scholarly journals Natural agonists for aryl hydrocarbon receptor in culture medium are essential for optimal differentiation of Th17 T cells

2008 ◽  
Vol 206 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Marc Veldhoen ◽  
Keiji Hirota ◽  
Jillian Christensen ◽  
Anne O'Garra ◽  
Brigitta Stockinger
Keyword(s):  
Aryl Hydrocarbon Receptor ◽  
Th17 Cells ◽  
Culture Medium ◽  
Transforming Growth Factor ◽  
Aromatic Amino Acids ◽  
Human Cells ◽  
Downstream Target ◽  
Aryl Hydrocarbon ◽  
Relative Paucity

Th17 cell differentiation is dependent on interleukin (IL)-6 and transforming growth factor (TGF)-β, and it is modulated by activation of the aryl hydrocarbon receptor (AhR). In this study, we show that differentiation of Th17 cells, but not Th1 or induced regulatory T (iT reg) cells, is increased by endogenous AhR agonists present in culture medium. Th17 development from wild-type mice is suboptimal in the presence of the AhR antagonist CH-223191, similar to the situation in AhR-deficient mice, which show attenuated IL-17 production and no IL-22 production. The presence of natural AhR agonists in culture medium is also revealed by the induction of CYP1A1, a downstream target of AhR activation. However, the most commonly used medium, RPMI, supports very low levels of Th17 polarization, whereas Iscove's modified Dulbecco's medium, a medium richer in aromatic amino acids, which give rise to AhR agonists, consistently results in higher Th17 expansion in both mouse and human cells. The relative paucity of AhR agonists in RPMI medium, coupled with the presence of factors conducive to IL-2 activation and enhanced Stat5 phosphorylation, conspire against optimal Th17 differentiation. Our data emphasize that AhR activation plays an essential part in the development of Th17 cells and provide a rational explanation for the poor in vitro polarization of Th17 cells that is reported in the majority of publications for both mouse and human cells.

More than a cell biosensor: aryl hydrocarbon receptor at the intersection of physiology and inflammation

2020 ◽  
Vol 318 (6) ◽  
pp. C1078-C1082 ◽  
Author(s):  
Tiziana Guarnieri ◽  
Provvidenza Maria Abruzzo ◽  
Alessandra Bolotta
Keyword(s):  
Aryl Hydrocarbon Receptor ◽  
Inflammatory Mediators ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Downstream Target ◽  
Aryl Hydrocarbon ◽  
Inflammatory State ◽  
A Cell ◽  
The Individual ◽  
Inflammatory Molecules

Aryl hydrocarbon receptor (AhR), a highly conserved intracellular transcription factor, is activated by a plethora of ligands of both exogenous and endogenous nature. Besides activating xenobiotic-metabolizing enzymes, it is involved in the differentiation and development of hematopoietic, hepatic, nervous and immune systems. More and more data describe its role in the regulation of immune responses and in the onset and progression of inflammation. Particularly, established results view AhR as a downstream target of inflammatory molecules, since its transcription is regulated by the inflammatory cascade. Interleukin 6 (IL-6) has been described to sustain early stages of inflammation and to influence the expression of AhR either directly, following signal transducer and activator of transcription 3 (STAT3) activation, or in combination with other inflammatory mediators, e.g., transforming growth factor-β (TGF-β). In selected inflammatory milieus, once activated, AhR interacts with its targets including the IL-6 promoter, thus originating an autoinflammatory loop. This perspective review brings together evidence that, in some IL-6-driven pathways, AhR is a downstream target that amplifies the duration and extent of inflammation. Considering that many inflammatory mediators can also trigger the activities of AhR as biosensor and activator of xenobiotics metabolism, this issue is of pivotal importance. The individual susceptibly to some environmental ligands of AhR can be probably explained by considering the individual inflammatory state, which could additionally fuel the proinflammatory activity of AhR. Thus, AhR could be considered a transductor of a dynamic, bidirectional connection between internal and external environmental stimuli and the inflammatory response.

scholarly journals Disruption of endogenous regulator homeostasis underlies the mechanism of rat CYP1A1 mRNA induction by metyrapone

1998 ◽  
Vol 331 (1) ◽  
pp. 273-281 ◽  
Author(s):  
Joanna L. HARVEY ◽  
Alan J. PAINE ◽  
Matthew C. WRIGHT
Keyword(s):  
Gene Expression ◽  
Glucocorticoid Receptor ◽  
Aryl Hydrocarbon Receptor ◽  
Culture Medium ◽  
Male Rats ◽  
Aryl Hydrocarbon ◽  
Mrna Induction ◽  
Cyp1a1 Gene ◽  
Cyp1a1 Mrna

The transcriptional induction of the cytochrome P-450 1A1 (CYP1A1) gene by xenobiotics such as polyaromatic hydrocarbons is dependent on their interaction with the aryl hydrocarbon receptor. Administration of the structurally unrelated compounds metyrapone (a cytochrome P-450 inhibitor) or dexamethasone (a glucocorticoid) to male rats does not induce hepatic CYP1A1 mRNA. However, administration of both metyrapone and dexamethasone to male rats results in the induction of hepatic CYP1A1 mRNA expression. The induction response is mimicked in vitro in cultured rat hepatocytes by the addition of metyrapone and dexamethasone to a serum-free culture medium, suggesting that these compounds act directly on the liver in vivo to effect hepatic CYP1A1 mRNA induction. An examination of the characteristics of CYP1A1 induction by metyrapone and dexamethasone in combination in vitro indicate that at least 6 h of treatment is required for detectable levels of CYP1A1 mRNA to accumulate in hepatocytes. In contrast, β-naphthoflavone, which is known to bind to the aryl hydrocarbon receptor to effect CYP1A1 gene expression, induces detectable levels of CYP1A1 mRNA within 2 h of treatment. CYP1A1 mRNA is also induced when hepatocytes are treated with metyrapone in combination with the protein synthesis inhibitor cycloheximide but not with dexamethasone in combination with cycloheximide, indicating that CYP1A1 mRNA induction is strictly dependent on the presence of metyrapone and suggesting that the metyrapone-associated induction of CYP1A1 mRNA is dependent on a loss of a constitutively expressed protein that functions to suppress CYP1A1 gene expression. The role of dexamethasone in metyrapone-associated induction of CYP1A1 is probably mediated through the glucocorticoid receptor since the glucocorticoid receptor antagonist RU486 reduces the levels of CYP1A1 mRNA induced by metyrapone and dexamethasone in combination. Increasing the levels of the photosensitizer riboflavin present in the culture medium 10-fold and exposure to light increases the levels of CYP1A1 mRNA induced by metyrapone and dexamethasone in combination in vitro, suggesting that photoactivation of inducing medium constituent(s) might be required for induction. Failure to induce CYP1A1 mRNA by co-administration of metyrapone and dexamethasone in hepatocytes cultured in a balanced salt solution with or without photoactivation indicates that induction is dependent on a photoactivated component of the culture medium and not on metyrapone or dexamethasone alone. The addition of tryptophan in the presence of riboflavin to the balanced salt solution restores CYP1A1 mRNA induction by metyrapone alone and induction is increased when medium is exposed to light, indicating that induction is dependent on tryptophan photoactivation in vitro. Metyrapone failed to compete with 2,3,7,8-tetrachlorodibenzo-p-dioxin for specific binding to the aryl hydrocarbon receptor in rat liver cytosolic fractions. These results suggest that CYP1A1 might be induced in rats by metyrapone through an indirect mechanism associated with an elevation in the level of an endogenously generated inducer such as photoactivated product(s) of tryptophan and not because of metyrapone's interacting with the aryl hydrocarbon receptor. The dependence of CYP1A1 induction on dexamethasone or cycloheximide suggests that derepression by a glucocorticoid receptor-modulated negative-acting factor of CYP1A1 gene expression might be critical to induction by metyrapone.

scholarly journals Generation of IL-8 and IL-9 Producing CD4+T Cells Is Affected by Th17 Polarizing Conditions and AHR Ligands

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Michaela Gasch ◽  
Tina Goroll ◽  
Mario Bauer ◽  
Denise Hinz ◽  
Nicole Schütze ◽  
...  
Keyword(s):  
T Cells ◽  
T Helper Cells ◽  
Th17 Cells ◽  
Immune Cell ◽  
T Helper Cell ◽  
Helper Cell ◽  
T Helper ◽  
Helper Cells ◽  
Aryl Hydrocarbon

The T helper cell subsets Th1, Th2, Th17, and Treg play an important role in immune cell homeostasis, in host defense, and in immunological disorders. Recently, much attention has been paid to Th17 cells which seem to play an important role in the early phase of the adoptive immune response and autoimmune disease. When generating Th17 cells underin vitroconditions the amount of IL-17A producing cells hardly exceeds 20% while the nature of the remaining T cells is poorly characterized. As engagement of the aryl hydrocarbon receptor (AHR) has also been postulated to modulate the differentiation of T helper cells into Th17 cells with regard to the IL-17A expression we ask how far do Th17 polarizing conditions in combination with ligand induced AHR activation have an effect on the production of other T helper cell cytokines. We found that a high proportion of T helper cells cultured under Th17 polarizing conditions are IL-8 and IL-9 single producing cells and that AHR activation results in an upregulation of IL-8 and a downregulation of IL-9 production. Thus, we have identified IL-8 and IL-9 producing T helper cells which are subject to regulation by the engagement of the AHR.

Regulation of cytochrome P450 enzymes by aryl hydrocarbon receptor in human cells

1998 ◽  
Vol 56 (5) ◽  
pp. 599-612 ◽  
Author(s):  
Wei Li ◽  
Patricia A Harper ◽  
Bing-Kou Tang ◽  
Allan B Okey
Keyword(s):  
Cytochrome P450 ◽  
Aryl Hydrocarbon Receptor ◽  
Human Cells ◽  
Cytochrome P450 Enzymes ◽  
Aryl Hydrocarbon

scholarly journals Expression, Localization, and Activity of the Aryl Hydrocarbon Receptor in the Human Placenta

2018 ◽  
Vol 19 (12) ◽  
pp. 3762 ◽  
Author(s):  
Anaïs Wakx ◽  
Margaux Nedder ◽  
Céline Tomkiewicz-Raulet ◽  
Jessica Dalmasso ◽  
Audrey Chissey ◽  
...  
Keyword(s):  
Aryl Hydrocarbon Receptor ◽  
Human Placenta ◽  
Target Genes ◽  
Environmental Pollutants ◽  
Cell Fractionation ◽  
Protein Levels ◽  
Aryl Hydrocarbon ◽  
Epithelial Barriers ◽  
Expression And Activity

The human placenta is an organ between the blood of the mother and the fetus, which is essential for fetal development. It also plays a role as a selective barrier against environmental pollutants that may bypass epithelial barriers and reach the placenta, with implications for the outcome of pregnancy. The aryl hydrocarbon receptor (AhR) is one of the most important environmental-sensor transcription factors and mediates the metabolism of a wide variety of xenobiotics. Nevertheless, the identification of dietary and endogenous ligands of AhR suggest that it may also fulfil physiological functions with which pollutants may interfere. Placental AhR expression and activity is largely unknown. We established the cartography of AhR expression at transcript and protein levels, its cellular distribution, and its transcriptional activity toward the expression of its main target genes. We studied the profile of AhR expression and activity during different pregnancy periods, during trophoblasts differentiation in vitro, and in a trophoblast cell line. Using diverse methods, such as cell fractionation and immunofluorescence microscopy, we found a constitutive nuclear localization of AhR in every placental model, in the absence of any voluntarily-added exogenous activator. Our data suggest an intrinsic activation of AhR due to the presence of endogenous placental ligands.

scholarly journals Hepatitis B Virus X-Associated Protein 2 Is a Subunit of the Unliganded Aryl Hydrocarbon Receptor Core Complex and Exhibits Transcriptional Enhancer Activity

1998 ◽  
Vol 18 (2) ◽  
pp. 978-988 ◽  
Author(s):  
Brian K. Meyer ◽  
Marilyn G. Pray-Grant ◽  
John P. Vanden Heuvel ◽  
Gary H. Perdew
Keyword(s):  
Amino Acid ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Aryl Hydrocarbon Receptor ◽  
In Vitro Translation ◽  
Luciferase Reporter ◽  
Core Complex ◽  
Aryl Hydrocarbon ◽  
B Virus

ABSTRACT Prior to ligand activation, the unactivated aryl hydrocarbon receptor (AhR) exists in a heterotetrameric 9S core complex consisting of the AhR ligand-binding subunit, a dimer of hsp90, and an unknown subunit. Here we report the purification of an ∼38-kDa protein (p38) from COS-1 cell cytosol that is a member of this complex by coprecipitation with a FLAG-tagged AhR. Internal amino acid sequence information was obtained, and p38 was identified as the hepatitis B virus X-associated protein 2 (XAP2). The simian ortholog of XAP2 was cloned from a COS-1 cDNA library; it codes for a 330-amino-acid protein containing regions of homology to the immunophilins FKBP12 and FKBP52. A tetratricopeptide repeat (TPR) domain in the carboxy-terminal region of XAP2 was similar to the third and fourth TPR domains of human FKBP52 and the Saccharomyces cerevisiae transcriptional modulator SSN6, respectively. Polyclonal antibodies raised against XAP2 recognized p38 in the unliganded AhR complex in COS-1 and Hepa 1c1c7 cells. It was ubiquitously expressed in murine tissues at the protein and mRNA levels. It was not required for the assembly of an AhR-hsp90 complex in vitro. Additionally, XAP2 did not directly associate with hsp90 upon in vitro translation, but was present in a 9S form when cotranslated in vitro with murine AhR. XAP2 enhanced the ability of endogenous murine and human AhR complexes to activate a dioxin-responsive element–luciferase reporter twofold, following transient expression of XAP2 in Hepa 1c1c7 and HeLa cells.

scholarly journals Increase Paclitaxel Sensitivity to Better Suppress Serous Epithelial Ovarian Cancer via Ablating Androgen Receptor/Aryl Hydrocarbon Receptor-ABCG2 Axis

Cancers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 463 ◽  
Author(s):  
Wei-Min Chung ◽  
Yen-Ping Ho ◽  
Wei-Chun Chang ◽  
Yuan-Chang Dai ◽  
Lumin Chen ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Androgen Receptor ◽  
Epithelial Ovarian Cancer ◽  
Aryl Hydrocarbon Receptor ◽  
Proximal Promoter ◽  
Luciferase Reporter ◽  
Aryl Hydrocarbon ◽  
Paclitaxel Treatment

Background: Epithelial ovarian cancer (EOC) is one of the most lethal gynecological malignancies and presents chemoresistance after chemotherapy treatment. Androgen receptor (AR) has been known to participate in proliferation. Yet the mechanisms of the resistance of this drug and its linkage to the AR remains unclear. Methods: To elucidate AR-related paclitaxel sensitivity, co-IP, luciferase reporter assay and ChIP assay were performed to identify that AR direct-regulated ABCG2 expression under paclitaxel treatment. IHC staining by AR antibody presented higher AR expression in serous-type patients than other types. AR degradation enhancer (ASC-J9) was used to examine paclitaxel-associated and paclitaxel-resistant cytotoxicity in vitro and in vivo. Results: We found AR/aryl hydrocarbon receptor (AhR)-mediates ABCG2 expression and leads to a change in paclitaxel cytotoxicity/sensitivity in EOC serous subtype cell lines. Molecular mechanism study showed that paclitaxel activated AR transactivity and bound to alternative ARE in the ABCG2 proximal promoter region. To identify AR as a potential therapeutic target, the ASC-J9 was used to re-sensitize paclitaxel-resistant EOC tumors upon paclitaxel treatment in vitro and in vivo. Conclusion: The results demonstrated that activation of AR transactivity beyond the androgen-associated biological effect. This novel AR mechanism explains that degradation of AR is the most effective therapeutic strategy for treating AR-positive EOC serous subtype.

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