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In vivo suppression of polyglutamine neurotoxicity by C-terminus of Hsp70-interacting protein (CHIP) supports an aggregation model of pathogenesis
Journal article   Open access   Peer reviewed

In vivo suppression of polyglutamine neurotoxicity by C-terminus of Hsp70-interacting protein (CHIP) supports an aggregation model of pathogenesis

Aislinn J Williams, Tina M Knutson, Veronica F Colomer Gould and Henry L Paulson
Neurobiology of disease, Vol.33(3), pp.342-353
03/2009
DOI: 10.1016/j.nbd.2008.10.016
PMCID: PMC2662361
PMID: 19084066
url
https://doaj.org/article/da09d05a8a9f4dc6ba688181f9679a50View
Open Access

Abstract

Perturbations in neuronal protein homeostasis likely contribute to disease pathogenesis in polyglutamine (polyQ) neurodegenerative disorders. Here we provide evidence that the co-chaperone and ubiquitin ligase, CHIP (C-terminus of Hsp70-interacting protein), is a central component to the homeostatic mechanisms countering toxic polyQ proteins in the brain. Genetic reduction or elimination of CHIP accelerates disease in transgenic mice expressing polyQ-expanded ataxin-3, the disease protein in Spinocerebellar Ataxia Type 3 (SCA3). In parallel, CHIP reduction markedly increases the level of ataxin-3 microaggregates, which partition in the soluble fraction of brain lysates yet are resistant to dissociation with denaturing detergent, and which precede the appearance of inclusions. The level of microaggregates in the CNS, but not of ataxin-3 monomer, correlates with disease severity. Additional cell-based studies suggest that either of two quality control ubiquitin ligases, CHIP or E4B, can reduce steady state levels of expanded, but not wild-type, ataxin-3. Our results support an aggregation model of polyQ disease pathogenesis in which ataxin-3 microaggregates are a neurotoxic species, and suggest that enhancing CHIP activity is a possible route to therapy for SCA3 and other polyQ diseases.
Aging Peptides Ataxin-3 Machado-Joseph Disease - metabolism Humans Motor Activity Brain - metabolism Nerve Tissue Proteins - chemistry Neurons - metabolism Nuclear Proteins - genetics Repressor Proteins - metabolism Machado-Joseph Disease - pathology Repressor Proteins - chemistry Heat-Shock Proteins - metabolism Ubiquitin-Protein Ligases - metabolism Repressor Proteins - genetics Mice, Transgenic Nuclear Proteins - metabolism Inclusion Bodies - physiology Nuclear Proteins - chemistry Nerve Tissue Proteins - genetics Nerve Tissue Proteins - metabolism Animals Brain - pathology Cell Line, Tumor Machado-Joseph Disease - physiopathology Protein Binding Mice Ubiquitin-Protein Ligases - genetics Machado-Joseph Disease - genetics

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