Ontology highlight
ABSTRACT: Background and aims
Dysfunction of the vitamin D receptor [VDR] contributes to the aetiology of IBD by regulating autophagy, immune response, and mucosal permeability. VDR directly controls the paracellular tight junction protein Claudin-2. Claudin-2 and Claudin-15 are unique in maintaining paracellular permeability. Interestingly, claudin-15 mRNA was downregulated in patients with ulcerative colitis. However, the exact mechanism of Claudin-15 regulation in colitis is still unknown. Here, we investigated the protective role of VDR against intestinal inflammation via upregulating Claudin-15.Methods
We analysed the correlation of Claudin-15 with the reduction of VDR in human colitis. We generated intestinal epithelial overexpression of VDR [O-VDR] mice to study the gain of function of VDR in colitis. Intestinal epithelial VDR knockout [VDR∆IEC] mice were used for the loss of function study. Colonoids and SKCO15 cells were used as in vitro models.Results
Reduced Claudin-15 was significantly correlated with decreased VDR along the colonic epithelium of human IBD. O-VDR mice showed decreased susceptibility to chemically and bacterially induced colitis and marked increased Claudin-15 expression [both mRNA and protein] in the colon. Correspondingly, colonic Claudin-15 was reduced in VDR∆IEC mice, which were susceptible to colitis. Overexpression of intestinal epithelial VDR and vitamin D treatment resulted in a significantly increased Claudin-15. ChIP assays identified the direct binding of VDR to the claudin-15 promoter, suggesting that claudin-15 is a target gene of VDR.Conclusion
We demonstrated the mechanism of VDR upregulation of Claudin-15 to protect against colitis. This might enlighten the mechanism of barrier dysfunction in IBD and potential therapeutic strategies to inhibit inflammation.
SUBMITTER: Chatterjee I
PROVIDER: S-EPMC8495491 | biostudies-literature | 2021 Oct
REPOSITORIES: biostudies-literature
Journal of Crohn's & colitis 20211001 10
<h4>Background and aims</h4>Dysfunction of the vitamin D receptor [VDR] contributes to the aetiology of IBD by regulating autophagy, immune response, and mucosal permeability. VDR directly controls the paracellular tight junction protein Claudin-2. Claudin-2 and Claudin-15 are unique in maintaining paracellular permeability. Interestingly, claudin-15 mRNA was downregulated in patients with ulcerative colitis. However, the exact mechanism of Claudin-15 regulation in colitis is still unknown. Here ...[more]