scholarly journals Stress granule formation mediates the inhibition of colonic Hsp70 translation by interferon-γ and tumor necrosis factor-α

2010 ◽  
Vol 298 (4) ◽  
pp. G481-G492 ◽  
Author(s):  
Shien Hu ◽  
Erika C. Claud ◽  
Mark W. Musch ◽  
Eugene B. Chang
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Interferon Γ ◽  
Stress Granule ◽  
Intestinal Epithelial ◽  
Granule Formation ◽  
Tnf Α ◽  
Ifn Γ ◽  
Factor Α ◽  
Necrosis Factor

Mucosal inflammation, through cytokines such as interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α), has many effects on the intestinal epithelium, including selective translational inhibition of the cytoprotective protein heat shock protein 70 (Hsp70). To further elucidate the mechanisms underlying this effect, we examined the role of stress granules in mediating the actions of these proinflammatory cytokines. Using conditionally immortalized young adult mouse colonic epithelial cells, we demonstrate that IFN-γ and TNF-α, which upregulate eukaryotic initiation factor-α (eIF-2α) phosphorylation and reduce Hsp70 translation, significantly enhance stress granule formation in heat-shocked intestinal epithelial cells. The IFN-γ and TNF-α effects in upregulation of stress granule formation and downregulation of Hsp70 were eIF-2α dependent, and the effect could be negated by blocking eIF-2α phosphorylation with use of an RNA-dependent protein kinase inhibitor. Correspondingly, IFN-γ and TNF-α increased binding of cytoplasmic proteins to the 3′-untranslated region of Hsp70 mRNA, suggesting specific recruitment of Hsp70 to stress granules as the mechanism of IFN-γ and TNF-α inhibition of Hsp70 translation. We thus report a novel linkage between inflammatory cytokine production, stress granule formation, and Hsp70 translation inhibition, providing additional insights into the response of intestinal epithelial cells to inflammatory stress.

Inflammatory cytokine TNF-α inhibits Na+–glutamine cotransport in intestinal epithelial cells

2013 ◽  
Vol 91 (4) ◽  
pp. 275-284 ◽  
Author(s):  
Jamilur R. Talukder ◽  
Brittney Boyd ◽  
Ashley Griffin ◽  
Antara Jaima ◽  
Vazhaikkurichi M. Rajendran
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Kinetic Studies ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
Cell Integrity ◽  
Tnf Α ◽  
Factor Α ◽  
Necrosis Factor

Glutamine (Gln), a preferred fuel source for enterocytes, is critical for intestinal epithelial cell integrity and barrier function. Chronic enteritis inhibits apical Na+–Gln cotransport. It is not known whether inflammatory cytokines that are secreted during inflammation inhibit Na+–Gln cotransport. Thus, this study aimed to examine whether TNF-α would affect apical Na+–Gln cotransport in intestinal epithelial cells. In this study, the presence of Na+–Gln cotransport was established by measuring Gln uptake in 10 days postconfluent IEC-6 cells grown on transwell plates. Cation, amino acid specificity, and siRNA transfection studies established that Na+–Gln cotransport is mediated via B0AT1. Immunoblotting and immunofluorescence studies established the apical membrane localization of B0AT1 in IEC-6 cells. Tumour necrosis factor α (TNF-α) inhibited Na+–Gln cotransport in a concentration- and time-dependent manner with an inhibitory concentration of 1.53 nmol·L−1. Quantitative real-time PCR and Western blot analyses indicated that TNF-α did not alter B0AT1-specific transcripts or protein expression level. Kinetic studies revealed that TNF-α inhibited Na+–Gln cotransport by reducing the affinity of the cotransporters for Gln, and this effect was antagonized by genistein. Thus, we conclude that the TNF-α inhibition of Na+–Gln cotransport occurs at the post-translational level, and that the IEC-6 cell line is an excellent system to study the role of cytokines in Na+–Gln cotransport.

Proinflammatory cytokines TNF-α and IFN-γ alter laminin expression under an apoptosis-independent mechanism in human intestinal epithelial cells

2004 ◽  
Vol 287 (3) ◽  
pp. G592-G598 ◽  
Author(s):  
Caroline Francoeur ◽  
Fabrice Escaffit ◽  
Pierre H. Vachon ◽  
Jean-François Beaulieu
Keyword(s):  
Growth Factor ◽  
Epithelial Cells ◽  
Proinflammatory Cytokines ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Laminin 5 ◽  
Cell Functions ◽  
Tnf Α ◽  
Independent Mechanism ◽  
Ifn Γ

Laminins are basement membrane molecules that mediate cell functions such as adhesion, proliferation, migration, and differentiation. In the normal small intestine, laminin-5 and -10 are mainly expressed at the base of villus cells. However, in Crohn's disease (CD), a major redistribution of these laminins to the crypt region of the inflamed ileal mucosa has been observed, suggesting a possible relationship between laminin expression and cytokine and/or growth factor production, which is also altered in CD. The aim of this study was to test the hypothesis that proinflammatory cytokines can modulate laminin expression by intestinal epithelial cells. The effect of TNF-α, IFN-γ, IL-1β, IL-6, and transforming growth factor (TGF)-β was analyzed on the expression of laminins in the normal human intestinal epithelial crypt (HIEC) cell line. When treated with a single cytokine, HIEC cells secreted small amounts of laminin-5 and -10. Only TNF-α and TGF-β induced a slight increase in the secretion of these laminins. However, in combination, TNF-α and IFN-γ synergistically stimulated the secretion of both laminin-5 and -10 in HIEC cells. Transcript analyses suggested that the upregulation of the two laminins might depend on distinct mechanisms. Interestingly, the TNF-α and IFN-γ combination was also found to significantly promote apoptosis. However, the effect of cytokines on the secretion of laminins was maintained even after completely blocking apoptosis by inhibiting caspase activities. These results demonstrate that laminin production is specifically modulated by the proinflammatory cytokines TNF-α and IFN-γ in intestinal epithelial cells under an apoptosis-independent mechanism.

TNF-α and IFN-γ regulate the expression of the NOD2 (CARD15) gene in human intestinal epithelial cells

2003 ◽  
Vol 124 (4) ◽  
pp. 1001-1009 ◽  
Author(s):  
Philip Rosenstiel ◽  
Massimo Fantini ◽  
Karen Bräutigam ◽  
Tanja Kühbacher ◽  
Georg H. Waetzig ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Human Intestinal Epithelial Cells ◽  
Tnf Α ◽  
Ifn Γ ◽  
Card15 Gene

Systemic Sclerosis Fibroblasts Show Specific Alterations of Interferon-γ and Tumor Necrosis Factor-α-induced Modulation of Interleukin 6 and Chemokine Ligand 2

2012 ◽  
Vol 39 (5) ◽  
pp. 979-985 ◽  
Author(s):  
ALESSANDRO ANTONELLI ◽  
POUPAK FALLAHI ◽  
SILVIA MARTINA FERRARI ◽  
DILIA GIUGGIOLI ◽  
MICHELE COLACI ◽  
...  
Keyword(s):  
Systemic Sclerosis ◽  
Tumor Necrosis Factor ◽  
Interleukin 6 ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Interferon Γ ◽  
Tnf Α ◽  
Ifn Γ ◽  
Factor Α ◽  
Necrosis Factor

Objective.We evaluated the effect of interferon-γ (IFN-γ) and/or tumor necrosis factor-α (TNF-α) on the secretion of prototype proinflammatory cytokine interleukin 6 (IL-6), compared to T-helper 1 [Th1; chemokine (C-X-C motif) ligand 10 (CXCL10)] or Th2 [chemokine (C-C motif) ligand 2 (CCL2)] chemokines, in primary cultured fibroblasts from patients with systemic sclerosis (SSc) at an early stage of the disease.Methods.Fibroblast cultures from 5 SSc patients (disease duration < 2 yrs) and 5 healthy controls were evaluated for the production of IL-6, CXCL10, and CCL2 at the basal level and after stimulation with IFN-γ and/or TNF-α.Results.SSc fibroblasts basally produced higher levels of IL-6 than controls, while no difference was observed about CCL2 and CXCL10. TNF-α was able to dose-dependently induce IL-6 and CCL2 secretion in SSc, but not in control fibroblasts. By stimulation with increasing doses of IFN-γ, SSc fibroblasts were induced to secrete CCL2 and CXCL10, while no effect was observed on IL-6. The combination of IFN-γ and TNF-α induced a strong secretion of IL-6 and CCL2 in SSc fibroblasts but not in controls. In contrast, the synergistic effect of IFN-γ and TNF-α on CXCL10 secretion was similar in SSc fibroblasts and in controls.Conclusion.SSc fibroblasts participate in the self-perpetuation of inflammation by releasing IL-6, CXCL10, and CCL2 under the influence of IFN-γ and/or TNF-α. SSc fibroblasts are more active than controls in the secretion of IL-6 at baseline, and in the production of IL-6 and CCL2 under the combined IFN-γ/TNF-α stimulation.

scholarly journals Proinflammatory cytokines tumor necrosis factor-α and interferon-γ alter tight junction structure and function in the rat parotid gland Par-C10 cell line

2008 ◽  
Vol 295 (5) ◽  
pp. C1191-C1201 ◽  
Author(s):  
Olga J. Baker ◽  
Jean M. Camden ◽  
Robert S. Redman ◽  
Jonathan E. Jones ◽  
Cheikh I. Seye ◽  
...  
Keyword(s):  
Receptor Agonist ◽  
Interferon Γ ◽  
Anion Secretion ◽  
Cell Monolayers ◽  
Tnf Α ◽  
Rat Parotid Gland ◽  
Ifn Γ ◽  
Rat Parotid ◽  
Factor Α ◽  
Necrosis Factor

Sjögren's syndrome (SS) is an autoimmune disorder characterized by inflammation and dysfunction of salivary glands, resulting in impaired secretory function. The production of the proinflammatory cytokines tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) is elevated in exocrine glands of patients with SS, although little is known about the effects of these cytokines on salivary epithelial cell functions necessary for saliva secretion, including tight junction (TJ) integrity and the establishment of transepithelial ion gradients. The present study demonstrates that chronic exposure of polarized rat parotid gland (Par-C10) epithelial cell monolayers to TNF-α and IFN-γ decreases transepithelial resistance (TER) and anion secretion, as measured by changes in short-circuit current ( Isc) induced by carbachol, a muscarinic cholinergic receptor agonist, or UTP, a P2Y2 nucleotide receptor agonist. In contrast, TNF-α and IFN-γ had no effect on agonist-induced increases in the intracellular calcium concentration [Ca2+]i in Par-C10 cells. Furthermore, treatment of Par-C10 cell monolayers with TNF-α and IFN-γ increased paracellular permeability to normally impermeant proteins, altered cell and TJ morphology, and downregulated the expression of the TJ protein, claudin-1, but not other TJ proteins expressed in Par-C10 cells. The decreases in TER, agonist-induced transepithelial anion secretion, and claudin-1 expression caused by TNF-α, but not IFN-γ, were reversible by incubation of Par-C10 cell monolayers with cytokine-free medium for 24 h, indicating that IFN-γ causes irreversible inhibition of cellular activities associated with fluid secretion in salivary glands. Our results suggest that cytokine production is an important contributor to secretory dysfunction in SS by disrupting TJ integrity of salivary epithelium.

TNF-α and IFN-γ regulate the expression of the NOD2 (CARD15) gene in human intestinal epithelial cells

2003 ◽  
Vol 124 (4) ◽  
pp. A111 ◽  
Author(s):  
Philip Rosenstiel ◽  
Massimo Fantini ◽  
Karen Braeutigam ◽  
Georg Waetzig ◽  
Tanja Kuehbacher ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Human Intestinal Epithelial Cells ◽  
Tnf Α ◽  
Ifn Γ ◽  
Card15 Gene

scholarly journals Regulation of NF-κB responses by epigenetic suppression of IκBα expression in HCT116 intestinal epithelial cells

2010 ◽  
Vol 299 (1) ◽  
pp. G96-G105 ◽  
Author(s):  
Angela O'Gorman ◽  
Amy Colleran ◽  
Aideen Ryan ◽  
Jelena Mann ◽  
Laurence John Egan
Keyword(s):  
Epithelial Cells ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Intestinal Epithelial Cells ◽  
Gene Promoter ◽  
Intestinal Epithelial ◽  
Epigenetic Factors ◽  
Factor Α ◽  
Necrosis Factor ◽  
Hct116 Cells

Intestinal epithelial cells play critical roles in regulating mucosal immunity. Since epigenetic factors such as DNA methylation and histone modifications are implicated in aging, carcinogenesis, and immunity, we set out to assess any role for epigenetic factors in the regulation of intestinal epithelial cell immune responses. Experiments were conducted using the HCT116 cell line, and a subclone was genetically engineered to lack DNA methyltransferases (DNMT). The induction of the chemokine interleukin-8 and the antiapoptotic protein cFLIP by tumor necrosis factor-α were markedly less in HCT116 cells lacking DNMT than in parental cells. These effects were accompanied by lower monocyte chemotaxis and higher caspase signaling in HCT116 cells lacking DNMT than parental cells. Tumor necrosis factor-α-induced NF-κB activation was blocked and IκBα expression was higher in HCT116 cells lacking DNMT than in parental cells. A CpG island in the IκBα gene promoter region was found to contain variable levels of methylation in parental HCT116 cells. Chromatin immunoprecipitation analysis of histone proteins bound to the IκBα gene promoter revealed that higher levels of IκBα expression in HCT116 cells lacking DNMT compared with parental cells were accompanied by more chromatin marks permissive to gene transcription. These findings show that epigenetic factors influence the NF-κB system in intestinal epithelial cells, resulting in a previously unrecognized mechanism of innate immune regulation.

scholarly journals Inhibition of the NF-κB Pathway in Human Intestinal Epithelial Cells by Commensal Streptococcus salivarius

2011 ◽  
Vol 77 (13) ◽  
pp. 4681-4684 ◽  
Author(s):  
Ghalia Kaci ◽  
Omar Lakhdari ◽  
Joël Doré ◽  
S. Dusko Ehrlich ◽  
Pierre Renault ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Streptococcus Salivarius ◽  
Necrosis Factor Alpha ◽  
Content Type ◽  
Human Intestinal Epithelial Cells ◽  
Tnf Α ◽  
Factor Alpha ◽  
Necrosis Factor

ABSTRACTStreptococcus salivariusexhibited an anti-inflammatory effect on intestinal epithelial cells (IECs) and monocytes. Strains were screened using a reporter clone, HT-29/kB-luc-E, induced by tumor necrosis factor alpha (TNF-α). Supernatant from each strain downregulated NF-κB activation. The two most efficient strains produced an active metabolite (<3 kDa) which was able to downregulate the secretion of the proinflammatory chemokine interleukin-8 (IL-8).

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