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Cyclosporine-A (CsA) is currently used to treat immune rejection after organ transplantation as a commonly used immunosuppressant. Liver injury is one of the most common adverse effects of CsA, whose precise mechanism has not been fully elucidated. Pregnane X receptor (PXR) plays a critical role in mediating drug-induced liver injury as a key regulator of drug and xenobiotic clearance. As a nuclear receptor, PXR transcriptionally upregulates the expression of drug-metabolizing enzymes and drug transporters, including cytochrome P4503A (CPY3A) and multidrug resistance-associated protein 2 (MRP2). Our study established CsA-induced cytotoxic hepatocytes in an in vitro model, demonstrating that CsA dose-dependently increased the aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) level secreted in the HepG2 cell supernatant, as well as viability and oxidative stress of HepG2 cells. CsA also dose-dependently decreased the PXR, CYP3A4, CPY3A5, and MRP2 levels of HepG2 cells. Mechanistically, altering the expression of PXR, CYP3A4, CYP3A5, and MRP2 affected the impact of CsA on AST and LDH levels. Moreover, altering the expression of PXR also changed the level of CYP3A4, CPY3A5, and MRP2 of HepG2 cells treated by CsA. Our presented findings provide experimental evidence that CsA-induced liver injury is PXR tightly related. We suggest that PXR represents an attractive target for therapy of liver injury due to its central role in the regulation of the metabolizing enzymes CYP3A and MRP2-mediated bile acid transport and detoxification. [ABSTRACT FROM AUTHOR]

Hepatocyte nuclear factor 4 alpha (HNF4α) and the pregnane X receptor (PXR) are involved in hepatocyte regeneration. It is not clear whether HNF4α is involved in hepatocyte regeneration through the regulation of PXR. This study aims to explore the regulatory relationship between HNF4a and PXR, and whether it affects hepatocyte regeneration. A mouse PXR gene reporter and an HNF4α overexpression plasmid were constructed and transfected into mouse hepatoma cells (Hepa1‐6). Overexpression of HNF4α, detection of the PXR gene reporter fluorescence value, PXR gene, and protein expression analysis were conducted to explore the regulatory relationship between HNF4α and PXR. Apoptosis and cell cycle data were measured to verify whether HNF4α is involved in hepatocyte regeneration through PXR. The luciferase gene reporter assay results indicated when HNF4α was overexpressed, the fluorescence value of the PXR gene reporter was higher than that in the control at 24 h. With increasing HNF4α expression, the PXR gene and protein expression increased, indicating that HNF4α binds to the PXR promoter and upregulates PXR expression. Apoptosis and cell cycle analysis results demonstrated that when the expression of HNF4α increased, the expression of PXR increased, the apoptosis rate decreased, and the proliferation rate increased. Meanwhile, when the upward trend of PXR gene expression was inhibited by ketoconazole, the proliferation rate decreased. By inhibiting HNF4α and creating a partial hepatectomy (PHx), we demonstrated that HNF4α can upregulate PXR to promote liver regeneration in vivo. Therefore, HNF4α is shown to improve hepatocyte regeneration by upregulating PXR, which provides a reference for future research on the combined application of drugs for the treatment of liver injury. [ABSTRACT FROM AUTHOR]

The interaction between herbal remedies and drugs is a fascinating phenomenon that might cause therapeutic complications in patients. Warfarin is an anticoagulant drug that provides anti-blood-clotting effects by inhibiting the formation of vitamin K-dependent coagulation factors, and warfarin interacts with the nuclear receptor PXR, subsequently modulating cytochrome P450 during the metabolism process. St. John's wort, an herbal medicine with antidepressant effects, can alter the pharmacokinetics of warfarin. Thymoquinone is one of the active compounds in N. sativa and has pharmacological activities such as anticoagulant, antidiabetic, diuretic, antidepressant, and anti-inflammatory effects. In this study, we investigated the compounds in Nigella sativa ( N. sativa) against pregnane X receptor (PXR) and evaluated the impact of thymoquinone (TQ) administration on PXR expression in HepG2 cells. The molecular docking analysis was conducted utilizing the Molecular Operating Environment (MOE) with the PXR (PDB ID: 7AXJ). At the same time, the PXR gene expression was measured using RT-PCR instruments. The RMSD value in docking represents the deviation criteria between the native ligand position and the redocking position result, indicating the capability of MOE and PDB qualification for performing molecular docking. The docking analysis showed that warfarin had the strongest binding energy (7AXJ -6.0507) by forming hydrogen binding type on Arg410. Despite TQ being the major component, it also displayed a high affinity for the two PDB IDs (7AXJ -4.5962). Furthermore, the concurrent administration of warfarin and TQ (19.27 μM) in HepG2 cells showed a significant reduction in the relative mRNA expression of the PXR gene. Given the above-mentioned findings, our study adequately enables us to predict the mechanism behind herb-drug interactions (HDIs) implicating N. sativa, specifically the TQ compound to warfarin metabolism via the activation of the PXR receptor. [ABSTRACT FROM AUTHOR]

AbstractOsteosarcoma (OS) is a prevalent malignancy among adolescents, commonly manifesting during childhood and adolescence. It exhibits a high degree of malignancy, propensity for metastasis, rapid progression, and poses challenges in clinical management. Chemotherapy represents an efficacious therapeutic modality for OS treatment. However, chemotherapy resistance of OS is a major problem in clinical treatment. In order to treat OS effectively, it is particularly important to explore the mechanism of chemotherapy resistance in OS.The Pregnane X receptor (PXR) is a nuclear receptor primarily involved in the metabolism, transport, and elimination of xenobiotics, including chemotherapeutic agents. PXR involves three stages of drug metabolism: stage I: drug metabolism enzymes; stage II: drug binding enzyme; stage III: drug transporter.PXR has been confirmed to be involved in the process of chemotherapy resistance in malignant tumors. The expression of PXR is increased in OS, which may be related to drug resistance of OS. Therefore, wereviewed in detail the role of PXR in chemotherapy drug resistance in OS. [ABSTRACT FROM AUTHOR]

Background: Myocardial infarction (MI) has emerged as the primary cause of global mortality. Managing blood sugar levels could play a vital role in the treatment of MI. Dapagliflozin (DPG), a commonly used hypoglycemic drug, has demonstrated efficacy in treating heart failure. However, the impact of DPG on MI remains unclear. We aimed to investigate the effects and mechanisms of DPG in relation to MI. Methods and results: DPG administration alleviated MI-induced cardiac dysfunction and myocardial fibrosis. We also found that DPG administration mitigated cardiomyocyte apoptosis through TUNEL staining. CD31 and α-Sma staining revealed that DPG promotes post-MI angiogenesis in mice. In vitro, using scratch assays, transwell assays, and tube formation assays, we discovered that DPG enhanced HUVEC proliferation capacity. Mechanistically, DPG promoted the expression of extracellular matrix genes and mitochondrial function-related genes. Additionally, molecular docking identified the interaction between DPG and PXR, which activated PXR and recruited it to the promoters of Pgam2 and Tcap, promoting their expressions, thus facilitating angiogenesis and post-MI heart repair. Conclusions: DPG promotes angiogenesis by activating PXR, thereby alleviating cardiac dysfunction and fibrosis after myocardial infarction. This study provides new strategies and targets for the treatment of ischemic disease.

Per- and poly-fluoroalkyl substances (PFAS) are a large class of fluorinated carbon chains that include legacy PFAS, such as perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorohexane sulfonate (PFHxS). These compounds induce adverse health effects, including hepatotoxicity. Potential alternatives to the legacy PFAS (HFPO-DA (GenX), HFPO4, HFPO-TA, F-53B, 6:2 FTSA, and 6:2 FTCA), as well as a byproduct of PFAS manufacturing (Nafion BP2), are increasingly being found in the environment. The potential hazards of these new alternatives are less well known. To better understand the diversity of molecular targets of the PFAS, we performed a comparative toxicogenomics analysis of the gene expression changes in the livers of mice exposed to these PFAS, and compared these to five activators of PPARα, a common target of many PFAS. Using hierarchical clustering, pathway analysis, and predictive biomarkers, we found that most of the alternative PFAS modulate molecular targets that overlap with legacy PFAS. Only three of the 11 PFAS tested did not appreciably activate PPARα (Nafion BP2, 6:2 FTSA, and 6:2 FTCA). Predictive biomarkers showed that most PFAS (PFHxS, PFOA, PFOS, PFNA, HFPO-TA, F-53B, HFPO4, Nafion BP2) activated CAR. PFNA, PFHxS, PFOA, PFOS, HFPO4, HFPO-TA, F-53B, Nafion BP2, and 6:2 FTSA suppressed STAT5b, activated NRF2, and activated SREBP. There was no apparent relationship between the length of the carbon chain, type of head group, or number of ether linkages and the transcriptomic changes. This work highlights the similarities in molecular targets between the legacy and alternative PFAS. [ABSTRACT FROM AUTHOR]

Pregnane X receptor (PXR) is a ligand-activated nuclear receptor that transcriptionally upregulates drug-metabolizing enzymes [e.g., cytochrome P450 3A4 (CYP3A4)] and transporters. Although the regulation of PXR target genes is well-characterized, less is known about the regulation of PXR protein level. By screening an RNAi library, we identified the F-box-only protein 44 (FBXO44) as a novel E3 ligase for PXR. PXR abundance increases upon knockdown of FBXO44, and, inversely, decreases upon overexpression of FBXO44. Further analysis revealed that FBXO44 interacts with PXR, leading to its ubiquitination and proteasomal degradation, and we determined that the F-box associated domain of FBXO44 and the ligand binding domain of PXR are required for the functional interaction. In summary, FBXO44 regulates PXR protein abundance, which has downstream consequences for CYP3A4 levels and drug–drug interactions. The results of this study provide new insight into the molecular mechanisms that regulate PXR protein level and activity and suggest the importance of considering how modulating E3 ubiquitin ligase activities will affect PXR-mediated drug metabolism.

Pharmaceuticals and environmental contaminants contribute to hypercholesterolemia. Several chemicals known to cause hypercholesterolemia, activate pregnane X receptor (PXR). PXR is a nuclear receptor, classically identified as a sensor of chemical environment and regulator of detoxification processes. Later, PXR activation has been shown to disrupt metabolic functions such as lipid metabolism and recent findings have shown PXR activation to promote hypercholesterolemia through multiple mechanisms. Hypercholesterolemia is a major causative risk factor for atherosclerosis and greatly promotes global health burden. Metabolic disruption by PXR activating chemicals leading to hypercholesterolemia represents a novel toxicity pathway of concern and requires further attention. Therefore, we constructed an adverse outcome pathway (AOP) by collecting the available knowledge considering the molecular mechanisms for PXR-mediated hypercholesterolemia. AOPs are tools of modern toxicology for systematizing mechanistic knowledge to assist health risk assessment of chemicals. AOPs are formalized and structured linear concepts describing a link between molecular initiating event (MIE) and adverse outcome (AO). MIE and AO are connected via key events (KE) through key event relationships (KER). We present a plausible route of how PXR activation (MIE) leads to hypercholesterolemia (AO) through direct regulation of cholesterol synthesis and via activation of sterol regulatory element binding protein 2-pathway. [ABSTRACT FROM AUTHOR]

Pregnane X receptor (PXR) is a ligand-activated nuclear receptor that transcriptionally upregulates drug-metabolizing enzymes [ e. g., cytochrome P450 3A4 (CYP3A4)] and transporters. Although the regulation of PXR target genes is well-characterized, less is known about the regulation of PXR protein level. By screening an RNAi library, we identified the F-box-only protein 44 (FBXO44) as a novel E3 ligase for PXR. PXR abundance increases upon knockdown of FBXO44, and, inversely, decreases upon overexpression of FBXO44. Further analysis revealed that FBXO44 interacts with PXR, leading to its ubiquitination and proteasomal degradation, and we determined that the F-box associated domain of FBXO44 and the ligand binding domain of PXR are required for the functional interaction. In summary, FBXO44 regulates PXR protein abundance, which has downstream consequences for CYP3A4 levels and drug–drug interactions. The results of this study provide new insight into the molecular mechanisms that regulate PXR protein level and activity and suggest the importance of considering how modulating E3 ubiquitin ligase activities will affect PXR-mediated drug metabolism. PXR is a xenobiotic receptor that controls the expression of drug-metabolizing enzymes and transporters. FBXO44 was identified as an E3 ligase that regulates PXR protein level by targeting PXR for ubiquitination and proteasomal degradation. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, hydroethanolic extracts of 30 top-selling botanicals (herbs) commonly used as ingredients of herbal dietary supplements in the US were screened for their potential to activate the human pregnane X receptor (hPXR) and human aryl hydrocarbon receptor (hAhR) and to increase the activities of hPXR- and hAhR-regulated drug metabolizing cytochrome P450 enzymes (i.e., CYP3A4 and CYP1A2, respectively). Of the 30 botanicals tested, 21 induced PXR and 29 induced AhR transcriptional activities. Out of the 21 botanicals that induced hPXR transcriptional activity, 14 yielded >50% induction in CYP3A4 activity at concentrations ranging from 6 to 60 µg/mL and 16 out of the 29 botanicals that activated hAhR yielded >50% induction in CYP1A2 activity at concentrations ranging from 3 to 30 µg/mL. Moreover, eight botanicals (G. gummi-gutta [garcinia], Hemp [low and high CBD content], H. perforatum [St. John's wort], M. vulgare [horehound], M. oleifera [moringa], O. vulgare [oregano], P. johimbe [yohimbe] and W. somnifera [ashwagandha]) yielded >50% induction in both CYP3A4 and CYP1A2 activity. Herbal products are mixtures of phytoconstituents, any of which could modulate drug metabolism. Our data reveals that several top-selling botanicals may pose herb-drug interaction (HDI) risks via CYP450 induction. While in vitro experiments can provide useful guidance in assessing a botanical's HDI potential, their clinical relevance needs to be investigated in vivo. Botanicals whose effects on hPXR/CYP3A4, and hAhR/CYP1A2 activity were most pronounced will be slated for further clinical investigation. [ABSTRACT FROM AUTHOR]

Aim: To summarize the state-of-the-art data on the molecular mechanisms of bile acid (BA) synthesis and absorption, their impaired absorption and receptor-dependent signaling, as well as on the effects of the gut microbiota on BA metabolism in inflammatory bowel diseases (IBD). Key messages: BA malabsorption is one of the relevant mechanisms in the development of diarrhea in IBD. It may occur due to various disorders of the ileum, such as terminal ileitis, ileocolitis or ileocecal resection in Crohn's disease and ileoanal reservoir in ulcerative colitis. Molecular mechanisms of BA malabsorption in IBD are related to a defect in the BA uptake by the apical sodium dependent bile acid transporter (ASBT), as well as to a decrease in the expression of pregnane X receptor (PXR) and farnesoid X receptor (FXR), whose activation by glucocorticoids results in an increase in the BA reabsorption in the ileum and a decrease in hologenic diarrhea. The metabolic profile of luminal BA in IBD is characterized by an increased content of conjugated and 3-OH-sulfated BA and reduced levels of secondary BA. The decrease in the relative abundance of the Lachnospiraceae and Oscillospiraceae spp. in IBD patients leads to a decrease in the efficiency of microbial biotransformation of BA. Changes in the BA metabolic profile in IBD affect the gut microbiota, and impaired interaction with the FXR, PXR, G protein-coupled bile acid receptor (GPBAR1), retinoid-related orphan receptors (RORs) and vitamin D receptor (VDR) results in a pro-inflammatory response and increased intestinal permeability, bacterial translocation, and IBD progression. BA metabolism in IBD-associated primary sclerosing cholangitis (PSC-IBD) is characterized by a significant decrease in the luminal BA pool, and the microbiota composition is remarkable for an increase in the relative abundance of Fusobacterium and Ruminococcus spp., and a decrease in Veillonella, Dorea, Blautia, Lachnospira and Roseburia. Conclusion: Disordered synergistic interplay of BA with intestinal microbiota results in disruption of the ligand-receptor interaction and BA metabolic transformation, which contributes to the activation of the immune system, formation of a vicious circle of chronic inflammation and IBD progression. Further studies into mutual influence of the gut microbiota, BA metabolism and receptor signaling may promote the development of new methods for the diagnosis and treatment of IBD.

Objective To investigate the expression and significance of progesterone X receptor (PXR), multidrug resistant protein 1 (MDR1), cytochrome P450 3A5 (CYP3A5), and cytochrome P450 2B6 (CYP2B6) in high-grade serous ovarian cancer (HGSOC). Methods A total of 56 patients with HGSOC admitted to the Department of Gynecology, Qingdao Municipal Hospital from September 2019 to December 2021 were included in the experimental group. The patients were further divided into drug resistant group (24 cases) and sensitive group (32 cases) according to their resistance to platinum chemotherapy drugs. The control group included 16 patients with uterine fibroids admitted during the same period. The expression of PXR, MDR1, CYP3A5, and CYP2B6 in HGSOC and normal fallopian tubes were determined by immunohistochemistry, real-time quantitative PCR, and Western blotting. Results Compared with the control group, the positive expression rates of PXR, MDR1, CYP3A5, and CYP2B6 were significantly increased in the experimental group (χ2=12.879-17.174,P0.05). Conclusion PXR, MDR1, CYP3A5, and CYP2B6 are highly expressed in HGSOC, which may be involved in its occurrence and development. The detection of PXR, MDR1, CYP3A5, and CYP2B6 expression can be used to determine the sensitivity of HGSOC to chemotherapy, which is helpful to provide guidance for postoperative chemotherapy.

Objective: Both obesity and exposure to chemicals may induce non-alcoholic fatty liver disease (NAFLD). Pregnane X Receptor (PXR) is a central target of metabolism disrupting chemicals and disturbs hepatic glucose and lipid metabolism. We hypothesized that the metabolic consequences of PXR activation may be modified by existing obesity and associated metabolic dysfunction. Methods: Wildtype and PXR knockout male mice were fed high-fat diet to induce obesity and metabolic dysfunction. PXR was activated with pregnenolone-16α-carbonitrile. Glucose metabolism, hepatosteatosis, insulin signaling, glucose uptake, liver glycogen, plasma and liver metabolomics, and liver, white adipose tissue, and muscle transcriptomics were investigated. Results: PXR activation aggravated obesity-induced liver steatosis by promoting lipogenesis and inhibiting fatty acid disposal. Accordingly, hepatic insulin sensitivity was impaired and circulating alanine aminotransferase level increased. Lipid synthesis was facilitated by increased liver glucose uptake and utilization of glycogen reserves resulting in dissociation of hepatosteatosis and hepatic insulin resistance from the systemic glucose tolerance and insulin sensitivity. Furthermore, glucagon-induced hepatic glucose production was impaired. PXR deficiency did not protect from the metabolic manifestations of obesity, but the liver transcriptomics and metabolomics profiling suggest diminished activation of inflammation and less prominent changes in the overall metabolite profile. Conclusions: Obesity and PXR activation by chemical exposure have a synergistic effect on NAFLD development. To support liver fat accumulation the PXR activation reorganizes glucose metabolism that seemingly improves systemic glucose metabolism. This implies that obese individuals, already predisposed to metabolic diseases, may be more susceptible to harmful metabolic effects of PXR-activating drugs and environmental chemicals.

Developmental exposure to the persistent environmental pollutant, polybrominated diphenyl ethers (PBDEs), is associated with increased diabetes prevalence. The microbial tryptophan metabolite, indole-3-propionic acid (IPA), is associated with reduced risk of type 2 diabetes and lower-grade inflammation and is a pregnane X receptor (PXR) activator. To explore the role of IPA in modifying the PBDE developmental toxicity, we orally exposed humanized PXR-transgenic (hPXR-TG) mouse dams to vehicle, 0.1 mg/kg/day DE-71 (an industrial PBDE mixture), DE-71+IPA (20 mg/kg/day), or IPA, from 4 weeks preconception to the end of lactation. Pups were weaned at 21 days of age and IPA supplementation continued in the corresponding treatment groups. Tissues were collected at various ages until 6 months of age (n  = 5 per group). In general, the effect of maternal DE-71 exposure on the gut microbiome of pups was amplified over time. The regulation of hepatic cytokines and prototypical xenobiotic-sensing transcription factor target genes by DE-71 and IPA was age- and sex-dependent, where DE-71-mediated mRNA increased selected cytokines (Il10, Il12p40, Il1β [both sexes], and [males]). The hepatic mRNA of the aryl hydrocarbon receptor (AhR) target gene Cyp1a2 was increased by maternal DE-71 and DE-71+IPA exposure at postnatal day 21 but intestinal Cyp1a1 was not altered by any of the exposures and ages. Maternal DE-71 exposure persistently increased serum indole, a known AhR ligand, in age- and sex-dependent manner. In conclusion, maternal DE-71 exposure produced a proinflammatory signature along the gut-liver axis, including gut dysbiosis, dysregulated tryptophan microbial metabolism, attenuated PXR signaling, and elevated AhR signaling in postweaned hPXR-TG pups over time, which was partially corrected by IPA supplementation. [ABSTRACT FROM AUTHOR]

The dried roots and rhizomes of Glycyrrhiza species (G. glabra, G. uralensis and G. inflata), commonly known as licorice, have long been used in traditional medicine. In addition, two other species, G. echinata and G. lepidota are also considered "licorice" in select markets. Currently, licorice is an integral part of several botanical drugs and dietary supplements. To probe the botanicals' safety, herb-drug interaction potential of the hydroethanolic extracts of five Glycyrrhiza species and their key constituents was investigated by determining their effects on pregnane X receptor, aryl hydrocarbon receptor, two major cytochrome P450 isoforms (CYP3A4 and CYP1A2), and the metabolic clearance of antiviral drugs. All extracts enhanced transcriptional activity of PXR and AhR (>2-fold) and increased the enzyme activity of CYP3A4 and CYP1A2. The highest increase in CYP3A4 was seen with G. echinata (4-fold), and the highest increase in CYP1A2 was seen with G. uralensis (18-fold) and G. inflata (16-fold). Among the constituents, glabridin, licoisoflavone A, glyasperin C, and glycycoumarin activated PXR and AhR, glabridin being the most effective (6- and 27-fold increase, respectively). Licoisoflavone A, glyasperin C, and glycycoumarin increased CYP3A4 activity while glabridin, glyasperin C, glycycoumarin, and formononetin increased CYP1A2 activity (>2-fold). The metabolism of antiretroviral drugs (rilpivirine and dolutegravir) was increased by G. uralensis (2.0 and 2.5-fold) and its marker compound glycycoumarin (2.3 and 1.6-fold). The metabolism of dolutegravir was also increased by G. glabra (2.8-fold) but not by its marker compound, glabridin. These results suggest that licorice and its phytochemicals could affect the metabolism and clearance of certain drugs that are substrates of CYP3A4 and CYP1A2. [ABSTRACT FROM AUTHOR]

Background and Aims: Barrett's esophagus (BE) is the precursor lesion for esophageal adenocarcinoma (EAC). To detect EAC in early stage, patients with BE undergo endoscopic surveillance. Surveillance cohorts largely consist of nondysplastic BE (NDBE) patients with a low annual progression risk (

Atorvastatin (ATV) is a hypolipidemic drug widely detected in the aquatic environment. Nevertheless, limited information is provided about the toxic effects of ATV on estuary or coastal species and the underlying mechanisms. In the present study, the responses of genes expression in pregnane X receptor (PXR) signaling pathway and enzymatic activities in the liver of the estuarine benthic fish (Mugilogobius chulae) were investigated under acute and sub-chronic ATV exposure. Results showed that PXR was significantly inhibited in the highest exposure concentration of ATV for a shorter time (24 h, 500 μg L−1) but induced in a lower concentration (72 h, 5 μg L−1). The downstream genes in PXR signaling pathway such as CYP3A, SULT, UGT, and GST showed similar trends to PXR. P-gp and MRP1 were repressed in most treatments. GCLC associated with GSH synthesis was mostly induced under ATV exposure for a long time (168 h), suggesting that reactive oxygen species (ROS) were generated under ATV exposure. Similarly, GST and SOD enzymatic activities significantly increased in most exposure treatments. Under ATV exposure, SIRT1 and SIRT2 displayed induction to some extent in most treatments, suggesting that SIRTs may affect PXR expression by regulating the acetylation levels of PXR. The investigation demonstrated that ATV exposure affected the expression of the Sirtuin/PXR signaling pathway, thus further interfered adaption of M. chulae to the environment. [ABSTRACT FROM AUTHOR]

Allopregnanolone (3α-THP) has been one of the most studied progesterone metabolites for decades. 3α-THP and its synthetic analogs have been evaluated as therapeutic agents for pathologies such as anxiety and depression. Enzymes involved in the metabolism of 3α-THP are expressed in classical and nonclassical steroidogenic tissues. Additionally, due to its chemical structure, 3α-THP presents high affinity and agonist activity for nuclear and membrane receptors of neuroactive steroids and neurotransmitters, such as the Pregnane X Receptor (PXR), membrane progesterone receptors (mPR) and the ionotropic GABAA receptor, among others. 3α-THP has immunomodulator and antiapoptotic properties. It also induces cell proliferation and migration, all of which are critical processes involved in cancer progression. Recently the study of 3α-THP has indicated that low physiological concentrations of this metabolite induce the progression of several types of cancer, such as breast, ovarian, and glioblastoma, while high concentrations inhibit it. In this review, we explore current knowledge on the metabolism and mechanisms of action of 3α-THP in normal and tumor cells. [ABSTRACT FROM AUTHOR]

Tofacitinib, a Janus kinase 1 and 3 inhibitor, is used to treat rheumatoid arthritis. It is mainly metabolized by the cytochromes p450 (CYP) 3A1/2 and CYP2C11 in the liver. Chronic inflammation eventually leads to cirrhosis in patients with rheumatoid arthritis. Isosakuranetin (ISN), a component of Citrus aurantium L., has hepatoprotective effects in rats. This study was performed to determine the effects of ISN on the pharmacokinetics of tofacitinib in rats with N-dimethylnitrosamine-induced liver cirrhosis (LC). After intravenous administration of 10 mg/kg tofacitinib to control (CON), LC, and LC treated with ISN (LC-ISN) rats, the total area under the plasma concentration–time curves (AUC) from time zero to infinity increased by 158% in LC rats compared to those in CON rats; however, the AUC of LC-ISN rats decreased by 35.1% compared to that of LC rat. Similar patterns of AUC changes were observed in the LC and LC-ISN rats after oral administration of 20 mg/kg tofacitinib. These results can be attributed to decreased non-renal clearance (CLNR) and intestinal intrinsic clearance (CLint) in the LC rats and increased intestinal and hepatic CLint in the LC-ISN rats. Our findings imply that ISN treatment in LC rats restored the decrease in either CLNR or CLint, or both, through increased hepatic and intestinal expression of CYP3A1/2 and CYP2C11, which is regulated by the induction of pregnane X receptor (PXR) and constitutive androstane receptor (CAR). [ABSTRACT FROM AUTHOR]

Per- and poly-fluoroalkyl substances (PFAS) are a large class of fluorinated carbon chains that include legacy PFAS, such as perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorohexane sulfonate (PFHxS). These compounds induce adverse health effects, including hepatotoxicity. Potential alternatives to the legacy PFAS (HFPO-DA (GenX), HFPO4, HFPO-TA, F-53B, 6:2 FTSA, and 6:2 FTCA), as well as a byproduct of PFAS manufacturing (Nafion BP2), are increasingly being found in the environment. The potential hazards of these new alternatives are less well known. To better understand the diversity of molecular targets of the PFAS, we performed a comparative toxicogenomics analysis of the gene expression changes in the livers of mice exposed to these PFAS, and compared these to five activators of PPARα, a common target of many PFAS. Using hierarchical clustering, pathway analysis, and predictive biomarkers, we found that most of the alternative PFAS modulate molecular targets that overlap with legacy PFAS. Only three of the 11 PFAS tested did not appreciably activate PPARα (Nafion BP2, 6:2 FTSA, and 6:2 FTCA). Predictive biomarkers showed that most PFAS (PFHxS, PFOA, PFOS, PFNA, HFPO-TA, F-53B, HFPO4, Nafion BP2) activated CAR. PFNA, PFHxS, PFOA, PFOS, HFPO4, HFPO-TA, F-53B, Nafion BP2, and 6:2 FTSA suppressed STAT5b, activated NRF2, and activated SREBP. There was no apparent relationship between the length of the carbon chain, type of head group, or number of ether linkages and the transcriptomic changes. This work highlights the similarities in molecular targets between the legacy and alternative PFAS.

Pharmacological activation of the xenobiotic-sensing nuclear receptors pregnane X receptor (PXR) and constitutive androstane receptor (CAR) is well-known to increase drug metabolism and reduce inflammation. Little is known regarding their physiological functions on the gut microbiome. In this study, we discovered bivalent hormetic functions of PXR/CAR modulating the richness of the gut microbiome using genetically engineered mice. The absence of PXR or CAR increased microbial richness, and absence of both receptors synergistically increased microbial richness. PXR and CAR deficiency increased the pro-inflammatory bacteria Helicobacteraceae and Helicobacter. Deficiency in both PXR and CAR increased the relative abundance of Lactobacillus, which has bile salt hydrolase activity, corresponding to decreased primary taurine-conjugated bile acids (BAs) in feces, which may lead to higher internal burden of taurine and unconjugated BAs, both of which are linked to inflammation, oxidative stress, and cytotoxicity. The basal effect of PXR/CAR on the gut microbiome was distinct from pharmacological and toxicological activation of these receptors. Common PXR/CAR-targeted bacteria were identified, the majority of which were suppressed by these receptors. hPXR-TG mice had a distinct microbial profile as compared to wild-type mice. This study is the first to unveil the basal functions of PXR and CAR on the gut microbiome.

Abstract Background IL-35–producing Bregs and Treg cells critically regulate chronic illnesses worldwide via mechanisms related to disrupting the gut microbiota composition. However, whether the gut microbiota regulates these IL-35+ cells remains elusive. We herein investigated the regulatory effects of the gut microbiota on IL-35+ cells by using genetically modified mouse models of obesity. Results We first found that gut Reg4 promoted resistance to high-fat diet-induced obesity. Using 16S rRNA sequencing combined with LC-MS (liquid chromatography–mass spectrometry)/MS, we demonstrated that gut Reg4 associated with bacteria such as Lactobacillus promoted the generation of IL-35+ B cells through 3-idoleacetic acid (IAA) in the presence of LPS. HuREG4 IECtg mice fed a high-fat diet exhibited marked IL-35+ cell accumulation in not only their adipose tissues but also their colons, whereas decreased IL-35+ cell accumulation was observed in the adipose and colon tissues of Reg4 knockout (KO) mice. We also found that Reg4 mediated HFD-induced obesity resistance via IL-35. Lower levels of IAA were also detected in the peripheral blood of individuals with obesity compared with nonobese subjects. Mechanistically, IAA together with LPS mediated IL-35+ B cells through PXR and TLR4. KO of PXR or TLR4 impaired the generation of IL-35+ B cells. Conclusion Together, IAA and LPS induce the generation of IL-35+ B cells through PXR and TLR4. Video Abstract

The study aims to analyze the potential Herb-Drug Interactions (HDIs) of the chemical compound in Andrographis paniculate Burm. f. against Constitutive Androstane Receptor (CAR) and Pregnane X Receptor (PXR). The 1XVP and 1SKX obtained from the Protein Data Bank (PDB) were used as the targeted protein. The molecular docking analysis was done using the Molecular Operating Environment (MOE) and molecular dynamics simulation using Gromacs. The results of the docking analysis showed that 14-Deoxy-11,12-didehydroandrographolide had the strongest binding energy (1XVP-21.0998 Å) with the Arene-H binding type on Tyr326 and Andrographidine A had the strongest binding energy (1SKX-24.7363 Å) with the Arene-H binding type on Trp299. While Andrographolide is the major component, it also has a high affinity for the two PDB IDs (1XVP-17.4044 Å and 1SKX-21.8881 Å). Based on the RMSD value, the radius of gyration (Rg), and MM/PBSA on molecular dynamic simulations, it shows that the ligand and protein complex as a whole can bind strongly to amino acid residues at the active site. The complex also has sufficient stability and good affinity. Therefore, this study can predict the mechanism in HDIs, especially in CYP 450 expression through the activation pathways of CAR and PXR receptors.

The leguminosae of Sophora moorcroftiana (Benth.) Benth.ex Baker is a drought-resistant endemic Sophora shrub species from the Qinghai-Tibet Plateau, and its seeds have hepatoprotective effects. To study the effect of S. moorcroftiana seeds on liver injury and the molecular mechanism underlying the beneficial effects, liquid chromatography-mass spectrometry was used to detect the main active components in the ethanol extract of S. moorcroftiana seeds (SM). Male mice were divided into six groups (n = 8): normal control (NC), CCl4, SM (50, 100, 200 mg/kg), and dimethyl diphenyl bicarboxylate (150 mg/kg) groups. Mice were treated as indicated (once/day, orally) for 14 days, and CCl4 (2 mL/kg) was administered intraperitoneally. The serum and liver of mice were used for biochemical assays. To explore the underlying mechanism, HepG2 cells were treated with SM, stimulated with tert-butyl hydroperoxide (t-BHP, 50 μM), and analyzed by Western blotting. The major active compounds of SM were alkaloids including 22 compounds. Serum alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP) decreased in the SM (200 mg/kg) group. SM can activate the expression of pregnane X receptor (PXR) and downstream molecules cytochrome P4503A11 enzyme (CYP3A11), UDP glucuronosyltransferase 1 family polypeptide A 1 (UGT1A1), and inhibit the multidrug resistance protein 2 (MRP2). In addition, SM improved cell viability in t-BHP-induced HepG2 cells (64% to 83%) and decreased the activation of the mitogen-activated protein kinase (MAPK) pathway. The main compounds in SM were alkaloids. SM showed hepatoprotective effects possibly mediated by the suppression of oxidative stress through the MAPK pathway. [ABSTRACT FROM AUTHOR]

Paclitaxel (PTX) is one of the most efficient drugs for late-stage non-small cell lung cancer (NSCLC) patients. However, most patients gradually develop resistance to PTX with long-term treatments. The identification of new strategies to reverse PTX resistance in NSCLC is crucially important for the treatment. PTX is an agonist for the pregnane X receptor (PXR) which regulates PTX metabolism. Antagonizing PXR, therefore, may render the NSCLC more sensitive to the PTX treatment. In this study, we investigated the PXR antagonist SPA70 and its role in PTX treatment of NSCLC. In vitro, SPA70 and PTX synergistically inhibited cell growth, migration and invasion in both paclitaxel-sensitive and paclitaxel-resistant A549 and H460 lung cancer cells. Mechanistically, we found PTX and SPA70 cotreatment disassociated PXR from ABCB1 (MDR1, P-gp) promoter, thus inhibiting P-gp expression. Furthermore, the combination regimen synergistically enhanced the interaction between PXR and Tip60, which abrogated Tip60-mediated α-tubulin acetylation, leading to mitosis defect, S-phase arrest and necroptosis/apoptosis. Combination of PXT and SPA70 dramatically inhibited tumor growth in a paclitaxel-resistant A549/TR xenograft tumor model. Taken together, we showed that SPA70 reduced the paclitaxel resistance of NSCLC. The combination regimen of PTX and SPA70 could be potential novel candidates for the treatment of taxane-resistant lung cancer. [ABSTRACT FROM AUTHOR]

The pregnane X receptor (PXR, NR1I2) is a xenobiotic-activated transcription factor with high levels of expression in the liver. It not only plays a key role in drug metabolism and elimination, but also promotes tumor growth, drug resistance, and metabolic diseases. It has been proposed as a therapeutic target for type II diabetes, metabolic syndrome, and inflammatory bowel disease, and PXR antagonists have recently been considered as a therapy for colon cancer. There are currently no PXR antagonists that can be used in a clinical setting. Nevertheless, due to the large and complex ligand-binding pocket (LBP) of the PXR, it is challenging to discover PXR antagonists at the orthosteric site. Alternative ligand binding sites of the PXR have also been proposed and are currently being studied. Recently, the AF-2 allosteric binding site of the PXR has been identified, with several compounds modulating the site discovered. Herein, we aimed to summarize our current knowledge of allosteric modulation of the PXR as well as our attempt to unlock novel allosteric sites. We describe the novel binding function 3 (BF-3) site of PXR, which is also common for other nuclear receptors. In addition, we also mention a novel allosteric site III based on in silico prediction. The identified allosteric sites of the PXR provide new insights into the development of safe and efficient allosteric modulators of the PXR receptor. We therefore propose that novel PXR allosteric sites might be promising targets for treating chronic metabolic diseases and some cancers. [ABSTRACT FROM AUTHOR]

Introduction: Functional single-nucleotide polymorphisms (SNPs) in genes regulating cellular uptake, elimination, and metabolism of xenobiotics may potentially influence the outcome of chronic myeloid leukemia (CML) patients treated with BCR-ABL1 tyrosine kinase inhibitors (TKI). Dasatinib, a secondgeneration TKI, is a substrate of the ABC-superfamily xenobiotic transporters ABCB1 (MDR1, Pg-P) and ABCG2 (BCRP). Pregnane X receptor (PXR, NR1I2) and constitutive androstane receptor (CAR, NR1I3) are involved in the control of expression of ABCB1 and ABCG2. Aim of the study: In this study, we assessed the impact of inherited variants in ABCB1, ABCG2, PXR, and CAR genes on dasatinib efficacy and toxicity in CML. Materials and Methods: Sixty-one tagging SNPs in ABCB1, ABCG2, PXR, and CAR genes were analyzed by real-time quantitative PCR with specific probes in 86 CML patients who failed imatinib therapy. Results: We found the associations between SNPs rs7787082 (ABCB1, OR = 0.2; 95% CI = 0.06-0.66, p = 0.008), rs12505410 (ABCG2, OR = 3.82; 95% CI = 1.38-10.55; p = 0.010), and rs3114018 (ABCG2, OR = 0.24; 95% CI = 0.08-0.71; p = 0.010) and the probability of achieving CCyR. Furthermore, progression-free survival (PFS) was significantly influenced by SNPs rs3732357 (HR = 0.2, 95% CI = 0.26-0.70; p = 0.001), rs3732360 (HR = 0.59; 95% CI = 0.38-0.93; p = 0.020), rs11917714 (HR = 0.58; 95% CI = 0.36-0.92; p = 0.020), and rs3732359 (HR = 0.57; 95% CI = 0.36-0.91; p = 0.024) in PXR; rs2307418 (HR = 2.02; 95% CI = 1.19- 3.43; p = 0.048) in CAR; and rs2235023 (HR = 2.49; 95% CI = 1.13-5.50; p = 0.011) and rs22114102 (HR = 1.90; 95% CI = 1.00-3.63; p = 0.028) in ABCB1. Moreover, overall survival (OS) was impacted by rs3842 (HR = 1.84; 95% CI = 1.01-3.33; p = 0.012) and rs2235023 (HR = 2.28; 95% CI = 1.03 = 5.02; p = 0.027) in ABCB1, rs11265571 (HR = 1.59; 95% CI = 0.82-3.08; p = 0.037) and rs2307418 (HR = 73.68; 95% CI = 4.47-1215.31; p = 0.003) in CAR, and rs3732360 (HR = 0.64; 95% CI = 0.40 = 1.04; p = 0.049) in PXR. Taking into account the influence of the tested SNPs on treatment toxicity, we found a significant relationship between allele G of polymorphism in the ABCB1 rs7787082 (OR = 4.46; 95% CI = 1.38- 14.39 p = 0.012) and hematological complications assuming the codominant gene inheritance model as well as a significant correlation between the presence of minor allele (G) of SNP rs2725256 in the ABCG2 gene (OR = 4.71; 95% CI = 1.20-18.47; p = 0.026) and the occurrence of non-hematological complications assuming a recessive gene inheritance model. Conclusion: Our data suggest that inherited variants in the genes encoding for proteins involved in the transport of xenobiotics may modify the toxicity and efficacy of dasatinib therapy in CML patients. [ABSTRACT FROM AUTHOR]

Pregnane X receptor (PXR, NR1I2), a prototypical member of the nuclear receptor superfamily, has been implicated in various processes including metabolism, immune response, and inflammation. The immune system is made up of many interdependent parts, including lymphoid organs, cells, and cytokines, which play important roles in identifying, repelling, and eliminating pathogens and other foreign chemicals. An impaired immune system could contribute to various physical dysfunction, including severe infections, allergic diseases, autoimmune disorders, and other inflammatory diseases. Recent studies revealed the involvement of PXR in the pathogenesis of immune disorders and inflammatory responses. Thus, the aim of this work is to review and discuss the advances in research associated with PXR on immunity and inflammatory diseases and to provide insights into the development of therapeutic interventions of immune disorders and inflammatory diseases by targeting PXR. [ABSTRACT FROM AUTHOR]

The nuclear receptors PXR, CAR, and FXR are activated by various ligands and function as transcription factors to control the expression of genes that regulate the synthesis and metabolism of androstenone and skatole. These compounds are produced in entire male pigs and accumulate in the fat to cause the development of a meat quality issue known as boar taint. The extent of this accumulation is influenced by the synthesis and hepatic clearance of androstenone and skatole. For this reason, PXR, CAR, and FXR-mediated signaling pathways have garnered interest as potential targets for specialized treatments designed to reduce the development of boar taint. Recent research has also identified several metabolites produced by gut microbes that act as ligands for these nuclear receptors (e.g., tryptophan metabolites, short-chain fatty acids, bile acids); however, the connection between the gut microbiome and boar taint development is not clear. In this review, we describe the nuclear receptor signaling pathways that regulate the synthesis and metabolism of boar taint compounds and outline the genes involved. We also discuss several microbial-derived metabolites and dietary additives that are known or suspected nuclear receptor ligands and suggest how these compounds could be used to develop novel treatments for boar taint. [ABSTRACT FROM AUTHOR]

Triple-negative breast cancer (TNBC) is currently the only subtype lacking efficient targeted therapies. Taxol is the primary chemotherapeutic agent for TNBC. However, Taxol resistance often develops in the treatment of TNBC patients, which importantly contributes to high mortality and poor prognosis in TNBC patients. Recent preclinical studies have shown that the inhibition of Notch pathway by γ-secretase inhibitors can slow down the progression of TNBC. Our studies in bioinformatic analysis of breast cancer patients and TNBC/Taxol cells in vitro showed that there was high correlation between the activation of Notch pathway and Taxol resistance in TNBC. Increased γ-secretase activity (by the overexpression of catalytic core PSEN-1) significantly reduced Taxol sensitivity of TNBC cells, and enhanced biological characteristics of malignancy in vitro, and tumour growth in vivo. Mechanistically, increased γ-secretase activity led to the accumulation of NICD in the nucleus, promoting the interaction between NICD and PXR to activate PXR, which triggered the transcription of PXR downstream associated drug resistance genes. Furthermore, we showed that pharmacological inhibition of γ-secretase with γ-secretase inhibitors (Nirogacestat and DAPT) can reverse Taxol resistance in vivo and in vitro. Our results for the first time demonstrate that the activation of γ -secretase/NCD-PXR/Notch pathway is one of important mechanisms to cause Taxol resistance in TNBC, and the blockades of this pathway may represent a new therapeutic strategy for overcoming Taxol resistance in TNBC., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The pregnane X receptor (PXR) is a key regulator of metabolism, but the mechanisms underlying its antagonism remain unclear. Garcia-Maldonado et al. reported potent new antagonists and their co-crystal structures, revealing molecular determinants of PXR antagonism and paving the way for developing antagonists as therapeutics and preventing undesirable PXR activation., Competing Interests: Declaration of interests The authors declare no competing interests. P.P. is an advisor in Lipidera Therapeutics company., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Astilbin (ATB), a natural dihydroflavonol compound, exists in many plants, processed and functional foods. ATB has multiple pharmacological effects, such as antioxidant, lipid-lowering, and hepatoprotective. However, its anti-hepatic fibrosis and mechanisms remain unclearly elucidated., Purpose: This study explored the effect of ATB against the hepatic fibrosis and its regulation of hepatic microenvironment by regulating hepatic stellate cells-macrophage crosstalk., Method: Thioacetamide (TAA) was intraperitoneal injected to establish hepatic fibrosis mice, and treated with ATB or curcumin by gavage, respectively. Hepatic stellate cells (HSCs) were stimulated with TGF-β or conditioned medium (CM) from LPS-induced THP-1, then cultured with ATB, PXR agonist or antagonist., Results: In TAA-induced mice, ATB improved histopathological changes, serum transaminases increase; alleviated extracellular matrix (ECM) deposition, epithelial-mesenchymal transformation (EMT), inflammatory infiltration, PTEN induced kinase 1 (PINK1)/Parkin-mediated mitophagy and activated pregnane X receptor (PXR) expression. In vitro, ATB significantly reduced ECM, inflammatory cytokines release, mitophagy, EMT, and activated PXR expression. ATB could increase PXR and decrease PINK1/Parkin, functioning as a PXR agonist. PXR deficiency in LX-2 could degrade the regulation of ATB on ECM, inflammation, EMT, and mitophagy. CM from LPS-induced THP-1 activated LX-2 and resulted in PXR decreasing, while ATB could regulate the crosstalk between HSCs and macrophages. Deficiency of PXR, whether in LX-2 or in macrophages, all weakened the inhibitory effect of ATB on α-SMA, EMT, inflammatory cytokines, and PINK1/Parkin signaling., Conclusion: ATB ameliorated hepatic fibrosis by inhibiting HSCs activation, inflammation and EMT through PXR-mediated PINK1/Parkin signaling. Especially, ATB targeted the hepatic microenvironment between hepatic stellate cells and macrophages, which might be a promising strategy for the treatment of hepatic fibrosis., Competing Interests: Declaration of competing interest The authors have declared no conflict of interest., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

Plasminogen activator inhibitor 1 (PAI-1) is a crucial serine protease inhibitor that prevents plasminogen activation by inhibiting tissue- and urokinase-type plasminogen activators (tPA, uPA). PAI-1 is well-known for its role in modulating hemocoagulation or extracellular matrix formation by inhibiting plasmin or matrix metalloproteinases, respectively. PAI-1 is induced by pro-inflammatory cytokines across various tissues, yet its regulation by ligand-activated transcription factors is partly disregarded. Therefore, we have attempted to summarize the current knowledge on the transcriptional regulation of PAI-1 expression by the most relevant xenobiotic and endocrine receptors implicated in modulating PAI-1 levels. This review aims to contribute to the understanding of the specific, often tissue-dependent regulation of PAI-1 and provide insights into the modulation of PAI-1 levels beyond its direct inhibition., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)

Hodgkin's lymphoma (HL) is the most common cancer in adolescents and young adults. A family history of HL increases the risk of developing HL in other family members. Identification of genetic predisposition variants in HL is important for understanding disease aetiology, prognosis, and response to treatment. Aberrant activation of the NF-κB pathway is a hallmark feature of HL, contributing to the survival and proliferation of the malignant cells' characteristic of HL. The family with multiple consanguineous marriages with siblings of diagnosed HL was examined by whole-exome sequencing. We found a germline homozygous variation in the PXR ligand binding domain (NM&#95;003889.3:c.811G>A, p.(Asp271Asn)), which was classified as pathogenic by prediction tools and segregated in HL cases. Increased PXR expression was found in homozygous variant carriers compared to heterozygous carriers by quantitative real time PCR (qRT-PCR) and immunofluorescence staining of patients' formalin-fixed paraffin-embedded tissues showed upregulation of PXR, particularly in Hodgkin Reed/Sternberg (HRS) cells. Patients with homozygous PXR variant showed significantly high expression compared to PXR wild-type HL, heterozygous and controls (p = 0.0001, p = 0.0004 and p = 0.0001, respectively). PXR homozygous HRS cells had significantly higher PXR expression compared to PXR wild-type HRS cells (p < 0.0001, 3.27-fold change). Albeit PXR's prominent expression in cytoplasm of HRS cells, homozygous PXR HRS cells showed increased PXR expression in nucleus (p < 0.001). PXR is a member of the nuclear receptor superfamily and previous studies have demonstrated a pleiotropic effect of PXR on malignant transformation. Expression analysis showed that cell proliferation, apoptosis and inflammation related genes were deregulated, in homozygous PXR HL cases. This study provided clinical evidence to previously reported Sxr -/- mice model that develop multifocal lymphomas, had an aberrantly increased NF-κB expression and consistent inflammation. Further functional studies are needed to elucidate the exact mechanisms of action of PXR in HL pathogenesis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

IntroductionFunctional single-nucleotide polymorphisms (SNPs) in genes regulating cellular uptake, elimination, and metabolism of xenobiotics may potentially influence the outcome of chronic myeloid leukemia (CML) patients treated with BCR-ABL1 tyrosine kinase inhibitors (TKI). Dasatinib, a second-generation TKI, is a substrate of the ABC-superfamily xenobiotic transporters ABCB1 (MDR1, Pg-P) and ABCG2 (BCRP). Pregnane X receptor (PXR, NR1I2) and constitutive androstane receptor (CAR, NR1I3) are involved in the control of expression of ABCB1 and ABCG2.Aim of the studyIn this study, we assessed the impact of inherited variants in ABCB1, ABCG2, PXR, and CAR genes on dasatinib efficacy and toxicity in CML.Materials and methodsSixty-one tagging SNPs in ABCB1, ABCG2, PXR, and CAR genes were analyzed by real-time quantitative PCR with specific probes in 86 CML patients who failed imatinib therapy.ResultsWe found the associations between SNPs rs7787082 (ABCB1, OR = 0.2; 95% CI = 0.06-0.66, p = 0.008), rs12505410 (ABCG2, OR = 3.82; 95% CI = 1.38-10.55; p = 0.010), and rs3114018 (ABCG2, OR = 0.24; 95% CI = 0.08-0.71; p = 0.010) and the probability of achieving CCyR. Furthermore, progression-free survival (PFS) was significantly influenced by SNPs rs3732357 (HR = 0.2, 95% CI = 0.26-0.70; p = 0.001), rs3732360 (HR = 0.59; 95% CI = 0.38-0.93; p = 0.020), rs11917714 (HR = 0.58; 95% CI = 0.36-0.92; p = 0.020), and rs3732359 (HR = 0.57; 95% CI = 0.36-0.91; p = 0.024) in PXR; rs2307418 (HR = 2.02; 95% CI = 1.19-3.43; p = 0.048) in CAR; and rs2235023 (HR = 2.49; 95% CI = 1.13-5.50; p = 0.011) and rs22114102 (HR = 1.90; 95% CI = 1.00-3.63; p = 0.028) in ABCB1. Moreover, overall survival (OS) was impacted by rs3842 (HR = 1.84; 95% CI = 1.01-3.33; p = 0.012) and rs2235023 (HR = 2.28; 95% CI = 1.03 = 5.02; p = 0.027) in ABCB1, rs11265571 (HR = 1.59; 95% CI = 0.82-3.08; p = 0.037) and rs2307418 (HR = 73.68; 95% CI = 4.47-1215.31; p = 0.003) in CAR, and rs3732360 (HR = 0.64; 95% CI = 0.40 = 1.04; p = 0.049) in PXR. Taking into account the influence of the tested SNPs on treatment toxicity, we found a significant relationship between allele G of polymorphism in the ABCB1 rs7787082 (OR = 4.46; 95% CI = 1.38-14.39 p = 0.012) and hematological complications assuming the codominant gene inheritance model as well as a significant correlation between the presence of minor allele (G) of SNP rs2725256 in the ABCG2 gene (OR = 4.71; 95% CI = 1.20-18.47; p = 0.026) and the occurrence of non-hematological complications assuming a recessive gene inheritance model.ConclusionOur data suggest that inherited variants in the genes encoding for proteins involved in the transport of xenobiotics may modify the toxicity and efficacy of dasatinib therapy in CML patients.

Of the patients infected with coronavirus disease 2019 (COVID-19), approximately 14-53% developed liver injury resulting in poor outcomes. Drug-induced liver injury (DILI) is the primary cause of liver injury in COVID-19 patients. In this study, we elucidated liver injury mechanism induced by drugs of pharmacologic treatments against SARS-CoV-2 (DPTS) using bioinformatics and systems biology. Totally, 1209 genes directly related to 216 DPTS (DPTSGs) were genes encoding pharmacokinetics and therapeutic targets of DPTS and enriched in the pathways related to drug metabolism of CYP450s, pregnane X receptor (PXR), and COVID-19 adverse outcome. A network, constructed by 110 candidate targets which were the shared part of DPTSGs and 445 DILI targets, identified 49 key targets and four Molecular Complex Detection clusters. Enrichment results revealed that the 4 clusters were related to inflammatory responses, CYP450s regulated by PXR, NRF2-regualted oxidative stress, and HLA-related adaptive immunity respectively. In cluster 1, IL6, IL1B, TNF, and CCL2 of the top ten key targets were enriched in COVID-19 adverse outcomes pathway, indicating the exacerbation of COVID-19 inflammation on DILI. PXR-CYP3A4 expression of cluster 2 caused DILI through inflammation-drug interaction and drug-drug interactions among pharmaco-immunomodulatory agents, including tocilizumab, glucocorticoids (dexamethasone, methylprednisolone, and hydrocortisone), and ritonavir. NRF2 of cluster 3 and HLA targets of cluster four promoted DILI, being related to ritonavir/glucocorticoids and clavulanate/vancomycin. This study showed the pivotal role of PXR associated with inflammation-drug and drug-drug interactions on DILI and highlighted the cautious clinical decision-making for pharmacotherapy to avoid DILI in the treatment of COVID-19 patients. [ABSTRACT FROM AUTHOR]

The pregnane X receptor (PXR) is a master xenobiotic-sensing receptor in response to toxic byproducts, as well as a key regulator in intermediary lipid metabolism. Therefore, the present study was conducted to investigate the potential role of PXR in mediating the lipid dysregulation and xenobiotic responses under Cu-induced stress in largemouth bass (Micropterus salmoides). Four groups of largemouth bass (52.66 ± 0.03 g) were treated with control, Cu waterborne (9.44 mmol/L), Cu+RIF (Rifampicin, 100 mg/kg, PXR activator), and Cu+KET (Ketoconazole, 20 mg/kg, PXR inhibitor) for 48 h. Results showed that Cu exposure significantly elevated the plasma stress indicators and triggered antioxidant systems to counteract Cu-induced oxidative stress. Acute Cu exposure caused liver steatosis, as indicated by the significantly higher levels of plasma triglycerides (TG), lipid droplets, and mRNA levels of lipogenesis genes in the liver. Liver injuries were detected, as shown by hepatocyte vacuolization and severe apoptotic signals after Cu exposure. Importantly, Cu exposure significantly stimulated mRNA levels of PXR, suggesting the response of this regulator in the xenobiotic response. The pharmacological intervention of PXR by the agonist and antagonist significantly altered hepatic mRNA levels of PXR, implying that RIF and KET were effective agents of PXR in largemouth bass. Administration of RIF significantly exacerbated liver steatosis, and such alterations were dependent on the regulations on pparg and cd36 rather than srebp1 signaling, which suggested that PXR-PPARγ might be another pathway for Cu-induced lipid deposition in fish. Whereas, KET administration showed reverse effects on lipid metabolism as indicated by the lower hepatic TG levels, suppressed mRNA levels of pparg and cd36. Activation of PXR stimulated autophagy and inhibited apoptosis, leading to lower hepatic vacuolization; while inhibition of PXR showed higher apoptotic signals, inhibition of autophagic genes and stimulation of apoptotic genes. Taken together, PXR played a cytoprotective role in Cu-induced hepatotoxicity through regulations on autophagy and apoptosis. Overall, our data has demonstrated for the first time on the dual roles of PXR as a co-regulator in mediating xenobiotic responses and lipid metabolism in fish, which implying the potential of PXR as a therapy target for xenobiotics-induced lipid dysregulation and hepatotoxicity. [ABSTRACT FROM AUTHOR]

Electronic-cigarette smoke (eCS) has been shown to cause a degree of oxidative stress and inflammatory damage in lung tissue. The aim of this study was to evaluate the repair mechanism of Eurotium cristatum fermented loose dark tea (ECT) and Eurotium cristatum particle metabolites (ECP) sifted from ECT after eCS-induced injury in mice. Sixty C57BL/6 mice were randomly divided into a blank control group, an eCS model group, an eCS + 600 mg/kg ECP treatment group, an eCS + 600 mg/kg ECT treatment group, an eCS + 600 mg/kg ECP prevention group, and an eCS + 600 mg/kg ECT prevention group. The results show that ECP and ECT significantly reduced the eCS-induced oxidative stress and inflammation and improved histopathological changes in the lungs in mice with eCS-induced liver injury. Western blot analysis further revealed that ECP and ECT significantly inhibited the eCS-induced upregulation of the phosphorylation levels of the extracellular Regulated protein Kinases (ERK), c-Jun N-terminal kinase (JNK) and p38mitogen-activated protein kinases (p38MAPK) proteins, and significantly increased the eCS-induced downregulation of the expression levels of the pregnane X receptor (PXR) and aryl hydrocarbon receptor (AhR) proteins. Conclusively, these findings show that ECP and ECT have a significant repairing effect on the damage caused by eCS exposure through the MAPK and PXR/AhR signaling pathways; ECT has a better effect on preventing eCS-induced injury and is suitable as a daily healthcare drink; ECP has a better therapeutic effect after eCS-induced injury, and might be a potential therapeutic candidate for the treatment of eCS-induced injury. [ABSTRACT FROM AUTHOR]

Myocardial infarction (MI) has emerged as the primary cause of global mortality. Managing blood sugar levels could play a vital role in the treatment of MI. Dapagliflozin (DPG), a commonly used hypoglycemic drug, has demonstrated efficacy in treating heart failure. However, the impact of DPG on MI remains unclear. We aimed to investigate the effects and mechanisms of DPG in relation to MI. DPG administration alleviated MI-induced cardiac dysfunction and myocardial fibrosis. We also found that DPG administration mitigated cardiomyocyte apoptosis through TUNEL staining. CD31 and α-Sma staining revealed that DPG promotes post-MI angiogenesis in mice. In vitro, using scratch assays, transwell assays, and tube formation assays, we discovered that DPG enhanced HUVEC proliferation capacity. Mechanistically, DPG promoted the expression of extracellular matrix genes and mitochondrial function-related genes. Additionally, molecular docking identified the interaction between DPG and PXR, which activated PXR and recruited it to the promoters of Pgam2 and Tcap, promoting their expressions, thus facilitating angiogenesis and post-MI heart repair. DPG promotes angiogenesis by activating PXR, thereby alleviating cardiac dysfunction and fibrosis after myocardial infarction. This study provides new strategies and targets for the treatment of ischemic disease. [Display omitted] • Dapagliflozin exerts cardioprotective effects in myocardial infarction. • Dapagliflozin promotes endothelial cell proliferation and migration. • Cardioprotective effects of Dapagliflozin is via interacting and activating PXR. • PXR upregulates genes related to ECM and mitochondrial function to repair infarcted hearts. [ABSTRACT FROM AUTHOR]

• The CYP450 content in zebrafish GI tract remained unaffected after BP-2 exposure. • CYP3A activity significantly increased with higher BP-2 concentrations after 15 days. • In silico suggests BP-2 may interact with PXR, inducing toxicity via PXR pathways. • Docking studies suggest that BP-2 could bind the ERα LBD. Benzophenone-2 (2,2′, 4,4′- Tetrahydroxybenzophenone; BP-2) is widely used as a sunscreen in Personal and Care Products (PCPs) for protection against ultraviolet (UV) radiation. The effects of BP-2 on random-sex adult zebrafish (Danio rerio) cytochrome P450 (CYP450) were studied. The main goal was to investigate the detoxification mechanisms underlying the adverse consequences of exposure to xenobiotic chemicals such as BP-2. Total protein content, CYP450 content, and erythromycin N-demethylase (ERND) activity were evaluated as indicators of protein CYP3A expression. Five sets of pooled random-sex adult zebrafish were exposed to 0.0, 0.1, 5.0, and 10.0 mg/L of BP-2 to evaluate their acute and chronic toxicity (4 and 15 days, respectively). ERND activity was significantly increased in the chronic toxicity group compared to that in the control group, whereas CYP450 remained unchanged. The results suggest a sufficiently fast catalytic process that does not alter the total CYP450 content. It implies a mediation of CYP450 3A induction by BP-2 and the pregnane X receptor ligand-binding domain (PXR LBD) interaction. Ligand-protein interactions were confirmed via in silico docking with AutoDock Vina. Further computational studies indicate BP-2 potential binding affinity for the Estrogen receptor alpha ligand binding domain (ERα LBD). These results suggest that CYPs effects may result in significant toxicity in the zebrafish. Our study highlights the importance of studying biomarkers in aquatic organisms to assess xenobiotic exposure and the potential toxicity of UV filters to humans. [Display omitted] [ABSTRACT FROM AUTHOR]

Bile acids are soluble derivatives of cholesterol produced in the liver that subsequently undergo bacterial transformation yielding a diverse array of metabolites. The bulk of bile acid synthesis takes place in the liver yielding primary bile acids; however, other tissues have also the capacity to generate bile acids (e.g. ovaries). Hepatic bile acids are then transported to bile and are subsequently released into the intestines. In the large intestine, a fraction of primary bile acids is converted to secondary bile acids by gut bacteria. The majority of the intestinal bile acids undergo reuptake and return to the liver. A small fraction of secondary and primary bile acids remains in the circulation and exert receptor-mediated and pure chemical effects (e.g. acidic bile in oesophageal cancer) on cancer cells. In this review, we assess how changes to bile acid biosynthesis, bile acid flux and local bile acid concentration modulate the behavior of different cancers. Here, we present in-depth the involvement of bile acids in oesophageal, gastric, hepatocellular, pancreatic, colorectal, breast, prostate, ovarian cancer. Previous studies often used bile acids in supraphysiological concentration, sometimes in concentrations 1000 times higher than the highest reported tissue or serum concentrations likely eliciting unspecific effects, a practice that we advocate against in this review. Furthermore, we show that, although bile acids were classically considered as pro-carcinogenic agents (e.g. oesophageal cancer), the dogma that switch, as lower concentrations of bile acids that correspond to their serum or tissue reference concentration possess anticancer activity in a subset of cancers. Differences in the response of cancers to bile acids lie in the differential expression of bile acid receptors between cancers (e.g. FXR vs. TGR5). UDCA, a bile acid that is sold as a generic medication against cholestasis or biliary surge, and its conjugates were identified with almost purely anticancer features suggesting a possibility for drug repurposing. Taken together, bile acids were considered as tumor inducers or tumor promoter molecules; nevertheless, in certain cancers, like breast cancer, bile acids in their reference concentrations may act as tumor suppressors suggesting a Janus-faced nature of bile acids in carcinogenesis. [ABSTRACT FROM AUTHOR]

Low response rate to radiotherapy remains a problem for liver and colorectal cancer patients due to inappropriate DNA damage response in tumors. Here, we report that pregnane X receptor (PXR) contributes to irradiation (IR) resistance by promoting activating transcription factor 3 (ATF3)-mediated ataxia-telangiectasia-mutated protein (ATM) activation. PXR stabilized ATF3 protein by blocking its ubiquitination. PXR–ATF3 interaction is required for regulating ATF3, as one mutant of lysine (K) 42R of ATF3 lost binding with PXR and abolished PXR-reduced ubiquitination of ATF3. On the other hand, threonine (T) 432A of PXR lost binding with ATF3 and further compromised ATM activation. Moreover, the PXR–ATF3 interaction increases ATF3 stabilization through disrupting ATF3–murine double minute 2 (MDM2) interaction and negatively regulating MDM2 protein expression. PXR enhanced MDM2 auto-ubiquitination and shortened its half-life, therefore compromising the MDM2-mediated degradation of ATF3 protein. Structurally, both ATF3 and PXR bind to the RING domain of MDM2, and on the other hand, MDM2 binds with PXR on the DNA-binding domain (DBD), which contains zinc finger sequence. Zinc finger sequence is well known for nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ) playing E3 ligase activity to degrade nuclear factor κB (NFκB)/p65. However, whether zinc-RING sequence grants E3 ligase activity to PXR remains elusive. Taken together, these results provide a novel mechanism that PXR contributes to IR resistance by promoting ATF3-mediated ATM activation through stabilization of ATF3. Our result suggests that targeting PXR may sensitize liver and colon cancer cells to IR therapy. [ABSTRACT FROM AUTHOR]

Objective: To explore the mechanism underlying the effect of Panax notoginseng saponins (PNS) on the pharmacokinetics of nifedipine (NF) in rats. Materials and Methods: Twenty-four rats were randomly divided into blank (BL) group, PNS group, NF group, and PNS + NF group, with six rats in each group. Noncompartmental analysis and t-test were carried out to determine the difference between the pharmacokinetic parameters of NF in different groups. CYP3A4 enzyme activity was calculated using the probe drug method. The mRNA and protein contents of CYP3A4, nuclear receptor CAR, and PXR in rat liver were quantitatively analyzed by qRT-PCR and Western blot. Results: After the rats were treated with the combination of PNS and NF, the plasma concentration, half-life, peak time, and area under the concentration-time curve of NF increased, whereas the clearance rate decreased. The inhibitory effect on CYP3A4 enzyme activity was in the following order: PNS + NF group (strongest) > PNS group > NF group, and BL group (weakest). Similar changes were observed for the inhibitory effect on CYP3A4, CAR, and PXR mRNA and protein content, and the order was as follows: PNS + NF group (weakest) < PNS group < NF group, and BL group (strongest). Conclusion: In combination with NF, PNS may inhibit the mRNA and protein expression of nuclear receptor CAR and PXR and the activity of CYP3A4 enzyme, slowing down the pharmacokinetics of NF in rats, increasing its blood concentration, and enhancing the therapeutic effect of NF.

Low response rate to radiotherapy remains a problem for liver and colorectal cancer patients due to inappropriate DNA damage response in tumors. Here, we report that pregnane X receptor (PXR) contributes to irradiation (IR) resistance by promoting activating transcription factor 3 (ATF3)-mediated ataxia-telangiectasia-mutated protein (ATM) activation. PXR stabilized ATF3 protein by blocking its ubiquitination. PXR–ATF3 interaction is required for regulating ATF3, as one mutant of lysine (K) 42R of ATF3 lost binding with PXR and abolished PXR-reduced ubiquitination of ATF3. On the other hand, threonine (T) 432A of PXR lost binding with ATF3 and further compromised ATM activation. Moreover, the PXR–ATF3 interaction increases ATF3 stabilization through disrupting ATF3–murine double minute 2 (MDM2) interaction and negatively regulating MDM2 protein expression. PXR enhanced MDM2 auto-ubiquitination and shortened its half-life, therefore compromising the MDM2-mediated degradation of ATF3 protein. Structurally, both ATF3 and PXR bind to the RING domain of MDM2, and on the other hand, MDM2 binds with PXR on the DNA-binding domain (DBD), which contains zinc finger sequence. Zinc finger sequence is well known for nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ) playing E3 ligase activity to degrade nuclear factor κB (NFκB)/p65. However, whether zinc-RING sequence grants E3 ligase activity to PXR remains elusive. Taken together, these results provide a novel mechanism that PXR contributes to IR resistance by promoting ATF3-mediated ATM activation through stabilization of ATF3. Our result suggests that targeting PXR may sensitize liver and colon cancer cells to IR therapy.

Natural forms of vitamin E comprise four tocopherols and four tocotrienols. During the last twenty years, there have been breakthroughs in our understanding of vitamin E metabolism and biological activities of vitamin E metabolites. Research has established that tocopherols and tocotrienols are metabolized via ω-hydroxylase (CYP4F2)-initiated side chain oxidation to form 13′-hydroxychromanol and 13′-carobyxychromanol (13′-COOH). 13′-COOHs are further metabolized via β-oxidation and sulfation to intermediate carboxychromanols, terminal metabolite carboxyethyl-hydroxychroman (CEHC), and sulfated analogs. Animal and human studies show that γ-, δ-tocopherol and tocotrienols are more extensively metabolized than α-tocopherol (αT), as indicated by higher formation of CEHCs and 13′-COOHs from non-αT forms than those from αT. 13′-COOHs are shown to be inhibitors of cyclooxygenase-1/-2 and 5-lipoxygenase and much stronger than CEHCs for these activities. 13′-COOHs inhibit cancer cell growth, modulate cellular lipids and activate peroxisome proliferator-activated receptor-γ and pregnane X receptor. Consistent with mechanistic findings, αT-13′-COOH or δTE-13′-COOH, respective metabolites of αT or δ-tocotrienol, show anti-inflammatory and cancer-preventive effects, modulates the gut microbiota and prevents β-amyloid formation in mice. Therefore, 13′-COOHs are a new class of bioactive compounds with anti-inflammatory and anti-cancer activities and potentially capable of modulating lipid and drug metabolism. Based on the existing evidence, this author proposes that metabolites may contribute to disease-preventing effects of γ-, δ-tocopherol and tocotrienols. The role of metabolites in αT's actions may be somewhat limited considering controlled metabolism of αT because of its association with tocopherol-transport protein and less catabolism by CYP4F2 than other vitamin E forms. [Display omitted] • Vitamin E tocopherols and tocotrienols are metabolized by CYP4F2 to form metabolites including 13'-COOHs and CEHCs. • Gamma-, delta-tocopherols and tocotrienols are more extensively metabolized than alpha-tocopherol. • 13'-COOHs are inhibitors of cyclooxygenase-1/-2 and 5-lipoxygenase, inhibit cancer cell growth, and activate PPAR and PXR. • 13'-COOHs are capable of anti-inflammation, anti-cancer and modulating lipid and drug metabolism. • Metabolites may contribute to bioactivities of gamma- or delta-tocopherol and tocotrienols. [ABSTRACT FROM AUTHOR]

Pharmacological activation of the xenobiotic-sensing nuclear receptors pregnane X receptor (PXR) and constitutive androstane receptor (CAR) is well-known to increase drug metabolism and reduce inflammation. Little is known regarding their physiological functions on the gut microbiome. In this study, we discovered bivalent hormetic functions of PXR/CAR modulating the richness of the gut microbiome using genetically engineered mice. The absence of PXR or CAR increased microbial richness, and absence of both receptors synergistically increased microbial richness. PXR and CAR deficiency increased the pro-inflammatory bacteria Helicobacteraceae and Helicobacter. Deficiency in both PXR and CAR increased the relative abundance of Lactobacillus , which has bile salt hydrolase activity, corresponding to decreased primary taurine-conjugated bile acids (BAs) in feces, which may lead to higher internal burden of taurine and unconjugated BAs, both of which are linked to inflammation, oxidative stress, and cytotoxicity. The basal effect of PXR/CAR on the gut microbiome was distinct from pharmacological and toxicological activation of these receptors. Common PXR/CAR-targeted bacteria were identified, the majority of which were suppressed by these receptors. h PXR -TG mice had a distinct microbial profile as compared to wild-type mice. This study is the first to unveil the basal functions of PXR and CAR on the gut microbiome. Contrary to the reported anti-inflammatory functions of PXR and CAR following their pharmacological activations, basal PXR and CAR activities are necessary for immune surveillance through modulating the gut microbiota. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: IL-35–producing Bregs and Treg cells critically regulate chronic illnesses worldwide via mechanisms related to disrupting the gut microbiota composition. However, whether the gut microbiota regulates these IL-35+ cells remains elusive. We herein investigated the regulatory effects of the gut microbiota on IL-35+ cells by using genetically modified mouse models of obesity. Results: We first found that gut Reg4 promoted resistance to high-fat diet-induced obesity. Using 16S rRNA sequencing combined with LC-MS (liquid chromatography–mass spectrometry)/MS, we demonstrated that gut Reg4 associated with bacteria such as Lactobacillus promoted the generation of IL-35+ B cells through 3-idoleacetic acid (IAA) in the presence of LPS. HuREG4IECtg mice fed a high-fat diet exhibited marked IL-35+ cell accumulation in not only their adipose tissues but also their colons, whereas decreased IL-35+ cell accumulation was observed in the adipose and colon tissues of Reg4 knockout (KO) mice. We also found that Reg4 mediated HFD-induced obesity resistance via IL-35. Lower levels of IAA were also detected in the peripheral blood of individuals with obesity compared with nonobese subjects. Mechanistically, IAA together with LPS mediated IL-35+ B cells through PXR and TLR4. KO of PXR or TLR4 impaired the generation of IL-35+ B cells. Conclusion: Together, IAA and LPS induce the generation of IL-35+ B cells through PXR and TLR4. ESFDmA-1LKhrrc6QfnM_pP Video Abstract [ABSTRACT FROM AUTHOR]