α-synuclein aggregation and Ser-129 phosphorylation-dependent cell death in oligodendroglial cells

Christine L. Kragh, Louise B. Lund, Fabia Febbraro, Hansen D. Hansen, Gai Wei-Ping, Omar Ali El-Agnaf, Christiane Richter-Landsberg, Poul Henning Jensen

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Abstract

Multiple system atrophy is a neurodegenerative disorder characterized by accumulation of aggregated Ser-129-phosphorylated α-synuclein in oligodendrocytes. p25α is an oligodendroglial protein that potently stimulates α-synuclein aggregation in vitro. To model multiple system atrophy, we coexpressed human p25α and α-synuclein in the rat oligodendroglial cell line OLN-93 and observed a cellular response characterized by a fast retraction of microtubules from the cellular processes to the perinuclear region followed by a protracted development of apoptosis. This response was dependent on phosphorylation at Ser-129 in α-synuclein as demonstrated by site-directed mutagenesis. Treatment of the cells with the kinase inhibitor 2-dimethylamino-4,5,6,7-tetrabromo-1H benzimidazole that targets kinases like casein kinase 2, and polo-like kinases abrogated the toxicity. The polo-like kinase inhibitor BI 2536 caused apoptosis in the model. Ser-129 phosphorylation was linked to the formation of phosphorylated oligomers detectable by immunoblotting, and their formation was inhibited by 2-dimethylamino-4,5,6,7-tetrabromo-1H benzimidazole. The process of microtubule retraction was also dependent on aggregation as demonstrated by the protective effect of treating the cells with the specific peptide inhibitor of α-synuclein aggregation ASI1D and the non-selective inhibitors Congo Red and baicalein. The fast microtubule retraction was followed by the development of the apoptotic markers: activated caspase-3, phosphatidylserine externalization, nuclear condensation, and fragmentation. These markers could all be blocked by the inhibitors of phosphorylation, aggregation, and caspase-3. Hence, the model predicts that both Ser-129 phosphorylation and aggregation control the toxic α-syn pathway in oligodendroglial cells and may represent therapeutic intervention points in multiple system atrophy.

Original languageEnglish
Pages (from-to)10211-10222
Number of pages12
JournalJournal of Biological Chemistry
Volume284
Issue number15
DOIs
Publication statusPublished - 10 Apr 2009
Externally publishedYes

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ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

Cite this

Kragh, C. L., Lund, L. B., Febbraro, F., Hansen, H. D., Wei-Ping, G., Ali El-Agnaf, O., Richter-Landsberg, C., & Jensen, P. H. (2009). α-synuclein aggregation and Ser-129 phosphorylation-dependent cell death in oligodendroglial cells. Journal of Biological Chemistry, 284(15), 10211-10222. https://doi.org/10.1074/jbc.M809671200