Bromelain and ficin proteolytic effects on gliadin cytotoxicity and expression of genes involved in cell-tight junctions in Caco-2 cells

Abstract

Enzyme therapy for celiac disease (CeD), which digests gliadin into non-immunogenic and non-toxic peptides, can be an appropriate treatment option for CeD. Here, we have investigated the effectiveness of bromelain and ficin on gliadin digestion using in vitro, such as SDS-PAGE, HPLC, and circular dichroism (CD). Furthermore, the cytotoxicity of gliadin and 19-mer peptide before and after digestion with these enzymes was evaluated using the MTT assay in the Caco-2 cell line. Finally, we examined the effect of these treatments along with Larazotide Acetate on the expression of genes involved in cell-tight junctions, such as Occludin, Claudin 3, tight junction protein-1, and Zonulin in the Caco-2 cell line. Our study demonstrated bromelain and ficin digestion effects on the commercial and wheat-extracted gliadin by SDS-PAGE, HPLC, and CD. Also, the cytotoxicity results on Caco-2 showed that toxicity of the gliadin and synthetic 19-mer peptide was decreased by adding bromelain and ficin. Furthermore, the proteolytic effects of bromelain and ficin on gliadin indicated the expression of genes involved in cell-tight junctions was improved. This study confirms that bromelain and ficin mixture could be effective in improving the symptoms of CeD.