Digestive-transformed titanium dioxide nanoparticles disrupt intestinal barrier via mitoxyperilysis mediated by mTOR-cytoskeleton axis dysregulation

Titanium dioxide nanoparticles (TiO2 NPs) are ubiquitous dietary additives, yet their impact on the intestinal barrier remains contentious, largely because conventional toxicological models overlook gastrointestinal digestive transformations. Characterization revealed that pristine TiO2 NPs exist as nanoscale aggregates, which, upon simulated digestion, lose electrostatic repulsion and expand into dense, biocorona-coated, micrometer-sized agglomerates enriched in nitrogen and phosphorus. While these transformed entities induce severe barrier dysfunction, the spatiotemporal mechanisms executing plasma membrane rupture remain a critical knowledge gap in nanotoxicology. Here, we uncover a non-canonical, spatially dependent cell death modality termed mitoxyperilysis as the core driver of TiO2 NPs-induced nanotoxicity, operating independently of classical apoptosis, ferroptosis, necroptosis, and pyroptosis. We demonstrate that exposure to digested TiO2 NPs agglomerates hyperactivates the protein kinase B (AKT)/mechanistic target of rapamycin complex 2 (mTORC2)-RhoA signaling axis, leading to widespread F-actin cytoskeletal paralysis. This structural breakdown dismantles intracellular spatial constraints, enabling ROS-emitting, dysfunctional mitochondria to aberrantly translocate and persistently tether to the plasma membrane, deploying high concentrations of mitochondria-derived ROS (mtROS) locally. Quantitative lipidomics of plasma membrane fractions reveals that this targeted mtROS assault induces severe depletion of membrane-stabilizing lipids and the explosive generation of oxidized lipid mediators, culminating in lytic membrane failure. Ultimately, this nanotoxicology study decodes a novel nano-mechanopathological paradigm dictated by mTOR-cytoskeleton dysregulation and localized mitochondrial lipid peroxidation, providing critical translational insights and therapeutic targets for mitigation.