Interleukin-1β dissociates β-amyloid precursor protein and β-amyloid peptide secretion

A heightened production of interleukin 1β(IL-1β) has been reported in microglial-associated amyloid deposits in Alzheimer's disease (AD) brains. These plaques are composed predominantly of β/A4 peptide derived from β-amyloid precursor protein (βAPP). We demonstrate that short-term (1 h) IL-1β-treatment increases βAPP s secretion and concomitantly decreases cell-associated βAPP in human H4 neuroglioma cells. Long-term (5 h) IL-1β treatment did not alter secreted or cell-associated βAPP content. In contrast, the secretion of β/A4-containing epitope was not affected by short-term IL-1β stimulation; however, long-term IL-1β treatment decreased the amount of β/A4-containing epitope secreted from the cells. These results show that IL-1β modifies the processing and secretion of βAPP to exacerbate perhaps the neuropathology of AD.