Nanoplastics target lung monocytes, disrupting immune dynamics

Using whole-animal fluorescence imaging, flow cytometry, and single-cell RNA sequencing of nanoplastic-partitioned cells, we investigated the biodistribution and direct cellular interactions of nanoplastics in mice following systemic exposure. Unlike microplastics and iron nanoparticles, nanoplastics predominantly localize to the lung.

In the lung, these nanoplastics selectively sequester resident nonclassical monocytes and a distinct subpopulation of CD206- interstitial macrophages. Notably, macrophages sequestering nanoplastics display a delayed transition from nonclassical monocytes, characterized by persistent expression of Plac8, Treml4, and Ace. Additionally, depletion of blood monocytes induces a compensatory expansion of lung classical monocytes, which subsequently assume roles in nanoplastic sequestration.