Pepsin Digest of Gliadin Forms Spontaneously Amyloid-Like Nanostructures Influencing the Expression of Selected Pro-Inflammatory, Chemoattractant, and Apoptotic Genes in Caco-2 Cells: Implications for Gluten-Related Disorders

Scope Proteolysis-resistant gliadin peptides are intensely investigated in biomedical research related to Celiac Disease and gluten-related disorders. Herein, the first integrated supramolecular investigation of pepsin-digested gliadin peptides, p-gliadin, is presented in combination with its functional behavior in Caco-2 cell line. Methods and results First, we investigated gliadin degradation by pepsin at pH 3, and the physicochemical properties of p-gliadin were compared with gliadin. An integrated approach using interfacial, spectroscopic, and microscopic techniques revealed that the p-gliadin forms spontaneously soluble large supramolecular structures, mainly oligomers and fibrils capable of binding amyloid-sensitive dyes. The self-assembly of p-gliadin starts at a concentration of 0.40 μg/ml. Second, we stimulated CaCo-2 cells with the p-gliadin supramolecular system and screened the mRNA expression levels of a panel of genes involved in cellular inflammation, apoptosis, permeability, and chemoattraction of immune cells. Our findings suggest that p-gliadin composed of supramolecular structures triggers significant mRNA up-regulation (p Conclusions This work demonstrates that p-gliadin is interfacial active, forming spontaneously amyloid-type structures that trigger genes in the Caco-2 cell line involved in the recruitment of specialized immune cells. This article is protected by copyright. All rights reserved.