Neuron-specific proteotoxicity of mutant ataxin-3 in C. elegans: rescue by the DAF-16 and HSF-1 pathways

• Published in: Human molecular genetics 2011-08, Vol.20 (15), p.2996-3009
• Main Authors: Teixeira-Castro, Andreia, Ailion, Michael, Jalles, Ana, Brignull, Heather R., Vilaça, João L., Dias, Nuno, Rodrigues, Pedro, Oliveira, João F., Neves-Carvalho, Andreia, Morimoto, Richard I., Maciel, Patrícia
• Format: Article
• Language: English
• Subjects: Animals; Ataxin-3; Biological and medical sciences; Caenorhabditis elegans; Caenorhabditis elegans - genetics; Caenorhabditis elegans - metabolism; Caenorhabditis elegans Proteins - genetics; Caenorhabditis elegans Proteins - metabolism; Cell Aggregation - genetics; Cell Aggregation - physiology; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Forkhead Transcription Factors; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; Medical sciences; Microscopy, Confocal; Molecular and cellular biology; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; Neurology; Neurons - cytology; Neurons - metabolism; Neurons - pathology; Peptides - metabolism; Transcription Factors - genetics; Transcription Factors - metabolism
• ISSN: 0964-6906; 1460-2083
• DOI: 10.1093/hmg/ddr203

The risk of developing neurodegenerative diseases increases with age. Although many of the molecular pathways regulating proteotoxic stress and longevity are well characterized, their contribution to disease susceptibility remains unclear. In this study, we describe a new Caenorhabditis elegans model of Machado-Joseph disease pathogenesis. Pan-neuronal expression of mutant ATXN3 leads to a polyQ-length dependent, neuron subtype-specific aggregation and neuronal dysfunction. Analysis of different neurons revealed a pattern of dorsal nerve cord and sensory neuron susceptibility to mutant ataxin-3 that was distinct from the aggregation and toxicity profiles of polyQ-alone proteins. This reveals that the sequences flanking the polyQ-stretch in ATXN3 have a dominant influence on cell-intrinsic neuronal factors that modulate polyQ-mediated pathogenesis. Aging influences the ATXN3 phenotypes which can be suppressed by the downregulation of the insulin/insulin growth factor-1-like signaling pathway and activation of heat shock factor-1.