Glycosylation of Human Milk Lactoferrin Exhibits Dynamic Changes During Early Lactation Enhancing Its Role in Pathogenic Bacteria-Host Interactions

Abstract

Human milk lactoferrin (hmLF) is the most abundant glycoprotein present in human milk and displays a broad range of protective functions in the gut of newborn infants. hmLF is N-glycosylated, but little is known about the lactation stage-related development of the glycosylation phenotype. hmLF glycosylation from milk samples from five donors during the first 10 weeks of lactation was assessed and observed to be more diverse than previously reported. During this period dynamic changes in glycosylation were observed corresponding to a decrease in glycosylation in the second week followed by an increase in total glycosylation as well as higher order fucosylation thereafter. Gene expression analysis was performed in milk somatic cells from a sixth subject. It was found that fucosyltransferase expression increased during entire period, whereas expression of genes for the oligosaccharyl transferase complex decreased in the second week. The effect of hmLF glycosylation was examined for the protein's ability to affect bacterial binding to epithelial cells. hmLF significantly inhibited pathogen adhesion and purified hmLF glycans significantly reduced

Consumption of human milk glycoconjugates by infant-associated bifidobacteria: mechanisms and implications

“…There are two major types of oligosaccharides attached to eukaryotic proteins: N-linked and O-linked glycans. These conjugated carbohydrates play several biochemical and physiological roles, for example in protein synthesis, folding, trafficking and secretion, resistance to proteolysis, and prevention of pathogen colonization of epithelial surfaces among several others (Barboza et al, 2012;Gopal & Gill, 2000;Newburg et al, 2005;Peterson et al, 1998;Rudd et al, 1994). In human milk a large number of human milk proteins are glycosylated, including lactoferrin, immunoglobulins and k-casein among several others .…”

Endo-β-N-acetylglucosaminidases from Infant Gut-associated Bifidobacteria Release Complex N-glycans from Human Milk Glycoproteins

“…Milk proteins are readily utilized by the infant (9) and are also critical in the protection of the newborn. For example, human lactoferrin (hLF) is one of the most abundant proteins in human milk, and hLF and its derived peptides display broad antimicrobial and anti-inflammatory effects, among several other biological activities (10,11).…”

Rapid Quantification of Functional Carbohydrates in Food Products

“…This result shows that the kit can detect the different complex N-glycans attached to the protein. Different N-glycan compositions have been previously identified, including high mannose, hybrid and complex N-glycan types [12,15]. Lactoferrin exhibits an array of biological activities [16][17][18][19], which are modulated by both the polypeptide chain and its glycosylated moiety [12].…”

“…BMO samples were rehydrated in 1 mL of water and diluted one hundred fold prior to mass spectrometry analysis. Lactoferrin was purified from donor human milk by affinity chromatography as described by Barboza et al, (2012) [12]. The purity of the protein was monitored by sodium dodecyl sulfate gel electrophoresis (data not shown).…”