Schisandrin A in Schisandra chinensis Upregulates the LDL Receptor by Inhibiting PCSK9 Protein Stabilization in Steatotic Model.
Study Goal
The researchers aimed to determine whether Schisandra chinensis extract (SCE) and its active component schisandrin A (SA) could reduce cholesterol levels by inhibiting PCSK9 and upregulating LDLR expression.
Results Summary
SCE supplementation attenuated increases in blood LDL cholesterol and liver enzymes caused by a Western diet in mice, while SA reduced PCSK9 protein levels and increased LDLR expression in HepG2 cells. The effects were linked to PCSK9 protein degradation rather than reduced gene expression.
Population
Male mice fed a Western diet and HepG2 cells treated with delipidated serum.
Effective Dosage
1% SCE in diet for mice; non-toxic concentrations of SA for HepG2 cells (specific amounts not provided).
Duration
12 weeks for mice; cell study duration not specified.
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Schisandra chinensis extract (SCE) | decrease | hypocholesterolemia | - | - | protects against | #1 |
Western diet (WD) | increase | final body weight | Male mice | - | increased | #2 |
Western diet (WD) | increase | blood LDL cholesterol levels | Male mice | - | increased | #3 |
Western diet (WD) | increase | alanine transaminase and aspartate aminotransferase expression | Male mice | - | increased | #4 |
SCE supplementation | decrease | blood markers caused by WD | Male mice | - | significantly attenuated the increase | #5 |
SCE | decrease | WD-mediated increases in hepatic LDLR protein expression | obese mice | - | attenuated | #6 |
SCE | increase | LDLR protein expression | HepG2 cells supplemented with delipidated serum (DLPS) | - | increased | #7 |
SCE | decrease | cellular PCSK9 levels | HepG2 cells supplemented with delipidated serum (DLPS) | - | attenuated | #8 |
schisandrin A (SA) | increase | LDLR expression | DLPS-treated HepG2 cells | - | significantly increased | #9 |
schisandrin A (SA) | decrease | PCSK9 protein levels | DLPS-treated HepG2 cells | - | tended to decrease | #10 |
SA treatment | decrease | PCSK9 secretion | - | - | significantly reduced | #11 |
SA treatment | decrease | free cholesterol levels | - | - | contributing to reductions | #12 |
Schisandra chinensis extract (SCE) protects against hypocholesterolemia by inhibiting proprotein convertase subtilisin/kexin 9 (PCSK9) protein stabilization. We hypothesized that the hypocholesterolemic activity of SCE can be attributable to upregulation of the PCSK9 inhibition-associated low-density lipoprotein receptor (LDLR). Male mice were fed a low-fat diet or a Western diet (WD) containing SCE at 1% for 12 weeks. WD increased final body weight and blood LDL cholesterol levels as well as alanine transaminase and aspartate aminotransferase expression. However, SCE supplementation significantly attenuated the increase in blood markers caused by WD. SCE also attenuated WD-mediated increases in hepatic LDLR protein expression in the obese mice. In addition, SCE increased LDLR protein expression and attenuated cellular PCSK9 levels in HepG2 cells supplemented with delipidated serum (DLPS). Non-toxic concentrations of schisandrin A (SA), one of the active components of SCE, significantly increased LDLR expression and tended to decrease PCSK9 protein levels in DLPS-treated HepG2 cells. High levels of SA-mediated PCSK9 attenuation was not attributable to reduced PCSK9 gene expression, but was associated with free PCSK9 protein degradation in this cell model. Our findings show that PCSK9 secretion can be significantly reduced by SA treatment, contributing to reductions in free cholesterol levels.