Figure 3.

Dectin-1 (CLR)-activated macrophages cause toxicity and axonal degeneration. MCM from macrophages activated via CLR plus TLR2 (TLR2+CLR, zymosan) or CLR alone (depleted zymosan) cause neurotoxicity and axonal degeneration, whereas MCM from TLR2-activated macrophages is neuroprotective or enhances axon growth. A, B, Total numbers of DRG neurons (A; normalized to DRG neurons incubated with unstimulated MCM; ANOVA, p = 0.0055; *p < 0.05 vs other conditions) and overall density of β-tubulin staining (B; ANOVA, p = 0.0028, *p = 0.01 vs CLR) were quantified as indices of neuron survival and axon degeneration, respectively. DRG neurons were plated at low density (400 cells per coverslip) and then, beginning on day 3 in vitro, were stimulated with MCM for 2 d (A). C–F, Representative images of adult DRG neurons cultured for 5 d in the presence of different types of MCM (quantified in B). Data are representative of three independent experiments. Dotted line in A and B represents unstimulated MCM. Scale bar, 50 μm.