Interrupting Effect of Social Distancing on Ischemic Heart Disease, Asthma, Stroke, and Suicide Attempt Patients by PM2.5 Exposure

PURPOSE

This study aimed to examine the interrupting effect of social distancing (SD) on emergency department (ED) patients with ischemic heart disease (IHD), stroke, asthma, and suicide attempts by PM2.5 exposure in eight Korean megacities from 2017 to 2020.

MATERIALS AND METHODS

The study used National Emergency Department Information System and AirKorea data. A total of 469014 patients visited EDs from 2017 to 2020. Interrupted time series analysis was employed to examine changes in the level and slope of the time series, relative risk, and confidence intervals (CIs) by PM2.5 exposure. The SD level was added to the sensitivity analysis.

RESULTS

The interrupted time series analysis demonstrated a significant increase in the ratio of relative risk (RRR) of IHD patients in Seoul (RRR=1.004, 95% CI: 1.001, 1.006) and Busan (RRR=1.007, 95% CI: 1.002, 1.012) post-SD. Regarding stroke, only patients in Seoul exhibited a significant decrease post-SD (RRR=0.995, 95% CI: 0.991, 0.999). No significant changes were observed for asthma in any of the cities. In the case of suicide attempts, Ulsan demonstrated substantial pre-SD (RR=0.827, 95% CI: 0.732, 0.935) and post-SD (RRR=1.200, 95% CI: 1.057, 1.362) differences.

CONCLUSION

While the interrupting effect of SD was not as pronounced as anticipated, this study did validate the effectiveness of SD in modifying health behaviors and minimizing avoidable visits to EDs in addition to curtailing the occurrence of infectious diseases.

Protective Effect of Fermented Sea Tangle Extract on Skin Cell Damage Caused by Particulate Matter

The skin is directly exposed to atmospheric pollutants, especially particulate matter 2.5 (PM2.5) in the air, which poses significant harm to skin health. However, limited research has been performed to identify molecules that can confer resistance to such substances. Herein, we analyzed the effect of fermented sea tangle (FST) extract on PM2.5-induced human HaCaT keratinocyte damage. Results showed that FST extract, at concentrations less than 800 μg/mL, exhibited non-significant toxicity to cells and concentration-dependent inhibition of PM2.5-induced reactive oxygen species (ROS) production. PM2.5 induced oxidative stress by stimulating ROS, resulting in DNA damage, lipid peroxidation, and protein carbonylation, which were inhibited by the FST extract. FST extract significantly suppressed the increase in calcium level and apoptosis caused by PM2.5 treatment and significantly restored the reduced cell viability. Mitochondrial membrane depolarization occurred due to PM2.5 treatment, however, FST extract recovered mitochondrial membrane polarization. PM2.5 inhibited the expression of the anti-apoptotic protein Bcl-2, and induced the expression of pro-apoptotic proteins Bax and Bim, the apoptosis initiator caspase-9, as well as the executor caspase-3, however, FST extract effectively protected the changes in the levels of these proteins caused by PM2.5. Interestingly, pan-caspase inhibitor Z-VAD-FMK treatment enhanced the anti-apoptotic effect of FST extract in PM2.5-treated cells. Our results indicate that FST extract prevents PM2.5-induced cell damage via inhibition of mitochondria-mediated apoptosis in human keratinocytes. Accordingly, FST extract could be included in skin care products to protect cells against the harmful effects of PM2.5.

Causal relationship between particulate matter 2.5 and diabetes: two sample Mendelian randomization

Backgrounds

Many studies have shown particulate matter has emerged as one of the major environmental risk factors for diabetes; however, studies on the causal relationship between particulate matter 2.5 (PM2.5) and diabetes based on genetic approaches are scarce. The study estimated the causal relationship between diabetes and PM2.5 using two sample mendelian randomization (TSMR).

Methods

We collected genetic data from European ancestry publicly available genome wide association studies (GWAS) summary data through the MR-BASE repository. The IEU GWAS information output PM2.5 from the Single nucleotide polymorphisms (SNPs) GWAS pipeline using pheasant-derived variables (Consortium = MRC-IEU, sample size: 423,796). The annual relationship of PM2.5 (2010) were modeled for each address using a Land Use Regression model developed as part of the European Study of Cohorts for Air Pollution Effects. Diabetes GWAS information (Consortium = MRC-IEU, sample size: 461,578) were used, and the genetic variants were used as the instrumental variables (IVs). We performed three representative Mendelian Randomization (MR) methods: Inverse Variance Weighted regression (IVW), Egger, and weighted median for causal relationship using genetic variants. Furthermore, we used a novel method called MR Mixture to identify outlier SNPs.

Results

From the IVW method, we revealed the causal relationship between PM2.5 and diabetes (Odds ratio [OR]: 1.041, 95% CI: 1.008-1.076, P = 0.016), and the finding was substantiated by the absence of any directional horizontal pleiotropy through MR-Egger regression (β = 0.016, P = 0.687). From the IVW fixed-effect method (i.e., one of the MR machine learning mixture methods), we excluded outlier SNP (rs1537371) and showed the best predictive model (AUC = 0.72) with a causal relationship between PM2.5 and diabetes (OR: 1.028, 95% CI: 1.006-1.049, P = 0.012).

Conclusion

We identified the hypothesis that there is a causal relationship between PM2.5 and diabetes in the European population, using MR methods.

Melatonin Ameliorates Apoptosis of A549 Cells Exposed to Chicken House PM2.5: A Novel Insight in Poultry Production

The particulate matter 2.5 (PM_2.5) from the chicken production system can cause lung injury and reduce productivity through prolonged breath as it attaches large amounts of harmful substances and microbes. Melatonin has acted to regulate physiological and metabolic disorders and improve growth performance during poultry production. This research would investigate the apoptosis caused by chicken house PM_2.5 on lung pulmonary epithelial cells and the protective action of melatonin. Here, the basal epithelial cells of human lung adenocarcinoma (A549 cells) were subjected to PM_2.5 from the broiler breeding house to investigate the apoptosis induced by PM_2.5 as well as the alleviation of melatonin. The apoptosis was aggravated by PM_2.5 (12.5 and 25 μg/mL) substantially, and the expression of Bcl-2, Bad, Bax, PERK, and CHOP increased dramatically after PM_2.5 treatment. Additionally, the up-regulation of cleaved caspase-9 and cleaved caspase-3 as well as endoplasmic reticulum stress (ERS)-related proteins, including ATF6 and CHOP, was observed due to PM_2.5 exposure. It is worth noting that melatonin could support A549 cells' survival, in which reduced expression of Bax, Bad, cleaved caspase-3, and cleaved caspase-9 appeared. Concurrently, the level of malondialdehyde (MDA) was down-regulated and enhanced the intracellular content of total superoxide dismutase (T-SOD) and catalase (CAT) after treatment by PM_2.5 together with melatonin. Collectively, our study underlined that melatonin exerted an anti-apoptotic action on A549 cells by strengthening their antioxidant capacity.

3-Bromo-4,5-dihydroxybenzaldehyde Protects Keratinocytes from Particulate Matter 2.5-Induced Damages

Cellular senescence can be activated by several stimuli, including ultraviolet radiation and air pollutants. This study aimed to evaluate the protective effect of marine algae compound 3-bromo-4,5-dihydroxybenzaldehyde (3-BDB) on particulate matter 2.5 (PM_2.5)-induced skin cell damage in vitro and in vivo. The human HaCaT keratinocyte was pre-treated with 3-BDB and then with PM_2.5. PM_2.5-induced reactive oxygen species (ROS) generation, lipid peroxidation, mitochondrial dysfunction, DNA damage, cell cycle arrest, apoptotic protein expression, and cellular senescence were measured using confocal microscopy, flow cytometry, and Western blot. The present study exhibited PM_2.5-generated ROS, DNA damage, inflammation, and senescence. However, 3-BDB ameliorated PM_2.5-induced ROS generation, mitochondria dysfunction, and DNA damage. Furthermore, 3-BDB reversed the PM_2.5-induced cell cycle arrest and apoptosis, reduced cellular inflammation, and mitigated cellular senescence in vitro and in vivo. Moreover, the mitogen-activated protein kinase signaling pathway and activator protein 1 activated by PM_2.5 were inhibited by 3-BDB. Thus, 3-BDB suppressed skin damage induced by PM_2.5.

Exogenous 8-Hydroxydeoxyguanosine Attenuates PM2.5-Induced Inflammation in Human Bronchial Epithelial Cells by Decreasing NLRP3 Inflammasome Activation

Particulate matter 2.5 (PM_2.5) induces lung injury by increasing the generation of reactive oxygen species (ROS) and inflammation. ROS aggravates NLRP3 inflammasome activation, which activates caspase-1, IL-1β, and IL-18 and induces pyroptosis; these factors propagate inflammation. In contrast, treatment with exogenous 8-hydroxydeoxyguanosine (8-OHdG) decreases RAC1 activity and eventually decreases dinucleotide phosphate oxidase (NOX) and ROS generation. To establish modalities that would mitigate PM_2.5-induced lung injury, we evaluated whether 8-OHdG decreased PM_2.5-induced ROS generation and NLRP3 inflammasome activation in BEAS-2B cells. CCK-8 and lactate dehydrogenase assays were used to determine the treatment concentration. Fluorescence intensity, Western blotting, enzyme-linked immunosorbent assay, and immunoblotting assays were also performed. Treatment with 80 μg/mL PM_2.5 increased ROS generation, RAC1 activity, NOX1 expression, NLRP3 inflammasome (NLRP3, ASC, and caspase-1) activity, and IL-1β and IL-18 levels in cells; treatment with 10 μg/mL 8-OHdG significantly attenuated these effects. Furthermore, similar results, such as reduced expression of NOX1, NLRP3, ASC, and caspase-1, were observed in PM_2.5-treated BEAS-2B cells when treated with an RAC1 inhibitor. These results show that 8-OHdG mitigates ROS generation and NLRP3 inflammation by inhibiting RAC1 activity and NOX1 expression in respiratory cells exposed to PM_2.5.

The Effects and Pathogenesis of PM2.5 and Its Components on Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD), a heterogeneous disease, is the leading cause of death worldwide. In recent years, air pollution, especially particulate matter (PM), has been widely studied as a contributing factor to COPD. As an essential component of PM, PM2.5 is associated with COPD prevalence, morbidity, and acute exacerbations. However, the specific pathogenic mechanisms were still unclear and deserve further research. The diversity and complexity of PM2.5 components make it challenging to get its accurate effects and mechanisms for COPD. It has been determined that the most toxic PM2.5 components are metals, polycyclic aromatic hydrocarbons (PAHs), carbonaceous particles (CPs), and other organic compounds. PM2.5-induced cytokine release and oxidative stress are the main mechanisms reported leading to COPD. Nonnegligibly, the microorganism in PM 2.5 may directly cause mononuclear inflammation or break the microorganism balance contributing to the development and exacerbation of COPD. This review focuses on the pathophysiology and consequences of PM2.5 and its components on COPD.

Effect of Acute PM2.5 Exposure on Lung Function in Children: A Systematic Review and Meta-Analysis

Objective

The objective of this study was to conduct a systematic review and meta-analysis to identify the adverse effects of acute PM2.5 exposure on lung function in children.

Design

Systematic review and meta-analysis. Setting, participants and measures: Eligible studies analyzing PM2.5 level and lung function in children were screened out. Effect estimates of PM2.5 measurements were quantified using random effect models. Heterogeneity was investigated with Q-test and I² statistics. We also conducted meta-regression and sensitivity analysis to explore the sources of heterogeneity, such as different countries and asthmatic status. Subgroup analyses were conducted to determine the effects of acute PM2.5 exposure on children of different asthmatic status and in different countries.

Results

A total of 11 studies with 4314 participants from Brazil, China and Japan were included finally. A 10 μg/m³ increase of PM2.5 was associated with a 1.74L/min (95% CI: -2.68, -0.90) decrease in peak expiratory flow (PEF). Since the asthmatic status and country could partly explain the heterogeneity, we conducted the subgroup analysis. Children with severe asthma were more susceptible to PM2.5 exposure (-3.11 L/min per 10 μg/m³ increase, 95% CI -4.54, -1.67) than healthy children (-1.61 L/min per 10 μg/m³ increase, 95% CI -2.34, -0.91). In the children of China, PEF decreased by 1.54 L/min (95% CI -2.33, -0.75) with a 10 μg/m³ increase in PM2.5 exposure. In the children of Japan, PEF decreased by 2.65 L/min (95% CI -3.82, -1.48) with a 10 μg/m³ increase of PM2.5 exposure. In contrast, no statistic association was found between every 10 μg/m³ increase of PM2.5 and lung function in children of Brazil (-0.38 L/min, 95% CI -0.91, 0.15).

Conclusion

Our results demonstrated that the acute PM2.5 exposure exerted adverse impacts on children's lung function, and children with severe asthma were more susceptible to the increase of PM2.5 exposure. The impacts of acute PM2.5 exposure varied across different countries.

Transcriptome Analysis of Particulate Matter 2.5-Induced Abnormal Effects on Human Sebocytes

Particulate matter 2.5 (PM2.5), an atmospheric pollutant with an aerodynamic diameter of <2.5 μm, can cause serious human health problems, including skin damage. Since sebocytes are involved in the regulation of skin homeostasis, it is necessary to study the effects of PM2.5 on sebocytes. We examined the role of PM2.5 via the identification of differentially expressed genes, functional enrichment and canonical pathway analysis, upstream regulator analysis, and disease and biological function analysis through mRNA sequencing. Xenobiotic and lipid metabolism, inflammation, oxidative stress, and cell barrier damage-related pathways were enriched; additionally, PM2.5 altered steroid hormone biosynthesis and retinol metabolism-related pathways. Consequently, PM2.5 increased lipid synthesis, lipid peroxidation, inflammatory cytokine expression, and oxidative stress and altered the lipid composition and expression of factors that affect cell barriers. Furthermore, PM2.5 altered the activity of sterol regulatory element binding proteins, mitogen-activated protein kinases, transforming growth factor beta-SMAD, and forkhead box O3-mediated pathways. We also suggest that the alterations in retinol and estrogen metabolism by PM2.5 are related to the damage. These results were validated using the HairSkin® model. Thus, our results provide evidence of the harmful effects of PM2.5 on sebocytes as well as new targets for alleviating the skin damage it causes.

Risk of maternal exposure to mixed air pollutants during pregnancy for congenital heart diseases in offspring

OBJECTIVE

To explore the risk of maternal exposure to mixed air pollutants of particulate matter 1 (PM ₁), particulate matter 2.5 (PM _2.5), particulate matter 10 (PM ₁₀) and NO ₂ for congenital heart disease (CHD) in offspring, and to estimate the ranked weights of the above pollutants.

METHODS

6038 CHD patients and 5227 healthy controls from 40 medical institutions in 21 cities in Guangdong Registry of Congenital Heart Disease (GRCHD) from 2007 to 2016 were included. Logistic regression model was used to estimate the effect of maternal exposure to a single air pollutant on the occurrence of CHD in offspring. Spearman correlation coefficient was used to analyze the correlation between various pollutants, and Quantile g-computation was used to evaluate the joint effects of mixed exposure of air pollutants on CHD and the weights of various pollutants.

RESULTS

The exposure levels of PM ₁, PM _2.5, PM ₁₀ and NO ₂ in the CHD group were significantly higher than those in the control group (all P<0.01). The correlation coefficients among PM ₁, PM _2.5, PM ₁₀ and NO ₂ were greater than 0.80. PM ₁, PM _2.5, PM ₁₀ and NO ₂ exposure were associated with a significantly increased risk of CHD in offspring. Mixed exposure of these closely correlated pollutants presented much stronger effect on CHD than exposure of any single pollutants. There was a monotonic increasing relationship between mixed exposure and CHD risk. For each quantile increase in mixed exposure, the risk of CHD increased by 47% ( OR=1.47, 95% CI: 1.34-1.61). Mixed exposure had greater effect on CHD in the early pregnancy compared with middle and late pregnancy, but the greatest effect was the exposure in the whole pregnancy. The weight of PM ₁₀ is the highest in the mixed exposure (81.3%).

CONCLUSIONS

Maternal exposure to the mixture of air pollutants during pregnancy increases the risk of CHD in offspring, and the effect is much stronger than that of single exposure of various pollutants. PM ₁₀ has the largest weights and the strongest effect in the mixed exposure.

The Protective Effect of Oral Application of Corni Fructus on the Disorders of the Cornea, Conjunctiva, Lacrimal Gland and Retina by Topical Particulate Matter 2.5

Particulate matter 2.5 (PM_2.5) may aggravate dry eye disease (DED). Corni Fructus (CF), which is fruit of Cornus officinalis Sieb. et Zucc., has been reported to have various beneficial pharmacological effects, whereas the effect of CF on the eye is still unknown. Therefore, in this study, we investigated the effect of oral administration of water extract of CF (CFW) on the eye, hematology, and biochemistry in a DED model induced by topical exposure to PM_2.5. Furthermore, the efficacy of CFW compared with cyclosporine (CsA), an anti-inflammatory agent, and lutein, the posterior eye-protective agent. Sprague-Dawley rats were topically administered 5 mg/mL PM_2.5 in both eyes four times daily for 14 days. During the same period, CFW (200 mg/kg and 400 mg/kg) and lutein (4.1 mg/kg) were orally administered once a day. All eyes of rats in the 0.05% cyclosporine A (CsA)-treated group were topically exposed to 20 μL of CsA, twice daily for 14 days. Oral administration of CFW attenuated the PM_2.5-induced reduction of tear secretion and corneal epithelial damage. In addition, CFW protected against goblet cell loss in conjunctiva and overexpression of inflammatory factors in the lacrimal gland following topical exposure to PM_2.5. Furthermore, CFW markedly prevented PM_2.5-induced ganglion cell loss and recovered the thickness of inner plexiform layer. Meanwhile, CFW treatment decreased the levels of total cholesterol and low-density lipoprotein cholesterol in serum induced by PM_2.5. Importantly, the efficacy of CFW was superior or similar to that of CsA and lutein. Taken together, oral administration of CFW may have protective effects against PM_2.5-induced DED symptoms via stabilization of the tear film and suppression of inflammation. Furthermore, CFW may in part contribute to improving retinal function and lipid metabolism disorder.

Particulate matter 2.5 triggers airway inflammation and bronchial hyperresponsiveness in mice by activating the SIRT2-p65 pathway

Exposure to particulate matter 2.5 (PM2.5) potentially triggers airway inflammation by activating nuclear factor-κB (NF-κB). Sirtuin 2 (SIRT2) is a key modulator in inflammation. However, the function and specific mechanisms of SIRT2 in PM2.5-induced airway inflammation are largely understudied. Therefore, this work investigated the mechanisms of SIRT2 in regulating the phosphorylation and acetylation of p65 influenced by PM2.5-induced airway inflammation and bronchial hyperresponsiveness. Results revealed that PM2.5 exposure lowered the expression and activity of SIRT2 in bronchial tissues. Subsequently, SIRT2 impairment promoted the phosphorylation and acetylation of p65 and activated the NF-κB signaling pathway. The activation of p65 triggered airway inflammation, increment of mucus secretion by goblet cells, and acceleration of tracheal stenosis. Meanwhile, p65 phosphorylation and acetylation, airway inflammation, and bronchial hyperresponsiveness were deteriorated in SIRT2 knockout mice exposed to PM2.5. Triptolide (a specific p65 inhibitor) reversed p65 activation and ameliorated PM2.5-induced airway inflammation and bronchial hyperresponsiveness. Our findings provide novel insights into the molecular mechanisms underlying the toxicity of PM2.5 exposure. Triptolide inhibition of p65 phosphorylation and acetylation could be an effective therapeutic approach in averting PM2.5-induced airway inflammation and bronchial hyperresponsiveness.

Diesel Exhaust Particulates Induce Neutrophilic Lung Inflammation by Modulating Endoplasmic Reticulum Stress-Mediated CXCL1/KC Expression in Alveolar Macrophages

Diesel exhaust particulates (DEP) have adverse effects on the respiratory system. Endoplasmic reticulum (ER) abnormalities contribute to lung inflammation. However, the relationship between DEP exposure and ER stress in the respiratory immune system and especially the alveolar macrophages (AM) is poorly understood. Here, we examined ER stress and inflammatory responses using both in vivo and in vitro study. For in vivo study, mice were intratracheally instilled with 25, 50, and 100 μg DEP and in vitro AM were stimulated with DEP at 1, 2, and 3 mg/mL. DEP increased lung weight and the number of inflammatory cells, especially neutrophils, and inflammatory cytokines in bronchoalveolar lavage fluid of mice. DEP also increased the number of DEP-pigmented AM and ER stress markers including bound immunoglobulin protein (BiP) and CCAAT/enhancer binding protein-homologous protein (CHOP) were upregulated in the lungs of DEP-treated mice. In an in vitro study, DEP caused cell damage, increased intracellular reactive oxygen species, and upregulated inflammatory genes and ER stress-related BiP, CHOP, splicing X-box binding protein 1, and activating transcription factor 4 expressions in AM. Furthermore, DEP released the C-X-C Motif Chemokine Ligand 1 (CXCL1/KC) in AM. In conclusion, DEP may contribute to neutrophilic lung inflammation pathogenesis by modulating ER stress-mediated CXCL1/KC expression in AM.

Particulate Matter 2.5 Induced Developmental Cardiotoxicity in Chicken Embryo and Hatchling

Particulate matter poses health risk to developing organisms. To investigate particulate matters with a diameter smaller than 2.5 um (PM2.5)-induced developmental cardiotoxicity, fertile chicken eggs were exposed to PM2.5 via air cell injection at doses of 0.05, 0.2, 0.5, 2, and 5 mg/egg kg. Morphological changes in the embryonic day four (ED4) and hatchling hearts were assessed with histological techniques. Heart rates of hatchling chickens were measured with electrocardiography. The protein expression levels of nuclear factor kappa-light-chain-enhancer of activated B cells p65 (NF-kb p65), inducible nitric oxide synthase (iNOS), and matrix metallopeptidase 9 (MMP9) were assessed with immunohistochemistry or western blotting in hatchling hearts. PM2.5 exposure elevated areas of heart in ED4 embryo, increased heart rate, and thickened right ventricular wall thickness in hatchling chickens. Immunohistochemistry revealed enhanced NF-kb p65 expression in hatchling hearts. Western blotting results indicated that both iNOS and MMP9 expression were enhanced by lower doses of PM2.5 exposure (0.2 and 0.5 mg/kg) but not 2 mg/kg. In summary, developmental exposure to PM2.5 induced developmental cardiotoxicity in chicken embryo and hatchling chickens, which is associated with NF-kb p65, iNOS, and MMP9.

In vitro and in vivo Evaluation of the Efficacy and Safety of Powder Hydroxypropylmethylcellulose as Nasal Mucosal Barrier

Introduction

Insufflation of powder hydroxypropylmethylcellulose (pHPMC) in the nose has been proven an effective barrier in subjects with rhinitis in many clinical studies. We conducted additionally in vitro and in vivo experiments to address outstanding efficacy and safety issues.

Methods

We used an experimental setup to demonstrate the inhibition of the diffusion of allergen extracts (house dust mite, Japanese cedar, Ragweed, Timothy grass) and pollutants (particulate matter 2.5 µm, PM2.5). Safety of pHPMC when insufflated in the airways of rats was assessed in 24 animals which were sacrificed; tissue sections from lungs, brain and liver were made 1, 24 and 48 hrs after pHPMC inhalation and compared to those of control animals.

Results

pHPMC acted as an effective barrier to diffusion of both the liquid allergen extracts and of PM2.5 into the agar covered slides: the quantities of the other tested allergens ranged between <0.5% and 14% of the quantities diffused in the void slides after 6 hrs. The quantity of PM2.5 penetrating the agar was reduced by 94%. Histological photomicrographs did not reveal any evidence of inflammation at 1, 24 and 48 hrs after pHPMC insufflation.

Conclusion

Use of pHPMC should be viewed as a barrier enforcing measure against inhalatory ambient intruders.

Effect of PM2.5 on MicroRNA Expression and Function in Nasal Mucosa of Rats With Allergic Rhinitis

BACKGROUND

Particulate matter 2.5 (PM2.5) refers to particulate matter with aerodynamic equivalent diameter less than or equal to 2.5 µm, which is an important component of air pollution. PM2.5 aggravates allergic rhinitis (AR) and promotes AR nasal mucosa inflammation. Therefore, the influence of PM2.5 inhalation exposure on microRNA (miRNA) expression profiles and function in the nasal mucosa of AR rats was investigated.

METHODS

Female Sprague Dawley rats were distributed randomly to 2 groups: AR model PM2.5 exposure group (ARE group) and AR model PM2.5-unexposed control group (ARC group). The rats of ARE group were made to inhale PM2.5 at a concentration of 200 µg/m³, 3 h/day, for 30 days. miRNA expression profiles of the nasal mucosa from both groups were determined using an miRNA gene chip and were verified by quantitative real-time PCR (qRT-PCR). Gene function enrichment analysis was performed using bioinformatics analysis.

RESULTS

The ARE group revealed 20 significantly differentially expressed miRNAs, including 4 upregulated and 16 downregulated miRNAs (fold change > 1.5 or < 0.66, P < .05). Of these, 9 selected miRNAs were verified by qRT-PCR, and the results of 8 miRNAs were in accordance with the miRNA gene chip results, with highly positive correlation (r = .8583, P = .0031). Numerous target genes of differentially expressed miRNAs were functionally enriched in high-affinity immunoglobulin E receptor signaling, ErbB signaling, mucin O-glycans biosynthesis, transforming growth factor β signaling, mitogen-activated protein kinase signal transduction, phosphatidylinositol signaling, mucopolysaccharide biosynthesis, mammalian target of rapamycin signaling, T cell receptor signaling, Wnt signaling, chemokine signal transduction, and natural killer cell-mediated cytotoxicity pathways.

CONCLUSIONS

PM2.5 causes significant changes in miRNA expression in the nasal mucosa of AR rats. miRNA plays an important role in regulating PM2.5 effects in AR rat biological behavior and mucosal inflammation. This study provides a theoretical basis for the prevention and treatment of AR from the effects of environmental pollution on the gene regulation mechanism.

PM2.5 induces apoptosis, oxidative stress injury and melanin metabolic disorder in human melanocytes

Recent growing evidence suggested that particulate matter 2.5 (PM2.5) has strong toxic effects on skin systems. However, the possible effects and the mechanisms of PM2.5 on vitiligo remain poorly understood. Therefore, the present study aimed to further investigate the effects and possible mechanisms of PM2.5 on vitiligo. Human keratinocytes (HaCaT cells) and human melanocytes (PIG1 cells and PIG3V cells) were exposed to PM2.5 (0-200 µg/ml) for 24 h. The cell viability of the three cell lines was measured by a Cell Counting Kit-8 assay. The secretions of stem cell factor (SCF) and basic fibroblast growth factor (bFGF) in HaCaT cells were evaluated by ELISA. The melanin contents, cellular tyrosinase activity, apoptosis, cell migration, malondialdehyde (MDA) contents, superoxide dismutase (SOD) levels, glutathione peroxidase (GSH-Px) levels and related protein expressions in PIG1 cells and PIG3V cells were evaluated by a NaOH assay, DOPA assay, Annexin V-FITC/Propidium Iodide staining, MDA assay, SOD assay, GSH-Px assay and western blotting, respectively. It was demonstrated that PM2.5 exposure inhibited cell viability of all three cell lines (HaCaT, PIG1 and PIG3V cells). PM2.5 exposure attenuated the secretions of SCF and bFGF in HaCaT cells. Moreover, PM2.5 exposure attenuated the activation of tyrosinase and melanogenesis, inhibited cell migration, and induced apoptosis and oxidative stress injury in PIG1 cells and PIG3V cells. In addition, PM2.5 exposure caused upregulated cytosolic cytochrome C and activated caspase-3 in PIG1 cells and PIG3V cells. Furthermore, PM2.5 exposure activated the nuclear factor erythroid 2-related factor 2 and heme oxygenase-1 signaling pathway. The present results suggested that PM2.5 exposure could inhibit the secretions of SCF and bFGF in keratinocytes, and cause oxidative stress injury and melanin metabolic disorder in melanocytes. Therefore, PM2.5 could be a new risk factor for vitiligo.

A novel inhibitory role of microRNA-224 in particulate matter 2.5-induced asthmatic mice by inhibiting TLR2

Epidemiological studies have shown that elevated concentrations of particulate matter 2.5 (PM2.5) correlate with increased incidence of asthma. Studies have highlighted the implication of microRNAs (miRNAs) in asthmatic response. Here, the objective of this study is to explore the effect of miR-224 on PM2.5-induced asthmatic mice. Ovalbumin (OVA) was utilized to establish asthmatic mouse models, which were then exposed to PM2.5, followed by miR-224 expression detection. Next, lesions and collagen deposition area in lung tissue, ratio Treg/Th17, the expression of TLR4 and MYD88, inflammation, eosinophils (EOS) and airway remodelling were evaluated in OVA mice after injection with miR-224 agomir. Following isolation of mouse primary bronchial epithelial cells, miR-224 mimic and TLR2/TLR4 inhibitor were introduced to assess inflammation and the expression of TGF-β, MMP9, TIMP-1, Foxp3, RORγt, TLR2, TLR4 and MYD88. After exposure to PM2.5, lesions and collagen deposition were promoted in lung tissues, inflammation and EOS were increased in bronchoalveolar lavage fluid (BALF), and airway remodelling was enhanced in OVA mice. miR-224 was down-regulated, whereas TLR2/TLR4/MYD88 was up-regulated in OVA mice after treatment with PM2.5, accompanied by Treg/Th17 immune imbalance. Of note, bioinformatic prediction and dual luciferase reporter gene assay confirmed that TLR2 was a target gene of miR-224. Overexpressed miR-224 reduced expression of TGF-β, MMP9, TIMP-1 and RORγt and inflammation but increased Foxp3 expression in bronchial epithelial cells through down-regulating TLR2. In summary, overexpressed miR-224 suppressed airway epithelial cell inflammation and airway remodelling in PM2.5-induced asthmatic mice through decreasing TLR2 expression.

Short-term exposure to particulate matters is associated with septic emboli in infective endocarditis

This survey was to investigate the short-term effect of particulate matters (PMs) exposure on clinical and microbiological variables, especially septic emboli, in infective endocarditis (IE). The study analyzed 138 IE patients in Far Eastern Memorial Hospital from 2005 to 2015 and clinical variables were retrospectively requested. The data of air quality were recorded and collected by a network of 26 monitoring stations spreading in Northern part of Taiwan. We found that IE patients with septic emboli were found to be exposed to a significantly higher level of PM2.5 (32.01 ± 15.89 vs. 21.70 ± 13.05 μg/m, P < .001) and PM10 (54.57 ± 24.43 vs 40.98 ± 24.81 μg/m, P = .002) on lag 0 day when compared to those without. Furthermore, multivariate regression analysis revealed that that ambient exposure to PM2.5 (odds ratio: 3.87, 95% confidence interval: 1.31-8.31; P = .001) and PM10 (odds ratio: 4.58, 95% confidence interval: 2.03-10.32; P < .001) significantly increased risk of septic emboli in IE patients. To our knowledge, this is the first study demonstrating that short-term exposure to PMs was associated with septic emboli in IE.

Apigenin attenuates PM2.5-induced airway hyperresponsiveness and inflammation by down-regulating NF-κB in murine model of asthma

The purpose of this study was to investigate the anti-inflammatory potential of the natural flavonoid apigenin to mitigate the airway inflammation in asthmatic mice exposed to particulate matter (PM) 2.5, and examine the possible mechanisms involved. BALB/c mice were sensitized and challenged with ovalbumin (OVA), then administered apigenin at a dose of 20 mg/kg/day, followed by PM2.5 exposure at a dose of 100 μg/mouse before prior to each challenge. The results showed that PM2.5 exposure aggravated airway hyper-responsiveness (AHR) and led to a mixed T helper (Th)2 cell/interleukin (IL)-17 response in asthmatic mice. Apigenin treatment markedly decreased both AHR and the percentage of eosinophils, as well as neutrophil infiltration in the bronchoalveolar lavage fluid (BALF) and lung tissue of OVA-sensitized and PM2.5-exposed mice. There were significant reductions in the levels of total serum immunoglobulin IgE and T-helper cell type 2 (Th2)-related cytokines (IL-4, IL-13) and Th17-related cytokine IL-17 in BALF. In addition, treatment with apigenin down-regulated the expression of nuclear factor kappa-light -chain-enhancer of activated B cells (NF-κB) p65 submit in lung tissue of asthmatic mice. These data suggest that apigenin exhibited both anti-allergic and anti-neutrophil-related inflammatory activity in a murine asthma model exposed to PM2.5, possibly through modulating IL-17 and down-regulating the expression of NF-κB. Thus, apigenin may be a promising candidate for preventing PM2.5 exposure-enhanced pre-existing asthma.

Particulate Matter 2.5 Mediates Cutaneous Cellular Injury by Inducing Mitochondria-Associated Endoplasmic Reticulum Stress: Protective Effects of Ginsenoside Rb1

The prevalence of fine particulate matter-induced harm to the human body is increasing daily. The aim of this study was to elucidate the mechanism by which particulate matter 2.5 (PM_2.5) induces damage in human HaCaT keratinocytes and normal human dermal fibroblasts, and to evaluate the preventive capacity of the ginsenoside Rb1. PM_2.5 induced oxidative stress by increasing the production of reactive oxygen species, leading to DNA damage, lipid peroxidation, and protein carbonylation; this effect was inhibited by ginsenoside Rb1. Through gene silencing of endoplasmic reticulum (ER) stress-related genes such as PERK, IRE1, ATF, and CHOP, and through the use of the ER stress inhibitor tauroursodeoxycholic acid (TUDCA), it was demonstrated that PM_2.5-induced ER stress also causes apoptosis and ultimately leads to cell death; however, this phenomenon was reversed by ginsenoside Rb1. We also found that TUDCA partially restored the production of ATP that was inhibited by PM_2.5, and its recovery ability was significantly higher than that of ginsenoside Rb1, indicating that the process of ER stress leading to cell damage may also occur via the mitochondrial pathway. We concluded that ER stress acts alone or via the mitochondrial pathway in the induction of cell damage by PM_2.5, and that ginsenoside Rb1 blocks this process. Ginsenoside Rb1 shows potential for use in skin care products to protect the skin against damage by fine particles.

Impact and Interactions of Policies for Mitigation of Air Pollutants and Greenhouse Gas Emissions in Korea

Korea faces a challenging task of simultaneously reducing emissions of air pollutants and greenhouse gases (GHG). Since both are emitted from the same sources such as fossil fuel combustion and economic activities, there could be commonalities and interactions between the policies for reducing each of them. A static computable general equilibrium model is developed to observe the economic impact of policies for reducing air pollutants or GHG and the interactions between those policies in Korea. The results show that reducing one of the air pollutants, particulate matter 2.5 (PM_2.5) emissions by 30% from the business-as-usual (BAU) in 2022 will lead to reduction of GHG emissions by 22.8% below the BAU level, exceeding the national GHG reduction target. Also, by achieving the domestic GHG reduction target, which is 32.5% below the BAU level by 2030, PM_2.5 emissions will be reduced by 32.8%. The costs of reducing air pollutants and greenhouse gas are high, reaching from 0.34% to 1.75% of gross domestic product, and the reduction causes an asymmetrical damage to emission intensive industries. The sum of the benefits from air pollutants and GHG reduction is estimated to be 0.4 to 1.2 times greater than the costs, depending on the scenario.

Effect of particulate matter 2.5 on gene expression profile and cell signaling in JEG-3 human placenta cells

Particulate matter the environmental toxicant, with a diameter less than or equal to 2.5 μm (PM_2.5 ) is a common cause of several respiratory diseases. In recent years, several studies have suggested that PM_2.5 can influence diverse diseases, such as respiratory diseases, cardiovascular diseases, metabolic diseases, dementia, and female reproductive disorders, and unhealthy birth outcomes. In addition, several epidemiological studies have reported that adverse health effects of PM_2.5 can differ depending on regional variations. In the present study, to evaluate specific adverse health effects of PM_2.5 , we collected two different PM_2.5 samples from an underground parking lot and ambient air, and we evaluated cytotoxicity with eight different cell lines originating from human organs. Then, we selected JEG-3 human placenta cells, which show high cytotoxicity to both PM samples. Through RNA sequencing, gene expression profiling, and a gene ontology (GO) analysis of JEG-3 after exposure to two different PM_2.5 samples, we identified 1021 commonly expressed genes involved in immune responses, the regulation of apoptosis, and so forth, which are known to induce several adverse health effects. In addition, we identified genes related to the calcium-signaling pathway, steroid hormone biosynthesis, and the cytokine-cytokine receptor interaction through a Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Then, we confirmed these gene expressions using qRT-PCR, and the protein levels of mitogen-activated protein kinases and COX-2 with progesterone decreased using western blotting and enzyme-linked immunosorbent assay. In conclusion, this study suggests the possible toxic mechanism of human placenta that might be associated with PM_2.5 -induced female reproductive disorders.

Editor's Highlight: Modifying Role of Endothelial Function Gene Variants on the Association of Long-Term PM2.5 Exposure With Blood DNA Methylation Age: The VA Normative Aging Study

Recent studies have reported robust associations of long-term PM2.5 exposure with DNA methylation-based measures of aging; yet, the molecular implications of these relationships remain poorly understood. We evaluated if genetic variation in 3 biological pathways implicated in PM2.5-related disease-oxidative stress, endothelial function, and metal processing-could modify the effect of PM2.5 on DNAm-age, one prominent DNA methylation-based measure of biological age. This analysis was based on 552 individuals from the Normative Aging Study with at least one visit between 2000 and 2011 (n = 940 visits). A genetic-score approach was used to calculate aging-risk variant scores for endothelial function, oxidative stress, and metal processing pathways. One-year PM2.5 and PM2.5 component (sulfate and ammonium) levels at participants' addresses were estimated using the GEOS-chem transport model. Blood DNAm-age was calculated using CpG sites on the Illumina HumanMethylation450 BeadChip. In fully-adjusted linear mixed-effects models, the effects of sulfate on DNAm-age (in years) were greater in individuals with high aging-risk endothelial function variant scores when compared with individuals with low aging-risk endothelial function variant scores (Pinteraction = 0.0007; βHigh = 1.09, 95% CIHigh: 0.70, 1.48; βLow = 0.40, 95% CILow: 0.14, 0.67). Similar trends were observed in fully adjusted models of ammonium and total PM2.5 alone. No effect modification was observed by oxidative stress and metal processing variant scores. Secondary analyses revealed significant associations of serum endothelial markers, intercellular adhesion molecule-1 (β = 0.01, 95% CI: 0.002, 0.012) and vascular cell adhesion molecule-1 (β = 0.002, 95% CI: 0.0005, 0.0026), with DNAm-age. Our results add novel evidence that endothelial physiology may be important to DNAm-age relationships, but further research is required to establish their generalizability.

Function of PM2.5 in the pathogenesis of lung cancer and chronic airway inflammatory diseases

Previous research has identified that air pollution is associated with various respiratory diseases, but few studies have investigated the function served by particulate matter 2.5 (PM2.5) in these diseases. PM2.5 is known to cause epigenetic and microenvironmental alterations in lung cancer, including tumor-associated signaling pathway activation mediated by microRNA dysregulation, DNA methylation, and increased levels of cytokines and inflammatory cells. Autophagy and apoptosis of tumor cells may also be detected in lung cancer associated with PM2.5 exposure. A number of mechanisms are involved in triggering and aggravating asthma and COPD, including PM2.5-induced cytokine release and oxidative stress. The present review is an overview of the underlying molecular mechanisms of PM2.5-induced pathogenesis in lung cancer and chronic airway inflammatory diseases.

Instillation of particulate matter 2.5 induced acute lung injury and attenuated the injury recovery in ACE2 knockout mice

Inhaled particulate matter 2.5 (PM_2.5) can cause lung injury by inducing serious inflammation in lung tissue. Renin-angiotensin system (RAS) is involved in the pathogenesis of inflammatory lung diseases and regulates inflammatory response. Angiotensin-converting enzyme II (ACE2), which is produced through the angiotensin-converting enzyme (ACE)/angiotensin II (Ang II) axis, protects against lung disease. However, few studies have focused on the relationships between PM_2.5 and ACE2. Therefore, we aimed to explore the role of ACE2 in PM_2.5-induced acute lung injury (ALI). An animal model of PM_2.5-induced ALI was established with wild type (C57BL/6, WT) and ACE2 gene knockout (ACE2 KO) mice. The mice were exposed to PM_2.5 through intratracheal instillation once a day for 3 days (6.25 mg/kg/day) and then sacrificed at 2 days and 5 days after PM_2.5 instillation. The results show that resting respiratory rate (RRR), levels of inflammatory cytokines, ACE and MMPs in the lungs of WT and ACE2 KO mice were significantly increased at 2 days postinstillation. At 5 days postinstillation, the PM_2.5-induced ALI significantly recovered in the WT mice, but only partially recovered in the ACE2 KO mice. The results hint that PM_2.5 could induce severe ALI through pulmonary inflammation, and the repair after acute PM_2.5 postinstillation could be attenuated in the absence of ACE2. Additionally, our results show that PM_2.5-induced ALI is associated with signaling p-ERK1/2 and p-STAT3 pathways and ACE2 knockdown could increase pulmonary p-STAT3 and p-ERK1/2 levels in the PM_2.5-induced ALI.

Therapeutic effects of stemonine on particulate matter 2.5-induced chronic obstructive pulmonary disease in mice

Particulate matter 2.5 (PM_2.5) is a growing concern worldwide due to its association with respiratory diseases, including chronic obstructive pulmonary disease (COPD). Stemonine, a traditional Chinese herb, has been demonstrated to exhibit anti-inflammatory and antioxidant properties, making it a potential drug for the treatment of respiratory diseases. The therapeutic effects of stemonine on mice with PM_2.5-induced COPD were investigated in the present study. Kunming mice were randomly divided into the following five groups (n=10/group): Control, model, low-dose stemonine, moderate-dose stemonine and high-dose stemonine. The model mice received an intranasal instillation of PM_2.5 suspension (40 mg/kg). The levels of specific enzymes, markers of oxidative stress, and the inflammatory cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-6 were measured in the bronchoalveolar lavage fluid of the mice using ELISA kits. Hematoxylin and eosin staining was performed to determine inflammatory changes to the lung tissue. It was demonstrated that stemonine could significantly alleviate lung injury by decreasing the levels of enzymes and cytokines associated with inflammation and oxidative stress in a dose-dependent manner. In addition, stemonine dose-dependently increased the amount of superoxide dismutase. These results suggest that stemonine reduces lung inflammation in mice with PM_2.5-induced COPD, providing a novel approach for the treatment of PM_2.5-induced respiratory diseases.

Impacts of the Mitochondrial Genome on the Relationship of Long-Term Ambient Fine Particle Exposure with Blood DNA Methylation Age

The mitochondrial genome has long been implicated in age-related disease, but no studies have examined its role in the relationship of long-term fine particle (PM2.5) exposure and DNA methylation age (DNAm-age)-a novel measure of biological age. In this analysis based on 940 observations between 2000 and 2011 from 552 Normative Aging Study participants, we determined the roles of mitochondrial DNA haplogroup variation and mitochondrial genome abundance in the relationship of PM2.5 with DNAm-age. We used the GEOS-chem transport model to estimate address-specific, one-year PM2.5 levels for each participant. DNAm-age and mitochondrial DNA markers were measured from participant blood samples. Nine haplogroups (H, I, J, K, T, U, V, W, and X) were present in the population. In fully adjusted linear mixed-effects models, the association of PM2.5 with DNAm-age (in years) was significantly diminished in carriers of haplogroup V (Pinteraction = 0.01; β = 0.18, 95%CI: -0.41, 0.78) compared to noncarriers (β = 1.25, 95%CI: 0.58, 1.93). Mediation analysis estimated that decreases in mitochondrial DNA copy number, a measure of mitochondrial genome abundance, mediated 12% of the association of PM2.5 with DNAm-age. Our data suggests that the mitochondrial genome plays a role in DNAm-age relationships particularly in the context of long-term PM2.5 exposure.

Pro-inflammatory response and oxidative stress induced by specific components in ambient particulate matter in human bronchial epithelial cells

Previous studies have shown that biological effect of particulate matter (PM2.5) is involved in including chemical composition and mass concentration, but the precise components and biological action on human bronchial epithelial cell line (BEAS-2B) are still unclear. The aim of this study was to evaluate the in vitro toxicity of PM2.5 collected at six urban sites in China, and to investigate how particle composition affects cytotoxicity. We used human bronchial epithelial (BEAS-2B) cell lines as model in vitro to expose to PM2.5 from different source, and then reactive oxygen species (ROS), superoxide dismutase activity and total antioxidant capacity were analyzed. Furthermore, we estimated the polycyclic aromatic hydrocarbon (PAH) and transition metal and the endotoxin contents. The mRNA expression of IL-1β and IL-10 following exposure to PM2.5 was measured by QRT-PCR. We also observed the mitochondrial membrane potential (MMP) using JC-1 staining, and apoptosis of BEAS-2B using flow cytometry. In addition, double-stranded DNA breaks (DSBs) were assessed using γ-H2AX immunofluorescence. Our results show that high concentrations of PAHs and elemental Ni were strongly associated with high apoptosis rates and high expression of IL-1β, in addition, Fe element was associated with the ROS level, furthermore, Fe and Cr element were associated with DNA damage in BEAS-2B cells. The cytotoxic effects of urban PM2.5 derived from six different cities in China appear dependent on the specific components in each. Our results indicate that air quality standards based on PM2.5 components may be more relevant than concentration-response functions (CRF). © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 923-936, 2016.

Long-term ambient particle exposures and blood DNA methylation age: findings from the VA normative aging study

BACKGROUND

Ambient particles have been shown to exacerbate measures of biological aging; yet, no studies have examined their relationships with DNA methylation age (DNAm-age), an epigenome-wide DNA methylation based predictor of chronological age.

OBJECTIVE

We examined the relationship of DNAm-age with fine particulate matter (PM2.5), a measure of total inhalable particle mass, and black carbon (BC), a measure of particles from vehicular traffic.

METHODS

We used validated spatiotemporal models to generate 1-year PM2.5 and BC exposure levels at the addresses of 589 older men participating in the VA Normative Aging Study with 1-3 visits between 2000 and 2011 (n = 1032 observations). Blood DNAm-age was calculated using 353 CpG sites from the Illumina HumanMethylation450 BeadChip. We estimated associations of PM2.5 and BC with DNAm-age using linear mixed effects models adjusted for age, lifestyle/environmental factors, and aging-related diseases.

RESULTS

After adjusting for covariates, a 1-µg/m3 increase in PM2.5 (95% CI: 0.30, 0.75, P<0.0001) was significantly associated with a 0.52-year increase in DNAm-age. Adjusted BC models showed similar patterns of association (β = 3.02, 95% CI: 0.48, 5.57, P = 0.02). Only PM2.5 (β = 0.54, 95% CI: 0.24, 0.84, P = 0.0004) remained significantly associated with DNAm-age in two-particle models. Methylation levels from 20 of the 353 CpGs contributing to DNAm-age were significantly associated with PM2.5 levels in our two-particle models. Several of these CpGs mapped to genes implicated in lung pathologies including LZTFL1, PDLIM5, and ATPAF1.

CONCLUSION

Our results support an association of long-termambient particle levels with DNAm-age and suggest that DNAm-age is a biomarker of particle-related physiological processes.

Effects of the Particulate Matter₂.₅ (PM₂.₅) on Lipoprotein Metabolism, Uptake and Degradation, and Embryo Toxicity

Particulate matter2.5 (PM2.5) is notorious for its strong toxic effects on the cardiovascular, skin, nervous, and reproduction systems. However, the molecular mechanism by which PM2.5 aggravates disease progression is poorly understood, especially in a water-soluble state. In the current study, we investigated the putative physiological effects of aqueous PM2.5 solution on lipoprotein metabolism. Collected PM2.5 from Seoul, Korea was dissolved in water, and the water extract (final 3 and 30 ppm) was treated to human serum lipoproteins, macrophages, and dermal cells. PM2.5 extract resulted in degradation and aggregation of high-density lipoprotein (HDL) as well as low-density lipoprotein (LDL); apoA-I in HDL aggregated and apo-B in LDL disappeared. PM2.5 treatment (final 30 ppm) also induced cellular uptake of oxidized LDL (oxLDL) into macrophages, especially in the presence of fructose (final 50 mM). Uptake of oxLDL along with production of reactive oxygen species was accelerated by PM2.5 solution in a dose-dependent manner. Further, PM2.5 solution caused cellular senescence in human dermal fibroblast cells. Microinjection of PM2.5 solution into zebrafish embryos induced severe mortality accompanied by impairment of skeletal development. In conclusion, water extract of PM2.5 induced oxidative stress as a precursor to cardiovascular toxicity, skin cell senescence, and embryonic toxicity via aggregation and proteolytic degradation of serum lipoproteins.

Interleukin 13- and interleukin 17A-induced pulmonary hypertension phenotype due to inhalation of antigen and fine particles from air pollution

Pulmonary hypertension has a marked detrimental effect on quality of life and life expectancy. In a mouse model of antigen-induced pulmonary arterial remodeling, we have recently shown that coexposure to urban ambient particulate matter (PM) significantly increased the thickening of the pulmonary arteries and also resulted in significantly increased right ventricular systolic pressures. Here we interrogate the mechanism and show that combined neutralization of interleukin 13 (IL-13) and IL-17A significantly ameliorated the increase in right ventricular systolic pressure, the circumferential muscularization of pulmonary arteries, and the molecular change in the right ventricle. Surprisingly, our data revealed a protective role of IL-17A for the antigen- and PM-induced severe thickening of pulmonary arteries. This protection was due to the inhibition of the effects of IL-13, which drove this response, and the expression of metalloelastase and resistin-like molecule α. However, the latter was redundant for the arterial thickening response. Anti-IL-13 exacerbated airway neutrophilia, which was due to a resulting excess effect of IL-17A, confirming concurrent cross inhibition of IL-13- and IL-17A-dependent responses in the lungs of animals exposed to antigen and PM. Our experiments also identified IL-13/IL-17A-independent molecular reprogramming in the lungs induced by exposure to antigen and PM, which indicates a risk for arterial remodeling and protection from arterial constriction. Our study points to IL-13- and IL-17A-coinduced inflammation as a new template for biomarkers and therapeutic targeting for the management of immune response-induced pulmonary hypertension.