Determination of hyaluronan molecular mass distribution in human breast milk.
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ABSTRACT: Hyaluronan (HA) in human milk mediates host responses to microbial infection via TLR4- and CD44-dependent signaling. Signaling by HA is generally size specific. Because pure HA with average molecular mass (M) of 35 kDa can elicit a protective response in intestinal epithelial cells, it has been proposed that human milk HA may have a bioactive low-M component. Here we report the size distribution of HA in human milk samples from 20 unique donors. A new method for HA analysis, employing ion exchange (IEX) chromatography to fractionate HA by size and specific quantification of each size fraction by competitive enzyme-linked sorbent assay (ELSA), was developed. When separated into four fractions, milk HA with M?20 kDa, M?20 to 60 kDa, and M?60 to 110 kDa comprised averages of 1.5, 1.4, and 2.0% of the total HA, respectively. The remaining 95% was HA with M?110 kDa. Electrophoretic analysis of the higher M HA from 13 samples showed nearly identical M distributions, with an average M of approximately 440 kDa. This higher M HA component in human milk is proposed to bind to CD44 and to enhance human beta defensin 2 (HBD2) induction by the low-M HA components.
SUBMITTER: Yuan H
PROVIDER: S-EPMC4357551 | biostudies-literature | 2015 Apr
REPOSITORIES: biostudies-literature
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