Nano-plastics disrupt systemic metabolism by remodeling the bile acid-microbiota axis and driving hepatic-intestinal dysfunction

The pervasiveness of microplastic pollution poses a growing health risk, yet its long-term metabolic consequences remain poorly defined. Here, we exposed mice to polyethylene terephthalate nanoparticle (NP) and combined histopathology, biochemistry, metabolomics, and metagenomics to resolve their interactions. NP ingestion induced a severe systemic phenotype characterized by weight loss, organ atrophy, dyslipidemia, and gut barrier collapse. Mechanistically, NPs disrupted bile acid (BA) homeostasis by hyperactivating hepatic synthesis pathways while suppressing microbial 7α-dehydroxylation. This accumulation of cytotoxic BAs drove hepatic lipogenesis and aggravated mucosal inflammation. Crucially, metagenomics uncovered significant gut microbiota dysbiosis, where the enrichment of bile salt hydrolase-encoding taxa and depletion of 7α-dehydroxylating clades reinforced this BA imbalance. Furthermore, the microbiota exhibited functional deterioration, shifting toward glycan degradation with a concurrent loss of antibiotic resistance genes, signaling reduced ecological resilience. These findings identify BA dysregulation and specific microbiota functional losses as primary drivers of NP-induced systemic metabolic collapse.