesions. One mechanism which may play a role in this process is altered trophin signaling. We here report that the glial cell line-derived neurotrophic factor (GDNF) receptor GFRalpha-1 mRNA and GFRalpha-1 protein-like immunoreactivity are upregulated in spinal motoneurons, and in dorsal root ganglion neurons of 30-month-old rats. The established signaling mechanism for the GDNF/GFRalpha-1 complex is through binding to the tyrosine kinase receptor encoded by the c-ret proto-oncogene, and we also show here that c-ret mRNA is upregulated in both motoneurons and primary sensory neurons of aged rats. The findings reported here, combined with evidence presented in other studies of changes in p75(NTR) and trk receptor expressions in aging primary sensory neurons and motoneurons, point at marked alterations in trophin signaling in senescence.
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Affiliation(s)
- E Bergman
- Chemical Neurotransmission Unit, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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27
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Johnson H, Hökfelt T, Ulfhake B. Expression of p75(NTR), trkB and trkC in nonmanipulated and axotomized motoneurons of aged rats. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1999; 69:21-34. [PMID: 10350634 DOI: 10.1016/s0169-328x(99)00068-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Several lines of evidence indicate that adult neurons remain dependent on neurotrophins and that changes in tissue expression of neurotrophins and/or their receptors may play a role in senile neurodegeneration. We have studied the expression of p75NTR, trkB and trkC, respectively, in lumbar motoneurons of young adult (2-3 months) and aged (30 months) rats subjected to sciatic transection using in situ hybridization and immunohistochemistry. Nonmanipulated age-matched animals were processed in parallel. In nonmanipulated aged rats, high levels of p75NTR could be seen in a number of motoneurons (10-15%), while in young adult animals no p75NTR could be detected. Seven days following sciatic axotomy, a conspicuous ipsilateral upregulation p75NTR was observed in young adult rats. Also in aged rats there was a marked ipsilateral increase in number of p75NTR expressing neurons ( approximately 100%). In comparison to young adult rats, aged rats showed a decreased expression of both trkB (5/6 animals) and trkC (6/6 animals). Furthermore, in response to sciatic transection, 3 out of 5 aged rats did not show an increased expression of trkB. In aged rats, axotomy did not induce any significant change in trkC expression. In the young adult rats, we recorded a side-to-side effect with lower values ipsilaterally, however, it cannot be excluded that this difference was caused by an upregulation in the contralateral motoneurons. Oligonucleotide probes against BDNF and NT3 mRNA showed only very few faintly positive neurons in both age groups. Our results indicate that the pattern of regulatory changes of NT receptors in response to axotomy is different in aged and young adult rats. The lack of covariation between p75NTR and trkB and trkC regulation in aged rats indicates a changed role for p75NTR in senescent motoneurons.
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Affiliation(s)
- H Johnson
- Department of Neuroscience, Karolinska Institutet, Division of Neuroanatomy and Neuronal Plasticity, S-171 77, Stockholm, Sweden.
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28
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Abstract
Despite considerable evidence that neuronal activity influences the organization and function of circuits in the developing and adult brain, the molecular signals that translate activity into structural and functional changes in connections remain largely obscure. This review discusses the evidence implicating neurotrophins as molecular mediators of synaptic and morphological plasticity. Neurotrophins are attractive candidates for these roles because they and their receptors are expressed in areas of the brain that undergo plasticity, activity can regulate their levels and secretion, and they regulate both synaptic transmission and neuronal growth. Although numerous experiments show demonstrable effects of neurotrophins on synaptic plasticity, the rules and mechanisms by which they exert their effects remain intriguingly elusive.
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Affiliation(s)
- A K McAllister
- Howard Hughes Medical Institute, Salk Institute, La Jolla, California 92037, USA.
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29
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Buckland ME, Cunningham AM. Alterations in expression of the neurotrophic factors glial cell line-derived neurotrophic factor, ciliary neurotrophic factor and brain-derived neurotrophic factor, in the target-deprived olfactory neuroepithelium. Neuroscience 1999; 90:333-47. [PMID: 10188958 DOI: 10.1016/s0306-4522(98)00270-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Neuronal growth factors play an important role in the development and maintenance of the nervous system. In the olfactory system, neurogenesis and synapse formation occur not only during development but throughout life and it would be expected that growth factors play a significant role in these ongoing processes. We have examined the expression of three neurotrophic factors, glial cell line-derived neurotrophic factor, ciliary neurotrophic factor and brain-derived neurotrophic factor in the normal rat olfactory system and following synaptic target ablation (olfactory bulbectomy). We found that brain-derived neurotrophic factor immunoreactivity was confined to the horizontal basal cells of the olfactory neuroepithelium and was unaltered by bulbectomy. Glial cell line-derived neurotrophic factor immunoreactivity was present in the mature olfactory neurons and also their synaptic target cells in the olfactory bulb. Following bulbectomy, glial cell line-derived neurotrophic factor immunoreactivity was abolished from the neuroepithelium. Ciliary neurotrophic factor was present throughout the olfactory neuronal lineage with strongest immunoreactivity in the horizontal basal cells and mature olfactory neurons as well as several cell types in the olfactory bulb. Postbulbectomy, there was loss of strong ciliary neurotrophic factor immunoreactivity in olfactory neurons, however, low levels persisted in the remaining neuronal population. Horizontal basal cell immunoreactivity persisted over three months. Our results would be consistent with glial cell line-derived neurotrophic factor expression in mature olfactory neurons being dependent upon functional synaptic contact with the olfactory bulb. Alternatively, this factor may be acting as target-derived growth factor for olfactory neurons, a role in keeping with its function in spinal motoneurons and in the nigrostriatal system. Brain-derived neurotrophic factor is implicated in the trophic support of immature neurons. Ciliary neurotrophic factor is clearly important in this unique neuronal system but elucidation of its role awaits further investigation.
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Affiliation(s)
- M E Buckland
- Neurobiology Program, The Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, NSW, Australia
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30
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Clarke PG, Posada A, Primi MP, Castagné V. Neuronal death in the central nervous system during development. Biomed Pharmacother 1998; 52:356-62. [PMID: 9856281 DOI: 10.1016/s0753-3322(99)80002-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
About half the neurons in the brain die at the time when their connections are being formed. This neuronal death is regulated by anterograde and retrograde signals that reflect both electrical activity and the uptake of trophic factors. Our recent data on the isthmo-optic projection indicate that there are in fact two different retrograde signals: a slow-acting survival signal mediated by a neurotrophin, and a fast-acting death signal mediated by calcium entry due to electrical activity in the presynaptic terminals. The developmental roles of the cell death are not well understood, but they appear to include the elimination of aberrant connections. The intracellular mechanisms of the cell death may not always correspond to the apoptotic ones so thoroughly investigated in vitro, because only one of the three morphological types occurring regularly in vivo resembles apoptosis. However, our experiments on retinal ganglion cells indicate that several apoptotic mechanisms apply in this particular in vivo situation: these include an involvement of oxygenated free radicals and glutathione, cell cycle-related events, and probably the synthesis of proteins promoting neuroprotection or cell death.
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Affiliation(s)
- P G Clarke
- IBCM, University of Lausanne, Switzerland
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31
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Panchision DM, Martin-DeLeon PA, Takeshima T, Johnston JM, Shimoda K, Tsoulfas P, McKay RD, Commissiong JW. An immortalized, type-1 astrocyte of mesencephalic origin source of a dopaminergic neurotrophic factor. J Mol Neurosci 1998; 11:209-21. [PMID: 10344791 DOI: 10.1385/jmn:11:3:209] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Rat embryonic d 14 (E14) mesencephalic cells, 2.5% of which are glioblasts, were incubated in medium containing 10% of fetal bovine serum for 12 h and subsequently expanded in a serum-free medium using basic fibroblast growth factor (bFGF) as the mitogen. On a single occasion, after more than 15 d in culture, several islets of proliferating, glial-like cells were observed in one dish. The cells, when isolated and passaged, proliferated rapidly in either a serum-free or serum-containing growth medium. Subsequent immunocytochemical analysis showed that they stained positive for GFAP and vimentin, and negative for A2B5, O4, GalC, and MAP2. Serum-free conditioned medium (CM) prepared from these cells caused a fivefold increase in survival and promoted neuritic expansion of E14 mesencephalic dopaminergic neurons in culture. These actions are similar to those exerted by CM derived from primary, mesencephalic type-1 astrocytes. The pattern of expression of the region-selective genes; wnt-1, en-1, sis showed that 70% of the cells were heteroploid, and of these, 50% were tetraploid. No apparent decline in proliferative capacity has been observed after 25 passages. The properties of this cell line, named ventral mesencephalic cell line one (VMCL1), are consistent with those of an immortalized, type-1 astrocyte. The mesencephalic origin of the cell line, and the pattern and potency of the neurotrophic activity exerted by the CM, strongly suggest that the neurotrophic factor(s) identified are novel, and will likely be strong candidates with clinical utility for the treatment of Parkinson's disease.
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Affiliation(s)
- D M Panchision
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-4092, USA
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32
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Spalding KL, Cui Q, Harvey AR. The effects of central administration of neurotrophins or transplants of fetal tectal tissue on retinal ganglion cell survival following removal of the superior colliculus in neonatal rats. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1998; 107:133-42. [PMID: 9602096 DOI: 10.1016/s0165-3806(98)00010-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In neonatal rats, intraocular injections of brain-derived neurotrophic factor (BDNF) or neurotrophin 4/5 (NT-4/5) enhance the survival of retinal ganglion cells (RGCs) following superior colliculus (SC) ablation [Q. Cui, A.R. Harvey, At least two mechanisms are involved in the death of retinal ganglion cells following target ablation in neonatal rats, J. Neurosci., 15, 1995, pp. 8143-8155.]. The aim of the present study was to determine if: (i) fetal tectal tissue grafted into the lesion site, or (ii) neurotrophins applied centrally to the injured SC, also decreased lesion-induced RGC death. Nuclei of tectally projecting RGCs were identified by injecting diamidino yellow (DY) into the left SC of 2-day-old (P2) Wistar rats. Injected SCs were lesioned at P4. In some animals, embryonic (E16) tectal tissue was then implanted into the lesion cavity; host rats were perfused 24 h or 20 days later. In short-term (24-h) studies, the number of DY-labelled pyknotic profiles was compared to the number of normal DY-labelled RGCs in retinal wholemounts (right eyes). The proportion of dying RGCs in animals with grafts (10.7%, n = 17) was not significantly different from lesion-only rats (13.2%, n = 26). Nonetheless, the long-term (20-day) study showed that, in most rats, fetal tectal tissue survived in the lesion cavity and in some cases, the grafts received host retinal input. In another group, different doses of BDNF or NT-4/5 were applied to the SC after P4 tectal lesions. Rats were perfused 24 h later and the number of pyknotic vs. normal DY-labelled RGCs was determined. Initial trials in which SC lesions were filled with gelfoam soaked in BDNF or NT-4/5 were unsuccessful; however, RGC death was reduced (p < 0.05, Dunnett's test) in rats that received gelfoam implants as well as focal neurotrophin injections into SC rostral to the lesion. The lowest pyknotic rate in individual animals from the BDNF and NT-4/5 groups was 2.41% and 2.01%, respectively. Overall, the proportion of dying RGCs was 7.0% (n = 8) for BDNF and 7.4% (n = 17) for NT-4/5 treated rats. Normal RGC densities were also significantly higher in these animals. NT-4/5 topically applied to the posterior surface of the eye did not reduce RGC death. The data show that the viability of injured neonatal RGCs is increased by specific retrograde neurotrophin-mediated survival signals which can be activated from the SC.
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Affiliation(s)
- K L Spalding
- Department of Anatomy and Human Biology, University of Western Australia, Nedlands, Perth, Australia
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33
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Rudge JS, Mather PE, Pasnikowski EM, Cai N, Corcoran T, Acheson A, Anderson K, Lindsay RM, Wiegand SJ. Endogenous BDNF protein is increased in adult rat hippocampus after a kainic acid induced excitotoxic insult but exogenous BDNF is not neuroprotective. Exp Neurol 1998; 149:398-410. [PMID: 9500963 DOI: 10.1006/exnr.1997.6737] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Systemic administration of the excitotoxin kainic acid to adult rats results in a well defined pattern of loss of the CA1 and CA3 pyramidal neurons of the hippocampus. Prior to this neuronal loss, brain-derived neurotrophic factor (BDNF) mRNA is substantially increased. We show here that BDNF protein is increased after excitotoxic insult in specific areas of the hippocampus, reaching maximal levels 24 h after the insult. BDNF protein levels in the hippocampus increase in direct relation to the severity of seizure. Up to 7 days after injection of kainic acid, levels of full-length TrkB protein were unchanged, whereas levels of truncated TrkB protein were significantly increased by 12 h. To determine whether elevations in BDNF protein levels are potentially beneficial to hippocampal neurons exposed to an excitotoxic stress, we infused exogenous BDNF prior to and during the period of neuronal death caused by kainic acid. We find that administration of high levels of exogenous BDNF does not affect severity of seizure, but does in fact, exacerbate the injury caused by kainic acid, specifically to CA3 pyramidal neurons. Although there was a trend toward sparing of CA1 pyramidal neurons on the side infused with BDNF, this was not significant. In the same paradigm, infusion of exogenous NT-3 had no effect.
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Affiliation(s)
- J S Rudge
- Regeneron Pharmaceuticals, Inc., Tarrytown, New York 10591, USA
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34
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Peripheral target regulation of the development and survival of spinal sensory and motor neurons in the chick embryo. J Neurosci 1998. [PMID: 9412513 DOI: 10.1523/jneurosci.18-01-00356.1998] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Unilateral limb-bud removal (LBR) before the outgrowth of sensory or motor neurons to the leg of chick embryos was used to examine the role of limb (target)-derived signals in the development and survival of lumbar motoneurons and sensory neurons in the dorsal root ganglia (DRG). After LBR, motor and sensory neurons underwent normal initial histological differentiation, and cell growth in both populations was unaffected. Before their death, target-deprived motoneurons also expressed a cell-specific marker, the homeodomain protein islet-1. Proliferation of sensory and motor precursor cells was also unaffected by LBR, and the migration of neural crest cells to the DRG and of motoneurons into the ventral horn occurred normally. During the normal period of programmed cell death (PCD), increased numbers of both sensory and motor neurons degenerated after LBR. However, whereas motoneuron loss increased by 40-50% (90% total), only approximately 25% more sensory neurons degenerated after LBR. A significant number of the surviving sensory neurons projected to aberrant targets in the tail after LBR, and many of these were lost after ablation of both the limb and tail. Treatment with neurotrophic factors (or muscle extract) rescued sensory and motor neurons from cell death after LBR without affecting precursor proliferation of either population. Activity blockade with curare failed to rescue motoneurons after LBR, and combined treatment with curare plus muscle extract was no more effective than muscle extract alone. Treatment with the antioxidant N-acetylcysteine rescued motoneurons from normal cell death but not after LBR. Two specific inhibitors of the interleukin beta1 converting enzyme (ICE) family of cysteine proteases also failed to prevent motoneuron death after LBR. Taken together these data provide definitive evidence that the loss of spinal neurons after LBR cannot be attributed to altered proliferation, migration, or differentiation. Rather, in the absence of limb-derived trophic signals, the affected neurons fail to survive and undergo PCD. Although normal cell death and cell death after target deprivation share many features in common, the intracellular pathways of cell death in the two may be distinct.
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35
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36
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Affiliation(s)
- B J Schnapp
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
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37
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Abstract
The field of neurotrophic factor pharmacology emerged during the past decade with the discovery that these proteins can counteract neuronal atrophy and death in the adult nervous system. These concepts are being tested in clinical trials. Therapeutic use of neurotrophic proteins seems practical for diseases of the peripheral nervous system (PNS), where they can be given by systemic administration. For diseases of the CNS, special administration strategies will have to be developed to deliver the neurotrophic factors into the brain. The development of small molecule mimetics represents an alternative approach that is actively pursued to provide brain-penetrant neurotrophics.
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Affiliation(s)
- F Hefti
- Neuroscience Research Centre, Merck Sharp & Dohme, Harlow, Essex, United Kingdom
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38
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Johanson SO, Crouch MF, Hendry IA. Signal transduction from membrane to nucleus: the special case for neurons. Neurochem Res 1996; 21:779-85. [PMID: 8873082 DOI: 10.1007/bf02532300] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Neurons have a unique problem with signal transduction from the membrane in the region of their terminals back to the cell body and nucleus. This distance may be several meters in some nerves in some species, so there is a requirement for some mechanism to stabilize the signal. This review examines two complementary mechanisms for this signal transduction, either by the retrograde axonal transport of the neurotrophic factor together with its receptor, or the transport of a stable activated second messenger molecule. Extrapolation of studies on the fibroblast signal transduction pathway, where it has been shown that G1 can translocate from the membrane to the nucleus, has led to the demonstration of the retrograde axonal transport of several putative signaling molecules. The alpha subunits of both G1 and Gz are retrogradely transported and Gz alpha or possibly the intact heterotrimeric Gz subsequently accumulates in dorsal root ganglia nuclei. Thus Gz1 Gi1 and potentially other G-proteins and distinct signaling molecules may provide additional signal transduction pathways to that of the neurotrophins from terminal to nucleus.
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Affiliation(s)
- S O Johanson
- Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra, Australia
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