scholarly journals IL-1 stimulates ceramide accumulation without inducing apoptosis in intestinal epithelial cells

2002 ◽  
Vol 11 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Fadia R. Homaidan ◽  
Marwan E. El-Sabban ◽  
Iman Chakroun ◽  
Mirvat El-Sibai ◽  
Ghassan S. Dbaibo
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Interleukin 1 ◽  
Nuclear Staining ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
Concentration Dependent Manner ◽  
M Phase ◽  
Induced Apoptosis ◽  
Ceramide Accumulation

Background: In inflammatory bowel disease (IBD), cytokine levels (such as interleukin-1 (IL-1)) are elevated. We have shown previously that IL-1 activates phospholipid signaling pathways in intestinal epithelial cells (IEC), leading to increased ceramide levels.Aim: To determine whether ceramide induces apoptosis in IEC.Methods: Apoptosis was evaluated by annexin-Vbinding or Hoechst nuclear staining. Levels of bcl-2, bcl-x, bax, p53 and p21 were determined by Western blotting, and cell cycle analysis was determined by flow cytometry.Results: IL-1 increased ceramide accumulation in a time-dependent and concentration-dependent manner with a peak response at 4 h, with [IL-1] = 30 ng/ml. Neither IL-1 nor ceramide induced apoptosis in IEC, but they increased bcl-2 levels and decreased bax and p21 levels without affecting bcl-x and p53 levels. They also caused a slight but significant increase in the G2/M phase. These data suggest a role for ceramide in IBD and suggest a possible mechanism for the enhanced tumorigenic activity in IBD patients.

Effects of Stearic Acid on Proliferation, Differentiation, Apoptosis, and Autophagy in Porcine Intestinal Epithelial Cells

2020 ◽  
Vol 20 (2) ◽  
pp. 157-166
Author(s):  
Yuan Yang ◽  
Jin Huang ◽  
Jianzhong Li ◽  
Huansheng Yang ◽  
Yulong Yin
Keyword(s):  
Cell Differentiation ◽  
Epithelial Cells ◽  
Stearic Acid ◽  
Er Stress ◽  
Intestinal Epithelial Cells ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
High Concentrations ◽  
Induced Apoptosis ◽  
Dose Dependent

Background: Stearic acid (SA), a saturated long-chain fatty acid consisting of 18 carbon atoms, is widely found in feed ingredients, such as corn, soybeans, and wheat. However, the roles of SA in the renewal of intestinal epithelial cells remain unclear. Methods and Results: In the present study, we found that 0.01-0.1 mM SA promoted IPEC-J2 cell differentiation and did not affect IPEC-J2 cell viability. In addition, the results showed that the viability of IPEC-J2 cells was inhibited by SA in a time- and dose-dependent manner at high concentrations. Flow cytometry and western blot analysis suggested that SA induced apoptosis, autophagy and ER stress in cells. In addition, the amounts of triglyceride were significantly increased upon challenge with SA. Moreover, the decrease in the viability of cells induced by SA could be attenuated by 4-PBA, an inhibitor of ER stress. Conclusion: In summary, SA accelerated IPEC-J2 cell differentiation at 0.01-0.1 mM. Furthermore, SA induced IPEC-J2 cell apoptosis and autophagy by causing ER stress.

scholarly journals Bacteroides fragilis Enterotoxin Upregulates Matrix Metalloproteinase-7 Expression through MAPK and AP-1 Activation in Intestinal Epithelial Cells, Leading to Syndecan-2 Release

2021 ◽  
Vol 22 (21) ◽  
pp. 11817
Author(s):  
Jong Ik Jeon ◽  
Keun Hwa Lee ◽  
Jung Mogg Kim
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Intestinal Barrier ◽  
Bacteroides Fragilis ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
Concentration Dependent Manner ◽  
Activation Of Transcription ◽  
Mitogen Activated Protein ◽  
Matrix Metalloproteinase 7

Bacteroides fragilis enterotoxin (BFT) produced by enterotoxigenic B. fragilis (ETBF) causes colonic inflammation. BFT initially contacts intestinal epithelial cells (IECs) and affects the intestinal barrier. Although molecular components of the gut epithelial barrier such as metalloproteinase-7 (MMP-7) and syndecan-2 are known to be associated with inflammation, little has been reported about MMP-7 expression and syndecan-2 shedding in response to ETBF infection. This study explores the role of BFT in MMP-7 induction and syndecan-2 release in IECs. Stimulating IECs with BFT led to the induction of MMP-7 and the activation of transcription factors such as NF-κB and AP-1. MMP-7 upregulation was not affected by NF-κB, but it was related to AP-1 activation. In BFT-exposed IECs, syndecan-2 release was observed in a time- and concentration-dependent manner. MMP-7 suppression was associated with a reduction in syndecan-2 release. In addition, suppression of ERK, one of the mitogen-activated protein kinases (MAPKs), inhibited AP-1 activity and MMP-7 expression. Furthermore, the suppression of AP-1 and ERK activity was related to the attenuation of syndecan-2 release. These results suggest that a signaling cascade comprising ERK and AP-1 activation in IECs is involved in MMP-7 upregulation and syndecan-2 release during exposure to BFT.

scholarly journals Positive cross talk between protein kinase D and β-catenin in intestinal epithelial cells: impact on β-catenin nuclear localization and phosphorylation at Ser552

2016 ◽  
Vol 310 (7) ◽  
pp. C542-C557 ◽  
Author(s):  
Jia Wang ◽  
Liang Han ◽  
James Sinnett-Smith ◽  
Li-Li Han ◽  
Jan V. Stevens ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Epithelial Cells ◽  
Transgenic Mice ◽  
Nuclear Localization ◽  
Cross Talk ◽  
Intestinal Epithelial Cells ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
Ang Ii ◽  
Potent Inducer

Given the fundamental role of β-catenin signaling in intestinal epithelial cell proliferation and the growth-promoting function of protein kinase D1 (PKD1) in these cells, we hypothesized that PKDs mediate cross talk with β-catenin signaling. The results presented here provide several lines of evidence supporting this hypothesis. We found that stimulation of intestinal epithelial IEC-18 cells with the G protein-coupled receptor (GPCR) agonist angiotensin II (ANG II), a potent inducer of PKD activation, promoted endogenous β-catenin nuclear localization in a time-dependent manner. A significant increase was evident within 1 h of ANG II stimulation ( P < 0.01), peaked at 4 h ( P < 0.001), and declined afterwards. GPCR stimulation also induced a marked increase in β-catenin-regulated genes and phosphorylation at Ser552 in intestinal epithelial cells. Exposure to preferential inhibitors of the PKD family (CRT006610 or kb NB 142-70) or knockdown of the isoforms of the PKD family prevented the increase in β-catenin nuclear localization and phosphorylation at Ser552 in response to ANG II. GPCR stimulation also induced the formation of a complex between PKD1 and β-catenin, as shown by coimmunoprecipitation that depended on PKD1 catalytic activation, as it was abrogated by cell treatment with PKD family inhibitors. Using transgenic mice that express elevated PKD1 protein in the intestinal epithelium, we detected a marked increase in the localization of β-catenin in the nucleus of crypt epithelial cells in the ileum of PKD1 transgenic mice, compared with nontransgenic littermates. Collectively, our results identify a novel cross talk between PKD and β-catenin in intestinal epithelial cells, both in vitro and in vivo.

Sequential and rapid activation of select caspases during apoptosis of normal intestinal epithelial cells

1998 ◽  
Vol 274 (6) ◽  
pp. G1117-G1124 ◽  
Author(s):  
Johannes Grossmann ◽  
Susanne Mohr ◽  
Eduardo G. Lapetina ◽  
Claudio Fiocchi ◽  
Alan D. Levine
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Cysteine Proteases ◽  
Intestinal Epithelial ◽  
Caspase Activation ◽  
High Turnover ◽  
Sequential Activation ◽  
Caspase 6 ◽  
Caspase Substrate ◽  
Induced Apoptosis

Detachment-induced cell death (DICD) is considered to be one of the means by which intestinal epithelial cells (IEC) die of apoptosis as they reach the lumen and are shed. Caspases, a family of cysteine proteases, play a central role in initiating, amplifying, and executing apoptosis; however, the pattern of caspase activation in response to distinct apoptotic stimuli remains unknown. We investigated the kinetics of caspase activation during DICD in freshly isolated human IEC. DNA fragmentation is observed 90 min after detachment and is preceded by the sequential activation of preformed members of the CPP32 family of caspases. Activation of caspase 6 and cleavage of the endogenous caspase substrate poly(ADP-ribose) polymerase (EC 2.4.2.30 ) are detected within 15 min of detachment, 30–45 min before caspase 3 activation. Caspase 1 and caspase 10 are present as proenzymes, yet they remain inactive in response to this trigger of apoptosis. Human IEC are primed to rapidly undergo detachment-induced apoptosis involving the selective and sequential activation of preformed caspases. This study may enhance our understanding of physiological events occurring as IEC are shed. Their rapid apoptotic response to detachment may facilitate the high turnover of cells and ensure homeostasis in the intestinal epithelium.

scholarly journals Lipid rafts mediate internalization of β1-integrin in migrating intestinal epithelial cells

2008 ◽  
Vol 295 (5) ◽  
pp. G965-G976 ◽  
Author(s):  
Elena V. Vassilieva ◽  
Kirsten Gerner-Smidt ◽  
Andrei I. Ivanov ◽  
Asma Nusrat
Keyword(s):  
Epithelial Cells ◽  
Lipid Rafts ◽  
Lipid Raft ◽  
Intestinal Epithelial Cells ◽  
Focal Adhesions ◽  
Endocytic Pathway ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
Caveolin 1 ◽  
Cell Matrix

Intestinal mucosal inflammation is associated with epithelial wounds that rapidly reseal by migration of intestinal epithelial cells (IECs). Cell migration involves cycles of cell-matrix adhesion/deadhesion that is mediated by dynamic turnover (assembly and disassembly) of integrin-based focal adhesions. Integrin endocytosis appears to be critical for deadhesion of motile cells. However, mechanisms of integrin internalization during remodeling of focal adhesions of migrating IECs are not understood. This study was designed to define the endocytic pathway that mediates internalization of β1-integrin in migrating model IECs. We observed that, in SK-CO15 and T84 colonic epithelial cells, β1-integrin is internalized in a dynamin-dependent manner. Pharmacological inhibition of clathrin-mediated endocytosis or macropinocytosis and small-interfering RNA (siRNA)-mediated knock down of clathrin did not prevent β1-integrin internalization. However, β1-integrin internalization was inhibited following cholesterol extraction and after overexpression of lipid raft protein, caveolin-1. Furthermore, internalized β1-integrin colocalized with the lipid rafts marker cholera toxin, and siRNA-mediated knockdown of caveolin-1 and flotillin-1/2 increased β1-integrin endocytosis. Our data suggest that, in migrating IEC, β1-integrin is internalized via a dynamin-dependent lipid raft-mediated pathway. Such endocytosis is likely to be important for disassembly of integrin-based cell-matrix adhesions and therefore in regulating IEC migration and wound closure.

Comparison of gene expression and activation of transcription factors in organoid-derived monolayer intestinal epithelial cells and organoids

2021 ◽  
Author(s):  
Yu Takahashi ◽  
Yu Inoue ◽  
Keitaro Kuze ◽  
Shintaro Sato ◽  
Makoto Shimizu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Epithelial Cells ◽  
Gene Expression Regulation ◽  
Intestinal Epithelial Cells ◽  
Three Dimensional ◽  
Culture Conditions ◽  
Dependent Manner ◽  
Intestinal Epithelial

Abstract Intestinal organoids better represent in vivo intestinal properties than conventionally used established cell lines in vitro. However, they are maintained in three-dimensional culture conditions that may be accompanied by handling complexities. We characterized the properties of human organoid-derived two-dimensionally cultured intestinal epithelial cells (IECs) compared with those of their parental organoids. We found that the expression of several intestinal markers and functional genes were indistinguishable between monolayer IECs and organoids. We further confirmed that their specific ligands equally activate intestinal ligand-activated transcriptional regulators in a dose-dependent manner. The results suggest that culture conditions do not significantly influence the fundamental properties of monolayer IECs originating from organoids, at least from the perspective of gene expression regulation. This will enable their use as novel biological tools to investigate the physiological functions of the human intestine.

scholarly journals Interferon-γ inhibits sirtuin 6 gene expression in intestinal epithelial cells through a microRNA-92b-dependent mechanism

2020 ◽  
Vol 318 (4) ◽  
pp. C732-C739
Author(s):  
Fangyi Liu ◽  
Xiao Wang ◽  
Hua Geng ◽  
Heng-Fu Bu ◽  
Peng Wang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Protein Expression ◽  
Intestinal Epithelial Cells ◽  
Specific Inhibitor ◽  
In Silico Analysis ◽  
Interferon Γ ◽  
Luciferase Assay ◽  
Epithelial Cell Line ◽  
Dependent Manner ◽  
Intestinal Epithelial

Sirtuin 6 (Sirt6) is predominantly expressed in epithelial cells in intestinal crypts. It plays an important role in protecting intestinal epithelial cells against inflammatory injury. Previously, we found that colitis is associated with the downregulation of Sirt6 protein in the intestines. Here, we report that murine interferon-γ (Ifnγ) inhibits Sirt6 protein but not mRNA expression in young adult mouse colonocytes (YAMC, a mouse colonic epithelial cell line) in a dose- and time-dependent manner. Using microRNA array analysis, we showed that Ifnγ induces expression of miR-92b in YAMC cells. With in silico analysis, we found that the Sirt6 3′-untranslated region (UTR) contains a putative binding site for miR-92b. Luciferase assay showed that Ifnγ inhibited Sirt6 3′-UTR activity and this effect was mimicked by miR-92b via directly targeting the miR-92b seed site in the 3′-UTR of Sirt6 mRNA. Furthermore, Western blot demonstrated that miR-92b downregulated Sirt6 protein expression in YAMC cells. Blocking miR-92b with a specific inhibitor attenuated the inhibitory effect of Ifnγ on Sirt6 protein expression in the cells. Collectively, our data suggest that Ifnγ inhibits Sirt6 protein expression in intestinal epithelial cells via a miR-92b-mediated mechanism. miR-92b may be a novel therapeutic target for rescuing Sirt6 protein levels in intestinal epithelial cells, thereby protecting against intestinal mucosal injury caused by inflammation.

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