Amyloid fibrils are the molecular trigger of inflammation in Parkinson's disease.
Parkinson's disease (PD) is an age-related movement disorder characterized by a progressive degeneration of dopaminergic neurons in the midbrain. Although the presence of amyloid deposits of α-synuclein (α-syn) is the main pathological feature, PD brains also present a severe permanent inflammation, which largely contributes to neuropathology. Although α-syn has recently been implicated in this process, the molecular mechanisms underlying neuroinflammation remain unknown. In the present study, we investigated the ability of different α-syn aggregates to trigger inflammatory responses. We showed that α-syn induced inflammation through activation of Toll-like receptor 2 (TLR2) and the nucleotide oligomerization domain-like receptor pyrin domain containing 3 (NLRP3) inflammasome only when folded as amyloid fibrils. Oligomeric species, thought to be the primary species responsible for the disease, were surprisingly unable to trigger the same cascades. As neuroinflammation is a key player in PD pathology, these results put fibrils back to the fore and rekindles discussions about the primary toxic species contributing to the disease. Our data also suggest that the inflammatory properties of α-syn fibrils are linked to their intrinsic structure, most probably to their cross-β structure. Since fibrils of other amyloids induce similar immunological responses, we propose that the canonical fibril-specific cross-β structure represents a new generic motif recognized by the innate immune system.
Laboratory of Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels 1050, Belgium agustot@ulb.ac.be adelingustot@hotmail.com.
Adelin
A
Gustot
Departamento de Química Biológica, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC, CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina.
José Ignacio
JI
Gallea
Laboratory of Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels 1050, Belgium.
Rabia
R
Sarroukh
Departamento de Química Biológica, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC, CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, X5000HUA Córdoba, Argentina.
María Soledad
MS
Celej
Laboratory of Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels 1050, Belgium.
Jean-Marie
JM
Ruysschaert
Laboratory of Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels 1050, Belgium.
Vincent
V
Raussens
D000682:Amyloid / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D007113:Immunity, Innate / Q000235:genetics; D058847:Inflammasomes / Q000378:metabolism; D007249:Inflammation / Q000378:metabolism* / Q000473:pathology; D053583:Interleukin-1beta / Q000378:metabolism; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D010300:Parkinson Disease / Q000378:metabolism* / Q000473:pathology; D066263:Protein Aggregation, Pathological; D017433:Protein Structure, Secondary / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics; D051195:Toll-Like Receptor 2 / Q000737:chemistry / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D051844:alpha-Synuclein / Q000737:chemistry / Q000378:metabolism*
D000682:Amyloid; D002352:Carrier Proteins; D058847:Inflammasomes; D053583:Interleukin-1beta; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C453881:NLRP3 protein, human; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2; D014409:Tumor Necrosis Factor-alpha; D051844:alpha-Synuclein
amyloid fibril; cross-β structure; nucleotide oligomerization domain-like receptor pyrin domain containing 3 (NLRP3) inflammasome; oligomer; structure-inflammatory properties relationship; α-synuclein