Search Results (169)

Background: Oxidative liver damage, fibrosis, cirrhosis and liver failure are caused by reactive oxygen species and inflammatory responses triggered by bile retention during prolonged cholestasis. Pomegranate and persimmon fruits, which are loaded with bioactive compounds that have anti-inflammatory and antioxidant properties, were evaluated separately for their efficacy in preventing oxidative stress and inflammation in cholestasis. Methods: Pomegranate and persimmon juices were analyzed for their vitamin C, carotenoids and organic acid levels, phenolic profile, and antioxidant activity. Liver protection against oxidative stress and inflammation brought on by cyclosporine-induced cholestasis in rats was verified by biochemical measurements, metabolite identification, and histopathologic examination. To forecast the mechanism of pomegranate and persimmon anti-inflammatory action, an in silico assessment was also carried out. Results: Vitamin C levels in pomegranate and persimmon juices were 99.55 and 51.75 µg/g, respectively. In both pomegranate and persimmon juices, gallic acid was the most prevalent phenolic compound (123.20 and 50.69 µg/g, respectively). Pomegranate and persimmon juices significantly (p < 0.05) reduced the rise in liver values of MDA, NO, TNF-α, IL-6, IL-1β, and TLR4, as well as serum values of total and direct bilirubin caused by cyclosporine. Additionally, the alteration of metabolites, particularly amino acids, demonstrated the inhibitory effect of pomegranate and persimmon juices on liver damage. Gallic acid’s and catechin’s substantial binding affinities with target inflammatory cytokines (TNF-α and TLR4) were further validated by molecular docking. Conclusions: These results showed that pomegranate and persimmon juices mainly modulated inflammation and oxidative stress to provide hepato-protective benefits against cyclosporine-induced cholestatic liver injury. Full article

Nutrient-sensing nuclear receptors (NSNRs), including PPARs, FXR, LXRs, RAR/RXR, VDR, and related orphan receptors, integrate a molecular interface that allows diet to communicate directly with the genome. By binding fatty acids, bile acids, sterols, vitamins, polyphenols, and other food-derived metabolites, NSNRs translate qualitative and quantitative features of the diet into coordinated transcriptional programmes across metabolically active organs. This ligand-dependent signalling network integrates dietary information to orchestrate inter-organ lipid and glucose metabolism, mitochondrial function, thermogenesis, and immune response, thereby enabling the organism to adapt dynamically to fasting–feeding cycles. In this review, we synthesise current evidence on the integrated roles of major NSNRs in the liver, skeletal muscle, white and brown adipose tissue, and kidney, emphasising how receptor networks within and between metabolic organs collectively govern energy expenditure, substrate partitioning, and systemic metabolic flexibility. We propose a conceptual framework in which diet functions as an “external endocrine organ”, acting as the primary source of chemically diverse NSNR ligands, while metabolic tissues serve as secondary signal amplifiers and integrators. Through circulating lipid species, bile acids, oxysterols, and other metabolites, these organs engage in continuous bidirectional communication that reprograms NSNR activity across tissues. We then examine how the global shift from minimally processed, nutrient-rich foods to nutrient-poor, energy-dense ultra-processed diets leads to a reduction in NSNR ligand diversity, promoting hepatic steatosis, muscle metabolic inflexibility, adipose tissue dysfunction, renal lipotoxicity, and chronic low-grade inflammation, ultimately causing obesity, type 2 diabetes, and cardiometabolic disease. Finally, we explore strategies to restore NSNR function, including Mediterranean and plant-based dietary patterns, as well as diets enriched with ω-3 polyunsaturated fatty acids, monounsaturated fats, and polyphenols. By integrating molecular, physiological, and clinical evidence, this review aims to clarify how NSNR networks translate dietary cues into coordinated inter-organ metabolism and how nutrient-poor diets lead to metabolic diseases trough a loss of metabolic information, rather than merely by energy excess. This framework supports a paradigm shift from calorie-centred nutrition to diet quality as the main therapeutic target for preventing metabolic diseases and promoting health. Full article

The presence of an unbalanced gut microbiome and the dysregulation of bile acid signalling are considered pivotal causes of various inflammation-based diseases. The Takeda G protein-coupled receptor (TGR5), TGR5 is a bile acid-responsive receptor that modulates inflammatory signalling pathways, making it an enticing molecular target for the discovery of novel anti-inflammatory agents. Herein, a comprehensive in silico approach was employed to identify potential TGR5 agonists from sterol-rich phytocompounds present in Triphala, a traditional polyherbal formulation. Using in silico computational methods, such as molecular docking and molecular dynamics simulations (MDS), we screened the putative agonistic potential of 10 phytocompounds obtained from Terminalia chebula, Terminalia bellirica, and Phyllanthus emblica against the crystal structure of human TGR5 (PDB ID: 7XTQ). Based on binding energy and molecular interactions, ergosterol (−12.34 ± 0.17 kcal/mol) and stigmasterol (−10.35 ± 0.04 kcal/mol) were predicted to be the top and best compounds. Furthermore, the stability of these two compounds in the docked complex was analysed using MDS for 200 ns. The mean Cα RMSD values were 0.22 ± 0.02 nm for both ergosterol- and stigmasterol-bound complexes, compared to 0.21 ± 0.02 nm for the unbound apo protein. Further, the molecular mechanics/Poisson–Boltzmann surface area (MMPBSA) analysis revealed that ergosterol exhibited binding free energy (−139.868 ± 12.318 kJ/mol) comparable to that of the co-crystallised ligand R399 −93.424 ± 8.919 kJ/mol. In silico ADMET predictions indicated acceptable drug-like properties and low toxicity for both compounds. Collectively, these computational findings suggest that ergosterol is a promising putative TGR5 agonist, warranting further experimental validation of its potential role in modulating inflammation-related pathways. Full article

This study aimed to systematically elucidate the antihyperlipidemic mechanism of paeoniflorin, and we adopted an integrated multi-omics strategy to screen the key molecular targets and regulatory pathways involved in its action, followed by experimental validation to verify the potential regulatory effects of paeoniflorin on the screened targets and metabolic processes. Rats with high-fat diet-induced hyperlipidemia received paeoniflorin treatment. Liver histopathology was evaluated using hematoxylin–eosin and Oil Red O staining. Serum levels of total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bile acids, activated partial thromboplastin time, prothrombin time, thrombin time, and fibrinogen were measured using a biochemical analyzer. Integrated multi-omics analyses were performed to investigate paeoniflorin’s lipid-lowering mechanism. Critical pathways and targets identified were validated using Western blotting. Paeoniflorin alleviated pathological liver damage in hyperlipidemic rats and improved blood lipid levels, coagulation function, and liver function markers. Multi-omics analyses verified that paeoniflorin downregulated the expression of TREM-1, TLR4, NF-κB, TNF-α, and IL-1β, thereby alleviating hepatic inflammation. Paeoniflorin also upregulated the expression of low-density lipoprotein receptors (LDLR), liver X receptor alpha (LXRα), and ATP-binding cassette subfamily G member 1 (ABCG1), while downregulating proprotein convertase subtilisin/kexin type 9 (PCSK9) expression, contributing to balanced cholesterol metabolism. Paeoniflorin normalized glycerophospholipid and branched-chain amino acid metabolism, which correlated with reduced inflammation and improved cholesterol metabolism. Paeoniflorin ameliorates hyperlipidemia through multitarget mechanisms, potentially by suppressing the TREM-1-TLR4-NF-κB signaling pathway to reduce inflammation and by regulating cholesterol metabolism via the PCSK9-LDLR and LXRα-ABCG1 pathways. Full article

The role of bile acid metabolism within the skeletal muscle microenvironment in sarcopenia remains unclear. This study investigated bile acid alterations and the function of the ATP Binding Cassette Subfamily B Member 1 (ABCB1) transporter in muscle microvascular endothelial cells (MMECs) during aging. Using a sarcopenic mouse model stratified by muscle density, we found elevated deoxycholic acid (DCA) and lithocholic acid (LCA) levels but reduced tauroursodeoxycholic acid (TUDCA) levels in muscle, correlating with downregulated ABCB1/P-glycoprotein expression. In vitro, inhibition of ABCB1 in MMECs impaired bile acid efflux, promoted inflammation, and compromised endothelial health. Conditioned medium from these MMECs reduced the viability, proliferation, and differentiation of C2C12 myoblasts, downregulated myogenic factors, and increased atrophy markers. Furthermore, we identified miR-135a-5p as a direct upstream regulator of ABCB1 in MMECs, and demonstrated that it mediates bile acid efflux impairment and subsequent myoblast dysfunction. Our findings reveal a novel “bile acid–MMEC–muscle” axis in sarcopenia, where miR-135a-5p-mediated ABCB1 downregulation in MMECs disrupts the local bile acid milieu and impairs muscle regeneration, highlighting ABCB1 as a potential therapeutic target for aging-related muscle loss. Full article

Liver disease encompasses a wide range of conditions, each requiring tailored therapeutic approaches. This review describes and critically discusses treatments with robust evidence for improving liver health. Ursodeoxycholic acid (UDCA) is a drug approved by the Food and Drug Administration of the USA to treat primary biliary cholangitis (PBC). In addition, UDCA has been demonstrated to protect against metabolic dysfunction-associated steatohepatitis, fibrosis, and drug-induced liver injury (DILI). The mechanism of action of UDCA has been attributed not only to decreasing the effects of toxic bile acids but also to protecting mitochondrial integrity and function, as well as to antioxidant, anti-inflammatory, and anti-apoptotic activities. UDCA can scavenge reactive oxygen species (ROS) and activate the nuclear factor-E2-related factor-2 (Nrf2) pathway, thereby exerting antioxidant activity. The anti-inflammatory activity of UDCA is associated with its ability to inhibit the nuclear factor-κB pathway. Pirfenidone is a well-recognized antifibrotic drug for the treatment of idiopathic pulmonary fibrosis; its effects on liver fibrosis have also been demonstrated. Pirfenidone exerts anti-inflammatory effects by attenuating the nucleotide-binding oligomerization domain-like receptor 3 inflammasome signaling pathway. The antioxidant actions of pirfenidone are associated with its ability to upregulate the Nrf2 pathway. Both the anti-inflammatory and antioxidant properties of pirfenidone act together to attenuate lung and liver fibrosis, decreasing transforming growth factor-β levels, inhibiting profibrogenic hepatic stellate cell activation, and increasing extracellular matrix degradation. Methyltransferases utilize S-adenosyl-L-methionine (SAM) as a methyl donor for most transmethylation reactions in the body. SAM increases reduced glutathione (GSH) levels, exerting important antioxidant effects. Evidence indicates that SAM prevents fibrosis and attenuates hepatocellular carcinoma development, improving patient survival. N-acetylcysteine (NAC) is a precursor to L-cysteine and GSH and is used in clinical settings to treat cancer, nephropathy, heart disease, pulmonary fibrosis, polycystic ovary syndrome, and influenza. Regarding the liver, NAC is the most accepted treatment for DILI, especially after paracetamol overdose. Owing to its antioxidant and anti-inflammatory actions, NAC has been successfully used to treat chronic liver injuries, including hepatosteatosis and fibrosis. Therefore, ursodeoxycholic acid, pirfenidone, S-adenosyl-L-methionine, and N-acetylcysteine could represent therapeutic strategies for the treatment of liver pathologies. Full article

Rhizoma coptidis (RC), known as Huang Lian, is widely used for treating diabetes in Traditional Chinese Medicine. G protein-coupled bile acid receptor 1 (TGR5) is a potential therapeutic target for glucose-lipid metabolic disorders due to its capacity to stimulate glucagon-like peptide-1 (GLP-1) secretion. However, whether RC contains ingredients targeting TGR5 remains unclear. In this study, we screened 330 secondary metabolites of RC via molecular docking and identified obacunone as a top candidate. We confirmed binding using Cell Membrane Chromatography (CMC) and quantified affinity via Surface Plasmon Resonance (SPR), determining a KD of 101 μM. cAMP assays identified obacunone as an activator of TGR5. Subsequently, concentration-dependent cAMP assays characterized it as a partial agonist with an EC50 of 9.6 μM. Finally, transcriptomic profiling revealed a stress adaptation response, identifying Heme Oxygenase 1 (HMOX1) as the most significantly upregulated gene (padj = 9.99 × 10⁻⁷², log₂FoldChange = 1.65). These findings contribute to understanding the pharmacological profile of RC and provide a screening example for identifying components with GPCR activity in RC. Full article

Melatonin, an indolic neuromodulator with putative oncostatic and proposed anti-inflammatory properties, primarily demonstrated in preclinical models, is produced at extrapineal sites—most notably in the gut. Its canonical actions are mediated by high-affinity GPCRs (MT1/MT2) and by NQO2, a cytosolic enzyme with a melatonin-binding site (historically termed “MT3”). A growing body of work highlights a bidirectional interaction between the gut microbiota and host melatonin. We integrated two lines of work: (i) three clinical cohorts—cardiac arrhythmias (n = 111; 46–75 y), epilepsy (n = 77; 20–59 y), and stage III–IV solid cancers (25–79 y)—profiled with stool 16S rRNA sequencing, SCFA measurements, and circulating melatonin/urinary 6-sulfatoxymelatonin and (ii) an age-spanning cognitive cohort with melatonin phenotyping, microbiome analyses, and exploratory immune/metabolite readouts, including a novel observation of melatonin binding on bacterial membranes. Across all three disease cohorts, we observed moderate-to-severe dysbiosis, with reduced alpha-diversity and shifted beta-structure. The core dysbiosis implicated tryptophan-active taxa (Bacteroides/Clostridiales proteolysis and indolic conversions) and depletion of SCFA-forward commensals (e.g., Faecalibacterium, Blautia, Akkermansia, and several Lactobacillus/Bifidobacterium spp.). Synthesised literature indicates that typical human gut commensals rarely secrete measurable melatonin in vitro; rather, their metabolites (SCFAs, lactate, and tryptophan derivatives) regulate host enterochromaffin serotonin/melatonin production. In arrhythmia models, dysbiosis, bile-acid remodelling, and autonomic/inflammatory tone align with melatonin-sensitive antiarrhythmic effects. Epilepsy exhibits circadian seizure patterns and tryptophan–metabolite signatures, with modest and heterogeneous responses to add-on melatonin. Cancer cohorts show broader dysbiosis consistent with melatonin’s oncostatic actions. In the cognitive cohort, the absence of dysbiosis tracked with preserved learning across ages, and exploratory immunohistochemistry suggested melatonin-binding sites on bacterial membranes in ~15–17% of samples. A unifying microbiota–tryptophan–melatonin axis plausibly integrates circadian, electrophysiologic, and immune–oncologic phenotypes. Practical levers include fiber-rich diets (to drive SCFAs), light hygiene, and time-aware therapy, with indication-specific use of melatonin. Our conclusions regarding microbiota–melatonin crosstalk rely primarily on local paracrine effects within the gut mucosa (where melatonin concentrations are 10–400× plasma levels), whereas systemic chronotherapy conclusions depend on circulating melatonin amplitude and phase. This original research article presents primary data from four prospectively enrolled clinical cohorts (total n = 577). Full article

The rise of multidrug-resistant enteric pathogens and increased demand for antibiotic alternatives have intensified efforts to find reliable, safe, and effective probiotics. This study reports the isolation, characterization, and assessment of the probiotic potential of five Enterococcus strains isolated from the feces of healthy goats aged 7–9 months raised under conventional management. Following an initial screening of 57 lactic acid bacteria, 5 isolates (Enterococcus faecium, E. hirae, E. faecalis, Enterococcus sp., and Streptococcus lutetiensis) were chosen based on their catalase-negative, non-motile, and non-hemolytic characteristics, in addition to their high tolerance to gastric (pH 2.0) and intestinal (pH 8.0, 0.3–1.5% bile salt) stress. In simulated gastric juice, survival rates reached 89.05% (E5) and 85.03% (E3), while in intestinal juice, survival peaked at 78.01% (E4). All strains thrived in 4% NaCl and maintained at least 8 Log₁₀ CFU/mL after 12 h of exposure to 1.5% porcine bile salt. Cell surface hydrophobicity (0.78–93.85%) and auto-aggregation (23–91%) properties were strain-dependent, but exceeded the thresholds required for efficient gut colonization. Co-aggregation assays demonstrated over 45% binding with E. coli and S. typhimurium, suggesting a strong potential to displace pathogens. Cell-free supernatants created inhibition zones measuring 15.02 mm against E. coli and 11.04 mm against S. flexneri, while maintaining activity against methicillin-resistant S. aureus (MRSA). Antibiotic testing indicated that all strains were sensitive to ciprofloxacin and florfenicol. No β-hemolysis or mobile resistance genes were found, supporting the initial safety findings. This study reveals that Enterococcus isolates from goats display a unique combination of gastrointestinal survivability and broad-spectrum antipathogenic activity and, therefore, are promising candidates for the development of next-generation probiotic strains for use in livestock (and, potentially, humans). Further in vivo validation and genome-based safety assessments are warranted. Full article

Drug- and alcohol-induced liver injury involves impaired bile acids or bilirubin secretion, but it is not known how senescence influences the secretion of hepatocytes exposed to drugs and alcohol. In this study, the toxic effects of ritonavir, lopinavir, and alcohol on hepatocyte transporters and the secretion of bile acids and bilirubin were investigated in hydrogen peroxide-induced senescent HepG2 and doxorubicin-induced senescent primary human hepatocytes. In HepG2, intracellular conjugated bilirubin increased upon senescence and extracellular conjugated bilirubin in culture medium was decreased by ritonavir and lopinavir treatment. In the primary hepatocytes, intracellular bile acids or medium bilirubin were not significantly changed upon senescence. However, intracellular bile acids were increased, and medium conjugated bilirubin were decreased in senescent primary hepatocytes treated with alcohol and the two drugs. Transcriptional expressions of adenosine triphosphate (ATP)-binding cassette (ABC) transporters (ABCB4, ABCC6, ABCB11, and ABCD3) were decreased whereas UDP-glucuronosyltransferase (UGT1A1) was increased by ritonavir and lopinavir in senescent HepG2. In senescent primary hepatocytes, expressions of ABCB11, ABCC1, ABCC2, ABCC3, ABCC4, and ABCC6 were apparently reduced whereas UGT1A1 and the cytochrome P450 enzyme CYP7A1 were markedly increased by alcohol combined with ritonavir and lopinavir. Selective ABCC6 knockdown in the primary hepatocytes altered expressions of two senescence markers, Lamin A/C and cyclin-dependent kinase inhibitor CKI (p21), increased expressions of CYP7A1 and hydroxy methyl glutaryl-CoA reductase (HMGCR), and increased intracellular bile acids. Further, anti-cholestasis agents, ursodeoxycholic acid and glycyrrhizin, significantly ameliorated the impaired secretions of bile acids and bilirubin as well as reducing intracellular lipid accumulation and cell death caused by ritonavir, lopinavir, and alcohol in the primary hepatocytes with ABCC6 knockdown. These results indicate that senescence moderately impairs the ABC transporters of hepatocytes and secretion of bile acids or bilirubin, which become worse in the presence of the drugs and alcohol but could be improved by anti-cholestasis agents. Full article

Background/Objectives: This review integrates evolutionary, metabolic, genetic, and nutritional perspectives to explain how sterol-derived vitamin D pathways shape human physiology and inter-individual variability in vitamin D status. Methods: The literature on sterol and vitamin D metabolism across animals, plants, fungi, and algae was synthesized with data from metabolomics databases, genome-wide association studies, RNA-seq resources (including GTEx), structural biology, and functional genomics. Results: Vitamin D₂ and vitamin D₃ likely emerged early in evolution as non-enzymatic photochemical sterol derivatives and were later co-opted into a tightly regulated endocrine system in vertebrates. In humans, cytochrome P450 enzymes coordinate vitamin D activation and degradation and intersect with oxysterol production, thereby linking vitamin D signaling to cholesterol and bile acid metabolism. Tissue-specific gene expression and regulatory genetic variants, particularly in the genes DHCR7, CYP2R1, CYP27B1, and CYP27A1, contribute to population-level differences in vitamin D status and metabolic outcomes. Structural analyses reveal selective, high-affinity binding of 1,25-dihydroxyvitamin D₃ to VDR, contrasted with broader, lower-affinity ligand recognition by LXRs. Dietary patterns modulate nuclear receptor signaling through distinct yet convergent ligand sources, including cholesterol-derived oxysterols, oxidized phytosterols, and vitamin D₂ versus vitamin D₃. Conclusions: Sterol and vitamin D metabolism constitute an evolutionarily conserved, adaptable network shaped by UV exposure, enzymatic control, genetic variation, and diet. This framework explains inter-individual variability in vitamin D biology and illustrates how evolutionary and dietary modulation of sterol-derived ligands confers functional flexibility to nuclear receptor signaling in human health. Full article

Background: Progressive familial intrahepatic cholestasis (PFIC) describes a group of genetically heterogeneous disorders. Several mutations in the ATP-Binding Cassette Subfamily B Member 4 (ABCB4) gene have been confirmed to cause reduced phosphatidylcholine levels in bile, leading to a deficiency of biliary vesicles and instability of mixed in micelles. The disease spectrum ranges from PFIC type 3 (PFIC3) to milder conditions. Herein, we present a rare case of PFIC3 in a young woman, emphasizing the importance of early detection and management. Methods: The patient was diagnosed using next-generation sequencing, with genetic testing and analysis performed by the Chengdu Hua Chuang Testing Institute. Variant pathogenicity was evaluated according to the American College of Medical Genetics and Genomics guidelines and classified into five categories: pathogenic, likely pathogenic, uncertain significance, likely benign, and benign. Nomenclature was assigned following the Human Genome Variation Society standards. Results: Contrast-enhanced abdominal computed tomography demonstrated liver cirrhosis with marked splenomegaly. Histological examination of liver biopsy specimens using hematoxylin and eosin and Masson staining further confirmed cirrhotic changes. Genetic testing was subsequently performed and revealed a likely pathogenic variant, c.2757T > A (p. Tyr919Ter), in exon 22 of the ABCB4 gene, which was also detected in the patient’s mother but absent in her father. Finally, PFIC3 was diagnosed. Following initiation of ursodeoxycholic acid therapy, the patient showed moderate improvement in liver function tests, underscoring a clinical case with therapeutic implications. Conclusions: Molecular genetic analyses of ABCB4 are essential for the accurate diagnosis of PFIC3. Clinicians should consider cholestatic liver diseases, particularly PFIC, as a differential diagnosis in cases of liver cirrhosis with unknown etiology, especially in young patients who lack prior symptoms or a family history of liver disease. Full article

Nuclear receptors are ligand-activated transcription factors that, in response to lipophilic hormones, vitamins, and dietary lipids, regulate numerous aspects of mammalian physiology. Bile acid receptors represent well-defined targets for the development of novel therapeutic approaches for metabolic and inflammatory diseases. The farnesoid X receptor (FXR) was identified as an orphan steroid receptor-like nuclear receptor, and its activation is crucial in many physiological functions of the liver. A vital function of FXR is to influence the amount of bile acids in hepatocytes by reducing bile acid synthesis, stimulating the bile salt export pump, and inhibiting enterohepatic circulation, thereby protecting hepatocytes from toxic bile acid accumulation. FXR activation induces distinctive changes in circulating cholesterol in animal models and humans. We present an evaluation of the interaction of various obeticholic acid analogs and other bile salts by studying their binding energies and receptor-ligand interactions using AutoDock 4.2.6 software. The results open the possibility of using new alternatives by deriving structures at position 3 of the steroid nucleus. Full article

Objectives: This experiment investigated the response of carcass composition, digestive function, hepatic lipid metabolism, intestinal microbiota, and serum metabolomics to excessive or restrictive dietary energy in Ningxiang pigs. Methods: A total of 36 Ningxiang pigs (210 ± 2 d, 43.26 ± 3.21 kg) were randomly assigned to three treatments (6 pens of 2 piglets each) and fed a control diet (CON, digestive energy (DE) 13.02 MJ/kg,), excessive energy diet (EE, 15.22 MJ/kg), and restrictive energy diet (RE, DE 10.84 MJ/kg), respectively. Results: Results showed that EE significantly increased the apparent digestibility of crude protein and total energy (p < 0.01), as well as the activities of jejunum neutral protease and ileal lipase (p < 0.05). With the increase in energy level, the apparent digestibility of ash, dry matter, and ether extract significantly increased (p < 0.01). RE significantly increased high-density lipoprotein cholesterol (HDL-C) content, significantly decreased triglycerides (TG), free fatty acid (NEFA), and total cholesterol (TC) contents, and up-regulated lipoprotein lipase (LPL) mRNA expression in the liver (p < 0.05). EE significantly increased the hepatosomatic index, the contents of low-density lipoprotein cholesterol (LDL-C) and total bile acids (TBA), and significantly up-regulated the mRNA expression of lipogenic genes acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), and sterol regulatory element-binding protein-1C (SREBP-1C) in the liver (p < 0.05). The abundance of p_Firmicutes was significantly increased and the abundance of p_Bacteroidetes was significantly decreased in test groups, while the ratio of the two was significantly increased in the RE group (p < 0.05). EE also significantly increased the abundance of g_Clostridium_sensu_stricto_1 (p < 0.05). The identical serum differential metabolites between the EE and RE group belong to phosphatidylcholine (PC), mostly being up-regulated in the EE group and down-regulated in the RE group (p < 0.05), one of which was mapped to the pathway of glycerophospholipid metabolism (KEGG ID: C00157). The relative content of serum trimethylamine N-oxide (TMAO, a microbial metabolite) was significantly decreased in the EE group (p < 0.05). Conclusions: The findings suggest RE had no obvious negative effect on carcass traits of Ningxiang pigs. Apart from exacerbated body fat deposition, EE promoted fat accumulation in the liver by up-regulating the expression of lipogenic genes. Dietary energy changes affect hepatic bile acid metabolism, which may be mediated through the glycerophospholipid metabolism pathway, as well as disturbances in the gut microbiota. Full article

The proposed physiological roles of bile acids have expanded beyond the digestion of fats to encompass cell signaling via the activation of a variety of nuclear and plasma membrane receptors in multiple organ systems. The current in silico study was inspired by previous observations from our group and others that bile acids interact functionally with cardiac, pulmonary, and gastrointestinal muscarinic receptors and more recent work demonstrating allosteric binding of cholesterol, the parent molecule for bile acid synthesis, to M₁ muscarinic receptors (M₁R). Here, we computationally tested the hypothesis that bile acids can allosterically bind to M₁R and thereby modulate receptor activation. Utilizing de novo site identification by the ligand competitive saturation (SILCS) method, putative novel allosteric binding sites of bile acid targeting M₁R were identified. Molecular dynamics simulations were used to uncover the molecular details of the activation mechanism of M₁R due to agonist binding along with allosteric modulation of bile acids on M₁R activation. Allosteric binding of bile acids and their glycine and taurine conjugates to M₁R negatively impacts the activation process, findings consistent with recent reports that M₁R expression and activation inhibit colon cancer cell proliferation. Thus, bile acids may augment colon cancer risk by inhibiting the tumor suppressor actions of M₁R. When validated experimentally, these findings are anticipated to shed light on our understanding of how bile acids in the membrane microenvironment can allosterically modulate the function of M₁R and possibly other G protein-coupled receptors. Full article