β-Amyloid peptide induced cytoskeletal reorganization in cultured astrocytes

Abstract

The effects of β-amyloid (25-35) (βA) on cultured astrocytes from rat cortex were studied and compared with those of a scrambled peptide and with untreated cultures. Single addition (from 5 to 200 μg/ml) of βA peptide induced a marked morphological change in astrocytes, changing their flat polygonal shape into stellate process-bearing morphology. The changes induced by βA were concentration and time-dependent. The addition of the scrambled peptide did not alter cell viability in comparison with untreated astrocyte cultures. However, cell viability was dose-dependently decreased by βA. A subpopulation of βA-treated astrocytes showed an increase in glial fibrillary acidic protein (GFAP) and Vimentin (Vim) immunostaining while other reactive astrocyte markers such as S100β, MAP2, and ApoE remained unaltered or undetectable. The morphological changes in βA-treated astrocytes appeared to be mainly due to a cytoskeletal reorganization, since the total amounts of GFAP and Vim proteins were not essentially modified. These results strongly suggest that astrocytes are another cellular target of the effects of βA and this may he relevant to understanding the neuropathology of Alzheimer's disease.