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Updated: Mar 2, 2026
07:54
Cholesterol Efflux Assay
Published on: March 6, 2012
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E2F1 inhibits circulating cholesterol clearance by regulating Pcsk9 expression in the liver.
Qiuwen Lai1, Albert Giralt1,2, Cédric Le May3
1Department of Physiology.
JCI Insight
|May 19, 2017
Summary
The transcription factor E2F1 regulates liver cholesterol uptake by controlling PCSK9. Loss of E2F1 disrupts cholesterol homeostasis, leading to fatty liver and fibrosis in mice on a high-cholesterol diet.
Area of Science:
- Molecular Biology
- Hepatology
- Metabolic Diseases
Background:
- Cholesterol accumulation in the liver is an early hallmark of nonalcoholic fatty liver disease (NAFLD).
- Maintaining cellular cholesterol homeostasis is critical for liver health.
Purpose of the Study:
- To investigate the role of E2F1 in regulating cellular cholesterol homeostasis.
- To elucidate the mechanism by which E2F1 influences cholesterol uptake and NAFLD pathogenesis.
Main Methods:
- Utilized E2f1 knockout (E2f1-/-) mouse models and primary hepatocytes.
- Employed gene expression analysis, cholesterol level measurements, and low-density lipoprotein (LDL) uptake assays.
- Performed Chromatin Immunoprecipitation sequencing (ChIP-Seq) and PCSK9 promoter reporter assays.
Main Results:
- E2F1 deletion decreased proprotein convertase subtilisin/kexin 9 (PCSK9) expression and increased low-density lipoprotein receptor (LDLR) expression.
- E2f1-/- hepatocytes showed enhanced LDL uptake.
- E2F1 was confirmed to bind and transactivate the PCSK9 promoter.
- E2f1-/- mice on a high-cholesterol diet developed fatty liver and fibrosis, which was ameliorated by PCSK9 reexpression.
Conclusions:
- E2F1 plays a critical role in regulating hepatic cholesterol uptake by modulating PCSK9 expression.
- Loss of E2F1 function leads to abnormal cholesterol accumulation and promotes liver fibrosis in response to a high-cholesterol diet.
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