BETA-AMYLOID PEPTIDE-INDUCED CYTOSKELETAL REORGANIZATION IN CULTURED ASTROCYTES

The effects of beta-amyroid (25-35) (beta A) on cultured astrocytes fr om rat cortex were studied and compared with those of a scrambled pept ide and with untreated cultures, Single addition (from 5 to 200 mu g/m l) of beta A peptide induced a marked morphological change in astrocyt es, changing their flat polygonal shape into stellate process-bearing morphology, The changes induced by beta A were concentration and time- dependent. The addition of the scrambled peptide did not alter cell vi ability in comparison with untreated astrocyte cultures, However, cell viability was dose-dependently decreased by beta A. A subpopulation o f beta A-treated astrocytes showed an increase in glial fibrillary aci dic protein (GFAP) and Vimentin (Vim) immunostaining while other react ive astrocyte markers such as S100 beta, MAP2, and ApoE remained unalt ered or undetectable. The morphorogical changes in beta A-treated astr ocytes appeared to be mainly due to a cytoskeletal reorganization, sin ce the total amounts of GFAP and Vim proteins were not essentially mod ified. These results strongly suggest that astrocytes are another cell ular target of the effects of beta A and this may be relevant to under standing the neuropathology of Alzheimer's disease. (C) 1997 WiIey-Lis s, Inc.