Abstract:Extracellular vesicles are one of the important functional components in breast milk, and previous studies in the author's lab have found that breast milk extracellular vesicles (BM-EVs) could significantly promote the growth of Bifidobacterium lactis BB-12(B. lactis BB-12). However, the specific mechanism is unclear. In this study, BM-EVs were extracted from human milk using the combination of ultracentrifugation and ultrafiltration methods, and were characterized by nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and Western-blot analysis. Transcriptome data analysis was used to explore and identify the key genes of BM-EVs promoting the growth of B. lactis BB-12. The results showed that after BM-EVs intervention, the expression levels of ABC oligopeptide transport system-related genes pstC, pstA, metI in B. lactis BB-12 were significantly increased, as well as starch and sucrose metabolism-related genes BIF_02090, pentose phosphate pathway-related genes prsA and BIF_01321, D-amino acid metabolism-related genes murD and BIF_02122, and Glyoxylate and dicarboxylate metabolism- related gene pccA. In summary, BM-EVs may serve as a new type of prebiotic to promote the growth of Bifidobacterium in the intestine of infants，providing a theoretical basis for the development and application in next generation infant formula milk powder.
