The Effect of Green Tea Extract on Pulmonary Inflammation in Nanoparticles-Exposed Mice.

SCOPE: Titanium dioxide nanoparticles (TiO2 NPs) are air pollutants that exacerbate chronic respiratory diseases such as asthma and Chronic Obstructive Pulmonary Disease (COPD) However, little is known about the mechanism underlying the antipollutant effects of green tea extract (GTE). This study evaluates the efficacy and mechanism of GTE on lung inflammation and fibrosis in mice exposed to TiO2 NPs. METHODS AND RESULTS: The TiO2 NPs model is induced by having mice inhale TiO2 NPs, while controls receive an equivalent volume of saline. Treatment with oral GTE is initiated after TiO2 NPs inhalation and is given once daily for 4 weeks. Airway resistance and pulmonary inflammation are increased in mice exposed to TiO2 NPs. GTE treatment reduces the airway inflammation and airway resistance, and attenuates the pathological changes including lung fibrosis compared to the mice exposed to TiO2 NPs. With GTE, there are no significant increases in cytokines and immunoglobulin E (IgE) in mice exposed to TiO2 NPs. GTE inhibits matrix metalloproteinases (MMPs) and apoptotic factors induced by TiO2 NPs exposure, and these protective effects of GTE are closely related to the mitogen-activated protein kinase (MAPK) signaling pathway. CONCLUSION: GTE modulates pulmonary inflammation in mice exposed to air pollutants, suggesting that GTE may be beneficial in respiratory diseases exacerbated by such pollutants.

Impact of the Junction Adhesion Molecule-A on Asthma.

PURPOSE: Junctional adhesion molecule (JAM)-A is an immunoglobulin-like molecule that colocalizes with tight junctions (TJs) in the endothelium and epithelium. It is also found in blood leukocytes and platelets. The biological significance of JAM-A in asthma, as well as its clinical potential as a therapeutic target, are not well understood. The aim of this study was to elucidate the role of JAM-A in a mouse model of asthma, and to determine blood levels of JAM-A in asthmatic patients. MATERIALS AND METHODS: Mice sensitized and challenged with ovalbumin (OVA) or saline were used to investigate the role of JAM-A in the pathogenesis of bronchial asthma. In addition, JAM-A levels were measured in the plasma of asthmatic patients and healthy controls. The relationships between JAM-A and clinical variables in patients with asthma were also examined. RESULTS: Plasma JAM-A levels were higher in asthma patients (n=19) than in healthy controls (n=12). In asthma patients, the JAM-A levels correlated with forced expiratory volume in 1 second (FEV1%), FEV1/forced vital capacity (FVC), and the blood lymphocyte proportion. JAM-A, phospho-JNK, and phospho-ERK protein expressions in lung tissue were significantly higher in OVA/OVA mice than in control mice. In human bronchial epithelial cells treated with house dust mite extracts for 4 h, 8 h, and 24 h, the JAM-A, phospho-JNK, and phospho-ERK expressions were increased, as shown by Western blotting, while the transepithelial electrical resistance was reduced. CONCLUSION: These results suggest that JAM-A is involved in the pathogenesis of asthma, and may be a marker for asthma.

Cofilin-1 and profilin-1 expression in lung microvascular endothelial cells exposed to titanium dioxide nanoparticles.

BACKGROUND: Air pollutants exacerbate chronic airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD). However, the underlying mechanisms are yet to be determined. While a number of studies have reported adverse effects of nanoparticles on humans, little is known about their effects on the respiratory system. OBJECTIVES: To examine the protein expression in human lung microvascular endothelial cells (HMVEC-L) exposed to titanium dioxide (TiO2) nanoparticles, a common air pollutant. MATERIAL AND METHODS: A proteomics approach using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS) was used to determine the differences in protein expression at 8 h and 24 h, following the treatment of HMVEC-L with 20-µM or 40-µM TiO2 nanoparticles. RESULTS: Human lung microvascular endothelial cells treated with 20-µM TiO2 nanoparticles showed alterations of 7 protein spots, including molecules related to calcium regulation, transport, cytoskeleton, and muscle contraction. The treatment of HMVEC-L with 40-µM TiO2 nanoparticles resulted in alterations of 4 protein spots, with molecular functions related to the cytoskeleton, myosin regulation, actin modulation, as well as guanosine diphosphate (GDP) and guanosine triphosphate (GTP) regulation. To validate these results, immunohistochemical staining and western blotting analyses were performed on lung tissues collected from mice exposed to TiO2 nanoparticles. Cofilin-1 and profilin-1 were expressed in the endothelium, epithelium and inflammatory cells, and decreased in lung tissues of TiO2 nanoparticle-exposed mice compared to sham-treated controls. CONCLUSIONS: These results suggest that some of the differentially expressed proteins may play important roles in airway diseases caused by TiO2 nanoparticle exposure.

N-acetylcysteine decreases lung inflammation and fibrosis by modulating ROS and Nrf2 in mice model exposed to particulate matter.

Background and Objectives: Air pollutants can induce and incite airway diseases such as asthma. N-acetylcysteine (NAC) affects signaling pathways involved in apoptosis, angiogenesis, cell growth and arrest, redox-regulated gene expression, and the inflammatory response. However, it is not known how NAC change redox-regulated gene expression in asthma mouse model exposed to particulate matter (PM). To investigate the effects of NAC on asthma mice exposed to PM through Reactive oxygen species (ROS), nuclear factor erythroid 2-related factor 2 (Nrf2), and mucin 5 (Muc5).Methods: To investigate the effects of NAC (100 mg/kg) on redox-regulated gene expression and lung fibrosis in a mouse model of asthma exposed to PM. A mice model of asthma induced by ovalbumin (OVA) or OVA plus titanium dioxide (OVA + TiO2) was established using wild-type BALB/c female mice, and the levels of Nrf2 and mucin 5AC (Muc5ac) proteins following NAC treatment were examined by Western blotting and immunostaining. In addition, the protein levels of ROS were checked.Results: Airway hyperresponsiveness and inflammation, goblet cell hyperplasia, and lung fibrosis were higher in OVA, OVA + TiO2 mice than in control mice. NAC diminished OVA + TiO2-induced airway hyperresponsiveness and inflammation, goblet cell hyperplasia, and lung fibrosis. Levels of ROS, Nrf2, and Muc5ac protein were higher in lung tissue from OVA + TiO2 mice than that from control mice and were decreased by treatment with NAC.Conclusions: NAC reduce airway inflammation and responsiveness, goblet cell hyperplasia, and lung fibrosis by modulating ROS and Nrf2.

Recent patents in allergy and immunology: A quantitative real-time polymerase chain reaction method for diagnosing asthma and asthma exacerbation.

Background: Asthma is diagnosed based on a history of the characteristic symptoms and evidence of expiratory airflow limitation. However, asthma diagnosis using the existing tests is associated with a risk of coronavirus disease 2019 caused by severe acute respiratory syndrome coronavirus 2 spread. In this study, we developed a quantitative real-time polymerase chain reaction (qRT-PCR)-based asthma diagnosis tool. Methods: We detected nectin-4 in the plasma of patients with asthma using qRT-PCR, explored the relationship of clinical variables. Results: quantitative real-time polymerase chain reaction revealed that plasma nectin-4 mRNA levels were higher in asthmatics than controls. These results correlated with lung function. Conclusions: Those results suggest that qRT-PCR for nectin-4 may aid asthma diagnosis and monitoring.

The Impact of Environmental Pollutants on Barrier Dysfunction in Respiratory Disease.

Respiratory epithelial cells form a selective barrier between the outside environment and underlying tissues. Epithelial cells are polarized and form specialized cell-cell junctions, known as the apical junctional complex (AJC). Assembly and disassembly of the AJC regulates epithelial morphogenesis and remodeling processes. The AJC consists of tight and adherens junctions, functions as a barrier and boundary, and plays a role in signal transduction. Endothelial junction proteins play important roles in tissue integrity and vascular permeability, leukocyte extravasation, and angiogenesis. Air pollutants such as particulate matter, ozone, and biologic contaminants penetrate deep into the airways, reaching the bronchioles and alveoli before entering the bloodstream to trigger airway inflammation. Pollutants accumulating in the lungs exacerbate the symptoms of respiratory diseases, including asthma and chronic obstructive lung disease. Biological contaminants include bacteria, viruses, animal dander and cat saliva, house dust mites, cockroaches, and pollen. Allergic inflammation develops in tissues such as the lung and skin with large epithelial surface areas exposed to the environment. Barrier dysfunction in the lung allows allergens and environmental pollutants to activate the epithelium and produce cytokines that promote the induction and development of immune responses. In this article, we review the impact of environmental pollutants on the cell barrier in respiratory diseases.

Effects of Air Pollutants on Airway Diseases.

Air pollutants include toxic particles and gases emitted in large quantities from many different combustible materials. They also include particulate matter (PM) and ozone, and biological contaminants, such as viruses and bacteria, which can penetrate the human airway and reach the bloodstream, triggering airway inflammation, dysfunction, and fibrosis. Pollutants that accumulate in the lungs exacerbate symptoms of respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD). Asthma, a heterogeneous disease with complex pathological mechanisms, is characterized by particular symptoms such as shortness of breath, a tight chest, coughing, and wheezing. Patients with COPD often experience exacerbations and worsening of symptoms, which may result in hospitalization and disease progression. PM varies in terms of composition, and can include solid and liquid particles of various sizes. PM concentrations are higher in urban areas. Ozone is one of the most toxic photochemical air pollutants. In general, air pollution decreases quality of life and life expectancy. It exacerbates acute and chronic respiratory symptoms in patients with chronic airway diseases, and increases the morbidity and risk of hospitalization associated with respiratory diseases. However, the mechanisms underlying these effects remain unclear. Therefore, we reviewed the impact of air pollutants on airway diseases such as asthma and COPD, focusing on their underlying mechanisms.