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Hao W, Hu X, Zhu F, Chang J, Li J, Li W, Wang H, Guo B, Li J, Xu P, Zhang Y. Enantioselective Distribution, Degradation, and Metabolite Formation of Myclobutanil and Transcriptional Responses of Metabolic-Related Genes in Rats. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:8830-8837. [PMID: 29957933 DOI: 10.1021/acs.est.8b01721] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Myclobutanil (MT), a chiral fungicide, can be metabolized enantioselectively in organisms. In this work, the associated absorption, distribution, metabolism and transcriptional responses of MT in rats were determined following a single-dose (10 mg·kg-1 body weight) exposure to rac-, (+)- or (-)-MT. The enantiomer fractions (EFs) were less than 0.5 with time in the liver, kidney, heart, lung, and testis, suggesting preferential enrichment of (-)-MT in these tissues. Furthermore, there was conversion of (+)-form to (-)-form in the liver and kidney after 6 h exposure to enantiopure (+)-MT. Enrichment and degradation of the two enantiomers differed between rac-MT and MT-enantiomers groups, suggesting that MT bioaccumulation is enantiomer-specific. Interestingly, the degradation half-life of MT in the liver with rac-MT treatment was shorter than that with both MT-enantiomer treatments. One reason may be that the gene expression levels of cytochrome P450 1a2 ( cyp1a2) and cyp3a2 genes in livers treated with rac-MT were the highest among the three exposure groups. In addition, a positive correlation between the expression of cyp2e1 and cyp3a2 genes and rac-MT concentration was found in livers exposed to rac-MT. Simultaneously, five chiral metabolites were detected, and the enantiomers of three metabolites, RH-9090, RH-9089, and M2, were separated. The detected enantiomers of (+)-MT metabolites were in complete contrast with those of (-)-MT metabolites. According to the results, a metabolic pathway of MT in male rats was proposed, which included the following five metabolites: RH-9089, RH-9090, RH-9090 Sulfate, M1, and M2. The possible metabolic enzymes were marked in the pathway. The findings of this study provide more specific insights into the enantioselective metabolic mechanism of chiral triazole fungicides.
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Affiliation(s)
- Weiyu Hao
- Research Center for Eco-Environmental Science , Chinese Academy of Sciences , Shuangqing RD 18 , Beijing 100085 , China
- University of the Chinese Academy of Sciences , Yuquan RD 19 a , Beijing 100049 , China
| | - Xiao Hu
- Research Center for Eco-Environmental Science , Chinese Academy of Sciences , Shuangqing RD 18 , Beijing 100085 , China
- University of the Chinese Academy of Sciences , Yuquan RD 19 a , Beijing 100049 , China
| | - Feilong Zhu
- Research Center for Eco-Environmental Science , Chinese Academy of Sciences , Shuangqing RD 18 , Beijing 100085 , China
- University of the Chinese Academy of Sciences , Yuquan RD 19 a , Beijing 100049 , China
| | - Jing Chang
- Research Center for Eco-Environmental Science , Chinese Academy of Sciences , Shuangqing RD 18 , Beijing 100085 , China
- University of the Chinese Academy of Sciences , Yuquan RD 19 a , Beijing 100049 , China
| | - Jitong Li
- Research Center for Eco-Environmental Science , Chinese Academy of Sciences , Shuangqing RD 18 , Beijing 100085 , China
| | - Wei Li
- Research Center for Eco-Environmental Science , Chinese Academy of Sciences , Shuangqing RD 18 , Beijing 100085 , China
| | - Huili Wang
- Research Center for Eco-Environmental Science , Chinese Academy of Sciences , Shuangqing RD 18 , Beijing 100085 , China
| | - Baoyuan Guo
- Research Center for Eco-Environmental Science , Chinese Academy of Sciences , Shuangqing RD 18 , Beijing 100085 , China
| | - Jianzhong Li
- Research Center for Eco-Environmental Science , Chinese Academy of Sciences , Shuangqing RD 18 , Beijing 100085 , China
| | - Peng Xu
- Research Center for Eco-Environmental Science , Chinese Academy of Sciences , Shuangqing RD 18 , Beijing 100085 , China
| | - Yanfeng Zhang
- Research Center for Eco-Environmental Science , Chinese Academy of Sciences , Shuangqing RD 18 , Beijing 100085 , China
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Regulation of Liver Enriched Transcription Factors in Rat Hepatocytes Cultures on Collagen and EHS Sarcoma Matrices. PLoS One 2015; 10:e0124867. [PMID: 25901575 PMCID: PMC4406752 DOI: 10.1371/journal.pone.0124867] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 03/13/2015] [Indexed: 02/07/2023] Open
Abstract
Liver-enriched transcription factors (LETF) play a crucial role in the control of liver-specific gene expression and for hepatocytes to retain their molecular and cellular functions complex interactions with extra cellular matrix (ECM) are required However, during cell isolation ECM interactions are disrupted and for hepatocytes to regain metabolic competency cells are cultured on ECM substrata. The regulation of LETFs in hepatocytes cultured on different ECM has not been studied in detail. We therefore compared two common sources of ECM and evaluated cellular morphology and hepatocyte differentiation by investigating DNA binding activity of LETFs at gene specific promoters and marker genes of hepatic metabolism. Furthermore, we studied testosterone metabolism and albumin synthesis to assess the metabolic competence of cell cultures. Despite significant difference in morphological appearance and except for HNF1β (p<0.001) most LETFs and several of their target genes did not differ in transcript expression after Bonferroni adjustment when cultured on collagen or Matrigel. Nonetheless, Western blotting revealed HNF1β, HNF3α, HNF3γ, HNF4α, HNF6 and the smaller subunits of C/EBPα and C/EBPβ to be more abundant on Matrigel cultured cells. Likewise, DNA binding activity of HNF3α, HNF3β, HNF4α, HNF6 and gene expression of hepatic lineage markers were increased on Matrigel cultured hepatocytes. To further investigate hepatic gene regulation, the effects of Aroclor 1254 treatment, e.g. a potent inducer of xenobiotic defense were studied in vivo and in vitro. The gene expression of C/EBP-α increased in rat liver and hepatocytes cultured on collagen and this treatment induced DNA binding activity of HNF4α, C/EBPα and C/EBPβ and gene expression of CYP1A1 and CYP1A2 in vivo and in vitro. Taken collectively, two sources of ECM greatly affected hepatocyte morphology, activity of liver enriched transcription factors, hepatic gene expression and metabolic competency that should be considered when used in cell biology studies and drug toxicity testing.
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Robles-Escajeda E, Martínez A, Varela-Ramirez A, Sánchez-Delgado RA, Aguilera RJ. Analysis of the cytotoxic effects of ruthenium-ketoconazole and ruthenium-clotrimazole complexes on cancer cells. Cell Biol Toxicol 2013; 29:431-43. [PMID: 24272524 PMCID: PMC4207122 DOI: 10.1007/s10565-013-9264-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 11/12/2013] [Indexed: 12/26/2022]
Abstract
Ruthenium-based compounds have intriguing anti-cancer properties, and some of these novel compounds are currently in clinical trials. To continue the development of new metal-based drug combinations, we coupled ruthenium (Ru) with the azole compounds ketoconazole (KTZ) and clotrimazole (CTZ), which are well-known antifungal agents that also display anticancer properties. We report the activity of a series of 12 Ru-KTZ and Ru-CTZ compounds against three prostate tumor cell lines with different androgen sensitivity, as well as cervical cancer and lymphoblastic lymphoma cell lines. In addition, human cell lines were used to evaluate the toxicity against non-transformed cells and to establish selectivity indexes. Our results indicate that the combination of ruthenium and KTZ/CTZ in a single molecule results in complexes that are more cytotoxic than the individual components alone, displaying in some cases low micromolar CC50 values and high selectivity indexes. Additionally, all compounds are more cytotoxic against prostate cell lines with lower cytotoxicity against non-transformed epidermal cell lines. Some of the compounds were found to primarily induce cell death via apoptosis yet weakly interact with DNA. Our studies also demonstrate that the cytotoxicity induced by our Ru-based compounds is not directly related to their ability to interact with DNA.
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Affiliation(s)
- Elisa Robles-Escajeda
- Border Biomedical Research Center and Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, 79968, USA
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Lal K, Mani U, Pandey R, Singh N, Singh AK, Patel DK, Singh MP, Murthy RC. Multiple approaches to evaluate the toxicity of the biomass fuel cow dung (kanda) smoke. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2011; 74:2126-2132. [PMID: 21719104 DOI: 10.1016/j.ecoenv.2011.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 05/23/2011] [Accepted: 06/05/2011] [Indexed: 05/31/2023]
Abstract
Cow dung (Kanda) is a major source of energy in rural and urban population of developing countries and is burnt in traditional open stoves in confined space of kitchen without proper ventilation. In epidemiological studies, biomass fuel smoke has been reported to be responsible for several respiratory disorders in exposed population. In a laboratory experiment, female wistar rats were exposed to kanda smoke for 60 min/day over a period of 12 weeks. Chemical analysis of smoke showed the presence of PAHs. The increase in CYP1A1, GST-ya, GST-yc expression was found in 12 week exposed lung tissues as compared with controls. The exposure to smoke resulted in significant alteration in the BALF cells in the form of clustering of alveolar macrophages and giant cell formation with vacuolated cytoplasm. The macrophages also showed thickness and villi like projections on the cell surface thus reducing their phagocytic activities. Histopathological changes in lung tissue were manifested in the form of damage to bronchiolar epithelium, edema and thickening of alveolar septa and emphysema after 4 and 8 week of exposure. These findings suggest that exposure to kanda smoke increases pulmonary tissue damage and may result in various forms of respiratory infections in the exposed popultion.
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Affiliation(s)
- Kewal Lal
- Inhalation Toxicology Division, Indian Institute of Toxicology Research, Mahatma Gandhi Marg, PO Box No. 80, Lucknow 226001, UP, India
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Weltmeier F, Borlak J. A high resolution genome-wide scan of HNF4α recognition sites infers a regulatory gene network in colon cancer. PLoS One 2011; 6:e21667. [PMID: 21829439 PMCID: PMC3145629 DOI: 10.1371/journal.pone.0021667] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 06/06/2011] [Indexed: 11/18/2022] Open
Abstract
The hepatic nuclear factor HNF4α is a versatile transcription factor and controls expression of many genes in development, metabolism and disease. To delineate its regulatory gene network in colon cancer and to define novel gene targets a comprehensive genome-wide scan was carried out at a resolution of 35 bp with chromatin IP DNA obtained from the human colon carcinoma cell line Caco-2 that is a particularly rich source of HNF4α. More than 90% of HNF4α binding sites were mapped as promoter distal sequences while enhancer elements could be defined to foster chromatin loops for interaction with other promoter-bound transcription factors. Sequence motif analysis by various genetic algorithms evidenced a unique enhanceosome that consisted of the nuclear proteins ERα, AP1, GATA and HNF1α as cooperating transcription factors. Overall >17,500 DNA binding sites were identified with a gene/binding site ratio that differed >6-fold between chromosomes and clustered in distinct chromosomal regions amongst >6600 genes targeted by HNF4α. Evidence is presented for nuclear receptor cross-talk of HNF4α and estrogen receptor α that is recapitulated at the sequence level. Remarkably, the Y-chromosome is devoid of HNF4α binding sites. The functional importance of enrichment sites was confirmed in genome-wide gene expression studies at varying HNF4α protein levels. Taken collectively, a genome-wide scan of HNF4α binding sites is reported to better understand basic mechanisms of transcriptional control of HNF4α targeted genes. Novel promoter distal binding sites are identified which form an enhanceosome thereby facilitating RNA processing events.
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Affiliation(s)
- Fridtjof Weltmeier
- Department of Molecular Medicine and Medical Biotechnology, Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany
| | - Juergen Borlak
- Department of Molecular Medicine and Medical Biotechnology, Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany
- Centre for Pharmacology and Toxicology, Hannover Medical School, Hannover, Germany
- * E-mail:
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Transactivation of genes encoding for phase II enzymes and phase III transporters by phytochemical antioxidants. Molecules 2010; 15:6332-48. [PMID: 20877225 PMCID: PMC6257698 DOI: 10.3390/molecules15096332] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 08/31/2010] [Accepted: 09/03/2010] [Indexed: 01/27/2023] Open
Abstract
The induction of phase II enzymes and phase III transporters contributes to the metabolism, detoxification of xenobiotics, antioxidant capacity, redox homeostasis and cell viability. Transactivation of the genes that encode for phase II enzymes and phase III transporters is coordinatively regulated by activating transcription factors in response to external stimuli. Comprehensive studies indicate that antioxidant phytochemicals promote the induction of phase II enzymes and/or phase III transporters through various signaling pathways, including phosphoinositide 3-kinase, protein kinase C, and mitogen-activated protein kinases. This paper focuses on the molecular mechanisms and signaling pathways responsible for the transactivation of genes encoding for these proteins, as orchestrated by a series of transcription factors and related signaling components.
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Jones HS, Panter GH, Hutchinson TH, Chipman JK. Oxidative and Conjugative Xenobiotic Metabolism in Zebrafish Larvae In Vivo. Zebrafish 2010; 7:23-30. [DOI: 10.1089/zeb.2009.0630] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Huw S. Jones
- The School of Biosciences, The University of Birmingham, Birmingham, West Midlands, United Kingdom
| | - Grace H. Panter
- Brixham Environmental Laboratory, AstraZeneca, Brixham, Devon, United Kingdom
| | - Thomas H. Hutchinson
- Centre for Environmental, Fisheries, and Aquaculture Science, Weymouth, Dorset, United Kingdom
| | - J. Kevin Chipman
- The School of Biosciences, The University of Birmingham, Birmingham, West Midlands, United Kingdom
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Han X, O'Connor JC, Donner EM, Nabb DL, Mingoia RT, Snajdr SI, Clarke JJ, Kaplan AM. Non-coplanar 2,2',3,3',4,4',5,5',6,6'-decachlorobiphenyl (PCB 209) did not induce cytochrome P450 enzyme activities in primary cultured rat hepatocytes, was not genotoxic, and did not exhibit endocrine-modulating activities. Toxicology 2008; 255:177-86. [PMID: 19022331 DOI: 10.1016/j.tox.2008.10.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 10/21/2008] [Accepted: 10/22/2008] [Indexed: 11/25/2022]
Abstract
2,2',3,3',4,4',5,5',6,6'-Decachlorobiphenyl (PCB 209) is a fully chlorinated, non-coplanar biphenyl. To demonstrate that PCB 209 is not likely to exhibit human health hazards common to coplanar PCBs it was tested for cytochrome P450 (P450) enzyme induction potentials, genetic toxicity, and endocrine-modulating activity. PCB 209 (dose from 0.005 to 5000 ng/mL) did not significantly induce P450 CYP1A, 2A, 2B, 3A, or 4A enzyme activities in primary cultured rat hepatocytes. In contrast, Aroclor 1260, a PCB mixture that contains approximately 60% chlorine by weight, showed significant induction of P450 CYP1A, 2A, 2B, and 3A within the same dose range. PCB 209 (dose from 100 to 5000 microg/plate) was negative in the bacterial mutagenicity (Ames) test in Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537 or in Eschericia coli strain WP2uvrA. PCB 209 (dose from 25 to 150 microg/mL) was also negative for forward mutations at the thymidine kinase (TK+/-) locus of L5178Y mouse lymphoma cells. The Ames and the mouse lymphoma assays were both conducted in the absence and presence of rat liver S9 fraction. PCB 209 (dose from 500 to 2000 mg/kg by single dose oral gavage) did not induce an increase in the frequency of micronuclei in polychromatic erythrocytes in mouse bone marrow in vivo. PCB 209 did not induce estrogenic effects when administered by gavage to ovariectomized adult female rats at 500 and 1000 mg/kg for 4 days, nor did it produce alterations consistent with endocrine-modulating activity in adult intact male rats when administered by gavage at 500 and 1000 mg/kg for 15 consecutive days.
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Affiliation(s)
- Xing Han
- DuPont Haskell Global Centers for Health & Environmental Sciences, Newark, DE 19714, USA.
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Vickers A. Toxicogenomics in Non-Clinical Safety Studies. Genomics 2008. [DOI: 10.3109/9781420067064-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Borlak J, Zwadlo C. Expression of drug-metabolizing enzymes, nuclear transcription factors and ABC transporters in Caco-2 cells. Xenobiotica 2008; 33:927-43. [PMID: 14514442 DOI: 10.1080/00498250310001614286] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
1. Caco-2 cells are frequently used in intestinal drug absorption and metabolism studies, but little is known about the effects of drugs on the simultaneous expression of genes coding for drug-metabolizing enzymes (DMEs), nuclear transcription factors and ABC transporters. 2. The gene expression and enzyme activities of control and Aroclor 1254-treated cultures were therefore explored, the latter being a powerful inducer of DMEs. Fourteen- and 80-fold induction of CYP1A1 and CYP1A2 mRNA were shown, whereas expression of other DMEs was either increased (CYP2C8-2C19, 10-fold; CYP3A5, twofold; FMO1, 2 and 5, twofold; epoxide hydrolase, threefold) or repressed (CYP2D6 and CYP2E1 to 75% of control values). 3. Notably, gene copies of CYP3A4 and CYP2B6/7 were below the limit of detection, but a three- and 10-fold induction of HNF 1alpha + beta, HNF-4alpha4 and a similar 10-fold increase in STAT 3 and 4 was observed. 4. Similarly, c/EBP transcripts were only detected in treated cell cultures, but MRP1, its isoforms 3-5 as well as MDR-1 were increased threefold after dosing with Aroclor 1254. 5. Overall, CYP gene expression correlated well with the cognate enzyme activity using testosterone as a marker substrate.
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Affiliation(s)
- J Borlak
- Fraunhofer Institute of Toxicology and Experimental Medicine, Center for Drug Research and Medical Biotechnology, Nicolai-Fuchs-Str. 1 D-30659, Hannover, Germany.
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Borlak J, Jenke HS. Cross-talk between Aryl Hydrocarbon Receptor and Mitogen-Activated Protein Kinase Signaling Pathway in Liver Cancer through c-raf Transcriptional Regulation. Mol Cancer Res 2008; 6:1326-36. [DOI: 10.1158/1541-7786.mcr-08-0042] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Niehof M, Borlak J. HNF4 alpha and the Ca-channel TRPC1 are novel disease candidate genes in diabetic nephropathy. Diabetes 2008; 57:1069-77. [PMID: 18184923 DOI: 10.2337/db07-1065] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The nuclear receptor hepatic nuclear factor 4 alpha (HNF 4 alpha) is a master regulatory protein and an essential player in the control of a wide range of metabolic processes. Dysfunction of HNF 4 alpha is associated with metabolic disorders including diabetes. We were particularly interested in investigating molecular causes associated with diabetic nephropathy. RESEARCH DESIGN AND METHODS Novel disease candidate genes were identified by the chromatin immunoprecipitation-cloning assay and by sequencing of immunoprecipitated DNA. Expression of candidate genes was analyzed in kidney and liver of Zucker diabetic fatty (ZDF) and of streptozotocin (STZ)-administered rats and after siRNA-mediated silencing of HNF 4 alpha. RESULTS We identified the calcium-permeable nonselective transient receptor potential cation channel, subfamily C, member 1 (TRPC1) as a novel HNF 4 alpha gene target. Strikingly, TRPC1 is localized on human chromosome 3q22-24, i.e., a region considered to be a hotspot for diabetic nephropathy. We observed a significant reduction of TRPC1 gene expression in kidney and liver of diabetic ZDF and of STZ-administered rats as a result of HNF 4 alpha dysfunction. We found HNF 4 alpha and TRPC1 protein expression to be repressed in kidneys of diabetic patients diagnosed with nodular glomerulosceloris as evidenced by immunohistochemistry. Finally, siRNA-mediated functional knock down of HNF 4 alpha repressed TRPC1 gene expression in cell culture experiments. CONCLUSIONS Taken collectively, results obtained from animal studies could be translated to human diabetic nephropathy; there is evidence for a common regulation of HNF 4 alpha and TRPC1 in human and rat kidney pathologies. We propose dysregulation of HNF 4 alpha and TRPC1 as a possible molecular rationale in diabetic nephropathy.
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Affiliation(s)
- Monika Niehof
- Fraunhofer Institute of Toxicology and Experimental Medicine, Center of Molecular Medicine and Medical Biotechnology, Nikolai-Fuchs-Str. 1, 30625 Hannover, Germany
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Thum T, Borlak J. Detection of early signals of hepatotoxicity by gene expression profiling studies with cultures of metabolically competent human hepatocytes. Arch Toxicol 2007; 82:89-101. [PMID: 17851650 DOI: 10.1007/s00204-007-0234-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Accepted: 07/27/2007] [Indexed: 10/22/2022]
Abstract
Xenobiotic induced liver injury is a leading cause for drug withdrawal and toxicogenomics may help to identify molecular causes. Here we report studies with cultures of human hepatocytes to detect early responses of liver toxicity upon treatment with the hepatotoxin Aroclor 1254. We studied transcript abundance of 302 genes with biological functions in detoxification, cell proliferation, tumor development, stress response, signal transduction, apoptosis and cell cycle regulation. More than 40 genes were regulated by at least twofold change, the majority coding for xenobiotic defense. In the case of CYP monooxygenases induction of coded protein was confirmed by Western immunoblotting whereas catalytic activities were determined by assaying for testosterone hydroxylase activity. There was good agreement between gene and protein expression and enzyme activity of CYP monooxygenases. In conclusion, xenobiotic induced hepatotoxicity may arise via several mechanisms and gene expression profiling helps to pinpoint location and pathways perturbed by drugs and chemicals.
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Affiliation(s)
- Thomas Thum
- Fraunhofer Institute of Toxicology and Experimental Medicine, Centre for Drug Research and Medical Biotechnology, Nikolai-Fuchs-Str.1, 30625, Hannover, Germany
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Rahman MM, Elmi S, Chang TKH, Bai N, Sallam NA, Lemos VS, Moien-Afshari F, Laher I. Increased vascular contractility in isolated vessels from cigarette smoking rats is mediated by basal endothelin release. Vascul Pharmacol 2007; 46:35-42. [PMID: 16901763 DOI: 10.1016/j.vph.2006.06.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2005] [Revised: 05/23/2006] [Accepted: 06/13/2006] [Indexed: 10/24/2022]
Abstract
The effect of chronic cigarette smoking on endothelin modulation of vascular contraction, and CYP enzyme levels was studied in 20 male Sprague-Dawley rats. The animals were divided equally into smoking and non-smoking groups. The smoking group was exposed to 6 research cigarettes per rat per day 5 days a week for 16 weeks. The control group was sham smoked. Functional contractile studies were performed in aortas and carotid arteries to determine the regulation of vascular tone by basal release of endothelin. Liver samples were analyzed for CYP1A1 and CYP1A2 gene expression by RT-PCR. Plasma samples were assessed for endothelin-1 (ET-1) level by enzyme immuno assay (EIA). Treatment of aortas and carotid arteries with bosentan, the dual endothelin receptor antagonist, caused a significant reduction in constrictor responses of smoking rats, indicating, increase greater regulation of tone by endothelin in smoker rats compared to controls. There was a greater expression of the cytochrome P450-liver enzymes (CYP1A1 and CYP1A2) in smoker rats. Body weight gain was also significantly decreased in smoker rats. We conclude that increased endothelin release in smoker rats significantly contributes to increased arterial tone and so contribute to the cardiovascular pathophysiology associated with cigarette smoking, such as increased vascular muscularization, increased contraction, decreased dilation and possibly vasospasm.
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Affiliation(s)
- Mohammad M Rahman
- Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, 2176 Health Sciences Mall, University of British Columbia, Vancouver, BC, Canada
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Thum T, Erpenbeck VJ, Moeller J, Hohlfeld JM, Krug N, Borlak J. Expression of xenobiotic metabolizing enzymes in different lung compartments of smokers and nonsmokers. ENVIRONMENTAL HEALTH PERSPECTIVES 2006; 114:1655-61. [PMID: 17107849 PMCID: PMC1665420 DOI: 10.1289/ehp.8861] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Accepted: 07/19/2006] [Indexed: 05/12/2023]
Abstract
BACKGROUND Cytochrome P450 monooxygenases (CYP) play an important role in the defense against inhaled toxicants, and expression of CYP enzymes may differ among various lung cells and tissue compartments. METHODS We studied the effects of tobacco smoke in volunteers and investigated gene expression of 19 CYPs and 3 flavin-containing monooxygenases, as well as isoforms of glutathione S-transferases (GST) and uridine diphosphate glucuronosyltransferases (UGT) and the microsomal epoxide hydrolase (EPHX1) in bronchoalveolar lavage cells and bronchial biopsies derived from smokers (n = 8) and nonsmokers (n = 10). We also investigated gene expression of nuclear transcription factors known to be involved in the regulation of xenobiotic metabolism enzymes. RESULTS Gene expression of CYP1A1, CYP1B1, CYP2S1, GSTP1, and EPHX1 was induced in bronchoalveolar lavage cells of smokers, whereas expression of CYP2B6/7, CYP3A5, and UGT2A1 was repressed. In bronchial biopsies of smokers, CYP1A1, CYP1B1, CYP2C9, GSTP1, and GSTA2 were induced, but CYP2J2 and EPHX1 were repressed. Induction of CYP1A1 and CYP1B1 transcript abundance resulted in increased activity of the coded enzyme. Finally, expression of the liver X receptor and the glucocorticoid receptor was significantly up-regulated in bronchoalveolar lavage cells of smokers. CONCLUSIONS We found gene expression of pulmonary xenobiotic metabolizing enzymes and certain key transcription factors to be regulated in bronchoalveolar lavage cells and bronchial biopsies of smokers. The observed changes demonstrate tissue specificity in xenobiotic metabolism, with likely implications for the metabolic activation of procarcinogens to ultimate carcinogens of tobacco smoke.
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Affiliation(s)
- Thomas Thum
- Drug Research and Medical Biotechnology, Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany
- Bayerische Julius-Maximilians Universität, Medizinische Klinik I, Würzburg, Germany
| | - Veit J. Erpenbeck
- Immunology/Allergology and Clinical Inhalation, Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany
| | - Julia Moeller
- Drug Research and Medical Biotechnology, Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany
- Immunology/Allergology and Clinical Inhalation, Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany
| | - Jens M. Hohlfeld
- Immunology/Allergology and Clinical Inhalation, Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany
| | - Norbert Krug
- Immunology/Allergology and Clinical Inhalation, Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany
| | - Jürgen Borlak
- Drug Research and Medical Biotechnology, Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany
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Fukuda J, Sakai Y, Nakazawa K. Novel hepatocyte culture system developed using microfabrication and collagen/polyethylene glycol microcontact printing. Biomaterials 2005; 27:1061-70. [PMID: 16111746 DOI: 10.1016/j.biomaterials.2005.07.031] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2005] [Accepted: 07/21/2005] [Indexed: 11/30/2022]
Abstract
The better understanding of cell biology and cell communication requires novel culture systems that better represent the natural cell environment in tissues and organs. We developed a spherical organoid (spheroid) microarray culture system using a combination of microfabrication and microcontact printing. The system consisted of a chip that had cylindrical cavities of 300 microm diameter at a density of 700 cavities/cm2. The bottom faces of these cavities were defined as two different regions that either supported or inhibited cell adhesion. In the cell adhesion region, the center of the bottom face of a 100 microm diameter in a cavity was modified with collagen (Col), and in the non-adhesion region, the entire region around the cavity, except the Col spots, was modified with polyethylene glycol. Primary hepatocytes spontaneously formed spheroids with a uniform diameter at the center of each cavity on the chip. Hepatocytes forming spheroids had a cuboidal cell shape, similar to hepatocytes in vivo, and stably maintained liver-specific phenotypes, such as liver-enriched transcriptional factors, albumin secretion, urea cycle enzymes, and intercellular adhesion molecules. This novel culture system may be applicable as a cellular platform for fundamental studies in cell biology and tissue engineering applications.
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Affiliation(s)
- Junji Fukuda
- Department of Chemical Processes and Environments, The University of Kitakyushu, 1-1 Hibikino, Wakamatsu-ku, Kitakyushu 808-0135, Japan
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17
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Borlak J, Blickwede M, Hansen T, Koch W, Walles M, Levsen K. Metabolism of verapamil in cultures of rat alveolar epithelial cells and pharmacokinetics after administration by intravenous and inhalation routes. Drug Metab Dispos 2005; 33:1108-14. [PMID: 15886350 DOI: 10.1124/dmd.105.003723] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Administration of therapeutic entities by inhalation opens new possibilities for drug entry into systemic circulation, but this requires passage through the alveolar epithelium. Little is known about the pulmonary metabolism of verapamil. Specifically, this cardiovascular drug suffers from extensive first pass metabolism. We therefore evaluated the metabolism of verapamil in cultured alveolar epithelium and compared findings with results after administration by inhalation and intravenous routes. Specifically, cell culture of alveolar epithelium was characterized by gene expression of surfactant proteins A, B, C, and D, by immunohistochemistry of surfactant protein C, by staining for laminar bodies, and by gene expression of cytochrome P450 monooxygenases. During 6 days of culture expression, all cellular differentiation markers were obvious, albeit at different levels. With testosterone as substrate, we found alveolar epithelial cells to produce several stereo- and site-specific hydroxylation products. This provided evidence for metabolic competence of cultured alveolar epithelial cells. With verapamil as substrate, only limited production of metabolites was observed in cell culture assays, and similar results were recorded after administration by inhalation and intravenous routes. Likewise, elimination of verapamil from lung tissue and plasma was similar by both routes of administration. In conclusion, administration of verapamil by inhalation-abrogated extensive first pass metabolism frequently seen after oral application, and this may well be extended to the development of drugs with similar pharmacokinetic defects.
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Affiliation(s)
- Jürgen Borlak
- Department of Drug Research and Medical Biotechnology, Fraunhofer Institute of Toxicology and Experimental Medicine, Nikolai-Fuchs-Str. 1, D-30625 Hannover, Germany.
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18
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Borlak J, Schulte I, Thum T. Androgen metabolism in thymus of fetal and adult rats. Drug Metab Dispos 2005; 32:675-9. [PMID: 15155560 DOI: 10.1124/dmd.32.6.675] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cytochrome P450 (P450) monooxygenases play a role in target tissue metabolic activation of xenobiotics and/or endogenous compounds, such as vasoactive molecules or hormones. Indeed, tissue-specific metabolism of steroids is important in a variety of organs, including thymus, and may alter tissue-specific functions. Steroids have been shown to regulate thymus growth and function, but surprisingly little is known about expression of the responsible enzyme systems in thymus tissue, nor is the thymus-specific biotransformation of testosterone known. We therefore investigated gene and protein expression, total protein content, and enzyme activity of major P450 isoforms and other key steroid-metabolizing enzymes in thymus tissue of adult and fetal rats. We detected 6 beta-hydroxytestosterone (HT), 7 alpha-HT, 16 alpha-HT, 2 alpha-HT, and androstenedione to be major testosterone metabolites in the adult thymus. The high production of 7 alpha-HT and 16 alpha-HT correlated well with the gene and protein expression of CYP2A1/2 and CYP2B1/2 in thymus of adult animals. When compared with fetal thymic tissue, CYP2A1/2, 17beta-hydroxysteroid dehydrogenase isoform 1 (17 beta-HSDH1) and the androgen receptor were 8-, 3-, and 3-fold more highly expressed in adult rats, whereas 17 beta-HSDH2, 17 beta-HSDH3, and 5 alpha-reductase were reduced to 12%, 0%, and 32% of those in fetal thymus. In conclusion, we demonstrated that rat thymus expresses a variety of cytochrome P450 monooxygenases and other steroid-metabolizing enzymes, and it successfully metabolizes testosterone. Changes of the underlying steroid-metabolizing enzyme systems may aid in understanding the role of androgens in altering biological functions of the thymus.
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Affiliation(s)
- Jürgen Borlak
- Fraunhofer Institute of Toxicology and Experimental Medicine, Center for Drug Research and Medical Biotechnology, Nikolai-Fuchs-Str. 1, D-30625 Hannover, Germany.
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19
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Niehof M, Borlak J. RSK4 and PAK5 Are Novel Candidate Genes in Diabetic Rat Kidney and Brain. Mol Pharmacol 2004; 67:604-11. [PMID: 15615695 DOI: 10.1124/mol.104.008672] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The orphan hepatic nuclear factor (HNF) HNF4alpha is of pivotal importance for liver development and hepatocellular differentiation and plays an essential role in a regulatory circuitry to control a wide range of metabolic processes. It also targets genes in other organs, including pancreas, kidney, intestine, and colon; promotes expression of an epithelial phenotype; triggers de novo formation of functional tight junctions; and contributes to epithelial cell polarity. In particular, HNF4alpha dysfunction leads to metabolic disorders, including diabetes. We used the chromatin immunoprecipitation (ChIP) cloning procedure and a bioinformatic approach to search for candidate genes associated with impaired liver, pancreas, and kidney function. We identified two novel targets regulated by HNF4alpha, which participate in the control, at least in part, in cell-cycle regulation and are members of the mitogen-activated kinase pathway. In multiple ChIP assays, ribosomal S6 kinase 4 (RSK4) and p21-activated kinase 5 (PAK5) were confirmed, and in vitro binding of HNF4alpha was evidenced by electrophoretic mobility shift assays (EMSA) using oligonucleotides, which harbor novel binding sites. We also used EMSA to probe for binding sites in promoters of HNF1alpha, apolipoprotein B, alpha1-antitrypsin, and angiotensinogen. We further studied RSK4 and PAK5 kinase expression in streptozotocin-induced diabetic rat kidney and brain and observed significant repression of HNF4alpha, RSK4, and PAK5 as determined by quantitative real-time reverse transcriptase-polymerase chain reaction. RSK4 and PAK5 may provide a molecular rationale for late-stage complications in disease, and further studies are warranted to explore these targets for the treatment of diabetic nephro- and neuropathy, frequently seen in patients with HNF4alpha dysfunction.
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Affiliation(s)
- Monika Niehof
- Fraunhofer Institute of Toxicology and Experimental Medicine, Center for Drug Research and Medical Biotechnology, Nikolai-Fuchs-Str. 1, 30625 Hannover, Germany
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20
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Schrem H, Klempnauer J, Borlak J. Liver-enriched transcription factors in liver function and development. Part II: the C/EBPs and D site-binding protein in cell cycle control, carcinogenesis, circadian gene regulation, liver regeneration, apoptosis, and liver-specific gene regulation. Pharmacol Rev 2004; 56:291-330. [PMID: 15169930 DOI: 10.1124/pr.56.2.5] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In the first part of our review (see Pharmacol Rev 2002;54:129-158), we discussed the basic principles of gene transcription and the complex interactions within the network of hepatocyte nuclear factors, coactivators, ligands, and corepressors in targeted liver-specific gene expression. Now we summarize the role of basic region/leucine zipper protein family members and particularly the albumin D site-binding protein (DBP) and the CAAT/enhancer-binding proteins (C/EBPs) for their importance in liver-specific gene expression and their role in liver function and development. Specifically, regulatory networks and molecular interactions were examined in detail, and the experimental findings summarized in this review point to pivotal roles of DBP and C/EBPs in cell cycle control, carcinogenesis, circadian gene regulation, liver regeneration, apoptosis, and liver-specific gene regulation. These regulatory proteins are therefore of great importance in liver physiology, liver disease, and liver development. Furthermore, interpretation of the vast data generated by novel genomic platform technologies requires a thorough understanding of regulatory networks and particularly the hierarchies that govern transcription and translation of proteins as well as intracellular protein modifications. Thus, this review aims to stimulate discussions on directions of future research and particularly the identification of molecular targets for pharmacological intervention of liver disease.
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Affiliation(s)
- Harald Schrem
- Center for Drug Research and Medical Biotechnology, Fraunhofer Institut für Toxikologie und Experimentelle Medizin, Nicolai Fuchs Str. 1, 30625 Hannover, Germany
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21
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Borlak J, Klutcka T. Expression of basolateral and canalicular transporters in rat liver and cultures of primary hepatocytes. Xenobiotica 2004; 34:935-47. [PMID: 15801539 DOI: 10.1080/00498250400008363] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Basolateral and canalicular proteins are expressed in the liver and besides their role in the transport of bilirubin, glutathione, hormones and various glucuronides, they also function as transporters of a wide range of drugs. Despite their frequent use in drug research, little is known about the expression of genes coding for transporters in cultures of primary sandwiched hepatocytes. The kinetics of gene expression of canalicular and basolateral membrane transporters in cultures of primary rat sandwiched hepatocytes were investigated, and the expression of cMOAT, spgp, mdrla and mdr2 were shown to be comparable with transcript levels observed in vivo. Strikingly, expression of the basolateral membrane transporter ntcp and oatpl and 2 were dramatically reduced, the level being < 10 and < 5%, respectively, of those found in vivo in rat liver tissue. Notably, mRNA expression of the canalicular membrane transporter mdrlb was increased up to 13-fold. The findings point to a dramatic change in the expression of basolateral and canalicular transporters in cultured hepatocytes, and this should be considered when hepatocytes are used for drug profiling studies.
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Affiliation(s)
- J Borlak
- Fraunhofer Institute of Toxicology and Experimental Medicine, Center for Drug Research and Medical Biotechnology, Nikolai-Fuchs-Str. 1, D-30625 Hannover, Germany.
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22
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Yu CT, Chen J, Teng XW, Tong V, Chang TKH. Lack of evidence for induction of CYP2B1, CYP3A23, and CYP1A2 gene expression by Panax ginseng and Panax quinquefolius extracts in adult rats and primary cultures of rat hepatocytes. Drug Metab Dispos 2004; 33:19-22. [PMID: 15466162 DOI: 10.1124/dmd.104.001917] [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] [Indexed: 01/09/2023] Open
Abstract
Treatment of rats with a single oral dose (10-30 mg/kg) of a crude Panax ginseng extract of unknown ginsenoside content has been reported to modestly increase hepatic microsomal cytochrome P450-mediated aminopyrine N-demethylation activity. In the present study, we compared the effect of P. ginseng and Panax quinquefolius extracts on rat hepatic CYP2B1, CYP3A23, and CYP1A2 gene expression. Adult male Sprague-Dawley rats (250-275 g) received, by oral gavage or i.p., P. ginseng extract [4% (w/w) total ginsenosides; 30 or 100 mg/kg/day for 1 or 4 days], P. quinquefolius extract [10% (w/w) total ginsenosides; 100 or 400 mg/kg/day for 21 consecutive days), or an equivalent volume (2 ml/kg) of the vehicle (0.9% NaCl or 0.3% carboxymethylcellulose) and were terminated 1 day after the last dose. P. ginseng and P. quinquefolius extracts did not affect body weight gain, absolute or relative liver weight, hepatic CYP2B1, CYP3A23, or CYP1A2 mRNA expression, or microsomal CYP2B-mediated 7-benzyloxyresorufin O-dealkylation (BROD) or CYP1A-mediated 7-ethoxyresorufin O-dealkylation (EROD) activity. In contrast, results from positive control experiments indicated that phenobarbital increased CYP2B1 mRNA and BROD activity, dexamethasone increased CYP3A23 mRNA, and beta-naphthoflavone increased CYP1A2 mRNA and EROD activity levels. Treatment of primary cultures of rat hepatocytes with either of the ginseng extracts (0.1-1000 microg/ml for 2 days) also did not affect CYP2B1 or CYP3A23 mRNA expression. Overall, our data indicate that P. ginseng and P. quinquefolius extracts do not increase rat hepatic CYP2B1, CYP3A23, or CYP1A2 gene expression.
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Affiliation(s)
- Chia-Ting Yu
- Faculty of Pharmaceutical Sciences, The University of British Columbia, 2146 East Mall, Vancouver, B. C. V6T 1Z3, Canada
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23
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Park IN, Cho IJ, Kim SG. Ceramide negatively regulates glutathione S-transferase gene transactivation via repression of hepatic nuclear factor-1 that is degraded by the ubiquitin proteasome system. Mol Pharmacol 2004; 65:1475-84. [PMID: 15155840 DOI: 10.1124/mol.65.6.1475] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The level of cellular ceramide, an apoptotic rheostat, is increased by sphingomyelinase or de novo synthesis. The expression of the glutathione S-transferase (GST) gene, whose induction accounts for cell viability, is regulated by activation of CCAAT/enhancer binding protein-beta (C/EBPbeta) and NF-E2-related factor-2 (Nrf2). Hepatic nuclear factor-1 (HNF1) is a transcription factor necessary for cell survival. This study investigated the role of HNF1 in GSTA2 gene transactivation, the ubiquitin proteasomal degradation of HNF1, and the inhibition of activating HNF1 by ceramide for GSTA2 repression. C2-ceramide (C2), a cell-permeable analog, repressed the GSTA2 expression in H4IIE cells, whereas dihydro-C2, an inactive analog, had no effect. Immunoblot, immunocytochemical, and gel shift analyses revealed that C2 decreased the level of nuclear HNF1 and protein binding to the HNF response element (HRE). Deletion of the HRE or the GSTA2 gene promoter region containing the HRE reduced luciferase reporter expression. Immunoprecipitation and immunoblot analyses showed that C2 decreased the level of ubiquitinated HNF1, which was reversed by treatment with MG132, a proteasome inhibitor. C2 suppressed GSTA2 induction by oltipraz via inhibition of inducible HNF1 DNA binding. The functional role of HRE for C2 repression of GSTA2 gene transactivation by oltipraz was verified by both the luciferase reporter gene expression and the transfection experiment with DeltaHNF-pGL-1651 lacking the HRE. C2 similarly repressed the induction of GSTA2 promoter-luciferase by tert-butylhydroquinone via HNF1 suppression, suggesting that constitutive HNF1 activation is required for GSTA2 induction. C2 also inhibited GSTA3/5 expression. In conclusion, the HRE in the GSTA2 promoter region is functionally active for the constitutive and inducible gene expression, and ceramide inhibits GST gene transactivation through decrease in nuclear HNF1, which is degraded by the ubiquitin proteasome system.
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Affiliation(s)
- I-Na Park
- National Research Laboratory, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, South Korea
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24
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Garçon G, Gosset P, Zerimech F, Grave-Descampiaux B, Shirali P. Effect of Fe2O3 on the capacity of benzo(a)pyrene to induce polycyclic aromatic hydrocarbon-metabolizing enzymes in the respiratory tract of Sprague–Dawley rats. Toxicol Lett 2004; 150:179-89. [PMID: 15093673 DOI: 10.1016/j.toxlet.2004.01.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2003] [Revised: 12/18/2003] [Accepted: 01/19/2004] [Indexed: 11/21/2022]
Abstract
In this work, the question that needs to be answered was whether concurrent exposure to iron oxides and polycyclic aromatic hydrocarbons (PAHs) could affect the induction of PAH-metabolizing enzymes. Male Sprague-Dawley rats were intratracheally instilled with hematite (Fe(2)O(3); 3mg), benzo(a)pyrene (B(a)P; 3mg), or B(a)P (3mg)-coated onto Fe(2)O(3) particles (3mg). Forty-eight hours later, we investigated mRNA expressions of cytochrome p4501a1 (cyp1a1), microsomal epoxide hydrolase (meh), and glutathione-S-transferase-ya and -yc (gst-ya and gst-yc, respectively), protein concentrations of CYP1A1, and 7-ethoxyresorufin O-deethylase (EROD) activities in lungs. Exposure to B(a)P alone or coated-onto Fe(2)O(3) particles induced cyp1a1 gene transcription (P < 0.01) and increased both the CYP1A1 protein levels (P < 0.01) and the EROD activities (P < 0.001). However, in this work, we focused our attention on the potential of Fe(2)O(3) in B(a)P/Fe(2)O(3) mixtures to affect the capacity of B(a)P to induce PAH-metabolizing enzymes. Exposure to B(a)P-coated onto Fe(2)O(3) particles increased meh mRNA expressions (1.15-fold, P < 0.05), CYP1A1 protein concentrations (1.85-fold, P < 0.05), and EROD activities (1.95-fold, P < 0.01), versus exposure to B(a)P alone. Hence, animal short-term exposure to B(a)P-coated onto Fe(2)O(3) particles favored dramatically the induction of PAH-bioactivating enzymes to the detriment of PAH-inactivating enzymes in lungs. Taken together, these results support the hypothesis that the Fe(2)O(3)-induced increase of the metabolic activation of B(a)P might rely on several properties of Fe(2)O(3), including its capacity to enhance the rate of CYP1A1 hemoprotein elaboration. The influence of Fe(2)O(3) in B(a)P/Fe(2)O(3) mixtures on the ability of B(a)P to induce PAH-metabolizing enzymes will also be one of the fundamental ways that Fe(2)O(3) can affect B(a)P carcinogenicity in lungs.
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Affiliation(s)
- Guillaume Garçon
- Laboratoire de Recherche en Toxicologie Industrielle et Environnementale, Université du Littoral-Côte d'Opale 220, Avenue de l'Université, BP 5526, 59379 Dunkerque Cedex 1, France
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25
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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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26
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Chana A, Concejero MA, de Frutos M, González MJ, Herradón B. Computational studies on biphenyl derivatives. Analysis of the conformational mobility, molecular electrostatic potential, and dipole moment of chlorinated biphenyl: searching for the rationalization of the selective toxicity of polychlorinated biphenyls (PCBs). Chem Res Toxicol 2002; 15:1514-26. [PMID: 12482233 DOI: 10.1021/tx025596d] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
With the objective to understand how the pattern and degree of chlorination influence on the properties of the title molecules, a computational study on biphenyl and all the chlorinated biphenyls (from 1 to 10 chlorine atoms, 209 congeners) has been undertaken. The study includes conformational searches (and further refinement by molecular dynamics simulations) and the ab initio calculation of the molecular electrostatic potential (MEP) and the dipole moments for all the congeners. The most significant property is the MEP, finding a good correlation between the MEPs and the substitution pattern on chlorinated biphenyls. The most toxic congeners possess highly positive values of electrostatic potential on the aromatic rings and highly negative values of electrostatic potential on the chlorine atoms. Additionally, we have found that the toxic congeners possess conformations with low dipole moments, a fact that may be linked to the ready accumulation on the adipose tissue. The results on the geometry and electrostatic properties of chlorinated biphenyls can be useful to rationalize their selective toxicities.
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Affiliation(s)
- Antonio Chana
- Instituto de Química Orgánica General, Consejo Superior de Investigaciones Científicas, Juan de la Cierva 3, 28006 Madrid, Spain
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27
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Borlak J, Thum T. PCBs alter gene expression of nuclear transcription factors and other heart-specific genes in cultures of primary cardiomyocytes: possible implications for cardiotoxicity. Xenobiotica 2002; 32:1173-83. [PMID: 12593764 DOI: 10.1080/0049825021000022311] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
1. Polychlorinated biphenyls (PCBs) are well-known environmental pollutants that bioaccumulate mainly in the fatty tissue of animals and humans. Although contamination occurs primarily via the food chain, waste combustion leads to airborne PCBs. From epidemiological studies, there is substantial evidence that cardiovascular disease is linked to air pollution, but little is known about the underlying molecular events. 2. We investigated the effects of Aroclor 1254, a complex mixture of >80 PCB isomers and congeners, on the expression of nuclear transcription factors (GATA-4, Nkx-2.5, MEF-2c, OCT-1) and of downstream target genes (atrial and brain natriuretic peptide, alpha- and beta-myosin heavy chain, alpha-cardiac and alpha-skeletal actin), which play an important role in cardiac biology. 3. We treated cultures of primary cardiomyocytes of adult rats with Aroclor 1254 (10.0 micro M) and found significant induction of the transcription factor genes GATA-4 and MEF-2c and of genes regulated by these factors, i.e. atrial natriuretic peptide, brain-type natriuretic peptide, alpha- and beta-myosin heavy chain, and skeletal alpha actin. 4. We have shown PCBs to modulate expression of genes coding for programmes of cellular differentiation and stress (e.g. atrial natriuretic peptide, brain-type natriuretic peptide) and these alterations may be important in the increase of cardiovascular disease in polluted areas.
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Affiliation(s)
- J Borlak
- Fraunhofer Institute of Toxicology and Aerosol Research, Center for Drug Research and Medical Biotechnology, Nicolai-Fuchs-Str. 1, D-30625 Hannover, Germany.
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28
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Abstract
Cytochrome P450 mono-oxygenases (CYP) play an essential role in steroid metabolism, and there is speculation that sex hormones might influence cardiac mass and physiology. As CYP mono-oxygenases activity is frequently altered during disease, we tested our hypothesis that CYP mono-oxygenase expression and testosterone metabolism are altered in cardiac hypertrophy. We investigate major CYP mono-oxygenase isoforms and other steroid-metabolizing enzymes and the androgen receptor in normal, hypertrophic, and assist device-supported human hearts and in spontaneously hypertensive rats (SHR). We show increased and idiosyncratic metabolism of testosterone in hypertrophic heart and link these changes to altered CYP mono-oxygenase expression. We show significant induction of 5-alpha steroid reductase and P450 aromatase gene expression and enhanced production of dihydrotestosterone, which can be inhibited by the 5-alpha reductase inhibitor finasteride. We show increased gene expression of the androgen receptor and increased levels of lipid peroxidation in diseased hearts, the latter being markedly inhibited by CYP mono-oxygenase inactivation. We show alpha-MHC to be significantly repressed in cardiac hypertrophy and restored to normal on testosterone supplementation. We conclude that heart-specific steroid metabolism is of critical importance in cardiac hypertrophy
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Affiliation(s)
- Thomas Thum
- Center of Drug Research and Medical Biotechnology, Fraunhofer Institute of Toxicology and Aerosol Research, Hannover, Germany
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29
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Borlak J, Dangers M, Thum T. Aroclor 1254 modulates gene expression of nuclear transcription factors: implications for albumin gene transcription and protein synthesis in rat hepatocyte cultures. Toxicol Appl Pharmacol 2002; 181:79-88. [PMID: 12051991 DOI: 10.1006/taap.2002.9392] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human exposure to polychlorinated biphenyls (PCBs) may lead to increased albumin serum levels, but little is known about the underlying events. Certain PCBs are also ligands for the aryl hydrocarbon receptor (Ahr) and this receptor regulates transcriptional activation of many different genes, including CYP1A1. We tested our hypothesis that expression of certain nuclear transcription factors is altered upon treatment of rat hepatocyte cultures with Aroclor 1254 and we studied the gene expression of albumin and liver-enriched transcription factors simultaneously. We correlate albumin gene expression with protein synthesis and we used CYP1A1 gene expression and enzyme activity as a surrogate endpoint for aryl hydrocarbon receptor activation. We found mRNA transcripts of CCAAT/enhancer binding protein alpha and gamma, hepatic nuclear factor 1, and hepatic nuclear factor 4 to be increased up to 62-fold, whereas albumin gene expression and secretion was increased 3-fold. Noticeably, expression of c-fos, c-jun (AP-1), HNF-6, CCAAT/enhancer binding protein beta and delta, tissue-specific enhancer-1, Ah-receptor, and albumin D-site-binding protein was unchanged. We show coordinate albumin gene expression and protein secretion in primary rat hepatocyte cultures and propose a relationship between induction of certain liver-enriched transcription factors and of the albumin gene via an Ahr-mediated mechanism.
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Affiliation(s)
- Jürgen Borlak
- Center for Drug Research and Medical Biotechnology, Fraunhofer Institute of Toxicology and Aerosol Research, Germany.
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Waring JF, Jolly RA, Ciurlionis R, Lum PY, Praestgaard JT, Morfitt DC, Buratto B, Roberts C, Schadt E, Ulrich RG. Clustering of hepatotoxins based on mechanism of toxicity using gene expression profiles. Toxicol Appl Pharmacol 2001; 175:28-42. [PMID: 11509024 DOI: 10.1006/taap.2001.9243] [Citation(s) in RCA: 295] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Microarray technology, which allows one to quantitate the expression of thousands of genes simultaneously, has begun to have a major impact on many different areas of drug discovery and development. The question remains of whether microarray analysis and gene expression signature profiles can be applied to the field of toxicology. To date, there are very few published studies showing the use of microarrays in toxicology and important questions remain regarding the predictability and accuracy of applying gene expression profiles to toxicology. To begin to address these questions, we have treated rats with 15 different known hepatotoxins, including allyl alcohol, amiodarone, Aroclor 1254, arsenic, carbamazepine, carbon tetrachloride, diethylnitrosamine, dimethylformamide, diquat, etoposide, indomethacin, methapyrilene, methotrexate, monocrotaline, and 3-methylcholanthrene. These agents cause a variety of hepatocellular injuries including necrosis, DNA damage, cirrhosis, hypertrophy, and hepatic carcinoma. Gene expression analysis was done on RNA from the livers of treated rats and was compared against vehicle-treated controls. The gene expression results were clustered and compared to the histopathology findings and clinical chemistry values. Our results show strong correlation between the histopathology, clinical chemistry, and gene expression profiles induced by the agents. In addition, genes were identified whose regulation correlated strongly with effects on clinical chemistry parameters. Overall, the results suggest that microarray assays may prove to be a highly sensitive technique for safety screening of drug candidates and for the classification of environmental toxins.
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Affiliation(s)
- J F Waring
- Department of Cellular and Molecular Toxicology, Abbott Laboratories, Abbott Park, Illinois 60064-6104, USA.
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