Gestation represents a critical developmental window of fetal vulnerability to xenobiotic-induced disruptions of biological homeostasis. While xenobiotic transfer is primarily studied through maternal-fetal comparisons at delivery, its spatiotemporal distribution across gestation stages, particularly the transport mechanisms in early pregnancy, remains poorly understood. In this study, we reveal spatiotemporal heterogeneity of hydrophobic toxicants (including persistent organic pollutants such as medium-chain chlorinated paraffins [MCCPs] and hexabromocyclododecane) and endogenous metabolites in the developing placenta and fetus by mass spectrometry imaging (MSI). The stage of transition to hemotrophic nutrition is found as a critical window with fetal-to-maternal distribution ratios of xenobiotics approximately 8.4-38.2-times higher than those estimated at birth. At this critical stage, Scavenger Receptor Class B Member 1 (SR-B1) is identified as the key, stage-specific, and predominate transporter mediating fetal delivery of hydrophobic toxicants and lipids in early gestation through integration of spatial metabolomics and single-nucleus RNA sequencing of placental tissue. Finally, our findings demonstrate that early gestational exposure to MCCPs is associated with fetal neuro-lipotoxicity. The results highlight the urgent need to reduce early-pregnancy xenobiotic exposure for preventing toxicant-associated fetal lipid metabolic disruption.

Glucocorticoids (GCs) are emerging endocrine-disrupting chemicals that may threaten aquatic organisms even at ng/L levels. Wastewater treatment plants (WWTPs) therefore serve as a critical barrier preventing GCs from entering the environment. To elucidate their occurrence and fate, we quantified 68 natural and synthetic GCs and performed a mass balance in a WWTP operating an anaerobic-anoxic-aerobic process. In the influent, 36 GCs were detected, with a total dissolved concentration of 4156 ng/L. Sixteen cortisol derived metabolites dominated the natural GC profile (4073 ng/L), whereas cortisol itself was present at only 20 ng/L. Among synthetic GCs, hydrocortisone-type compounds showed the highest concentrations, followed by several less-studied ester analogues. Natural GCs (except 11 alpha-THCRL), hydrocortisone types, betamethasone types and labile prodrug esters were readily removed from the dissolved phase (82%-100%). In contrast, acetonide types (58-90%) and halogenated esters (15-92%) showed higher persistence. Mass balance analysis showed that GCs were removed mainly through biodegradation, with mass losses of 59-100%. Across the treatment train, 0-16% and 0-94% of the initial load were discharged via sludge and effluent. The substantial proportion released with the effluent highlights a major pathway through which GCs enter aquatic environments and potentially exert ecological risks.

Chlorinated paraffins (CPs) cannot be efficiently removed by conventional water treatment processes and are continually discharged into the aqueous environment. Ozonation can effectively remove lipophilic and persistent pollutants. However, the degradation behaviors of short-chain CPs (SCCPs), medium-chain CPs (MCCPs), and long-chain CPs (LCCPs) in wastewater during the ozonation process remained unknown. In this study, ozonation treatment achieved removal efficiencies of 61 % for SCCPs, 66 % for MCCPs, and 51 % for LCCPs from wastewater within 30 min. Approximately 147 oxidative products of SCCPs, MCCPs, and LCCPs were non-targeted identified through Ph4PCl-enhanced ionization with ultra-high performance liquid chromatography-Orbitrap mass spectrometry. These oxidation products were structurally classified into three categories: carbon chain breakage (53 products), HCl-elimination (27 products), and hydroxylation (67 products). Twenty-three di-hydroxylated CPs were newly identified among the products. Hydroxylation was the predominant pathway for SCCPs, producing di-hydroxylated SCCPs ((OH)₂-SCCPs) with a higher generation rate constant (KG = 22.28 × 10⁻² min⁻¹) compared to other products. MCCPs and LCCPs mainly underwent carbon chain breakage and hydroxylation, generating shorter carbon chain congeners, (OH)2-SCCPs, and di-hydroxylated MCCPs ((OH)2-MCCPs). The KG values of (OH)2-SCCPs (10.56 × 10-2 min-1) and (OH)2-MCCPs (12.05 × 10-2 min-1) generated from the MCCPs were the highest, and the KG values of MCCPs (6.49 × 10-2 min-1), SCCPs (6.27 × 10-2 min-1), and (OH)2-SCCPs (4.74 × 10-2 min-1) generated from the LCCPs were higher than those of other products. These results comprehensively clarify the oxidation efficiencies and pathways of CPs during ozonation. Future studies must explore the potential risks associated with the oxidation products.

Isoprene is the most abundant biogenic volatile organic compound (BVOC) and has far-reaching impacts on secondary organic aerosol (SOA) formation globally. Its atmospheric oxidation produces diverse isomeric radicals that drive subsequent chain propagation and mechanistic branching. However, high-throughput experimental characterization of these isomeric-resolved radicals remains unavailable, leaving critical gaps in the underlying molecular mechanisms. Here we establish a radical-omics approach for isomer-specific identification and detection of hundreds of radical species generated during VOCs oxidation. Applied to OH-initiated isoprene oxidation, this method enables experimental quantification of four OH-added allylic radicals and determination of their branching ratios. We further found hydrogen-abstraction to be an unexpectedly important pathway, contributing up to 8.78 ± 3.96% of total branching. Incorporating the updated mechanism into a global chemical transport model shows that this pathway contributes up to 13.5% of isoprene-derived low-volatility SOA over tropical rainforests. These results provide an experimental foundation for radical screening and targeted mechanistic validation, revealing hidden pathways in complex atmospheric conditions.

Carbohydrates with high structural complexity are involved in key biological processes and serve as susceptible targets of environmental metabolic disruptors. However, the lack of a high-throughput and sensitive method for profiling carbohydrates limits our mechanistic understanding of the disruption of sugar metabolic pathways. In this study, we found that postcolumn addition of 10 μM (chloromethyl)triphenylphosphonium chloride (Ph3(CH2Cl)PCl) enabled the efficient ionization of saccharides and sugar alcohols as [M+Cl]- adducts in high-resolution mass spectrometry analysis, lowering instrumental detection limits by an average of 4- to 767-fold. A nontargeted method for polyol-containing compounds (PCCs) was subsequently established by leveraging their characteristic chlorinated isotope patterns. Approximately 68 PCCs, including saccharides with a degree of polymerization of 1-15, sugar alcohols, nonglucosyl saccharides, O-glycosides, nucleosides, amino sugars, a purine base, and a vitamin, were identified from microbially rich samples such as beer and mouse cecal contents. The method successfully identified disrupted saccharides and nucleosides in the cecal contents of mice exposed to a bisphenol A replacement (TGSA). Ph3(CH2Cl)PCl-enhanced ionization was further found to enhance analytical sensitivity and expand the species coverage in mass spectrum imaging, broadening the range of detectable saccharides (e.g., di- and trisaccharides) in biological samples. The imaging method confirmed alterations of PCCs in the central nervous system and liver tissues by medium-chain chlorinated paraffins during fetal development. This study provides an effective tool for the quantification, identification, and imaging of PCCs to screen for environmental disruptors of sugar metabolism.

With the widespread coexistence of multiple food additives, their combined exposure has raised increasing health concerns. This study used high-content imaging to investigate the individual and combined effects of five common food additives on lipid metabolism in HepG2, Caco-2, and Jurkat T cells. In HepG2 and Caco-2 cells, all additives dose-dependently induced lipid and free cholesterol accumulation; by contrast, Jurkat T cells exhibited only sporadic statistical differences without biologically relevant dose-dependent effects. Notably, lipid droplet accumulation appeared as a relatively early and readily detectable response, though its suitability as a definitive biomarker of metabolic disturbance warrants further validation. Combined-exposure experiments, conducted in HepG2 and Caco-2 cells, revealed cell-specific interaction patterns: additive interactions dominated in HepG2 cells, while sodium benzoate and sodium cyclamate showed synergistic disruption in Caco-2 cells. These results provide in vitro evidence that multi-component combined exposure causes cell-specific lipid-related perturbations not fully captured by single-additive assessment, suggesting that mixture toxicity models should be incorporated to improve food safety evaluation.

Chlorinated paraffins (CPs) and environmental persistent free radicals (EPFRs) are classes of emerging organic pollutants with adverse health and environmental impacts. In this study, we investigated the occurrence, sources, environmental determinants, and health risks associated with CPs and EPFRs in PM2.5 collected from Shijiazhuang, China. The results demonstrated the ubiquity of both CPs (primarily SCCPs and MCCPs) and EPFRs in PM2.5, with concentrations ranging from 3.48 × 102 to 3.89 × 103 pg/m3 and from 1.03 × 1012 to 6.11 × 1013 spins/m3, respectively. Source apportionment revealed that CPs primarily originated from CP-related products, industrial emissions, and vehicular emissions, whereas EPFRs were mainly attributed to atmospheric oxidation and vehicle emissions. The concentrations of CPs and EPFRs were positively associated with PM10, CO, and NO2 and negatively associated with relative humidity. Health risk assessments indicated that children (<6 years) and adults (≥18 years) exhibited higher inhalation exposure levels to both CPs and EPFRs. Notably, individuals aged 18-59 years showed the highest cigarette equivalent inhalation exposure to EPFRs, with average values of 0.285 (head airway), 0.030 (tracheobronchial region), and 0.063 (alveolar region). These findings provide valuable scientific insights for formulating targeted control strategies and public health interventions to mitigate the health risk of these pollutants globally.

Retinoid X receptor α (RXRα), a central nuclear receptor that heterodimerizes with nearly one-third of vertebrate nuclear receptors, plays a key role in integrating multiple endocrine signaling pathways. However, the vast majority of chemicals are introduced into commercial circulation without undergoing evaluation of their RXRα activity, and the identification of RXRα-active chemicals is challenging relying solely on existing approaches such as effect-directed analysis (EDA). In this study, we assessed RXRα activities in three types of aquatic environments, including source water, surface water, and municipal wastewater effluents, from the Yangtze and Yellow River basins in China. Among the 78 collected samples, 76 samples (97.4 %) exhibited measurable RXRα antagonistic activity. Using RXRα protein-selection mass spectrometry, fourteen compounds were identified as RXRα antagonists, which, to the best of our knowledge, have not been previously reported in the ToxCast database, and flunixin displayed the strongest antagonistic activity with half maximal inhibitory concentration (IC50) values of 14.3 μmol/L, followed by niclosamide (22.2 μmol/L), octabenzone (37.6 μmol/L), tributyl citrate (41.1 μmol/L), perfluorooctanesulfonic acid (43.2 μmol/L), pyraclostrobin (44.5 μmol/L), and buprofezin (68.5 μmol/L). A risk index integrating environmental concentrations and Toxicological Priority Index (ToxPi) scores was subsequently applied to prioritize these RXRα-antagonistic pollutants. Octabenzone and telmisartan consistently ranked among the top two in both source water and surface water samples, showing their relatively high ecological risks and potential concern for human health. These findings offer important evidence to support data-based policymaking, facilitating the targeted management of high-risk contaminants to safeguard both aquatic ecosystems and human health.

Gestational diabetes mellitus (GDM) poses significant risks to both maternal and child health, and its rising incidence necessitates exploration of environmental risk factors. In GDM development, the role of environmental risk factors such as phthalates, a ubiquitous class of endocrine-disrupting chemicals, is not well understood. In this study, we integrated epidemiological and toxicological studies to explore the association between phthalates exposure and GDM risk. We detected ten major phthalates metabolites in serum samples from a GDM case-control cohort and found that the levels of Monobutyl phthalate (MBP), Monoethylhexyl phthalate (MEHP), Monoethyl phthalate (MEP), and Monobenzyl phthalate (MBzP) were significantly elevated in GDM patients compared to healthy controls. By establishing human liver organoids model and high-content imaging method, we demonstrated that MEHP and MBP (2, 10, and 50 μM) enhanced glucose uptake and lipid accumulation in a dose-dependent manner, promoted glycolysis, and altered key metabolic pathways related to insulin resistance. RNA sequencing and pathway analysis revealed that both MEHP and MBP (100 μM) selectively upregulated glycolysis-associated genes while suppressing other glucose metabolism pathways, such as the Tricarboxylic acid cycle and Pentose phosphate pathway, leading to increased pyruvate catabolism and lactate accumulation. Furthermore, liver organoids exhibited greater sensitivity to glucose metabolic disruption in response to MEHP than HepG2 cells, highlighting their suitability as a model for studying phthalates-induced hepatotoxicity. Our study provides novel evidence linking phthalate exposure to GDM risk and elucidates the underlying mechanisms through which phthalates disrupt hepatic metabolism.

Metabolic dysfunction-associated steatotic liver disease (MASLD) has emerged as the most prevalent chronic liver disease worldwide with increasing evidence implicating environmental factors in its development. Although thyroid hormone receptor β (TRβ) plays a pivotal role in MASLD progression, few TRβ disruptors are known due to the receptor's high structural specificity for ligands. In this study, we established a TRβ protein-affinity guided nontargeted identification method and applied it to water samples from the Yangtze and Yellow Rivers, identifying 11 novel TRβ antagonists (IC50: 5.58-80.00 μM). Among them, the insecticide chlorantraniliprole (CAP) emerged as the most potent TRβ antagonist with the highest bioanalytical equivalent concentration, and its effective serum concentrations in mice were even lower than some reported human serum levels. Mechanically, CAP suppressed triiodothyronine (T3)-TRβ-mediated triglyceride assembly and cholesterol metabolism, leading to significant lipid accumulation in liver. Simultaneously, CAP interfered with thyroid TRβ signaling and inhibited thyroid hormone synthesis, resulting in systemic thyroid hormone deficiency that further exacerbated hepatic TRβ antagonism. This reciprocal disruption of the liver-thyroid crosstalk reinforced metabolic imbalance and promoted MASLD development in mice. These preclinical and environmental findings establish TRβ as a plausible molecular target of environmental exposures, warranting human studies to validate the clinical relevance of CAP.

Chlorinated paraffins (CPs) are a group of persistent organic pollutants widely applied in industrial processes, raising significant concerns regarding human internal exposure through environmental and dietary pathways. Currently, there is a lack of effective and cost-efficient methods for extracting CPs from large-scale human biomonitoring samples, and short-term variations in human internal exposure remain insufficiently characterized, particularly among the vulnerable elderly population. Here a novel, rapid, and highly efficient pretreatment method was developed to simultaneously quantify CPs of varying carbon chain lengths in minimized volumes of human plasma. This method significantly reduced the required sample volume and streamlined operational steps. It also minimized matrix effects while maintaining high accuracy and precision, enabling the simultaneous extraction of 13 very-short-chain chlorinated paraffins (vSCCPs), 24 short-chain chlorinated paraffins (SCCPs), 34 medium-chain chlorinated paraffins (MCCPs), and 35 long-chain chlorinated paraffins (LCCPs) from limited plasma samples (50 μL). The method detection limits (MDLs) and method quantification limits (MQLs) ranged from 0.02 to 1.80 ng/mL and 0.06-7.21 ng/mL, respectively. Using this method, we assessed temporal variability in internal CPs exposure across 315 plasma samples collected over 5 consecutive months from 76 healthy elderly individuals (aged 60-69) in Jinan, China. The detection frequencies were highest for SCCPs (98.73 %) and vSCCPs (90.48 %), followed by MCCPs (31.75 %) and LCCPs (16.83 %). Mean plasma concentrations were 6.12 ng/mL for SCCPs, 0.91 ng/mL for vSCCPs, 0.33 ng/mL for MCCPs, and 0.04 ng/mL for LCCPs, with a declining trend observed for vSCCPs and SCCPs over time. Correlation analysis and linear mixed-effects models (LMM) suggested that diet was the primary exposure pathway for CPs, with indoor hygiene practices also showing associations. This study provides a significant methodological advancement for biomonitoring CPs exposures, offering a powerful tool for characterizing exposure dynamics and providing a groundwork for mitigating health risks associated with these persistent pollutants globally.

Endogenous antimicrobial peptides and proteins are essential for shaping and maintaining a healthy gut microbiota, contributing to anti-inflammatory responses and resistance to pathogen colonization. Salmonella enterica subsp. enterica serovar Typhimurium (ST) infection is one of the most frequently reported bacterial diseases worldwide. Manipulation of the gut microbiota through exogenous antimicrobial peptides may protect against ST colonization and improve clinical outcomes. This study demonstrated that oral administration of the antimicrobial peptide AP2 (2 µg /mouse), an optimized version of native apidaecin IB (AP IB), provided protective effects against ST infection in mice. These effects were evidenced by reduced ST-induced body weight loss and lower levels of serum inflammatory cytokines. A 16 S rRNA-based analysis of the cecal microbiota revealed that AP2 significantly modulated the gut microbiota, increasing the relative abundance of Bifidobacterium while decreasing that of Akkermansia at the genus level. Furthermore, the transplantation of fecal microbiota from AP2-treated donor mice, rather than from Control mice, significantly reduced cecal damage caused by ST and decreased the concentration of ST by one order of magnitude after infection. These findings reveal a novel mechanism by which exogenous antimicrobial peptides mitigate Salmonella Typhimurium infection through the modulation of gut microbiota.

The objective of this study was to evaluate the effects of cage size on the natural behavior, serum biochemistry, production performance and hypothalamic transcriptome profiles of laying hens. A total of 360 79-week-old hens were selected and randomly assigned to three groups (with five replicates each) with different cage sizes: large cages (LCs), medium cages (MCs), and small cages (SCs). The stocking density remained consistent across all groups throughout the experimental period. Behavioral expression was evaluated through observation of only six birds per group on a weekly basis. Compared to the SC group, the average frequencies of walking, wing-flapping, feather-pecking and drinking significantly increased in the LC and MC groups (P <0.05), whereas the average frequency of stereotypic behavior significantly decreased (P <0.05), indicating that cage size has positive effects on natural behavior. The average daily step count (DSC) was in the order LC > MC > SC (P <0.05), which suggested an improvement in exercise ability in larger cages. The serum levels of MDA, CORT, AST and T-CH were significantly lower in the LC and MC groups than in the SC group (P <0.05), whereas the serum activities of SOD and GSH-Px were significantly greater (P <0.05). Additionally, compared to the SC group, the laying rates were increased by 1.61% and 2.20% (P <0.05), and the feed conversion ratio (FCR) were improved by 1.35% and 2.25%, respectively (P <0.05) in the LC and MC groups, respectively. In total, 437 and 81 differentially expressed genes (DEGs) were identified in the hypothalamus of birds between the LC and SC groups and the MC and SC groups, respectively. A majority of these DEGs were involved primarily in neuroactive ligand‒receptor interactions, focal adhesion and calcium signaling pathways, which are associated with the regulation of behavioral patterns, the stress response and follicular development. Our results suggest that an appropriate increase in cage size is beneficial to the natural behavior expression, health status and production performance of laying hens.

Traditional Chinese Medicine (TCM), such as artemisinin, berberine and proanthocyanidin, has been considered an effective additive for broiler production. High density farming (HDF), which is the primary modern mode of chicken production, is associated with animal health problems. This work aimed to evaluate the effects of dietary TCMs (dihydroartemisinin, hydrochloride, and oligomeric proanthocyanidins) on improving the antioxidant capacity of chickens under HDF and their underlying mechanisms. A total of 360 Wuding chickens (134-day-old) were divided into five experimental groups: one normal stocking density (8 birds/m2, control group) and four high stocking density (16 birds/m2), with six replicates for each group. For four HDF groups, one group was fed the basal diet, and the other three groups were fed the basal diet supplemented with 80 mg/kg dihydroartemisinin, 600 mg/kg berberine hydrochloride, and 250 mg/kg grape oligomeric proanthocyanidins, respectively. HDF increased malondialadehyde level, but decreased superoxide dismutase, glutathione and glutathione peroxidase levels in the liver of broiler; however, dietary TCMs apparently alleviated this attenuation. Dietary TCMs significantly decreased the expression of genes involved in cholesterol synthesis in the liver and the levels of tripepides in the intestine of the HDF chickens. Meanwhile, dietary TCMs significantly altered the composition of the liver microbiome in the HDF chickens, expressing by reduced Pseudomonas but enriched Bradyrhizobium. The gut microbiota of the HDF chickens was also altered following dietary TCM administration, with a decreased abundance of Microbacter margulisiae and an increased abundance of acetate synthesis genes. Association analysis of the multi-omics results revealed negative correlations between liver cholesterol synthesis and antioxidant factors that could be regulated by gut microbiota-produced short-chain fatty acids. Furthermore, alleviating of oxidative stress by dietary TCMs also showed significant correlations with the liver microbiome, which could be mediated by tripeptides produced by the gut microbiota. These results indicated that dietary TCM is beneficial in improving antioxidant defenses in HDF chickens and interpreted the mechanisms of action of TCM from the perspective of modern science.

The considerable variability in bioaccumulation factors (BAFs) of per- and polyfluoroalkyl substances (PFAS) across aquatic species, driven by the diversity of PFAS, complex water conditions, and species differences, underscores the resource-intensive nature of relying on experimental data. To develop a robust and effective approach for predicting BAFs, a predictive framework using a three-level stacking deep ensemble learning model was established. Initially, we compiled a substantial dataset of BAFs, encompassing a wide variety of PFAS across both marine and freshwater species. The stacking model demonstrated strong performance, achieving R-squared (R2) values of 0.94 and 0.89, and root-mean-square errors (RMSE) of 0.88 and 1.17 for training and testing, respectively. External validation revealed that 60 % and 90 % of predictions fell within 2-fold and 4-fold differences, respectively, from the observed values. Using this model, we predicted BAFs for 4950 PFAS in 54 global edible fish species, with the predicted median BAF values ranging from 22 L/kg to 477.09 L/kg. The results indicated that PFAS with multiple functional groups (e.g., benzene rings and ketones) exhibited higher BAFs. Finally, an accessible online tool (https://pfasbaf.hhra.net/) was launched to facilitate BAF predictions. This newly released application promises to offer valuable support for environmental risk management and policymaking efforts.

Short-chain chlorinated paraffins (SCCPs) are a complex mixture of chlorinated derivatives of n-alkanes with a chain length of 10-13 carbon atoms. SCCPs have been extensively used in industrial applications, although an alarming concern is increasingly raised in hazarding environmental matrices and biological organisms due to the environmental persistence, bioaccumulation potential, biotoxicity, and long-range atmospheric transport. Herein, this study conducted a critical review of human internal exposure to SCCPs and its concerning health risks by thoroughly analyzing 63 relevant articles screened in online databases, including the Web of Science, PubMed, Elsevier ScienceDirect, and China National Knowledge Infrastructure (CNKI). The review focused on various biological matrices, including blood, breast milk, and placenta, to assess human internal exposure to SCCPs, and summarized systematic health risk assessments for external exposures across different population groups. The primary exposure routes of SCCPs were dietary intake and dust ingestion and dermal absorption. Particularly, vulnerable population groups of infants, children, and occupational workers suffered from an elevated health risk of SCCPs, with the daily SCCPs intake approaching or exceeding the tolerable daily intake (TDI). So far, existing literature on an internal exposure to SCCPs by detecting human biological samples is insufficient and lacks a comprehensive, life cycle-wide monitoring of vulnerable and occupational populations. The relationship between human exposure to SCCPs and the consequent adverse health effects requires a further deep mining. Moreover, there is a lack of established exposure warning guidance values, and available internal exposure assessment models of SCCPs are currently limited. The future research priority is to knit together the assessment of human internal exposure to SCCPs and the following health risk by advanced sample pre-treatment and analytical methodologies, standardized operating procedures, and non-targeted screening combined with targeted detection techniques. Through a continuous monitoring of human internal exposure to SCCPs, clear illustration of the exposure-effect relationship and comprehensive health risk assessments via multiple exposure routes, these results shed lights on developing and revising regulatory frameworks for governing the production and handling of SCCPs.

Phthalate esters (PAEs) and per- and polyfluoroalkyl substances (PFAS) are ubiquitous pollutants tied to metabolic and immune disorders. The peroxisome proliferator-activated receptor (PPAR) pathway has been indicated to mediate their toxic effects, but the specific functions of PPAR subtypes and their mediating roles remain unclear. In this study, we generated PPARα-, δ-, and γ-specific knockout THP-1 cell lines by using CRISPR/Cas9 system and then differentiated them into interleukin-4 (IL-4) and interleukin-13 (IL-13)-polarized macrophages (alternative activation). During the induction process, the cells were exposed to 0, 6.25, 12.5, 25, 50, 100 μM of five PAE metabolites: Mono-(2-ethylhexyl) phthalate (MEHP), Monocyclohexyl phthalate (MCHP), Monoisonyl phthalate (MINP), Monoisobutyl phthalate (MIBP), and Monobenzyl phthalate (MBzP); and five PFAS: Perfluoroundecanoic acid (PFUnDA), Perfluorodecanoic acid (PFDA), Perfluorooctanoic acid (PFOA), Potassium perfluorooctanesulfonate (PFOS-K), and Potassium 9-chlorohexadecafluoro-3-oxanonane-1-sulfonate (F53B) for 48 h. The results showed that PPARδ deletion abolished CD209 expression, confirming its essential role, whereas PPARα deletion reduced and PPARγ deletion enhanced CD209, indicating PPARα promotes and PPARγ restrains alternative activation. Compounds displayed subtype-selective actions: MEHP activated PPARα/γ; MBzP/MCHP inhibited PPARδ yet activated PPARγ; MINP activated PPARγ only. Among PFAS, PFOS-K activated PPARδ/γ; F53B inhibited PPARα; PFOA activated PPARγ; PFDA inhibited PPARα/δ. Transcriptomics revealed compound-specific enrichments-cholesterol (MEHP), fatty-acid (MCHP), glycolysis (PFOS-K), TCA cycle (PFOA)-despite common PPAR pathway engagement. In conclusion, PAEs and PFAS disrupt macrophage plasticity through distinct PPAR-subtype signatures, providing molecular landmarks for future hazard assessment of environmental pollutants.

BACKGROUND:Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common liver disease worldwide, and increasing evidence suggests that exposure to environmental pollutants is associated with the increased incidence of MASLD. The farnesoid X receptor (FXR) plays an important role in the development of MASLD by regulating bile acids (BAs) and lipid metabolism. However, whether FXR-active pollutants are the environmental drivers of MASLD remains unclear. OBJECTIVES:This study aimed to determine whether FXR-active pollutants exist in the environment and evaluate their ability to trigger MASLD development in mice. METHODS:An FXR protein affinity pull-down assay and nontargeted mass spectrometry (MS) analysis were used to identify environmental FXR ligands in sewage sludge. A homogeneous time-resolved fluorescence coactivator recruitment assay and cell-based dual-luciferase reporter assay were used to determine the FXR activities of the identified pollutants. Targeted analysis of BAs, MS imaging, lipidomic analysis, 16S rRNA sequencing, and quantitative polymerase chain reaction were conducted to assess the ability of FXR-active pollutants to induce metabolic disorders of BAs and lipids and to contribute to MASLD development in C57BL/6N mice. RESULTS:We identified 19 compounds in the sewage sludge that had FXR-antagonistic activity, and triphenyl phosphate (TPHP) was the FXR antagonist with the highest efficacy. Mice exposed to either 10 or 50mg/kg TPHP for 30 d had higher levels of conjugated primary BAs in enterohepatic circulation, and the BA pool showed FXR antagonistic activities. The exposed mice also had greater lipogenesis (more Oil Red O staining and high triglyceride levels) in liver. CONCLUSIONS:Nineteen FXR-antagonistic pollutants were identified in sewage sludge. FXR inhibition by the strongest antagonist TPHP may have a role in promoting MASLD development in mice by inducing a positive feedback loop between the FXR and BAs. https://doi.org/10.1289/EHP15435.

Per- and polyfluoroalkyl substances (PFAS) are pervasive environmental pollutants with diverse toxic effects (e.g., hepatotoxicity and metabolism disorder). Macrophages played a key role in metabolic response; however, the effect of macrophage on PFAS-induced toxicity and the underlying mechanisms remain poorly understood. In this study, we constructed a high-content cell model by utilizing the activation and differentiation of human THP-1 monocytes into alternative activation of macrophages, enabling rapid quantitative screening of numerous PFAS. We applied the cell model to screen 10 PFASs and identified that PFOA and PFUnDA significantly suppressed alternative activation of macrophages by disrupting the PPAR signaling pathway. Oral exposure to PFOA and PFUnDA in WT mice also significantly impaired alternative activation of macrophages in the liver and induced hepatocyte hypertrophy, liver dysfunction, and systemic lipid metabolism disorders. Moreover, macrophage-specific knockout of PPARγ exacerbated PFOA and PFUnDA-induced suppression of macrophage alternative activation and subsequent hepatotoxicity. Activation balance between PPARα and PPARγ may be a critical factor by PFOA and PFUnDA to affect the alternative activation of macrophage. These findings highlight the immunometabolism regulatory role of macrophage activation in PFAS-induced hepatotoxicity in humans.

Metabolism-disrupting chemicals (MDCs) have attracted widespread attention due to their contributions to the prevalence of metabolic diseases worldwide. The farnesoid X receptor (FXR) is a typical lipid-sensing nuclear receptor and plays a crucial role in the development of metabolic diseases. However, few studies have examined the FXR activities of environmental samples and the corresponding MDCs. In this study, we found FXR-antagonistic activities in 93.6% of source water, surface water, and wastewater samples (n = 78) collected from the Yangtze River and Yellow River. An FXR protein-affinity guided nontargeted analysis was performed and identified 79 potential FXR-active pollutants in samples from these two rivers. Nine of these pollutants exhibited strong FXR-antagonistic activities (IC50: 2.39-141.9 μM), and 6 pollutants, including triphenyl phosphate (TPHP), 4,4'-sulfonylbis[2-(2-propenyl) phenol (TGSA), tonalid (AHTN), dichlorophen, etoxazole (ETX), and loratadine, were identified to be FXR antagonists for the first time. The total concentrations of the nine FXR-antagonistic pollutants were relatively high in the middle and downstream reaches of the Yellow River and the downstream reaches of the Yangtze River, and two pollutants (TGSA and ETX) have not previously been found in aquatic environments. A risk prioritization analysis revealed that TPHP, TGSA, and AHTN are priority pollutants with the potential to affect the FXR. Appropriate management of these priority pollutants would reduce the health risks of metabolic disruptions associated with exposure to these MDCs.