Pathway Of Bile Acid Biosynthesis Research Articles

Integrated serum metabolomics, 16S rRNA sequencing and bile acid profiling to reveal the potential mechanism of gentiopicroside against nonalcoholic steatohepatitis in lean mice

Ethnopharmacological relevanceLean nonalcoholic steatohepatitis (NASH) poses a serious threat to public health worldwide. Herbs of the genus Gentiana have been used for centuries to treat hepatic disease or have been consumed for hepatic protection efficiency. Gentiopicroside (GPS), the main bioactive component of Gentiana herbs, has been shown to be beneficial for protecting the liver, improving intestinal disorders, modulating bile acid profiles, ameliorating alcoholic hepatosteatosis, and so on. It is plausible to speculate that GPS may hold potential as a therapeutic strategy for lean NASH. However, no related studies have been conducted thus far. Aim of the studyThe present work aimed to investigate the benefit of GPS on NASH in a lean mouse model. Materials and methodsNASH in a lean mouse model was successfully established via a published method. GPS of 50 and 100 mg/kg were orally administered to verify the effect. Untargeted metabolomics, 16S rDNA sequencing and bile acid (BA) profiling, as well as qPCR and Western blotting analysis were employed to investigate the mechanism underlying the alleviating effect. ResultsGPS significantly reduced the increase in serum biochemicals and liver index, and attenuated the accumulation of fat in the livers of lean mice with NASH. Forty-two potential biomarkers were identified by metabolomics analysis, leading to abnormal metabolic pathways of primary bile acid biosynthesis and fatty acid biosynthesis, which were subsequently rebalanced by GPS. A decreased Firmicutes/Bacteroidetes (F/B) ratio and disturbed BA related GM profiles were revealed in lean mice with NASH but were partially recovered by GPS. Furthermore, serum profiling of 23 BAs confirmed that serum BA levels were elevated in the lean model but downregulated by GPS treatment. Pearson correlation analysis validated associations between BA profiles, serum biochemical indices and related GM. qPCR and Western blotting analysis further elucidated the regulation of genes associated with liver lipid synthesis and bile acid metabolism. ConclusionsGPS may ameliorate steatosis in lean mice with NASH, regulating the metabolomic profile, BA metabolism, fatty acid biosynthesis, and BA-related GM. All these factors may contribute to its beneficial effect.

Konjac supplementation can alleviate obesity induced by high-fat diet in mice by modulating gut microbiota and its metabolites

As a multi-factorial disease, obesity has become one of the major health problems in the world, and it is still increasing rapidly. Konjac supplementation, as a convenient dietary therapy, has been shown to be able to regulate gut microbiota and improve obesity. However, the specific mechanism by which konjac improves obesity through gut microbiota remains to be studied. In this study, a high-fat diet (HFD) was used to induce a mouse obesity model, and 16S rDNA sequencing and an untargeted metabolomics were used to investigate the impact of konjac on gut microbiota and gut metabolites in HFD-induced obese mice. The results show that konjac can reduce the body weight, adipose tissue weight, and lipid level of high-fat diet induced obese mice by changing the gut microbiota structure and gut metabolic profile. Association analysis revealed that konjac supplementation induced changes in gut microbiota, resulting in the up-regulation of 7-dehydrocholesterol and trehalose 6-phosphate, as well as the down-regulation of glycocholic acid and ursocholic acid within the Secondary bile acid biosynthesis pathway, ultimately leading to improvements in obesity. Among them, g_Acinetobacter (Greengene ID: 911888) can promote the synthesis of 7-dehydrocholesterol by synthesizing ERG3. g_Allobaculum (Greengene ID: 271516) and g_Allobaculum (Greengene ID: 259370) can promote the breakdown of trehalose 6-phosphate by synthesizing glvA. Additionally, the down-regulation of glycocholic acid and ursocholic acid may be influenced by the up-regulation of Lachnospiraceae_NK4A136_group. In conclusion, konjac exerts an influence on gut metabolites through the regulation of gut microbiota, thereby playing a pivotal role in alleviating obesity induced by a high-fat diet.

Microbiome and metabolome analyses reveal significant alterations of gut microbiota and bile acid metabolism in ETEC-challenged weaned piglets by dietary berberine supplementation.

This study mainly investigated the effects of berberine (BBR) on the bile acid metabolism in gut-liver axis and the microbial community in large intestine of weaned piglets challenged with enterotoxigenic Escherichia coli (ETEC) by microbiome and metabolome analyses. Sixty-four piglets were randomly assigned to four groups including Control group, BBR group, ETEC group, and BBR + ETEC group. Dietary BBR supplementation upregulated the colonic mRNA expression of Occludin, Claudin-5, trefoil factor 3 (TFF3), and interleukin (IL)-10, and downregulated colonic IL-1β and IL-8 mRNA expression in piglets challenged with ETEC K88 (p < 0.05). The hepatic non-targeted metabolome results showed that dietary BBR supplementation enriched the metabolic pathways of primary bile acid biosynthesis, tricarboxylic acid cycle, and taurine metabolism. The hepatic targeted metabolome analyses showed that BBR treatment increased the hepatic concentrations of taurocholic acid (TCA) and taurochenodeoxycholic acid (TDCA), but decreased the hepatic cholic acid (CA) concentration (p < 0.05). Further intestinal targeted metabolome analyses indicated that the deoxycholic acid (DCA), hyocholic acid (HCA), 7-ketodeoxycholic acid (7-KDCA), and the unconjugated bile acid concentrations in ileal mucosa was decreased by dietary BBR treatment (p < 0.05). Additionally, BBR treatment significantly upregulated the hepatic holesterol 7 α-hydroxylase (CYP7A1) and sterol 27-hydroxylase (CYP27A1) mRNA expression, and upregulated the ileal mRNA expression of farnesoid X receptor (FXR) and apical sodium-dependent bile acid transporter (ASBT) as well as the colonic mRNA expression of FXR, fibroblast growth factor19 (FGF19), takeda G protein-coupled receptor 5 (TGR5) and organic solute transporters beta (OST-β) in piglets (p < 0.05). Moreover, the microbiome analysis showed that BBR significantly altered the composition and diversity of colonic and cecal microbiota community, with the abundances of Firmicutes (phylum), and Lactobacillus and Megasphaera (genus) significantly increased in the large intestine of piglets (p < 0.05). Spearman correlation analysis showed that the relative abundances of Megasphaera (genus) were positively correlated with Claudin-5, Occludin, TFF3, and hepatic TCDCA concentration, but negatively correlated with hepatic CA and glycocholic acid (GCA) concentration (p < 0.05). Moreover, the relative abundances of Firmicute (phylum) and Lactobacillus (genus) were positively correlated with hepatic TCDCA concentration (p < 0.05). Collectively, dietary BBR supplementation could regulate the gut microbiota and bile acid metabolism through modulation of gut-liver axis, and attenuate the decreased intestinal tight junction expression caused by ETEC, which might help maintain intestinal homeostasis in weaned piglets.

Association of cord plasma metabolites with birth weight: results from metabolomic and lipidomic studies of discovery and validation cohorts.

Birth weight is a good predictor of fetal intrauterine growth and long-term health. Although several studies have evaluated the relationship between metabolites and birth weight, no prior study has comprehensively investigated the metabolomic and lipidomic and further validated and quantified meaningful metabolites. Firstly, a pseudotargeted metabolomics approach was applied to detect 2418 metabolites in 504 cord blood samples in the discovery set enrolled from the Wuhan Healthy Baby Cohort (HBC), China. Metabolome-wide association scan (MWAS) analysis and pathway enrichment were applied to discover metabolites and metabolic pathways that were significantly associated with birth weight for gestational age (BWGA) z-score. Logistic regression models were used to analyze the association of metabolites in the most significantly associated pathways with small for gestational age (SGA) and low birth weight (LBW). Subsequently, 350 cord blood samples in a validation cohort were subjected to targeted analysis to validate the metabolites screened from the discovery cohort. In the discovery set, 513 metabolites were significantly associated with BWGA z-score (PFDR <0.05), of which 298 KEGG-annotated metabolites were included in the pathway analysis. The primary bile acid biosynthesis pathway was the most relevant metabolic pathway associated with BWGA z-score in our study. Elevated cord plasma primary bile acids were associated with lower BWGA z-score and higher odds of SGA or LBW in the discovery and validation cohorts. In the validation set, a 2-fold increase in taurochenodeoxycholic acid (TCDCA) and taurocholic acid (TCA) was associated with 0.10 (95% CI: 0.00, 0.20) and 0.18 (95 %CI: 0.04, 0.31) decrease in BWGA z-score, respectively, after adjusting for covariates. In addition, a 2-fold increase in cord plasma TCDCA and TCA was associated with an adjusted odds ratio of 1.52 (1.00, 2.30) and 1.77 (1.05, 2.98) for SGA, respectively. The adjusted ORs for a 2-fold increase in TCDCA and TCA concentrations were 2.39 (95% CI 1.00, 5.71) and 3.21 (0.96, 10.74) for LBW, respectively. The results indicate a significant association between primary bile acids and lower BWGA z-score, as well as higher risk of SGA and LBW. Abnormalities of primary bile acid metabolism may play an important role in restricted fetal development. This article is protected by copyright. All rights reserved.

Transcriptomics and metabolomics reveal hypothalamic metabolic characteristics and key genes after subarachnoid hemorrhage in rats

Subarachnoid hemorrhage (SAH) is a serious hemorrhagic event with high mortality and morbidity. Multiple injurious events produced by SAH can lead to a series of pathophysiologic processes in the hypothalamus that can severely impact patients’ life. These pathophysiologic processes usually result in physiologic derangements and dysfunction of the brain and multiple organs. This dysfunction involved multiple dimensions of the genome and metabolome. In our study, we induced the SAH model in rats to obtain hypothalamic tissue and serum. The samples were subsequently analyzed by transcriptomics and metabolomics. Next, the functional enrichment analysis of the differentially expressed genes and metabolites were performed by GO and KEGG pathway analysis. Through transcriptomic analysis of hypothalamus samples, 263 up-regulated differential genes, and 207 down-regulated differential genes were identified in SAH groups compared to Sham groups. In the KEGG pathway analysis, a large number of differential genes were found to be enriched in IL-17 signaling pathway, PI3K-Akt signaling pathway, and bile secretion. Liquid chromatography-mass spectrometry metabolomics technology was conducted on the serum of SAH rats and identified 11 up-regulated and 26 down-regulated metabolites in positive ion model, and 1 up-regulated and 10 down-regulated metabolites in negative ion model. KEGG pathways analysis showed that differentially expressed metabolites were mainly enriched in pathways of bile secretion and primary bile acid biosynthesis. We systematically depicted the neuro- and metabolism-related biomolecular changes occurring in the hypothalamus after SAH by performing transcriptomics and metabolomics studies. These biomolecular changes may provide new insights into hypothalamus-induced metabolic changes and gene expression after SAH.

Effects of sn-2 Palmitic Triacylglycerols and the Ratio of OPL to OPO in Human Milk Fat Substitute on Metabolic Regulation in Sprague-Dawley Rats.

In this study, the influence of total sn-2 palmitic triacylglycerols (TAGs) and ratio of 1-oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL) to 1,3-dioleoyl-2-palmitoylglycerol (OPO) in human milk fat substitute (HMFS) on the metabolic changes were investigated in Sprague-Dawley rats. Metabolomics and lipidomics profiling analysis indicated that increasing the total sn-2 palmitic TAGs and OPL to OPO ratio in HMFS could significantly influence glycine, serine and threonine metabolism, glycerophospholipid metabolism, glycerolipid metabolism, sphingolipid metabolism, bile acid biosynthesis, and taurine and hypotaurine metabolism pathways in rats after 4 weeks of feeding, which were mainly related to lipid, bile acid and energy metabolism. Meanwhile, the up-regulation of taurine, L-tryptophan, and L-cysteine, and down-regulations of lysoPC (18:0) and hypoxanthine would contribute to the reduction in inflammatory response and oxidative stress, and improvement of immunity function in rats. In addition, analysis of targeted biochemical factors also revealed that HMFS-fed rats had significantly increased levels of anti-inflammatory factor (IL-4), immunoglobulin A (IgA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-px), and decreased levels of pro-inflammatory factors (IL-6 and TNF-α) and malondialdehyde (MDA), compared with those of the control fat-fed rats. Collectively, these observations present new in vivo nutritional evidence for the metabolic regulatory effects of the TAG structure and composition of human milk fat substitutes on the host.

Wallace melon juice fermented with Lactobacillus alleviates dextran sulfate sodium-induced ulcerative colitis in mice through modulating gut microbiota and the metabolism.

Fermented foods have shown promise in preventing or treating ulcerative colitis (UC) via regulating intestinal flora and correcting metabolic disorders. However, the prevention effect of fermented Wallace melon juice (FMJ) on UC is unclear. In this study, the effects of FMJ on dextran sodium sulfate (DSS)-induced UC were investigated via 16S rRNA sequencing and non-targeted metabolomics. The results showed that FMJ was effective in alleviating the symptoms of UC, reducing histological damage and oxidative stress, decreasing the levels of pro-inflammatory cytokines. After FMJ treatment, the level of propionic acid, butyric acid, and valeric acid increased by 14.1%, 44.4%, and 52.4% compared to DSS-induced UC mice. Meanwhile, the levels of harmful bacteria such as Oscillospira, Bacteroidetes, and Erysipelotrichaceae and Clostridium decreased, while the levels of beneficial bacteria such as Akkermansia, Lactobacillus, and Bifidobacterium increased. Fecal metabolomics analysis identified 31 differential metabolites, which could regulate metabolic disorders in UC mice by controlling the primary bile acid biosynthesis, purine metabolism, and pantothenate and CoA biosynthesis pathway. Additionally, the abundances of butyric acid, bile acids, and pantothenic acid were positively correlated with Allobaculum, Bifidobacterium, and other beneficial bacteria (R2>0.80, p<0.01). The results indicated that FMJ played a role in regulating the structure of intestinal flora, which in turn helped in repairing metabolic disorders and alleviated colitis inflammation.

Environmental Evaluation on Toxicity, Toxic Mechanism, and Hydrolysis Behavior of Potential Acethydrazide Fungicide Candidates.

The evaluation of toxicity and environmental behavior of bioactive lead molecules is helpful in providing theoretical support for the development of agrochemicals, in line with the sustainable development of the ecological environment. In previous work, some acethydrazide structures have been demonstrated to exhibit excellent and broad-spectrum fungicidal activity; however, its environmental compatibility needs to be further elucidated if it is to be identified as a potential fungicide. In this project, the toxicity of fungicidal acethydrazide lead compounds F51, F58, F72, and F75 to zebrafish was determined at 10 μg mL-1 and 1 μg mL-1. Subsequently, the toxic mechanism of compound F58 was preliminarily explored by histologic section and TEM observations, which revealed that the gallbladder volume of common carp treated with compound F58 increased, accompanied by a deepened bile color, damaged plasma membrane, and atrophied mitochondria in gallbladder cells. Approximately, F58-treated hepatocytes exhibited cytoplasmic heterogeneity, with partial cellular vacuolation and mitochondrial membrane rupture. Metabolomics analysis further indicated that differential metabolites were enriched in the bile formation-associated steroid biosynthesis, primary bile acid biosynthesis, and taurine and hypotaurine metabolism pathways, as well as in the membrane function-related glycerophospholipid metabolism, linolenic acid metabolism, α-linolenic acid metabolism, and arachidonic acid metabolism pathways, suggesting that the acethydrazide F58 may have acute liver toxicity to common carp. Finally, the hydrolysis dynamics of F58 was investigated, with the obtained half-life of 5.82 days. The above results provide important guiding significance for the development of new green fungicides.

Chronic blue light-emitting diode exposure harvests gut dysbiosis related to cholesterol dysregulation.

Night shift workers have been associated with circadian dysregulation and metabolic disorders, which are tightly coevolved with gut microbiota. The chronic impacts of light-emitting diode (LED) lighting at night on gut microbiota and serum lipids were investigated. Male C57BL/6 mice were exposed to blue or white LED lighting at Zeitgeber time 13.5-14 (ZT; ZT0 is the onset of "lights on" and ZT12 is the "lights off" onset under 12-hour light, 12-hour dark schedule). After 33 weeks, only the high irradiance (7.2 J/cm2) of blue LED light reduced the alpha diversity of gut microbiota. The high irradiance of white LED light and the low irradiance (3.6 J/cm2) of both lights did not change microbial alpha diversity. However, the low irradiance, but not the high one, of both blue and white LED illuminations significantly increased serum total cholesterol (TCHO), but not triglyceride (TG). There was no significant difference of microbial abundance between two lights. The ratio of beneficial to harmful bacteria decreased at a low irradiance but increased at a high irradiance of blue light. Notably, this ratio was negatively correlated with serum TCHO but positively correlated with bile acid biosynthesis pathway. Therefore, chronic blue LED lighting at a high irradiance may harvest gut dysbiosis in association with decreased alpha diversity and the ratio of beneficial to harmful bacteria to specifically dysregulates TCHO metabolism in mice. Night shift workers are recommended to be avoid of blue LED lighting for a long and lasting time.

Study on the hypotensive effect and mechanism of hawthorn (Crataegus pinnatifida) fruits and hyperoside in spontaneously hypertensive rats.

Hawthorn fruits have a sweet and sour taste, besides having beneficial therapeutic effects on hyperlipidemia, hypertension, and coronary heart disease, making them widely used in food and clinical medicine. However, their hypotensive effects and potential mechanisms of anti-hypertension still need to be elucidated. This study aims to explore the antihypertensive effect of hawthorn and its monomer hyperoside on spontaneously hypertensive rats through pharmacodynamics, serum metabolomics, and in vivo mechanism studies. After 7 weeks of intervention with hawthorn extract and hyperoside, the blood pressure was significantly reduced. Aortic vascular staining results showed that the injury was significantly improved after intervention with hawthorn extract and hyperoside. According to the serum metabolomics study, the main metabolic pathway regulating blood pressure in hawthorn extract and hyperoside groups was the primary bile acid biosynthesis pathway. Quantitative experiments confirmed that the level of bile acid in the model group was significantly different from that in the normal group, while that in the hawthorn group and the hyperoside group was close to that in the normal group. Based on the prediction of bile acid-hypertension related targets and the literature, nine genes involved in bile acid metabolism and inflammatory pathways were selected for further study. The FXR, TGR5, ET-1, NOS3, Akt1, TNF-α, Ptgs2, ACE2 and Kdr mRNA expression levels in the hawthorn extract and hyperoside groups were significantly different from those in the model groups. In summary, hawthorn extract and hyperoside have a hypotensive effect on spontaneously hypertensive rats through bile acid and inflammation related targets. Hence, hawthorn extract has the potential to become a functional food or an alternative therapy for hypertension.

Exploring the causal correlations between 486 serum metabolites and systemic lupus erythematosus: a bidirectional Mendelian randomization study.

Objective: The observational association between circulating metabolites and systemic lupus erythematosus (SLE) has been well documented. However, whether the association is causal remains unclear. In this study, bidirectional Mendelian randomization (MR) was introduced to analyse the causal relationships and possible mechanisms. Methods: We conducted a two-sample bidirectional MR study. A genome-wide association study (GWAS) with 7,824 participants provided data on 486 human blood metabolites. Outcome information was obtained from a large-scale GWAS summary, which contained 5,201 single nucleotide polymorphisms (SNPs) cases and 9,066 control cases of Europeans and yielded a total of 7,071,163 SNPs. The inverse variance weighted (IVW) model was recruited as the primary two-sample MR analysis approach, followed by sensitivity analyses such as the heterogeneity test, horizontal pleiotropy test, leave-one-out analysis, and linkage disequilibrium score (LDSC) regression. Results: In this study, we discovered that 24 metabolites belonging to the lipid, carbohydrate, xenobiotic and amino acid superpathways may increase the risk of SLE occurrence (p < 0.05). In addition, the metabolic disorders of 51 metabolites belonging to the amino acid, energy, xenobiotics, peptide and lipid superpathways were affected by SLE (p < 0.05). Palmitoleate belonging to the lipid superpathway and isobutyrylcarnitine and phenol sulfate belonging to the amino acid superpathway were factors with two-way causation. The metabolic enrichment pathway of bile acid biosynthesis was significant in the forward MR analysis (p = 0.0435). Linolenic acid and linoleic acid metabolism (p = 0.0260), betaine metabolism (p = 0.0314), and glycerolipid metabolism (p = 0.0435) were the significant metabolically enriched pathways in the reverse MR analysis. Conclusion: The levels of some specific metabolites may either contribute to the immune response inducing SLE, or they may be intermediates in the development and progression of SLE. These metabolites can be used as auxiliary diagnostic tools for SLE and for the evaluation of disease progression and therapeutic effects.

Integrating metabolomics, 16S rRNA sequencing, network pharmacology, and metorigin to explore the mechanism of Cinnamomi Cortex in treating chronic atrophic gastritis rats

BackgroundCinnamomi cortex called as Rougui (RG) in Chinese was a widely used food-medicine homology. RG has the potential to treat chronic atrophic gastritis (CAG), a disease with widespread impact in the Chinese population. PurposeThis study aimed to explore its mechanism against CAG based on amalgamated strategies. MethodsNetwork pharmacology was used to predict the potential effective components and the core targets of RG against CAG based on the comprehensive chemical characterization using UHPLC-Q/TOF MS (ultra high performance liquid chromatogramphy-quadrupole/time-of-flight mass spectrometry). The CAG animals model were further used to validate its pharmacodynamics, of which gut microbiota of caecal contents were analyzed by integrating metabolomics, 16S rRNA sequencing, Metorigin metabolite traceability analysis and molecular docking to explore its action mechanism. ResultsNetwork pharmacology firstly predicted the efficacy of RG was attributed to four effective components and seven targets. Metabolomics of caecal contents in CAG rats revealed primary bile acid biosynthesis was its targeted metabolic pathway associated with the metabolism of gut microbiota coupled with Metorigin traceability analysis. 16S rRNA sequencing showed that RG treated CAG by regulating the imbalance of gut microbiota. Molecular docking further confirmed that the effective components of RG could intervene with potential targets, metorigin analysis pathway, and key enzymes of gut microbiota metabolic pathways. ConclusionOur results proved that RG exerted favorable effect on CAG. The four active ingredients (quercetin, kaempferol, oleic acid, and (-)-epicatechin) of RG were the key to exert drug effect, which could targeted the core target of CAG, primary bile acid biosynthesis and intestinal flora metabolic pathways.

Therapeutic effect and mechanism of Mailuo Shutong Pills on posterior limb swelling caused by femur fracture in rats based on intestinal flora and intestinal metabolism

This study aimed to investigate the protective effect and underlying mechanism of Mailuo Shutong Pills(MLST) on posterior limb swelling caused by femur fracture in rats. The rats were randomly divided into a sham operation group, a model group, a low-dose MLST group(1.8 g·kg~(-1)·d~(-1)), a high-dose MLST group(3.6 g·kg~(-1)·d~(-1)), and a positive drug group(60 mg·kg~(-1)·d~(-1) Maizhiling Tablets). The femur in the sham operation group was exposed and the wound was sutured, while the other four groups underwent mechanical damage to cause femur fracture. The rats were treated with corresponding drugs by gavage 7 days before modeling and 5 days after modeling, while those in the sham operation group and the model group were given an equivalent dose of distilled water by gavage. Hematoxylin-eosin(HE) staining was used to detect the pathological injury of the posterior limb muscle tissues in rats, and the degree of hind limb swelling was measured. The enzyme-linked immunosorbent assay(ELISA) kit was used to detect the expression levels of interleukin-6(IL-6), interleukin-1β(IL-1β), and tumor necrosis factor-α(TNF-α) in the serum of rats in each group. The activity of superoxide dismutase(SOD), malondialdehyde(MDA), catalase(CAT), and glutathione peroxidase(GSH-Px) in rat serum was also measured. Western blot was used to detect the protein expression levels of heme oxygenase 1(HO-1), NAD(P)H quinone oxidoreductase 1(NQO1), and nuclear transcription factor E2-related factor 2(Nrf2) in rat posterior limb muscle tissues. The changes in the intestinal flora and intestinal metabolites in rats were detected by 16S rDNA sequencing and ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS), respectively, to explore the underlying mechanism of MLST in treating posterior limb swelling caused by femur fracture in rats. Compared with the model group, MLST significantly improved the degree of posterior limb swelling in rats, reduced the levels of serum inflammatory factors, and alleviated oxidative stress injury. The HE staining results showed that the inflammatory infiltration in the posterior limb muscle tissues of rats in the MLST groups was significantly improved. Western blot results showed that MLST significantly increased the protein expression of HO-1, NQO1, and Nrf2 in rat posterior limb muscle tissues compared with the model group. The 16S rDNA sequencing results showed that MLST improved the disorder of intestinal flora in rats after femur fracture. The UPLC-MS/MS results showed that MLST significantly affected the bile acid biosynthesis and metabolism pathway in the intestine after femur fracture, and the Spearman analysis confirmed that the metabolite deoxycholic acid involved in bile acid biosynthesis was positively correlated with the abundance of Turicibacter. The metabolite cholic acid was positively correlated with the abundance of Papilibacter, Staphylococcus, and Intestinimonas. The metabolite lithocholic acid was positively correlated with Papilibacter and Intestinimonas. The above results indicated that MLST could protect against the posterior limb swelling caused by femur fracture in rats. This protective effect may be achieved by improving the pathological injury of the posterior limb muscle, reducing the expression levels of inflammatory and oxidative stress-related factors in serum, reducing the oxidative injury of the posterior limb muscle, improving intestinal flora, and balancing the biosynthesis of bile acids in the intestine.

Gardenia extract protects against intrahepatic cholestasis by regulating bile acid enterohepatic circulation

Ethnopharmacological relevanceCholestasis is the main manifestation of cholestatic liver disease, which has a risk of progression to end-stage liver disease. Gardeniae Fructus is the dried fruit of Gardeniae jasminoides Ellis, a plant of the Rubiaceae family. Gardeniae Fructus has shown therapeutic potential in cholestasis-related liver diseases and it is generally believed that Gardeniae Fructus ameliorates cholestasis, which could be related to its influence on bile acids (BAs) metabolism. However, the specific targets of Gardeniae Fructus and its impact on enterohepatic circulation of BAs have not yet been fully elucidated. Aim of the studyTo systematically elucidate the mechanism by which Gardenia extract (GE, total iridoids in Gardeniae Fructus, which contains the predominant and characteristic phytoconstituents of Gardeniae Fructus) ameliorates alpha-naphthylisothiocyanate (ANIT)-induced cholestatic liver injury. Materials and methodsSprague-Dawley rats were orally administered water, obeticholic acid (OCA, 2 mg/kg), or GE (21 and 42 mg/kg) once daily for five days. On the third day, the model was established by administration of a single dose of ANIT (40 mg/kg) by oral gavage. Biochemical and pathological analyses, BA metabolomics, transcriptomics, and qRT-PCR were performed. ResultsThe profile of BAs in serum and liver confirmed that GE attenuated ANIT-induced acute cholestasis by affecting BA metabolism in a dose-dependent manner. Liver transcriptomic analysis indicated that GE mainly influenced the primary bile acid (PBA) biosynthesis and bile secretion pathways. GE mainly affected PBA biosynthesis in liver by upregulating Cyp8b1 gene expression, thereby significantly reducing the level of total bile acids (TBA). GE mainly promoted PBA excretion from liver into duodenum by upregulating Fxr and Oatp1 gene expression, thereby increasing the excretion of PBA in feces, and inhibiting PBA in liver entering the blood by alternative routes to reduce TBA levels in serum and urine and improve the enterohepatic circulation of BAs. ConclusionGE attenuated ANIT-induced hepatotoxicity and cholestasis in rats by upregulating Cyp8b1 expression to inhibit BA synthesis in the liver, while also promoting BA excretion via the intestinal-fecal route, and improving enterohepatic circulation of BAs.

Huangqi Jianzhong Tang treats chronic atrophic gastritis rats by regulating intestinal flora and conjugated bile acid metabolism.

Huangqi Jianzhong Tang (HQJZ) is effective for treating chronic atrophic gastritis (CAG). The present study was carried out to reveal the mechanism of HQJZ in CAG rats. The metabolism and microbial composition of the cecal contents in CAG rats were analyzed through the integration of an untargeted metabolomic approach using ultra-high-performance liquid chromatography coupled with the quadrupole-time of flight mass spectrometry (UHPLC-QTOF-MS) and 16S rRNA gene sequencing, respectively. Finally, MetOrigin analyses were performed to explore the relationship between differential metabolites and intestinal flora. The results showed that HQJZ could significantly regulate metabolic disorders, especially conjugated acid metabolites. 16S rRNA gene sequencing analysis illustrated that HQJZ decreased the abundance of Acetobacter, Desulfovibrio, Escherichia, and Shigella. MetOrigin metabolite traceability analysis showed that the six bile acids associated with HQJZ efficacy included three bacteria-host cometabolites, which were involved in the primary bile acid biosynthesis pathway. Research presented here confirmed that conjugated bile acid metabolism was key to the treatment of CAG by HQJZ and correlates strongly with Bacteroides acidifaciens and Prevotella copri. These findings provide new insights into the mechanisms to explain the efficacy of HQJZ.

Lactobacillus gasseri LA39 promotes hepatic primary bile acid biosynthesis and intestinal secondary bile acid biotransformation.

A growing body of evidence has linked the gut microbiota to liver metabolism. The manipulation of intestinal microflora has been considered as a promising avenue to promote liver health. However, the effects of Lactobacillus gasseri LA39, a potential probiotic, on liver metabolism remain unclear. Accumulating studies have investigated the proteomic profile for mining the host biological events affected by microbes, and used the germ-free (GF) mouse model to evaluate host-microbe interaction. Here, we explored the effects of L. gasseri LA39 gavage on the protein expression profiles of the liver of GF mice. Our results showed that a total of 128 proteins were upregulated, whereas a total of 123 proteins were downregulated by treatment with L. gasseri LA39. Further bioinformatics analyses suggested that the primary bile acid (BA) biosynthesis pathway in the liver was activated by L. gasseri LA39. Three differentially expressed proteins (cytochrome P450 family 27 subfamily A member 1 (CYP27A1), cytochrome P450 family 7 subfamily B member 1 (CYP7B1), and cytochrome P450 family 8 subfamily B member 1 (CYP8B1)) involved in the primary BA biosynthesis pathway were further validated by western blot assay. In addition, targeted metabolomic analyses demonstrated that serum and fecal β‍-muricholic acid (a primary BA), dehydrolithocholic acid (a secondary BA), and glycolithocholic acid-3-sulfate (a secondary BA) were significantly increased by L. gasseri LA39. Thus, our data revealed that L. gasseri LA39 activates the hepatic primary BA biosynthesis and promotes the intestinal secondary BA biotransformation. Based on these findings, we suggest that L. gasseri LA39 confers an important function in the gut‒liver axis through regulating BA metabolism.

Alternative pathway of bile acid biosynthesis contributes to ameliorate NASH after induction of NAMPT/NAD+/SIRT1 axis

Non-alcoholic steatohepatitis (NASH) is emerging as a serious liver disorder characterized by hepatic steatosis and liver inflammation. Nicotinamide adenine dinucleotide (NAD+) and NAD+-dependent deacetylase, SIRT1, play important roles in lipid metabolism in non-alcoholic fatty liver disease (NAFLD). However, their effects on liver inflammation and homeostasis of bile acids (BAs), the extensively proved pathophysiological actors in NASH, have not been fully understood. NASH animal model was induced by a methionine-choline-deficient (MCD) diet in C57BL/6J mice and intraperitoneally injected with NAD+ precursor, an agonist of upstream rate-limiting enzyme NAMPT or downstream SIRT1, or their vehicle solvents. Free fatty acid (FFA) was applied to HepG2 cells to construct the cell model. Induction of NAMPT/NAD+/SIRT1 axis could remarkably alleviate the aggravated inflammation in the liver of NASH mice, accompanied by decreased levels of total BAs throughout the enterohepatic system and a switch of BA synthesis from the classic pathway to the alternative pathway, resulting in less production of pro-inflammatory 12-OH BAs. The expressions of key enzymes including cyp7a1, cyp8b1, cyp27a1 and cyp7b1 in BA synthesis were significantly modulated after NAMPT/NAD+/SIRT1 axis induction in both animal and cell models. The levels of pro-inflammatory cytokines in liver were significantly negatively correlated with the intermediates in NAD+ metabolism, which may also be related to their regulation on BA homeostasis. Our results indicated that induction of NAMPT/NAD+/SIRT1 axis may be a potential therapeutic strategy for NASH or its complications related with BAs.

Plasma metabolomics identifies metabolic alterations associated with the growth and development of cat.

The purpose of our study was to study the composition and content of the feline plasma metabolome revealing the critical metabolites and metabolic pathways associated with age during growth and development. Blood samples were collected from juvenile and adult groups for blood routine tests and serum biochemistry tests. Non-targeted metabolomics analyses of plasma were also performed to investigate changes in metabolites and metabolic pathways. In this study, we found that the red blood cell counts, liver function indexes (albumin and gamma-glutamyl transpeptidase), and the concentration of triglyceride and glucose changed significant with growth and development. The metabolomics results revealed that 1427 metabolites were identified in the plasma of young and adult cats. Most of these metabolites belong to major classes of lipids and lipid-like molecules. The most obvious age-related metabolites include reduced levels of chenodeoxycholate, taurocholate, cholate, and taurochenodeoxycholate but increased levels of L-cysteine and taurocyamine in the adult cat's serum. These metabolites are mainly involved in the primary bile acid biosynthesis pathway, the bile secretion pathway, and the taurine and hypotaurine metabolism pathway. This study revealed many age-related metabolite alterations in the feline plasma. These age-varying metabolites, especially in the bile acid biosynthesis and secretion metabolism pathways, indicate that the regulation of these pathways is involved in the growth and development of cats. This study promotes our understanding of the mechanism of feline growth and provides new insights into nutrition and medicine for cats of different ages.

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.

Cholestasis impairs gut microbiota development and bile salt hydrolase activity in preterm neonates

ABSTRACT Cholestasis refers to impaired bile flow from the liver to the intestine. In neonates, cholestasis causes poor growth and may progress to liver failure and death. Normal bile flow requires an intact liver-gut-microbiome axis, whereby liver-derived primary bile acids are transformed into secondary bile acids. Microbial bile salt hydrolase (BSH) enzymes are responsible for the first step, deconjugating glycine- and taurine-conjugated primary bile acids. Cholestatic neonates often are treated with the potent choleretic bile acid ursodeoxycholic acid (UDCA), although interactions between UDCA, gut microbes, and other bile acids are poorly understood. To gain insight into how the liver-gut-microbiome axis develops in extreme prematurity and how cholestasis alters this maturation, we conducted a nested case-control study collecting 124 stool samples longitudinally from 24 preterm infants born at mean 27.2 ± 1.8 weeks gestation and 946 ± 249.6 g, half of whom developed physiologic cholestasis. Samples were analyzed by whole metagenomic sequencing, in vitro BSH enzyme activity assays optimized for low biomass fecal samples, and quantitative mass spectrometry to measure the bile acid metabolome. In extremely preterm neonates, acquisition of the secondary bile acid biosynthesis pathway and BSH genes carried by Clostridium perfringens are the most prominent features of early microbiome development. Cholestasis interrupts this developmental pattern. BSH gene abundance and enzyme activity are profoundly reduced in cholestatic neonates, resulting in decreased quantities of unconjugated bile acids. UDCA restores total fecal bile acid levels in cholestatic neonates, but this is due to a 522-fold increase in fecal UDCA. A majority of bile acids in early development are atypical positional and stereo-isomers of bile acids. We report novel associations linking isomeric bile acids and BSH activity to neonatal growth trajectories. These data highlight deconjugation of bile acids as a key microbial function that is acquired in early neonatal development and impaired by cholestasis.