Prebiotic Oligosaccharides Potentiate Host Protective Responses against L. Monocytogenes Infection

Abstract

Prebiotic oligosaccharides are used to modulate enteric pathogens and reduce pathogen shedding. The interactions with prebiotics that alter Listeria monocytogenes infection are not yet clearly delineated. L. monocytogenes cellular invasion requires a concerted manipulation of host epithelial cell membrane receptors to initiate internalization and infection often via receptor glycosylation. Bacterial interactions with host glycans are intimately involved in modulating cellular responses through signaling cascades at the membrane and in intracellular compartments. Characterizing the mechanisms underpinning these modulations is essential for predictive use of dietary prebiotics to diminish pathogen association. We demonstrated that human milk oligosaccharide (HMO) pretreatment of colonic epithelial cells (Caco-2) led to a 50% decrease in Listeria association, while Biomos pretreatment increased host association by 150%. L. monocytogenes-induced gene expression changes due to oligosaccharide pretreatment revealed global alterations in host signaling pathways that resulted in differential subcellular localization of L. monocytogenes during early infection. Ultimately, HMO pretreatment led to bacterial clearance in Caco-2 cells via induction of the unfolded protein response and eIF2 signaling, while Biomos pretreatment resulted in the induction of host autophagy and L. monocytogenes vacuolar escape earlier in the infection progression. This study demonstrates the capacity of prebiotic oligosaccharides to minimize infection through induction of host-intrinsic protective responses.

Food authentication from shotgun sequencing reads with an application on high protein powders

“…On the day of arrival 0.2 g of powder was added to 2 mL of Trizol LS (Ambion by Life Technology, Carlsbad, CA). After complete mixing, the samples were used to extract total RNA as described by Chen et al 23 and total DNA as described elsewhere. 24–29 Total RNA purity (A 260/230 and A 260/280 ratios ≥ 1.8) and integrity were confirmed with Nanodrop (Nanodrop Technologies, Wilmington, DE, USA) and BioAnalyzer RNA Kit (Agilent Technologies Inc., Santa Clara, CA, USA).…”

“…24–29 Total RNA purity (A 260/230 and A 260/280 ratios ≥ 1.8) and integrity were confirmed with Nanodrop (Nanodrop Technologies, Wilmington, DE, USA) and BioAnalyzer RNA Kit (Agilent Technologies Inc., Santa Clara, CA, USA). 23 Subsequently, cDNA was constructed using RNA (4–15 µg total input) and SuperScript Double Stranded cDNA Synthesis kit (Invitrogen, Catalog no. 11917-020, Life Technology, Carlsbad, CA).…”

“…Sequencing libraries using HyperPrep Plus (Kapa BioSystems, Wilmington, MA, USA) cDNA were constructed as described previously 23,30,31 with an insert size between 300 and 400 bp. Library quantification was done using qPCR (Library Quantification kit catalog #KK4824, Illumina, San Diego, CA) prior to submission for sequencing at BGI@UC Davis (Sacramento, CA).…”

Immunological Effects of Human Milk Oligosaccharides

“…However, not always is the beneficial effect of HMOs to bacterial infection arising from preventing association or invasion of the pathogen. For example, HMOs can alter gene expression in intestinal cells that can block infection of Listeria monocytogenes ( 101 ), or have a direct effect on the growth of pathogens as was shown for neutral HMOs and especially LNT and LNFP I against group B Streptococcus ( 102 ). Similarly, HMOs were shown to modulate hyphal induction in Candida albicans, which is necessary for invasion of the intestinal epithelium ( 103 ).…”

In Love with Shaping You—Influential Factors on the Breast Milk Content of Human Milk Oligosaccharides and Their Decisive Roles for Neonatal Development

“…These proteins (or protein motifs) are called lectins and recognize specific moieties of surface-exposed glycans either on host or pathogen cells, which resemble HMO fragments or individual HMOs. Thus, indigestible mother milk sugars act as soluble decoy receptors that interfere with the lectin-glycan association for pathogens such as Entaboeba histolytica [ 65 ], Campylobacter jejuni [ 66 , 67 ], Clostridium difficile [ 68 , 69 ], enterohaemorrhagic [ 70 ], entereopathogenic [ 71 , 72 , 73 , 74 , 75 , 76 , 77 ], enterotoxic [ 78 ], uropathogenic [ 78 , 79 , 80 ] Escherichia coli [ 81 ], Helicobacter pylori [ 82 ], L. monocytogenes [ 83 ], Neisseria Meningitidis C [ 84 ], Pseudomonas aeruginosa [ 75 , 85 , 86 ], Salmonella enterica [ 74 , 75 ], Staphylococcus aureus [ 87 ], Vibrio cholerae [ 70 , 74 , 88 ], human immunodeficiency virus [ 89 ], influenza virus [ 90 , 91 ], norovirus [ 92 , 93 , 94 ] and respiratory syncytial virus [ 95 ]. Table 3 summarizes HMOs that have been shown to block pathogen adhesion in vitro.…”