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Sui P, Watanabe H, Ossipov MH, Bakalkin G, Artemenko K, Bergquist J. Proteomics of Neuropathic Pain: Proteins and Signaling Pathways Affected in a Rat Model. J Proteome Res 2014; 13:3957-65. [DOI: 10.1021/pr500241q] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
| | | | - Michael H. Ossipov
- Department
of Pharmacology, University of Arizona Health Sciences Center, 1501
North Campbell Avenue, Tucson, Arizona 85724, United States
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2
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Biological Mechanisms of Physical Activity in Preventing Cognitive Decline. Cell Mol Neurobiol 2009; 30:493-503. [DOI: 10.1007/s10571-009-9488-x] [Citation(s) in RCA: 219] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 12/14/2009] [Indexed: 02/07/2023]
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3
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Gómez-Pinilla F, Huie JR, Ying Z, Ferguson AR, Crown ED, Baumbauer KM, Edgerton VR, Grau JW. BDNF and learning: Evidence that instrumental training promotes learning within the spinal cord by up-regulating BDNF expression. Neuroscience 2007; 148:893-906. [PMID: 17719180 PMCID: PMC3225191 DOI: 10.1016/j.neuroscience.2007.05.051] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Revised: 04/24/2007] [Accepted: 05/22/2007] [Indexed: 10/22/2022]
Abstract
We have previously shown that the spinal cord is capable of learning a sensorimotor task in the absence of supraspinal input. Given the action of brain-derived neurotrophic factor (BDNF) on hippocampal learning, the current studies examined the role of BDNF in spinal learning. BDNF is a strong synaptic facilitator and, in association with other molecular signals (e.g. cAMP-response element binding protein (CREB), calcium/calmodulin activated protein kinase II (CaMKII) and synapsin I), important for learning. Spinally transected rats given shock to one hind leg when the leg extended beyond a selected threshold exhibited a progressive increase in flexion duration that minimized shock exposure, a simple form of instrumental learning. Instrumental learning resulted in elevated mRNA levels of BDNF, CaMKII, CREB, and synapsin I in the lumbar spinal cord region. The increases in BDNF, CREB, and CaMKII were proportional to the learning performance. Prior work has shown that instrumental training facilitates learning when subjects are tested on the contralateral leg with a higher response criterion. Pretreatment with the BDNF inhibitor TrkB-IgG blocked this facilitatory effect, as did the CaMKII inhibitor AIP. Intrathecal administration of BDNF facilitated learning when subjects were tested with a high response criterion. The findings indicate that instrumental training enables learning and elevates BDNF mRNA levels within the lumbar spinal cord. BDNF is both necessary, and sufficient, to produce the enabling effect.
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Affiliation(s)
- F Gómez-Pinilla
- Division of Neurosurgery, UCLA Brain Injury Research Center, USA.
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4
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Vaynman S, Gomez-Pinilla F. License to run: exercise impacts functional plasticity in the intact and injured central nervous system by using neurotrophins. Neurorehabil Neural Repair 2006; 19:283-95. [PMID: 16263961 DOI: 10.1177/1545968305280753] [Citation(s) in RCA: 287] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Exercise has been found to impact molecular systems important for maintaining neural function and plasticity. A characteristic finding for the effects of exercise in the brain and spinal cord has been the up-regulation of brain-derived neurotrophic factor (BDNF). This review focuses on the ability of exercise to impact brain circuitry by promoting neuronal repair and enhance learning and memory by increasing neurotrophic support. A paragon for the role of activity-dependent neurotrophins in the CNS is the capacity of BDNF to facilitate synaptic function and neuronal excitability. The authors discuss the effects of exercise in the intact and injured brain and spinal cord injury and the implementation of exercise preinjury and postinjury. As the CNS displays a capacity for plasticity throughout one's lifespan, exercise may be a powerful lifestyle implementation that could be used to augment synaptic plasticity, promote behavioral rehabilitation, and counteract the deleterious effects of aging.
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Affiliation(s)
- Shoshanna Vaynman
- Department of Neurosurgery and Physiological Science, and Brain Injury Research Center, UCLA School of Medicine, Los Angeles, CA 90095, USA
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5
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Vaynman SS, Ying Z, Yin D, Gomez-Pinilla F. Exercise differentially regulates synaptic proteins associated to the function of BDNF. Brain Res 2006; 1070:124-30. [PMID: 16413508 DOI: 10.1016/j.brainres.2005.11.062] [Citation(s) in RCA: 189] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Revised: 11/02/2005] [Accepted: 11/06/2005] [Indexed: 11/28/2022]
Abstract
We explored the capacity of exercise to impact select events comprising synaptic transmission under the direction of brain-derived neurotrophic factor (BDNF), which may be central to the events by which exercise potentiates synaptic function. We used a specific immunoadhesin chimera (TrkB-IgG) that mimics the BDNF receptor, TrkB, to selectively block BDNF in the hippocampus during 3 days of voluntary wheel running. We measured resultant synapsin I, synaptophysin, and syntaxin levels involved in vesicular pool formation, endocytosis, and exocytosis, respectively. Synapsin I is involved in vesicle pool formation and neurotransmitter release, synaptophysin, in the biogenesis of synaptic vesicles and budding, and syntaxin, in vesicle docking and fusion. Exercise preferentially increased synapsin I and synaptophysin levels, without affecting syntaxin. There was a positive correlation between synapsin I and synaptophysin in exercising rats and synapsin I with the amount of exercise. Blocking BDNF abrogated the exercise-induced increases in synapsin I and synatophysin, revealing that exercise regulates select properties of synaptic transmission under the direction of BDNF.
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Affiliation(s)
- Shoshanna S Vaynman
- Department of Physiological Science, UCLA, 621 Charles E. Young Drive, Los Angeles, CA 90095, USA
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6
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Vaynman S, Gomez-Pinilla F. Revenge of the “Sit”: How lifestyle impacts neuronal and cognitive health through molecular systems that interface energy metabolism with neuronal plasticity. J Neurosci Res 2006; 84:699-715. [PMID: 16862541 DOI: 10.1002/jnr.20979] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Exercise, a behavior that is inherently associated with energy metabolism, impacts the molecular systems important for synaptic plasticity and learning and memory. This implies that a close association must exist between these systems to ensure proper neuronal function. This review emphasizes the ability of exercise and other lifestyle implementations that modulate energy metabolism, such as diet, to impact brain function. Mechanisms believed to interface metabolism and cognition seem to play a critical role with the brain derived neurotrophic factor (BDNF) system. Behaviors concerned with activity and metabolism may have developed simultaneously and interdependently during evolution to determine the influence of exercise and diet on cognition. A look into our evolutionary past indicates that our genome remains unchanged from the times of our hunter-gatherer ancestors, whose active lifestyle predominated throughout almost 100% of humankind's existence. Consequently, the sedentary lifestyle and eating behaviors enabled by the comforts of technologic progress may be reaping "revenge" on the health of both our bodies and brains. In the 21st century we are confronted by the ever-increasing incidence of metabolic disorders in both the adult and child population. The ability of exercise and diet to impact systems that promote cell survival and plasticity may be applicable for combating the deleterious effects of disease and ageing on brain health and cognition.
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Affiliation(s)
- Shoshanna Vaynman
- Department of Neurosurgery and Physiological Science and Brain Injury Research Center, UCLA School of Medicine, Los Angeles, California 90095, USA
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7
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Ding Q, Vaynman S, Akhavan M, Ying Z, Gomez-Pinilla F. Insulin-like growth factor I interfaces with brain-derived neurotrophic factor-mediated synaptic plasticity to modulate aspects of exercise-induced cognitive function. Neuroscience 2006; 140:823-33. [PMID: 16650607 DOI: 10.1016/j.neuroscience.2006.02.084] [Citation(s) in RCA: 373] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 02/16/2006] [Accepted: 02/24/2006] [Indexed: 12/21/2022]
Abstract
The ability of exercise to benefit neuronal and cognitive plasticity is well recognized. This study reveals that the effects of exercise on brain neuronal and cognitive plasticity are in part modulated by a central source of insulin-like growth factor-I. Exercise selectively increased insulin-like growth factor-I expression without affecting insulin-like growth factor-II expression in the rat hippocampus. To determine the role that insulin-like growth factor-I holds in mediating exercise-induced neuronal and cognitive enhancement, a specific antibody against the insulin-like growth factor-I receptor was used to block the action of insulin-like growth factor-I in the hippocampus during a 5-day voluntary exercise period. A two-trial-per-day Morris water maze was performed for five consecutive days, succeeded by a probe trial 2 days later. Blocking hippocampal insulin-like growth factor-I receptors did not significantly attenuate the ability of exercise to enhance learning acquisition, but abolished the effect of exercise on augmenting recall. Blocking the insulin-like growth factor-I receptor significantly reversed the exercise-induced increase in the levels of brain-derived neurotrophic factor mRNA and protein and pro-brain-derived neurotrophic factor protein, suggesting that the effects of insulin-like growth factor-I may be partially accomplished by modulating the precursor to the mature brain-derived neurotrophic factor. A molecular analysis revealed that exercise significantly elevated proteins downstream to brain-derived neurotrophic factor activation important for synaptic function, i.e. synapsin I, and signal transduction cascades associated with memory processes, i.e. phosphorylated calcium/calmodulin protein kinase II and phosphorylated mitogen-activated protein kinase II. Blocking the insulin-like growth factor-I receptor abolished these exercise-induced increases. Our results illustrate a possible mechanism by which insulin-like growth factor-I interfaces with the brain-derived neurotrophic factor system to mediate exercise-induced synaptic and cognitive plasticity.
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Affiliation(s)
- Q Ding
- Department of Physiological Science, UCLA, 621 Charles E. Young Drive, Los Angeles, CA 90095, USA
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8
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Vaynman S, Ying Z, Gomez-Pinilla F. Hippocampal BDNF mediates the efficacy of exercise on synaptic plasticity and cognition. Eur J Neurosci 2005; 20:2580-90. [PMID: 15548201 DOI: 10.1111/j.1460-9568.2004.03720.x] [Citation(s) in RCA: 981] [Impact Index Per Article: 51.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We found that a short exercise period enhanced cognitive function on the Morris water maze (MWM), such that exercised animals were significantly better than sedentary controls at learning and recalling the location of the platform. The finding that exercise increased brain-derived neurotrophic factor (BDNF), a molecule important for synaptic plasticity and learning and memory, impelled us to examine whether a BDNF-mediated mechanism subserves the capacity of exercise to improve hippocampal-dependent learning. A specific immunoadhesin chimera (TrkB-IgG), that mimics the BDNF receptor, TrkB, to selectively bind BDNF molecules, was used to block BDNF in the hippocampus during a 1-week voluntary exercise period. After this, a 2-trial-per-day MWM was performed for 5 consecutive days, succeeded by a probe trial 2 days later. By inhibiting BDNF action we blocked the benefit of exercise on cognitive function, such that the learning and recall abilities of exercising animals receiving the BDNF blocker were reduced to sedentary control levels. Inhibiting BDNF action also blocked the effect of exercise on downstream systems regulated by BDNF and important for synaptic plasticity, cAMP response-element-binding protein (CREB) and synapsin I. Specific to exercise, we found an association between CREB and BDNF expression and cognitive function, such that animals who were the fastest learners and had the best recall showed the highest expression of BDNF and associated CREB mRNA levels. These findings suggest a functional role for CREB under the control of BDNF in mediating the exercise-induced enhancement in learning and memory. Our results indicate that synapsin I might also contribute to this BDNF-mediated mechanism.
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Affiliation(s)
- Shoshanna Vaynman
- Department of Physiological Science, UCLA, 621 Charles E. Young Drive, Los Angeles, CA 90095, USA
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9
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Molteni R, Zheng JQ, Ying Z, Gómez-Pinilla F, Twiss JL. Voluntary exercise increases axonal regeneration from sensory neurons. Proc Natl Acad Sci U S A 2004; 101:8473-8. [PMID: 15159540 PMCID: PMC420418 DOI: 10.1073/pnas.0401443101] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Recent advances in understanding the role of neurotrophins on activity-dependent plasticity have provided insight into how behavior can affect specific aspects of neuronal biology. We present evidence that voluntary exercise can prime adult dorsal root ganglion neurons for increased axonal regeneration through a neurotrophin-dependent mechanism. Dorsal root ganglion neurons showed an increase in neurite outgrowth when cultured from animals that had undergone 3 or 7 days of exercise compared with sedentary animals. Neurite length over 18-22 h in culture correlated directly with the distance that animals ran. The exercise-conditioned animals also showed enhanced regrowth of axons after an in vivo nerve crush injury. Sensory ganglia from the 3- and 7-day-exercised animals contained higher brain-derived neurotrophic factor, neurotrophin 3, synapsin I, and GAP43 mRNA levels than those from sedentary animals. Consistent with the rise in brain-derived neurotrophic factor and neurotrophin 3 during exercise, the increased growth potential of the exercise-conditioned animals required activation of the neurotrophin signaling in vivo during the exercise period but did not require new mRNA synthesis in culture.
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Affiliation(s)
- Raffaella Molteni
- Department of Neurosurgery, University of California, Los Angeles, CA 90095, USA
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10
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Wu A, Ying Z, Gomez-Pinilla F. The interplay between oxidative stress and brain-derived neurotrophic factor modulates the outcome of a saturated fat diet on synaptic plasticity and cognition. Eur J Neurosci 2004; 19:1699-707. [PMID: 15078544 DOI: 10.1111/j.1460-9568.2004.03246.x] [Citation(s) in RCA: 280] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A diet high in saturated fat (HF) decreases levels of brain-derived neurotrophic factor (BDNF), to the extent that compromises neuroplasticity and cognitive function, and aggravates the outcome of brain insult. By using the antioxidant power of vitamin E, we performed studies to determine the role of oxidative stress as a mediator for the effects of BDNF on synaptic plasticity and cognition caused by consumption of the HF diet. Male adult rats were maintained on a HF diet for 2 months with or without 500 IU/kg of vitamin E. Supplementation of the HF diet with vitamin E dramatically reduced oxidative damage, normalized levels of BDNF, synapsin I and cyclic AMP-response element-binding protein (CREB), caused by the consumption of the HF diet. In addition, vitamin E supplementation preserved the process of activation of synapsin I and CREB, and reversed the HF-impaired cognitive function. It is known that BDNF facilitates the synapse by modulating synapsin I and CREB, which have been implicated in synaptic plasticity associated to learning and memory. These results show that oxidative stress can interact with the BDNF system to modulate synaptic plasticity and cognitive function. Therefore, studies appear to reveal a mechanism by which events classically related to the maintenance of energy balance of the cell, such as oxidative stress, can interact with molecular events that modulate neuronal and behavioural plasticity.
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Affiliation(s)
- Aiguo Wu
- Department of Physiological Science, University of California at Los Angeles, 621 Charles E. Young Drive, Los Angeles, California 90095, USA
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11
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Hurley SL, Brown DL, Cheetham JJ. Cytoskeletal interactions of synapsin I in non-neuronal cells. Biochem Biophys Res Commun 2004; 317:16-23. [PMID: 15047142 DOI: 10.1016/j.bbrc.2004.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2003] [Indexed: 01/21/2023]
Abstract
Synapsin I is a neuronal phosphoprotein involved in the localization and stabilization of synaptic vesicles. Recently, synapsin I has been detected in several non-neuronal cell lines, but its function in these cells is unclear. To determine the localization of synapsin I in non-neuronal cells, it was transiently expressed in HeLa and NIH/3T3 cells as an enhanced green fluorescent protein fusion protein. Synapsin I-enhanced green fluorescent protein colocalized with F-actin in both cell lines, particularly with microspikes and membrane ruffles. It did not colocalize with microtubules or vimentin and it did not cause major alterations in cytoskeletal organization. Synapsin Ia-enhanced green fluorescent protein colocalized with microtubule bundles in taxol-treated HeLa cells and with F-actin spots at the plasma membrane in cells treated with cytochalasin B. It did not noticeably affect F-actin reassembly following drug removal. Synapsin Ia-enhanced green fluorescent protein remained colocalized with F-actin in cells treated with nocodazole, and it did not affect reassembly of microtubules following drug removal. These results demonstrate that synapsin I interacts with F-actin in non-neuronal cells and suggest that synapsin I may have a role in regions where actin is highly dynamic.
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Affiliation(s)
- Sandra L Hurley
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ont, Canada K1S 5B6
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12
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Vaynman S, Ying Z, Gómez-Pinilla F. Exercise induces BDNF and synapsin I to specific hippocampal subfields. J Neurosci Res 2004; 76:356-62. [PMID: 15079864 DOI: 10.1002/jnr.20077] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
To assess the relationship between brain-derived neurotrophic factor (BDNF) and synapsin I in the hippocampus during exercise, we employed a novel microsphere injection method to block the action of BDNF through its tyrosine kinase (Trk) receptor and subsequently measure the mRNA levels of synapsin I, using real-time TaqMan RT-PCR for RNA quantification. After establishing a causal link between BDNF and exercise-induced synapsin I mRNA levels, we studied the exercise-induced distribution of BDNF and synapsin I in the rodent hippocampus. Quantitative immunohistochemical analysis revealed increases of BDNF and synapsin I in CA3 stratum lucidum and dentate gyrus, and synapsin I alone in CA1 stratum radiatum and stratum laconosum moleculare. These results indicate that exercise induces plasticity of select hippocampal transsynaptic circuitry, possibly comprising a spatial restriction on synapsin I regulation by BDNF.
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Affiliation(s)
- Shoshanna Vaynman
- Department of Physiological Science, UCLA, Los Angeles, California 90095, USA
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13
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Wu A, Molteni R, Ying Z, Gomez-Pinilla F. A saturated-fat diet aggravates the outcome of traumatic brain injury on hippocampal plasticity and cognitive function by reducing brain-derived neurotrophic factor. Neuroscience 2003; 119:365-75. [PMID: 12770552 DOI: 10.1016/s0306-4522(03)00154-4] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We have conducted studies to determine the potential of dietary factors to affect the capacity of the brain to compensate for insult. Rats were fed with a high-fat sucrose (HFS) diet, a popularly consumed diet in industrialized western societies, for 4 weeks before a mild fluid percussion injury (FPI) or sham surgery was performed. FPI impaired spatial learning capacity in the Morris water maze, and these effects were aggravated by previous exposure of the rats to the action of the HFS diet. Learning performance decreased according to levels of brain-derived neurotrophic factor (BDNF) in individual rats, such that rats with the worst learning efficacy showed the lowest levels of BDNF in the hippocampus. BDNF immunohistochemistry localized the decreases in BDNF to the CA3 and dentate gyrus of the hippocampal formation. BDNF has a strong effect on synaptic plasticity via the action of synapsin I and cAMP-response element-binding protein (CREB), therefore, we assessed changes in synapsin I and CREB in conjunction with BDNF. Levels of synapsin I and CREB decreased in relation to decreases in BDNF levels. The combination of FPI and the HFS diet had more dramatic effects on the active state (phosphorylated) of synapsin I and CREB. There were no signs of neurodegeneration in the hippocampus of any rat group assessed with Fluoro-Jade B staining. The results suggest that FPI and diet impose a risk factor to the molecular machinery in charge of maintaining neuronal function under homeostatic and challenging situations.
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Affiliation(s)
- A Wu
- Department of Physiological Science, University of California at Los Angeles, 621 Charles E Young Drive, Los Angeles, CA H-1450, USA
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14
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Koirala S, Qiang H, Ko CP. Reciprocal interactions between perisynaptic Schwann cells and regenerating nerve terminals at the frog neuromuscular junction. JOURNAL OF NEUROBIOLOGY 2000; 44:343-60. [PMID: 10942887 DOI: 10.1002/1097-4695(20000905)44:3<343::aid-neu5>3.0.co;2-o] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The perisynaptic Schwann cell (PSC) has gained recent attention with respect to its roles in synaptic function, remodeling, and regeneration at the vertebrate neuromuscular junction (NMJ). Here we test the hypothesis that, following nerve injury, processes extended by PSCs guide regenerating nerve terminals (NTs) in vivo, and that the extension of sprouts by PSCs is triggered by the arrival of regenerating NTs. Frog NMJs were double-stained with a fluorescent dye, FM4-64, for NTs, and fluorescein isothiocyanate (FITC)-tagged peanut agglutinin (PNA) for PSCs. Identified NMJs were imaged in vivo repeatedly for several months after nerve injury. PSCs sprouted profusely beginning 3-4 weeks after nerve transection and, as reinnervation progressed, regenerating NTs closely followed the preceding PSC sprouts, which could extend tens to hundreds of microns beyond the original synaptic site. The pattern of reinnervation was dictated by PSC sprouts, which could form novel routes joining neighboring junctions or develop into new myelinated axonal pathways. In contrast to mammals, profuse PSC sprouting in frog muscles was not seen in response to axotomy alone, and did not occur at chronically denervated NMJs. Instead, sprouting coincided with the arrival of regenerating NTs. Immunofluorescent staining revealed that in muscle undergoing reinnervation 4 weeks after axotomy, 91% of NMJs bore PSC sprouts, compared to only 6% of NMJs in muscle that was chronically denervated for 4 weeks. These results suggest that reciprocal interactions between regenerating NTs and PSCs govern the process of reinnervation at frog NMJs: regenerating NTs induce PSCs to sprout, and PSC sprouts, in turn, lead and guide the elaboration of NTs.
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Affiliation(s)
- S Koirala
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089-2520, USA
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15
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Morihara T, Mizoguchi A, Takahashi M, Kozaki S, Tsujihara T, Kawano S, Shirasu M, Ohmukai T, Kitada M, Kimura K, Okajima S, Tamai K, Hirasawa Y, Ide C. Distribution of synaptosomal-associated protein 25 in nerve growth cones and reduction of neurite outgrowth by botulinum neurotoxin A without altering growth cone morphology in dorsal root ganglion neurons and PC-12 cells. Neuroscience 1999; 91:695-706. [PMID: 10366026 DOI: 10.1016/s0306-4522(98)00671-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Synaptosomal-associated protein 25 has been regarded as one of the target-associated soluble N-ethylmaleimide-sensitive fusion attachment protein receptors essential for exocytosis of vesicles in synapses. We have previously reported that cleavage of syntaxin, which is another target-associated soluble N-ethylmaleimide-sensitive fusion attachment protein receptor, with botulinum neurotoxin C1 resulted in inhibition of neurite extension and morphological changes including growth cone collapse and large vacuole formation. As an attempt to explore the mechanism of growth cone extension, we examined the ultrastructural localization of synaptosomal-associated protein 25 in growth cones with or without treatment of botulinum neurotoxin A, which cleaves synaptosomal-associated protein 25. In dorsal root ganglion neurons, light microscopy demonstrated synaptosomal-associated protein 25 immunoreactivity throughout the neurons, including the cell bodies, neurites and growth cones. Using electron microscopy, gold signals immunoreactive for synaptosomal-associated protein 25 were identified diffusely in the cytoplasm of the growth cones. In contrast, in PC-12 cells, a large number of gold signals were localized on the plasma membranes. High levels of signal were also found in the cytoplasm in the central region of the growth cones. We also confirmed that botulinum neurotoxin A treatment reduced neurite extension by about 50%. However, both in dorsal root ganglion neurons and in PC-12 cells we found no differences in the ultrastructure nor in the localization of synaptosomal-associated protein 25 between growth cones with and without toxin treatment. These results indicate that cleavage of synaptosomal-associated protein 25 inhibits growth cone extension in a manner different than that of syntaxin cleavage. The results of this study suggest the possibility that synaptosomal-associated protein 25 is involved in growth cone extension through a process independent of vesicle fusion.
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Affiliation(s)
- T Morihara
- Department of Anatomy and Neurobiology, Kyoto University Graduate School of Medicine, Japan
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Martí E, Ferrer I, Blasi J. Transient increase of synapsin-I immunoreactivity in the mossy fiber layer of the hippocampus after transient forebrain ischemia in the mongolian gerbil. Brain Res 1999; 824:153-60. [PMID: 10196445 DOI: 10.1016/s0006-8993(99)01158-0] [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: 11/16/2022]
Abstract
Synapsin-I is a vesicular phosphoprotein, which regulates neurotransmitter release, neurite development, and maturation of synaptic contacts during normal development and following various brain lesions in adulthood. In the present study, we have examined by immunohistochemistry possible modifications in the expression of synapsin-I in the hippocampus of Mongolian gerbils after transient forebrain ischemia. The animals were subjected to 5 min of transient forebrain ischemia through bilateral common carotid occlusion, and were examined at different time-points post-ischemia. Transient forebrain ischemia produces cell death of the majority of CA1 pyramidal neurons of the hippocampus and polymorphic hilar neurons of the dentate gyrus. This is followed by reactive changes, including synaptic reorganization and modifications in the expression of synaptic proteins, which provide the molecular bases of synaptic plasticity. Transient decrease of synapsin-I immunoreactivity was observed in the inner zone of the molecular layer of the dentate gyrus, thus suggesting denervation and posterior reinervation in this area. In addition, a strong increase in synapsin-I immunoreactivity was observed in the hilus of the dentate gyrus and in the mossy fiber layer of the hippocampus at 2, 4 and 7 days after ischemia. Parallel increases in synaptophysin immunoreactivity were not observed, thus suggesting a selective induction of synapsin-I after ischemia. The present results indicate that synapsin-I participates in the reactive response of granule cells to transient forebrain ischemia in the hippocampus of the gerbil, and suggest a role for this protein in the plastic adaptations of the hippocampus following injury.
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Affiliation(s)
- E Martí
- Departament de Biologia Cellular i Anatomia Patològica, Campus de Bellvitge, Universitat de Barcelona, C/Feixa Llarga s/n, 08907 L'Hospitalet de Llobregat, Spain.
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17
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Quatacker J, Partoens P, De Potter W. Differential ultrastructural distribution of synapsin and synaptophysin proximal to a ligation in bovine splenic nerve. Brain Res 1998; 802:281-4. [PMID: 9748630 DOI: 10.1016/s0006-8993(98)00617-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Synaptophysin and synapsin, closely correlated on synaptic vesicles in terminals, may show a differential distribution at synapse formation and maturation. In order to disclose the fine structural details of these differences, synapsin and synaptophysin distribution was studied by immunocytochemistry on ligated bovine splenic axons in vitro and compared with terminals in the vas deferens. In the synaptic differentiations taking place proximally synapsin could only be detected on the accumulating elements of the axonal reticulum. Large dense granules and clusters of small synaptic vesicles were negative. Synaptophysin was restricted to these clusters. In the vas deferens, co-localization of synapsin and synaptophysin could be seen on small vesicles. From their formation small synaptic vesicles carry synaptophysin. Synapsin may be involved in the dynamic membrane changes taking place at the ligation. At a functional terminal, synapsin shifts to small synaptic vesicles.
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Affiliation(s)
- J Quatacker
- Goormaghtigh Institute of Pathology, University Hospital, Ghent, Belgium.
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18
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Abstract
Peripheral nerve regeneration comprises the formation of axonal sprouts, their outgrowth as regenerating axons and the reinnervation of original targets. This review focuses on the morphological features of axonal sprouts at the node of Ranvier and their subsequent outgrowth guided by Schwann cells or by Schwann cell basal laminae. Adhesion molecules such as N-CAM, L1 and N-cadherin are involved in the axon-to-axon and axon-to-Schwann cell attachment, and it is suggested that integrins such as alpha 1 beta 1 and alpha 6 beta 1 mediate the attachment between axons and Schwann cell basal laminae. The presence of synaptic vesicle-associated proteins such as synaptophysin, synaptotagmin and synapsin I in the growth cones of regenerating axons indicates the possibility that exocytotic fusion of vesicles with the surface axolemma supplies the membranous components for the extension of regenerating axons. Almost all the subtypes of protein kinase C have been localized in growth cones both in vivo and in vitro. Protein kinase C and GAP-43 are implicated to be involved in at least some part of the adhesion of growth cones to the substrate and their growth activity. The significance of tyrosine kinase in growth cones is emphasized. Tyrosine kinase plays an important role in intracellular signal transduction of the growth of regenerating axons mediated by both nerve trophic factors and adhesion molecules. Growth factors such as NGF, BDNF, CNTF and bFGF are also discussed mainly in terms of the influence of Schwann cells on regenerating axons.
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Affiliation(s)
- C Ide
- Department of Anatomy and Neurobiology, Kyoto University, Faculty of Medicine, Japan
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