Fig. 9

Microglial repopulation blunts proinflammatory responses to TLR4 and TLR7 agonists. Ex vivo OHSCs underwent microglial depletion followed by repopulation. On day 14 of repopulation, slices were treated with agonists to TLR4 (LPS 100 ng/ml) and TLR7 (Imiquimod, IMQ 5 μg/ml) for 16 h. Induction of proinflammatory genes TNFα and IL-1β was assessed by RT-PCR. a IL-1β was strongly induced in naïve cultures (28DIV) by LPS (44-fold), and IMQ (158-fold). Microglia-repopulated slices showed reduced induction of TNFα due to LPS (20-fold vs control, 55% reduction) and IMQ (38-fold vs control, 76% reduction). b TNFα was induced in naïve cultures (28DIV) by LPS (4-fold), and IMQ (13.6-fold). Microglia-repopulated slices showed reduced induction of TNFα due to LPS (2.5-fold vs control, 40% reduction) and IMQ (7.4-fold vs control, 45% reduction). **p < 0.01, ***p < 0.001 vs control. †p < 0.05 vs LPS or IMQ alone. N = 3 replicates/group, two independent experiments per condition. c Illustration depicting changes in immune gene expression in response to TLR agonists after microglial repopulation