Multi-omics analysis reveals oxidative stress-associated alterations in glycerophospholipid metabolism and inflammatory response in 6PPDQ-exposed macrophages.

Abstract

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone (6PPDQ), a transformation product of the tire antioxidant 6PPD, is an emerging environmental contaminant with increasing toxicological concern. While macrophages are critical in recognizing and managing chemical stress, how 6PPDQ exposure perturbs their innate immune functions and intracellular metabolic homeostasis remains largely unexplored. Here, RAW 264.7 macrophages were exposed to 6PPDQ and examined using biochemical assays, integrated transcriptomic and metabolomic analyses, and N-acetylcysteine (NAC)-based antioxidant intervention. Exposure to 6PPDQ caused dose-dependent cellular injury, characterized by increased membrane damage, excessive reactive oxygen species (ROS) accumulation, glutathione depletion, inflammatory mediator upregulation, mitochondrial dysfunction, and enhanced apoptosis. Multi-omics analysis further revealed significant alterations in glycerophospholipid-related metabolic profiles, accompanied by enrichment of TNF and NF-κB inflammatory signaling. Several phospholipid species levels were decreased, whereas the level of lysophosphatidic acid (LPA) and the expression of its related genes Gpat3 and Lpar2 were markedly elevated. Pretreatment with NAC not only suppressed ROS accumulation, but also attenuated both lipid metabolic and inflammatory alterations induced by 6PPDQ. Collectively, these findings suggest that oxidative stress is closely associated with alterations in glycerophospholipid-related metabolic profiles and inflammatory responses during 6PPDQ-induced macrophage injury.