scholarly journals Lipopolysaccharide-Enhanced Responses against Aryl Hydrocarbon Receptor in FcgRIIb-Deficient Macrophages, a Profound Impact of an Environmental Toxin on a Lupus-Like Mouse Model

2021 ◽  
Vol 22 (8) ◽  
pp. 4199
Author(s):  
Kanyarat Udompornpitak ◽  
Thansita Bhunyakarnjanarat ◽  
Awirut Charoensappakit ◽  
Cong Phi Dang ◽  
Wilasinee Saisorn ◽  
...  
Keyword(s):  
Aryl Hydrocarbon Receptor ◽  
Inflammatory Responses ◽  
Macrophage Polarization ◽  
Environmental Pollutants ◽  
Annexin V ◽  
Aryl Hydrocarbon ◽  
Gamma Receptor ◽  
M1 Macrophage ◽  
Environmental Toxin ◽  
Pre Treatment

Fc gamma receptor IIb (FcgRIIb) is the only inhibitory-FcgR in the FcgR family, and FcgRIIb-deficient (FcgRIIb−/−) mice develop a lupus-like condition with hyper-responsiveness against several stimulations. The activation of aryl hydrocarbon receptor (Ahr), a cellular environmental sensor, might aggravate activity of the lupus-like condition. As such, 1,4-chrysenequinone (1,4-CQ), an Ahr-activator, alone did not induce supernatant cytokines from macrophages, while the 24 h pre-treatment by lipopolysaccharide (LPS), a representative inflammatory activator, prior to 1,4-CQ activation (LPS/1,4-CQ) predominantly induced macrophage pro-inflammatory responses. Additionally, the responses from FcgRIIb−/− macrophages were more prominent than wild-type (WT) cells as determined by (i) supernatant cytokines (TNF-α, IL-6, and IL-10), (ii) expression of the inflammation associated genes (NF-κB, aryl hydrocarbon receptor, iNOS, IL-1β and activating-FcgRIV) and cell-surface CD-86 (a biomarker of M1 macrophage polarization), and (iii) cell apoptosis (Annexin V), with the lower inhibitory-FcgRIIb expression. Moreover, 8-week-administration of 1,4-CQ in 8 week old FcgRIIb−/− mice, a genetic-prone lupus-like model, enhanced lupus characteristics as indicated by anti-dsDNA, serum creatinine, proteinuria, endotoxemia, gut-leakage (FITC-dextran), and glomerular immunoglobulin deposition. In conclusion, an Ahr activation worsened the disease severity in FcgRIIb−/− mice possibly through the enhanced inflammatory responses. The deficiency of inhibitory-FcgRIIb in these mice, at least in part, prominently enhanced the pro-inflammatory responses. Our data suggest that patients with lupus might be more vulnerable to environmental pollutants.

scholarly journals A Protective Role of Aryl Hydrocarbon Receptor Repressor in Inflammation and Tumor Growth

Cancers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 589 ◽  
Author(s):  
Christoph F. A. Vogel ◽  
Yasuhiro Ishihara ◽  
Claire E. Campbell ◽  
Sarah Y. Kado ◽  
Aimy Nguyen-Chi ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Aryl Hydrocarbon Receptor ◽  
Inflammatory Responses ◽  
Environmental Pollutants ◽  
Protective Role ◽  
Potential Therapeutic Target ◽  
Embryonic Fibroblasts ◽  
Aryl Hydrocarbon ◽  
Enhancer Binding Protein

The aryl hydrocarbon receptor (AhR) is known for mediating the toxicity of environmental pollutants such as dioxins and numerous dioxin-like compounds, and is associated with the promotion of various malignancies, including lymphoma. The aryl hydrocarbon receptor repressor (AhRR), a ligand-independent, transcriptionally inactive AhR-like protein is known to repress AhR signaling through its ability to compete with the AhR for dimerization with the AhR nuclear translocator (ARNT). While AhRR effectively blocks AhR signaling, several aspects of the mechanism of AhRR’s functions are poorly understood, including suppression of inflammatory responses and its putative role as a tumor suppressor. In a transgenic mouse that overexpresses AhRR (AhRR Tg) we discovered that these mice suppress 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)- and inflammation-induced tumor growth after subcutaneous challenge of EL4 lymphoma cells. Using mouse embryonic fibroblasts (MEF) we found that AhRR overexpression suppresses the AhR-mediated anti-apoptotic response. The AhRR-mediated inhibition of apoptotic resistance was associated with a suppressed expression of interleukin (IL)-1β and cyclooxygenase (COX)-2, which was dependent on activation of protein kinase A (PKA) and the CAAT-enhancer-binding protein beta (C/EBPβ). These results provide mechanistic insights into the role of the AhRR to suppress inflammation and highlight the AhRR as a potential therapeutic target to suppress tumor growth.

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.

Targeted inhibition of CD74 attenuates adipose COX-2-MIF-mediated M1 macrophage polarization and retards obesity-related adipose tissue inflammation and insulin resistance

2018 ◽  
Vol 132 (14) ◽  
pp. 1581-1596 ◽  
Author(s):  
Pei-Chi Chan ◽  
Ting-Ni Wu ◽  
Ying-Chuan Chen ◽  
Chieh-Hua Lu ◽  
Martin Wabitsch ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Inflammatory Responses ◽  
Macrophage Polarization ◽  
Mrna Levels ◽  
Model Assessment ◽  
M1 Macrophage ◽  
Cox 2 ◽  
Highly Correlated ◽  
Targeted Inhibition

Adipose tissue (AT) inflammation is crucial to the development of obesity-associated insulin resistance. Our aim was to investigate the contribution of cyclooxygenase-2 (COX-2)/macrophage migration inhibitory factor (MIF)-mediated cross-talk between hypertrophic adipocytes and macrophages to the etiology of AT inflammation and the involvement of CD74 using human SGBS adipocytes, THP-1 macrophages and mice fed a high-fat (HF) diet. The MIF and CD74 mRNA levels in the adipocytes and stromal vascular cells (SVCs) of white fat were highly correlated with body weight (BW), homeostatic model assessment for insulin resistance (HOMA-IR), and adipose macrophage marker expression levels, especially those in SVCs. COX-2 inhibition suppressed the elevation of MIF production in HF white adipocytes as well as palmitate and hypoxic-treated SGBS adipocytes. Treatment of adipocytes transfected with shCOX-2 and siMIF or subjected to MIF depletion in the medium reversed the pro-inflammatory responses in co-incubated THP-1 cells. Inhibition of NF-κB activation reversed the COX2-dependent MIF secretion from treated adipocytes. The targeted inhibition of macrophage CD74 prevented M1 macrophage polarization in the above co-culture model. The COX-2-dependent increases in CD74 gene expression and MIF release in M1-polarized macrophages facilitated the expression of COX-2 and MIF in co-cultured SGBS adipocytes. CD74 shRNA intravenous injection suppressed HF-induced AT M1 macrophage polarization and inflammation as well as insulin resistance in mice. The present study suggested that COX-2-mediated MIF secretion through NF-κB activation from hypertrophic and hypoxic adipocytes as well as M1 macrophages might substantially contribute to the phenotypic switch of AT macrophages through CD74 in obesity. Inhibition of CD74 could attenuate AT inflammation and insulin resistance in the development of HF diet-induced obesity.

scholarly journals Activation of aryl hydrocarbon receptor (AhR) in mesenchymal stem cells modulates macrophage polarization in asthma

2020 ◽  
Vol 17 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Zhuang Cui ◽  
Yuan Feng ◽  
Danqing Li ◽  
Taoping Li ◽  
Peisong Gao ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Aryl Hydrocarbon Receptor ◽  
Macrophage Polarization ◽  
Aryl Hydrocarbon

scholarly journals The Role of the Aryl Hydrocarbon Receptor (AHR) in Immune and Inflammatory Diseases

2018 ◽  
Vol 19 (12) ◽  
pp. 3851 ◽  
Author(s):  
Drew Neavin ◽  
Duan Liu ◽  
Balmiki Ray ◽  
Richard Weinshilboum
Keyword(s):  
Aryl Hydrocarbon Receptor ◽  
Nuclear Receptor ◽  
Binding Sites ◽  
Inflammatory Responses ◽  
Inflammatory Diseases ◽  
Dependent Manner ◽  
Nucleotide Polymorphisms ◽  
Aryl Hydrocarbon ◽  
Inflammatory Processes ◽  
Targeted Gene Expression

The aryl hydrocarbon receptor (AHR) is a nuclear receptor that modulates the response to environmental stimuli. It was recognized historically for its role in toxicology but, in recent decades, it has been increasingly recognized as an important modulator of disease—especially for its role in modulating immune and inflammatory responses. AHR has been implicated in many diseases that are driven by immune/inflammatory processes, including major depressive disorder, multiple sclerosis, rheumatoid arthritis, asthma, and allergic responses, among others. The mechanisms by which AHR has been suggested to impact immune/inflammatory diseases include targeted gene expression and altered immune differentiation. It has been suggested that single nucleotide polymorphisms (SNPs) that are near AHR-regulated genes may contribute to AHR-dependent disease mechanisms/pathways. Further, we have found that SNPs that are outside of nuclear receptor binding sites (i.e., outside of AHR response elements (AHREs)) may contribute to AHR-dependent gene regulation in a SNP- and ligand-dependent manner. This review will discuss the evidence and mechanisms of AHR contributions to immune/inflammatory diseases and will consider the possibility that SNPs that are outside of AHR binding sites might contribute to AHR ligand-dependent inter-individual variation in disease pathophysiology and response to pharmacotherapeutics.

The effect of benzo[α]pyrene on expression and signaling cross talk of aryl hydrocarbon receptor and NFATc1 in mouse lung tissue

2014 ◽  
Vol 32 (7) ◽  
pp. 1246-1253 ◽  
Author(s):  
Maliheh Parsa ◽  
Seyed Nasser Ostad ◽  
Seyed Mohammad Hossein Noori Moogahi ◽  
Mohammad Bayat ◽  
Mohammad Hossein Ghahremani
Keyword(s):  
Aryl Hydrocarbon Receptor ◽  
Lung Tissue ◽  
Cross Talk ◽  
Environmental Pollutants ◽  
Lung Damage ◽  
Mouse Lung ◽  
Aryl Hydrocarbon ◽  
Embedded Blocks ◽  
Mouse Lung Tissue ◽  
Imagej Software

Objective: Polycyclic aromatic hydrocarbons (PAHs) are potent environmental pollutants. Benzo[α]pyrene (B[α]P) is the major compound of PAHs that acts by activating aryl hydrocarbon receptor (AhR) in cells. B[α]P is a known carcinogen and an immunotoxicant; however, its role with regard to nuclear factor of activated T cell (NFAT) pathway is unclear. AhR and NFAT signaling pathways have common roles in pathological functions in immunotoxicity and lung cancer. In this study, the effect of AhR activation on expression and signaling cross talk of AhR and NFATc1 pathways in mouse lung tissue has been investigated. Methods: Swiss albino mice were randomly allocated to five groups and administered with cyclosporin A (CsA) and B[α]P for seven constitutive days. Animals were then killed, and lung tissues were obtained after washing the whole blood. Paraffin-embedded blocks were prepared, and 5 µm sections were cut for histopathological and immunohistochemical assessments. The results were scored by observer and digitally analyzed using ImageJ software. Results: Our data showed that CsA administration resulted in a significant reduction of AhR expression. This effect was partly blocked in mice coadministrated with B[α]P and CsA. NFATc1 expression was also reduced in CsA-treated animals. Furthermore, CsA inhibited the pathological effects of B[α]P in mouse lung tissue. Conclusion: AhR expression is dependent on NFATc1 activation, and NFATc1 inhibition remarkably decreases AhR expression. However, it seems that total expression of NFATc1 is not dependent on AhR expression or activation. Moreover, CsA can prevent B[α]P-induced lung tissue damage, and it remarkably decreases NFATc1 expression. The results from this study point toward the molecular interactions of AhR and NFATc1 activation in lung tissue and the benefit of CsA treatment in B[α]P-induced lung damage.

Activation of the aryl hydrocarbon receptor increases pulmonary neutrophilia and diminishes host resistance to influenza A virus

2005 ◽  
Vol 289 (1) ◽  
pp. L111-L124 ◽  
Author(s):  
Sabine Teske ◽  
Andrea A. Bohn ◽  
Jean F. Regal ◽  
Joshua J. Neumiller ◽  
B. Paige Lawrence
Keyword(s):  
Aryl Hydrocarbon Receptor ◽  
Influenza A Virus ◽  
Influenza A ◽  
Viral Infections ◽  
Inflammatory Responses ◽  
Neutrophil Function ◽  
Aryl Hydrocarbon ◽  
Potent Agonist

Unlike their role in bacterial infection, less is known about the role of neutrophils during pulmonary viral infection. Exposure to pollutant 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD, dioxin) results in excess neutrophils in the lungs of mice infected with influenza A virus. TCDD is the most potent agonist for the aryl hydrocarbon receptor (AhR), and exposure to AhR ligands has been correlated with exacerbated inflammatory lung diseases. However, knowledge of the effects of AhR agonists on neutrophils is limited. Likewise, the factors regulating neutrophil responses during respiratory viral infections are not well characterized. To address these knowledge gaps, we determined the in vivo levels of KC, MIP-1α, MIP-2, LIX, IL-6, and C5a in infected mouse lungs. Our data show that these neutrophil chemoattractants are generally produced transiently in the lung within 12–24 h of infection. We also report that expression of CD11a, CD11b, CD49d, CD31, and CD38 is increased on pulmonary neutrophils in response to influenza virus. Using AhR-deficient mice, we demonstrate that excess neutrophilia in the lung is mediated by activation of the AhR and that this enhanced neutrophilia correlates directly with decreased survival in TCDD-exposed mice. Although AhR activation results in more neutrophils in the lungs, we show that this is not mediated by deregulation in levels of common neutrophil chemoattractants, expression of adhesion molecules on pulmonary neutrophils, or delayed death of neutrophils. Likewise, exposure to TCDD did not enhance pulmonary neutrophil function. This study provides an important first step in elucidating the mechanisms by which AhR agonists exacerbate pulmonary inflammatory responses.

scholarly journals Organ-specific effects on glycolysis by the dioxin-activated aryl hydrocarbon receptor

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243842
Author(s):  
Silvia Diani-Moore ◽  
Tiago Marques Pedro ◽  
Arleen B. Rifkind
Keyword(s):  
Chick Embryo ◽  
Aryl Hydrocarbon Receptor ◽  
Environmental Pollutants ◽  
Glucose Transporters ◽  
Metabolic Effects ◽  
Mrna Levels ◽  
Aryl Hydrocarbon ◽  
Phosphorylated Akt ◽  
Thymus Atrophy ◽  
Human Primary Hepatocytes

Activation of the aryl hydrocarbon receptor (AHR) by the environmental toxin dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD) causes diverse toxicities, including thymus atrophy and hepatosteatosis. The mechanisms by which AHR activation by TCDD leads to these toxicities are not fully understood. Here we studied the effects of TCDD on a major energy pathway, glycolysis, using the chick embryo close to hatching, a well-established model for studying dioxin toxicity. We showed that 24 hr of TCDD treatment causes changes in glycolysis in both thymus and liver. In thymus glands, TCDD decreased mRNAs for glycolytic genes and glucose transporters, glycolytic indices and levels of IL7 mRNA, phosphorylated AKT (pAKT) and HIF1A, stimulators of glycolysis and promoters of survival and proliferation of thymic lymphocytes. In contrast, in liver, TCDD increased mRNA levels for glycolytic genes and glucose transporters, glycolytic endpoints and pAKT levels. Similarly, increases by TCDD in mRNA levels for glycolytic genes and glucose transporters in human primary hepatocytes showed that effects in chick embryo liver pertain also to human cells. Treatment with the glycolytic inhibitor 2-deoxy-d-glucose exacerbated the effects on thymus atrophy by TCDD, supporting a role for decreased glycolysis in thymus atrophy by TCDD, but did not prevent hepatosteatosis. NAD+ precursors abolished TCDD effects on glycolytic endpoints in both thymus and liver. In summary, we report here that dioxin disrupts glycolysis mediated energy metabolism in both thymus and liver, and that it does so in opposite ways, decreasing it in the thymus and increasing it in the liver. Further, the findings support NAD+ boosting as a strategy against metabolic effects of environmental pollutants such as dioxins.

scholarly journals AR Deficiency Inhibits LPS-induced M1 Response in Macrophages by Activating Autophagy

2020 ◽  
Author(s):  
Peng Cheng ◽  
Jianwei Xie ◽  
Zhiyong Liu ◽  
Jian Wang
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Inflammatory Responses ◽  
Macrophage Polarization ◽  
Critical Role ◽  
Transcriptional Level ◽  
Mrna Levels ◽  
M1 Polarization ◽  
M1 Macrophage ◽  
Oxide Synthase

Abstract Macrophage M1 polarization mediates inflammatory responses and tissue damage. Recently, aldose reductase (AR) has been shown to play a critical role in of M1 polarization in macrophages. However, the underlying mechanisms are unknown. Here, we demonstrated, for the first time, that AR deficiency repressed the induction of inducible nitric oxide synthase in lipopolysaccharide (LPS)-stimulated macrophages via activation of autophagy. This suppression was related to a defect in the inhibitor of nuclear factor κB (NF-κB) kinase (IKK) complex in the classical NF-κB pathway. However, the mRNA levels of the IKKβ and IKKγ were not reduced in LPS-treated AR knockout (KO) macrophages, indicating that their proteins were downregulated at the post-transcriptional level. We discovered that LPS stimuli induced the recruitment of more beclin1 and increased autophagosome formation in AR-deficient macrophages. Blocking autophagy by 3-methyladenine and ammonium chloride treatment restored IKKβ and IKKγ protein levels and increased nitric oxide synthase production in LPS-stimulated AR-deficient macrophages. More assembled IKKβ and IKKγ undergo ubiquitination and recruit the autophagic adaptor p62 in LPS-induced AR KO macrophages, promoting their delivery to autophagosomes and lysosomes. Collectively, these findings suggest that AR deficiency involves in the regulation of NF-κB signaling, and extends the role of selective autophagy in fine-tuned M1 macrophage polarization.

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