Hajime Nakatani, Takehiko Yasueda, Kenzi Oshima, Tetsuya Okajima, Daita Nadano, David J Flint, Tsukasa Matsuda
Journal of biochemistry 2013 JanMilk fat globules (MFGs) secreted by lactating mammary gland are unique lipid surrounded by a phospholipid bi-layer. We report here post-weaning changes in MFG EGF factor VIII (MFG-E8) and annexin V-accessible phosphatidyl-l-serine on the surface of MFGs. The MFG content in milk markedly decreased to about one-half within 2 days after forced weaning, despite a slight increase in milk protein content. Immunofluorescence-staining of MFGs using anti-MFG-E8 and annexin V indicated that MFG-E8 was present on some, but not all, MFGs before weaning, whereas most of MFGs were MFG-E8-positive and annexin V-negative after weaning. Free MFG-E8 with binding activity to phosphatidyl-l-serine was present abundantly in the post-weaning milk, and indeed exhibited binding to MFGs in pre-weaning milk. MFGs were taken up by HC11 mouse mammary epithelial cells in vitro, and those from post-weaning milk were remarkable for such cellular uptake. Moreover, the uptake of MFGs by the cells was inhibited by an anti-MFG-E8 antibody. Taken together, these findings suggest that MFG-E8 plays a critical role in regulation of MFG dynamics after weaning or during the suckling interval through the control of MFG-epithelial cell interaction in lactating mammary glands.
Hajime Nakatani, Takehiko Yasueda, Kenzi Oshima, Tetsuya Okajima, Daita Nadano, David J Flint, Tsukasa Matsuda. Post-weaning increases in the milk-fat globule EGF-factor VIII on fat globules in mouse milk and in the uptake of the fat globules by HC11 mammary epithelial cells. Journal of biochemistry. 2013 Jan;153(1):31-41
PMID: 23038672
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