ABSTRACT
BACKGROUND: The significance of the presence of anti-gliadin antibodies in patients affected by celiac disease is still unclear. It is hypothesized that gliadin deamidation, catalysed by transglutaminase, plays a role in favoring the antigen presentation. AIM: To determine the immunoreactivity of anti-gliadin antibodies from untreated celiac patients to transglutaminase deamidated gliadins. MATERIALS AND METHODS: Gliadins from wheat flour underwent enzymatic digestion and were deamidated or cysteamine-transamidated by transglutaminase. Immunoreactivity of anti-gliadin antibodies from untreated adult celiac patients sera was evaluated by means of a competitive enzyme-linked immunosorbent assay (ELISA) method. RESULTS: Gliadin deamidation increased antibodies immunoreactivity from 25% to 50% while cysteamine incorporation into the gliadin peptides resulted in an immunoreactivity decrease. CONCLUSIONS: Increased immunoreactivity of transglutaminase deamidated gliadins tested with anti-gliadin antibodies from untreated adult celiac patients supports the hypothesis of a pivotal role of gliadin deamidation in the pathomechanism of celiac disease.
Subject(s)
Antibodies/immunology , Celiac Disease/immunology , Gliadin/immunology , Gliadin/metabolism , Transglutaminases/pharmacology , Adult , Antibodies/blood , Celiac Disease/etiology , Celiac Disease/metabolism , Cysteamine/metabolism , Deamination/drug effects , Enzyme-Linked Immunosorbent Assay , Female , Gliadin/drug effects , Humans , MaleABSTRACT
The effects of chemical (acid-heating treatment) and enzymatic (microbial transglutaminase, TGase) modification (deamidation) of gluten proteins on their physicochemical and celiac disease-related properties were studied. Ammonia release, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and sample solubility analyses were employed to check the extent of gluten modification. Among different treatments achieved, the acid-heating treatment performed at 90 degrees C for 3 h induced gluten deamidation, paralleling an increase of gluten solubility without relevant proteolysis. Changes in the immunoreactivity of celiac IgA anti-gliadin antibodies (AGAs) to modified gluten proteins were detected by using a competitive indirect enzyme-linked immunosorbent assay method. Chemical deamidation by acid-heating treatment of gluten lowered IgA-AGA immunoreactivity. IgA-AGA immunoreactivity to gliadins was increased when they were submitted to TGase-catalyzed deamidation. The acid-heating treatment of gluten reduced its cytotoxic activity on human colon adenocarcinoma LoVo cell line. These results showed that chemical deamidation of gluten may be envisaged as a way to lower the potential risk for celiac people due to widespread use of gluten as a food additive.
Subject(s)
Celiac Disease/etiology , Glutens/chemistry , Glutens/metabolism , Cell Line, Tumor , Chemical Phenomena , Chemistry, Physical , Colonic Neoplasms/pathology , Gliadin/immunology , Glutens/immunology , Hot Temperature , Humans , Hydrogen-Ion Concentration , Immunoglobulin A/immunology , Transglutaminases/metabolismABSTRACT
AIM: To evaluate the effects of gliadin on the oxidative environment in the "in vivo-like" model of a three-dimensional cell culture system. METHODS: LoVo cell line (intestinal adenocarcinoma) multicellular spheroids were treated with digested gliadin (with albumin used as a control). Spheroid volumes, cell viability and morphology, lactate dehydrogenase (LDH) release, content of reduced glutathione (GSH) and activity of GSH-related enzymes were examined. The data were statistically analyzed using the Student's t-test. was considered statistically significant. RESULTS: Gliadin reduced cell viability (from 20% to 60%) and led to morphological alterations characterized by apoptotic findings and cytoskeletal injuries. LDH activity increased. The content of GSH reduced (-20% vs controls), and activity of GSH-related enzymes was significantly inhibited. CONCLUSION: Gliadin treatment induces an imbalance in the antioxidative mechanism of cells cultured by the three-dimensional technique. This alteration may explain the cell damage directly caused by gliadin and the subsequent morphological abnormalities.