Evidence for synaptic stripping by cortical microglia
Article first published online: 29 NOV 2006
Copyright © 2006 Wiley-Liss, Inc.
Volume 55, Issue 4, pages 360–368, March 2007
How to Cite
Trapp, B. D., Wujek, J. R., Criste, G. A., Jalabi, W., Yin, X., Kidd, G. J., Stohlman, S. and Ransohoff, R. (2007), Evidence for synaptic stripping by cortical microglia. Glia, 55: 360–368. doi: 10.1002/glia.20462
- Issue published online: 11 JAN 2007
- Article first published online: 29 NOV 2006
- Manuscript Accepted: 23 OCT 2006
- Manuscript Revised: 20 SEP 2006
- Manuscript Received: 3 JUL 2006
- National Institutes of Health. Grant Numbers: NS 38667, NS 32151
- microglial activation;
- chemokine CCL2;
- immune privilege
Recent studies have described significant demyelination and microglial activation in the cerebral cortex of brains from multiple sclerosis patients. To date, however, experimental models of cortical demyelination or cortical inflammation have not been extensively studied. In this report we describe focal cortical inflammation induced by stereotaxic injection of killed bacteria (BCG), followed 1 month later by subcutaneous injection of the same antigen, a protocol that overcomes the immune privilege of the cortex. Intracerebral BCG injection produced focal microglial activation at the injection site (termed acute lesion). Ten days after peripheral challenge (termed immune-mediated lesion), larger areas and higher densities of activated microglia were found near the injection site. In both paradigms, activated microglia and/or their processes closely apposed neuronal perikarya and apical dendrites. In the immune-mediated lesions, ∼45% of the axosomatic synapses was displaced by activated microglia. Upon activation, therefore, cortical microglial migrate to and strip synapses from neuronal perikarya. Since neuronal pathology was not a feature of either the acute or immune-mediated lesion, synaptic stripping by activated microglia may have neuroprotective consequences. © 2006 Wiley-Liss, Inc.