Effects of perfluorooctanoic acid (PFOA) on gene expression profiles via nuclear receptors in HepaRG cells: Comparative study with in vitro transactivation assays.
Toxicology 2023:153577. [PMID:
37302725 DOI:
10.1016/j.tox.2023.153577]
[Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 05/31/2023] [Accepted: 06/08/2023] [Indexed: 06/13/2023]
Abstract
Perfluorooctanoic acid (PFOA), a synthetic perfluorinated eight-carbon organic chemical, has been reported to induce hepatotoxicity, including increased liver weight, hepatocellular hypertrophy, necrosis, and increased peroxisome proliferation in rodents. Epidemiological studies have demonstrated associations between serum PFOA levels and various adverse effects. In this study, we investigated the gene expression profiles of human HepaRG cells exposed to 10 and 100 μM PFOA for 24h. Treatment with 10 and 100 μM PFOA significantly modulated the expression of 190 genes and 996 genes, respectively. In particular, genes upregulated or downregulated by 100µM PFOA included peroxisome proliferator-activated receptor (PPAR) signaling genes related to lipid metabolism, adipocyte differentiation, and gluconeogenesis. In addition, we identified the "Nuclear receptors-meta pathways" following the activation of other nuclear receptors: constitutive androstane receptor (CAR), pregnane X receptor (PXR) and farnesoid X receptor (FXR), and the transcription factor, nuclear factor E2-related factor 2 (Nrf2). The expression levels of some target genes (CYP4A11, CYP2B6, CYP3A4, CYP7A1, and GPX2) of these nuclear receptors and Nrf2 were confirmed using quantitative reverse transcription polymerase chain reaction. Next, we performed transactivation assays using COS-7 or HEK293 cells to investigate whether these signaling-pathways were activated by the direct effects of PFOA on human PPARα, CAR, PXR, FXR and Nrf2. PFOA activated PPARα in a concentration-dependent manner, but did not activate CAR, PXR, FXR, or Nrf2. Taken together, these results suggest that PFOA affects the hepatic transcriptomic responses of HepaRG cells through direct activation of PPARα and indirect activation of CAR, PXR FXR and Nrf2. Our finding indicates that PPARα activation found in the "Nuclear receptors-meta pathways" functions as a molecular initiating event for PFOA, and indirect activation of alternative nuclear receptors and Nrf2 also provide important molecular mechanisms in PFOA-induced human hepatotoxicity.
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