6PPD-Quinone Promotes Metabolic Dysfunction-Associated Steatotic Liver Disease through Immune-Inflammatory Disruption

Abstract

6PPD-quinone (6PPDQ), a transformation product of the tire antioxidant 6PPD, is widely detected in environmental and human matrices, yet its relevance to metabolic liver disease remains unclear. We examined its potential contribution to metabolic dysfunction-associated steatotic liver disease (MASLD) by integrating disease-burden analysis, computational toxicology, human transcriptomics, and cross-model validation. The intersection of predicted 6PPDQ targets with MASLD transcriptomic signatures identified 103 candidate genes enriched predominantly in immune and inflammatory pathways. Three machine-learning algorithms prioritized six hub genes, ASPM, ERN1, GADD45B, GINS2, LDLR, and MYPOP, which discriminated MASLD from controls with a combined AUC of 0.997. Immune deconvolution and single-cell analyses were associated with this signature with hepatic immune remodeling and intercellular communication. Molecular docking and 100 ns molecular dynamics simulations predicted stable interactions between 6PPDQ and several targets, particularly ERN1. Environmentally informed low-dose oral exposure produced hepatic steatosis, inflammation, and injury in mice, while LC-MS/MS confirmed internal exposure. Concordant transcriptional responses were reproduced in the hiPSC-derived liver organoids. Integration of these findings supported a provisional adverse outcome pathway linking 6PPDQ exposure to MASLD-related liver injuries. Collectively, these results implicate 6PPDQ as a plausible environmental hazard for metabolic liver injury and support expanding the risk assessment of tire-derived contaminants beyond that of aquatic ecotoxicity.