(H) Representative Iba1+ immunohistochemistry in the leptomeninges of SPF, GF, ABX-treated, ASF, recolonized ASF, sDMDMm2, TLR2,3,4,7,9-deficient, SCFA-treated GF mice or FFAR2-deficient mice. Arrows indicate Iba1+ meningeal macrophages. Scale bar = 50 μm. (I-O) Quantification thereof. Each symbol represents one mouse. Three to four sections per mouse were examined. Means ± s.e.m. are indicated. No significant differences were determined by unpaired t-test or one-way ANOVA followed by Tukey's post-hoc comparison test. Data are representative of at least two independent experiments. 