Interactions Between Signaling Pathways
MAPK Signaling Cascades
The JAK-STAT Signaling Pathway
NF-κB-dependent Signaling Pathway
Regulation of Nuclear Protein Sorting
Amplifying Signals via Enzymatic Cascade
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Updated: Jul 12, 2026

LDL Cholesterol Uptake Assay Using Live Cell Imaging Analysis with Cell Health Monitoring
Published on: November 17, 2018
Seahyoung Lee1, Hyun-Joung Lim, Jin-Hee Park
1Yonsei Cardiovascular Genome Center, College of Medicine, Yonsei University, Seoul, Republic of Korea.
This study explored whether berberine, a natural compound, increases LDL receptor (LDLR) expression through the JNK signaling pathway. Previous work showed that berberine lowers lipids by stabilizing LDLR mRNA via the ERK pathway. The researchers tested if JNK was also involved. Using RT-PCR, they found that the JNK inhibitor SP600125 reduced berberine's effect on LDLR mRNA. Luciferase assays showed increased LDLR promoter activity after berberine treatment. EMSA confirmed that berberine induces c-jun binding to the LDLR promoter, and this was reduced by SP600125. The results suggest that berberine increases LDLR transcription via the JNK pathway. This expands the known mechanisms of berberine's lipid-lowering effects.
Area of Science:
Background:
Prior research has shown that berberine lowers lipids by stabilizing hepatic LDLR mRNA in an ERK-dependent way. However, biological systems often involve multiple interacting pathways. No prior work had resolved whether other pathways also contribute to LDLR up-regulation by berberine. This gap motivated further investigation into alternative signaling mechanisms. The JNK pathway is known to regulate transcription in various contexts. Yet, its role in berberine-induced LDLR regulation remained unclear. This uncertainty drove the current study's focus on JNK involvement. The study aimed to determine if JNK signaling contributes to berberine's effects on LDLR. Understanding this could refine therapeutic applications of berberine.
Purpose Of The Study:
The aim of this study was to investigate if the JNK pathway contributes to berberine-induced LDLR up-regulation. The researchers proposed that other pathways beyond ERK might be involved in this process. They sought to test whether JNK inhibition would affect berberine's impact on LDLR. The study also aimed to identify if c-jun binding to the LDLR promoter is involved. The motivation was to expand the understanding of berberine's mechanisms. This could help clarify how berberine modulates LDLR transcriptionally. The work was driven by the need to explore alternative signaling routes. The findings could inform future studies on berberine's therapeutic use.
Main Methods:
The researchers used RT-PCR to assess LDLR mRNA levels after berberine treatment. They pretreated cells with the JNK inhibitor SP600125 to test pathway involvement. Luciferase assays were employed to evaluate LDLR promoter activity. A putative c-jun binding site in the LDLR promoter was examined. Electrophoretic mobility shift assays (EMSA) were used to detect c-jun binding. The study tested whether berberine induces c-jun binding to LDLR DNA. SP600125 pretreatment was used to confirm JNK pathway involvement. The methods combined molecular biology techniques to probe transcriptional mechanisms.
Main Results:
Berberine-induced LDLR mRNA expression was reduced by SP600125 pretreatment. Luciferase assays showed increased LDLR promoter activity after berberine treatment. The putative c-jun binding site was found to be important for this effect. EMSA confirmed berberine-induced c-jun binding to the LDLR promoter. SP600125 pretreatment decreased this binding. These findings suggest JNK pathway involvement in LDLR up-regulation. The results indicate that berberine activates the LDLR promoter transcriptionally. The study provides evidence that JNK signaling contributes to this process.
Conclusions:
The study demonstrates that berberine increases LDLR promoter activity. The JNK pathway is involved in this transcriptional up-regulation. SP600125 pretreatment reduced berberine's effect on LDLR mRNA. The c-jun binding site in the LDLR promoter is important for this process. EMSA results confirm berberine-induced c-jun binding to LDLR DNA. These findings suggest JNK signaling contributes to LDLR regulation. The authors propose that JNK pathway activation is part of berberine's mechanism. The study supports the idea that multiple pathways may be involved in berberine's effects.
The authors propose that berberine increases LDLR transcription through the JNK pathway. This was demonstrated using SP600125 pretreatment and EMSA.
Electrophoretic mobility shift assays (EMSA) confirmed that berberine induces c-jun binding to the LDLR promoter.
SP600125 is a JNK inhibitor used to test whether the JNK pathway contributes to berberine-induced LDLR up-regulation.
The putative c-jun binding site in the LDLR promoter is important for berberine-induced transcriptional activity.
SP600125 pretreatment reduced berberine-induced LDLR mRNA expression and c-jun binding.
The study suggests that berberine increases LDLR promoter activity through JNK pathway activation.