Detailed Characterization of Antipathogenic Properties of Human Milk N-Glycome, against Staphylococcus aureus, Indicating Its Targeting on Cell Surface Proteins

Abstract

Human milk N-glycome was previously identified to have strong antipathogenic activities. This study is aimed to characterize the detailed antibacterial properties and the potential function mechanism of human milk N-glycome against Staphylococcus aureus. A serials of traditional antibacterial assays showed that human milk N-glycome possessed both bacteriostatic and bactericidal activities, which was further confirmed by the cell structure disruption including the change of transmembrane potential and leakage of intracellular contents. The results of the bacterial surface zeta potential and hydrophobicity, bacterial binding assay, gel shift assay, and fluorescence spectra and the different synergistic effects of human milk N-glycome combined with different antibiotics indicated that the bacterial surface proteins could be the targets of human milk N-glycome. Moreover, human milk N-glycome also showed antibiofilm activity. In conclusion, human milk N-glycome exhibited good potential for acting as an antibacterial substance against S. aureus and the antibacterial mechanism was a cell surface targeting action.

Variations in Oligosaccharides and N/O-Glycans in Human Milk through the Eight-Month Lactation Period

“…13,14 In addition, oligosaccharides act as a metabolic substrate to shape the intestinal flora, 15−17 serve as antiadhesive antimicrobials, 18 and modulate epithelial and immune cell responses, thereby contributing to immune protection. 19,20 And N-glycans simultaneously contribute to antibacterial, antiviral, and immune system regulation, 21,22 and O-glycans affect the formation and stability of the intestinal microbiota and act as effective decoy receptors for pathogenic gastrointestinal bacteria and viruses. 23 The different glycans consumed in early life are suggested to be associated with differences in long-term health conditions and intelligence between breastfed and bottle-fed infants.…”

“…For instance, glycans provide sialic acid needed for the baby’s brain development . About 70–83% of all sialic acid present in human milk is bound with HMOs, 14–28% with glycoprotein glycans and 0.2–0.4% with glycolipids (primarily gangliosides). , In addition, oligosaccharides act as a metabolic substrate to shape the intestinal flora, − serve as antiadhesive antimicrobials, and modulate epithelial and immune cell responses, thereby contributing to immune protection. , And N -glycans simultaneously contribute to antibacterial, antiviral, and immune system regulation, , and O -glycans affect the formation and stability of the intestinal microbiota and act as effective decoy receptors for pathogenic gastrointestinal bacteria and viruses . The different glycans consumed in early life are suggested to be associated with differences in long-term health conditions and intelligence between breastfed and bottle-fed infants. − Hence, insights into the composition and variation of oligosaccharides and N / O -glycans in babies’ early life are urgently needed for the innovation and improvement of infant formula.…”