FIGURE 4.

Aβ-induced neuronal loss is sequence dependent and microglia-mediated. A, reverse sequence peptide Aβ42–1 (250 nm) or vehicle dimethyl sulfoxide (DMSO, 0.05%) does not cause neuronal loss over 3 days of treatment. B, neuronal loss is not prevented by endotoxin removal, when Aβ1–42 is preincubated for 30 min at 37 °C with polymyxin B (PMX, 1000 units/ml); however, neuronal loss induced by LPS (100 ng/ml) is completely prevented by LPS pre-incubation with polymyxin B. C, neuronal loss induced by 250 nm Aβ1–42 is completely prevented by selective depletion of microglial cells with l-leucine-methyl esther (LME), whereas neurotoxicity of 10 μm Aβ1–42 is microglia-independent. Data presented as means ± S.E. for ≥3 independent experiments. ***, p < 0.001 versus control; ###, p < 0.001 versus Aβ1–42 (A and C) or LPS (B).