Di-(2-ethylhexyl)-phthalate exposure impairs placental P-glycoprotein efflux function by reducing protein expression and ATP levels.

Di(2-ethylhexyl)phthalate (DEHP), a widespread environmental plasticizer, is linked to adverse pregnancy outcomes, including congenital heart defects. Placenta forms a critical barrier, with P-glycoprotein (P-gp), an ATP-dependent efflux transporter, serving to protect the fetus from xenobiotics. However, the impact of DEHP on its function remains poorly understood. This study investigates whether DEHP impairs placental P-gp function with the potential mechanism of ATP depletion. In a mouse model and Bewo cell line, DEHP exposure significantly downregulated the predominant placental P-gp isoform (Abcb1b) and reduced total P-gp protein expression. Notably, ATP levels were depleted in both placental tissue and Bewo cells. Functional assays revealed that DEHP increased intracellular accumulation of rhodamine 123 and calcein, indicating impaired P-gp efflux activity. Crucially, MgATP supplementation restored ATP levels and rescued P-gp function, underscoring the essential role of ATP in transporter activity. Mechanistic studies showed that DEHP induced mitochondrial structure damage, reduced NAD⁺/NADH ratio, and increased lactate production, suggesting a metabolic shift toward glycolysis and mitochondrial dysfunction. Our findings reveal that DEHP exposure impair P-gp function through a dual mechanism involving the downregulation of P-gp protein and the ATP depletion. Importantly, the ATP depletion likely constitute a key mechanism underlying DEHP-induced P-gp dysfunction, providing new insights into the environmental disruption of fetal protection.