scholarly journals Trajectory Shifts in Interdisciplinary Research of the Aryl Hydrocarbon Receptor—A Personal Perspective on Thymus and Skin

2021 ◽  
Vol 22 (4) ◽  
pp. 1844
Author(s):  
Charlotte Esser
Keyword(s):  
Transcription Factor ◽  
Immune System ◽  
Environmental Pollution ◽  
Aryl Hydrocarbon Receptor ◽  
Interdisciplinary Research ◽  
Adaptive Response ◽  
Personal Perspective ◽  
Aryl Hydrocarbon

Identifying historical trajectories is a useful exercise in research, as it helps clarify important, perhaps even “paradigmatic”, shifts in thinking and moving forward in science. In this review, the development of research regarding the role of the transcription factor “aryl hydrocarbon receptor” (AHR) as a mediator of the toxicity of environmental pollution towards a link between the environment and a healthy adaptive response of the immune system and the skin is discussed. From this fascinating development, the opportunities for targeting the AHR in the therapy of many diseases become clear.

scholarly journals Immunotoxicity of Xenobiotics in Fish: A Role for the Aryl Hydrocarbon Receptor (AhR)?

2021 ◽  
Vol 22 (17) ◽  
pp. 9460
Author(s):  
Helmut Segner ◽  
Christyn Bailey ◽  
Carolina Tafalla ◽  
Jun Bo
Keyword(s):  
Immune System ◽  
Aryl Hydrocarbon Receptor ◽  
Disease Susceptibility ◽  
Immune Cell ◽  
Physiological Role ◽  
Immune Gene ◽  
Immune Systems ◽  
Aryl Hydrocarbon ◽  
The Impact

The impact of anthropogenic contaminants on the immune system of fishes is an issue of growing concern. An important xenobiotic receptor that mediates effects of chemicals, such as halogenated aromatic hydrocarbons (HAHs) and polyaromatic hydrocarbons (PAHs), is the aryl hydrocarbon receptor (AhR). Fish toxicological research has focused on the role of this receptor in xenobiotic biotransformation as well as in causing developmental, cardiac, and reproductive toxicity. However, biomedical research has unraveled an important physiological role of the AhR in the immune system, what suggests that this receptor could be involved in immunotoxic effects of environmental contaminants. The aims of the present review are to critically discuss the available knowledge on (i) the expression and possible function of the AhR in the immune systems of teleost fishes; and (ii) the impact of AhR-activating xenobiotics on the immune systems of fish at the levels of immune gene expression, immune cell proliferation and immune cell function, immune pathology, and resistance to infectious disease. The existing information indicates that the AhR is expressed in the fish immune system, but currently, we have little understanding of its physiological role. Exposure to AhR-activating contaminants results in the modulation of numerous immune structural and functional parameters of fish. Despite the diversity of fish species studied and the experimental conditions investigated, the published findings rather uniformly point to immunosuppressive actions of xenobiotic AhR ligands in fish. These effects are often associated with increased disease susceptibility. The fact that fish populations from HAH- and PAH-contaminated environments suffer immune disturbances and elevated disease susceptibility highlights that the immunotoxic effects of AhR-activating xenobiotics bear environmental relevance.

scholarly journals Toward Understanding the Role of Aryl Hydrocarbon Receptor in the Immune System: Current Progress and Future Trends

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Hamza Hanieh
Keyword(s):  
Immune System ◽  
Aryl Hydrocarbon Receptor ◽  
Immune Cells ◽  
Immune Cell ◽  
Current Knowledge ◽  
Physiological Role ◽  
Clinical Practices ◽  
Aryl Hydrocarbon ◽  
Active Research

The immune system is regulated by distinct signaling pathways that control the development and function of the immune cells. Accumulating evidence suggest that ligation of aryl hydrocarbon receptor (Ahr), an environmentally responsive transcription factor, results in multiple cross talks that are capable of modulating these pathways and their downstream responsive genes. Most of the immune cells respond to such modulation, and many inflammatory response-related genes contain multiple xenobiotic-responsive elements (XREs) boxes upstream. Active research efforts have investigated the physiological role of Ahr in inflammation and autoimmunity using different animal models. Recently formed paradigm has shown that activation of Ahr by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or 3,3′-diindolylmethane (DIM) prompts the differentiation of CD4+Foxp3+regulatory T cells (Tregs) and inhibits T helper (Th)-17 suggesting that Ahr is an innovative therapeutic strategy for autoimmune inflammation. These promising findings generate a basis for future clinical practices in humans. This review addresses the current knowledge on the role of Ahr in different immune cell compartments, with a particular focus on inflammation and autoimmunity.

scholarly journals Concentration and Duration of Indoxyl Sulfate Exposure Affects Osteoclastogenesis by Regulating NFATc1 via Aryl Hydrocarbon Receptor

2020 ◽  
Vol 21 (10) ◽  
pp. 3486 ◽  
Author(s):  
Wen-Chih Liu ◽  
Jia-Fwu Shyu ◽  
Paik Seong Lim ◽  
Te-Chao Fang ◽  
Chien-Lin Lu ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Aryl Hydrocarbon Receptor ◽  
Critical Role ◽  
Osteoclast Differentiation ◽  
Indoxyl Sulfate ◽  
Raw 264.7 Cells ◽  
High Dose ◽  
Activated T Cells ◽  
Aryl Hydrocarbon

Indoxyl sulfate (IS) is a chronic kidney disease (CKD)-specific renal osteodystrophy metabolite that affects the nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), a transcription factor promoting osteoclastogenesis. However, the mechanisms underlying the regulation of NFATc1 by IS remain unknown. It is intriguing that the Aryl hydrocarbon receptor (AhR) plays a key role in osteoclastogenesis, since IS is an endogenous AhR agonist. This study investigates the relationship between IS concentration and osteoclast differentiation in Raw 264.7 cells, and examines the effects of different IS concentrations on NFATc1 expression through AhR signaling. Our data suggest that both osteoclastogenesis and NFATc1 are affected by IS through AhR signaling in both dose- and time-dependent manners. Osteoclast differentiation increases with short-term, low-dose IS exposure and decreases with long-term, high-dose IS exposure. Different IS levels switch the role of AhR from that of a ligand-activated transcription factor to that of an E3 ubiquitin ligase. We found that the AhR nuclear translocator may play an important role in the regulation of these dual functions of AhR under IS treatment. Altogether, this study demonstrates that the IS/AhR/NFATc1 signaling axis plays a critical role in osteoclastogenesis, indicating a potential role of AhR in the pathology and abnormality of bone turnover in CKD patients.

scholarly journals The Aryl Hydrocarbon Receptor Relays Metabolic Signals to Promote Cellular Regeneration

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Fanny L. Casado
Keyword(s):  
Stem Cells ◽  
Cell Death ◽  
Transcription Factor ◽  
Regenerative Medicine ◽  
Aryl Hydrocarbon Receptor ◽  
Signaling Pathways ◽  
Metabolic Efficiency ◽  
Aryl Hydrocarbon ◽  
Cellular Regeneration

While sensing the cell environment, the aryl hydrocarbon receptor (AHR) interacts with different pathways involved in cellular homeostasis. This review summarizes evidence suggesting that cellular regeneration in the context of aging and diseases can be modulated by AHR signaling on stem cells. New insights connect orphaned observations into AHR interactions with critical signaling pathways such as WNT to propose a role of this ligand-activated transcription factor in the modulation of cellular regeneration by altering pathways that nurture cellular expansion such as changes in the metabolic efficiency rather than by directly altering cell cycling, proliferation, or cell death. Targeting the AHR to promote regeneration might prove to be a useful strategy to avoid unbalanced disruptions of homeostasis that may promote disease and also provide biological rationale for potential regenerative medicine approaches.

scholarly journals Gut SymbiontsLactobacillus reuteriR2lc and 2010 Encode a Polyketide Synthase Cluster That Activates the Mammalian Aryl Hydrocarbon Receptor

2018 ◽  
Vol 85 (10) ◽  
Author(s):  
Mustafa Özçam ◽  
Restituto Tocmo ◽  
Jee-Hwan Oh ◽  
Amin Afrazi ◽  
Joshua D. Mezrich ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Immune System ◽  
Aryl Hydrocarbon Receptor ◽  
Gene Cluster ◽  
Polyketide Synthase ◽  
Lactobacillus Reuteri ◽  
Intestinal Inflammation ◽  
Host Immune System ◽  
Content Type ◽  
Aryl Hydrocarbon

ABSTRACTA mechanistic understanding of microbe-host interactions is critical to developing therapeutic strategies for targeted modulation of the host immune system. Different members of the gut symbiont speciesLactobacillus reuterimodulate host health by, for example, reduction of intestinal inflammation. Previously, it was shown thatL. reuteriactivates the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that plays an important role in the mucosal immune system, by the production of tryptophan catabolites. Here, we identified a novel pathway by whichL. reuteriactivates AhR, which is independent of tryptophan metabolism. We screened a library of 36 L. reuteristrains and determined that R2lc and 2010, strains with a pigmented phenotype, are potent AhR activators. By whole-genome sequencing and comparative genomics, we identified genes unique to R2lc and 2010. Our analyses demonstrated that R2lc harbors two genetically distinct polyketide synthase (PKS) clusters, functionally unknown (fun) andpks, each carried by a multicopy plasmid. Inactivation ofpks, but notfun, abolished the ability of R2lc to activate AhR.L. reuteri2010 has a gene cluster homologous to thepkscluster in R2lc with an identical gene organization, which is also responsible for AhR activation. In conclusion, we identified a novel PKS pathway inL. reuteriR2lc and 2010 that is responsible for AhR activation.IMPORTANCETemporary changes in the composition of the microbiota, for example, by oral administration of probiotics, can modulate the host immune system. However, the underlying mechanisms by which probiotics interact with the host are often unknown. Here, we show thatLactobacillus reuteriR2lc and 2010 harbor an orthologous PKS gene cluster that activates the aryl hydrocarbon receptor (AhR). AhR is a ligand-activated transcription factor that plays a key role in a variety of diseases, including amelioration of intestinal inflammation. Understanding the mechanism by which a bacterium modulates the immune system is critical for applying rational selection strategies for probiotic supplementation. Finally, heterologous and/or optimized expression of PKS is a logical next step toward the development of next-generation probiotics to prevent and treat disease.

scholarly journals The aryl hydrocarbon receptor and the gut–brain axis

2021 ◽  
Author(s):  
Andreia Barroso ◽  
João Vitor Mahler ◽  
Pedro Henrique Fonseca-Castro ◽  
Francisco J. Quintana
Keyword(s):  
Transcription Factor ◽  
Aryl Hydrocarbon Receptor ◽  
Therapeutic Target ◽  
Potential Value ◽  
Aryl Hydrocarbon ◽  
Immune Mediated ◽  
Health And Disease

AbstractThe aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor initially identified as the receptor for dioxin. Almost half a century after its discovery, AHR is now recognized as a receptor for multiple physiological ligands, with important roles in health and disease. In this review, we discuss the role of AHR in the gut–brain axis and its potential value as a therapeutic target for immune-mediated diseases.

Molecular interactions of the aryl hydrocarbon receptor and its biological and toxicological relevance for reproduction

Reproduction ◽  
2005 ◽  
Vol 129 (4) ◽  
pp. 379-389 ◽  
Author(s):  
P Pocar ◽  
B Fischer ◽  
T Klonisch ◽  
S Hombach-Klonisch
Keyword(s):  
Transcription Factor ◽  
Aryl Hydrocarbon Receptor ◽  
Reproductive Tract ◽  
Wide Spectrum ◽  
Environmental Pollutants ◽  
Large Body ◽  
Female Reproductive Tract ◽  
Female Reproduction ◽  
Aryl Hydrocarbon

The dioxin/aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor responsive to both natural and man-made environmental compounds. AhR and its nuclear partner ARNT are expressed in the female reproductive tract in a variety of species and several indications suggest that the AhR might play a pivotal role in the physiology of reproduction. Furthermore, it appears to be the mediator of most, if not all, the adverse effects on reproduction of a group of highly potent environmental pollutants collectively called aryl hydrocarbons (AHs), including the highly toxic compound 2,3,7,8-tetrachlor-odibenzo-p-dioxin (TCDD). Although a large body of recent literature has implicated AhR in multiple signal transduction pathways, the mechanisms of action resulting in a wide spectrum of effects on female reproduction are largely unknown. Here we summarize the major types of molecular cross-talks that have been identified for the AhR and linked cell signaling pathways and that are relevant for the understanding of the role of this transcription factor in female reproduction.

scholarly journals Aryl Hydrocarbon Receptor Connects Inflammation to Breast Cancer

2020 ◽  
Vol 21 (15) ◽  
pp. 5264 ◽  
Author(s):  
Tiziana Guarnieri
Keyword(s):  
Breast Cancer ◽  
Transcription Factor ◽  
Immune System ◽  
Aryl Hydrocarbon Receptor ◽  
Inflammatory Marker ◽  
Eukaryotic Cells ◽  
Breast Carcinogenesis ◽  
Constitutive Activation ◽  
Aryl Hydrocarbon ◽  
Over Time

Aryl hydrocarbon receptor (AhR), an evolutionary conserved transcription factor, is a pleiotropic signal transductor. Thanks to its promiscuous ligand binding domain, during the evolution of eukaryotic cells its developmental functions were integrated with biosensor functions. Its activation by a multitude of endogenous and exogenous molecules stimulates its participation in several pathways, some of which are linked to inflammation and breast cancer (BC). Over time, the study of this malignancy has led to the identification of several therapeutic targets in cancer cells. An intense area of study is dedicated to BC phenotypes lacking adequate targets. In this context, due to its high constitutive activation in BC, AhR is currently gaining more and more attention. In this review, I have considered its interactions with: 1. the immune system, whose dysregulation is a renowned cancer hallmark; 2. interleukin 6 (IL6) which is a pivotal inflammatory marker and is closely correlated to breast cancer risk; 3. NF-kB, another evolutionary conserved transcription factor, which plays a key role in immunoregulatory functions, inflammatory response and breast carcinogenesis; 4. kynurenine, a tryptophan-derived ligand that activates and bridges AhR to chronic inflammation and breast carcinogenesis. Overall, the data here presented form an interesting framework where AhR is an interesting connector between inflammation and BC.

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