2013
Procházková, Jiřina; Kabátková, Markéta; Šmerdová, Lenka; Pacherník, Jiří; Sykorová, Dominika; Kohoutek, Jiří; Šimečková, Pavlína; Hrubá, Eva; Kozubík, Alois; Machala, Miroslav; Vondráček, Jan
Aryl hydrocarbon receptor negatively regulates expression of the plakoglobin gene (jup). Journal Article
In: Toxicological sciences : an official journal of the Society of Toxicology, vol. 134, no. 2, pp. 258–270, 2013, ISSN: 1096-0929, (Place: United States).
Abstract | Links | BibTeX | Tags: Animals, Aryl hydrocarbon receptor, Aryl Hydrocarbon/*physiology, Base Sequence, cardiomyocytes., Cell Adhesion, Cell Line, Cell Proliferation, Cloning, desmosomes, dioxin, DNA Primers, Down-Regulation, gamma Catenin/*genetics, Gene Expression Regulation/*physiology, Genetic, Inbred F344, liver progenitor cells, Molecular, plakoglobin, Polychlorinated Dibenzodioxins/pharmacology, Promoter Regions, Rats, Real-Time Polymerase Chain Reaction, Receptors
@article{prochazkova_aryl_2013,
title = {Aryl hydrocarbon receptor negatively regulates expression of the plakoglobin gene (jup).},
author = {Jiřina Procházková and Markéta Kabátková and Lenka Šmerdová and Jiří Pacherník and Dominika Sykorová and Jiří Kohoutek and Pavlína Šimečková and Eva Hrubá and Alois Kozubík and Miroslav Machala and Jan Vondráček},
doi = {10.1093/toxsci/kft110},
issn = {1096-0929},
year = {2013},
date = {2013-08-01},
journal = {Toxicological sciences : an official journal of the Society of Toxicology},
volume = {134},
number = {2},
pages = {258–270},
abstract = {Plakoglobin is an important component of intercellular junctions, including both desmosomes and adherens junctions, which is known as a tumor suppressor. Although mutations in the plakoglobin gene (Jup) and/or changes in its protein levels have been observed in various disease states, including cancer progression or cardiovascular defects, the information about endogenous or exogenous stimuli orchestrating Jup expression is limited. Here we show that the aryl hydrocarbon receptor (AhR) may regulate Jup expression in a cell-specific manner. We observed a significant suppressive effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a model toxic exogenous activator of the AhR signaling, on Jup expression in a variety of experimental models derived from rodent tissues, including contact-inhibited rat liver progenitor cells (where TCDD induces cell proliferation), rat and mouse hepatoma cell models (where TCDD inhibits cell cycle progression), cardiac cells derived from the mouse embryonic stem cells, or cardiomyocytes isolated from neonatal rat hearts. The small interfering RNA (siRNA)-mediated knockdown of AhR confirmed its role in both basal and TCDD-deregulated Jup expression. The analysis of genomic DNA located textasciitilde2.5kb upstream of rat Jup gene revealed a presence of evolutionarily conserved AhR binding motifs, which were confirmed upon their cloning into luciferase reporter construct. The siRNA-mediated knockdown of Jup expression affected both proliferation and attachment of liver progenitor cells. The present data indicate that the AhR may contribute to negative regulation of Jup gene expression in rodent cellular models, which may affect cell adherence and proliferation.},
note = {Place: United States},
keywords = {Animals, Aryl hydrocarbon receptor, Aryl Hydrocarbon/*physiology, Base Sequence, cardiomyocytes., Cell Adhesion, Cell Line, Cell Proliferation, Cloning, desmosomes, dioxin, DNA Primers, Down-Regulation, gamma Catenin/*genetics, Gene Expression Regulation/*physiology, Genetic, Inbred F344, liver progenitor cells, Molecular, plakoglobin, Polychlorinated Dibenzodioxins/pharmacology, Promoter Regions, Rats, Real-Time Polymerase Chain Reaction, Receptors},
pubstate = {published},
tppubtype = {article}
}
Plakoglobin is an important component of intercellular junctions, including both desmosomes and adherens junctions, which is known as a tumor suppressor. Although mutations in the plakoglobin gene (Jup) and/or changes in its protein levels have been observed in various disease states, including cancer progression or cardiovascular defects, the information about endogenous or exogenous stimuli orchestrating Jup expression is limited. Here we show that the aryl hydrocarbon receptor (AhR) may regulate Jup expression in a cell-specific manner. We observed a significant suppressive effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a model toxic exogenous activator of the AhR signaling, on Jup expression in a variety of experimental models derived from rodent tissues, including contact-inhibited rat liver progenitor cells (where TCDD induces cell proliferation), rat and mouse hepatoma cell models (where TCDD inhibits cell cycle progression), cardiac cells derived from the mouse embryonic stem cells, or cardiomyocytes isolated from neonatal rat hearts. The small interfering RNA (siRNA)-mediated knockdown of AhR confirmed its role in both basal and TCDD-deregulated Jup expression. The analysis of genomic DNA located textasciitilde2.5kb upstream of rat Jup gene revealed a presence of evolutionarily conserved AhR binding motifs, which were confirmed upon their cloning into luciferase reporter construct. The siRNA-mediated knockdown of Jup expression affected both proliferation and attachment of liver progenitor cells. The present data indicate that the AhR may contribute to negative regulation of Jup gene expression in rodent cellular models, which may affect cell adherence and proliferation.
2011
Procházková, Jirina; Kabátková, Markéta; Bryja, Vítezslav; Umannová, Lenka; Bernatík, Ondrej; Kozubík, Alois; Machala, Miroslav; Vondrácek, Jan
In: Toxicological sciences : an official journal of the Society of Toxicology, vol. 122, no. 2, pp. 349–360, 2011, ISSN: 1096-0929, (Place: United States).
Abstract | Links | BibTeX | Tags: Animals, Aryl Hydrocarbon Hydroxylases/genetics/metabolism, Aryl Hydrocarbon/genetics/*metabolism, beta Catenin/genetics/*metabolism, Cadherins/genetics, Cell Adhesion, Cell Differentiation, Cell Line, Cytochrome P-450 CYP1A1/genetics/metabolism, Cytochrome P-450 CYP1B1, Down-Regulation/drug effects, Hepatocytes/drug effects, Inbred F344, Liver/*drug effects, Polychlorinated Dibenzodioxins/toxicity, Rats, Receptors, Wnt Proteins/genetics/*metabolism, Wnt Signaling Pathway
@article{prochazkova_interplay_2011,
title = {The interplay of the aryl hydrocarbon receptor and β-catenin alters both AhR-dependent transcription and Wnt/β-catenin signaling in liver progenitors.},
author = {Jirina Procházková and Markéta Kabátková and Vítezslav Bryja and Lenka Umannová and Ondrej Bernatík and Alois Kozubík and Miroslav Machala and Jan Vondrácek},
doi = {10.1093/toxsci/kfr129},
issn = {1096-0929},
year = {2011},
date = {2011-08-01},
journal = {Toxicological sciences : an official journal of the Society of Toxicology},
volume = {122},
number = {2},
pages = {349–360},
abstract = {β-catenin is a key integrator of cadherin-mediated cell-cell adhesion and transcriptional regulation through the Wnt/β-catenin pathway, which plays an important role in liver biology. Using a model of contact-inhibited liver progenitor cells, we examined the interactions of Wnt/β-catenin signaling with the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, which mediates the toxicity of dioxin-like compounds, including their effects on development and hepatocarcinogenesis. We found that AhR and Wnt/β-catenin cooperated in the induction of AhR transcriptional targets, such as Cyp1a1 and Cyp1b1. However, simultaneously, the activation of AhR led to a decrease of dephosphorylated active β-catenin pool, as well as to hypophosphorylation of Dishevelled, participating in regulation of Wnt signaling. A sustained AhR activation by its model ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), led to a downregulation of a number of Wnt/β-catenin pathway target genes. TCDD also induced a switch in cytokeratin expression, where downregulation of cytokeratins 14 and 19 was accompanied with an increased cytokeratin 8 expression. Together with a downregulation of additional markers associated with stem-like phenotype, this indicated that the AhR activation interfered with differentiation of liver progenitors. The downregulation of β-catenin was also related to a reduced cell adhesion, disruption of E-cadherin-mediated cell-cell junctions and an increased G1-S transition in liver progenitor cell line. In conclusion, although β-catenin augmented the expression of selected AhR target genes, the persistent AhR activation may lead to downregulation of Wnt/β-catenin signaling, thus altering differentiation and/or proliferative status of liver progenitor cells.},
note = {Place: United States},
keywords = {Animals, Aryl Hydrocarbon Hydroxylases/genetics/metabolism, Aryl Hydrocarbon/genetics/*metabolism, beta Catenin/genetics/*metabolism, Cadherins/genetics, Cell Adhesion, Cell Differentiation, Cell Line, Cytochrome P-450 CYP1A1/genetics/metabolism, Cytochrome P-450 CYP1B1, Down-Regulation/drug effects, Hepatocytes/drug effects, Inbred F344, Liver/*drug effects, Polychlorinated Dibenzodioxins/toxicity, Rats, Receptors, Wnt Proteins/genetics/*metabolism, Wnt Signaling Pathway},
pubstate = {published},
tppubtype = {article}
}
β-catenin is a key integrator of cadherin-mediated cell-cell adhesion and transcriptional regulation through the Wnt/β-catenin pathway, which plays an important role in liver biology. Using a model of contact-inhibited liver progenitor cells, we examined the interactions of Wnt/β-catenin signaling with the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, which mediates the toxicity of dioxin-like compounds, including their effects on development and hepatocarcinogenesis. We found that AhR and Wnt/β-catenin cooperated in the induction of AhR transcriptional targets, such as Cyp1a1 and Cyp1b1. However, simultaneously, the activation of AhR led to a decrease of dephosphorylated active β-catenin pool, as well as to hypophosphorylation of Dishevelled, participating in regulation of Wnt signaling. A sustained AhR activation by its model ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), led to a downregulation of a number of Wnt/β-catenin pathway target genes. TCDD also induced a switch in cytokeratin expression, where downregulation of cytokeratins 14 and 19 was accompanied with an increased cytokeratin 8 expression. Together with a downregulation of additional markers associated with stem-like phenotype, this indicated that the AhR activation interfered with differentiation of liver progenitors. The downregulation of β-catenin was also related to a reduced cell adhesion, disruption of E-cadherin-mediated cell-cell junctions and an increased G1-S transition in liver progenitor cell line. In conclusion, although β-catenin augmented the expression of selected AhR target genes, the persistent AhR activation may lead to downregulation of Wnt/β-catenin signaling, thus altering differentiation and/or proliferative status of liver progenitor cells.