RESUMO
【Objective】 To evaluate the differential miRNA expression of breast milk exosome in premature and full-term groups, and to analyze the regulatory pathways by bioinformatics, so as to provide guidance and scientific basis for the growth and development of premature infants and the prevention and treatment of related diseases. 【Methods】 From August 2020 to June 2021, breast milk samples from 13 premature (premate group) and 9 full-term infants(full-term group) in the Department of Child Health Care of the Second Affiliated Hospital of Nanjing Medical University were collected to extract exosomes. The miRNAs of two groups of breast milk exosomes were sequenced by high-throughput sequencing. According to the sequencing results, miRNA expression profiles of milk exosome were analyzed. Biological function software was used to carry out GO and KEGG pathway analysis of differential miRNA. 【Results】 The expression of miRNA in human milk exosomes was rich, especially hsa-miR-148a-3p,hsa-let-7b-5p, hsa-let-7g-5p, hsa-miR-22-3p, hsa-miR-99a-5p, hsa-miR-200, hsa-miR-146b-5p and hsa-miR-26a-5p were relatively high expressed in preterm group and full-term group. Differential expression analysis showed that compared with full-term infant breast milk, 7 miRNAs were up-regulated(log2|fold change|=2.803, 2.714, 1.632, 2.360, 1.350, 3.387, 2.137, respectively), and 5 miRNAs were down-regulated(log2|fold change|=-2.553, -2.197, -2.771, -1.395, -1.136, respectively)(|fold change>2|, P<0.05) in breast milk for preterm infants. In these differential expressed miRNAs, down-regulated miR-29b(P=0.001) and up-regulated miR-133a-3p(P=0.004) were associated with inflammation, and up-regulated miR-126-5p(P=0.021) and miR-126-3p(P=0.041) were associated with lipid metabolism. The fatty acid biosynthesis pathway was obviously enriched in preterm group. MiR-7-5p, miR-29b-3p and miR-100-5p played a role in the fatty acid synthesis pathway. 【Conclusions】 Exosomal miRNAs are rich in breast milk, and have significant differences between preterm and full-term infants′ mothers. The differentially expressed miRNA in preterm infants treast milk may be related to inflammation and promote the growth and development of preterm infants through the fatty acid biosynthesis pathway.