Abstract
BACKGROUND: Colostrum is well known to have excellent nutritional value for newborns. The aim of this study was to investigate the dynamic expression pattern of microRNA in human colostrum and mature milk. Furthermore, we identified the specific microRNA in human colostrum and analyzed the regulatory function of human colostrum. METHODS: We collected breast milk samples from 18 lactating volunteers. The expression of microRNA in breast milk was detected by microarray analysis. The expression differences were characterized by log2FC (|log2fold change| >1.58) and associated P values (P<0.05). Furthermore, the prediction of microRNA targets, bioinformatics analysis and network generation were carried out using network database. RESULTS: Our results showed that during the human lactation process, the composition of microRNAs in human milk changes dynamically. Compared to the microRNA expression profile in human mature milk, the expression levels of 49 microRNAs were significantly different and 67 microRNAs were specifically expressed in human colostrum. Based on the results of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, the predicted target mRNAs of the identified colostrum-specific microRNAs were involved in the regulation of distinct biological processes, such as signal transduction, positive regulation of GTPase activity, and protein phosphorylation. Moreover, the predicted mRNA targets were from large spectrums of signaling pathways, such as the MAPK, Ras, Hippo, Wnt, and mTOR signaling pathways, as well as the longevity regulating pathway. CONCLUSIONS: Our study illuminates the landscape of microRNA expressions in human colostrum and mature milk, and emphasizes the value of microRNAs as nutritional additives in milk-related commercial products.