Metabolomic and lipidomic studies on the intervention of taurochenodeoxycholic acid in mice with hyperlipidemia

Bile acids are the main component of animal bile and are directly involved in the metabolic process of lipids in vivo. Taurochenodeoxycholic acid (TCDCA) is the primary biologically active substance in bile acids and has biological functions such as antioxidant, antipyretic, anti-inflammatory, and analgesic activities and improves immunity. In the present study, we assessed the impact of TCDCA on hyperlipidemia development in mouse models. Mice were fed a high-fat diet (HFD) to induce hyperlipidemia and orally administered different doses of TCDCA orally for 30 days. Then, indicators such as triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) in mice were detected. Using HE and ORO staining techniques, the morphology of the mice's liver tissue was detected. Based on metabolomic and lipidomic analyses, we determined the mechanism of TCDCA in treating hyperlipidemia. The results showed that TCDCA had a significant ameliorating effect on dietary hyperlipidemia. In addition, it exerted therapeutic effects through glycerophospholipid metabolism.

Serum concentration of taurochenodeoxycholic acid predicts clinically significant portal hypertension

BACKGROUND & AIMS

Severity of portal hypertension is usually quantified by measuring the hepatic venous pressure gradient (HVPG). However, due to its invasiveness, alternative markers are being sought. Bile acids (BA), being synthesized, metabolized, and transported by the liver, seem to have the potential to serve as endogenous markers. The aim of the present study was to determine whether serum BA reflect the severity of portal hypertension.

METHODS

We correlated serum concentrations of individual BA with portal pressure (as HVPG) in an exploratory cohort of 21 cirrhotic patients with portal hypertension. The predictive potential of selected candidates was then confirmed in an independent validation cohort (n = 214). Additionally, nine previously published noninvasive markers were added to the stepwise logistic regression model to identify the most relevant ones, which were eventually used to create a prognostic index of portal hypertension.

RESULTS

Serum levels of taurochenodeoxycholic acid (TCDCA) significantly correlated with HVPG and showed a high potential to predict clinically significant portal hypertension (HVPG ≥ 10 mm Hg: AUROC = 0.97 ± 0.06). This was confirmed in the validation cohort (AUROC = 0.96 ± 0.01). The predictive index (constructed based on AST/ALT, spleen diameter, and TCDCA concentration) was able to distinguish clinically significant portal hypertension with 95% sensitivity and 76% specificity.

CONCLUSIONS

TCDCA seems to be a promising noninvasive marker of clinically significant portal hypertension. Its predictive potential may be further enhanced when it is combined with both the AST/ALT ratio and spleen diameter.

Taurochenodeoxycholic Acid Increases cAMP Content via Specially Interacting with Bile Acid Receptor TGR5

Taurochenodeoxycholic acid (TCDCA) is one of the main components of bile acids (BAs). TCDCA has been reported as a signaling molecule, exerting anti-inflammatory and immunomodulatory functions. However, it is not well known whether those effects are mediated by TGR5. This study aimed to elucidate the interaction between TCDCA and TGR5. To achieve this aim, first, the TGR5 eukaryotic vector was constructed. The expression level of TGR5 in 293T cells was determined by immunofluorescence, real-time quantitative PCR (RT-PCR, qPCR), and Western blot. The luciferase assay, fluorescence microscopy, and enzyme-linked immunosorbent assay (ELISA) were recruited to check the interaction of TCDCA with TGR5. TCDCA treatment in 293T cells resulted in TGR5 internalization coupled with a significant increase in cAMP luciferase expression. Our results demonstrated that TCDCA was able to bind to the TGR5 receptor and activate it. These results provide an excellent potential therapeutic target for TCDCA research. Moreover, these findings also provide theoretical evidence for further TCDCA research.

Taurochenodeoxycholic acid inhibits the proliferation and invasion of gastric cancer and induces its apoptosis

Taurochenodeoxycholic acid (TCDCA) is the principal ingredient of Compound Shougong Powder. Despite traditional Chinese medicine (TCM) research demonstrates that Compound Shougong Powder can restrict tumor growth, whether TCDCA exerts a role in suppressing cancer as the major ingredient of Compound Shougong Powder remains unknown. This study aims to clarify the regulatory mechanism of TCDCA on gastric cancer. Gastric cancer cells SGC-7901 were cultured to investigate the effects of TCDCA on proliferation and apoptosis. Furthermore, a subcutaneously implanted tumor model was established using SGC-7901 cells in BALB/C nude mice and tumor volume was measured under low and high dose treatment of TCDCA. Cell proliferation, apoptosis, and invasion were subjected to 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay, flow cytometry, and transwell assay. Differentially expressed genes were screened by transcriptome sequencing. Nude mouse tumorigenicity assay was initiated to identify the effect of TCDCA on both tumor volume and weight, and the expression of candidate genes screened by transcriptome sequencing was determined by real-time fluorescence quantification (qPCR) and Western blot. The experiments revealed that TCDCA could significantly inhibit the proliferation and invasion of gastric cancer cells and induce apoptosis of these cells. Meanwhile, test findings via in vivo indicated that TCDCA severely diminished the volume and weight of tumors. This study first demonstrated that TCDCA inhibited the proliferation and invasion of gastric cancer and induced apoptosis, which is expected to serve as an experimental basis for the application of TCM in tumor therapeutic options. PRACTICAL APPLICATIONS: Through this study, the inhibitory effect of Taurochenodeoxycholic acid on gastric cancer can be clarified, which provides a new research basis for the application of traditional Chinese medicine (TCM) and TCM monomer in cancer. In addition, this study can further promote the research and application of Chinese traditional medicine, which has important application value and economic benefits.

A combination of three plasma bile acids as a putative biomarker for schizophrenia

The aim of the present study is to determine whether plasma bile acids (BAs) could be used as an auxiliary diagnostic biomarker to distinguish patients with schizophrenia from healthy controls. Seventeen different BAs were quantitatively measured in plasma of 12 healthy participants and 12 patients with schizophrenia. Then, the data were subjected to correlation and linear discriminant analysis (LDA). The concentrations of cholic acid (CA), taurochenodeoxycholic acid (TCDCA) and taurodeoxycholic acid (TDCA) were significantly decreased in plasma of the schizophrenia patients. Correlation analysis showed the concentrations of CA, TCDCA and TDCA were negatively correlated with schizophrenia. In addition, LDA demonstrated that combination of CA, TCDCA and TDCA with a classification formula could predict correctly classified cases and the accuracy of prediction was up to 95.83%. Combination of the three BAs may be useful to diagnose schizophrenia in plasma samples.

Taurochenodeoxycholic Acid Inhibited AP-1 Activation via Stimulating Glucocorticoid Receptor

Taurochenodeoxycholic acid (TCDCA) as a primary bioactive substance of animal bile has been shown to exert good anti-inflammatory and immunomodulatory functions in adjuvant arthritis in rats. The anti-inflammatory and immunomodulatory properties of TCDCA have exhibited interesting similarities with the effects of glucocorticoids (GCs). To investigate the potential mechanisms of TCDCA in anti-inflammation and immunomodulation, we used a luciferase reporter assay to evaluate the activation of the glucocorticoid receptor (GR) stimulated by TCDCA. Our results showed that GR was activated by TCDCA in a concentration-dependent manner. Moreover, the elevated expressions of c-Fos and phosphorylated c-Jun induced by interleukin-1β (IL-1β) were reversed by TCDCA. The inhibition of TCDCA on the transactivation of activator protein-1 (AP-1) was observed as well. However, the suppression of TCDCA on the phosphorylation of c-Jun was blocked incompletely by GR inhibitor RU486. These results have indicated that the anti-inflammatory and immunomodulatory functions of TCDCA involve multiple pathways, with contributions from GR and its related AP-1 signaling pathway.

Differential activation of the human farnesoid X receptor depends on the pattern of expressed isoforms and the bile acid pool composition. Biochem Pharmacol. 2013;86:926-939. [PMID: 23928191 DOI: 10.1016/j.bcp.2013.07.022]

The farnesoid X receptor (FXR) is a key sensor in bile acid homeostasis. Although four human FXR isoforms have been identified, the physiological role of this diversity is poorly understood. Here we investigated their subcellular localization, agonist sensitivity and response of target genes. Measurement of mRNA revealed that liver predominantly expressed FXRα1(+/-), whereas FXRα2(+/-) were the most abundant isoforms in kidney and intestine. In all cases, the proportion of FXRα(1/2)(+) and FXRα(1/2)(-) isoforms, i.e., with and without a 12bp insert, respectively, was approximately 50%. When FXR was expressed in liver and intestinal cells the magnitude of the response to GW4064 and bile acids differs among FXR isoforms. In both cell types the strongest response was that of FXRα1(-). Different efficacy of bile acids species to activate FXR was found. The four FXR isoforms shared the order of sensitivity to bile acids species. When in FXR-deficient cells FXR was transfected, unconjugated, but not taurine- and glycine-amidated bile acids, were able to activate FXR. In contrast, human hepatocytes and cell lines showing an endogenous expression of FXR were sensitive to both unconjugated and conjugated bile acids. This suggests that to activate FXR conjugated, but not unconjugated, bile acids require additional component(s) of the intracellular machinery not related with uptake processes, which are missing in some tumor cells. In conclusion, cell-specific pattern of FXR isoforms determine the overall tissue sensitivity to FXR agonists and may be involved in the differential response of FXR target genes to FXR activation.

Progressive stages of mitochondrial destruction caused by cell toxic bile salts

The cell-toxic bile salt glycochenodeoxycholic acid (GCDCA) and taurochenodeoxycholic acid (TCDCA) are responsible for hepatocyte demise in cholestatic liver diseases, while tauroursodeoxycholic acid (TUDCA) is regarded hepatoprotective. We demonstrate the direct mitochondrio-toxicity of bile salts which deplete the mitochondrial membrane potential and induce the mitochondrial permeability transition (MPT). The bile salt mediated mechanistic mode of destruction significantly differs from that of calcium, the prototype MPT inducer. Cell-toxic bile salts initially bind to the mitochondrial outer membrane. Subsequently, the structure of the inner boundary membrane disintegrates. And it is only thereafter that the MPT is induced. This progressive destruction occurs in a dose- and time-dependent way. We demonstrate that GCDCA and TCDCA, but not TUDCA, preferentially permeabilize liposomes containing the mitochondrial membrane protein ANT, a process resembling the MPT induction in whole mitochondria. This suggests that ANT is one decisive target for toxic bile salts. To our knowledge this is the first report unraveling the consecutive steps leading to mitochondrial destruction by cell-toxic bile salts.