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Schneider M, Al-Shareffi E, Haltiwanger RS. Biological functions of fucose in mammals. Glycobiology 2018; 27:601-618. [PMID: 28430973 DOI: 10.1093/glycob/cwx034] [Citation(s) in RCA: 248] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Accepted: 04/13/2017] [Indexed: 12/13/2022] Open
Abstract
Fucose is a 6-deoxy hexose in the l-configuration found in a large variety of different organisms. In mammals, fucose is incorporated into N-glycans, O-glycans and glycolipids by 13 fucosyltransferases, all of which utilize the nucleotide-charged form, GDP-fucose, to modify targets. Three of the fucosyltransferases, FUT8, FUT12/POFUT1 and FUT13/POFUT2, are essential for proper development in mice. Fucose modifications have also been implicated in many other biological functions including immunity and cancer. Congenital mutations of a Golgi apparatus localized GDP-fucose transporter causes leukocyte adhesion deficiency type II, which results in severe developmental and immune deficiencies, highlighting the important role fucose plays in these processes. Additionally, changes in levels of fucosylated proteins have proven as useful tools for determining cancer diagnosis and prognosis. Chemically modified fucose analogs can be used to alter many of these fucose dependent processes or as tools to better understand them. In this review, we summarize the known roles of fucose in mammalian physiology and pathophysiology. Additionally, we discuss recent therapeutic advances for cancer and other diseases that are a direct result of our improved understanding of the role that fucose plays in these systems.
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Affiliation(s)
- Michael Schneider
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Esam Al-Shareffi
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA.,Department of Psychiatry, Georgetown University Hospital, Washington, DC 20007, USA
| | - Robert S Haltiwanger
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA.,Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
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2
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Age-dependent decrease in glomeruli and receptor cells containing α1-2 fucose glycan in the mouse main olfactory system but not in the vomeronasal system. Cell Tissue Res 2018; 373:361-366. [PMID: 29552725 DOI: 10.1007/s00441-018-2819-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 02/27/2018] [Indexed: 10/17/2022]
Abstract
Receptor cells of the olfactory epithelium (OE) and vomeronasal organ (VNO) project axons to glomeruli in the main olfactory bulb (MOB) and accessory olfactory bulb (AOB), respectively and undergo continuous turnover throughout life. Alpha1-2 fucose (α1-2Fuc) glycan mediates neurite outgrowth and synaptic plasticity and plays important roles in the formation of the olfactory system during development. We previously confirmed the localization of α1-2Fuc glycan in the olfactory system of 3- to 4-month-old mice but whether such localization persists throughout life remains unknown. Here, the MOB, AOB, OE and VNO of 1-, 3- and 8-month-old mice were histochemically examined using Ulex europaeus agglutinin-I (UEA-I) that specifically binds to α1-2Fuc glycan. Binding sites for UEA-I in the MOB were similar among all age groups but the ratio of UEA-I-positive glomeruli significantly decreased with aging. The frequency of UEA-I-positive receptor cells in the OE of the two older groups was also significantly lower than that of 1-month-old mice. On the other hand, UEA-I binding in the AOB and VNO did not significantly differ among all three groups. These findings suggest that the primary pathway of the main olfactory system requires the role of α1-2Fuc glycan in young mice rather than old mice, while the vomeronasal pathway equally requires this glycan in both young and old mice.
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Mountford C, Quadrelli S, Lin A, Ramadan S. Six fucose-α(1-2) sugars and α-fucose assigned in the human brain using in vivo two-dimensional MRS. NMR IN BIOMEDICINE 2015; 28:291-296. [PMID: 25534141 DOI: 10.1002/nbm.3239] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 11/02/2014] [Accepted: 11/05/2014] [Indexed: 06/04/2023]
Abstract
A growing body of literature has indicated that fucose-α(1-2)-galactose sugars are implicated in the molecular mechanisms that underlie neuronal development, learning and memory in the human brain. An understanding of the in vivo roles played by these terminal fucose residues has been hampered by the lack of technology to non-invasively monitor their levels in the human brain. We have implemented in vivo two-dimensional MRS technology to examine the human brain in a 3-T clinical MR scanner, and report that six fucose-α(1-2)-galactose residues and free α-fucose are available for inspection. Fucose-α(1-3)-galactose residues cannot yet be assigned using this technology as they resonate under the water resonance. This new application offers an unprecedented insight into the molecular mechanisms by which fucosylated sugars contribute to neuronal processes and how they alter during development, ageing and disease.
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Affiliation(s)
- Carolyn Mountford
- Centre for MR in Health, School of Health Sciences, University of Newcastle, Newcastle, New South Wales, Australia; Center for Clinical Spectroscopy, Department of Radiology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA
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Kondoh D, Tateno H, Hirabayashi J, Yasumoto Y, Nakao R, Oishi K. Molecular clock regulates daily α1-2-fucosylation of the neural cell adhesion molecule (NCAM) within mouse secondary olfactory neurons. J Biol Chem 2014; 289:36158-65. [PMID: 25384980 PMCID: PMC4276879 DOI: 10.1074/jbc.m114.571141] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 11/06/2014] [Indexed: 11/06/2022] Open
Abstract
The circadian clock regulates various behavioral and physiological rhythms in mammals. Circadian changes in olfactory functions such as neuronal firing in the olfactory bulb (OB) and olfactory sensitivity have recently been identified, although the underlying molecular mechanisms remain unknown. We analyzed the temporal profiles of glycan structures in the mouse OB using a high-density microarray that includes 96 lectins, because glycoconjugates play important roles in the nervous system such as neurite outgrowth and synaptogenesis. Sixteen lectin signals significantly fluctuated in the OB, and the intensity of all three that had high affinity for α1-2-fucose (α1-2Fuc) glycan in the microarray was higher during the nighttime. Histochemical analysis revealed that α1-2Fuc glycan is located in a diurnal manner in the lateral olfactory tract that comprises axon bundles of secondary olfactory neurons. The amount of α1-2Fuc glycan associated with the major target glycoprotein neural cell adhesion molecule (NCAM) varied in a diurnal fashion, although the mRNA and protein expression of Ncam1 did not. The mRNA and protein expression of Fut1, a α1-2-specific fucosyltransferase gene, was diurnal in the OB. Daily fluctuation of the α1-2Fuc glycan was obviously damped in homozygous Clock mutant mice with disrupted diurnal Fut1 expression, suggesting that the molecular clock governs rhythmic α1-2-fucosylation in secondary olfactory neurons. These findings suggest the possibility that the molecular clock is involved in the diurnal regulation of olfaction via α1-2-fucosylation in the olfactory system.
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Affiliation(s)
- Daisuke Kondoh
- From the Biological Clock Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8566, the Department of Basic Veterinary Medicine, Laboratory of Veterinary Anatomy, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555
| | - Hiroaki Tateno
- the Research Center for Stem Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568
| | - Jun Hirabayashi
- the Research Center for Stem Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568
| | - Yuki Yasumoto
- From the Biological Clock Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8566, the Department of Applied Biological Science, Graduate School of Science and Technology, Tokyo University of Science, Noda 278-8510, and
| | - Reiko Nakao
- From the Biological Clock Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8566
| | - Katsutaka Oishi
- From the Biological Clock Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8566, the Department of Applied Biological Science, Graduate School of Science and Technology, Tokyo University of Science, Noda 278-8510, and the Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8562, Japan
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5
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Madeo M, Kovács AD, Pearce DA. The human synaptic vesicle protein, SV2A, functions as a galactose transporter in Saccharomyces cerevisiae. J Biol Chem 2014; 289:33066-71. [PMID: 25326386 DOI: 10.1074/jbc.c114.584516] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
SV2A is a synaptic vesicle membrane protein expressed in neurons and endocrine cells and involved in the regulation of neurotransmitter release. Although the exact function of SV2A still remains elusive, it was identified as the specific binding site for levetiracetam, a second generation antiepileptic drug. Our sequence analysis demonstrates that SV2A has significant homology with several yeast transport proteins belonging to the major facilitator superfamily (MFS). Many of these transporters are involved in sugar transport into yeast cells. Here we present evidence showing, for the first time, that SV2A is a galactose transporter. We expressed human SV2A in hexose transport-deficient EBY.VW4000 yeast cells and demonstrated that these cells are able to grow on galactose-containing medium but not on other fermentable carbon sources. Furthermore, the addition of the SV2A-binding antiepileptic drug levetiracetam to the medium inhibited the galactose-dependent growth of hexose transport-deficient EBY.VW4000 yeast cells expressing human SV2A. Most importantly, direct measurement of galactose uptake in the same strain verified that SV2A is able to transport extracellular galactose inside the cells. The newly identified galactose transport capability of SV2A may have an important role in regulating/modulating synaptic function.
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Affiliation(s)
- Marianna Madeo
- From the Sanford Children's Health Research Center, Sanford Research, Sioux Falls, South Dakota 57104 and
| | - Attila D Kovács
- From the Sanford Children's Health Research Center, Sanford Research, Sioux Falls, South Dakota 57104 and
| | - David A Pearce
- From the Sanford Children's Health Research Center, Sanford Research, Sioux Falls, South Dakota 57104 and the Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, South Dakota, 57104
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6
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Maitre M, Roullot-Lacarrière V, Piazza PV, Revest JM. Western blot detection of brain phosphoproteins after performing Laser Microdissection and Pressure Catapulting (LMPC). J Neurosci Methods 2011; 198:204-12. [DOI: 10.1016/j.jneumeth.2011.04.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 02/23/2011] [Accepted: 04/01/2011] [Indexed: 01/31/2023]
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7
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Revest JM, Kaouane N, Mondin M, Le Roux A, Rougé-Pont F, Vallée M, Barik J, Tronche F, Desmedt A, Piazza PV. The enhancement of stress-related memory by glucocorticoids depends on synapsin-Ia/Ib. Mol Psychiatry 2010; 15:1125, 1140-51. [PMID: 20368707 PMCID: PMC2990189 DOI: 10.1038/mp.2010.40] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The activation of glucocorticoid receptors (GR) by glucocorticoids increases stress-related memory through the activation of the MAPK signaling pathway and the downstream transcription factor Egr-1. Here, using converging in vitro and in vivo approaches, respectively, GR-expressing cell lines, culture of hippocampal neurons, and GR genetically modified mice (GR(NesCre)), we identified synapsin-Ia/Ib as one of the effectors of the glucocorticoid signaling cascade. Stress and glucocorticoid-induced activation of the GR modulate synapsin-Ia/Ib through two complementary mechanisms. First, glucocorticoids driving Egr-1 expression increase the expression of synapsin-Ia/Ib, and second, glucocorticoids driving MAPK activation increase its phosphorylation. Finally, we showed that blocking fucosylation of synapsin-Ia/Ib in the hippocampus inhibits its expression and prevents the glucocorticoid-mediated increase in stress-related memory. In conclusion, our data provide a complete molecular pathway (GR/Egr-1/MAPK/Syn-Ia/Ib) through which stress and glucocorticoids enhance the memory of stress-related events and highlight the function of synapsin-Ia/Ib as molecular effector of the behavioral effects of stress.
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Affiliation(s)
- J-M Revest
- INSERM U862, Neurocentre Magendie, Pathophysiology of Addiction group, Bordeaux, France.
| | - N Kaouane
- Université de Bordeaux, Bordeaux, France,CNRS UMR5228, Cognitive and Integrative Neurosciences, Talence, France
| | - M Mondin
- Université de Bordeaux, Bordeaux, France,CNRS UMR 5091, Cellular Physiology of the Synapse, Bordeaux, France
| | - A Le Roux
- INSERM U862, Neurocentre Magendie, Pathophysiology of Addiction group, Bordeaux, France,Université de Bordeaux, Bordeaux, France
| | - F Rougé-Pont
- INSERM U862, Neurocentre Magendie, Pathophysiology of Addiction group, Bordeaux, France,Université de Bordeaux, Bordeaux, France
| | - M Vallée
- INSERM U862, Neurocentre Magendie, Pathophysiology of Addiction group, Bordeaux, France,Université de Bordeaux, Bordeaux, France
| | - J Barik
- CNRS FRE2401, Molecular Genetics, Neurophysiology and Behavior, Institute of Biology, Paris, France
| | - F Tronche
- CNRS FRE2401, Molecular Genetics, Neurophysiology and Behavior, Institute of Biology, Paris, France
| | - A Desmedt
- Université de Bordeaux, Bordeaux, France,CNRS UMR5228, Cognitive and Integrative Neurosciences, Talence, France
| | - P V Piazza
- INSERM U862, Neurocentre Magendie, Pathophysiology of Addiction group, Bordeaux, France,Université de Bordeaux, Bordeaux, France,Department of Pathophysiology, Université de Bordeaux, INSERM U862, Bordeaux F33077, France. E-mail: or
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8
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Murrey HE, Ficarro SB, Krishnamurthy C, Domino SE, Peters EC, Hsieh-Wilson LC. Identification of the plasticity-relevant fucose-alpha(1-2)-galactose proteome from the mouse olfactory bulb. Biochemistry 2009; 48:7261-70. [PMID: 19527073 PMCID: PMC2717711 DOI: 10.1021/bi900640x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 06/15/2009] [Indexed: 01/29/2023]
Abstract
Fucose-alpha(1-2)-galactose [Fucalpha(1-2)Gal] sugars have been implicated in the molecular mechanisms that underlie neuronal development, learning, and memory. However, an understanding of their precise roles has been hampered by a lack of information regarding Fucalpha(1-2)Gal glycoproteins. Here, we report the first proteomic studies of this plasticity-relevant epitope. We identify five classes of putative Fucalpha(1-2)Gal glycoproteins: cell adhesion molecules, ion channels and solute carriers/transporters, ATP-binding proteins, synaptic vesicle-associated proteins, and mitochondrial proteins. In addition, we show that Fucalpha(1-2)Gal glycoproteins are enriched in the developing mouse olfactory bulb (OB) and exhibit a distinct spatiotemporal expression that is consistent with the presence of a "glycocode" to help direct olfactory sensory neuron (OSN) axonal pathfinding. We find that expression of Fucalpha(1-2)Gal sugars in the OB is regulated by the alpha(1-2)fucosyltransferase FUT1. FUT1-deficient mice exhibit developmental defects, including fewer and smaller glomeruli and a thinner olfactory nerve layer, suggesting that fucosylation contributes to OB development. Our findings significantly expand the number of Fucalpha(1-2)Gal glycoproteins and provide new insights into the molecular mechanisms by which fucosyl sugars contribute to neuronal processes.
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Affiliation(s)
- Heather E. Murrey
- Howard Hughes Medical Institute and Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Scott B. Ficarro
- Genomics Institute of the Novartis Research Foundation, San Diego, California 92121
| | - Chithra Krishnamurthy
- Howard Hughes Medical Institute and Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
| | - Steven E. Domino
- Department of Obstetrics and Gynecology, University of Michigan Medical Center, Ann Arbor, Michigan 48109
| | - Eric C. Peters
- Genomics Institute of the Novartis Research Foundation, San Diego, California 92121
| | - Linda C. Hsieh-Wilson
- Howard Hughes Medical Institute and Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125
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9
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Affiliation(s)
- Heather E. Murrey
- Division of Chemistry and Chemical Engineering and Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California 91125
| | - Linda C. Hsieh-Wilson
- Division of Chemistry and Chemical Engineering and Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California 91125
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10
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St John JA, Claxton C, Robinson MW, Yamamoto F, Domino SE, Key B. Genetic manipulation of blood group carbohydrates alters development and pathfinding of primary sensory axons of the olfactory systems. Dev Biol 2006; 298:470-84. [PMID: 16884711 DOI: 10.1016/j.ydbio.2006.06.052] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Revised: 06/29/2006] [Accepted: 06/30/2006] [Indexed: 11/21/2022]
Abstract
Primary sensory neurons in the vertebrate olfactory systems are characterised by the differential expression of distinct cell surface carbohydrates. We show here that the histo-blood group H carbohydrate is expressed by primary sensory neurons in both the main and accessory olfactory systems while the blood group A carbohydrate is expressed by a subset of vomeronasal neurons in the developing accessory olfactory system. We have used both loss-of-function and gain-of-function approaches to manipulate expression of these carbohydrates in the olfactory system. In null mutant mice lacking the alpha(1,2)fucosyltransferase FUT1, the absence of blood group H carbohydrate resulted in the delayed maturation of the glomerular layer of the main olfactory bulb. In addition, ubiquitous expression of blood group A on olfactory axons in gain-of-function transgenic mice caused mis-routing of axons in the glomerular layer of the main olfactory bulb and led to exuberant growth of vomeronasal axons in the accessory olfactory bulb. These results provide in vivo evidence for a role of specific cell surface carbohydrates during development of the olfactory nerve pathways.
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Affiliation(s)
- James A St John
- Brain Growth and Regeneration Laboratory, School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Queensland, Australia
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11
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Murrey HE, Gama CI, Kalovidouris SA, Luo WI, Driggers EM, Porton B, Hsieh-Wilson LC. Protein fucosylation regulates synapsin Ia/Ib expression and neuronal morphology in primary hippocampal neurons. Proc Natl Acad Sci U S A 2005; 103:21-6. [PMID: 16373512 PMCID: PMC1324972 DOI: 10.1073/pnas.0503381102] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although fucose-alpha(1-2)-galactose [Fucalpha(1-2)Gal] carbohydrates have been implicated in cognitive processes such as long-term memory, the molecular mechanisms by which these sugars influence neuronal communication are not well understood. Here, we present molecular insights into the functions of Fucalpha(1-2)Gal sugars, demonstrating that they play a role in the regulation of synaptic proteins and neuronal morphology. We show that synapsins Ia and Ib, synapse-specific proteins involved in neurotransmitter release and synaptogenesis, are the major Fucalpha(1-2)Gal glycoproteins in mature cultured neurons and the adult rat hippocampus. Fucosylation has profound effects on the expression and turnover of synapsin in cells and protects synapsin from degradation by the calcium-activated protease calpain. Our studies suggest that defucosylation of synapsin has critical consequences for neuronal growth and morphology, leading to stunted neurite outgrowth and delayed synapse formation. We also demonstrate that Fucalpha(1-2)Gal carbohydrates are not limited to synapsin but are found on additional glycoproteins involved in modulating neuronal architecture. Together, our studies identify important roles for Fucalpha(1-2)Gal sugars in the regulation of neuronal proteins and morphological changes that may underlie synaptic plasticity.
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Affiliation(s)
- Heather E Murrey
- Howard Hughes Medical Institute and Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
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Baldi E, Bucherelli C. The inverted "u-shaped" dose-effect relationships in learning and memory: modulation of arousal and consolidation. NONLINEARITY IN BIOLOGY, TOXICOLOGY, MEDICINE 2005; 3:9-21. [PMID: 19330154 PMCID: PMC2657842 DOI: 10.2201/nonlin.003.01.002] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In the ample field of biological non-linear relationships there is also the inverted U-shaped dose-effect. In relation to cognitive functions, this phenomenon has been widely reported for many active compounds, in several learning paradigms, in several animal species and does not depend on either administration route (systemic or endocerebral) or administration time (before or after training). This review summarizes its most interesting aspects. The hypothesized mechanisms supporting it are reported and discussed, with particular emphasis on the participation of emotional arousal levels in the modulation of memory processes. Findings on the well documented relationship between stress, emotional arousal, peripheral epinephrine levels, cerebral norepinephrine levels and memory consolidation are reported. These are discussed and the need for further research is underlined.
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Affiliation(s)
- Elisabetta Baldi
- Department of Physiological Sciences, University of Florence, Viale G.B. Morgani 63, I-50134, Firenze, Italy
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Sacchetti B, Lorenzini CA, Baldi E, Bucherelli C, Roberto M, Tassoni G, Brunelli M. Pituitary adenylate cyclase-activating polypeptide hormone (PACAP) at very low dosages improves memory in the rat. Neurobiol Learn Mem 2001; 76:1-6. [PMID: 11525248 DOI: 10.1006/nlme.2001.4014] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To ascertain whether very low dosages of pituitary adenylate cyclase-activating polypeptide (PACAP) influence learning in mammals, immediately after the acquisition trial of a passive avoidance response (PAR) paradigm, PACAP-38 was administered intracerebroventricularly at increasing dosages (0, 0.02, 0.2, 2, 20, and 200 ng in 10 microl saline) to different groups of rats. The mnemonic effects were measured by means of retention testing 48 and 96 h later. At intermediate PACAP-38 concentrations there was a significant mnemonic improvement of the PAR. The maximal effect was observed after the 0.2-ng PACAP-38 administration (longer step-through latencies). There was a lesser effect at the subsequent higher concentration, 2 ng. Higher dosages had no effects. It is concluded that PACAP-38 acts as an enhancer of mammalian mnemonic processes even at very low dosages. The positive effect follows an inverted U-shaped dose-response curve. The results may be of interest for the therapy of some neuropathological conditions.
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Affiliation(s)
- B Sacchetti
- Department of Physiological Sciences, University of Florence, Italy
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Rauca C, Jantze H, Krug M. Does fucose or piracetam modify the effect of hypoxia preconditioning against pentylenetetrazol-induced seizures? Brain Res 2000; 880:187-90. [PMID: 11033005 DOI: 10.1016/s0006-8993(00)02743-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To clarify the question whether the duration of hypoxia exposure has an influence on the point in time or the strength of hypoxic preconditioning, hypoxia exposure of rats lasting 1 and 8 h was tested regarding the modification of susceptibility to acute pentylenetetrazol-induced seizures. Following the short-lasting (1 h) hypoxia, the maximum level of preconditioning action was observed 7 days after hypoxia, whereas the longer-lasting hypoxia (8 h) produced the maximum level of protection 14 days after hypoxia. We investigated the influence of fucose and piracetam on the effect of hypoxia preconditioning by the application of the substances 20 min before the beginning of hypoxia exposure. Fucose did not modify the result of hypoxia preconditioning. But after the treatment with piracetam, the preconditioning effect was prevented following hypoxia lasting 1 and 8 h. We suggest that the radical scavenger properties of piracetam are responsible for the absence of protection against pentylenetetrazol-evoked seizures.
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Affiliation(s)
- C Rauca
- Department of Pharmacology and Toxicology, Faculty of Medicine, Otto-von-Guericke University Magdeburg, Leipziger Str. 44, 39120, Magdeburg, Germany.
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