Fig. 7

GM1 dampens microglia reactivation in an experimental model of tolerance. A Experimental design. Microglia were stimulated with LPS (100 ng/ml) for 12 h, then washed and let recover in serum-free medium for 24 h in the presence or absence of GM1 (50 µM). After several washes to remove GM1, a second stimulation with LPS (100 ng/ml) was performed for 6 h, at the end of which, cytokine expression and secretion were measured. B Expression of Il-1b, Il-6 and Tnf mRNA was normalized over the geometric mean of three housekeeping genes (Normalization Index). N = 3. Ratio paired t-test. C TNF secreted in medium. Data are presented as a paired estimation plot including individual data points (independent experiments), mean values shown by bars, and the bootstrap 95% confidence interval for the effect size. N = 3. §, p = 0 as per paired estimation plot. D Fpr1 expression was measured in microglia stimulated twice with LPS as per experimental design in (A). GM1 presence during the recovery period represses the expression of the non-tolerizeable gene Fpr1. E Cells were treated as in (A). The expression of Irak-3 is similar in Q7/7 and Q140/140 cells. The presence of GM1 during the recovery period prevents upregulation of Irak-3 after re-stimulation with LPS. Two-way ANOVA with Sidak’s multiple comparison post-test was conducted in D and E. Bars are mean values ± STDEV. *p < 0.05, **p < 0.01, ****p < 0.0001