FIGURE 8.

ProNGF rescues primed PC12 cells after NGF withdrawal. PC12 cells were primed with 50 ng/ml of 2.5S NGF for 11 days. After removing NGF and serum, cells were treated with 0.4 nm proNGFhis (A), proNGF(R−1G) (B), WT-NGF (C), or baculovirus-infected insect cell conditioned medium (D). After 48 h, cells were fixed and stained with TUJ-1 antibody and subjected to Hoechst staining. In contrast to medium alone, proNGFhis, proNGF(R−1G), and WT-NGF rescued cells from death after NGF withdrawal. Yellow arrows show representative live cells and white arrows show representative dead cells. Both NGF and proNGF reduced apoptosis compared with medium alone after NGF withdrawal (E). *, p < 0.05 compared to medium, one way analysis of variance followed by post hoc Tukey's test. Error bars represent S.E. for n = 3 per group except proNGF(R−1G) with n = 2.