Network Toxicology Integrates In Vivo Evidence Linking Impaired Autophagic Clearance Involving the MTOR-TFEB Axis to Polystyrene Nanoplastic-Induced Neurotoxicity

Long-term exposure to polystyrene nanoplastics (PS-NPs) causes neurotoxicity, but the underlying mechanisms remain unclear. We combined network toxicology, molecular docking, and in vivo experiments to investigate the role of MTOR-TFEB-regulated autophagy in PS-NP-induced neurotoxicity. Potential targets related to PS-NPs and neurodegenerative diseases were screened from public databases. Enrichment analysis indicated involvement of neurodegenerative and autophagy pathways. Protein–protein interaction and docking simulations prioritized MTOR as a candidate target. Sprague–Dawley rats were gavaged with PS-NPs (0.15 or 1.5 mg/kg) for 60 days. Morris water maze tests showed impaired spatial learning and memory. Western blotting of hippocampal tissues revealed increased p-MTOR/MTOR ratios, decreased total cytoplasmic and nuclear TFEB, reduced lysosomal proteins (LAMP2, CTSD, and CTSB), elevated autophagy markers SQSTM1 and MAP1LC3B-II, and altered apoptosis regulators (BAX up and BCL2 down). Collectively, PS-NPs disrupt the MTOR-TFEB axis, impair lysosomal function and autophagic clearance, and promote apoptosis, leading to neurocognitive deficits. These findings provide mechanistic insights into the MTOR-TFEB axis and highlight it as a candidate pathway warranting further evaluation as a potential intervention target.