Fig 2: Il10 deficiency leads to increased infarct sizes, enhanced brain atrophy, and poorer long-term outcome following tMCAO. MRI was used to quantify infarct volume at day 3 (A) and cortical atrophy volume at day 14 (C) after tMCAO in WT control and Il10−/− mice (representative T2 image). B Triphenyltetrazolium chloride (TTC) staining was used for the evaluation of infarct volume at day 7 (representative TTC brain slices). D Composite neurological score was performed on day 14 after tMCAO. E Il10/GFP-positive cells were visualized in the penumbra area of the ischemic hemisphere by GFP counterstaining in FIR-tiger mice 14 days after tMCAO (green, Il10/GFP-positive cells; red, CD45-positive cells; blue, 40,6-diamidino-2-phenylindole nuclear staining; scale bar 20 µm). Infarct data are presented as mean ± SEM of 8–10 WT and 6–10 Il10−/− mice (A, B), atrophy data as mean ± SEM of 11 WT and 13 Il10−/− mice (C), and neurological score of 12 WT and 11 Il10−/− mice (D). Statistical significances were analyzed by Student t test (A–C) and Mann–Whitney U test (D). *P < 0.05 and ***P < 0.001

Fig 3: Treatment of neonates with butyrate decreases hepatobiliary injury.A Diagrammatic outline of gavaging RRV-infected neonatal mice with sodium butyrate. B Jaundice (generalized linear mixed effect model with logit link and two-sided Wald test with Bonferroni correction; ****p < 0.0001) and C survival (two-sided log-rank test; ***p < 0.001) rates in RRV-infected newborn mice treated daily with butyrate or PBS. D Virus titers in EHBD and livers at day 7 after RRV infection of newborn mice from water-fed dams (mean ± SD, two-tailed unpaired t test with Welch’s correction; n = 5 per group; ns = not significant) and E section of EHBD from butyrate-treated mice 14 days after RRV. In all, 15–30 EHBD sections (corresponding to >100 sections at ×200 or ×400 magnification fields from n = 11 mice) stained with H&E per tissue specimen were evaluated for histology analysis. Scale bar = 50 µM. Foxp3 (F) and Il10 (G) mRNA in RRV-naive or primed hepatic mononuclear cells cultured with or without butyrate, normalized to Gapdh (mean ± SD, two-tailed ANOVA with Duncan’s multiple comparisons, n = 3 per group. *p < 0.05, **p < 0.01, ns = not significant). Source data for this figure are provided as a Source data file.

Fig 4: Murine fecal metabolites suppress activated immune cells and are enriched with hypoxanthine/inosine and glutamate/glutamine.A Schematic illustration of in vitro fecal supernatant–immune cell cultures and stool metabolite analysis. mRNA expression for Il10 (B), Foxp3 (C), and Tnfa (D) as a ratio to Gapdh in RRV-primed hepatic MNCs cultured in the presence of fecal supernatants from neonatal mice of water- or butyrate-fed mothers (mean ± SD, two-tailed unpaired Student’s t test, n = 4 per group; *p < 0.05, **p < 0.01, ***p < 0.001). E NMDS and ANOSIM of metabolites in fecal supernatants of neonatal mice from water- or butyrate-fed mothers at 14 days of age. F Volcano plot illustrating fecal metabolites with p values and fold changes between neonatal mice from water- and butyrate-fed mothers (inset depicts metabolites of lower distance). The replicate values were determined using biologically distinct samples and p values calculated using unpaired Student’s t test with two-tailed distribution. G Fecal metabolites ordered by Euclidean distance measured from the volcano plot. Source data for this figure are provided as a Source data file.

Fig 5: Neutralization of IL-17A abolishes the worse outcome of Il10−/− mice. Triphenyltetrazolium chloride staining was used for evaluation of infarct volume at day 7 of IL-17A antibody (A) or IgG control (C) treated Il10−/− and WT control mice. Bederson score was performed 7 days after tMCAO IL-17A antibody (B) or in IgG control (D) treated group. Infarct data are presented as mean ± SEM of 9–11 WT and 6–9 Il10−/− mice per group. Bederson score as mean ± SEM of 9–11 WT and 7–10 Il10−/− mice per group. Statistical significances were analyzed by Student t test (A, C) and Mann–Whitney U test (B, D). *P < 0.05