Biological effect of PM10 on airway epithelium-focus on obstructive lung diseases

Interactions among tuberculosis, geographic environment and aerosols: evidence from the Kashgar region of China

Background

Aerosols can affect human health through mechanisms like inflammation, oxidative stress, immune dysregulation, and respiratory impairment. In high-pollution areas, airborne particles may promote the transmission of pathogens such as Mycobacterium tuberculosis. This study investigates the spatiotemporal distribution of tuberculosis, its association with air pollution, and potential sources in the geographically unique Kashgar region of Xinjiang, encircled by mountains and desert.

Methods

Kriging interpolation and time series observation were used to analyze spatiotemporal trends and identify hot and cold spots of tuberculosis (TB) incidence and air quality in Xinjiang from 2011 to 2023. Kruskal-Wallis and multiple comparisons were applied to assess regional differences. Meteorological clustering and trajectory analysis identified pollutant pathways and potential source areas, with hypotheses proposed for TB transmission routes.

Results

The interaction between tuberculosis, the geographic environment, and aerosols in Xinjiang reveals a consistent spatial distribution of air quality index (AQI) and TB incidence, with overlapping hotspots and cold spots. The incidence rate of tuberculosis is "n/100,000."Southern Xinjiang, shows higher TB incidence (235.31 ± 92.44) and poorer air quality (AQI: 64.19 ± 11.73) compared to Northern Xinjiang (TB: 83.82 ± 21.43, AQI: 53.90 ± 6.48). Significant regional differences in TB incidence (p < 0.0001) were confirmed, with post-hoc analyses indicating higher TB rates and worse air quality in Southern Xinjiang. Trajectory and concentration-weighted trajectory (WCWT) analysis identified dust from the Taklimakan Desert as a major contributor to PM2.5 and PM10 pollution, with values exceeding 150 μg/m3 for PM2.5 and 400 μg/m3 for PM10 in key areas like Aksu and Kashgar. The Kunlun and Tianshan mountain ranges serve as barriers that trap migrating dust, while meteorological patterns indicate that dust-laden trajectories extend further into the mountainous areas. This phenomenon exacerbates the spread of tuberculosis (TB) in the high-risk regions of southern Xinjiang.

Conclusion

The study highlights a distinct interaction between TB, the geographic environment, and aerosols in southern Xinjiang. Poor air quality and elevated TB incidence overlap, particularly in Kashgar. Here, dust from the Taklimakan Desert, trapped by the Kunlun and Tianshan mountains, intensifies PM2.5 and PM10 pollution, further contributing to TB transmission in high-risk areas.

Impact of Saharan Dust and SERPINA1 Gene Variants on Bacterial/Fungal Balance in Asthma Patients

The Canary Islands, a region with high asthma prevalence, are frequently exposed to Saharan Dust Intrusions (SDIs), as are a wide range of countries in Europe. Alpha-1 antitrypsin (SERPINA1 gene) regulates the airway's inflammatory response. This study analyzed the combined effect of SDI exposure and SERPINA1 variants on bacterial/fungal DNA concentrations in saliva and pharyngeal samples from asthmatic patients. Bacterial and fungal DNAs were quantified by qPCR in 211 asthmatic patients (GEMAS study), grouped based on their exposure to daily PM10 concentrations. Associations between SDI exposure, microbial DNA concentrations, and nine variants in SERPINA1 were tested using linear regression models adjusted for confounders. The ratio between bacterial and fungal DNA was similar in saliva and pharyngeal samples. SDI exposure for 1-3 days was enough to observe significant microbial DNA change. Increased bacterial DNA concentration was detected when SDI exposure occurred 4-10 days prior to sampling, while exposure between days 1 and 3 led to a reduction in the fungal DNA concentration. The T-allele of SERPINA1 SNV rs2854254 prevented the increase in the bacterial/fungal DNA ratio in pharyngeal samples after SDI exposure. The bacterial/fungal DNA ratio represents a potential tool to monitor changes in the microbiome of asthmatic patients.

Joint effects of temperature and humidity with PM2.5 on COPD

BACKGROUND

Particulate matter less than 2.5 microns in aerodynamic diameter (PM2.5) is a significant air pollutant known to adversely affect respiratory health and increase the incidence of chronic obstructive pulmonary disease (COPD). Furthermore, climate change exacerbates these impacts, as extreme temperatures and relative humidity (RH) levels can intensify the effects of PM2.5. This study aims to examine the joint effects of PM2.5, temperature, and RH on the risk of COPD.

METHODS

A case-control study was conducted among 1,828 participants from 2017 to 2022 (995 COPD patients and 833 controls). The radial basis function interpolation was utilized to estimate participants' individual mean and differences in PM2.5, temperature, and RH in 1-day, 7-day, and 1-month periods. Logistic regression models examined the associations of environmental exposures with the risk of COPD adjusting for confounders. Joint effects of PM2.5 by quartiles of temperature and RH were also examined.

RESULTS

We observed that a 1 µg/m3 increase in PM2.5 7-day and 1-month mean was associated with a 1.05-fold and 1.06-fold increase in OR of COPD (p < 0.05). For temperature and RH, we observed U-shaped effects on OR for COPD with optimal temperatures identified as 21.2 °C, 23.8 °C, and 23.8 °C for 1-day, 7-day, and 1-month mean temperature, respectively, and optimal RH levels identified as 73.8%, 76.7%, and 75.4% for 1-day, 7-day, and 1-month mean RH, respectively (p < 0.05). The joint effect models show that high temperatures (> 23.5 °C) and both extremely low (69.3%) and high (80.9%) RH levels generally exacerbate the effects of PM2.5 on OR for COPD, especially over longer exposure durations.

CONCLUSION

The joint effects of PM2.5, temperature, and RH on the risk of COPD underscore the importance of air pollution control and comprehensive research to mitigate COPD risk in the context of climate change.

Particulate matter and potentially toxic element content in urban ornamental plant species to assess pollutants trapping capacity

Urban environments are usually polluted by anthropogenic activities like traffic, a major source of potentially toxic elements (PTEs), and ornamental plant species may reduce contamination by trapping traffic-related air pollutants in their leaves. The purpose of this study was tested the trapping pollutant capacity of four species commonly used in green areas of Seville city (SW Spain) to better choose species in urban green planning. Composition of particulate matter (PM) obtained from foliar surfaces (sPM) and wax-included (wPM) was determined by EDX-SEM analysis in samples from different city locations. Concentration of different PTEs (Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn), by microwave induced-plasma optical emission spectroscopy (MP-AES) were also analyzed in unwashed leaves of one of the selected species (Citrus aurantium) since it is the most cultivated species in Seville. Results showed that Nerium oleander was the plant species which trapped best superficial total and coarse PM. This capacity was enhanced by the presence of a waxy-cuticle and by cuticle thickness but not by leaf hairs. The only species unable to trap fine particles was Bougainvillea glabra. The most representative sPM on leaf surfaces from all species was the largest fraction (59-75%), followed by coarse (25-37%) and fine fractions (2.2-4.4%). In the wax PM, 48% of coarse particles were found in Citrus aurantium. Particulate matter deposited on surface foliage in general did not vary seasonally, while the large fraction of wPM in summer was significantly higher than in winter. The seasonal differences also existed in the level of PTE (Cd, Fe, Ni and V) in leaves. This work indicates that the leaf traits should be taken into account to evaluate the pollutants caption capacity, especially when planning of recreational green urban areas. Particulate matter composition was different according to the pollution sources and mostly contained Al, C, Ca, Fe, K, and Mg, but potentially toxic elements such as Si, As, Cr, Cu and Zn just accounted for 0.11-1.95% of the total elemental content.

Moderate PM10 exposure increases prostate cancer: a longitudinal nationwide cohort study (2010-2020)

Introduction

Fine dust exposure has been reported to affect patients with prostate cancer, making it crucial to understand how environmental pollutants impact health. This study aimed to determine the risk of prostate cancer in South Korea associated with moderate levels of fine dust (PM10) exposure.

Methods

We analyzed data from 20,430 individuals in the National Health Insurance Sharing Service database from 2010 to 2020, comparing a new prostate cancer group (n = 4,071, 19.9%) with a non-prostate cancer group (n = 16,359, 80.1%). Using PM10 data from Air Korea's annual average air quality database, we conducted logistic regression analysis to assess the risk of prostate cancer.

Results

Our findings indicate that even moderate PM10 exposure is a risk factor for developing prostate cancer. Additionally, even at low levels of PM2.5, moderate PM10 exposure significantly impacts prostate cancer development, with lifestyle ha bits potentially lowering this risk.

Discussion

These results underscore the need for stricter environmental standards for PM10 and proactive policies to reduce public health and long-term social costs. Public awareness, including mask use and air quality management, is essential.

The impact of airborne particulate matter-based pollution on the cellular and molecular mechanisms in chronic obstructive pulmonary disease (COPD)

Inhalation of particulate matter (PM), one of the many components of air pollution, is associated with the development and exacerbation of chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD). COPD is one of the leading causes of global mortality and morbidity, with a paucity of therapeutic options and a significant contributor to global health expenditure. This review aims to provide a mechanistic understanding of the cellular and molecular pathways that lead to the development of COPD following chronic PM exposure. Our review describes how the inhalation of PM can lead to lung parenchymal destruction and cellular senescence due to chronic pulmonary inflammation and oxidative stress. Following inhalation of PM, significant increases in a range of pro-inflammatory cytokines, mediated by the nuclear factor kappa B pathway are reported. This review also highlights how the inhalation of PM can lead to deleterious chronic oxidative stress persisting in the lung post-exposure. Furthermore, our work summarises how PM inhalation can lead to airway remodelling, with increases in pro-fibrotic cytokines and collagen deposition, typical of COPD. This paper also accentuates the interconnection and possible synergism between the pathophysiological mechanisms leading to COPD. Our work emphasises the serious health consequences of PM exposure on respiratory health. Elucidation of the cellular and molecular mechanisms can provide insight into possible therapeutic options. Finally, this review should serve as a stark reminder of the need for genuine action on air pollution to decrease the associated health burden on our growing global population.

Fusarium graminearum spores disrupt gut microbiota and metabolome via the lung-gut axis in mice

Fusarium graminearum, the primary pathogen responsible for wheat Fusarium head blight, can induce pulmonary damage through its spores. However, the detailed mechanism by which these spores cause intestinal injury is not yet fully understood. This study aimed to investigate the impact of exposure to fungal spores on the intestinal microbiota using a mice model that mimics the effects of fusarium graminearum spores on the gut microbiota and its metabolic profile. The study utilized 16S rRNA sequencing and metabolomics methodologies to analyze the contents of the cecum and feces in mice. The results showed that exposure to fungal spores led to significant changes in the composition of the intestinal microbiota in mice, characterized by an increase in Akkermansia and Staphylococcus populations. A non-targeted metabolomics analysis identified 316 metabolites associated with various metabolic pathways, particularly galactose metabolism. Pre-exposure to antibiotics before fungal spore exposure resulted in a decrease in the metabolic capacity of the intestinal microbiota in mice. This research demonstrates that fusarium graminearum spores can disrupt the intestinal microbiota and metabolome via the lung-gut axis. These findings provide valuable insights into the intestinal damage caused by fungal spores and offer important support for the development of therapeutic strategies for intestinal diseases.

Autoimmune Diseases Following Environmental Disasters: A Narrative Review of the Literature

Environmental disasters are extreme environmental processes such as earthquakes, volcanic eruptions, landslides, tsunamis, floods, cyclones, storms, wildfires and droughts that are the consequences of the climate crisis due to human intervention in the environment. Their effects on human health have alarmed the global scientific community. Among them, autoimmune diseases, a heterogeneous group of disorders, have increased dramatically in many parts of the world, likely as a result of changes in our exposure to environmental factors. However, only a limited number of studies have attempted to discover and analyze the complex association between environmental disasters and autoimmune diseases. This narrative review has therefore tried to fill this gap. First of all, the activation pathways of autoimmunity after environmental disasters have been analyzed. It has also been shown that wildfires, earthquakes, desert dust storms and volcanic eruptions may damage human health and induce autoimmune responses to inhaled PM2.5, mainly through oxidative stress pathways, increased pro-inflammatory cytokines and epithelial barrier damage. In addition, it has been shown that heat stress, in addition to increasing pro-inflammatory cytokines, may also disrupt the intestinal barrier, thereby increasing its permeability to toxins and pathogens or inducing epigenetic changes. In addition, toxic volcanic elements may accelerate the progressive destruction of myelin, which may potentially trigger multiple sclerosis. The complex and diverse mechanisms by which vector-borne, water-, food-, and rodent-borne diseases that often follow environmental diseases may also trigger autoimmune responses have also been described. In addition, the association between post-disaster stress and the onset or worsening of autoimmune disease has been demonstrated. Given all of the above, the rapid restoration of post-disaster health services to mitigate the flare-up of autoimmune conditions is critical.

Impact of environmental air pollution on respiratory health and function

Environmental air pollution presents a considerable risk to global respiratory health. If critical levels are exceeded, inhaled pollutants can lead to the development of respiratory dysfunction and provoke exacerbation in those with pre-existing chronic respiratory disease. Over 90% of the global population currently reside in areas where environmental air pollution is considered excessive-with adverse effects ranging from acute airway irritation to complex immunomodulatory alterations. This narrative review provides an up-to-date perspective concerning the impact of environmental air pollution on respiratory health and function and describes the underpinning mechanisms that contribute to the development and progression of chronic respiratory disease.

Gene expression changes in mouse lung induced by subacute inhalation of PM10-rich particulate matter

INTRODUCTION

Particulate matter (PM) air pollution is associated with an increased incidence of lung diseases, but the underlying mechanisms have not been fully elucidated. In this study, a mouse model of subacute lung inflammation was employed to investigate the cellular responses and gene expression changes induced by exposure to natural ambient air pollution.

METHODS

C57BL/6J mice were exposed to road dust (primarily PM10) at 150 µg/m³ for 21 days (8 h/day) through a nose-only inhalation exposure system. Lung tissues were analyzed for the expression of proinflammatory signaling, oxidative stress, and fibrosis markers. RNA-sequencing analysis was conducted to identify differentially expressed genes (DEGs). A gene ontology over-representation analysis was performed to identify the altered genetic pathways.

RESULTS

Elevated levels of proinflammatory cytokines, including IL-1β, IL-6, and TNF-α, and an increase in phosphorylated MAPK were determined in the road dust exposure group compared to the control group. Histopathological examinations revealed more severe lung inflammation and damage in the exposed mice, including fibrosis and bronchiolar hyperplasia. Gene expression profiling identified 108 DEGs, with decreases in most except genes such as Krt15 and Reg3g. The protein-protein interaction network analysis together with text-mining identified 18 key hub genes, associated with fatty acid oxidation, lipid metabolism, and peroxisomes.

CONCLUSION

This study identified key genes, signaling pathways, and cellular responses in mouse lung affected by road dust exposure. These findings contribute to a deeper understanding of the transcriptional and cellular responses induced by subacute exposure to the PM in road dust.

New markers in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), a global healthcare and socioeconomic burden, is a multifaceted respiratory disorder that results in substantial decline in health status and life quality. Acute exacerbations of the disease contribute significantly to increased morbidity and mortality. Consequently, the identification of reliable and effective biomarkers for rapid diagnosis, prediction, and prognosis of exacerbations is imperative. In addition, biomarkers play a crucial role in monitoring responses to therapeutic interventions and exploring innovative treatment strategies. Although established markers such as CRP, fibrinogen and neutrophil count are routinely used, a universal marker is lacking. Fortunately, an increasing number of studies based on next generation analytics have explored potential biomarkers in COPD. Here we review those advances and the need for standardized validation studies in the appropriate clinical setting.

Gene Expression and Metabolome Analysis Reveals Anti-Inflammatory Impacts of 11,17diHDoPE on PM10-Induced Mouse Lung Inflammation

Oxylipins, the metabolites of polyunsaturated fatty acids, are vital in regulating cell proliferation and inflammation. Among these oxylipins, specialized pro-resolving mediators notably contribute to inflammation resolution. Previously, we showed that the specialized pro-resolving mediators isomer 11,17dihydroxy docosapentaenoic acid (11,17diHDoPE) can be synthesized in bacterial cells and exhibits anti-inflammatory effects in mammalian cells. This study investigates the in vivo impact of 11,17diHDoPE in mice exposed to particulate matter 10 (PM10). Our results indicate that 11,17diHDoPE significantly mitigates PM10-induced lung inflammation in mice, as evidenced by reduced pro-inflammatory cytokines and pulmonary inflammation-related gene expression. Metabolomic analysis reveals that 11,17diHDoPE modulates inflammation-related metabolites such as threonine, 2-keto gluconic acid, butanoic acid, and methyl oleate in lung tissues. In addition, 11,17diHDoPE upregulates the LA-derived oxylipin pathway and downregulates arachidonic acid- and docosahexaenoic acid-derived oxylipin pathways in serum. Correlation analyses between gene expression and metabolite changes suggest that 11,17diHDoPE alleviates inflammation by interfering with macrophage differentiation. These findings underscore the in vivo role of 11,17diHDoPE in reducing pulmonary inflammation, highlighting its potential as a therapeutic agent for respiratory diseases.

Impact of climate change on immune responses and barrier defense

Climate change is not just jeopardizing the health of our planet but is also increasingly affecting our immune health. There is an expanding body of evidence that climate-related exposures such as air pollution, heat, wildfires, extreme weather events, and biodiversity loss significantly disrupt the functioning of the human immune system. These exposures manifest in a broad range of stimuli, including antigens, allergens, heat stress, pollutants, microbiota changes, and other toxic substances. Such exposures pose a direct and indirect threat to our body's primary line of defense, the epithelial barrier, affecting its physical integrity and functional efficacy. Furthermore, these climate-related environmental stressors can hyperstimulate the innate immune system and influence adaptive immunity-notably, in terms of developing and preserving immune tolerance. The loss or failure of immune tolerance can instigate a wide spectrum of noncommunicable diseases such as autoimmune conditions, allergy, respiratory illnesses, metabolic diseases, obesity, and others. As new evidence unfolds, there is a need for additional research in climate change and immunology that covers diverse environments in different global settings and uses modern biologic and epidemiologic tools.

Effect of aerobic exercise and particulate matter exposure duration on the diversity of gut microbiota

Inhalation of ambient particulate matter (PM) can disrupt the gut microbiome, while exercise independently influences the gut microbiome by promoting beneficial bacteria. In this study, we analyzed changes in gut microbial diversity and composition in response to combined interventions of PM exposure and aerobic exercise, extending up to 12 weeks. This investigation was conducted using mice, categorized into five groups: control group (Con), exercise group (EXE), exercise group followed by 3-day exposure to PM (EXE + 3-day PM), particulate matter exposure (PM), and PM exposure with concurrent treadmill exercise (PME). Notably, the PM group exhibited markedly lower alpha diversity and richness compared to the Con group and our analysis of beta diversity revealed significant variations among the intervention groups. Members of the Lachnospiraceae family showed significant enhancement in the exercise intervention groups (EXE and PME) compared to the Con and PM groups. The biomarker Lactobacillus, Coriobacteraceae, and Anaerofustis were enriched in the EXE group, while Desulfovibrionaceae, Mucispirillum schaedleri, Lactococcus and Anaeroplasma were highly enriched in the PM group. Differential abundance analysis revealed that Paraprevotella, Bacteroides, and Blautia were less abundant in the 12-week PM exposure group than in the 3-day PM exposure group. Moreover, both the 3-day and 12-week PM exposure groups exhibited a reduced relative abundance of Bacteroides uniformis, SMB53, and Staphylococcus compared to non-PM exposure groups. These findings will help delineate the possible roles and associations of altered microbiota resulting from the studied interventions, paving the way for future mechanistic research.

Indication Variability of the Particulate Matter Sensors Dependent on Their Location

Particulate matter (PM) suspended in the air significantly impacts human health. Those of anthropogenic origin are particularly hazardous. Poland is one of the countries where the air quality during the heating season is the worst in Europe. Air quality in small towns and villages far from state monitoring stations is often much worse than in larger cities where they are located. Their residents inhale the air containing smoke produced mainly by coal-fired stoves. In the frame of this project, an air quality monitoring network was built. It comprises low-cost PMS7003 PM sensors and ESP8266 microcontrollers with integrated Wi-Fi communication modules. This article presents research results on the influence of the PM sensor location on their indications. It has been shown that the indications from sensors several dozen meters away from each other can differ by up to tenfold, depending on weather conditions and the source of smoke. Therefore, measurements performed by a network of sensors, even of worse quality, are much more representative than those conducted in one spot. The results also indicated the method of detecting a sudden increase in air pollutants. In the case of smokiness, the difference between the mean and median indications of the PM sensor increases even up to 400 µg/m3 over a 5 min time window. Information from this comparison suggests a sudden deterioration in air quality and can allow for quick intervention to protect people's health. This method can be used in protection systems where fast detection of anomalies is necessary.

Effect of E. cava and C. indicum Complex Extract on Phorbol 12-Myristate 13-Acetate (PMA)-Stimulated Inflammatory Response in Human Pulmonary Epithelial Cells and Particulate Matter (PM)2.5-Induced Pulmonary Inflammation in Mice

This study explores the potential of a natural composite formulation known as ED, consisting of Ecklonia cava (E. cava, family: Lessoniaceae) and Chrysanthemum indicum Linne (C. indicum, family: Asteraceae), in alleviating lung inflammation induced by fine particulate matter (PM2.5). Initial assessments confirmed that neither ED nor one of its components, dieckol, exhibited cytotoxic effects on A549 cells. Subsequently, the impact of ED and dieckol on MUC5AC gene expression in A549 cells stimulated by phorbol 12-myristate 13-acetate (PMA) was investigated, revealing promising results that demonstrated a dose-dependent inhibition of MUC5AC gene expression. The study also delves into the underlying mechanisms, demonstrating that ED and dieckol effectively suppressed the phosphorylation of mitogen-activated protein kinases (MAPKs), including JNK, ERK, and p38, which are known to be involved in the regulation of MUC5AC gene expression. In in vivo experiments using a PM2.5-induced pulmonary inflammation mouse model, the research findings showed that ED mitigated cellular accumulation in the airways, leading to a significant reduction in the total cell count in bronchoalveolar lavage fluid (BALF). Moreover, ED exhibited protective effects against PM2.5-induced pulmonary damage, characterized by reduced inflammatory cell infiltration and decreased mucus secretion in pulmonary tissues. Additionally, ED's anti-inflammatory properties were evident in its ability to decrease the levels of key inflammatory cytokines, TNF-α and IL-6, both in the serum and lung tissue of the PM2.5-induced pulmonary inflammation mouse model. These findings suggest the potential of ED as a therapeutic agent for inflammatory respiratory diseases.

Subway station dust-induced pulmonary inflammation may be due to the dysfunction of alveolar macrophages: Possible contribution of bound elements

With its increasing value as a means of public transportation, the health effects of the air in subway stations have attracted public concern. In the current study, we investigated the pulmonary toxicity of dust collected from an air purifier installed on the platform of the busiest subway station in Seoul. We found that the dust contained various elements which are attributable to the facilities and equipment used to operate the subway system. Particularly, iron (Fe), chromium (Cr), zirconium (Zr), barium (Ba), and molybdenum (Mo) levels were more notable in comparison with those in dust collected from the ventilation chamber of a subway station. To explore the health effects of inhaled dust, we first instilled via the trachea in ICR mice for 13 weeks. The total number of pulmonary macrophages increased significantly with the dose, accompanying hematological changes. Dust-laden alveolar macrophages and inflammatory cells accumulated in the perivascular regions in the lungs of the treated mice, and pulmonary levels of CXCL-1, TNF-α, and TGF-β increased clearly compared with the control. The CCR5 and CD54 level expressed on BAL cell membranes was also enhanced following exposure to dust, whereas the CXCR2 level tended to decrease in the same samples. In addition, we treated the dust to alveolar macrophages (known as dust cells), lysosomal and mitochondrial function decreased, accompanied by cell death, and NO production was rapidly elevated with concentration. Moreover, the expression of autophagy- (p62) and anti-oxidant (SOD-2)-related proteins increased, and the expression of inflammation-related genes was dramatically up-regulated in the dust-treated cells. Therefore, we suggest that dysfunction of alveolar macrophages may importantly contribute to dust-induced inflammatory responses and that the exposure concentrations of Cr, Fe, Mo, Zr, and Ba should be considered carefully when assessing the health risks associated with subway dust. We also hypothesize that the bound elements may contribute to dust-induced macrophage dysfunction by inhibiting viability.

Air pollution induces Staphylococcus aureus USA300 respiratory tract colonization mediated by specific bacterial genetic responses involving the global virulence gene regulators Agr and Sae

Exposure to particulate matter (PM), a major component of air pollution, is associated with exacerbation of chronic respiratory disease, and infectious diseases such as community-acquired pneumonia. Although PM can cause adverse health effects through direct damage to host cells, our previous study showed that PM can also impact bacterial behaviour by promoting in vivo colonization. In this study we describe the genetic mechanisms involved in the bacterial response to exposure to black carbon (BC), a constituent of PM found in most sources of air pollution. We show that Staphylococcus aureus strain USA300 LAC grown in BC prior to inoculation showed increased murine respiratory tract colonization and pulmonary invasion in vivo, as well as adhesion and invasion of human epithelial cells in vitro. Global transcriptional analysis showed that BC has a widespread effect on S. aureus transcriptional responses, altering the regulation of the major virulence gene regulators Sae and Agr and causing increased expression of genes encoding toxins, proteases and immune evasion factors. Together these data describe a previously unrecognized causative mechanism of air pollution-associated infection, in that exposure to BC can increase bacterial colonization and virulence factor expression by acting directly on the bacterium rather than via the host.

Particulate matter in COPD pathogenesis: an overview

Chronic obstructive pulmonary disease (COPD) is a progressive lung disorder with substantial patient burden and leading cause of death globally. Cigarette smoke remains to be the most recognised causative factor behind COPD pathogenesis. Given the alarming increase in prevalence of COPD amongst non-smokers in recent past, a potential role of air pollution particularly particulate matter (PM) in COPD development has gained much attention of the scientists. Indeed, several epidemiological studies indicate strong correlation between airborne PM and COPD incidence/exacerbations. PM-induced oxidative stress seems to be the major player in orchestrating COPD inflammatory cycle but the exact molecular mechanism(s) behind such a process are still poorly understood. This may be due to the complexity of multiple molecular pathways involved. Oxidative stress-linked mitochondrial dysfunction and autophagy have also gained importance and have been the focus of recent studies regarding COPD pathogenesis. Accordingly, the present review is aimed at understanding the key molecular players behind PM-mediated COPD pathogenesis through analysis of various experimental studies supported by epidemiological data to identify relevant preventive/therapeutic targets in the area.

Particulate Matter Exacerbates the Death of Dopaminergic Neurons in Parkinson's Disease through an Inflammatory Response

Particulate matter (PM), a component of air pollution, has been epidemiologically associated with a variety of diseases. Recent reports reveal that PM has detrimental effects on the brain. In this study, we aimed to investigate the biological effects of ambient particles on the neurodegenerative disease Parkinson’s disease (PD). We exposed mice to coarse particles (PM₁₀: 2.5–10 μm) for short (5 days) and long (8 weeks) durations via intratracheal instillation. Long-term PM₁₀ exposure exacerbated motor impairment and dopaminergic neuron death in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse models. Short-term PM₁₀ exposure resulted in both pulmonary and systemic inflammatory responses in mice. We further investigated the mechanism underlying PM₁₀-induced neurotoxicity in cocultures of lung LA-4 epithelial cells and RAW264.7 macrophages. PM₁₀ treatment elicited a dramatic increase in proinflammatory mediators in LA-4/RAW264.7 coculture. Treating BV2 microglial cells with PM₁₀-treated conditioned medium induced microglial activation. Furthermore, 1-methyl-4-phenylpyridinium (MPP⁺) treatment caused notable cell death in N2A neurons cocultured with activated BV2 cells in PM₁₀-conditioned medium. Altogether, our results demonstrated that PM₁₀ plays a role in the neurodegeneration associated with PD. Thus, the impact of PM₁₀ on neurodegeneration could be related to detrimental air pollution-induced systemic effects on the brain.

Ameliorative Effect of Citrus junos Tanaka Waste (By-Product) Water Extract on Particulate Matter 10-Induced Lung Damage

Citrus junos Tanaka (CJ)-related products are well-accepted by consumers worldwide; thus, they generate huge amounts of waste (peel, pulp, and seed) through CJ processing. Although some CJ by-products (CJBs) are recycled, their use is limited owing to the limited understanding of their nutritional and economic value. The exposure to particulate matter (PM) increases the risk of respiratory diseases. In this study, we investigated the ameliorative effects of CJB extracts (100, 200 mg/kg/day, 7 days) on PM10-induced (10 mg/kg, intranasal, 6 h) lung damage in BALB/c mice. Cell type-specific signaling pathways are examined using the A549 (PM10, 200 μg/mL, 6 h) and RAW264.7 (LPS, 100 ng/mL, 6 h) cell lines. The CJB extracts significantly attenuated PM10-induced pulmonary damage and inflammatory cell infiltration in a mouse model. The essential protein markers in inflammatory signaling pathways, such as AKT, ERK, JNK, and NF-κB for PM10-induced phosphorylation, were dramatically reduced by CJB extract treatment in both the mouse and cell models. Furthermore, the CJB extracts reduced the production of reactive oxygen species and nitric oxide in a dose-dependent manner in the cells. Comprehensively, the CJB extracts were effective in reducing PM10-induced lung injuries by suppressing pulmonary inflammation, potentially due to their anti-inflammatory and antioxidant properties.

Investigation on the mechanisms of biochanin A alleviate PM10-induced acute pulmonary cell injury

Epidemiological studies have shown that the elevated concentration of particulate matter with aerodynamic diameter less than 10 µm (PM10) is closely related to the increased risk of heart and lung diseases in the population. Natural isoflavone compound biochanin A (BCA) has anti-inflammatory and antioxidant activities, and has efficacy in alleviating lung injury. The objective of this study was to investigate the inhibitory effect of BCA on PM10 induced acute human bronchial epithelial cells injury. The results showed that PM10 decreased intracellular catalase level to 1.19 ± 0.01 nmol/min/mg prot and induce a surge of reactive oxygen species (ROS). It also increased lactate dehydrogenase (LDH) activity by 428.89% and caused the lipid peroxidation phenomenon. PM10 exposure also upregulates the expression of inflammatory cytokines and mediators. However, BCA could interfere with the above changes caused by PM10, inhibit the LDH level to 8.22 ± 0.03 u/mL, and show anti-inflammatory and antioxidant activities. In addition, the phosphatidylinositol 3-kimase (PI3K) /protein kinase B (PKB/Akt) is a key signal pathway in response to PM10 exposure. In this study, PI3K/Akt signaling pathway is seriously affected by PM10 exposure. PI3K/Akt signaling pathway, PI3K, AKT, tensin homolog deleted on chromosome 10 (PTEN), mechanistic target of rapamycin (mTOR) and p53 protein were all inhibited by PM10 exposure, and PI3K/Akt signaling pathway was inactivated. BCA exert anti-damage function by regulating the activation process of PI3K protein, intervening the regulation process of PI3K/Akt by PTEN, and intervening the expression and phosphorylation of downstream Akt protein.