Tracking gluten immunoreactive peptides from the grain to the gut and beyond

Project Information

GLUTENOMICS

Grant agreement ID: 101040437

DOI

10.3030/101040437

EC signature date 19 April 2022

Start date 1 September 2022

End date 31 August 2027

Funded under

• European Research Council (ERC)

Total cost

€ 1 499 988,00

EU contribution

€ 1 499 988,00

Coordinated by

LEIBNIZ-INSTITUT FUER LEBENSMITTEL-SYSTEMBIOLOGIE AN DER TECHNISCHEN UNIVERSITAET MUENCHEN
Germany

Periodic Reporting for period 1 - GLUTENOMICS (Tracking gluten immunoreactive peptides from the grain to the gut and beyond)

Reporting period: 2022-09-01 to 2025-02-28

Summary of the context and overall objectives of the project

Wheat is one of the pillars for nutrition security worldwide, but the prevalence of wheat-related disorders (WRD) is increasing. Taken together, coeliac disease, non-coeliac gluten sensitivity and wheat food allergy may affect up to 10% of European individuals. The causes for this increase are still unknown, but involve the intricate interaction of proteolytically resistant gluten immunoreactive peptides (GIP) from wheat, rye and barley, the human immune system and yet unknown adjuvants. Total GIP can be detected by immunoassays in human plasma, urine and faeces (biosamples) after gluten consumption, but the precise molecular structures have not been clarified so far, because specific analytical methods are missing.
The project GLUTENOMICS aims to elucidate the molecular structures of GIP in human biosamples and analyse factors determining their identities and quantities. The central hypothesis is that gluten structure and content determine its digestibility which, in turn, leads to different GIP profiles in biosamples from healthy individuals and WRD patients. The findings will pave the way to tailor grain-based foods towards better tolerability to prevent the initial onset of WRD.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

We investigated the presence of peptides with coeliac disease (CD)-active epitope in the five wheat species common wheat, spelt, durum wheat, emmer, and einkorn. In total, 494 peptides with CD-active epitope were identified. Considering the average of the eight cultivars of each species, spelt contained the highest number of different peptides with CD-active epitope (193 ± 12, mean ± SD). Einkorn showed the smallest variability of peptides (63 ± 4) but higher amounts of certain peptides compared to the other species.
A comprehensive database with proteins from wheat, rye, and barley containing known immunoreactive epitopes in the context of WRD and similar proteins not yet known to be immunoreactive for the in silico prediction of GIP was created. To compare gluten digestibility and the GIP profile of different flours, bread, and cakes after static in vitro digestion, the workflow was established from the food to discovery proteomics measurement and data analysis by optimizing all relevant steps including peptide clean-up, drying, dissolving and diluting the peptides, the proteomics measurement, and data evaluation. Following the successful optimization of the workflow for static in vitro digestion, different foods are now being prepared and studied using discovery proteomics.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The accurate quantitation of gluten in supposedly gluten-free products still represents a major challenge, especially for rye and barley, because gluten contamination from these two grains is usually either over- or underestimated using current analytical methods that are calibrated to wheat. We addressed the current lack of appropriate reference materials and, for the first time, developed reference materials for rye and barley that will significantly increase food safety for celiac disease patients. In addition to the availability of the rye and barley flours mixtures to be used as reference materials, we also produced prolamin, glutelin and gluten isolates which have excellent storage properties.

Number of peptides with CD-active epitope that are unique or shared