Chenodeoxycholic Acid Research Articles

Suppression of the gut microbiota-bile acid-FGF19 axis in patients with atrial fibrillation.

This study aimed to investigate the role of the gut microbiota (GM)-bile acid (BA)-fibroblast growth factor (FGF) 19 axis in patients with atrial fibrillation (AF). Gut bacterial metabolisms of BAs were determined in an AF metagenomic dataset. The composition of faecal BAs pools was characterized by targeted metabolomics in an independent AF cross-sectional cohort. Circulating levels of FGF19 were measured by ELISA. In vitro cell experiments were conducted to validate the regulatory role of FGF19 in atrial cardiomyocytes stimulated with palmitic acid. First, metagenomic profiling revealed that gut microbial biotransformation from primary to secondary BAs was dysregulated in AF patients. Second, the proportion of secondary BAs decreased in the faeces of patients with AF. Also, eight BAs were identified as AF-associated BAs, including seven AF-enriched BAs (ursodeoxycholic acid, chenodeoxycholic acid, etc.), and AF-decreased dehydrolithocholic acid. Third, reduced levels of circulating FGF19 were observed in patients with AF. Subsequently, FGF19 was found to protect against palmitic acid-induced lipid accumulation and dysregulated signalling in atrial cardiomyocytes, including attenuated phosphorylation of YAP and Ca2+ /calmodulin-dependent protein kinases II and secretion of interleukin-1β, mediated via peroxisome proliferator-activated receptor α. Our data found decreased levels of secondary BAs and circulating FGF19, resulting in the impaired protective function of FGF19 against lipid accumulation in atrial cardiomyocytes.

Prevention of High-Fat-Diet-Induced Dyslipidemia byLactobacillus plantarumLP104 through Mediating Bile Acid Enterohepatic Axis Circulation and Intestinal Flora

This work aimed to investigate the alleviative mechanism of Lactobacillus plantarum LP104 (LP104) isolated from kimchi on high-fat-diet-induced dyslipidemia by targeting the intestinal flora and bile acid (BA) metabolism. Oral administration of LP104 over 8 weeks reduced body weight gain and body fat, as well as ameliorating serum and hepatic dyslipidemia in HFD-fed C57BL/6N mice significantly. LP104 intervention also increased the ileal tauro-α/β-muricholic acid sodium salt (T-α-MCA or T-β-MCA) and tauroursodeoxycholic acid (TUDCA) concentrations to suppress the enterohepatic farnesoid X receptor/fibroblast growth factor 15-fibroblast growth factor receptor 4 (FXR/FGF15-FGFR4) signaling pathway, which stimulated the hepatic cholic acid (CA) and chenodeoxycholic acid (CDCA) de novo synthesis through using cholesterol. Then, LP104 treatment accelerated BA excretion with the feces and cholesterol efflux to improve HFD-caused hyperlipidemia effectively. The 16S rRNA gene high-throughput sequencing revealed that LP104 promoted intestinal flora rebalance by increasing the abundances of Bacteroides, Akkermansia, Lactobacillus, and Clostridium and decreasing the abundance of Oscillospira and Coprococcus. Meanwhile, Spearman correlation analysis demonstrated that the differential flora were closely related to BA signaling molecules including CA, CDCA, T-α-MCA, T-β-MCA, and TUDCA after LP104 intervention. These findings provided new evidence that LP104 had the potential to be used as a naturally functional food for the prevention of dyslipidemia.

Predicting cholangiocarcinoma in primary sclerosing cholangitis: using artificial intelligence, clinical and laboratory data

BackgroundPrimary sclerosing cholangitis (PSC) patients have a risk of developing cholangiocarcinoma (CCA). Establishing predictive models for CCA in PSC is important.MethodsIn a large cohort of 1,459 PSC patients seen at Mayo Clinic (1993–2020), we quantified the impact of clinical/laboratory variables on CCA development using univariate and multivariate Cox models and predicted CCA using statistical and artificial intelligence (AI) approaches. We explored plasma bile acid (BA) levels’ predictive power of CCA (subset of 300 patients, BA cohort).ResultsEight significant risk factors (false discovery rate: 20%) were identified with univariate analysis; prolonged inflammatory bowel disease (IBD) was the most important one. IBD duration, PSC duration, and total bilirubin remained significant (p < 0.05) with multivariate analysis. Clinical/laboratory variables predicted CCA with cross-validated C-indexes of 0.68–0.71 at different time points of disease, significantly better compared to commonly used PSC risk scores. Lower chenodeoxycholic acid, higher conjugated fraction of lithocholic acid and hyodeoxycholic acid, and higher ratio of cholic acid to chenodeoxycholic acid were predictive of CCA. BAs predicted CCA with a cross-validated C-index of 0.66 (std: 0.11, BA cohort), similar to clinical/laboratory variables (C-index = 0.64, std: 0.11, BA cohort). Combining BAs with clinical/laboratory variables leads to the best average C-index of 0.67 (std: 0.13, BA cohort).ConclusionsIn a large PSC cohort, we identified clinical and laboratory risk factors for CCA development and demonstrated the first AI based predictive models that performed significantly better than commonly used PSC risk scores. More predictive data modalities are needed for clinical adoption of these models.

Teaching NeuroImages: Spinal xanthomatosis

A 57-year-old woman presented with a 20-year history of progressive lower extremity weakness, spasticity, and proprioception deficits. She was given a diagnosis of primary progressive multiple sclerosis at age 38. Her Achilles tendons were enlarged (figure 1). Brain MRI was normal. Spine MRI demonstrated T2-hyperintense signal involving the posterior and lateral columns (figure 2). Serum cholestanol level was elevated. CYP27A1 gene sequencing revealed 2 pathogenic variants, c.1183C>T(p.Arg395Cys) and c.410G>A(p.Arg137Gln), confirming the diagnosis of cerebrotendinous xanthomatosis (CTX). Spinal xanthomatosis is a rare variant of CTX presenting with progressive corticospinal and posterior column signs.1 Early treatment with chenodeoxycholic acid may improve outcomes.2

Multimodal plasma metabolomics and lipidomics in elucidating metabolic perturbations in tuberculosis patients with concurrent type 2 diabetes

Type 2 diabetes mellitus (DM) poses a major burden for the treatment and control of tuberculosis (TB). Characterization of the underlying metabolic perturbations in DM patients with TB infection would yield insights into the pathophysiology of TB-DM, thus potentially leading to improvements in TB treatment. In this study, a multimodal metabolomics and lipidomics workflow was applied to investigate plasma metabolic profiles of patients with TB and TB-DM. Significantly different biological processes and biomarkers in TB-DM vs. TB were identified using a data-driven, knowledge-based framework. Changes in metabolic and signaling pathways related to carbohydrate and amino acid metabolism were mainly captured by amide HILIC column metabolomics analysis, while perturbations in lipid metabolism were identified by the C18 metabolomics and lipidomics analysis. Compared to TB, TB-DM exhibited elevated levels of bile acids and molecules related to carbohydrate metabolism, as well as the depletion of glutamine, retinol, lysophosphatidylcholine, and phosphatidylcholine. Moreover, arachidonic acid metabolism was determined as a potentially important factor in the interaction between TB and DM pathophysiology. In a correlation network of the significantly altered molecules, among the central nodes, chenodeoxycholic acid was robustly associated with TB and DM. Fatty acid (22:4) was a component of all significant modules. In conclusion, the integration of multimodal metabolomics and lipidomics provides a thorough picture of the metabolic changes associated with TB-DM. The results obtained from this comprehensive profiling of TB patients with DM advance the current understanding of DM comorbidity in TB infection and contribute to the development of more effective treatment.

Fabrication of Molecular Blocks with High Responsiveness to the Cancer Microenvironment by Ursodeoxycholic Acid.

In cancer therapy, a drug delivery system (DDS) has been widely studied to achieve selective drug accumulation at the tumor site. However, DDS still has a major drawback in that it requires multistep processes for intracellular delivery, resulting in low efficiency of drug delivery. To overcome this problem, we recently reported a molecular block (MB) that disrupts cancer cell membranes in the cancer microenvironment using deoxycholic acid (DCA). However, the MB showed considerable cytotoxicity even at neutral pH, possibly due to the structural hydrophobic property of DCA. Herein, we focused on selecting the most suitable bile acid for an MB that possessed high responsiveness to the cancer microenvironment without cytotoxicity at neutral pH. Cell viabilities of the free bile acids such as DCA, chenodeoxycholic acid (CDCA), cholic acid (CA), and ursodeoxycholic acid (UDCA) were evaluated at neutral pH (pH = 7.4) and a cancer acidic environment (pH = 6.3-6.5). The half-maximal inhibition concentration (IC50) value of UDCA at pH = 7.4 showed an approximately 7.5-fold higher IC50 value than that at pH = 6.3, whereas the other bile acids yielded less than a 4-fold IC50 value difference between the same pHs. Biocompatible poly(vinyl alcohol) (PVA) was functionalized with UDCA (PVA-UDCA) for the synthesis of higher responsiveness to the cancer microenvironment without cytotoxicity at neutral pH. Importantly, 56% pancreatic cancer cell death was observed at pH = 6.5, whereas only 10% was detected at neutral pH by the PVA-UDCA treatment. However, PVA-DCA indicated almost the same cancer cell death property, independent of pH conditions. These results suggest PVA-UDCA shows great potential for a new class of MB.

Dietary cholesterol drives the development of nonalcoholic steatohepatitis by altering gut microbiota mediated bile acid metabolism in high-fat diet fed mice

Nonalcoholic fatty liver disease (NAFLD) is the most widespread chronic liver disorder globally. Unraveling the pathogenesis of simple fatty liver to nonalcoholic steatohepatitis (NASH) has important clinical significance for improving the prognosis of NAFLD. Here, we explored the role of a high-fat diet alone or combined with high cholesterol in causing NASH progression. Our results demonstrated that high dietary cholesterol intakes accelerate the progression of spontaneous NAFLD and induces liver inflammation in mice. An elevation of hydrophobic unconjugated bile acids cholic acid (CA), deoxycholic acid (DCA), muricholic acid and chenodeoxycholic acid, was observed in high-fat and high-cholesterol diet fed mice. Full-length sequencing of the 16S rDNA gene of gut microbiota revealed a significant increase in the abundance of Bacteroides, Clostridium, and Lactobacillus that possess bile salt hydrolase activity. Furthermore, the relative abundance of these bacterial species was positively correlated with content of unconjugated bile acids in liver. Moreover, the expression of genes related to bile acid reabsorption (organic anion-transporting polypeptides, Na+-taurocholic acid cotransporting polypeptide, apical sodium dependent bile acid transporter and organic solute transporter β) was found to be increased in mice with a high-cholesterol diet. Lastly, we observed that hydrophobic bile acids CA and DCA induce an inflammatory response in free fatty acids-induced steatotic HepG2 cells. In conclusion, high dietary cholesterol promotes the development of NASH by altering gut microbiota composition and abundance and thereby influencing with bile acid metabolism.

Chenodeoxycholic acid rescues axonal degeneration in induced pluripotent stem cell-derived neurons from spastic paraplegia type 5 and cerebrotendinous xanthomatosis patients

BackgroundBiallelic mutations in CYP27A1 and CYP7B1, two critical genes regulating cholesterol and bile acid metabolism, cause cerebrotendinous xanthomatosis (CTX) and hereditary spastic paraplegia type 5 (SPG5), respectively. These rare diseases are characterized by progressive degeneration of corticospinal motor neuron axons, yet the underlying pathogenic mechanisms and strategies to mitigate axonal degeneration remain elusive.MethodsTo generate induced pluripotent stem cell (iPSC)-based models for CTX and SPG5, we reprogrammed patient skin fibroblasts into iPSCs by transducing fibroblast cells with episomal vectors containing pluripotency factors. These patient-specific iPSCs, as well as control iPSCs, were differentiated into cortical projection neurons (PNs) and examined for biochemical alterations and disease-related phenotypes.ResultsCTX and SPG5 patient iPSC-derived cortical PNs recapitulated several disease-specific biochemical changes and axonal defects of both diseases. Notably, the bile acid chenodeoxycholic acid (CDCA) effectively mitigated the biochemical alterations and rescued axonal degeneration in patient iPSC-derived neurons. To further examine underlying disease mechanisms, we developed CYP7B1 knockout human embryonic stem cell (hESC) lines using CRISPR-cas9-mediated gene editing and, following differentiation, examined hESC-derived cortical PNs. Knockout of CYP7B1 resulted in similar axonal vesiculation and degeneration in human cortical PN axons, confirming a cause-effect relationship between gene deficiency and axonal degeneration. Interestingly, CYP7B1 deficiency led to impaired neurofilament expression and organization as well as axonal degeneration, which could be rescued with CDCA, establishing a new disease mechanism and therapeutic target to mitigate axonal degeneration.ConclusionsOur data demonstrate disease-specific lipid disturbances and axonopathy mechanisms in human pluripotent stem cell-based neuronal models of CTX and SPG5 and identify CDCA, an established treatment of CTX, as a potential pharmacotherapy for SPG5. We propose this novel treatment strategy to rescue axonal degeneration in SPG5, a currently incurable condition.

Improving the Performance and High‐Field Stability of FAPbBr3 Single Crystals in X‐Ray Detection with Chenodeoxycholic Acid Additive (Small Methods 4/2023)

Inside Front Cover In article number 2201636, Yiying Zhao and co-workers demonstrate that chenodeoxycholic acid as additive can ionize the hydrogen ions and thus the decomposition of FA ions is suppressed in precursors, leading to better stoichiometry of FAPbBr3 single crystals. Meanwhile, the chenodeoxycholic acid can coordinate with Pb atoms and assist FAPbBr3 single crystal growth, resulting in a better crystal orientation.

Klebsiella quasipneumoniae in intestine damages bile acid metabolism in hematopoietic stem cell transplantation patients with bloodstream infection

BackgroundBloodstream infection (BSI) is a serious hematopoietic stem cell transplantation (HSCT) complication. The intestinal microbiome regulates host metabolism and maintains intestinal homeostasis. Thus, the impact of microbiome on HSCT patients with BSI is essential.MethodsStool and serum specimens of HSCT patients were prospectively collected from the pretransplant conditioning period till 4 months after transplantation. Specimens of 16 patients without BSI and 21 patients before BSI onset were screened for omics study using 16S rRNA gene sequencing and untargeted metabolomics. The predictive infection model was constructed using LASSO and the logistic regression algorithm. The correlation and influence of microbiome and metabolism were examined in mouse and Caco-2 cell monolayer models.ResultsThe microbial diversity and abundance of Lactobacillaceae were remarkably reduced, but the abundance of Enterobacteriaceae (especially Klebsiella quasipneumoniae) was significantly increased in the BSI group before onset, compared with the non-BSI group. The family score of microbiome features (Enterobacteriaceae and Butyricicoccaceae) could highly predict BSI (AUC = 0.879). The serum metabolomic analysis showed that 16 differential metabolites were mainly enriched in the primary bile acid biosynthesis pathway, and the level of chenodeoxycholic acid (CDCA) was positively correlated with the abundance of K. quasipneumoniae (R = 0.406, P = 0.006). The results of mouse experiments confirmed that three serum primary bile acids levels (cholic acid, isoCDCA and ursocholic acid), the mRNA expression levels of bile acid farnesol X receptor gene and apical sodium-dependent bile acid transporter gene in K. quasipneumoniae colonized mice were significantly higher than those in non-colonized mice. The intestinal villus height, crypt depth, and the mRNA expression level of tight junction protein claudin-1 gene in K. quasipneumoniae intestinal colonized mice were significantly lower than those in non-colonized mice. In vitro, K. quasipneumoniae increased the clearance of FITC-dextran by Caco-2 cell monolayer.ConclusionsThis study demonstrated that the intestinal opportunistic pathogen, K. quasipneumoniae, was increased in HSCT patients before BSI onset, causing increased serum primary bile acids. The colonization of K. quasipneumoniae in mice intestines could lead to mucosal integrity damage. The intestinal microbiome features of HSCT patients were highly predictive of BSI and could be further used as potential biomarkers.

Anti-inflammatory potential of selective small compounds by targeting TNF-α & NF-kB signaling: a comprehensive molecular docking and simulation study

Tumor necrosis factor alpha (TNF-α) is the major cause of inflammation in autoimmune diseases like rheumatoid arthritis (RA). It’s mechanisms of signal transduction through nuclear factor kappa B (NF-kB) pathway via small molecules such as metabolite crosstalk are still elusive. In this study, we have targeted TNF-α and NF-kB through metabolites of RA, to inhibit TNF-α activity and deter NF-kB signaling pathways, thereby mitigating the disease severity of RA. TNF-α and NF-kB structure was obtained from PDB database and metabolites of RA were selected from literature survey. In-silico studies were carried out by molecular docking using AutoDock Vina software and further, known TNF-α and NF-kB inhibitors were compared and revealed metabolite’s capacity to targets the respective proteins. Most suitable metabolite was then validated by MD simulation to verify its efficiency against TNF-α. Total 56 known differential metabolites of RA were docked with TNF-α and NF-kB compared to their corresponding inhibitor compounds. Four metabolites such as Chenodeoxycholic acid, 2-Hydroxyestrone, 2-Hydroxyestradiol (2-OHE2), and 16-Hydroxyestradiol were identified as a common TNF-α inhibitor’s having binding energies ranging from −8.3 to −8.6 kcal/mol, followed by docking with NF-kB. Further, 2-OHE2 was selected because of having binding energy −8.5 kcal/mol, found to inhibit inflammation and the effectiveness was validated by root mean square fluctuation, radius of gyration and molecular mechanics with generalized born and surface area solvation against TNF-α. Thus 2-OHE2, an estrogen metabolite was identified as the potential inhibitor, attenuated inflammatory activation and can be utilized as a therapeutic target to disseminate severity of RA.

Metagenomic and targeted metabolomic analyses reveal distinct phenotypes of the gut microbiota in patients with colorectal cancer and type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) is an independent risk factor for colorectal cancer (CRC), and the patients with CRC and T2DM have worse survival. The human gut microbiota (GM) is linked to the development of CRC and T2DM, respectively. However, the GM characteristics in patients with CRC and T2DM remain unclear. We performed fecal metagenomic and targeted metabolomics studies on 36 samples from CRC patients with T2DM (DCRC group, n = 12), CRC patients without diabetes (CRC group, n = 12), and healthy controls (Health group, n = 12). We analyzed the fecal microbiomes, characterized the composition and function based on the metagenomics of DCRC patients, and detected the short-chain fatty acids (SCFAs) and bile acids (BAs) levels in all fecal samples. Finally, we performed a correlation analysis of the differential bacteria and metabolites between different groups. Compared with the CRC group, LefSe analysis showed that there is a specific GM community in DCRC group, including an increased abundance of Eggerthella , Hungatella , Peptostreptococcus , and Parvimonas , and decreased Butyricicoccus , Lactobacillus , and Paraprevotella . The metabolomics analysis results revealed that the butyric acid level was lower but the deoxycholic acid and 12-keto-lithocholic acid levels were higher in the DCRC group than other groups ( P < 0.05). The correlation analysis showed that the dominant bacterial abundance in the DCRC group ( Parvimonas , Desulfurispora , Sebaldella , and Veillonellales , among others) was negatively correlated with butyric acid, hyodeoxycholic acid, ursodeoxycholic acid, glycochenodeoxycholic acid, chenodeoxycholic acid, cholic acid and glycocholate. However, the abundance of mostly inferior bacteria was positively correlated with these metabolic acid levels, including Faecalibacterium , Thermococci , and Cellulophaga . Unique fecal microbiome signatures exist in CRC patients with T2DM compared to those with non-diabetic CRC. Alterations in GM composition and SCFAs and secondary BAs levels may promote CRC development.

The value of bile acid spectrum in the evaluation of hepatic injury in children with infectious mononucleosis caused by Epstein Barr virus infection.

Infectious mononucleosis (IM) is an acute infectious disease, caused by Epstein-Barr virus (EBV) infection, which can invade various systemic systems, among which hepatic injury is the most common. In this study, ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to detect serum bile acid spectrum in IM children quantitatively, and to investigate its role in the early assessment of hepatic injury. This case-control study was conducted at Yuhuan People's Hospital. A total of 60 IM children and 30 healthy children were included in the study. Among 60 children with IM, 30 had hepatic injury, and 30 without hepatic injury. The clinical and laboratory data were analyzed, and the serum bile acid spectrum and lymphocyte subsets were evaluated in the three groups. There were statistically significant differences in cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), lithocholic acid (LCA), glycochenodeoxycholic acid (GCDCA), glycodeoxycholic acid(GDCA), glycolithocholic acid (GLCA), taurocholic acid (TCA), taurochenodeoxycholic acid (TCDCA), taurodeoxycholic acid (TDCA), ursodeoxycholic acid (UDCA), glycoursodeoxycholic acid (GUDCA), tauroursodeoxycholic acid(TUDCA), percentage of NK cells, CD4+ and CD8+ in IM hepatic injury group, without hepatic injury group, and the healthy control group (P < 0.05). The percentage of NK cells was positively correlated with TCA (P < 0.05); it was negatively correlated with CDCA, DCA, LCA, GCDCA, GDCA, GLCA, TDCA, UDCA, GUDCA, TUDCA (P < 0.05). CD4+ was positively correlated with CA, TCA and TCDCA (P < 0.05); it was negatively correlated with CDCA, DCA, LCA, GCDCA, GDCA, GLCA, TDCA, UDCA, GUDCA and TUDCA (P < 0.05). CD8+ was positively correlated with CDCA, DCA, LCA, GCDCA, GDCA, GLCA, TDCA, UDCA, GUDCA and TUDCA (P < 0.05); it was negatively correlated with CA, TCA and TCDCA (P < 0.05). ROC curve analysis showed that CD8+, GDCA and GLCA had high predictive value for hepatic injury in IM patients. UPLC-MS/MS method can sensitively detect the changes in serum bile acid spectrum before hepatic injury in children with IM, which is helpful for early assessment of hepatic injury in children with IM. The changes in lymphocyte subsets in IM children are related to some bile acid subfractions, which may be related to IM hepatic injury.

Modulation of the biological network of lumbar spinal stenosis by Tongdu Huoxue Decoction based on clinical metabolomics.

Objective: To explore the clinical efficacy and metabolic mechanism of Tongdu Huoxue Decoction (THD) in treating lumbar spinal stenosis (LSS). Methods: A total of 40 LSS patients and 20 healthy participants were recruited from January 2022 to June 2022. The patients' pre- and post-treatment visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) scores were recorded. ELISA kits were used to assess pre- and post-treatment levels of serum Interleukin-1beta (IL-1β), Alpha tumour necrosis factor (TNF-α) and prostaglandin E2 (PGE2). Finally, the patients' pre- and post-treatment and healthy human sera were subjected to extensively targeted metabolomics using Ultra Performance Liquid Chromatography (UPLC) to identify potential differential metabolites and metabolic pathways using multivariate statistical analysis. Results: Compared to the pre-treatment (group A), the patients' VAS scores decreased significantly (p < 0.05), while JOA scores increased significantly (p < 0.05) post-treatment (group B), indicating that THD could effectively improve the pain and lumbar spine function of LSS patients. Moreover, THD could effectively inhibit the expression of IL-1β, TNF-α and PGE2-associated inflammatory factors in serum. Regarding metabolomics, the levels of 41 differential metabolites were significantly different in the normal group (group NC) compared to group A, and those were significantly restored after treatment with THD, including chenodeoxycholic acid 3-sulfate, taurohyodeoxycholic acid, 3,5-Dihydroxy-4-methoxybenzoic acid, pinocembrin. These biomarkers are mainly involved in purine metabolism, steroid hormone biosynthesis and amino acid metabolism. Conclusion: This clinical trial demonstrated that THD is effective in improving pain, lumbar spine function and serum levels of inflammation in patients with LSS. Moreover, its mechanism of action is related to the regulation of purine metabolism, steroid hormone biosynthesis and the expression of key biomarkers in the metabolic pathway of amino acid metabolism.

Integrated analysis of serum untargeted metabolomics and targeted bile acid metabolomics for identification of diagnostic biomarkers for colorectal cancer

To identify potential diagnostic biomarkers of colorectal cancer (CRC) using serum metabolomic technology for minimally invasive and efficient screening for CRC. Serum samples from 79 healthy individuals and 82 CRC patients were analyzed by metabolomics using ultra-high-performance liquid chromatography-tandem highresolution mass spectrometry (UHPLC-HRMS). The differential metabolites between the two groups were analyzed using principal component analysis and orthogonal partial least squares discriminant analysis (OPLS-DA). Receiver operating characteristic curve (ROC) analysis was performed to identify the differential metabolites with good diagnostic performance (AUC>0.80) for CRC, and targeted bile acid metabolomics was used to verify the selected bile acids as biomarkers. Serum metabolic profiles differed significantly between the healthy individuals and CRC patients, and a total of 82 differential metabolites (mostly fatty acids and glycerophospholipids) were selected. ROC analysis identified 10 differential metabolites, including adenine, bilirubin, ACar 12:0, ACar 10:1, ACar 9:0, PC 18:2e, deoxycholic acid, chenodeoxycholic acid, ACar 14:1 and palmitoylcarnitine. One of these metabolites was significantly up-regulated and 9 were down-regulated in the serum of CRC patients (P < 0.05). Multivariate ROC analysis with support vector machine algorithm showed that the biomarker panel consisting of 7 differential metabolites had an AUC of 0.94 for CRC diagnosis. The results of targeted bile acid metabolomics were consistent with those of untargeted metabolomics. The serum levels of deoxycholic acid and chenodeoxycholic acid were significantly down-regulated in patients with CRC as compared with the healthy individuals (P < 0.05). Metabolic disorders of fatty acids and glycerophospholipids are closely related wigh tumorigenesis of CRC. Ten differential metabolites show good performance for CRC diagnosis, and the panel consisting 7 of these metabolites has important diagnostic value for CRC. Deoxycholic acid and chenodeoxycholic acid may serve as potential diagnostic biomarkers of CRC.

Characterization of gut microbial and metabolite alterations in faeces of Goto Kakizaki rats using metagenomic and untargeted metabolomic approach.

In recent years, the incidence of type 2 diabetes (T2DM) has shown a rapid growth trend. Goto Kakizaki (GK) rats are a valuable model for the study of T2DM and share common glucose metabolism features with human T2DM patients. A series of studies have indicated that T2DM is associated with the gut microbiota composition and gut metabolites. We aimed to systematically characterize the faecal gut microbes and metabolites of GK rats and analyse the relationship between glucose and insulin resistance. To evaluate the gut microbial and metabolite alterations in GK rat faeces based on metagenomics and untargeted metabolomics. Ten GK rats (model group) and Wistar rats (control group) were observed for 10 wk, and various glucose-related indexes, mainly including weight, fasting blood glucose (FBG) and insulin levels, homeostasis model assessment of insulin resistance (HOMA-IR) and homeostasis model assessment of β cell (HOMA-β) were assessed. The faecal gut microbiota was sequenced by metagenomics, and faecal metabolites were analysed by untargeted metabolomics. Multiple metabolic pathways were evaluated based on the differential metabolites identified, and the correlations between blood glucose and the gut microbiota and metabolites were analysed. The model group displayed significant differences in weight, FBG and insulin levels, HOMA-IR and HOMA-β indexes (P < 0.05, P < 0.01) and a shift in the gut microbiota structure compared with the control group. The results demonstrated significantly decreased abundances of Prevotella sp. CAG:604 and Lactobacillus murinus (P < 0.05) and a significantly increased abundance of Allobaculum stercoricanis (P < 0.01) in the model group. A correlation analysis indicated that FBG and HOMA-IR were positively correlated with Allobaculum stercoricanis and negatively correlated with Lactobacillus murinus. An orthogonal partial least squares discriminant analysis suggested that the faecal metabolic profiles differed between the model and control groups. Fourteen potential metabolic biomarkers, including glycochenodeoxycholic acid, uric acid, 13(S)-hydroxyoctadecadienoic acid (HODE), N-acetylaspartate, β-sitostenone, sphinganine, 4-pyridoxic acid, and linoleic acid, were identified. Moreover, FBG and HOMA-IR were found to be positively correlated with glutathione, 13(S)-HODE, uric acid, 4-pyridoxic acid and allantoic acid and ne-gatively correlated with 3-α, 7-α, chenodeoxycholic acid glycine conjugate and 26-trihydroxy-5-β-cholestane (P < 0.05, P < 0.01). Allobaculum stercoricanis was positively correlated with linoleic acid and sphinganine (P < 0.01), and 2-methyl-3-hydroxy-5-formylpyridine-4-carboxylate was negatively associated with Prevotella sp. CAG:604 (P < 0.01). The metabolic pathways showing the largest differences were arginine biosynthesis; primary bile acid biosynthesis; purine metabolism; linoleic acid metabolism; alanine, aspartate and glutamate metabolism; and nitrogen metabolism. Metagenomics and untargeted metabolomics indicated that disordered compositions of gut microbes and metabolites may be common defects in GK rats.

Rosmarinic Acid Restores Colonic Mucus Secretion in Colitis Mice by Regulating Gut Microbiota-Derived Metabolites and the Activation of Inflammasomes.

Maintaining a steady state of mucus barrier is an important potential target for polyphenol to exert its anticolitis activity. This study elucidates the pivotal role of polyphenol rosmaric acid (RA) in regulating the mucus barrier function and alleviating inflammation by identifying its gut microbiota-derived metabolites and evaluating its inhibitory effect on inflammasomes in colitis mice. Results demonstrated that RA treatment promoted the proliferation of goblet cells and restored the level of mucus secretion, especially Muc2. RA reshaped the microbiota of colitis mice, particularly the boost of core probiotics, such as p. Bacteroidaceae, f. Muribaculaceae, g. Muribaculaceae, g. Alistipes, and g. Clostridia_UCG-014. Nontargeted metabonomics and targeted metabonomics confirmed a significant increase in the bile acids and their metabolites (7-sulfocholic acid, stercobilin, chenodeoxycholic acid 3-sulfate, chenodeoxycholic acid sulfate, and ursodeoxycholic acid 3-sulfate), indole metabolites ((R)-2,3-dihydro-3,5-dihydroxy-2-oxo-3-indoleacetic acid, frovatriptan, 3-formyl-6-hydroxyindole, and brassicanal A), and short-chain fatty acids (SCFAs) (acetic acid, butyric acid, isobutyric acid, isovaleric acid, and valeric acid) that contributed to the strengthened mucus barrier function. In addition, being absorbed mainly in the lower digestive tract, RA inhibited the overexpression of inflammasomes (especially NLRP6) that occurred in colitis mice to promote the mucus secretion of goblet cells. These data confirmed that RA, as a promising candidate to enhance gut health, restored colonic mucus secretion in colitis mice by mediating the production of gut microbiota-derived metabolites and the overexpression of inflammasomes. The presented study provides scientific evidence explaining the apparent paradox of low bioavailability and high bioactivity in polyphenols.

Molecular determinants for differential activation of the bile acid receptor from the pathogen Vibrio parahaemolyticus

Bile acids are important for digestion of food and antimicrobial activity. Pathogenic Vibrio parahaemolyticus senses bile acids and induce pathogenesis. The bile acid taurodeoxycholate (TDC) was shown to activate the master regulator, VtrB, of this system, whereas other bile acids such as chenodeoxycholate (CDC) do not. Previously, VtrA-VtrC was discovered to be the co-component signal transduction system that binds bile acids and induces pathogenesis. TDC binds to the periplasmic domain of the VtrA-VtrC complex, activating a DNA-binding domain in VtrA that then activates VtrB. Here, we find that CDC and TDC compete for binding to the VtrA-VtrC periplasmic heterodimer. Our crystal structure of the VtrA-VtrC heterodimer bound to CDC revealed CDC binds in the same hydrophobic pocket as TDC but differently. Using isothermal titration calorimetry, we observed that most mutants in the binding pocket of VtrA-VtrC caused a decrease in bile acid binding affinity. Notably, two mutants in VtrC bound bile acids with a similar affinity as the WT protein but were attenuated for TDC-induced type III secretion system 2 activation. Collectively, these studies provide a molecular explanation for the selective pathogenic signaling by V.parahaemolyticus and reveal insight into a host's susceptibility to disease.

A174 A NOVEL MECHANISM OF CROHN’S DISEASE SEVERITY IN WOMEN: EVALUATING THE IMPACT OF AN ESTROGEN-FARNESOID X RECEPTOR INTERACTION ON INTESTINAL BARRIER FUNCTION

Abstract Background Crohn’s disease (CD) is associated with deficits in intestinal barrier function. Activation of bile acid-sensing nuclear receptor Farnesoid X receptor (NR1H4, FXR) is associated with protective effects against reduced intestinal barrier function; namely through promoting tight junction complex genes (TJCGs) and reducing expression of inflammatory cytokines. The FXR -1G&amp;gt;T variant is associated with decreased FXR activation and increased risk of, and early progression to, CD-related surgery in females only. It is hypothesized an estrogen-FXR interaction is mediating this effect. Purpose We aimed to assess the combined effect of estrogen and FXR genetic variation on intestinal barrier function using a cell-based model and its impact in a clinical cohort. Method Caco-2 cells were characterized for expression of TJCGs (zonula occludens-1, occludin, junctional adhesion molecule A, and claudin-1 and claudin-2), FXR, and nuclear estrogen receptors (ERα, ERβ) by qPCR. The influence of FXR activation on TJCGs was characterized by incubation of Caco-2 cells with chenodeoxycholic acid (CDCA). FXR-knockout stable Caco-2 line was developed using CRISPR-Cas9 methods and verified by qPCR and genotyping. The effect of estradiol on expression of TJCGs in FXR-knockout and wildtype Caco-2 cell monolayers was compared by qPCR. Future experiments include comparison of FXR-knockout and wildtype monolayer permeability with estrogen exposure by transwell permeability assay. The effect of FXR genotype and exogenous estrogen CD severity (surgery, hospitalization, fistulizing disease) was evaluated in our female cohort by multivariate analysis. Result(s) Increased expression of TJCGs was seen in native Caco-2 monolayers incubated with CDCA. FXR-knockout cell line was then successfully created and confirmed. FXR-knockout cells showed decreased expression of TJCGs with the exception of zonula occludens-1. Estradiol exposure resulted in a dose-dependent decline in TJCGs expression in the wildtype Caco-2 cell line, however this effect was lost in the FXR-knockout cell line. Preliminary analysis of patient cohort data (n=359) showed exogenous estrogen was associated with lower surgery risk (OR = 0.603, 95% CI= 0.373–0.964, p &amp;lt; 0.05; Fischer’s exact test) and trended towards decreasing fistulizing disease risk in a multiple logistic regression model which included FXR genotype. The association of FXR genotype with increased surgery risk was also confirmed in this logistic regression model. Conclusion(s) Herein, we show that FXR activity affects expression of TJCGs, and this effect is attenuated by estrogen interactions. Our patient cohort preliminary analysis confirmed an increased CD severity risk associated with FXR genotype and demonstrated a trend of decreasing CD severity with exogenous estrogen exposure. Further studies will assess the mechanisms by which FXR and estrogen interact to influence intestinal permeability. Please acknowledge all funding agencies by checking the applicable boxes below Other Please indicate your source of funding; Department of Medicine, Western University Disclosure of Interest D. Taylor: None Declared, L. Donovan: None Declared, J. Choi: None Declared, R. Kim: None Declared, U. Schwarz: None Declared, A. Wilson Consultant of: Consulting fees from Fresenius Kabi, Speakers bureau of: Speaking fees from Takeda and Pfizer

Defecation status, intestinal microbiota, and habitual diet are associated with the fecal bile acid composition: a cross-sectional study in community-dwelling young participants

PurposeBile acid (BA) metabolism by intestinal bacteria is associated with the risk of gastrointestinal diseases; additionally, its control has become a modern strategy for treating metabolic diseases. This cross-sectional study investigated the influence of defecation status, intestinal microbiota, and habitual diet on fecal BA composition in 67 community-dwelling young participants.MethodsFeces were collected for intestinal microbiota and BA analyses; data about defecation status and dietary habits were collected using the Bristol stool form scales and a brief-type self-administered diet history questionnaire, respectively. The participants were categorized into four clusters based on their fecal BA composition, according to cluster analysis, and tertiles based on deoxycholic acid (DCA) and lithocholic acid (LCA) levels.ResultsThe high primary BA (priBA) cluster with high fecal cholic acid (CA) and chenodeoxycholic acid (CDCA) levels had the highest frequency of normal feces, whereas the second BA (secBA) cluster with high levels of fecal DCA and LCA had the lowest. Alternately, the high-priBA cluster had a distinct intestinal microbiota, with higher Clostridium subcluster XIVa and lower Clostridium cluster IV and Bacteroides. The low-secBA cluster with low fecal DCA and LCA levels had the lowest animal fat intake. Nevertheless, the insoluble fiber intake of the high-priBA cluster was significantly higher than that of the high-secBA cluster.ConclusionHigh fecal CA and CDCA levels were associated with distinct intestinal microbiota. Conversely, high levels of cytotoxic DCA and LCA were associated with increased animal fat intake and decreased frequency of normal feces and insoluble fiber intake.Clinical trial registryUniversity Hospital Medical Information Network (UMIN) Center system (UMIN000045639); date of registration: 15/11/2019.