CHMP2B mutants linked to frontotemporal dementia impair maturation of dendritic spines.

Abstract

The highly conserved ESCRT-III complex is responsible for deformation and cleavage of membranes during endosomal trafficking and other cellular activities. In humans, dominant mutations in the ESCRT-III subunit CHMP2B cause frontotemporal dementia (FTD). The decade-long process leading to this cortical degeneration is not well understood. One possibility is that, akin to other neurodegenerative diseases, the pathogenic protein affects the integrity of dendritic spines and synapses before any neuronal death. Using confocal microscopy and 3D reconstruction, we examined whether expressing the FTD-linked mutants CHMP2B(intron5) and CHMP2B(Delta10) in cultured hippocampal neurons modified the number or structure of spines. Both mutants induced a significant decrease in the proportion of large spines with mushroom morphology, without overt degeneration. Furthermore, CHMP2B(Delta10) induced a drop in frequency and amplitude of spontaneous excitatory postsynaptic currents, suggesting that the more potent synapses were lost. These effects seemed unrelated to changes in autophagy. Depletion of endogenous CHMP2B by RNAi resulted in morphological changes similar to those induced by mutant CHMP2B, consistent with dominant-negative activity of pathogenic mutants. Thus, CHMP2B is required for spine growth. Taken together, these results demonstrate that a mutant ESCRT-III subunit linked to a human neurodegenerative disease can disrupt the normal pattern of spine development.

• Authors: Agnès Belly, Gilles Bodon, Béatrice Blot, Alexandre Bouron, Rémy Sadoul, Yves Goldberg
• Journal: Journal of cell science (J Cell Sci) Vol. 123 Issue Pt 17 Pg. 2943-54 (Sep 01 2010) ISSN: 1477-9137 [Electronic] England
• PMID: 20699355 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• CHMP2B protein, human
• Endosomal Sorting Complexes Required for Transport
• Nerve Tissue Proteins

Topics

• Animals
• Brain (cytology, metabolism)
• Cells, Cultured
• Dendrites (metabolism, pathology)
• Dendritic Spines (genetics, metabolism, pathology)
• Endosomal Sorting Complexes Required for Transport (genetics)
• Frontotemporal Dementia (genetics, metabolism, pathology)
• Humans
• Mutation
• Nerve Tissue Proteins (genetics)
• Rats