Lactosomes: structural and compositional classification of unique nanometer-sized protein lipid particles of human milk.

摘要: Milk fat globules (MFGs) are accepted primarily as triacylglycerol delivery systems. The identification of nanometer-sized lipid-protein particles termed "lactosomes" that do not contain raises the question their possible functions. MFGs were isolated by slow centrifugation, and lactosomes ultracentrifugation at a density equivalent to plasma high-density lipoproteins (HDL) (d > 1.063 g/mL) from human milk obtained six volunteers different lactation stages. Isolated analyzed compared with for size distribution, lipidome, proteome, functional activity. Lactosomes early milk, day 8, found be similar in those mature >28 days, averaging ∼ 25 nm diameter. In total, 97 nonredundant proteins identified MFG lactosome fractions, 46 which unique fraction 29 fraction. fractions enriched immunomodulatory pathways. Unlike GM1-laden reconstituted HDL served positive control, lactosomal binding capacity cholera toxin was weak. Lipidomic analyses devoid gangliosides, unlike MFGs, but rich variety phospholipid species. data differences structure, composition, function between MFG, suggesting these two derived biosynthetic and/or secretory results reveal bioactive lipid-protein, nanometer-length scale particle is secreted into supply energy infant play unique, protective, regulatory roles.