DEHP disrupts lipid metabolism via autophagy hyperactivation and mitochondrial dysfunction

Di(2-ethylhexyl) phthalate (DEHP) is a widely used industrial plasticizer, raising global concerns due to its potential endocrine-disrupting effects and environmental persistence. Human exposure to DEHP primarily occurs through the ingestion of contaminated food and water, inhalation of airborne particles, and dermal contact with products containing DEHP. Understanding the toxicological mechanisms of DEHP is essential for evaluating its health risks and developing effective strategies to mitigate its adverse effects. In this study, we conducted long-term exposure experiments to DEHP using both an animal model and in vitro system to investigate the complex interplay among DNA methylation, hyperactivation of macroautophagy/autophagy, mitochondrial dysfunction, and lipid accumulation induced by DEHP. The results revealed that DEHP exposure induced the degradation of DNMT1 (DNA methyltransferase 1) by enhancing its interaction with the autophagy-related protein SQSTM1 (sequestosome 1). DNMT1 degradation resulted in decreased methylation of the promoter regions of genes associated with autophagosome formation, subsequently increasing their expression. The resulting demethylation excessively activated autophagy, contributing to mitochondrial dysfunction and lipid accumulation in the liver. This study uncovered a previously unrecognized interplay among hyperactivation of autophagy, mitochondrial dysfunction, and lipid accumulation in the context of DEHP exposure. These findings enhanced our understanding of DEHP's toxicity and underscored concerns about the long-term health effects of environmental pollutants, particularly regarding metabolic diseases.Abbreviation: ATG5:autophagy related 5; ATG16L1: autophagy related 16 like 1; BECN1:beclin 1; COX4/COXIV: cytochrome c oxidase subunit 4; BS-seq:bisulfite sequencing; DCFH-DA: 2',7'-dichlorodihydrofluoresceindiacetate; DEHP: di(2-ethylhexyl) phthalate; DNMT1: DNAmethyltransferase 1; DNMT3A: DNA methyltransferase 3A; FABP4: fattyacid binding protein 4; FASN: fatty acid synthase; LPL: lipoproteinlipase; MAP1LC3/LC3: microtubule associated protein1 light chain 3; NAFLD: nonalcoholic fatty liver disease; NR1H3:nuclear receptor subfamily 1 group H member 3; PPARG: peroxisomeproliferator activated receptor gamma; RB1CC1: RB1 induciblecoiled-coil 1; SQSTM1: sequestosome 1; SREBF2: sterol regulatoryelement binding transcription factor 2; VDAC1: voltage dependentanion channel 1.