Acot1 is a sensitive indicator for PPARα activation after perfluorooctanoic acid exposure in primary hepatocytes of Sprague-Dawley rats

Effects of PFAS on human liver transporters: implications for health outcomes

Per- and polyfluoroalkyl substances (PFAS) have become internationally recognized over the past three decades as persistent organic pollutants used in the production of various consumer and industrial goods. Research efforts continue to gauge the risk that historically used, and newly produced, PFAS may cause to human health. Numerous studies report toxic effects of PFAS on the human liver as well as increased serum cholesterol levels in adults. A major concern with PFAS, also dubbed "forever chemicals," is that they accumulate in the liver and kidney and persist in serum. The mechanisms responsible for their disposition and excretion in humans are poorly understood. A better understanding of the interaction of PFAS with liver transporters, as it pertains to the disposition of PFAS and other xenobiotics, could provide mechanistic insight into human health effects and guide efforts toward risk assessment of compounds in development. This review summarizes the current state of the literature on the emerging relationships (eg, substrates, inhibitors, modulators of gene expression) between PFAS and specific hepatic transporters. The adaptive and toxicological responses of hepatocytes to PFAS that reveal linkages to pathologies and epidemiological findings are highlighted. The evidence suggests that our understanding of the molecular landscape of PFAS must improve to determine their impact on the expression and function of hepatocyte transporters that play a key role in PFAS or other xenobiotic disposition. From here, we can assess what role these changes may have in documented human health outcomes.

Transcriptome and Metabolome analysis reveal HFPO-TA induced disorders of hepatic glucose and lipid metabolism in rat by interfering with PPAR signaling pathway

PFOA is one of the most representative compounds in the family of perfluorinated organic compounds. Due to its varying toxicity, alternatives to PFOA are beginning to emerge. HFPO-TA is an alternative for PFOA. It is currently unclear whether HFPO-TA affects glucose and lipid metabolism. In this study, rats were used as an animal model to investigate the effects of HFPO-TA on liver glucose and lipid metabolism. We found that HFPO-TA can affect glucose tolerance. Through omics analysis and molecular detection, it was found that HFPO-TA mainly affects the PPAR signaling pathway in the liver of rats, inhibiting liver glycolysis while promoting glucose production. HFPO-TA not only promotes the synthesis of fatty acids in the liver, but also promotes the breakdown of fatty acids, which ultimately leads to the disruption of hepatic glucose and lipid metabolism. The effects of HFPO-TA on metabolism are discussed in this paper to provide a reference for the risk assessment of this PFOA substitute.

Rutin ameliorate PFOA induced renal damage by reducing oxidative stress and improving lipid metabolism

Perfluorooctanoic acid (PFOA) is a persistent environmental pollutant that can accumulate in the kidneys and eventually cause kidney damage. Rutin (RUTIN) is a natural flavonoid with multiple biological activities, and its use in against kidney damage has been widely studied in recent years. It is not yet known whether rutin protects against kidney damage caused by PFOA. In this study, 30 ICR mice were randomly divided into three groups: CTRL group, PFOA group and PFOA+RUTIN group. The mice were fed continuously by gavage for 28 days. Renal pathological changes were assessed by HE and PASM staining, and serum renal function and lipid indicators were measured. RNA-seq and enrichment analysis using GO, KEGG and PPI to detect differential expression of genes in treatment groups. Kidney tissue protein expression was determined by Western blot. Research has shown that rutin can improve glomerular and tubular structural damage, and increase serum CREA, HDL-C levels and decrease LDH, LDL-C levels. The expression of AQP1 and ACOT1 was up-regulated after rutin treatment. Transcriptomic analysis indicated that PFOA and rutin affect the transcriptional expression of genes related to lipid metabolism and oxidative stress, and may affected by PI3K-Akt, PPAR, NRF2/KEAP1 signaling pathways. In conclusion, rutin ameliorated renal damage caused by PFOA exposure, and this protective effect may be exerted by ameliorating oxidative stress and regulating lipid metabolism.

Transcriptome and Metabolome Analyses Reveal Perfluorooctanoic Acid-Induced Kidney Injury by Interfering with PPAR Signaling Pathway

Perfluorooctanoic acid (PFOA) is widely used in aviation science and technology, transportation, electronics, kitchenware, and other household products. It is stable in the environment and has potential nephrotoxicity. To investigate the effect of PFOA exposure during pregnancy on the kidneys of offspring mice, a total of 20 mice at day 0 of gestation were randomly divided into two groups (10 mice in each group), and each group was administered 0.2 mL of PFOA at a dose of 3.5 mg/kg or deionized water by gavage during gestation. The kidney weight, kidney index, histopathological observation, serum biochemistry, transcriptomics, and metabolomics of the kidneys of the 35-day offspring mice were analyzed. In addition, malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) levels in the kidney were measured. Transcriptome analysis results showed that 387 genes were up-regulated and 283 genes were down-regulated compared with the control group. These differentially expressed genes (DEGs) were mainly concentrated in the peroxisome-proliferator-activated receptor (PPAR) signaling pathway and circadian rhythm. Compared with the control group, 64 and 73 metabolites were up- and down-regulated, respectively, in the PFOA group. The altered metabolites were mainly enriched in the biosynthesis of unsaturated fatty acids. PFOA can affect the expression levels of circadian rhythm-related genes in the kidneys of offspring mice, and this change is influenced by the PPAR signaling pathway. PFOA causes oxidative stress in the kidneys, which is responsible for significant changes in metabolites associated with the biosynthesis of unsaturated fatty acids.

PFOA exposure causes variations of Acot1 among tissues in rats, and Acot1 in serum can be potentially used as a sensitive marker for health monitoring

Perfluorooctanoic acid (PFOA) is a type of 8-carbon perfluoroalkyl substances (PFASs) widely used in industrial and domestic products, which now is a persistent organic pollutant (POP) found in the environment. Its structure is similar to fatty acids, which enables it to induce the expression of ACOT genes. To investigate the expression levels of Acot1 in various tissues and organs after exposure to PFOA for 28 days in rats, and to compare the variations of Acot1 expression in different tissues, we sectioned samples and incubated with Acot1 antibody. The results show that the transcription and protein expression levels of Acot1 in the liver and kidney of rats increased significantly. Meanwhile, the transcription and protein expression of Acot1 gene were also detected in testis, muscle, and adipose. The results of immunohistochemistry were also verified by western blot detection, and we detected the transcription of Acot1 gene in these tissues and found that they all increased in varying degrees. In this study, the expression of Acot1 protein in rat serum was detected for the first time, and the expression of Acot1 in rat serum was found to be significantly increased after PFOA exposure. In addition, the expression level of Acot1 in rat organism was found to be higher than that in the control group after 4 days of depuration for 7 days of acute PFOA exposure, and Acot1 protein expression also showed an increase with increasing exposure time, indicating that Acot1 can be used as a sensitive biomarker for health monitoring of PFOA occupational workers or exposed persons.

Interactions of perfluorooctanoic acid with acyl-CoA thioesterase 1 (Acot1)

Perfluorooctanoic acid (PFOA), a typical representative of per- and polyfluoroalkyl substances (PFASs), is a widely utilized persistent organic pollutant (POP) known to induce liver toxicity in laboratory animals and wildlife. Evidence suggests that PFOA interacts with Acyl-CoA thioesterase 1 (Acot1) to modulate levels of β-oxidation. Specifically, PFOA accelerates β-oxidation, while Acot1 is inhibitory. Few studies have investigated the specific relationship between PFOA and Acot1 and the mechanism of their interaction remains unclear. In the following study, purified rat Acot1 protein was synthesized via bacterial recombination and the structural features that facilitate its binding to PFOA were assessed via molecular docking technology. Additionally, through use of circular dichroism spectroscopy (CD) and isothermal titration calorimetry (ITC) we demonstrate that PFOA binds to WT-Acot1 through electrostatic attraction and low strength non-covalent hydrogen bonding at a molar ratio of 1:1. Furthermore, we identify N326 and H373 amino acid residues as key regulators of the binding process. Together, these findings clarify the interaction pattern of PFOA and Acot1 proteins and provide insight into the specific molecular mechanisms that induce PFOA toxicity in humans and animals.

Maternal exposure to perfluorooctanoic acid (PFOA) causes liver toxicity through PPAR-α pathway and lowered histone acetylation in female offspring mice

The study was conducted to investigate the liver toxicity in female offspring mice induced by maternal exposure to perfluorooctanoic acid (PFOA). Fifty pregnant Kunming mice were randomly divided into 5 groups with 10 of each, which were treated with 0.2 mL PFOA solution dissolved with deionized water at 0, 1, 2.5, 5, and 10 mg/kg BW, respectively, from the pregnancy day (PND) 0 to day 17. Female offspring mice were sacrificed to collect serum and liver at postpartum day 21. The results showed that PFOA significantly reduced the body weight at weaning and the survival rate of the female offspring mice (P < 0.01) increased the liver index of the pups (P < 0.01). Meanwhile, PFOA also caused hepatic bleeding, local necrosis, and enlargement of hepatocytes and vacuolization. The levels of serum AST, ALT, SOD, and CAT in PFOA treatment group were upregulated significantly (P < 0.01). The expressions of Acot1, Acox1, and Acsl1 genes were increased significantly (P < 0.01). The expression of PPAR-α gene was decreased significantly (P < 0.01). There was no significant difference in the expression of Cpt1a gene among the 5 groups. HAT activity was reduced significantly and HDAC activity was increased significantly. The expression of anti-acetyl-histone H3 and acetyl-histone H4 was reduced significantly. Thus, our findings indicate that exposure to PFOA during pregnancy affects the growth and development of the pups and causes liver damage, disrupting the secretion of enzymes involved in fatty acid oxidation induced by PPAR-α, leading to liver oxidative stress and a decrease in the degree of histone acetylation. Elevated HDAC may aggravate downstream fatty acid metabolism disorders through PPAR-α.