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Updated: Sep 21, 2025
Inducing and Characterizing Vesicular Steatosis in Differentiated HepaRG Cells
Published on: July 18, 2019
Comparative Transcriptome Analysis Reveals That Exendin-4 Improves Steatosis in HepG2 Cells by Modulating Signaling
Khaoula Errafii1,2,3, Olfa Khalifa2, Neyla S Al-Akl2
1College of Health and Life Sciences, Hamad Bin Khalifa University, Qatar Foundation, Doha P.O. Box 34110, Qatar.
Abstract:
No therapy exists for non-alcoholic fatty liver disease (NAFLD). However, glucagon-like peptide receptor agonists (GLP-1RAs) showed a beneficial effect on NAFLD, although the underpinning mechanisms remain unclear due to their pleiotropic effects. We examined the implicated signaling pathways using comparative transcriptomics in a cell model of steatosis to overcome pleiotropy. We treated steatotic HepG2 cells with the GLP-1RA Exendin-4 (Ex-4). We compared the transcriptome profiles of untreated steatotic, and Ex-4-treated steatotic cells, and used Ingenuity Pathway Analysis (IPA) to identify the signaling pathways and associated genes involved in the protective effect of Ex-4. Ex-4 treatment significantly reduces steatosis. RNA-seq analysis revealed 209 differentially expressed genes (DEGs) between steatotic and untreated cells, with farnesoid X receptor/retinoid X receptor (FXR/RXR) (p = 8.9 × 10-7) activation being the top regulated canonical pathway identified by IPA. Furthermore, 1644 DEGs were identified between steatotic cells and Ex-4-treated cells, with liver X receptor/retinoid X receptor (LXR/RXR) (p = 2.02 × 10-7) and FXR/RXR (p = 3.28 × 10-7) activation being the two top canonical pathways. The top molecular and cellular functions between untreated and steatotic cells were lipid metabolism, molecular transport, and small molecular biochemistry, while organismal injury and abnormalities, endocrine system disorders, and gastrointestinal disease were the top three molecular and cellular functions between Ex-4-treated and steatotic cells. Genes overlapping steatotic cells and Ex-4-treated cells were associated with several lipid metabolism processes. Unique transcriptomic differences exist between steatotic cells and Ex-4-treated steatotic cells, providing an important resource for understanding the mechanisms that underpin the protective effect of GLP-1RAs on NAFLD and for the identification of novel therapeutic targets for NAFLD.
Insights
Glucagon-like peptide receptor agonists (GLP-1RAs) reduce liver fat in non-alcoholic fatty liver disease (NAFLD) models. Transcriptomics revealed that GLP-1RAs activate key pathways like LXR/RXR and FXR/RXR, offering new therapeutic targets.
Area of Science:
- Molecular biology
- Hepatology
- Pharmacology
Background:
- Non-alcoholic fatty liver disease (NAFLD) currently lacks specific therapies.
- Glucagon-like peptide receptor agonists (GLP-1RAs) show promise for NAFLD treatment, but their mechanisms are not fully understood due to complex effects.
- Investigating signaling pathways is crucial for elucidating GLP-1RA efficacy in NAFLD.
Purpose of the Study:
- To identify the molecular mechanisms underlying the protective effects of GLP-1 receptor agonists (GLP-1RAs) on non-alcoholic fatty liver disease (NAFLD).
- To utilize comparative transcriptomics in a cell model to overcome the pleiotropic effects of GLP-1RAs.
- To pinpoint key signaling pathways and genes involved in GLP-1RA-mediated steatosis reduction.
Main Methods:
- Steatotic HepG2 cells were treated with Exendin-4 (Ex-4), a GLP-1RA.
- Comparative transcriptomic analysis (RNA-seq) was performed on untreated steatotic cells versus Ex-4-treated steatotic cells.
- Ingenuity Pathway Analysis (IPA) was employed to identify regulated canonical pathways and associated genes.
Main Results:
- Ex-4 treatment significantly reduced steatosis in the cell model.
- RNA-seq identified 1644 differentially expressed genes between steatotic and Ex-4-treated cells.
- Top canonical pathways activated by Ex-4 were Liver X receptor/Retinoid X receptor (LXR/RXR) and Farnesoid X receptor/Retinoid X receptor (FXR/RXR) signaling.
- Genes affected by Ex-4 were predominantly involved in lipid metabolism, molecular transport, and small molecule biochemistry.
Conclusions:
- GLP-1RA treatment, exemplified by Ex-4, effectively mitigates steatosis in a cellular model of NAFLD.
- The protective effects are associated with the activation of LXR/RXR and FXR/RXR signaling pathways.
- These findings provide a valuable transcriptomic resource for understanding GLP-1RA mechanisms in NAFLD and identifying novel therapeutic targets.
