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Objective To explore the regulatory effect of Tangning Ziyabitus tablets (TZT) on the Christensenella minuta-taurine-α-muricholate (TαMCA)-farnesoid X receptor (FXR)/G protein-coupled receptor 5 axis based on a high-glucose human colorectal adenocarcinoma cell model. Methods The liquid medium for strains, high-glucose medium, TZT solution and TαMCA solution were prepared. The strains were cultured. Inactivated Christensenella minuta and its fermentation broth were prepared. Human colorectal adenocarcinoma cells (Caco-2 cells) were routinely cultured. Some cells were randomly divided into the control group, the inactivated bacteria group, 106 CFU/mL live bacteria group, 107 CFU/mL live bacteria group, 108 CFU/mL live bacteria group and 109 CFU/mL live bacteria group, respectively. The control group was cultured with sterile Caco-2 special medium. The inactivated bacteria group was intervened with inactivated Christensenella minuta bacterial suspension. The 106 CFU/mL live bacteria group, 107 CFU/mL live bacteria group, 108 CFU/mL live bacteria group and 109 CFU/mL live bacteria group were intervened by adding 2 mL of 109 CFU, 108 CFU, 107 CFU and 106 CFU of live Christensenella minuta bacteria to the wells of the culture plate containing completely differentiated Caco-2 cells, respectively. Some cells were randomly divided into the control group and fermentation broth group. The control group was cultured with sterile Caco-2 special medium, and the fermentation broth group was intervened with the fermentation broth of Christensenella minuta. Some cells were randomly divided into the control group, high-glucose group and low-, medium-, medium-to-high- and high-dose TZT groups. Except the control group, the other groups were intervened by adding 8 g/L high-glucose medium for 24 h. The low-, medium-, medium-to-high- and high-dose TZT groups were intervened by adding 10, 25, 50 and 100 µg/mL TZT drug-containing medium for 24 h. Some cells were randomly divided into the control group, 25 µmol/L TαMCA group and 50 µmol/L TαMCA group, respectively. The latter two groups were intervened by adding 25 and 50 µmol/L TαMCA-containing medium for 24 h. The expression levels of FXR, TGR5, IL-8 and IL-10 mRNA were detected by real-time fluorescent quantitative PCR, and the expression levels of FXR and TGR5 proteins were detected by Western blotting. Results Compared with the control group, the 106 CFU/mL live bacteria group, 107 CFU/ mL live bacteria group, 108 CFU/mL live bacteria group and 109 CFU/mL live bacteria group had higher levels of TGR5 mRNA expression (all P<0. 05), while there were no statistically significant differences in the FXR, IL-8 or IL-10 mRNA expression levels (all P>0. 05). Compared with the control group, the bacterial fermentation broth group had higher expression of FXR mRNA (all P<0. 05), and there was no statistically significant difference in the expression of TGR5 mRNA (P> 0. 05). Compared with the control group, the high-glucose group had higher expression of FXR mRNA (P<0. 05), and lower expression of TGR5 mRNA (P<0. 05); there were no statistically significant differences in the expression levels of FXR or TGR5 proteins (all P>0. 05). Compared with the high-glucose group, each TZT group had lower expression of FXR mRNA (all P<0. 05), and higher expression of TGR5 mRNA (all P<0. 05); there were no statistically significant differences in the expression levels of FXR or TGR5 proteins (all P>0. 05). Compared with the control group, in the 25 µmol/L TαMCA group, the expression levels of FXR mRNA and protein were lower (both P<0. 05), and the expression levels of TGR5 mRNA and protein were higher (both P<0. 05); in the 50 µmol/L TαMCA group, the expression of FXR protein was lower (P<0. 05). Conclusions Christensenella minuta has a certain anti-inflammatory effect. TZT may promote the growth of Christensenella minuta and produce metabolites that affect bile acid metabolism, promote the accumulation of TαMCA in the intestine, further inhibit the expression of intestinal FXR and promote the expression of TGR5. [ABSTRACT FROM AUTHOR]

Dietary lipid absorption is facilitated by bile acids. In the Zucker rat (ZR) model of obesity, bile acid absorption, mediated by the apical sodium bile acid transporter (ASBT), was increased in villus cells from the distal ileum. However, whether ASBT may be de novo expressed more proximally in the small intestine during obesity to facilitate additional bile acid absorption is not known. For this, starting from the end of the ileum to the mid jejunum, caudal-orally, five intestinal segments of equal length (S1–S5) were separated from lean and obese ZRs (LZR and OZR). Intestinal mucosa obtained from these segments were used for total RNA extraction, RT-qPCR and 3H-TCA uptake. The results showed that bile acid absorption along with the mRNA expression of ASBT and FXR progressively decreased caudal-orally in both LZRs and OZRs but was significantly higher in all small intestinal segments in OZRs. The expression of GATA4 was absent in the distal ileum (S1) in both LZRs and OZRs, but steadily increased along the proximal length in both. However, this steady increase was significantly reduced in the comparative obese proximal intestinal segments S2, S3, S4 and S5. The expressions of bile acid-activated G-protein-coupled bile acid receptor TGR5 and S1PR2 were unaltered in segments S1–S4 but were significantly increased in OZR S5. The paradigm changing observation of this study is that ASBT is expressed more proximally in the small intestine in obesity. This likely increases overall bile acid absorption and thereby lipid absorption in the proximal small intestine in obesity. [ABSTRACT FROM AUTHOR]

Total parenteral nutrition (TPN) provides lifesaving nutritional support intravenously; however, it is associated with significant side effects. Given gut microbial alterations noted with TPN, we hypothesized that transferring fecal microbiota from healthy controls would restore gut-systemic signaling in TPN and mitigate injury. Using our novel ambulatory model (US Patent: US 63/136,165), 31 piglets were randomly allocated to enteral nutrition (EN), TPN only, TPN + antibiotics (TPN-A), or TPN + intraduodenal fecal microbiota transplant (TPN + FMT) for 14 days. Gut, liver, and serum were assessed through histology, biochemistry, and qPCR. Stool samples underwent 16 s rRNA sequencing. Permutational multivariate analysis of variance, Jaccard, and Bray–Curtis metrics were performed. Significant bilirubin elevation in TPN and TPN-A versus EN (P < 0.0001) was prevented with FMT. IFN-G, TNF-α, IL-β, IL-8, and lipopolysaccharide (LPS) were significantly higher in TPN (P = 0.009, P = 0.001, P = 0.043, P = 0.011, P < 0.0001), with preservation upon FMT. Significant gut atrophy by villous-to-crypt ratio in TPN (P < 0.0001) and TPN-A (P = 0.0001) versus EN was prevented by FMT (P = 0.426 vs. EN). Microbiota profiles using principal coordinate analysis demonstrated significant FMT and EN overlap, with the largest separation in TPN-A followed by TPN, driven primarily by Firmicutes and Fusobacteria. TPN-altered gut barrier was preserved upon FMT; upregulated cholesterol 7 α-hydroxylase and bile salt export pump in TPN and TPN-A and downregulated fibroblast growth factor receptor 4, EGF, farnesoid X receptor, and Takeda G Protein-coupled Receptor 5 (TGR5) versus EN was prevented by FMT. This study provides novel evidence of prevention of gut atrophy, liver injury, and microbial dysbiosis with intraduodenal FMT, challenging current paradigms into TPN injury mechanisms and underscores the importance of gut microbes as prime targets for therapeutics and drug discovery. NEW & NOTEWORTHY: Intraduodenal fecal microbiota transplantation presents a novel strategy to mitigate complications associated with total parenteral nutrition (TPN), highlighting gut microbiota as a prime target for therapeutic and diagnostic approaches. These results from a highly translatable model provide hope for TPN side effect mitigation for thousands of chronically TPN-dependent patients. [ABSTRACT FROM AUTHOR]

The tolerance of Saccharomyces cerevisiae to high concentrations of bile acids is intricately linked to its potential as a probiotic. While the survival of yeast under high concentrations of bile acids has been demonstrated, the specific mechanisms of tolerance remain inadequately elucidated. This study aims to elucidate the tolerance mechanisms of S. cerevisiae CEN.PK2-1C under conditions of elevated bile acid concentrations. Through growth curve analyses and scanning electron microscopy (SEM), we examined the impact of high bile acid concentrations on yeast growth and cellular morphology. Additionally, transcriptomic sequencing and molecular docking analyses were employed to explore differentially expressed genes under high bile acid conditions, with particular emphasis on ATP-binding cassette (ABC) transporters and steroid hormone biosynthesis. Our findings indicate that high concentrations of bile acids induce significant alterations in the sterol synthesis pathway and transporter protein expression in S. cerevisiae. These alterations primarily function to regulate sterol synthesis pathways to maintain cellular structure and sustain growth, while enhanced expression of transport proteins improves tolerance to elevated bile acid levels. This study elucidates the tolerance mechanisms of S. cerevisiae under high bile acid conditions and provides a theoretical foundation for optimizing fermentation processes and process control. [ABSTRACT FROM AUTHOR]

Oleanolic acid (OA) is a naturally occurring pentacyclic triterpene compound that has been reported to cause cholestatic liver injury. However, the regulation and pathogenic role of bile acids in OA‐induced development of cholestatic liver injury remains largely unclear. Farnesoid X receptor (FXR) is a metabolic nuclear receptor that plays an important role in bile acid homeostasis in the liver by regulating efflux transporters bile salt export pump (BSEP) and multidrug resistance‐associated protein 2 (MRP2). The aim of this study was to investigate the effect of OA on hepatocyte tight junction function and determine the role of FXR, BSEP, and MRP2 in the mechanism of impairment of transport of bile acids induced by OA. Both in vivo and in vitro models were used to characterize the OA‐induced liver injury. The liquid chromatography–tandem mass spectrometry (LC‐MS) was employed to characterize the efflux function of the transporters, and the results showed that OA caused a blockage of bile acids efflux. OA treatment resulted in decreased expression levels of the tight junction proteins zonula occludens‐1 and occludin. Immunofluorescence results showed that OA treatment significantly reduced the number of bile ducts and the immunofluorescence intensity. Pretreatment with agonists of FXR and MRP2, respectively, in animal experiments attenuated OA‐induced liver injury, while pretreatment with inhibitors of BSEP and MRP2 further aggravated OA‐induced liver injury. These results suggest that OA inhibits FXR‐mediated BSEP and MRP2, leading to impaired bile acid efflux and disruption of tight junctions between liver cells, resulting in liver damage. Oleanolic acid (OA) is a naturally occurring pentacyclic triterpene compound that has been reported to cause cholestatic liver injury. In this study, OA inhibits FXR‐mediated BSEP and MRP2, leading to impaired bile acid efflux and disruption of tight junctions between liver cells, resulting in liver damage. Activation of FXR and MRP2 mitigated OA‐induced liver injury, while inhibition of BSEP and MRP2 further aggravated OA‐induced liver injury. [ABSTRACT FROM AUTHOR]

In recent years, with the rapid development of omics technologies, researchers have shown that interactions between the intestinal flora and bile acids are closely related to the progression of diabetic kidney disease (DKD). By regulating bile acid metabolism and receptor expression, the intestinal flora affects host metabolism, impacts the immune system, and exacerbates kidney injury in DKD patients. To explore interactions among the gut flora, bile acids and DKD, as well as the related mechanisms, in depth, in this paper, we review the existing literature on correlations among the gut flora, bile acids and DKD. This review also summarizes the efficacy of bile acids and their receptors as well as traditional Chinese medicines in the treatment of DKD and highlights the unique advantages of bile acid receptors in DKD treatment. This paper is expected to reveal a new and important potential strategy for the clinical treatment of DKD. [ABSTRACT FROM AUTHOR]

Hepatic lipid metabolism is regulated by the autonomic nervous system of the liver, with the sympathetic innervation being extensively studied, while the parasympathetic efferent innervation is less understood despite its potential importance. In this study, we investigate the consequences of disrupted brain–liver communication on hepatic lipid metabolism in mice exposed to obesogenic conditions. We found that a subset of hepatocytes and cholangiocytes are innervated by parasympathetic nerve terminals originating from the dorsal motor nucleus of the vagus. The elimination of the brain–liver axis by deleting parasympathetic cholinergic neurons innervating the liver prevents hepatic steatosis and promotes browning of inguinal white adipose tissue (ingWAT). The loss of liver-innervating cholinergic neurons increases hepatic Cyp7b1 expression and fasting serum bile acid levels. Furthermore, knockdown of the G protein-coupled bile acid receptor 1 gene in ingWAT reverses the beneficial effects of the loss of liver-innervating cholinergic neurons, leading to the reappearance of hepatic steatosis. Deleting liver-innervating cholinergic neurons has a small but significant effect on body weight, which is accompanied by an increase in energy expenditure. Taken together, these data suggest that targeting the parasympathetic cholinergic innervation of the liver is a potential therapeutic approach for enhancing hepatic lipid metabolism in obesity and diabetes. The liver autonomic nervous system is regulated by hepatic lipid metabolism. This study shows that a subset of hepatocytes and cholagiocytes are innervated by nerve terminals originating from the dorsal motor nucleus of the vagus nerve in high-fat diet fed mice and ablation of these cholinergic neurons could prevent hepatic steatosis. [ABSTRACT FROM AUTHOR]

The editorial discusses the advancements in microscopy and imaging techniques in plant and algal research, highlighting the importance of these tools in studying biological processes. The use of live-cell imaging combined with superresolution techniques allows for the observation of dynamic events at a resolution unachievable by traditional methods. Multiscale and multimodal imaging techniques provide a comprehensive analysis of samples, offering unique insights into biological mechanisms. The integration of chemical imaging techniques like MALDI-MSI can further enhance research in plant and organ studies by providing spatially resolved metabolite composition information. [Extracted from the article]

Obesity and type 2 diabetes (T2D) are widespread metabolic disorders that significantly impact global health today, affecting approximately 17% of adults worldwide with obesity and 9.3% with T2D. Both conditions are closely linked to disruptions in lipid metabolism, where peroxisomes play a pivotal role. Mitochondria and peroxisomes are vital organelles responsible for lipid and energy regulation, including the β-oxidation and oxidation of very long-chain fatty acids (VLCFAs), cholesterol biosynthesis, and bile acid metabolism. These processes are significantly influenced by estrogens, highlighting the interplay between these organelles' function and hormonal regulation in the development and progression of metabolic diseases, such as obesity, metabolic dysfunction-associated fatty liver disease (MAFLD), and T2D. Estrogens modulate lipid metabolism through interactions with nuclear receptors, like peroxisome proliferator-activated receptors (PPARs), which are crucial for maintaining metabolic balance. Estrogen deficiency, such as in postmenopausal women, impairs PPAR regulation, leading to lipid accumulation and increased risk of metabolic disorders. The disruption of peroxisomal–mitochondrial function and estrogen regulation exacerbates lipid imbalances, contributing to insulin resistance and ROS accumulation. This review emphasizes the critical role of these organelles and estrogens in lipid metabolism and their implications for metabolic health, suggesting that therapeutic strategies, including hormone replacement therapy, may offer potential benefits in treating and preventing metabolic diseases. [ABSTRACT FROM AUTHOR]

Liver inflammation is frequently linked to oxidative stress and dysregulation of bile acid and fatty acid metabolism. This review focuses on the farnesoid X receptor (FXR), a critical regulator of bile acid homeostasis, and its interaction with the nuclear factor erythroid 2-related factor 2 (Nrf2), a key modulator of cellular defense against oxidative stress. The review explores the interplay between FXR and Nrf2 in liver inflammatory diseases, highlighting the potential therapeutic effects of natural FXR agonists. Specifically, compounds such as auraptene, cafestol, curcumin, fargesone A, hesperidin, lycopene, oleanolic acid, resveratrol, rutin, ursolic acid, and withaferin A are reviewed for their ability to modulate both the FXR and Nrf2 pathways. This article discusses their potential to alleviate liver inflammation, oxidative stress, and damage in diseases such as metabolic-associated fatty liver disease (MAFLD), cholestatic liver injury, and viral hepatitis. In addition, we address the molecular mechanisms driving liver inflammation, including oxidative stress, immune responses, and bile acid accumulation, while also summarizing relevant experimental models. This review emphasizes the promising therapeutic potential of targeting both the Nrf2 and FXR pathways using natural compounds, paving the way for future treatments for liver diseases. Finally, the limitations of the clinical application were indicated, and further research directions were proposed. [ABSTRACT FROM AUTHOR]

Primary sclerosing cholangitis (PSC) is a rare, chronic liver disease with no approved therapies. The ursodeoxycholic acid (UDCA) has been widely used, although there is no evidence that the use of UDCA delays the time to liver transplant or increases survival. Several candidate drugs are currently being developed. The largest group of these new agents is represented by FXR agonists, including obeticholic acid, cilofexor, and tropifexor. Other agents that target bile acid metabolism are ASTB/IBAP inhibitors and fibroblasts growth factor (FGF)19 analogues. Cholangiocytes, the epithelial bile duct cells, play a role in PSC development. Recent studies have revealed that these cells undergo a downregulation of GPBAR1 (TGR5), a bile acid receptor involved in bicarbonate secretion and immune regulation. Additional agents under evaluation are PPARs (elafibranor and seladelpar), anti-itching agents such as MAS-related G-protein–coupled receptors antagonists, and anti-fibrotic and immunosuppressive agents. Drugs targeting gut bacteria and bile acid pathways are also under investigation, given the strong link between PSC and gut microbiota. [ABSTRACT FROM AUTHOR]

Cholestasis refers to a physiological and pathological process caused by bile acid (BA) overaccumulation inside the circulatory system and liver, leading to systemic and hepatocellular damage. Activating the farnesol X receptor (FXR) to restore BA homeostasis is a promising strategy for treating cholestasis. The objective of this research is to reveal solid evidence for the fact that the total iridoid glycosides from Swertia mussotii Franch. (IGSM) alleviate cholestasis. In this research, the whole plant of S. mussotii was extracted with 70% ethanol and separated by macroporous adsorption resin. A rat cholestasis model was established by the injection of α-naphthyl isothiocyanate (ANIT) at a dose of 75 mg/kg. Biochemical and oxidative stress indicators were determined using commercial assay kits. The mRNA abundance of FXR and target proteins was assessed using RT-qPCR. In addition, the effects of main compounds with FXR were evaluated by molecular docking after IGSM analysis using UPLC. The results indicated that IGSM alleviated ANIT-induced cholestasis through reducing serum ALT, AST, AKP, and TBA levels; increasing the mRNA levels of Fxr, Besp, Ntcp, and Mep2; and reducing oxidative stress. The proportion of iridoid compounds in IGSM exceeded 50%, which may be the active substance basis of IGSM. This study provides a theoretical reference for IGSM in the treatment of cholestasis, and future studies may delve more deeply into the FXR regulatory pathway. [ABSTRACT FROM AUTHOR]

Aim: Bile acids (BA) function as signalling molecules regulating glucose‐lipid homeostasis and energy expenditure. However, the expression of the apical sodium‐dependent bile acid transporter (ASBT) in the kidney, responsible for renal BA reabsorption, is downregulated in patients with diabetic kidney disease (DKD). Using the db/db mouse model of DKD, this study aimed to investigate the effects of rescuing ASBT expression via adeno‐associated virus‐mediated delivery of ASBT (AAVASBT) on kidney protection. Methods: Six‐week‐old male db/db mice received an intraparenchymal injection of AAVASBT at a dose of 1 × 1011 viral genomes (vg)/animal and were subsequently fed a chow diet for 2 weeks. Male db/m mice served as controls. For drug treatment, daily intraperitoneal (i.p.) injections of the farnesoid X receptor (FXR) antagonist guggulsterone (GS, 10 mg/kg) were administered one day after initiating the experiment. Results: AAVASBT treatment rescued renal ASBT expression and reduced the urinary BA output in db/db mice. AAVASBT treatment activated kidney mitochondrial biogenesis and ameliorated renal impairment associated with diabetes by activating FXR. In addition, the injection of FXR antagonist GS in DKD mice would reverse these beneficial effects by AAVASBT treatment. Conclusion: Our work indicated that restoring renal ASBT expression slowed the course of DKD via activating FXR. FXR activation stimulates mitochondrial biogenesis while reducing renal oxidative stress and lipid build up, indicating FXR activation's crucial role in preventing DKD. These findings further suggest that the maintenance of renal BA reabsorption could be a viable treatment for DKD. Summary at a glance: Restoring renal apical sodium‐dependent bile acid transporter (ASBT) expression attenuates diabetic kidney disease (DKD) progression through farnesoid X receptor activation, which promotes mitochondrial biogenesis and reduces oxidative stress and lipid accumulation.Modulating renal bile acid reabsorption via ASBT upregulation holds promise as a therapeutic approach for DKD management. [ABSTRACT FROM AUTHOR]

• Bile acid malabsorption (BAM) can generate functional chronic diarrhea. • Derangement of the gut-liver axis is involved in BAM. • BAM is frequently underdiagnosed but specific tests are available. • Therapies target enterohepatic BAs circulation by sequestrants and novel approaches. Bile acid malabsorption (BAM) is an important disorder of digestive pathophysiology as it generates chronic diarrhoea. This condition originates from intricate pathways involving bile acid synthesis and metabolism in the liver and gut, the composition of gut microbiota, enterohepatic circulation and key receptors as farnesoid X receptor (FXR), fibroblast growth factor receptor 4 (FGFR4), and the G-protein bile acid receptor-1 (GPBAR-1). Although symptoms can resemble those related to disorders of gut brain interaction, accurate diagnosis of BAM may greatly benefit the patient. The empiric diagnosis of BAM is primarily based on the clinical response to bile acid sequestrants. Specific tests including the 48-hour fecal bile acid test, serum levels of 7α-hydroxy-4-cholesten-3-one (C4) and fibroblast growth factor 19 (FGF19), and the 75Selenium HomotauroCholic Acid Test (SeHCAT) are not widely available. Nevertheless, lack of diagnostic standardization of BAM may account for poor recognition and delayed management. Beyond bile acid sequestrants, therapeutic approaches include the use of FXR agonists, FGF19 analogues, glucagon-like peptide-1 (GLP-1) receptor agonists, and microbiota modulation. These novel agents can best make their foray into the therapeutic armamentarium if BAM does not remain a diagnosis of exclusion. Ignoring BAM as a specific condition may continue to contribute to increased healthcare costs and reduced quality of life. Here, we aim to provide a comprehensive review of the pathophysiology, diagnosis, and management of BAM. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Bile acids are cholesterol-derived molecules that are primarily produced in the liver. In nonruminants with fatty liver, overproduction of bile acids is associated with liver injury. During the transition period, fatty liver is a metabolic disorder that can affect up to 50% of high-producing dairy cows. The purpose of this study was to provide a comprehensive evaluation of hepatic bile acid metabolism in dairy cows with fatty liver by assessing the expression changes of genes involved in bile acid synthesis, export, and uptake. The serum activities of aspartate aminotransferase, alanine aminotransferase, and glutamate dehydrogenase and the concentration of total bile acids were all greater, whereas the serum concentration of total cholesterol was lower in cows with fatty liver than in healthy cows. The content of total bile acids was higher, but total cholesterol was slightly lower in liver tissues from fatty liver cows than from healthy cows. The hepatic mRNA abundance of cholesterol 7a-hydroxylase (CYP7A1); hydroxy-delta-5-steroid dehydrogenase, 3 β- and steroid delta-isomerase 7 (HSD3B7); and sterol 12α-hydroxylase (CYP8B1), enzymes involved in the classic pathway of bile acid synthesis, was higher in fatty liver cows than in healthy cows. Compared with healthy cows, the hepatic mRNA abundance of alternative bile acid synthesis pathway-related genes sterol 27-hydroxylase (CYP27A1) and oxysterol 7α-hydroxylase (CYP7B1) did not differ in cows with fatty liver. The protein and mRNA abundances of bile acid transporter bile salt efflux pump (BSEP) were lower in the liver of dairy cow with fatty liver. Compared with healthy cows, the hepatic mRNA abundance of bile acid transporters solute carrier family 51 subunit α (SLC51A) and ATP binding cassette subfamily C member 1 (ABCC1) and 3 (ABCC3) was greater in cows with fatty liver, whereas the solute carrier family 51 subunit β (SLC51B) did not differ. The expression of genes involved in bile acid uptake, including solute carrier family 10 member 1 (NTCP), solute carrier organic anion transporter family member 1A2 (SLCO1A2) and 2B1 (SLCO2B1) was upregulated in dairy cows with fatty liver. Furthermore, the hepatic protein and mRNA abundance of bile acid metabolism regulators farnesoid X receptor (FXR) and small heterodimer partner (SHP) were lower in cows with fatty liver than in healthy cows. Overall, these data suggest that inhibition of the FXR signaling pathway may lead to increased bile acid synthesis and uptake and decreased secretion of bile acids from hepatocytes to the bile, which elevates hepatic bile acid content in dairy cows with fatty liver. Because the hepatotoxicity of bile acids has been demonstrated on nonruminant hepatocytes, it is likely that liver injury is induced by increased hepatic bile acid content in dairy cows with fatty liver. [ABSTRACT FROM AUTHOR]

Background and Purpose: Silibinin is used to treat non‐alcohol fatty liver disease (NAFLD) despite having rapid liver metabolism. Therefore, we investigated the role of the intestine in silibinin mechanism of action. Experimental Approach: NAFLD mice model was established by feeding them with a high‐fat diet (HFD). Liver pathological were examined using H&E and oil red O staining. Tissue distribution of silibinin was detected by LC–MS/MS. SiRNA was employed for gene silencing and plasmid was used for gene overexpression. ChIP‐qPCR assay was performed to detect the levels of histone acetylation. Recombinant adeno‐associated virus 9‐short hairpin‐fibroblast growth factor (FGF)‐15 and ‐farnesoid X receptor (FXR; NR1H4) were used to knockdown expression of FGF‐15 and FXR. Key Results: Oral silibinin significantly reversed NAFLD in mice, although liver concentration was insufficient for reduction of lipid accumulation in hepatocytes. Among endogenous factors capable of reversing NAFLD, the expression of Fgf‐15 was selectively up‐regulated by silibinin in ileum and colon of mice. When intestinal expression of Fgf‐15 was knocked down, protection of silibinin against lipid accumulation and injury of livers nearly disappeared. Silibinin could reduce activity of histone deacetylase 2 (HDAC2), enhance histone acetylation in the promoter region of FXR and consequently increase intestinal expression of FGF‐15/19. Conclusion and Implications: Oral silibinin selectively promotes expression of FGF‐15/19 in ileum by enhancing transcription of FXR via reduction of HDAC2 activity, and FGF‐15/19 enters into circulation to exert anti‐NAFLD action. As the site of action is the intestine this would explain the discrepancy between pharmacodynamics and pharmacokinetics of silibinin. [ABSTRACT FROM AUTHOR]

Background: Altered patterns of bile acids (BAs) are frequently present in liver fibrosis, and BAs function as signaling molecules to initiate inflammatory responses. Silybin meglumine (SLB-M) is widely used in treating various liver diseases including liver fibrosis. However, research on its effects on bile acid (BA) metabolism is limited. This study investigated the therapeutic effects of SLB-M on liver fibrosis and BA metabolism in a CCl4-induced murine model. Methods: A murine liver fibrosis model was induced by CCl4. Fibrosis was evaluated using HE, picrosirius red, and Masson's trichrome staining. Liver function was assessed by serum and hepatic biochemical markers. Bile acid (BA) metabolism was analyzed using LC-MS/MS. Bioinformatics analyses, including PPI network, GO, and KEGG pathway analyses, were employed to explore molecular mechanisms. Gene expression alterations in liver tissue were examined via qRT-PCR. Results: SLB-M treatment resulted in significant histological improvements in liver tissue, reducing collagen deposition and restoring liver architecture. Biochemically, SLB-M not only normalized serum liver enzyme levels (ALT, AST, TBA, and GGT) but also mitigated disruptions in both systemic and hepatic BA metabolism by increased unconjugated BAs like cholic acid and chenodeoxycholic acid but decreased conjugated BAs including taurocholic acid and taurodeoxycholic acid, compared to that in CCl4-induced murine model. Notably, SLB-M efficiently improved the imbalance of BA homeostasis in liver caused by CCl4 via activating Farnesoid X receptor. Conclusions: These findings underscore SLB-M decreased inflammatory response, reconstructed BA homeostasis possibly by regulating key pathways, and gene expressions in BA metabolism. [ABSTRACT FROM AUTHOR]

Every-other-day fasting (EODF) is a form of caloric restriction that alternates between periods of normal eating and fasting, aimed at preventing and treating diseases. This approach has gained widespread usage in basic research on neurological conditions, including spinal cord injury, and has demonstrated significant neuroprotective effects. Additionally, EODF is noted for its safety and feasibility, suggesting broad potential for application. This study aims to evaluate the therapeutic effects of EODF on spinal cord injury and to investigate and enhance its underlying mechanisms. Initially, the SCI rat model was utilized to evaluate the effects of EODF on pathological injury and motor function. Subsequently, considering the enhancement of metabolism through EODF, bile acid metabolism in SCI rats was analyzed using liquid chromatography-mass spectrometry (LC-MS), and the expression of the bile acid receptor TGR5 was further assessed. Ultimately, it was confirmed that EODF influences the activation of microglia and NLRP3 inflammasomes associated with the TGR5 signaling, along with the expression of downstream pyroptosis pathway related proteins and inflammatory cytokines, as evidenced by the activation of the NLRP3/Caspase-1/GSDMD pyroptosis pathway in SCI rats. The results demonstrated that EODF significantly enhanced the recovery of motor function and reduced pathological damage in SCI rats while controlling weight gain. Notably, EODF promoted the secretion of bile acid metabolites, activated TGR5, and inhibited the NLRP3/Caspase-1/GSDMD pyroptosis pathway and inflammation in these rats. In summary, EODF could mitigate secondary injury after SCI and foster functional recovery by improving metabolism, activating the TGR5 signaling and inhibiting the NLRP3 pyroptosis pathway. [ABSTRACT FROM AUTHOR]

The gut microbiota is widely regarded as a "metabolic organ" that could generate myriad metabolites to regulate human metabolism. As the microbiota metabolites, bile acids (BAs) have recently been identified as the critical endocrine molecules that mediate the cross-talk between the host and intestinal microbiota. This study provided a comprehensive insight into the gut microbiota and BA research through bibliometric analysis from 2003 to 2022. The publications on this subject showed a dramatic upward trend. Although the USA and China have produced the most publications, the USA plays a dominant role in this expanding field. Specifically, the University of Copenhagen was the most productive institution. Key research hotspots are the gut--liver axis, short-chain fatty acids (SCFAs), cardiovascular disease (CVD), colorectal cancer (CRC), and the farnesoid x receptor (FXR). The molecular mechanisms and potential applications of the gut microbiota and BAs in cardiometabolic disorders and gastrointestinal cancers have significant potential for further research. [ABSTRACT FROM AUTHOR]

Background: Fibroblast growth factor 19 (FGF19) is an enterohepatic hormone the synthesis of which is stimulated by bile acid activation of the nuclear farnesoid X receptor (FXR) in ileal enterocytes. Increased production of FGF19 downregulates hepatocyte bile acid synthesis and gluconeogenesis, while concurrently upregulating hepatocyte glycogenesis and gallbladder (GB) filling. The physiologic impact of this regulatory cycle is illustrated in cholecystectomized humans, in whom the disturbed meal‐related flux of GB bile decreases serum FGF19 concentrations. Objective: Determine if serum FGF19 concentrations are lower in dogs with clinical GB mucoceles (GBMs) than in control dogs. Animals: Seven dogs with GBM diagnosed using abdominal ultrasonography, biochemical markers, and GB histopathology. Forty‐two control dogs without gastrointestinal or hepatobiliary disorders also were evaluated. Health status of controls was assessed by physical examination and diagnostic hematologic and biochemical test results. Methods: Prospective cross‐sectional study to compare fasting plasma or serum FGF19 concentrations between groups. Concentrations of FGF19 were quantified by a commercially available FGF19 ELISA. Results: Concentrations of FGF19 were significantly lower in dogs with clinical GBM (median, 14.0 pg/mL; range, 12.8‐67.2) than in control dogs (median, 145.3 pg/mL; range, 36.5‐285.1). Conclusions and Clinical Importance: In dogs, GBM is associated with significantly decreased serum FGF19 concentrations. We speculate that this finding reflects compromised GB contraction and decreased enterohepatic circulation of bile flow. Subnormal FGF19 concentrations may influence bile acid synthesis and hepatic metabolism. [ABSTRACT FROM AUTHOR]

HIV disease remains prevalent in the United States and is particularly prevalent in sub-Saharan Africa. Recent investigations revealed that mitochondrial dysfunction in kidney contributes to HIV-associated nephropathy (HIVAN) in Tg26 transgenic mice. We hypothesized that nicotinamide adenine dinucleotide (NAD) deficiency contributes to energetic dysfunction and progressive tubular injury. We investigated metabolomic mechanisms of HIVAN tubulopathy. Tg26 and wild-type (WT) mice were treated with the farnesoid X receptor (FXR) agonist INT-747 or nicotinamide riboside (NR) from 6 to 12 wk of age. Multiomic approaches were used to characterize kidney tissue transcriptomes and metabolomes. Treatment with INT-747 or NR ameliorated kidney tubular injury, as shown by serum creatinine, the tubular injury marker urinary neutrophil-associated lipocalin, and tubular morphometry. Integrated analysis of metabolomic and transcriptomic measurements showed that NAD levels and production were globally downregulated in Tg26 mouse kidneys, especially nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in the NAD salvage pathway. Furthermore, NAD-dependent deacetylase sirtuin3 activity and mitochondrial oxidative phosphorylation activity were lower in ex vivo proximal tubules from Tg26 mouse kidneys compared with those of WT mice. Restoration of NAD levels in the kidney improved these abnormalities. These data suggest that NAD deficiency might be a treatable target for HIVAN. NEW & NOTEWORTHY: The study describes a novel investigation that identified nicotinamide adenine dinucleotide (NAD) deficiency in a widely used HIV-associated nephropathy (HIVAN) transgenic mouse model. We show that INT-747, a farnesoid X receptor agonist, and nicotinamide riboside (NR), a precursor of nicotinamide, each ameliorated HIVAN tubulopathy. Multiomic analysis of mouse kidneys revealed that NAD deficiency was an upstream metabolomic mechanism contributing to HIVAN tubulopathy. [ABSTRACT FROM AUTHOR]

Parenteral nutrition (PN) is a life-saving procedure conducted to maintain a proper nutritional state in patients with severe intestinal failure who cannot be fed orally. A serious complication of PN therapy is liver failure, known as intestinal failure-associated liver disease (IFALD). The pathogenesis of IFALD is multifactorial and includes inhibition of the farnesoid X receptor (FXR) by PN components, bacteria translocation from impaired intestines, and intravenous line-associated bloodstream infection. Currently, the most frequently researched therapeutic option for IFALD is using lipid emulsions based on soy or fish oil and, therefore, free from phytosterols known as FXR antagonists. Nevertheless, the potential side effects of the lack of soybean oil delivery seem to outweigh the benefits, especially in the pediatric population. PN admixture provides all the necessary nutrients; however, it is deprived of exogenous natural bioactive compounds (NBCs) of plant origin, such as polyphenols, characterized by health-promoting properties. Among them, many substances have already been known to demonstrate the hepatoprotective effect in various liver diseases. Therefore, searching for new therapeutic options for IFALD among NBCs seems reasonable and potentially successful. This review summarizes the recent research on polyphenols and their use in treating various liver diseases, especially metabolic dysfunction-associated steatotic liver diseases (MASLD). Furthermore, based on scientific reports, we have described the molecular mechanism of action of selected NBCs that exert hepatoprotective properties. We also summarized the current knowledge on IFALD pathogenesis, described therapeutic options undergoing clinical trials, and presented the future perspective of the potential use of NBCs in PN therapy. [Display omitted] • IFALD is a serious complication of PN therapy with a multifactorial pathogenesis. • Current treatment options involved mainly the reduction of phytosterols provision. • PN is deprived of natural bioactive compounds (NBCs). • Fourteen different NBCs were described, with varying properties in liver diseases. • NBCs showing hepatoprotective effects are promising agents for IFALD treatment. [ABSTRACT FROM AUTHOR]

The intricate relationship between bile acid (BA) metabolism, M2 macrophage polarization, and hepatitis B virus‐hepatocellular carcinoma (HBV‐HCC) necessitates a thorough investigation of ACSL4's (acyl‐CoA synthetase long‐chain family member 4) role. This study combines advanced bioinformatics and experimental methods to elucidate ACSL4's significance in HBV‐HCC development. Using bioinformatics, we identified differentially expressed genes in HBV‐HCC. STRING and gene set enrichment analysis analyses were employed to pinpoint critical genes and pathways. Immunoinfiltration analysis, along with in vitro and in vivo experiments, assessed M2 macrophage polarization and related factors. ACSL4 emerged as a pivotal gene influencing HBV‐HCC. In HBV‐HCC liver tissues, ACSL4 exhibited upregulation, along with increased levels of M2 macrophage markers and BA. Silencing ACSL4 led to heightened farnesoid X receptor (FXR) expression, reduced BA levels, and hindered M2 macrophage polarization, thereby improving HBV‐HCC conditions. This study underscores ACSL4's significant role in HBV‐HCC progression. ACSL4 modulates BA‐mediated M2 macrophage polarization and FXR expression, shedding light on potential therapeutic targets and novel insights into HBV‐HCC pathogenesis. [ABSTRACT FROM AUTHOR]

Bile acids serve as endogenous ligands for nuclear and cell membrane receptors and play a crucial role in bile acid and lipid metabolism. These detergent-like compounds promote bile flow and aid in the absorption of dietary fats and fat-soluble vitamins in the intestine. Synthesized in the liver as end products of cholesterol catabolism, bile acids exhibit a chemical structure comprising a nucleus and a side chain featuring a carboxyl group, with diverse steric arrangements and potential polar substituents. Critical interactions occur between bile acid species and various nuclear and cell membrane receptors, including the farnesoid X receptor and G-protein–coupled bile acid receptor 1. This research aimed to review the literature on bile acids and their roles in treating different diseases. Currently, numerous investigations are concentrating on specific bile acid species that target nuclear receptors in the gastrointestinal system, aiming to improve the treatment of conditions such as nonalcoholic fatty liver disease. Given the global attention this topic has garnered from research groups, it is considered relatively new, thus anticipating some gaps or incomplete data. Bile acid species have a significant therapeutic promise, especially in their ability to activate or inhibit nuclear receptors, such as farnesoid X receptor. This research provides to offer essential information for scientists and medical practitioners interested in discovering new studies that underscore the importance of bile acids in ameliorating and impeding the progression of disorders. Furthermore, it opens avenues for previously overlooked bile acid–based therapies.

Abstract Theabrownin (TB), which is derived from Pu‐erh tea and previously recognized as an intestinal farnesoid X receptor (FXR) antagonist, is known to have favorable effects on metabolic diseases such as hyperlipidemia and obesity. However, the mechanisms underlying the beneficial effects of TB in nonalcoholic fatty liver disease (NAFLD) require further exploration. This study aimed to use an NAFLD mouse model to evaluate changes in hepatic steatosis via the intestinal FXR–ceramide (Cer) axis following treatment with TB. The results indicated that TB alleviated hepatic steatosis and reduced total Cer levels in NAFLD mice. In particular, the levels of Cer(d18:1/16:0) in the intestine and liver were significantly reduced, which is considered to play a vital role in aggravating NAFLD. Furthermore, the transcriptional expression of Cer synthetase was markedly downregulated following treatment with TB or FXR antagonist, but this expression was reversed following treatment with a specific intestinal FXR agonist. These results indicate that TB alleviates NAFLD by reducing Cer levels via the inhibition of the intestinal FXR–Cer synthetase pathway.

Detect the expression of Farnesoid X Receptor(FXR), Multiple Drug Resistance Associated Protein-1(MRP-1) and Solute Carrier Family 7, Member 5 (SLC7A5) in hepatocellular carcinoma(HCC) of rat model, so as to provide new therapeutic targets for gene therapy of HCC. Sixty male Wistar rats were randomly divided into three groups. The rats in experimental group were given 0.2% diethylnitrosamine (DEN) by gavage with a dose of 10 mg/kg, 3 times a week, and it stopped at 12 weeks. The control group rats were given physiological saline by gavage, while the sham operation group did not receive anything by gavage. At 10 weeks, one rat in the experimental group was euthanized, and the changes of livers were recorded. The procedure was repeated at 12 weeks. After 12 weeks, HCC only occurred in the experimental group. After confirming the formation of the tumor through pathological examination, liver tissues and tumor tissues were taken from the three groups. FXR, MRP-1 and SLC7A5 expression in liver tissues and tumor tissues was detected. After 7 weeks the rats in experimental group ate less, and their weight was significantly reduced. Three months later, HCC was detected in 15 rats in the experimental group. The ratio of FXR/GAPDH mRNA, MRP-1/GAPDH mRNA, SLC7A5/GAPDH mRNA were significantly different among the three groups. Under the light microscope the FXR protein, MRP-1 protein, and SLC7A5 protein react with their respective antibodies, and they showed granular expression. Every pathological section included different numbers of positive cells in each group. FXR expression in HCC of rats was significantly lower than that in normal liver tissues, but MRP-1 and SLC7A5 expression in HCC were significantly higher than that in normal liver tissues, suggesting that drugs targeting FXR, MRP-1 and SLC7A5 may be new strategies for the treatment of HCC. [ABSTRACT FROM AUTHOR]

Platelets play a key role in physiological hemostasis and pathological thrombosis. Based on the limitations of current antiplatelet drugs, it's important to elucidate the mechanisms of regulating platelet activation. In addition to dissolving lipid nutrients, bile acids (BAs) can regulate platelet function. However, the specific mechanisms underlying BAs‐mediated effects on platelet activation and thrombotic diseases remain unknown. Therefore, the effects of BAs on platelets and intracellular regulatory mechanisms are explored. It is showed that the inhibitory effect of secondary BAs is more significant than that of primary BAs; lithocholic acid (LCA) shows the highest inhibitory effect. In the process of platelet activation, BAs suppress platelet activation via the spleen tyrosine kinase (SYK), protein kinase B (Akt), and extracellular signal‐regulated kinase1/2 (Erk1/2) pathways. Nck adaptor proteins (NCK1) deficiency significantly suppress the activity of platelets and arterial thrombosis. Phosphorylated proteomics reveal that LCA inhibited phosphorylation of syntaxin‐11 at S80/81 in platelets. Additional LCA supplementation attenuated atherosclerotic plaque development and reduced the inflammation in mice. In conclusion, BAs play key roles in platelet activation via Syk, Akt, ERK1/2, and syntaxin‐11 pathways, which are associated with NCK1. The anti‐platelet effects of BAs provide a theoretical basis for the prevention and therapy of thrombotic diseases. [ABSTRACT FROM AUTHOR]

A growing body of evidence indicates that the G protein-coupled bile acid receptor, TGR5, plays a critical role in multiple physiological processes ranging from metabolic disorders to cancers. However, the biological functions of TGR5 in cervical cancer (CC) have not been elucidated. Here, using TGR5 knockout mice, we found that a deficiency of TGR5 leads to greater sensitivity to the progression of cervical inflammation. Activation of TGR5 by its specific ligands significantly attenuated the malignant behavior of CC cells. In addition, we found that TGR5 can negatively modulate the expression of lncRNA HCP5 by blocking its transcription activation when mediated by p65. HCP5 was highly expressed in CC tissues, which was positively correlated with the poor prognosis of CC patients. HCP5 knockdown notably restrained CC cell proliferation, colony formation, and migration in vitro, and inhibited tumor growth in vivo. Furthermore, HCP5 can function as the molecular sponge for miR-139-5p to upregulate DNA damage-induced transcript 4 (DDIT4) in CC cells. Murine xenograft studies demonstrated that TGR5 suppressed the tumor formation of CC cells and downregulated HCP5 and DDIT4 while increasing miR-139-5p in the xenografts. Taken together, these findings, for the first time, indicate that TGR5 inhibits CC progression by regulating the HCP5/miR-139-5p/DDIT4 axis, suggesting that it may represent a novel and potent target for CC treatment. [ABSTRACT FROM AUTHOR]

5β-Dihydrosteroids are produced by the reduction of Δ4-3-ketosteroids catalyzed by steroid 5β-reductase (AKR1D1). By analogy with steroid 5α-reductase, genetic deficiency exists in AKR1D1 which leads to errors in newborn metabolism and in this case to bile acid deficiency. Also, like the 5α-dihydrosteroids (e.g., 5α-dihydrotestosterone), the 5β-dihydrosteroids produced by AKR1D1 are not inactive but regulate ligand access to nuclear receptors, can act as ligands for nuclear and membrane-bound receptors, and regulate ion-channel opening. For example, 5β-reduction of cortisol and cortisone yields the corresponding 5β-dihydroglucocorticoids which are inactive on the glucocorticoid receptor (GR) and provides an additional mechanism of pre-receptor regulation of ligands for the GR in liver cells. By contrast, 5β-pregnanes can act as neuroactive steroids at the GABAA and NMDA receptors and at low-voltage-activated calcium channels, act as tocolytic agents, have analgesic activity and act as ligands for PXR, while bile acids act as ligands for FXR and thereby control cholesterol homeostasis. The 5β-androstanes also have potent vasodilatory properties and work through blockade of Ca2+ channels. Thus, a preference for 5β-dihydrosteroids to work at the membrane level exists via a variety of mechanisms. This article reviews the field and identifies gaps in knowledge to be addressed in future research. [ABSTRACT FROM AUTHOR]

Intestinal failure‐associated liver disease (IFALD) is a serious complication of long‐term parenteral nutrition in patients with short bowel syndrome (SBS), and is the main cause of death in SBS patients. Prevention of IFALD is one of the major challenges in the treatment of SBS. Impairment of intestinal barrier function is a key factor in triggering IFALD, therefore promoting intestinal repair is particularly important. Intestinal repair mainly relies on the function of intestinal stem cells (ISC), which require robust mitochondrial fatty acid oxidation (FAO) for self‐renewal. Herein, we report that aberrant LGR5+ ISC function in IFALD may be attributed to impaired farnesoid X receptor (FXR) signaling, a transcriptional factor activated by steroids and bile acids. In both surgical biopsies and patient‐derived organoids (PDOs), SBS patients with IFALD represented lower population of LGR5+ cells and decreased FXR expression. Moreover, treatment with T‐βMCA in PDOs (an antagonist for FXR) dose‐dependently reduced the population of LGR5+ cells and the proliferation rate of enterocytes, concomitant with decreased key genes involved in FAO including CPT1a. Interestingly, however, treatment with Tropifexor in PDOs (an agonist for FXR) only enhanced FAO capacity, without improvement in ISC function and enterocyte proliferation. In conclusion, these findings suggested that impaired FXR may accelerate the depletion of LGR5 + ISC population through disrupted FAO processes, which may serve as a new potential target of preventive interventions against IFALD for SBS patients. [ABSTRACT FROM AUTHOR]

The farnesoid X receptor (FXR), a ligand-activated transcription factor, plays a crucial role in regulating bile acid metabolism within the enterohepatic circulation. Beyond its involvement in metabolic disorders and immune imbalances affecting various tissues, FXR is implicated in microbiota modulation, gut-to-brain communication, and liver disease. The liver, as a pivotal metabolic and detoxification organ, is susceptible to damage from factors such as alcohol, viruses, drugs, and high-fat diets. Chronic or recurrent liver injury can culminate in liver fibrosis, which, if left untreated, may progress to cirrhosis and even liver cancer, posing significant health risks. However, therapeutic options for liver fibrosis remain limited in terms of FDA-approved drugs. Recent insights into the structure of FXR, coupled with animal and clinical investigations, have shed light on its potential pharmacological role in hepatic fibrosis. Progress has been achieved in both fundamental research and clinical applications. This review critically examines recent advancements in FXR research, highlighting challenges and potential mechanisms underlying its role in liver fibrosis treatment. [ABSTRACT FROM AUTHOR]

Accumulating literature suggests that the farnesoid-X receptor (FXR), a nuclear bile acid receptor best known for its role in bile acid homeostasis, is also a potent context-dependent regulator of inflammation. FXR may thus be relevant to several intestinal disease states including inflammatory bowel disease, necrotizing enterocolitis, and sepsis. In this study, we tested the effects of FXR deletion on acute murine intestinal inflammation. We found that FXR knockout (KO) mice were protected from intestinal injury and barrier dysfunction induced by lipopolysaccharide (LPS) injection, dithizone (DI)/Klebsiella, and cecal ligation/puncture models. In the LPS model, RNA sequencing and qPCR analysis showed that this protection correlated with substantial reduction in LPSinduced proinflammatory gene expression, including lower tissue levels of Il1a, Il1b, and Tnf. Examining functional effects on the epithelium, we found that LPS-induced tight junctional disruption as assessed by internalization of ZO-1 and occludin was ameliorated in FXR KO animals. Taken together, these data suggest a role for FXR in the intestinal barrier during inflammatory injury. NEW & NOTEWORTHY Intestinal barrier failure is a hallmark in gut-origin sepsis. We demonstrate that the intestinal barriers of farnesoid-X receptor (FXR) knockout (KO) animals are protected from inflammatory insult using multiple models of acute intestinal inflammation. This protection is due to decreased inflammatory cytokine production and maintenance of tight junctional architecture seen within the KO animals. This is the first report of FXR deletion being protective to the intestinal barrier. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Besides their lipid-digestive role, bile acids (BA) influence overall energy homeostasis, such as glucose and lipid metabolism. We hypothesized that BA along with their receptors, regulatory enzymes, and transporters are present in subcutaneous adipose tissue (scAT). In addition, we hypothesized that their mRNA abundance varies with the body condition of dairy cows around calving. Therefore, we analyzed BA in serum and scAT as well as the mRNA abundance of BA-related enzymes, transporters, and receptors in scAT during the transition period in cows with different body conditions around calving. In a previously established animal model, 38 German Holstein cows were divided into either a high (HBCS; n = 19) or normal BCS (NBCS; n = 19) group based on their BCS and back-fat thickness (BFT). Cows were fed different diets to achieve the targeted differences in BCS and BFT (NBCS: BCS <3.5, BFT <1.2 cm; HBCS: BCS >3.75, BFT >1.4 cm) until dry-off at 7 wk antepartum. During the dry period and subsequent lactation, both groups were fed the same diets according to their energy demands. Using a targeted metabolomics approach via liquid chromatography-electrospray ionization-MS /MS, BA were analyzed in serum and scAT at wk −7, 1, 3, and 12 relative to parturition. In serum, 15 BA were observed: cholic acid (CA), chenodeoxycholic acid (CDCA), glycocholic acid (GCA), taurocholic acid (TCA), glycochenodeoxycholic acid (GCDCA), taurochenodeoxycholic acid, deoxycholic acid (DCA), lithocholic acid, glycodeoxycholic acid (GDCA), glycolithocholic acid, taurodeoxycholic acid, taurolithocholic acid, β-muricholic acid, tauromuricholic acid (sum of α and β), and glycoursodeoxycholic acid, whereas in scAT 7 BA were detected: CA, GCA, TCA, GCDCA, taurochenodeoxycholic acid, GDCA, and taurodeoxycholic acid. In serum and scAT samples, the primary BA CA and its conjugate GCA were predominantly detected. Increasing serum concentrations of CA, CDCA, TCA, GCA, GCDCA, DCA, and β-muricholic acid with the onset of lactation might be related to the increasing DMI after parturition. Furthermore, serum concentrations of CA, CDCA, GCA, DCA, GCDCA, TCA, lithocholic acid, and GDCA were lower in HBCS cows compared with NBCS cows, concomitant with increased lipolysis in HBCS cows. The correlation between CA in serum and scAT may point to the transport of CA across cell membranes. Overall, the findings of the present study suggest a potential role of BA in lipid metabolism depending on the body condition of periparturient dairy cows. [ABSTRACT FROM AUTHOR]

Hepatitis B virus (HBV) is a hepatotropic non‐cytopathic virus characterized by liver‐specific gene expression. HBV infection highjacks bile acid metabolism, notably impairing bile acid uptake via sodium taurocholate cotransporting polypeptide (NTCP), which is a functional receptor for HBV entry. Concurrently, HBV infection induces changes in bile acid synthesis and the size of the bile acid pool. Conversely, bile acid facilitates HBV replication and expression through the signaling molecule farnesoid X receptor (FXR), a nuclear receptor activated by bile acid. However, in HepaRG cells and primary hepatocytes, FXR agonists suppress HBV RNA expression and the synthesis and secretion of DNA. In the gut, the size and composition of the bile acid pool significantly influence the gut microbiota. In turn, the gut microbiota impacts bile acid metabolism and innate immunity, potentially promoting HBV clearance. Thus, the bile acid–gut microbiota axis represents a complex and evolving relationship in the context of HBV infection. This review explores the interplay between bile acid and gut microbiota in HBV infection and discusses the development of HBV entry inhibitors targeting NTCP. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Microbial metabolite trimethylamine-N-oxide induces intestinal carcinogenesis through inhibiting farnesoid X receptor signaling" published in Cellular Oncology. The correction addresses errors in the abstract and figures of the original article. Specifically, the correction clarifies that the changes induced by trimethylamine-N-oxide (TMAO) in the intestinal microbial community structure resulted in reduced beneficial bacteria, not reduced microbiota diversity. Additionally, there were errors in the representative pictures and data in Figure 2e and 2g, which have been corrected. The correction also includes revisions to the description of the Firmicutes/Bacteroidetes (F/B) ratio and the number of unique operational taxonomic units (OTUs) detected in the study. The original article has been corrected. [Extracted from the article]

Purpose: Microbial dysbiosis is considered as a hallmark of colorectal cancer (CRC). Trimethylamine-N-oxide (TMAO) as a gut microbiota-dependent metabolite has recently been implicated in CRC development. Nevertheless, evidence relating TMAO to intestinal carcinogenesis remains largely unexplored. Herein, we aimed to examine the crucial role of TMAO in CRC progression. Methods: Apcmin/+ mice were treated with TMAO or sterile PBS for 14 weeks. Intestinal tissues were isolated to evaluate the effects of TMAO on the malignant transformation of intestinal adenoma. The gut microbiota of mouse feces was detected by 16S rRNA sequencing analysis. HCT-116 cells were used to provide further evidence of TMAO on the progression of CRC. Results: TMAO administration increased tumor cell and stem cell proliferation, and decreased apoptosis, accompanied by DNA damage and gut barrier impairment. Gut microbiota analysis revealed that TMAO induced changes in the intestinal microbial community structure, manifested as reduced beneficial bacteria. Mechanistically, TMAO bound to farnesoid X receptor (FXR), thereby inhibiting the FXR-fibroblast growth factor 15 (FGF15) axis and activating the Wnt/β-catenin signaling pathway, whereas the FXR agonist GW4064 could blunt TMAO-induced Wnt/β-catenin pathway activation. Conclusion: The microbial metabolite TMAO can enhance intestinal carcinogenesis by inhibiting the FXR-FGF15 pathway. [ABSTRACT FROM AUTHOR]

With advances in next-generation sequencing technology, there is growing evidence that the gut microbiome plays a key role in the host's innate and adaptive immune system. Gut microbes and their metabolites directly or indirectly regulate host immune cells. Crucially, dysregulation of the gut microbiota is often associated with many immune system diseases. In turn, microbes modulate disease immunotherapy. Data from preclinical to clinical studies suggest that the gut microbiota may influence the effectiveness of tumor immunotherapy, particularly immune checkpoint inhibitors (ICIs). In addition, the most critical issue now is a COVID-19 vaccine that generates strong and durable immunity. A growing number of clinical studies confirm the potential of gut microbes to enhance the efficacy of COVID-19 vaccines. However, it is still unclear how gut bacteria interact with immune cells and what treatments are based on gut microbes. Here, we outline recent advances in the effects and mechanisms of the gut microbiota and its metabolites (tryptophan metabolites, bile acids, short-chain fatty acids, and inosine) on different immune cells (dendritic cells, CD4+T cells, and macrophages). It also highlights innovative intervention strategies and clinical trials of microbiota-based checkpoint blocking therapies for tumor immunity, and ongoing efforts to maintain the long-term immunogenicity of COVID-19 vaccines. Finally, the challenges to be overcome in this area are discussed. These provide an important basis for further research and clinical translation of gut microbiota. [ABSTRACT FROM AUTHOR]

Consumption of herbal products containing pyrrolizidine alkaloids (PAs) is one of the major causes for hepatic sinusoidal obstruction syndrome (HSOS), a deadly liver disease. However, the crucial metabolic variation and biomarkers which can reflect these changes remain amphibious and thus to result in a lack of effective prevention, diagnosis and treatments against this disease. The aim of the study was to determine the impact of HSOS caused by PA exposure, and to translate metabolomics-derived biomarkers to the mechanism. In present study, cholic acid species (namely, cholic acid, taurine conjugated-cholic acid, and glycine conjugated-cholic acid) were identified as the candidate biomarkers (area under the ROC curve 0.968 [95% CI 0.908–0.994], sensitivity 83.87%, specificity 96.55%) for PA-HSOS using two independent cohorts of patients with PA-HSOS. The increased primary bile acid biosynthesis and decreased liver expression of farnesoid X receptor (FXR, which is known to inhibit bile acid biosynthesis in hepatocytes) were highlighted in PA-HSOS patients. Furtherly, a murine PA-HSOS model induced by senecionine (50 mg/kg, p.o.), a hepatotoxic PA, showed increased biosynthesis of cholic acid species via inhibition of hepatic FXR-SHP singling and treatment with the FXR agonist obeticholic acid restored the cholic acid species to the normal levels and protected mice from senecionine-induced HSOS. This work elucidates that increased levels of cholic acid species can serve as diagnostic biomarkers in PA-HSOS and targeting FXR may represent a therapeutic strategy for treating PA-HSOS in clinics. [ABSTRACT FROM AUTHOR]

Cholestatic liver diseases, including primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC), result from an impairment of bile flow that leads to the hepatic retention of bile acids, causing liver injury. Until recently, the only approved treatments for PBC were ursodeoxycholic acid (UDCA) and obeticholic acid (OCA). While these therapies slow the progression of PBC in the early stage of the disease, approximately 40% of patients respond incompletely to UDCA, and advanced cases do not respond. UDCA does not improve survival in patients with PSC, and patients often have dose-limiting pruritus reactions to OCA. Left untreated, these diseases can progress to fibrosis and cirrhosis, resulting in liver failure and the need for transplantation. These shortcomings emphasize the urgent need for alternative treatment strategies. Recently, nuclear hormone receptors have been explored as pharmacological targets for adjunct therapy because they regulate enzymes involved in bile acid metabolism and detoxification. In particular, the peroxisome proliferator-activated receptor (PPAR) has emerged as a therapeutic target for patients with PBC or PSC who experience an incomplete response to UDCA. PPARα is predominantly expressed in the liver, and it plays an essential role in the regulation of cytochrome P450 (CYP) and uridine 5'-diphospho-glucuronosyltransferase (UGT) enzymes, both of which are critical enzyme families involved in the regulation of bile acid metabolism and glucuronidation, respectively. Importantly, PPARα agonists, e.g., fenofibrate, have shown therapeutic benefits in reducing elevated markers of cholestasis in patients with PBC and PSC, and elafibranor, the first PPAR (dual α, β/δ) agonist, has been FDA-approved for the second-line treatment of PBC. Additionally, newer PPAR agonists that target various PPAR isoforms (β/δ, γ) are under development as an adjunct therapy for PBC or PSC, although their impact on glucuronidation pathways are less characterized. This review will focus on PPAR-mediated bile acid glucuronidation as a therapeutic pathway to improve outcomes for patients with PBC and PSC. [ABSTRACT FROM AUTHOR]

Human pregnane X receptor (PXR) is critical for regulating the expression of key drug‐metabolizing enzymes such as CYP3A and CYP2C. Our recent study revealed that treatment with rodent‐specific PXR agonist pregnenolone‐16α‐carbonitrile (PCN) significantly induced hepatomegaly and promoted liver regeneration after two‐thirds partial hepatectomy (PHx) in mice. However, it remains unclear whether PXR activation induces hepatomegaly and liver regeneration and simultaneously promotes metabolic function of the liver. Here, we investigated the metabolism activity of CYP1A2, CYP3A1/2 and CYP2C6/11 during PXR activation‐induced liver enlargement and regeneration in rats after cocktail dosing of CYP probe drugs. For PCN‐induced hepatomegaly, a notable increase in the metabolic activity of CYP3A1/2 and CYP2C6/11, as evidenced by the plasma exposure of probe substrates and the AUC ratios of the characteristic metabolites to its corresponding probe substrates. The metabolic activity of CYP1A2, CYP3A1/2 and CYP2C6/11 decreased significantly after PHx. However, PCN treatment obviously enhanced the metabolic activity of CYP2C6/11 and CYP3A1/2 in PHx rats. Furthermore, the protein expression levels of CYP3A1/2 and CYP2C6/11 in liver were up‐regulated. Taken together, this study demonstrates that PXR activation not only induces hepatomegaly and liver regeneration in rats, but also promotes the protein expression and metabolic activity of the PXR downstream metabolizing enzymes such as CYP3A1/2 and CYP2C6/11 in the body. [ABSTRACT FROM AUTHOR]

Bile acids (BAs) are natural metabolites in mammals and have the potential to function as drugs against viral infection. However, the limited understanding of chenodeoxycholic acid (CDCA) receptors and downstream signaling, along with its lower suppression efficiency in inhibiting virus infection limits its clinical application. In this study, we demonstrate that farnesoid X receptor (FXR), the receptor of CDCA, negatively regulates interferon signaling, thereby contributing to the reduced effectiveness of CDCA against virus replication. FXR deficiency or pharmacological inhibition enhances interferon signaling activation to suppress virus infection. Mechanistically, FXR impairs the DNA binding and transcriptional abilities of activated interferon regulatory factor 3 (IRF3) through interaction. Reduced IRF3 transcriptional activity by FXR–IRF3 interaction significantly undermines the expression of Interferon Beta 1 (IFNB1) and the antiviral response of cells, especially upon the CDCA treatment. In FXR -deficient cells, or when combined with Z -guggulsterone (GUGG) treatment, CDCA exhibits a more potent ability to restrict virus infection. Thus, these findings suggest that FXR serves as a limiting factor for CDCA in inhibiting virus replication, which can be attributed to the "signaling-brake" roles of FXR in interferon signaling. Targeting FXR inhibition represents a promising pharmaceutical strategy for the clinical application of BAs metabolites as antiviral drugs. FXR inhibition enhances antiviral potency of chenodeoxycholic acid by relieving FXR interference with interferon signaling, indicating FXR as a promising target for augmenting bile acids' antiviral effects. [Display omitted] [ABSTRACT FROM AUTHOR]

Environmental pollution, virus infection, allergens, and other factors may cause respiratory disease, which could be improved by dietary therapy. Allium species are common daily food seasoning and have high nutritional and medical value. Diallyl disulfide (DADS) is the major volatile oil compound of Allium species. The present study aims to explore the preventive effect and potential mechanism of DADS on pulmonary fibrosis. C57BL/6J mice were intratracheally injected with bleomycin (BLM) to establish pulmonary fibrosis and then administrated with DADS. Primary lung fibroblasts or A549 were stimulated with BLM, followed by DADS, farnesoid X receptor (FXR) agonist (GW4064), yes‐associated protein 1 (YAP1) inhibitor (verteporfin), or silencing of FXR and YAP1. In BLM‐stimulated mice, DADS significantly ameliorated histopathological changes and interleukin‐1β levels in bronchoalveolar lavage fluid. DADS decreased fibrosis markers, HIF‐1α, inflammatory cytokines, and epithelial‐mesenchymal transition in pulmonary mice and activated fibroblasts. DADS significantly enhanced FXR expression and inhibited YAP1 activation, which functions as GW4064 and verteporfin. A deficiency of FXR or YAP1 could result in the increase of these two protein expressions, respectively. DADS ameliorated extracellular matrix deposition, hypoxia, epithelial‐mesenchymal transition, and inflammation in FXR or YAP1 knockdown A549. Taken together, targeting the crosstalk of FXR and YAP1 might be the potential mechanism for DADS against pulmonary fibrosis. DADS can serve as a potential candidate or dietary nutraceutical supplement for the treatment of pulmonary fibrosis. [ABSTRACT FROM AUTHOR]

Fufang Muji granules (FMGs) are a prominent modern prescription Chinese patent formulation derived from the Muji decoction. Utilized in clinical practice for nearly four decades, FMGs have demonstrated efficacy in treating liver diseases. However, the precise mechanism of action remains unclear. This study investigates the hepatoprotective effects of FMGs against liver fibrosis in rats based on untargeted metabolomics and elucidates their underlying mechanisms. A comprehensive model of liver fibrosis was established with 30% CCl4 (2 mL/kg) injected intraperitoneally, and a fat and sugar diet combined with high temperatures and humidity. Rats were orally administered FMGs (3.12 g/kg/d) once daily for six weeks. FMG administration resulted in improved liver fibrosis and attenuated hepatic oxidative stress and apoptosis. Furthermore, FMGs inhibited hepatic stellate cell activation and modulated transforming growth factor β1/Smad signaling. Additionally, FMG treatment influenced the expression levels of interleukin-6, interleukin-1β, and tumour necrosis factor alpha in the injured liver. Metabolic pathways involving taurine and hypotaurine metabolism, as well as primary bile acid biosynthesis, were identified as mechanisms of action for FMGs. Immunohistochemistry, quantitative reverse transcription polymerase chain reaction (RT-qPCR), and quantitative analysis also revealed that FMGs regulated taurine and hypotaurine metabolism and bile acid metabolism. These findings provide a valuable understanding of the role of FMGs in liver fibrosis management. [ABSTRACT FROM AUTHOR]

BAR502, a bile acid analogue, is active as dual FXR/GPBAR1 agonist and represents a promising lead for the treatment of cholestasis and NASH. In this paper we report the synthesis and the biological evaluation of a library of hybrid compounds prepared by combining, through high-yield condensation reaction, some fibrates with BAR502.The activity of the new conjugates was evaluated towards FXR, GPBAR1 and PPARa receptors, employing transactivation or cofactor recruitment assays. Compound 1 resulted as the most promising of the series and was subjected to further pharmacological investigation, together with stability evaluation and cell permeation assessment. We have proved by LCMS analysis that compound 1 is hydrolyzed in mice releasing clofibric acid and BAR505, the oxidized metabolite of BAR502, endowed with retained dual FXR/ GPBAR1 activity. [ABSTRACT FROM AUTHOR]

Primary biliary cholangitis (PBC) is a chronic autoimmune cholestatic disease characterized by the destruction of the small intrahepatic bile ducts, which can progress to liver cirrhosis. The gold standard in the treatment of PBC is ursodeoxycholic acid (UDCA), which is indicated in all patients with PBC because it improves not only biochemical parameters but also patients' survival. An important milestone in the identification of patients at risk is the assessment of biochemical response to UDCA. Patients who respond to treatment have a lower incidence of hepatic events and better prognosis than patients who do not. Several scoring systems can be used to assess the response and identify non-responders who will benefit from second-line treatment. Obeticholic acid (OCA) is currently the only approved second-line treatment for PBC, which is effective for non-responders to UDCA therapy or patients, who have not tolerated UDCA therapy. However, OCA is contraindicated in advanced liver cirrhosis and portal hypertension. Moreover, pruritus may be a limiting factor for the administration of OCA. Fibrates have shown promising data supporting their use in non-responders to UDCA because they improve the biochemical parameters and elastographic findings and have possible antipruritic effects. Therefore, the idea of a triple treatment seems interesting. Clinical research is focusing on several other groups of drugs: peroxisome proliferator-activated receptor (PPAR) δ- and α/δ agonists, non-steroidal farnesoid X receptor agonists, fibroblast growth factor 19 modulators, and inhibitors of nicotinamide adenine dinucleotide phosphate oxidase 1 and 4. [ABSTRACT FROM AUTHOR]

This study investigates sex-specific effects in a gain-of-function model to evaluate Nfil3 function in relation to high-fat diet (HFD)-induced metabolic dysfunction-associated steatotic liver disease (MASLD) and gut microbiota (GM)-induced alterations in the bile acid (BA) profile. MASLD is induced in both wild type and Nfil3-deficient (NKO) C57BL/6 J mice through an HFD. The hepatic immune response is evaluated using flow cytometry, revealing that NKO mice exhibit lower body weight, serum triglyceride (TG) levels, tissue injury, inflammation, and fat accumulation. The Nfil3 deletion reduces macrophage counts in fibrotic liver tissues, decreases proinflammatory gene and protein expression, and diminishes gut barrier function. Alpha and beta diversity analysis reveal increased GM alpha diversity across different sexes. The Nfil3 gene deletion modifies the BA profile, suggesting that negative feedback through the Nfil3-FXR-FGF15 axis facilitates BA recycling from the liver via enterohepatic circulation. Therefore, inhibiting Nfil3 in the liver offers a viable treatment approach for MASLD. This study explores the role of nuclear factor interleukin 3 (Nfil3) in metabolic dysfunction-associated fatty liver disease (MASLD) development, revealing sex-specific effects and gut microbiota influence on bile acid metabolism. [ABSTRACT FROM AUTHOR]

Gut microbiota can influence host gene expression and physiology through metabolites. Besides, the presence or absence of gut microbiome can reprogram host transcriptome and epitranscriptome as represented by N6‐methyladenosine (m6A), the most abundant mammalian mRNA modification. However, which and how gut microbiota‐derived metabolites reprogram host transcriptome and m6A epitranscriptome remain poorly understood. Here, investigation is conducted into how gut microbiota‐derived metabolites impact host transcriptome and m6A epitranscriptome using multiple mouse models and multi‐omics approaches. Various antibiotics‐induced dysbiotic mice are established, followed by fecal microbiota transplantation (FMT) into germ‐free mice, and the results show that bile acid metabolism is significantly altered along with the abundance change in bile acid‐producing microbiota. Unbalanced gut microbiota and bile acids drastically change the host transcriptome and the m6A epitranscriptome in multiple tissues. Mechanistically, the expression of m6A writer proteins is regulated in animals treated with antibiotics and in cultured cells treated with bile acids, indicating a direct link between bile acid metabolism and m6A biology. Collectively, these results demonstrate that antibiotic‐induced gut dysbiosis regulates the landscape of host transcriptome and m6A epitranscriptome via bile acid metabolism pathway. This work provides novel insights into the interplay between microbial metabolites and host gene expression. [ABSTRACT FROM AUTHOR]

Emodin (EMO) has the effect of anti-cholestasis induced by alpha-naphthylisothiocyanate (ANIT). But its mechanism is still unclear. The farnesoid X receptor (Fxr) is the master bile acid nuclear receptor. Recent studies have reported that Sirtuin 1 (Sirt1) can regulate the activities of Fxr. The purpose of the current study was to investigate the mechanism of EMO against ANIT-induced liver injury based on Sirt1/Fxr signaling pathway. The ANIT-induced cholestatic rats were used with or without EMO treatment. Serum biochemical indicators, as well as liver histopathological changes were examined. The genes expressions of Sirt1, Fxr, Shp, Bsep and Mrp2 were detected. The expressions of Sirt1, Fxr and their downstream related genes were investigated in vitro. The results showed that EMO significantly alleviated ANIT-induced liver injury in rats, and increased Sirt1, Fxr, Shp, Bsep and Mrp2 gene expression in liver, while decreased the expression of Cyp7a1. EMO significantly activated Fxr, while Sirt1 inhibitor and Sirt1 gene silencing significantly reduced Fxr activity in vitro. Collectively, EMO in the right dose has a protective effect on liver injury induced by ANIT, and the mechanism may be through activation of Fxr by Sirt1, thus regulating bile acid metabolism, and reducing bile acid load in hepatocytes. [ABSTRACT FROM AUTHOR]