ORIGINAL RESEARCH article

Front. Pharmacol.

Sec. Experimental Pharmacology and Drug Discovery

Volume 16 - 2025 | doi: 10.3389/fphar.2025.1595566

Molecular Mechanisms of Dose-Dependent Regulation of Hepatic Lipid Metabolism by BaP through Modulation of AhR Binding to XRE1 or XRE3

Provisionally accepted
Mengdi  ZhangMengdi Zhang1,2Xiaoli  LvXiaoli Lv1,2Chaojie  WangChaojie Wang1,2Lei  WangLei Wang1,2Han  WangHan Wang1,2Xue  WangXue Wang1,2Yulu  DuYulu Du1,2Jun  LiJun Li1,2Xiuli  HanXiuli Han1,2,3Lei  FanLei Fan1,2Yuxia  HuYuxia Hu1,2,3*Tuya  BaiTuya Bai1,2*Weizhong  HuangfuWeizhong Huangfu4*Fuhou  ChangFuhou Chang1,2*
  • 1College of Pharmacy, Inner Mongolia Medical University, Hohhot, Inner Mongolia Autonomous Region, China
  • 2Inner Mongolia Autonomous Region Engineering Research Center of New Pharmaceutical Screening, Inner Mongolia Medical University, Hohhot, China
  • 3Center for New Drug Safety Evaluation and Research, Inner Mongolia Medical University, Hohhot, China
  • 4Affiliated hospital of Inner Mongolia Medical University, Hohhot, China

The final, formatted version of the article will be published soon.

Benzo[a]pyrene (BaP), a polycyclic aromatic hydrocarbon and a potent environmental pollutant, has been implicated in the dysregulation of lipid metabolism and metabolic diseases, warranting investigation into its effects on liver functions, particularly regarding fibroblast growth factor 21 (FGF21) mediated pathways. This study aimed to elucidate the effects of BaP on liver lipid metabolism and FGF21 expression via the aryl hydrocarbon receptor (AhR), with a focus on the regulatory interactions between BaP and xenobiotic response elements (XRE) within the promoter region of FGF21. Utilizing HepG2 cells, lipid accumulation was assessed through Oil Red O and Nile Red staining, while the expression of FGF21 protein was quantified by Western blotting and immunofluorescence techniques. Additionally, various truncated plasmids of the FGF21 promoter were synthesized for a dual-luciferase reporter assay to determine the relative luciferase activity and the modulation of FGF21 expression by BaP. The results revealed dose-dependent effects of BaP on lipid metabolism; specifically, low concentrations of BaP upregulated FGF21 expression by enhancing promoter activity in regions containing the XRE1 sequence, whereas higher BaP concentrations downregulated FGF21 expression via inhibition of promoter activity in regions with the XRE3 sequence. In conclusion, low doses of BaP facilitate AhR binding to XRE1, promoting FGF21 expression, while high doses disrupt this interaction through XRE3, culminating in decreased expression levels. These findings suggest a nuanced role of BaP in lipid metabolism regulation, with potential implications for understanding metabolic disorders associated with environmental pollutants. The study elucidates the relationship between AhR and FGF-21, providing an experimental basis for the search of new targets for the prevention and treatment of nonalcoholic fatty liver disease (NAFLD).

Keywords: Benzo[a]pyren, fibroblast growth factor 21, Aryl hydrocarbon receptor, xenobiotic response element 1, xenobiotic response element 3, Hepatic lipid metabolism

Received: 18 Mar 2025; Accepted: 20 Jun 2025.

Copyright: © 2025 Zhang, Lv, Wang, Wang, Wang, Wang, Du, Li, Han, Fan, Hu, Bai, Huangfu and Chang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Yuxia Hu, College of Pharmacy, Inner Mongolia Medical University, Hohhot, Inner Mongolia Autonomous Region, China
Tuya Bai, College of Pharmacy, Inner Mongolia Medical University, Hohhot, Inner Mongolia Autonomous Region, China
Weizhong Huangfu, Affiliated hospital of Inner Mongolia Medical University, Hohhot, China
Fuhou Chang, College of Pharmacy, Inner Mongolia Medical University, Hohhot, Inner Mongolia Autonomous Region, China

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.