Figure 1.
Absence of FXR promotes hepatomegaly and increased serum bile acids.
A) Experimental group mean cecal Helicobacter hepaticus colonization levels ± SD determined by probe-based qPCR and expressed relative to cecal DNA quantity. B) Mean mouse liver weight – body weight ratio ± SD and C) median serum bile acid levels ± IQR are shown for each experimental group. *P<0.05, **P<0.01, and ***P<0.001 vs. WT sham-treated mice.
Figure 2.
H. hepaticus infection is necessary for increased liver pathology and preneoplastic lesions in FXR KO mice.
A) Mean hepatitis index (HI) ± SD is shown for each experimental group (**P<0.01). Representative liver sections from B) sham-treated WT (HI = 0) and H. hepaticus-infected FXR KO mice showing C) typical (HI = 1.5) and D) severe (HI = 6.5) hepatitis. H&E-stain, bar = 100 µm. E) Mean FCA count ± SD is shown for each experimental group (*P<0.05). Examples of F) eosinophilic and G) clear cell foci from H. hepaticus-infected FXR KO mice (outlined by arrows; H&E-stain, bar = 600 µm).
Figure 3.
Gene expression changes associated with H. hepaticus infection and the absence of FXR.
Fold changes of A-G) pro-inflammatory (β-catenin, IL-1b, Nos2, Rela, Tlr2, TNFα, and Trp53) and H-K) metabolic (Cyp3a11, Slc10a1, Vdr, and Cyp2b10) genes determined by qPCR are shown for each group relative to WT sham mice. L) Cyp2b10 expression in infected FXR KO mice is shown based on FCA presence vs. absence (P = 0.0028). Box plots represent the average fold change relative to WT sham ±1 standard deviation. Values represent average fold change relative to uninfected WT sham. *P<0.05, **P<0.01, ***P<0.001 vs. sham-treated WT mice. #P<0.05, ##P<0.01, ###P<0.001 vs. H. hepaticus infected WT mice.
Figure 4.
FXR KO affects the alpha and beta diversity of the cecal microbiome.
A) Sham FXR KO mice showed significant decreases in OTU richness as measured by Chao1. B) Decreased alpha diversity was also observed using the Shannon diversity index when compared to sham WT and H. hepaticus infected FXR KO mice. C) Unweighted UniFrac-based PCoA plot of cecal microbial communities from WT and FXR KO mice with and without H. hepaticus infection reveals clustering based on mouse genotype and H. hepaticus status (P = 0.001 for both, PERMANOVA). D) Weighted Unifrac-based PCoA plot reveals clustering by mouse genotype (P = 0.005, PERMANOVA), but not by H. hepaticus status. *, P<0.05 against both sham WT and H. hepaticus FXR KO mice.
Table 1.
PERMANOVA analysis of Unifrac-based distance matrices.
Figure 5.
Microbiome composition by phylum.
Individual bars represent individual mice from four groups (WT sham, WT H. hepaticus, FXR KO sham and FXR KO H. hepaticus). There is a significant decrease (P<0.05, FDR <5%, ANOVA) in the phylum Firmicutes in all FXR KO mice compared to all WT mice (46.3% in FXR KO compared to 61.5% in WT).
Table 2.
Significant differences between all WT and FXR KO mice at multiple taxonomic levels.
Table 3.
ANOVA analysis of Differences in Relative Abundance at the genus level between sham and H. hepaticus infected FXR KO mice.