GSE124182
Long-chain saturated fatty acids in breast milk are associated with the pathogenesis of atopic dermatitis via inducing inflammatory ILC3s
Breastfeeding is thought to influence the immune system development of infants and may even affect various immunological responses later in life. Breast milk provides a rich source of early nutrition for the growth and developmental of infants. However, the presence of certain compounds in breast milk related to an unhealthy lifestyle or the diet of lactating mothers may negatively impact infants6. Based on a cohort study, we found that the composition of mother's milk containing high amount of long-chain saturated fatty acids (LCSFAs) was related to a higher incidence of atopic dermatitis (AD) in children. Similarly, a mouse model in which breastfed offspring were fed milk high in LCSFAs also resulted in AD onset later in life. We showed that LCSFAs are damage-associated molecular patterns, which initiate a series of inflammatory events in the gut involving type 3 innate lymphoid cells (ILC3s). A remarkable increase in inflammatory ILC3s was observed in the gut, and the migration of these ILC3s to the skin contributed to the pathogenesis of AD. Gene expression analysis of ILC3s isolated from the gut revealed up-regulation of genes that increase ILC3s and chemokines, which may play a role in ILC migration to the skin. Even in the absence of adaptive immunity, Rag1 knockout mice fed a high-LCSFA milk diet developed eczema, accompanied by increased gut ILC3s. Here, we propose that early exposure to LCSFAs in infants may affect the balance of intestinal innate immunity, inducing a highly inflammatory environment with the proliferation of ILC3s and production of interleukin-17 and interleukin-22, which are attributed to the pathogenesis of AD. Overall design: Examination of ILC3s from intraepithelial and lamina propria layer of two different mice groups, comparison between normal or fed with maternal milk with high saturated fatty acids