Mice lacking intestinal Nr1i2 have normal intestinal homeostasis under steady-state conditions and are not hypersensitive to inflammation under lipopolysaccharide treatment

Nr1i2, a nuclear receptor known for its key function in xenobiotic detoxification, has emerged as a potential regulator of intestinal homeostasis and inflammation. However, the role of Nr1i2 in different intestinal segments remains poorly known. Moreover, in vivo investigations on intestinal Nr1i2 have essentially been performed in whole-body Nr1i2 knockout (Nr1i2(-/-)) mice where the deletion of Nr1i2 in all tissues may affect the intestinal phenotype. To better understand the role of Nr1i2 in the intestine, we generated intestinal epithelial-specific Nr1i2 knockout (iNr1i2(-/-)) mice and studied the duodenum, jejunum, ileum, and colon of these animals during steady-state conditions and lipopolysaccharide (LPS)-induced inflammation. As compared to control (iNr1i2(+/+)) mice, iNr1i2(-/-) mice showed normal intestinal permeability as assessed by in vivo FITC-dextran test. The expression of genes involved in inflammation, tight-and adherens-junction, proliferation, glucose, and lipid metabolism was comparable in the duodenum, jejunum, ileum, and colon of iNr1i2(-/-) and iNr1i2(+/+) mice. In line with these findings, histological analyses of the jejunum revealed no difference between iNr1i2(-/-) and iNr1i2(+/+) mice. When treated with LPS, the intestine of iNr1i2(-/-) mice had no increased inflammatory response as compared to iNr1i2(+/+) mice. Moreover, the health monitoring of LPS-treated iNr1i2(-/-) and iNr1i2(+/+) mice was similar. Taken together, our results demonstrate that the specific deletion of Nr1i2 in the intestinal epithelium does not cause major intestinal damages in mice during both steady-state and inflammatory conditions.

Automated summary

Nr1i2, a nuclear receptor known for its role in xenobiotic detoxification, may also regulate intestinal homeostasis and inflammation. In this study, researchers generated intestinal epithelial-specific Nr1i2 knockout mice and found that the deletion of Nr1i2 in the intestine did not cause major damages during steady-state and inflammatory conditions. The expression of genes involved in inflammation, tight and adherens junctions, proliferation, glucose, and lipid metabolism was comparable between the knockout mice and control mice.