Oral Feeding of Nanoplastics affects Brain function of Mice by Inducing Macrophage IL-1 Signal in Intestine

Nanoplastics (NPs) as contaminants in food and water have drawn an increasing public attention. However, little is known about how NPs shape the gut immune landscape after injection. In this study, we fabricated NPs (∼500 nm) and microplastics (MPs) (∼2 μm) and evaluated them in vivo effects by feeding them in mice. The results suggested that NPs showed a better ability to induce gut macrophage activation than did MPs. In addition, NPs triggered gut interleukin 1 (IL-1)-producing macrophage reprogramming via inducing lysosomal damage. More importantly, IL-1 signaling from the intestine could affect brain immunity, leading to microglial activation and Th17 differentiation, all of which correlated with a decline in cognitive and short-term memory in NPs-fed mice. Thus, this study provides new insight into the mechanism of action of the gut-brain axis and delineates the way NPs reduce brain function, highlights the importance to fix the plastic pollution problem worldwide.