epidermal-growth-factor and Celiac-Disease

Celiac disease (CD) is a frequent inflammatory intestinal disease, with a genetic background, caused by gliadin-containing food. Undigested gliadin peptides induce innate and adaptive T cell-mediated immune responses. The major mediator of the stress and innate immune response to gliadin peptides (i.e., peptide 31-43, P31-43) is the cytokine interleukin-15 (IL-15). The role of epithelial growth factor (EGF) as a mediator of enterocyte proliferation and the innate immune response has been described. In this paper, we review the most recent literature on the mechanisms responsible for triggering the up-regulation of these mediators in CD by gliadin peptides. We will discuss the role of P31-43 in enterocyte proliferation, structural changes and the innate immune response in CD mucosa in cooperation with EGF and IL-15, and the mechanism of up-regulation of these mediators related to vesicular trafficking. We will also review the literature that focuses on constitutive alterations of the structure, signalling/proliferation and stress/innate immunity pathways of CD cells. Finally, we will discuss how these pathways can be triggered by gliadin peptide P31-43 in controls, mimicking the celiac cellular phenotype.

Topics: Animals; Celiac Disease; Cell Proliferation; Enterocytes; Epidermal Growth Factor; ErbB Receptors; Gliadin; Humans; Immunity, Innate; Interleukin-15; Intestinal Mucosa; Intestine, Small; Peptide Fragments

On ingestion of gliadin, the major protein component of wheat and other cereals, the celiac intestine is characterized by the proliferation of crypt enterocytes with an inversion of the differentiation/proliferation program. Gliadins and A-gliadin peptide P31-43, in particular, act as growth factors for crypt enterocytes in patients with celiac disease (CD). The effects of gliadin on crypt enterocyte proliferation and activation of innate immunity are mediated by epidermal growth factors (EGFs) and innate immunity mediators [interleukin 15 (IL15)].. The aim of this study was to determine the molecular basis of proliferation and innate immune response to gliadin peptides in enterocytes.. The CaCo-2 cell line was used to study EGF-, IL15-, and P31-43-induced proliferation. Silencing messenger RNAs and blocking EGF receptor and IL15 antibodies have been used to study proliferation in CaCo-2 cells and intestinal biopsy samples from patients with CD and control subjects.. In the CaCo-2 cell model, IL15 and EGF cooperated to induce proliferation in intestinal epithelial cells at both the transcriptional and posttranscriptional levels, and the respective receptors interacted to activate each other's signaling. In addition, the effects of the P31-43 peptide on CaCo-2 cell proliferation and downstream signaling were mediated by cooperation between EGF and IL15. The increased crypt enterocyte proliferation in intestinal biopsy samples from patients with CD was reduced by EGF receptor and IL15 blocking antibodies only when used in combination.. EGF receptor/IL15R-α cooperation regulates intestinal epithelial cell proliferation induced by EGF, IL15, and the gliadin peptide P31-43. Increased proliferation of crypt enterocytes in the intestine of CD patients is mediated by EGF/IL15 cooperation.

Topics: Antibodies; Caco-2 Cells; Celiac Disease; Cell Proliferation; Cells, Cultured; Enterocytes; Epidermal Growth Factor; ErbB Receptors; Gene Expression Regulation; Gliadin; Humans; Immunity, Innate; Interleukin-15; Interleukin-15 Receptor alpha Subunit; Peptide Fragments; Phosphorylation; RNA, Small Interfering; Signal Transduction; Transfection

Celiac disease (CD) occurs frequently, and is caused by ingestion of prolamins from cereals in subjects with a genetic predisposition. The small intestinal damage depends on an intestinal stress/innate immune response to certain gliadin peptides (e.g., A-gliadin P31-43) in association with an adaptive immune response to other gliadin peptides (e.g., A-gliadin P57-68). Gliadin and peptide P31-43 affect epithelial growth factor receptor (EGFR) signaling and CD enterocyte proliferation. The reason why the stress/innate immune and proliferative responses to certain gliadin peptides are present in CD and not in control intestine is so far unknown. The aim of this work is to investigate if, in CD, a constitutive alteration of enterocyte proliferation and signaling exists that may represent a predisposing condition to the damaging effects of gliadin. Immunofluorescence and immunohistochemistry were used to study signaling in CD fibroblasts and intestinal biopsies. Western blot (WB) analysis, immunoprecipitation, and quantitative PCR were also used. We found in CD enterocytes enhancement of both proliferation and Epidermal Growth Factor Receptor (EGFR)/ligand system. In CD enterocytes and fibroblasts we found increase of the phosphorylated downstream signaling molecule Extracellular Signal Regulated Kinase (ERK); block of the ERK activation normalizes enterocytes proliferation in CD mucosa. In conclusion the same pathway, which gliadin and gliadin peptide P31-43 can interfere with, is constitutively altered in CD cells. This observation potentially explains the specificity of the damaging effects of certain gliadin peptides on CD intestine.

Topics: Adolescent; Biopsy; Celiac Disease; Cell Proliferation; Child; Child, Preschool; Enterocytes; Epidermal Growth Factor; ErbB Receptors; Extracellular Signal-Regulated MAP Kinases; Humans; Infant; Intestinal Mucosa; Phosphorylation; Signal Transduction

Gliadins, a family of wheat proteins, are central to the pathogenesis of celiac disease (CD). In addition to 'immunogenic' effects, gliadin directly affects cultured cells and intestine preparations, and produces damage in vivo, via a separate 'toxic' peptide, such as A-gliadin p31-43 (P31-43).. Understanding the molecular mechanisms underlying direct non T-cell mediated effects of gliadin peptides, and assessing their potential role in promoting CD.. Gliadin effects were tested on a number of cell lines and on cultured mucosa samples by evaluating cytoskeleton rearrangements, endocytosis, proliferation and apoptosis. Standard biochemical methods were used to assess prolonged epidermal growth factor receptor (EGFR) activation.. Crude gliadin peptic-tryptic peptides (PTG], or P31-43 alone, fully reproduce the effects of epidermal growth factor (EGF] on actin cytosketon, cell cycle and cell proliferation of various cell lines. Inhibitor studies demonstrate the role of EGFR in the early response to gliadin exposure, pointing to activation of the EGFR pathway. Peptide P31-43 is not similar to any EGFR ligand, but can delay inactivation of the EGFR interfering with its endocytosis. Gliadin-induced delay of EGFR endocytosis in cultured intestinal biopsies, together with S-phase entry of epithelial intestinal cells, confirm a role for EGFR activation in CD.. The ability of gliadin peptides to delay EGFR inactivation through interference with the endocytic pathway suggests a model where gliadin fragments amplify the effects of trace amounts of EGF, and possibly of other growth factors, by prolonging receptor activation. The results, using cultures of coeliac intestinal biopsies, highlight the role of the EGF pathway in establishing and maintaining the typical atrophic and proliferative alterations of the small intestine in CD.

Topics: Actins; Apoptosis; Caco-2 Cells; Celiac Disease; Cell Cycle; Cell Line; Cell Proliferation; Cytoskeleton; Endocytosis; Epidermal Growth Factor; ErbB Receptors; Gliadin; Humans; Intestinal Mucosa; Ligands; Organ Culture Techniques

A protective effect of breast-feeding against the development of celiac disease has been described, but the nature and effects of the actual milk components have not been established. Epidermal growth factor (EGF), a milk cytokine affecting the proliferation and differentiation of mucosal epithelial cells, was studied as to its potential protective effect on the damage of intestinal mucosa by gliadin in a model system.. Enteropathy was induced by gliadin in inbred AVN strain rat pups delivered by cesarean section, breast-fed, or hand-fed a milk formula. All experimental groups were treated with interferon-gamma (1,000 U per animal, administered intraperitoneally) after birth. Gliadin (0.5 and 3 mg) was intragastrically administered to the pups on days 0 and 3, and a 30-mg challenge dose was given on day 20 (24 hours before the termination of the experiment). One group of artificially fed pups received EGF (100 ng/ml) continuously in the diet.. Gliadin- and interferon-gamma-treated formula-fed rat pups showed villus atrophy, increase of inflammatory cells, including CD4+ T lymphocytes in the lamina propria, and damage to epithelial tight junctions and the enterocyte brush border. Morphometrically, the villus height was significantly less than in other groups. Recombinant EGF was markedly increased in the epithelial cells of injured jejunum. The intestinal mucosa of gliadin- and interferon-gamma-treated pups kept on a EGF-supplemented artificial diet resembled that of breast-fed pups.. Pathologic changes in jejunal mucosa (villus atrophy and inflammation) resembling gliadin-induced atrophy appeared on administration of interferon-gamma and gliadin to rat pups fed an artificial milk diet immediately after birth. Addition of EGF to the diet protected the rats against pathologic mucosal changes.

Topics: Animals; Animals, Newborn; Animals, Suckling; Body Weight; Celiac Disease; Disease Models, Animal; Epidermal Growth Factor; Gliadin; Jejunum; Microscopy, Electron, Scanning; Nutritional Support; Rats; Rats, Inbred Strains; Time Factors

Many growth factor receptors including the epidermal growth factor receptor function through tyrosine kinase activity. The aim of this study was to examine the constitutive level of tyrosine phosphorylation in the normal duodenum and in the hyperproliferative coeliac duodenum. A flow cytometric assay was devised using monoclonal antibody to phosphorylated (but not native) tyrosine residues to determine the levels of tyrosine phosphorylation in both CD3 positive intraepithelial lymphocytes and CD3 negative epithelial cells obtained by EDTA treatment of endoscopically obtained duodenal biopsy specimens. In addition, immunohistochemistry was performed on 18 formalin fixed coeliac duodenal biopsy specimens and eight control specimens. Tyrosine phosphorylation could be detected by flow cytometry on duodenal enterocytes and this expression was up regulated by pretreatment with epidermal growth factor. Tyrosine phosphorylation decreased with progression from the villus to the crypt, however, and was virtually undetectable on crypt enterocytes. Immunohistochemistry of the coeliac duodenum showed virtually absent tyrosine phosphorylation in the crypt. Increased tyrosine phosphorylation was detected in the infiltrating T cells. In conclusion, tyrosine phosphorylation in the duodenum is confined to the non-proliferative villous epithelium and is virtually undetectable in the proliferative crypt compartment. These findings suggest that tyrosine kinase activity is not a significant factor in the regulation of crypt cell proliferation in the human duodenum either in normal subjects or in coeliac disease patients.

Topics: CD3 Complex; Celiac Disease; Duodenum; Edetic Acid; Epidermal Growth Factor; Flow Cytometry; Humans; Immunoenzyme Techniques; Phosphorylation; Phosphotyrosine; Tyrosine