Presentation Details
| Bitter Peptides Derived From Gastric Digestion of Sweet-Tasting Thaumatin Ameliorate H.pylori Induced Pro-Inflammatory IL-17A Release via Bitter Taste Receptor TAS2R16 Phil Richter1, 2, Karin Sebald2, Konrad Fischer3, Angelika Schnieke3, Malek Jlilati2, Verena Mittermeier-Kleßinger4, Veronika Somoza2, 5, 6. 1TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.2Leibniz Institute for Food Systems Biology at the Technical University of Munich, Freising, Germany.3Chair of Livestock Biotechnology, TUM School of Life Sciences, Technical University of Munich, Freising, Germany.4Chair of Food Chemistry and Molecular Sensory Science, Technical University of Munich, Freising, Germany.5Chair of Nutritional Systems Biology, TUM School of Life Sciences, Technical University of Munich, Freising, Germany.6Department of Physiological Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria |
Abstract
The plant Thaumatococcus daniellii, which is mainly native to Africa, contains the protein thaumatin, which tastes about 1600 times sweeter than sucrose and is used as a sugar substitute in foods to reduce their calorie content. Since in one of our previous studies, we demonstrated that bitter-tasting peptides released upon gastric digestion of non-bitter-tasting casein stimulate cellular proton secretion as a key mechanism of gastric acid formation, we hypothesized the sweet-tasting thaumatin to be cleaved into bitter-tasting peptides when subjected to an in vitro protocol of gastric digestion. The bitter peptides formed were tested for their ability to stimulate the proton secretion of immortalized human parietal cells (HGT‑1) and to reduce pro-inflammatory effects evoked by exposure to H. pylori via bitter taste receptors (TAS2Rs). For this purpose, thaumatin was digested using an established in vitro digestion approach, and the resulting peptides were identified via LC-ToF-MS. Subsequent quantification by LC-MS/MS was followed by validation of the formation of the peptides in pigs. The in silico predicted taste quality of the peptides was validated by sensory tests. Treatment of HGT-1 cells with the bitter peptides stimulated cellular proton secretion and reduced the H. pylori-evoked release of IL-17A by up to 89.7 ± 21.9% (p ≤ 0.01). To investigate a potential involvement of TAS2Rs, the stimulating effects of bitter peptides on proton secretion could be reduced using the TAS2R16 antagonist probenecid. Functional involvement of TAS2R16 in the H. pylori-evoked IL-17A release was demonstrated by means of specific siRNA. The results provide the molecular basis for bitter peptides generated upon gastric digestion to help reducing inflammatory processes, e.g. induced by H. pylori infection.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.