Polypropylene nanoplastics (PP-NPs) are emerging environmental contaminants, but their gestational toxicity and underlying mechanisms remain poorly understood. In this study, we integrated maternal exposure mouse models, HTR8/SVneo trophoblast assays, quantitative proteomics, and phosphoproteomics to delineate the pathogenic basis of PP-NP-induced placental injury. PP-NPs accumulated prominently in the placenta, eliciting placental structural disruption, reduced placental efficiency, impaired fetal growth, and increased embryo loss. In trophoblasts, PP-NPs were readily internalized and impaired viability, proliferation, migration, invasion, and tube formation, accompanied by mitochondrial damage. To decipher the underlying molecular mechanisms, we performed integrated quantitative proteomic and phosphoproteomic analyses. These multi-omics landscapes revealed that cellular senescence is the dominant pathogenic program triggered by PP-NPs, accompanied by extensive phosphorylation remodeling. CDK1 emerged as the top predicted upstream kinase within this senescence-associated network. Notably, although CDK1 abundance was increased after PP-NPs exposure, its canonical cell-cycle-driving activity was not effectively engaged, as evidenced by reduced Thr161 phosphorylation, weakened CDK1-CCNB1 complex formation, and G1-phase arrest. Instead, PP-NPs were associated with increased phosphorylation of senescence-related substrates linked to CDK1-predicted signaling, including RBL2 at Thr642, SQSTM1 at Ser207, and FOXO3 at Ser284, together with activation of DNA damage signaling, the P53-P21/P16 axis, and a SASP-like inflammatory response. Pharmacological inhibition of CDK1 with Ro-3306 attenuated trophoblast senescence, restored trophoblast function, alleviated placental injury, and improved fetal outcomes in vivo, while siRNA-mediated CDK1 knockdown similarly suppressed CDK1-linked phosphorylation and rescued senescence-associated functional defects in trophoblasts. In conclusion, our study demonstrates that PP-NPs drive premature placental ageing through global proteomic and phosphoproteomic reprogramming, providing a new theoretical basis and potential therapeutic targets for environmental pollutant-induced adverse pregnancy outcomes.
