Physiologically relevant increase in temperature causes an increase in intestinal epithelial tight junction permeability

2006 ◽  
Vol 290 (2) ◽  
pp. G204-G212 ◽  
Author(s):  
Karol Dokladny ◽  
Pope L. Moseley ◽  
Thomas Y. Ma
Keyword(s):  
Heat Stress ◽  
Protein Expression ◽  
Tight Junction ◽  
Heat Exposure ◽  
Protective Role ◽  
Intestinal Epithelial ◽  
Epithelial Tight Junction ◽  
Shock Proteins

The effects of physiologically relevant increase in temperature (37–41°C) on intestinal epithelial tight junction (TJ) barrier have not been previously studied. Additionally, the role of heat-shock proteins (HSPs) in the regulation of intestinal TJ barrier during heat stress remains unknown. Because heat-induced disturbance of intestinal TJ barrier could lead to endotoxemia and bacterial translocation during physiological thermal stress, the purpose of this study was to investigate the effects of modest, physiologically relevant increases in temperature (37–41°C) on intestinal epithelial TJ barrier and to examine the protective role of HSPs on intestinal TJ barrier. Filter-grown Caco-2 intestinal epithelial cells were used as an in vitro intestinal epithelial model system to assess the effects of heat exposure on intestinal TJ barrier. Exposure of filter-grown Caco-2 monolayers to modest increases in temperatures (37–41°C) resulted in a significant time- and temperature-dependent increases in Caco-2 TJ permeability. Exposure to modest heat (39 or 41°C) resulted in rapid and sustained increases in HSP expression; and inhibition of HSP expression produced a marked increase in heat-induced increase in Caco-2 TJ permeability ( P < 0.001). Heat exposure (41°C) resulted in a compensatory increase in Caco-2 occludin protein expression and an increase in junctional localization. Inhibition of HSP expression prevented the compensatory upregulation of occludin protein expression and produced a marked disruption in junctional localization of occludin protein during heat stress. In conclusion, our findings demonstrate for the first time that a modest, physiologically relevant increase in temperature causes an increase in intestinal epithelial TJ permeability. Our data also show that HSPs play an important protective role in preventing the heat-induced disruption of intestinal TJ barrier and suggest that HSP mediated upregulation of occludin expression may be an important mechanism involved in the maintenance of intestinal epithelial TJ barrier function during heat stress.

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.

TNF-α-induced increase in intestinal epithelial tight junction permeability requires NF-κB activation

2004 ◽  
Vol 286 (3) ◽  
pp. G367-G376 ◽  
Author(s):  
Thomas Y. Ma ◽  
Gary K. Iwamoto ◽  
Neil T. Hoa ◽  
Vimesh Akotia ◽  
Ali Pedram ◽  
...  
Keyword(s):  
Protein Expression ◽  
Tight Junction ◽  
Etiologic Factor ◽  
Intestinal Epithelial ◽  
Tnf Α ◽  
Abnormal Increase ◽  
Epithelial Tight Junction ◽  
Tight Junction Permeability ◽  
First Time

Crohn's disease (CD) patients have an abnormal increase in intestinal epithelial permeability. The defect in intestinal tight junction (TJ) barrier has been proposed as an important etiologic factor of CD. TNF-α increases intestinal TJ permeability. Because TNF-α levels are markedly increased in CD, TNF-α increase in intestinal TJ permeability could be a contributing factor of intestinal permeability defect in CD. Our purpose was to determine some of the intracellular mechanisms involved in TNF-α modulation of intestinal epithelial TJ permeability by using an in vitro intestinal epithelial system consisting of filter-grown Caco-2 monolayers. TNF-α produced a concentration- and time-dependent increase in Caco-2 TJ permeability. TNF-α-induced increase in Caco-2 TJ permeability correlated with Caco-2 NF-κB activation. Inhibition of TNF-α-induced NF-κB activation by selected NF-κB inhibitors, curcumin and triptolide, prevented the increase in Caco-2 TJ permeability, indicating that NF-κB activation was required for the TNF-α-induced increase in Caco-2 TJ permeability. This increase in Caco-2 TJ permeability was accompanied by down-regulation of zonula occludens (ZO)-1 proteins and alteration in junctional localization of ZO-1 proteins. TNF-α modulation of ZO-1 protein expression and junctional localization were also prevented by NF-κB inhibitors. TNF-α did not induce apoptosis in Caco-2 cells, suggesting that apoptosis was not the mechanism involved in TNF-α-induced increase in Caco-2 TJ permeability. These results demonstrate for the first time that TNF-α-induced increase in Caco-2 TJ permeability was mediated by NF-κB activation. The increase in permeability was associated with NF-κB-dependent downregulation of ZO-1 protein expression and alteration in junctional localization.

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

Mechanism of TNF-α modulation of Caco-2 intestinal epithelial tight junction barrier: role of myosin light-chain kinase protein expression

2005 ◽  
Vol 288 (3) ◽  
pp. G422-G430 ◽  
Author(s):  
Thomas Y. Ma ◽  
Michel A. Boivin ◽  
Dongmei Ye ◽  
Ali Pedram ◽  
Hamid M. Said
Keyword(s):  
Protein Expression ◽  
Tight Junction ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Intestinal Inflammation ◽  
Intestinal Epithelial ◽  
Mrna Transcription ◽  
Tnf Α ◽  
Epithelial Tight Junction

TNF-α plays a central role in the intestinal inflammation of various inflammatory disorders including Crohn's disease (CD). TNF-α-induced increase in intestinal epithelial tight junction (TJ) permeability has been proposed as one of the proinflammatory mechanisms contributing to the intestinal inflammation. The intracellular mechanisms involved in the TNF-α-induced increase in intestinal TJ permeability remain unclear. The purpose of this study was to investigate the possibility that the TNF-α-induced increase in intestinal epithelial TJ permeability was regulated by myosin light-chain kinase (MLCK) protein expression, using an in vitro intestinal epithelial model system consisting of the filter-grown Caco-2 intestinal epithelial monolayers. TNF-α (10 ng/ml) produced a time-dependent increase in Caco-2 MLCK expression. The TNF-α increase in MLCK protein expression paralleled the increase in Caco-2 TJ permeability, and the inhibition of the TNF-α-induced MLCK expression (by cycloheximide) prevented the increase in Caco-2 TJ permeability, suggesting that MLCK expression may be required for the increase in Caco-2 TJ permeability. The TNF-α increase in MLCK protein expression was preceded by an increase in MLCK mRNA expression but not an alteration in MLCK protein degradation. Actinomycin-D prevented the TNF-α increase in MLCK mRNA expression and the subsequent increase in MLCK protein expression and Caco-2 TJ permeability, suggesting that the increase in MLCK mRNA transcription led to the increase in MLCK expression. The TNF-α increase in MLCK protein expression was also associated with an increase in Caco-2 MLCK activity. The cycloheximide inhibition of MLCK protein expression prevented the TNF-α increase in MLCK activity and Caco-2 TJ permeability. Moreover, inhibitors of MLCK, Mg2+-myosin ATPase, and metabolic energy prevented the TNF-α increase in Caco-2 TJ permeability, suggesting that the increase in MLCK activity was required for the TNF-α-induced opening of the Caco-2 TJ barrier. In conclusion, our results indicate for the first time that 1) the TNF-α increase in Caco-2 TJ permeability was mediated by an increase in MLCK protein expression, 2) the increase in MLCK protein expression was regulated by an increase in MLCK mRNA transcription, and 3) the increase in Caco-2 TJ permeability required MLCK protein expression-dependent increase in MLCK activity.

scholarly journals CCAAT/Enhancer-Binding Protein Homologous Protein (CHOP) Deficiency Attenuates Heatstroke-Induced Intestinal Injury

Inflammation ◽  
2021 ◽  
Author(s):  
Yan Cao ◽  
Maiying Fan ◽  
Yanfang Pei ◽  
Lei Su ◽  
Weiwei Xiao ◽  
...  
Keyword(s):  
Protein Expression ◽  
Er Stress ◽  
Intestinal Barrier ◽  
Intestinal Injury ◽  
Intestinal Epithelial ◽  
Barrier Dysfunction ◽  
Homologous Protein

Abstract The intestine is one of the main target organs involved in the pathological process of heatstroke. CCAAT/enhancer-binding protein homologous protein (CHOP) is involved in endoplasmic reticulum (ER) stress-induced apoptosis. This study aimed to explore the role of CHOP in heatstroke-induced intestinal injury and potential therapy. An in vitro heat stress (HS) model using Caco-2 cells was employed. We observed the role of CHOP in apoptosis-mediated intestinal epithelial cell injury secondary to HS by evaluating cell viability, lactate dehydrogenase release, apoptosis levels, and GRP78, PERK, ATF4, CHOP, Bcl-2, and BAX mRNA and protein expression. To further study the role of CHOP in HS-induced intestinal barrier dysfunction, we assessed transepithelial electrical resistance, paracellular tracer flux, ultrastructure of tight junctions, and protein expression of ZO-1 and occludin. Male wild-type mice and CHOP knockout mice were used for in vivo experiments. We evaluated serum d-lactate and diamine oxidase levels, histopathological changes, intestinal ultrastructure, and ZO-1 and occludin protein expression. HS activated the PERK-CHOP pathway and promoted apoptosis by upregulating BAX and downregulating Bcl-2; these effects were prevented by CHOP silencing. Intestinal epithelial barrier function was disrupted by HS in vitro and in vivo. CHOP silencing prevented intestinal barrier dysfunction in Caco-2 cells, whereas CHOP knockout mice exhibited decreased intestinal mucosal injury. The ER stress inhibitor 4-phenylbutyrate (4-PBA) prevented HS-induced intestinal injury in vitro and in vivo. This study indicated that CHOP deficiency attenuates heatstroke-induced intestinal injury and may contribute to the identification of a novel therapy against heatstroke associated with the ER stress pathway.

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 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.

Molecular mechanism of tumor necrosis factor-α modulation of intestinal epithelial tight junction barrier

2006 ◽  
Vol 290 (3) ◽  
pp. G496-G504 ◽  
Author(s):  
Dongmei Ye ◽  
Iris Ma ◽  
Thomas Y. Ma
Keyword(s):  
Protein Expression ◽  
Tight Junction ◽  
Binding Site ◽  
Promoter Region ◽  
Promoter Activity ◽  
Molecular Mechanisms ◽  
Intestinal Inflammation ◽  
Intestinal Epithelial ◽  
Tnf Α ◽  
Epithelial Tight Junction

A TNF-α-induced increase in intestinal epithelial tight junction (TJ) permeability has been proposed to be an important proinflammatory mechanism contributing to intestinal inflammation in Crohn's disease and other inflammatory conditions. Previous studies from our laboratory suggested that the TNF-α-induced increase in intestinal TJ permeability was mediated by an increase in myosin light chain kinase (MLCK) protein expression. However, the molecular mechanisms that mediate the TNF-α increase in intestinal TJ permeability and MLCK protein expression remain unknown. The purpose of this study was to delineate the intracellular and molecular mechanisms that mediate the TNF-α-induced increase in intestinal TJ permeability; using an in vitro intestinal epithelial model system consisting of filter-grown Caco-2 intestinal epithelial monolayers. To examine the molecular mechanisms involved in the TNF-α regulation of intestinal TJ barrier, we identified and cloned for the first time a functionally active MLCK promoter region. TNF-α treatment of filter-grown Caco-2 monolayers transfected with plasmid vector containing the MLCK promoter region produced an increase in MLCK promoter activity and MLCK transcription. The TNF-α-induced increase in MLCK transcription corresponded to a sequential increase in MLCK protein expression, MLCK activity, and Caco-2 TJ permeability. The TNF-α-induced increase in MLCK promoter activity was mediated by NF-κB activation, and the inhibition of NF-κB activation prevented the TNF-α-induced increase in promoter activity and the subsequent increase in MLCK protein expression and Caco-2 TJ permeability. The TNF-α-induced activation of MLCK promoter was mediated by binding of the activated NF-κB p50/p65 dimer to the downstream κB binding site (−84 to −75) on the MLCK promoter region; deletion of the κB binding site prevented the TNF-α increase in promoter activity. Additionally, siRNA silencing of NF-κB p65 also prevented the TNF-α increase in MLCK promoter activity. In conclusion, our findings indicated that the TNF-α-induced increase in intestinal epithelial TJ permeability was mediated by NF-κB p50/p65 binding and activation of the MLCK promoter. NF-κB p50/p65 activation of the MLCK promoter then leads to a stepwise increase in MLCK transcription, expression and activity, and MLCK-mediated opening of the intestinal TJ barrier.

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