Vertebrate food products as a potential source of prion-like α-synuclein - PubMed

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The aberrant aggregation of the protein α-synuclein is thought to be involved in Parkinson's disease (PD). However, the factors that lead to initiation and propagation of α-synuclein aggregation are not clearly understood. Recently, the hypothesis that α-synuclein aggregation spreads via a prion-like mechanism originating in the gut has gained much scientific attention. If α-synuclein spreads via a prion-like mechanism, then an important question becomes, what are the origins of this prion-like species? Here we review the possibility that α-synuclein aggregation could be seeded via the ingestion of a prion-like α-synuclein species contained within food products originating from vertebrates. To do this, we highlight current evidence for the gut-to-brain hypothesis of PD, and put this in context of available routes of α-synuclein prion infectivity via the gastrointestinal (GI) tract. We then discuss meat as a ready exogenous source of α-synuclein and how certain risk factors, including inflammation, may allow for dietary α-synuclein to pass from the GI lumen into the host to induce pathology. Lastly, we review epidemiological evidence that dietary factors may be involved in PD. Overall, research to date has yet to directly test the contribution of dietary α-synuclein to the mechanism of initiation and progression of the disease. However, numerous experimental findings, including the potent seeding and spreading behavior of α-synuclein fibrils, seem to support, at least in part, the feasibility of an infection with a prion α-synuclein particle via the GI tract. Further studies are required to determine whether dietary α-synuclein contributes to seeding pathology in the gut.

Summary
The aggregation of α-synuclein protein is implicated in Parkinson's disease (PD), yet the factors driving this process remain unclear. Recent research suggests that α-synuclein may spread through a prion-like mechanism originating in the gut. This article explores the hypothesis that α-synuclein aggregation could be initiated by ingesting prion-like α-synuclein from vertebrate food products. It reviews evidence supporting the gut-to-brain hypothesis of PD and examines how dietary α-synuclein could enter the body, particularly through the gastrointestinal (GI) tract, especially under conditions of inflammation. The article also discusses meat as a potential source of exogenous α-synuclein and highlights epidemiological data linking dietary factors to PD. Although current research has not definitively tested the role of dietary α-synuclein in the disease's initiation and progression, experimental findings indicate that α-synuclein fibrils exhibit strong seeding and spreading capabilities. This suggests the possibility of infection via prion-like α-synuclein particles through the GI tract. Further research is necessary to clarify whether dietary α-synuclein plays a role in seeding pathology in the gut.