Breast milk-derived extracellular vesicle miRNAs are associated with maternal asthma and atopy

Background: Breast milk-derived extracellular vesicle (EV) miRNAs may program child health outcomes associated with maternal asthma and atopy. The authors investigated associations between maternal asthma/atopy and EV miRNAs in the Programming of Intergenerational Stress Mechanisms cohort. Methods: Breast milk-derived EV miRNAs collected 6.1 +/- 5.9 weeks postnatally (n = 80 mothers) were profiled using the TaqMan OpenArray Human MicroRNA Panel. The authors assessed associations using adjusted robust regression. Results: Nine EV miRNAs were associated with asthma during pregnancy (a priori criteria: nominal p B-regression| >0.2). miR-1290 was associated with asthma and atopy during pregnancy (p B-regression| >0.2). Enriched Kyoto Encyclopedia of Genes and Genomes pathways included TGF-beta signaling and extracellular matrix-receptor interaction (false discovery rate <0.05). Conclusion: In this study, maternal asthma and atopy were associated with breast milk-derived EV miRNAs. Additional studies are needed to understand whether EV miRNAs have direct effects on infant and child health. Plain language summary Maternal asthma is associated with child health outcomes, although the biological mechanisms involved are not fully understood. miRNAs are small molecules involved in regulating gene expression. miRNAs packaged into membrane-bound particles called extracellular vesicles (EVs) are present in human breast milk and may pass from mother to infant to signal which genes to translate into proteins. This study investigated the extent to which maternal asthma and atopy influenced levels of 130 EV miRNAs measured in breast milk. Nine EV miRNAs were associated with maternal asthma during pregnancy, and one EV miRNA was associated with maternal atopy. miRNAs associated with asthma target genes in pathways related to asthma; however, future research is needed to determine whether changes in breast milk-derived EV miRNAs impact child health.