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Dodero VI, Herrera MG. Oligomerization of 33-mer Gliadin Peptides: Supramolecular Assemblies in Celiac Disease. ChemMedChem 2025; 20:e202400789. [PMID: 39635969 DOI: 10.1002/cmdc.202400789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2024] [Revised: 12/04/2024] [Accepted: 12/05/2024] [Indexed: 12/07/2024]
Abstract
The 33-mer gliadin peptide and its deamidated derivative, known as 33-mer DGP, are proteolytically resistant peptides central to the pathomechanism of celiac disease (CeD), the autoimmune presentation of gluten-related disorders (GRD). Both peptides can form spontaneous oligomers in the nanomolar concentration, leading to the formation of nanostructures. In other protein-related diseases, oligomers and aggregates are central in their pathomechanism; therefore, it was hypothesized that the oligomerization of proteolytical-resistant 33-mer gliadin peptides could be an underrecognized disease trigger. This review focuses on the current understanding of 33-mer peptides and their oligomers in vitro and cellular experiments. We intend to give the necessary details that incentivize the chemistry community to get involved in the effort to understand the self-assembly of gliadin peptides and the role of their supramolecular structures in CeD and the other GRD. More research is needed to design effective and safe chemical and/or nutritional interventions beyond the gluten-free diet.
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Affiliation(s)
- Verónica I Dodero
- Department of Chemistry, Bielefeld University, Universitätsstr. 25, 33615, Bielefeld, Germany
| | - María G Herrera
- Molecular Cell Biology, Faculty of Medicine, Ruhr University Bochum, Universitätsstr. 150, 44801, Bochum, Germany
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Ebrahimzadegan R, Mirzaghaderi G. Variations in the composition and frequency of celiac disease epitopes among synthetic wheat lines. FRONTIERS IN PLANT SCIENCE 2025; 15:1517821. [PMID: 39931335 PMCID: PMC11807966 DOI: 10.3389/fpls.2024.1517821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2024] [Accepted: 12/31/2024] [Indexed: 02/13/2025]
Abstract
Bread wheat serves as an important staple crop in the human diet, largely because of the physicochemical properties of its dough and its protein content. Gluten is the main and complex component of wheat proteins. Despite the significant importance in breadmaking properties, wheat gluten contains some immunogenic peptides capable of triggering a T cell reaction in celiac disease (CD) patients, leading to inflammation in the small intestine. Among gluten proteins, α-gliadins are the most immunogenic components because they possess the primary T-cell stimulating epitopes (DQ2.5-Glia-α1, DQ2.5-Glia-α2, and DQ2.5-Glia-α3), which are primarily located on the D subgenome. Developing new wheat varieties by integrating the D subgenome from various sources is not only useful for introducing low immunogenic gluten, but it can also circumvent the challenging policies arising from the manipulation of wheat genome through transgenic approaches. Here, we performed RNA amplicon sequencing of the most toxic region of alpha-gliadins to analyze the content and composition of CD-related alpha-gliadin epitopes across eight synthetic wheat lines developed from crosses between durum wheat and different Aegilops species containing the D-genome (Ae. tauschii, Ae. crassa, and Ae. ventricosa). By searching the previously identified 121 epitopes and those with one mismatch in our amplicons, we found 54 different α-gliadins epitopes across our genotypes, four of which were new variants. The canonical epitopes were present in all lines, although their expression patterns varied. The occurrence of DQ2.5-Glia-α1a and DQ2.5-Glia-α3 was higher than that of DQ2.5-Glia-α2 and DQ2.5-Glia-α1b across all genotypes. Since a higher quantity of toxic alpha-gliadin epitopes is associated with increased immunogenicity in individuals susceptible to celiac disease, we measured the frequency of the most toxic alpha-gliadin epitopes among different synthetic lines to estimate the overall immunogenic load of our lines. Generally, the immunogenic load of lines with the D-genome originating from Ae. crassa was much lower than those with the D-genome from Ae. tauschii. In this way, the Ae. tauschii derived lines 5 and 6 contained higher levels of toxic alpha-gliadin epitopes, while lines 3, 4, and 7 (derived from Ae. crassa) contained the lowest levels of toxic peptides. We conclude that replacing the bread wheat D-genome with that of the Ae. crassa may help lower the gluten immunogenicity in the deriving synthetic wheat lines.
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Affiliation(s)
- Rahman Ebrahimzadegan
- Department of Plant Production and Genetics, Faculty of Agriculture, University of
Kurdistan, Sanandaj, Iran
| | - Ghader Mirzaghaderi
- Department of Plant Production and Genetics, Faculty of Agriculture, University of
Kurdistan, Sanandaj, Iran
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Marín-Sanz M, Barro F, Sánchez-León S. Unraveling the celiac disease-related immunogenic complexes in a set of wheat and tritordeum genotypes: implications for low-gluten precision breeding in cereal crops. FRONTIERS IN PLANT SCIENCE 2023; 14:1171882. [PMID: 37251754 PMCID: PMC10210591 DOI: 10.3389/fpls.2023.1171882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/06/2023] [Indexed: 05/31/2023]
Abstract
The development of low-gluten immunogenic cereal varieties is a suitable way to fight the increment of pathologies associated with the consumption of cereals. Although RNAi and CRISPR/Cas technologies were effective in providing low-gluten wheat, the regulatory framework, particularly in the European Union, is an obstacle to the short- or medium-term implementation of such lines. In the present work, we carried out a high throughput amplicon sequencing of two highly immunogenic complexes of wheat gliadins in a set of bread and durum wheat, and tritordeum genotypes. Bread wheat genotypes harboring the 1BL/1RS translocation were included in the analysis and their amplicons successfully identified. The number of CD epitopes and their abundances were determined in the alpha- and gamma-gliadin amplicons, including 40k-γ-secalin ones. Bread wheat genotypes not containing the 1BL/1RS translocation showed a higher average number of both alpha- and gamma-gliadin epitopes than those containing such translocation. Interestingly, alpha-gliadin amplicons not containing CD epitopes accounted for the highest abundance (around 53%), and the alpha- and gamma-gliadin amplicons with the highest number of epitopes were present in the D-subgenome. The durum wheat and tritordeum genotypes showed the lowest number of alpha- and gamma-gliadin CD epitopes. Our results allow progress in unraveling the immunogenic complexes of alpha- and gamma-gliadins and can contribute to the development of low-immunogenic varieties within precision breeding programs, by crossing or by CRISPR/Cas gene editing.
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Zeibig F, Kilian B, Frei M. The grain quality of wheat wild relatives in the evolutionary context. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2022; 135:4029-4048. [PMID: 34919152 PMCID: PMC9729140 DOI: 10.1007/s00122-021-04013-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/06/2021] [Indexed: 05/17/2023]
Abstract
KEY MESSAGE We evaluated the potential of wheat wild relatives for the improvement in grain quality characteristics including micronutrients (Fe, Zn) and gluten and identified diploid wheats and the timopheevii lineage as the most promising resources. Domestication enabled the advancement of civilization through modification of plants according to human requirements. Continuous selection and cultivation of domesticated plants induced genetic bottlenecks. However, ancient diversity has been conserved in crop wild relatives. Wheat (Triticum aestivum L.; Triticum durum Desf.) is one of the most important staple foods and was among the first domesticated crop species. Its evolutionary diversity includes diploid, tetraploid and hexaploid species from the Triticum and Aegilops taxa and different genomes, generating an AA, BBAA/GGAA and BBAADD/GGAAAmAm genepool, respectively. Breeding and improvement in wheat altered its grain quality. In this review, we identified evolutionary patterns and the potential of wheat wild relatives for quality improvement regarding the micronutrients Iron (Fe) and Zinc (Zn), the gluten storage proteins α-gliadins and high molecular weight glutenin subunits (HMW-GS), and the secondary metabolite phenolics. Generally, the timopheevii lineage has been neglected to date regarding grain quality studies. Thus, the timopheevii lineage should be subject to grain quality research to explore the full diversity of the wheat gene pool.
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Affiliation(s)
- Frederike Zeibig
- Department of Agronomy and Crop Physiology, Institute of Agronomy and Plant Breeding I, Justus-Liebig-University, 35392, Giessen, Germany
| | | | - Michael Frei
- Department of Agronomy and Crop Physiology, Institute of Agronomy and Plant Breeding I, Justus-Liebig-University, 35392, Giessen, Germany.
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Halstead-Nussloch G, Tanaka T, Copetti D, Paape T, Kobayashi F, Hatakeyama M, Kanamori H, Wu J, Mascher M, Kawaura K, Shimizu KK, Handa H. Multiple Wheat Genomes Reveal Novel Gli-2 Sublocus Location and Variation of Celiac Disease Epitopes in Duplicated α-Gliadin Genes. FRONTIERS IN PLANT SCIENCE 2021; 12:715985. [PMID: 34539709 PMCID: PMC8446623 DOI: 10.3389/fpls.2021.715985] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/12/2021] [Indexed: 05/28/2023]
Abstract
The seed protein α-gliadin is a major component of wheat flour and causes gluten-related diseases. However, due to the complexity of this multigene family with a genome structure composed of dozens of copies derived from tandem and genome duplications, little was known about the variation between accessions, and thus little effort has been made to explicitly target α-gliadin for bread wheat breeding. Here, we analyzed genomic variation in α-gliadins across 11 recently published chromosome-scale assemblies of hexaploid wheat, with validation using long-read data. We unexpectedly found that the Gli-B2 locus is not a single contiguous locus but is composed of two subloci, suggesting the possibility of recombination between the two during breeding. We confirmed that the number of immunogenic epitopes among 11 accessions varied. The D subgenome of a European spelt line also contained epitopes, in agreement with its hybridization history. Evolutionary analysis identified amino acid sites under diversifying selection, suggesting their functional importance. The analysis opens the way for improved grain quality and safety through wheat breeding.
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Affiliation(s)
- Gwyneth Halstead-Nussloch
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Tsuyoshi Tanaka
- Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba, Japan
- Research Center for Advanced Analysis, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Dario Copetti
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Molecular Plant Breeding, Institute of Agricultural Sciences, ETH Zürich, Zurich, Switzerland
| | - Timothy Paape
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Brookhaven National Laboratory, Upton, NY, United States
| | - Fuminori Kobayashi
- Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Masaomi Hatakeyama
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Functional Genomics Center Zurich, Zurich, Switzerland
| | - Hiroyuki Kanamori
- Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Jianzhong Wu
- Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Martin Mascher
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Kanako Kawaura
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Japan
| | - Kentaro K. Shimizu
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Japan
| | - Hirokazu Handa
- Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba, Japan
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
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Genome editing of polyploid crops: prospects, achievements and bottlenecks. Transgenic Res 2021; 30:337-351. [PMID: 33846956 PMCID: PMC8316217 DOI: 10.1007/s11248-021-00251-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 03/29/2021] [Indexed: 02/07/2023]
Abstract
Plant breeding aims to develop improved crop varieties. Many crops have a polyploid and often highly heterozygous genome, which may make breeding of polyploid crops a real challenge. The efficiency of traditional breeding based on crossing and selection has been improved by using marker-assisted selection (MAS), and MAS is also being applied in polyploid crops, which helps e.g. for introgression breeding. However, methods such as random mutation breeding are difficult to apply in polyploid crops because there are multiple homoeologous copies (alleles) of each gene. Genome editing technology has revolutionized mutagenesis as it enables precisely selecting targets. The genome editing tool CRISPR/Cas is especially valuable for targeted mutagenesis in polyploids, as all alleles and/or copies of a gene can be targeted at once. Even multiple genes, each with multiple alleles, may be targeted simultaneously. In addition to targeted mutagenesis, targeted replacement of undesirable alleles by desired ones may become a promising application of genome editing for the improvement of polyploid crops, in the near future. Several examples of the application of genome editing for targeted mutagenesis are described here for a range of polyploid crops, and achievements and bottlenecks are highlighted.
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