scholarly journals The Aryl Hydrocarbon Receptor and the Maintenance of Lung Health

2018 ◽  
Vol 19 (12) ◽  
pp. 3882 ◽  
Author(s):  
Necola Guerrina ◽  
Hussein Traboulsi ◽  
David Eidelman ◽  
Carolyn Baglole

Much of what is known about the Aryl Hydrocarbon Receptor (AhR) centers on its ability to mediate the deleterious effects of the environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; dioxin). However, the AhR is both ubiquitously-expressed and evolutionarily-conserved, suggesting that it evolved for purposes beyond strictly mediating responses to man-made environmental toxicants. There is growing evidence that the AhR is required for the maintenance of health, as it is implicated in physiological processes such as xenobiotic metabolism, organ development and immunity. Dysregulation of AhR expression and activity is also associated with a variety of disease states, particularly those at barrier organs such as the skin, gut and lungs. The lungs are particularly vulnerable to inhaled toxicants such as cigarette smoke. However, the role of the AhR in diseases such as chronic obstructive pulmonary disease (COPD)—a respiratory illness caused predominately by cigarette smoking—and lung cancer remains largely unexplored. This review will discuss the growing body of literature that provides evidence that the AhR protects the lungs against the damaging effects of cigarette smoke.

2021 ◽  
Author(s):  
Simone Morris ◽  
Kathryn Wright ◽  
Vamshikrishna Malyla ◽  
Warwick J Britton ◽  
Philip M Hansbro ◽  
...  

AbstractCigarette smoke (CS)-induced inflammation leads to a range of diseases including chronic obstructive pulmonary disease and cancer. Environmental factors including gut microbiota make up are major modifying factors that determine the severity of cigarette smoke-induced pathology. Adult zebrafish display increased inflammatory cytokine transcription when exposed to cigarette smoke extract (CSE) but incongruously do not produce a mucosal leukocytic inflammation phenotype. Zebrafish embryos and larvae have been used to model the effects of cigarette smoking on a range of physiological processes and offer an amenable platform for screening modifiers of cigarette smoke-induced pathologies. Here we exposed zebrafish larvae to CSE and showed that it was toxic and we characterised a CSE-induced leukocytic inflammatory phenotype with increased neutrophilic and macrophage responses. The CSE-induced phenotype was exacerbated by co-exposure to microbiota from the faeces of CS-exposed mice, but not control mice. Microbiota could be recovered from the gut of zebrafish and studied in isolation. This demonstrates the utility of the zebrafish-CSE exposure platform for identifying environmental modifiers of cigarette smoking-associated pathology and demonstrates that the CS-exposed mouse gut microbiota potentiates the inflammatory effects of CSE across host species.


2021 ◽  
Vol 12 ◽  
Author(s):  
Angela Rico de Souza ◽  
Hussein Traboulsi ◽  
Xinyu Wang ◽  
Jorg H. Fritz ◽  
David H. Eidelman ◽  
...  

Cigarette smoke is a prevalent respiratory toxicant that remains a leading cause of death worldwide. Cigarette smoke induces inflammation in the lungs and airways that contributes to the development of diseases such as lung cancer and chronic obstructive pulmonary disease (COPD). Due to the presence of aryl hydrocarbon receptor (AhR) ligands in cigarette smoke, activation of the AhR has been implicated in driving this inflammatory response. However, we have previously shown that the AhR suppresses cigarette smoke-induced pulmonary inflammation, but the mechanism by which the AhR achieves its anti-inflammatory function is unknown. In this study, we use the AhR antagonist CH-223191 to inhibit AhR activity in mice. After an acute (3-day) cigarette smoke exposure, AhR inhibition was associated with significantly enhanced neutrophilia in the airways in response to cigarette smoke, mimicking the phenotype of AhR-deficient mice. We then used genetically-modified mouse strains which express an AhR that can bind ligand but either cannot translocate to the nucleus or bind its cognate response element, to show that these features of the AhR pathway are not required for the AhR to suppress pulmonary neutrophilia. Finally, using the non-toxic endogenous AhR ligand FICZ, we provide proof-of-concept that activation of pulmonary AhR attenuates smoke-induced inflammation. Collectively, these results support the importance of AhR activity in mediating its anti-inflammatory function in response to cigarette smoke. Further investigation of the precise mechanisms by which the AhR exerts is protective functions may lead to the development of therapeutic agents to treat people with chronic lung diseases that have an inflammatory etiology, but for which few therapeutic options exist.


2021 ◽  
Vol 22 (18) ◽  
pp. 9988
Author(s):  
Han-Lin Hsu ◽  
Hong-Kai Chen ◽  
Chi-Hao Tsai ◽  
Po-Lin Liao ◽  
Yen-Ju Chan ◽  
...  

Aryl hydrocarbon receptor (AHR) genomic pathway has been well-characterized in a number of respiratory diseases. In addition, the cytoplasmic AHR protein may act as an adaptor of E3 ubiquitin ligase. In this study, the physiological functions of AHR that regulate cell proliferation were explored using the CRISPR/Cas9 system. The doubling-time of the AHR-KO clones of A549 and BEAS-2B was observed to be prolonged. The attenuation of proliferation potential was strongly associated with either the induction of p27Kip1 or the impairment in mitogenic signal transduction driven by the epidermal growth factor (EGF) and EGF receptor (EGFR). We found that the leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1), a repressor of EGFR, was induced in the absence of AHR in vitro and in vivo. The LRIG1 tends to degrade via a proteasome dependent manner by interacting with AHR in wild-type cells. Either LRIG1 or a disintegrin and metalloprotease 17 (ADAM17) were accumulated in AHR-defective cells, consequently accelerating the degradation of EGFR, and attenuating the response to mitogenic stimulation. We also affirmed low AHR but high LRIG1 levels in lung tissues of chronic obstructive pulmonary disease (COPD) patients. This might partially elucidate the sluggish tissue repairment and developing inflammation in COPD patients.


Healthcare ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 53
Author(s):  
Jun Horie ◽  
Koichiro Takahashi ◽  
Shuuichi Shiranita ◽  
Kunihiko Anami ◽  
Shinichiro Hayashi

This study’s objective was to examine the characteristics of patients with chronic obstructive pulmonary disease (COPD) presenting with various exercise tolerance levels. A total of 235 patients with stable COPD were classified into 4 groups: (1) LoFlo + HiEx—patients with a six-minute walking distance (6MWD) ≥350 m and percentage of predicted forced expiratory volume in 1 s (%FEV1.0) <50%; (2) HiFlo + HiEx—patients with a 6MWD ≥350 m and a %FEV1.0 ≥50%; (3) LoFlo + LoEx—patients with a 6MWD < 350 m and %FEV1.0 < 50%; and (4) HiFlo + LoEx—patients with a 6MWD <350 m and %FEV1.0 ≥ 50%. Aspects of physical ability in the HiFlo + LoEx group were significantly lower than those in the HiFlo + HiEx group. The HiFlo + LoEx group was characterized by a history of hospitalization for respiratory illness within the past year, treatment with at-home oxygen therapy, and lacking daily exercise habits. Following three months of pulmonary rehabilitation, the LoFlo + HiEx group significantly improved in the modified Medical Research Council dyspnea score, maximum gait speed, and 6MWD, while the HiFlo + LoEx group significantly improved in the percentage of maximal expiratory pressure, maximum gait speed, 6MWD, incremental shuttle walking distance, and St. George’s Respiratory Questionnaire score. The HiFlo + LoEx group had the greatest effect of three-month pulmonary rehabilitation compared to other groups.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Daisuke Morichika ◽  
Akihiko Taniguchi ◽  
Naohiro Oda ◽  
Utako Fujii ◽  
Satoru Senoo ◽  
...  

Abstract Background IL-33, which is known to induce type 2 immune responses via group 2 innate lymphoid cells, has been reported to contribute to neutrophilic airway inflammation in chronic obstructive pulmonary disease. However, its role in the pathogenesis of emphysema remains unclear. Methods We determined the role of interleukin (IL)-33 in the development of emphysema using porcine pancreas elastase (PPE) and cigarette smoke extract (CSE) in mice. First, IL-33−/− mice and wild-type (WT) mice were given PPE intratracheally. The numbers of inflammatory cells, and the levels of cytokines and chemokines in the bronchoalveolar lavage (BAL) fluid and lung homogenates, were analyzed; quantitative morphometry of lung sections was also performed. Second, mice received CSE by intratracheal instillation. Quantitative morphometry of lung sections was then performed again. Results Intratracheal instillation of PPE induced emphysematous changes and increased IL-33 levels in the lungs. Compared to WT mice, IL-33−/− mice showed significantly greater PPE-induced emphysematous changes. No differences were observed between IL-33−/− and WT mice in the numbers of macrophages or neutrophils in BAL fluid. The levels of hepatocyte growth factor were lower in the BAL fluid of PPE-treated IL-33−/− mice than WT mice. IL-33−/− mice also showed significantly greater emphysematous changes in the lungs, compared to WT mice, following intratracheal instillation of CSE. Conclusion These observations suggest that loss of IL-33 promotes the development of emphysema and may be potentially harmful to patients with COPD.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ying Liu ◽  
Jiawei Xu ◽  
Tian Liu ◽  
Jinxiang Wu ◽  
Jiping Zhao ◽  
...  

Abstract Background Cigarette smoke (CS) is a major risk factor for Chronic Obstructive Pulmonary Disease (COPD). Follistatin-like protein 1 (FSTL1), a critical factor during embryogenesis particularly in respiratory lung development, is a novel mediator related to inflammation and tissue remodeling. We tried to investigate the role of FSTL1 in CS-induced autophagy dysregulation, airway inflammation and remodeling. Methods Serum and lung specimens were obtained from COPD patients and controls. Adult female wild-type (WT) mice, FSTL1± mice and FSTL1flox/+ mice were exposed to room air or chronic CS. Additionally, 3-methyladenine (3-MA), an inhibitor of autophagy, was applied in CS-exposed WT mice. The lung tissues and serum from patients and murine models were tested for FSTL1 and autophagy-associated protein expression by ELISA, western blotting and immunohistochemical. Autophagosome were observed using electron microscope technology. LTB4, IL-8 and TNF-α in bronchoalveolar lavage fluid of mice were examined using ELISA. Airway remodeling and lung function were also assessed. Results Both FSTL1 and autophagy biomarkers increased in COPD patients and CS-exposed WT mice. Autophagy activation was upregulated in CS-exposed mice accompanied by airway remodeling and airway inflammation. FSTL1± mice showed a lower level of CS-induced autophagy compared with the control mice. FSTL1± mice can also resist CS-induced inflammatory response, airway remodeling and impaired lung function. CS-exposed WT mice with 3-MA pretreatment have a similar manifestation with CS-exposed FSTL1± mice. Conclusions FSTL1 promotes CS-induced COPD by modulating autophagy, therefore targeting FSTL1 and autophagy may shed light on treating cigarette smoke-induced COPD.


Nutrients ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 2098
Author(s):  
Francisca de Castro Mendes ◽  
Kirstie Ducharme-Smith ◽  
Gustavo Mora-Garcia ◽  
Saleh A. Alqahtani ◽  
Maria Stephany Ruiz-Diaz ◽  
...  

Increasing epidemiological evidence suggests that optimal diet quality helps to improve preservation of lung function and to reduce chronic obstructive pulmonary disease (COPD) risk, but no study has investigated the association of food insecurity (FI) and lung health in the general population. Using data from a representative sample of US adults who participated in the National Health and Nutrition Examination Survey (NHANES) 2007–2012 cycles, we investigated the association between FI with lung function and spirometrically defined COPD in 12,469 individuals aged ≥ 18 years of age. FI (high vs. low) was defined using the US Department of Agriculture’s Food Security Scale). Population-weighted adjusted regression models were used to investigate associations between FI, and forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), their ratio, and spirometrically defined restriction (FVC below the lower limit of normal) and airflow obstruction (COPD). The prevalence of household FI was 13.2%. High household FI was associated with lower FVC (adjusted β-coefficient −70.9 mL, 95% CI −116.6, −25.3), and with higher odds (OR) of spirometric restriction (1.02, 95% CI 1.00, 1.03). Stratified analyses showed similar effect sizes within specific ethnic groups. High FI was associated with worse lung health in a nationally representative sample of adults in the US.


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