Microbial-derived metabolites are important mediators of host-microbial interactions. In recent years, the role of intestinal microbial metabolites in colorectal cancer has attracted considerable attention. These metabolites, which can be derived from bacterial metabolism of dietary substrates, modification of host molecules such as bile acids, or directly from bacteria, strongly influence the progression of colitis-associated cancer (CAC) by regulating inflammation and immune response. Here, we review how microbiome metabolites short-chain fatty acids (SCFAs), secondary bile acids, polyamines, microbial tryptophan metabolites, and polyphenols are involved in the tumorigenesis and development of CAC through inflammation and immunity. Given the heated debate on the metabolites of microbiota in maintaining gut homeostasis, serving as tumor molecular markers, and affecting the efficacy of immune checkpoint inhibitors in recent years, strategies for the prevention and treatment of CAC by targeting intestinal microbial metabolites are also discussed in this review.
Humans ; Gastrointestinal Microbiome/physiology* ; Animals ; Carcinogenesis/metabolism* ; Colitis-Associated Neoplasms/microbiology* ; Fatty Acids, Volatile/metabolism* ; Bile Acids and Salts/metabolism* ; Colitis/microbiology*

BACKGROUND: Bile acids (BAs) facilitate the progression of gastric intestinal metaplasia (GIM). Long non-coding RNAs (lncRNAs) dysregulation was observed along with the initiation of gastric cancer. However, how lncRNAs function in GIM remains unclear. This study aimed to explore the role and mechanism of lncRNA PVT1 in GIM, and provide a potential therapeutic target for GIM treatment. METHODS: We employed RNA sequencing (RNA-seq) to screen dysregulated lncRNAs in gastric epithelial cells after BA treatment. Bioinformatics analysis was conducted to reveal the regulatory mechanism. PVT1 expression was detected in 21 paired biopsies obtained under endoscopy. Overexpressed and knockdown cell models were established to explore gene functions in GIM. Molecular interactions were validated by dual-luciferase reporter assay, RNA immunoprecipitation (RIP), and chromatin immunoprecipitation (Ch-IP). The levels of relative molecular expression were detected in GIM tissues. RESULTS: We confirmed that lncRNA PVT1 was upregulated in BA-induced GIM model. PVT1 promoted the expression of intestinal markers such as CDX2 , KLF4 , and HNF4α . Bioinformatics analysis revealed that miR-34b-5p was a putative target of PVT1 . miR-34b-5p mimics increased CDX2 , KLF4 , and HNF4α levels. Restoration of miR-34b-5p decreased the pro-metaplastic effect of PVT1 . The interactions between PVT1 , miR-34b-5p, and the downstream target HNF4α were validated. Moreover, HNF4α could transcriptionally activated PVT1 , sustaining the GIM phenotype. Finally, the activation of the PVT1 /miR-34b-5p/ HNF4α loop was detected in GIM tissues. CONCLUSIONS BAs facilitate GIM partially via a PVT1/miR-34b-5p/HNF4α positive feedback loop. PVT1 may become a novel target for blocking the continuous development of GIM and preventing the initiation of gastric cancer in patients with bile reflux.
Humans ; RNA, Long Noncoding/metabolism* ; MicroRNAs/metabolism* ; Hepatocyte Nuclear Factor 4/genetics* ; Bile Acids and Salts ; Kruppel-Like Factor 4 ; Metaplasia/metabolism*

This study aims to investigate the potential effect of the water extract of fresh Rehmanniae Radix on hypercholesterolemia in mice that was induced by a high-fat and high-cholesterol diet and explore its possible mechanism from bile acid reabsorption. Male C57BL/6 mice were randomly assigned into the following groups: control, model, low-and high-dose(4 and 8 g·kg~(-1), respectively) fresh Rehmanniae Radix, and positive drug(simvastatin, 0.05 g·kg~(-1)). Other groups except the control group were fed with a high-fat and high-cholesterol diet for 6 consecutive weeks to induce hypercholesterolemia. From the 6th week, mice were administrated with corresponding drugs daily via gavage for additional 6 weeks, while continuing to be fed with a high-fat and high-cholesterol diet. Serum levels of total cholesterol(TC), triglycerides(TG), low density lipoprotein-cholesterol(LDL-c), high density lipoprotein-cholesterol(HDL-c), and total bile acid(TBA), as well as liver TC and TG levels and fecal TBA level, were determined by commercial assay kits. Hematoxylin-eosin(HE) staining, oil red O staining, and transmission electron microscopy were performed to observe the pathological changes in the liver. Three livers samples were randomly selected from each of the control, model, and high-dose fresh Rehmanniae Radix groups for high-throughput transcriptome sequencing. Differentially expressed genes were mined and KEGG pathway enrichment analysis was performed to predict the key pathways and target genes of the water extract of fresh Rehmanniae Radix in the treatment of hypercholesterolemia. RT-qPCR was employed to measure the mRNA levels of cholesterol 7α-hydroxylase(CYP7A1) and cholesterol 27α-hydroxylase(CYP27A1) in the liver. Western blot was employed to determine the protein levels of CYP7A1 and CYP27A1 in the liver as well as farnesoid X receptor(FXR), apical sodium-dependent bile acid transporter(ASBT), and ileum bile acid-binding protein(I-BABP) in the ileum. The results showed that the water extract of fresh Rehmanniae Radix significantly lowered the levels of TC and TG in the serum and liver, as well as the level of LDL-c in the serum. Conversely, it elevated the level of HDL-c in the serum and TBA in feces. No significant difference was observed in the level of TBA in the serum among groups. HE staining, oil red O staining, and transmission electron microscopy showed that the water extract reduced the accumulation of lipid droplets in the liver. Further mechanism studies revealed that the water extract of fresh Rehmanniae Radix significantly down-regulated the protein levels of FXR and bile acid reabsorption-related proteins ASBT and I-BABP. Additionally, it enhanced CYP7A1 and CYP27A1, the key enzymes involved in bile acid synthesis. Therefore, it is hypothesized that the water extract of fresh Rehmanniae Radix may exert an anti-hypercholesterolemic effect by regulating FXR/ASBT/I-BABP signaling, inhibiting bile acid reabsorption, and increasing bile acid excretion, thus facilitating the conversion of cholesterol to bile acids.
Animals ; Male ; Bile Acids and Salts/metabolism* ; Mice, Inbred C57BL ; Mice ; Diet, High-Fat/adverse effects* ; Cholesterol/metabolism* ; Drugs, Chinese Herbal/administration & dosage* ; Hypercholesterolemia/genetics* ; Receptors, Cytoplasmic and Nuclear/genetics* ; Rehmannia/chemistry* ; Liver/drug effects* ; Humans ; Cholesterol 7-alpha-Hydroxylase/genetics* ; Plant Extracts

Gegen Qinlian Decoction(GQD) is a classic prescription for the clinical treatment of ulcerative colitis(UC). This study, based on the differences in efficacy observed in UC mice under different level of bile acids treated with GQD, aims to clarify the impact of bile acids on UC and its therapeutic effects. It further investigates the expression of bile acid receptors in the liver of UC mice, and preliminarily reveals the mechanism through which GQD affects bile acid synthesis in the treatment of UC. A UC mouse model was established using dextran sulfate sodium(DSS) induction. The efficacy of GQD was evaluated by assessing the general condition, disease activity index(DAI) score, colon length, and histopathological changes in colon tissue via hematoxylin and eosin(HE) staining. ELISA and Western blot were used to evaluate the inflammatory response in colon tissue. The total bile acid(TBA) level and liver damage were quantified using an automatic biochemistry analyzer. The expression levels of bile acid receptors and bile acid synthetases in liver tissue were detected by Western blot and RT-qPCR. The results showed that compared with the model group, GQD treatment significantly improved the DAI score, colon shortening, and histopathological damage in UC mice. The levels of pro-inflammatory factors TNF-α and IL-6 in the colon were significantly reduced. Serum TBA levels were significantly decreased, while alkaline phosphatase(ALP) levels significantly increased. After administration of cholic acid(CA), UC symptoms in the CA + GQD group were significantly aggravated compared with the GQD group. The DAI score, degree of weight loss, colon injury, serum TBA, and liver injury markers all increased significantly. However, compared with the CA group, the CA + GQD group showed a marked reduction in TBA levels and a significant improvement in UC-related symptoms, indicating that GQD can alleviate UC damage exacerbated by CA. Further investigation into the expression of bile acid receptors and synthetases in the liver showed that under GQD treatment, the expression of farnesoid X receptor(FXR) and small heterodimer partner(SHP) significantly increased, while the expression of G protein-coupled receptor 5(TGR5) and cholesterol 7α-hydroxylase(Cyp7A1) significantly decreased. These findings suggest that GQD may affect bile acid receptors and synthetases, inhibiting bile acid synthesis through the FXR/SHP pathway to treat UC.
Animals ; Colitis, Ulcerative/genetics* ; Bile Acids and Salts/biosynthesis* ; Drugs, Chinese Herbal/administration & dosage* ; Mice ; Male ; Humans ; Receptors, Cytoplasmic and Nuclear/metabolism* ; Colon/metabolism* ; Disease Models, Animal ; Liver/metabolism* ; Mice, Inbred C57BL

Emodin is a hydroxyanthraquinone compound that is widely distributed and has multiple pharmacological activities, including anti-diarrheal, anti-inflammatory, and liver-protective effects. Research indicates that emodin may be one of the main components responsible for inducing hepatotoxicity. However, studies on the mechanisms of liver injury are relatively limited, particularly those related to bile acids(BAs) metabolism. This study aims to systematically investigate the effects of different dosages of emodin on BAs metabolism, providing a basis for the safe clinical use of traditional Chinese medicine(TCM)containing emodin. First, this study evaluated the safety of repeated administration of different dosages of emodin over a 5-week period, with a particular focus on its impact on the liver. Next, the composition and content of BAs in serum and liver were analyzed. Subsequently, qRT-PCR was used to detect the mRNA expression of nuclear receptors and transporters related to BAs metabolism. The results showed that 1 g·kg~(-1) emodin induced hepatic damage, with bile duct hyperplasia as the primary pathological manifestation. It significantly increased the levels of various BAs in the serum and primary BAs(including taurine-conjugated and free BAs) in the liver. Additionally, it downregulated the mRNA expression of farnesoid X receptor(FXR), retinoid X receptor(RXR), and sodium taurocholate cotransporting polypeptide(NTCP), and upregulated the mRNA expression of cholesterol 7α-hydroxylase(CYP7A1) in the liver. Although 0.01 g·kg~(-1) and 0.03 g·kg~(-1) emodin did not induce obvious liver injury, they significantly increased the level of taurine-conjugated BAs in the liver, suggesting a potential interference with BAs homeostasis. In conclusion, 1 g·kg~(-1) emodin may promote the production of primary BAs in the liver by affecting the FXR-RXR-CYP7A1 pathway, inhibit NTCP expression, and reduce BA reabsorption in the liver, resulting in BA accumulation in the peripheral blood. This disruption of BA homeostasis leads to liver injury. Even doses of emodin close to the clinical dose can also have a certain effect on the homeostasis of BAs. Therefore, when using traditional Chinese medicine or formulas containing emodin in clinical practice, it is necessary to regularly monitor liver function indicators and closely monitor the risk of drug-induced liver injury.
Emodin/administration & dosage* ; Bile Acids and Salts/metabolism* ; Animals ; Male ; Liver/injuries* ; Chemical and Drug Induced Liver Injury/genetics* ; Drugs, Chinese Herbal/adverse effects* ; Humans ; Rats, Sprague-Dawley ; Mice ; Rats

A targeted metabolomics study was conducted on the bile acid profiles in the liver and feces of rats induced by a high-fat diet and intervened by ginsenoside Rb_1, along with the detection of FXR pathway gene expression in the liver, to explore and clarify its mechanism of action. The content of biochemical indicators in the serum were detected using an automatic biochemical analyzer. Hematoxylin and eosin(HE) staining and oil red O staining were used to detect pathological changes and lipid deposition in the liver. RT-PCR was used to detect the mRNA expression of FXR, small heterodimer partner(SHP), cholesterol 7 alpha-hydroxylase(CYP7A1), and sterol regulatory element-binding protein-1c(SREBP-1c) in the liver. Targeted bile acid metabolomics technology was employed to analyze changes in bile acid profiles in liver tissue and feces, and a correlation analysis was performed between key genes such as FXR, SHP, CYP7A1, SREBP-1c and differential bile acid metabolites. The results showed that ginsenoside Rb_1 significantly reduced the levels of total cholesterol(TC), triglycerides(TG), low-density lipoprotein cholesterol(LDL-C), and high-density lipoprotein cholesterol(HDL-C) in the serum, alleviated the large fat vacuoles and lipid deposition in the liver, increased the expression of FXR mRNA in the liver, and decreased the expression of SREBP-1c mRNA. The expression of CYP7A1 and SHP mRNA was increased, but the differences were not statistically significant. Targeted bile acid metabolomics showed that ginsenoside Rb_1 could restore the levels of 9 bile acids in the liver and 8 bile acids in the feces. Ginsenoside Rb_1 also increased the percentage of taurocholic acid(TCA) in the liver(56.78%) and the percentage of 12-ketolithocholic acid(12-KLCA) in the feces(26.10%). Pathway enrichment analysis revealed two pathways involved in bile acid metabolism: primary bile acid biosynthesis and taurine and hypotaurine metabolism. Correlation analysis showed that FXR, SHP, CYP7A1, and SREBP-1c were positively correlated with multiple differential bile acids. These results suggest that ginsenoside Rb_1 may intervene in lipid metabolism disorders induced by a high-fat diet by regulating the FXR pathway and modulating bile acid profiles in the liver and feces.
Animals ; Bile Acids and Salts/metabolism* ; Rats ; Ginsenosides/pharmacology* ; Male ; Receptors, Cytoplasmic and Nuclear/genetics* ; Liver/drug effects* ; Diet, High-Fat/adverse effects* ; Metabolomics ; Rats, Sprague-Dawley ; Feces/chemistry* ; Cholesterol 7-alpha-Hydroxylase/metabolism* ; Sterol Regulatory Element Binding Protein 1/genetics* ; Humans

Objective To investigate the causal relationship between serum total bile acid (TBA) levels and gastric cancer (GC) using regression discontinuity design (RDD). Methods A total of 1244 GC patients and 1333 healthy controls were included in the study. Demographic characteristics, gallbladder disease history, tumor markers, and serum TBA levels were collected from both groups. Logistic regression was used to construct a risk prediction model to estimate the risk of GC. RDD was employed with serum TBA as the grouping variable and the individual risk of developing GC as the outcome variable. Results The predictive factors in the GC risk prediction model included age, sex, body mass index(BMI), serum TBA, carcinoembryoniv antigen(CEA), alpha fetoprotein(AFP), carbohydrate antigen 199(CA199), and CA125. Serum TBA was identified as an independent risk factor for GC (OR=1.054, 95% CI: 1.030 to 1.079). RDD analysis indicated that when serum TBA levels reached 8 μmol/L, the probability of developing GC increased sharply by 23.7%. The breakpoint remained statistically significant following validity and robustness assessments. Conclusion The study demonstrates a positive causal relationship between serum TBA levels and GC, when the serum TBA level reaches 8 μmol/L, the risk of an individual developing GC increases sharply.
Humans ; Stomach Neoplasms/etiology* ; Male ; Female ; Middle Aged ; Bile Acids and Salts/blood* ; Aged ; Adult ; Risk Factors ; Case-Control Studies ; Biomarkers, Tumor/blood* ; Logistic Models

OBJECTIVES: To investigate the therapeutic mechanism of Wendan Decoction for phlegm syndrome in rats with metabolic syndrome (MS). METHODS: Forty Wistar rats were randomly divided into normal control group (n=8) and 3 phlegm syndrome model groups (induced by high-fat, high-sugar, and high-salt feeding and a single-dose intraperitoneal STZ injection; n=24) treated with daily gavage of saline, Wendan Decoction (3.6 g/kg), or metformin (0.1 g/kg) for 4 weeks. General conditions and glucose and lipid metabolism parameters of the rats were monitored, and serum LPS, liver histopathology, hepatic expressions of FXR, CYP7A1 and FGFR4 and ileal expressions of FXR and FGF15 were examined. Gut microbiota structure was analyzed using 16S rDNA sequencing, and serum bile acids were quantified with UHPLC-MS/MS. RESULTS: The rat models of phlegm syndrome exhibited severe hepatic steatosis and necrosis, increased body weight, abdominal circumference, Lee's index, FBG, FINS, HOMA-IR, TG, TC, LDL and LPS, and decreased HDL level. The abundance of Bacteroidetes, Megamonas, and Bacteroides in gut microbiota increased while Firmicutes, Lachnospiraceae_NK4A136_group, isohyodeoxycholic acid, and glycohyodeoxycholic acid decreased significantly; hepatic FXR and FGFR4 expressions and ileal FXR and FGF15 expressions decreased while hepatic CYP7A1 expression increased significantly in the rat models. Treatment with Wendan Decoction effectively alleviated hepatic pathology, reduced body weight and abdominal circumference, improved glucose and lipid metabolic profiles and gut microbiota structure, and reversed the changes in hepatic and ileal protein expressions. Correlation analysis revealed that Firmicutes and Lachnospiraceae_NK4A136_group were positively correlated while Bacteroidetes, Megamonas and Bacteroides were negative correlated with the levels of isohyodeoxycholic acid and hyodeoxycholic acid. CONCLUSIONS Wendan Decoction can significantly improve metabolic profiles in rats with phlegm syndrome of MS possibly by regulating the intestinal flora-bile acid axis to modulate the intestinal flora structure and maintain bile acid homeostasis via the FXR signaling pathway.
Animals ; Gastrointestinal Microbiome/drug effects* ; Metabolic Syndrome/microbiology* ; Bile Acids and Salts/metabolism* ; Rats, Wistar ; Drugs, Chinese Herbal/therapeutic use* ; Rats ; Male ; Fibroblast Growth Factors/metabolism* ; Liver/metabolism* ; Cholesterol 7-alpha-Hydroxylase/metabolism* ; Receptors, Cytoplasmic and Nuclear/metabolism*

OBJECTIVES: To investigate the therapeutic efficacy and mechanism of pentosan polysulfate (PPS) for cyclophosphamide (CYP)-induced interstitial cystitis/bladder pain syndrome (IC/BPS) in mice. METHODS: Female C57BL/6 mice (6-8 weeks old) were randomized into control group, PPS treatment (25 mg/kg via gavage for 3 weeks) group, CYP treatment (3 separate intraperitoneal injections at 50 mg/kg in week 4), and CYP+PPS treatment group. Gut microbiota alterations of the mice were analyzed using 16S rDNA sequencing and non-targeted metabolomics. Fecal microbiota transplantation (FMT) was performed in CYP-treated recipient mice and those treated with both CYP and PPS. In the in vitro experiment, LPS-stimulated human bladder epithelial cells (SV-HUC-1) were used to assess the effects of deoxycholic acid (DCA) and TGR5 signaling inhibitor SBI-115 on barrier functions of bladder epithelial cells. RESULTS: PPS treatment significantly improved the mechanical pain thresholds, restored the urodynamic parameters, and attenuated bladder inflammation and barrier dysfunction in CYP-treated mice. Mechanistically, PPS enriched the abundance of Eubacterium xylanophilum and increased DCA levels in the intestines of CYP-treated mice. FMT experiments confirmed microbiota-dependent therapeutic effects of PPS, shown by reduced bladder pathology in the recipient mice treated with both CYP and PPS. In SV-HUC-1 cells, DCA obviously alleviated LPS-induced inflammation and barrier disruption, and treatment with SBI-115 abolished these protective effects of DCA. CONCLUSIONS PPS ameliorates IC/BPS in mice by remodeling gut microbiota to enhance DCA production and activate TGR5 signaling, suggesting a novel microbiota-bile acid-TGR5 axis that mediates the therapeutic effect of PPS and a therapeutic strategy for IC/BPS by targeting gut-bladder crosstalk.
Animals ; Cystitis, Interstitial/drug therapy* ; Gastrointestinal Microbiome/drug effects* ; Pentosan Sulfuric Polyester/therapeutic use* ; Cyclophosphamide/adverse effects* ; Mice, Inbred C57BL ; Female ; Mice ; Bile Acids and Salts/metabolism* ; Urinary Bladder ; Fecal Microbiota Transplantation ; Humans

OBJECTIVE: To Investigate the effects of lithocholic acid (LCA) on the balance between osteogenic and adipogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). METHODS: Twelve 10-week-old SPF C57BL/6J female mice were randomly divided into an experimental group (undergoing bilateral ovariectomy) and a control group (only removing the same volume of adipose tissue around the ovaries), with 6 mice in each group. The body mass was measured every week after operation. After 4 weeks post-surgery, the weight of mouse uterus was measured, femur specimens of the mice were taken for micro-CT scanning and three-dimensional reconstruction to analyze changes in bone mass. Tibia specimens were taken for HE staining to calculate the number and area of bone marrow adipocytes in the marrow cavity area. ELISA was used to detect the expression of bone turnover markers in the serum. Liver samples were subjected to real-time fluorescence quantitative PCR (RT-qPCR) to detect the expression of key genes related to bile acid metabolism, including cyp7a1, cyp7b1, cyp8b1, and cyp27a1. BMSCs were isolated by centrifugation from 2 C57BL/6J female mice (10-week-old). The third-generation cells were exposed to 0, 1, 10, and 100 μmol/L LCA, following which cell viability was evaluated using the cell counting kit 8 assay. Subsequently, alkaline phosphatase (ALP) staining and oil red O staining were conducted after 7 days of osteogenic and adipogenic induction. RT-qPCR was employed to analyze the expressions of osteogenic-related genes, namely ALP, Runt-related transcription factor 2 (Runx2), and osteocalcin (OCN), as well as adipogenic-related genes including Adiponectin (Adipoq), fatty acid binding protein 4 (FABP4), and peroxisome proliferator-activated receptor γ (PPARγ). RESULTS: Compared with the control group, the body mass of the mice in the experimental group increased, the uterus atrophied, the bone mass decreased, the bone marrow fat expanded, and the bone metabolism showed a high bone turnover state. RT-qPCR showed that the expressions of cyp7a1, cyp8b1, and cyp27a1, which were related to the key enzymes of bile acid metabolism in the liver, decreased significantly ( P<0.05), while the expression of cyp7b1 had no significant difference ( P>0.05). Intervention with LCA at concentrations of 1, 10, and 100 μmol/L did not demonstrate any apparent toxic effects on BMSCs. Furthermore, LCA inhibited the expressions of osteogenic-related genes (ALP, Runx2, and OCN) in a dose-dependent manner, resulting in a reduction in ALP staining positive area. Concurrently, LCA promoted the expressions of adipogenic-related genes (Adipoq, FABP4, and PPARγ), and an increase in oil red O staining positive area. CONCLUSION After menopause, the metabolism of bile acids is altered, and secondary bile acid LCA interferes with the balance of osteogenic and adipogenic differentiation of BMSCs, thereby affecting bone remodelling.
Female ; Mice ; Animals ; Core Binding Factor Alpha 1 Subunit/pharmacology* ; PPAR gamma/metabolism* ; Steroid 12-alpha-Hydroxylase/metabolism* ; Mice, Inbred C57BL ; Cell Differentiation ; Osteogenesis ; Mesenchymal Stem Cells ; Bile Acids and Salts/pharmacology* ; Bone Marrow Cells ; Cells, Cultured ; Azo Compounds