Figure 8: Co-housing with WT mice restores colonic epithelium inflammasome activation and improves features of DSS colitis development in Gpr43−/− mice.
(a,c) Measurement by western blot of cleaved caspase 1 on protein extracted from colonic epithelial cells from WT and from Gpr43−/− mice single-housed (a) or co-housed (c) for 2 weeks before 6 days treatment on DSS 2%. One column represents one mouse. (b,d) Clinical score (b) and IL-18 measured by enzyme-linked immunosorbent assay (d) were assessed in WT (control littermates) single-housed (WT-DSS n=5 mice), in WT co-housed for 2 weeks with Gpr43−/− mice (WT CH-DSS, n=6 mice), in Gpr43−/− single-housed (Gpr43−/−-DSS n=5 mice) and in Gpr43−/− co-housed with WT mice for 2 weeks (Gpr43−/− CH-DSS n=6 mice). Mice were fed on DSS 2% for 6 days. (e–h) Analysis of gut bacterial communities by Observed Species (WT co-housed in orange, WT single-housed in green, Gpr43−/− co-housed in red and Gpr43−/− single-housed in blue), unweighted UniFrac principal coordinate analyses (PCoA) plot (e) is presented in single-housed WT (red triangles), in single-housed Gpr43−/− mice (green squares), in WT co-housed for 2 weeks with Gpr43−/− mice (grey triangles) and in Gpr43−/− co-housed for 2 weeks with WT mice (blue circles). Scale bars, 200 μm. (f–h) Increased relative abundance of Porphyromonadaceae in Gpr43−/− after co-housing. OTUs 5,485 (f), 2,242 (g) and 2,849 (h) of the Parabacteroides genus, family Porphyromonadaceae, were found significantly (with respectively ***, **, *** for P values 0.0043, 5.5E−4 and 0.0010) increased in Gpr43−/− mice following co-housing. Representative 16S rRNA sequences were deposited in the EMBL database with sequence accession numbers: HG970160 for OTU5485, HG970161 for OTU2242 and HG970162 for OTU2849. The results are shown as mean±s.e.m. (b,d). With *P<0.05 and **P<0.01 determined by two-way analysis of variance as group effect with $P<0.05, $$P<0.01, $$$P<0.001 and $$$$P<0.0001 comparing WT versus Gpr43−/−, ###P<0.001 comparing Gpr43−/− CH versus not CH by Tukey’s multiple analysis and *P<0.05, **P<0.01 and ****P<0.001 determined by t-test. KA: knockout after cohousing; KB: knockout before cohousing; WA: wild-type after cohousing; WB: wild-type before cohousing.
