Deposition of amyloid fibrils promotes cell-surface accumulation of amyloid beta precursor protein.

HEREDIA L; LIN R; SOLA VIGO F; KEDIKIAN G; BUSCIGLIO J; LORENZO A

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2004 vol. 16 p. 617 - 617

p class="abstract">Amyloid beta protein (Abeta) deposition and neuronal degeneration are characteristic pathological features of Alzheimer´s disease (AD). In vitro, Abeta fibrils (fAbeta) induce neuronal degeneration reminiscent to AD, but the mechanism of neurotoxicity is unknown. Here we show that amyloid fibrils increase the level of cell-surface full-length amyloid beta precursor protein (h-AbetaPP) and secreted AbetaPP (s-AbetaPP). Pulse-chase analysis indicated that fAbeta selectively inhibited the turnover of cell-surface AbetaPP, without altering its intracellular levels. FAbeta-induced AbetaPP accumulation was not abrogated by cycloheximide, suggesting that increased protein synthesis is not critically required. Abeta fibrils sequester s-AbetaPP from the culture medium and promote its accumulation at the cell surface, indicating that binding of Abeta fibrils mediates AbetaPP accumulation. A time course analysis of Abeta treatment showed that AbetaPP level is elevated before s