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 The In Vitro Protective Role of Bovine Lactoferrin on Intestinal Epithelial Barrier

Molecules ◽  
2019 ◽  
Vol 24 (1) ◽  
pp. 148 ◽  
Author(s):  
Xiao Zhao ◽  
Xiao-Xi Xu ◽  
Yang Liu ◽  
En-Ze Xi ◽  
Jing-Jing An ◽  
...  
Keyword(s):  
Tight Junction ◽  
Barrier Function ◽  
Growth Promotion ◽  
Protective Role ◽  
Intestinal Barrier Function ◽  
Epithelial Barrier ◽  
Bovine Lactoferrin ◽  
Intestinal Epithelial ◽  
Intestinal Epithelial Barrier

The intestinal epithelial barrier plays a key protective role in the gut lumen. Bovine lactoferrin (bLF) has been reported to improve the intestinal epithelial barrier function, but its impact on tight junction (TJ) proteins has been rarely described. Human intestinal epithelial crypt cells (HIECs) were more similar to those in the human small intestine, compared with the well-established Caco-2 cells. Accordingly, both HIECs and Caco-2 cells were investigated in this study to determine the effects of bioactive protein bLF on their growth promotion and intestinal barrier function. The results showed that bLF promoted cell growth and arrested cell-cycle progression at the G2/M-phase. Moreover, bLF decreased paracellular permeability and increased alkaline phosphatase activity and transepithelial electrical resistance, strengthening barrier function. Immunofluorescence, western blot and quantitative real-time polymerase chain reaction revealed that bLF significantly increased the expression of three tight junction proteins—claudin-1, occludin, and ZO-1—at both the mRNA and protein levels, and consequently strengthened the barrier function of the two cell models. bLF in general showed higher activity in Caco-2 cells, however, HIECs also exhibited desired responses to barrier function. Therefore, bLF may be incorporated into functional foods for treatment of inflammatory bowel diseases which are caused by loss of barrier integrity.

scholarly journals Lactobacillus plantarum inhibits intestinal epithelial barrier dysfunction induced by unconjugated bilirubin

2010 ◽  
Vol 104 (3) ◽  
pp. 390-401 ◽  
Author(s):  
Yukun Zhou ◽  
Huanlong Qin ◽  
Ming Zhang ◽  
Tongyi Shen ◽  
Hongqi Chen ◽  
...  
Keyword(s):  
Tight Junction ◽  
Lactobacillus Plantarum ◽  
Laser Scanning Microscopy ◽  
Unconjugated Bilirubin ◽  
Epithelial Barrier ◽  
Intestinal Epithelial ◽  
Tight Junction Proteins ◽  
Intestinal Epithelial Barrier ◽  
Junction Protein ◽  
Junction Proteins

Although a large number of in vitro and in vivo tests have confirmed that taking probiotics can improve the intestinal barrier, few studies have focused on the relationship between probiotics and the intestinal epithelial barrier in hyperbilirubinaemia. To investigate the effects of and mechanisms associated with probiotic bacteria (Lactobacillus plantarum; LP) and unconjugated bilirubin (UCB) on the intestinal epithelial barrier, we measured the viability, apoptotic ratio and protein kinase C (PKC) activity of Caco-2 cells. We also determined the distribution and expression of tight junction proteins such as occludin, zonula occludens (ZO)-1, claudin-1, claudin-4, junctional adhesion molecule (JAM)-1 and F-actin using confocal laser scanning microscopy, immunohistochemistry, Western blotting and real-time quantitative PCR. The present study demonstrated that high concentrations of UCB caused obvious cytotoxicity and decreased the transepithelial electrical resistance (TER) of the Caco-2 cell monolayer. Low concentrations of UCB inhibited the expression of tight junction proteins and PKC but could induce UDP-glucuronosyltransferases 1 family-polypeptide A1 (UGT1A1) expression. UCB alone caused decreased PKC activity, serine phosphorylated occludin and ZO-1 levels. After treatment with LP, the effects of UCB on TER and apoptosis were mitigated; LP also prevented aberrant expression and rearrangement of tight junction proteins. Moreover, PKC activity and serine phosphorylated tight junction protein levels were partially restored after treatment with LP, LP exerted a protective effect against UCB damage to Caco-2 monolayer cells, and it restored the structure and distribution of tight junction proteins by activating the PKC pathway. In addition, UGT1A1 expression induced by UCB in Caco-2 cells could ameliorate the cytotoxicity of UCB.

Polyamines are necessary for synthesis and stability of occludin protein in intestinal epithelial cells

2005 ◽  
Vol 288 (6) ◽  
pp. G1159-G1169 ◽  
Author(s):  
Xin Guo ◽  
Jaladanki N. Rao ◽  
Lan Liu ◽  
Tongtong Zou ◽  
Kaspar M. Keledjian ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Tight Junction ◽  
Barrier Function ◽  
Intestinal Epithelial Cells ◽  
Integral Membrane Protein ◽  
Epithelial Barrier ◽  
Intestinal Epithelial ◽  
Tight Junction Proteins ◽  
Epithelial Barrier Function ◽  
Junction Proteins

Occludin is an integral membrane protein that forms the sealing element of tight junctions and is critical for epithelial barrier function. Polyamines are implicated in multiple signaling pathways driving different biological functions of intestinal epithelial cells (IEC). The present study determined whether polyamines are involved in expression of occludin and play a role in intestinal epithelial barrier function. Studies were conducted in stable Cdx2-transfected IEC-6 cells (IEC-Cdx2L1) associated with a highly differentiated phenotype. Polyamine depletion by α-difluoromethylornithine (DFMO) decreased levels of occludin protein but failed to affect expression of its mRNA. Other tight junction proteins, zonula occludens (ZO)-1, ZO-2, claudin-2, and claudin-3, were also decreased in polyamine-deficient cells. Decreased levels of tight junction proteins in DFMO-treated cells were associated with dysfunction of the epithelial barrier, which was overcome by exogenous polyamine spermidine. Decreased levels of occludin in polyamine-deficient cells was not due to the reduction of intracellular-free Ca2+ concentration ([Ca2+]cyt), because either increased or decreased [Ca2+]cyt did not alter levels of occludin in the presence or absence of polyamines. The level of newly synthesized occludin protein was decreased by ∼70% following polyamine depletion, whereas its protein half-life was reduced from ∼120 min in control cells to ∼75 min in polyamine-deficient cells. These findings indicate that polyamines are necessary for the synthesis and stability of occludin protein and that polyamine depletion disrupts the epithelial barrier function, at least partially, by decreasing occludin.

scholarly journals JunD Represses Transcription and Translation of the Tight Junction Protein Zona Occludens-1 Modulating Intestinal Epithelial Barrier Function

2008 ◽  
Vol 19 (9) ◽  
pp. 3701-3712 ◽  
Author(s):  
Jie Chen ◽  
Lan Xiao ◽  
Jaladanki N. Rao ◽  
Tongtong Zou ◽  
Lan Liu ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Tight Junction ◽  
Barrier Function ◽  
Intestinal Epithelial Cells ◽  
Binding Protein ◽  
Mrna Translation ◽  
Epithelial Barrier ◽  
Intestinal Epithelial ◽  
Intestinal Epithelial Barrier ◽  
Epithelial Barrier Function

The AP-1 transcription factor JunD is highly expressed in intestinal epithelial cells, but its exact role in maintaining the integrity of intestinal epithelial barrier remains unknown. The tight junction (TJ) protein zonula occludens (ZO)-1 links the intracellular domain of TJ-transmembrane proteins occludin, claudins, and junctional adhesion molecules to many cytoplasmic proteins and the actin cytoskeleton and is crucial for assembly of the TJ complex. Here, we show that JunD negatively regulates expression of ZO-1 and is implicated in the regulation of intestinal epithelial barrier function. Increased JunD levels by ectopic overexpression of the junD gene or by depleting cellular polyamines repressed ZO-1 expression and increased epithelial paracellular permeability. JunD regulated ZO-1 expression at the levels of transcription and translation. Transcriptional repression of ZO-1 by JunD was mediated through cAMP response element-binding protein-binding site within its proximal region of the ZO-1-promoter, whereas induced JunD inhibited ZO-1 mRNA translation by enhancing the interaction of the ZO-1 3′-untranslated region with RNA-binding protein T cell-restricted intracellular antigen 1-related protein. These results indicate that JunD is a biological suppressor of ZO-1 expression in intestinal epithelial cells and plays a critical role in maintaining epithelial barrier function.

Digestion of epithelial tight junction proteins by the commensal Clostridium perfringens

2013 ◽  
Vol 305 (10) ◽  
pp. G740-G748 ◽  
Author(s):  
Mihaela Pruteanu ◽  
Fergus Shanahan
Keyword(s):  
Epithelial Cell ◽  
Tight Junction ◽  
Clostridium Perfringens ◽  
Culture Supernatant ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
Tight Junction Proteins ◽  
Epithelial Tight Junction ◽  
Junction Proteins ◽  
E Cadherin

The enteric microbiota contributes to the pathogenesis of inflammatory bowel disease, but the pathways involved and bacterial participants may vary in different hosts. We previously reported that some components of the human commensal microbiota, particularly Clostridium perfringens ( C. perfringens), have the proteolytic capacity for host matrix degradation and reduce transepithelial resistance. Here, we examined the C. perfringens-derived proteolytic activity against epithelial tight junction proteins using human intestinal epithelial cell lines. We showed that the protein levels of E-cadherin, occludin, and junctional adhesion molecule 1 decrease in colonic cells treated with C. perfringens culture supernatant. E-cadherin ectodomain shedding in C. perfringens-stimulated intestinal epithelial cells was detected with antibodies against the extracellular domain of E-cadherin, and we demonstrate that this process occurs in a time- and dose-dependent manner. In addition, we showed that the filtered sterile culture supernatant of C. perfringens has no cytotoxic activity on the human intestinal cells at the concentrations used in this study. The direct cleavage of E-cadherin by the proteases from the C. perfringens culture supernatant was confirmed by C. perfringens supernatant-induced in vitro degradation of the human recombinant E-cadherin. We conclude that C. perfringens culture supernatant mediates digestion of epithelial cell junctional proteins, which is likely to enable access to the extracellular matrix components by the paracellular pathway.

scholarly journals Chymase-mediated intestinal epithelial permeability is regulated by a protease-activating receptor/matrix metalloproteinase-2-dependent mechanism

2013 ◽  
Vol 304 (5) ◽  
pp. G479-G489 ◽  
Author(s):  
Katherine R. Groschwitz ◽  
David Wu ◽  
Heather Osterfeld ◽  
Richard Ahrens ◽  
Simon P. Hogan
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Barrier Function ◽  
Epithelial Barrier ◽  
Intestinal Epithelial ◽  
Barrier Dysfunction ◽  
Intestinal Epithelial Barrier ◽  
Epithelial Barrier Function ◽  
Epithelial Barrier Dysfunction

Mast cells regulate intestinal barrier function during disease and homeostasis. Secretion of the mast cell-specific serine protease chymase regulates homeostasis. In the present study, we employ in vitro model systems to delineate the molecular pathways involved in chymase-mediated intestinal epithelial barrier dysfunction. Chymase stimulation of intestinal epithelial (Caco-2 BBe) cell monolayers induced a significant reduction in transepithelial resistance, indicating decreased intestinal epithelial barrier function. The chymase-induced intestinal epithelial barrier dysfunction was characterized by chymase-induced protease-activated receptor (PAR)-2 activation and matrix metalloproteinase (MMP)-2 expression and activation. Consistent with this observation, in vitro analysis revealed chymase-induced PAR-2 activation and increased MAPK activity and MMP-2 expression. Pharmacological and small interfering RNA-mediated antagonism of PAR-2 and MMP-2 significantly attenuated chymase-stimulated barrier dysfunction. Additionally, the chymase/MMP-2-mediated intestinal epithelial dysfunction was associated with a significant reduction in the tight junction protein claudin-5, which was partially restored by MMP-2 inhibition. Finally, incubation of Caco-2 BBe cells with chymase-sufficient, but not chymase-deficient, bone marrow-derived mast cells decreased barrier function, which was attenuated by the chymase inhibitor chymostatin. Collectively, these results suggest that mast cell/chymase-mediated intestinal epithelial barrier function is mediated by PAR-2/MMP-2-dependent pathways.

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