Figure 9.

Characteristic responses of subpopulation of cells with high Aβ binding affinity. A, PC12 cells were sorted in subpopulations on the basis of their affinity to bind Aβ-FITC and allowed to divide for 8 d in separate cultures. DNA fragmentation was measured after 8 d in culture (left). At day 7, a group of cells from each subpopulation was exposed to Aβ for 1 d before DNA fragmentation measurement (right). DNA fragmentation induced by Aβ was only observed in the subpopulation of cells with affinity to Aβ-FITC. B, Subpopulations of PC12 cells, sorted on the basis of their affinity to bind Aβ-FITC, were differentiated by NGF and exposed to fresh Aβ for 2 d, and the neurite outgrowth was analyzed. Aβ produced a 55% reduction of neurite outgrowth in sorted control cells (untreated). The reduction of neurite outgrowth in the subpopulation of cells with high affinity to Aβ-FITC was 82%, significantly higher (p < 0.0001) than the subpopulation of cells with no affinity to Aβ-FITC (20%) and control untreated cells (p < 0.04).