101
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Highlight report: cytoprotective signaling in toxicology. Arch Toxicol 2015; 89:2189-91. [PMID: 26525396 DOI: 10.1007/s00204-015-1628-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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102
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Rondini EA, Pant A, Kocarek TA. Transcriptional Regulation of Cytosolic Sulfotransferase 1C2 by Intermediates of the Cholesterol Biosynthetic Pathway in Primary Cultured Rat Hepatocytes. J Pharmacol Exp Ther 2015; 355:429-41. [PMID: 26427720 DOI: 10.1124/jpet.115.226365] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 09/30/2015] [Indexed: 01/19/2023] Open
Abstract
Cytosolic sulfotransferase 1C2 (SULT1C2) is expressed in the kidney, stomach, and liver of rats; however, the mechanisms regulating expression of this enzyme are not known. We evaluated transcriptional regulation of SULT1C2 by mevalonate (MVA)-derived intermediates in primary cultured rat hepatocytes using several cholesterol synthesis inhibitors. Blocking production of mevalonate with the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor pravastatin (30 μM), reduced SULT1C2 mRNA content by ∼40% whereas the squalene synthase inhibitor squalestatin (SQ1, 0.1 μM), which causes accumulation of nonsterol isoprenoids, increased mRNA content by 4-fold. Treatment with MVA (10 mM) strongly induced SULT1C2 mRNA by 12-fold, and this effect was blocked by inhibiting squalene epoxidase but not by more distal cholesterol inhibitors, indicating the effects of MVA are mediated by postsqualene metabolites. Using rapid amplification of cDNA ends (RACE), we characterized the 5' end of SULT1C2 mRNA and used this information to generate constructs for promoter analysis. SQ1 and MVA increased reporter activity by ∼1.6- and 3-fold, respectively, from a construct beginning 49 base pairs (bp) upstream from the longest 5'-RACE product (-3140:-49). Sequence deletions from this construct revealed a hepatocyte nuclear factor 1 (HNF1) element (-2558), and mutation of this element reduced basal (75%) and MVA-induced (30%) reporter activity and attenuated promoter activation following overexpression of HNF1α or 1β. However, the effects of SQ1 were localized to a more proximal promoter region (-281:-49). Collectively, our findings demonstrate that cholesterol biosynthetic intermediates influence SULT1C2 expression in rat primary hepatocytes. Further, HNF1 appears to play an important role in mediating basal and MVA-induced SULT1C2 transcription.
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Affiliation(s)
- Elizabeth A Rondini
- Institute of Environmental Health Sciences, Wayne State University, Detroit, Michigan
| | - Asmita Pant
- Institute of Environmental Health Sciences, Wayne State University, Detroit, Michigan
| | - Thomas A Kocarek
- Institute of Environmental Health Sciences, Wayne State University, Detroit, Michigan
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103
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Ghallab A. Highlight report: perspectives in stem cell research--unbiased quantification of the similarity between in vitro generated and primary hepatocytes. Arch Toxicol 2015; 89:2185-7. [PMID: 26410582 DOI: 10.1007/s00204-015-1597-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 09/08/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Ahmed Ghallab
- Forensic Medicine and Toxicology Department, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt.
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104
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Ghallab A. Highlight report: Blueprint for stem cell differentiation into liver cells. EXCLI JOURNAL 2015; 14:1017-9. [PMID: 26648827 PMCID: PMC4669944 DOI: 10.17179/excli2015-549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 09/01/2015] [Indexed: 11/23/2022]
Affiliation(s)
- Ahmed Ghallab
- Forensic Medicine and Toxicology Department, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt
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105
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Gene expression and pathway analysis of human hepatocellular carcinoma cells treated with cadmium. Toxicol Appl Pharmacol 2015; 288:399-408. [PMID: 26314618 DOI: 10.1016/j.taap.2015.08.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 08/14/2015] [Accepted: 08/18/2015] [Indexed: 12/12/2022]
Abstract
Cadmium (Cd) is a toxic and carcinogenic metal naturally occurring in the Earth's crust. A common route of human exposure is via diet and cadmium accumulates in the liver. The effects of Cd exposure on gene expression in human hepatocellular carcinoma (HepG2) cells were examined in this study. HepG2 cells were acutely-treated with 0.1, 0.5, or 1.0 μM Cd for 24h; or chronically-treated with 0.01, 0.05, or 0.1 μM Cd for three weeks and gene expression analysis was performed using Affymetrix GeneChip® Human Gene 1.0 ST Arrays. Acute and chronic exposures significantly altered the expression of 333 and 181 genes, respectively. The genes most upregulated by acute exposure included several metallothioneins. Downregulated genes included the monooxygenase CYP3A7, involved in drug and lipid metabolism. In contrast, CYP3A7 was upregulated by chronic Cd exposure, as was DNAJB9, an anti-apoptotic J protein. Genes downregulated following chronic exposure included the transcriptional regulator early growth response protein 1. Ingenuity Pathway Analysis revealed that the top networks altered by acute exposure were lipid metabolism, small molecule biosynthesis, cell morphology, organization, and development; while top networks altered by chronic exposure were organ morphology, cell cycle, cell signaling, and renal and urological diseases/cancer. Many of the dysregulated genes play important roles in cellular growth, proliferation, and apoptosis, and may be involved in carcinogenesis. In addition to gene expression changes, HepG2 cells treated with cadmium for 24h indicated a reduction in global levels of histone methylation and acetylation that persisted 72 h post-treatment.
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106
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Rempel E, Hoelting L, Waldmann T, Balmer NV, Schildknecht S, Grinberg M, Das Gaspar JA, Shinde V, Stöber R, Marchan R, van Thriel C, Liebing J, Meisig J, Blüthgen N, Sachinidis A, Rahnenführer J, Hengstler JG, Leist M. A transcriptome-based classifier to identify developmental toxicants by stem cell testing: design, validation and optimization for histone deacetylase inhibitors. Arch Toxicol 2015; 89:1599-618. [PMID: 26272509 PMCID: PMC4551554 DOI: 10.1007/s00204-015-1573-y] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 07/22/2015] [Indexed: 12/17/2022]
Abstract
Test systems to identify developmental toxicants are urgently needed. A combination of human stem cell technology and transcriptome analysis was to provide a proof of concept that toxicants with a related mode of action can be identified and grouped for read-across. We chose a test system of developmental toxicity, related to the generation of neuroectoderm from pluripotent stem cells (UKN1), and exposed cells for 6 days to the histone deacetylase inhibitors (HDACi) valproic acid, trichostatin A, vorinostat, belinostat, panobinostat and entinostat. To provide insight into their toxic action, we identified HDACi consensus genes, assigned them to superordinate biological processes and mapped them to a human transcription factor network constructed from hundreds of transcriptome data sets. We also tested a heterogeneous group of ‘mercurials’ (methylmercury, thimerosal, mercury(II)chloride, mercury(II)bromide, 4-chloromercuribenzoic acid, phenylmercuric acid). Microarray data were compared at the highest non-cytotoxic concentration for all 12 toxicants. A support vector machine (SVM)-based classifier predicted all HDACi correctly. For validation, the classifier was applied to legacy data sets of HDACi, and for each exposure situation, the SVM predictions correlated with the developmental toxicity. Finally, optimization of the classifier based on 100 probe sets showed that eight genes (F2RL2, TFAP2B, EDNRA, FOXD3, SIX3, MT1E, ETS1 and LHX2) are sufficient to separate HDACi from mercurials. Our data demonstrate how human stem cells and transcriptome analysis can be combined for mechanistic grouping and prediction of toxicants. Extension of this concept to mechanisms beyond HDACi would allow prediction of human developmental toxicity hazard of unknown compounds with the UKN1 test system.
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Affiliation(s)
- Eugen Rempel
- Department of Statistics, TU Dortmund University, 44139, Dortmund, Germany
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107
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Dreser N, Zimmer B, Dietz C, Sügis E, Pallocca G, Nyffeler J, Meisig J, Blüthgen N, Berthold MR, Waldmann T, Leist M. Grouping of histone deacetylase inhibitors and other toxicants disturbing neural crest migration by transcriptional profiling. Neurotoxicology 2015; 50:56-70. [PMID: 26238599 DOI: 10.1016/j.neuro.2015.07.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 07/28/2015] [Accepted: 07/28/2015] [Indexed: 12/13/2022]
Abstract
Functional assays, such as the "migration inhibition of neural crest cells" (MINC) developmental toxicity test, can identify toxicants without requiring knowledge on their mode of action (MoA). Here, we were interested, whether (i) inhibition of migration by structurally diverse toxicants resulted in a unified signature of transcriptional changes; (ii) whether statistically-identified transcript patterns would inform on compound grouping even though individual genes were little regulated, and (iii) whether analysis of a small group of biologically-relevant transcripts would allow the grouping of compounds according to their MoA. We analyzed transcripts of 35 'migration genes' after treatment with 16 migration-inhibiting toxicants. Clustering, principal component analysis and correlation analyses of the data showed that mechanistically related compounds (e.g. histone deacetylase inhibitors (HDACi), PCBs) triggered similar transcriptional changes, but groups of structurally diverse toxicants largely differed in their transcriptional effects. Linear discriminant analysis (LDA) confirmed the specific clustering of HDACi across multiple separate experiments. Similarity of the signatures of the HDACi trichostatin A and suberoylanilide hydroxamic acid to the one of valproic acid (VPA), suggested that the latter compound acts as HDACi when impairing neural crest migration. In conclusion, the data suggest that (i) a given functional effect (e.g. inhibition of migration) can be associated with highly diverse signatures of transcript changes; (ii) statistically significant grouping of mechanistically-related compounds can be achieved on the basis of few genes with small regulations. Thus, incorporation of mechanistic markers in functional in vitro tests may support read-across procedures, also for structurally un-related compounds.
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Affiliation(s)
- Nadine Dreser
- Doerenkamp-Zbinden Chair of In Vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
| | - Bastian Zimmer
- Center for Stem Cell Biology, Sloan-Kettering Institute, New York City, NY, USA; Developmental Biology Program, Sloan-Kettering Institute, New York City, NY, USA.
| | - Christian Dietz
- Lehrstuhl für Bioinformatik und Information Mining, University of Konstanz, Konstanz, Germany
| | - Elena Sügis
- Institute of Computer Science, University of Tartu, Tartu, Estonia
| | - Giorgia Pallocca
- Doerenkamp-Zbinden Chair of In Vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
| | - Johanna Nyffeler
- Doerenkamp-Zbinden Chair of In Vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
| | - Johannes Meisig
- Institute of Pathology, Charité-Universitätsmedizin, 10117 Berlin, Germany; Integrative Research Institute for the Life Sciences and Institute for Theoretical Biology, Humboldt Universität, 10115 Berlin, Germany
| | - Nils Blüthgen
- Institute of Pathology, Charité-Universitätsmedizin, 10117 Berlin, Germany; Integrative Research Institute for the Life Sciences and Institute for Theoretical Biology, Humboldt Universität, 10115 Berlin, Germany
| | - Michael R Berthold
- Lehrstuhl für Bioinformatik und Information Mining, University of Konstanz, Konstanz, Germany
| | - Tanja Waldmann
- Doerenkamp-Zbinden Chair of In Vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
| | - Marcel Leist
- Doerenkamp-Zbinden Chair of In Vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
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108
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Current research on experimental and applied animal sciences. Arch Toxicol 2015; 89:1149-50. [PMID: 26003615 DOI: 10.1007/s00204-015-1534-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 05/12/2015] [Indexed: 10/23/2022]
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109
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Rahnenführer J, Leist M. From smoking guns to footprints: mining for critical events of toxicity pathways in transcriptome data. Arch Toxicol 2015; 89:813-7. [PMID: 25851820 PMCID: PMC4396704 DOI: 10.1007/s00204-015-1497-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 02/25/2015] [Indexed: 12/23/2022]
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110
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Stöber R. Transcriptome based differentiation of harmless, teratogenetic and cytotoxic concentration ranges of valproic acid. EXCLI JOURNAL 2014; 13:1281-2. [PMID: 26417342 PMCID: PMC4464487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 12/10/2014] [Indexed: 11/16/2022]
Affiliation(s)
- Regina Stöber
- Leibniz Institut für Arbeitsforschung an der TU Dortmund, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystrasse 67, 44139 Dortmund, Germany,*To whom correspondence should be addressed: Regina Stöber, Leibniz Institut für Arbeitsforschung an der TU Dortmund, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystrasse 67, 44139 Dortmund, Germany, E-mail:
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