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Neuronal and glial expression of the adhesion molecule TAG-1 is regulated after peripheral nerve lesion or central neurodegeneration of adult nervous system

Authors

  • Sylvia Soares,

    1. Laboratoire de Neurobiologie des Signaux Intercellulaires, UMR7101, CNRS-UPMC, Case 02, Bat. A, 3èmeétage, 7 Quai Saint Bernard, 75005 Paris, France
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    • S.S and M.T. contributed equally to this work.

  • Maria Traka,

    1. Department of Basic Science, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Crete, Greece
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    • *

      Present address: Department of Neurology, University of Chicago, 5841 South Maryland Ave., MC2030, Chicago, IL., USA

    • S.S and M.T. contributed equally to this work.

  • Ysander Von Boxberg,

    1. Laboratoire de Neurobiologie des Signaux Intercellulaires, UMR7101, CNRS-UPMC, Case 02, Bat. A, 3èmeétage, 7 Quai Saint Bernard, 75005 Paris, France
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  • Céline Bouquet,

    1. Laboratoire de Neurobiologie des Signaux Intercellulaires, UMR7101, CNRS-UPMC, Case 02, Bat. A, 3èmeétage, 7 Quai Saint Bernard, 75005 Paris, France
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  • Domna Karagogeos,

    1. Department of Basic Science, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Crete, Greece
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  • Fatiha Nothias

    1. Laboratoire de Neurobiologie des Signaux Intercellulaires, UMR7101, CNRS-UPMC, Case 02, Bat. A, 3èmeétage, 7 Quai Saint Bernard, 75005 Paris, France
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Dr Fatiha Nothias, as above.
E-mail: fatiha.nothias@snv.jussieu.fr

Abstract

Expression of the cell adhesion molecule TAG-1 is down-regulated in adult brain, with the exception of certain areas exhibiting structural plasticity. Here, we present evidence that TAG-1 expression persists also in adult rat spinal cord and dorsal root ganglia (DRG), and can be up-regulated after injury. On Western blots of adult tissue, TAG-1 is detected as a 135-kDa band, with an additional specific 90-kDa band, not present in developing tissue. TAG-1 expression is found both in DRG neurons and in Schwann cells, particularly those associated with the peripherally projecting DRG processes. Quantitative in situ hybridization revealed that TAG-1 expression is significantly higher in small neurons that give rise to unmyelinated fibers, than in large DRG neurons. The regulation of TAG-1 was then examined in two different lesion paradigms. After a sciatic nerve lesion, TAG-1 expression is not up-regulated in DRG neurons, but decreases with time. At the lesion site, reactive Schwann cells up-regulate TAG-1, as demonstrated by both immunohistochemistry and in situ hybridization. In a second paradigm, we injected kainic acid into the spinal cord that kills neurons but spares glia and axons. TAG-1 is up-regulated in the spinal neuron-depleted area as well as in the corresponding dorsal and ventral roots, associated with both target-deprived afferent fibers and with the non-neuronal cells that invade the lesion site. These results demonstrate a local up-regulation of TAG-1 in the adult that is induced in response to injury, suggesting its involvement in axonal re-modelling, neuron–glia interactions, and glial cell migration.

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