The lack of PPARα exacerbated the progression of non-alcoholic steatohepatitis in mice with spleen deficiency syndrome by triggering an inflammatory response

Front Immunol. 2024 Apr 3:15:1381340. doi: 10.3389/fimmu.2024.1381340. eCollection 2024.

Abstract

Background: In addition to abnormal liver inflammation, the main symptoms of non-alcoholic steatohepatitis (NASH) are often accompanied by gastrointestinal digestive dysfunction, consistent with the concept of spleen deficiency (SD) in traditional Chinese medicine. As an important metabolic sensor, whether peroxisome proliferator-activated receptor alpha (PPARα) participates in regulating the occurrence and development of NASH with SD (NASH-SD) remains to be explored.

Methods: Clinical liver samples were collected for RNA-seq analysis. C57BL/6J mice induced by folium sennae (SE) were used as an SD model. qPCR analysis was conducted to evaluate the inflammation and metabolic levels of mice. PPARα knockout mice (PPARαko) were subjected to SE and methionine-choline-deficient (MCD) diet to establish the NASH-SD model. The phenotype of NASH and the inflammatory indicators were measured using histopathologic analysis and qPCR as well.

Results: The abnormal expression of PPARα signaling, coupled with metabolism and inflammation, was found in the results of RNA-seq analysis from clinical samples. SD mice showed a more severe inflammatory response in the liver evidenced by the increases in macrophage biomarkers, inflammatory factors, and fibrotic indicators in the liver. qPCR results also showed differences in PPARα between SD mice and control mice. In PPARαko mice, further evidence was found that the lack of PPARα exacerbated the inflammatory response phenotype as well as the lipid metabolism disorder in NASH-SD mice.

Conclusion: The abnormal NR signaling accelerated the vicious cycle between lipotoxicity and inflammatory response in NAFLD with SD. Our results provide new evidence for nuclear receptors as potential therapeutic targets for NAFLD with spleen deficiency.

Keywords: PPARα; inflammatory response; lipid metabolism; non-alcoholic steatohepatitis; nuclear receptor.

MeSH terms

  • Animals
  • Inflammation
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Non-alcoholic Fatty Liver Disease* / genetics
  • Non-alcoholic Fatty Liver Disease* / metabolism
  • PPAR alpha* / metabolism
  • Spleen / metabolism
  • Spleen / pathology

Substances

  • PPAR alpha

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was financially supported by the National Natural Science Foundation of China (82160891, 82304826), Key Projects of Guangdong Provincial Department of Education (2021ZDZX2010), Basic and Applied Basic Research Project of Guangzhou (202201011501, 2022010101340, 202201011240), Guangdong Basic and Applied Basic Research Foundation (2020A1515110732), and Science and Technology Planning Project of Guangzhou (202201020349).