Differential Effect of ITE on the Aryl Hydrocarbon Receptor Signaling in Breast Cancer Tissue: A Histopathological Study / Efecto Diferencial de ITE en la Señalización del Receptor de Hidrocarburo de Arilo en Tejido de Cáncer de Mama: Un Estudio Histopatológico

SUMMARY: Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that is highly expressed in various types of cancers including breast cancer. However, the role of AhR with its endogenous ligand 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) on the progression of breast cancer remains poorly understood. We aimed to investigate cell proliferation and migration states in breast cancer after activating AhR with the endogenous ligand ITE. Breast cancer tissue was evaluated by cell lines, immunohistochemistry, reverse transcription-polymerase chain reaction, cell proliferation, flow cytometry, migration assays and western blot techniques. We found that AhR was widely expressed in breast cancer tissues and metastasis lymph node tissues, but not in normal tissues. The expression AhR was independent between the age, grades and TNM classifications for breast cancer tissues. ITE treatment significantly induced the activation of AhR in a time-dependent manner in both MCF-7 and T47D breast cancer cell lines. Meanwhile, ITE did not affect the cell migration but significantly suppressed the cell proliferation in estrogen receptor positive (ER+) MCF-7 andT47D cells, which probably attribute to the induction of cell cycle arrest in G1 phase and shortened S phase. Further mechanism study showed that ERK1/2 and AKT signaling were required for the activation of AhR in MCF-7 cells. These data suggest that AhR is a potential new target for treating patients with breast cancer. ITE may be more potentially used for therapeutic intervention for breast cancer with the kind of ER(+).

El receptor de hidrocarburo de arilo (AhR) es un factor de transcripción activado por ligando que se expresa en gran medida en varios tipos de cáncer, incluido el cáncer de mama. Sin embargo, el papel de AhR con su ligando endógeno 2- (1'H-indol-3'-carbonil)-tiazol-4-ácido carboxílico metil éster (ITE) en la progresión del cáncer de mama sigue siendo poco conocido. Nuestro objetivo fue investigar la proliferación celular y los estados de migración en el cáncer de mama después de activar AhR con el ligando endógeno ITE. El tejido de cáncer de mama se evaluó mediante líneas celulares, inmunohistoquímica, reacción en cadena de la polimerasa con transcriptasa inversa, proliferación celular, citometría de flujo, ensayos de migración y técnicas de transferencia Western. Descubrimos que AhR se expresó ampliamente en tejidos de cáncer de mama y en linfonodos con metástasis, pero no en tejidos normales. La expresión AhR fue independiente entre la edad, grados y clasificaciones TNM para tejidos de cáncer de mama. El tratamiento con ITE indujo significativamente la activación de AhR de manera dependiente del tiempo en las líneas celulares de cancer de mama MCF-7 y T47D. Mientras tanto, ITE no afectó la migración celular, pero suprimió significativamente la proliferación celular en células MCF-7 y T47D con receptor de estrógeno positivo (ER+), lo que probablemente se atribuye a la inducción de la detención del ciclo celular en la fase G1 y la fase S acortada. Un estudio adicional del mecanismo mostró que las señales de ERK1/2 y AKT eran necesarias para la activación de AhR en las células MCF-7. Estos datos sugieren que AhR es un nuevo objetivo potencial para el tratamiento de pacientes con cáncer de mama. ITE puede ser utilizado más potencialmente en la intervención terapéutica para el cáncer de mama con el tipo de ER (+).

Risk factors and their warning value for the occurrence of sepsis in patients with severe multiple trauma / 中华创伤杂志

Objective:To investigate the risk factors and their warning value for the occurrence of sepsis in patients with severe multiple trauma.Methods:A retrospective cohort study was conducted to analyze the clinical data of 92 patients with severe multiple trauma admitted to Yuyao People′s Hospital from July 2019 to October 2021. There were 71 males and 21 females, with the age range of 36-55 years [(45.5±13.6)years]. The injury severity score (ISS) was 20-29 points [(25.3±6.4)points]. The patients were divided into sepsis group ( n=32) and non-sepsis group ( n=60) according to whether sepsis occurred during hospitalization. Data were recorded for the two groups, including gender, age, basic diseases, cause of injury, number of injury sites, ISS, post-injury complications, and levels of aryl hydrocarbon receptor (AHR), C-reactive protein (CRP) and procalcitonin (PCT) at 1, 3 and 5 days after injury. The above data were analyzed to identify their correlation with the occurrence of sepsis in patients with severe multiple trauma by univariate analysis. The independent risk factors for sepsis in patients with severe multiple trauma were determined by multivariate Logistic regression analysis. The warning value of the single or combined risk factors for the occurrence of sepsis in patients with severe multiple trauma was evaluated by the receiver operating characteristic (ROC) curve and area under the curve (AUC). Results:By univariate analysis, it was demonstrated that the occurrence of sepsis was correlated with ISS, level of AHR at day 1 after injury, level of CRP at day 3 after injury and level of PCT at day 3 after injury ( P<0.05 or 0.01), but not with age, sex, basic diseases, level of AHR at 3, 5 days after injury, level of PCT at 1, 5 days after injury and level of CRP at 1, 5 days after injury (all P>0.05). By multivariate Logistic regression analysis, higher ISS ( OR=1.12, 95% CI 1.01, 1.24, P<0.05), level of AHR at day 1 after injury ( OR=1.30, 95% CI 1.10, 1.52, P<0.01) and level of PCT at day 3 after injury ( OR=1.81, 95% CI 1.08, 3.03, P<0.05) were found to be strongly correlated with the occurrence of sepsis. ROC curve analysis showed that higher ISS (AUC=0.69, 95% CI 0.57, 0.76) and level of AHR at day 1 after injury (AUC=0.79, 95% CI 0.68, 0.90) had warning value for the occurrence of sepsis, and the warning efficiency of combined panel was much better (AUC=0.86, 95% CI 0.77, 0.95). Conclusions:Higher ISS, level of AHR at day 1 after injury and level of PCT at day 3 after injury are independent risk factors for the occurrence of sepsis in patients with severe multiple trauma. ISS, AHR and combination of both exhibit good warning value for the occurrence of sepsis in patients with severe multiple trauma.

Roles of aryl hydrocarbon receptors in diesel exhaust inhalation-induced cardiopulmonary toxicities during initiation of pulmonary respiration in chicken / 环境与职业医学

Background Due to the limited availability of established research models, very few studies addressed the health effects and underlying mechanisms following exposure to diesel exhaust during the initiation of pulmonary respiration. It is highly demanded to elucidate such health effects and underlying mechanisms, so as to exert protective measures during the early stages of life. Objective To evaluate the health effects of diesel exhaust very-early-in-life inhalation in hatchling chicken with a novel chicken embryo air cell inhalation exposure model, and to explore the potential roles of aryl hydrocarbon receptor signaling pathways in the observed effects with a specific aryl hydrocarbon receptor inhibitor. Methods Fertilized chicken eggs were assigned into five groups randomly (15 eggs per group): control group, air control group, aryl hydrocarbon receptor inhibitor (PDM2) group, diesel exhaust group, and diesel exhaust + aryl hydrocarbon receptor inhibitor (PDM2) group. Fertilized eggs were incubated with standard procedure. At embryonic day 17 (ED17), aryl hydrocarbon receptor inhibitor was administered to the corresponding animals. During embryonic day 18-19 (ED18-19), chicken embryos were exposed to diesel exhaust via air cell inhalation, then placed back to incubator until hatch. The air control group received clean air infusion during ED18-19, while the control group did not receive any treatment. Within 24 h post-hatch, 26 hatchling chickens were anesthetized with sodium pentobarbital, subjected to electrocardiography, and sacrificed to harvest tissue samples of heart and lung. Cardiopulmonary toxicities were evaluated by histopathology, and potential changes in the protein expression levels of aryl hydrocarbon receptor pathway molecule cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) and fibrosis-related pathway molecule phosphorylated SMAD family member 2 (pSMAD2) were assessed by Western blotting. The remaining 29 hatchling chickens were reared until two weeks old, and then subjected to identical treatments. Results The inhalation exposure to diesel exhaust at initiation of pulmonary respiration resulted in thickened right ventricular wall (by 220.3% relative to the control group, same hereafter) and elevated heart rate (17.4%) in one-day-old hatchling chickens. Although no remarkable fibrotic lesions were observed at this point, the expression levels of CYP1A1 and phosphorylation levels of SMAD2 in the lung tissues significantly increased (by 81.3% and 71.6%, respectively). Such changes were effectively abolished by the aryl hydrocarbon receptor inhibitor PDM2 pretreatment. In the two-week-old animals, the thickened right ventricular wall (by 339.3%) and elevated heart rate (by 18.9%) persisted, and significant fibrotic lesions were observed in the lung tissue samples under Masson staining. Again, the aryl hydrocarbon receptor inhibitor PDM2 pretreatment effectively abolished such changes. In addition, no statistically significant changes in CYP1A1 expression levels were observed in the two-week-old chicken lung samples, and a remarkable down-regulation of SMAD2 phosphorylation was observed. The aryl hydrocarbon receptor inhibitor PDM2 pretreatment independently decreased the phosphorylation levels of SMAD2 in the two-week-old chicken lung samples. Conclusion Inhalation exposure to diesel exhaust at initiation of pulmonary respiration could result in persistent cardiopulmonary injury in hatchling chickens, and the underlying mechanism might be associated with the regulation of pSMAD2 by the aryl hydrocarbon receptor signaling pathway.

Tapinarof: A Felicitous Discovery in Psoriasis Treatment

Tapinarof is a novel topical formulation approved recently, in May 2022, by the United States Food and Drug Administration to treat plaque psoriasis. Existing topical therapies for psoriasis are limited by systemic and local adverse effects, medication cost and repeated administration, thus significantly hampering the compliance of patients to therapy. These limitations can be resolved by tapinarof owing to its better efficacy and favourable safety profile in psoriasis management. Tapinarof was developed with a unique mechanism targeting the aryl hydrocarbon receptor (AhR) involved in inflammation and modulation of skin barrier integrity in inflammatory dermatological disorders such as psoriasis and atopic dermatitis. The efficacy and safety outcomes of tapinarof in psoriasis were justified through the two pivotal clinical trials, namely, PSOARING 1 and PSOARING 2. The common adverse effects observed with tapinarof are folliculitis, contact dermatitis and headache. The literature search was conducted for efficacy and safety of tapinarof in the electronic databases of PubMed and Cochrane using a combination of keywords such as tapinarof, psoriasis and AhR. This review will delineate the molecular mechanisms underlying the action of tapinarof and also summarise the trial data supporting the claim that tapinarof is replacing the existing standard of care in psoriasis management.

Every-other-day fasting attenuated inflammation in rats after spinal cord injury via the aryl hydrocarbon receptor/suppressor of cytokine signaling 2/nuclear transcription factor-κB signaling pathway / 中国康复理论与实践

ObjectiveTo explore the role of aryl hydrocarbon receptor/suppressor of cytokine signaling 2/nuclear transcription factor-κB (AHR/SOCS2/NF-κB) signaling in the reduction of spinal cord injury (SCI) inflammation with every-other-day fasting (EODF). MethodsA total of 36 healthy male Sprague-Dawley rats were randomly divided into sham group (n = 12), model group (n = 12) and EODF group (n = 12). The latter two groups were established C5 spinal cord hemi-clamp model. The EODF group received EODF, namely fasting and feeding per 24 hours (water free), for two weeks after operation. They were assessed with Grooming Test before operation, and one, seven and 14 days after operationt, respectively. Pathological injury of spinal cord was observed with HE staining 14 days after operation, while the expression of AHR, SOCS2 and NF-κB proteins were detected with Western blotting, and the mRNA of AHR, SOCS2, inhibitor α of NF-κB (IκBα), NF-κB and tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) were measured with reverse transcription real-time quantitative polymerase chain reaction. ResultsCompared with the sham group, the Grooming Test score decreased in the other two groups (P < 0.05), and cavity, edema and structural disorder appeared in the spinal cord. Compared with the model group, the pathology of EODF group improved, and the Grooming Test score increased (P < 0.05). The mRNA and protein expression of AHR and SOCS2 increased (P < 0.05), the mRNA and protein expression of NF-κB decreased (P < 0.05), the mRNA expression of IκBα increased (P < 0.05), and the mRNA expression of TNF-α and IL-6 decreased (P < 0.05). ConclusionEODF may promote the recovery of motor function of forelimb in rats with SCI, and relieve damage and inflammation, which may associate with the activation of AHR/SOCS2/NF-κB signaling pathway.

Targeting glutamine utilization to block metabolic adaptation of tumor cells under the stress of carboxyamidotriazole-induced nutrients unavailability

Tumor cells have unique metabolic programming that is biologically distinct from that of corresponding normal cells. Resetting tumor metabolic programming is a promising strategy to ameliorate drug resistance and improve the tumor microenvironment. Here, we show that carboxyamidotriazole (CAI), an anticancer drug, can function as a metabolic modulator that decreases glucose and lipid metabolism and increases the dependency of colon cancer cells on glutamine metabolism. CAI suppressed glucose and lipid metabolism utilization, causing inhibition of mitochondrial respiratory chain complex I, thus producing reactive oxygen species (ROS). In parallel, activation of the aryl hydrocarbon receptor (AhR) increased glutamine uptake via the transporter SLC1A5, which could activate the ROS-scavenging enzyme glutathione peroxidase. As a result, combined use of inhibitors of GLS/GDH1, CAI could effectively restrict colorectal cancer (CRC) energy metabolism. These data illuminate a new antitumor mechanism of CAI, suggesting a new strategy for CRC metabolic reprogramming treatment.

O receptor aril de hidrocarbonetos (AhR) em melanomas: associação com mutações BRAF, com a progressão da doença e identificação de ligantes / The aryl hydrocarbon receptor (AhR) in melanomas: association with BRAF mutations, with disease progression and ligand identification

O melanoma é um tipo de câncer de pele geneticamente diverso, que surge diante das transformações em melanócitos. A mutação BRAFV600E está presente em mais de 90% de todas as mutações em BRAF, sendo assim ocorre em cerca de 50% dos casos registrados. As mutações em NRAS, ocupam o segundo lugar entre as mutações mais prevalentes, cerca de 20% dos casos. Informações sobre as assinaturas genéticas, permitiram o desenvolvimento de terapia alvo dirigida. O Vemurafenib, inibidor da quinase BRAFV600E, apresentou inicialmente resultados bastante satisfatórios, contudo existe registro de casos de recidiva e resistência. O receptor aril de hidrocarbonetos é expresso em vários componentes da pele, e assim está relacionado a homeostase e fisiopatologia da pele. Diante disso, a avaliação da expressão do receptor em um painel de linhagens mutadas para NRAS e BRAF, e BRAF resistentes, mostrou-se maior do que a encontrada em melanócitos. Também encontramos maior expressão de mRNA de AhR em linhagens de melanoma derivadas de sítio primário e metastático, mutadas para BRAFV600E, quando comparadas ao melanócito. Agregado a isto, a análise in silico no TCGA (The Cancer Genome Atlas) mostrou que há 18% de alteração genética em AhR, sendo em maior parte a alta regulação de mRNA. Também, a análise do banco público GSE12391, mostrou aumento de mRNA de AhR na fase de crescimento vertical do melanoma. Assim, concluímos que há maior expressão de mRNA e sua importância nas fases de desenvolvimento do melanoma, tanto nos processos iniciais quanto em processos de migração, invasão e metástase. Ainda, encontramos maior mRNA do receptor em linhagens resistentes ao Vemurafenib. Este resultado sustenta a hipótese de que AhR pode ser considerado um marcador de resistência em melanomas. O AhR, inicialmente no citoplasma, quando ativado pode atuar como fator de transcrição regulando vários genes que apresentam sequências definidas, participando de respostas carcinogênicas. Compostos halogenados e moléculas endógenas derivadas das vias de metabolização do triptofano são agonistas do receptor. Anteriormente, nosso grupo mostrou que linhagens de melanoma incubadas com triptamina e DMT exibiram menor clonogenicidade. Diante de uma literatura escassa sobre o papel do DMT no melanoma e com base nestes resultados, nosso objetivo foi avaliar o papel de AhR nesta interface DMT-melanoma. Para isto, nosso objetivo foi construir linhagem editada geneticamente para AhR através da ferramenta CRISPR-Cas9. Vários foram os esforços, sem sucesso, utilizados nas tentativas de comprovar a manutenção de células editadas na cultura. Atrelamos a este resultado a possibilidade de haver duas subpopulações editadas geneticamente pós CRISPR-Cas9, onde uma destas manteve o padrão de crescimento semelhante às células wild type. Devido a este crescimento diferencial, não obtivemos congruências nos ensaios e postulamos a perda do possível nocaute. A partir disso, realizamos ensaios de interactoma para avaliar a interação de DMT-AhR. Nosso resultado sugere a interação de DMT ao receptor sigma 1, e não ao receptor aril de hidrocarbonetos. Desta forma, o interactoma sustenta a hipótese de que DMT não é um ligante de AhR. Para certificar este resultado análises de docking associados a ensaios biológicos, avaliando o papel do receptor, devem ser realizados para averiguar a afinidade e seletividade de DMT como ligante do receptor na linhagem de melanoma

Melanoma is a genetically diverse type of skin cancer, which arises from changes in melanocytes. The BRAFV600E mutation is present in more than 90% of all BRAF mutations, so it occurs in about 50% of registered cases. Mutations in NRAS occupy the second place among the most prevalent mutations, about 20% of cases. Information on genetic signatures allowed the development of targeted therapy. vemurafenib, kinase inhibitor BRAFV600E, initially presented very satisfactory results, however there is a record of cases of relapse and resistance. The aryl hydrocarbon receptor is expressed in several components of the skin and is thus related to homeostasis and skin pathophysiology. Therefore, the evaluation of receptor expression in a panel of strains mutated to NRAS and BRAF, and resistant BRAF, proved to be greater than that found in melanocytes. We also found main expression of AhR mRNA in melanoma strains derived from primary and metastatic site, mutated to BRAFV600E, when compared to melanocyte. Added to this, the in silico analysis in TCGA (The Cancer Genome Atlas) showed that there is 18% of genetic alteration in AhR, being mostly the high regulation of mRNA. Also, an analysis by the public bank GSE12391, showed an increase in AhR mRNA in the vertical growth phase of melanoma. Thus, it is concluded that there is greater expression of mRNA and its importance in the stages of development of melanoma, both in recent processes and in the processes of migration, invasion and metastasis. In addition, we found higher receptor mRNA in strains resistant to vemurafenib. This result supports the hypothesis that AhR can be considered a marker of resistance in melanomas. AhR, initially in the cytoplasm, when activated can act as a transcription factor regulating several genes that have defined sequences, participating in carcinogenic responses. Along with this, we show that along the tumor progression, there is an increase in AhR in the radial growth phase of melanoma. Halogenated compounds and endogenous molecules derived from the tryptophan metabolism pathways are receptor agonists. Previously, our group showed that melanoma strains incubated with tryptamine and DMT exhibited less clonogenicity. In view of a scarce literature on the role of DMT in melanoma and based on these results, our objective was to evaluate the role of AhR in this DMT-melanoma interface. For this, our goal was to build genetically edited strain for AhR using the CRISPR-Cas9 tool. Several efforts were unsuccessful in attempts to prove the maintenance of cells edited in the culture. We linked to this result the possibility of having two subpopulations genetically edited after CRISPR-Cas9, where one of them maintained the growth pattern like wild type cells. Due to this differential growth, we did not obtain congruence in the tests and postulated the loss of the possible knockout. From that, we performed interactome assays to evaluate the DMT-AhR interaction. Our result suggests the interaction of DMT with the sigma 1 receptor, and not the aryl hydrocarbon receptor. Thus, the interactome supports the hypothesis that DMT is not an AhR ligand. To certify this result, docking analyses associated with biological assays, evaluating the role of the receptor, should be performed to ascertain the affinity and selectivity of DMT as a ligand of the receptor in the melanoma lineage

Aryl Hydrocarbon Receptor is Involved in the Proinflammatory Cytokine Response to Cadmium / 生物医学与环境科学（英文）

Objective@#To investigate involvement of the aryl hydrocarbon receptor (AhR) in the immunomodulatory effects of cadmium (Cd).@*Methods@#The effect of Cd on AhR activation ( @*Results@#Cd increased @*Conclusion@#AhR signaling is involved in the lung leukocyte proinflammatory cytokine response to Cd. The relevance of the AhR to the cytokine response to Cd provides new insight into the mechanisms of Cd immunotoxicity.

Paeoniflorin-6'-O-benzene sulfonate ameliorates progression of adjuvant-induced arthritis by inhibiting interaction between Ahr and GRK2 of fibroblast-like synoviocytes / 中国药理学与毒理学杂志

OBJECTIVE Aryl hydrocarbon receptor (Ahr) is thought to be a crucial factor that regulates immune responses, which may be involved in the pathogenesis of autoimmune inflammation including rheumatoid arthritis (RA). The results of our group in recent years have shown that CP-25, a novel ester derivative of paeoniflorin, has a good effect on improving RA animal models. However, whether the anti-arthritis effect of CP-25 is related to Ahr remains unclear. METHODS CP-25 treatment ameliorated adjuvant-induced arthritis (AA), a mouse model of RA, by inhibiting Ahr-related activities in fibroblasts like synoviocytes (FLS). AA rats were treated with CP-25 or paroxetine from day 17 to 33 after immunization. RESULTS CP-25 alleviated arthritis symptoms and the pathological changes, decreased the expression of Ahr in the synovium and FLS of AA rats. Besides, treatment with CP-25 reduced the proliferation and migration of MH7A caused by Ahr activation. In addition, we also demonstrated that CP-25 down-regulated the co-expres?sion and co-localization of Ahr and G protein-coupled receptor kinase 2 (GRK2) in MH7A. CONCLUSION The data pre?sented here demonstrated that CP-25 suppressed FLS dysfunction in rats with AA, which were associated with reduced Ahr activation and the interaction between Ahr and GRK2.

Functional metabolomics reveal the role of AHR/GPR35 mediated kynurenic acid gradient sensing in chemotherapy-induced intestinal damage

Intestinal toxicity induced by chemotherapeutics has become an important reason for the interruption of therapy and withdrawal of approved agents. In this study, we demonstrated that chemotherapeutics-induced intestinal damage were commonly characterized by the sharp upregulation of tryptophan (Trp)-kynurenine (KYN)-kynurenic acid (KA) axis metabolism. Mechanistically, chemotherapy-induced intestinal damage triggered the formation of an interleukin-6 (IL-6)-indoleamine 2,3-dioxygenase 1 (IDO1)-aryl hydrocarbon receptor (AHR) positive feedback loop, which accelerated kynurenine pathway metabolism in gut. Besides, AHR and G protein-coupled receptor 35 (GPR35) negative feedback regulates intestinal damage and inflammation to maintain intestinal integrity and homeostasis through gradually sensing kynurenic acid level in gut and macrophage, respectively. Moreover, based on virtual screening and biological verification, vardenafil and linagliptin as GPR35 and AHR agonists respectively were discovered from 2388 approved drugs. Importantly, the results that vardenafil and linagliptin significantly alleviated chemotherapy-induced intestinal toxicity

Phosphorylation regulates cullin-based ubiquitination in tumorigenesis

Cullin-RING ligases (CRLs) recognize and interact with substrates for ubiquitination and degradation, and can be targeted for disease treatment when the abnormal expression of substrates involves pathologic processes. Phosphorylation, either of substrates or receptors of CRLs, can alter their interaction. Phosphorylation-dependent ubiquitination and proteasome degradation influence various cellular processes and can contribute to the occurrence of various diseases, most often tumorigenesis. These processes have the potential to be used for tumor intervention through the regulation of the activities of related kinases, along with the regulation of the stability of specific oncoproteins and tumor suppressors. This review describes the mechanisms and biological functions of crosstalk between phosphorylation and ubiquitination, and most importantly its influence on tumorigenesis, to provide new directions and strategies for tumor therapy.

Proteomics and metabolic phenotyping define principal roles for the aryl hydrocarbon receptor in mouse liver

Dioxin-like molecules have been associated with endocrine disruption and liver disease. To better understand aryl hydrocarbon receptor (AHR) biology, metabolic phenotyping and liver proteomics were performed in mice following ligand-activation or whole-body genetic ablation of this receptor. Male wild type (WT) and

Resistant starch supplementation effects on plasma indole 3-acetic acid and aryl hydrocarbon receptor mRNA expression in hemodialysis patients: Randomized, double blind and controlled clinical trial / Efeitos da suplementação de amido resistente no ácido indol-3-acético plasmático e na expressão do mRNA do receptor aril-hidrocarboneto em pacientes em hemodiálise: ensaio clínico randomizado, duplo-cego e controlado

ABSTRACT Introduction: Gut microbiota imbalance is linked to high uremic toxins production such as indole-3-acetic acid (IAA) in chronic kidney disease patients. This toxin can activate the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor involved with inflammation. Strategies to restore gut microbiota balance can be associated with reduced production of IAA and its deleterious effects. This study aimed to evaluate prebiotic resistant starch (RS) supplementation effects on IAA plasma levels and AhR mRNA expression in CKD patients on hemodialysis (HD). Methods: This randomized, double-blind and placebo-controlled clinical trial evaluated forty-two stable HD patients allocated in RS (n=22) or placebo (n=20) groups. Patients received, alternately, cookies and sachets containing 16 g/day of RS (Hi-Maize 260®) or manioc flour for four weeks. Fasting pre-dialysis blood samples were collected and IAA plasma levels measured by high performance liquid chromatography. Peripheral blood mononuclear cells were isolated and processed for AhR and nuclear factor kappa B (NF-κB) mRNA expression analyzes by quantitative real-time PCR. Anthropometric and biochemical parameters, as well as food intake were also evaluated. Results: Thirty-one patients completed the study, 15 in the RS group and 16 in the placebo group. Although there was no significant alteration in IAA plasma levels, neither in AhR mRNA expression and NF-κB mRNA expression after RS supplementation, a positive correlation (r=0.48; p=0.03) was observed between IAA plasma levels and AhR expression at baseline. Conclusion: Even though prebiotic RS supplementation did not influence IAA levels or AhR expression, their positive association reinforces a possible interaction between them.

RESUMO Introdução: O desequilíbrio da microbiota intestinal associa-se à alta produção de toxinas urêmicas tais como ácido indol-3-acético (AIA), em renais crônicos. Essa toxina ativa o receptor aril hidrocarboneto (AhR) - fator de transcrição ativado por ligante, na inflamação. Restaurar o equilíbrio da microbiota intestinal associa-se à produção reduzida de AIA e efeitos deletérios. Avaliamos os efeitos da suplementação de amido resistente prebiótico (AR) sobre AIA sérico e expressão de AhR mRNA em renais crônicos em HD. Métodos: Estudo clínico randomizado, duplo-cego, controlado por placebo, com 42 pacientes em HD, nos grupos AR (n = 22) ou placebo (n = 20). Os pacientes receberam, alternadamente, biscoitos e sachês com 16 g/dia de AR ou polvilho - 4 semanas. Coletamos amostras de sangue em jejum pré-diálise e medimos níveis séricos de AIA por cromatografia líquida de alta eficiência. Isolamos e processamos as células mononucleares do sangue periférico para avaliar expressão AhR mRNA e NF-κB por PCR quantitativo em tempo real. Avaliamos parâmetros antropométricos, bioquímicos e ingestão alimentar. Resultados: 31 pacientes, 15 AR e 16 no placebo. Apesar de não apresentarem alteração significativa nos níveis de AIA, nas expressões de AhR ou NF-κB mRNA pós- suplementação com AR, foi verificada uma correlação positiva (r = 0,48; p = 0,03) entre AIA sérico e expressão de AhR na linha basal. Conclusão: Embora a suplementação com o prebiótico de AR não tenha influenciado os níveis de AIA ou a expressão de AhR, sua associação positiva reforça possível interação entre eles.

Lack of association between multiple polymorphisms in aryl hydrocarbon receptor (AhR) gene and cancer susceptibility

BACKGROUND@#The aryl hydrocarbon receptor (AhR) is commonly known as an environmental sensor. Polymorphisms in AhR gene have been implicated in susceptibility to cancer. However, the results were controversial. This study was conducted to quantitatively summarize the association between AhR polymorphisms and cancer risk by meta-analysis.@*METHODS@#Relevant reports were searched in four databases (Embase, PubMed, Wanfang, and China National Knowledge Infrastructure). We used pooled odds ratio (OR) and 95% confidence interval (95% CI) to evaluate the strength of the association in both standard and cumulative meta-analysis. Subgroup and sensitivity analysis was also performed, and between-study heterogeneity and publication bias were checked.@*RESULTS@#A total of seventeen studies referring to three AhR polymorphisms (rs2066853, rs7796976, and rs2074113) were identified, and 9557 cases and 10038 controls were included. There was no statistically significant association of AhR rs2066853 polymorphism with cancer risk in the overall population, and the negative results were repeated in subgroup analysis by the ethnicity and cancer type. Concerning AhR rs7796976 or rs2074113 polymorphism, no significant correlation was detected. Moreover, these non-significant findings were stable in sensitivity analysis, and the cumulative meta-analysis indicated a trend of no significant link between this three AhR polymorphisms and cancer risk as more data accumulated over time.@*CONCLUSION@#This meta-analysis provides evidence that the rs2066853, rs7796976, or rs2074113 polymorphism in AhR gene is not a susceptible predictor of cancer. Further clinical and functional investigation between AhR polymorphisms and cancer susceptibility are needed.

Xenobiotic receptors in mediating the effect of sepsis on drug metabolism

Sepsis is an infection-induced systemic inflammatory syndrome. The immune response in sepsis is characterized by the activation of both proinflammatory and anti-inflammatory pathways. When sepsis occurs, the expression and activity of many inflammatory cytokines are markedly affected. Xenobiotic receptors are chemical-sensing transcription factors that play essential roles in the transcriptional regulation of drug-metabolizing enzymes (DMEs). Xenobiotic receptors mediate the functional crosstalk between sepsis and drug metabolism because the inflammatory cytokines released during sepsis can affect the expression and activity of xenobiotic receptors and thus impact the expression and activity of DMEs. Xenobiotic receptors in turn may affect the clinical outcomes of sepsis. This review focuses on the sepsis-induced inflammatory response and xenobiotic receptors such as pregnane X receptor (PXR), aryl hydrocarbon receptor (AHR), glucocorticoid receptor (GR), and constitutive androstane receptor (CAR), DMEs such as CYP1A, CYP2B6, CYP2C9, and CYP3A4, and drug transporters such as p-glycoprotein (P-gp), and multidrug resistance-associated protein (MRPs) that are affected by sepsis. Understanding the xenobiotic receptor-mediated effect of sepsis on drug metabolism will help to improve the safe use of drugs in sepsis patients and the development of new xenobiotic receptor-based therapeutic strategies for sepsis.

The gut microbiome: an orchestrator of xenobiotic metabolism

Microbes inhabiting the intestinal tract of humans represent a site for xenobiotic metabolism. The gut microbiome, the collection of microorganisms in the gastrointestinal tract, can alter the metabolic outcome of pharmaceuticals, environmental toxicants, and heavy metals, thereby changing their pharmacokinetics. Direct chemical modification of xenobiotics by the gut microbiome, either through the intestinal tract or re-entering the gut enterohepatic circulation, can lead to increased metabolism or bioactivation, depending on the enzymatic activity within the microbial niche. Unique enzymes encoded within the microbiome include those that reverse the modifications imparted by host detoxification pathways. Additionally, the microbiome can limit xenobiotic absorption in the small intestine by increasing the expression of cell-cell adhesion proteins, supporting the protective mucosal layer, and/or directly sequestering chemicals. Lastly, host gene expression is regulated by the microbiome, including CYP450s, multi-drug resistance proteins, and the transcription factors that regulate them. While the microbiome affects the host and pharmacokinetics of the xenobiotic, xenobiotics can also influence the viability and metabolism of the microbiome. Our understanding of the complex interconnectedness between host, microbiome, and metabolism will advance with new modeling systems, technology development and refinement, and mechanistic studies focused on the contribution of human and microbial metabolism.

Expression and clinical significance of aryl hydrocarbon receptor in peripheral blood and skin lesions of patients with atopic dermatitis / 中华皮肤科杂志

Objective To detect levels of aryl hydrocarbon receptor (AhR) and its downstream molecules in peripheral blood mononuclear cells (PBMCs) and sera from patients with atopic dermatitis (AD),and to analyze the correlation of their expression with serum cytokines and the severity of AD.Methods Real-time quantitative PCR (RT-PCR) was performed to analyze mRNA expression of AhR,cytochrome P4501A (CYP1A1),AhR repressor (AHRR),AhR nuclear translocator (ARNT) in PBMCs from 29 AD patients and 17 healthy controls,enzyme-linked immunosorbent assay (ELISA) to detect serum levels of interleukin (IL)-1β,IL-6,tumor necrosis factor (TNF)-α,IL-4,IL-22 and AhR in the AD patients,and immunohistochemical study to determine AhR expression in skin lesions of the AD patients and normal skin tissues of 21 patients with pigmented nevus.Measurement data were compared by using unpaired Student's t test,enumeration data were compared by using chi-square test,and correlations between indices were analyzed by using Pearson correlation analysis.Results The serum level of AhR was significantly higher in the AD group (41.26 ± 4.52 pmol/L) than in the healthy control group (33.73 ± 2.49 pmol/L,t =6.507,P ＜ 0.001).Compared with the healthy control group,the AD group showed significantly increased mRNA expression ofAhR (1.572 ± 0.392 vs.1.000 ± 0.173,t =6.819,P =0.007),AHRR (2.402 ±1.716 vs.1.000 ± 0.788,t =3.722,P =0.039),CYP1A1 (2.258 ± 1.598 vs.1.000 ± 0.796,t =3.400,P =0.002) and ARNT (1.383 ± 0.842 vs.1.000 ± 0.586,t =1.653,P =0.105) in PBMCs.The AhR expression in skin lesions in the AD group was significantly higher than that in normal skin tissues in the control group (0.191 ± 0.041 vs.0.087 ± 0.017,t =10.036,P ＜ 0.001).In the AD group,the mRNA expression of AhR in PBMCs was positively correlated with eczema area and severity index score (r =0.448,P =0.019) and the serum IL-6 level (r =0.377,P =0.046),and the AHRR mRNA expression was positively correlated with the serum IL-1β level (r =0.467,P =0.021).Conclusion AhR and its downstream molecules were highly expressed in the AD patients compared with healthy controls,and the AhR expression was positively correlated with the serum IL-6 level and AD severity in AD patients,suggesting that the AhR signaling pathway may play a certain role in pathogenesis of AD and AhR may serve as an efficient index for evaluating AD severitv.

Effect of Dialysis on Aryl Hydrocarbon Receptor Transactivating Activity in Patients with Chronic Kidney Disease

Potential Impact of Gut Microbiota on Spinal Cord Injury (review) / 中国康复理论与实践

With the deepening of microbial research in central nervous system diseases, the role of gut microbiota in spinal cord injury has also received extensive attention. At present, it is mainly focused on exploring the changes of gut microbiota after spinal cord injury and the potential effects of aryl hydrocarbon receptor agonists, short-chain fatty acids and lipopolysaccharides produced by bacterial metabolism on secondary inflammation after injury, and it is recognized that gut microbiota or supplemental flora metabolites may be a potential pathway for the treatment of spinal cord injury.

Potential biomarkers and antagonists for fluoranthene-induced cellular toxicity of bone marrow derived mesenchymal stem cells

BACKGROUND: Fluoranthene (FR) is a common environmental pollutant that exists in a complex mixture with other polycyclic aromatic hydrocarbons (PAHs). We identified biomarkers for monitoring FR exposure and investigated the rescue effect of FR-induced cellular toxicity via aryl hydrocarbon receptor (AHR) antagonist activity in bone marrow derived mesenchymal stem cells (BM-MSCs).METHODS: Morphological changes, viability, and rescue effects of an AHR antagonist (CH223191) were examined in BM-MSCs after exposure to FR. Cytotoxic effects were assayed using the tetrazolium-based colorimetric assay. Apoptosis was measured by annexin V and propidium iodide dye-based flowcytometry assay, mitochondrial membrane potential assay, and nuclear DNA fragmentation assay. Molecular signaling pathways of apoptosis and autophagy were investigated using immunoblotting. Proteomics were performed in order to reveal the spectra of cellular damage and identify biomarkers for FR exposure.RESULTS: Exposing BM-MSCs to FR (IC₅₀=50 µM) induced cell death and morphological changes, while the AHR antagonist showed rescue effects. Autophagy was activated and mitochondrial membrane potential was decreased. Proteomic analysis identified 48 deregulated proteins (26 upregulated and 22 downregulated). Among them, annexin A6, pyruvate kinase, UDP-glucose dehydrogenase, and phospholipase A2 could be potential biomarkers for FR exposure.CONCLUSION: The exposure of BM-MSCs to FR induced remarkable alterations in cellular biology and the proteome, allowing for identification of novel biomarkers for FR exposure. Furthermore, AHR antagonists might be able to prevent cellular damage due to FR exposure.