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Marasco G, Cremon C, Barbaro MR, Bianco F, Stanghellini V, Barbara G. Microbiota modulation in disorders of gut-brain interaction. Dig Liver Dis 2024:S1590-8658(24)00742-4. [PMID: 38772789 DOI: 10.1016/j.dld.2024.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/03/2024] [Accepted: 05/07/2024] [Indexed: 05/23/2024]
Abstract
Disorders of gut-brain interaction (DGBI) are common chronic conditions characterized by persistent and recurring gastrointestinal symptoms triggered by several pathophysiological factors, including an altered gut microbiota. The most common DGBI are irritable bowel syndrome (IBS), functional constipation (FC) and functional dyspepsia (FD). Recently, a deep understanding of the role of the gut microbiota in these diseases was possible due to multi-omics methods capable to provide a comprehensive assessment. Most of the therapies recommended for these patients, can modulate the gut microbiota such as diet, prebiotics, probiotics and non-absorbable antibiotics, which were shown to be safe and effective. Since patients complain symptoms after food ingestion, diet represents the first line therapeutic approach. Avoiding dietary fat and fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, and increasing the number of soluble fibers represent the therapeutic choices for FD, IBS and FC respectively. Probiotics, as a category, have been employed with good results in all the abovementioned DGBI. Rifaximin has been shown to be useful in the context of bowel related disorders, although a recent trial showed positive results for FD. Fecal microbiota transplantation has been tested for IBS and FC with promising results. In this review, we will briefly summarize the current understanding on dysbiosis and discuss microbiota modulation strategies to treat patients with DGBI.
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Affiliation(s)
- Giovanni Marasco
- IRCCS Azienda Ospedaliero Universitaria di Bologna, Bologna, Italy; Department of Medical and Surgical Sciences, University of Bologna, Italy
| | - Cesare Cremon
- IRCCS Azienda Ospedaliero Universitaria di Bologna, Bologna, Italy; Department of Medical and Surgical Sciences, University of Bologna, Italy
| | | | - Francesca Bianco
- IRCCS Azienda Ospedaliero Universitaria di Bologna, Bologna, Italy
| | - Vincenzo Stanghellini
- IRCCS Azienda Ospedaliero Universitaria di Bologna, Bologna, Italy; Department of Medical and Surgical Sciences, University of Bologna, Italy
| | - Giovanni Barbara
- IRCCS Azienda Ospedaliero Universitaria di Bologna, Bologna, Italy; Department of Medical and Surgical Sciences, University of Bologna, Italy.
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2
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Staudinger JL, Mahroke A, Patel G, Dattel C, Reddy S. Pregnane X Receptor Signaling Pathway and Vitamin K: Molecular Mechanisms and Clinical Relevance in Human Health. Cells 2024; 13:681. [PMID: 38667296 PMCID: PMC11049418 DOI: 10.3390/cells13080681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 04/09/2024] [Accepted: 04/10/2024] [Indexed: 04/28/2024] Open
Abstract
This review explores the likely clinical impact of Pregnane X Receptor (PXR) activation by vitamin K on human health. PXR, initially recognized as a master regulator of xenobiotic metabolism in liver, emerges as a key regulator influencing intestinal homeostasis, inflammation, oxidative stress, and autophagy. The activation of PXR by vitamin K highlights its role as a potent endogenous and local agonist with diverse clinical implications. Recent research suggests that the vitamin K-mediated activation of PXR highlights this vitamin's potential in addressing pathophysiological conditions by promoting hepatic detoxification, fortifying gut barrier integrity, and controlling pro-inflammatory and apoptotic pathways. PXR activation by vitamin K provides an intricate association with cancer cell survival, particularly in colorectal and liver cancers, to provide new insights into potential novel therapeutic strategies. Understanding the clinical implications of PXR activation by vitamin K bridges molecular mechanisms with health outcomes, further offering personalized therapeutic approaches for complex diseases.
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Affiliation(s)
- Jeff L. Staudinger
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin Campus, 2901 St Johns Blvd, Joplin, MO 64804, USA (C.D.); (S.R.)
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Ren W, Wang Z, Guo H, Gou Y, Dai J, Zhou X, Sheng N. GenX analogs exposure induced greater hepatotoxicity than GenX mainly via activation of PPARα pathway while caused hepatomegaly in the absence of PPARα in female mice. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 344:123314. [PMID: 38218542 DOI: 10.1016/j.envpol.2024.123314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/27/2023] [Accepted: 01/04/2024] [Indexed: 01/15/2024]
Abstract
Despite their use as substitutes for perfluorooctanoic acid, the potential toxicities of hexafluoropropylene oxide dimer acid (HFPO-DA, commercial name: GenX) and its analogs (PFDMOHxA, PFDMO2HpA, and PFDMO2OA) remain poorly understood. To assess the hepatotoxicity of these chemicals on females, each chemical was orally administered to female C57BL/6 mice at the dosage of 0.5 mg/kg/d for 28 d. The contribution of peroxisome proliferator-activated receptors (PPARα and γ) and other nuclear receptors involving in these toxic effects of GenX and its analogs were identified by employing two PPAR knockout mice (PPARα-/- and PPARγΔHep) in this study. Results showed that the hepatotoxicity of these chemicals increased in the order of GenX < PFDMOHxA < PFDMO2HpA < PFDMO2OA. The increases of relative liver weight and liver injury markers were significantly much lower in PPARα-/- mice than in PPARα+/+ mice after GenX analog exposure, while no significant differences were observed between PPARγΔHep and its corresponding wildtype groups (PPARγF/F mice), indicating that GenX analog induce hepatotoxicity mainly via PPARα instead of PPARγ. The PPARα-dependent complement pathways were inhibited in PFDMO2HpA and PFDMO2OA exposed PPARα+/+ mice, which might be responsible for the observed liver inflammation. In PPARα-/- mice, hepatomegaly and increased liver lipid content were observed in PFDMO2HpA and PFDMO2OA treated groups. The activated pregnane X receptor (PXR) and constitutive activated receptor (CAR) pathways in the liver of PPARα-/- mice, which were highlighted by bioinformatics analysis, provided a reasonable explanation for hepatomegaly in the absence of PPARα. Our results indicate that GenX analogs could induce more serious hepatotoxicity than GenX whether there is a PPARα receptor or not. These chemicals, especially PFDMO2HpA and PFDMO2OA, may not be appropriate PFOA alternatives.
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Affiliation(s)
- Wanlan Ren
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China; State Environmental Protection Key Laboratory of Environmental Health Impact Assessment of Emerging Contaminants, School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhiru Wang
- State Environmental Protection Key Laboratory of Environmental Health Impact Assessment of Emerging Contaminants, School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Hua Guo
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China
| | - Yong Gou
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Jiayin Dai
- State Environmental Protection Key Laboratory of Environmental Health Impact Assessment of Emerging Contaminants, School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, 211166, China
| | - Xuming Zhou
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Nan Sheng
- State Environmental Protection Key Laboratory of Environmental Health Impact Assessment of Emerging Contaminants, School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
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Marasco G, Cremon C, Barbaro MR, Stanghellini V, Barbara G. Journal of Clinical Gastroenterology Lectureship Dubai 2022 : Management of Irritable Bowel Syndrome With Diarrhea. J Clin Gastroenterol 2024; 58:221-231. [PMID: 38227850 DOI: 10.1097/mcg.0000000000001964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 12/13/2023] [Indexed: 01/18/2024]
Abstract
Irritable bowel syndrome (IBS) with diarrhea (IBS-D) affects ~1% of the general population and is characterized by abdominal pain associated with diarrhea. IBS-D symptoms significantly impact the quality of life of patients. Major uncertainties remain regarding the optimal management of these patients. Several therapies have been investigated over the years for the treatment of IBS-D. In the initial management, commonly prescribed approaches with an effect on global IBS symptoms include a low Fermentable Oligo-, Di-, Mono-Saccharides and Polyols diet and probiotics, while antispasmodics are used for targeting abdominal pain and loperamide for diarrhea only. Additional therapeutic options for the relief of global IBS symptoms include rifaximin, 5-HT 3 antagonists, gut-directed psychological therapies, and eluxadoline, while tricyclic antidepressants can target abdominal pain and bile acid sequestrants diarrhea. Promising evidence exists for the use of mesalazine and fecal microbiota transplantation in IBS-D, although further evidence is needed for definitive conclusions regarding their efficacy.
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Affiliation(s)
- Giovanni Marasco
- IRCCS Azienda Ospedaliero Universitaria di Bologna
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Cesare Cremon
- IRCCS Azienda Ospedaliero Universitaria di Bologna
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | | | - Vincenzo Stanghellini
- IRCCS Azienda Ospedaliero Universitaria di Bologna
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Giovanni Barbara
- IRCCS Azienda Ospedaliero Universitaria di Bologna
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
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Florke Gee RR, Huber AD, Chen T. Regulation of PXR in drug metabolism: chemical and structural perspectives. Expert Opin Drug Metab Toxicol 2024; 20:9-23. [PMID: 38251638 PMCID: PMC10939797 DOI: 10.1080/17425255.2024.2309212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 01/19/2024] [Indexed: 01/23/2024]
Abstract
INTRODUCTION Pregnane X receptor (PXR) is a master xenobiotic sensor that transcriptionally controls drug metabolism and disposition pathways. PXR activation by pharmaceutical drugs, natural products, environmental toxins, etc. may decrease drug efficacy and increase drug-drug interactions and drug toxicity, indicating a therapeutic value for PXR antagonists. However, PXR's functions in physiological events, such as intestinal inflammation, indicate that PXR activators may be useful in certain disease contexts. AREAS COVERED We review the reported roles of PXR in various physiological and pathological processes including drug metabolism, cancer, inflammation, energy metabolism, and endobiotic homeostasis. We then highlight specific cellular and chemical routes that modulate PXR activity and discuss the functional consequences. Databases searched and inclusive dates: PubMed, 1 January 1980 to 10 January 2024. EXPERT OPINION Knowledge of PXR's drug metabolism function has helped drug developers produce small molecules without PXR-mediated metabolic liabilities, and further understanding of PXR's cellular functions may offer drug development opportunities in multiple disease settings.
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Affiliation(s)
- Rebecca R. Florke Gee
- Graduate School of Biomedical Sciences, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Andrew D. Huber
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
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DuPont HL. The potential for development of clinically relevant microbial resistance to rifaximin-α: a narrative review. Clin Microbiol Rev 2023; 36:e0003923. [PMID: 37971270 PMCID: PMC10732030 DOI: 10.1128/cmr.00039-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023] Open
Abstract
Rifaximin-α is a gut-targeted antibiotic indicated for numerous gastrointestinal and liver diseases. Its multifaceted mechanism of action goes beyond direct antimicrobial effects, including alterations in bacterial virulence, cytoprotective effects on host epithelial cells, improvement of impaired intestinal permeability, and reduction of proinflammatory cytokine expression via activation of the pregnane X receptor. Rifaximin-α is virtually non-absorbed, with low systemic drug levels contributing to its excellent safety profile. While there are high concentrations of drug in the colon, low water solubility leads to low colonic drug bioavailability, protecting the gut microbiome. Rifaximin-α appears to be more active in the bile-rich small bowel. Its important biologic effects are largely at sub-inhibitory concentration. Although in vitro testing of clinical isolates from rifaximin recipients has revealed rifaximin-resistant strains in some studies, the risk of emergent rifaximin-α resistance appears to be lower than for many other antibiotics. Rifaximin-α has been used for many years for traveler's diarrhea with no apparent increase in resistance levels in causative pathogens. Further, rifaximin-α retains its efficacy after long-term and recurrent usage in chronic gastrointestinal disorders. There are numerous reasons why the risk of microbial resistance to rifaximin-α may be lower than that for other agents, including low intestinal bioavailability in the aqueous colon, the mechanisms of action of rifaximin-α not requiring inhibitory concentrations of drug, and the low risk of cross transmission of rifaximin-α resistance between bacterial species. Reported emergence of vancomycin-resistant Enterococcus in liver-disease patients maintained on rifaximin needs to be actively studied. Further studies are required to assess the possible correlation between in vitro resistance and rifaximin-α efficacy.
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Affiliation(s)
- Herbert L. DuPont
- School of Public Health and McGovern Medical School, Baylor College of Medicine, Kelsey Research Foundation, University of Texas Health Science Center Houston, Houston, Texas, USA
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Vázquez-Gómez G, Petráš J, Dvořák Z, Vondráček J. Aryl hydrocarbon receptor (AhR) and pregnane X receptor (PXR) play both distinct and common roles in the regulation of colon homeostasis and intestinal carcinogenesis. Biochem Pharmacol 2023; 216:115797. [PMID: 37696457 DOI: 10.1016/j.bcp.2023.115797] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 09/13/2023]
Abstract
Both aryl hydrocarbon receptor (AhR) and pregnane X receptor (PXR) belong among key regulators of xenobiotic metabolism in the intestinal tissue. AhR in particular is activated by a wide range of environmental and dietary carcinogens. The data accumulated over the last two decades suggest that both of these transcriptional regulators play a much wider role in the maintenance of gut homeostasis, and that both transcription factors may affect processes linked with intestinal tumorigenesis. Intestinal epithelium is continuously exposed to a wide range of AhR, PXR and dual AhR/PXR ligands formed by intestinal microbiota or originating from diet. Current evidence suggests that specific ligands of both AhR and PXR can protect intestinal epithelium against inflammation and assist in the maintenance of epithelial barrier integrity. AhR, and to a lesser extent also PXR, have been shown to play a protective role against inflammation-induced colon cancer, or, in mouse models employing overactivation of Wnt/β-catenin signaling. In contrast, other evidence suggests that both receptors may contribute to modulation of transformed colon cell behavior, with a potential to promote cancer progression and/or chemoresistance. The review focuses on both overlapping and separate roles of the two receptors in these processes, and on possible implications of their activity within the context of intestinal tissue.
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Affiliation(s)
- Gerardo Vázquez-Gómez
- Department of Cytokinetics, Institute of Biophysics of the CAS, Královopolská 135, 61265 Brno, Czech Republic
| | - Jiří Petráš
- Department of Cytokinetics, Institute of Biophysics of the CAS, Královopolská 135, 61265 Brno, Czech Republic; Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - Zdeněk Dvořák
- Department of Cell Biology and Genetics, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Jan Vondráček
- Department of Cytokinetics, Institute of Biophysics of the CAS, Královopolská 135, 61265 Brno, Czech Republic.
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Rifaximin Improves Liver Functional Reserve by Regulating Systemic Inflammation. J Clin Med 2023; 12:jcm12062210. [PMID: 36983211 PMCID: PMC10054398 DOI: 10.3390/jcm12062210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/01/2023] [Accepted: 03/07/2023] [Indexed: 03/18/2023] Open
Abstract
Rifaximin, a non-absorbable antibiotic, has been demonstrated to be effective against hepatic encephalopathy (HE); however, its efficacy on liver functional reserve remains unknown. Here, we evaluated the efficacy of rifaximin on the liver functional reserve and serological inflammation-based markers in patients with cirrhosis. A retrospective study was conducted on patients who received rifaximin for more than three months at our hospital between November 2016 and October 2021. The recurrence and grade of HE, serological ammonia levels, Child–Pugh score (CPS), and serological inflammation-based markers such as the neutrophil–lymphocyte ratio (NLR), lymphocyte–monocyte ratio (LMR), platelet–lymphocyte ratio (PLR), C-reactive protein (CRP), and CRP to albumin ratio (CAR) were evaluated. The correlations between serological inflammation-based markers and liver functional reserve were evaluated. HE grades, serum ammonia levels, and inflammation-based markers significantly improved at three months compared with those at baseline. Patients with improved albumin levels showed significantly higher CRP improvement rates at both 3 and 12 months. Patients with an improvement in CAR at 3 months demonstrated a significant improvement in CPS at 12 months. Rifaximin improved the liver functional reserve in patients with cirrhosis. Improvements in inflammation-based markers, particularly CRP and albumin, may be involved in this process.
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de Wit K, Beuers U, Mukha A, Stigter ECA, Gulersonmez MC, Ramos Pittol JM, Middendorp S, Takkenberg RB, van Mil SWC. Rifaximin stimulates nitrogen detoxification by PXR-independent mechanisms in human small intestinal organoids. Liver Int 2023; 43:649-659. [PMID: 36463417 DOI: 10.1111/liv.15491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/30/2022] [Accepted: 12/02/2022] [Indexed: 02/13/2023]
Abstract
BACKGROUND AND AIMS Recurrent hepatic encephalopathy (HE) is characterized by hyperammonaemia in combination with neuropsychiatric abnormalities and is treated with lactulose and rifaximin. Rifaximin is a pregnane X receptor (PXR) agonist with low systemic and high intestinal bioavailability. The mechanisms by which it alleviates HE are unclear. We used human small intestinal (hSI) organoids to study whether rifaximin, via PXR activation, affects the epithelial biotransformation machinery, and to gain understanding of its low systemic availability. METHODS We generated PXR knockdown hSI organoids via lentiviral delivery of short hairpin RNAs. Organoids were cultured for 24 h with rifaximin or rifampicin. RNA-sequencing and metabolomics were performed to analyse gene expression and amino acid metabolism. Luminal rifaximin was quantified by photospectrometry. RESULTS Treatment of wild-type hSI organoids with rifaximin resulted in >twofold differential expression of 131 genes compared to DMSO. These effects were largely PXR independent and related to amino acid metabolism. Rifaximin decreased expression of glutaminase-2 and increased expression of asparagine synthetase and solute carrier 7A11, thereby increasing intracellular glutamine and asparagine concentrations, indicating active ammonia detoxification. Rifaximin was apically excreted into the lumen in an ATP binding cassette B1 (ABCB1)-dependent manner. CONCLUSIONS Rifaximin-after uptake into enterocytes-stimulates intracellular nitrogen detoxification by PXR-independent mechanisms. Active apical excretion of rifaximin by ABCB1 into the intestinal lumen explains its low systemic bioavailability. Our study implies that rifaximin, next to modulation of the microbiome, has direct effects on ammonia scavenging in the human small intestinal epithelium.
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Affiliation(s)
- Koos de Wit
- Department of Gastroenterology and Hepatology, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands
| | - Ulrich Beuers
- Department of Gastroenterology and Hepatology, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands
| | - Anna Mukha
- Center for Molecular Medicine, UMC Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Edwin C A Stigter
- Center for Molecular Medicine, UMC Utrecht, Utrecht University, Utrecht, The Netherlands
| | - M Can Gulersonmez
- Center for Molecular Medicine, UMC Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Jose M Ramos Pittol
- Center for Molecular Medicine, UMC Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Sabine Middendorp
- Division of Paediatric Gastroenterology, Wilhelmina Children's Hospital, UMC Utrecht, Utrecht University, Utrecht, The Netherlands.,Regenerative Medicine Center Utrecht, Utrecht, The Netherlands
| | - R Bart Takkenberg
- Department of Gastroenterology and Hepatology, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands
| | - Saskia W C van Mil
- Center for Molecular Medicine, UMC Utrecht, Utrecht University, Utrecht, The Netherlands
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Poudel S, Huber AD, Chen T. Regulation of Nuclear Receptors PXR and CAR by Small Molecules and Signal Crosstalk: Roles in Drug Metabolism and Beyond. Drug Metab Dispos 2023; 51:228-236. [PMID: 36116789 PMCID: PMC9900866 DOI: 10.1124/dmd.122.000858] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/16/2022] [Accepted: 08/29/2022] [Indexed: 01/31/2023] Open
Abstract
Pregnane X receptor (PXR) and constitutive androstane receptor (CAR) are ligand-activated transcription factors that regulate the expression of drug metabolizing enzymes and drug transporters. Since their discoveries, they have been studied as important factors for regulating processes related to drug efficacy, drug toxicity, and drug-drug interactions. However, their vast ligand-binding profiles extend into additional spaces, such as endogenously produced chemicals, microbiome metabolites, dietary compounds, and environmental pollutants. Therefore, PXR and CAR can respond to an enormous abundance of stimuli, resulting in significant shifts in metabolic programs and physiologic homeostasis. Naturally, PXR and CAR have been implicated in various diseases related to homeostatic perturbations, such as inflammatory bowel disorders, diabetes, and certain cancers. Recent findings have injected the field with new signaling mechanisms and tools to dissect the complex PXR and CAR biology and have strengthened the potential for future PXR and CAR modulators in the clinic. Here, we describe the historical and ongoing importance of PXR and CAR in drug metabolism pathways and how this history has evolved into new mechanisms that regulate and are regulated by these xenobiotic receptors, with a specific focus on small molecule ligands. To effectively convey the impact of newly emerging research, we have arranged five diverse and representative key recent advances, four specific challenges, and four perspectives on future directions. SIGNIFICANCE STATEMENT: PXR and CAR are key transcription factors that regulate homeostatic detoxification of the liver and intestines. Diverse chemicals bind to these nuclear receptors, triggering their transcriptional tuning of the cellular metabolic response. This minireview revisits the importance of PXR and CAR in pharmaceutical drug responses and highlights recent results with implications beyond drug metabolism.
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Affiliation(s)
- Shyaron Poudel
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Andrew D Huber
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee
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Kamaraj R, Drastik M, Maixnerova J, Pavek P. Allosteric Antagonism of the Pregnane X Receptor (PXR): Current-State-of-the-Art and Prediction of Novel Allosteric Sites. Cells 2022; 11:2974. [PMID: 36230936 PMCID: PMC9563780 DOI: 10.3390/cells11192974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/20/2022] [Accepted: 09/20/2022] [Indexed: 11/26/2022] Open
Abstract
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.
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Affiliation(s)
- Rajamanikkam Kamaraj
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, 50005 Hradec Kralove, Czech Republic
| | - Martin Drastik
- Department of Physical Chemistry and Biophysics, Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, 50005 Hradec Kralove, Czech Republic
| | - Jana Maixnerova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, 50005 Hradec Kralove, Czech Republic
| | - Petr Pavek
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, 50005 Hradec Kralove, Czech Republic
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Influence of Gut–Liver Axis on Portal Hypertension in Advanced Chronic Liver Disease: The Gut Microbiome as a New Protagonist in Therapeutic Management. MICROBIOLOGY RESEARCH 2022. [DOI: 10.3390/microbiolres13030038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Clinically significant portal hypertension is associated with most complications of advanced chronic liver disease (ACLD), including variceal bleeding, ascites, spontaneous bacterial peritonitis, hepatorenal syndrome, and hepatic encephalopathy. Gut dysbiosis is a hallmark of ACLD with portal hypertension and consists of the overgrowth of potentially pathogenic bacteria and a decrease in autochthonous bacteria; additionally, congestion makes the intestinal barrier more permeable to bacteria and their products, which contributes to the development of complications through inflammatory mechanisms. This review summarizes current knowledge on the role of the gut–liver axis in the pathogenesis of portal hypertension, with a focus on therapies targeting portal hypertension and the gut microbiota. The modulation of the gut microbiota on several levels represents a major challenge in the upcoming years; in-depth characterization of the molecular and microbiological mechanisms linking the gut–liver axis to portal hypertension in a bidirectional relationship could pave the way to the identification of new therapeutic targets for innovative therapies in the management of ACLD.
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Bautista-Olivier CD, Elizondo G. PXR as the tipping point between innate immune response, microbial infections, and drug metabolism. Biochem Pharmacol 2022; 202:115147. [PMID: 35714683 DOI: 10.1016/j.bcp.2022.115147] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 11/30/2022]
Abstract
Pregnane X receptor (PXR) is a xenosensor that acts as a transcription factor in the cell nucleus to protect cells from toxic insults. In response to exposure to several chemical agents, PXR induces the expression of enzymes and drug transporters that biotransform xenobiotic and endobiotic and eliminate metabolites. Recently, PXR has been shown to have immunomodulatory effects that involve cross-communication with molecular pathways in innate immunity cells. Conversely, several inflammatory factors regulate PXR signaling. This review examines the crosstalk between PXR and nuclear factor kappa B (NFkB), Toll-like receptors (TLRs), and inflammasome components. Discussions of the consequences of these interactions on immune responses to infections caused by viruses, bacteria, fungi, and parasites are included together with a review of the effects of microorganisms on PXR-associated drug metabolism. This paper aims to encourage researchers to pursue studies that will better elucidate the relationship between PXR and the immune system and thus inform treatment development.
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Affiliation(s)
| | - Guillermo Elizondo
- Departamento de Biología Celular, CINVESTAV-IPN, Av. IPN 2508, C.P. 07360, Ciudad de México, Mexico.
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14
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Savarino E, Zingone F, Barberio B, Marasco G, Akyuz F, Akpinar H, Barboi O, Bodini G, Bor S, Chiarioni G, Cristian G, Corsetti M, Di Sabatino A, Dimitriu AM, Drug V, Dumitrascu DL, Ford AC, Hauser G, Nakov R, Patel N, Pohl D, Sfarti C, Serra J, Simrén M, Suciu A, Tack J, Toruner M, Walters J, Cremon C, Barbara G. Functional bowel disorders with diarrhoea: Clinical guidelines of the United European Gastroenterology and European Society for Neurogastroenterology and Motility. United European Gastroenterol J 2022; 10:556-584. [PMID: 35695704 PMCID: PMC9278595 DOI: 10.1002/ueg2.12259] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 05/20/2022] [Indexed: 11/23/2022] Open
Abstract
Irritable bowel syndrome with diarrhoea (IBS‐D) and functional diarrhoea (FDr) are the two major functional bowel disorders characterized by diarrhoea. In spite of their high prevalence, IBS‐D and FDr are associated with major uncertainties, especially regarding their optimal diagnostic work‐up and management. A Delphi consensus was performed with experts from 10 European countries who conducted a literature summary and voting process on 31 statements. Quality of evidence was evaluated using the grading of recommendations, assessment, development, and evaluation criteria. Consensus (defined as >80% agreement) was reached for all the statements. The panel agreed with the potential overlapping of IBS‐D and FDr. In terms of diagnosis, the consensus supports a symptom‐based approach also with the exclusion of alarm symptoms, recommending the evaluation of full blood count, C‐reactive protein, serology for coeliac disease, and faecal calprotectin, and consideration of diagnosing bile acid diarrhoea. Colonoscopy with random biopsies in both the right and left colon is recommended in patients older than 50 years and in presence of alarm features. Regarding treatment, a strong consensus was achieved for the use of a diet low fermentable oligo‐, di‐, monosaccharides and polyols, gut‐directed psychological therapies, rifaximin, loperamide, and eluxadoline. A weak or conditional recommendation was achieved for antispasmodics, probiotics, tryciclic antidepressants, bile acid sequestrants, 5‐hydroxytryptamine‐3 antagonists (i.e. alosetron, ondansetron, or ramosetron). A multinational group of European experts summarized the current state of consensus on the definition, diagnosis, and management of IBS‐D and FDr.
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Affiliation(s)
- Edoardo Savarino
- Gastroenterology Unit, Department of Surgery, Oncology and Gastroenterology, University of Padua, Padua, Italy
| | - Fabiana Zingone
- Gastroenterology Unit, Department of Surgery, Oncology and Gastroenterology, University of Padua, Padua, Italy
| | - Brigida Barberio
- Gastroenterology Unit, Department of Surgery, Oncology and Gastroenterology, University of Padua, Padua, Italy
| | - Giovanni Marasco
- Division of Internal Medicine, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy.,Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Filiz Akyuz
- Department of Gastroenterology, İstanbul University İstanbul School of Medicine, İstanbul, Turkey
| | - Hale Akpinar
- Department of Internal Medicine, Dokuz Eylül University School of Medicine, Izmir, Turkey
| | - Oana Barboi
- Department of Gastroenterology, 'Grigore T. Popa' University of Medicine and Pharmacy, Iasi, Romania.,Institute of Gastroenterology and Hepatology, 'Saint Spiridon' Hospital, Iasi, Romania
| | - Giorgia Bodini
- Gastrointestinal Unit, Department of Internal Medicine, University of Genoa, Genoa, Italy
| | - Serhat Bor
- Division of Gastroenterology, Ege University School of Medicine, Izmir, Turkey
| | | | - Gheorghe Cristian
- Fundeni Clinical Institute Center of Gastroenterology and Hepatology, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Maura Corsetti
- National Institute for Health Research, Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust, Nottingham, UK.,Nottingham Digestive Diseases Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Antonio Di Sabatino
- First Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, University of Pavia, Pavia, Italy
| | - Anca Mirela Dimitriu
- Center of Gastroenterology and Hepatology, Fundeni Clinical Institute, University of Medicine and Pharmacy, Bucharest, Romania
| | - Vasile Drug
- Department of Gastroenterology, 'Grigore T. Popa' University of Medicine and Pharmacy, Iasi, Romania.,Institute of Gastroenterology and Hepatology, 'Saint Spiridon' Hospital, Iasi, Romania
| | - Dan L Dumitrascu
- 2nd Department of Internal Medicine, 'Iuliu Hatieganu' University of Medicine and Farmacy, Cluj-Napoca, Romania
| | - Alexander C Ford
- Leeds Gastroenterology Institute, Leeds Teaching Hospitals NHS Trust, Leeds, UK.,Leeds Institute of Medical Research at St. James's Sciences, University of Leeds, Leeds, UK
| | - Goran Hauser
- Department of Gastroenterology, Clinical Hospital Center Rijeka, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Radislav Nakov
- Department of Gastroenterology, Tsaritsa Yoanna University Hospital, Medical University of Sofia, Sofia, Bulgaria
| | - Nisha Patel
- Imperial College Healthcare NHS Trust, Institute of Global Health Innovation, St Mary's Hospital Campus, London, UK
| | - Daniel Pohl
- Department of Gastroenterology, University Hospital Zurich, Zurich, Switzerland
| | - Cătălin Sfarti
- Department of Gastroenterology, 'Grigore T. Popa' University of Medicine and Pharmacy, Iasi, Romania.,Institute of Gastroenterology and Hepatology, 'Saint Spiridon' Hospital, Iasi, Romania
| | - Jordi Serra
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Badalona, Spain.,Digestive System Research Unit, University Hospital Vall d'Hebron, Barcelona, Spain.,Department of Medicine, Autonomous University of Barcelona, Badalona, Spain
| | - Magnus Simrén
- Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Alina Suciu
- Center of Gastroenterology and Hepatology, Fundeni Clinical Institute, University of Medicine and Pharmacy, Bucharest, Romania
| | - Jan Tack
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | - Murat Toruner
- Department of Gastroenterology, Ankara University School of Medicine, Ankara, Turkey
| | - Julian Walters
- Division of Digestive Diseases, Department of Metabolism, Digestion, and Reproduction, Faculty of Medicine, Imperial College London, London, UK.,Department of Gastroenterology, Division of Medicine and Integrated Care, Imperial College Healthcare NHS Trust, London, UK
| | - Cesare Cremon
- Division of Internal Medicine, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy.,Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Giovanni Barbara
- Division of Internal Medicine, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy.,Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
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15
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Reducing neuroinflammation via therapeutic compounds and lifestyle to prevent or delay progression of Parkinson's disease. Ageing Res Rev 2022; 78:101618. [PMID: 35395416 DOI: 10.1016/j.arr.2022.101618] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 03/08/2022] [Accepted: 04/01/2022] [Indexed: 02/06/2023]
Abstract
Parkinson's disease (PD) is the second most common age-associated neurodegenerative disorder and is characterised by progressive loss of dopamine neurons in the substantia nigra. Peripheral immune cell infiltration and activation of microglia and astrocytes are observed in PD, a process called neuroinflammation. Neuroinflammation is a fundamental response to protect the brain but, when chronic, it triggers neuronal damage. In the last decade, central and peripheral inflammation were suggested to occur at the prodromal stage of PD, sustained throughout disease progression, and may play a significant role in the pathology. Understanding the pathological mechanisms of PD has been a high priority in research, primarily to find effective treatments once symptoms are present. Evidence indicates that early life exposure to neuroinflammation as a consequence of life events, environmental or behaviour factors such as exposure to infections, pollution or a high fat diet increase the risk of developing PD. Many studies show healthy habits and products that decrease neuroinflammation also reduce the risk of PD. Here, we aim to stimulate discussion about the role of neuroinflammation in PD onset and progression. We highlight that reducing neuroinflammation throughout the lifespan is critical for preventing idiopathic PD, and present epidemiological studies that detail risk and protective factors. It is possible that introducing lifestyle changes that reduce neuroinflammation at the time of PD diagnosis may slow symptom progression. Finally, we discuss compounds and therapeutics to treat the neuroinflammation associated with PD.
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16
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Abstract
Gastrointestinal microbes respond to biochemical metabolites that coordinate their behaviors. Here, we demonstrate that bacterial indole functions as a multifactorial mitigator of Klebsiella grimontii and Klebsiella oxytoca pathogenicity. These closely related microbes produce the enterotoxins tilimycin and tilivalline; cytotoxin-producing strains are the causative agent of antibiotic-associated hemorrhagic colitis and have been associated with necrotizing enterocolitis of premature infants. We demonstrate that carbohydrates induce cytotoxin synthesis while concurrently repressing indole biosynthesis. Conversely, indole represses cytotoxin production. In both cases, the alterations stemmed from differential transcription of npsA and npsB, key genes involved in tilimycin biosynthesis. Indole also enhances conversion of tilimycin to tilivalline, an indole analog with reduced cytotoxicity. In this context, we established that tilivalline, but not tilimycin, is a strong agonist of pregnane X receptor (PXR), a master regulator of xenobiotic detoxification and intestinal inflammation. Tilivalline binding upregulated PXR-responsive detoxifying genes and inhibited tubulin-directed toxicity. Bacterial indole, therefore, acts in a multifunctional manner to mitigate cytotoxicity by Klebsiella spp.: suppression of toxin production, enhanced conversion of tilimycin to tilivalline, and activation of PXR. IMPORTANCE The human gut harbors a complex community of microbes, including several species and strains that could be commensals or pathogens depending on context. The specific environmental conditions under which a resident microbe changes its relationship with a host and adopts pathogenic behaviors, in many cases, remain poorly understood. Here, we describe a novel communication network involving the regulation of K. grimontii and K. oxytoca enterotoxicity. Bacterial indole was identified as a central modulator of these colitogenic microbes by suppressing bacterial toxin (tilimycin) synthesis and converting tilimycin to tilivalline while simultaneously activating a host receptor, PXR, as a means of mitigating tissue cytotoxicity. On the other hand, fermentable carbohydrates were found to inhibit indole biosynthesis and enhance toxin production. This integrated network involving microbial, host, and metabolic factors provides a contextual framework to better understand K. oxytoca complex pathogenicity.
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17
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Karpale M, Hukkanen J, Hakkola J. Nuclear Receptor PXR in Drug-Induced Hypercholesterolemia. Cells 2022; 11:cells11030313. [PMID: 35159123 PMCID: PMC8833906 DOI: 10.3390/cells11030313] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/13/2022] [Accepted: 01/14/2022] [Indexed: 12/13/2022] Open
Abstract
Atherosclerosis is a major global health concern. The central modifiable risk factors and causative agents of the disease are high total and low-density lipoprotein (LDL) cholesterol. To reduce morbidity and mortality, a thorough understanding of the factors that influence an individual’s cholesterol status during the decades when the arteria-narrowing arteriosclerotic plaques are forming is critical. Several drugs are known to increase cholesterol levels; however, the mechanisms are poorly understood. Activation of pregnane X receptor (PXR), the major regulator of drug metabolism and molecular mediator of clinically significant drug–drug interactions, has been shown to induce hypercholesterolemia. As a major sensor of the chemical environment, PXR may in part mediate hypercholesterolemic effects of drug treatment. This review compiles the current knowledge of PXR in cholesterol homeostasis and discusses the role of PXR in drug-induced hypercholesterolemia.
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Affiliation(s)
- Mikko Karpale
- Research Unit of Biomedicine, Biocenter Oulu, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, P.O. Box 5000, FI-90014 Oulu, Finland;
| | - Janne Hukkanen
- Research Unit of Internal Medicine, Biocenter Oulu, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, P.O. Box 5000, FI-90014 Oulu, Finland;
| | - Jukka Hakkola
- Research Unit of Biomedicine, Biocenter Oulu, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, P.O. Box 5000, FI-90014 Oulu, Finland;
- Correspondence:
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18
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Rogers RS, Parker A, Vainer PD, Elliott E, Sudbeck D, Parimi K, Peddada VP, Howe PG, D’Ambrosio N, Ruddy G, Stackable K, Carney M, Martin L, Osterholt T, Staudinger JL. The Interface between Cell Signaling Pathways and Pregnane X Receptor. Cells 2021; 10:cells10113262. [PMID: 34831484 PMCID: PMC8617909 DOI: 10.3390/cells10113262] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 11/15/2021] [Accepted: 11/16/2021] [Indexed: 12/19/2022] Open
Abstract
Highly expressed in the enterohepatic system, pregnane X receptor (PXR, NR1I2) is a well-characterized nuclear receptor (NR) that regulates the expression of genes in the liver and intestines that encode key drug metabolizing enzymes and drug transporter proteins in mammals. The net effect of PXR activation is to increase metabolism and clear drugs and xenobiotics from the body, producing a protective effect and mediating clinically significant drug interaction in patients on combination therapy. The complete understanding of PXR biology is thus important for the development of safe and effective therapeutic strategies. Furthermore, PXR activation is now known to specifically transrepress the inflammatory- and nutrient-signaling pathways of gene expression, thereby providing a mechanism for linking these signaling pathways together with enzymatic drug biotransformation pathways in the liver and intestines. Recent research efforts highlight numerous post-translational modifications (PTMs) which significantly influence the biological function of PXR. However, this thrust of research is still in its infancy. In the context of gene-environment interactions, we present a review of the recent literature that implicates PXR PTMs in regulating its clinically relevant biology. We also provide a discussion of how these PTMs likely interface with each other to respond to extracellular cues to appropriately modify PXR activity.
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Affiliation(s)
- Robert S. Rogers
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin, MO 64804, USA; (R.S.R.); (A.P.); (P.D.V.); (E.E.); (D.S.); (V.P.P.); (P.G.H.); (G.R.); (K.S.); (M.C.); (L.M.); (T.O.)
| | - Annemarie Parker
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin, MO 64804, USA; (R.S.R.); (A.P.); (P.D.V.); (E.E.); (D.S.); (V.P.P.); (P.G.H.); (G.R.); (K.S.); (M.C.); (L.M.); (T.O.)
| | - Phill D. Vainer
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin, MO 64804, USA; (R.S.R.); (A.P.); (P.D.V.); (E.E.); (D.S.); (V.P.P.); (P.G.H.); (G.R.); (K.S.); (M.C.); (L.M.); (T.O.)
| | - Elijah Elliott
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin, MO 64804, USA; (R.S.R.); (A.P.); (P.D.V.); (E.E.); (D.S.); (V.P.P.); (P.G.H.); (G.R.); (K.S.); (M.C.); (L.M.); (T.O.)
| | - Dakota Sudbeck
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin, MO 64804, USA; (R.S.R.); (A.P.); (P.D.V.); (E.E.); (D.S.); (V.P.P.); (P.G.H.); (G.R.); (K.S.); (M.C.); (L.M.); (T.O.)
| | - Kaushal Parimi
- Thomas Jefferson Independent Day School, Joplin, MO 64801, USA;
| | - Venkata P. Peddada
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin, MO 64804, USA; (R.S.R.); (A.P.); (P.D.V.); (E.E.); (D.S.); (V.P.P.); (P.G.H.); (G.R.); (K.S.); (M.C.); (L.M.); (T.O.)
| | - Parker G. Howe
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin, MO 64804, USA; (R.S.R.); (A.P.); (P.D.V.); (E.E.); (D.S.); (V.P.P.); (P.G.H.); (G.R.); (K.S.); (M.C.); (L.M.); (T.O.)
| | - Nick D’Ambrosio
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin, MO 64804, USA; (R.S.R.); (A.P.); (P.D.V.); (E.E.); (D.S.); (V.P.P.); (P.G.H.); (G.R.); (K.S.); (M.C.); (L.M.); (T.O.)
| | - Gregory Ruddy
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin, MO 64804, USA; (R.S.R.); (A.P.); (P.D.V.); (E.E.); (D.S.); (V.P.P.); (P.G.H.); (G.R.); (K.S.); (M.C.); (L.M.); (T.O.)
| | - Kaitlin Stackable
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin, MO 64804, USA; (R.S.R.); (A.P.); (P.D.V.); (E.E.); (D.S.); (V.P.P.); (P.G.H.); (G.R.); (K.S.); (M.C.); (L.M.); (T.O.)
| | - Megan Carney
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin, MO 64804, USA; (R.S.R.); (A.P.); (P.D.V.); (E.E.); (D.S.); (V.P.P.); (P.G.H.); (G.R.); (K.S.); (M.C.); (L.M.); (T.O.)
| | - Lauren Martin
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin, MO 64804, USA; (R.S.R.); (A.P.); (P.D.V.); (E.E.); (D.S.); (V.P.P.); (P.G.H.); (G.R.); (K.S.); (M.C.); (L.M.); (T.O.)
| | - Thomas Osterholt
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin, MO 64804, USA; (R.S.R.); (A.P.); (P.D.V.); (E.E.); (D.S.); (V.P.P.); (P.G.H.); (G.R.); (K.S.); (M.C.); (L.M.); (T.O.)
| | - Jeff L. Staudinger
- Division of Basic Sciences, Farber-McIntire Campus, College of Osteopathic Medicine, Kansas City University, Joplin, MO 64804, USA; (R.S.R.); (A.P.); (P.D.V.); (E.E.); (D.S.); (V.P.P.); (P.G.H.); (G.R.); (K.S.); (M.C.); (L.M.); (T.O.)
- Correspondence:
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Rigalli JP, Theile D, Nilles J, Weiss J. Regulation of PXR Function by Coactivator and Corepressor Proteins: Ligand Binding Is Just the Beginning. Cells 2021; 10:cells10113137. [PMID: 34831358 PMCID: PMC8625645 DOI: 10.3390/cells10113137] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 12/13/2022] Open
Abstract
The pregnane X receptor (PXR, NR1I2) is a nuclear receptor which exerts its regulatory function by heterodimerization with the retinoid-X-receptor α (RXRα, NR2B1) and binding to the promoter and enhancer regions of diverse target genes. PXR is involved in the regulation of drug metabolism and excretion, metabolic and immunological functions and cancer pathogenesis. PXR activity is strongly regulated by the association with coactivator and corepressor proteins. Coactivator proteins exhibit histone acetyltransferase or histone methyltransferase activity or associate with proteins having one of these activities, thus promoting chromatin decondensation and activation of the gene expression. On the contrary, corepressor proteins promote histone deacetylation and therefore favor chromatin condensation and repression of the gene expression. Several studies pointed to clear cell- and ligand-specific differences in the activation of PXR. In this article, we will review the critical role of coactivator and corepressor proteins as molecular determinants of the specificity of PXR-mediated effects. As already known for other nuclear receptors, understanding the complex mechanism of PXR activation in each cell type and under particular physiological and pathophysiological conditions may lead to the development of selective modulators with therapeutic potential.
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20
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Caraceni P, Vargas V, Solà E, Alessandria C, de Wit K, Trebicka J, Angeli P, Mookerjee RP, Durand F, Pose E, Krag A, Bajaj JS, Beuers U, Ginès P, Napoleone L, Carol M, Avitabile E, Thu AM, Cervera M, Pérez M, Belén Rubio‐Garcia A, Ardiaca A, Vives A, Pich J, Fabrellas N, Zaccherini G, Chiappa MT, Jiménez C, Palacio E, Campion D, Lanzillotti T, Piano S, Nicolao G, Uschner F, Graf_Dirmeier S, Francoz C, Roux O, Esnault V, Helder J, Aban M, Kazankov K, Korenjak M, Kamath P, Abraldes JG, Watson H. The Use of Rifaximin in Patients With Cirrhosis. Hepatology 2021; 74:1660-1673. [PMID: 33421158 PMCID: PMC8518409 DOI: 10.1002/hep.31708] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 11/10/2020] [Accepted: 12/02/2020] [Indexed: 12/12/2022]
Abstract
Rifaximin is an oral nonsystemic antibiotic with minimal gastrointestinal absorption and broad-spectrum antibacterial activity covering both gram-positive and gram-negative organisms. Rifaximin is currently used worldwide in patients with cirrhosis for preventing recurrent HE because its efficacy and safety have been proven by large randomized clinical trials. In the last decade, experimental and clinical evidence suggest that rifaximin could have other beneficial effects on the course of cirrhosis by modulating the gut microbiome and affecting the gut-liver axis, which in turn can interfere with major events of the pathophysiological cascade underlying decompensated cirrhosis, such as systemic inflammatory syndrome, portal hypertension, and bacterial infections. However, the use of rifaximin for prevention or treatment of other complications, including spontaneous bacterial peritonitis or other bacterial infections, is not accepted because evidence by clinical trials is still very weak. The present review deals in the first part with the potential impact of rifaximin on pathogenic mechanisms in liver diseases, whereas in the second part, its clinical effects are critically discussed. It clearly emerges that, because of its potential activity on multiple pathogenic events, the efficacy of rifaximin in the prevention or management of complications other than HE deserves to be investigated extensively. The results of double-blinded, adequately powered randomized clinical trials assessing the effect of rifaximin, alone or in combination with other drugs, on hard clinical endpoints, such as decompensation of cirrhosis, acute-on-chronic liver failure, and mortality, are therefore eagerly awaited.
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Affiliation(s)
- Paolo Caraceni
- University of BolognaUniversity Hospital S. Orsola‐Malpighi di BolognaBolognaItaly
| | - Victor Vargas
- Hospital Vall d’HebronUniversitat Autònoma de BarcelonaCIEREHDBarcelonaCataloniaSpain
| | - Elsa Solà
- Hospital Clinic of BarcelonaUniversity of BarcelonaIDIBAPSCIBEReHDBarcelonaCataloniaSpain
| | - Carlo Alessandria
- Division of Gastroenterology and HepatologyCittà della Salute e della Scienza HospitalUniversity of TorinoTurinItaly
| | - Koos de Wit
- Amsterdam University Medical CentersAmsterdamthe Netherlands
| | - Jonel Trebicka
- Goethe‐University ‐ Frankfurt am MainFrankfurt am MainGermany,EF‐CLIFBarcelonaCataloniaSpain
| | | | | | | | - Elisa Pose
- Hospital Clinic of BarcelonaUniversity of BarcelonaIDIBAPSCIBEReHDBarcelonaCataloniaSpain
| | - Aleksander Krag
- Department of Gastroenterology and HepatologyOdense University HospitalOdenseDenmark,Institute of Clinical ResearchUniversity of Southern DenmarkOdenseDenmark
| | | | - Ulrich Beuers
- Amsterdam University Medical CentersAmsterdamthe Netherlands
| | - Pere Ginès
- Hospital Clinic of BarcelonaUniversity of BarcelonaIDIBAPSCIBEReHDBarcelonaCataloniaSpain
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21
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Gu Z, Duan M, Sun Y, Leng T, Xu T, Gu Y, Gu Z, Lin Z, Yang L, Ji M. Effects of Vitamin D3 on Intestinal Flora in a Mouse Model of Inflammatory Bowel Disease Treated with Rifaximin. Med Sci Monit 2020; 26:e925068. [PMID: 33177483 PMCID: PMC7670830 DOI: 10.12659/msm.925068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Rifaximin is an antimicrobial agent used to treat inflammatory bowel disease (IBD). Vitamin D3 can control IBD due to its effects on inflammatory cytokines. The purpose of this study was to assess the effect of vitamin D3 on the intestinal flora of a dextran sulfate sodium (DSS)-induced mouse model treated with rifaximin. MATERIAL AND METHODS The mouse model of IBD was developed using DSS (4%) administered via the drinking water. Twenty-four male C57BL6 mice were divided into the control group with a normal diet (N=6), the DSS group with a normal diet (N=6), the DSS group with a normal diet treated with rifaximin (N=6), and the DSS group with a normal diet treated with rifaximin and vitamin D3 (N=6). After 14 days, the colonic tissue was studied histologically. Serum levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1ß (IL-1ß) and enzyme-linked immunosorbent assay (ELISA) were used to measure the level of IL-6 and P65, and phospho-p65 was measured by western blot. 16S rRNA gene sequencing was used to analyze fecal samples. RESULTS In the DSS mouse model of IBD, rifaximin reduced the inflammation severity of the colon and reduced the expression of phospho-p65, p65, TNF-alpha, and IL-6. In the DSS+rifaximin+vitamin D3 group, the therapeutic influences of rifaximin, in terms of weight loss and colonic disease activity, were significantly reduced, and the gut microbiota of the mice were completely changed in composition and diversity. CONCLUSIONS In a mouse model of IBD, treatment with vitamin D3 significantly increased the metabolism of rifaximin and reduced its therapeutic effects.
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Affiliation(s)
- Zijun Gu
- School of Nursing, Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
| | - Mingxiu Duan
- School of Public Health, Bengbu Medical College, Bengbu, Anhui, China (mainland)
| | - Yan Sun
- School of Nursing, Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
| | - Tian Leng
- School of Nursing, Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
| | - Ting Xu
- School of Nursing, Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
| | - Yang Gu
- School of Nursing, Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
| | - Zejuan Gu
- School of Nursing, Nanjing Medical University, Nanjing, Jiangsu, China (mainland).,The First Affiliated Hospital with Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
| | - Zheng Lin
- School of Nursing, Nanjing Medical University, Nanjing, Jiangsu, China (mainland).,The First Affiliated Hospital with Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
| | - Lu Yang
- School of Nursing, Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
| | - Minghui Ji
- School of Nursing, Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
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22
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Rifaximin Alleviates Endotoxemia with Decreased Serum Levels of Soluble CD163 and Mannose Receptor and Partial Modification of Gut Microbiota in Cirrhotic Patients. Antibiotics (Basel) 2020; 9:antibiotics9040145. [PMID: 32235367 PMCID: PMC7235723 DOI: 10.3390/antibiotics9040145] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 03/24/2020] [Accepted: 03/26/2020] [Indexed: 12/24/2022] Open
Abstract
Rifaximin is a poorly absorbable antibiotic against hepatic encephalopathy (HE). This observational study aimed to elucidate the effect of rifaximin on intestinal permeability and gut microbiota in patients with decompensated cirrhosis. Thirty patients with decompensated cirrhosis were assessed by ammonia level, neuropsychological testing, endotoxin activity (EA), and serum proinflammatory cytokines at baseline and after four weeks of rifaximin treatment (1200 mg/day). Intestinal permeability was indicated by serum soluble CD163 (sCD163), mannose receptor (sMR), and zonulin levels. To evaluate the gut microbiome, 16S ribosomal RNA gene sequencing was applied. Rifaximin ameliorated hyperammonemia and cognitive dysfunction, although it did not change the serum proinflammatory cytokine levels. It decreased EA levels as well as serum levels of sCD163 and sMR, but not zonulin, and both decreases in sCD163 and sMR showed positive correlations with EA decrease (ΔsCD163: Correlation coefficient (R) = 0.680, p = 0.023; ΔsMR: R = 0.613, p = 0.014, vs. ΔEA). Gut microbial analysis revealed that the richness and complexity of species were unchanged while the abundance of the Streptococcus genus was reduced after treatment with rifaximin. Collectively, rifaximin alleviated HE and endotoxemia with improved intestinal hyperpermeability in patients with decompensated cirrhosis, and this effect is partially involved in a gut microbial change.
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23
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Xing Y, Yan J, Niu Y. PXR: a center of transcriptional regulation in cancer. Acta Pharm Sin B 2020; 10:197-206. [PMID: 32082968 PMCID: PMC7016272 DOI: 10.1016/j.apsb.2019.06.012] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 06/10/2019] [Accepted: 06/20/2019] [Indexed: 02/05/2023] Open
Abstract
Pregnane X receptor (PXR, NR1I2) is a prototypical member of the nuclear receptor superfamily. PXR can be activated by both endobiotics and xenobiotics. As a key xenobiotic receptor, the cellular function of PXR is mostly exerted by its binding to the regulatory gene sequences in a ligand-dependent manner. Classical downstream target genes of PXR participate in xenobiotic responses, such as detoxification, metabolism and inflammation. Emerging evidence also implicates PXR signaling in the processes of apoptosis, cell cycle arrest, proliferation, angiogenesis and oxidative stress, which are closely related to cancer. Here, we discussed, in addition to the characterization of PXR per se, the biological function and regulatory mechanism of PXR signaling in cancer, and its potential for the targeted prevention and therapeutics.
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Affiliation(s)
- Yaqi Xing
- Department of Pharmacology, Shantou University Medical College, Shantou 515041, China
| | - Jiong Yan
- Center for Pharmacogenetics, University of Pittsburgh, PA 15261, USA
| | - Yongdong Niu
- Department of Pharmacology, Shantou University Medical College, Shantou 515041, China
- Corresponding author.
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24
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Chey WD, Shah ED, DuPont HL. Mechanism of action and therapeutic benefit of rifaximin in patients with irritable bowel syndrome: a narrative review. Therap Adv Gastroenterol 2020; 13:1756284819897531. [PMID: 32047534 PMCID: PMC6984424 DOI: 10.1177/1756284819897531] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 12/02/2019] [Indexed: 02/04/2023] Open
Abstract
Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder with a multifactorial pathophysiology. The gut microbiota differs between patients with IBS and healthy individuals. After a bout of acute gastroenteritis, postinfection IBS may result in up to approximately 10% of those affected. Small intestinal bacterial overgrowth (SIBO) is more common in patients with IBS than in healthy individuals, and eradication of SIBO with systemic antibiotics has decreased symptoms of IBS in some patients with IBS and SIBO. The nonsystemic (i.e. low oral bioavailability) antibiotic rifaximin is indicated in the United States and Canada for the treatment of adults with IBS with diarrhea (IBS-D). The efficacy and safety of 2-week single and repeat courses of rifaximin have been demonstrated in randomized, placebo-controlled studies of adults with IBS. Rifaximin is widely thought to exert its beneficial clinical effects in IBS-D through manipulation of the gut microbiota. However, current studies indicate that rifaximin induces only modest effects on the gut microbiota of patients with IBS-D, suggesting that the efficacy of rifaximin may involve other mechanisms. Indeed, preclinical data reveal a potential role for rifaximin in the modulation of inflammatory cytokines and intestinal permeability, but these two findings have not yet been examined in the context of clinical studies. The mechanism of action of rifaximin in IBS is likely multifactorial, and further study is needed.
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Affiliation(s)
- William D. Chey
- Department of Nutrition Sciences, Division of Gastroenterology, Michigan Medicine, 3912 Taubman Center, SPC 5362, Ann Arbor, MI 48109-5362, USA
| | - Eric D. Shah
- Section of Gastroenterology and Hepatology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - Herbert L. DuPont
- Division of Epidemiology, Human Genetics and Environmental Sciences and Center for Infectious Diseases, University of Texas School of Public Health, Houston, TX, USA
- Mary W. Kelsey Chair in Medical Sciences, Division of Internal Medicine, University of Texas McGovern Medical School Houston, TX, USA
- Kelsey Research Foundation, Houston, TX, USA
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25
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Das NK, Schwartz AJ, Barthel G, Inohara N, Liu Q, Sankar A, Hill DR, Ma X, Lamberg O, Schnizlein MK, Arqués JL, Spence JR, Nunez G, Patterson AD, Sun D, Young VB, Shah YM. Microbial Metabolite Signaling Is Required for Systemic Iron Homeostasis. Cell Metab 2020; 31:115-130.e6. [PMID: 31708445 PMCID: PMC6949377 DOI: 10.1016/j.cmet.2019.10.005] [Citation(s) in RCA: 155] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 09/23/2019] [Accepted: 10/14/2019] [Indexed: 12/16/2022]
Abstract
Iron is a central micronutrient needed by all living organisms. Competition for iron in the intestinal tract is essential for the maintenance of indigenous microbial populations and for host health. How symbiotic relationships between hosts and native microbes persist during times of iron limitation is unclear. Here, we demonstrate that indigenous bacteria possess an iron-dependent mechanism that inhibits host iron transport and storage. Using a high-throughput screen of microbial metabolites, we found that gut microbiota produce metabolites that suppress hypoxia-inducible factor 2α (HIF-2α) a master transcription factor of intestinal iron absorption and increase the iron-storage protein ferritin, resulting in decreased intestinal iron absorption by the host. We identified 1,3-diaminopropane (DAP) and reuterin as inhibitors of HIF-2α via inhibition of heterodimerization. DAP and reuterin effectively ameliorated systemic iron overload. This work provides evidence of intestine-microbiota metabolic crosstalk that is essential for systemic iron homeostasis.
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Affiliation(s)
- Nupur K Das
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Andrew J Schwartz
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gabrielle Barthel
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Naohiro Inohara
- Department of Pathology and Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI 48109, USA
| | - Qing Liu
- Department of Veterinary and Biomedical Sciences, the Pennsylvania State University, University Park, PA 16802, USA
| | - Amanda Sankar
- Department of Pediatrics, Division of Hematology-Oncology, University of Michigan, Ann Arbor, MI 48109, USA
| | - David R Hill
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xiaoya Ma
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Olivia Lamberg
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Matthew K Schnizlein
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Juan L Arqués
- Departamento Tecnología de Alimentos, INIA, Carretera de La Coruña Km 7, Madrid 28040, Spain
| | - Jason R Spence
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gabriel Nunez
- Department of Pathology and Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI 48109, USA
| | - Andrew D Patterson
- Department of Veterinary and Biomedical Sciences, the Pennsylvania State University, University Park, PA 16802, USA
| | - Duxin Sun
- College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, USA
| | - Vincent B Young
- Department of Internal Medicine, Division of Infectious Disease, University of Michigan, Ann Arbor, MI 48109, USA; Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yatrik M Shah
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI 48109, USA.
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26
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Chai SC, Wright WC, Chen T. Strategies for developing pregnane X receptor antagonists: Implications from metabolism to cancer. Med Res Rev 2019; 40:1061-1083. [PMID: 31782213 DOI: 10.1002/med.21648] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/24/2019] [Accepted: 11/19/2019] [Indexed: 12/11/2022]
Abstract
Pregnane X receptor (PXR) is a ligand-activated nuclear receptor (NR) that was originally identified as a master regulator of xenobiotic detoxification. It regulates the expression of drug-metabolizing enzymes and transporters to control the degradation and excretion of endobiotics and xenobiotics, including therapeutic agents. The metabolism and disposition of drugs might compromise their efficacy and possibly cause drug toxicity and/or drug resistance. Because many drugs can promiscuously bind and activate PXR, PXR antagonists might have therapeutic value in preventing and overcoming drug-induced PXR-mediated drug toxicity and drug resistance. Furthermore, PXR is now known to have broader cellular functions, including the regulation of cell proliferation, and glucose and lipid metabolism. Thus, PXR might be involved in human diseases such as cancer and metabolic diseases. The importance of PXR antagonists is discussed in the context of the role of PXR in xenobiotic sensing and other disease-related pathways. This review focuses on the development of PXR antagonists, which has been hampered by the promiscuity of PXR ligand binding. However, substantial progress has been made in recent years, suggesting that it is feasible to develop selective PXR antagonists. We discuss the current status, challenges, and strategies in developing selective PXR antagonists. The strategies are based on the molecular mechanisms of antagonism in related NRs that can be applied to the design of PXR antagonists, primarily driven by structural information.
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Affiliation(s)
- Sergio C Chai
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, Tennessee
| | - William C Wright
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, Tennessee.,Integrated Biomedical Sciences Program, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, Tennessee.,Integrated Biomedical Sciences Program, University of Tennessee Health Science Center, Memphis, Tennessee
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27
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Bajaj JS, Fagan A, Sikaroodi M, Kakiyama G, Takei H, Degefu Y, Pandak WM, Hylemon PB, Fuchs M, John B, Heuman DM, Gavis E, Nittono H, Patil R, Gillevet PM. Alterations in Skin Microbiomes of Patients With Cirrhosis. Clin Gastroenterol Hepatol 2019; 17:2581-2591.e15. [PMID: 30905718 PMCID: PMC6754819 DOI: 10.1016/j.cgh.2019.03.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 03/12/2019] [Accepted: 03/14/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Patients with cirrhosis have intestinal dysbiosis and are prone to itching and skin or soft-tissue infections. The skin microbiome, and its relationship with intestinal microbiome, have not been characterized. We investigated alterations in skin microbiota of patients with cirrhosis and their association with intestinal microbiota and modulators of itch. METHODS We collected skin swabs at 7 sites and blood and stool samples from 20 healthy individuals (control subjects; mean age, 59 years) and 50 patients with cirrhosis (mean age, 61 years; mean model for end-stage disease score, 12; 20 with decompensation). Skin and stool samples were analyzed by 16s rRNA sequencing and serum samples were analyzed by liquid chromatography and mass spectrometry for levels of bile acids (BAs) and by an ELISA for autotaxin (an itch modulator). Participants were analyzed by the visual analog itch scale (VAS, 0-10,10 = maximum intensity). Data were compared between groups (cirrhosis vs control subjects, with vs without decompensation, VAS 5 or higher vs less than 5). Correlation networks between serum levels of BAs and skin microbiomes were compared between patients with cirrhosis with vs without itching. RESULTS The composition of microbiomes at all skin sites differed between control subjects and patients with cirrhosis and between patients with compensated vs decompensated cirrhosis. Skin microbiomes of patients with cirrhosis (especially those with decompensation) contained a higher relative abundance of Gammaproteobacteria, Streptococaceae, and Staphylococcaceae, and fecal microbiomes contained a higher relative abundance of Gammaproteobacteria, than control subjects. These bacterial taxa were associated with serum levels of autotaxin and BAs, which were higher in patients with VAS scores ≥5. Based on network statistics, microbial and BA interactions at all sites were more complex in patients with greater levels of itching in the shin, the most common site of itch. CONCLUSIONS We identified alterations in skin microbiome of patients with cirrhosis (in Gammaproteobacteria, Streptococcaceae, and Staphylococcaceae)-especially in patients with decompensation; fecal microbiomes of patients with cirrhosis had a higher relative abundance of Gammaproteobacteria than control subjects. These specific microbial taxa are associated with itching intensity and itch modulators, such as serum levels of BAs and autotaxin.
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Affiliation(s)
- Jasmohan S Bajaj
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia.
| | - Andrew Fagan
- Division of Gastroenterology, Hepatology and Nutrition,
Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA,
USA
| | - Masoumeh Sikaroodi
- Center for Microbiome Analysis, George Mason University,
Manassas, VA, USA
| | - Genta Kakiyama
- Division of Gastroenterology, Hepatology and Nutrition,
Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA,
USA
| | - Hajme Takei
- Junshin Clinic Bile Acid Institute, Tokyo, Japan
| | - Yordanos Degefu
- Center for Microbiome Analysis, George Mason University,
Manassas, VA, USA
| | - William M Pandak
- Division of Gastroenterology, Hepatology and Nutrition,
Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA,
USA
| | - Phillip B Hylemon
- Division of Gastroenterology, Hepatology and Nutrition,
Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA,
USA
| | - Michael Fuchs
- Division of Gastroenterology, Hepatology and Nutrition,
Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA,
USA
| | - Binu John
- Division of Gastroenterology, Hepatology and Nutrition,
Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA,
USA
| | - Douglas M Heuman
- Division of Gastroenterology, Hepatology and Nutrition,
Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA,
USA
| | - Edith Gavis
- Division of Gastroenterology, Hepatology and Nutrition,
Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA,
USA
| | | | - Rohan Patil
- Center for Microbiome Analysis, George Mason University,
Manassas, VA, USA
| | - Patrick M Gillevet
- Center for Microbiome Analysis, George Mason University,
Manassas, VA, USA
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28
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Liu T, Song X, Khan S, Li Y, Guo Z, Li C, Wang S, Dong W, Liu W, Wang B, Cao H. The gut microbiota at the intersection of bile acids and intestinal carcinogenesis: An old story, yet mesmerizing. Int J Cancer 2019; 146:1780-1790. [DOI: 10.1002/ijc.32563] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/05/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Tianyu Liu
- Department of Gastroenterology and Hepatology, General HospitalTianjin Medical University Tianjin China
| | - Xueli Song
- Department of Gastroenterology and Hepatology, General HospitalTianjin Medical University Tianjin China
| | - Samiullah Khan
- Department of Gastroenterology and Hepatology, General HospitalTianjin Medical University Tianjin China
| | - Yun Li
- Department of Pharmacy, General HospitalTianjin Medical University Tianjin China
| | - Zixuan Guo
- Department of Gastroenterology and Hepatology, General HospitalTianjin Medical University Tianjin China
| | - Chuqiao Li
- Department of Gastroenterology and Hepatology, General HospitalTianjin Medical University Tianjin China
| | - Sinan Wang
- Department of Gastroenterology and Hepatology, General HospitalTianjin Medical University Tianjin China
| | - Wenxiao Dong
- Department of Gastroenterology and Hepatology, General HospitalTianjin Medical University Tianjin China
| | - Wentian Liu
- Department of Gastroenterology and Hepatology, General HospitalTianjin Medical University Tianjin China
| | - Bangmao Wang
- Department of Gastroenterology and Hepatology, General HospitalTianjin Medical University Tianjin China
| | - Hailong Cao
- Department of Gastroenterology and Hepatology, General HospitalTianjin Medical University Tianjin China
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29
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Rosette C, Agan FJ, Rosette N, Moro L, Mazzetti A, Hassan C, Gerloni M. Rifamycin SV exhibits strong anti-inflammatory in vitro activity through pregnane X receptor stimulation and NFκB inhibition. Drug Metab Pharmacokinet 2019; 34:172-180. [DOI: 10.1016/j.dmpk.2019.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 12/24/2018] [Accepted: 01/08/2019] [Indexed: 02/08/2023]
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30
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Hudson G, Flannigan KL, Venu VKP, Alston L, Sandall CF, MacDonald JA, Muruve DA, Chang TKH, Mani S, Hirota SA. Pregnane X Receptor Activation Triggers Rapid ATP Release in Primed Macrophages That Mediates NLRP3 Inflammasome Activation. J Pharmacol Exp Ther 2019; 370:44-53. [PMID: 31004077 PMCID: PMC6542184 DOI: 10.1124/jpet.118.255679] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 04/08/2019] [Indexed: 12/15/2022] Open
Abstract
The pregnane X receptor (PXR) is a ligand-activated nuclear receptor that acts as a xenobiotic sensor, responding to compounds of foreign origin, including pharmaceutical compounds, environmental contaminants, and natural products, to induce transcriptional events that regulate drug detoxification and efflux pathways. As such, the PXR is thought to play a key role in protecting the host from xenobiotic exposure. More recently, the PXR has been reported to regulate the expression of innate immune receptors in the intestine and modulate inflammasome activation in the vasculature. In the current study, we report that activation of the PXR in primed macrophages triggers caspase-1 activation and interleukin-1β release. Mechanistically, we show that this response is nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain-containing 3-dependent and is driven by the rapid efflux of ATP and P2X purinoceptor 7 activation following PXR stimulation, an event that involves pannexin-1 gating, and is sensitive to inhibition of Src-family kinases. Our findings identify a mechanism whereby the PXR drives innate immune signaling, providing a potential link between xenobiotic exposure and the induction of innate inflammatory responses.
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Affiliation(s)
- Grace Hudson
- Departments of Physiology and Pharmacology (G.H., K.L.F., V.K.P.V., L.A., S.A.H.), Biochemistry and Molecular Biology (C.F.S., J.A.M.), Medicine (D.A.M.), and Immunology, Microbiology, and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (T.K.H.C.); and Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (S.M.)
| | - Kyle L Flannigan
- Departments of Physiology and Pharmacology (G.H., K.L.F., V.K.P.V., L.A., S.A.H.), Biochemistry and Molecular Biology (C.F.S., J.A.M.), Medicine (D.A.M.), and Immunology, Microbiology, and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (T.K.H.C.); and Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (S.M.)
| | - Vivek Krishna Pulakazhi Venu
- Departments of Physiology and Pharmacology (G.H., K.L.F., V.K.P.V., L.A., S.A.H.), Biochemistry and Molecular Biology (C.F.S., J.A.M.), Medicine (D.A.M.), and Immunology, Microbiology, and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (T.K.H.C.); and Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (S.M.)
| | - Laurie Alston
- Departments of Physiology and Pharmacology (G.H., K.L.F., V.K.P.V., L.A., S.A.H.), Biochemistry and Molecular Biology (C.F.S., J.A.M.), Medicine (D.A.M.), and Immunology, Microbiology, and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (T.K.H.C.); and Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (S.M.)
| | - Christina F Sandall
- Departments of Physiology and Pharmacology (G.H., K.L.F., V.K.P.V., L.A., S.A.H.), Biochemistry and Molecular Biology (C.F.S., J.A.M.), Medicine (D.A.M.), and Immunology, Microbiology, and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (T.K.H.C.); and Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (S.M.)
| | - Justin A MacDonald
- Departments of Physiology and Pharmacology (G.H., K.L.F., V.K.P.V., L.A., S.A.H.), Biochemistry and Molecular Biology (C.F.S., J.A.M.), Medicine (D.A.M.), and Immunology, Microbiology, and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (T.K.H.C.); and Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (S.M.)
| | - Daniel A Muruve
- Departments of Physiology and Pharmacology (G.H., K.L.F., V.K.P.V., L.A., S.A.H.), Biochemistry and Molecular Biology (C.F.S., J.A.M.), Medicine (D.A.M.), and Immunology, Microbiology, and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (T.K.H.C.); and Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (S.M.)
| | - Thomas K H Chang
- Departments of Physiology and Pharmacology (G.H., K.L.F., V.K.P.V., L.A., S.A.H.), Biochemistry and Molecular Biology (C.F.S., J.A.M.), Medicine (D.A.M.), and Immunology, Microbiology, and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (T.K.H.C.); and Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (S.M.)
| | - Sridhar Mani
- Departments of Physiology and Pharmacology (G.H., K.L.F., V.K.P.V., L.A., S.A.H.), Biochemistry and Molecular Biology (C.F.S., J.A.M.), Medicine (D.A.M.), and Immunology, Microbiology, and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (T.K.H.C.); and Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (S.M.)
| | - Simon A Hirota
- Departments of Physiology and Pharmacology (G.H., K.L.F., V.K.P.V., L.A., S.A.H.), Biochemistry and Molecular Biology (C.F.S., J.A.M.), Medicine (D.A.M.), and Immunology, Microbiology, and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (T.K.H.C.); and Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (S.M.)
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31
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Baffy G. Potential mechanisms linking gut microbiota and portal hypertension. Liver Int 2019; 39:598-609. [PMID: 30312513 DOI: 10.1111/liv.13986] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 10/01/2018] [Accepted: 10/04/2018] [Indexed: 12/11/2022]
Abstract
Gut microbiota is the largest collection of commensal micro-organisms in the human body, engaged in reciprocal cellular and molecular interactions with the liver. This mutually beneficial relationship may break down and result in dysbiosis, associated with disease phenotypes. Altered composition and function of gut microbiota has been implicated in the pathobiology of nonalcoholic fatty liver disease (NAFLD), a prevalent condition linked to obesity, insulin resistance and endothelial dysfunction. NAFLD may progress to cirrhosis and portal hypertension, which is the result of increased intrahepatic vascular resistance and altered splanchnic circulation. Gut microbiota may contribute to rising portal pressure from the earliest stages of NAFLD, although the significance of these changes remains unclear. NAFLD has been linked to lower microbial diversity and weakened intestinal barrier, exposing the host to bacterial components and stimulating pathways of immune defence and inflammation. Moreover, disrupted host-microbial metabolic interplay alters bile acid signalling and the release of vasoregulatory gasotransmitters. These perturbations become prominent in cirrhosis, increasing the risk of clinically significant portal hypertension and leading to bacterial translocation, sepsis and acute-on-chronic liver failure. Better understanding of the gut-liver axis and identification of novel microbial molecular targets may yield specific strategies in the prevention and management of portal hypertension.
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Affiliation(s)
- Gyorgy Baffy
- Department of Medicine, VA Boston Healthcare System and Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
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32
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Chai SC, Lin W, Li Y, Chen T. Drug discovery technologies to identify and characterize modulators of the pregnane X receptor and the constitutive androstane receptor. Drug Discov Today 2019; 24:906-915. [PMID: 30731240 PMCID: PMC6421094 DOI: 10.1016/j.drudis.2019.01.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/27/2018] [Accepted: 01/30/2019] [Indexed: 11/24/2022]
Abstract
The pregnane X receptor (PXR) and the constitutive androstane receptor (CAR) are ligand-activated nuclear receptors (NRs) that are notorious for their role in drug metabolism, causing unintended drug-drug interactions and decreasing drug efficacy. They control the xenobiotic detoxification system by regulating the expression of an array of drug-metabolizing enzymes and transporters that excrete exogenous chemicals and maintain homeostasis of endogenous metabolites. Much effort has been invested in recognizing potential drugs for clinical use that can activate PXR and CAR to enhance the expression of their target genes, and in identifying PXR and CAR inhibitors that can be used as co-therapeutics to prevent adverse effects. Here, we present current technologies and assays used in the quest to characterize PXR and CAR modulators, which range from biochemical to cell-based and animal models.
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Affiliation(s)
- Sergio C Chai
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Wenwei Lin
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Yongtao Li
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Taosheng Chen
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA.
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33
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Di Mario F, Miraglia C, Cambiè G, Violi A, Nouvenne A, Franceschi M, Brandimarte G, Elisei W, Picchio M, Tursi A. Long-term efficacy of rifaximin to manage the symptomatic uncomplicated diverticular disease of the colon. J Investig Med 2018; 67:767-770. [PMID: 30593541 DOI: 10.1136/jim-2018-000901] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2018] [Indexed: 12/20/2022]
Abstract
Although rifaximin is currently advised in managing symptomatic uncomplicated diverticular disease (SUDD) of the colon, no long-term data are available. This retrospective study assessed the outcome of a large cohort of patients with SUDD, treated with rifaximin, during an 8-year follow-up. The study group (group A) included 346 patients with SUDD (median age 64 years, IQR 58-69, 62.4% females), treated with rifaximin 800 mg/d for 7 days every month. The control group (group B) included 470 patients with SUDD (median age 65 years, IQR 59-74 years, 60.8% females), taking any other treatment on demand. Two symptoms (left lower abdominal pain and bloating) were assessed by a visual analog scale (VAS), graded from 0=no symptom to 10=the most severe symptom. Daily bowel movements were also reported. Median (IQR) VAS score for pain was 6 (5-7) in group A and 6 (6-7) in group B at baseline (p=0.109); at 8-year follow-up it was 3 (3-4) and 6 (5-7), respectively (p<0.000). Both bloating and daily bowel movements were significantly reduced in group A. Acute diverticulitis occurred in 9 (2.6%) patients in group A and in 21 (4.5%) patients in group B (p=0.155). Surgery occurred in 4 (1.2%) patients in group A and 9 (1.9%) in group B (p=0.432). Disease-related mortality occurred in no patient in group A and 2 (0.4%) patients in group B (p=0.239). No side effects were recorded during the entire study period. Rifaximin is effective to relieve symptoms and reduce the risk of disease-related complications in patients with SUDD.
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Affiliation(s)
- Francesco Di Mario
- Gastroenterology Unit, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Chiara Miraglia
- Gastroenterology Unit, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Ginevra Cambiè
- Gastroenterology Unit, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Alessandra Violi
- Gastroenterology Unit, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Antonio Nouvenne
- Gastroenterology Unit, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | | | - Giovanni Brandimarte
- Division of Internal Medicine and Gastroenterology, 'Cristo Re' Hospital, Rome, Italy
| | - Walter Elisei
- Division of Gastroenterology, ASL RM6, Albano Laziale, Italy
| | - Marcello Picchio
- Division of Surgery, 'P Colombo' Hospital, ASL RM6, Velletri, Italy
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Lu X, Chan T, Cheng Z, Shams T, Zhu L, Murray M, Zhou F. The 5'-AMP-Activated Protein Kinase Regulates the Function and Expression of Human Organic Anion Transporting Polypeptide 1A2. Mol Pharmacol 2018; 94:1412-1420. [PMID: 30348897 DOI: 10.1124/mol.118.113423] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 09/28/2018] [Indexed: 12/14/2022] Open
Abstract
The organic anion transporting polypeptides (OATPs) are important membrane proteins that mediate the cellular uptake of drugs and endogenous substances. OATP1A2 is widely distributed in many human tissues that are targeted in drug therapy; defective OATP1A2 leads to altered drug disposition influencing therapeutic outcomes. 5'-AMP-activated protein kinase (AMPK) signaling plays an important role in the pathogenesis of the metabolic syndrome characterized by an increased incidence of type II diabetes and nonalcoholic fatty liver disease. This study investigated the regulatory role of AMPK in OATP1A2 transport function and expression. We found that the treatment of AMPK-specific inhibitor compound C (dorsomorphin dihydrochloride) decreased OATP1A2-mediated uptake of estrone-3-sulfate in a concentration- and time-dependent manner. The impaired OATP1A2 function was associated with a reduced Vmax [154.6 ± 17.9 pmol × (μg × 4 minutes)-1 in compound C-treated cells vs. 413.6 ± 52.5 pmol × (μg × 4 minutes)-1 in controls]; the Km was unchanged. The cell-surface expression of OATP1A2 was decreased by compound C treatment, but total cellular expression was unchanged. The impaired cell-surface expression of OATP1A2 was associated with accelerated internalization and impaired targeting/recycling. Silencing of the AMPK α1-subunit using specific small interfering RNA corroborated the findings with compound C and revealed a role for AMPK in regulating OATP1A2 protein stability. Overall, this study implicated AMPK in the regulation of the function and expression of OATP1A2, which potentially impacts on the disposition of OATP1A2 drug substrates that may be used to treat patients with the metabolic syndrome and other diseases.
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Affiliation(s)
- Xiaoxi Lu
- School of Pharmacy (X.L., T.C., Z.C., T.S., F.Z.), Save Sight Institute (L.Z.), and Discipline of Pharmacology (M.M.), Faculty of Medicine and Health, University of Sydney, New South Wales, Australia; and Japanese Foundation for Cancer Research, Koto-ku, Tokyo, Japan (T.C.)
| | - Ting Chan
- School of Pharmacy (X.L., T.C., Z.C., T.S., F.Z.), Save Sight Institute (L.Z.), and Discipline of Pharmacology (M.M.), Faculty of Medicine and Health, University of Sydney, New South Wales, Australia; and Japanese Foundation for Cancer Research, Koto-ku, Tokyo, Japan (T.C.)
| | - Zhengqi Cheng
- School of Pharmacy (X.L., T.C., Z.C., T.S., F.Z.), Save Sight Institute (L.Z.), and Discipline of Pharmacology (M.M.), Faculty of Medicine and Health, University of Sydney, New South Wales, Australia; and Japanese Foundation for Cancer Research, Koto-ku, Tokyo, Japan (T.C.)
| | - Tahiatul Shams
- School of Pharmacy (X.L., T.C., Z.C., T.S., F.Z.), Save Sight Institute (L.Z.), and Discipline of Pharmacology (M.M.), Faculty of Medicine and Health, University of Sydney, New South Wales, Australia; and Japanese Foundation for Cancer Research, Koto-ku, Tokyo, Japan (T.C.)
| | - Ling Zhu
- School of Pharmacy (X.L., T.C., Z.C., T.S., F.Z.), Save Sight Institute (L.Z.), and Discipline of Pharmacology (M.M.), Faculty of Medicine and Health, University of Sydney, New South Wales, Australia; and Japanese Foundation for Cancer Research, Koto-ku, Tokyo, Japan (T.C.)
| | - Michael Murray
- School of Pharmacy (X.L., T.C., Z.C., T.S., F.Z.), Save Sight Institute (L.Z.), and Discipline of Pharmacology (M.M.), Faculty of Medicine and Health, University of Sydney, New South Wales, Australia; and Japanese Foundation for Cancer Research, Koto-ku, Tokyo, Japan (T.C.)
| | - Fanfan Zhou
- School of Pharmacy (X.L., T.C., Z.C., T.S., F.Z.), Save Sight Institute (L.Z.), and Discipline of Pharmacology (M.M.), Faculty of Medicine and Health, University of Sydney, New South Wales, Australia; and Japanese Foundation for Cancer Research, Koto-ku, Tokyo, Japan (T.C.)
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35
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Giron F, Quigley EMM. Pharmabiotic Manipulation of the Microbiota in Gastrointestinal Disorders: A Clinical Perspective. J Neurogastroenterol Motil 2018; 24:355-366. [PMID: 29684976 PMCID: PMC6034666 DOI: 10.5056/jnm18004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 03/04/2018] [Accepted: 03/26/2018] [Indexed: 12/13/2022] Open
Abstract
The advent and widespread availability of high-throughput technology has revolutionized the assessment of the communities of microorganisms that inhabit the gastrointestinal tract––the gut microbiota. As our understanding of the role of the microbiota in health and human disease increases, so also do efforts to prevent and treat disease through the modulation of the microbiota. Several strategies are available to us and range from time honored approaches, such as antibiotics and probiotics, to changes in diet, the administration of prebiotics as food supplements, and fecal microbiota transplantation. Of these, diet is perhaps the most pervasive but often ignored modulator of the microbiota, and a failure to recognize its impact complicates the interpretation of many microbiota studies. The impacts of antibiotics on the microbiota are more complex than originally thought and, though antibiotics can be life-saving, their effects on commensal bacterial populations can be clinically significant. Though there have been many studies of, and even more claims made for, probiotics, the majority of available studies suffer from significant deficits in study design and execution and many claims remain to be substantiated. Though holding much promise, the study of prebiotics in human disease is still in its infancy. Possibilities other than the administration of live organisms have been identified through efforts to mine the microbiota for novel therapeutics and include: dead organisms, bacterial components, small molecules elaborated by bacteria, and even bacterial DNA. Accordingly, the term pharmabiotic has been introduced to encompass the full range of therapeutic possibilities that the microbiota offers.
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Affiliation(s)
- Fanny Giron
- Gastroenterology and Hepatology, Lynda K and David M Underwood Center for Digestive Disorders, Houston Methodist Hospital and Weill Cornell Medical College, Houston, Texas, USA
| | - Eamonn M M Quigley
- Gastroenterology and Hepatology, Lynda K and David M Underwood Center for Digestive Disorders, Houston Methodist Hospital and Weill Cornell Medical College, Houston, Texas, USA
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36
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Flammini L, Mantelli L, Volpe A, Domenichini G, Di Lecce R, Dondi M, Cantoni AM, Barocelli E, Quintavalla F. Rifaximin anti-inflammatory activity on bovine endometrium primary cell cultures: a preliminary study. Vet Med Sci 2018; 4:326-332. [PMID: 29984902 PMCID: PMC6236135 DOI: 10.1002/vms3.115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Rifaximin is an unabsorbed oral antibiotic showing anti‐inflammatory properties in human pathologies like irritable bowel syndrome and inflammatory bowel disease. In veterinary medicine, rifaximin is primarily used in the treatment of dermatological diseases in all animal species, in therapy and prophylaxis of mastitis in cows and in the treatment of endometritis in cattle and horses. The aim of this preliminary study was to evaluate the anti‐inflammatory properties of rifaximin on primary cell cultures from bovine endometrium in which inflammatory response was induced by Lipopolysaccaride (LPS) treatment. Epithelial and stromal cells were isolated from bovine endometrium and separately incubated for 24 h with 1 μg mL−1LPS after rifaximin (10, 50 and 100 μmol L−1) or dexamethasone (10 μmol L−1) pre‐treatment for 24 h. Supernatants were collected 24 h after LPS treatment and interleukin (IL)‐6 and IL‐8 accumulation was measured by ELISA. Rifaximin (10, 50 and 100 μmol L−1) dose dependently inhibited the LPS‐induced increase in IL‐6 and IL‐8 in stromal cells, whereas in epithelial cells it was not possible to detect any accumulation of these interleukins. Rifaximin reduced IL‐6 and IL‐8 production, showing a potential anti‐inflammatory effect that opens up to new possibilities for the use of this drug in uterine inflammatory diseases.
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Affiliation(s)
- Lisa Flammini
- Food and Drug Department, University of Parma, Parma, Italy
| | - Leonardo Mantelli
- Department of Medical Veterinary Sciences, University of Parma, Parma, Italy
| | | | | | - Rosanna Di Lecce
- Department of Medical Veterinary Sciences, University of Parma, Parma, Italy
| | - Maurizio Dondi
- Department of Medical Veterinary Sciences, University of Parma, Parma, Italy
| | - Anna Maria Cantoni
- Department of Medical Veterinary Sciences, University of Parma, Parma, Italy
| | | | - Fausto Quintavalla
- Department of Medical Veterinary Sciences, University of Parma, Parma, Italy
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Dothel G, Barbaro MR, Raschi E, Barbara G, De Ponti F. Advancements in drug development for diarrhea-predominant irritable bowel syndrome. Expert Opin Investig Drugs 2018; 27:251-263. [PMID: 29451407 DOI: 10.1080/13543784.2018.1442434] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Diarrhea-predominant irritable bowel syndrome (IBS-D) is a common disorder characterized by a complex pathophysiology hampering optimal targeted drug development. Recent advances in our understanding of key underlying mechanisms prompted novel therapeutics including novel pharmacological approaches. AREAS COVERED This review summarizes the latest advancements in the pipeline of IBS-D drugs focusing on new pharmacological targets, efficacy and safety of medicinal products considering the recent harmonization of regulatory requirements by the FDA and the EMA. EXPERT OPINION The new 5-HT3 receptor antagonist ramosetron appears a promising therapeutic approach devoid of significant adverse events, although it is presently unavailable in Western countries, most likely because of the precautionary approach taken by regulatory agencies with this drug class. New pharmacological concepts on full agonists/antagonists, mixed-receptor activity and novel drug targets may streamline the present drug pipeline along with the adherence on new regulatory guidelines on outcome measures. Eluxadoline can be taken as an example of this paradigm shift. It has now been granted marketing authorization for IBS-D on both sides of the Atlantic, but it is still considered as a second-line agent by the NICE. There is still much work to be done to fully cover clinical needs of patients with IBS-D.
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Affiliation(s)
- Giovanni Dothel
- a Department of Medical and Surgical Sciences , University of Bologna , Bologna , Italy
| | | | - Emanuel Raschi
- a Department of Medical and Surgical Sciences , University of Bologna , Bologna , Italy
| | - Giovanni Barbara
- a Department of Medical and Surgical Sciences , University of Bologna , Bologna , Italy
| | - Fabrizio De Ponti
- a Department of Medical and Surgical Sciences , University of Bologna , Bologna , Italy
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38
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Rifaximin decreases virulence of Crohn's disease-associated Escherichia coli and epithelial inflammatory responses. J Antibiot (Tokyo) 2018; 71:485-494. [PMID: 29410518 DOI: 10.1038/s41429-017-0022-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 10/17/2017] [Accepted: 12/21/2017] [Indexed: 12/31/2022]
Abstract
Escherichia coli with an adherent and invasive pathotype (AIEC) is implicated in the pathogenesis of Crohn's disease (CD). Rifaximin improves symptoms in mild-to-moderate CD. It is unclear if this outcome is due to its effects on bacteria or intestinal epithelial inflammatory responses. We examined the effects of rifaximin on the growth and virulence of CD-associated E. coli and intestinal epithelial inflammatory responses. Seven well-characterized CD-associated E. coli strains (six AIEC, one non-AIEC; four rifaximin-resistant, three sensitive) were evaluated. We assessed the effects of rifaximin on CD-associated E. coli growth, adhesion to, and invasion of epithelial cells, virulence gene expression, motility, and survival in macrophages. Additionally, we determined the effects of rifaximin on intestinal epithelial inflammatory responses. In vitro rifaximin exerted a dose-dependent effect on the growth of sensitive strains but did not affect the growth of resistant strains. Rifaximin reduced adhesion, invasion, virulence gene expression and motility of CD-associated E. coli in a manner that was independent of its antimicrobial effect. Furthermore, rifaximin reduced IL-8 secretion from pregnane X receptor-expressing T84 colonic epithelial cells. The effect of rifaximin on adhesion was largely attributable to its action on bacteria, whereas decreases in invasion and cytokine secretion were due to its effect on the epithelium. In conclusion, our results show that rifaximin interferes with multiple steps implicated in host-AIEC interactions related to CD, including adhesion to, and invasion of epithelial cells, virulence gene expression, motility, and pro-inflammatory cytokine secretion. Further study is required to determine the relationship of these effects to clinical responses in CD patients.
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Ponziani FR, Zocco MA, D’Aversa F, Pompili M, Gasbarrini A. Eubiotic properties of rifaximin: Disruption of the traditional concepts in gut microbiota modulation. World J Gastroenterol 2017; 23:4491-4499. [PMID: 28740337 PMCID: PMC5504364 DOI: 10.3748/wjg.v23.i25.4491] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 04/14/2017] [Accepted: 05/19/2017] [Indexed: 02/06/2023] Open
Abstract
Antibiotics are usually prescribed to cure infections but they also have significant modulatory effects on the gut microbiota. Several alterations of the intestinal bacterial community have been reported during antibiotic treatment, including the reduction of beneficial bacteria as well as of microbial alpha-diversity. Although after the discontinuation of antibiotic therapies it has been observed a trend towards the restoration of the original condition, the new steady state is different from the previous one, as if antibiotics induced some kind of irreversible perturbation of the gut microbial community. The poorly absorbed antibiotic rifaximin seem to be different from the other antibiotics, because it exerts non-traditional effects additional to the bactericidal/bacteriostatic activity on the gut microbiota. Rifaximin is able to reduce bacterial virulence and translocation, has anti-inflammatory properties and has been demonstrated to positively modulate the gut microbial composition. Animal models, culture studies and metagenomic analyses have demonstrated an increase in Bifidobacterium, Faecalibacterium prausnitzii and Lactobacillus abundance after rifaximin treatment, probably consequent to the induction of bacterial resistance, with no major change in the overall gut microbiota composition. Antibiotics are therefore modulators of the symbiotic relationship between the host and the gut microbiota. Specific antibiotics, such as rifaximin, can also induce eubiotic changes in the intestinal ecosystem; this additional property may represent a therapeutic advantage in specific clinical settings.
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40
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Seow CL, Lau AJ. Differential activation of pregnane X receptor by carnosic acid, carnosol, ursolic acid, and rosmarinic acid. Pharmacol Res 2017; 120:23-33. [PMID: 28288941 DOI: 10.1016/j.phrs.2017.03.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 02/24/2017] [Accepted: 03/08/2017] [Indexed: 10/20/2022]
Abstract
Pregnane X receptor (PXR) regulates the expression of many genes, including those involved in drug metabolism and transport, and has been linked to various diseases, including inflammatory bowel disease. In the present study, we determined whether carnosic acid and other chemicals in rosemary extract (carnosol, ursolic acid, and rosmarinic acid) are PXR activators. As assessed in dual-luciferase reporter gene assays, carnosic acid, carnosol, and ursolic acid, but not rosmarinic acid, activated human PXR (hPXR) and mouse PXR (mPXR), whereas carnosol and ursolic acid, but not carnosic acid or rosmarinic acid, activated rat PXR (rPXR). Dose-response experiments indicated that carnosic acid, carnosol, and ursolic acid activated hPXR with EC50 values of 0.79, 2.22, and 10.77μM, respectively. Carnosic acid, carnosol, and ursolic acid, but not rosmarinic acid, transactivated the ligand-binding domain of hPXR and recruited steroid receptor coactivator-1 (SRC-1), SRC-2, and SRC-3 to the ligand-binding domain of hPXR. Carnosic acid, carnosol, and ursolic acid, but not rosmarinic acid, increased hPXR target gene expression, as shown by an increase in CYP3A4, UGT1A3, and ABCB1 mRNA expression in LS180 human colon adenocarcinoma cells. Rosmarinic acid did not attenuate the extent of hPXR activation by rifampicin, suggesting it is not an antagonist of hPXR. Overall, carnosic acid, carnosol, and ursolic acid, but not rosmarinic acid, are hPXR agonists, and carnosic acid shows species-dependent activation of hPXR and mPXR, but not rPXR. The findings provide new mechanistic insight on the effects of carnosic acid, carnosol, and ursolic acid on PXR-mediated biological effects.
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Affiliation(s)
- Chun Ling Seow
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Aik Jiang Lau
- Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore; Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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Cuomo R, Barbara G, Annibale B. Rifaximin and diverticular disease: Position paper of the Italian Society of Gastroenterology (SIGE). Dig Liver Dis 2017; 49:595-603. [PMID: 28215517 DOI: 10.1016/j.dld.2017.01.164] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 01/19/2017] [Accepted: 01/23/2017] [Indexed: 02/08/2023]
Abstract
Management of diverticular disease has significantly improved in the last decade. Antibiotic treatment is used for symptom relief and prevention of complications. In Italy, the non-absorbable antibiotic rifaximin is one of the most frequently used drugs, and it is perceived as the reference drug to treat symptomatic diverticular disease. Its non-systemic absorption and high faecal concentrations have oriented rifaximin use to the gastrointestinal tract, where rifaximin exerts eubiotic effects representing an additional value to its antibiotic activity. This position paper was commissioned by the Italian Society of Gastroenterology governing board for a panel of experts (RC, GB, BA) to highlight the indications for treatment of diverticular disease. There is a lack of rationale for drug use for the primary prevention of diverticulitis in patients with diverticulosis; thus, rifaximin use should be avoided. The cyclic use of rifaximin, in association with high-fibre intake, is safe and useful for the treatment of symptomatic uncomplicated diverticular disease, even if the cost-efficacy of long-term treatment remains to be determined. The use of rifaximin in the prevention of diverticulitis recurrence is promising, but the low therapeutic advantage needs to be verified. No evidence is available on the efficacy of rifaximin treatment on acute uncomplicated diverticulitis.
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Affiliation(s)
- Rosario Cuomo
- Department of Clinical Medicine and Surgery, Federico II University, Napoli, Italy
| | - Giovanni Barbara
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Bruno Annibale
- Medical-Surgical Science and Translational Medicine Department, Sapienza University, Rome, Italy.
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Menozzi A, Dall'Aglio M, Quintavalla F, Dallavalle L, Meucci V, Bertini S. Rifaximin is an effective alternative to metronidazole for the treatment of chronic enteropathy in dogs: a randomised trial. BMC Vet Res 2016; 12:217. [PMID: 27716258 PMCID: PMC5053129 DOI: 10.1186/s12917-016-0851-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 10/01/2016] [Indexed: 12/13/2022] Open
Abstract
Background A clinical trial was conducted in order to assess the efficacy of rifaximin, a broad-spectrum antibiotic with negligible gastrointestinal absorption, in comparison with metronidazole, a commonly employed antimicrobial drug, in dogs with chronic enteropathy. Twenty-four pet dogs were randomly enrolled into two different groups: MET group (10 dogs) and RIF group (14 dogs). Dogs of MET group received metronidazole 15 mg/kg q12h for 21 days by oral route, whereas dogs of RIF group, were given rifaximin 25 mg/kg q12h for 21 days by oral route. Clinical signs of disease were evaluated the day before the beginning of drug administration (D0), and at the end of treatment (D21), by means of Canine IBD Activity Index (CIBDAI). Blood levels of C-reactive protein (CRP) at D0 and D21 were also measured, as another parameter of treatment efficacy. The primary outcome measure of efficacy was the complete remission at D21, defined as a 75 % or greater decrease of CIBDAI; secondary outcome measures were the variation of mean CIBDAI scores, of mean CRP serum levels, and any observed adverse effect from D0 to D21. Results Treatment with metronidazole or rifaximin greatly improved the clinical signs of disease in each group: in MET group the complete remission was achieved in 8 of 10 dogs (80.0 %), and partial remission in 2 subjects (20.0 %). In RIF group, 12 of 14 dogs showed complete remission (85.7 %), and the remaining 2 dogs were in partial remission (14.3 %). There were also significant decreases of CIBDAI scores (P = 0.002 and P = 0.0002 for MET and RIF, respectively), and CRP levels (P = 0.002 and P = 0.0001 for MET and RIF, respectively) compared to pre-treatment values in both groups. No significant difference, however, was found when comparing MET and RIF groups. No relevant side-effect was reported during the trial with either drugs. Conclusions The present study showed, for the first time, that oral rifaximin could represent an effective alternative to metronidazole for the induction of clinical remission in dogs with chronic enteropathy. Electronic supplementary material The online version of this article (doi:10.1186/s12917-016-0851-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alessandro Menozzi
- Department of Veterinary Science, University of Parma, Strada Del Taglio 10, 43126, Parma, Italy.
| | | | - Fausto Quintavalla
- Department of Veterinary Science, University of Parma, Strada Del Taglio 10, 43126, Parma, Italy
| | - Luca Dallavalle
- ATI Pets Srl, Fatro Group SpA, Ozzano dell'Emilia, Bologna, Italy
| | - Valentina Meucci
- Department of Veterinary Science, University of Pisa, Pisa, Italy
| | - Simone Bertini
- Department of Veterinary Science, University of Parma, Strada Del Taglio 10, 43126, Parma, Italy
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Chai SC, Cherian MT, Wang YM, Chen T. Small-molecule modulators of PXR and CAR. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1859:1141-1154. [PMID: 26921498 PMCID: PMC4975625 DOI: 10.1016/j.bbagrm.2016.02.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/06/2016] [Accepted: 02/06/2016] [Indexed: 12/27/2022]
Abstract
Two nuclear receptors, the pregnane X receptor (PXR) and the constitutive androstane receptor (CAR), participate in the xenobiotic detoxification system by regulating the expression of drug-metabolizing enzymes and transporters in order to degrade and excrete foreign chemicals or endogenous metabolites. This review aims to expand the perceived relevance of PXR and CAR beyond their established role as master xenosensors to disease-oriented areas, emphasizing their modulation by small molecules. Structural studies of these receptors have provided much-needed insight into the nature of their binding promiscuity and the important elements that lead to ligand binding. Reports of species- and isoform-selective activation highlight the need for further scrutiny when extrapolating from animal data to humans, as animal models are at the forefront of early drug discovery. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie.
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Affiliation(s)
- Sergio C Chai
- Department of Chemical Biology and Therapeutics, 262 Danny Thomas Place, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Milu T Cherian
- Department of Chemical Biology and Therapeutics, 262 Danny Thomas Place, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Yue-Ming Wang
- Department of Chemical Biology and Therapeutics, 262 Danny Thomas Place, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, 262 Danny Thomas Place, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
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Kang DJ, Kakiyama G, Betrapally NS, Herzog J, Nittono H, Hylemon PB, Zhou H, Carroll I, Yang J, Gillevet PM, Jiao C, Takei H, Pandak WM, Iida T, Heuman DM, Fan S, Fiehn O, Kurosawa T, Sikaroodi M, Sartor RB, Bajaj JS. Rifaximin Exerts Beneficial Effects Independent of its Ability to Alter Microbiota Composition. Clin Transl Gastroenterol 2016; 7:e187. [PMID: 27560928 PMCID: PMC5543406 DOI: 10.1038/ctg.2016.44] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 07/15/2016] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVES Rifaximin has clinical benefits in minimal hepatic encephalopathy (MHE) but the mechanism of action is unclear. The antibiotic-dependent and -independent effects of rifaximin need to be elucidated in the setting of MHE-associated microbiota. To assess the action of rifaximin on intestinal barrier, inflammatory milieu and ammonia generation independent of microbiota using rifaximin. METHODS Four germ-free (GF) mice groups were used (1) GF, (2) GF+rifaximin, (3) Humanized with stools from an MHE patient, and (4) Humanized+rifaximin. Mice were followed for 30 days while rifaximin was administered in chow at 100 mg/kg from days 16-30. We tested for ammonia generation (small-intestinal glutaminase, serum ammonia, and cecal glutamine/amino-acid moieties), systemic inflammation (serum IL-1β, IL-6), intestinal barrier (FITC-dextran, large-/small-intestinal expression of IL-1β, IL-6, MCP-1, e-cadherin and zonulin) along with microbiota composition (colonic and fecal multi-tagged sequencing) and function (endotoxemia, fecal bile acid deconjugation and de-hydroxylation). RESULTS All mice survived until day 30. In the GF setting, rifaximin decreased intestinal ammonia generation (lower serum ammonia, increased small-intestinal glutaminase, and cecal glutamine content) without changing inflammation or intestinal barrier function. Humanized microbiota increased systemic/intestinal inflammation and endotoxemia without hyperammonemia. Rifaximin therapy significantly ameliorated these inflammatory cytokines. Rifaximin also favorably impacted microbiota function (reduced endotoxin and decreased deconjugation and formation of potentially toxic secondary bile acids), but not microbial composition in humanized mice. CONCLUSIONS Rifaximin beneficially alters intestinal ammonia generation by regulating intestinal glutaminase expression independent of gut microbiota. MHE-associated fecal colonization results in intestinal and systemic inflammation in GF mice, which is also ameliorated with rifaximin.
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Affiliation(s)
- Dae J Kang
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia, USA
| | - Genta Kakiyama
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia, USA
| | - Naga S Betrapally
- Microbiome Analysis Center, George Mason University, Manassas, Virginia, USA
| | - Jeremy Herzog
- Department of Medicine, University of North Carolina, Division of Gastroenterology and Hepatology, Chapel Hill, North Carolina, USA
| | | | - Phillip B Hylemon
- Department of Microbiology and Immunology, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia, USA
| | - Huiping Zhou
- Department of Microbiology and Immunology, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia, USA
| | - Ian Carroll
- Microbiome Analysis Center, George Mason University, Manassas, Virginia, USA
| | - Jing Yang
- Department of Microbiology and Immunology, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia, USA
| | - Patrick M Gillevet
- Microbiome Analysis Center, George Mason University, Manassas, Virginia, USA
| | - Chunhua Jiao
- Department of Microbiology and Immunology, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia, USA
| | - Hajime Takei
- Junshin Clinic Bile Acid Institute, Tokyo, Japan
| | - William M Pandak
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia, USA
| | - Takashi Iida
- Department of Chemistry, College of Humanities and Sciences, Nihon University, Tokyo, Japan
| | - Douglas M Heuman
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia, USA
| | - Sili Fan
- West Coast Metabolomics Center, University of California, Davis, California, USA
| | - Oliver Fiehn
- West Coast Metabolomics Center, University of California, Davis, California, USA
| | - Takao Kurosawa
- School of Pharmaceutical Science, Health Sciences University of Hokkaido, Tobetsu, Japan
| | - Masoumeh Sikaroodi
- Microbiome Analysis Center, George Mason University, Manassas, Virginia, USA
| | - R B Sartor
- Department of Medicine, University of North Carolina, Division of Gastroenterology and Hepatology, Chapel Hill, North Carolina, USA
| | - Jasmohan S Bajaj
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia, USA
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Garg A, Zhao A, Erickson SL, Mukherjee S, Lau AJ, Alston L, Chang TKH, Mani S, Hirota SA. Pregnane X Receptor Activation Attenuates Inflammation-Associated Intestinal Epithelial Barrier Dysfunction by Inhibiting Cytokine-Induced Myosin Light-Chain Kinase Expression and c-Jun N-Terminal Kinase 1/2 Activation. J Pharmacol Exp Ther 2016; 359:91-101. [PMID: 27440420 DOI: 10.1124/jpet.116.234096] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 07/19/2016] [Indexed: 02/06/2023] Open
Abstract
The inflammatory bowel diseases (IBDs) are chronic inflammatory disorders with a complex etiology. IBD is thought to arise in genetically susceptible individuals in the context of aberrant interactions with the intestinal microbiota and other environmental risk factors. Recently, the pregnane X receptor (PXR) was identified as a sensor for microbial metabolites, whose activation can regulate the intestinal epithelial barrier. Mutations in NR1I2, the gene that encodes the PXR, have been linked to IBD, and in animal models, PXR deletion leads to barrier dysfunction. In the current study, we sought to assess the mechanism(s) through which the PXR regulates barrier function during inflammation. In Caco-2 intestinal epithelial cell monolayers, tumor necrosis factor-α/interferon-γ exposure disrupted the barrier and triggered zonula occludens-1 relocalization, increased expression of myosin light-chain kinase (MLCK), and activation of c-Jun N-terminal kinase 1/2 (JNK1/2). Activation of the PXR [rifaximin and [[3,5-Bis(1,1-dimethylethyl)-4-hydroxyphenyl]ethenylidene]bis-phosphonic acid tetraethyl ester (SR12813); 10 μM] protected the barrier, an effect that was associated with attenuated MLCK expression and JNK1/2 activation. In vivo, activation of the PXR [pregnenolone 16α-carbonitrile (PCN)] attenuated barrier disruption induced by toll-like receptor 4 activation in wild-type, but not Pxr-/-, mice. Furthermore, PCN treatment protected the barrier in the dextran-sulfate sodium model of experimental colitis, an effect that was associated with reduced expression of mucosal MLCK and phosphorylated JNK1/2. Together, our data suggest that the PXR regulates the intestinal epithelial barrier during inflammation by modulating cytokine-induced MLCK expression and JNK1/2 activation. Thus, targeting the PXR may prove beneficial for the treatment of inflammation-associated barrier disruption in the context of IBD.
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Affiliation(s)
- Aditya Garg
- Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.)
| | - Angela Zhao
- Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.)
| | - Sarah L Erickson
- Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.)
| | - Subhajit Mukherjee
- Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.)
| | - Aik Jiang Lau
- Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.)
| | - Laurie Alston
- Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.)
| | - Thomas K H Chang
- Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.)
| | - Sridhar Mani
- Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.)
| | - Simon A Hirota
- Department of Physiology and Pharmacology (A.G., A.Z., S.L.E., L.A., S.A.H.), and Department of Microbiology, Immunology and Infectious Diseases (S.A.H.), University of Calgary, Calgary, Alberta, Canada; Department of Medicine, Albert Einstein College of Medicine, Bronx, New York (Su.M., Sr.M.); and Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada (A.J.L., T.K.H.C.)
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Abstract
Rifamycins inhibit RNA polymerase of most bacterial genera. Rifampicin remains part of combination therapy for treating tuberculosis (TB), and for treating Gram-positive prosthetic joint and valve infections, in which biofilms are prominent. Rifabutin has use for AIDS patients in treating mycobacterial infections TB and Mycobacterium avium complex (MAC), having fewer drug-drug interactions that interfere with AIDS medications. Rifabutin is occasionally used in combination to eradicate Helicobacter pylori (peptic ulcer disease). Rifapentine has yet to fulfill its potential in reducing time of treatment for TB. Rifaximin is a monotherapeutic agent to treat gastrointestinal (GI) disorders, such as hepatic encephalopathy, irritable bowel syndrome, and travelers' diarrhea. Rifaximin is confined to the GI tract because it is not systemically absorbed on oral dosing, achieving high local concentrations, and showing anti-inflammatory properties in addition to its antibacterial activity. Resistance issues are unavoidable with all the rifamycins when the bioburden is high, because of mutations that modify RNA polymerase.
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Esposito G, Nobile N, Gigli S, Seguella L, Pesce M, d’Alessandro A, Bruzzese E, Capoccia E, Steardo L, Cuomo R, Sarnelli G. Rifaximin Improves Clostridium difficile Toxin A-Induced Toxicity in Caco-2 Cells by the PXR-Dependent TLR4/MyD88/NF-κB Pathway. Front Pharmacol 2016; 7:120. [PMID: 27242527 PMCID: PMC4860461 DOI: 10.3389/fphar.2016.00120] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 04/25/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Clostridium difficile infections (CDIs) caused by Clostridium difficile toxin A (TcdA) lead to severe ulceration, inflammation and bleeding of the colon, and are difficult to treat. AIM The study aimed to evaluate the effect of rifaximin on TcdA-induced apoptosis in intestinal epithelial cells and investigate the role of PXR in its mechanism of action. METHODS Caco-2 cells were incubated with TcdA and treated with rifaximin (0.1-10 μM) with or without ketoconazole (10 μM). The transepithelial electrical resistance (TEER) and viability of the treated cells was determined. Also, the expression of zona occludens-1 (ZO-1), toll-like receptor 4 (TLR4), Bcl-2-associated X protein (Bax), transforming growth factor-β-activated kinase-1 (TAK1), myeloid differentiation factor 88 (MyD88), and nuclear factor-kappaB (NF-κB) was determined. RESULTS Rifaximin treatment (0.1, 1.0, and 10 μM) caused a significant and concentration-dependent increase in the TEER of Caco-2 cells (360, 480, and 680% vs. TcdA treatment) 24 h after the treatment and improved their viability (61, 79, and 105%). Treatment also concentration-dependently decreased the expression of Bax protein (-29, -65, and -77%) and increased the expression of ZO-1 (25, 54, and 87%) and occludin (71, 114, and 262%) versus TcdA treatment. The expression of TLR4 (-33, -50, and -75%), MyD88 (-29, -60, and -81%) and TAK1 (-37, -63, and -79%) were also reduced with rifaximin versus TcdA treatment. Ketoconazole treatment inhibited these effects. CONCLUSION Rifaximin improved TcdA-induced toxicity in Caco-2 cells by the PXR-dependent TLR4/MyD88/NF-κB pathway mechanism, and may be useful in the treatment of CDIs.
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Affiliation(s)
- Giuseppe Esposito
- Department of Physiology and Pharmacology “Vittorio Erspamer”, Sapienza University of RomeRome, Italy
| | - Nicola Nobile
- Department of Physiology and Pharmacology “Vittorio Erspamer”, Sapienza University of RomeRome, Italy
| | - Stefano Gigli
- Department of Physiology and Pharmacology “Vittorio Erspamer”, Sapienza University of RomeRome, Italy
| | - Luisa Seguella
- Department of Physiology and Pharmacology “Vittorio Erspamer”, Sapienza University of RomeRome, Italy
| | - Marcella Pesce
- Department of Clinical Medicine and Surgery, University of Naples Federico IINaples, Italy
| | | | - Eugenia Bruzzese
- Department of Translational Medical Science, University of Naples Federico IINaples, Italy
| | - Elena Capoccia
- Department of Physiology and Pharmacology “Vittorio Erspamer”, Sapienza University of RomeRome, Italy
| | - Luca Steardo
- Department of Physiology and Pharmacology “Vittorio Erspamer”, Sapienza University of RomeRome, Italy
| | - Rosario Cuomo
- Department of Clinical Medicine and Surgery, University of Naples Federico IINaples, Italy
| | - Giovanni Sarnelli
- Department of Clinical Medicine and Surgery, University of Naples Federico IINaples, Italy
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Shakhnovich V, Vyhlidal C, Friesen C, Hildreth A, Singh V, Daniel J, Kearns GL, Leeder JS. Decreased Pregnane X Receptor Expression in Children with Active Crohn's Disease. ACTA ACUST UNITED AC 2016; 44:1066-9. [PMID: 27013401 PMCID: PMC4931888 DOI: 10.1124/dmd.115.068742] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 03/22/2016] [Indexed: 01/02/2023]
Abstract
Expression of the pregnane X receptor (PXR) has been reported to be decreased in animal models of inflammatory bowel disease (IBD). To investigate the differential expression of PXR in children with Crohn’s disease, a type of IBD, RNA was extracted from archived intestinal biopsies from 18 children with Crohn’s disease (CD) and 12 age- and sex-matched controls (aged 7–17yrs). The aim of this investigation was to compare the relative mRNA expression of PXR, cytochrome p450 3A4 (CYP3A4), and villin 1 (VIL1) (a marker of epithelial cell integrity) in the inflamed terminal ileum (TI) versus noninflamed duodenum of children with CD. Relative expression was determined via reverse transcription real-time quantitative polymerase chain reaction, data normalized to glyceraldehyde 3-phosphate dehydrogenase, and differences in gene expression explored via paired t tests. PXR expression was decreased in the inflamed TI versus noninflamed duodenum (TI = 1.88 ± 0.89 versus duodenum = 2.5 ± 0.67; P < 0.001) in CD, but not controls (TI = 2.11 ± 0.41 versus duodenum = 2.26 ± 0.61; P = 0.52). CYP3A4 expression was decreased in CD (TI = –0.89 ± 3.11 versus duodenum = 1.90 ± 2.29; P < 0.05), but not controls (TI = 2.46 ± 0.51 versus duodenum = 2.60 ± 0.60; P = 0.61), as was VIL1 (CD TI = 3.80 ± 0.94 versus duodenum = 4.61 ± 0.52; P < 0.001; controls TI = 4.30 ± 0.35 versus duodenum = 4.47 ± 0.40; P = 0.29). PXR expression correlated with VIL1 (r = 0.78, P = 0.01) and CYP3A4 (r = 0.52, P = 0.01) expression. In conclusion, PXR, CYP3A4, and VIL1 expression was decreased only in the actively inflamed small intestinal tissue in children with CD. Our findings suggest that inflammation has the potential to influence expression of genes, and potentially intestinal proteins, important to drug disposition and response. The observed differential patterns of gene expression support further investigation of the role of PXR in the pathogenesis and/or treatment of pediatric Crohn’s disease.
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Affiliation(s)
- Valentina Shakhnovich
- The Children's Mercy Hospital, Kansas City, Missouri (V.S., C.V., C.F., V.S., J.D., J.S.L.) University of California San Diego, San Diego, California (A.H.); Arkansas Children's Hospital Research Institute, Little Rock, Arkansas (G.L.K.). Laboratory of origin: The Children's Mercy Hospital
| | - Carrie Vyhlidal
- The Children's Mercy Hospital, Kansas City, Missouri (V.S., C.V., C.F., V.S., J.D., J.S.L.) University of California San Diego, San Diego, California (A.H.); Arkansas Children's Hospital Research Institute, Little Rock, Arkansas (G.L.K.). Laboratory of origin: The Children's Mercy Hospital
| | - Craig Friesen
- The Children's Mercy Hospital, Kansas City, Missouri (V.S., C.V., C.F., V.S., J.D., J.S.L.) University of California San Diego, San Diego, California (A.H.); Arkansas Children's Hospital Research Institute, Little Rock, Arkansas (G.L.K.). Laboratory of origin: The Children's Mercy Hospital
| | - Amber Hildreth
- The Children's Mercy Hospital, Kansas City, Missouri (V.S., C.V., C.F., V.S., J.D., J.S.L.) University of California San Diego, San Diego, California (A.H.); Arkansas Children's Hospital Research Institute, Little Rock, Arkansas (G.L.K.). Laboratory of origin: The Children's Mercy Hospital
| | - Vivekanand Singh
- The Children's Mercy Hospital, Kansas City, Missouri (V.S., C.V., C.F., V.S., J.D., J.S.L.) University of California San Diego, San Diego, California (A.H.); Arkansas Children's Hospital Research Institute, Little Rock, Arkansas (G.L.K.). Laboratory of origin: The Children's Mercy Hospital
| | - James Daniel
- The Children's Mercy Hospital, Kansas City, Missouri (V.S., C.V., C.F., V.S., J.D., J.S.L.) University of California San Diego, San Diego, California (A.H.); Arkansas Children's Hospital Research Institute, Little Rock, Arkansas (G.L.K.). Laboratory of origin: The Children's Mercy Hospital
| | - Gregory L Kearns
- The Children's Mercy Hospital, Kansas City, Missouri (V.S., C.V., C.F., V.S., J.D., J.S.L.) University of California San Diego, San Diego, California (A.H.); Arkansas Children's Hospital Research Institute, Little Rock, Arkansas (G.L.K.). Laboratory of origin: The Children's Mercy Hospital
| | - J Steven Leeder
- The Children's Mercy Hospital, Kansas City, Missouri (V.S., C.V., C.F., V.S., J.D., J.S.L.) University of California San Diego, San Diego, California (A.H.); Arkansas Children's Hospital Research Institute, Little Rock, Arkansas (G.L.K.). Laboratory of origin: The Children's Mercy Hospital
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Zhou C. Novel functions of PXR in cardiometabolic disease. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:1112-1120. [PMID: 26924429 DOI: 10.1016/j.bbagrm.2016.02.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 12/17/2022]
Abstract
Cardiometabolic disease emerges as a worldwide epidemic and there is urgent need to understand the molecular mechanisms underlying this chronic disease. The chemical environment to which we are exposed has significantly changed in the past few decades and recent research has implicated its contribution to the development of many chronic human diseases. However, the mechanisms of how exposure to chemicals contributes to the development of cardiometabolic disease are poorly understood. Numerous chemicals have been identified as ligands for the pregnane X receptor (PXR), a nuclear receptor functioning as a xenobiotic sensor to coordinately regulate xenobiotic metabolism via transcriptional regulation of xenobiotic-detoxifying enzymes and transporters. In the past decade, the function of PXR in the regulation of xenobiotic metabolism has been extensively studied by many laboratories and the role of PXR as a xenobiotic sensor has been well-established. The identification of PXR as a xenobiotic sensor has provided an important tool for the study of new mechanisms through which xenobiotic exposure impacts human chronic diseases. Recent studies have revealed novel and unexpected roles of PXR in modulating obesity, insulin sensitivity, lipid homeostasis, atherogenesis, and vascular functions. These studies suggest that PXR signaling may contribute significantly to the pathophysiological effects of many known xenobiotics on cardiometabolic disease in humans. The discovery of novel functions of PXR in cardiometabolic disease not only contributes to our understanding of "gene-environment interactions" in predisposing individuals to chronic diseases but also provides strong evidence to inform future risk assessment for relevant chemicals. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie.
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Affiliation(s)
- Changcheng Zhou
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY 40536, USA; Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY 40536, USA.
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Sartor RB. Review article: the potential mechanisms of action of rifaximin in the management of inflammatory bowel diseases. Aliment Pharmacol Ther 2016; 43 Suppl 1:27-36. [PMID: 26618923 DOI: 10.1111/apt.13436] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 04/27/2015] [Accepted: 08/28/2015] [Indexed: 12/14/2022]
Abstract
BACKGROUND Gut microbiota dysbiosis contributes to the pathogenesis of inflammatory bowel diseases (IBD). Although the microbiota's role in IBD pathogenesis, specifically Crohn's disease (CD), provides a rationale for antibiotic treatment, antibiotic use in CD remains controversial. Rifaximin, traditionally identified as a nonsystemic bactericidal antibiotic, may be therapeutically beneficial for inducing CD remission. AIM To examine the role of rifaximin in the management of IBD and its potential mechanisms of action. METHODS A literature search using the following strategy: ('inflammatory bowel disease' OR 'Crohn's' OR 'ulcerative'), 'rifaximin' AND ('barrier' OR 'translocation' OR 'adhesion' OR 'internalization' OR 'pregnane X'), AND 'pregnane X' AND ('Crohn's' OR 'ulcerative colitis' OR 'inflammatory bowel disease'). RESULTS In vitro data suggest rifaximin mediates changes in epithelial cell physiology and reduces bacterial attachment and internalisation. In experimental colitis models, rifaximin antagonised the effects of tumour necrosis factor-α on intestinal epithelial cells by activating pregnane X receptor, which inhibits nuclear factor-κB-mediated proinflammatory mediators and induces detoxification genes (e.g. multidrug resistance 1 and cytochrome P450 3A4). Rifaximin also inhibits bacterial translocation into the mesenteric lymph nodes. CONCLUSION Accumulating evidence suggests that mechanisms of action of rifaximin in IBD may not be limited to direct bactericidal activity; therefore, rifaximin could potentially be redefined as a gut environment modulator.
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Affiliation(s)
- R B Sartor
- Center for Gastrointestinal Biology and Disease, Department of Medicine, Microbiology and Immunology, University of North Carolina, Chapel Hill, NC, USA
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