scholarly journals Occludin regulates macromolecule flux across the intestinal epithelial tight junction barrier

2011 ◽  
Vol 300 (6) ◽  
pp. G1054-G1064 ◽  
Author(s):  
Rana Al-Sadi ◽  
Khaldun Khatib ◽  
Shuhong Guo ◽  
Dongmei Ye ◽  
Moustafa Youssef ◽  
...  
Keyword(s):  
Tight Junction ◽  
Intestinal Permeability ◽  
Transepithelial Resistance ◽  
Intestinal Epithelial ◽  
Knock Down ◽  
Large Channel ◽  
Epithelial Tight Junction ◽  
Mouse Intestine

Defective intestinal epithelial tight junction (TJ) barrier has been shown to be an important pathogenic factor contributing to the development of intestinal inflammation. The expression of occludin is markedly decreased in intestinal permeability disorders, including in Crohn's disease, ulcerative colitis, and celiac disease, suggesting that the decrease in occludin expression may play a role in the increase in intestinal permeability. The purpose of this study was to delineate the involvement of occludin in intestinal epithelial TJ barrier by selective knock down of occludin in in vitro (filter-grown Caco-2 monolayers) and in vivo (recycling perfusion of mouse intestine) intestinal epithelial models. Our results indicated that occludin small-interfering RNA (siRNA) transfection causes an increase in transepithelial flux of various-sized probes, including urea, mannitol, inulin, and dextran, across the Caco-2 monolayers, without affecting the transepithelial resistance. The increase in relative flux rate was progressively greater for larger-sized probes, indicating that occludin depletion has the greatest effect on the flux of large macromolecules. siRNA-induced knock down of occludin in mouse intestine in vivo also caused an increase in intestinal permeability to dextran but did not affect intestinal tissue transepithelial resistance. In conclusion, these results show for the first time that occludin depletion in intestinal epithelial cells in vitro and in vivo leads to a selective or preferential increase in macromolecule flux, suggesting that occludin plays a crucial role in the maintenance of TJ barrier through the large-channel TJ pathway, the pathway responsible for the macromolecule flux.

scholarly journals Layilin is critical for mediating hyaluronan 35 kDa-induced intestinal epithelial tight junction protein ZO-1 in vitro and in vivo

2018 ◽  
Vol 66 ◽  
pp. 93-109 ◽  
Author(s):  
Yeojung Kim ◽  
Gail A. West ◽  
Greeshma Ray ◽  
Sean P. Kessler ◽  
Aaron C. Petrey ◽  
...  
Keyword(s):  
Tight Junction ◽  
Tight Junction Protein ◽  
Intestinal Epithelial ◽  
Junction Protein ◽  
Epithelial Tight Junction

MMP-9 Modulation of Intestinal Epithelial Tight Junction Barrier In-Vitro and In-Vivo is Mediated by Myosin Light Chain Kianse (MLCK)

2017 ◽  
Vol 152 (5) ◽  
pp. S559 ◽  
Author(s):  
Rana Al-Sadi ◽  
Manmeet Rawat ◽  
Thomas Y. Ma
Keyword(s):  
Tight Junction ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Intestinal Epithelial ◽  
Epithelial Tight Junction

Regulation of human epithelial tight junction proteins by Lactobacillus plantarum in vivo and protective effects on the epithelial barrier

2010 ◽  
Vol 298 (6) ◽  
pp. G851-G859 ◽  
Author(s):  
Jurgen Karczewski ◽  
Freddy J. Troost ◽  
Irene Konings ◽  
Jan Dekker ◽  
Michiel Kleerebezem ◽  
...  
Keyword(s):  
Tight Junction ◽  
Lactobacillus Plantarum ◽  
Transmembrane Protein ◽  
Intestinal Barrier ◽  
Protective Effects ◽  
Epithelial Tight Junction ◽  
Vitro Model ◽  
Probiotic Mechanisms

Lactobacillus plantarum , a commensal bacterium of humans, has been proposed to enhance the intestinal barrier, which is compromised in a number of intestinal disorders. To study the effect of L. plantarum strain WCFS1 on human barrier function, healthy subjects were administered L. plantarum or placebo in the duodenum for 6 h by means of a feeding catheter. The scaffold protein zonula occludens (ZO)-1 and transmembrane protein occludin were found to be significantly increased in the vicinity of the tight-junction (TJ) structures, which form the paracellular seal between cells of the epithelium. In an in vitro model of the human epithelium, L. plantarum induced translocation of ZO-1 to the TJ region; however, the effects on occludin were minor compared with those seen in vivo. L. plantarum was shown to activate Toll-like receptor 2 (TLR2) signaling, and treatment of Caco-2 monolayers with the TLR2 agonist Pam3-Cys-SK4(PCSK) significantly increased fluorescent staining of occludin in the TJ. Pretreatment of Caco-2 monolayers with L. plantarum or PCSK significantly attenuated the effects of phorbol ester-induced dislocation of ZO-1 and occludin and the associated increase in epithelial permeability. Our results identifying commensal bacterial stimulation of TLR2 in the gut epithelium as a regulator of epithelial integrity have important implications for understanding probiotic mechanisms and the control of intestinal homeostasis.

scholarly journals HIF-dependent regulation of claudin-1 is central to intestinal epithelial tight junction integrity

2015 ◽  
Vol 26 (12) ◽  
pp. 2252-2262 ◽  
Author(s):  
Bejan J. Saeedi ◽  
Daniel J. Kao ◽  
David A. Kitzenberg ◽  
Evgenia Dobrinskikh ◽  
Kayla D. Schwisow ◽  
...  
Keyword(s):  
Tight Junction ◽  
Barrier Function ◽  
Experimental Colitis ◽  
Site Directed Mutagenesis ◽  
Intestinal Epithelial ◽  
Low Oxygen ◽  
T84 Cells ◽  
Transcriptional Responses ◽  
Epithelial Tight Junction

Intestinal epithelial cells (IECs) are exposed to profound fluctuations in oxygen tension and have evolved adaptive transcriptional responses to a low-oxygen environment. These adaptations are mediated primarily through the hypoxia-inducible factor (HIF) complex. Given the central role of the IEC in barrier function, we sought to determine whether HIF influenced epithelial tight junction (TJ) structure and function. Initial studies revealed that short hairpin RNA–mediated depletion of the HIF1β in T84 cells resulted in profound defects in barrier and nonuniform, undulating TJ morphology. Global HIF1α chromatin immunoprecipitation (ChIP) analysis identified claudin-1 (CLDN1) as a prominent HIF target gene. Analysis of HIF1β-deficient IEC revealed significantly reduced levels of CLDN1. Overexpression of CLDN1 in HIF1β-deficient cells resulted in resolution of morphological abnormalities and restoration of barrier function. ChIP and site-directed mutagenesis revealed prominent hypoxia response elements in the CLDN1 promoter region. Subsequent in vivo analysis revealed the importance of HIF-mediated CLDN1 expression during experimental colitis. These results identify a critical link between HIF and specific tight junction function, providing important insight into mechanisms of HIF-regulated epithelial homeostasis.

scholarly journals Intestinal epithelial barrier function and tight junction proteins with heat and exercise

2016 ◽  
Vol 120 (6) ◽  
pp. 692-701 ◽  
Author(s):  
Karol Dokladny ◽  
Micah N. Zuhl ◽  
Pope L. Moseley
Keyword(s):  
Heat Stress ◽  
Tight Junction ◽  
Barrier Function ◽  
Epithelial Barrier ◽  
Intestinal Epithelial ◽  
Tight Junction Proteins ◽  
Intestinal Epithelial Barrier ◽  
Epithelial Tight Junction ◽  
Junction Proteins

A single layer of enterocytes and tight junctions (intercellular multiprotein complexes) form the intestinal epithelial barrier that controls transport of molecules through transcellular and paracellular pathways. A dysfunctional or “leaky” intestinal tight junction barrier allows augmented permeation of luminal antigens, endotoxins, and bacteria into the blood stream. Various substances and conditions have been shown to affect the maintenance of the intestinal epithelial tight junction barrier. The primary focus of the present review is to analyze the effects of exertional or nonexertional (passive hyperthermia) heat stress on tight junction barrier function in in vitro and in vivo (animals and humans) models. Our secondary focus is to review changes in tight junction proteins in response to exercise or hyperthermic conditions. Finally, we discuss some pharmacological or nutritional interventions that may affect the cellular mechanisms involved in maintaining homeostasis of the intestinal epithelial tight junction barrier during heat stress or exercise.

scholarly journals MMP-9-induced increase in intestinal epithelial tight permeability is mediated by p38 kinase signaling pathway activation of MLCK gene

2019 ◽  
Vol 316 (2) ◽  
pp. G278-G290 ◽  
Author(s):  
Rana Al-Sadi ◽  
Moustafa Youssef ◽  
Manmeet Rawat ◽  
Shuhong Guo ◽  
Karol Dokladny ◽  
...  
Keyword(s):  
Protein Expression ◽  
Intestinal Permeability ◽  
Barrier Function ◽  
Intestinal Inflammation ◽  
Gene Activity ◽  
Intestinal Epithelial ◽  
P38 Kinase ◽  
Kinase Signaling Pathway

Matrix metalloproteinase-9 (MMP-9) has been implicated as being an important pathogenic factor in inflammatory bowel disease (IBD). MMP-9 is markedly elevated in intestinal tissue of patients with IBD, and IBD patients have a defective intestinal tight-junction (TJ) barrier manifested by an increase in intestinal permeability. The loss of intestinal epithelial barrier function is an important contributing factor in the development and prolongation of intestinal inflammation; however, the role of MMP-9 in intestinal barrier function remains unclear. The purpose of this study was to investigate the effect of MMP-9 on the intestinal epithelial TJ barrier and to delineate the intracellular mechanisms involved by using in vitro (filter-grown Caco-2 monolayers) and in vivo (mouse small intestine recycling perfusion) systems. MMP-9 caused a time- and dose-dependent increase in Caco-2 TJ permeability. MMP-9 also caused an increase in myosin light-chain kinase (MLCK) gene activity, protein expression, and enzymatic activity. The pharmacological MLCK inhibition and siRNA-induced knockdown of MLCK inhibited the MMP-9-induced increase in Caco-2 TJ permeability. MMP-9 caused a rapid activation of the p38 kinase signaling pathway and inhibition of p38 kinase activity prevented the MMP-9-induced increase in MLCK gene activity and the increase in Caco-2 TJ permeability. MMP-9 also caused an increase in mouse intestinal permeability in vivo, which was accompanied by an increase in MLCK expression. The MMP-9-induced increase in mouse intestinal permeability was inhibited in MLCK-deficient mice. These data show for the first time that the MMP-9-induced increase in intestinal TJ permeability in vitro and in vivo was mediated by the p38 kinase signal transduction pathway upregulation of MLCK gene activity and that therapeutic targeting of these pathways can prevent the MMP-9-induced increase in intestinal TJ permeability. NEW & NOTEWORTHY MMP-9 is highly elevated in patients with IBD. IBD patients have compromised intestinal TJ barrier function manifested by an increase in intestinal permeability and intestinal inflammation. This study shows that MMP-9, at clinically achievable concentrations, causes an increase in intestinal TJ permeability in vitro and in vivo. In addition, a MMP-9-induced increase in intestinal TJ permeability was mediated by an increase in MLCK gene and protein expression via the p38 kinase pathway.

scholarly journals Exploring Effects of Chitosan Oligosaccharides on the DSS-Induced Intestinal Barrier Impairment In Vitro and In Vivo

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2199
Author(s):  
Yujie Wang ◽  
Rong Wen ◽  
Dongdong Liu ◽  
Chen Zhang ◽  
Zhuo A. Wang ◽  
...  
Keyword(s):  
Tight Junction ◽  
Structural Characteristics ◽  
Intestinal Barrier ◽  
Intestinal Barrier Function ◽  
Chitosan Oligosaccharide ◽  
Intestinal Epithelial ◽  
Mucus Layer ◽  
Intestinal Mucus ◽  
Epithelial Tight Junction

Intestinal barrier dysfunction is an essential pathological change in inflammatory bowel disease (IBD). The mucus layer and the intestinal epithelial tight junction act together to maintain barrier integrity. Studies showed that chitosan oligosaccharide (COS) had a positive effect on gut health, effectively protecting the intestinal barrier in IBD. However, these studies usually focused on its impact on the intestinal epithelial tight junction. The influence of COS on the intestinal mucus layer is still poorly understood. In this study, we explored the effect of COS on intestinal mucus in vitro using human colonic mucus-secreted HT-29 cells. COS relieved DSS (dextran sulfate sodium)-induced mucus defects. Additionally, the structural characteristics of COS greatly influenced this activity. Finally, we evaluated the protective effect of COS on intestinal barrier function in mice with DSS-induced colitis. The results indicated that COS could manipulate intestinal mucus production, which likely contributed to its intestinal protective effects.

Tu1348 Mechanism of IL-1β Effect on Mouse Intestinal Epithelial Tight Junction Permeability In-Vivo

2012 ◽  
Vol 142 (5) ◽  
pp. S-808
Author(s):  
Rana Al-Sadi ◽  
Shuhong Guo ◽  
Karol Dokladny ◽  
Archana Kaza ◽  
Thomas Y. Ma
Keyword(s):  
Tight Junction ◽  
Intestinal Epithelial ◽  
Epithelial Tight Junction ◽  
Tight Junction Permeability
Sign in / Sign up

Export Citation Format

Share Document