A Proteinaceous Fraction of Wheat Bran May Interfere in the Attachment of Enterotoxigenic E. Coli K88 (F4+) to Porcine Epithelial Cells

Abstract

Wheat bran (WB) from Triticum aestivum has many beneficial effects on human health. To the best of our knowledge, very little has been published about its ability to prevent pathogenic bacterial adhesion in the intestine. Here, a WB extract was fractionated using different strategies, and the obtained fractions were tested in different in vitro methodologies to evaluate their interference in the attachment of enterotoxigenic Escherichia coli (ETEC) K88 to intestinal porcine epithelial cells (IPEC-J2) with the aim of identifying the putative anti-adhesive molecules. It was found that a proteinaceous compound in the >300-kDa fraction mediates the recognition of ETEC K88 to IPEC-J2. Further fractionation of the >300-kDa sample by size-exclusion chromatography showed several proteins below 90 kDa, suggesting that the target protein belongs to a high-molecular-weight (MW) multi-component protein complex. The identification of some relevant excised bands was performed by mass spectrometry (MS) and mostly revealed the presence of various protease inhibitors (PIs) of low MW: Serpin-Z2B, Class II chitinase, endogenous alpha-amylase/subtilisin inhibitor and alpha-amylase/trypsin inhibitor CM3. Furthermore, an incubation of the WB extract with ETEC K88 allowed for the identification of a 7S storage protein globulin of wheat, Globulin 3 of 66 kDa, which may be one of the most firmly attached WB proteins to ETEC K88 cells. Further studies should be performed to gain an understanding of the molecular recognition of the blocking process that takes place. All gathered information can eventually pave the way for the development of novel anti-adhesion therapeutic agents to prevent bacterial pathogenesis.

Escherichia coli K88 activates NLRP3 inflammasome-mediated pyroptosis in vitro and in vivo

“…Escherichia coli K88 is a typical kind of ETEC expressing K4 adhesin [ 20 ], which has been widely used to construct inflammation models in piglets [ 21 ], broilers [ 22 ], mice [ 23 ], epithelial cells [ 24 ], and macrophages [ 25 ]. Our previous studies identified that E. coli K88 treatment upregulated the expression of reactive oxygen species and inducible nitric oxide synthase in RAW264.7 cells [ 26 ], promoted the inflammatory response, and disrupted the intestinal barrier in mice [ 27 , 28 ].…”

Ovomucin Hydrolysates Reduce Bacterial Adhesion and Inflammation in Enterotoxigenic Escherichia coli (ETEC) K88-Challenged Intestinal Epithelial Cells

“…Given that bacterial adhesion to the host cell surface is the initial step of pathogenesis, antiadhesive therapy provides a promising strategy to interfere with the interactions of microbes and toxins with host cells, inhibiting pathogenic colonization and infection . Various dietary components act as decoy receptors for pathogens and are considered safe to inhibit the development of multiresistant bacteria. , For example, peptide fractions from wheat bran and fermented soy bean extracts inhibited ETEC K88 binding to intestinal epithelial cells. Feed ingredients, including microbial exopolysaccharides − and casein macropeptide released during cheese making, were reported to reduce ETEC binding to the intestinal mucosa of piglets. , These studies indicated the potential of food-derived glycoconjugates as antiadhesive substances and antimicrobial alternatives to prevent pathogenic colonization and infection.…”