MiRNA-320a is less expressed and miRNA-148a more expressed in preterm human milk compared to term human milk

Objectives: To investigate whether there is a difference in the profile of miRNAs between human milk (HM) from mothers of preterm versus HM from mothers of full-term infants. Second goal is to assess biological functions or implication related to those differences in miRNAs expression. Methods: Four of the highly expressed miRNAs in milk were detected by qRT-PCR. Milk derived exosomes were incubated with cells. The expression of miRNAs and target gene were detected by qRT-PCR. Results: MiRNA-320 was more highly expressed in the colostrum of fullterm than in preterm HM. The expression of MiRNA-148 was higher in preterm mother's milk than of full-term colostrum. MiRNA-320 and MIRNA-148a expression were upregulated in cells incubated with milk exosomes, which lead to a decrease in their target genes FASN1 and DNMT1 respectivilly. Conclusions: Alterations in miRNAs expression in HM can affect biologic function in infants and may serve as a nutritional therapeutic target.