Elucidating the molecular, structural and supramolecular basis of 33-mer gliadin oligomers and their role in gluten-related disorders

33聚体醇溶蛋白多肽是面筋相关疾病的关键因素，面筋相关疾病是一组免疫疾病，在西方社会中发病率很高(1-7%)。这种33聚体氨基酸是小麦面筋蛋白中醇溶蛋白不完全蛋白分解的产物，它具有面筋免疫显性序列，可在易感个体中触发自身免疫。然而，触发面筋相关疾病的分子事件还没有被描述。我们发现α-醇溶蛋白混合物和33-聚醇溶蛋白多肽在生理条件下能够形成可溶的寡聚体和超结构。重要的是，我们发现33肽在自组装过程中经历了向平行β-Sheet结构的结构转变。寡聚化和平行的β-折叠结构形成是淀粉样变性的特征。此外，我们还证明了33聚体的超结构激活了由Toll样受体(TLRs)介导的巨噬细胞的天然免疫反应。从这个意义上说，我们的工作假设是，33肽的积累和聚集可能是触发疾病的一个未知的关键因素。因此，本项目的目的是阐明33-聚体齐聚的分子、结构和超分子基础，以及33-聚体纳米结构在肠道上皮细胞模型中相互作用和运输的行为。这个多学科项目结合了不同的方法，包括多肽化学、结构和超分子表征、细胞生物学方法、蛋白质组学和超分辨率光学显微镜。这些方法的结合是量化和了解33聚体低聚物和超结构作为疾病触发因素的作用的双赢策略。我们的发现将为理解与面筋有关的疾病开辟新的途径，旨在设计除无面筋饮食之外的新的有效治疗方法。

The 33-mer gliadin peptide is a key player in the context of gluten-related disorders, a group of immunological disorders with a high prevalence in Western societies (1-7%). This 33-mer amino acid is the product of the incomplete proteolysis of gliadins present in wheat gluten and it possesses the gluten-immunodominant sequence that triggers autoimmunity in susceptible individuals. Nevertheless, the molecular events triggering gluten-related disorders have not been described yet. We showed that the α-gliadin mixtures and the 33-mer gliadin peptide are able to form soluble oligomers and superstructures under physiological conditions. Importantly, we discovered that the 33-mer peptide suffers a structural transition towards a parallel β-sheet structure during the self-assembly process. Oligomerisation and a parallel beta-sheet structure formation are the hallmarks of amyloidosis. Moreover, we demonstrated that the 33-mer superstructures activate the innate immune response in macrophages mediated by Toll-like Receptors (TLRs). In this sense, our working hypothesis is that the accumulation and aggregation of the 33-mer peptide could be an unknown and key factor which triggers the disease. Therefore, the aim of this project is to elucidate the molecular, structural and supramolecular basis of 33-mer oligomerization and the behaviour of the 33-mer nanostructures in their interaction and transport in gut epithelial cell models. This multidisciplinary project combines different methodologies including peptide chemistry, structural and supramolecular characterisation, cellular biology approaches, proteomics and super-resolution optical microscopy. The combination of these methodologies is the win-win strategy to quantify and understand the role of the 33-mer oligomers and superstructures as triggers of the disease. Our findings will open new avenues in the understanding of gluten-related disorders directed towards the design of new effective treatments beyond the gluten-free diet.