Genistein upregulates LDLR levels via JNK-mediated activation of SREBP-2

Medicia Kartawijaya, Hye Won Han, Yunhye Kim, Seung-Min Lee

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Background: Genistein has been proved in vitro and in vivo to lower LDLR level. It is also widely consumed and implicated for its anti-atherogenic effects. However, the molecular mechanism by which genistein lowers the LDL level is still unknown. Objective: To understand the anti-atherogenic molecular mechanism of action, genistein was investigated for its impact on the expression of LDLR, the receptor for LDL cholesterol, and related signaling pathways in a human hepatoma cell line. Design: HepG2 cell was used for the experiments. Genistein with different concentrations was diluted in media and was incubated for 24 h or more as indicated. Protein levels were measured by western blotting, and mRNA expression was detected by RT-qPCR. Chromatin immunoprecipitation assay (CHIP) assay was used to determine protein binding levels, and luciferase assay was used to measure promoter activity. Result: Genistein increased the mRNA and protein levels of LDLR in a time-dependent manner. Genistein increased the transcriptional activity of the LDLR promoter containing the reporter gene (pLDLR-luc, 805 to 50). But the sterol regulatory element deletion mutant construct failed to be activated by genistein. Genistein increased the nuclear fraction of SREBP-2 and the DNA-binding activity of SREBP-2 to LDLR promoter, as assessed by CHIP. The genistein-phosphorylated JNK inhibitor (SP600126) abolished the genistein-stimulated levels of LDLR and the nuclear SREBP-2. The addition of cholesterol up to 5 mg/mL for 24 h did not affect the effect of genistein on LDLR protein expression. Even the addition of 40 mM genistein increased the cholesterol uptake by more than 10% in the human hepatoma cell line. Conclusion: Our data support the idea that genistein may have anti-atherogenic effects by activating JNK signals and SREBP-2 processing, which is followed by the upregulation of LDLR.

Original languageEnglish
Article number31120
JournalFood and Nutrition Research
Volume60
DOIs
Publication statusPublished - 2016 May 20

Fingerprint

Genistein
genistein
Up-Regulation
Chromatin Immunoprecipitation
promoter regions
assays
hepatoma
chromatin
Hepatocellular Carcinoma
Cholesterol
cell lines
cholesterol
Cell Line
Messenger RNA
Proteins
protein binding
Hep G2 Cells
Sterols
luciferase
Luciferases

All Science Journal Classification (ASJC) codes

  • Food Science
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health

Cite this

@article{c2af35dee6ba4e29995a8008bff2a73f,
title = "Genistein upregulates LDLR levels via JNK-mediated activation of SREBP-2",
abstract = "Background: Genistein has been proved in vitro and in vivo to lower LDLR level. It is also widely consumed and implicated for its anti-atherogenic effects. However, the molecular mechanism by which genistein lowers the LDL level is still unknown. Objective: To understand the anti-atherogenic molecular mechanism of action, genistein was investigated for its impact on the expression of LDLR, the receptor for LDL cholesterol, and related signaling pathways in a human hepatoma cell line. Design: HepG2 cell was used for the experiments. Genistein with different concentrations was diluted in media and was incubated for 24 h or more as indicated. Protein levels were measured by western blotting, and mRNA expression was detected by RT-qPCR. Chromatin immunoprecipitation assay (CHIP) assay was used to determine protein binding levels, and luciferase assay was used to measure promoter activity. Result: Genistein increased the mRNA and protein levels of LDLR in a time-dependent manner. Genistein increased the transcriptional activity of the LDLR promoter containing the reporter gene (pLDLR-luc, 805 to 50). But the sterol regulatory element deletion mutant construct failed to be activated by genistein. Genistein increased the nuclear fraction of SREBP-2 and the DNA-binding activity of SREBP-2 to LDLR promoter, as assessed by CHIP. The genistein-phosphorylated JNK inhibitor (SP600126) abolished the genistein-stimulated levels of LDLR and the nuclear SREBP-2. The addition of cholesterol up to 5 mg/mL for 24 h did not affect the effect of genistein on LDLR protein expression. Even the addition of 40 mM genistein increased the cholesterol uptake by more than 10{\%} in the human hepatoma cell line. Conclusion: Our data support the idea that genistein may have anti-atherogenic effects by activating JNK signals and SREBP-2 processing, which is followed by the upregulation of LDLR.",
author = "Medicia Kartawijaya and Han, {Hye Won} and Yunhye Kim and Seung-Min Lee",
year = "2016",
month = "5",
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doi = "10.3402/fnr.v60.31120",
language = "English",
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journal = "Food and Nutrition Research",
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Genistein upregulates LDLR levels via JNK-mediated activation of SREBP-2. / Kartawijaya, Medicia; Han, Hye Won; Kim, Yunhye; Lee, Seung-Min.

In: Food and Nutrition Research, Vol. 60, 31120, 20.05.2016.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Genistein upregulates LDLR levels via JNK-mediated activation of SREBP-2

AU - Kartawijaya, Medicia

AU - Han, Hye Won

AU - Kim, Yunhye

AU - Lee, Seung-Min

PY - 2016/5/20

Y1 - 2016/5/20

N2 - Background: Genistein has been proved in vitro and in vivo to lower LDLR level. It is also widely consumed and implicated for its anti-atherogenic effects. However, the molecular mechanism by which genistein lowers the LDL level is still unknown. Objective: To understand the anti-atherogenic molecular mechanism of action, genistein was investigated for its impact on the expression of LDLR, the receptor for LDL cholesterol, and related signaling pathways in a human hepatoma cell line. Design: HepG2 cell was used for the experiments. Genistein with different concentrations was diluted in media and was incubated for 24 h or more as indicated. Protein levels were measured by western blotting, and mRNA expression was detected by RT-qPCR. Chromatin immunoprecipitation assay (CHIP) assay was used to determine protein binding levels, and luciferase assay was used to measure promoter activity. Result: Genistein increased the mRNA and protein levels of LDLR in a time-dependent manner. Genistein increased the transcriptional activity of the LDLR promoter containing the reporter gene (pLDLR-luc, 805 to 50). But the sterol regulatory element deletion mutant construct failed to be activated by genistein. Genistein increased the nuclear fraction of SREBP-2 and the DNA-binding activity of SREBP-2 to LDLR promoter, as assessed by CHIP. The genistein-phosphorylated JNK inhibitor (SP600126) abolished the genistein-stimulated levels of LDLR and the nuclear SREBP-2. The addition of cholesterol up to 5 mg/mL for 24 h did not affect the effect of genistein on LDLR protein expression. Even the addition of 40 mM genistein increased the cholesterol uptake by more than 10% in the human hepatoma cell line. Conclusion: Our data support the idea that genistein may have anti-atherogenic effects by activating JNK signals and SREBP-2 processing, which is followed by the upregulation of LDLR.

AB - Background: Genistein has been proved in vitro and in vivo to lower LDLR level. It is also widely consumed and implicated for its anti-atherogenic effects. However, the molecular mechanism by which genistein lowers the LDL level is still unknown. Objective: To understand the anti-atherogenic molecular mechanism of action, genistein was investigated for its impact on the expression of LDLR, the receptor for LDL cholesterol, and related signaling pathways in a human hepatoma cell line. Design: HepG2 cell was used for the experiments. Genistein with different concentrations was diluted in media and was incubated for 24 h or more as indicated. Protein levels were measured by western blotting, and mRNA expression was detected by RT-qPCR. Chromatin immunoprecipitation assay (CHIP) assay was used to determine protein binding levels, and luciferase assay was used to measure promoter activity. Result: Genistein increased the mRNA and protein levels of LDLR in a time-dependent manner. Genistein increased the transcriptional activity of the LDLR promoter containing the reporter gene (pLDLR-luc, 805 to 50). But the sterol regulatory element deletion mutant construct failed to be activated by genistein. Genistein increased the nuclear fraction of SREBP-2 and the DNA-binding activity of SREBP-2 to LDLR promoter, as assessed by CHIP. The genistein-phosphorylated JNK inhibitor (SP600126) abolished the genistein-stimulated levels of LDLR and the nuclear SREBP-2. The addition of cholesterol up to 5 mg/mL for 24 h did not affect the effect of genistein on LDLR protein expression. Even the addition of 40 mM genistein increased the cholesterol uptake by more than 10% in the human hepatoma cell line. Conclusion: Our data support the idea that genistein may have anti-atherogenic effects by activating JNK signals and SREBP-2 processing, which is followed by the upregulation of LDLR.

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