HEPARIN INDUCTION OF THE BETA-AMYLOID PRECURSOR PROTEIN (A-BETA-PP) IN A NEURAL CELL-LINE IS REGULATED BY CELL CONFLUENCY STATE

The beta-amyloid precursor protein (A beta PP) is a heparin-binding glycoprotein which plays a role in the mediation of neural cell adhesion. Mouse neuro-2A neuroblastoma cells cultured on a collagen substrate generally expressed significantly higher levels of A beta PP than those grown on tissue-cultureplastic. The addition of heparin to non-confluent cell cultures resulted in decreased A beta PP levels, this being independent of the culture substratum. Heparin, however increased A beta PP levels in confluent cells plated on tissue-culture plastic but had no effect on collagen-based cells. These results suggest that the effect of heparin on neural A beta PP levels is influenced both by the cellular interaction with components of the extracellular matrix and also the cell confluency state.