Oral Consumption of Bread from an RNAi Wheat Line with Strongly Silenced Gliadins Elicits No Immunogenic Response in a Pilot Study with Celiac Disease Patients

Abstract

Celiac disease (CD) is a genetically predisposed, T cell-mediated and autoimmune-like disorder caused by dietary exposure to the storage proteins of wheat and related cereals. A gluten-free diet (GFD) is the only treatment available for CD. The celiac immune response mediated by CD4+ T-cells can be assessed with a short-term oral gluten challenge. This study aimed to determine whether the consumption of bread made using flour from a low-gluten RNAi wheat line (named E82) can activate the immune response in DQ2.5-positive patients with CD after a blind crossover challenge. The experimental protocol included assessing IFN-γ production by peripheral blood mononuclear cells (PBMCs), evaluating gastrointestinal symptoms, and measuring gluten immunogenic peptides (GIP) in stool samples. The response of PBMCs was not significant to gliadin and the 33-mer peptide after E82 bread consumption. In contrast, PBMCs reacted significantly to Standard bread. This lack of immune response is correlated with the fact that, after E82 bread consumption, stool samples from patients with CD showed very low levels of GIP, and the symptoms were comparable to those of the GFD. This pilot study provides evidence that bread from RNAi E82 flour does not elicit an immune response after a short-term oral challenge and could help manage GFD in patients with CD.

Targeting Induced Local Lesions in the Wheat DEMETER and DRE2 Genes, Responsible for Transcriptional Derepression of Wheat Gluten Proteins in the Developing Endosperm

“…Therefore, to some extent, these experiments have answered the question about the utility of low-gluten and/or celiac-safe wheat genotypes in baking bread/cookies. Also, in a recent study, Guzmán-López et al ( 83 ) showed that the bread derived from a low-gluten RNAi wheat line did not elicit the immune response in the DQ2.5-positive celiac patients, much like the gluten-free diet, under a short-term oral challenge. However, despite the fact that the reduced gluten mutants maintain reasonable end-use properties and exhibit reduced content of immunogenic proteins, inducing mutations in the DME and DRE2 genes is an unviable approach due to the role of these genes in pollen viability and germination.…”

RNAi silencing of wheat gliadins alters the network of transcription factors that regulate the synthesis of seed storage proteins toward maintaining grain protein levels

“…The down-regulation of wheat gliadins by RNAi provided lines with a reduction of up to 98% of gluten in the grain ( Gil-Humanes et al, 2010 ). The most outstanding line, named E82, showed the lowest amount of CD immunogenic epitopes ( Sánchez-León et al, 2019 ), and elicited no immunogenic response in celiac disease patients after the oral consumption of E82 bread ( Guzmán-López et al, 2021 ). Moreover, this line presents sensory properties comparable to that of the WT flour, suggesting that gliadins could not play a relevant role in texture, aroma, flavor and appearance as much as other grain components ( Cho and Peterson, 2010 ; Gil-Humanes et al, 2014a ).…”

“…However, the depletion of gliadin proteins affects the bread-making quality depending on the protein fraction being silenced ( Gil-Humanes et al, 2012 , 2014b ). One wheat line denoted as E82 highlights among all RNAi lines produced, with a reduction of 98% of gluten content ( Gil-Humanes et al, 2010 ), and the bread made using flour from this line was tolerated by NCWS patients ( Haro et al, 2018 ), and did not elicit an immunogenic response in a blind randomized crossover gluten challenge with CD patients ( Guzmán-López et al, 2021 ).…”

New Developments in Celiac Disease Treatment

“…One example is the E82 wheat line produced by RNAi technology that blocks relevant gliadin genes [ 57 ]. A pilot study with 21 CD patients eating E82 wheat did show decreased interferon-γ (INF-γ) production in peripheral blood mononuclear cells and a very low level of gluten immunogenic peptides (GIP) in stool samples from those patients, suggesting low exposure to immunogenic epitopes [ 58 ].…”