scholarly journals Deoxycholic Acid Modulates Cell-Junction Gene Expression and Increases Intestinal Barrier Dysfunction in Caco-2 Cell Monolayers

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 956-956
Author(s):  
Huawei Zeng ◽  
Bryan Safratowich ◽  
Wen-Hsing Cheng ◽  
Kate Claycombe-Larson ◽  
Mary Briske-Anderson

Abstract Objectives Diet-related obesity is associated with an increased risk of developing intestinal hyperpermeability. High dietary fat intake causes an increase in colonic bile acids (BAs), particularly deoxycholic acid (DCA, secondary BA), which may disrupt the intestinal epithelial barrier. To determine the potential role of bile acids in barrier dysfunction, we hypothesize that DCA modulates the gene expression in multiple cell junction pathways and increases intestinal permeability. Methods With a Caco-2 cell intestinal barrier model, we used cell proliferation, PCR array, biochemical, western blotting and immunofluorescent assays to examine the impact of DCA on the integrity of intestinal barrier and gene expression. Results Human intestinal Caco-2 cells were grown in monolayers and challenged with DCA at physiological concentrations (sub mM levels). DCA increased transcellular and paracellular permeability (>30%) via transepithelial electrical resistance and phenol red flux measurements. Similarly, DCA increased intracellular reactive oxidative species production (>1-fold) and accompanied a modification of cellular p38 and ERK1/2 signaling pathways. Further characterization of underlying genes related to epithelial barrier with PCR array analysis identified that 23 genes (in tight junction, focal adhesion, gap junction and adhere junction pathways) were decreased at least 40% in (0.25 mM) DCA-treated Caco-2 cells when compared to untreated cells. Finally, we demonstrated that DCA decreased the protein levels of occludin gene at both cellular tight junction and nucleus in epithelial cells. Conclusions Collectively, our data suggest that at physiological concentrations, DCA alters the gene expression of multiple pathways related to cell junctions and increases permeability in a Caco-2 intestinal barrier model. These molecular events may represent the underlying mechanistic pathways that are responsible for DCA-induced transcellular and paracellular permeation. Funding Sources This work was supported by U.S. Department of Agriculture, Agricultural Research Service, research project 3062-51,000-056–00D.

2010 ◽  
Vol 298 (5) ◽  
pp. G625-G633 ◽  
Author(s):  
Wei Zhong ◽  
Craig J. McClain ◽  
Matthew Cave ◽  
Y. James Kang ◽  
Zhanxiang Zhou

Disruption of the intestinal barrier is a causal factor in the development of alcoholic endotoxemia and hepatitis. This study was undertaken to determine whether zinc deficiency is related to the deleterious effects of alcohol on the intestinal barrier. Mice were pair fed an alcohol or isocaloric liquid diet for 4 wk, and hepatitis was detected in association with elevated blood endotoxin level. Alcohol exposure significantly increased the permeability of the ileum but did not affect the barrier function of the duodenum or jejunum. Reduction of tight-junction proteins at the ileal epithelium was detected in alcohol-fed mice although alcohol exposure did not cause apparent histopathological changes. Alcohol exposure significantly reduced the ileal zinc concentration in association with accumulation of reactive oxygen species. Caco-2 cell culture demonstrated that alcohol exposure increases the intracellular free zinc because of oxidative stress. Zinc deprivation caused epithelial barrier disruption in association with disassembling of tight junction proteins in the Caco-2 monolayer cells. Furthermore, minor zinc deprivation exaggerated the deleterious effect of alcohol on the epithelial barrier. In conclusion, epithelial barrier dysfunction in the distal small intestine plays an important role in alcohol-induced gut leakiness, and zinc deficiency attributable to oxidative stress may interfere with the intestinal barrier function by a direct action on tight junction proteins or by sensitizing to the effects of alcohol.


Amino Acids ◽  
2021 ◽  
Author(s):  
Tatsuya Hasegawa ◽  
Ami Mizugaki ◽  
Yoshiko Inoue ◽  
Hiroyuki Kato ◽  
Hitoshi Murakami

AbstractIntestinal oxidative stress produces pro-inflammatory cytokines, which increase tight junction (TJ) permeability, leading to intestinal and systemic inflammation. Cystine (Cys2) is a substrate of glutathione (GSH) and inhibits inflammation, however, it is unclear whether Cys2 locally improves intestinal barrier dysfunction. Thus, we investigated the local effects of Cys2 on oxidative stress-induced TJ permeability and intestinal inflammatory responses. Caco-2 cells were cultured in a Cys2-supplemented medium for 24 h and then treated with H2O2 for 2 h. We assessed TJ permeability by measuring transepithelial electrical resistance and the paracellular flux of fluorescein isothiocyanate–dextran 4 kDa. We measured the concentration of Cys2 and GSH after Cys2 pretreatment. The mRNA expression of pro-inflammatory cytokines was assessed. In addition, the levels of TJ proteins were assessed by measuring the expression of TJ proteins in the whole cells and the ratio of TJ proteins in the detergent-insoluble fractions to soluble fractions (IS/S ratio). Cys2 treatment reduced H2O2-induced TJ permeability. Cys2 did not change the expression of TJ proteins in the whole cells, however, suppressed the IS/S ratio of claudin-4. Intercellular levels of Cys2 and GSH significantly increased in cells treated with Cys2. Cys2 treatment suppressed the mRNA expression of pro-inflammatory cytokines, and the mRNA levels were significantly correlated with TJ permeability. In conclusion, Cys2 treatment locally reduced oxidative stress-induced intestinal barrier dysfunction possively due to the mitigation of claudin-4 dislocalization. Furthermore, the effect of Cys2 on the improvement of intestinal barrier function is related to the local suppression of oxidative stress-induced pro-inflammatory responses.


Nutrients ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 3515
Author(s):  
Pingting Guo ◽  
Haichao Wang ◽  
Linbao Ji ◽  
Peixia Song ◽  
Xi Ma

The metabolic disorder caused by excessive fructose intake was reported extensively and often accompanied by intestinal barrier dysfunction. And the rising dietary fructose was consumed at an early age of human. However, related researches were almost conducted in rodent models, while in the anatomy and physiology of gastrointestinal tract, pig is more similar to human beings than rodents. Hence, weaned piglets were chosen as the model animals in our study to investigate the fructose’s impacts on intestinal tight junction, inflammation response and microbiota structure of piglets. Herein, growth performance, inflammatory response, oxidation resistance and ileal and colonic microbiota of piglet were detected after 35-day fructose supplementation. Our results showed decreased tight junction gene expressions in piglets after fructose addition, with no obvious changes in the growth performance, antioxidant resistance and inflammatory response. Moreover, fructose supplementation differently modified the microbiota structures in ileum and colon. In ileum, the proportions of Streptococcus and Faecalibacterium were higher in Fru group (fructose supplementation). In colon, the proportions of Blautia and Clostridium sensu stricto 1 were higher in Fru group. All the results suggested that tight junction dysfunction might be an earlier fructose-induced event than inflammatory response and oxidant stress and that altered microbes in ileum and colon might be the potential candidates to alleviate fructose-induced intestinal permeability alteration.


2020 ◽  
Vol 11 (9) ◽  
pp. 8077-8088
Author(s):  
Zhenxia Xu ◽  
Wenchao Chen ◽  
Qianchun Deng ◽  
Qingde Huang ◽  
Xu Wang ◽  
...  

Intestinal epithelial barrier dysfunction with dysbiosis of gut microbiota contributes to the occurrence and acceleration of colitis.


Nutrients ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2325 ◽  
Author(s):  
Danielle Cardoso-Silva ◽  
Deborah Delbue ◽  
Alice Itzlinger ◽  
Renée Moerkens ◽  
Sebo Withoff ◽  
...  

Gluten-related disorders include distinct disease entities, namely celiac disease, wheat-associated allergy and non-celiac gluten/wheat sensitivity. Despite having in common the contact of the gastrointestinal mucosa with components of wheat and other cereals as a causative factor, these clinical entities have distinct pathophysiological pathways. In celiac disease, a T-cell mediate immune reaction triggered by gluten ingestion is central in the pathogenesis of the enteropathy, while wheat allergy develops as a rapid immunoglobulin E- or non-immunoglobulin E-mediated immune response. In non-celiac wheat sensitivity, classical adaptive immune responses are not involved. Instead, recent research has revealed that an innate immune response to a yet-to-be-defined antigen, as well as the gut microbiota, are pivotal in the development in this disorder. Although impairment of the epithelial barrier has been described in all three clinical conditions, its role as a potential pathogenetic co-factor, specifically in celiac disease and non-celiac wheat sensitivity, is still a matter of investigation. This article gives a short overview of the mucosal barrier of the small intestine, summarizes the aspects of barrier dysfunction observed in all three gluten-related disorders and reviews literature data in favor of a primary involvement of the epithelial barrier in the development of celiac disease and non-celiac wheat sensitivity.


2016 ◽  
Vol 310 (1) ◽  
pp. C54-C65 ◽  
Author(s):  
Ting-Xi Yu ◽  
Bei-Lin Gu ◽  
Jun-Kai Yan ◽  
Jie Zhu ◽  
Wei-Hui Yan ◽  
...  

The effectiveness and stability of epithelial barrier depend on apical junctional complexes, which consist of tight junctions (TJs) and adherens junctions (AJs). E-cadherin is the primary component of AJs, and it is essential for maintenance of cell-to-cell interactions and regulates the epithelial barrier. However, the exact mechanism underlying E-cadherin expression, particularly at the posttranscriptional level, remains largely unknown. RNA-binding proteins CUG-binding protein 1 (CUGBP1) and HU antigen R (HuR) are highly expressed in the intestinal epithelial tissues and modulate the stability and translation of target mRNAs. Here, we present evidence that CUGBP1 and HuR interact directly with the 3′-untranslated region of E-cadherin mRNA and regulate E-cadherin translation. CUGBP1 overexpression in Caco-2 cells inhibited E-cadherin translation by increasing the recruitment of E-cadherin mRNA to processing bodies (PBs), thus resulting in an increase in paracellular permeability. Overexpression of HuR exhibited an opposite effect on E-cadherin expression by preventing the translocation of E-cadherin mRNA to PBs and therefore prevented CUGBP1-induced repression of E-cadherin expression. Elevation of HuR also abolished the CUGBP1-induced epithelial barrier dysfunction. These findings indicate that CUGBP1 and HuR negate each other's effects in regulating E-cadherin translation by altering the recruitment of E-cadherin mRNA to PBs and play an important role in the regulation of intestinal barrier integrity under various pathophysiological conditions.


2013 ◽  
Vol 304 (11) ◽  
pp. G970-G979 ◽  
Author(s):  
Andreas Fischer ◽  
Markus Gluth ◽  
Ulrich-Frank Pape ◽  
Bertram Wiedenmann ◽  
Franz Theuring ◽  
...  

Intestinal barrier dysfunction is pivotal in the etiology of inflammatory bowel diseases. Combined clinical and endoscopic remission (“mucosal healing”) in patients who received anti-TNF-α therapies suggests restitution of the intestinal barrier, but the mechanisms involved are largely unknown. We therefore investigated the impact of the anti-TNF-α antibody adalimumab on barrier function in two in vitro models. Combined stimulation of Caco-2 and T-84 cells with interferon-γ and TNF-α resulted in a significant decrease of transepithelial electrical resistance (TEER) within 6 h that was prevented by adalimumab in concentrations down to 100 ng/ml. Adalimumab furthermore antagonized the appearance of irregular membrane undulations and prevented internalization of tight junction proteins upon cytokine exposure. In addition, TNF-α induced a downregulation of claudin-1, claudin-2, claudin-4, and occludin as well as activation of phosphatidylinositol 3-kinase signaling in T-84 but not Caco-2 cells, which was reversed by adalimumab. At the signaling level, adalimumab prevented increased phosphorylation of myosin light chain as well as activation of p38 MAPK and NF-κB accompanying the decline in TEER in both model systems. Pharmacological inhibition of NF-κB signaling partially prevented the TNF-α-induced TEER loss, whereas inhibition of p38 worsened barrier dysfunction in Caco-2 but not T-84 cells. Taken together, these data demonstrate that adalimumab prevents barrier dysfunction induced by TNF-α both functionally and structurally as well as at the level of signal transduction. Barrier protection might therefore constitute a novel mechanism how anti-TNF-α therapy contributes to epithelial restitution and tissue repair in inflammatory bowel diseases.


2019 ◽  
Vol 20 (14) ◽  
pp. 3555 ◽  
Author(s):  
Takayuki Kohno ◽  
Takumi Konno ◽  
Takashi Kojima

Maintaining a robust epithelial barrier requires the accumulation of tight junction proteins, LSR/angulin-1 and tricellulin, at the tricellular contacts. Alterations in the localization of these proteins temporarily cause epithelial barrier dysfunction, which is closely associated with not only physiological differentiation but also cancer progression and metastasis. In normal human endometrial tissues, the endometrial cells undergo repeated proliferation and differentiation under physiological conditions. Recent observations have revealed that the localization and expression of LSR/angulin-1 and tricellulin are altered in a menstrual cycle-dependent manner. Moreover, it has been shown that endometrial cancer progression affects these alterations. This review highlights the differences in the localization and expression of tight junction proteins in normal endometrial cells and endometrial cancers and how they cause functional changes in cells.


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