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. 2023 Sep 28;72(12):2272–2285. doi: 10.1136/gutjnl-2023-329543

Figure 4.

Figure 4

Lactobacillus gallinarum produced tryptophan metabolites in vitro and in vivo. (A) Untargeted metabolomics showing the heatmap analysis of BHI, E. coli and L. gallinarum culture supernatant in vitro. (B) Untargeted metabolomics showing heatmap analysis of stool samples from MC38 syngeneic mouse model revealed a differential abundance of metabolites in BHI-treated, E. coli-treated and L. gallinarum-treated mice. E. coli mutant expressing aromatic amino acid aminotransferase (E. coli-ArAT) improved ant-PD1 efficacy in CT26 syngeneic mouse model, as evidenced by (C) representative tumour picture, (D) tumour weight and (E) tumour volume. (F) No significant difference of IAld was observed in serum samples between groups. An elevated level of ICA was detected in serum after L. gallinarum gavage. (G) No significant difference of IAld was observed in tumour tissues between groups. ICA was enriched in tumour tissues of L. gallinarum-treated mice in MC38 syngeneic mouse model. Statistical significance was determined by Kruskal-Wallis test, followed by Dunn’s multiple comparison test. Statistical significance of tumour growth curve over time was determined by two-way analysis of variance. *p<0.05, **p<0.01. ArAT, aromatic amino acid aminotransferase; E.c., E. coli; IAld, indole-3-carboxaldehyde; ICA, indole-3-carboxylic acid. L.g., L. gallinarum; WT, wild-type; αPD1, anti-PD1.