scholarly journals PG-mediated closure of paracellular pathway and not restitution is the primary determinant of barrier recovery in acutely injured porcine ileum

2003 ◽  
Vol 285 (5) ◽  
pp. G967-G979 ◽  
Author(s):  
Jody L. Gookin ◽  
Joseph A. Galanko ◽  
Anthony T. Blikslager ◽  
Robert A. Argenzio

Small bowel epithelium is at the frontline of intestinal barrier function. Restitution is considered to be the major determinant of epithelial repair, because function recovers in parallel with restitution after acute injury. As such, studies of intact mucosa have largely been replaced by migration assays of cultured epithelia. These latter studies fail to account for the simultaneous roles played by villous contraction and paracellular permeability in recovery of barrier function. NSAIDs result in increased intestinal permeability and disease exacerbation in patients with inflammatory bowel disease (IBD). Thus we examined the reparative attributes of endogenous PGs after injury of ileal mucosa by deoxycholate (6 mM) in Ussing chambers. Recovery of transepithelial electrical resistance (TER) from 20-40 Ω·cm2 was abolished by indomethacin (Indo), whereas restitution of 40-100% of the villous surface was unaffected despite concurrent arrest of villous contraction. In the presence of PG, resident crypt and migrating epithelial cells were tightly apposed. In tissues treated with Indo, crypt epithelial cells had dilated intercellular spaces that were accentuated in the migrating epithelium. TER was fully rescued from the effects of Indo by osmotic-driven collapse of the paracellular space, and PG-mediated recovery was significantly impaired by blockade of Cl- secretion. These studies are the first to clearly distinguish the relative contribution of paracellular resistance vs. restitution to acute recovery of epithelial barrier function. Restitution was ineffective in the absence of PG-mediated paracellular space closure. Failure of PG-mediated repair mechanisms may underlie barrier failure resulting from NSAID use in patients with underlying enteropathy.

2020 ◽  
Vol 159 (5) ◽  
pp. 1763-1777.e14 ◽  
Author(s):  
Marianne R. Spalinger ◽  
Anica Sayoc-Becerra ◽  
Alina N. Santos ◽  
Ali Shawki ◽  
Vinicius Canale ◽  
...  

Pharmacology ◽  
2019 ◽  
Vol 105 (1-2) ◽  
pp. 102-108 ◽  
Author(s):  
Norio Nishii ◽  
Tadayuki Oshima ◽  
Min Li ◽  
Hirotsugu Eda ◽  
Kumiko Nakamura ◽  
...  

Introduction: Lubiprostone, a chloride channel activator, is said to reduce epithelial permeability. However, whether lubiprostone has a direct effect on the epithelial barrier function and how it modulates the intestinal barrier function remain unknown. Therefore, the effects of lubiprostone on intestinal barrier function were evaluated in vitro. Methods: Caco-2 cells were used to assess the intestinal barrier function. To examine the expression of claudins, immunoblotting was performed with specific antibodies. The effects of lubiprostone on cytokines (IFNγ, IL-6, and IL-1β) and aspirin-induced epithelial barrier disruption were assessed by transepithelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC) labeled-dextran permeability. Results: IFNγ, IL-6, IL-1β, and aspirin significantly decreased TEER and increased epithelial permeability. Lubiprostone significantly improved the IFNγ-induced decrease in TEER in a dose-dependent manner. Lubiprostone significantly reduced the IFNγ-induced increase in FITC labeled-dextran permeability. The changes induced by IL-6, IL-1β, and aspirin were not affected by lubiprostone. The expression of claudin-1, but not claudin-3, claudin-4, occludin, and ZO-1 was significantly increased by lubiprostone. Conclusion: Lubiprostone significantly improved the IFNγ-induced decrease in TEER and increase in FITC labeled-dextran permeability. Lubiprostone increased the expression of claudin-1, and this increase may be related to the effect of lubiprostone on the epithelial barrier function.


2019 ◽  
Vol 3 (s1) ◽  
pp. 13-13
Author(s):  
David R Hill ◽  
Roberto Cieza ◽  
Veda K. Yadagiri ◽  
Phillip Tarr ◽  
Jason R. Spence ◽  
...  

OBJECTIVES/SPECIFIC AIMS: The central goal of this proposal is to characterize the mechanisms that mediate success or failure of immature intestinal barrier in necrotizing enterocilitis. METHODS/STUDY POPULATION: To do this, I will utilize stem cell derived human intestinal organoids (HIOs), an innovative model of the immature intestine, and a cohort of bacterial isolates collected from premature infants who developed NEC to interrogate the cause-effect relationship of these strains on maintenance of the intestinal barrier. I hypothesize that the epithelial response to bacterial colonization is strain-dependent and results in differences in inflammatory signaling that shape epithelial barrier function in the immature intestine. RESULTS/ANTICIPATED RESULTS: Preliminary data shows that colonization of HIOs with different bacteria leads to species-specific changes in barrier function, and some species selectively damage the epithelial barrier while others enhance epithelial barrier function. I have identified key inflammatory signals that serve as central drivers of intestinal barrier function. DISCUSSION/SIGNIFICANCE OF IMPACT: Characterization of this process is expected to substantially advance scientific understanding of early events in NEC pathogenesis and lead to new opportunities for targeted therapeutic intervention to accelerate barrier maturation or prevent hyperinflammatory reactivity in the neonatal intestine. The research proposed in this application represents an entirely novel approach to studying host-microbial interactions in the immature. Conceptually, this novel translational approach will help to define the pivotal role of colonizing bacteria in initiating epithelial inflammation in NEC patients.


2018 ◽  
Vol 314 (2) ◽  
pp. G247-G255 ◽  
Author(s):  
Cristina Pardo-Camacho ◽  
Ana M González-Castro ◽  
Bruno K Rodiño-Janeiro ◽  
Marc Pigrau ◽  
María Vicario

As the largest interface between the outside and internal milieu, the intestinal epithelium constitutes the first structural component facing potential luminal threats to homeostasis. This single-cell layer is the epicenter of a tightly regulated communication network between external and internal factors that converge to prime defensive responses aimed at limiting antigen penetration and the maintenance of intestinal barrier function. The defensive role developed by intestinal epithelial cells (IEC) relies largely on the variety of receptors they express at both extracellular (apical and basolateral) and intracellular compartments, and the capacity of IEC to communicate with immune and nervous systems. IEC recognize pathogen-associated molecules by innate receptors that promote the production of mucus, antimicrobial substances, and immune mediators. Epithelial cells are key to oral tolerance maintenance and also participate in adaptive immunity through the expression of immunoglobulin (Ig) receptors and by promoting local Ig class switch recombination. In IEC, different types of antigens can be sensed by multiple immune receptors that share signaling pathways to assure effective responses. Regulated defensive activity maintains intestinal homeostasis, whereas a breakdown in the control of epithelial immunity can increase the intestinal passage of luminal content and microbial invasion, leading to inflammation and tissue damage. In this review, we provide an updated overview of the type of immune receptors present in the human intestinal epithelium and the responses generated to promote effective barrier function and maintain mucosal homeostasis.


2006 ◽  
Vol 291 (5) ◽  
pp. G885-G894 ◽  
Author(s):  
Adam J. Moeser ◽  
Prashant K. Nighot ◽  
Kathleen A. Ryan ◽  
Jenna G. Wooten ◽  
Anthony T. Blikslager

Prostaglandins stimulate repair of the ischemia-injured intestinal barrier in the porcine ileum through a mechanism involving cAMP-dependent Cl− secretion and inhibition of electroneutral Na+/H+ exchanger (NHE) activity. In the present study, we focused on the role of individual NHE isoforms in the recovery of barrier function. Ischemia-injured porcine ileal mucosa was mounted on Ussing chambers. Short-circuit current ( Isc), transepithelial electrical resistance (TER), and isotopic fluxes of 22Na were measured in response to PGE2 and selective inhibitors of epithelial NHE isoforms. Immunoassays were used to assess the expression of NHE isoforms. Forty-five minutes of intestinal ischemia resulted in a 45% reduction in TER ( P < 0.01). Near-complete restitution occurred within 60 min. Inhibition of NHE2 with HOE-694 (25 μM) added to the mucosal surface of the injured ileum stimulated significant elevations in TER, independent of changes in Isc and histological evidence of restitution. Pharmacological inhibition of NHE3 or NHE1 with mucosal S-3226 (20 μM) or serosal cariporide (25 μM), respectively, had no effect. Ischemia-injured tissues treated with mucosal S-3226 or HOE-694 exhibited equivalent reductions in mucosal-to-serosal fluxes of 22Na+ (by ∼35%) compared with nontreated ischemia-injured control tissues ( P < 0.05). Intestinal ischemia resulted in increased expression of the cytoplasmic NHE regulatory factor EBP50 in NHE2 but not in NHE3 immunoprecipitates. Selective inhibition of NHE2, and not NHE3, induces recovery of barrier function in the ischemia-injured intestine.


Pharmacology ◽  
2013 ◽  
Vol 91 (1-2) ◽  
pp. 104-111 ◽  
Author(s):  
Reiko Akagi ◽  
Michiko Ohno ◽  
Kiminori Matsubara ◽  
Mitsuaki Fujimoto ◽  
Akira Nakai ◽  
...  

2021 ◽  
Vol 8 ◽  
Author(s):  
Tasuku Ogita ◽  
Fu Namai ◽  
Ayane Mikami ◽  
Takahiro Ishiguro ◽  
Koji Umezawa ◽  
...  

The maintenance of intestinal homeostasis is necessary for a good quality of life, and strengthening of the intestinal barrier function is thus an important issue. Therefore, we focused on soybean resistant protein (SRP) derived from kori-tofu (freeze-dried tofu), which is a traditional Japanese food, as a functional food component. In this study, to investigate the effect of SRP on the intestinal barrier function and intestinal microbiota, we conducted an SRP free intake experiment in mice. Results showed that ingestion of SRP decreased the serum level of lipopolysaccharide-binding protein and induced the expression of Reg3γ, thereby improving the intestinal barrier function. In addition, SRP intake induced changes in the cecal microbiota, as observed by changes in β-diversity. In particular, in the microbiota, the up-regulation of functional gene pathways related to the bacterial invasion of epithelial cells (ko05100) was observed, suggesting that Reg3γ expression was induced by the direct stimulation of epithelial cells. The results of this study suggest that SRP is a functional food component that may contribute to the maintenance of intestinal homeostasis.


2018 ◽  
Vol 48 (3) ◽  
pp. 1188-1200 ◽  
Author(s):  
Tanzhou Chen ◽  
Ruoyang Lin ◽  
Sisi Jin ◽  
Renpin Chen ◽  
Haibo Xue ◽  
...  

Background/Aims: Epithelial cells line the intestinal mucosa and form an important barrier for maintaining host health. This study aimed to explore the mechanism of the Sphingosine-1-phosphate (S1P)/Sphingosine-1-phosphate receptor 2 (S1PR2) pathway in intestinal epithelial cells (IECs) that participate in the intestinal barrier function. Methods: In this study, we constructed a knockout of the S1PR2 gene in mice, and Dextra sulfate sodium (DSS) was used to induce colitis. We isolated IECs from wild type (WT) and S1PR2–/– mice, and the endogenous expression of S1PR2 and Zonula occludens 1 (ZO-1) in IEC were detected by Western blot. Next, the major histocompatibility complex II (MHC-II) expression was analyzed by reverse transcription quantitative real-time (RT-qPCR) and flow cytometry. The in vivo and in vitro intestinal permeability were evaluated by serum fluorescein isothiocyanate (FITC) concentration. The tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interferon-γ (IFN-γ) levels in cell suspension were analyzed by enzyme-linked immuno sorbent assay (ELISA). A carboxyfluorescein diacetate succinimidyl ester (CFSE) assay was used to detect the T-cell proliferation in a co-culture system. Results: The intestinal mucosal barrier damage in S1PR2–/– mice was more severe than in the WT mice, and there were more CD4+T-cells in the colon tissue of DSS-treated S1PR2–/– mice. Either the mouse colon carcinoma cell line (CT26. WT) or the IECs upregulated MHC-II expression, which then promoted CD4+T-cell proliferation. The S1P/S1PR2 pathway controlled MHC-II expression to regulate CD4+T-cell proliferation via the extracellular signal-regulated kinase (ERK) pathway. In addition, the IFN-γ that was secreted by CD4+T-cells increased DSS-induced damage of intestinal epithelial cell barrier function. ZO-1 expression was increased by S1P in CT26.WT cells, while S1PR2 antagonist JTE-013 expression was downregulated. However, in CT26.WTsi-S1PR2 cells, S1P had no effect on ZO-1 expression. Conclusions: The S1P/S1PR2 axis in IECs mediated CD4+T-cell activation via the ERK pathway and MHC-II expression to regulate intestinal barrier function.


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