Altered ceramide metabolism is a feature in the extracellular vesicle mediated spread of alpha-synuclein in sporadic and GBA-linked Lewy body disease
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ABSTRACT: Mutations in glucocerebrosidase (GBA) are the most prevalent genetic risk factor for Lewy body disorders (LBD) – collectively Parkinson’s disease, Parkinson’s disease dementia and dementia with Lewy bodies. Despite this genetic association, it remains unclear how GBA mutation contributes to the susceptibility of developing LBD. We investigated relationships between LBD-specific glucocerebrosidase deficits, GBA-related pathways, and α-synuclein levels in post-mortem brain tissue from LBD and controls with and without GBA mutations. Our study shows that LBD brains, regardless of GBA mutations, are characterised by altered sphingolipid metabolism, with prominent changes in ceramide species. Since extracellular vesicles (EV) could be involved in LBD pathogenesis by spreading disease linked lipids and proteins, we investigated EV derived from post-mortem cerebrospinal fluid (CSF) and brain tissue from GBA mutation carriers and non-carriers. EV purified from LBD post-mortem CSF and frontal cortex are heavily loaded with ceramides and neurodegeneration-linked proteins including alpha-synuclein and amyloid precursor protein. Our in vitro studies demonstrate that LBD EV constitute a “pathological package” capable of inducing aggregation of wild type alpha-synuclein, potentially through a combination of alpha-synuclein-ceramide interaction and the presence of pathological forms of alpha-synuclein. Together our findings indicate that abnormalities in ceramide metabolism are a feature of LBD, constituting a promising source of biomarkers. GBA mutation likely accelerates the pathological process occurring in sporadic LBD, probably through endolysosomal deficiency, but does not induce alpha-synucleinopathy since healthy normal GBA mutation carriers without alpha-synuclein pathology occur.
INSTRUMENT(S): Q Exactive HF
ORGANISM(S): Homo Sapiens (human)
TISSUE(S): Frontal Lobe
DISEASE(S): Lewy Body Dementia
SUBMITTER: Ivo Fabrik
LAB HEAD: Matthias Trost
PROVIDER: PXD026980 | Pride | 2021-11-02
REPOSITORIES: Pride
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