Potential targets and mechanisms of Di(2-ethylhexyl) phthalate exposure in inducing chronic kidney disease: a multimodal study integrating epidemiology, network toxicology, and Mendelian randomization.

Di(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer present in numerous consumer and medical products and has been associated with adverse effects in multiple organ systems, including the kidney. Chronic kidney disease (CKD) is an increasing global health burden, yet the molecular targets potentially linking DEHP exposure to CKD remain incompletely understood. This study integrated epidemiological analysis, network toxicology, Mendelian randomization (MR), molecular docking, and molecular dynamics simulations to investigate potential molecular targets associated with DEHP exposure and CKD. Data from the National Health and Nutrition Examination Survey (NHANES) were used to examine the association between urinary DEHP metabolites and CKD. DEHP-related and CKD-related targets were subsequently integrated to identify shared targets, followed by PPI network analysis and expression-based evaluation to prioritize candidate genes. MR analysis was then performed to assess the association between genetically proxied candidate genes and CKD. Molecular docking was used to explore the potential interactions between DEHP and the prioritized proteins, and molecular dynamics simulations were performed to further evaluate the structural stability of the predicted DEHP-CTSK complex. Higher urinary DEHP metabolite levels were associated with a higher prevalence of CKD. Four candidate genes-CTSK, ABL1, BCL2L1, and CCND1-were prioritized based on network and expression-based analyses. Among these genes, genetically proxied CTSK showed a significant positive association with CKD in the primary MR analysis. Molecular docking showed favorable predicted docking scores for DEHP with the four candidate proteins, while molecular dynamics simulations supported the structural stability of the predicted DEHP-CTSK complex over 100 ns. These findings provide convergent epidemiological, genetic, and computational evidence supporting CTSK as a candidate molecular target for further investigation in the context of DEHP-associated renal injury.