Prenatal environmental tobacco smoke exposure increases allergic asthma risk with methylation changes in mice.

Allergic asthma remains an inadequately understood disease. In utero exposure to environmental tobacco smoke (ETS) has been identified as an environmental exposure that can increase an individual's asthma risk. To improve our understanding of asthma onset and development, we examined the effect of in utero ETS exposure on allergic disease susceptibility in an asthmatic phenotype using a house dust mite (HDM) allergen-induced murine model. Pregnant C57BL/6 mice were exposed to either filtered air or ETS during gestation, and their offspring were further exposed to HDM at 6-7 weeks old to induce allergic inflammation. Methylation in the promoter regions of allergic inflammation-related genes and genomic DNA was quantified. Exposure to HDM resulted in the onset of allergic lung inflammation, with an increased presence of inflammatory cells, Th2 cytokines (IL-4, IL-5, and IL-13), and airway remodeling. These asthmatic phenotypes were significantly enhanced when the mice had been exposed to in utero ETS. Furthermore, prenatal ETS exposure and subsequent HDM (ETS/HDM)-induced asthmatic phenotypes agree with methylation changes in the selected asthma-related genes, including IL-4, IL-5, IL-13, INF-γ, and FOXP3. Global DNA methylation was significantly lower in ETS/HDM-exposed mice than that of controls, which coincides with the results observed in lung, spleen, and blood DNAs. Prenatal ETS exposure resulted in a severe increase in allergic inflammatory responses after an HDM challenge, with corresponding methylation changes. Prenatal ETS exposure may influence developmental plasticity and result in altered epigenetic programming, leading to an increased susceptibility to asthma. Environ. Mol. Mutagen. 58:423-433, 2017. © 2017 Wiley Periodicals, Inc.

Alterations in DNA methylation corresponding with lung inflammation and as a biomarker for disease development after MWCNT exposure.

Use of multi-walled carbon nanotubes (MWCNT) is growing which increases occupational exposures to these materials. Their toxic potential makes it important to have an in-depth understanding of the inflammation and disease that develops due to exposure. Epigenetics is one area of interest that has been quickly developing to assess disease processes due to its ability to change gene expression and thus the lung environment after exposure. In this study, promoter methylation of inflammatory genes (IFN-γ and TNF-α) was measured after MWCNT exposure using the pyrosequencing assay and found to correlate with initial cytokine production. In addition, methylation of a gene involved in tissue fibrosis (Thy-1) was also altered in a way that matched collagen deposition. In addition to using epigenetics to better understand disease processes, it has also been used as a biomarker of exposure and disease. In this study, global methylation was determined in the lung to ascertain whether MWCNT alter global methylation at the site of exposure and if those alterations coincide with disease development. Then, global methylation levels were determined in the blood to ascertain whether global methylation could be used as a biomarker of exposure in a more easily accessible tissue. Using the LuUminometric Methylation Assay (LUMA) and 5-Methylcytosine (5-mC) Quantification assay, we found that MWCNT lead to DNA hypomethylation in the lung and blood, which coincided with disease development. This study provides initial data showing that alterations in gene-specific methylation correspond with an inflammatory response to MWCNT exposure. In addition, global DNA methylation in the lung and blood coincides with MWCNT-induced disease development, suggesting its potential as a biomarker of both exposure and disease development.

Alterations in DNA methylation and airway hyperreactivity in response to in utero exposure to environmental tobacco smoke.

Growing evidence indicates that prenatal exposure to maternal smoking is a risk factor for the development of asthma in children. However, the effects of prenatal environmental tobacco smoke (ETS) exposure on the genome and lung immune cells are unclear. This study aims to determine whether in utero ETS exposure alters DNA methylation patterns and increases airway hyperreactivity (AHR) and inflammation. Pregnant C57BL/6 mice were exposed daily to a concentration of 1.0 mg/m(3) ETS. AHR was determined in the 6-week-old offspring by measurement of airway resistance. Global and gene promoter methylation levels in lung DNA from offspring were analyzed by luminometric methylation and pyrosequencing assays, respectively. Offspring exposed to ETS showed a marked increase in the number of alveolar macrophages in the bronchoalveolar lavage fluid and level of IL-13 in the airways compared with offspring of filtered-air exposed dams (controls). ETS exposure significantly augmented AHR compared with controls. In the methylation analysis, ETS-exposed offspring had a significantly lower level of global DNA methylation than the controls. We observed a significant increase in IFN-γ, and significant decrease in IL-13 methylation levels in the ETS group compared with controls. Collectively, these data suggest that in utero ETS exposure increases the risk of pulmonary inflammation and AHR through altered DNA methylation, but additional studies are needed to fully determine the causal link between changes in methylation and cytokines levels, as well as AHR.

The Association of LINE-1 Hypomethylation with Age and Centromere Positive Micronuclei in Human Lymphocytes.

Global hypomethylation in white blood cell (WBC) DNA has recently been proposed as a potential biomarker for determining cancer risk through genomic instability. However, the amplitude of the changes associated with age and the impacts of environmental factors on DNA methylation are unclear. In this study, we investigated the association of genomic hypomethylation with age, cigarette use, drinking status and the presence of centromere positive micronuclei (MNC+)-a biomarker for age-dependent genomic instability. Genomic hypomethylation of the repetitive element LINE-1 was measured in WBC DNA from 32 healthy male volunteers using the pyrosequencing assay. We also measured MNC+ with the micronucleus-centromere assay using a pan-centromeric probe. Possibly due to the small sample size and resulting low statistical power, smoking and drinking status had no significant effect on LINE-1 hypomethylation or the occurrence of MNC+. Consequently, we did not include them in further analyses. In contrast, LINE-1 hypomethylation and age significantly predicted MNC+; therefore, we examined whether LINE-1 hypomethylation plays a role in MNC+ formation by age, since genomic hypomethylation is associated with genomic instability. However, LINE-1 hypomethylation did not significantly mediate the effect of age on MNC+. Our data indicate that the repetitive element LINE-1 is demethylated with age and increasing MNC+ frequency, but additional studies are needed to fully understand the relation between genomic DNA hypomethylation, age and genomic instability.

Adverse effects of wood smoke PM(2.5) exposure on macrophage functions.

Epidemiological studies have shown a correlation between chronic biomass smoke exposure and increased respiratory infection. Pulmonary macrophages are instrumental in both the innate and the adaptive immune responses to respiratory infection. In the present study, in vitro systems were utilized where alveolar macrophages (AM) and bone marrow-derived macrophages (BMdM) were exposed to concentrated wood smoke-derived particulate matter (WS-PM) and mice were exposed in vivo to either concentrated WS-PM or inhaled WS. In vivo studies demonstrated that WS-exposed mice inoculated with Streptococcus pneumoniae had a higher bacterial load 24 h post-exposure, and corresponding AM were found to have decreased lymphocyte activation activity. Additionally, while classic markers of inflammation (cellular infiltration, total protein, neutrophils) were not affected, there were changes in pulmonary macrophages populations, including significant decreases in macrophages expressing markers of activation in WS-exposed mice. The lymphocyte activation activity of WS-PM-exposed AM was significantly suppressed, but the phagocytic activity appeared unchanged. In an effort to determine a pathway for WS-induced suppression, RelB activation, assessed by nuclear translocation, was observed in AM exposed to either inhaled WS or instilled WS-PM. Finally, an analysis of WS-PM fractions determined the presence of 4-5 polycyclic aromatic hydrocarbons (PAHs), and preliminary work suggests a potential role for these PAHs to alter macrophage functions. These studies show a decreased ability of WS-exposed pulmonary macrophages to effectively mount a defense against infection, the effect lasts at least a week post-exposure, and appears to be mediated via RelB activation.

Impact of implementing 5 potentially better respiratory practices on neonatal outcomes and costs.

OBJECTIVE: We implemented 5 potentially better practices to limit mechanical ventilation (MV), supplemental oxygen, and bronchopulmonary dysplasia in newborn infants born before 33 weeks' gestation. METHODS: The methods used in this study included (1) exclusive use of bubble continuous positive airway pressure (bCPAP), (2) provision of bCPAP in the delivery room, (3) strict intubation criteria, (4) strict extubation criteria, and (5) prolonged CPAP to avoid supplemental oxygen. We excluded outborn infants and those with major anomalies and obstetric complications from analysis. RESULTS: Demographics were similar in 61 infants born before and 60 born after implementation. For infants born at 26 to 32(6/7) weeks' gestation, intubation (first 72 hours) decreased from 52% to 11% (P < .0001) and surfactant use decreased from 48% to 14% (P=.0001). In all infants, the mean ± SD fraction of inspired oxygen requirement (first 24 hours) decreased from 0.27 ± 0.08 to 0.24 ± 0.05 (P=.0005), days of oxygen decreased from 23.5 ± 44.5 to 9.3 ± 22.0 (P=.04), and days of MV decreased from 8.8 ± 27.8 to 2.2 ± 6.2 (P=.005). Hypotension decreased from 33% to 15% (P=.03). The percentage of infants with bronchopulmonary dysplasia was 17% before and 8% after (P=.27). Nurse staffing ratios remained unchanged. CONCLUSIONS: Implementation of these potentially better practices reduced the need for MV, surfactant, and supplemental oxygen as well as reduced hypotension among infants born before 33 weeks' gestation without adverse consequences. The costs for equipment and surfactant were lower.

Role of the serotonergic system in reduced pulmonary function after exposure to methamphetamine.

Although use of methamphetamine (MA) by smoking is the fastest growing method of administration, very limited data are available describing the effects of smoked MA. Using a murine inhalation exposure system, we explored the pulmonary effects of low-dose acute inhalation exposure to MA vapor (smoke). Inhalation of MA vapor resulted in transiently reduced pulmonary function, as measured by transpulmonary resistance, dynamic compliance, and whole-body plethysmography compared with unexposed control animals. These changes were associated with an approximately 34% reduction in serotonin (5-hydroxytryptamine [5-HT]) metabolism/inactivation to 5-hydroxyindolacetic acid, and a nearly 40% reduction in monoamine oxidase (MAO)-A activity in the lung. Pretreatment of mice with a selective 5-HT reuptake inhibitor completely ablated the MA-induced changes in pulmonary function, confirming a key role for the 5-HT transporter (serotonin transporter [SERT]) and the serotonergic system in this effect. Immunofluorescent staining of mouse lung tissue confirmed high expression of SERT in airway epithelial cells. Using mouse airway epithelial cell line, LA-4, and purified human MAO-A, it was demonstrated that MA impedes 5-HT metabolism through direct inhibition of MAO-A activity in vitro. Together, these data demonstrate that low-dose exposure to MA results in reduced pulmonary function mediated via SERT and subsequent perturbation of 5-HT metabolism in the lung. This supports a role for the serotonergic system in MA-mediated pulmonary effects.