Related Experiment Video
Updated: Oct 31, 2025
Optimized Analysis of In Vivo and In Vitro Hepatic Steatosis
Published on: March 11, 2017
Silybin Restored CYP3A Expression through the Sirtuin 2/Nuclear Factor κ-B Pathway in Mouse Nonalcoholic Fatty Liver
Ran Zhang1, Dan Xu1, Yirui Zhang1
1Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China (R.Z., Y.Z., R.W., Y.L., H.Z., J.A., G.W., Y.X.); Research and Development Center, Nanjing Chia Tai Tianqing Pharmaceutical co., Ltd., Nanjing, China (D.X.); and Department of Pharmacy, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing, China (N.Y.).
Abstract:
Silybin is widely used as a hepatoprotective agent in various liver disease therapies and has been previously identified as a CYP3A inhibitor. However, little is known about the effect of silybin on CYP3A and the regulatory mechanism during high-fat-diet (HFD)-induced liver inflammation. In our study, we found that silybin restored CYP3A expression and activity that were decreased by HFD and conditioned medium (CM) from palmitate-treated Kupffer cells. Moreover, silybin suppressed liver inflammation in HFD-fed mice and inhibited nuclear factor κ-B translocation into the nucleus through elevation of SIRT2 expression and promotion of p65 deacetylation. This effect was confirmed by overexpression of SIRT2, which suppressed p65 nuclear translocation and restored CYP3A transcription affected by CM. The hepatic NAD+ concentration markedly decreased in HFD-fed mice and CM-treated hepatocytes/HepG2 cells but increased after silybin treatment. Supplementing nicotinamide mononucleotide as an NAD+ donor inhibited p65 acetylation, decreased p65 nuclear translocation, and restored cyp3a transcription in both HepG2 cells and mouse hepatocytes. These results suggest that silybin regulates metabolic enzymes during liver inflammation by a mechanism related to the increase in NAD+ and SIRT2 levels. In addition, silybin enhanced the intracellular NAD+ concentration by decreasing poly-ADP ribosyl polymerase-1 expression. In summary, silybin increased NAD+ concentration, promoted SIRT2 expression, and lowered p65 acetylation both in vivo and in vitro, which supported the recovery of CYP3A expression. These findings indicate that the NAD+/SIRT2 pathway plays an important role in CYP3A regulation during nonalcoholic fatty liver disease. SIGNIFICANCE STATEMENT: This research revealed the differential regulation of CYP3A by silybin under physiological and fatty liver pathological conditions. In the treatment of nonalcoholic fatty liver disease, silybin restored, not inhibited, CYP3A expression and activity through the NAD+/ sirtuin 2 pathway in accordance with its anti-inflammatory effect.
Insights
Silybin treatment restores liver CYP3A expression and activity in fatty liver disease by increasing NAD+ and SIRT2 levels, reducing inflammation and improving metabolic enzyme function.
Area of Science:
- Biochemistry
- Hepatology
- Pharmacology
Background:
- Silybin is a known hepatoprotective agent and CYP3A inhibitor.
- The effect of silybin on CYP3A regulation during high-fat-diet (HFD)-induced liver inflammation is not well understood.
Purpose of the Study:
- To investigate the mechanism by which silybin affects CYP3A expression and activity in the context of HFD-induced liver inflammation.
- To elucidate the role of the NAD+/SIRT2 pathway in silybin's regulatory effects.
Main Methods:
- Utilized HFD-fed mice, palmitate-treated Kupffer cells, and HepG2 cells.
- Assessed CYP3A expression and activity, nuclear factor kappa-B (NF-κB) translocation, SIRT2 expression, and NAD+ levels.
- Investigated the effects of silybin, SIRT2 overexpression, and nicotinamide mononucleotide (NAD+ donor).
Main Results:
- Silybin restored decreased CYP3A expression and activity in HFD-induced liver inflammation.
- Silybin suppressed liver inflammation by inhibiting NF-κB translocation via SIRT2 elevation and p65 deacetylation.
- Silybin increased hepatic NAD+ concentration, which was linked to restored CYP3A transcription.
Conclusions:
- Silybin regulates metabolic enzymes during liver inflammation through the NAD+/SIRT2 pathway.
- The NAD+/SIRT2 pathway is crucial for CYP3A regulation in nonalcoholic fatty liver disease.
- Silybin's anti-inflammatory effects are associated with the restoration of CYP3A expression and activity.
