Effects of bile acids and the bile acid receptor FXR agonist on the respiratory rhythm in the in vitro brainstem medulla slice of neonatal Sprague-Dawley rats

The bile acid metabolome in umbilical cord blood and meconium of healthy newborns: distinct characteristics and implications

Objective

To characterize the bile acid metabolomic profiles of umbilical cord blood and meconium in healthy newborns.

Methods

Fifteen healthy newborns, which born in the Obstetrics Department of the Affiliated Hospital of Southwest Medical University between July 1 and August 31, 2023, were selected as study subjects. Umbilical cord blood and meconium samples were collected, and bile acid metabolomics were analyzed using ultra-high performance liquid chromatography-tandem mass spectrometry.

Results

The ratio of primary to secondary bile acids in cord blood was significantly higher than in meconium [2.64 (2.49, 5.70) vs. 0.99 (0.37, 1.58), Z = -3.80, P < 0.05]. The ratio of unconjugated to conjugated bile acids was notably higher in cord blood than in meconium [0.14 (0.07, 0.18) vs. 0.01 (0.01, 0.04), Z = -3.88, P < 0.05]. The ratio of cholic acid to chenodeoxycholic acid in conjugated primary bile acids was significantly lower in cord blood than in meconium [0.59 (0.19, 0.75) vs. 2.21 (1.34, 3.04), Z = -4.21, P < 0.05], but the ratio of cholic acid to chenodeoxycholic acid in secondary bile acids was significantly higher in cord blood than in meconium [0.42 (0.21, 0.63) vs. 0.03 (0.01, 0.05), Z = -4.54, P < 0.05]. Only three primary bile acids (taurochenodeoxycholic acid, glycochenodeoxycholic acid, and glycochenodeoxycholic acid 3-glucoside in umbilical cord blood) were correlated with their downstream metabolites in meconium (with hyodesoxycholic acid (r = -0.66, P = 0.01), tauro-ω-muricholic acid (r = 0.52, P = 0.048) and ursodeoxycholic acid-7S (r = -0.53, P = 0.04), respectively). In meconium, most of primary bile acids were correlated with their downstream metabolites (P all < 0.05): cholic acid was positively correlated with 3-dehydrocholic acid, taurocholic acid was positively correlated with taurodeoxycholic acid and 3-dehydrocholic acid, glycocholic acid was positively correlated with 3-dehydrocholic acid, chenodeoxycholic acid was positively correlated with glycoursodeoxycholic acid, taurolithocholic acid, and 7-keto lithocholic acid and negatively correlated with isolithocholic acid. Taurochenodeoxycholic acid was positively correlated with taurohyodeoxycholic acid, tauroursodeoxycholic acid, glycoursodeoxycholic acid, taurolithocholic acid, tauro-ω-muricholic acid, and glycohyodeoxycholic acid, while glycochenodeoxycholic acid was positively correlated with tauroursodeoxycholic acid, glycoursodeoxycholic acid, taurolithocholic acid, and glycohyodeoxycholic acid, and negatively correlated with isolithocholic acid.

Conclusion

The bile acid metabolites in umbilical cord blood and meconium differ significantly, and the downstream bile acid metabolites in meconium are predominantly correlated with their upstream bile acids in meconium, but not those bile acids in umbilical cord blood. These findings contribute to a better understanding of bile acid metabolism in utero and lay the foundation for future research in this topic.

Metabolomics analysis reveals characteristic metabolites in different levels of oxaliplatin-induced neurotoxicity

Oxaliplatin (L-OHP), a third-generation platinum-based anti-tumor drug, finds widespread application in the first-line treatment of metastatic colorectal cancer. Despite its efficacy, the drug's usage is curtailed by a litany of side effects, with L-OHP-induced peripheral neuropathy (OIPN) being the most debilitating. This condition can be classified into varying degrees of severity. Employing serum metabolomics, a high-sensitivity, high-throughput technique, holds promise as a method to identify biomarkers for clinical assessment and monitoring of OIPN patients across different severity levels. In our study, we analyzed serum metabolites in patients with different OIPN levels using ultra-performance liquid chromatography-high resolution mass spectrometry. By employing statistical analyses and pathway enrichment studies, we aimed to identify potential biomarkers and metabolic pathways. Our findings characterized the serum metabolic profiles of patients with varying OIPN levels. Notably, pathway analysis revealed a significant correlation with lipid metabolism, amino acid metabolism, and energy metabolism. Multivariate statistical analysis and receiver operator characteristic curve evaluation pointed to anhalamine and glycochenodeoxycholic acid as potential biomarkers for OIPN C and A, which suggest that serum metabolomics may serve as a potent tool for exploring the metabolic status of patients suffering from diverse diseases and for discovering novel biomarkers.

Liver's influence on the brain through the action of bile acids

The liver partakes as a sensor and effector of peripheral metabolic changes and a regulator of systemic blood and nutrient circulation. As such, abnormalities arising from liver dysfunction can influence the brain in multiple ways, owing to direct and indirect bilateral communication between the liver and the brain. Interestingly, altered bile acid composition resulting from perturbed liver cholesterol metabolism influences systemic inflammatory responses, blood-brain barrier permeability, and neuron synaptic functions. Furthermore, bile acids produced by specific bacterial species may provide a causal link between dysregulated gut flora and neurodegenerative disease pathology through the gut-brain axis. This review will cover the role of bile acids-an often-overlooked category of active metabolites-in the development of neurological disorders associated with neurodegeneration. Further studies into bile acid signaling in the brain may provide insights into novel treatments against neurological disorders.

Role of Gut Microbiome in Atherosclerosis: Molecular and Therapeutic Aspects

Atherosclerosis is one of the most relevant and prevalent cardiovascular diseases of our time. It is one of the pathological entities that increases the morbidity and mortality index in the adult population. Pathophysiological connections have been observed between atherosclerosis and the gut microbiome (GM), represented by a group of microorganisms that are present in the gut. These microorganisms are vital for metabolic homeostasis in humans. Recently, direct and indirect mechanisms through which GM can affect the development of atherosclerosis have been studied. This has led to research into the possible modulation of GM and metabolites as a new target in the prevention and treatment of atherosclerosis. The goal of this review is to analyze the physiopathological mechanisms linking GM and atherosclerosis that have been described so far. We also aim to summarize the recent studies that propose GM as a potential target in atherosclerosis management.

Comprehensive analysis of placental gene-expression profiles and identification of EGFR-mediated autophagy and ferroptosis suppression in intrahepatic cholestasis of pregnancy

Intrahepatic cholestasis of pregnancy (ICP) was the most common liver disease specific to pregnancy. The symptoms of ICP were maternal pruritus and increased bile acid level in serum which was related to preterm birth, fetal distress, meconium-stained amniotic fluid and stillbirth. However, the mechanism of ICP progression on fetal development remained obscure. Sequencing data of 2 normal placenta samples and 4 intrahepatic cholestasis samples during pregnancy was analyzed by GEO2R. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used for analysis of differentially expressed genes. MCODE - A plug-in of Cytoscape was used for molecular complex detection. STRING, Cytoscape, GeneMANIA, NetworkAnalyst, TransmiR, JASPAR, DGIdb and DrugBank were used in this study. Furthermore, histopathological and cell experiments were used to verify our results. Our study identified the key KEGG pathway and four MCODEs which were closely with ICP development, further, sorted by degree centrality, we showed top 30 genes from 7209 differential genes, such as TP53, SRC, EGFR, ESR1, IL10, CD8A, MAPK3, PTPRC, EGF, KIT, ITGAM, LEP and CSF2, etc. Moreover, these hub genes participated in JAK-STAT3 signaling pathway and STAT1/3 regulated these genes expression in a direct way or miRNA-mediated manner. Drug-target analysis about up-regulated genes among hub genes showed that these genes contained multiple drug action site. Furthermore, hub gene-EGFR was associated with destroyed autophagy and ferroptosis. In conclusion, our study analyzed key genes and pathways in ICP development. JAK-STAT3 pathway and EGFR might be a potential target for ICP therapy.

Metabolic Diffusion in Neuropathologies: The Relevance of Brain-Liver Axis

Chronic liver diseases include a broad group of hepatic disorders from different etiologies and with varying degrees of progression and severity. Among them, non-alcoholic fatty (NAFLD) and alcoholic (ALD) liver diseases are the most frequent forms of expression, caused by either metabolic alterations or chronic alcohol consumption. The liver is the main regulator of energy homeostasis and metabolism of potentially toxic compounds in the organism, thus hepatic disorders often promote the release of harmful substances. In this context, there is an existing interconnection between liver and brain, with the well-named brain-liver axis, in which liver pathologies lead to the promotion of neurodegenerative disorders. Alzheimer's (AD) and Parkinson's (PD) diseases are the most relevant neurological disorders worldwide. The present work highlights the relevance of the liver-related promotion of these disorders. Liver-related hyperammonemia has been related to the promotion of perturbations in nervous systems, whereas the production of ketone bodies under certain conditions may protect from developing them. The capacity of the liver of amyloid-β (Aβ) clearance is reduced under liver pathologies, contributing to the development of AD. These perturbations are even aggravated by the pro-inflammatory state that often accompanies liver diseases, leading to the named neuroinflammation. The current nourishment habits, named as Western diet (WD) and alterations in the bile acid (BA) profile, whose homeostasis is controlled by the liver, have been also related to both AD and PD, whereas the supplementation with certain compounds, has been demonstrated to alleviate the pathologies.

Nitroalkene fatty acids modulate bile acid metabolism and lung function in obese asthma

Bile acid profiles are altered in obese individuals with asthma. Thus, we sought to better understand how obesity-related systemic changes contribute to lung pathophysiology. We also test the therapeutic potential of nitro-oleic acid (NO₂-OA), a regulator of metabolic and inflammatory signaling pathways, to mitigate allergen and obesity-induced lung function decline in a murine model of asthma. Bile acids were measured in the plasma of healthy subjects and individuals with asthma and serum and lung tissue of mice with and without allergic airway disease (AAD). Lung function, indices of inflammation and hepatic bile acid enzyme expression were measured in obese mice with house dust mite-induced AAD treated with vehicle or NO₂-OA. Serum levels of glycocholic acid and glycoursodeoxycholic acid clinically correlate with body mass index and airway hyperreactivity whereas murine levels of β-muricholic acid and tauro-β-muricholic acid were significantly increased and positively correlated with impaired lung function in obese mice with AAD. NO₂-OA reduced murine bile acid levels by modulating hepatic expression of bile acid synthesis enzymes, with a concomitant reduction in small airway resistance and tissue elastance. Bile acids correlate to body mass index and lung function decline and the signaling actions of nitroalkenes can limit AAD by modulating bile acid metabolism, revealing a potential pharmacologic approach to improving the current standard of care.

Redox-Dependent Effects in the Physiopathological Role of Bile Acids

Bile acids (BA) are recognized by their role in nutrient absorption. However, there is growing evidence that BA also have endocrine and metabolic functions. Besides, the steroidal-derived structure gives BA a toxic potential over the biological membrane. Thus, cholestatic disorders, characterized by elevated BA on the liver and serum, are a significant cause of liver transplant and extrahepatic complications, such as skeletal muscle, central nervous system (CNS), heart, and placenta. Further, the BA have an essential role in cellular damage, mediating processes such as membrane disruption, mitochondrial dysfunction, and the generation of reactive oxygen species (ROS) and oxidative stress. The purpose of this review is to describe the BA and their role on hepatic and extrahepatic complications in cholestatic diseases, focusing on the association between BA and the generation of oxidative stress that mediates tissue damage.

Liver Bile Acid Changes in Mouse Models of Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive cognitive impairment. It is hypothesized to develop due to the dysfunction of two major proteins, amyloid-β (Aβ) and microtubule-associated protein, tau. Evidence supports the involvement of cholesterol changes in both the generation and deposition of Aβ. This study was performed to better understand the role of liver cholesterol and bile acid metabolism in the pathophysiology of AD. We used male and female wild-type control (C57BL/6J) mice to compare to two well-characterized amyloidosis models of AD, APP/PS1, and App^NL-G-F. Both conjugated and unconjugated primary and secondary bile acids were quantified using UPLC-MS/MS from livers of control and AD mice. We also measured cholesterol and its metabolites and identified changes in levels of proteins associated with bile acid synthesis and signaling. We observed sex differences in liver cholesterol levels accompanied by differences in levels of synthesis intermediates and conjugated and unconjugated liver primary bile acids in both APP/PS1 and App^NL-G-F mice when compared to controls. Our data revealed fundamental deficiencies in cholesterol metabolism and bile acid synthesis in the livers of two different AD mouse lines. These findings strengthen the involvement of liver metabolism in the pathophysiology of AD.

Molecular Pathogenesis of Intrahepatic Cholestasis of Pregnancy

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disease. The maternal symptoms are characterized by skin pruritus and elevated bile acids, causing several adverse outcomes for fetuses, including an increased risk of preterm birth, meconium-stained amniotic fluid, neonatal depression, respiratory distress syndrome, and stillbirth. Genetic, hormonal, immunological, and environmental factors contribute to the pathogenesis of ICP, and the estrogen-bile acid axis is thought to play a dominant role. The advances in the past 10 years uncover more details of this axis. Moreover, dysregulation of extracellular matrix and oxygen supply, organelle dysfunction, and epigenetic changes are also found to cause ICP, illuminating more potential drug targets for interfering with. Here, we summarize the molecular pathogenesis of ICP with an emphasis on the advancement in the past 10 years, aiming to give an updated full view of this field.

Emodin Rescues Intrahepatic Cholestasis via Stimulating FXR/BSEP Pathway in Promoting the Canalicular Export of Accumulated Bile

Aim

Bile salt export pump (BSEP) have been confirmed to play an important role for bile acid canalicular export in the treatment of cholestasis. In this study, we investigated the stimulatory effect of emodin on BSEP signaling pathway in cholestasis.

Methods

Cell and animal experiments were given different concentrations of emodin. The BSEP upstream molecule farnesoid X receptor was down-regulated by small interfering RNA (siRNA) technology or guggulsterones and up-regulated by lentivirus or GW4064. Real-time PCR and Western blotting was employed to detect the mRNA and protein levels of BSEP in LO2 cell, rat primary hepatocytes and liver tissue. Immunohistochemistry (IHC) was used to examine the expression of BSEP in liver tissues. Rat liver function and pathological changes of liver tissue were performed by biochemical test and hematoxylin and eosin (HE) staining.

Results

Emodin could increase the mRNA and protein expression of BSEP and FXR. When down-regulating farnesoid X receptor expression with the siRNA or inhibitor guggulsterones, and up-regulating farnesoid X receptor expression with the lentivirus or agonist GW4064, emodin could increase the mRNA level of BSEP and FXR and the protein level of BSEP, FXR1, and FXR2. Emodin also had a notable effect on rat primary hepatocytes experiment, rat pathological manifestation, BSEP, FXR1, and FXR2 positive staining in liver tissues and the test of liver function.

Conclusion

Emodin has a protective effect and a rescue activity on cholestasis via stimulating FXR/BSEP pathways in promoting the canalicular export of accumulated bile.

Nutritional Modulation of Immune and Central Nervous System Homeostasis: The Role of Diet in Development of Neuroinflammation and Neurological Disease

The gut-microbiome-brain axis is now recognized as an essential part in the regulation of systemic metabolism and homeostasis. Accumulating evidence has demonstrated that dietary patterns can influence the development of metabolic alterations and inflammation through the effects of nutrients on a multitude of variables, including microbiome composition, release of microbial products, gastrointestinal signaling molecules, and neurotransmitters. These signaling molecules are, in turn, implicated in the regulation of the immune system, either promoting or inhibiting the production of pro-inflammatory cytokines and the expansion of specific leukocyte subpopulations, such as Th17 and Treg cells, which are relevant in the development of neuroinflammatory and neurodegenerative conditions. Metabolic diseases, like obesity and type 2 diabetes mellitus, are related to inadequate dietary patterns and promote variations in the aforementioned signaling pathways in patients with these conditions, which have been linked to alterations in neurological functions and mental health. Thus, maintenance of adequate dietary patterns should be an essential component of any strategy aiming to prevent neurological pathologies derived from systemic metabolic alterations. The present review summarizes current knowledge on the role of nutrition in the modulation of the immune system and its impact in the development of neuroinflammation and neurological disease.

Effects of corilagin on alleviating cholestasis via farnesoid X receptor-associated pathways in vitro and in vivo

BACKGROUND AND PURPOSE

The aim of this study was to investigate the ameliorative effects of corilagin on intrahepatic cholestasis induced by regulating liver farnesoid X receptor (FXR)-associated pathways in vitro and in vivo.

EXPERIMENTAL APPROACH

Cellular and animal models were treated with different concentrations of corilagin. In the cellular experiments, FXR expression was up-regulated by either lentiviral transduction or GW4064 treatment and down-regulated by either siRNA technology or treatment with guggulsterones. Real-time PCR and Western blotting were employed to detect the mRNA and protein levels of FXR, SHP1, SHP2, UGT2B4, BSEP, CYP7A1, CYP7B1, NTCP, MRP2 and SULT2A1. Immunohistochemistry was used to examine the expression of BSEP in liver tissues. Rat liver function and pathological changes in hepatic tissue were assessed using biochemical tests and haematoxylin and eosin staining.

RESULTS

Corilagin increased the mRNA and protein levels of FXR, SHP1, SHP2, UGT2B4, BSEP, MRP2 and SULT2A1, and decreased those of CYP7A1, CYP7B1 and NTCP. After either up- or down-regulating FXR using different methods, corilagin could still increase the mRNA and protein levels of FXR, SHP1, SHP2, UGT2B4, BSEP, MRP2 and SULT2A1 and decrease the protein levels of CYP7A1, CYP7B1 and NTCP, especially when administered at a high concentration. Corilagin also exerted a notable effect on the pathological manifestations of intrahepatic cholestasis, BSEP staining in liver tissues and liver function.

CONCLUSIONS AND IMPLICATIONS

Corilagin exerts a protective effect in hepatocytes and can prevent the deleterious activities of intrahepatic cholestasis by stimulating FXR-associated pathways.

Z-Guggulsterone Produces Antidepressant-Like Effects in Mice through Activation of the BDNF Signaling Pathway

BACKGROUND

Z-guggulsterone, an active compound extracted from the gum resin of the tree Commiphora mukul, has been shown to improve animal memory deficits via activating the brain-derived neurotrophic factor signaling pathway. Here, we investigated the antidepressant-like effect of Z-guggulsterone in a chronic unpredictable stress mouse model of depression.

METHODS

The effects of Z-guggulsterone were assessed in mice with the tail suspension test and forced swimming test. Z-guggulsterone was also investigated in the chronic unpredictable stress model of depression with fluoxetine as the positive control. Changes in hippocampal neurogenesis as well as the brain-derived neurotrophic factor signaling pathway after chronic unpredictable stress/Z-guggulsterone treatment were investigated. The tryptophan hydroxylase inhibitor and the tyrosine kinase B inhibitor were also used to explore the antidepressant-like mechanisms of Z-guggulsterone.

RESULTS

Z-guggulsterone (10, 30 mg/kg) administration protected the mice against the chronic unpredictable stress-induced increases in the immobile time in the tail suspension test and forced swimming test and also reversed the reduction in sucrose intake in sucrose preference experiment. Z-guggulsterone (10, 30 mg/kg) administration prevented the reductions in brain-derived neurotrophic factor protein expression levels as well as the phosphorylation levels of cAMP response element binding protein, extracellular signal-regulated kinase 1/2, and protein kinase B in the hippocampus and cortex induced by chronic unpredictable stress. Z-guggulsterone (10, 30 mg/kg) treatment also improved hippocampal neurogenesis in chronic unpredictable stress-treated mice. Blockade of the brain-derived neurotrophic factor signal, but not the monoaminergic system, attenuated the antidepressant-like effects of Z-guggulsterone.

CONCLUSIONS

Z-guggulsterone exhibits antidepressant activity via activation of the brain-derived neurotrophic factor signaling pathway and upregulation of hippocampal neurogenesis.

Effects of bile acids on neurological function and disease

Bile acids are synthesized from cholesterol and are known to be involved with the emulsification and digestion of dietary lipids and fat-soluble vitamins. Outside of this role, bile acids can act as cell signaling effectors through binding and activating receptors on both the cell membrane and nucleus. Numerous reports have investigated these signaling pathways in conditions where the liver is damaged. More recently, effort has been made to investigate the role of bile acids in diseases outside of those associated with liver damage. This review summarizes recent findings on the influences that bile acids can exert in normal neurological function and their contribution to diseases of the nervous system, with the intent of highlighting the role of these metabolites as potential players in neurological disorders.-McMillin, M., DeMorrow, S. Effects of bile acids on neurological function and disease.

Morphologic Damage of Rat Alveolar Epithelial Type II Cells Induced by Bile Acids Could Be Ameliorated by Farnesoid X Receptor Inhibitor Z-Guggulsterone In Vitro

Objective. To determine whether bile acids (BAs) affect respiratory functions through the farnesoid X receptor (FXR) expressed in the lungs and to explore the possible mechanisms of BAs-induced respiratory disorder. Methods. Primary cultured alveolar epithelial type II cells (AECIIs) of rat were treated with different concentrations of chenodeoxycholic acid (CDCA) in the presence or absence of FXR inhibitor Z-guggulsterone (GS). Then, expression of FXR in nuclei of AECIIs was assessed by immunofluorescence microscopy. And ultrastructural changes of the cells were observed under transmission electron microscope and analyzed by Image-Pro Plus software. Results. Morphologic damage of AECIIs was exhibited in high BAs group in vitro, with high-level expression of FXR, while FXR inhibitor GS could attenuate the cytotoxicity of BAs to AECIIs. Conclusions. FXR expression was related to the morphologic damage of AECIIs induced by BAs, thus influencing respiratory functions.

Intrahepatic cholestasis of pregnancy: Recent advances

Intrahepatic cholestasis of pregnancy, also known as obstetric cholestasis, is a pruritic condition of pregnancy characterized by an underlying elevation in circulating bile acids and liver derangement, and associated with adverse fetal outcomes, such as preterm labor and stillbirth. Limited understanding of the underlying pathophysiology and mechanisms involved in adverse outcomes has previously restricted treatment options and pregnancy management. Recent advances in these research fields provide tantalizing targets to improve the care of pregnant women affected by this condition.

Guggulsterone and Its Role in Chronic Diseases

Guggulsterone is a plant sterol derived from gum resin of Commiphora wightii. The gum resin from guggul plants has been used for thousand years in Ayurveda to treat various disorders, including internal tumors, obesity, liver disorders, malignant sores and ulcers, urinary complaints, intestinal worms, leucoderma, sinuses, edema, and sudden paralytic seizures. Guggulsterone has been identified a bioactive components of this gum resin. This plant steroid has been reported to work as an antagonist of certain nuclear receptors, especially farnesoid X receptor, which regulates bile acids and cholesterol metabolism. Guggulsterone also mediates gene expression through the regulation of transcription factors, including nuclear factor-kappa B and signal transducer and activator of transcription 3, which plays important roles in the development of inflammation and tumorigenesis. Guggulsterone has been shown to downregulate the expression of proteins involved in anti-apoptotic, cell survival, cell proliferation, angiogenic, metastatic, and chemoresistant activities in tumor cells. This review aimed to clarify the cell signal pathways targeted by guggulsterone and the bioactivities of guggulsterone in animal models and humans.