Fig. 1

Siglec-E suppresses prototypical proinflammatory mediators in LPS-activated microglia. A Mouse primary brain microglia from C57BL/6 wild type and Siglec-E knockout pups were prepared in 48-well plates (4 × 10⁴ cells/well). The purity of microglia in these cultures was assessed by immunostaining for the microglial marker Iba-1 (red fluorescence) and compared (n = 9, p = 0.678, Mann–Whitney U test). Note that cell nuclei were stained with DAPI (blue fluorescence) to illustrate all cell types. Scale bar: 50 μm. The cultured cells were then stimulated with LPS (0, 1, 10, or 100 ng/mL) for 16 h. A number of key proinflammatory mediators that were secreted by LPS-activated microglia into the culture medium, such as PGE₂ (B), IL-1β (C), IL-6 (D), and TNF-α (E), were measured by ELISA. Note that all these conventional proinflammatory mediators produced by microglia were induced by LPS treatment in a concentration-dependent manner and were further dramatically increased in the absence of Siglec-E (n = 8–12, *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001, two-way ANOVA with post hoc Šidák multiple comparisons). All data are presented as mean ± SEM