Kasen · Neurobiology of disease 2022 · narrative review · n=?

Upregulation of α-synuclein following immune activation: Possible trigger of Parkinson's disease.

Cited 79 times in the scientific literature.

Level 5 - mechanism / opinion, no new human data

Narrative review synthesizing mechanistic literature and proposing a theoretical framework without primary data or systematic search.

PubMed 35143968 · doi:10.1016/j.nbd.2022.105654 · record verified 2026-08-28

What was done

This narrative review synthesized literature on the physiological roles of alpha-synuclein (α-syn)—including its putative functions as an antimicrobial peptide, transcriptional regulator, and immune modulator—to formulate a mechanistic hypothesis linking pathogen-driven immune activation to the pathogenesis of Parkinson's disease and related synucleinopathies.

What was found

The abstract reports no empirical data or quantitative metrics. It presents a mechanistic model wherein α-syn upregulation occurs as a normal immune response to viral and bacterial pathogens or environmental toxins. The authors propose that under conditions of dysregulated inflammation (driven by aging or genetic predisposition), elevated monomeric α-syn forms oligomers that are internalized by peripheral nerve terminals, undergo axonal transport to the central nervous system, and seed pathogenic fibrillar aggregates.

Why it matters

It highlights a plausible biological mechanism connecting peripheral infections and immune responses to the initiation and central propagation of alpha-synuclein pathology in neurodegenerative disorders.

Limits

The paper is a narrative review without systematic search protocols, quantitative synthesis, or new empirical data. The proposed pathway from peripheral immune-mediated upregulation to pathogenic central nervous system seeding remains a theoretical model requiring validation in longitudinal human and in vivo studies.

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