TRAIL is expressed in the brain cells of Alzheimerʼs disease patients

Tumour-necrosis-factor-related apoptosis-inducing ligand (TRAIL) is a novel cytokine characterized by selective killing activity against tumour cells. We recently found that β-amyloid-induced apoptosis in a human neuronal cell line was mediated via induction of TRAIL. Here, we show that TRAIL is specifically expressed in the brain of Alzheimerʼs disease (AD) patients and completely absent in the brain of non-demented patients. TRAIL-like immunoreactivity was localized in AD affected regions, such as cerebral cortex, often in the proximity of Congo-red-positive amyloid plaques. These findings suggest that neurons represent an independent and potential source of TRAIL, suggesting that the latter acts redundantly with other noxious stimuli in neurodegenerative diseases characterized by amyloidosis and neuroinflammation.