Dataset Information

Transcriptional profilling of liver from C57BL/6 wildtype and PPARα-knockout mice treated with PFOA and GenX after 20 weeks of high-fat diet

ABSTRACT: Perfluoroalkyl substances (PFAS) are man-made chemicals with suspected endocrine-disrupting properties. Exposure to perfluorooctanoic acid (PFOA) has been linked to disturbed metabolism via the liver, although the exact mechanism is not clear. Moreover, information on the metabolic effects of the new PFAS alternative GenX is limited. We tested whether low-dose exposure to PFOA and GenX induces metabolic disturbances, including NAFLD, dyslipidemia, and glucose tolerance in mice and studied the involvement of PPARα. To this end, male C57BL/6J wildtype and PPARα−/− mice were given 0.05 or 0.3 mg/kg bw/day PFOA, or 0.3 mg/kg bw/day GenX next to a high-fat diet for 20 weeks. RNA sequencing was performed on liver, next to thorough assesment of metabolic parameters. RNA sequencing revealed that whereas the effects of GenX are entirely dependent on PPARα, effects of PFOA are mostly dependent on PPARα. In the absence of PPARα, the involvement of PXR/CAR becomes more prominent. Exposure to high-dose PFOA in mice decreased body weights and increased liver weights in wildtype and PPARα−/− mice. High-dose but not low-dose PFOA reduced plasma triglycerides and cholesterol, which for triglycerides, showed PPARα dependency. PFOA and GenX increased hepatic triglycerides in a PPARα-dependent manner. Overall, we show that long-term and low-dose exposure to PFOA and GenX disrupts lipid metabolism in mice. Whereas the effects of PFOA are mediated by multiple nuclear receptors, effects of GenX are entirely mediated by PPARα. Our data underscore the potential of PFAS to disrupt metabolism by altering signaling pathways in the liver.

ORGANISM(S): Mus musculus

PROVIDER: GSE212294 | GEO | 2022/09/02

REPOSITORIES: GEO

ACCESS DATA

Similar Datasets

Project description:Per- and polyfluoroalkyl substances (PFAS) are some of the most prominent organic contaminants in human blood that have the potential to disrupt biological processes and pathways in the liver. Although the toxicological implications from human exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are well established, data on other, lesser-understood PFAS are limited. A challenge for regulatory authorities is to determine acceptable levels of human exposure to large, diverse classes of environmental contaminants. New approach methodologies (NAMs) that apply bioinformatics tools to interpret biological data are being increasingly considered to inform risk assessment when traditional toxicology methodologies are not amenable. The aim of the current investigation was to identify the biological responses relevant to PFAS mode of action as the concentration (benchmark dose) that these effects take place in order to utililze this information to inform/facilitate read-across for risk assessment of data-poor PFAS. A TempO-Seq platform (BioSpyder) measured gene expression changes in human liver microtissues (i.e., spheroids) after 1-day and 10-day exposures to increasing concentrations of PFAS. A bioinformatics framework was applied to 23 PFAS sub-classed into carboxylates (PFCAs), sulfonates (PFSAs), or PFAS precursors that were analyzed for the total altered transcripts, the concentration where effects take place, and identifying target genes of interest. Both PFCAs and PFSAs exhibited a trend toward increased transcriptional changes with carbon chain-length. Specifically, longer-chain compounds (7 to 10 carbons) were more likely to surpass liver-toxic transcriptomic thresholds established from previous studies than shorter chain PFAS. Longer-chain PFAS were also more potent, inducing transcriptional effects at lower concentrations. However, PFOS was the most potent PFAS and of all precursors, only PFOSA (a PFOS precursor) induced a response. The combined high-throughput transcriptomic and bioinformatics analyses revealed the capability of NAMs to assess the effects of PFAS in liver microtissues; such data improves our understanding of PFAS-related effects in humans and facilitates the use of read-across in human health risk assessment for other data-poor chemicals.

Project description:Perfluorooctane sulfonate (PFOS) is a perfluoroalkyl acid (PFAA) and a persistent environmental contaminant found in the tissues of humans and wildlife. Although blood levels of PFOS have begun to decline, health concerns remain because of the long half-life of PFOS in humans. Like other PFAAs, such as perfluorooctanoic acid (PFOA), PFOS is an activator of peroxisome proliferator-activated receptor-alpha (PPARα) and exhibits hepatocarcinogenic potential in rodents. PFOS is also a developmental toxicant in rodents where, unlike PFOA, it’s mode of action is independent of PPARα. Wild-type (WT) and PPARα-null (Null) mice were dosed with 0, 3, or 10 mg/kg/day PFOS for 7 days. Animals were euthanized, livers weighed, and liver samples collected for histology and preparation of total RNA. Gene profiling was conducted using Affymetrix 430_2 microarrays. In WT mice, PFOS induced changes that were characteristic of PPARα transactivation including regulation of genes associated with lipid metabolism, peroxisome biogenesis, proteasome activation, and inflammation. PPARα-independent changes were indicated in both WT and Null mice by altered expression of genes related to lipid metabolism, inflammation, and xenobiotic metabolism. Such results are similar to prior studies done with PFOA and are consistent with modest activation of the constitutive androstane receptor (CAR) and possibly PPARγ and/or PPARβ/δ. Unique treatment-related effects were also found in Null mice including altered expression of genes associated with ribosome biogenesis, oxidative phosphorylation and cholesterol biosynthesis. Of interest was up-regulation of Cyp7a1, a gene which is under the control of various transcription regulators. Hence, in addition to its ability to modestly activate PPARα, PFOS induces a variety of “off-target” effects as well. PPARalpha-null and wild-type male mice at 6-9 months of age were dosed by gavage for 7 consecutive days with either 0, 3, or 10 mg/kg PFOS (potassium salt) in 0.5% Tween 20. Five biological replicates consisting of individual animals were included in each dosage group. Data were compared to results previously published by our group for PFOA and Wy-14,643, a commonly used agonist of PPARalpha (Rosen et al., Toxicol Pathol. 36:592-607, 2008; GSE9796)

Dataset Information

Transcriptional profilling of liver from C57BL/6 wildtype and PPARα-knockout mice treated with PFOA and GenX after 20 weeks of high-fat diet

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure