Maternal nanoplastic ingestion induces an increase in offspring body weight through altered lipid species and microbiota

[Display omitted] •Maternal ingestion of NPs increase the body weight of progeny by the elevation of fat mass.•Maternal administration of NPs alters the lipid composition in breast milk and progeny plasma.•PLA2 inhibition restores the PS NP-induced changes in lipid composition and body weight.•PS NP induces obesity-like microbial distribution with no relation to the lipidomic changes. The rapidly increasing prevalence of obesity and overweight, especially in children and adolescents, has become a serious societal issue. Although various genetic and environmental risk factors for pediatric obesity and overweight have been identified, the problem has not been solved. In this study, we examined whether environmental nanoplastic (NP) pollutants can act as environmental obesogens using mouse models exposed to NPs derived from polystyrene and polypropylene, which are abundant in the environment. We found abnormal weight gain in the progeny until 6 weeks of age following the oral administration of NPs to the mother during gestation and lactation. Through a series of experiments involving multi-omic analyses, we have demonstrated that NP-induced weight gain is caused by alterations in the lipid composition (lysophosphatidylcholine/phosphatidylcholine ratio) of maternal breast milk and he gut microbiota distribution of the progeny. These data indicate that environmental NPs can act as obesogens in childhood.