Fig. 6

TAS1R3 deficiency alters the gut microbiota composition and increases the abundance of butyrate-producing bacteria. a and b mRNA expression of PPARγ-target genes (TJPs: Tjp3, Ocln, Cldn1, and Cldn7; AMPs: Reg3g, Lyz1, Defa2, and Defa3) in the small intestine (n = 6 mice/group). Western blotting of (c) Occludin and (d) Claudin-1 expression in ND- and WD-fed Tas1r3^−/− and Tas1r3^+/+ mice and densitometric data (n = 6 mice/group). e–h Effects of TAS1R3 deficiency on the α- and β-diversity of the gut microbiota (n = 10–14 mice/group). e and f Changes in intestinal bacterial community diversity, determined by Shannon’s and Pielou’s indices. g and h Three-dimensional PCA based on Bray − Curtis and weighted UniFrac distances between all samples. Each circle represents an individual mouse. Significance was tested using PERMANOVA. i Relative abundance of bacterial phyla. Each color represents the relative abundance of a specific phylum in each sample (n = 10–14 mice/group). Only phyla with a mean relative abundance of > 0.1% are shown. j Comparison of bacterial community composition between WD-fed Tas1r3^−/− and Tas1r3^+/+ mice. Taxonomic cladogram generated from linear discriminant analysis effect size analysis of gut microbial 16S rRNA sequencing data. Taxa meeting a linear discriminant analysis threshold of > 2 and P < 0.01 are shown. k Relative abundance of genera differentially detected between the groups (n = 14 mice/group). l Fecal butyrate levels (μM/g wet weight) in WD-fed Tas1r3^−/− and Tas1r3^+/+ mice, assessed by gas chromatography-mass spectrometry (n = 20 mice/group). Data represent means ± standard errors of the mean. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001 (analysis of variance followed by Bonferroni post-hoc test or unpaired Student’s t-test). AMP, antimicrobial peptide; PCA, principal coordinate analysis; TAS1R3, taste receptor type 1 member 3; TJP, tight-junction protein; WD, western diet