Browsing by Author "Thomas, Craig J."

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    Caspase-1 causes truncation and aggregation of the Parkinson's disease-associated protein α-synuclein
    (National Academy of Sciences, 2016-08-23) Wang, Wei; Nguyen, Linh T. T.; Burlak, Christopher; Chegini, Fariba; Guo, Feng; Chataway, Tim; Ju, Shulin; Fisher, Oriana S.; Miller, David W.; Datta, Debajyoti; Wu, Fang; Wu, Chun-Xiang; Landeru, Anuradha; Wells, James A.; Cookson, Mark R.; Boxer, Matthew B.; Thomas, Craig J.; Gai, Wei Ping; Ringe, Dagmar; Petsko, Gregory A.; Hoang, Quyen Q.; Department of Biochemistry & Molecular Biology, IU School of Medicine
    The aggregation of α-synuclein (aSyn) leading to the formation of Lewy bodies is the defining pathological hallmark of Parkinson's disease (PD). Rare familial PD-associated mutations in aSyn render it aggregation-prone; however, PD patients carrying wild type (WT) aSyn also have aggregated aSyn in Lewy bodies. The mechanisms by which WT aSyn aggregates are unclear. Here, we report that inflammation can play a role in causing the aggregation of WT aSyn. We show that activation of the inflammasome with known stimuli results in the aggregation of aSyn in a neuronal cell model of PD. The insoluble aggregates are enriched with truncated aSyn as found in Lewy bodies of the PD brain. Inhibition of the inflammasome enzyme caspase-1 by chemical inhibition or genetic knockdown with shRNA abated aSyn truncation. In vitro characterization confirmed that caspase-1 directly cleaves aSyn, generating a highly aggregation-prone species. The truncation-induced aggregation of aSyn is toxic to neuronal culture, and inhibition of caspase-1 by shRNA or a specific chemical inhibitor improved the survival of a neuronal PD cell model. This study provides a molecular link for the role of inflammation in aSyn aggregation, and perhaps in the pathogenesis of sporadic PD as well.