The extent of synaptic stripping of motoneurons after axotomy is not correlated to activation of surrounding glia or downregulation of postsynaptic adhesion molecules.

Synapse elimination in the adult central nervous system can be modelled by axotomy of spinal motoneurons which triggers removal of synapses from the cell surface of lesioned motoneurons by processes that remain elusive. Proposed candidate mechanisms are removal of synapses by reactive microglia and...

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Main Authors: Alexander Berg, Johan Zelano, Sebastian Thams, Staffan Cullheim
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2013-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3602371?pdf=render
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author Alexander Berg
Johan Zelano
Sebastian Thams
Staffan Cullheim
author_facet Alexander Berg
Johan Zelano
Sebastian Thams
Staffan Cullheim
author_sort Alexander Berg
collection DOAJ
description Synapse elimination in the adult central nervous system can be modelled by axotomy of spinal motoneurons which triggers removal of synapses from the cell surface of lesioned motoneurons by processes that remain elusive. Proposed candidate mechanisms are removal of synapses by reactive microglia and astrocytes, based on the remarkable activation of these cell types in the vicinity of motoneurons following axon lesion, and/or decreased expression of synaptic adhesion molecules in lesioned motoneurons. In the present study, we investigated glia activation and adhesion molecule expression in motoneurons in two mouse strains with deviant patterns of synapse elimination following axotomy. Mice deficient in complement protein C3 display a markedly reduced loss of synapses from axotomized motoneurons, whereas mice with impaired function of major histocompatibility complex (MHC) class Ia display an augmented degree of stripping after axotomy. Activation of microglia and astrocytes was assessed by semiquantative immunohistochemistry for Iba 1 (microglia) and GFAP (astrocytes), while expression of synaptic adhesion molecules was determined by in situ hybridization. In spite of the fact that the two mouse strains display very different degrees of synapse elimination, no differences in terms of glial activation or in the downregulation of the studied adhesion molecules (SynCAM1, neuroligin-2,-3 and netrin G-2 ligand) could be detected. We conclude that neither glia activation nor downregulation of synaptic adhesion molecules are correlated to the different extent of the synaptic stripping in the two studied strains. Instead the magnitude of the stripping event is most likely a consequence of a precise molecular signaling, which at least in part is mediated by immune molecules.
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spelling doaj.art-c8864efd423c478fb4b089225dc7bb522022-12-21T17:31:41ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-0183e5964710.1371/journal.pone.0059647The extent of synaptic stripping of motoneurons after axotomy is not correlated to activation of surrounding glia or downregulation of postsynaptic adhesion molecules.Alexander BergJohan ZelanoSebastian ThamsStaffan CullheimSynapse elimination in the adult central nervous system can be modelled by axotomy of spinal motoneurons which triggers removal of synapses from the cell surface of lesioned motoneurons by processes that remain elusive. Proposed candidate mechanisms are removal of synapses by reactive microglia and astrocytes, based on the remarkable activation of these cell types in the vicinity of motoneurons following axon lesion, and/or decreased expression of synaptic adhesion molecules in lesioned motoneurons. In the present study, we investigated glia activation and adhesion molecule expression in motoneurons in two mouse strains with deviant patterns of synapse elimination following axotomy. Mice deficient in complement protein C3 display a markedly reduced loss of synapses from axotomized motoneurons, whereas mice with impaired function of major histocompatibility complex (MHC) class Ia display an augmented degree of stripping after axotomy. Activation of microglia and astrocytes was assessed by semiquantative immunohistochemistry for Iba 1 (microglia) and GFAP (astrocytes), while expression of synaptic adhesion molecules was determined by in situ hybridization. In spite of the fact that the two mouse strains display very different degrees of synapse elimination, no differences in terms of glial activation or in the downregulation of the studied adhesion molecules (SynCAM1, neuroligin-2,-3 and netrin G-2 ligand) could be detected. We conclude that neither glia activation nor downregulation of synaptic adhesion molecules are correlated to the different extent of the synaptic stripping in the two studied strains. Instead the magnitude of the stripping event is most likely a consequence of a precise molecular signaling, which at least in part is mediated by immune molecules.http://europepmc.org/articles/PMC3602371?pdf=render
spellingShingle Alexander Berg
Johan Zelano
Sebastian Thams
Staffan Cullheim
The extent of synaptic stripping of motoneurons after axotomy is not correlated to activation of surrounding glia or downregulation of postsynaptic adhesion molecules.
PLoS ONE
title The extent of synaptic stripping of motoneurons after axotomy is not correlated to activation of surrounding glia or downregulation of postsynaptic adhesion molecules.
title_full The extent of synaptic stripping of motoneurons after axotomy is not correlated to activation of surrounding glia or downregulation of postsynaptic adhesion molecules.
title_fullStr The extent of synaptic stripping of motoneurons after axotomy is not correlated to activation of surrounding glia or downregulation of postsynaptic adhesion molecules.
title_full_unstemmed The extent of synaptic stripping of motoneurons after axotomy is not correlated to activation of surrounding glia or downregulation of postsynaptic adhesion molecules.
title_short The extent of synaptic stripping of motoneurons after axotomy is not correlated to activation of surrounding glia or downregulation of postsynaptic adhesion molecules.
title_sort extent of synaptic stripping of motoneurons after axotomy is not correlated to activation of surrounding glia or downregulation of postsynaptic adhesion molecules
url http://europepmc.org/articles/PMC3602371?pdf=render
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