PFO5DoDA disrupts hepatic homeostasis primarily through glucocorticoid signaling inhibition

Multi-omics analysis reveals BPF exposure causes hepatic glucose and lipid metabolism disorder in rats by disrupting energy homeostasis

Bisphenol F (BPF) is one of the main substitutes for Bisphenol A (BPA) and is widely used in the manufacture of household products. In addition, BPF threatens human health through environmental pollution and the food chain. However, the hepatotoxicity of BPF and its effects on glucose and lipid metabolism remain unclear. This study used male SD rats as an animal model to investigate the hepatotoxicity of BPF and its effects on glucose and lipid metabolism. The results of the HE staining, serum and liver biochemical indicators show that BPF can damage the basic structure of the liver, cause liver dysfunction and lead to disorders of liver glucose metabolism and lipid metabolism. Furthermore, we conducted metabolomics and proteomics analyses on the livers of the BPF exposed group at 100 mg/kg/d in comparison with the control group. The results indicated that BPF exposure had a significant effect on liver metabolism. Combined with biological analysis and the validation of changes in genes and proteins related to glucose and lipid metabolism in the liver, it was elucidated that BPF can promote fatty acid oxidation and inhibit fatty acid synthesis through the AMPK and PPAR signaling pathways, leading to a reduction in fatty acids. Furthermore, it has been demonstrated that BPF can promote glycogen synthesis and gluconeogenesis via the AKT pathway, which can result in disorders of glucose metabolism.

Synthesis and Characterization of a Series of Biofriendly Fluoroether Betaines

Fluoroether approach has been extensively employed as an alternative to conventional fluorinated surfactants; however, it faces challenges such as inadequate performance of short fluoroether chains and environmental contamination from long fluoroether chains. This study aims to address the conflict between environmental compatibility and the performance of fluoroether surfactants. The design of the surfactants is centered around the OC chain (CF3(OCF2)n-), utilizing reduced fluorine content to achieve superior surface activity. A series of surfactant molecules featuring elongated hydrophobic chains and dual-chain structures have been synthesized and characterized. All of the molecules have good surface activity at low concentrations. Among them, CF3(OCF2)4CH2O(CH2)3SO2NH(CH2)3N+(CH3)2CH2COO- (OC4F-B), which employs a strategy of extending the hydrophobic chain by insertion of -CH2O(CH2)3-, shows the best performance. This surfactant can achieve a surface tension of 20 mN/m at a concentration of 0.005 wt %, which is 20 times lower than that required for CF3(OCF2)4CONH(CH2)3N+(CH3)2CH2COO- (OC4-betaine) to attain the same surface tension. In contrast, (CF3(OCF2)3CH2O(CH2)3SO2NHCH2CH2)2N+(CH3)CH2COO- (DOC3F-B), utilizing both dual-chain and extended carbon chain strategies, exhibits a critical micelle concentration that is diminished by 2 orders of magnitude relative to OC3-betaine, reaching to 0.047 g/L. Merely adjusting the length of the fluorocarbon chain is insufficient to reconcile the conflict between the performance and environmental impact of fluorinated surfactants. This study introduces an innovative approach by incorporating hydrocarbon hydrophobic chains and adopting a dual-chain design, thereby addressing this challenge effectively.

Unveiling the Research Void: Exploring the Reproductive Effects of PFAS Compounds on Male Health

Per- and polyfluoroalkyl substances (PFAS) represent an emerging concern for male reproductive health. Epidemiological studies have reported associations between increased PFAS exposure and reduced semen quality parameters, lower sperm counts, and potential alterations in reproductive hormone levels. Toxicology research has revealed possible mechanisms including blood-testis barrier disruption, oxidative stress, interference with testicular cell function, and epigenetic changes. However, significant uncertainties remain regarding definitive exposure-response relationships, developmental windows of heightened vulnerability, combined mixture effects, and causality interpretation, given limitations inherent to observational studies. Ongoing investigation of short-chain and replacement PFAS compounds is also critically needed. Additionally, directly connecting the mechanistic insights from animal models to human fertility impacts remains challenging. While controlled toxicology studies have described pathways by which PFAS could impair cellular functioning in the testes, uncertainty persists in extrapolating these experimental effects to real-world human exposures and sperm parameter declines reported epidemiologically. Overall, current findings suggest PFAS may contribute to declining male reproductive function, but additional clarification through well-designed longitudinal cohort studies integrated with mechanistic animal work is still warranted to confirm exposure-fertility links across a range of PFAS types and inform evidence-based public health mitigation strategies.

Long-chain perfluoroalkylether carboxylic acids PFO5DoA and PFO4DA alter glucose, bile acid, and thyroid hormone homeostasis in fetal rats from 5-day maternal oral exposure

Chemical monitoring studies in North Carolina, USA and Shandong, China have reported detections of perfluoroalkylether carboxylic acids of increasing chain length with ether bonds between each fluorinated carbon. Despite detection there is limited hazard data available to inform risk assessment. Here, we exposed pregnant Sprague-Dawley rats to two of these compounds, perfluoro-3,5,7,9-butaoxadecanoic acid (PFO4DA) and perfluoro-3,5,7,9,11-pentaoxadodecanoic acid (PFO5DoA), from gestation days 18-22 across a series of doses (0.3-62.5 mg/kg/d) via oral gavage. PFO5DoA was acutely toxic to rat dams and fetuses at the top two doses (30 and 62.5 mg/kg), while PFO4DA did not cause acute toxicity at any doses tested. PFO5DoA significantly increased maternal liver weight (≥3 mg/kg; 28% increase at 10 mg/kg) while PFO4DA did not affect maternal liver weight up to 62.5 mg/kg. PFO4DA and PFO5DoA both significantly reduced serum total thyroxine in maternal (≥10 mg/kg for both) and fetal (≥1 mg/kg) rats. Both compounds significantly reduced fetal liver glycogen concentrations, increased fetal serum total bile acids, and altered expression levels of multiple genes associated with glucose metabolism in the fetal liver. Serum concentrations of PFO5DoA were higher than PFO4DA in both rat dams and fetuses at equivalent maternal oral doses indicating greater accumulation. Dose response modelling of several fetal endpoints as a function of serum molar concentration indicates PFO5DoA was ∼3-4-fold more potent than PFO4DA. PFO5DoA and PFO4DA produced maternal and fetal toxicity from short-term oral maternal exposure indicating need for additional toxicity data to evaluate potential human health risks.

Exploring maternal and developmental toxicity of perfluoroalkyl ether acids PFO4DA and PFO5DoA using hepatic transcriptomics and serum metabolomics

Production of per- and polyfluoroalkyl substances (PFAS) has shifted from long-chain perfluoroalkyl acids to short-chain compounds and those with ether bonds in the carbon chain. Next-generation perfluoroalkylether PFAS include HFPO-DA ("GenX chemicals"), Nafion Byproducts, and the PFOx homologous series that includes perfluoro-3,5,7,9-butaoxadecanoic acid (PFO4DA) and perfluoro-3,5,7,9,11-pentaoxadodecanoic acid (PFO5DoA). PFO4DA and PFO5DoA have been detected in serum and/or tissues from humans and wildlife proximal to contamination point sources. However, toxicity data are extremely limited, with no in vivo developmental toxicology data. To address these data gaps, pregnant Sprague-Dawley rats were exposed via oral gavage to vehicle, PFO4DA, or PFO5DoA across a series of doses (0.1 to 62.5 mg/kg/day) from gestation day (GD) 18-22. Hepatic transcriptomics were assayed in dams and fetuses, and serum metabolomics in dams. These data were overlaid with serum PFO4DA and PFO5DoA concentrations to perform dose-response modeling. Both dams and fetuses exhibited dose-responsive disruption of hepatic gene expression in response to PFO4DA or PFO5DoA, with fetal expression disrupted at lower doses than dams. Several differentially expressed genes were upregulated by every dose of PFO5DoA in both maternal and fetal samples, including genes encoding enzymes that hydrolyze acyl-coA to free fatty acids. Maternal serum metabolomics revealed PFO4DA exposure did not induce significant changes at any tested dose, whereas PFO5DoA exposure resulted in dose-dependent differential metabolite abundance for 149 unique metabolites. Multi-omics pathway analyses of integrated maternal liver transcriptomics and serum metabolomics revealed significant convergent changes as low as 3 mg/kg/d PFO4DA and 0.3 mg/kg/d PFO5DoA exposure. Overall, transcriptomic and metabolomic effects of PFO4DA and PFO5DoA appear consistent with other carboxylic acid PFAS, with primary changes related to lipid metabolism, bile acids, cholesterol, and cellular stress. Importantly, PFO5DoA exposure more potently induced changes in maternal and fetal hepatic gene expression and maternal circulating metabolites, despite high structural similarity. Further, we report in vitro PPARα and PPARγ receptor activation for both compounds as putative molecular mechanisms. This work demonstrates the potential developmental toxicity of alternative moiety perfluoroethers and highlights the developing liver as particularly vulnerable to transcriptomic disruption. Synopsis: Developmental exposure to fluoroether carboxylic acids PFO4DA and PFO5DoA result in differential impacts on hepatic transcriptome in dams and offspring and circulating metabolome in dams, with PFO5DoA exhibiting higher potency than PFO4DA.

Single-cell RNA sequencing reveals the heterogeneity of hepatic non-parenchymal cell responses to chronic PFO5DoDA exposure in male mice

Perfluoroalkyl ether carboxylic acids (PFECA) have emerged as novel alternatives to legacy per- and polyfluoroalkyl substances (PFAS). Existing research has revealed hepatoxicity induced by various PFAS, including PFECA. However, these studies have primarily focused on overall changes in whole liver tissue, particularly in hepatocytes, with the impact of PFAS on diverse liver non-parenchymal cells (NPCs) still inadequately understood. In the present study, we examined the heterogeneous responses of hepatic NPCs following exposure to perfluoro-3,5,7,9,11-pentaoxadodecanoic acid (PFO5DoDA), a type of PFECA, by administering PFO5DoDA (5 μg/L)-contaminated water to male mice for one year. Single-cell RNA sequencing (scRNA-seq) of 15 008 cells from the liver identified 10 distinct NPC populations. Notably, although relative liver weight remained largely unchanged following exposure to 5 μg/L PFO5DoDA, there was an observed increase in proliferating cells, indicating that proliferating NPCs may contribute to the hepatomegaly frequently noted in PFAS-exposed livers. There was also a considerable alteration in the composition of hepatic NPCs. Specifically, the total number of B cells decreased substantially, while many other cells, such as monocytes and macrophages, increased after PFO5DoDA exposure. In addition, interactions among the hepatic NPC populations changed variously after PFO5DoDA exposure. The findings emphasize the heterogeneity in the responses of hepatic NPCs to PFO5DoDA exposure. Taken together, the changes in immune cell populations and their intercellular interactions suggest that PFO5DoDA disrupts immune homeostasis in the liver. These findings offer new insights into the cellular mechanisms of PFAS-induced liver damage.

Dietary exposure to per- and polyfluoroalkyl substances: Potential health impacts on human liver

Per- and polyfluoroalkyl substances (PFAS), dubbed "forever chemicals", are widely present in the environment. Environmental contamination and food contact substances are the main sources of PFAS in food, increasing the risk of human dietary exposure. Numerous epidemiological studies have established the link between dietary exposure to PFAS and liver disease. Correspondingly, PFAS induced-hepatotoxicity (e.g., hepatomegaly, cell viability, inflammation, oxidative stress, bile acid metabolism dysregulation and glycolipid metabolism disorder) observed from in vitro models and in vivo rodent studies have been extensively reported. In this review, the pertinent literature of the last 5 years from the Web of Science database was researched. This study summarized the source and fate of PFAS, and reviewed the occurrence of PFAS in food system (natural and processed food). Subsequently, the characteristics of human dietary exposure PFAS (population characteristics, distribution trend, absorption and distribution) were mentioned. Additionally, epidemiologic evidence linking PFAS exposure and liver disease was alluded, and the PFAS-induced hepatotoxicity observed from in vitro models and in vivo rodent studies was comprehensively reviewed. Lastly, we highlighted several critical knowledge gaps and proposed future research directions. This review aims to raise public awareness about food PFAS contamination and its potential risks to human liver health.

Accumulation and glucocorticoid signaling suppression by four emerging perfluoroethercarboxylic acids based on animal exposure and cell testing

Various perfluoroethercarboxylic acids (PFECA) have emerged as next-generation replacements of legacy per- and polyfluoroalkyl substances (PFAS). However, there is a paucity of information regarding their bioaccumulation ability and hazard characterization. Here, we explored the accumulation and hepatotoxicity of four PFECA compounds (HFPO-DA, HFPO-TA, PFO4DA, and PFO5DoDA) in comparison to perfluorooctanoic acid (PFOA) after chronic low-dose exposure in mice. Except for HFPO-DA, the levels of all tested PFAS in the liver exceeded that in serum. High molecular weight PFECA compounds (PFO5DoDA and HFPO-TA) showed stronger accumulation capacity and longer half-lives (t1/2) than low molecular weight PFECA compounds (HFPO-DA and PFO4DA) and even legacy PFOA. Although hepatomegaly is a common apical end point of PFAS exposure, the differentially expressed gene (DEG) profiles in the liver suggested significant differences between PFOA and the four PFECA compounds. Gene enrichment analysis supported a considerable inhibitory effect of PFECA, but not PFOA, on the glucocorticoid receptor (GR) signaling pathway. Both HFPO-TA and PFO5DoDA demonstrated a more pronounced ability to perturb RNA expression profiles in vivo and to suppress GR signaling in vitro compared to HFPO-DA and PFO4DA. Calculated reference doses (RfDs) emphasized the potential hazard of PFECA to human health. Overall, our findings indicate that PFECA alternatives do not ease the concerns raised from legacy PFAS pollution.

Perfluoroalkyl Substances (PFAS) Affect Inflammation in Lung Cells and Tissues

Adverse lung outcomes from exposure to per-and polyfluoroalkyl substances (PFAS) are known; however, the mechanism of action is poorly understood. To explore this, human bronchial epithelial cells were grown and exposed to varied concentrations of short-chain (perfluorobutanoic acid, perflurobutane sulfonic acid and GenX) or long-chain (PFOA and perfluorooctane sulfonic acid (PFOS)) PFAS, alone or in a mixture to identify cytotoxic concentrations. Non-cytotoxic concentrations of PFAS from this experiment were selected to assess NLRP3 inflammasome activation and priming. We found that PFOA and PFOS alone or in a mixture primed and activated the inflammasome compared with vehicle control. Atomic force microscopy showed that PFOA but not PFOS significantly altered the membrane properties of cells. RNA sequencing was performed on the lungs of mice that had consumed PFOA in drinking water for 14 weeks. Wild type (WT), PPARα knock-out (KO) and humanized PPARα (KI) were exposed to PFOA. We found that multiple inflammation- and immune-related genes were affected. Taken together, our study demonstrated that PFAS exposure could alter lung biology in a significant manner and may contribute to asthma/airway hyper-responsiveness.