The ingestion of wheat gliadin (alcohol-soluble proteins, an integral part of wheat gluten) and related proteins induce, in genetically predisposed individuals, celiac disease (CD), which is characterized by immune-mediated impairment of the small intestinal mucosa. The lifelong omission of gluten and related grain proteins, i.e., a gluten-free diet (GFD), is at present the only therapy for CD. Although a GFD usually reduces CD symptoms, it does not entirely restore the small intestinal mucosa to a fully healthy state. Recently, the participation of microbial components in pathogenetic mechanisms of celiac disease was suggested. The present review provides information on infectious diseases associated with CD and the putative role of infections in CD development. Moreover, the involvement of the microbiota as a factor contributing to pathological changes in the intestine is discussed. Attention is paid to the mechanisms by which microbes and their components affect mucosal immunity, including tolerance to food antigens. Modulation of microbiota composition and function and the potential beneficial effects of probiotics in celiac disease are discussed.

• Klíčová slova
• celiac disease, gluten-free diet, immune response, infections, microbiota, parasites,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

In genetically predisposed individuals, ingestion of wheat gliadin provokes a T-cell-mediated enteropathy, celiac disease. Gliadin fragments were previously reported to induce phenotypic maturation and Th1 cytokine production by human dendritic cells (DCs) and to boost their capacity to stimulate allogeneic T cells. Here, we monitor the effects of gliadin on migratory capacities of DCs. Using transwell assays, we show that gliadin peptic digest stimulates migration of human DCs and their chemotactic responsiveness to the lymph node-homing chemokines CCL19 and CCL21. The gliadin-induced migration is accompanied by extensive alterations of the cytoskeletal organization, with dissolution of adhesion structures, podosomes, as well as up-regulation of the CC chemokine receptor (CCR) 7 on cell surface and induction of cyclooxygenase (COX)-2 enzyme that mediates prostaglandin E2 (PGE₂) production. Blocking experiments confirmed that gliadin-induced migration is independent of the TLR4 signalling. Moreover, we showed that the α-gliadin-derived 31-43 peptide is an active migration-inducing component of the digest. The migration promoted by gliadin fragments or the 31-43 peptide required activation of p38 mitogen-activated protein kinase (MAPK). As revealed using p38 MAPK inhibitor SB203580, this was responsible for DC cytoskeletal transition, CCR7 up-regulation and PGE₂ production in particular. Taken together, this study provides a new insight into pathogenic features of gliadin fragments by demonstrating their ability to promote DC migration, which is a prerequisite for efficient priming of naive T cells, contributing to celiac disease pathology.

• MeSH
• aktivace enzymů účinky léků   MeSH
• biologické modely MeSH
• chemokin CCL19 farmakologie   MeSH
• chemokin CCL21 farmakologie   MeSH
• chemotaxe účinky léků   MeSH
• cyklooxygenasa 2 metabolismus   MeSH
• cytoskelet účinky léků   metabolismus   MeSH
• dendritické buňky cytologie   účinky léků   enzymologie   MeSH
• dinoproston biosyntéza   MeSH
• gliadin farmakologie   MeSH
• lidé MeSH
• MAP kinasový signální systém účinky léků   MeSH
• mitogenem aktivované proteinkinasy p38 metabolismus   MeSH
• peptidové fragmenty farmakologie   MeSH
• receptory CCR7 metabolismus   MeSH
• upregulace účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• CCR7 protein, human MeSH Prohlížeč
• chemokin CCL19 MeSH
• chemokin CCL21 MeSH
• cyklooxygenasa 2 MeSH
• dinoproston MeSH
• gliadin MeSH
• mitogenem aktivované proteinkinasy p38 MeSH
• peptidové fragmenty MeSH
• PTGS2 protein, human MeSH Prohlížeč
• receptory CCR7 MeSH

Metagenomic approaches are currently being used to decipher the genome of the microbiota (microbiome), and, in parallel, functional studies are being performed to analyze the effects of the microbiota on the host. Gnotobiological methods are an indispensable tool for studying the consequences of bacterial colonization. Animals used as models of human diseases can be maintained in sterile conditions (isolators used for germ-free rearing) and specifically colonized with defined microbes (including non-cultivable commensal bacteria). The effects of the germ-free state or the effects of colonization on disease initiation and maintenance can be observed in these models. Using this approach we demonstrated direct involvement of components of the microbiota in chronic intestinal inflammation and development of colonic neoplasia (i.e., using models of human inflammatory bowel disease and colorectal carcinoma). In contrast, a protective effect of microbiota colonization was demonstrated for the development of autoimmune diabetes in non-obese diabetic (NOD) mice. Interestingly, the development of atherosclerosis in germ-free apolipoprotein E (ApoE)-deficient mice fed by a standard low-cholesterol diet is accelerated compared with conventionally reared animals. Mucosal induction of tolerance to allergen Bet v1 was not influenced by the presence or absence of microbiota. Identification of components of the microbiota and elucidation of the molecular mechanisms of their action in inducing pathological changes or exerting beneficial, disease-protective activities could aid in our ability to influence the composition of the microbiota and to find bacterial strains and components (e.g., probiotics and prebiotics) whose administration may aid in disease prevention and treatment.

• MeSH
• autoimunitní nemoci etiologie   mikrobiologie   MeSH
• gastrointestinální trakt mikrobiologie   MeSH
• gnotobiologické modely * MeSH
• imunita MeSH
• lidé MeSH
• metagenom imunologie   MeSH
• modely nemocí na zvířatech MeSH
• nádory etiologie   mikrobiologie   MeSH
• sliznice imunologie   MeSH
• zánět etiologie   mikrobiologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

BACKGROUND AND AIMS: Celiac disease (CD) is a chronic inflammatory disorder of the small intestine that is induced by dietary wheat gluten proteins (gliadins) in genetically predisposed individuals. The overgrowth of potentially pathogenic bacteria and infections has been suggested to contribute to CD pathogenesis. We aimed to study the effects of gliadin and various intestinal bacterial strains on mucosal barrier integrity, gliadin translocation, and cytokine production. METHODOLOGY/PRINCIPAL FINDINGS: Changes in gut mucosa were assessed in the intestinal loops of inbred Wistar-AVN rats that were reared under germ-free conditions in the presence of various intestinal bacteria (enterobacteria and bifidobacteria isolated from CD patients and healthy children, respectively) and CD-triggering agents (gliadin and IFN-γ) by histology, scanning electron microscopy, immunofluorescence, and a rat cytokine antibody array. Adhesion of the bacterial strains to the IEC-6 rat cell line was evaluated in vitro. Gliadin fragments alone or together with the proinflammatory cytokine interferon (IFN)-γ significantly decreased the number of goblet cells in the small intestine; this effect was more pronounced in the presence of Escherichia coli CBL2 and Shigella CBD8. Shigella CBD8 and IFN-γ induced the highest mucin secretion and greatest impairment in tight junctions and, consequently, translocation of gliadin fragments into the lamina propria. Shigella CBD8 and E. coli CBL2 strongly adhered to IEC-6 epithelial cells. The number of goblet cells in small intestine increased by the simultaneous incubation of Bifidobacterium bifidum IATA-ES2 with gliadin, IFN-γ and enterobacteria. B. bifidum IATA-ES2 also enhanced the production of chemotactic factors and inhibitors of metalloproteinases, which can contribute to gut mucosal protection. CONCLUSIONS: Our results suggest that the composition of the intestinal microbiota affects the permeability of the intestinal mucosa and, consequently, could be involved in the early stages of CD pathogenesis.

• MeSH
• Bacteria patogenita   MeSH
• bakteriální toxiny farmakologie   MeSH
• Bifidobacterium patogenita   MeSH
• celiakie etiologie   MeSH
• cytokiny biosyntéza   MeSH
• Enterobacteriaceae patogenita   MeSH
• gliadin farmakokinetika   farmakologie   MeSH
• gnotobiologické modely MeSH
• interakce hostitele a patogenu účinky léků   MeSH
• interferon gama farmakologie   MeSH
• krysa rodu Rattus MeSH
• permeabilita MeSH
• pohárkové buňky patologie   MeSH
• střeva mikrobiologie   patologie   MeSH
• střevní sliznice účinky léků   metabolismus   mikrobiologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální toxiny MeSH
• cytokiny MeSH
• gliadin MeSH
• interferon gama MeSH