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 gl ycoprotein 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 thos e grown on tissue-cultureplastic. The addition of heparin to non-confl uent cell cultures resulted in decreased A beta PP levels, this being independent of the culture substratum. Heparin, however increased A be ta PP levels in confluent cells plated on tissue-culture plastic but h ad no effect on collagen-based cells. These results suggest that the e ffect of heparin on neural A beta PP levels is influenced both by the cellular interaction with components of the extracellular matrix and a lso the cell confluency state.