Assessment of pulmonary fibrosis using weighted gene co-expression network analysis

For many industrial chemicals toxicological data is sparse regarding several regulatory endpoints, so there is a high and often unmet demand for NAMs that allow for screening and prioritization of these chemicals. In this proof of concept case study we propose multi-gene biomarkers of compounds' ability to induce lung fibrosis and demonstrate their application in vitro. For deriving these biomarkers we used weighted gene co-expression network analysis to reanalyze a study where the time-dependent pulmonary gene-expression in mice treated with bleomycin had been documented. We identified eight modules of 58 to 273 genes each which were particularly activated during the different phases (inflammatory; acute and late fibrotic) of the developing fibrosis. The modules' relation to lung fibrosis was substantiated by comparison to known markers of lung fibrosis from DisGenet. Finally, we show the modules' application as biomarkers of chemical inducers of lung fibrosis based on an in vitro study of four diketones. Clear differences could be found between the lung fibrosis inducing diketones and other compounds with regard to their tendency to induce dose-dependent increases of module activation as determined using a previously proposed differential activation score and the fraction of differentially expressed genes in the modules. Accordingly, this study highlights the potential use of composite biomarkers mechanistic screening for compound-induced lung fibrosis.

Cigarette smoking inhibits myoblast regeneration by promoting proteasomal degradation of NPAT protein and hindering cell cycle progression

Cigarette smoking (CS) causes skeletal muscle dysfunction, leading to sarcopenia and worse prognosis of patients with diverse systemic diseases. Here, we found that CS exposure prevented C2C12 myoblasts proliferation in a dose-dependent manner. Immunoblotting assays verified that CS exposure promoted the expression of cell cycle suppressor protein p21. Furthermore, CS exposure significantly inhibited replication-dependent (RD) histone transcription and caused S phase arrest in the cell cycle during C2C12 proliferation. Mechanistically, CS deregulated the expression levels of Nuclear Protein Ataxia-Telangiectasia Locus (NPAT/p220). Notably, the proteasome inhibitor MG132 was able to reverse the expression of NPAT in myoblasts, implying that the degradation of CS-mediated NPAT is proteasome-dependent. Overexpression of NPAT also rescued the defective proliferation phenotype induced by CS in C2C12 myoblasts. Taken together, we suggest that CS exposure induces NPAT degradation in C2C12 myoblasts and impairs myogenic proliferation through NPAT associated proteasomal-dependent mechanisms. As an application of the proteasome inhibitor MG132 or overexpression of NPAT could reverse the impaired proliferation of myoblasts induced by CS, the recovery of myoblast proliferation may be potential strategies to treat CS-related skeletal muscle dysfunction.

Oxidative Stress and Lung Fibrosis: Towards an Adverse Outcome Pathway

Lung fibrosis is a progressive fatal disease in which deregulated wound healing of lung epithelial cells drives progressive fibrotic changes. Persistent lung injury due to oxidative stress and chronic inflammation are central features of lung fibrosis. Chronic cigarette smoking causes oxidative stress and is a major risk factor for lung fibrosis. The objective of this manuscript is to develop an adverse outcome pathway (AOP) that serves as a framework for investigation of the mechanisms of lung fibrosis due to lung injury caused by inhaled toxicants, including cigarette smoke. Based on the weight of evidence, oxidative stress is proposed as a molecular initiating event (MIE) which leads to increased secretion of proinflammatory and profibrotic mediators (key event 1 (KE1)). At the cellular level, these proinflammatory signals induce the recruitment of inflammatory cells (KE2), which in turn, increase fibroblast proliferation and myofibroblast differentiation (KE3). At the tissue level, an increase in extracellular matrix deposition (KE4) subsequently culminates in lung fibrosis, the adverse outcome. We have also defined a new KE relationship between the MIE and KE3. This AOP provides a mechanistic platform to understand and evaluate how persistent oxidative stress from lung injury may develop into lung fibrosis.

Combined Pulmonary Fibrosis and Emphysema: Comparative Evidence on a Complex Condition

Combined pulmonary fibrosis and emphysema (CPFE) is a clinical syndrome characterized by upper lobe emphysema and lower lobe fibrosis manifested by exercise hypoxemia, normal lung volumes, and severe reduction of diffusion capacity of carbon monoxide. It has varying prevalence worldwide with a male predominance, and with smoking history of more than 40 pack-years being a common risk factor. The unique imaging features of CPFE emphasize its distinct entity, aiding in the timely detection of pulmonary hypertension and lung cancer, both of which are common complications. High-resolution computed tomography (HRCT) is an important diagnostic and prognostic tool, while lung cancer is an independent factor that alters the prognosis in CPFE patients. Treatment options for CPFE are limited, but smoking cessation, usual treatments of pulmonary fibrosis and emphysema, and avoidance of environmental exposures are encouraged.

Cytotoxicity and cell injuries of flavored electronic cigarette aerosol and mainstream cigarette smoke: A comprehensive in vitro evaluation

INTRODUCTION

Although electronic cigarettes (e-cigarettes) have attracted much attention due to their claimed harm-reduction effects compared with conventional cigarettes, the adverse effects of e-cigarette aerosol exposure on human health are still unclear. In this work we compared the cytotoxic effects of combustion cigarettes with four commercially available flavored electronic cigarettes and their main components on ten cell lines. Cell injury mechanism of e-cigarette aerosol and combustible cigarette smoke was also explored using cellular models.

METHODS

Eleven kinds of e-cigarettes aerosol condensates (ECSCs) and cigarette smoke constituent's condensates (CSC) were collected by Cambridge filter pad, and the nicotine contents were determined by UPLC to provide an equivalent nicotine dosage. The CCK-8 assay was used to measure the cell viability differences between ECSC and CSC. Based on RNA-seq results, we compared the effects of ECSC and CSC on various cell injury pathways. Oxidative stress and inflammatory responses were further tested by Western Blot, immunofluorescence, and qRT-PCR assays.

RESULTS

CSC was found to be more cytotoxic than flavored ECSC and their main components, and BEAS-2B cell line was the most sensitive cells by comparing the IC50 value. With prolonged exposure duration and higher doses, ECSC began to exhibit cytotoxicity at and above 72 µg/mL. The IC50 values of ECSC were 15-fold higher than that of CSC. Transcriptome analyses indicated that cell injury-related processes were enriched after the treatment of CSC. CSC could significantly induce more oxidative stress and inflammatory signals than ECSC.

CONCLUSION

ECSCs and their components induced significantly less cytotoxicity than CSC under the laboratory exposure conditions, and CSC caused much severe cell injuries. Our study adds to the body of scientific evidence for a more comprehensive safety evaluation of e-cigarette products as compared to cigarettes.

Effects of photobiomodulation as an adjunctive treatment in chronic obstructive pulmonary disease: a narrative review

Chronic obstructive pulmonary disease (COPD) is a disease characterized by chronic airway inflammation and remodeling and lung parenchymal inflammation and destruction, which result in many pulmonary and extrapulmonary manifestations. The anti-inflammatory effect of photobiomodulation (PBM) has been reported in previous studies. This review was conducted to evaluate the direct effect of PBM on lung inflammation in COPD. The other effects of PBM on modulation of peripheral and respiratory muscle metabolism and angiogenesis in lung tissues were also discussed. The databases of PubMed, Cochrane Library, and Google Scholar were searched to find the relevant studies. Keywords included PBM and related terms, COPD-related signs, and lung inflammation. A total of 12 articles were selected and reviewed in this study. Based on the present review, PBM is helpful in reducing lung inflammation through decreasing the inflammatory cytokines and chemokines at multiple levels and increasing anti-inflammatory cytokines. In addition, PBM also improves both peripheral and respiratory muscle metabolism and promote angiogenesis. This review demonstrated that PBM is a promising adjunctive treatment modality for COPD management which merits further validation.

Decellularized ECM hydrogels: prior use considerations, applications, and opportunities in tissue engineering and biofabrication

Tissue development, wound healing, pathogenesis, regeneration, and homeostasis rely upon coordinated and dynamic spatial and temporal remodeling of extracellular matrix (ECM) molecules. ECM reorganization and normal physiological tissue function, require the establishment and maintenance of biological, chemical, and mechanical feedback mechanisms directed by cell-matrix interactions. To replicate the physical and biological environment provided by the ECM in vivo, methods have been developed to decellularize and solubilize tissues which yield organ and tissue-specific bioactive hydrogels. While these biomaterials retain several important traits of the native ECM, the decellularizing process, and subsequent sterilization, and solubilization result in fragmented, cleaved, or partially denatured macromolecules. The final product has decreased viscosity, moduli, and yield strength, when compared to the source tissue, limiting the compatibility of isolated decellularized ECM (dECM) hydrogels with fabrication methods such as extrusion bioprinting. This review describes the physical and bioactive characteristics of dECM hydrogels and their role as biomaterials for biofabrication. In this work, critical variables when selecting the appropriate tissue source and extraction methods are identified. Common manual and automated fabrication techniques compatible with dECM hydrogels are described and compared. Fabrication and post-manufacturing challenges presented by the dECM hydrogels decreased mechanical and structural stability are discussed as well as circumvention strategies. We further highlight and provide examples of the use of dECM hydrogels in tissue engineering and their role in fabricating complex in vitro 3D microenvironments.

Harmful Impact of Tobacco Smoking and Alcohol Consumption on the Atrial Myocardium

Tobacco smoking and alcohol consumption are widespread exposures that are legal and socially accepted in many societies. Both have been widely recognized as important risk factors for diseases in all vital organ systems including cardiovascular diseases, and with clinical manifestations that are associated with atrial dysfunction, so-called atrial cardiomyopathy, especially atrial fibrillation and stroke. The pathogenesis of atrial cardiomyopathy, atrial fibrillation, and stroke in context with smoking and alcohol consumption is complex and multifactorial, involving pathophysiological mechanisms, environmental, and societal aspects. This narrative review summarizes the current literature regarding alterations in the atrial myocardium that is associated with smoking and alcohol.

TRPM7 restrains plasmin activity and promotes transforming growth factor-β1 signaling in primary human lung fibroblasts

Sustained exposure of the lung to various environmental or occupational toxins may eventually lead to pulmonary fibrosis, a devastating disease with no cure. Pulmonary fibrosis is characterized by excessive deposition of extracellular matrix (ECM) proteins such as fibronectin and collagens. The peptidase plasmin degrades the ECM, but protein levels of the plasmin activator inhibitor-1 (PAI-1) are increased in fibrotic lung tissue, thereby dampening plasmin activity. Transforming growth factor-β1 (TGF-β1)-induced activation of SMAD transcription factors promotes ECM deposition by enhancing collagen, fibronectin and PAI-1 levels in pulmonary fibroblasts. Hence, counteracting TGF-β1-induced signaling is a promising approach for the therapy of pulmonary fibrosis. Transient receptor potential cation channel subfamily M Member 7 (TRPM7) supports TGF-β1-promoted SMAD signaling in T-lymphocytes and the progression of fibrosis in kidney and heart. Thus, we investigated possible effects of TRPM7 on plasmin activity, ECM levels and TGF-β1 signaling in primary human pulmonary fibroblasts (pHPF). We found that two structurally unrelated TRPM7 blockers enhanced plasmin activity and reduced fibronectin or PAI-1 protein levels in pHPF under basal conditions. Further, TRPM7 blockade strongly inhibited fibronectin and collagen deposition induced by sustained TGF-β1 stimulation. In line with these data, inhibition of TRPM7 activity diminished TGF-β1-triggered phosphorylation of SMAD-2, SMAD-3/4-dependent reporter activation and PAI-1 mRNA levels. Overall, we uncover TRPM7 as a novel supporter of TGF-β1 signaling in pHPF and propose TRPM7 blockers as new candidates to control excessive ECM levels under pathophysiological conditions conducive to pulmonary fibrosis.

Mmp12 Is Upregulated by in utero Second-Hand Smoke Exposures and Is a Key Factor Contributing to Aggravated Lung Responses in Adult Emphysema, Asthma, and Lung Cancer Mouse Models

Matrix metalloproteinase-12 (Mmp12) is upregulated by cigarette smoke (CS) and plays a critical role in extracellular matrix remodeling, a key mechanism involved in physiological repair processes, and in the pathogenesis of emphysema, asthma, and lung cancer. While cigarette smoking is associated with the development of chronic obstructive pulmonary diseases (COPD) and lung cancer, in utero exposures to CS and second-hand smoke (SHS) are associated with asthma development in the offspring. SHS is an indoor air pollutant that causes known adverse health effects; however, the mechanisms by which in utero SHS exposures predispose to adult lung diseases, including COPD, asthma, and lung cancer, are poorly understood. In this study, we tested the hypothesis that in utero SHS exposure aggravates adult-induced emphysema, asthma, and lung cancer.

Methods: Pregnant BALB/c mice were exposed from gestational days 6–19 to either 3 or 10mg/m³ of SHS or filtered air. At 10, 11, 16, or 17weeks of age, female offspring were treated with either saline for controls, elastase to induce emphysema, house-dust mite (HDM) to initiate asthma, or urethane to promote lung cancer. At sacrifice, specific disease-related lung responses including lung function, inflammation, gene, and protein expression were assessed.

Results: In the elastase-induced emphysema model, in utero SHS-exposed mice had significantly enlarged airspaces and up-regulated expression of Mmp12 (10.3-fold compared to air-elastase controls). In the HDM-induced asthma model, in utero exposures to SHS produced eosinophilic lung inflammation and potentiated Mmp12 gene expression (5.7-fold compared to air-HDM controls). In the lung cancer model, in utero exposures to SHS significantly increased the number of intrapulmonary metastases at 58weeks of age and up-regulated Mmp12 (9.3-fold compared to air-urethane controls). In all lung disease models, Mmp12 upregulation was supported at the protein level.

Conclusion: Our findings revealed that in utero SHS exposures exacerbate lung responses to adult-induced emphysema, asthma, and lung cancer. Our data show that MMP12 is up-regulated at the gene and protein levels in three distinct adult lung disease models following in utero SHS exposures, suggesting that MMP12 is central to in utero SHS-aggravated lung responses.

Combined Pulmonary Fibrosis Emphysema: Role of Cigarette Smoking and Pulmonary Hypertension in a Rural Cohort

Background

Disease heterogeneity in idiopathic pulmonary fibrosis (IPF) often complicates the systematic study of disease, management of patients and clinical investigations.

Objective

To describe combined pulmonary fibrosis emphysema (CPFE) phenotype in a rural Appalachian IPF cohort with the highest smoking rates in the United States.

Methods

CPFE patients (n = 60) in a developed IPF cohort (n = 153) were characterized. Groups (CPFE vs IPF without emphysema) were categorized based on the predominant HRCT patterns of UIP (n = 109). Demographics, clinical variables, and treatment details were recorded. Kaplan–Meier survival and multivariate logistic regression analysis were performed.

Results

The prevalence of CPFE in our IPF cohort was 45% (n = 49). The CPFE group was younger (73.9 vs 78.2), had a more extensive smoking history (93.9% vs 53.3%) with greater mean smoking pack years (49.09 vs 15.39) and had lower percentage predicted DL_CO on presentation (38.35 vs 51.09) compared to IPF without emphysema group. Both groups shared equivalent higher burden of comorbidities, including pulmonary hypertension (PH) (46.9% vs 33.3%). One-fifth of patients were prescribed antifibrotics and only a subset (5%) of patients underwent lung transplantation. There was a non-significant trend towards reduced survival in CPFE (p = 0.076). Smoking status and DL_CO predicted CPFE in our cohort. Body mass index (BMI), PH, and pirfenidone use were significant predictors of mortality.

Conclusion

CPFE was highly prevalent in our rural IPF cohort. In contrast to previous studies, CPFE group was older and had higher female (approx. 30%) occurrence. A greater exposure to cigarette smoke and reduced DL_CO at diagnosis predicted CPFE. Lower BMI and PH predicted higher mortality whereas use of pirfenidone improved survival in our cohort. This study highlights a complex interaction of cigarette smoking, advanced fibrosis of UIP, PH and potential utility of antifibrotic agents in CPFE phenotype. Substantial burden of comorbidities, older age, and the limited utilization of advanced therapeutics in the cohort emphasize the challenges faced by rural Appalachian patients.

The Relationships Between Prenatal Smoking Exposure and Telomere Lengths in Fetuses, Infants, and Children: A Systematic Literature Review

OBJECTIVE

The aim of this study was to evaluate the relationships between prenatal smoking exposure and telomere lengths (TLs) in fetuses, infants, and children.

METHODS

This is a systematic review guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Databases searched were Biomedical Reference Collection, MEDLINE via PubMed, CINAHL, PsycINFO, and Google Scholar. The latest search was on October 18, 2019.

RESULTS

Seven studies met the inclusion criteria and thus were reviewed. Five of the studies showed significant inverse relationships between prenatal tobacco exposure and TLs in fetuses, infants, and children. One study showed a modification effect of the postconceptual age, indicating that older fetuses with prenatal smoking exposure had shorter TLs than their counterparts. This effect was more prominent after 93 days of postconception. Another study reported a finding that was contrary to the above results, showing that the telomeres of newborns with prenatal smoking exposure were longer than those of their counterparts.

CONCLUSION/RECOMMENDATIONS

This review shows that the impact of prenatal smoking on the health of unborn fetuses, infants, and children is an understudied area. Because of the inconsistent findings and cross-sectional study designs, more research is required, especially longitudinally studies. Nonetheless, the findings of the review provide partial evidence that prenatal smoking can potentially impact the genetic biomarker, TLs, and, thus, health of fetuses, infants, and children. The evidence confirms the current practice that pregnant women should be encouraged to stop smoking as soon as they become pregnant.

Cigarette smoke-inactivated SIRT1 promotes autophagy-dependent senescence of alveolar epithelial type 2 cells to induce pulmonary fibrosis

The senescence of alveolar epithelial type 2 (AT2) cells is implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Cigarette smoke (CS) is a strong risk factor for IPF and it is also a pro-senescent factor. Here we aimed to investigate whether and how CS induces AT2 cells senescence via a SIRT1/autophagy dependent pathway. Our results showed that CS extract (CSE) reduced autophagy and mitophagy and increased mitochondrial reactive oxygen species (mitoROS) in MLE-12 cells, an AT2 cell line. The autophagy inducer rapamycin (RAPA) and the mitochondria-targeted antioxidant mitoquinone (mitoQ) inhibited CSE-related senescence and decreased mitoROS. Next, we found that CSE promoted DNA damage, downregulated the nicotinamide adenine dinucleotide (NAD⁺)/nicotinamide adenine dinucleotide (NADH) ratio and suppressed SIRT1 activity. Activating SIRT1 with its activator SRT1720 attenuated senescence through an autophagy-dependent pathway. The NAD⁺ precursor nicotinamide mononucleotide and the poly ADP-ribose polymerase (PARP1) inhibitor olaparib also exerted anti-senescent effects by activating SIRT1. Moreover, the results showed that mitoQ and RAPA, in turn, elevated SIRT1 activity by inhibiting DNA damage. Consistent with these results, SRT1720 and mitoQ mitigated CS-induced AT2 cells senescence and lung fibrosis in vivo. Moreover, autophagy in AT2 cells was rescued by SRT1720. Taken together, our results suggested that CS-induced senescence of AT2 cells was due to decreased autophagy mediated by SIRT1 inactivation, which was attributed to competitive consumption of NAD⁺ caused by DNA damage-induced PARP1 activation. The reduction in autophagy, in turn, decreased SIRT1 activity by promoting mitochondrial oxidative stress-related DNA damage, thereby establishing a positive feedback loop between SIRT1 and autophagy in CS-induced AT2 cells senescence. Consequently, CS-inactivated SIRT1 promoted autophagy-dependent senescence of AT2 cells to induce pulmonary fibrosis.

AT-RvD1 Mitigates Secondhand Smoke-Exacerbated Pulmonary Inflammation and Restores Secondhand Smoke-Suppressed Antibacterial Immunity

Cigarette smoke is a potent proinflammatory trigger contributing to acute lung injury and the development of chronic lung diseases via mechanisms that include the impairment of inflammation resolution. We have previously demonstrated that secondhand smoke (SHS) exposure exacerbates bacterial infection-induced pulmonary inflammation and suppresses immune responses. It is now recognized that resolution of inflammation is a bioactive process mediated by lipid-derived specialized proresolving mediators that counterregulate proinflammatory signaling and promote resolution pathways. We therefore hypothesized that proresolving mediators could reduce the burden of inflammation due to chronic lung infection following SHS exposure and restore normal immune responses to respiratory pathogens. To address this question, we exposed mice to SHS followed by chronic infection with nontypeable Haemophilus influenzae (NTHI). Some groups of mice were treated with aspirin-triggered resolvin D1 (AT-RvD1) during the latter half of the smoke exposure period or during a period of smoking cessation and before infection. Treatment with AT-RvD1 markedly reduced the recruitment of neutrophils, macrophages, and T cells in lung tissue and bronchoalveolar lavage and levels of proinflammatory cytokines in the bronchoalveolar lavage. Additionally, treatment with AT-RvD1 improved Ab titers against the NTHI outer membrane lipoprotein Ag P6 following infection. Furthermore, treatment with AT-RvD1 prior to classically adjuvanted immunization with P6 increased Ag-specific Ab titers, resulting in rapid clearance of NTHI from the lungs after acute challenge. Collectively, we have demonstrated that AT-RvD1 potently reverses the detrimental effects of SHS on pulmonary inflammation and immunity and thus could be beneficial in reducing lung injury associated with smoke exposure and infection.

Inhalation exposure by cigarette smoke: Effects on the progression of bleomycin- and lipopolysaccharide-induced lung injuries in rat models

The toxic substances of cigarette smoke (CS) induce inflammatory responses in the lung by recruiting inflammatory cells. In this study, we investigated the effects of CS on the progression of lung disease in bleomycin (BLM) and lipopolysaccharide (LPS)-induced lung injury rat models. Briefly, rats were exposed to CS via inhalation (nose-only) for 28 consecutive days, for 4 h per day. Using an automatic video instillator, rats were administered a single dose of 2.5 mg/kg BLM (day 1) or 0.5 mg/kg LPS (day 26), prepared in 50 μL phosphate-buffered saline (PBS) solution. Examination of the bronchoalveolar lavage fluid (BALF) revealed that the number of neutrophils increased in a concentration-dependent manner of CS. Exposure to CS also enhanced the expression of cytokines, i.e., CCL2 (MCP-1), CCL3 (MIP-1α), CXCL2 (CINC3), CXCL10 (IP-10), TNF-α, IFN-γ, IL-2, IL-4 in the BALF of the vehicle (VC) and BLM groups in a concentration-dependent manner. In particular, the expressions of CCL2, CXCL10 and TNF-α were remarkably upregulated in the BLM + CS 300 treatment as compared to VC, while there were no differences in these cytokine levels in the serum following CS exposure. Exposure to CS resulted in compacted alveolar spaces and macrophage aggregation in the lung tissues following BLM and LPS treatments. Compared to VC, pulmonary fibrosis and chronic inflammation of bronchioloalveoli were observed in the BLM + CS treatment and inflammatory cell infiltration of bronchioloalveoli was observed in the LPS + CS treatment in a concentration-dependent manner by CS. The expression levels of CCL2 and IFN-γ in the lung tissues were increased similar to the levels obtained in BALF, in a concentration-dependent manner by CS. Taken together, these results indicate that repeated exposure to CS may exacerbate the lung injury initially caused by BLM and LPS.

Clinical characteristics of Japanese patients with chronic obstructive pulmonary disease (COPD) with comorbid interstitial lung abnormalities: A cross-sectional study

Smoking-related interstitial lung abnormalities are different from specific forms of fibrosing lung disease which might be associated with poor prognoses. Chronic obstructive pulmonary disease with comorbid interstitial lung abnormalities and that with pulmonary fibrosis are considered different diseases; however, they could share a common spectrum. We aimed to evaluate the clinical characteristics of Japanese patients with chronic obstructive pulmonary disease and comorbid interstitial lung abnormalities. In this prospective observational study, we analyzed data from the Ishinomaki COPD Network Registry. We evaluated the clinical characteristics of patients with chronic obstructive pulmonary disease with and without comorbid interstitial lung abnormalities by comparing the annualized rate of chronic obstructive pulmonary disease exacerbations per patient during the observational period. Among 463 patients with chronic obstructive pulmonary disease, 30 (6.5%) developed new interstitial lung abnormalities during the observational period. After 1-to-3 propensity score matching, we found that the annualized rate of chronic obstructive pulmonary disease exacerbations per patient during the observational period was 0.06 and 0.23 per year in the interstitial lung abnormality and control groups, respectively (P = 0.043). Our findings indicate slow progression of interstitial lung abnormality lesions in patients with pre-existing chronic obstructive pulmonary disease. Further, interstitial lung abnormality development did not significantly influence on chronic obstructive pulmonary disease exacerbation. We speculate that post-chronic obstructive pulmonary disease interstitial lung abnormalities might involve smoking-related interstitial fibrosis, which is different from specific forms of fibrosing lung disease associated with poor prognoses.

Association of Adverse Childhood Experiences with Health Risk Behaviors Among College Students in Zambia

BACKGROUND

Adverse childhood experiences (ACEs) have been linked to long-term health outcomes, while the impact of such experience has not been investigated among Zambian youth. This study examined the associations of ACEs with individual and clusters of health risk behavior among college students in Zambia.

METHOD

A total of 624 college students participated in this cross-sectional study. A self-administered questionnaire was used to collect information on their ACEs and health risk behaviors.

RESULTS

There were 58.3% (364) reporting some forms of ACEs, with 27.6% (172), 16.3% (102), and 14.4% (90) being exposed to 1, 2, and ≥ 3 ACEs, respectively. The prevalence of health risk behaviors ranged from 6.0 to 34.2%. Overall, ACEs were associated with increased risk of smoking, binge drinking, suicide attempt, risky sexual behaviors, and illicit drug use. Logistic regression suggested that participants with ≥ 3 ACEs (OR, 3.62; 95% CI, 2.14-6.13) were more likely to engage in the unhealthy cluster, characterized by the presence of any health risk behavior, than those without ACE.

CONCLUSION

ACEs were associated with individual and clustering of health risk behaviors among Zambia college students. Our study suggests that early intervention is needed to prevent long-term adverse health consequences in this population.

Functional parameters of small airways can guide bronchodilator use in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) may present comorbid obstructive lung diseases with small airway dysfunction (SAD). Existing guidelines suggest that inhaled bronchodilators should be used if the ratio of forced expiratory volume in the 1st second and forced vital capacity (FEV₁/FVC) < 0.7 in IPF. However, most IPF patients have FEV₁/FVC > 0.7 even with coexisting emphysema. We retrospectively enrolled IPF patients who were registered at our outpatient clinic. At baseline, 63 patients completed computed tomography (CT) scans, lung function measurements, and symptom questionnaires. Among these patients, 54 (85.71%) underwent antifibrotic treatment and 38 (60.32%) underwent long-acting bronchodilator treatment. The median FEV₁/FVC was 0.86. Not all patients treated with bronchodilators showed significant changes in lung function. IPF patients with SAD, determined by IOS parameters, showed significant improvement in FEV₁, FEF_25–75%, and symptom scores after bronchodilator treatment. Bronchodilator efficacy was not observed in patients without SAD. CT-confirmed emphysema was seen in 34.92% of patients. There were no changes in lung function or symptom scores after bronchodilator treatment in patients with emphysema. In conclusion, FEV₁/FVC cannot reflect the airflow limitation in IPF. Emphysema in IPF is not a deciding factor in whether patients should receive bronchodilator treatment. IOS parameters may be useful to guide bronchodilator therapy in patients with IPF coexisting with SAD.

Studying Effects of Cigarette Smoke on Pseudomonas Infection in Lung Epithelial Cells

Cigarette smoking is the major etiological cause for lung emphysema and chronic obstructive pulmonary disease (COPD). Cigarette smoking also promotes susceptibility to bacterial infections in the respiratory system. However, the effects of cigarette smoking on bacterial infections in human lung epithelial cells have yet to be thoroughly studied. Described here is a detailed protocol for the preparation of cigarette smoking extracts (CSE), treatment of human lung epithelial cells with CSE, and bacterial infection and infection determination. CSE was prepared with a conventional method. Lung epithelial cells were treated with 4% CSE for 3 h. CSE-treated cells were, then, infected with Pseudomonas at a multiplicity of infection (MOI) of 10. Bacterial loads of the cells were determined by three different methods. The results showed that CSE increased Pseudomonas load in lung epithelial cells. This protocol, therefore, provides a simple and reproducible approach to study the effect of cigarette smoke on bacterial infections in lung epithelial cells.

Chronic Obstructive Pulmonary Disease and Autophagy

Chronic Obstructive Pulmonary Disease (COPD) is a classical chronic respiratory disease with the pathological changes involving the bronchi and alveoli. Many of the risk factors of COPD can induce autophagy in different kinds of cells in lung tissue including alveolar epithelial cells, broncho epithelial cells, and fibroblasts. Over-activation of autophagy may cause emphysema by inducing autophagic cell death. However, the bronchitis and fibrosis may be mainly caused by autophagic flux blocking. Thus, understanding the role of autophagy in the pathogenesis of COPD is important for the anti-COPD drug development.

Radiation exposure alters airway deformability and bony structure displacement during laryngoscopy

Background

Prior therapeutic radiation exposure in the setting of head and neck malignancies is associated with difficult airway instrumentation. We sought to characterize the anatomic changes that produce this phenotype.

Study Design

Retrospective review.

Methods

Five individuals with prior radiation therapy to the upper aerodigestive tract (previously irradiated) and 10 with no prior history of therapeutic radiation exposure (nonirradiated) were enrolled. Computed tomography images obtained before and during laryngoscope insertion ("uninstrumented" and "instrumented", respectively) were used to reconstruct three-dimensional representations of the pharyngeal airway, hyoid, and mandible.

Results

In the instrumented state, pharyngeal airway volumes were significantly greater in nonirradiated subjects relative to previously irradiated subjects (P = .01), and overall translation of both the hyoid and mandible was also greater in nonirradiated subjects (P = .01 and .04, respectively).

Conclusion

Individuals with prior therapeutic radiation exposure to the upper aerodigestive tract differ from nonirradiated subjects with respect to airway deformation and bony structure translation during laryngoscopy.

Level of Evidence

4.

Autophagy, an important therapeutic target for pulmonary fibrosis diseases

As an evolutionarily conserved intracellular degradation pathway, autophagy is essential to cellular homeostasis. Several studies have demonstrated that autophagy showed an important effect on some pulmonary fibrosis diseases, including idiopathic pulmonary fibrosis (IPF), cystic fibrosis lung disease, silicosis and smoking-induced pulmonary fibrosis. For example, autophagy mitigates the pathological progression of IPF by regulating the apoptosis of fibroblasts and the senescence of alveolar epithelial cells. In addition, autophagy ameliorates cystic fibrosis lung disease via rescuing transmembrane conductance regulators (CFTRs) to the plasma membrane. Furthermore, autophagy alleviates the silica-induced pulmonary fibrosis by decreasing apoptosis of alveolar epithelial cells in silicosis. However, excessive macrophage autophagy aggravates the pathogenesis of silicosis fibrosis by promoting the proliferation and migration of lung fibroblasts in silicosis. Autophagy is also involved in smoking-induced pulmonary fibrosis, coal workers' pneumoconiosis, ionizing radiation-mediated pulmonary fibrosis and heavy metal nanoparticle-mediated pulmonary fibrosis. In this review, the role and signalling mechanisms of autophagy in the progression of pulmonary fibrosis diseases have been systematically analysed. It has provided a new insight into the therapeutic potential associated with autophagy in pulmonary fibrosis diseases. In conclusion, the targeting of autophagy might prove to be a prospective avenue for the therapeutic intervention of pulmonary fibrosis diseases.

Combined pulmonary fibrosis and emphysema: How does cohabitation affect respiratory functions?

PURPOSE

Combined pulmonary fibrosis and emphysema (CPFE) has emerged as a new syndrome with characteristics of both fibrosis and emphysema. We determined the impacts of radiologic emphysema severity on pulmonary function tests (PFTs), exercise capacity and mortality.

PATIENTS AND METHODS

IPF patients (n = 110) diagnosed at the Chest Diseases Clinic between September 2013 and January 2016 were enrolled in the study and followed up until June 2017. Visual and digital emphysema scores, PFTs, pulmonary artery pressure (sPAP), 6-minute walking test, composite physiologic index (CPI), and survival status were recorded. Patients with emphysema and those with pure IPF were compared.

RESULTS

The CPFE-group had a significantly greater ratio of men(p < 0.001), lower BMI (p < 0.001), lower mean PaO₂ (p = 0.005), higher mean sPAP (p = 0.014), and higher exercise desaturation (p < 0.001). The CPFE group had a significantly higher FVC(L)(p = 0.016), and lower FEV1/FVC ratio (p = 0.002), DLCO, and DLCO/VA ratio(p = 0.03 and p = 0.005, respectively). Lung volumes of the CPFE group had significantly higher VC(p = 0.017), FRC (p < 0.001), RV(p < 0.001), RV/TLC(p < 0.001), and TLC(p < 0.001). There were significant correlations between emphysema scores and FVC (L)(p = 0.01), FEV1/FVC(p = 0.001), DLCO (p = 0.003), VC(p = 0.014), FRC (L)(p < 0.001), RV(p < 0.001), TLC(p < 0.001), and RV/TLC (p < 0.001). Mortality rates were comparable between the two groups. CPI (p = 0.02) and sPAP (p = 0.01) were independent predictors of mortality in patients with CPFE.

CONCLUSIONS

The presence and severity of emphysema affects pulmonary function in IPF. Patients with CPFE have reduced diffusion capacity, more severe air trapping, worse muscle weakness, more severe exercise desaturation, and pulmonary hypertension. CPI and pulmonary hypertension are two independent risk factors for mortality in subjects with CPFE.

Mechanisms of lung disease development in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disorder that causes joint inflammation and damage. Extra-articular manifestations occur in many patients and can include lung involvement in the form of airway or parenchymal inflammation and fibrosis. Although the pathophysiology of articular RA has been extensively investigated, the mechanisms causing airway and parenchymal lung disease are not well defined. Infections, cigarette-smoking, mucosal dysbiosis, host genetics and premature senescence are all potentially important contributors to the development of lung disease in patients with RA. RA-associated lung disease (which can predate the onset of articular disease by many years) probably originates from chronic airway and alveolar epithelial injury that occurs in an individual with a genetic background that permits the development of autoimmunity, leading to chronic inflammation and subsequent airway and lung parenchymal remodelling and fibrosis. Further investigations into the specific mechanisms by which lung disease develops in RA will be crucial for the development of effective therapies. Identifying mechanisms by which environmental and host factors cooperate in the induction of autoimmunity in the lung might also help to establish the order of early events in RA.

Protein carbonylation in human bronchial epithelial cells exposed to cigarette smoke extract

Cigarette smoke is a well-established exogenous risk factor containing toxic reactive molecules able to induce oxidative stress, which in turn contributes to smoking-related diseases, including cardiovascular, pulmonary, and oral cavity diseases. We investigated the effects of cigarette smoke extract on human bronchial epithelial cells. Cells were exposed to various concentrations (2.5-5-10-20%) of cigarette smoke extract for 1, 3, and 24 h. Carbonylation was assessed by 2,4-dinitrophenylhydrazine using both immunocytochemical and Western immunoblotting assays. Cigarette smoke induced increasing protein carbonylation in a concentration-dependent manner. The main carbonylated proteins were identified by means of two-dimensional electrophoresis coupled to MALDI-TOF mass spectrometry analysis and database search (redox proteomics). We demonstrated that exposure of bronchial cells to cigarette smoke extract induces carbonylation of a large number of proteins distributed throughout the cell. Proteins undergoing carbonylation are involved in primary metabolic processes, such as protein and lipid metabolism and metabolite and energy production as well as in fundamental cellular processes, such as cell cycle and chromosome segregation, thus confirming that reactive carbonyl species contained in cigarette smoke markedly alter cell homeostasis and functions.

Objectively Measured Chronic Lung Injury on Chest CT

BACKGROUND

Tobacco smoke exposure is associated with emphysema and pulmonary fibrosis, both of which are irreversible. We have developed a new objective CT analysis tool that combines densitometry with machine learning to detect high attenuation changes in visually normal appearing lung (Norm_HA) that may precede these diseases.

METHODS

We trained the classification tool by placing 34,528 training points in chest CT scans from 297 COPDGene participants. The tool was then used to classify lung tissue in 9,038 participants as normal, emphysema, fibrotic/interstitial, or Norm_HA. Associations between the quartile of Norm_HA and plasma-based biomarkers, clinical severity, and mortality were evaluated using Jonckheere-Terpstra, pairwise Wilcoxon rank-sum tests, and multivariable linear and Cox regression.

RESULTS

A higher percentage of lung occupied by Norm_HA was associated with higher C-reactive protein and intercellular adhesion molecule 1 (P for trend for both < .001). In analyses adjusted for multiple covariates, including high and low attenuation area, compared with those in the lowest quartile of Norm_HA, those in the highest quartile had a 6.50 absolute percent lower percent predicted lower FEV₁ (P < .001), an 8.48 absolute percent lower percent predicted forced expiratory volume, a 10.78-meter shorter 6-min walk distance (P = .011), and a 56% higher risk of death (P = .003). These findings were present even in those individuals without visually defined interstitial lung abnormalities.

CONCLUSIONS

A new class of Norm_HA on CT may represent a unique tissue class associated with adverse outcomes, independent of emphysema and fibrosis.

Gprc5a depletion enhances the risk of smoking-induced lung tumorigenesis and mortality

AIMS

Lung cancer remains the leading cause of cancer incidence and mortality. Although cigarette smoke is regarded as a high risk factor for lung tumor initiation, the role of the lung tumor suppressor GPRC5A in smoking-induced lung cancer is unclear.

MAIN METHODS

We obtained two lung cancer cohorts from the TCGA and GEO databases. Bioinformatics analysis showed differential gene expression in the cohorts. Quantitative real-time PCR, Western Blot and Gprc5a^-/- mice uncovered the relationship between cigarette smoke and lung cancer in the GPRC5A deletion system in vitro and in vivo.

KEY FINDINGS

Bioinformatics analysis showed that the smoking lung cancer patients with low expression of GPRC5A had poor overall survival compared to the patients with high GPRC5A expression. Further analysis revealed that cancer-related stemness pathways such as the Hippo signaling pathway were induced in smoking patients with low GPRC5A expression. Additionally, we detected enriched expression of WNT5A and DLX5 in normal human lung epithelial 16HBE cells and human lung cancer H1299 cells in vitro. A relationship between cigarette smoke extract (NNK) and lung tumor initiation was observed in Gprc5a^-/- mice.

SIGNIFICANCE

The lung tumor suppressor gene GPRC5A played a protective role in cigarette smoke-induced lung tumor initiation, providing a target for the prevention of lung cancer development and monitoring of prognosis.

TTC3 contributes to TGF-β1-induced epithelial-mesenchymal transition and myofibroblast differentiation, potentially through SMURF2 ubiquitylation and degradation

Transforming growth factor-β (TGF-β) acts as a key cytokine in epithelial−mesenchymal transition (EMT) and myofibroblast differentiation, which are important for normal tissue repair and fibrotic diseases. Ubiquitylation and proteasomal degradation of TGF-β signaling proteins acts as a regulatory mechanism for the precise control of TGF-β signaling. SMAD-specific ubiquitin E3 ligase (SMAD ubiquitination regulatory factor 2, SMURF2) controls TGF-β signaling proteins including the TGF-β receptor (TGFR) and SMAD2/3. Here, we report that tetratricopeptide repeat domain 3 (TTC3), a ubiquitin E3 ligase, positively regulates TGF-β₁-induced EMT and myofibroblast differentiation, through inducing ubiquitylation and proteasomal degradation of SMURF2. In human bronchial epithelial cells (BEAS-2B) and normal human lung fibroblasts, TTC3 knockdown suppressed TGF-β₁-induced EMT and myofibroblast differentiation, respectively. Similarly, when TTC3 expression was suppressed, the TGF-β₁-stimulated elevation of p-SMAD2, SMAD2, p-SMAD3, and SMAD3 were inhibited. In contrast, overexpression of TTC3 caused both EMT and myofibroblast differentiation in the absence of TGF-β₁ treatment. TGF-β₁ reduced SMURF2 levels and TTC3 overexpression led to a further decrease in SMURF2 levels, while TTC3 knockdown inhibited TGF-β₁-induced SMURF2 reduction. In cell and in vitro ubiquitylation assays demonstrated TTC3-mediated SMURF2 ubiquitylation, and coimmunoprecipitation assays established the binding between SMURF2 and TTC3. TGF-β₁-induced TTC3 expression was inhibited by the knockdown of SMAD2 and SMAD3. Finally, Ttc3 mRNA levels were significantly increased and Smurf2 protein levels were significantly decreased in the lungs of mice treated with bleomycin as compared with the lungs of control mice. Collectively, these data suggest that TTC3 may contribute to TGF-β₁-induced EMT and myofibroblast differentiation, potentially through SMURF2 ubiquitylation/proteasomal degradation and subsequent inhibition of SMURF2-mediated suppression of SMAD2 and SMAD3, which in turn induces TTC3 expression.

Memantine ameliorates pulmonary inflammation in a mice model of COPD induced by cigarette smoke combined with LPS

An enhanced chronic inflammatory response in the airways has been regarded as a critical characteristic of chronic obstructive pulmonary disease (COPD). Memantine, an N-methyl-d-aspartate (NMDA) receptors antagonist, has been reported to alleviate lung inflammation. In this study, we investigated the effect and mechanism of memantine on the COPD model induced by cigarette smoke (CS) combined with LPS. Mice and RAW264.7 cells were treated with LPS in the presence or absence of CS. We performed H&E staining to analysis the lung histopathological characteristics. Cytokines (IL-6, TNF-α, and IFN-γ) levels in bronchoalveolar lavage fluid (BALF), lung tissue homogenates and RAW264.7 cell culture medium were determined. Glutamate levels in plasma and culture medium of RAW264.7 were determined. The intracellular Ca2+ flux in RAW264.7 cells was measured by fluo-3 AM staining. The protein levels of NR-1, xCT, ERK1/2, and AKT signaling in the lung tissue and cells were investigated. The result showed that CS and LPS stimulation caused inflammation response, a significant increase in the release of cytokines, including TNF-α, IL-6, and IFN-γ, the elevated release of glutamate and protein levels of NR-1 and xCT, increased Ca2+ influx, and the activation of the ERK1/2 pathway in vitro and in vivo. The above effects of CS and LPS stimulation could be significantly attenuated by memantine treatment. In conclusion, memantine can effectively ameliorate pulmonary inflammation in CS + LPS-induced COPD in mice via reducing NR-1 and xCT expression, glutamate release, Ca2+ influx, and the phosphorylation of Erk1/2. We provided a possible mechanism by which memantine ameliorates COPD in mice.

Andrographolide simultaneously augments Nrf2 antioxidant defense and facilitates autophagic flux blockade in cigarette smoke-exposed human bronchial epithelial cells

Cigarette smoking is the leading cause of chronic obstructive pulmonary disease (COPD). Cigarette smoke heightens oxidative stress and impairs autophagy, advancing COPD progression. Andrographolide is a bioactive diterpenoid lactone isolated from the plant Andrographis paniculata which has been a traditional medicinal herb for respiratory diseases. As airway epithelial cells form the first interface to be exposed to cigarette smoke, this study aimed to explore the modulatory effects of andrographolide on oxidative stress and autophagy in human bronchial epithelial BEAS-2B cells exposed to cigarette smoke extract (CSE). CSE (2%) exposure increased autophagic markers p62 and LC3B-II levels in BEAS-2B cells. Andrographolide alone increased p62 and p-p62 (S349) but not LC3B-II in BEAS-2B cells. However, in the presence of CSE, andrographolide was able to simultaneously increase LC3B-II level and enhance antioxidant defense by decreasing oxidative stress and increasing total antioxidant capacity, through upregulation of nuclear Nrf2 via the p62-Nrf2 positive feedback loop. Using RFP-GFP-LC3B transfected BEAS-2B cells exposed to CSE, andrographolide was found to impair autophagosome fusion with lysosome, which may account for the moderate increase in activated caspase 3/7 and annexin V levels. Our findings revealed for the first time that andrographolide simultaneously upregulated antioxidant defense through the p62-Nrf2 loop and moderately induced apoptosis through impairment of autophagic flux in CSE-exposed bronchial epithelium. Andrographolide facilitated cigarette smoke-induced apoptosis may be a potential toxicological outcome or may protect against chronic inflammation and aberrant DNA repair. Validation of these in-vitro findings in an experimental COPD model by andrographolide is warranted.

The role of FGF-2 in smoke-induced emphysema and the therapeutic potential of recombinant FGF-2 in patients with COPD

Although the positive effects of recombinant fibroblast growth factor-2 (rFGF-2) in chronic obstructive pulmonary disease (COPD) have been implicated in previous studies, knowledge of its role in COPD remains limited. The mechanism of FGF2 in a COPD mouse model and the therapeutic potential of rFGF-2 were investigated in COPD. The mechanism and protective effects of rFGF-2 were evaluated in cigarette smoke-exposed or elastase-induced COPD animal models. Inflammation was assessed in alveolar cells and lung tissues from mice. FGF-2 was decreased in the lungs of cigarette smoke-exposed mice. Intranasal use of rFGF-2 significantly reduced macrophage-dominant inflammation and alveolar destruction in the lungs. In the elastase-induced emphysema model, rFGF-2 improved regeneration of the lungs. In humans, plasma FGF-2 was decreased significantly in COPD compared with normal subjects (10 subjects, P = 0.037). The safety and efficacy of inhaled rFGF-2 use was examined in COPD patients, along with changes in respiratory symptoms and pulmonary function. A 2-week treatment with inhaled rFGF-2 in COPD (n = 6) resulted in significantly improved respiratory symptoms compared with baseline levels (P < 0.05); however, the results were not significant compared with the placebo. The pulmonary function test results of COPD improved numerically compared with those in the placebo, but the difference was not statistically significant. No serious adverse events occurred during treatment with inhaled rFGF-2. The loss of FGF-2 production is an important mechanism in the development of COPD. Inhaling rFGF-2 may be a new therapeutic option for patients with COPD because rFGF-2 decreases inflammation in lungs exposed to cigarette smoke.

Overexpression of Forkhead box C1 attenuates oxidative stress, inflammation and apoptosis in chronic obstructive pulmonary disease

AIM

Chronic obstructive pulmonary disease (COPD) is a disease caused by cigarette smoke, which has been emerging as a serious health problem worldwide. The aim of this study is to explore the mRNA expression profile of lung tissues from the COPD rats and to characterize the role of Forkhead box C1 (Foxc1) in COPD.

MAIN METHODS

Wistar rats were exposed to cigarette smoke during 16 weeks for COPD model establishment. The microarray was used to identify the differential gene expression in the lung of rats. Adenovirus carrying Foxc1 was administered to rats by intratracheally instillation once a week for 16 weeks. Human bronchial epithelial cell line (16HBE) cells were transfected with Foxc1 siRNA followed by incubation in the presence of CSE (10%) for 24 h. Subsequently, the pathological changes, fibrosis, apoptosis, inflammatory cytokines and oxidative stress were detected.

KEY FINDINGS

Microarray results showed an upregulation of Foxc1 in lung tissues in COPD rats. Overexpression of Foxc1 mitigated the lung injury, as evidenced by reducing alveolar fusion, inflammatory cell infiltration and oxidative stress. Additionally, the apoptosis was remarkably increased in the lung in rats exposed to cigarette smoke, which was suppressed by Foxc1 overexpression. Furthermore, downregulation of Foxc1 aggravated the inflammation, oxidative stress and apoptosis in 16HBE cells with CSE treatment.

SIGNIFICANCE

Overexpression of Foxc1 could prevent oxidative stress, inflammation responses and cell apoptosis and knockdown of Foxc1 has the opposite effect, suggesting that Foxc1 may be available for lung protection during COPD.

Vitamin D treatment abrogates the inflammatory response in paraquat-induced lung fibrosis

A high incidence of intentional or accidental paraquat (PQ) ingestion is related to irreversible lung fibrosis and no effective therapy is currently available. Vitamin D has emerged with promising results as an immunomodulatory molecule when abrogating the inflammatory responses of lung diseases. Therefore, we have investigated the role of vitamin D treatments on PQ-induced lung fibrosis in male C57/BL6 mice. Lung fibrosis was induced by a single injection of PQ (10 mg/kg; i.p.). The control group received PQ vehicle. Seven days later, after the PQ injection or the vehicle injection, the mice received vitamin D (5 μg/kg, i.p., once a day) or vehicle, for a further 7 days. Twenty-four hours after the last dose of vitamin D or the vehicle, the analysis were performed. The vitamin D treatments reduced the number of leukocytes in their BALF and they decreased the IL-6, IL-17, TGF-beta and MMP-9 levels and the abrogated collagenase deposits in their lung tissues. Conversely, the vitamin D treatments increased the resolvin D levels in their BALF. Moreover, their tracheal contractility was also significantly reduced by the vitamin D treatments. Altogether, the data that was obtained showed a promising use of vitamin D, in treating the lung fibrosis that had been induced by the PQ intoxications. This may improve its prognostic use for a non-invasive and low cost therapy.

Transgenic up-regulation of Claudin-6 decreases fine diesel particulate matter (DPM)-induced pulmonary inflammation

Claudin-6 (Cldn6) is a tetraspanin transmembrane protein that contributes to tight junctional complexes and has been implicated in the maintenance of lung epithelial barriers. In the present study, we tested the hypothesis that genetic up-regulation of Cldn-6 influences inflammation in mice exposed to short-term environmental diesel particulate matter (DPM). Mice were subjected to ten exposures of nebulized DPM (PM2.5) over a period of 20 days via a nose-only inhalation system (Scireq, Montreal, Canada). Using real-time RT-PCR, we discovered that the Cldn6 gene was up-regulated in control mice exposed to DPM and in lung-specific transgenic mice that up-regulate Cldn-6 (Cldn-6 TG). Interestingly, DPM did not further enhance Cldn-6 expression in Cldn-6 TG mice. DPM caused increased cell diapedesis into bronchoalveolar lavage fluid (BALF) from control mice; however, Cldn-6 TG mice had less total cells and PMNs in BALF following DPM exposure. Because Cldn-6 TG mice had diminished cell diapedesis, other inflammatory intermediates were screened to characterize the impact of increased Cldn-6 on inflammatory signaling. Cytokines that mediate inflammatory responses including TNF-α and IL-1β were differentially regulated in Cldn6 TG mice and controls following DPM exposure. These results demonstrate that epithelial barriers organized by Cldn-6 mediate, at least in part, diesel-induced inflammation. Further work may show that Cldn-6 is a key target in understanding pulmonary epithelial gateways exacerbated by environmental pollution.

The association of LAMB1 polymorphism and expression changes with the risk of coal workers' pneumoconiosis

BACKGROUND

Pneumoconiosis is a serious occupational disease worldwide, which is characterized by irreversible and diffuse lung fibrotic lesions. Laminin beta 1(LAMB1) is widely expressed in tissues and it is crucial for both lung morphogenesis and physiological function. In this study, we explored the association between LAMB1 rs4320486 and risk of pneumoconiosis in a Chinese population, as well as its mechanisms.

METHODS

In this case-control study, 600 CWP patients and 605 controls were genotyped for the LAMB1 rs4320486 polymorphism using TaqMan methods. Luciferase reporter assay was used to assess the LAMB1 transcriptional activities. The protein levels in cells and tissues were detected by western blot, and mRNA levels were determined by qRT-PCR.

RESULTS

Logistic regression analysis revealed that individuals with LAMB1 rs4320486 CT/TT genotypes had a significantly decreased risk of CWP (adjusted OR = 0.78, 95%CI = 0.64-0.94), compared with individuals with CC genotypes. Luciferase assays showed that the LAMB1 rs4320486(C > T) substitution could decrease the expression of LAMB1. Compared with normal groups, mRNA levels of LAMB1 were up-regulated in lung tissues of patients with pulmonary fibrosis. Additionally, expressions of LAMB1 and α-SMA were enhanced progressively, along with the development of lung fibrosis, while E-cadherin decreased.

CONCLUSIONS

In this study, the functional LAMB1 rs4320486 mutation was associated with a decreased risk of CWP in a Chinese population, probably owing to the reduced activity of LAMB1 transcription. LAMB1 expression was increased in the progress of lung fibrosis, which suggests that LAMB1 may affect the initiation and progression of pneumoconiosis, or serve as a potential biomarker of pneumoconiosis for diagnosis and genetic susceptibility.

Evaluation of whole cigarette smoke induced oxidative stress in A549 and BEAS-2B cells

Cigarette smoke is a complex and oxidative aerosol. Previous researches on the hazards of cigarette smoke mainly focused on the adverse bioeffects induced by its condensates or gas vapor phase, which ignored the dynamic processes of smoking and the cigarette smoke aging. To overcome these disadvantages, we performed air-liquid interface exposure of whole smoke, which used native and unmodified smoke and ensured the exposure similar to physiological inhalation. Our results indicated that whole cigarette smoke induced lung epithelial cells (A549) and bronchial epithelial cells (BEAS-2B) damages in cytotoxicity assays (methyl thiazoly tetrazolium and neutral red uptake assays). In addition, A549 and BEAS-2B cells showed oxidative damages in whole smoke exposure, with concentration change of several biomarkers (reduced and oxidized glutathione, malondialdehyde, 4-hydroxyhydroxy-2-nonenal, extracellular superoxide dismutase, and 8-hydroxyl deoxyguanosine). These results indicate that whole smoke-induced oxidative stress occurs in two different kinds of cells at air-liquid interface.

Cigarette Smoke-Induced Pulmonary Inflammation and Autophagy Are Attenuated in Ephx2-Deficient Mice

Cigarette smoke (CS) increases the risk of chronic obstructive pulmonary disease (COPD) by causing inflammation, emphysema, and reduced lung function. Additionally, CS can induce autophagy which contributes to COPD. Arachidonic acid-derived epoxyeicosatrienoic acids (EETs) have promising anti-inflammatory properties that may protect the heart and liver by regulating autophagy. For this reason, the effect of decreased soluble epoxide hydrolase (sEH, Ephx2)-mediated EET hydrolysis on inflammation, emphysema, lung function, and autophagy was here studied in CS-induced COPD in vivo. Adult male wild-type (WT) C57BL/6J and Ephx2^−/− mice were exposed to air or CS for 12 weeks, and lung inflammatory responses, air space enlargement (emphysema), lung function, and autophagy were assessed. Lungs of Ephx2^−/− mice had a less pronounced inflammatory response and less autophagy with mild distal airspace enlargement accompanied by restored lung function and steady weight gain. These findings support the idea that Ephx2 may hold promise as a therapeutic target for COPD induced by CS, and it may be protective property by inhibiting autophagy.

Understanding COPD-overlap syndromes

INTRODUCTION

Chronic obstructive pulmonary disease accounts for a large burden of lung disease. It can 'overlap' with other respiratory diseases including bronchiectasis, fibrosis and obstructive sleep apnea (OSA). While COPD alone confers morbidity and mortality, common features with contrasting clinical outcomes can occur in COPD 'overlap syndromes'. Areas covered: Given the large degree of heterogeneity in COPD, individual variation to treatment is adopted based on its observed phenotype, which in turn overlaps with features of other respiratory disease states such as asthma. This is coined asthma-COPD overlap syndrome ('ACOS'). Other examples of such overlapping clinical states include bronchiectasis-COPD ('BCOS'), fibrosis-COPD ('FCOS') and OSA-COPD ('OCOS'). The objective of this review is to highlight similarities and differences between the COPD-overlap syndromes in terms of risk factors, pathophysiology, diagnosis and potential treatment differences. Expert commentary: As a consequence of COPD overlap syndromes, a transition from the traditional 'one size fits all' treatment approach is necessary. Greater treatment stratification according to clinical phenotype using a precision medicine approach is now required. In this light, it is important to recognize and differentiate COPD overlap syndromes as distinct disease states compared to individual diseases such as asthma, COPD, fibrosis or bronchiectasis.

p53 and miR-34a Feedback Promotes Lung Epithelial Injury and Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal interstitial lung disease. The pathogenesis of interstitial lung diseases, including its most common form, IPF, remains poorly understood. Alveolar epithelial cell (AEC) apoptosis, proliferation, and accumulation of myofibroblasts and extracellular matrix deposition results in progressive loss of lung function in IPF. We found induction of tumor suppressor protein, p53, and apoptosis with suppression of urokinase-type plasminogen activator (uPA) and the uPA receptor in AECs from the lungs of IPF patients, and in mice with bleomycin, cigarette smoke, silica, or sepsis-induced lung injury. Treatment with the caveolin-1 scaffolding domain peptide (CSP) reversed these effects. Consistent with induction of p53, AECs from IPF lungs or mice with diverse types of lung injuries showed increased p53 acetylation and miR-34a expression with reduction in Sirt1. This was significantly reduced after treatment of wild-type mice with CSP, and uPA-deficient mice were unresponsive. Bleomycin failed to induce miR-34a in p53- or plasminogen activator inhibitor-1 (PAI-1)-deficient mice. CSP-mediated inhibition of miR-34a restored Sirt1, suppressed p53 acetylation and apoptosis in injured AECs, and prevented pulmonary fibrosis (PF). AEC-specific suppression of miR-34a inhibited bleomycin-induced p53, PAI-1, and apoptosis and prevented PF, whereas overexpression of precursor-miR-34a increased p53, PAI-1, and apoptosis in AECs of mice unexposed to bleomycin. Our study validates p53-miR-34a feedback as a potential therapeutic target in PF.

Cigarette smoke extract induces the epithelial-to-mesenchymal transition via the PLTP/TGF-β1/Smad2 pathway in RLE-6TN cells

Aim: The role of phospholipid transfer protein (PLTP) in the pathogenesis of the cigarette smoke extract (CSE)-induced epithelial-to-mesenchymal transition (EMT) has not been well described. In this study we investigated the effect of PLTP on the CSE-induced EMT of rat alveolar epithelial cells (RLE-6TN). Methods: The rats were exposed to air and cigarette smoke (CS) for 3 d and then the lungs were sectioned and examined using immunohistochemistry techniques. RLE-6TN cells were treated with different concentrations of CSE. PLTP siRNA was transfected into cells or SB431542 - an inhibitor of the transforming growth factor-β1 (TGF-β1) type I receptor - was administered prior to CSE exposure. The expression of EMT markers and PLTP was detected by qRT-PCR. The levels of PLTP, TGF-β1, p-Smad2, Smad2, and EMT proteins were analyzed by western blotting. Results: Lung injury and EMT were accompanied by up-regulation of PLTP and TGF-β1 in the CS-exposed rat model. EMT was induced by CSE in vitro, and the expression of PLTP, TGF-β1, and p-Smad2 was significantly increased after exposure to CSE (P < 0.05). Moreover, knockdown of PLTP and blocking of the TGF-β1/Smad2 pathway restrained the CSE-induced activation of the TGF-β1/Smad2 pathway and partly inhibited EMT by reversing E-cadherin expression and retarding the induction of N-cadherin and vimentin. In contrast, SB431542 had no effect on the expression of PLTP, while it ameliorated CSE-induced EMT. Conclusion: PLTP promotes the CSE-induced EMT process, in which the TGF-β1/Smad2 pathway is activated.

Cigarette smoke and decreased oxygen tension inhibit pulmonary claudin-6 expression

PURPOSE

Chronic obstructive pulmonary disease is a condition involving perturbed barrier integrity coincident with both emphysema and inflammation of the airways, and smoking is considered a major risk factor. Claudins (Cldns) stabilize barriers and contribute to tight junctions by preventing paracellular transport of extracellular fluid constituents.

METHODS

To determine Cldn6 was differentially influenced by tobacco smoke, Cldn6 was evaluated in cells and tissues by q-PCR, immunoblotting, and immunohistochemistry following exposure. Cldn6 transcriptional regulation was also assessed using luciferase reporter constructs.

RESULTS

Q-PCR and immunoblotting revealed that Cldn6 was decreased in alveolar type II-like epithelial cells (A549) and primary small airway epithelial cells when exposed to cigarette smoke extract (CSE). Cldn6 was also markedly decreased in the lungs of mice exposed to acute tobacco smoke delivered by a nose-only automated smoke machine compared to controls. Luciferase reporter assays incorporating 0.5-kb, 1.0-kb, or 2.0-kb of the Cldn6 promoter revealed decreased transcription of Cldn6 following exposure to CSE. Cldn6 transcriptional regulation was also assessed in hypoxic conditions due to low oxygen tension observed during smoking. Hypoxia and hypoxia inducible factor-1 alpha caused decreased transcription of the Cldn6 gene via interactions with putative response elements in the proximal promoter sequence.

CONCLUSIONS

These data reveal that tight junctional proteins such as Cldn6 are differentially regulated by tobacco-smoke exposure and that Cldns are potentially targeted when epithelial cells respond to tobacco smoke. Further research may show that Cldns expressed in tight junctions between parenchymal cells contribute to impaired structural integrity of the lung coincident with smoking.

Association between Traffic Air Pollution and Reduced Forced Vital Capacity: A Study Using Personal Monitors for Outdoor Workers

Background

The effects of outdoor air pollution on lung function in adults are still controversial.

Objective

Evaluate the effects of exposure to different levels of traffic-generated PM_2.5 on workers’ lung functions in São Paulo, Brazil.

Methods

To cover a wide range of exposures, 101 non-smoking workers from three occupations (taxi drivers, traffic controllers, and forest rangers) were selected for the study. After clinical evaluation, the participants were scheduled to attend four consecutive weekly visits in which they received a 24-hour personal PM_2.5 sampler and had lung function tests measured on the following day. The association between the spirometric variables and the averaged PM_2.5 levels was assessed using robust regression models adjusted for age, waist circumference, time at the job, daily work hours, diabetes or hypertension and former smoking habits.

Results

Relative to workers in the lowest exposed group (all measures < 25 μg/m³), those with the highest level of exposure (all measures > 39.6 μg/m³) showed a reduction of predicted FVC (-12.2%; CI 95%: [-20.0% to -4.4%]), a marginal reduction of predicted FEV₁ (-9.1%; CI 95%: [-19.1% to 0.9%]) and an increase of predicted FEF_25-75%/FVC (14.9%; CI 95%: [2.9% to 26.8%]) without changes of FEV₁/FVC.

Conclusions

Exposure to vehicular traffic air pollution is associated with a small but significant reduction of FVC without a reduction of FEV₁/FVC.

Quantification of Glutathione in Caenorhabditis elegans

Glutathione (GSH) is the most abundant intracellular thiol with diverse functions from redox signaling, xenobiotic detoxification, and apoptosis. The quantification of GSH is an important measure for redox capacity and oxidative stress. This protocol quantifies total GSH from Caenorhabditis elegans, an emerging model organism for toxicology studies. GSH is measured using the 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) cycling method originally created for cell and tissue samples but optimized for whole worm extracts. DTNB reacts with GSH to from a 5'-thio-2-nitrobenzoic acid (TNB) chromophore with maximum absorbance of 412 nm. This method is both rapid and sensitive, making it ideal for studies involving a large number of transgenic nematode strains.

Combined pulmonary fibrosis and emphysema: The many aspects of a cohabitation contract

Combined pulmonary fibrosis and emphysema (CPFE) is a clinical entity characterized by the coexistence of upper lobe emphysema and lower lobe fibrosis. Patients with this condition experience severe dyspnea and impaired gas exchange with preserved lung volumes. The diagnosis of the CPFE syndrome is based on HRCT imaging, showing the coexistence of emphysema and pulmonary fibrosis both in varying extent and locations within the lung parenchyma. Individual genetic background seem to predispose to the development of the disease. The risk of the development of pulmonary hypertension in patients with CPFE is high and related to poor prognosis. CPFE patients also present a high risk of lung cancer. Mortality is significant in patients with CPFE and median survival is reported between 2.1 and 8.5 years. Currently, no specific recommendations are available regarding the management of patients with CPFE. In this review we provide information on the existing knowledge on CPFE regarding the pathophysiology, clinical manifestations, imaging, complications, possible therapeutic interventions and prognosis of the disease.

Pathophysiological Factors in the Relationship between Chronological Age and Calculated Lung Age as Detected in a Screening Setting in Community-Dwelling Subjects

Aim

To explore the relationship between pathophysiological factors and premature lung aging in a cohort of community-dwelling subjects in a health-screening setting.

Methods

16,107 pharmacy customers in Germany (5954 males, 10,153 females; mean age 59.7 years) participated in a lung function screening project by providing demographic data, including smoking status and known airway conditions and performing spirometry with a Vitalograph, a spirometry screening device. Lung age was calculated from the spirometric findings, and the difference between chronological age and calculated lung age was analyzed in its relationship to the demographic data in general linear models.

Results

In the overall cohort, calculated lung age exceeded chronological age by 10.0 years. Based on the subset of non-smokers not reporting any airway conditions, Vitalograph data in this setting may underestimate FEV₁ to some degree, but this apparently had little impact on the detection of association of lung age with pathophysiological factors or the corresponding effect sizes. The most important factors associated with greater lung age based on strength of association were presence of dyspnea, being a smoker, and reporting a history of COPD or asthma. Corresponding effect sizes for the difference between age and lung age were 6.5, 5.7, 13.9, and 8.3 years over the chronological age.

Discussion and Conclusion

These data confirm the usefulness of screening devices of lung function testing for epidemiological but potentially also for pharmaco-epidemiological studies.