Open AccessIntracellular Localization of Microbial Transglutaminase and Its Influence on the Transport of Gliadin in Enterocytes
Author(s) -
Stricker Sebastian,
Laffolie Jan,
Rudloff Silvia,
Komorowski Lars,
Zimmer KlausPeter
Publication year - 2019
Publication title -
journal of pediatric gastroenterology and nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.206
H-Index - 131
eISSN - 1536-4801
pISSN - 0277-2116
DOI - 10.1097/mpg.0000000000002171
Subject(s) - lamina propria , tissue transglutaminase , antigen , gliadin , endoplasmic reticulum , intracellular , antigen presentation , immune system , biology , immunology , microbiology and biotechnology , medicine , t cell , epithelium , biochemistry , enzyme , pathology , gluten
Objective: Celiac disease (CD) is a systemic inflammatory disorder, characterized by the destruction of duodenal epithelium. The CD8 + T cells involved are associated with cross‐presentation. In addition to other factors, the rising prevalence of CD might be induced by microbial transglutaminase (mTG) an enzyme frequently used in food production that shares enzymatic and antigenic properties of tissue transglutaminase (TG2), the autoantigen in CD. We hypothesized that mTG and gliadin are transported into the endoplasmic reticulum (ER), indicating cross‐presentation of both antigens. Methods: Apical incubation of duodenal biopsies from CD and control patients was performed with mTG alone or with mTG and simultaneously with Frazer's fraction. Evaluation was carried out by immunofluorescence and electron microscopy. Results: Approximately 6% to 9% of the intracellular mTG and gliadin were transported to the ER of enterocytes. RACE cells (Rapid uptake of Antigen into the Cytosol of Enterocytes) displayed an enhanced antigen uptake into a dilated ER. mTG strongly localized at the basolateral membrane and the lamina propria. Conclusions: mTG and gliadin are transported to the ER of enterocytes and to a greater extent to the ER of RACE cells, suggesting cross‐presentation of exogenous antigens. The strong localization of mTG at the basolateral membrane and the lamina propria may also indicate a potential antigenic interaction with cells of the immune system. Since mTG may not only been taken up with food stuffs but could also be released by bacteria within the intestinal microbiota, further investigations are needed regarding the role of mTG in CD pathogenesis.