Two-tailed Student’s t test was used to determine significant differences between data

groups. All analyses were performed using one-way analysis of variance (ANOVA). P < 0.05 (*) was considered statistically significant. Two loxP sequences flank exons 4, 5, and 6 of the murine FXR allele (FXR Fl/Fl). FXR Fl/Fl mice were crossed with the albumin-cre or villin-cre mice to delete FXR gene specifically in liver or intestine, respectively. After correct genotyping, western blotting to measure FXR protein was performed using total protein extracted from liver and ileum. The results indicated no FXR expression in the liver of ΔL-FXR mice. However, liver FXR protein levels were comparable between the FXR Fl/Fl and ΔIN-FXR mice (Fig. 1A). Similarly, no ileum FXR expression was detected in the ΔIN-FXR mice (Fig. 1B). We previously showed that FXR in liver was Adriamycin manufacturer required for promoting liver regeneration.

To confirm the previous observation that hepatic FXR is required to promote liver regeneration, we compared the liver regeneration after 70% PH in FXR Fl/Fl, ΔL-FXR, and FXR KO mice. As expected, a significant delay in hepatocyte proliferation was observed in ΔL-FXR animals compared Lenvatinib supplier to FXR Fl/Fl mice at 24 hours, 36 hours, and 72 hours after surgery. Fewer BrdU-positive hepatocytes were present in ΔL-FXR mice than in FXR Fl/Fl mice (Fig. 2A). In FXR Fl/Fl mice, the hepatocyte Fossariinae proliferation peaked at 36 hours after 70% PH, but this peak was strongly reduced in ΔL-FXR mice compared to the FXR Fl/Fl mice (Fig. 2A). These results suggest that hepatic FXR is required to promote liver regeneration. However, to our surprise, compared to ΔL-FXR mice, FXR KO mice showed significantly decreased BrdU incorporation in the liver at 36 hours and 72 hours (Fig. 2A), suggesting that FXR in other tissues may also contribute to a maximum effect on promoting liver regeneration. We also compared the serum bile acid levels in FXR Fl/Fl, ΔL-FXR,

and FXR KO mice. As expected, serum bile acid levels were significantly higher in the FXR KO and ΔL-FXR mice compared to the FXR Fl/Fl mice at 24 hours and 36 hours after 70% PH. On day 3, serum bile acid levels in ΔL-FXR mice returned to a comparable level compared to the control mice. However, bile acid levels were still significantly higher in FXR KO mice at day 3 (Fig. 2B). This suggests that, although hepatic FXR plays a role in suppressing bile acid levels after 70% PH, FXR in other tissues such as intestine may be required to suppress bile acid levels at later stages after 70% PH. Consistently, the gene encoding the rate-limiting enzyme of bile acids synthesis, CYP7a1, was suppressed in all three groups of mice after 70% PH, but CYP7a1 messenger RNA (mRNA) levels were much higher in ΔL-FXR and FXR KO mice compared to the FXR Fl/Fl mice (Fig. 2C). FXR was shown previously to directly activate the Foxm1b gene after 70% PH.