Brain HealthWhy Alzheimer's and Parkinson's Share a Protein Misfolding Network
For decades, Alzheimer's was blamed on amyloid-beta, Parkinson's on alpha-synuclein. A new review in Ageing Research Reviews challenges this one-protein-one-disease thinking. The authors show that key misfolded proteins — Tau, alpha-synuclein, amyloid-beta, and TDP-43 — don't act alone. They cross-seed each other, co-localize in brain tissue, and amplify each other's toxicity. This co-aggregation is shaped by aging-related changes in cell membranes, oxidative stress, and the brain's protein-cleanup systems. The review calls for new biomarkers that detect these mixed pathologies in spinal fluid and cellular vesicles, and for therapies that target multiple proteins simultaneously. The practical upshot: many patients with dementia have overlapping pathologies, and treatments aimed at a single protein may be why so many clinical trials have failed.
