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• W3134265951 abstract "We previously showed that the vitamin D receptor (VDR) plays a crucial role in acute inflammatory bowel disease and that intestinal fibrosis is a common complication of Crohn’s disease (CD). Epithelial–mesenchymal transition (EMT) is an important hallmark of fibrogenesis through which epithelial cells lose their epithelial phenotype and transform into mesenchymal cells. It is known that the VDR plays an essential role in epithelial integrity and mitochondrial function, but its role in intestinal fibrosis remains unknown. Here, we investigated whether the VDR is involved in epithelial mitochondrial dysfunction that results in EMT in intestinal fibrosis. Using human CD samples, intestine-specific VDR-KO mice, and fibroblast cellular models, we showed that the expression of the VDR was significantly lower in intestinal stenotic areas than in nonstenotic areas in patients with chronic CD. Genetic deletion of the VDR in the intestinal epithelium exacerbated intestinal fibrosis in mice administered with dextran sulfate sodium or 2,4,6-trinitrobenzene sulfonic acid, two experimental colitis inducers. In addition, we found that vitamin D dietary intervention regulated intestinal fibrosis by modulating the intestinal expression of the VDR. Mechanistically, knocking down the VDR in both CCD-18Co cells and human primary colonic fibroblasts promoted fibroblast activation, whereas VDR overexpression or VDR agonist administration inhibited fibroblast activation. Further analysis illustrated that the VDR inhibited EMT in the HT29 cell model and that mitochondrial dysfunction mediated epithelial integrity and barrier function in VDR-deficient epithelial cells. Together, our data for the first time demonstrate that VDR activation alleviates intestinal fibrosis by inhibiting fibroblast activation and epithelial mitochondria-mediated EMT. We previously showed that the vitamin D receptor (VDR) plays a crucial role in acute inflammatory bowel disease and that intestinal fibrosis is a common complication of Crohn’s disease (CD). Epithelial–mesenchymal transition (EMT) is an important hallmark of fibrogenesis through which epithelial cells lose their epithelial phenotype and transform into mesenchymal cells. It is known that the VDR plays an essential role in epithelial integrity and mitochondrial function, but its role in intestinal fibrosis remains unknown. Here, we investigated whether the VDR is involved in epithelial mitochondrial dysfunction that results in EMT in intestinal fibrosis. Using human CD samples, intestine-specific VDR-KO mice, and fibroblast cellular models, we showed that the expression of the VDR was significantly lower in intestinal stenotic areas than in nonstenotic areas in patients with chronic CD. Genetic deletion of the VDR in the intestinal epithelium exacerbated intestinal fibrosis in mice administered with dextran sulfate sodium or 2,4,6-trinitrobenzene sulfonic acid, two experimental colitis inducers. In addition, we found that vitamin D dietary intervention regulated intestinal fibrosis by modulating the intestinal expression of the VDR. Mechanistically, knocking down the VDR in both CCD-18Co cells and human primary colonic fibroblasts promoted fibroblast activation, whereas VDR overexpression or VDR agonist administration inhibited fibroblast activation. Further analysis illustrated that the VDR inhibited EMT in the HT29 cell model and that mitochondrial dysfunction mediated epithelial integrity and barrier function in VDR-deficient epithelial cells. Together, our data for the first time demonstrate that VDR activation alleviates intestinal fibrosis by inhibiting fibroblast activation and epithelial mitochondria-mediated EMT. Intestinal fibrosis is a common complication of Crohn’s disease (CD), and the underlying mechanism has not been fully clarified (1Torres J. Mehandru S. Colombel J.F. Peyrin-Biroulet L. Crohn's disease.Lancet. 2017; 389: 1741-1755Abstract Full Text Full Text PDF PubMed Scopus (1005) Google Scholar). Repeated episodes of inflammation cause extracellular matrix (ECM) deposition in the mucosa and submucosa, and patients with CD gradually develop intestinal fibrosis (2Thia K.T. Sandborn W.J. Harmsen W.S. Zinsmeister A.R. Loftus Jr., E.V. Risk factors associated with progression to intestinal complications of Crohn's disease in a population-based cohort.Gastroenterology. 2010; 139: 1147-1155Abstract Full Text Full Text PDF PubMed Scopus (485) Google Scholar). As reported, 30% to 50% of patients with CD develop intestinal fibrosis, which is characterized by lumen stenosis and complicated by fistulas and local abscesses, within 10 years (3Wang Z.T. Hu J.J. Fan R. Zhou J. Zhong J. RAGE gene three polymorphisms with Crohn's disease susceptibility in Chinese Han population.World J. Gastroenterol. 2014; 20: 2397-2402Crossref PubMed Scopus (22) Google Scholar, 4Rieder F. Zimmermann E.M. Remzi F.H. Sandborn W.J. Crohn's disease complicated by strictures: A systematic review.Gut. 2013; 62: 1072-1084Crossref PubMed Scopus (308) Google Scholar). In addition, except for surgical resection, there is no effective way to eliminate symptoms, and the recurrence rate after surgery is as high as 55% to 70% within 10 years (5Peyrin-Biroulet L. Loftus Jr., E.V. Colombel J.F. Sandborn W.J. The natural history of adult Crohn's disease in population-based cohorts.Am. J. Gastroenterol. 2010; 105: 289-297Crossref PubMed Scopus (679) Google Scholar). Although fibrosis is caused by repeated episodes of inflammation, controlling CD activity alone cannot prevent or reverse intestinal fibrosis (6Rockey D.C. Bell P.D. Hill J.A. Fibrosis--a common pathway to organ injury and failure.N. Engl. J. Med. 2015; 373: 96Crossref PubMed Scopus (6) Google Scholar). Therefore, it is vital to elucidate the pathological mechanism and explore potential targets for the intervention and treatment of intestinal fibrosis. Luminal narrowing and obstruction, which are evident in the intestinal fibrotic process, are characterized by excessive accumulation of ECM components (7Speca S. Rousseaux C. Dubuquoy C. Rieder F. Vetuschi A. Sferra R. Giusti I. Bertin B. Dubuquoy L. Gaudio E. Desreumaux P. Latella G. Novel PPARgamma modulator GED-0507-34 levo ameliorates inflammation-driven intestinal fibrosis.Inflamm. Bowel Dis. 2016; 22: 279-292Crossref PubMed Scopus (60) Google Scholar). ECM deposition mainly results from the activation of myofibroblasts, which originate from resident mesenchymal cells (8Rieder F. Karrasch T. Ben-Horin S. Schirbel A. Ehehalt R. Wehkamp J. de Haar C. Velin D. Latella G. Scaldaferri F. Rogler G. Higgins P. Sans M. Results of the 2nd scientific workshop of the ECCO (III): Basic mechanisms of intestinal healing.J. Crohns Colitis. 2012; 6: 373-385Abstract Full Text Full Text PDF PubMed Scopus (46) Google Scholar, 9Speca S. Giusti I. Rieder F. Latella G. Cellular and molecular mechanisms of intestinal fibrosis.World J. Gastroenterol. 2012; 18: 3635-3661Crossref PubMed Scopus (183) Google Scholar). In addition to the ECM, activated myofibroblasts produce type I and III collagens, mucopolysaccharides, remodeling enzymes such as matrix metalloproteinases (MMPs), and profibrotic cytokines such as transforming growth factor-β1 (TGF-β1) (10Johnson L.A. Rodansky E.S. Sauder K.L. Horowitz J.C. Mih J.D. Tschumperlin D.J. Higgins P.D. Matrix stiffness corresponding to strictured bowel induces a fibrogenic response in human colonic fibroblasts.Inflamm. Bowel Dis. 2013; 19: 891-903Crossref PubMed Scopus (105) Google Scholar). In chronic dextran sulfate sodium (DSS)-induced murine colitis, profibrotic genes such as alpha smooth muscle actin (α-SMA), Collagen I, MMP-9, and connective tissue growth factor (CTGF) (11Holvoet T. Devriese S. Castermans K. Boland S. Leysen D. Vandewynckel Y.P. Devisscher L. Van den Bossche L. Van Welden S. Dullaers M. Vandenbroucke R.E. De Rycke R. Geboes K. Bourin A. Defert O. et al.Treatment of intestinal fibrosis in experimental inflammatory bowel disease by the pleiotropic actions of a local rho kinase inhibitor.Gastroenterology. 2017; 153: 1054-1067Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar) are abundantly activated, and activated myofibroblasts originate from various sources during fibrogenesis (12Scheibe K. Backert I. Wirtz S. Hueber A. Schett G. Vieth M. Probst H.C. Bopp T. Neurath M.F. Neufert C. IL-36R signalling activates intestinal epithelial cells and fibroblasts and promotes mucosal healing in vivo.Gut. 2017; 66: 823-838Crossref PubMed Scopus (110) Google Scholar, 13Lenti M.V. Di Sabatino A. Intestinal fibrosis.Mol. Aspects Med. 2019; 65: 100-109Crossref PubMed Scopus (53) Google Scholar). In addition, epithelial–mesenchymal transition (EMT) is an important hallmark of fibrogenesis (14Jiang H. Shen J. Ran Z. Epithelial-mesenchymal transition in Crohn's disease.Mucosal Immunol. 2018; 11: 294-303Crossref PubMed Scopus (24) Google Scholar), through which epithelial cells lose their polarized epithelial phenotype and transform into mesenchymal cells, including myofibroblasts (13Lenti M.V. Di Sabatino A. Intestinal fibrosis.Mol. Aspects Med. 2019; 65: 100-109Crossref PubMed Scopus (53) Google Scholar, 15Scharl M. Huber N. Lang S. Furst A. Jehle E. Rogler G. Hallmarks of epithelial to mesenchymal transition are detectable in Crohn's disease associated intestinal fibrosis.Clin. Transl. Med. 2015; 4: 1Crossref PubMed Google Scholar). As reported, sustained TGF-β1 upregulation was found in the intestinal fibrotic areas of patients with CD with elevated levels of EMT-related transcription factors (15Scharl M. Huber N. Lang S. Furst A. Jehle E. Rogler G. Hallmarks of epithelial to mesenchymal transition are detectable in Crohn's disease associated intestinal fibrosis.Clin. Transl. Med. 2015; 4: 1Crossref PubMed Google Scholar). However, the mechanism of EMT in the pathogenesis of intestinal stricture is not fully understood. The vitamin D receptor (VDR) is a member of the steroid receptor family and a vital regulator of skeletal health and calcium and phosphorus homeostasis (16Margolis R.N. Christakos S. The nuclear receptor superfamily of steroid hormones and vitamin D gene regulation. An update.Ann. N. Y. Acad. Sci. 2010; 1192: 208-214Crossref PubMed Scopus (53) Google Scholar). The VDR forms a VDR–retinoid X receptor heterodimeric complex and then binds to specific DNA sequences after being activated by 1,25(OH)2D3 (17Christakos S. Dhawan P. Verstuyf A. Verlinden L. Carmeliet G. Vitamin D: Metabolism, molecular mechanism of action, and pleiotropic effects.Physiol. Rev. 2016; 96: 365-408Crossref PubMed Scopus (959) Google Scholar). The inhibitory effects of vitamin D (VD) and the VDR on acute colitis have been reported previously (18He L. Liu T. Shi Y. Tian F. Hu H. Deb D.K. Chen Y. Bissonnette M. Li Y.C. Gut epithelial vitamin D receptor regulates microbiota-dependent mucosal inflammation by suppressing intestinal epithelial cell apoptosis.Endocrinology. 2018; 159: 967-979Crossref PubMed Scopus (63) Google Scholar, 19Liu W. Chen Y. Golan M.A. Annunziata M.L. Du J. Dougherty U. Kong J. Musch M. Huang Y. Pekow J. Zheng C. Bissonnette M. Hanauer S.B. Li Y.C. Intestinal epithelial vitamin D receptor signaling inhibits experimental colitis.J. Clin. Invest. 2013; 123: 3983-3996Crossref PubMed Scopus (243) Google Scholar, 20Li C. Chen Y. Zhu H. Zhang X. Han L. Zhao Z. Wang J. Ning L. Zhou W. Lu C. Xu L. Sang J. Feng Z. Zhang Y. Lou X. et al.Inhibition of histone deacetylation by MS-275 alleviates colitis by activating the vitamin D receptor.J. Crohns Colitis. 2020; 14: 1103-1118Crossref PubMed Scopus (9) Google Scholar), but the potential effect of the VDR on intestinal fibrosis is currently poorly understood. Previous studies reported diminished VDR protein levels in the intestines of patients with CD compared with control tissues (21Gisbert-Ferrandiz L. Cosin-Roger J. Hernandez C. Macias-Ceja D.C. Ortiz-Masia D. Salvador P. Esplugues J.V. Hinojosa J. Navarro F. Calatayud S. Barrachina M.D. Diminished vitamin D receptor protein levels in Crohn's disease fibroblasts: Effects of vitamin D.Nutrients. 2020; 12: 973Crossref Scopus (5) Google Scholar). In addition, a VD-deficient diet downregulated VDR expression and promoted chronic 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced intestinal fibrosis (22Tao Q. Wang B. Zheng Y. Jiang X. Pan Z. Ren J. Vitamin D prevents the intestinal fibrosis via induction of vitamin D receptor and inhibition of transforming growth factor-beta1/Smad3 pathway.Dig. Dis. Sci. 2015; 60: 868-875Crossref PubMed Scopus (40) Google Scholar). Knocking down the VDR facilitated the expression of α-SMA and collagen I in colonic subepithelial myofibroblasts through the TGF-β1/Smad3 pathway (22Tao Q. Wang B. Zheng Y. Jiang X. Pan Z. Ren J. Vitamin D prevents the intestinal fibrosis via induction of vitamin D receptor and inhibition of transforming growth factor-beta1/Smad3 pathway.Dig. Dis. Sci. 2015; 60: 868-875Crossref PubMed Scopus (40) Google Scholar). Based on this evidence, we hypothesized that the VDR might have an inhibitory effect on intestinal fibrosis. The VDR plays an essential role in the mitochondrial respiratory process (23Consiglio M. Destefanis M. Morena D. Foglizzo V. Forneris M. Pescarmona G. Silvagno F. The vitamin D receptor inhibits the respiratory chain, contributing to the metabolic switch that is essential for cancer cell proliferation.PLoS One. 2014; 9e115816Crossref PubMed Scopus (46) Google Scholar). As reported, the VDR has an essential biosynthetic function in the mitochondrial respiratory chain activity and facilitates the energy-producing tricarboxylic acid cycle during cellular proliferation (23Consiglio M. Destefanis M. Morena D. Foglizzo V. Forneris M. Pescarmona G. Silvagno F. The vitamin D receptor inhibits the respiratory chain, contributing to the metabolic switch that is essential for cancer cell proliferation.PLoS One. 2014; 9e115816Crossref PubMed Scopus (46) Google Scholar). In a human epidermal keratinocyte cell line, VDR ablation increased the production of reactive oxygen species (ROS), resulting in cellular damage, the loss of mitochondrial integrity, and even apoptotic death in a long-term observation study (24Ricca C. Aillon A. Bergandi L. Alotto D. Castagnoli C. Silvagno F. Vitamin D receptor is necessary for mitochondrial function and cell health.Int. J. Mol. Sci. 2018; 19: 1672Crossref Scopus (77) Google Scholar). In contrast, VD treatment inhibited oxidative stress and mitochondrial dynamics in C2C12 muscle cells (25Chang E. 1,25-Dihydroxyvitamin D decreases tertiary butyl-hydrogen peroxide-induced oxidative stress and increases AMPK/SIRT1 activation in C2C12 muscle cells.Molecules. 2019; 24: 3903Crossref Scopus (23) Google Scholar). However, there are currently no reports about VDR-mediated regulation of mitochondrial function in CD-induced intestinal fibrosis. Given these results, we hypothesized that the VDR was a vital modulator of intestinal fibrosis by regulating mitochondrial functions. The aim of this study was to investigate the effect of the VDR on the pathogenesis of intestinal fibrosis. To this end, we established two classic mouse models of intestinal fibrosis: intestinal epithelium–specific VDR KO and VD dietary intervention. In addition, we used CCD-18Co and human primary colonic fibroblasts to examine the effect of the VDR on fibroblast activation and HT29 cells to explore potential EMT mechanisms. Furthermore, CD intestinal tissues were collected to verify clinical significance. We hypothesized that in the absence of the VDR, fibroblasts could be activated, during which mitochondrial dysfunction would occur in the epithelium, disrupt barrier integrity, and consequently promote EMT and ECM deposition. This mitochondria-dependent VDR/EMT pathway suggests a previously unrecognized mechanism of intestinal fibrogenesis and a novel strategy for antifibrotic therapies. To examine the role of the VDR in intestinal fibrosis, we obtained colonic tissues from both stenotic areas and nonstenotic control areas from the same patients with CD. H&E staining revealed significant broadening of the mucosa, submucosa, and even muscularis in stenotic areas compared with nonstenotic areas (Fig. 1A). Quantification of Masson’s trichrome staining showed massive collagen deposition in the submucosa and mucosa of stenotic areas (Fig. 1, A and B). Strikingly, quantitative PCR analysis of colonic tissues from patients with CD showed increased expression of various fibrosis markers in stenotic areas, including a myofibroblast marker (α-SMA), ECM markers (fibronectin, type I collagen, and CTGF), and MMP-2 and MMP-9 (Fig. 1C). In CD colonic tissues, downregulation of the VDR in stenotic areas was observed, as indicated by immunohistochemistry (IHC) staining, and these results were further confirmed at the mRNA and protein levels (Fig. 1, D–F). In addition, in intestinal fibrosis mouse models, VDR expression was dramatically decreased in the intestines in both chronic DSS–induced mice and chronic TNBS–induced mice (Fig. 1, G and H). Thus, our data indicated enhanced ECM deposition in fibrotic intestinal tissues, accompanied by a significant decrease in VDR expression. To further explore the specific role of the intestinal VDR in the pathogenesis of intestinal fibrosis, we generated intestine-specific VDR-KO (VDRIEC-KO) mice, and their littermate VDRfl/fl mice (flox) were used as controls (Fig. S1A). Repetitive administration of 2% DSS was used to mimic CD-induced intestinal fibrosis. In VDRIEC-KO mice, complete knockdown of VDR expression in colon tissues was confirmed at both the mRNA and protein levels (Fig. 2, D and E). During DSS administration, VDRIEC-KO mice showed a significantly higher body weight loss than VDRfl/fl mice beginning on day 36 (Fig. 2A). In addition, the VDRIEC-KO group was more sensitive to DSS administration, as indicated by a higher death rate and more severe colonic obstruction than those of the VDRfl/fl control group (Fig. S1, B and D), although the colon lengths were similar in the two groups (Fig. S2C). In addition, epithelium-specific knockdown of the VDR increased collagen deposition (Fig. 2B) and resulted in higher fibrosis and inflammation scores (Fig. 2C). Quantitative PCR analysis of the colonic tissues of DSS-induced mice revealed increased expression of fibrosis markers, including fibronectin, MMP-9 and TIMP-1, and inflammation markers, including interleukin-6 and chemokine (C-X-C motif) ligand (Fig. 2F). Although collagen I, TGF-β1, and MMP-2 only showed an increasing trend after chronic DSS administration, these factors were significantly increased in DSS-induced VDRIEC-KO mice compared with mice in the VDRfl/fl DSS group (Fig. 2F, Fig. S1E). In addition, Western blot analysis confirmed the activation of the classic TGF-β1 signaling pathway and ECM deposition, especially in VDRIEC-KO DSS mice (Fig. 2F). These findings suggested that VDR KO in the intestinal epithelium exacerbated chronic DSS-induced intestinal fibrosis and inflammation in mice. As TNBS administration is a well-recognized approach to mimic colitis induced by the immune response, we verified the effect of the VDR on chronic TNBS-induced intestinal fibrosis. Repetitive administration of TNBS caused high death rates. The survival rate of the VDRIEC-KO TNBS group was 57.1%, while that of the VDRfl/fl TNBS group was 66.7% (Fig. 2G). The colon lengths in the two TNBS groups were not different (Fig. S1F). In addition, treatment with TNBS in epithelium-specific VDR-knockdown mice resulted in an histological grade and exacerbated intestinal inflammation and ECM deposition (Fig. 2, H and I). Chronic TNBS administration caused a dramatic decrease in VDR expression (Fig. 2, J and K). Western blot analysis revealed that VDR KO in the epithelium increased the expression of fibronectin, MMP-9, and TGF-β1 after 6 weeks of TNBS administration (Fig. 3J). The increased mRNA levels of these genes also indicated that the VDR KO was an exacerbating factor in TNBS-induced fibrosis (Fig. 2K, Fig. S1G). In addition, we found that vimentin expression was increased, accompanied by decreased expression of zonulin-1 (ZO-1) and E-cadherin, which indicated increased activation of the EMT process in VDRIEC-KO TNBS mice (Fig. 3J). These results showed that the intestinal epithelium–specific VDR KO exacerbated TNBS-induced intestinal fibrosis and EMT. Previous studies reported that repeated TNBS administration increased intestinal inflammation and fibrosis in mice fed a VD-deficient diet, whereas a VD-sufficient diet alleviated fibrosis by inhibiting TGF-β1/Smad3 signal transduction (22Tao Q. Wang B. Zheng Y. Jiang X. Pan Z. Ren J. Vitamin D prevents the intestinal fibrosis via induction of vitamin D receptor and inhibition of transforming growth factor-beta1/Smad3 pathway.Dig. Dis. Sci. 2015; 60: 868-875Crossref PubMed Scopus (40) Google Scholar). However, the effect VD dietary intervention on chronic DSS-induced fibrosis mouse models is unknown, considering the different pathogeneses associated with TNBS and DSS administration. Thus, we investigated the effect of VD intervention on intestinal fibrosis. Male C57BL/6 mice were given a VD-deficient diet or VD-supplemented diet before 3 weeks of repeated DSS administration (Fig. 3A). DSS administration induced obvious body weight loss, especially in the VD-deficient group (Fig. S2A). The survival rate of the VD-deficient DSS group was only 33.3%, while that of the VD-supplemented DSS group, especially the VD4000U group, increased to 87.5% (Fig. 3B). In addition, morphologically, the VD-deficient group showed worsened hematochezia, edema, and stiffness, although there was no statistically significant difference in the colon length between the DSS groups (Fig. 3C, Fig. S2B). Feeding DSS-induced mice a VD-deficient diet exacerbated chronic inflammation and fibrosis (Fig. 3, D and E), whereas in the VD-supplemented group, fibrosis and inflammation were highly improved compared with those in the normal-diet group (Fig. 3, D and E). In addition, tissue IHC staining and immunofluorescence staining revealed that the VD-deficient diet increased ECM deposition and fibroblast activation, whereas the VD-supplemented diet showed inhibitory effects (Fig. 3D). Furthermore, VD dietary intervention modulated the serum levels of VD and influenced the expression of the VDR in intestinal tissues (Fig. 3, F and G). The mRNA levels of α-SMA and fibronectin also indicated that the VD-deficient diet exacerbated DSS-induced fibrosis and chronic inflammation, whereas the VD4000U supplementary diet alleviated symptoms (Fig. 3H, Fig. S2C). Therefore, VD dietary intervention regulated the development of intestinal fibrosis by modulating the intestinal expression of the VDR. Intestinal fibrosis is characterized by abnormal tissue repair and the massive deposition of ECM proteins, which are produced by activated myofibroblasts (26Gordon I.O. Agrawal N. Goldblum J.R. Fiocchi C. Rieder F. Fibrosis in ulcerative colitis: Mechanisms, features, and consequences of a neglected problem.Inflamm. Bowel Dis. 2014; 20: 2198-2206Crossref PubMed Scopus (80) Google Scholar). To investigate the effect of the VDR on the activation of fibroblasts, we purchased human colon fibroblasts (CCD-18Co cells) from the American Type Culture Collection and purified and cultured primary human intestinal fibroblasts. First, we used VD to activate VDR signaling and mimic the biological functions of VD (Fig. 4C; Fig. S3, A and B). We found an increase in the number of α-SMA–positive CCD-18Co cells after treatment with TGF-β1 for 48 h (Fig. 4A). The number of α-SMA–positive cells was decreased in the VD pretreatment group (Fig. 4A). At the transcriptional level, VD pretreatment significantly decreased α-SMA expression after CCD-18Co cells were activated with TGF-β1 (Fig. 4B). In primary human intestinal fibroblasts, VD dramatically decreased the expression of α-SMA and fibronectin, which were stimulated by TGF-β1 (Fig. 4C). Then, we used calcitriol to pharmacologically activate the VDR. In CCD-18Co cells, although calcitriol could slightly increase the expression of the VDR, fibronectin and CTGF were decreased by calcitriol treatment (Fig. S3C). Flow cytometric analysis showed that the fibroblast activation marker α-SMA was significantly decreased by calcitriol in the presence of TGF-β1 (Fig. 4D). In primary human intestinal fibroblasts, calcitriol significantly increased the expression of the VDR and dramatically decreased α-SMA and fibronectin expression in the presence of TGF-β1 stimulation (Fig. 4, E and F). Furthermore, VDR overexpression by Flag-tagged VDR plasmid transfection significantly increased VDR expression and alleviated α-SMA expression in CCD-18Co cells (Fig. 4G, Fig. S3D). In addition, VDR overexpression inhibited fibrosis markers induced by TGF-β1 stimulation in primary human intestinal fibroblasts, including α-SMA, fibronectin, CTGF, MMP-9, and TGF-β/Smad pathway factors (Fig. 4, H and I). Moreover, we identified the VDR exerted its effects in the presence of the VD ligand (Fig. S3E). Therefore, pharmacological stimulation of the VDR and overexpression of the VDR both inhibited the increase in fibrosis markers and fibroblast activation. These results indicated that the VDR gene had an inhibitory effect on fibroblast activation. A loss-of-function experiment was performed for further investigation. We found that siRNA-mediated knockdown of the VDR significantly exacerbated TGF-β1-induced fibroblast activation and ECM deposition in primary human intestinal fibroblasts (Fig. 4, J and K). Furthermore, TGF-β1 expression was increased in the VDR-knockdown group, combined with the upregulation of p-smad2 and p-smad3, suggesting activated TGF-β1–Smad signaling in VDR-deficient fibroblasts (Fig. 4K). Therefore, activated fibroblasts promoted intestinal fibrosis. Taken together, these findings indicated that knocking down the VDR exacerbated primary human intestinal fibroblast activation. As reported, the gut epithelial VDR inhibited colitis by protecting the mucosal epithelial barrier and maintaining mucosal integrity (19Liu W. Chen Y. Golan M.A. Annunziata M.L. Du J. Dougherty U. Kong J. Musch M. Huang Y. Pekow J. Zheng C. Bissonnette M. Hanauer S.B. Li Y.C. Intestinal epithelial vitamin D receptor signaling inhibits experimental colitis.J. Clin. Invest. 2013; 123: 3983-3996Crossref PubMed Scopus (243) Google Scholar, 20Li C. Chen Y. Zhu H. Zhang X. Han L. Zhao Z. Wang J. Ning L. Zhou W. Lu C. Xu L. Sang J. Feng Z. Zhang Y. Lou X. et al.Inhibition of histone deacetylation by MS-275 alleviates colitis by activating the vitamin D receptor.J. Crohns Colitis. 2020; 14: 1103-1118Crossref PubMed Scopus (9) Google Scholar), although only a few studies illustrated the mechanism of this protective effect against colitis. Here, we found that VDR KO in the intestinal epithelium suppressed mucosal absorptive function in vivo (Fig. 5A). We isolated epithelial layers from both VDR-KO mice and control mice after repeated DSS administration. We found that the expression levels of E-cadherin, ZO-1, and β-catenin, the most representative markers of the epithelial barrier function, were significantly decreased in VDR-KO mice, especially after DSS administration (Fig. 5, B and C). Considering that the downregulation of epithelial markers is related to EMT, which is one of the main sources of mesenchymal fibroblasts, EMT was promoted in VDR-KO mice. In addition, the expression levels of epithelial markers, including E-cadherin, ZO-1, and β-catenin, were significantly decreased in mice with DSS-induced chronic intestinal fibrosis, whereas the expression levels of mesenchymal markers, including vimentin and Slug, were increased, indicating that EMT is a vital process in intestinal fibrosis (Fig. S4, A and B). Therefore, we further explored the relationship between intestinal epithelial VDR expression and EMT in fibrosis. We evaluated the effects of the VDR gene on the human intestinal epithelial tumor cell line HT29 by establishing a well-characterized model of TGF-β1-induced EMT (27Ortiz-Masia D. Salvador P. Macias-Ceja D.C. Gisbert-Ferrandiz L. Esplugues J.V. Manye J. Alos R. Navarro-Vicente F. Mamie C. Scharl M. Cosin-Roger J. Calatayud S. Barrachina M.D. WNT2b activates epithelial-mesenchymal transition through FZD4: Relevance in penetrating Crohn s disease.J. Crohns Colitis. 2020; 14: 230-239Crossref PubMed Scopus (20) Google Scholar, 28Ortiz-Masia D. Gisbert-Ferrandiz L. Bauset C. Coll S. Mamie C. Scharl M. Esplugues J.V. Alos R. Navarro F. Cosin-Roger J. Barrachina M.D. Calatayud S. Succinate activates EMT in intestinal epithelial cells through SUCNR1: A novel protagonist in fistula development.Cells. 2020; 9: 1104Crossref Scopus (19) Google Scholar). In HT29 cells, knockdown of VDR expression decreased epithelial integrity (Fig. 5D; Fig. S5A). When we activated EMT by administering TGF-β1 to HT29 cells, mesenchymal markers were dramatically elevated in the VDR-deficient group (Fig. 5E). In addition, VDR overexpression significantly alleviated the expression of Vimentin and Zeb1, while elevating the expression of epithelial markers such as E-cadherin, ZO-1, and claudin-1 (Fig. 5F; Fig. S5B). Similar results were observed after the pharmacological stimulation of the VDR (Fig. 5G; Fig. S5C). Taken together, these results indicated that the VDR could mediate epithelial integrity and inhibit intestinal fibrosis through modulating EMT. Mitochondrial morphological changes were analyzed by electron microscopy. We found that the intestinal epithelial cells in VDRIEC-KO mice exhibited mitochondrial swelling, vesicular formation, and villus disruption compared with those of VDRfl/fl mice (Fig. 6A). In addition, in the intestinal mesenchyme of VDRIEC-KO mice, the ECM greatly accumulated in the" @default.
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• W3134265951 title "Vitamin D receptor inhibits EMT via regulation of the epithelial mitochondrial function in intestinal fibrosis" @default.
• W3134265951 cites W1486312415 @default.
• W3134265951 cites W1547943993 @default.
• W3134265951 cites W1570973990 @default.
• W3134265951 cites W1966642918 @default.
• W3134265951 cites W1973859913 @default.
• W3134265951 cites W1980090229 @default.
• W3134265951 cites W1988156447 @default.
• W3134265951 cites W1989851827 @default.
• W3134265951 cites W1998176709 @default.
• W3134265951 cites W2016347137 @default.
• W3134265951 cites W2025449918 @default.
• W3134265951 cites W2030699054 @default.
• W3134265951 cites W2037478126 @default.
• W3134265951 cites W2038621270 @default.
• W3134265951 cites W2061708494 @default.
• W3134265951 cites W2063628403 @default.
• W3134265951 cites W2065915608 @default.
• W3134265951 cites W20726012 @default.
• W3134265951 cites W2088826436 @default.
• W3134265951 cites W2093648126 @default.
• W3134265951 cites W2099348711 @default.
• W3134265951 cites W2101826917 @default.
• W3134265951 cites W2113690494 @default.
• W3134265951 cites W2116306687 @default.
• W3134265951 cites W2138153315 @default.
• W3134265951 cites W2144378498 @default.
• W3134265951 cites W2154570785 @default.
• W3134265951 cites W2157334943 @default.
• W3134265951 cites W2171765303 @default.
• W3134265951 cites W2179748167 @default.
• W3134265951 cites W2254563264 @default.
• W3134265951 cites W2302437989 @default.
• W3134265951 cites W2313203176 @default.
• W3134265951 cites W2324113947 @default.
• W3134265951 cites W2395369917 @default.
• W3134265951 cites W2530437302 @default.
• W3134265951 cites W2552754421 @default.
• W3134265951 cites W2593499806 @default.
• W3134265951 cites W2620756707 @default.
• W3134265951 cites W2694013831 @default.
• W3134265951 cites W2733951407 @default.
• W3134265951 cites W2773928224 @default.
• W3134265951 cites W2777199658 @default.
• W3134265951 cites W2805842931 @default.
• W3134265951 cites W2890049521 @default.
• W3134265951 cites W2901155911 @default.
• W3134265951 cites W2944155224 @default.
• W3134265951 cites W2954078140 @default.
• W3134265951 cites W2966443595 @default.
• W3134265951 cites W2970747576 @default.
• W3134265951 cites W2982623967 @default.
• W3134265951 cites W2996612201 @default.
• W3134265951 cites W3005228000 @default.
• W3134265951 cites W3006268959 @default.
• W3134265951 cites W3006915800 @default.
• W3134265951 cites W3015102222 @default.
• W3134265951 cites W3021611934 @default.
• W3134265951 cites W3048519515 @default.
• W3134265951 cites W4211153467 @default.
• W3134265951 doi "https://doi.org/10.1016/j.jbc.2021.100531" @default.
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