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Opitz CA, Holfelder P, Prentzell MT, Trump S. The complex biology of aryl hydrocarbon receptor activation in cancer and beyond. Biochem Pharmacol 2023; 216:115798. [PMID: 37696456 PMCID: PMC10570930 DOI: 10.1016/j.bcp.2023.115798] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 09/08/2023] [Accepted: 09/08/2023] [Indexed: 09/13/2023]
Abstract
The aryl hydrocarbon receptor (AHR) signaling pathway is a complex regulatory network that plays a critical role in various biological processes, including cellular metabolism, development, and immune responses. The complexity of AHR signaling arises from multiple factors, including the diverse ligands that activate the receptor, the expression level of AHR itself, and its interaction with the AHR nuclear translocator (ARNT). Additionally, the AHR crosstalks with the AHR repressor (AHRR) or other transcription factors and signaling pathways and it can also mediate non-genomic effects. Finally, posttranslational modifications of the AHR and its interaction partners, epigenetic regulation of AHR and its target genes, as well as AHR-mediated induction of enzymes that degrade AHR-activating ligands may contribute to the context-specificity of AHR activation. Understanding the complexity of AHR signaling is crucial for deciphering its physiological and pathological roles and developing therapeutic strategies targeting this pathway. Ongoing research continues to unravel the intricacies of AHR signaling, shedding light on the regulatory mechanisms controlling its diverse functions.
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Affiliation(s)
- Christiane A Opitz
- German Cancer Research Center (DKFZ), Heidelberg, Division of Metabolic Crosstalk in Cancer and the German Cancer Consortium (DKTK), DKFZ Core Center Heidelberg, 69120 Heidelberg, Germany; Neurology Clinic and National Center for Tumor Diseases, 69120 Heidelberg, Germany.
| | - Pauline Holfelder
- German Cancer Research Center (DKFZ), Heidelberg, Division of Metabolic Crosstalk in Cancer and the German Cancer Consortium (DKTK), DKFZ Core Center Heidelberg, 69120 Heidelberg, Germany; Faculty of Bioscience, Heidelberg University, 69120 Heidelberg, Germany
| | - Mirja Tamara Prentzell
- German Cancer Research Center (DKFZ), Heidelberg, Division of Metabolic Crosstalk in Cancer and the German Cancer Consortium (DKTK), DKFZ Core Center Heidelberg, 69120 Heidelberg, Germany; Faculty of Bioscience, Heidelberg University, 69120 Heidelberg, Germany
| | - Saskia Trump
- Molecular Epidemiology Unit, Berlin Institute of Health at Charité and the German Cancer Consortium (DKTK), Partner Site Berlin, a partnership between DKFZ and Charité -Universitätsmedizin Berlin, 10117 Berlin, Germany
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Lee JY, Ma HW, Kim JH, Park IS, Son M, Ryu KH, Shin J, Kim SW, Cheon JH. Novel Histone Deacetylase 6 Inhibitor Confers Anti-inflammatory Effects and Enhances Gut Barrier Function. Gut Liver 2023; 17:766-776. [PMID: 36167345 PMCID: PMC10502503 DOI: 10.5009/gnl220159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 07/07/2022] [Accepted: 07/18/2022] [Indexed: 11/04/2022] Open
Abstract
Background/Aims The purpose of the current study was to examine the anti-inflammatory effects of CKD-506, a novel histone deacetylase 6 inhibitor, on human peripheral blood mononuclear cells (PBMCs) and CD4+ T cells and to explore the relationship between CKD-506 and gut epithelial barrier function. Methods Lipopolysaccharide-stimulated human PBMCs from inflammatory bowel disease (IBD) patients were treated with CKD-506, and tumor necrosis factor (TNF)-α expression was measured using an enzyme-linked immunosorbent assay. The proliferation of CD4+ T cells from IBD patients was evaluated using flow cytometric analysis. The effects of CKD-506 on gut barrier function in a cell line and colon organoids, based on examinations of mRNA production, goblet cell differentiation, and E-cadherin recovery, were investigated using quantitative reverse transcription polymerase chain reaction, immunofluorescence, and a fluorescein isothiocyanate-dextran permeability assay. Results Secretion of TNF-α, a pivotal pro-inflammatory mediator in IBD, by lipopolysaccharide-triggered PBMCs was markedly decreased by CKD-506 treatment in a dose-dependent manner and to a greater extent than by tofacitinib or tubastatin A treatment. E-cadherin mRNA expression and goblet cell differentiation increased significantly and dose-dependently in HT-29 cells in response to CKD-506, and inhibition of E-cadherin loss after TNF-α stimulation was significantly reduced both in HT-29 cells and gut organoids. Caco-2 cells treated with CKD-506 showed a significant reduction in barrier permeability in a dose-dependent manner. Conclusions The present study demonstrated that CKD-506 has anti-inflammatory effects on PBMCs and CD4 T cells and improves gut barrier function, suggesting its potential as a small-molecule therapeutic option for IBD.
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Affiliation(s)
- Jae-Young Lee
- Department of Medicine, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Korea
| | - Hyun Woo Ma
- Department of Internal Medicine and Institute of Gastroenterology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Korea
| | - Ji Hyung Kim
- Department of Internal Medicine and Institute of Gastroenterology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Korea
| | - I Seul Park
- Department of Internal Medicine and Institute of Gastroenterology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Korea
| | - Mijeong Son
- Department of Internal Medicine and Institute of Gastroenterology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Korea
| | - Keun Ho Ryu
- Department of Non-Clinical Study, CKD Research Institute, CKD Pharmaceutical Co., Yongin, Korea
| | - Jieun Shin
- Department of Non-Clinical Study, CKD Research Institute, CKD Pharmaceutical Co., Yongin, Korea
| | - Seung Won Kim
- Department of Internal Medicine and Institute of Gastroenterology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Korea
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Jae Hee Cheon
- Department of Internal Medicine and Institute of Gastroenterology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, Korea
- Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
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Dothel G, Barbaro MR, Di Vito A, Ravegnini G, Gorini F, Monesmith S, Coschina E, Benuzzi E, Fuschi D, Palombo M, Bonomini F, Morroni F, Hrelia P, Barbara G, Angelini S. New insights into irritable bowel syndrome pathophysiological mechanisms: contribution of epigenetics. J Gastroenterol 2023; 58:605-621. [PMID: 37160449 PMCID: PMC10307698 DOI: 10.1007/s00535-023-01997-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 04/19/2023] [Indexed: 05/11/2023]
Abstract
Irritable bowel syndrome (IBS) is a complex multifactorial condition including alterations of the gut-brain axis, intestinal permeability, mucosal neuro-immune interactions, and microbiota imbalance. Recent advances proposed epigenetic factors as possible regulators of several mechanisms involved in IBS pathophysiology. These epigenetic factors include biomolecular mechanisms inducing chromosome-related and heritable changes in gene expression regardless of DNA coding sequence. Accordingly, altered gut microbiota may increase the production of metabolites such as sodium butyrate, a prominent inhibitor of histone deacetylases. Patients with IBS showed an increased amount of butyrate-producing microbial phila as well as an altered profile of methylated genes and micro-RNAs (miRNAs). Importantly, gene acetylation as well as specific miRNA profiles are involved in different IBS mechanisms and may be applied for future diagnostic purposes, especially to detect increased gut permeability and visceromotor dysfunctions. In this review, we summarize current knowledge of the role of epigenetics in IBS pathophysiology.
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Affiliation(s)
- Giovanni Dothel
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
- Connect By Circular Lab SRL, Madrid, Spain
| | | | - Aldo Di Vito
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Gloria Ravegnini
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Francesca Gorini
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Sarah Monesmith
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Emma Coschina
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Eva Benuzzi
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Daniele Fuschi
- IRCCS Azienda Ospedaliero-Universitaria Di Bologna, Bologna, Italy
| | - Marta Palombo
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Francesca Bonomini
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Fabiana Morroni
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Patrizia Hrelia
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy.
| | - Giovanni Barbara
- IRCCS Azienda Ospedaliero-Universitaria Di Bologna, Bologna, Italy
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Sabrina Angelini
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
- Inter-Departmental Center for Health Sciences & Technologies, CIRI-SDV, University of Bologna, Bologna, Italy
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Sládeková L, Mani S, Dvořák Z. Ligands and agonists of the aryl hydrocarbon receptor AhR: Facts and myths. Biochem Pharmacol 2023; 213:115626. [PMID: 37247746 DOI: 10.1016/j.bcp.2023.115626] [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] [Received: 04/21/2023] [Revised: 05/22/2023] [Accepted: 05/23/2023] [Indexed: 05/31/2023]
Abstract
The aryl hydrocarbon receptor (AhR) belongs to the essential helix-loop-helix transcription factors family. This receptor has a central role in determining host physiology and a variety of pathophysiologies ranging from inflammation and metabolism to cancer. AhR is a ligand-driven receptor with intricate pharmacology of activation depending on the type and quantity of ligand present. Therefore, a better understanding of AhR ligands per se is critical to move the field forward. In this minireview, we clarify some facts and myths about AhR ligands and how further studies could shed light on the true nature of AhR activation by these ligands. The review covers select chemical classes and explores parameters that qualify them as true receptor ligands.
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Affiliation(s)
- Lucia Sládeková
- Department of Cell Biology and Genetics, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Sridhar Mani
- Department of Genetics and Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Zdeněk Dvořák
- Department of Cell Biology and Genetics, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic.
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Rudyak SG, Usakin LA, Tverye EA, Robertson ED, Panteleyev AA. Aryl hydrocarbon receptor is regulated via multiple mechanisms in human keratinocytes. Toxicol Lett 2023:S0378-4274(23)00185-6. [PMID: 37217010 DOI: 10.1016/j.toxlet.2023.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 05/11/2023] [Accepted: 05/19/2023] [Indexed: 05/24/2023]
Abstract
Aryl hydrocarbon receptor (AhR) is a basic helix-loop-helix transcription factor activated by polycyclic aromatic hydrocarbons of synthetic and natural origin. While a number of novel AhR ligands have been recently identified, little is known about their possible influence on AhR levels and stability. We used western blot, qRT-PCR and immunocytochemistry to determine the effects of AhR ligands on AhR expression in N-TERT (N-TERT1) immortalized human keratinocytes, and immunohistochemistry to assess patterns of AhR expression in human and mouse skin and skin appendages. While AhR was highly expressed in cultured keratinocytes and in the skin, it was found primarily in the cytoplasm, but not in the nucleus, suggesting its inactivity. At the same time, treatment of N-TERT cells with proteasomal inhibitor MG132 and eventual inhibition of AhR degradation resulted in nuclear AhR accumulation. Treatment of keratinocytes with AhR ligands such as TCDD, FICZ, caused near-complete disappearance of AhR, and treatment with I3C resulted in substantially diminished level of AhR possibly due to ligand-induced AhR degradation. The AhR decay was blocked by proteasome inhibition, indicating degradation-based mechanism of regulation. Additionally, AhR decay was blocked by ligand-selective AhR antagonist CH223191, implying substrate-induced mechanism of degradation. Furthermore, degradation of AhR was blocked in N-TERT cells with knockdown of AhR dimerization partner ARNT (HIF1β), suggesting that ARNT is required for AhR proteolysis. However, addition of hypoxia mimetics (HIF1 pathway activators) CoCl2 and DMOG had only minor effects on degradation of AhR. Additionally, inhibition of HDACs with Trichostatin A resulted in enhanced expression of AhR in both untreated and ligand-treated cells. These results demonstrate that in immortalized epidermal keratinocytes AhR is primarily regulated post-translationally via proteasome-mediated degradation, and suggest potential means to manipulate AhR levels and signaling in the skin. Overall, the AhR is regulated via multiple mechanisms, including proteasomal ligand- and ARNT-dependent degradation, and transcriptional regulation by HDACs, implying complex system of balancing its expression and protein stability.
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Affiliation(s)
- S G Rudyak
- Pirogov Russian National Research Medical University, Moscow, Russia.
| | - L A Usakin
- National Research Center "Kurchatov Institute", Moscow, Russia
| | - E A Tverye
- National Research Center "Kurchatov Institute", Moscow, Russia
| | | | - A A Panteleyev
- National Research Center "Kurchatov Institute", Moscow, Russia; A.V. Vishnevsky National Medical Research Center of Surgery, Moscow, Russia.
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Salminen A. Aryl hydrocarbon receptor (AhR) reveals evidence of antagonistic pleiotropy in the regulation of the aging process. Cell Mol Life Sci 2022; 79:489. [PMID: 35987825 PMCID: PMC9392714 DOI: 10.1007/s00018-022-04520-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 07/14/2022] [Accepted: 08/08/2022] [Indexed: 11/24/2022]
Abstract
The antagonistic pleiotropy hypothesis is a well-known evolutionary theory to explain the aging process. It proposes that while a particular gene may possess beneficial effects during development, it can exert deleterious properties in the aging process. The aryl hydrocarbon receptor (AhR) has a significant role during embryogenesis, but later in life, it promotes several age-related degenerative processes. For instance, AhR factor (i) controls the pluripotency of stem cells and the stemness of cancer stem cells, (ii) it enhances the differentiation of embryonal stem cells, especially AhR signaling modulates the differentiation of hematopoietic stem cells and progenitor cells, (iii) it also stimulates the differentiation of immunosuppressive Tregs, Bregs, and M2 macrophages, and finally, (iv) AhR signaling participates in the differentiation of many peripheral tissues. On the other hand, AhR signaling is involved in many processes promoting cellular senescence and pathological processes, e.g., osteoporosis, vascular dysfunction, and the age-related remodeling of the immune system. Moreover, it inhibits autophagy and aggravates extracellular matrix degeneration. AhR signaling also stimulates oxidative stress, promotes excessive sphingolipid synthesis, and disturbs energy metabolism by catabolizing NAD+ degradation. The antagonistic pleiotropy of AhR signaling is based on the complex and diverse connections with major signaling pathways in a context-dependent manner. The major regulatory steps include, (i) a specific ligand-dependent activation, (ii) modulation of both genetic and non-genetic responses, (iii) a competition and crosstalk with several transcription factors, such as ARNT, HIF-1α, E2F1, and NF-κB, and (iv) the epigenetic regulation of target genes with binding partners. Thus, not only mTOR signaling but also the AhR factor demonstrates antagonistic pleiotropy in the regulation of the aging process.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland.
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Sakakibara Y, Kojima A, Asai Y, Nadai M, Katoh M. Changes in uridine 5'-diphospho-glucuronosyltransferase 1A6 expression by histone deacetylase inhibitor valproic acid. Biopharm Drug Dispos 2022; 43:175-182. [PMID: 36000181 DOI: 10.1002/bdd.2328] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 08/10/2022] [Accepted: 08/18/2022] [Indexed: 11/09/2022]
Abstract
Valproic acid (VPA) is well-known as a histone deacetylase (HDAC) inhibitor. It has been reported that HDAC inhibitors enhance basal and aryl hydrocarbon receptor (AhR) ligand-induced aryl hydrocarbon receptor-responsive gene expression. Other studies suggested that HDAC inhibition might significantly activate the NF-E2-related factor-2 (Nrf2). Moreover, VPA activates mitogen-activated protein kinases (MAPKs). MAPK pathways regulate Nrf2 transactivation domain activity. Uridine 5'-diphospho-glucuronosyltransferase (UGT) 1A6 is one of the important isoforms to affect drug pharmacokinetics. UGT1A6 gene is regulated transcriptionally by AhR and Nrf2. The present study aimed to investigate whether UGT1A6 expression was changed by VPA and to elucidate the mechanism of the alteration. Following VPA treatment for 72 h in Caco-2 cells, UGT1A6 mRNA was increased by 7.9-fold. Moreover, UGT1A6 mRNA was increased by other HDAC inhibitors, suggesting that HDAC inhibition caused the UGT1A6 mRNA induction. AhR and Nrf2 proteins in the nucleus of Caco-2 cells were increased by 1.5- and 1.7-fold, respectively, following the VPA treatment. However, VPA treatment did not activate the extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) pathways in Caco-2 cells. In conclusion, we observed that VPA induced UGT1A6 mRNA expression via AhR and Nrf2 pathways, but not via the ERK or JNK pathways.
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Affiliation(s)
| | - Ayaka Kojima
- Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Yuki Asai
- Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | | | - Miki Katoh
- Faculty of Pharmacy, Meijo University, Nagoya, Japan
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Modoux M, Rolhion N, Lefevre JH, Oeuvray C, Nádvorník P, Illes P, Emond P, Parc Y, Mani S, Dvorak Z, Sokol H. Butyrate acts through HDAC inhibition to enhance aryl hydrocarbon receptor activation by gut microbiota-derived ligands. Gut Microbes 2022; 14:2105637. [PMID: 35895845 PMCID: PMC9336500 DOI: 10.1080/19490976.2022.2105637] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Aryl hydrocarbon receptor (AhR) is a critical player in the crosstalk between the gut microbiota and its host. However, factors regulating AhR within the gut, which is a complex metabolomic environment, are poorly understood. This study investigates the effect of a combination of metabolites on the activation mechanism of AhR. AhR activity was evaluated using both a luciferase reporter system and mRNA levels of AhR target genes on human cell lines and human colonic explants. AhR activation was studied by radioligand-binding assay, nuclear translocation of AhR by immuofluorescence and protein co-immunoprecipitation of AhR with ARNT. Indirect activation of AhR was evaluated using several tests and inhibitors. The promoter of the target gene CYP1A1 was studied both by chromatin immunoprecipitation and by using an histone deacetylase HDAC inhibitor (iHDAC). Short-chain fatty acids, and butyrate in particular, enhance AhR activity mediated by endogenous tryptophan metabolites without binding to the receptor. This effect was confirmed in human intestinal explants and did not rely on activation of receptors targeted by SCFAs, inhibition of AhR degradation or clearance of its ligands. Butyrate acted directly on AhR target gene promoter to reshape chromatin through iHDAC activity. Our findings revealed that butyrate is not an AhR ligand but acts as iHDAC leading to an increase recruitment of AhR to the target gene promoter in the presence of tryptophan-derived AhR agonists. These data contribute to a novel understanding of the complex regulation of AhR activation by gut microbiota-derived metabolites.
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Affiliation(s)
- Morgane Modoux
- Sorbonne Université, INSERM, Centre de Recherche Saint-Antoine, CRSA, AP-HP, Saint Antoine Hospital, Gastroenterology Department, Paris, France,Paris Centre for Microbiome Medicine (PaCeMM) FHU, Paris, France
| | - Nathalie Rolhion
- Sorbonne Université, INSERM, Centre de Recherche Saint-Antoine, CRSA, AP-HP, Saint Antoine Hospital, Gastroenterology Department, Paris, France,Paris Centre for Microbiome Medicine (PaCeMM) FHU, Paris, France
| | - Jeremie H. Lefevre
- Paris Centre for Microbiome Medicine (PaCeMM) FHU, Paris, France,Sorbonne Université, Department of Digestive Surgery, AP-HP, Hôpital Saint Antoine, Paris, France
| | - Cyriane Oeuvray
- Sorbonne Université, INSERM, Centre de Recherche Saint-Antoine, CRSA, AP-HP, Saint Antoine Hospital, Gastroenterology Department, Paris, France,Paris Centre for Microbiome Medicine (PaCeMM) FHU, Paris, France
| | - Petr Nádvorník
- Departments of Cell Biology and Genetics, Palacký University, Olomouc, Czech Republic
| | - Peter Illes
- Departments of Cell Biology and Genetics, Palacký University, Olomouc, Czech Republic
| | - Patrick Emond
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, Centre-Val de Loire, France
| | - Yann Parc
- Sorbonne Université, Department of Digestive Surgery, AP-HP, Hôpital Saint Antoine, Paris, France
| | - Sridhar Mani
- Departments of Molecular Pharmacology, Genetics and Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Zdenek Dvorak
- Departments of Cell Biology and Genetics, Palacký University, Olomouc, Czech Republic
| | - Harry Sokol
- Sorbonne Université, INSERM, Centre de Recherche Saint-Antoine, CRSA, AP-HP, Saint Antoine Hospital, Gastroenterology Department, Paris, France,Paris Centre for Microbiome Medicine (PaCeMM) FHU, Paris, France,INRAe, UMR1319 Micalis & AgroParisTech, Jouy en Josas, France,CONTACT Harry Sokol Sorbonne Université, INSERM, Centre de Recherche Saint-Antoine, CRSA, AP-HP, Saint Antoine Hospital, Gastroenterology Department, ParisF-75012, France
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Zhu JJ, Stenfeldt C, Bishop EA, Canter JA, Eschbaumer M, Rodriguez LL, Arzt J. Inferred Causal Mechanisms of Persistent FMDV Infection in Cattle from Differential Gene Expression in the Nasopharyngeal Mucosa. Pathogens 2022; 11:pathogens11080822. [PMID: 35894045 PMCID: PMC9329776 DOI: 10.3390/pathogens11080822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/14/2022] [Accepted: 07/18/2022] [Indexed: 02/05/2023] Open
Abstract
Foot-and-mouth disease virus (FMDV) can persistently infect pharyngeal epithelia in ruminants but not in pigs. Our previous studies demonstrated that persistent FMDV infection in cattle was associated with under-expression of several chemokines that recruit immune cells. This report focuses on the analysis of differentially expressed genes (DEG) identified during the transitional phase of infection, defined as the period when animals diverge between becoming carriers or terminators. During this phase, Th17-stimulating cytokines (IL6 and IL23A) and Th17-recruiting chemokines (CCL14 and CCL20) were upregulated in animals that were still infected (transitional carriers) compared to those that had recently cleared infection (terminators), whereas chemokines recruiting neutrophils and CD8+ T effector cells (CCL3 and ELR+CXCLs) were downregulated. Upregulated Th17-specific receptor, CCR6, and Th17-associated genes, CD146, MIR155, and ThPOK, suggested increased Th17 cell activity in transitional carriers. However, a complex interplay of the Th17 regulatory axis was indicated by non-significant upregulation of IL17A and downregulation of IL17F, two hallmarks of TH17 activity. Other DEG suggested that transitional carriers had upregulated aryl hydrocarbon receptor (AHR), non-canonical NFκB signaling, and downregulated canonical NFκB signaling. The results described herein provide novel insights into the mechanisms of establishment of FMDV persistence. Additionally, the fact that ruminants, unlike pigs, produce a large amount of AHR ligands suggests a plausible explanation of why FMDV persists in ruminants, but not in pigs.
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Affiliation(s)
- James J. Zhu
- Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Orient, NY 11957, USA; (C.S.); (E.A.B.); (J.A.C.); (L.L.R.)
- Correspondence: (J.J.Z.); (J.A.); Tel.: +1-631-323-3340 (J.J.Z.); +1-631-323-4421 (J.A.); Fax: +1-631-323-3006 (J.A.)
| | - Carolina Stenfeldt
- Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Orient, NY 11957, USA; (C.S.); (E.A.B.); (J.A.C.); (L.L.R.)
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA
| | - Elizabeth A. Bishop
- Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Orient, NY 11957, USA; (C.S.); (E.A.B.); (J.A.C.); (L.L.R.)
| | - Jessica A. Canter
- Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Orient, NY 11957, USA; (C.S.); (E.A.B.); (J.A.C.); (L.L.R.)
- Plum Island Animal Disease Center Research Participation Program, Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN 37830, USA
| | - Michael Eschbaumer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, 17493 Greifswald-Insel Riems, Germany;
| | - Luis L. Rodriguez
- Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Orient, NY 11957, USA; (C.S.); (E.A.B.); (J.A.C.); (L.L.R.)
| | - Jonathan Arzt
- Foreign Animal Disease Research Unit, Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Orient, NY 11957, USA; (C.S.); (E.A.B.); (J.A.C.); (L.L.R.)
- Correspondence: (J.J.Z.); (J.A.); Tel.: +1-631-323-3340 (J.J.Z.); +1-631-323-4421 (J.A.); Fax: +1-631-323-3006 (J.A.)
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Jourova L, Anzenbacherova E, Dostal Z, Anzenbacher P, Briolotti P, Rigal E, Daujat-Chavanieu M, Gerbal-Chaloin S. Butyrate, a typical product of gut microbiome, affects function of the AhR gene, being a possible agent of crosstalk between gut microbiome and hepatic drug metabolism. J Nutr Biochem 2022; 107:109042. [PMID: 35533897 DOI: 10.1016/j.jnutbio.2022.109042] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 01/11/2022] [Accepted: 03/21/2022] [Indexed: 02/06/2023]
Abstract
Modulation of gut microbiome composition seems to be a promising therapeutic strategy for a wide range of pathological states. However, these microbiota-targeted interventions may affect production of microbial metabolites, circulating factors in the gut-liver axis influencing hepatic drug metabolism with possible clinical relevance. Butyrate, a short-chain fatty acid produced through microbial fermentation of dietary fibers in the colon, has well established anti-inflammatory role in the intestine, while the effect of butyrate on the liver is unknown. In this study, we have evaluated the effect of butyrate on hepatic AhR activity and AhR-regulated gene expression. We have showed that AhR and its target genes were upregulated by butyrate in dose dependent manner in HepG2-C3 as well as in primary human hepatocytes. The involvement of AhR has been proved using specific AhR antagonist and siRNA-mediated AhR silencing. Experiments with AhR reporter cells have shown that butyrate regulates the expression of AhR target genes by modulating the AhR activity. Our results suggest also epigenetic action by butyrate on AhR and its repressor (AHRR) presumably through mechanisms based on HDAC inhibition in the liver. Our results demonstrate that butyrate may influence the drug metabolizing ability of liver enzymes e.g. through the interaction with AhR dependent pathways.
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Affiliation(s)
- Lenka Jourova
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacky University Olomouc, Hněvotínská 3, Olomouc 775 15, Czech Republic.
| | - Eva Anzenbacherova
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacky University Olomouc, Hněvotínská 3, Olomouc 775 15, Czech Republic
| | - Zdenek Dostal
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacky University Olomouc, Hněvotínská 3, Olomouc 775 15, Czech Republic
| | - Pavel Anzenbacher
- Department of Pharmacology, Faculty of Medicine and Dentistry, Palacky University Olomouc, Hněvotínská 3, Olomouc 775 15, Czech Republic
| | - Philippe Briolotti
- IRMB, University Montpellier, INSERM, CHU Montpellier, Montpellier, France
| | - Emilie Rigal
- IRMB, University Montpellier, INSERM, CHU Montpellier, Montpellier, France
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11
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Akishina AA, Cherezov RO, Vorontsova YE, Simonova OB. Effect of the Histone Deacetylase (HDAC) Inhibitor Belinostat on the Expression of the Aryl Hydrocarbon Receptor and its Target Genes in Human Cell Cultures. Russ J Dev Biol 2022. [DOI: 10.1134/s1062360422020023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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The Aryl Hydrocarbon Receptor (AHR): A Novel Therapeutic Target for Pulmonary Diseases? Int J Mol Sci 2022; 23:ijms23031516. [PMID: 35163440 PMCID: PMC8836075 DOI: 10.3390/ijms23031516] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 12/30/2021] [Accepted: 01/13/2022] [Indexed: 01/08/2023] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a cytoplasmic transcription factor that is well-known for regulating xenobiotic metabolism. Studies in knockout and transgenic mice indicate that the AHR plays a vital role in the development of liver and regulation of reproductive, cardiovascular, hematopoietic, and immune homeostasis. In this focused review on lung diseases associated with acute injury and alveolar development, we reviewed and summarized the current literature on the mechanistic role(s) and therapeutic potential of the AHR in acute lung injury, chronic obstructive pulmonary disease, and bronchopulmonary dysplasia (BPD). Pre-clinical studies indicate that endogenous AHR activation is necessary to protect neonatal and adult lungs against hyperoxia- and cigarette smoke-induced injury. Our goal is to provide insight into the high translational potential of the AHR in the meaningful management of infants and adults with these lung disorders that lack curative therapies.
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13
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Akhtar S, Hourani S, Therachiyil L, Al-Dhfyan A, Agouni A, Zeidan A, Uddin S, Korashy HM. Epigenetic Regulation of Cancer Stem Cells by the Aryl Hydrocarbon Receptor Pathway. Semin Cancer Biol 2020; 83:177-196. [PMID: 32877761 DOI: 10.1016/j.semcancer.2020.08.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/20/2020] [Accepted: 08/23/2020] [Indexed: 12/14/2022]
Abstract
Compelling evidence has demonstrated that tumor bulk comprises distinctive subset of cells generally referred as cancer stem cells (CSCs) that have been proposed as a strong sustainer and promoter of tumorigenesis and therapeutic resistance. These distinguished properties of CSCs have raised interest in understanding the molecular mechanisms that govern the maintenance of these cells. Numerous experimental and epidemiological studies have demonstrated that exposure to environmental toxins such as the polycyclic aromatic hydrocarbons (PAHs) is strongly involved in cancer initiation and progression. The PAH-induced carcinogenesis is shown to be mediated through the activation of a cytosolic receptor, aryl hydrocarbon receptor (AhR)/Cytochrome P4501A pathway, suggesting a possible direct link between AhR and CSCs. Several recent studies have investigated the role of AhR in CSCs self-renewal and maintenance, however the molecular mechanisms and particularly the epigenetic regulations of CSCs by the AhR/CYP1A pathway have not been reviewed before. In this review, we first summarize the crosstalk between AhR and cancer genetics, with a particular emphasis on the mechanisms relevant to CSCs such as Wnt/β-catenin, Notch, NF-κB, and PTEN-PI3K/Akt signaling pathways. The second part of this review discusses the recent advances and studies highlighting the epigenetic mechanisms mediated by the AhR/CYP1A pathway that control CSC gene expression, self-renewal, and chemoresistance in various human cancers. Furthermore, the review also sheds light on the importance of targeting the epigenetic pathways as a novel therapeutic approach against CSCs.
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Affiliation(s)
- Sabah Akhtar
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha, Qatar
| | - Shireen Hourani
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha, Qatar
| | - Lubna Therachiyil
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha, Qatar; Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar
| | - Abdullah Al-Dhfyan
- Stem Cell & Tissue Re-Engineering, King Faisal Specialist Hospital and Research Centre, Riyadh, 11211, Saudi Arabia
| | - Abdelali Agouni
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha, Qatar
| | - Asad Zeidan
- Department of Biomedical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Shahab Uddin
- Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar
| | - Hesham M Korashy
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha, Qatar.
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14
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Rannug A. How the AHR Became Important in Intestinal Homeostasis-A Diurnal FICZ/AHR/CYP1A1 Feedback Controls Both Immunity and Immunopathology. Int J Mol Sci 2020; 21:ijms21165681. [PMID: 32784381 PMCID: PMC7461111 DOI: 10.3390/ijms21165681] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/12/2022] Open
Abstract
Ever since the 1970s, when profound immunosuppression caused by exogenous dioxin-like compounds was first observed, the involvement of the aryl hydrocarbon receptor (AHR) in immunomodulation has been the focus of considerable research interest. Today it is established that activation of this receptor by its high-affinity endogenous ligand, 6-formylindolo[3,2-b]carbazole (FICZ), plays important physiological roles in maintaining epithelial barriers. In the gut lumen, the small amounts of FICZ that are produced from L-tryptophan by microbes are normally degraded rapidly by the inducible cytochrome P4501A1 (CYP1A1) enzyme. This review describes how when the metabolic clearance of FICZ is attenuated by inhibition of CYP1A1, this compound passes through the intestinal epithelium to immune cells in the lamina propria. FICZ, the level of which is thus modulated by this autoregulatory loop involving FICZ itself, the AHR and CYP1A1, plays a central role in maintaining gut homeostasis by potently up-regulating the expression of interleukin 22 (IL-22) by group 3 innate lymphoid cells (ILC3s). IL-22 stimulates various epithelial cells to produce antimicrobial peptides and mucus, thereby both strengthening the epithelial barrier against pathogenic microbes and promoting colonization by beneficial bacteria. Dietary phytochemicals stimulate this process by inhibiting CYP1A1 and causing changes in the composition of the intestinal microbiota. The activity of CYP1A1 can be increased by other microbial products, including the short-chain fatty acids, thereby accelerating clearance of FICZ. In particular, butyrate enhances both the level of the AHR and CYP1A1 activity by stimulating histone acetylation, a process involved in the daily cycle of the FICZ/AHR/CYP1A1 feedback loop. It is now of key interest to examine the potential involvement of FICZ, a major physiological activator of the AHR, in inflammatory disorders and autoimmunity.
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Affiliation(s)
- Agneta Rannug
- Karolinska Institutet, Institute of Environmental Medicine, 171 77 Stockholm, Sweden
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15
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You D, Richardson JR, Aleksunes LM. Epigenetic Regulation of Multidrug Resistance Protein 1 and Breast Cancer Resistance Protein Transporters by Histone Deacetylase Inhibition. Drug Metab Dispos 2020; 48:459-480. [PMID: 32193359 DOI: 10.1124/dmd.119.089953] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 02/13/2020] [Indexed: 02/06/2023] Open
Abstract
Multidrug resistance protein 1 (MDR1, ABCB1, P-glycoprotein) and breast cancer resistance protein (BCRP, ABCG2) are key efflux transporters that mediate the extrusion of drugs and toxicants in cancer cells and healthy tissues, including the liver, kidneys, and the brain. Altering the expression and activity of MDR1 and BCRP influences the disposition, pharmacodynamics, and toxicity of chemicals, including a number of commonly prescribed medications. Histone acetylation is an epigenetic modification that can regulate gene expression by changing the accessibility of the genome to transcriptional regulators and transcriptional machinery. Recently, studies have suggested that pharmacological inhibition of histone deacetylases (HDACs) modulates the expression and function of MDR1 and BCRP transporters as a result of enhanced histone acetylation. This review addresses the ability of HDAC inhibitors to modulate the expression and the function of MDR1 and BCRP transporters and explores the molecular mechanisms by which HDAC inhibition regulates these transporters. While the majority of studies have focused on histone regulation of MDR1 and BCRP in drug-resistant and drug-sensitive cancer cells, emerging data point to similar responses in nonmalignant cells and tissues. Elucidating epigenetic mechanisms regulating MDR1 and BCRP is important to expand our understanding of the basic biology of these two key transporters and subsequent consequences on chemoresistance as well as tissue exposure and responses to drugs and toxicants. SIGNIFICANCE STATEMENT: Histone deacetylase inhibitors alter the expression of key efflux transporters multidrug resistance protein 1 and breast cancer resistance protein in healthy and malignant cells.
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Affiliation(s)
- Dahea You
- Joint Graduate Program in Toxicology, Rutgers, The State University of New Jersey, Piscataway, New Jersey (D.Y.); Department of Environmental Health Sciences, Robert Stempel School of Public Health and Social Work, Florida International University, Miami, Florida (J.R.R.); Environmental and Occupational Health Sciences Institute, Piscataway, New Jersey (J.R.R., L.M.A.); and Department of Pharmacology and Toxicology, Rutgers, The State University of New Jersey, Ernest Mario School of Pharmacy, Piscataway, New Jersey (L.M.A.)
| | - Jason R Richardson
- Joint Graduate Program in Toxicology, Rutgers, The State University of New Jersey, Piscataway, New Jersey (D.Y.); Department of Environmental Health Sciences, Robert Stempel School of Public Health and Social Work, Florida International University, Miami, Florida (J.R.R.); Environmental and Occupational Health Sciences Institute, Piscataway, New Jersey (J.R.R., L.M.A.); and Department of Pharmacology and Toxicology, Rutgers, The State University of New Jersey, Ernest Mario School of Pharmacy, Piscataway, New Jersey (L.M.A.)
| | - Lauren M Aleksunes
- Joint Graduate Program in Toxicology, Rutgers, The State University of New Jersey, Piscataway, New Jersey (D.Y.); Department of Environmental Health Sciences, Robert Stempel School of Public Health and Social Work, Florida International University, Miami, Florida (J.R.R.); Environmental and Occupational Health Sciences Institute, Piscataway, New Jersey (J.R.R., L.M.A.); and Department of Pharmacology and Toxicology, Rutgers, The State University of New Jersey, Ernest Mario School of Pharmacy, Piscataway, New Jersey (L.M.A.)
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16
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Tsai CH, Li CH, Liao PL, Chang YW, Cheng YW, Kang JJ. Aza-PBHA, a potent histone deacetylase inhibitor, inhibits human gastric-cancer cell migration via PKCα-mediated AHR-HDAC interactions. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1867:118564. [PMID: 31672612 DOI: 10.1016/j.bbamcr.2019.118564] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 10/16/2019] [Accepted: 10/23/2019] [Indexed: 12/19/2022]
Abstract
Recently, histone deacetylase inhibitors (HDACi) have become widely used in anti-cancer treatment; however, due to acquired drug resistance and their relatively low specificity, they are largely ineffective against late-stage cancer. Thus, it is critical to elucidate the molecular mechanisms underlying these issues, so as to identify novel therapeutic targets to prevent late-stage cancer progression and resistance acquisition. The present study investigated the Aryl hydrocarbon receptor (AHR), that has been shown to mediate histone acetylation by regulating histone deacetylase (HDAC) activity during HDACi treatment in human gastric-cancer cell lines (i.e. AGS and NCI-N87 cells). The potent HDACi, Aza-PBHA, was thus shown to upregulate AHR expression in both AGS and NCI-N87 cell lines, and to increase histone acetylation levels by facilitating AHR/HDAC interactions. Conversely, AHR knockdown increased HDAC activity. Aza-PBHA also increased PKCα phosphorylation and membrane translocation; however, interestingly, PKCα inhibition reduced the Aza-PBHA-increased AHR and histone acetylation levels, and inhibited the formation of the AHR/HDAC complex, likely upregulating Aza-PBHA-inhibited cell migration. Thus, our results suggest that Aza-PBHA treatment increased AHR levels to suppress HDAC activity, and inhibited cell migration by activating PKCα activation. These findings support the use of drugs to control AHR-related epigenetic regulation as a promising potential method to prevent acquired resistance to cancer treatments.
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Affiliation(s)
- Chi-Hao Tsai
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan; School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan.
| | - Ching-Hao Li
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taiwan.
| | - Po-Lin Liao
- Institute of Food Safety and Health Assessment, National Yang-Ming University, Taipei, Taiwan
| | - Yu-Wei Chang
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan.
| | - Yu-Wen Cheng
- School of Pharmacy, College of Pharmacy, Taipei Medical University, Taipei, Taiwan; Ph.D. Program for the Clinical Drug Discovery from Botanical Herbs, College of Pharmacy, Taipei Medical University, Taiwan; Ph.D. Program in Biotechnology Research and Development, College of Pharmacy, Taipei Medical University, Taiwan.
| | - Jaw-Jou Kang
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan; Faculty of Pharmacy, National Yang-Ming University, Taipei, Taiwan.
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17
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Matvere A, Teino I, Varik I, Kuuse S, Tiido T, Kristjuhan A, Maimets T. FSH/LH-Dependent Upregulation of Ahr in Murine Granulosa Cells Is Controlled by PKA Signaling and Involves Epigenetic Regulation. Int J Mol Sci 2019; 20:ijms20123068. [PMID: 31234584 PMCID: PMC6627912 DOI: 10.3390/ijms20123068] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/20/2019] [Accepted: 06/21/2019] [Indexed: 12/12/2022] Open
Abstract
The aryl hydrocarbon receptor (Ahr) is a ligand-activated transcription factor primarily known for its toxicological functions. Recent studies have established its importance in many physiological processes including female reproduction, although there is limited data about the precise mechanisms how Ahr itself is regulated during ovarian follicle maturation. This study describes the expression of Ahr in ovarian granulosa cells (GCs) of immature mice in a gonadotropin-dependent manner. We show that Ahr upregulation in vivo requires both follicle stimulating hormone (FSH) and luteinizing hormone (LH) activities. FSH alone increased Ahr mRNA, but had no effect on Ahr protein level, implicating a possible LH-dependent post-transcriptional regulation. Also, the increase in Ahr protein is specific to large antral follicles in induced follicle maturation. We show that Ahr expression in GCs of mid-phase follicular maturation is downregulated by protein kinase A (PKA) signaling and activation of Ahr promoter is regulated by chromatin remodeling.
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Affiliation(s)
- Antti Matvere
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia.
| | - Indrek Teino
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia.
| | - Inge Varik
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia.
| | - Sulev Kuuse
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia.
| | - Tarmo Tiido
- Clinical Research Centre, National Centre of Translational and Clinical Research, University of Tartu, Ravila 19, 50411 Tartu, Estonia.
| | - Arnold Kristjuhan
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia.
| | - Toivo Maimets
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia.
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18
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Viluksela M, Pohjanvirta R. Multigenerational and Transgenerational Effects of Dioxins. Int J Mol Sci 2019; 20:E2947. [PMID: 31212893 PMCID: PMC6627869 DOI: 10.3390/ijms20122947] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 12/12/2022] Open
Abstract
Dioxins are ubiquitous and persistent environmental contaminants whose background levels are still reason for concern. There is mounting evidence from both epidemiological and experimental studies that paternal exposure to the most potent congener of dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), can lower the male/female ratio of offspring. Moreover, in laboratory rodents and zebrafish, TCDD exposure of parent animals has been reported to result in reduced reproductive performance along with other adverse effects in subsequent generations, foremost through the paternal but also via the maternal germline. These impacts have been accompanied by epigenetic alterations in placenta and/or sperm cells, including changes in methylation patterns of imprinted genes. Here, we review recent key studies in this field with an attempt to provide an up-to-date picture of the present state of knowledge to the reader. These studies provide biological plausibility for the potential of dioxin exposure at a critical time-window to induce epigenetic alterations across multiple generations and the significance of aryl hydrocarbon receptor (AHR) in mediating these effects. Currently available data do not allow to accurately estimate the human health implications of these findings, although epidemiological evidence on lowered male/female ratio suggests that this effect may take place at realistic human exposure levels.
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Affiliation(s)
- Matti Viluksela
- School of Pharmacy and Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.
- Environmental Health Unit, National Institute for Health and Welfare, P.O. Box 95, FI-70701 Kuopio, Finland.
| | - Raimo Pohjanvirta
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 66, FI-00014 Helsinki, Finland.
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19
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Identification of the novel role of butyrate as AhR ligand in human intestinal epithelial cells. Sci Rep 2019; 9:643. [PMID: 30679727 PMCID: PMC6345974 DOI: 10.1038/s41598-018-37019-2] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/28/2018] [Indexed: 12/18/2022] Open
Abstract
The ligand activated transcription factor, aryl hydrocarbon receptor (AhR) emerged as a critical regulator of immune and metabolic processes in the gastrointestinal tract. In the gut, a main source of AhR ligands derives from commensal bacteria. However, many of the reported microbiota-derived ligands have been restricted to indolyl metabolites. Here, by screening commensal bacteria supernatants on an AhR reporter system expressed in human intestinal epithelial cell line (IEC), we found that the short chain fatty acid (SCFA) butyrate induced AhR activity and the transcription of AhR-dependent genes in IECs. We showed that AhR ligand antagonists reduced the effects of butyrate on IEC suggesting that butyrate could act as a ligand of AhR, which was supported by the nuclear translocation of AhR induced by butyrate and in silico structural modelling. In conclusion, our findings suggest that (i) butyrate activates AhR pathway and AhR-dependent genes in human intestinal epithelial cell-lines (ii) butyrate is a potential ligand for AhR which is an original mechanism of gene regulation by SCFA.
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20
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Knutsen HK, Alexander J, Barregård L, Bignami M, Brüschweiler B, Ceccatelli S, Cottrill B, Dinovi M, Edler L, Grasl-Kraupp B, Hogstrand C, Nebbia CS, Oswald IP, Petersen A, Rose M, Roudot AC, Schwerdtle T, Vleminckx C, Vollmer G, Wallace H, Fürst P, Håkansson H, Halldorsson T, Lundebye AK, Pohjanvirta R, Rylander L, Smith A, van Loveren H, Waalkens-Berendsen I, Zeilmaker M, Binaglia M, Gómez Ruiz JÁ, Horváth Z, Christoph E, Ciccolallo L, Ramos Bordajandi L, Steinkellner H, Hoogenboom LR. Risk for animal and human health related to the presence of dioxins and dioxin-like PCBs in feed and food. EFSA J 2018; 16:e05333. [PMID: 32625737 PMCID: PMC7009407 DOI: 10.2903/j.efsa.2018.5333] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The European Commission asked EFSA for a scientific opinion on the risks for animal and human health related to the presence of dioxins (PCDD/Fs) and DL-PCBs in feed and food. The data from experimental animal and epidemiological studies were reviewed and it was decided to base the human risk assessment on effects observed in humans and to use animal data as supportive evidence. The critical effect was on semen quality, following pre- and postnatal exposure. The critical study showed a NOAEL of 7.0 pg WHO2005-TEQ/g fat in blood sampled at age 9 years based on PCDD/F-TEQs. No association was observed when including DL-PCB-TEQs. Using toxicokinetic modelling and taking into account the exposure from breastfeeding and a twofold higher intake during childhood, it was estimated that daily exposure in adolescents and adults should be below 0.25 pg TEQ/kg bw/day. The CONTAM Panel established a TWI of 2 pg TEQ/kg bw/week. With occurrence and consumption data from European countries, the mean and P95 intake of total TEQ by Adolescents, Adults, Elderly and Very Elderly varied between, respectively, 2.1 to 10.5, and 5.3 to 30.4 pg TEQ/kg bw/week, implying a considerable exceedance of the TWI. Toddlers and Other Children showed a higher exposure than older age groups, but this was accounted for when deriving the TWI. Exposure to PCDD/F-TEQ only was on average 2.4- and 2.7-fold lower for mean and P95 exposure than for total TEQ. PCDD/Fs and DL-PCBs are transferred to milk and eggs, and accumulate in fatty tissues and liver. Transfer rates and bioconcentration factors were identified for various species. The CONTAM Panel was not able to identify reference values in most farm and companion animals with the exception of NOAELs for mink, chicken and some fish species. The estimated exposure from feed for these species does not imply a risk.
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21
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Roman ÁC, Carvajal-Gonzalez JM, Merino JM, Mulero-Navarro S, Fernández-Salguero PM. The aryl hydrocarbon receptor in the crossroad of signalling networks with therapeutic value. Pharmacol Ther 2017; 185:50-63. [PMID: 29258844 DOI: 10.1016/j.pharmthera.2017.12.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is well-known for its major contributions to the cellular responses against environmental toxins and carcinogens. Notably, AhR has also emerged as a key transcription factor controlling many physiological processes including cell proliferation and apoptosis, differentiation, adhesion and migration, pluripotency and stemness. These novel functions have broadened our understanding of the signalling pathways and molecular intermediates interacting with AhR under both homeostatic and pathological conditions. Recent discoveries link AhR with the function of essential organs such as liver, skin and gonads, and with complex organismal structures including the immune and cardiovascular systems. The identification of potential endogenous ligands able to regulate AhR activity, opens the possibility of designing ad hoc molecules with pharmacological and/or therapeutic value to treat human diseases in which AhR may have a causal role. Integration of experimental data from in vitro and in vivo studies with "omic" analyses of human patients affected with cancer, immune diseases, inflammation or neurological disorders will likely contribute to validate the clinical relevance of AhR and the possible benefits of modulating its activity by pharmacologically-driven strategies. In this review, we will highlight signalling pathways involved in human diseases that could be targetable by AhR modulators and discuss the feasibility of using such molecules in therapy. The pros and cons of AhR-aimed approaches will be also mentioned.
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Affiliation(s)
- Ángel C Roman
- Champalimaud Neuroscience Programme, Champalimoud Center for the Unknown, Lisbon, Portugal
| | - José M Carvajal-Gonzalez
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain
| | - Jaime M Merino
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain
| | - Sonia Mulero-Navarro
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain.
| | - Pedro M Fernández-Salguero
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain.
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22
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Short Chain Fatty Acids Enhance Aryl Hydrocarbon (Ah) Responsiveness in Mouse Colonocytes and Caco-2 Human Colon Cancer Cells. Sci Rep 2017; 7:10163. [PMID: 28860561 PMCID: PMC5579248 DOI: 10.1038/s41598-017-10824-x] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 08/15/2017] [Indexed: 02/07/2023] Open
Abstract
Aryl hydrocarbon receptor (AhR) ligands are important for gastrointestinal health and play a role in gut inflammation and the induction of T regulatory cells, and the short chain fatty acids (SCFAs) butyrate, propionate and acetate also induce similar protective responses. Initial studies with butyrate demonstrated that this compound significantly increased expression of Ah-responsive genes such as Cyp1a1/CYP1A1 in YAMC mouse colonocytes and Caco-2 human colon cancer cell lines. Butyrate synergistically enhanced AhR ligand-induced Cyp1a1/CYP1A1 in these cells with comparable enhancement being observed for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and also microbiota-derived AhR ligands tryptamine, indole and 1,4-dihydroxy-2-naphthoic acid (DHNA). The effects of butyrate on enhancing induction of Cyp1b1/CYP1B1, AhR repressor (Ahrr/AhRR) and TCDD-inducible poly(ADP-ribose)polymerase (Tiparp/TiPARP) by AhR ligands were gene- and cell context-dependent with the Caco-2 cells being the most responsive cell line. Like butyrate and propionate, the prototypical hydroxyamic acid-derived histone deacetylase (HDAC) inhibitors Panobinostat and Vorinostat also enhanced AhR ligand-mediated induction and this was accompanied by enhanced histone acetylation. Acetate also enhanced basal and ligand-inducible Ah responsiveness and histone acetylation, demonstrating that acetate was an HDAC inhibitor. These results demonstrate SCFA-AhR ligand interactions in YAMC and Caco-2 cells where SCFAs synergistically enhance basal and ligand-induced expression of AhR-responsive genes.
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Matsuda S, Adachi J, Ihara M, Tanuma N, Shima H, Kakizuka A, Ikura M, Ikura T, Matsuda T. Nuclear pyruvate kinase M2 complex serves as a transcriptional coactivator of arylhydrocarbon receptor. Nucleic Acids Res 2016; 44:636-47. [PMID: 26405201 PMCID: PMC4737187 DOI: 10.1093/nar/gkv967] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 09/13/2015] [Accepted: 09/15/2015] [Indexed: 11/15/2022] Open
Abstract
Pyruvate kinase M2 (PKM2) and pyruvate dehydrogenase complex (PDC) regulate production of acetyl-CoA, which functions as an acetyl donor in diverse enzymatic reactions, including histone acetylation. However, the mechanism by which the acetyl-CoA required for histone acetylation is ensured in a gene context-dependent manner is not clear. Here we show that PKM2, the E2 subunit of PDC and histone acetyltransferase p300 constitute a complex on chromatin with arylhydrocarbon receptor (AhR), a transcription factor associated with xenobiotic metabolism. All of these factors are recruited to the enhancer of AhR-target genes, in an AhR-dependent manner. PKM2 contributes to enhancement of transcription of cytochrome P450 1A1 (CYP1A1), an AhR-target gene, acetylation at lysine 9 of histone H3 at the CYP1A1 enhancer. Site-directed mutagenesis of PKM2 indicates that this enhancement of histone acetylation requires the pyruvate kinase activity of the enzyme. Furthermore, we reveal that PDC activity is present in nuclei. Based on these findings, we propose a local acetyl-CoA production system in which PKM2 and PDC locally supply acetyl-CoA to p300 from abundant PEP for histone acetylation at the gene enhancer, and our data suggest that PKM2 sensitizes AhR-mediated detoxification in actively proliferating cells such as cancer and fetal cells.
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Affiliation(s)
- Shun Matsuda
- Research Center for Environmental Quality Management, Kyoto University, Shiga 520-0811, Japan
| | - Jun Adachi
- Laboratory of Proteome Research, National Institute of Biomedical Innovation, Osaka 567-0085, Japan
| | - Masaru Ihara
- Research Center for Environmental Quality Management, Kyoto University, Shiga 520-0811, Japan
| | - Nobuhiro Tanuma
- Division of Cancer Chemotherapy, Miyagi Cancer Center Research Institute, Miyagi 981-1293, Japan
| | - Hiroshi Shima
- Division of Cancer Chemotherapy, Miyagi Cancer Center Research Institute, Miyagi 981-1293, Japan
| | - Akira Kakizuka
- Laboratory of Functional Biology, Kyoto University Graduate School of Biostudies, Kyoto 606-8501, Japan
| | - Masae Ikura
- Laboratory of Chromatin Regulatory Network, Department of Mutagenesis, Radiation Biology Center, Kyoto University, Kyoto 606-8501, Japan
| | - Tsuyoshi Ikura
- Laboratory of Chromatin Regulatory Network, Department of Mutagenesis, Radiation Biology Center, Kyoto University, Kyoto 606-8501, Japan
| | - Tomonari Matsuda
- Research Center for Environmental Quality Management, Kyoto University, Shiga 520-0811, Japan
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24
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Ding J, Dirks WG, Ehrentraut S, Geffers R, MacLeod RAF, Nagel S, Pommerenke C, Romani J, Scherr M, Vaas LAI, Zaborski M, Drexler HG, Quentmeier H. BCL6--regulated by AhR/ARNT and wild-type MEF2B--drives expression of germinal center markers MYBL1 and LMO2. Haematologica 2015; 100:801-9. [PMID: 25769544 DOI: 10.3324/haematol.2014.120048] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 03/04/2015] [Indexed: 12/28/2022] Open
Abstract
Genetic heterogeneity is widespread in tumors, but poorly documented in cell lines. According to immunoglobulin hypermutation analysis, the diffuse large B-cell lymphoma cell line U-2932 comprises two subpopulations faithfully representing original tumor subclones. We set out to identify molecular causes underlying subclone-specific expression affecting 221 genes including surface markers and the germinal center oncogenes BCL6 and MYC. Genomic copy number variations explained 58/221 genes differentially expressed in the two U-2932 clones. Subclone-specific expression of the aryl-hydrocarbon receptor (AhR) and the resulting activity of the AhR/ARNT complex underlaid differential regulation of 11 genes including MEF2B. Knock-down and inhibitor experiments confirmed that AhR/ARNT regulates MEF2B, a key transcription factor for BCL6. AhR, MEF2B and BCL6 levels correlated not only in the U-2932 subclones but in the majority of 23 cell lines tested, indicting overexpression of AhR as a novel mechanism behind BCL6 diffuse large B-cell lymphoma. Enforced modulation of BCL6 affected 48/221 signature genes. Although BCL6 is known as a transcriptional repressor, 28 genes were up-regulated, including LMO2 and MYBL1 which, like BCL6, signify germinal center diffuse large B-cell lymphoma. Supporting the notion that BCL6 can induce gene expression, BCL6 and the majority of potential targets were co-regulated in a series of B-cell lines. In conclusion, genomic copy number aberrations, activation of AhR/ARNT, and overexpression of BCL6 are collectively responsible for differential expression of more than 100 genes in subclones of the U-2932 cell line. It is particularly interesting that BCL6 - regulated by AhR/ARNT and wild-type MEF2B - may drive expression of germinal center markers in diffuse large B-cell lymphoma.
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Affiliation(s)
- Jie Ding
- Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig
| | - Wilhelm G Dirks
- Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig
| | - Stefan Ehrentraut
- Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig
| | - Robert Geffers
- Helmholtz Centre for Infection Research, Genome Analysis Research Group, Braunschweig
| | - Roderick A F MacLeod
- Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig
| | - Stefan Nagel
- Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig
| | - Claudia Pommerenke
- Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig
| | - Julia Romani
- Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig
| | - Michaela Scherr
- Medical School Hannover, Department of Hematology, Hemostasis, Oncology and Stem Cell Transplantation, Germany
| | - Lea A I Vaas
- Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig
| | - Margarete Zaborski
- Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig
| | - Hans G Drexler
- Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig
| | - Hilmar Quentmeier
- Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig
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25
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Liu C, Xing X, Chen L, Li D, Bai Q, Wang Q, Yu H, Zeng X, Wei Q, Gao C, Zhang Z, Zhang J, He Z, Ma L, Li J, Duan H, Zheng Y, Xiao Y, Chen W. Specific histone modifications regulate the expression of AhR in 16HBE cells exposed to benzo(a)pyrene. Toxicol Res (Camb) 2015. [DOI: 10.1039/c4tx00088a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Our study identified specific histone modifications that were involved in down regulation of the transcription of AhR, conferring cells resistance to cellular damage.
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26
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Chang CC, Sue YM, Yang NJ, Lee YH, Juan SH. 3-Methylcholanthrene, an AhR agonist, caused cell-cycle arrest by histone deacetylation through a RhoA-dependent recruitment of HDAC1 and pRb2 to E2F1 complex. PLoS One 2014; 9:e92793. [PMID: 24658119 PMCID: PMC3962457 DOI: 10.1371/journal.pone.0092793] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 02/25/2014] [Indexed: 12/15/2022] Open
Abstract
We previously showed that treating vascular endothelial cells with 3-methylcholanthrene (3MC) caused cell-cycle arrest in the Go/G1 phase; this resulted from the induction of p21 and p27 and a decreased level and activity of the cyclin-dependent kinase, Cdk2. We further investigated the molecular mechanisms that modulate cell-cycle regulatory proteins through the aryl-hydrocarbon receptor (AhR)/Ras homolog gene family, member A (RhoA) dependent epigenetic modification of histone. AhR/RhoA activation mediated by 3MC was essential for the upregulation of retinoblastoma 2 (pRb2) and histone deacetylase 1 (HDAC1), whereas their nuclear translocation was primarily modulated by RhoA activation. The combination of increased phosphatase and tensin homolog (PTEN) activity and decreased phosphatidylinositide 3-kinase (PI3K) activation by 3MC led to the inactivation of the Ras-cRaf pathway, which contributed to pRb2 hypophosphorylation. Increased HDAC1/pRb2 recruitment to the E2F1 complex decreased E2F1-transactivational activity and H3/H4 deacetylation, resulting in the downregulation of cell-cycle regulatory proteins (Cdk2/4 and Cyclin D3/E). Co-immunoprecipitation and electrophoretic mobility shift assay (EMSA) results showed that simvastatin prevented the 3MC-increased binding activities of E2F1 proteins in their promoter regions. Additionally, RhoA inhibitors (statins) reversed the effect of 3MC in inhibiting DNA synthesis by decreasing the nuclear translocation of pRb2/HDAC1, leading to a recovery of the levels of cell-cycle regulatory proteins. In summary, 3MC decreased cell proliferation by the epigenetic modification of histone through an AhR/RhoA-dependent mechanism that can be rescued by statins.
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Affiliation(s)
- Chih-Cheng Chang
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
| | - Yuh-Mou Sue
- Department of Nephrology, Taipei Medical University-Wan Fang Hospital, Taipei, Taiwan
| | - Nian-Jie Yang
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
| | - Yi-Hsuan Lee
- Institute of Physiology, National Yang-Ming University, Taipei, Taiwan
| | - Shu-Hui Juan
- Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
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27
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Teino I, Matvere A, Kuuse S, Ingerpuu S, Maimets T, Kristjuhan A, Tiido T. Transcriptional repression of the Ahr gene by LHCGR signaling in preovulatory granulosa cells is controlled by chromatin accessibility. Mol Cell Endocrinol 2014; 382:292-301. [PMID: 24145128 DOI: 10.1016/j.mce.2013.10.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 09/08/2013] [Accepted: 10/11/2013] [Indexed: 01/22/2023]
Abstract
Recent advances in establishing the role of the aryl hydrocarbon receptor (Ahr) in normophysiology have discovered its fundamental role, amongst others, in female reproduction. Considering previous studies suggesting the hormonal modulation of Ahr, we aimed to investigate whether in murine granulosa cells (GCs) the gonadotropins regulate Ahr expression and how this is mechanistically implemented. We found that the FSH-like substance--pregnant mare serum gonadotropin--led to stimulation of Ahr expression. More importantly hCG produced relatively rapid reduction of Ahr mRNA in GCs of preovulatory follicles. We show for the first time that LHCGR signaling in regulating the Ahr message involves protein kinase A pathway and is attributable to decreased transcription rate. Finally, we found that Ahr promoter accessibility was decreased by hCG, implicating chromatin remodeling in Ahr gene regulation by LH.
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Affiliation(s)
- Indrek Teino
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Antti Matvere
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Sulev Kuuse
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Sulev Ingerpuu
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Toivo Maimets
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Arnold Kristjuhan
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia
| | - Tarmo Tiido
- Department of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia.
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28
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Englert NA, Turesky RJ, Han W, Bessette EE, Spivack SD, Caggana M, Spink DC, Spink BC. Genetic and epigenetic regulation of AHR gene expression in MCF-7 breast cancer cells: role of the proximal promoter GC-rich region. Biochem Pharmacol 2012; 84:722-35. [PMID: 22728919 DOI: 10.1016/j.bcp.2012.06.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 06/14/2012] [Accepted: 06/14/2012] [Indexed: 10/28/2022]
Abstract
The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, contributes to carcinogenesis through its role in the regulation of cytochrome P450 1 (CYP1)-catalyzed metabolism of carcinogens. Here, we investigated genetic and epigenetic mechanisms that affect AhR expression. Analyses of the human AHR proximal promoter in MCF-7 human breast cancer cells using luciferase assays and electrophoretic mobility shift assays revealed multiple specificity protein (Sp) 1 binding sequences that are transcriptional activators in vitro. The regulation of AhR expression was evaluated in long-term estrogen exposed (LTEE) MCF-7 cells, which showed increased AhR expression, enhanced CYP1 inducibility, and increased capacity to form DNA adducts when exposed to the dietary carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine. The increased AhR expression in LTEE cells was found not to result from increased mRNA stability, differential RNA processing, or decreased DNA methylation. Analysis of the AHR proximal promoter region using chromatin immunoprecipitation confirmed that enhanced expression of AhR in LTEE cells involves changes in histone modifications, notably decreased trimethylation of histone 3, lysine 27. Upon further examination of the GC-rich Sp1-binding region, we confirmed that it contains a polymorphic (GGGGC)(n) repeat. In a population of newborns from New York State, the allele frequency of (GGGGC)(n) was n = 4 > 5 ≫ 6, 2. Circular dichroism spectroscopy revealed the ability of sequences of this GC-rich region to form guanine-quadruplex structures in vitro. These studies revealed multiple levels at which AhR expression may be controlled, and offer additional insights into mechanisms regulating AhR expression that can ultimately impact carcinogenesis.
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Affiliation(s)
- Neal A Englert
- Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
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29
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Abel J, Haarmann-Stemmann T. An introduction to the molecular basics of aryl hydrocarbon receptor biology. Biol Chem 2011; 391:1235-48. [PMID: 20868221 DOI: 10.1515/bc.2010.128] [Citation(s) in RCA: 208] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Depending on their chemical structure and properties, environmental chemicals and other xenobiotics that enter the cell can affect cellular function by either nonselective binding to cellular macromolecules or by interference with cellular receptors, which would initiate a more defined cell biological response. One of these intracellular chemosensor molecules is the aryl hydrocarbon receptor (AhR), a transcription factor of the bHLH/PAS family that is known to mediate the biochemical and toxic effects of dioxins, polyaromatic hydrocarbons and related compounds. Numerous investigations have revealed that the AhR is not only a master regulator of drug metabolism activated by anthropogenic chemicals, but is also triggered by natural and endogenous ligands and can influence cell biological endpoints such as growth and differentiation. Cutting-edge research has identified new intriguing functions of the AhR, such as during proteasomal degradation of steroid hormone receptors, the cellular UVB stress response and the differentiation of certain T-cell subsets. In this review we provide both a survey of the fundamental basics of AhR biology and an insight into new functional aspects of AhR signaling to further stimulate research on this intriguing transcription factor at the interface between toxicology, cell biology and immunology.
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Affiliation(s)
- Josef Abel
- Institut für Umweltmedizinische Forschung (IUF) an der Heinrich-Heine-Universität Düsseldorf gGmbH, Auf'm Hennekamp 50, Düsseldorf, Germany
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30
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Tang T, Lin X, Yang H, Zhou L, Wang Z, Shan G, Guo Z. Overexpression of antioxidant enzymes upregulates aryl hydrocarbon receptor expression via increased Sp1 DNA-binding activity. Free Radic Biol Med 2010; 49:487-92. [PMID: 20478378 PMCID: PMC2913407 DOI: 10.1016/j.freeradbiomed.2010.05.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 03/25/2010] [Accepted: 05/08/2010] [Indexed: 11/30/2022]
Abstract
We previously reported upregulation of aryl hydrocarbon receptor (AhR) expression as a mechanism by which overexpression of Cu/Zn-superoxide dismutase (SOD) and/or catalase accelerates benzo(a)pyrene (BaP) detoxification in mouse aorta endothelial cells (MAECs). The objective of this study was to investigate the regulatory role of specificity protein-1 (Sp1) in AhR expression in MAECs that overexpress Cu/Zn-SOD and/or catalase. Our data demonstrated comparable levels of nuclear Sp1 protein in the transgenic and wild-type MAECs; however, binding of Sp1 protein to the AhR promoter region was more than 2-fold higher in MAECs overexpressing Cu/Zn-SOD and/or catalase than in wild-type cells. Inhibition of Sp1 binding to the AhR promoter by mithramycin A reduced AhR expression and eliminated the differences between wild-type MAECs and three lines of transgenic cells. Functional promoter analysis indicated that AhR promoter activity was significantly higher in MAECs overexpressing catalase than in wild-type cells. Mutation of an AhR promoter Sp1-binding site or addition of hydrogen peroxide to the culture medium reduced AhR promoter activity, and decreased the differences between wild-type MAECs and transgenic cells overexpressing catalase. These results suggest that increased Sp1 binding to the AhR promoter region is an underlying mechanism for upregulation of AhR expression in MAECs that overexpress Cu/Zn-SOD and/or catalase.
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Affiliation(s)
- Tian Tang
- Department of Physiology, Meharry Medical College, Nashville, TN 37208
- Remin Hospital of Wuhan University, Wuhan 430060, PR China
| | - Xinghua Lin
- Department of Physiology, Meharry Medical College, Nashville, TN 37208
| | - Hong Yang
- Department of Physiology, Meharry Medical College, Nashville, TN 37208
| | - LiChun Zhou
- Department of Physiology, Meharry Medical College, Nashville, TN 37208
| | - Zefen Wang
- Department of Physiology, Meharry Medical College, Nashville, TN 37208
| | - Guang Shan
- Department of Physiology, Meharry Medical College, Nashville, TN 37208
- Remin Hospital of Wuhan University, Wuhan 430060, PR China
| | - ZhongMao Guo
- Department of Physiology, Meharry Medical College, Nashville, TN 37208
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31
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Wang Z, Yang H, Ramesh A, Roberts LJ, Zhou L, Lin X, Zhao Y, Guo Z. Overexpression of Cu/Zn-superoxide dismutase and/or catalase accelerates benzo(a)pyrene detoxification by upregulation of the aryl hydrocarbon receptor in mouse endothelial cells. Free Radic Biol Med 2009; 47:1221-9. [PMID: 19666105 PMCID: PMC2846758 DOI: 10.1016/j.freeradbiomed.2009.08.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 08/01/2009] [Indexed: 01/27/2023]
Abstract
A reduction in endogenously generated reactive oxygen species in vivo delays benzo(a)pyrene (BaP)-accelerated atherosclerosis, as revealed in hypercholesterolemic mice overexpressing Cu/Zn-superoxide dismutase (SOD) and/or catalase. To understand the molecular events involved in this protective action, we studied the effects of Cu/Zn-SOD and/or catalase overexpression on BaP detoxification and on aryl hydrocarbon receptor (AhR) expression and its target gene expression in mouse aortic endothelial cells (MAECs). Our data demonstrate that overexpression of Cu/Zn-SOD and/or catalase leads to an 18- to 20-fold increase in the expression of AhR protein in MAECs. After BaP exposure, the amount of AhR binding to the cytochrome P450 (CYP) 1A1 promoter was significantly greater, and the concentrations of BaP reactive intermediates were significantly less in MAECs overexpressing Cu/Zn-SOD and/or catalase than in wild-type cells. In addition, the BaP-induced CYP1A1 and 1B1 protein levels and BaP-elevated glutathione S-transferase (GST) activity were significantly higher in these transgenic cells, in parallel with elevated GSTp1, CYP1A1, and CYP1B1 mRNA levels, compared to wild-type MAECs. Moreover, knockdown of AhR with RNA interference diminished the Cu/Zn-SOD and catalase enhancement of CYP1A1 expression, GST activity, and BaP detoxification. These data demonstrate that overexpression of Cu/Zn-SOD and/or catalase is associated with upregulation of AhR and its target genes, such as xenobiotic-metabolizing enzymes.
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MESH Headings
- Animals
- Aorta/cytology
- Aorta/metabolism
- Aryl Hydrocarbon Hydroxylases/genetics
- Aryl Hydrocarbon Hydroxylases/metabolism
- Benzo(a)pyrene/pharmacokinetics
- Blotting, Western
- Catalase/metabolism
- Cells, Cultured
- Cytochrome P-450 CYP1A1/genetics
- Cytochrome P-450 CYP1A1/metabolism
- Cytochrome P-450 CYP1B1
- Endothelium, Vascular/cytology
- Endothelium, Vascular/metabolism
- F2-Isoprostanes/metabolism
- Furans/metabolism
- Glutathione Transferase/genetics
- Glutathione Transferase/metabolism
- Inactivation, Metabolic
- Mice
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Small Interfering/pharmacology
- Receptors, Aryl Hydrocarbon/antagonists & inhibitors
- Receptors, Aryl Hydrocarbon/genetics
- Receptors, Aryl Hydrocarbon/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Superoxide Dismutase/metabolism
- Up-Regulation
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Affiliation(s)
- Zefen Wang
- Department of Cardiovascular Biology, Meharry Medical College, Nashville, TN 37208, USA
| | - Hong Yang
- Department of Cardiovascular Biology, Meharry Medical College, Nashville, TN 37208, USA
- Corresponding author. Fax: +1 615 321 2949. (H. Yang), (Z. Guo)
| | - Aramandla Ramesh
- Department of Cancer Biology, Meharry Medical College, Nashville, TN 37208, USA
| | - L. Jackson Roberts
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
| | - LiChun Zhou
- Department of Cardiovascular Biology, Meharry Medical College, Nashville, TN 37208, USA
| | - Xinhua Lin
- Department of Cardiovascular Biology, Meharry Medical College, Nashville, TN 37208, USA
| | - Yanfeng Zhao
- Department of Cardiovascular Biology, Meharry Medical College, Nashville, TN 37208, USA
| | - ZhongMao Guo
- Department of Cardiovascular Biology, Meharry Medical College, Nashville, TN 37208, USA
- Corresponding author. Fax: +1 615 321 2949. (H. Yang), (Z. Guo)
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32
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Dewa Y, Nishimura J, Jin M, Kawai M, Saegusa Y, Harada T, Shibutani M, Mitsumori K. Molecular Expression Analysis of β-Naphthoflavone-induced Hepatocellular Tumors in Rats. Toxicol Pathol 2009; 37:446-55. [DOI: 10.1177/0192623309335062] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The present study was performed to characterize molecular expression levels of preneoplastic and neoplastic lesions induced by β-naphthoflavone (BNF), an aryl hydrocarbon receptor (AhR) agonist in rat hepatocarcinogenesis. Male F344 rats were initiated with an intraperitoneal injection of 200 mg/kg N-diethylnitrosamine, and two weeks later, they were fed a diet containing 0% or 1% BNF for twenty-eight weeks. All animals were subjected to a two-thirds partial hepatectomy at week 3 and sacrificed at week 30. Histopathologically, BNF increased the incidence and multiplicity of altered foci (1.7-fold and 3.3-fold) and hepatocellular adenomas (HCAs) (4.0-fold and 4.7-fold). Immunohistochemically, BNF increased the number of proliferating cell nuclear antigen (PCNA)-positive cells in altered foci (2.3-fold) and HCAs (6.7-fold) compared with the surrounding tissue and decreased the staining of cell cycle regulators (P21, C/EBPα). In addition, loss of reactivity for AhR-regulated (CYP1A1, CYP1B1) molecules and increased reactivity of Nrf-2-regulated (AKR7, GPX2) molecules were also observed in proliferative lesions. Furthermore, increased staining of histone deacetylase (HDAC1) in the nucleus was prominent in HCAs. The differential expression patterns were confirmed at mRNA levels by real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis. These results suggest that enhanced cell proliferation and protection against oxidative stress play an important role in BNF-induced hepatocarcinogenesis in rats.
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Affiliation(s)
- Yasuaki Dewa
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, Tokyo, Japan
- Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Jihei Nishimura
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, Tokyo, Japan
- Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Meilan Jin
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, Tokyo, Japan
- Department of Applied Biological Science, United Graduate School of Agricultural Sciences, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Masaomi Kawai
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, Tokyo, Japan
- Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Yukie Saegusa
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, Tokyo, Japan
- Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Tomoaki Harada
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Makoto Shibutani
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Kunitoshi Mitsumori
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, Tokyo, Japan
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Bielefeld KA, Lee C, Riddick DS. Regulation of aryl hydrocarbon receptor expression and function by glucocorticoids in mouse hepatoma cells. Drug Metab Dispos 2007; 36:543-51. [PMID: 18086832 DOI: 10.1124/dmd.107.019703] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that mediates most biological responses to 2,3, 7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related aromatic hydrocarbons. Although the role of the AHR in control of drug metabolism and endocrine disruption is partly understood, we know little about the regulation of the AHR itself by endocrine factors. Our work with hypophysectomized rats suggested that hepatic AHR protein level is positively regulated by pituitary-dependent factors. A current hypothesis is that adrenal glucocorticoids elevate AHR expression and enhance responsiveness to AHR agonists. Dexamethasone (DEX) at concentrations that activate the glucocorticoid receptor (GR) increased AHR mRNA, protein, and TCDD-binding by approximately 50% in Hepa-1 mouse hepatoma cells. This response was blocked by the GR antagonist 17beta-hydroxy-11beta-[4-dimethylamino phenyl]-17alpha-[1-propynyl]estra-4,9-dien-3-one (RU486), suggesting GR involvement. This small magnitude increase in AHR levels was functionally significant; pretreatment of Hepa-1 cells with DEX caused a 75% increase in the maximum induction of an AHR-activated luciferase reporter plasmid by TCDD. A luciferase reporter under control of the proximal 2.5 kilobases of the mouse Ahr 5'-flanking region and promoter was induced approximately 2.5-fold by DEX when cotransfected with a mouse GR expression plasmid. This is the first demonstration that glucocorticoids increase AHR levels in hepatoma cells via a GR-dependent transcriptional mechanism, suggesting a novel aspect of cross-talk between the AHR and the GR.
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Affiliation(s)
- Kirsten A Bielefeld
- Department of Pharmacology and Toxicology, Medical Sciences Building, University of Toronto, Toronto, ON, Canada M5S 1A8
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Hooven LA, Mahadevan B, Keshava C, Johns C, Pereira C, Desai D, Amin S, Weston A, Baird WM. Effects of suberoylanilide hydroxamic acid and trichostatin A on induction of cytochrome P450 enzymes and benzo[a]pyrene DNA adduct formation in human cells. Bioorg Med Chem Lett 2005; 15:1283-7. [PMID: 15713371 DOI: 10.1016/j.bmcl.2005.01.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2004] [Revised: 01/12/2005] [Accepted: 01/14/2005] [Indexed: 12/31/2022]
Abstract
In this study, we investigated the effects of histone deacetylase (HDAC) inhibitors suberoylanilide hydroxamic acid (SAHA) and trichostatin A (TSA) on the metabolism of polycyclic aromatic hydrocarbons (PAH) in human mammary carcinoma derived MCF-7 cells in culture. Benzo[a]pyrene (B[a]P) induces cytochrome P450 (CYP) 1A1, CYP1B1 and other xenobiotic metabolizing enzymes. Results from our study indicated a significant increase in CYP activity in comparison to vehicle control in cells treated with SAHA or TSA as measured by ethoxyresorufin-O-deethylase assay. However, co-treatment with 1.0 microM SAHA and BP, reduced the mRNA levels of CYP1B1 relative to B[a]P alone. When co-treated with 1.0 microM TSA and BP, a reduction in the mRNA levels of both CYP1A1 and CYP1B1 was observed relative to BP alone. We further investigated to ascertain if the differential expression and activity of CYP1A1 and CYP1B1 influenced levels of B[a]P DNA adduct formation. MCF-7 cells co-treated with B[a]P and SAHA or TSA formed DNA adducts, although no significant differences in levels of DNA binding were revealed. These results suggest that while CYP enzyme activity and gene expression were affected by the HDAC inhibitors SAHA and TSA, they had no apparent influence on B[a]P DNA binding.
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Affiliation(s)
- Louisa A Hooven
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
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35
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Boutros PC, Moffat ID, Franc MA, Tijet N, Tuomisto J, Pohjanvirta R, Okey AB. Dioxin-responsive AHRE-II gene battery: identification by phylogenetic footprinting. Biochem Biophys Res Commun 2004; 321:707-15. [PMID: 15358164 DOI: 10.1016/j.bbrc.2004.06.177] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2004] [Indexed: 11/29/2022]
Abstract
We identified a set of genes that respond to dioxins through the recently discovered AHRE-II ("XRE-II") enhancer element. A total of 36 genes containing AHRE-II motifs conserved across human, mouse, and rat gene orthologs were identified by genome-wide transcription-factor binding-site searches and phylogenetic footprinting. Microarray experiments on liver from rats treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin revealed statistically significant changes in mRNA levels for 13 of these 36 genes after three hours and 15 genes after 19h. The set of responsive genes was functionally characterized by ontological analysis and found to be enriched in ion-channels and transporters. Our identification of 36 putatively AHRE-II-regulated genes highlights the regulatory versatility of the aryl hydrocarbon receptor (AHR) and the ability of the AHR and its dimerization partner, ARNT, to act both as a ligand-activated transcription-factor (on AHRE-I) and as a ligand-activated coactivator (on AHRE-II). Collectively, these results demonstrate that the AHRE-II induction mechanism is employed by multiple genes and provide the first categorization of the gene battery of a ligand-activated coactivator.
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Affiliation(s)
- Paul C Boutros
- Department of Pharmacology, University of Toronto, Toronto, Ont., Canada M5S 1A8
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36
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Ullerås E, Miller SJ, Adam GI, Kanduri C, Wilcock AC, Franklin GC. Inhibition of histone deacetylase activity causes cell type-specific induction of the PDGF-B promoter only in the absence of activation by its enhancer. Exp Cell Res 2001; 270:188-98. [PMID: 11640883 DOI: 10.1006/excr.2001.5338] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There is a strong correlation between the acetylation status of nucleosomal histones and transcriptional activity. Here we show that the histone deacetylase inhibitor trichostatin A (TSA) activates reporter gene constructs driven by the human platelet-derived growth factor B (PDGF-B) gene promoter. This activation showed an inverse correlation with the cell type-specific transcriptional activities of the promoter. The TSA response was minimal in three tumor cell lines that exhibit high-level promoter activity. In JEG-3 choriocarcinoma cells, however, where the basal promoter activity is considerably lower, there was a strong response to TSA. This was in contrast to constructs that included a PDGF-B enhancer, which were refractory to TSA effects, indicating a possible function of the enhancer in modulating acetylation status. Analysis of PDGF-B promoter mutants with respect to TSA induction revealed no specific TSA-responsive element, but suggested that association of nonacetylated histones to the PDGF-B promoter may be a default process in the absence of enhancer activation. TSA treatment of JEG-3 cells, either alone or in combination with the demethylating agent 5-azacytidine, failed to activate the silenced endogenous PDGF-B transcript, however, which appears to be repressed by additional mechanisms.
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Affiliation(s)
- E Ullerås
- Department of Animal Development and Genetics, Evolution Biology Centre, Uppsala University, Norbyvägen 18A, Uppsala, SE-752 36, Sweden.
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Wolff S, Harper PA, Wong JM, Mostert V, Wang Y, Abel J. Cell-specific regulation of human aryl hydrocarbon receptor expression by transforming growth factor-beta(1). Mol Pharmacol 2001; 59:716-24. [PMID: 11259615 DOI: 10.1124/mol.59.4.716] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Previous studies showed that TGF-beta down-regulates aryl hydrocarbon (AhR) expression in human lung carcinoma cells A549. Here we analyzed the molecular mechanisms by which TGF-beta modulates AhR expression. A 5799-nucleotide 5'-flanking region of human AhR gene was isolated. Transient transfection studies of full-length (hAhRP) and deletion promoter constructs indicate the requirement of a cis-regulatory element encompassing -1980 to -1892 for full constitutive activity. Basal hAhRP activity occurs in a cell-specific manner; human hepatoma HepG2 cells possess a 10-fold higher activity compared with A549 cells. TGF-beta exerts cell-specific effects on hAhRP activity. Treatment of cells with 100 pM TGF-beta leads to a 50% inhibition in A549 and a 3-fold induction in HepG2 cells. Deletion mutagenesis identified a TGF-beta-responsive sequence containing a functional conserved Smad-binding element. Transient overexpression of Smad 2, 3, and 4 indicates that these signal transducers modulate hAhRP activity. The down-regulation of AhR by TGF-beta is modulated by 5'-TG-3'-interacting factor (TGIF). Transient overexpression of TGIF in MDA-MB231 and HepG2 cells led to inhibition of hAhRP activity and a similar decrease of AhR mRNA expression. Our findings indicate that Smad proteins are involved in the cell-specific regulation of AhR expression by TGF-beta.
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MESH Headings
- 5' Untranslated Regions/genetics
- Activin Receptors, Type I
- Binding Sites/genetics
- Carcinoma/genetics
- Carcinoma/metabolism
- DNA-Binding Proteins/metabolism
- Dose-Response Relationship, Drug
- Down-Regulation/drug effects
- Homeodomain Proteins/metabolism
- Humans
- Liver Neoplasms/genetics
- Liver Neoplasms/metabolism
- Lung Neoplasms/genetics
- Lung Neoplasms/metabolism
- Mutagenesis, Site-Directed
- Protein Serine-Threonine Kinases/metabolism
- RNA, Messenger/metabolism
- Receptor, Transforming Growth Factor-beta Type I
- Receptors, Aryl Hydrocarbon/genetics
- Receptors, Aryl Hydrocarbon/metabolism
- Receptors, Transforming Growth Factor beta/metabolism
- Regulatory Sequences, Nucleic Acid/genetics
- Repressor Proteins
- Smad2 Protein
- Smad3 Protein
- Smad4 Protein
- Trans-Activators/metabolism
- Transfection
- Transforming Growth Factor beta/pharmacology
- Tumor Cells, Cultured
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Affiliation(s)
- S Wolff
- Department of Experimental Toxicology, Medical Institute of Environmental Hygiene at the Heinrich-Heine-University, Düsseldorf, Germany
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Wu W, Kocarek TA, Runge-Morris M. Sex-dependent regulation by dexamethasone of murine hydroxysteroid sulfotransferase gene expression. Toxicol Lett 2001; 119:235-46. [PMID: 11246177 DOI: 10.1016/s0378-4274(01)00263-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
To determine whether glucocorticoid-inducible expression of hepatic hydroxysteroid sulfotransferase is conserved in mouse, the effects of dexamethasone (DEX) on hydroxysteroid sulfotransferase (mSULT2A) gene expression were investigated in primary cultured hepatocytes prepared from C57BL/6J mice. In female mouse hepatocytes, DEX (10(-7) and 10(-5) M, respectively) produced 8.2- and 17.8-fold increases, respectively, in the amounts of mSULT2A mRNA relative to control. By contrast, mSULT2A mRNA levels were undetectable in male mouse hepatocytes. Female-predominant mSULT2A mRNA expression was also observed in liver samples from C57BL/6J and three other mouse strains. Treatment of primary cultured female mouse hepatocytes with dihydrotestosterone in the presence of DEX suppressed mSULT2 expression. Transfection of primary cultured male or female mouse hepatocytes with a rat SULT2-40/41 reporter construct revealed that hepatocytes of both sexes have sufficient machinery to achieve DEX-inducible SULT2 transcription. However, treatment with the potent histone deacetylase inhibitor trichostatin A failed to elicit mSULT2A expression in male mouse hepatocytes.
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Affiliation(s)
- W Wu
- Institute of Environmental Health Sciences, Wayne State University, 2727 Second Avenue, Detroit, MI 48201, USA
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