Arc protein controls how Alzheimer's spreads between neurons

Arc protein acts as a critical gatekeeper in Alzheimer's progression by controlling how pathological tau gets packaged into extracellular vesicles and transmitted between neurons. In Arc-knockout mice, intercellular tau transmission is almost entirely absent, while in brain samples from Alzheimer's patients, Arc levels in vesicles show strong positive correlation with phosphorylated tau levels. The finding emerges from transgenic mice carrying mutant tau and analysis of human brain-derived vesicles, where Arc and tau travel together in these transport structures. Intracellular tau accumulation increases without Arc, suggesting that blocking this mechanism could slow the neurodegenerative cascade without simply trapping damaged protein inside cells. For biohackers and prevention-focused readers tracking emerging Alzheimer's interventions, this discovery opens the door to Arc-targeted drugs as a strategy to interrupt tau pathology spread before significant cognitive decline occurs.