Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Excitation-induced ataxin-3 aggregation in neurons from patients with Machado–Joseph disease

Abstract

Machado–Joseph disease (MJD; also called spinocerebellar ataxia type 3) is a dominantly inherited late-onset neurodegenerative disorder caused by expansion of polyglutamine (polyQ)-encoding CAG repeats in the MJD1 gene (also known as ATXN3). Proteolytic liberation of highly aggregation-prone polyQ fragments from the protective sequence of the MJD1 gene product ataxin 3 (ATXN3) has been proposed to trigger the formation of ATXN3-containing aggregates, the neuropathological hallmark of MJD1,2,3,4,5. ATXN3 fragments are detected in brain tissue of MJD patients and transgenic mice expressing mutant human ATXN3(Q71)6, and their amount increases with disease severity, supporting a relationship between ATXN3 processing and disease progression. The formation of early aggregation intermediates is thought to have a critical role in disease initiation7,8, but the precise pathogenic mechanism operating in MJD has remained elusive9. Here we show that l-glutamate-induced excitation of patient-specific induced pluripotent stem cell (iPSC)-derived neurons initiates Ca2+-dependent proteolysis of ATXN3 followed by the formation of SDS-insoluble aggregates. This phenotype could be abolished by calpain inhibition, confirming a key role of this protease in ATXN3 aggregation. Aggregate formation was further dependent on functional Na+ and K+ channels as well as ionotropic and voltage-gated Ca2+ channels, and was not observed in iPSCs, fibroblasts or glia, thereby providing an explanation for the neuron-specific phenotype of this disease. Our data illustrate that iPSCs enable the study of aberrant protein processing associated with late-onset neurodegenerative disorders in patient-specific neurons.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Generation of patient-specific neural cultures.
Figure 2: Excitation induces ATXN3 cleavage and aggregation.
Figure 3: Aggregation of ATXN3 is calpain dependent.
Figure 4: ATXN3 aggregation is neuron specific.

Similar content being viewed by others

References

  1. Berke, S. J., Schmied, F. A., Brunt, E. R., Ellerby, L. M. & Paulson, H. L. Caspase-mediated proteolysis of the polyglutamine disease protein ataxin-3. J. Neurochem. 89, 908–918 (2004)

    Article  CAS  Google Scholar 

  2. Jung, J., Xu, K., Lessing, D. & Bonini, N. M. Preventing ataxin-3 protein cleavage mitigates degeneration in a Drosophila model of SCA3. Hum. Mol. Genet. 18, 4843–4852 (2009)

    Article  CAS  Google Scholar 

  3. Tarlac, V. & Storey, E. Role of proteolysis in polyglutamine disorders. J. Neurosci. Res. 74, 406–416 (2003)

    Article  CAS  Google Scholar 

  4. Wellington, C. L. et al. Caspase cleavage of gene products associated with triplet expansion disorders generates truncated fragments containing the polyglutamine tract. J. Biol. Chem. 273, 9158–9167 (1998)

    Article  CAS  Google Scholar 

  5. Rubinsztein, D. C., Wyttenbach, A. & Rankin, J. Intracellular inclusions, pathological markers in diseases caused by expanded polyglutamine tracts? J. Med. Genet. 36, 265–270 (1999)

    CAS  PubMed  PubMed Central  Google Scholar 

  6. Goti, D. et al. A mutant ataxin-3 putative-cleavage fragment in brains of Machado–Joseph disease patients and transgenic mice is cytotoxic above a critical concentration. J. Neurosci. 24, 10266–10279 (2004)

    Article  CAS  Google Scholar 

  7. Chen, S., Ferrone, F. A. & Wetzel, R. Huntington’s disease age-of-onset linked to polyglutamine aggregation nucleation. Proc. Natl Acad. Sci. USA 99, 11884–11889 (2002)

    Article  ADS  CAS  Google Scholar 

  8. Schaffar, G. et al. Cellular toxicity of polyglutamine expansion proteins: mechanism of transcription factor deactivation. Mol. Cell 15, 95–105 (2004)

    Article  CAS  Google Scholar 

  9. Gatchel, J. R. & Zoghbi, H. Y. Diseases of unstable repeat expansion: mechanisms and common principles. Nature Rev. Genet. 6, 743–755 (2005)

    Article  CAS  Google Scholar 

  10. Williams, A. J. & Paulson, H. L. Polyglutamine neurodegeneration: protein misfolding revisited. Trends Neurosci. 31, 521–528 (2008)

    Article  CAS  Google Scholar 

  11. Berridge, M. J. Neuronal calcium signaling. Neuron 21, 13–26 (1998)

    Article  CAS  Google Scholar 

  12. Koch, P., Opitz, T., Steinbeck, J. A., Ladewig, J. & Brüstle, O. A rosette-type, self-renewing human ES cell-derived neural stem cell with potential for in vitro instruction and synaptic integration. Proc. Natl Acad. Sci. USA 106, 3225–3230 (2009)

    Article  ADS  CAS  Google Scholar 

  13. Thakur, A. K. & Wetzel, R. Mutational analysis of the structural organization of polyglutamine aggregates. Proc. Natl Acad. Sci. USA 99, 17014–17019 (2002)

    Article  ADS  CAS  Google Scholar 

  14. Ikeda, H. et al. Expanded polyglutamine in the Machado–Joseph disease protein induces cell death in vitro and in vivo. Nature Genet. 13, 196–202 (1996)

    Article  MathSciNet  CAS  Google Scholar 

  15. Scherzinger, E. et al. Huntingtin-encoded polyglutamine expansions form amyloid-like protein aggregates in vitro and in vivo. Cell 90, 549–558 (1997)

    Article  CAS  Google Scholar 

  16. Haacke, A. et al. Proteolytic cleavage of polyglutamine-expanded ataxin-3 is critical for aggregation and sequestration of non-expanded ataxin-3. Hum. Mol. Genet. 15, 555–568 (2006)

    Article  CAS  Google Scholar 

  17. Haacke, A., Hartl, F. U. & Breuer, P. Calpain inhibition is sufficient to suppress aggregation of polyglutamine-expanded ataxin-3. J. Biol. Chem. 282, 18851–18856 (2007)

    Article  CAS  Google Scholar 

  18. Uchihara, T. et al. Non-expanded polyglutamine proteins in intranuclear inclusions of hereditary ataxias: triple-labeling immunofluorescence study. Acta Neuropathol. 102, 149–152 (2001)

    CAS  PubMed  Google Scholar 

  19. Hartl, F. U., Bracher, A. & Hayer-Hartl, M. Molecular chaperones in protein folding and proteostasis. Nature 475, 324–332 (2011)

    Article  CAS  Google Scholar 

  20. Yoo, S. Y. et al. SCA7 knockin mice model human SCA7 and reveal gradual accumulation of mutant ataxin-7 in neurons and abnormalities in short-term plasticity. Neuron 37, 383–401 (2003)

    Article  CAS  Google Scholar 

  21. Watase, K. et al. A long CAG repeat in the mouse Sca1 locus replicates SCA1 features and reveals the impact of protein solubility on selective neurodegeneration. Neuron 34, 905–919 (2002)

    Article  CAS  Google Scholar 

  22. Li, M., Chevalier-Larsen, E. S., Merry, D. E. & Diamond, M. I. Soluble androgen receptor oligomers underlie pathology in a mouse model of spinobulbar muscular atrophy. J. Biol. Chem. 282, 3157–3164 (2007)

    Article  CAS  Google Scholar 

  23. Williams, A. J., Knutson, T. M., Colomer Gould, V. F. & Paulson, H. L. In vivo suppression of polyglutamine neurotoxicity by C-terminus of Hsp70-interacting protein (CHIP) supports an aggregation model of pathogenesis. Neurobiol. Dis. 33, 342–353 (2009)

    Article  CAS  Google Scholar 

  24. Takahashi, K. et al. Induction of pluripotent stem cells from adult human fibroblasts by defined factors. Cell 131, 861–872 (2007)

    Article  CAS  Google Scholar 

  25. Hazeki, N., Tukamoto, T., Goto, J. & Kanazawa, I. Formic acid dissolves aggregates of an N-terminal huntingtin fragment containing an expanded polyglutamine tract: applying to quantification of protein components of the aggregates. Biochem. Biophys. Res. Commun. 277, 386–393 (2000)

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We thank S. Auel, D. Kühne, M. Segschneider and V. Dobberahn for technical support, A. Leinhaas for conducting the teratoma assays and H. L. Paulson for providing the polyclonal ATXN3 antibody used for immunocytochemistry. The human embryonic stem cell lines H9 and I3 (used as control for quantitative PCR) and I6 (originally used to derive the lt-NES cells) were provided by J. Itskovitz-Eldor (Technion, Israel Institute of Technology, Haifa, Israel). The work was supported by the German Federal Ministry for Education and Research (BMBF; grants 01GNO813, 01GS0860), the European Union (LSHG-CT-2006-018739, ESTOOLS; HEALTH-F5-2010-266753, SCR&Tox), the Deutsche Forschungsgemeinschaft (WU184/6-1, EV143/1-1), BONFOR and the Hertie Foundation.

Author information

Authors and Affiliations

Authors

Contributions

P.K. and P.B.: conception and study design, directed differentiation of iPSCs, cellular/molecular assays for disease modelling, data assembly, analysis and interpretation, writing of manuscript; M.P. and J.J.: iPSC clone derivation, maintenance and validation, directed differentiation of iPSCs; J.K., D.P., J.D., J.L., J.M., P.H.: data collection, analysis and interpretation; B.O.E., U.W., T.K.: conception, data analysis and interpretation; T.T.: provision of material; O.B.: conception, data analysis and interpretation, writing of manuscript.

Corresponding author

Correspondence to Oliver Brüstle.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Figures

This file contains Supplementary Figures 1-16 with legends. (PDF 12324 kb)

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Cite this article

Koch, P., Breuer, P., Peitz, M. et al. Excitation-induced ataxin-3 aggregation in neurons from patients with Machado–Joseph disease. Nature 480, 543–546 (2011). https://doi.org/10.1038/nature10671

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature10671

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing