Date Published: January 30, 2019
Publisher: Public Library of Science
Author(s): Bo Li, Alison Hock, Richard Y. Wu, Adam Minich, Steven R. Botts, Carol Lee, Lina Antounians, Hiromu Miyake, Yuhki Koike, Yong Chen, Augusto Zani, Philip M. Sherman, Agostino Pierro, Giovanni Camussi.
Necrotizing enterocolitis (NEC) is characterized by intestinal injury and impaired mucin synthesis. We recently showed that breast milk exosomes from rodents promote intestinal cell viability, epithelial proliferation, and stem cell activity, but whether they also affect mucus production is unknown. Therefore, the aim of this study was to investigate the effects of bovine milk-derived exosomes on goblet cell expression in experimental NEC and delineate potential underlying mechanisms of action. Exosomes were isolated from bovine milk by ultracentrifugation and confirmed by Nanoparticle Tracking Analysis and through the detection of exosome membrane markers. To study the effect on mucin production, human colonic LS174T cells were cultured and exposed to exosomes. Compared to control, exosomes promoted goblet cell expression, as demonstrated by increased mucin production and relative expression levels of goblet cell expression markers trefoil factor 3 (TFF3) and mucin 2 (MUC2). In addition, exosome treatment enhanced the expression of glucose-regulated protein 94 (GRP94), the most abundant intraluminal endoplasmic reticulum (ER) chaperone protein that aids in protein synthesis. Furthermore, experimental NEC was induced in mouse pups by hyperosmolar formula feeding, lipopolysaccharide administration and hypoxia exposure on postnatal days 5–9. Milk exosomes were given with each gavage feed. NEC was associated with ileal morphological injury and reduction in MUC2+ goblet cells and GRP94+ cells per villus. Exosome administration to NEC pups prevented these changes. This research highlights the potential novel application of milk-derived exosomes in preventing the development of NEC in high-risk infants when breast milk is not available.
Necrotizing enterocolitis (NEC) is a devastating intestinal disease in premature and very low birth weight infants with a mortality rate of up to 50% . This gastrointestinal disease ranges in severity, from ileal and/or colonic inflammation to intestinal perforation, extensive necrosis, multiple organ failure, and death.
We have established an effective method for extracting and characterizing exosomes from milk. We have shown that exosomes promote intestinal epithelial cell viability, enhance proliferation, and stimulate intestinal stem cell activity under healthy conditions . We have previously demonstrated that exosome-free supernatant after ultracentrifugation does not convey a protective effect, hence confirming a principal role for the exosomes in mediating the above positive effects . In the present study, we extended our initial investigations by studying the effects of milk-derived exosomes administration during the induction of intestinal injury, such as NEC. We demonstrated that fortification of formula with bovine milk-derived exosomes counteracts the intestinal damage associated with experimental NEC by preventing the progression of intestinal injury and increasing goblet cell and ER functions.