TNF-related apoptosis-inducing ligand mediates human neuronal apoptosis: links to HIV-1-associated dementia.

TNF-related apoptosis-inducing ligand (TRAIL) is a type II integral membrane protein that interacts with multiple receptors and cell types including neurons. In this report, TRAIL protein levels were increased in human monocyte-derived macrophages (MDM) after HIV-1 infection and immune activation. In HIV-1 encephalitic (HIVE) human brain tissue, TRAIL-expressing macrophages were found in association with active caspase-3 positive neurons. Cytotoxic TRAIL receptors 1 and 2 were expressed on neurons in primary human fetal cultures and HIV-1 encephalitic brain tissue. Furthermore, TRAIL induced a dose-dependent effect on neuronal apoptosis. These results support a role for TRAIL in mononuclear phagocyte (MP)-mediated neurotoxicity in HIV-1-associated dementia (HAD).