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

HERRERA, MARIA GEORGINA; NICOLETTI, FRANCESCO; GRAS, MARION; DÖRFLER, PHILIPP W.; TONALI, NICOLO; HANNAPPEL, YVONNE; ENNEN, INGA; HÜTTEN, ANDREAS; HELLWEG, THOMAS; LAMMERS, KAREN M.; DODERO, VERONICA I.

MOLECULAR NUTRITION & FOOD RESEARCH

WILEY-V C H VERLAG GMBH

Año: 2021 vol. 65

1613-4125

Scope: Proteolysis-resistant gliadin peptides are intensely investigated in biomedical research relates 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 the Caco-2 cell line. Methods and Results: First, gliadins are degraded by pepsin at pH 3, and the physicochemical properties of p-gliadin are compared with gliadin. An integrated approach using interfacial, spectroscopic, and microscopic techniques reveals 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−1. Second, the stimulation of Caco-2 cells with the p-gliadin supramolecular system is performed, and the mRNA expression levels of a panel of genes are tested. The experiments show that p-gliadin composed of supramolecular structures triggers significant mRNA up-regulation (p < 0.05) of pro-apoptotic biomarkers (ratio Bcl2/Bak-1), chemokines (CCL2, CCL3, CCL4, CCL5, CXCL8), and the chemokine receptor CXCR3. 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 recruiting specialized immune cells.