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Kodzhahinchev V, Rachamalla M, Al-Dissi A, Niyogi S, Weber LP. Examining the subchronic (28-day) effects of aqueous Cd-BaP co-exposure on detoxification capacity and cardiac function in adult zebrafish (Danio rerio). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2023; 263:106672. [PMID: 37672889 DOI: 10.1016/j.aquatox.2023.106672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 08/15/2023] [Accepted: 08/25/2023] [Indexed: 09/08/2023]
Abstract
The present study aimed to examine the effects of environmentally relevant concentrations of cadmium (Cd) and Benzo[a]Pyrene (BaP) in the adult zebrafish (Danio rerio). To this end, fish were exposed to either 1 or 10 μg/L Cd or 0.1 or 1 μg/L BaP in isolation, or a co-exposure containing a mixture of the two toxicants. Our results showed extensive modulation of the expression of key antioxidant genes (GPx, SOD1, catalase), detoxifying genes (MT1, MT2, CYP1A1) and a stress biomarker (HSP70) differing between control, single toxicant groups and co-exposure groups. We additionally carried out histopathological analysis of the gills, liver, and hearts of exposed animals, noting no differences in tissue necrosis or apoptosis. Finally, we carried out ultrasonographic analysis of cardiac function, noting a significant decrease of E-wave peak velocity and end diastolic volume in exposed fish. This in turn was accompanied by a decrease in stroke volume and ejection fraction, but not cardiac output in co-exposed fish. The present study is the first to demonstrate that a subchronic aqueous exposure to a Cd-BaP mixture can extensively modulate detoxification capacity and cardiac function in adult zebrafish in a tissue-specific manner.
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Affiliation(s)
| | - Mahesh Rachamalla
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Ahmad Al-Dissi
- Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Som Niyogi
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada; Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada
| | - Lynn P Weber
- Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada; Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK, Canada
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Baltazar P, de Melo Junior AF, Fonseca NM, Lança MB, Faria A, Sequeira CO, Teixeira-Santos L, Monteiro EC, Campos Pinheiro L, Calado J, Sousa C, Morello J, Pereira SA. Oxalate (dys)Metabolism: Person-to-Person Variability, Kidney and Cardiometabolic Toxicity. Genes (Basel) 2023; 14:1719. [PMID: 37761859 PMCID: PMC10530622 DOI: 10.3390/genes14091719] [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: 06/25/2023] [Revised: 08/11/2023] [Accepted: 08/16/2023] [Indexed: 09/29/2023] Open
Abstract
Oxalate is a metabolic end-product whose systemic concentrations are highly variable among individuals. Genetic (primary hyperoxaluria) and non-genetic (e.g., diet, microbiota, renal and metabolic disease) reasons underlie elevated plasma concentrations and tissue accumulation of oxalate, which is toxic to the body. A classic example is the triad of primary hyperoxaluria, nephrolithiasis, and kidney injury. Lessons learned from this example suggest further investigation of other putative factors associated with oxalate dysmetabolism, namely the identification of precursors (glyoxylate, aromatic amino acids, glyoxal and vitamin C), the regulation of the endogenous pathways that produce oxalate, or the microbiota's contribution to oxalate systemic availability. The association between secondary nephrolithiasis and cardiovascular and metabolic diseases (hypertension, type 2 diabetes, and obesity) inspired the authors to perform this comprehensive review about oxalate dysmetabolism and its relation to cardiometabolic toxicity. This perspective may offer something substantial that helps advance understanding of effective management and draws attention to the novel class of treatments available in clinical practice.
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Affiliation(s)
- Pedro Baltazar
- Centro Hospitalar Universitário de Lisboa Central, E.P.E, 1150-199 Lisboa, Portugal; (P.B.); (N.M.F.); (M.B.L.); (L.C.P.); (J.C.)
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
| | - Antonio Ferreira de Melo Junior
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
| | - Nuno Moreira Fonseca
- Centro Hospitalar Universitário de Lisboa Central, E.P.E, 1150-199 Lisboa, Portugal; (P.B.); (N.M.F.); (M.B.L.); (L.C.P.); (J.C.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
| | - Miguel Brito Lança
- Centro Hospitalar Universitário de Lisboa Central, E.P.E, 1150-199 Lisboa, Portugal; (P.B.); (N.M.F.); (M.B.L.); (L.C.P.); (J.C.)
| | - Ana Faria
- CHRC, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal;
| | - Catarina O. Sequeira
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
| | - Luísa Teixeira-Santos
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
| | - Emilia C. Monteiro
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
| | - Luís Campos Pinheiro
- Centro Hospitalar Universitário de Lisboa Central, E.P.E, 1150-199 Lisboa, Portugal; (P.B.); (N.M.F.); (M.B.L.); (L.C.P.); (J.C.)
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
| | - Joaquim Calado
- Centro Hospitalar Universitário de Lisboa Central, E.P.E, 1150-199 Lisboa, Portugal; (P.B.); (N.M.F.); (M.B.L.); (L.C.P.); (J.C.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
- ToxOmics, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal
| | - Cátia Sousa
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
| | - Judit Morello
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
| | - Sofia A. Pereira
- iNOVA4Health, NOVA Medical School|Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, 1150-082 Lisboa, Portugal; (A.F.d.M.J.); (C.O.S.); (L.T.-S.); (E.C.M.); (C.S.); (J.M.)
- Centro Clínico Académico de Lisboa, 1159-056 Lisboa, Portugal
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3
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Sondermann NC, Faßbender S, Hartung F, Hätälä AM, Rolfes KM, Vogel CFA, Haarmann-Stemmann T. Functions of the aryl hydrocarbon receptor (AHR) beyond the canonical AHR/ARNT signaling pathway. Biochem Pharmacol 2023; 208:115371. [PMID: 36528068 PMCID: PMC9884176 DOI: 10.1016/j.bcp.2022.115371] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022]
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor regulating adaptive and maladaptive responses toward exogenous and endogenous signals. Research from various biomedical disciplines has provided compelling evidence that the AHR is critically involved in the pathogenesis of a variety of diseases and disorders, including autoimmunity, inflammatory diseases, endocrine disruption, premature aging and cancer. Accordingly, AHR is considered an attractive target for the development of novel preventive and therapeutic measures. However, the ligand-based targeting of AHR is considerably complicated by the fact that the receptor does not always follow the beaten track, i.e. the canonical AHR/ARNT signaling pathway. Instead, AHR might team up with other transcription factors and signaling molecules to shape gene expression patterns and associated physiological or pathophysiological functions in a ligand-, cell- and micromilieu-dependent manner. Herein, we provide an overview about some of the most important non-canonical functions of AHR, including crosstalk with major signaling pathways involved in controlling cell fate and function, immune responses, adaptation to low oxygen levels and oxidative stress, ubiquitination and proteasomal degradation. Further research on these diverse and exciting yet often ambivalent facets of AHR biology is urgently needed in order to exploit the full potential of AHR modulation for disease prevention and treatment.
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Affiliation(s)
- Natalie C Sondermann
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Sonja Faßbender
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Frederick Hartung
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Anna M Hätälä
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Katharina M Rolfes
- IUF - Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Christoph F A Vogel
- Department of Environmental Toxicology and Center for Health and the Environment, University of California, Davis, CA 95616, USA
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4
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Amine ZE, Mauger JF, Imbeault P. CYP1A1, VEGFA and Adipokine Responses of Human Adipocytes Co-exposed to PCB126 and Hypoxia. Cells 2022; 11:cells11152282. [PMID: 35892579 PMCID: PMC9331964 DOI: 10.3390/cells11152282] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 11/16/2022] Open
Abstract
It is increasingly recognized that hypoxia may develop in adipose tissue as its mass expands. Adipose tissue is also the main reservoir of lipophilic pollutants, including polychlorinated biphenyls (PCBs). Both hypoxia and PCBs have been shown to alter adipose tissue functions. The signaling pathways induced by hypoxia and pollutants may crosstalk, as they share a common transcription factor: aryl hydrocarbon receptor nuclear translocator (ARNT). Whether hypoxia and PCBs crosstalk and affect adipokine secretion in human adipocytes remains to be explored. Using primary human adipocytes acutely co-exposed to different levels of hypoxia (24 h) and PCB126 (48 h), we observed that hypoxia significantly inhibits the PCB126 induction of cytochrome P450 (CYP1A1) transcription in a dose-response manner, and that Acriflavine (ACF)—an HIF1α inhibitor—partially restores the PCB126 induction of CYP1A1 under hypoxia. On the other hand, exposure to PCB126 did not affect the transcription of the vascular endothelial growth factor-A (VEGFA) under hypoxia. Exposure to hypoxia increased leptin and interleukin-6 (IL-6), and decreased adiponectin levels dose-dependently, while PCB126 increased IL-6 and IL-8 secretion in a dose-dependent manner. Co-exposure to PCB126 and hypoxia did not alter the adipokine secretion pattern observed under hypoxia and PCB126 exposure alone. In conclusion, our results indicate that (1) hypoxia inhibits PCB126-induced CYP1A1 expression at least partly through ARNT-dependent means, suggesting that hypoxia could affect PCB metabolism and toxicity in adipose tissue, and (2) hypoxia and PCB126 affect leptin, adiponectin, IL-6 and IL-8 secretion differently, with no apparent crosstalk between the two factors.
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Affiliation(s)
- Zeinab El Amine
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (Z.E.A.); (J.-F.M.)
| | - Jean-François Mauger
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (Z.E.A.); (J.-F.M.)
| | - Pascal Imbeault
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (Z.E.A.); (J.-F.M.)
- Institut du Savoir Montfort, Hôpital Montfort, Ottawa, ON K1K 0T2, Canada
- Correspondence: ; Tel.: +1-(613)-562-5800-(7290)
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5
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Kim HG, Han EH, Im JH, Lee EJ, Jin SW, Jeong HG. Caffeic acid phenethyl ester inhibits 3-MC-induced CYP1A1 expression through induction of hypoxia-inducible factor-1α. Biochem Biophys Res Commun 2015; 465:562-8. [PMID: 26296470 DOI: 10.1016/j.bbrc.2015.08.060] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 08/13/2015] [Indexed: 01/25/2023]
Abstract
Caffeic acid phenethyl ester (CAPE), a natural component of propolis, is reported to have anticarcinogenic properties, although its precise chemopreventive mechanism remains unclear. In this study, we examined the effects of CAPE on 3-methylcholanthrene (3-MC)-induced CYP1A1 expression and activities. CAPE reduced the formation of the benzo[a]pyrene-DNA adduct. Moreover, CAPE inhibited 3-MC-induced CYP1A1 activity, mRNA expression, protein level, and promoter activity. CAPE treatment also decreased 3-MC-inducible xenobiotic-response element (XRE)-linked luciferase, aryl hydrocarbons receptor (AhR) transactivation and nuclear localization. CAPE induced hypoxia inducible factor-1α (HIF-1α) protein level and HIF-1α responsible element (HRE) transcriptional activity. CAPE-mediated HIF-1α reduced 3-MC-inducible CYP1A1 protein expression. Taken together, CAPE decreases 3-MC-mediated CYP1A1 expression, and this inhibitory response is associated with inhibition of AhR and HIF-1α induction.
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Affiliation(s)
- Hyung Gyun Kim
- Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, South Korea
| | - Eun Hee Han
- Division of Life Science, Korea Basic Science Institute, Daejeon, South Korea
| | - Ji Hye Im
- Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, South Korea
| | - Eun Ji Lee
- Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, South Korea
| | - Sun Woo Jin
- Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, South Korea
| | - Hye Gwang Jeong
- Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, South Korea.
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6
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Benedetti M, Giuliani ME, Regoli F. Oxidative metabolism of chemical pollutants in marine organisms: molecular and biochemical biomarkers in environmental toxicology. Ann N Y Acad Sci 2015; 1340:8-19. [DOI: 10.1111/nyas.12698] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Maura Benedetti
- Dipartimento di Scienze della Vita e dell'Ambiente; Università Politecnica delle Marche; Ancona Italy
| | - Maria Elisa Giuliani
- Dipartimento di Scienze della Vita e dell'Ambiente; Università Politecnica delle Marche; Ancona Italy
| | - Francesco Regoli
- Dipartimento di Scienze della Vita e dell'Ambiente; Università Politecnica delle Marche; Ancona Italy
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7
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Gauthier PT, Norwood WP, Prepas EE, Pyle GG. Metal-PAH mixtures in the aquatic environment: a review of co-toxic mechanisms leading to more-than-additive outcomes. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 154:253-69. [PMID: 24929353 DOI: 10.1016/j.aquatox.2014.05.026] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 05/21/2014] [Accepted: 05/22/2014] [Indexed: 05/10/2023]
Abstract
Mixtures of metals and polycyclic aromatic hydrocarbons (PAHs) occur ubiquitously in aquatic environments, yet relatively little is known regarding their combined toxicities. Emerging reports investigating the additive mortality in metal-PAH mixtures have indicated that more-than-additive effects are equally as common as strictly-additive effects, raising concern for ecological risk assessment typically based on the summation of individual toxicities. Moreover, the current separation of focus between in vivo and in vitro studies, and fine- and coarse-scale endpoints, creates uncertainty regarding the mechanisms of co-toxicity involved in more-than-additive effects on whole organisms. Drawing from literature on metal and PAH toxicity in bacteria, protozoa, invertebrates, fish, and mammalian models, this review outlines several key mechanistic interactions likely to promote more-than-additive toxicity in metal-PAH mixtures. Namely, the deleterious effects of PAHs on membrane integrity and permeability to metals, the potential for metal-PAH complexation, the inhibitory nature of metals to the detoxification of PAHs via the cytochrome P450 pathway, the inhibitory nature of PAHs towards the detoxification of metals via metallothionein, and the potentiated production of reactive oxygenated species (ROS) in certain metal (e.g. Cu) and PAH (e.g., phenanthrenequinone) mixtures. Moreover, the mutual inhibition of detoxification suggests the possibility of positive feedback among these mechanisms. The individual toxicities and interactive aspects of contaminant transport, detoxification, and the production of ROS are herein discussed.
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Affiliation(s)
- Patrick T Gauthier
- Faculty of Natural Resources Management, Lakehead University, Thunder Bay, ON, Canada P7B 5E1.
| | - Warren P Norwood
- Aquatic Contaminants Research Division, Environment Canada, Burlington, ON, Canada L7R 4A6
| | - Ellie E Prepas
- Faculty of Natural Resources Management, Lakehead University, Thunder Bay, ON, Canada P7B 5E1
| | - Greg G Pyle
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada T1K 3M4
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Vorrink SU, Domann FE. Regulatory crosstalk and interference between the xenobiotic and hypoxia sensing pathways at the AhR-ARNT-HIF1α signaling node. Chem Biol Interact 2014; 218:82-8. [PMID: 24824450 DOI: 10.1016/j.cbi.2014.05.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 03/29/2014] [Accepted: 05/04/2014] [Indexed: 11/17/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates many of the responses to toxic environmental chemicals such as TCDD or dioxin-like PCBs. To regulate gene expression, the AhR requires its binding partner, the aryl hydrocarbon receptor nuclear translocator (ARNT). ARNT is also required by the hypoxia-inducible factor-1α (HIF-1α), a crucial regulator of responses to conditions of reduced oxygen. The important role of ARNT in both the AhR and HIF-1α signaling pathways establishes a meaningful foundation for a possible crosstalk between these two vitally important signaling pathways. This crosstalk might lead to interference between the two signaling pathways and thus might play a role in the variety of cellular responses after exposure to AhR ligands and reduced oxygen availability. This review focuses on studies that have analyzed the effect of low oxygen environments and hypoxia-mimetic agents on AhR signaling and conversely, the effect of AhR ligands, with a special emphasis on PCBs, on HIF-1α signaling. We highlight studies that assess the role of ARNT, elucidate the mechanism of the crosstalk, and discuss the physiological implications for exposure to AhR-inducing compounds in the context of hypoxia.
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Affiliation(s)
- Sabine U Vorrink
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA, USA; Department of Radiation Oncology, The University of Iowa, Iowa City, IA, USA
| | - Frederick E Domann
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA, USA; Department of Radiation Oncology, The University of Iowa, Iowa City, IA, USA.
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Hypoxia perturbs aryl hydrocarbon receptor signaling and CYP1A1 expression induced by PCB 126 in human skin and liver-derived cell lines. Toxicol Appl Pharmacol 2013; 274:408-16. [PMID: 24355420 DOI: 10.1016/j.taap.2013.12.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/27/2013] [Accepted: 12/05/2013] [Indexed: 11/21/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is an important mediator of toxic responses after exposure to xenobiotics including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and dioxin-like polychlorinated biphenyls (PCBs). Activation of AhR responsive genes requires AhR dimerization with the aryl hydrocarbon receptor nuclear translocator (ARNT), a heterodimeric partner also shared by the hypoxia-inducible factor-1α (HIF-1α) protein. TCDD-stimulated AhR transcriptional activity can be influenced by hypoxia; however, it less well known whether hypoxia interferes with AhR transcriptional transactivation in the context of PCB-mediated AhR activation in human cells. Elucidation of this interaction is important in liver hepatocytes which extensively metabolize ingested PCBs and experience varying degrees of oxygen tension during normal physiologic function. This study was designed to assess the effect of hypoxia on AhR transcriptional responses after exposure to 3,3',4,4',5-pentachlorobiphenyl (PCB 126). Exposure to 1% O2 prior to PCB 126 treatment significantly inhibited CYP1A1 mRNA and protein expression in human HepG2 and HaCaT cells. CYP1A1 transcriptional activation was significantly decreased upon PCB 126 stimulation under conditions of hypoxia. Additionally, hypoxia pre-treatment reduced PCB 126 induced AhR binding to CYP1 target gene promoters. Importantly, ARNT overexpression rescued cells from the inhibitory effect of hypoxia on XRE-luciferase reporter activity. Therefore, the mechanism of interference of the signaling crosstalk between the AhR and hypoxia pathways appears to be at least in part dependent on ARNT availability. Our results show that AhR activation and CYP1A1 expression induced by PCB 126 were significantly inhibited by hypoxia and hypoxia might therefore play an important role in PCB metabolism and toxicity.
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Key Words
- 2,2′,4,4′,5,5′-hexachlorobiphenyl
- 2,3,7,8-tetrachlorodibenzo-p-dioxin
- 3,3′,4,4′,5-pentachlorobiphenyl
- 6,2′,4′-trimethoxyflavone
- ARNT
- AhR
- CYP1A1
- ChIP
- DMSO
- EMSA
- HIF-1α
- HRE
- Hypoxia
- PCB
- PCB 126
- PCB 153
- RPLP0
- TCDD
- TMF
- XRE
- aryl hydrocarbon receptor
- aryl hydrocarbon receptor nuclear translocator
- bHLH/PAS
- basic helix-loop-helix/PER-ARNT-SIM
- chromatin immunoprecipitation
- cytochrome P450 1A1
- dimethyl sulfoxide
- electrophoretic mobility shift assay
- hypoxia response element
- hypoxia-inducible factor-1α
- polychlorinated biphenyl
- qRT-PCR
- quantitative real-time reverse transcription polymerase chain reaction
- ribosomal protein, large, P0
- xenobiotic response element
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10
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Fleming CR, Di Giulio RT. The role of CYP1A inhibition in the embryotoxic interactions between hypoxia and polycyclic aromatic hydrocarbons (PAHs) and PAH mixtures in zebrafish (Danio rerio). ECOTOXICOLOGY (LONDON, ENGLAND) 2011; 20:1300-14. [PMID: 21706407 PMCID: PMC4018733 DOI: 10.1007/s10646-011-0686-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/08/2011] [Indexed: 05/18/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants with elevated concentrations in waters that may also experience hypoxia. Previous research has shown interactions between hypoxia and some PAHs (fluoranthene, α-naphthoflavone) but no interaction with others (benzo[a]pyrene (BaP), β-naphthoflavone). Here we examine how hypoxia (7.4% oxygen, ~35% of normoxia) affects the embryotoxicity of PAHs that act through different mechanisms and the role that CYP1A inhibition may play in these interactions. About 500 μg/l BaP and 1-200 μg/l benzo[k]fluoranthene (BkF) interacted synergistically with hypoxia to induce pericardial edema in developing zebrafish (Danio rerio). Hypoxia protected from the embryotoxicity of pyrene (PY) and had no effect on the toxicity of polychlorinated biphenyl-126. Despite previous reports of other CYP1A inhibitors interacting with hypoxia, up to 2,000 μg/l dibenzothiophene, 2-aminoanthracene (AA), and carbazole (CB) all failed to induce embryotoxicity under normoxic or hypoxic conditions. The toxicity of PAH mixtures--including binary mixtures of BaP/AA and BaP/CB and two environmentally relevant, complex mixtures--were exacerbated severely by hypoxia to induce or worsen pericardial edema and cause mortality. The interactions between hypoxia and BkF and PY were closely mimicked by morpholino knockdown of CYP1A, indicating a potential role for metabolism of these compounds in their toxicity. Our results indicate that various PAHs may exhibit synergistic, antagonistic or additive toxicity with hypoxia. The enhanced toxicity of environmental mixtures of PAHs under hypoxia suggests that risk assessments that do not take into account potential interactions with hypoxia may underestimate the threat of PAHs to fish in contaminated sites.
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Affiliation(s)
- Carrie R Fleming
- Integrated Toxicology and Environmental Health Program, Nicholas School for the Environment and Earth Sciences, Duke University, Durham, NC, USA
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11
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Nakayama Wong LS, Aung HH, Lamé MW, Wegesser TC, Wilson DW. Fine particulate matter from urban ambient and wildfire sources from California's San Joaquin Valley initiate differential inflammatory, oxidative stress, and xenobiotic responses in human bronchial epithelial cells. Toxicol In Vitro 2011; 25:1895-905. [PMID: 21703343 DOI: 10.1016/j.tiv.2011.06.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 06/02/2011] [Accepted: 06/03/2011] [Indexed: 01/27/2023]
Abstract
Environmental particulate matter (PM) exposure has been correlated with pathogenesis of acute airway inflammatory disease such as asthma and COPD. PM size and concentration have been studied extensively, but the additional effects of particulate components such as biological material, transition metals, and polycyclic aromatic hydrocarbons could also impact initial disease pathogenesis. In this study, we compared urban ambient particulate matter (APM) collected from Fresno, California with wildfire (WF) particulate matter collected from Escalon, California on early transcriptional responses in human bronchial epithelial cells (HBE). Global gene expression profiling of APM treated HBE activated genes related to xenobiotic metabolism (CYP 1B1), endogenous ROS generation and response genes (DUOX1, SOD2, PTGS2) and pro-inflammatory responses associated with asthma or COPD such as IL-1α, IL-1β, IL-8, and CCL20. WF PM treatments also induced a pro-inflammatory gene response, but elicited a more robust xenobiotic metabolism and oxidative stress response. Inhibitor studies targeting endotoxin, ROS, and trace metals, found endotoxin inhibition had modest selective inhibition of inflammation while inhibition of hydrogen peroxide and transition metals had broad effects suggesting additional interactions with xenobiotic metabolism pathways. APM induced a greater inflammatory response while WF PM had more marked metabolism and ROS related responses.
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Affiliation(s)
- L S Nakayama Wong
- School of Veterinary Medicine, Department of Pathology, Microbiology, and Immunology, University of California, Davis, CA 95616, United States
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12
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Abdelhamid G, Anwar-Mohamed A, Badary OA, Moustafa AA, El-Kadi AO. Transcriptional and posttranscriptional regulation of CYP1A1 by vanadium in human hepatoma HepG2 cells. Cell Biol Toxicol 2010; 26:421-34. [DOI: 10.1007/s10565-010-9153-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Accepted: 02/05/2010] [Indexed: 01/24/2023]
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13
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Fleming CR, Billiard SM, Di Giulio RT. Hypoxia inhibits induction of aryl hydrocarbon receptor activity in topminnow hepatocarcinoma cells in an ARNT-dependent manner. Comp Biochem Physiol C Toxicol Pharmacol 2009; 150:383-9. [PMID: 19539049 PMCID: PMC3118667 DOI: 10.1016/j.cbpc.2009.06.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 06/06/2009] [Accepted: 06/07/2009] [Indexed: 10/20/2022]
Abstract
Hypoxic events often occur in waters contaminated with toxic chemicals, including agonists of the aryl hydrocarbon receptor (AhR). HIF-1alpha, the mediator of cellular responses to hypoxia, shares a dimerization partner (ARNT) with AhR and reciprocal crosstalk may occur. Studies addressing AhR/hypoxia crosstalk in mammalian cells have produced contradictory results regarding whether reciprocal crosstalk actually occurs between these pathways and the role ARNT plays in this interaction. We assessed hypoxia-AhR crosstalk in fish cells (PLHC-1) treated with hypoxia (1% O(2)) or normoxia (21% O(2)) and AhR agonists (benzo[a]pyrene (BaP), 3,3',4,4',5-pentachlorobiphenyl (PCB-126), and benzo[k]fluoranthene (BkF)) with and without overexpression of ARNT. Hypoxia limited the induction of a transiently transfected AhR reporter by all three of the AhR agonists; overexpression of ARNT eliminated this effect. PCB-126 had no effect on induction of a transiently transfected hypoxia reporter. BkF caused a minor increase in basal and induced hypoxia reporter activity. BaP decreased basal and induced hypoxia reporter activity; overexpression of ARNT did not alter this effect indicating that this interference with hypoxia pathway activity occurs through an alternate mechanism. Reduced hypoxia pathway activity with BaP treatment may be the result of a metabolite. This study supports the hypothesis that HIF-1alpha is able to sequester ARNT from AhR and limit the activity of the AhR pathway, but suggests that the converse is not true.
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Affiliation(s)
- Carrie R Fleming
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA.
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14
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Ascorbic acid suppresses the 2,3,7,8-tetrachloridibenxo-p-dioxin (TCDD)-induced CYP1A1 expression in human HepG2 cells. Toxicol In Vitro 2009; 23:622-6. [DOI: 10.1016/j.tiv.2009.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Revised: 02/02/2009] [Accepted: 02/22/2009] [Indexed: 11/18/2022]
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15
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Role of aryl hydrocarbon receptor in modulation of the expression of the hypoxia marker carbonic anhydrase IX. Biochem J 2009; 419:419-25. [PMID: 19154183 DOI: 10.1042/bj20080952] [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
Tumour-associated expression of CA IX (carbonic anhydrase IX) is to a major extent regulated by HIF-1 (hypoxia-inducible factor-1) which is important for transcriptional activation and consists of the oxygen-regulated subunit HIF-1alpha and the partner factor ARNT [AhR (aryl hydrocarbon receptor) nuclear translocator]. We have previously observed that HIF-1alpha competes with the AhR for interaction with ARNT under conditions when both conditionally regulated factors are activated. We have therefore investigated whether TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin)-induced activation of the AhR pathway might interfere with CA IX expression. The results from the present study suggest that TCDD treatment reduces hypoxic induction of both CA IX mRNA and protein expression. Moreover, the transcriptional activity of the CA9 promoter was significantly reduced by expression of CAAhR (constitutively active AhR), which activates transcription in a ligand-independent manner. Finally, we found that ARNT is critical for both hypoxic induction and the TCDD-mediated inhibition of CA9 expression.
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16
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Yu RMK, Ng PKS, Tan T, Chu DLH, Wu RSS, Kong RYC. Enhancement of hypoxia-induced gene expression in fish liver by the aryl hydrocarbon receptor (AhR) ligand, benzo[a]pyrene (BaP). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2008; 90:235-242. [PMID: 18945501 DOI: 10.1016/j.aquatox.2008.09.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Revised: 09/04/2008] [Accepted: 09/05/2008] [Indexed: 05/26/2023]
Abstract
Fish in polluted coastal habitats commonly suffer simultaneous exposure to both hypoxia and xenobiotics. Although the adaptive molecular responses to each stress have been described, little is known about the interaction between the signaling pathways mediating these responses. Previous studies in mammalian hepatoma cell lines have shown that hypoxia-inducible factor (HIF)- and/or aryl hydrocarbon receptor (AhR)-activated gene expression is suppressed following co-exposure to hypoxia and the hallmark AhR ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, whether similar crosstalk exists in the non-tumor liver tissues of fish and whether other non-TCDD ligands also play the same inhibitory role in this crosstalk remain unknown. Here, the in vivo hepatic mRNA expression profiles of multiple hypoxia- and AhR-responsive genes (later gene expression=mRNA expression of the gene) were examined in the orange-spotted grouper (Epinephelus coioides) upon single and combined exposures to hypoxia and benzo[a]pyrene (BaP). Combined exposure enhanced hypoxia-induced gene expression but did not significantly alter BaP-induced gene expression. Protein carbonyl content was markedly elevated in fish subjected to combined exposure, indicating accumulation of reactive oxygen species (ROS). Application of diethyldithiocarbamate (DDC) to hypoxia-treated grouper liver explants similarly exaggerated hypoxia-induced gene expression as in the combined stress tissues in vivo. These observations suggest that ROS derived from the combined hypoxia and BaP stress have a role in enhancing hypoxia-induced gene expression.
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Affiliation(s)
- Richard Man Kit Yu
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, China
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17
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Khan S, Liu S, Stoner M, Safe S. Cobaltous chloride and hypoxia inhibit aryl hydrocarbon receptor-mediated responses in breast cancer cells. Toxicol Appl Pharmacol 2007; 223:28-38. [PMID: 17599377 PMCID: PMC1986799 DOI: 10.1016/j.taap.2007.05.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 05/08/2007] [Accepted: 05/17/2007] [Indexed: 10/23/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is expressed in estrogen receptor (ER)-positive ZR-75 breast cancer cells. Treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces CYP1A1 protein and mRNA levels and also activates inhibitory AhR-ERalpha crosstalk associated with hormone-induced reporter gene expression. In ZR-75 cells grown under hypoxia, induction of these AhR-mediated responses by TCDD was significantly inhibited. This was not accompanied by decreased nuclear AhR levels or decreased interaction of the AhR complex with the CYP1A1 gene promoter as determined in a chromatin immunoprecipitation assay. Hypoxia-induced loss of Ah-responsiveness was not associated with induction of hypoxia-inducible factor-1alpha or other factors that sequester the AhR nuclear translocation (Arnt) protein, and overexpression of Arnt under hypoxia did not restore Ah-responsiveness. The p65 subunit of NFkappaB which inhibits AhR-mediated transactivation was not induced by hypoxia and was primarily cytosolic in ZR-75 cells grown under hypoxic and normoxic conditions. In ZR-75 cells maintained under hypoxic conditions for 24 h, BRCA1 (an enhancer of AhR-mediated transactivation in breast cancer cells) was significantly decreased and this contributed to loss of Ah-responsiveness. In cells grown under hypoxia for 6 h, BRCA1 was not decreased, but induction of CYP1A1 by TCDD was significantly decreased. Cotreatment of ZR-75 cells with TCDD plus the protein synthesis inhibitor cycloheximide for 6 h enhanced CYP1A1 expression in cells grown under hypoxia and normoxia. These results suggest that hypoxia rapidly induces protein(s) that inhibit Ah-responsiveness and these may be similar to constitutively expressed inhibitors of Ah-responsiveness (under normoxia) that are also inhibited by cycloheximide.
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Affiliation(s)
- Shaheen Khan
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466
| | - Shengxi Liu
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX 77030-3303
| | - Matthew Stoner
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466
| | - Stephen Safe
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843-4466
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX 77030-3303
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18
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Schulte PM. Responses to environmental stressors in an estuarine fish: Interacting stressors and the impacts of local adaptation. J Therm Biol 2007. [DOI: 10.1016/j.jtherbio.2007.01.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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19
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Abstract
Nickel is a widely distributed metal that is industrially applied in many forms. Accumulated epidemiological evidence confirms that exposures to nickel compounds are associated with increased nasal and lung cancer incidence, both in mostly occupational exposures. Although the molecular mechanisms by which nickel compounds cause cancer are still under intense investigation, the carcinogenic actions of nickel compounds are thought to involve oxidative stress, genomic DNA damage, epigenetic effects, and the regulation of gene expression by activation of certain transcription factors related to corresponding signal transduction pathways. The present review summarizes our current knowledge on the molecular mechanisms of nickel carcinogenesis, with special emphasis on the role of nickel induced reactive oxygen species (ROS) and signal transduction pathways.
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Affiliation(s)
- Haitian Lu
- Nelson Institute of Environmental Medicine, School of Medicine, New York University, Tuxedo, New York 10987, USA
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20
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Allen JW, Johnson RS, Bhatia SN. Hypoxic inhibition of 3-methylcholanthrene-induced CYP1A1 expression is independent of HIF-1alpha. Toxicol Lett 2005; 155:151-9. [PMID: 15585370 DOI: 10.1016/j.toxlet.2004.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Revised: 09/08/2004] [Accepted: 09/08/2004] [Indexed: 11/29/2022]
Abstract
Hypoxia-inducible factor-1alpha (HIF-1alpha) and aryl hydrocarbon receptor (AhR) both require dimerization with AhR nuclear translocator (ARNT) to initiate transcription of their respective target genes. It has been proposed that competition for ARNT results in decreased targeting of AhR to cytochrome P450 1A1 (CYP1A1) under hypoxia. We established primary cultures of HIF-1alpha null hepatocytes to examine the interaction between HIF-1alpha and AhR signaling. Gene expression of known HIF targets phosphoglycerate kinase (PGK), vascular endothelial growth factor (VEGF) and glucose transporter-1 (GLUT-1) increased under hypoxia, but was reduced in the HIF null cultures. Concomitant treatment of cultures with hypoxia (1% O2) and 3-methylcholanthrene (an AhR ligand) did not significantly alter HIF target gene expression. Furthermore, enzymatic activity and transcription of CYP1A1 was inhibited by hypoxia in HIF-1alpha null cultures, indicating that HIF-1alpha is not directly involved in negative regulation of AhR signaling.
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Affiliation(s)
- Jared W Allen
- Division of Biological Sciences, Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
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21
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Kraemer LD, Schulte PM. Prior PCB exposure suppresses hypoxia-induced up-regulation of glycolytic enzymes in Fundulus heteroclitus. Comp Biochem Physiol C Toxicol Pharmacol 2004; 139:23-9. [PMID: 15556062 DOI: 10.1016/j.cca.2004.08.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Revised: 08/26/2004] [Accepted: 08/31/2004] [Indexed: 11/21/2022]
Abstract
Increased activity of the glycolytic enzymes is a conserved feature of the cellular response to hypoxia, and may represent a protective mechanism by which cells can survive short-term hypoxic exposure. Gene induction by hypoxia involves a dimer of the hypoxia inducible factor (HIF)-1 alpha and the nuclear cofactor HIF-1 beta, also called the aryl hydrocarbon receptor nuclear translocator (ARNT), which is also involved in induction of genes in response to aryl hydrocarbon exposure. To assess the possibility of interaction between these pathways, we examined changes in the activity of the glycolytic enzymes in response to hypoxia and polychlorinated biphenyl (PCB) exposure in the liver of a teleost fish, Fundulus heteroclitus. After 3 days of hypoxic exposure (dissolved oxygen levels between 1.5 and 2.0 mg/L), there were significant increases in the activity of six glycolytic enzymes (PGI, ALD, TPI, PGK, PGM and LDH). In contrast, intraperitoneal injection of 1 microg/g body weight of PCB #77 (3,3',4,4'-tetrachlorobiphenyl) caused significant decreases in glycolytic enzyme activity after 7 days of exposure. When fish were injected with PCB #77 and then (4 days later) exposed to hypoxia for 3 days as before, we observed no induction of the glycolytic enzymes. This suggests that there is an antagonistic interaction between exposure to PCBs and hypoxia in F. heteroclitus. Prior PCB exposure could make these fish less tolerant of environmental hypoxia.
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Affiliation(s)
- L D Kraemer
- INRS-ETE, Université du Québec, C.P. 7500, Sainte Foy, QC, Canada
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22
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Shang EHH, Wu RSS. Aquatic hypoxia is a teratogen and affects fish embryonic development. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2004; 38:4763-7. [PMID: 15487785 DOI: 10.1021/es0496423] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Hypoxia occurs over large areas in aquatic systems worldwide, and there is growing concern that hypoxia may affect aquatic animals, leading to population decline and changes in community by elimination of sensitive species. For the first time, we report that sublethal levels of hypoxia can significantly increase (+77.4%) malformation in fish embryonic development. Disruption of apoptotic pattern was clearly evident at 24 h post-fertilization, which may be a major cause of malformation. Furthermore, embryonic development was delayed, and balance of sex hormones (testosterone and estradiol) was disturbed during embryonic stages, implicating that subsequent sexual development may also be affected. Overall, our results imply that hypoxia may have a teratogenic effect on fish and delay fish embryonic development, which may subsequently impair species fitness leading to natural population decline.
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Affiliation(s)
- Eva H H Shang
- Centre for Coastal Pollution and Conservation and Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong SAR, People's Republic of China
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23
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Thum T, Borlak J. Mechanistic Role of Cytochrome P450 Monooxygenases in Oxidized Low-Density Lipoprotein–Induced Vascular Injury. Circ Res 2004; 94:e1-13. [PMID: 14656932 DOI: 10.1161/01.res.0000110081.03480.e9] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Oxidized low-density lipoprotein (oxLDL) is an important risk factor for vascular injury. Its role on coronary vasoconstriction remains speculative. Endothelial monooxygenases (cytochrome P450s [CYPs]) are regulators of vascular tonus through production of epoxy fatty acids. We investigated the effects of oxLDL on CYP monooxygenases in human arterial coronary endothelial cells and explanted healthy and atherosclerotic aortae. We found oxLDL to induce radical oxygen species production via the action of NADPH oxidase NOX4. Intracellular radical oxygen species production prompted reduced protein expression of the transcriptional regulator nuclear factor 1 (NF-1). We identified novel DNA binding sites for NF-1 in promoter regions of CYPs. DNA binding of NF-1 was confirmed by electromobility shift assays. OxLDL repressed DNA binding of NF-1 and diminished transcript level of CYP genes targeted by this factor. The production of endothelial-derived hyperpolarization factor, a key regulator of vascular tonus, was also reduced. Repression of CYP monooxygenases was reversed, and production of endothelial-derived hyperpolarization factor was normalized after treatment of endothelium with the lectin-like oxLDL receptor antagonist κ-carrageenan or blocking of LOX-1 with a specific antibody. This suggests a mechanistic role of CYP monooxygenases in oxLDL-induced vascular injury. Therapy of endothelial dysfunction through LOX-1 receptor antagonism will be an interesting avenue to explore. The full text of this article is available online at http://www.circresaha.org.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/metabolism
- Arteriosclerosis/genetics
- Arteriosclerosis/metabolism
- Blotting, Western
- Carrageenan/pharmacology
- Cells, Cultured
- Coronary Vessels/cytology
- Cytochrome P-450 Enzyme System/genetics
- Cytochrome P-450 Enzyme System/metabolism
- Cytochrome P-450 Enzyme System/physiology
- Electrophoretic Mobility Shift Assay
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/enzymology
- Endothelium, Vascular/metabolism
- Epoxide Hydrolases/genetics
- Epoxide Hydrolases/metabolism
- Humans
- Lipoproteins, LDL/pharmacology
- Malondialdehyde/analysis
- Nitric Oxide/biosynthesis
- Promoter Regions, Genetic
- Reactive Oxygen Species/metabolism
- Receptors, LDL/antagonists & inhibitors
- Receptors, Oxidized LDL
- Scavenger Receptors, Class E
- Transcription, Genetic
- Vascular Diseases/therapy
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Affiliation(s)
- Thomas Thum
- Center of Drug Research and Medical Biotechnology, Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany
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24
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Mastyugin V, Mezentsev A, Zhang WX, Ashkar S, Dunn MW, Laniado-Schwartzman M. Promoter activity and regulation of the corneal CYP4B1 gene by hypoxia. J Cell Biochem 2004; 91:1218-38. [PMID: 15048876 DOI: 10.1002/jcb.20018] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Hypoxic injury to the ocular surface provokes an inflammatory response that is mediated, in part, by corneal epithelial-derived 12-hydroxyeicosanoids. Recent studies indicate that a cytochrome P450 (CYP) monooxygenase, identified as CYP4B1, is involved in the production of these eicosanoids which exhibit potent inflammatory and angiogenic properties. We have isolated and cloned a corneal epithelial CYP4B1 full-length cDNA and demonstrated that the CYP4B1 mRNA is induced by hypoxia in vitro and in vivo. To further understand the molecular regulation that underlies the synthesis of these potent inflammatory eicosanoids in response to hypoxic injury, we isolated and cloned the CYP4B1 promoter region. GenomeWalker libraries constructed from rabbit corneal epithelial genomic DNA were used as templates for primary and nested PCR amplifications with gene- and adaptor-specific primers. A 3.41-kb DNA fragment of the 5'-flanking region of the CYP4B1 promoter was isolated, cloned, sequenced, and analyzed by computer software for the presence of known cis-acting elements. Analysis of the promoter sequence revealed the presence of consensus DNA binding sequences for factors known to activate gene transcription in response to hypoxia including HIF-1, NFkappaB, and AP-1. Transient transfection of luciferase reporter (pGL3-Basic) vectors containing different lengths of the CYP4B1 promoter fragment demonstrated hypoxia-induced transcription in rabbit corneal epithelial (RCE) cells. Electrophoretic mobility shift assay (EMSA) revealed a marked induction of nuclear binding activity for the labeled HIF-1 probe from the CYP4B1 promoter in nuclear extracts of cells exposed to hypoxia. This binding activity was due to sequence-specific binding to the HIF-1 oligonucleotide probe as shown by competition with excess unlabeled probe for the HIF-1 but not with unlabeled NFkappaB probe. The nuclear binding activity of AP-1 and NFkappaB probes from the CYP4B1 promoter was also enhanced in response to hypoxia suggesting that these transcription factors contribute to the hypoxic induction of CYP4B1 expression. The results of this study provide the first molecular mechanistic explanation for the induction of CYP4B1 and, thereby, the production of inflammatory eicosanoids in response to hypoxic injury. Further studies are needed to fully evaluate the molecular regulation of this gene during inflammation.
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Affiliation(s)
- Vladimir Mastyugin
- Department of Pharmacology, New York Medical College, Valhalla, New York 10595, USA
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25
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Davidson T, Salnikow K, Costa M. Hypoxia Inducible Factor-1α-Independent Suppression of Aryl Hydrocarbon Receptor-Regulated Genes by Nickel. Mol Pharmacol 2003; 64:1485-93. [PMID: 14645679 DOI: 10.1124/mol.64.6.1485] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Aryl hydrocarbon receptor (AhR)-dependent enzymes are involved in the biotransformation of harmful xenobiotics into more easily excretable metabolites. Cross-talk between the AhR pathway and the hypoxia inducible factor-1alpha (HIF-1alpha) pathway has been demonstrated previously, although the mechanism remains unclear and quite controversial. Because nickel is known to mimic hypoxia, we investigated the effects of short-term nickel exposure on AhR-dependent gene expression. Gene-chip analysis identified several AhR-dependent genes that are suppressed by exposure to nickel. Using Northern blots, we then confirmed that nickel can down-regulate both the basal and benzo[a]pyrene-inducible expression of AhR-dependent genes in mouse and human cell lines. Using a HIF-1alpha knockout cell line and 3-[2-[4-(bis-(4-fluorophenyl) methylene]-1-piperidinyl)ethyl]-2,3-dihydro-2-thioxo-4(1H)quinazolinone (R59949), which blocks HIF-1alpha protein accumulation, we show HIF-1alpha-independent suppression of AhR-dependent genes by nickel. Desferrioxamine and hypoxia were also able to suppress the basal and inducible expression levels of AhR-regulated genes. Finally, dimethyloxalylglycine, an inhibitor of Fe(II)- and 2-oxoglutarate-dependent dioxygenases also inhibited AhR-dependent expression in a HIF-1alpha-independent manner. Our data suggest that an Fe(II)-, oxoglutarate-, and oxygen-dependent enzyme may directly or indirectly be involved in the regulation of AhR-dependent transcriptional activity by nickel and other hypoxia-mimicking agents.
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Affiliation(s)
- Todd Davidson
- Nelson Institute of Environmental Medicine, New York University School of Medicine, NewYork, USA.
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26
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Choi JY, Oughton JA, Kerkvliet NI. Functional alterations in CD11b(+)Gr-1(+) cells in mice injected with allogeneic tumor cells and treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin. Int Immunopharmacol 2003; 3:553-70. [PMID: 12689660 DOI: 10.1016/s1567-5769(03)00046-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exposure results in an increased percentage of CD11b(+) (Mac-1(+)) cells in the spleens of mice challenged with P815 tumor cells, coincident with a failure of the mice to generate allospecific CD8(+) CTL activity. Since CD11b(+)Gr-1(+) myeloid suppressor cells (MSC) have been described as that which prevent cytotoxic T lymphocyte (CTL) development in a variety of disease states, we hypothesized that TCDD promoted MSC development, leading to suppression of CTL activity. The purpose of the present studies was to compare the phenotypic and functional characteristics of CD11b(+) cells in vehicle- and TCDD-treated mice during the P815 tumor allograft response to determine their potential to function as MSC. Initial studies showed that virtually all splenic CD11b(+) cells in both vehicle- and TCDD-treated mice co-expressed Gr-1. Consistent with MSC activity, CD11b(+)Gr-1(+) cells isolated from TCDD- but not vehicle-treated mice suppressed the development of CTL activity when added in vitro to mixed lymphocyte-P815 tumor cell cultures. Also consistent with MSC activity, this suppressive effect in vitro required cell-to-cell contact. Surprisingly, however, in vivo depletion of CD11b(+)Gr-1(+) cells failed to affect TCDD-induced suppression of the CTL response, arguing against an immunoregulatory role for the cells in vivo. Immunohistochemical analysis of the spleen showed that CD11b(+)Gr-1(+) cells were localized in the red pulp, and physically separated from the T cells in the white pulp. The localization of CD11b(+)Gr-1(+) cells in the red pulp was indicative of extramedullary myelopoiesis and suggested that TCDD enhanced myelopoiesis. A significantly enhanced neutrophilia in the blood of TCDD-treated mice supported this conclusion. CD11b(+)Gr-1(+) cells isolated from the blood or spleen of TCDD-treated mice produced up to fivefold higher levels of superoxide following PMA stimulation when compared with cells from vehicle-treated mice. However, unlike vehicle-treated mice, CD11b(+)Gr-1(+) cells from TCDD-treated mice were unable to kill YAC-1 target cells. These results indicate that TCDD exposure alters the host response to allogeneic tumor growth, resulting in enhanced myelopoiesis perhaps as a compensatory response to the suppressed T cell-mediated immunity in the face of an increasing P815 tumor burden. Furthermore, within the context of the P815 response, TCDD appears to alter the functional capabilities of mature neutrophils, by enhancing their oxidative burst capacity but reducing their tumoricidal response.
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Affiliation(s)
- Jin-Young Choi
- Department of Environmental and Molecular Toxicology, Agricultural Life Sciences Building, Room 1007 Oregon State University, Corvallis, OR 97331, USA
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27
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Wu RSS, Zhou BS, Randall DJ, Woo NYS, Lam PKS. Aquatic hypoxia is an disrupter and impairs fish reproduction. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2003; 37:1137-1141. [PMID: 12680666 DOI: 10.1021/es0258327] [Citation(s) in RCA: 188] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
There is increasing concern that certain chemicals in the aquatic environment can disrupt endocrine systems, leading to reproductive impairment and threatening survival of wild populations of invertebrates, fish, bird, reptiles, and wildlife. For the first time, we report that hypoxia is also an endocrine disruptor and poses a significant threat to the reproduction and hence sustainability of fish populations. Serum levels of testosterone, estradiol, and triiodothyronine significantly decreased in carp (Cyprinus carpio) upon chronic exposure to hypoxia. These hormonal changes were associated with retarded gonadal development in both male and female carp, reduced spawning success, sperm motility, fertilization success, hatching rate, and larval survival, indicating that adverse effects of hypoxia on reproductive performance resulted from endocrine disruption. Since aquatic hypoxia commonly occurs over thousands of square kilometers in aquatic systems worldwide, our results imply that endocrine disruption and reproductive impairment in fish may be a widespread environmental problem.
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Affiliation(s)
- Rudolf S S Wu
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong.
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Zhong H, Hanrahan C, van der Poel H, Simons JW. Hypoxia-inducible factor 1alpha and 1beta proteins share common signaling pathways in human prostate cancer cells. Biochem Biophys Res Commun 2001; 284:352-6. [PMID: 11394885 DOI: 10.1006/bbrc.2001.4981] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Hypoxia-inducible factor 1 (HIF-1) is a heterodimeric transcription factor consisting alpha and beta subunits. It is critically involved in cancer cell hypoxia adaptation, glycolysis, and angiogenesis. HIF-1beta is associated with HIF-1 functions as a dimerization partner of HIF-1alpha, and is on the other hand associated with carcinogenesis via dioxin signaling. Regulation of HIF-1beta protein expression was investigated in human prostate cancer (PCA) cells. HIF-1beta protein was expressed constitutively under nonhypoxic conditions in all human PCA cells tested, and was up-regulated by hypoxia, CoCl2, EGF, serum, or PMA in moderate levels. Compared to that of HIF-1alpha, the constitutive, serum-, EGF-, and PMA-increased HIF-1beta protein expression were also inhibited by selective PI3K or FRAP/TOR inhibitors but in higher doses. Hypoxia partially reversed the dose dependent inhibition of HIF-1beta. These results suggest that HIF-1alpha and beta share common signaling pathways for nuclear protein accumulation.
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Affiliation(s)
- H Zhong
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
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