Integrative epidemiological and experimental evidence implicates CCNA2-associated macrophage-hepatocyte crosstalk in...

Non-alcoholic fatty liver disease (NAFLD) is a prevalent metabolic disorder in which environmental exposures may play an important role. Dimethyl phosphate (DMP), a major dialkyl phosphate metabolite of organophosphorus pesticides, has traditionally been regarded primarily as a biomarker of exposure, whereas its potential biological role in NAFLD remains largely unexplored. In this study, we investigated whether DMP may exert biologically relevant effects in NAFLD progression and explored the underlying molecular mechanisms. Epidemiological analysis of 3050 participants from the National Health and Nutrition Examination Survey (NHANES) demonstrated a significant association between urinary DMP levels and NAFLD prevalence. Integrative bioinformatic analysis identified 24 DMP-NAFLD-related genes, among which six key NAFLD-associated genes were further prioritized, including four positively correlated genes (AURKA, CCNA2, WFDC2, and UBE2C) and two negatively correlated genes (NARS1 and SRSF3). These genes were subsequently incorporated into a diagnostic nomogram that exhibited good discriminative performance (AUC = 0.848). Connectivity mapping combined with exploratory molecular docking analyses further identified Pictilisib as a potential therapeutic candidate for DMP-induced NAFLD, with CCNA2 predicted to function as a key downstream target. In mice, DMP exposure induced hepatic steatosis, lipid accumulation, and metabolic dysfunction, which were partially attenuated by Pictilisib and genetic knockdown of CCNA2. Mechanistically, DMP increased CCNA2 expression and promoted a pro-inflammatory macrophage phenotype, as indicated by enhanced M1-like polarization and cytokine secretion. These effects were markedly attenuated by CCNA2 silencing, whereas re-expression of CCNA2 substantially restored the phenotype. In addition, conditioned medium from DMP-exposed macrophages induced lipid accumulation in hepatocytes through paracrine signaling. This effect was alleviated by CCNA2 silencing and restored by CCNA2 re-expression. These findings suggest that DMP may exert biological effects beyond its conventional role as an exposure biomarker and may contribute to NAFLD-related pathological processes, potentially through CCNA2-mediated macrophage-hepatocyte interactions.