scholarly journals Use of aspirin to intentionally induce gastrointestinal tract barrier dysfunction in feedlot cattle

2020 ◽  
Vol 98 (9) ◽  
Author(s):  
Nathan G Briggs ◽  
Kristen M Brennan ◽  
Bethany J Funnell ◽  
Griffin T Nicholls ◽  
Jon P Schoonmaker
Keyword(s):  
Gastrointestinal Tract ◽  
Beef Cattle ◽  
Tight Junction ◽  
Mrna Expression ◽  
Barrier Function ◽  
Animal Health ◽  
Feedlot Cattle ◽  
Barrier Dysfunction ◽  
Aspirin Dose ◽  
Amyloid A

Abstract Stress negatively affects the gastrointestinal tract (GIT) barrier function, resulting in compromised animal health. A deeper understanding of how diet and stress impacts the GIT barrier function in feedlot cattle is needed. Aspirin decreases mucus production and mucosal repair in the GIT and could be used as a model for GIT barrier dysfunction research. The objective of this study was to evaluate the effectiveness of aspirin to induce GIT barrier dysfunction in beef cattle. In experiment 1, sixteen crossbred heifers (425.0 ± 8.6 kg) were allotted to 0, 50, 100, or 200 mg/kg body weight (BW) aspirin doses based on BW. Experiment 1 consisted of two periods separated by 4 wk where four heifers per treatment received the same aspirin dose during each period. Heifers were fed a 49.4% corn silage and 50.6% concentrate diet. The 200 mg/kg BW aspirin treatment was dosed as a 100 mg/kg BW aspirin oral bolus 36 and 24 h prior to Cr-ethylenediaminetetraacetic acid (EDTA) dosing (1 liter; 180 mM). The 50 and 100 mg/kg BW aspirin treatments were dosed as an oral bolus 24 h prior to Cr-EDTA dosing. Urine was collected every 3 h for 48 h and analyzed for Cr. Serum was collected at 0 and 48 h and analyzed for lipopolysaccharide-binding protein (LBP), interleukin-6, serum amyloid A (SAA), haptoglobin, and aspartate aminotransferase. In experiment 2, sixteen crossbred steers (576.0 ± 14.2 kg) fed a similar diet were allotted by BW to the 0 and 200 mg/kg BW aspirin treatments (eight steers/treatment) and were slaughtered 24 h after the last dose. Jejunal tissues were collected, and claudin (CLDN) 1, 2, and 3, occludin, and zonula occludens tight junction messenger ribonucleic acid (mRNA) expression was determined. Data were analyzed using the MIXED procedure of SAS. Urinary Cr excretion increased linearly at hours 3, 6, 9, and 12 (P ≤ 0.04) as aspirin dose increased from 0 to 200 mg/kg. Aspirin linearly increased Cr absorption (P = 0.02) and elimination (P = 0.04) rates and linearly decreased mean retention time of Cr (P = 0.02). Aspirin increased SAA (P = 0.04) and tended to increase LBP (P = 0.09) in serum but did not affect any other serum inflammatory marker (P ≥ 0.19). Aspirin tended to increase jejunal CLDN-1 mRNA expression (P = 0.10) but did not affect the mRNA expression of other genes regulating tight junction function (P ≥ 0.20). Results from this study indicate that aspirin disrupts the GIT barrier function in beef cattle and has a potential as a model in GIT permeability research.

scholarly journals 72 Use of aspirin to intentionally induce gastrointestinal tract barrier dysfunction in feedlot cattle

2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 44-45
Author(s):  
Nathan G Briggs ◽  
Kristen M Brennan ◽  
Griffin Nicholls ◽  
Jon P Schoonmaker
Keyword(s):  
Gastrointestinal Tract ◽  
Beef Cattle ◽  
Tight Junction ◽  
Mrna Expression ◽  
Barrier Function ◽  
Animal Health ◽  
Absorption Spectrometry ◽  
Feedlot Cattle ◽  
Corn Silage ◽  
Barrier Dysfunction

Abstract Stress negatively effects gastrointestinal tract (GIT) barrier function, resulting in compromised animal health. The objective of this study was to evaluate the effectiveness of aspirin to intentionally induce GIT barrier dysfunction in beef cattle. In experiment 1, sixteen crossbred heifers (425 ± 8.6 kg) were enrolled in 2 experimental periods and allotted by BW to 0, 50, 100, or 200 mg/kg BW aspirin. Four heifers per treatment received the same aspirin dose during each period, which were separated by 4 wks. Heifers were fed a 49.4% corn silage, 50.6% concentrate diet. Aspirin was delivered to animals as an oral bolus. The 200 aspirin treatment was dosed as 100 mg/kg BW aspirin 36 and 24 h prior to Cr-EDTA dosing (1 L; 180 mM). The 50 and 100 aspirin treatments were dosed 24 h prior to Cr-EDTA dosing. Urine was collected every 3 h for 48 h and analyzed for Cr using atomic absorption spectrometry. Serum was collected at 0, 24, and 48 h and analyzed for lipopolysaccharide binding protein (LBP) and interleukin-6 (IL-6) using ELISA. In experiment 2, sixteen crossbred steers (576 ± 14.2 kg) fed the same diet were allotted by BW to the 0 and 200 mg/kg BW aspirin treatments (8 steers/treatment) and were slaughtered 24 h after the last dose. Jejunal tissues were collected and tight junction mRNA expression was determined. Data were analyzed using the MIXED procedure of SAS. Aspirin linearly increased Cr absorption (P = 0.02) and elimination (P = 0.04) rate and linearly decreased mean retention time of Cr (P = 0.02). Aspirin tended to increase jejunal claudin-1 mRNA expression (P = 0.10) but did not affect serum IL-6 or LBP or expression of other jejunal tight junction mRNA (P ≥ 0.20). This study indicates that aspirin disrupts GIT barrier function in beef cattle and has potential as a model in GIT permeability research.

scholarly journals Cystine reduces tight junction permeability and intestinal inflammation induced by oxidative stress in Caco-2 cells

Amino Acids ◽  
2021 ◽  
Author(s):  
Tatsuya Hasegawa ◽  
Ami Mizugaki ◽  
Yoshiko Inoue ◽  
Hiroyuki Kato ◽  
Hitoshi Murakami
Keyword(s):  
Oxidative Stress ◽  
Tight Junction ◽  
Mrna Expression ◽  
Inflammatory Cytokines ◽  
Inflammatory Responses ◽  
Intestinal Barrier ◽  
Barrier Dysfunction ◽  
Whole Cells ◽  
Intestinal Barrier Dysfunction ◽  
Pro Inflammatory Cytokines

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.

scholarly journals Utility of acute phase proteins as biomarkers of transport stress in ewes and beef cattle

2015 ◽  
Vol 4 (2) ◽  
Author(s):  
Francesco Fazio ◽  
Vincenzo Ferrantelli ◽  
Antonello Cicero ◽  
Stefania Casella ◽  
Giuseppe Piccione
Keyword(s):  
Beef Cattle ◽  
Repeated Measures ◽  
Acute Phase Proteins ◽  
Animal Health ◽  
White Blood Cells ◽  
Amyloid A ◽  
Repeated Measures Analysis ◽  
Before And After ◽  
Rest Time ◽  
Transport Stress

The effect of transport on serum amyloid A (SAA), haptoglobin (Hp), Fibrinogen and white blood cells (WBC) was evaluated in 10 ewes and 10 beef cattle. All animals were transported by road for 6 h over a distance of about 490 km with an average speed of 80 km/h. Blood samples, collected via jugular venepuncture, were obtained before and after transport as well as after 12, 24 and 48 h rest time. One-way repeated measures analysis of variance showed a statistically significant effect of sampling time on SAA, Hp, and WBC in ewes and beef cattle. Based on these results, Hp and SAA levels, together with WBC, may be useful indicators of animal health and welfare and in predicting the risk assessment in meat inspection.

scholarly journals The role of zinc deficiency in alcohol-induced intestinal barrier dysfunction

2010 ◽  
Vol 298 (5) ◽  
pp. G625-G633 ◽  
Author(s):  
Wei Zhong ◽  
Craig J. McClain ◽  
Matthew Cave ◽  
Y. James Kang ◽  
Zhanxiang Zhou
Keyword(s):  
Oxidative Stress ◽  
Tight Junction ◽  
Zinc Deficiency ◽  
Barrier Function ◽  
Intestinal Barrier ◽  
Alcohol Exposure ◽  
Epithelial Barrier ◽  
Tight Junction Proteins ◽  
Barrier Dysfunction ◽  
Junction Proteins

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.

scholarly journals Soy isoflavones improves endometrial barrier through tight junction gene expression

Reproduction ◽  
2015 ◽  
Vol 149 (3) ◽  
pp. 269-280 ◽  
Author(s):  
Pongpat Kiatprasert ◽  
Chatsri Deachapunya ◽  
Chutamas Benjanirat ◽  
Sutthasinee Poonyachoti
Keyword(s):  
Tight Junction ◽  
Mrna Expression ◽  
Barrier Function ◽  
Soy Isoflavones ◽  
Gene Expressions ◽  
Epithelial Barrier Function ◽  
Gene Transcription Level ◽  
Ameliorative Effect ◽  
Zona Occludens ◽  
Endometrial Epithelial Cells

Contamination with bacterial endotoxin causes the disruption of the tight junction (TJ) barrier. We investigated the ameliorative effect of dietary flavonoids genistein (Ge) and daidzein (Di) in normal or lipopolysaccharide (LPS)-induced disruption of epithelial barrier function of the endometrium. Using the immortalized porcine glandular endometrial epithelial cells (PEG), transepithelial electrical resistance (TER) and FITC-dextran flux (FD-4) across the monolayer were measured. The mRNA expression of TJ proteins, zona occludens-1 (ZO1), and claudin-1, -3, -4, -7 and -8 was evaluated by real-time RT-PCR for coinciding effect of Ge or Di occurred at the gene transcription level. The results revealed that Ge and Di altered the TER, depending on times and concentrations. Low concentration (10−10 M) of both compounds decreased the TER, whereas higher concentrations (10−8and 10−6 M) increased the TER which was not related to the FD-4 flux. The increased TER by Ge or Di was parallel to the induction ofclaudin-3and-4or-8mRNA expression respectively. With LPS inoculation, all isoflavone treatments inhibited the decreased TER induced by LPS, but only Ge (10−8or 10−6 M) or Di (10−10or 10−6 M) was coincidence with the decreased FD-4 flux. Under this LPS-stimulated condition, some or all examined TJ gene expressions appeared to be promoted by specific concentration of Ge or Di respectively. Our findings suggest that the soy isoflavones treatment could promote and restore the impaired endometrial barrier function caused by LPS contamination.

scholarly journals Myosin light chain kinase mediates intestinal barrier dysfunction via occludin endocytosis during anoxia/reoxygenation injury

2016 ◽  
Vol 311 (6) ◽  
pp. C996-C1004 ◽  
Author(s):  
Younggeon Jin ◽  
Anthony T. Blikslager
Keyword(s):  
Tight Junction ◽  
Light Chain ◽  
Barrier Function ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Barrier Dysfunction ◽  
Junction Protein ◽  
Mlc Phosphorylation

Intestinal anoxia/reoxygenation (A/R) injury induces loss of barrier function followed by epithelial repair. Myosin light chain kinase (MLCK) has been shown to alter barrier function via regulation of interepithelial tight junctions, but has not been studied in intestinal A/R injury. We hypothesized that A/R injury would disrupt tight junction barrier function via MLCK activation and myosin light chain (MLC) phosphorylation. Caco-2BBe1 monolayers were subjected to anoxia for 2 h followed by reoxygenation in 21% O2, after which barrier function was determined by measuring transepithelial electrical resistance (TER) and FITC-dextran flux. Tight junction proteins and MLCK signaling were assessed by Western blotting, real-time PCR, or immunofluorescence microscopy. The role of MLCK was further investigated with select inhibitors (ML-7 and peptide 18) by using in vitro and ex vivo models. Following A/R injury, there was a significant increase in paracellular permeability compared with control cells, as determined by TER and dextran fluxes ( P < 0.05). The tight junction protein occludin was internalized during A/R injury and relocalized to the region of the tight junction after 4 h of recovery. MLC phosphorylation was significantly increased by A/R injury ( P < 0.05), and treatment with the MLCK inhibitor peptide 18 attenuated the increased epithelial monolayer permeability and occludin endocytosis caused by A/R injury. Application of MLCK inhibitors to ischemia-injured porcine ileal mucosa induced significant increases in TER and reduced mucosal-to-serosal fluxes of3H-labeled mannitol. These data suggest that MLCK-induced occludin endocytosis mediates intestinal epithelial barrier dysfunction during A/R injury. Our results also indicate that MLCK-dependent occludin regulation may be a target for the therapeutic treatment of ischemia/reperfusion injury.

scholarly journals Occludin S408 phosphorylation regulates tight junction protein interactions and barrier function

2011 ◽  
Vol 193 (3) ◽  
pp. 565-582 ◽  
Author(s):  
David R. Raleigh ◽  
Devin M. Boe ◽  
Dan Yu ◽  
Christopher R. Weber ◽  
Amanda M. Marchiando ◽  
...  
Keyword(s):  
Tight Junction ◽  
Dynamic Behavior ◽  
Protein Interactions ◽  
Protein Complex ◽  
Barrier Function ◽  
Therapeutic Potential ◽  
Paracellular Permeability ◽  
Tight Junction Protein ◽  
Barrier Dysfunction ◽  
Junction Protein

Although the C-terminal cytoplasmic tail of the tight junction protein occludin is heavily phosphorylated, the functional impact of most individual sites is undefined. Here, we show that inhibition of CK2-mediated occludin S408 phosphorylation elevates transepithelial resistance by reducing paracellular cation flux. This regulation requires occludin, claudin-1, claudin-2, and ZO-1. S408 dephosphorylation reduces occludin exchange, but increases exchange of ZO-1, claudin-1, and claudin-2, thereby causing the mobile fractions of these proteins to converge. Claudin-4 exchange is not affected. ZO-1 domains that mediate interactions with occludin and claudins are required for increases in claudin-2 exchange, suggesting assembly of a phosphorylation-sensitive protein complex. Consistent with this, binding of claudin-1 and claudin-2, but not claudin-4, to S408A occludin tail is increased relative to S408D. Finally, CK2 inhibition reversed IL-13–induced, claudin-2–dependent barrier loss. Thus, occludin S408 dephosphorylation regulates paracellular permeability by remodeling tight junction protein dynamic behavior and intermolecular interactions between occludin, ZO-1, and select claudins, and may have therapeutic potential in inflammation-associated barrier dysfunction.

scholarly journals Filaggrin and tight junction proteins are crucial for IL-13-mediated esophageal barrier dysfunction

2018 ◽  
Vol 315 (3) ◽  
pp. G341-G350 ◽  
Author(s):  
Liping Wu ◽  
Tadayuki Oshima ◽  
Min Li ◽  
Toshihiko Tomita ◽  
Hirokazu Fukui ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Tight Junction ◽  
Barrier Function ◽  
Epithelial Barrier ◽  
Tight Junction Proteins ◽  
Barrier Dysfunction ◽  
Esophageal Epithelial Cells ◽  
Air Liquid Interface ◽  
Related Proteins ◽  
Junction Proteins

Eosinophilic esophagitis (EoE) is an allergy-mediated disease that is accompanied by IL-13 overexpression and an impaired esophageal barrier. Filaggrin (FLG) and tight junction (TJ) proteins are considered to contribute to epithelial barrier function. However, their functional involvement in EoE has not been elucidated. Here, we aimed to determine the IL-13-mediated barrier dysfunction and expression of TJ-related proteins in EoE and to characterize interactions among TJ-related proteins involved in the barrier function of the esophageal epithelium. Biopsy specimens from EoE patients were analyzed. Primary human esophageal epithelial cells (HEECs) were cultured using an air-liquid interface (ALI) system. The permeability of TJs was assayed by biotinylation. Transepithelial electrical resistance (TEER) was measured after stimulation with IL-13 and after siRNA silencing of FLG expression. FLG and TJ genes and proteins were assessed by quantitative RT-PCR, Western blot analysis, and immunofluorescent staining. The biotinylation reagent diffused through the paracellular spaces of whole stratified epithelial layers in EoE biopsy samples. The TEER decreased in ALI-cultured HEECs after IL-13 stimulation. Although the protein level of FLG decreased, that of the TJ proteins increased in the mucosa of EoE biopsy samples and in ALI-cultured HEECs after IL-13 stimulation. IL-13 altered the staining patterns of TJ proteins and the epithelial morphology. FLG siRNA transfection significantly decreased TEER. The IL-13-mediated reduced esophageal barrier is associated with the altered expression pattern but not with the levels of TJ-associated proteins. A deficiency of FLG altered the stratified epithelial barrier. NEW & NOTEWORTHY Esophageal permeability to small molecules was increased in patients with eosinophilic esophagitis (EoE) and could be induced by IL-13 in our unique air-liquid interface-cultured primary multilayer human esophageal epithelial cells in vitro. A deficiency of filaggrin disrupted the esophageal stratified epithelial barrier. The decreased esophageal barrier in EoE was associated with the altered staining pattern of tight junction proteins, although the levels of the proteins themselves do not appear to be changed.

scholarly journals OP0245 MICROBIOTA-INDUCED INTESTINAL BARRIER DYSFUNCTION PRECEDES THE ONSET OF ARTHRITIS AND ALLOWS THE SHUTTLING OF IMMUNE CELLS FROM THE GUT THE JOINTS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 154.2-154
Author(s):  
M. Zaiss ◽  
N. Taijc ◽  
K. Sarter ◽  
V. Azizov ◽  
L. Bucci ◽  
...  
Keyword(s):  
Tight Junction ◽  
Tight Junctions ◽  
Immune Cells ◽  
Barrier Function ◽  
Intestinal Barrier ◽  
Intestinal Barrier Function ◽  
Barrier Dysfunction ◽  
Intestinal Barrier Dysfunction ◽  
Microbial Dysbiosis ◽  
Intestinal Dysbiosis

Background:While it is known that microbial dysbiosis is associated with the onset of rheumatoid arthritis, mechanistic insights how it facilitates the development of arthritis remained largely elusive to date. It is especially interesting how microbial dysbiosis affects the transition from asymptomatic autoimmunity to arthritis. We speculated that a breakdown of intestinal barrier function caused by microbial dysbiosis allows immune cells to shuttle from the gut to the joints.Objectives:To test whether intestinal barrier function is impaired before the onset of human RA and experimental arthritis and to seek for evidence that immune cells from the gut migrate to the joints.Methods:In a longitudinal cohort of RA-at risk individuals markers of disturbed intestinal barrier function, such as zonulin, were analysed and linked to RA onset. Furthermore, new-onset RA patients were assessed for gut leakiness and their intestinal biopsies for the expression of tight junction proteins and immune cell infiltration. In the murine model of collagen-induced arthritis, sequential analysis of intestinal dysbiosis, intestinal barrier function and arthritis onset was carried out. Additionally, barrier function was assessed on intestinal organoids exposed to faecal supernatants from eu- and dysbiotic mice with and without inhibition of zonulin. Furthermore, three types of interventions restoring intestinal barrier function were carried out for testing their effects on the inhibition of arthritis onset. Finally, photo- converted cells from the gut were traced in the joints to test for cellular trafficking from one to the other compartment.Results:Zonulin, a potent regulator for intestinal tight junctions, was elevated in autoimmune mice and men before the onset of arthritis and predicted the onset of human RA. Intestinal barrier functions as well as epithelial tight junctions were decreased before the onset of experimental arthritis and at onset of human RA. In mice, induction of autoimmunity was followed by rapid intestinal dysbiosis followed by gut leakiness before arthritis started. Faecal supernatants of arthritic mice induce epithelial barrier dysfunction in intestinal organoids in zonulin dependent manner. Restoration of the intestinal barrier in the pre-phase of arthritis using butyrate, CB1R agonist or zonulin antagonist larazotide inhibited the development of arthritis. Finally, using photoconvertible mice, gut-borne immune cells were identified that homed to the joints when barrier function was impaired.Conclusion:In summary, these data show the intestinal barrier dysfunction precedes the onset of RA and allows the trafficking of immune cells from the gut to the joints. Targeting of intestinal tight junction function may therefore allow preventing the onset of RA.Acknowledgments:Funded by the DFG-FOR2886 PANDORA, DFG–CRC118, Staedtler foundation, Johannes und Frieda Marohn-Stiftung, Else Kröner-Fresenius foundation, Interdisciplinary Centre for Clinical Research, Erlangen (IZKF), BMBF-MASCARA and the IMI funded projectRTCure.Disclosure of Interests:Mario Zaiss: None declared, Narges Taijc: None declared, Kerstin Sarter: None declared, Vugar Azizov: None declared, laura Bucci: None declared, Yubin Luo: None declared, Juan de Dios Cañete: None declared, francesco ciccia Grant/research support from: pfizer, novartis, roche, Consultant of: pfizer, novartis, lilly, abbvie, Speakers bureau: pfizer, novartis, lilly, abbvie, Georg Schett Speakers bureau: AbbVie, BMS, Celgene, Janssen, Eli Lilly, Novartis, Roche and UCB

scholarly journals Zinc ameliorates intestinal barrier dysfunctions in shigellosis by reinstating claudin-2 and -4 on the membranes

2019 ◽  
Vol 316 (2) ◽  
pp. G229-G246 ◽  
Author(s):  
Paramita Sarkar ◽  
Tultul Saha ◽  
Irshad Ali Sheikh ◽  
Subhra Chakraborty ◽  
Joydeep Aoun ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Tight Junction ◽  
Barrier Function ◽  
Intracellular Signaling ◽  
Ion Selectivity ◽  
Intestinal Lumen ◽  
Mouse Tissue ◽  
Barrier Dysfunction ◽  
Intracellular Location ◽  
Junction Protein

Whether zinc (Zn2+) regulates barrier functions by modulating tight-junction (TJ) proteins when pathogens such as Shigella alter epithelial permeability is still unresolved. We investigated the potential benefits of Zn2+ in restoring impaired barrier function in vivo in Shigella-infected mouse tissue and in vitro in T84 cell monolayers. Basolateral Shigella infection triggered a time-dependent decrease in transepithelial resistance followed by an increase in paracellular permeability of FITC-labeled dextran and altered ion selectivity. This led to ion and water loss into the intestinal lumen. Immunofluorescence studies revealed redistribution of claudin-2 and -4 to an intracellular location and accumulation of these proteins in the cytoplasm following infection. Zn2+ ameliorated this perturbed barrier by redistribution of claudin-2 and -4 back to the plasma membrane and by modulating the phosphorylation state of TJ proteins t hough extracellular signal-regulated kinase (ERK)1/2 dependency. Zn2+ prevents elevation of IL-6 and IL-8. Mice challenged with Shigella showed that oral Zn2+supplementation diminished diverse pathophysiological symptoms of shigellosis. Claudin-2 and -4 were susceptible to Shigella infection, resulting in altered barrier function and increased levels of IL-6 and IL-8. Zn2+ supplementation ameliorated this barrier dysfunction, and the inflammatory response involving ERK-mediated change of phosphorylation status for claudin-2 and -4. Thus, Zn2+ may have potential therapeutic value in inflammatory diarrhea and shigellosis. NEW & NOTEWORTHY Our study addresses whether Zn2+ could be an alternative strategy to reduce Shigella-induced inflammatory response and epithelial barrier dysfunction. We have defined a mechanism in terms of intracellular signaling pathways and tight-junction protein expression by Zn2+. Claudin-2 and -4 are susceptible to Shigella infection, whereas in the presence of Zn2+ they are resistant to infection-related barrier dysfunction involving ERK-mediated change of phosphorylation status of claudins.

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