Increased bile lithogenicity by SCP2 via HMGCR and CYP7A1 regulation in human hepatocytes

Investigating the potential mechanism and therapeutic effects of SLXG for cholesterol gallstone treatment

BACKGROUND

Shugan Lidan Xiaoshi Granules (SLXG) is a traditional Chinese medicine (TCM) formulation frequently employed to prevent and treat cholesterol gallstones. SLXG is formulated based on the Chaihu Shugan Formula found in an ancient Chinese medical book, a traditional remedy in China for centuries, and has demonstrated successful treatment of numerous patients with gallbladder stones.

PURPOSE

This research sought to clarify the therapeutic impact and molecular mechanisms of SLXG and its active components in the treatment of cholesterol gallbladder stones.

METHODS

The study employed network pharmacology, UPLC-HRMS transcriptome sequencing, animal model experiments, molecular docking, and Surface Plasmon Resonance (SPR) to explore the molecular mechanisms of SLXG and its relationship with Traditional Chinese Medicines (TCMs) and potential targets. Furthermore, PPI network analysis, along with GO and KEGG enrichment analyses, were performed to explore the potential mechanisms through which SLXG and its active ingredient, naringenin, prevent and treat cholesterol gallstones. The mechanism of action was further elucidated using an animal model for gallbladder stone formation.

RESULTS

The study employed a network pharmacology and UPLC-HRMS to investigate the active compounds of SLXG for the treatment of cholesterol gallbladder stones, and subsequently constructed a network of therapeutic targets of SLXG. The results from gene enrichment analyses indicated that SLXG targets the metabolic pathway of bile secretion and the cholesterol metabolism pathway in addressing cholesterol gallbladder stones. The molecular docking results confirmed the interaction between the genes enriched in the pathways and the active ingredients in SLXG. Transcriptome sequencing results demonstrated that SLXG exerts its therapeutic effect on gallstones by regulating cholesterol and bile acid synthesis and metabolism. Furthermore, animal model experiments and SPR provided evidence that SLXG and its active ingredient, naringenin, exert therapeutic effects on cholesterol gallbladder stones by targeting the genes HMGCR, SOAT2, and UGT1A1, and influencing substances associated with cholesterol synthesis and metabolism.

CONCLUSIONS

Using systematic network pharmacology methods combined with in vivo validation experiments, we uncovered the fundamental pharmacological effects and potential mechanisms of SLXG and its active ingredient, naringenin, in the treatment of cholesterol gallstones. This research underscores the valuable role that traditional remedies can play in addressing medical challenges and suggests a promising direction for further exploration of natural treatments for the disease.

Resistance to Cholesterol Gallstone Disease: Hepatic Cholesterol Metabolism

Cholesterol gallstone disease (CGD) is one of the most common digestive diseases, and it is closely associated with hepatic cholesterol metabolism. Cholesterol gallstones may be caused by abnormal hepatic cholesterol metabolism, such as excessive cholesterol biosynthesis within the liver, interfering with the uptake or export of cholesterol in the liver, and abnormal hepatic cholesterol esterification. In this review, we begin with a brief overview of the clinical diagnosis and treatment of gallstone disease (GSD). Then, we briefly describe the major processes of hepatic cholesterol metabolism and summarize the key molecular expression changes of hepatic cholesterol metabolism in patients with gallstones. We review and analyze the recent advances in elucidating the relationships between these key molecules and CGD, and some targets significantly impacting on CGD via hepatic cholesterol metabolism are also listed. We also provide a significant discussion on the relationship between CGD and nonalcoholic fatty liver disease (NAFLD). Finally, the new discoveries of some therapeutic strategies associated with hepatic cholesterol metabolism to prevent and treat CGD are summarized.

SCP2 variant is associated with alterations in lipid metabolism, brainstem neurodegeneration, and testicular defects

BACKGROUND

The detoxification of very long-chain and branched-chain fatty acids and the metabolism of cholesterol to form bile acids occur largely through a process called peroxisomal β-oxidation. Mutations in several peroxisomal proteins involved in β-oxidation have been reported, resulting in diseases characterized by neurological defects. The final step of the peroxisomal β-oxidation pathway is catalyzed by sterol carrier protein-x (SCPx), which is encoded by the SCP2 gene. Previously, there have been two reports of SCPx deficiency, which resulted from a homozygous or compound heterozygous SCP2 mutation. We report herein the first patient with a heterozygous SCP2 mutation leading to SCPx deficiency.

RESULTS

Clinical presentations of the patient included progressive brainstem neurodegeneration, cardiac dysrhythmia, muscle wasting, and azoospermia. Plasma fatty acid analysis revealed abnormal values of medium-, long-, and very long-chain fatty acids. Protein expression of SCPx and other enzymes involved in β-oxidation were altered between patient and normal fibroblasts. RNA sequencing and lipidomic analyses identified metabolic pathways that were altered between patient and normal fibroblasts including PPAR signaling, serotonergic signaling, steroid biosynthesis, and fatty acid degradation. Treatment with fenofibrate or 4-hydroxytamoxifen increased SCPx levels, and certain fatty acid levels in patient fibroblasts.

CONCLUSIONS

These findings suggest that the patient's SCP2 mutation resulted in decreased protein levels of SCPx, which may be associated with many metabolic pathways. Increasing SCPx levels through pharmacological interventions may reverse some effects of SCPx deficiency. Collectively, this work provides insight into many of the clinical consequences of SCPx deficiency and provides evidence for potential treatment strategies.

Effects of Angelica dahurica on obesity and fatty liver in mice

Angelica dahurica (A. dahurica) is a traditional Chinese medicinal plant being used in clinical practice. The present study demonstrated that A. dahurica could reduce white-fat weight in high-fat-diet hyperlipidemic mice, decrease total cholesterol and triglyceride concentrations in the livers of both high-fat-diet and Triton WR1339 induced hyperlipidemic mice, and enhance the total hepatic lipase activities of them. These findings were further supported by the results derived from the experiments with HepG2 cells in vitro. In addition, the proteins related to lipids metabolism were investigated using LC-MS/MS, indicating that genes of lipid metabolism and lipid transport were regulated by A. dhurica. The results from LC-MS/MS were further conformed by Western blot and real time PCR assays. A. dahurica could down-regulate the expression of catalase (CAT) and sterol carrier protein2 (SCP2) and up-regulate the expression of lipid metabolism related genes-lipase member C (LIPC) and peroxisome proliferator-activated receptor gamma (PPARγ). In the Triton WR1339 mouse liver and HepG2 cells in vitro, A. dahurica was able to increase the expression of LIPC and PPARγ, confirming the results from in vivo experiments. Imperatorin showed the same activity as A. dahurica, suggesting it was one of the major active ingredients of the herb. In conclusion, our work represented a first investigation demonstrating that A. dahurica was able to regulate lipid metabolism and could be developed as a novel approach to fighting against fatty liver and obesity.