Figure 1.

Dietary tryptophan is processed differently in lupus-prone and control mice

(A) PLS-DA plots of serum and fecal metabolites from B6 and TC mice fed high or low tryptophan for 1 month (N = 4 per group). For simplicity, only the positive mode is shown.

(B) Heatmaps of tryptophan metabolites differently represented in serum and feces among the 4 groups (p < 0.05 analyzed by ANOVA). Data are shown as Log10 transformed mean for each group ordered from the highest to lowest in the B6 Trp low group. Metabolites below the red horizontal lines were changed by dietary tryptophan to a similar extent in both strains. Metabolites above the red lines were affected differently by tryptophan between the two strains, i.e. there was a significant difference between the Trp high groups with no difference between Trp low groups, or there was a difference between Trp low and high in only one of the strains.

(C) Top 5 serum and fecal tryptophan metabolites ranked separately for B6 and TC as the most changed by high dietary tryptophan. The values show the difference between high and low tryptophan as a percentage of the low tryptophan value, all Log10-transformed, as shown in the heatmaps.

(D–G) Values for tryptophan and endogenous metabolites.

(H–J) Values for microbial metabolites. C–J: Graphs show individual mice with mean ± SEM t tests, ∗p < 0.05, ∗∗p < 0.01.