Translational Chemistry Meets Gluten-Related Disorders (original) (raw)
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Nutrients, 2016
Theterm gluten intolerance may refer to three types of human disorders: autoimmune celiac disease (CD), allergy to wheat and non-celiac gluten sensitivity (NCGS). Gluten is a mixture of prolamin proteins present mostly in wheat, but also in barley, rye and oat. Gluten can be subdivided into three major groups: S-rich, S-poor and high molecular weight proteins. Prolamins within the groups possess similar structures and properties. All gluten proteins are evolutionarily connected and share the same ancestral origin. Gluten proteins are highly resistant to hydrolysis mediated by proteases of the human gastrointestinal tract. It results in emergence of pathogenic peptides, which cause CD and allergy in genetically predisposed people. There is a hierarchy of peptide toxicity and peptide recognition by T cells. Nowadays, there are several ways to detoxify gluten peptides: the most common is gluten-free diet (GFD), which has proved its effectiveness; prevention programs, enzymatic therapy, correction of gluten pathogenicity pathways and genetically modified grains with reduced immunotoxicity. A deep understanding of gluten intolerance underlying mechanisms and detailed knowledge of gluten properties may lead to the emergence of novel effective approaches for treatment of gluten-related disorders.
A comprehensive review of biochemical, functional, and dietary implications of Gluten
In wheat grains, gluten serves as a major storage protein comprising a mixture of many related proteins, i.e., gliadin and glutenin. This class of proteins includes storage class proteins such as secalin (rye), hordein (barley), and avenins (oats). The present discussion will therefore address the biochemical and functional features of gluten duly examining their structures, rich sources, and evidence-based dietary implications. This study is based on literature from food science and nutrition journals. The network composition of gluten protein varies depending on genotype, growing conditions, or processing methods resulting in different components and sizes. The complicated structure and interactions contribute to the exclusive characteristics of gluten, thus determining the quality of dough for bread making among other baked products. Due to its heat stability, gluten serves as a binder and is often included as an additive in processed sort of foods to enhance texture, moisture holding, and flavour adding. Gliadin is a constituent of gluten that has peptide strings that are not easily digested in the digestive system comprising of the stomach, pancreas, and intestines. It is estimated that the average daily intake of gluten by individuals living on Western diets ranges between 5 to 20 g, and its consumption has been linked to several conditions. However, grains containing gluten like wheat, rye, barley, and oats will continue to be important food sources. To sum up, gluten is one of the most intricate protein networks that have critical implications for dough's rheological attributes.
Gluten proteins 2009. Proceedings of the 10th International Gluten workshop
2009
The processing properties of wheat flour are largely determined by the structures and interactions of the grain storage proteins, or gluten proteins, whose synthesis, folding and deposition take place within the endomembrane system of the plant cell. The determination of the precise mechanisms and pathways of trafficking and accumulation of these classes of storage proteins, however, has been limited in the past by difficulty in developing monospecific antibodies. We have overcome this limitation by producing transgenic wheat lines expressing C-terminal epitope-tagged gluten proteins which can be identified in the cells of the developing grain using highly specific commercial antibodies. Immunolocalisation studies carried out on developing grains from these transgenic lines showed differential patterns of deposition for the main sub-classes of gluten protein, with HMW subunits being particularly abundant in the inner layer of the endosperm and less abundant in the subaleurone layer, which instead is rich in gliadins and LMW glutenin subunits. Furthermore, our studies suggest that segregation of gluten proteins occurs both between and within protein bodies. The specific distributions of gluten proteins within the endosperm and their segregation during deposition may affect the subunit composition and the assembly of the glutenin polymers and, consequently, have an impact on grain quality.
Gluten proteins play a key role in determining the unique baking quality of wheat by conferring water absorption capacity, cohesivity, viscosity and elasticity on dough. Gluten proteins can be divided into two main fractions according to their solubility in aqueous alcohols: the soluble gliadins and the insoluble glutenins. Both fractions consist of numerous, partially closely related protein components characterized by high glutamine and proline contents. Gliadins are mainly monomeric proteins with molecular weights around 28,000-55,000 and can be classified according to their different primary structures into the alpha/beta-, gamma-and omega-type. Disulphide bonds are either absent or present as intrachain crosslink. The glutenin fraction comprises aggregated proteins linked by interchain disulphide bonds. After reduction of disulphide bonds, the resulting glutenin subunits show a solubility in aqueous alcohols similar to gliadins. Based on primary structure, glutenin subunits have been divided into the highmolecular-weight (HMW) subunits (MW=67,000-88,000) and low-molecular-weight (LMW) subunits (MW=32,000-35,000). Each gluten protein type consists of two or three different structural domains; one of them contains unique repetitive sequences rich in glutamine and proline. These domain and specific structures cause bad effects on living being's body. When gluten reaches the digestive tract and is exposed to the cells of the immune system, they mistakenly recognize it as a foreign invader, like a bacteria. In certain people who are sensitive to gluten, this causes the immune system to mount an attack against it. In celiac disease (the most severe form of gluten sensitivity), the immune system attacks the gluten proteins, but it also attacks an enzyme in the cells of the digestive tract called tissue transglutaminase. Therefore, attacks both the gluten as well as the intestinal wall itself. For this reason, celiac disease is classified as an autoimmune disease. The immune reaction can cause degeneration of the intestinal wall, which leads to nutrient deficiencies, various digestive issues, anemia, fatigue, failure to thrive as well as an increased risk of many serious diseases. Gluten may also have negative effects on the barrier function of the intestine, allowing unwanted substances to -leak‖ through into the bloodstream. Gluten containing diet can cause more pain, bloating, stool inconsistency and fatigue in patients with irritable bowel syndrome. Many Brain Disorders like CASIRJ
Analytical and functional approaches to assess the immunogenicity of gluten proteins
Frontiers in Nutrition
Gluten proteins are the causative agents of celiac disease (CD), a lifelong and worldwide spread food intolerance, characterized by an autoimmune enteropathy. Gluten is a complex mixture of high homologous water-insoluble proteins, characterized by a high content of glutamine and proline amino acids that confers a marked resistance to degradation by gastrointestinal proteases. As a consequence of that, large peptides are released in the gut lumen with the potential to activate inflammatory T cells, in CD predisposed individuals. To date, several strategies aimed to detoxify gluten proteins or to develop immunomodulatory drugs to recover immune tolerance to gluten are under investigation. This review overviews the state of art of both analytical and functional methods currently used to assess the immunogenicity potential of gluten proteins from different cereal sources, including native raw seed flours and complex food products, as well as drug-treated samples. The analytical design ...
Advances in the Understanding of Gluten related Pathology and the Evolution of Gluten-Free Foods
2015
More than 70% of people with coeliac disease remain undiagnosed, what means they become chronic patients who experience a decrease in their quality of life associated with different gluten-derived health problems occurring over time. This represents extra charges for the public health system that should also be noted. Research Finally, the investigation of gluten-related disorders is a key aspect for this Association, as it is crucial to improve our knowledge of these pathologies to get better diagnostic approaches and healthier and better quality glutenfree products. • The Association gets updated by reviewing scientific publications periodically and attending the most relevant scientific meetings and events concerning coeliac disease and gluten-free diet around the world. Thus, associated members, health-care professionals, researchers and people in general have a good point of information at this Association. • To promote research in the field, the Association has been awarding Spanish researchers with up to 24,000 Euro per year since 2003. More than 240,000 Euro have been invested along these years giving support to 13 Spanish research groups.
Proposal of International Gluten Research Group
Advances in Wheat Genetics: From Genome to Field, 2015
In a scenario of climate change and rapidly rising urban populations demanding processed foods, it is necessary to develop new wheat cultivars combining high yield potential, disease resistance, and stability for yield and processing quality, even under heat or drought stress conditions. Allelic variation for gluten proteins (glutenin subunits and gliadins) is a major determinant of differences in dough viscoelastic properties observed between cultivars of both bread wheat and durum wheat. Technical diffi culties in allelic identifi cation due to the complexity of the protein profi le produced by each cultivar and the use of different nomenclature systems in different laboratories has historically interfered with information exchange between research groups, a situation exacerbated by the vast number of possible profi les found in different cultivars due to the multi-allelic nature of the principal loci encoding gluten proteins (Glu-1 , Glu-2, Glu-3 , Gli-1 and Gli-2). For the Glu-3 alleles, we have collaborated to unify criteria across laboratories and to
Journal of Agricultural and Food Chemistry, 2013
Tissue transglutaminase (TG2) plays a central role in celiac disease (CD) pathogenesis by strongly enhancing the immunogenicity of gluten, the CD-triggering antigen. By deamidating specific glutamine (Q) residues, TG2 favors the binding of gluten peptides to DQ2/8 molecules and, subsequently, their recognition by cognate T cells. Six peptides were previously identified within wheat gliadin whole extracts by tagging the TG2-susceptible Q residues with monodansylcadaverine (MDC) and nanospray tandem mass spectrometry (nanoESI-MS/MS). The immunogenicity of these peptides was next tested in gliadinspecific T-cell lines established from CD intestinal mucosa. Four peptides, corresponding to known epitopes of αand γ-gliadins, induced cell proliferation and interferon (IFN)-γ production. Interestingly, one of the two non-T-cell stimulatory peptides corresponded to the 31−49 α-gliadin peptide implicated in the innate immune activation in CD mucosa. This study describes a strategy for identifying immunogenic gluten peptides potentially relevant for CD pathogenesis in protein extracts from wheat and other edible cereals.