Potential Effect Of Human Milk Exosomal MiRNAs On Breast Milk Jaundice Through Regulating Intestinal Flora

Objective: To analyze the characteristics of intestinal flora in infants with breast-milk jaundice,and screen the breast milk exosome microRNAs which have interaction sites with different bacteria,suggesting that microRNAs may affect the occurrence and development of breast milk jaundice by regulating intestinal flora.Methods: Infants with hyperbilirubinemia caused by breast milk jaundice that enrolled in Shanghai Children’s Medical Center affiliated to Shanghai Jiaotong University Medical College from January 2018 to June 2018 were experimental group.Jaundice-free newborns fed exclusively by breast milk in Shanghai UIB International Maternity Care Center were used as the control group,with 10 cases in each group.Breast milk and fecal samples of newborns were collected.In this study,16 S rRNA high-throughput sequencing was used to analyze the characteristics of intestinal flora in two groups of stool samples,screening the differentiated bacteria which may be related to neonatal bilirubin metabolism.Then the exosomes extracted from breast milk were identified by transmission electron microscopy and Western blotting.We predicted microRNAs interacting with the differentiated bacterial genomes through the miRBase database.Quantitative PCR was used to verify the difference of expression of predicted microRNAs in breast milk exosomes,and to explore the correlation between differentially expressed microRNAs in breast milk and intestinal flora.Results:(1)The 16 S rRNA sequencing of intestinal flora showed that there was no significant difference in the diversity of intestinal bacteria between breast milk jaundice children and the control group.For infants with breast milk jaundice,firmicutes and Haemophilus were lower than control group,while proteobacteria,Escherichia,Morganella and Rothia were higher.Escherichia coli(E.coli)may be an important strain affecting bilirubin enterohepatic circulation.(2)The miRBase database indicated that there were interaction sites between hsa-miR-16-5p and E.coli genome.The expression of hsa-miR-16-5p in breast milk exosome was decreased in breast milk jaundice group by quantitative PCR.Conclusions: miR-16-5p in breast milk exosome may play a potential role in regulating the growth of E.coli by combining the intestinal microbial genome,affecting bilirubin enterohepatic circulation and providing evidence for the pathogenesis of breast milk jaundice.