Effects of Particulate Matter 10 Inhalation on Lung Tissue RNA expression in a Murine Model

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.

Cordyceps militaris Grown on Germinated Rhynchosia nulubilis (GRC) Encapsulated in Chitosan Nanoparticle (GCN) Suppresses Particulate Matter (PM)-Induced Lung Inflammation in Mice

Cordyceps militaris grown on germinated Rhynchosia nulubilis (GRC) exerts various biological effects, including anti-allergic, anti-inflammatory, and immune-regulatory effects. In this study, we investigated the anti-inflammatory effects of GRC encapsulated in chitosan nanoparticles (CN) against particulate matter (PM)-induced lung inflammation. Optimal CN (CN6) (CHI: TPP w/w ratio of 4:1; TPP pH 2) exhibited a zeta potential of +22.77 mV, suitable for GRC encapsulation. At different GRC concentrations, higher levels (60 and 120 mg/mL) led to increased negative zeta potential, enhancing stability. The optimal GRC concentration for maximum entrapment (31.4 ± 1.35%) and loading efficiency (7.6 ± 0.33%) of GRC encapsulated in CN (GCN) was 8 mg/mL with a diameter of 146.1 ± 54 nm and zeta potential of +30.68. In vivo studies revealed that administering 300 mg/kg of GCN significantly decreased the infiltration of macrophages and T cells in the lung tissues of PM-treated mice, as shown by immunohistochemical analysis of CD4 and F4/80 markers. Additionally, GCN ameliorated PM-induced lung tissue damage, inflammatory cell infiltration, and alveolar septal hypertrophy. GCN also decreased total cells and neutrophils, showing notable anti-inflammatory effects in the bronchoalveolar lavage fluid (BALF) from PM-exposed mice, compared to GRC. Next the anti-inflammatory properties of GCN were further explored in PM- and LPS-exposed RAW264.7 cells; it significantly reduced PM- and LPS-induced cell death, NO production, and levels of inflammatory cytokine mRNAs (IL-1β, IL-6, and COX-2). GCN also suppressed NF-κB/MAPK signaling pathways by reducing levels of p-NF-κB, p-ERK, and p-c-Jun proteins, indicating its potential in managing PM-related inflammatory lung disease. Furthermore, GCN significantly reduced PM- and LPS-induced ROS production. The enhanced bioavailability of GRC components was demonstrated by an increase in fluorescence intensity in the intestinal absorption study using FITC-GCN. Our data indicated that GCN exhibited enhanced bioavailability and potent anti-inflammatory and antioxidant effects in cells and in vivo, making it a promising candidate for mitigating PM-induced lung inflammation and oxidative stress.

Particulate matter exposure induces adverse effects on endometrium and fertility via aberrant inflammatory and apoptotic pathways in vitro and in vivo

This study aimed to evaluate the adverse effects of particulate matter (PM) exposure on endometrial cells and fertility and to identify possible underlying mechanisms. Thirteen women (aged 15-52 years) were included in this study. Enrolled patients underwent laparoscopic surgery at Gangnam Severance Hospital between 1 January and 31 December 2021. For in vivo experiments, 36 female and nine male C57BL/6 mice were randomly divided into control(vehicle), low-dose(10 mg/kg/d), and high-dose exposure groups(20 mg/kg/d). PM was inhaled nasally for four weeks and natural mating was performed. NIST® SRM® 1648a was used for PM exposure. qRT-PCR, western blotting and Masson's trichrome staining were performed. PM treatment in human endometrial stromal cells induced inflammation with significant upregulation of IL-1β, p-NF-kB, and p-c-Jun compared to those of controls. Additionally, PM treatment significantly increased apoptosis in human endometrial stromal cells by downregulating p-AKT and upregulating p-p53/p53, Cas-3, BAX/Bcl-2, p-AMPK, and p-ERK. After PM treatment, the relative expression of IL-1β, IL-6, TNF-α, p-NF-κB, p-c-Jun, and p-Nrf2/Nrf2 significantly increased in murine endometrium compared to those of the controls. Expression of apoptotic proteins p53, p27, and Cas-3, was also significantly elevated in murine endometrium of the PM exposure group compared to that of the controls. A significant increase in expression of procollagen Ⅰ, and Masson's trichrome staining scores in the murine endometrium was noted after PM treatment. PM treatment significantly decreased ERα expression. After natural mating, all 3 female mice in the control group gave birth to 25 offspring (mean 8.1), whereas in the low-dose PM treatment group, two of three female mice gave birth to nine offspring (mean 4.5). No pregnant mice or offspring was present in the high-dose PM treatment group. PM exposure induces adverse effects on the endometrium through aberrant activation of inflammatory and apoptotic pathways and is associated with detrimental effects on murine fertility.

TGF-β Regulates m6A RNA Methylation after PM2.5 Exposure

PM2.5 exposure leads to a variety of respiratory diseases, including pulmonary fibrosis, metastatic lung cancer, etc. Exposure to PM2.5 results in the alteration of epigenetic modification. M6A RNA methylation is an essential epigenetic modification that regulates gene expression at the post-transcriptional level. Our previous study found that PM2.5 exposure up-regulated m6A RNA methylation and TGF-β expression level in the lung, but the mechanisms and pathways of PM2.5 regulation of m6A RNA methylation are still unclear. Moreover, a previous study reported that the TGF-β signal pathway could regulate m6A RNA methylation. Based on this evidence, we investigate the role of the TGF-β signaling pathway in PM2.5-induced m6A RNA methylation with the A549 cell line. Our results showed that PM2.5 could induce upregulation of m6A RNA methylation, accompanied by increased expression of TGF-β, Smad3, methyltransferase-like 3 (METTL3), methyltransferase-like 14 (METTL14). Furthermore, these alterations induced by PM2.5 exposure could be reversed by treatment with TGF-β inhibitor. Therefore, we speculated that the TGF-β signal pathway plays an indispensable role in regulating m6A RNA methylation after PM2.5 exposure. Our study demonstrates that PM2.5 exposure influences m6A RNA methylation by inducing the alteration of the TGF-β signal pathway, which could be an essential mechanism for lung-related diseases induced by PM2.5 exposure.

Particulate matter10-induced airway inflammation and fibrosis can be regulated by chitinase-1 suppression

BACKGROUND

Particulate matter₁₀ (PM₁₀) can induce airway inflammation and fibrosis. Recently, chitinase-1 has been shown to play key roles in inflammation and fibrosis. We aimed to investigate the effects of chitinase-1 inhibitor in PM₁₀-treated murine mice models.

METHODS

In female BALB/c mice, PM₁₀ was intranasally administered six times over 3 weeks, and ovalbumin (OVA) was intraperitoneally injected and then intranasally administered. Chitinase-1 inhibitor (CPX) 6 times over 3 weeks or dexamethasone 3 times in the last week were intraperitoneally administered. Two days after the last challenges, mice were euthanized. Messenger RNA sequencing using lung homogenates was conducted to evaluate signaling pathways.

RESULTS

PM₁₀ and/or OVA-induced airway inflammation and fibrosis murine models were established. CPX and dexamethasone ameliorated PM₁₀ or PM₁₀/OVA-induced airway hyper-responsiveness, airway inflammation, and fibrosis. CPX and dexamethasone also reduced levels of various inflammatory markers in lung homogenates. PM₁₀ and OVA also induced changes in mRNA expression across an extreme range of genes. CPX and dexamethasone decreased levels of mRNA expression especially associated with inflammation and immune regulation. They also significantly regulated asthma and asthma-related pathways, including the JACK-STAT signaling pathway.

CONCLUSIONS

Chitinase-1 suppression by CPX can regulate PM₁₀- and OVA-induced and aggravated airway inflammation and fibrosis via an asthma-related signaling pathway.

Airborne Exposure of the Cornea to PM10 Induces Oxidative Stress and Disrupts Nrf2 Mediated Anti-Oxidant Defenses

The purpose of this study is to test the effects of whole-body animal exposure to airborne particulate matter (PM) with an aerodynamic diameter of <10 μm (PM10) in the mouse cornea and in vitro. C57BL/6 mice were exposed to control or 500 µg/m3 PM10 for 2 weeks. In vivo, reduced glutathione (GSH) and malondialdehyde (MDA) were analyzed. RT-PCR and ELISA evaluated levels of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling and inflammatory markers. SKQ1, a novel mitochondrial antioxidant, was applied topically and GSH, MDA and Nrf2 levels were tested. In vitro, cells were treated with PM10 ± SKQ1 and cell viability, MDA, mitochondrial ROS, ATP and Nrf2 protein were tested. In vivo, PM10 vs. control exposure significantly reduced GSH, corneal thickness and increased MDA levels. PM10-exposed corneas showed significantly higher mRNA levels for downstream targets, pro-inflammatory molecules and reduced Nrf2 protein. In PM10-exposed corneas, SKQ1 restored GSH and Nrf2 levels and lowered MDA. In vitro, PM10 reduced cell viability, Nrf2 protein, and ATP, and increased MDA, and mitochondrial ROS; while SKQ1 reversed these effects. Whole-body PM10 exposure triggers oxidative stress, disrupting the Nrf2 pathway. SKQ1 reverses these deleterious effects in vivo and in vitro, suggesting applicability to humans.

Curcumin Ameliorates Particulate Matter-Induced Pulmonary Injury through Bimodal Regulation of Macrophage Inflammation via NF-κB and Nrf2

The direct effects of particulate matter (PM) on lung injury and its specific molecular mechanisms are unclear. However, experimental evidence has shown that oxidative stress-mediated inflammation in macrophages is the main pathological outcome of PM exposure. Curcumin has been reported to protect organs against the disturbance of homeostasis caused by various toxic agents through anti-inflammatory and antioxidative effects. However, the protective action of curcumin against PM-induced pulmonary inflammation and the underlying mechanism have not been thoroughly investigated. In this study, we established a PM-induced pulmonary inflammation mouse model using the intratracheal instillation method to investigate the protective ability of curcumin against PM-induced pulmonary inflammation. Compared to the mice treated with PM only, the curcumin-treated mice showed alleviated alveolar damage, decreased immune cell infiltration, and reduced proinflammatory cytokine production in both lung tissue and BALF. To evaluate the underlying mechanism, the mouse macrophage cell line RAW264.7 was used. Pretreatment with curcumin prevented the production of PM-induced proinflammatory cytokines by deactivating NF-κB through the suppression of MAPK signaling pathways. Furthermore, curcumin appears to attenuate PM-induced oxidative stress through the activation of Nrf2 and downstream antioxidant signaling. Our findings demonstrate that curcumin protects against PM-induced lung injury by suppressing oxidative stress and inflammatory activation in macrophages.

Role of the mucin-like glycoprotein FCGBP in mucosal immunity and cancer

IgGFc-binding protein (FCGBP) is a mucin first detected in the intestinal epithelium. It plays an important role in innate mucosal epithelial defense, tumor metastasis, and tumor immunity. FCGBP forms disulfide-linked heterodimers with mucin-2 and members of the trefoil factor family. These formed complexes inhibit bacterial attachment to mucosal surfaces, affect the motility of pathogens, and support their clearance. Altered FCGBP expression levels may be important in the pathologic processes of Crohn’s disease and ulcerative colitis. FCGBP is also involved in regulating the infiltration of immune cells into tumor microenvironments. Thus, the molecule is a valuable marker of tumor prognosis. This review summarizes the functional relevance and role of FCGBP in immune responses and disease development, and highlights the potential role in diagnosis and predicting tumor prognosis.

SNORD15B and SNORA5C: Novel Diagnostic and Prognostic Biomarkers for Colorectal Cancer

Colorectal cancer (CRC) is presenting a global public health problem with high incidence and mortality. Early diagnosis and treatment are the most important strategies to improve prognosis of this disease. Besides fecal occult blood test (FOBT) and colonoscopy, the most widely used methods for CRC screening currently, more effective methods for early diagnosis or prognostic prediction for CRC are needed. Small nucleolar RNAs (snoRNAs) is a class of noncoding RNAs (ncRNAs) playing crucial roles in carcinogenesis and considered to be promising tumor biomarker. In this study, we found that SNORD15B, SNORD48, and SNORA5C were significantly upregulated in CRC tissues. High levels of SNORD15B, SNORD48, or SNORA5C predicted poor clinical outcomes of CRC patients. Forced expression of SNORD15B or SNORA5C in CRC cells promoted proliferation and colony formation. In a further investigation, association between the level of SNORD15B/SNORA5C and clinicopathological parameters of CRC patient cohorts was analyzed based on data from The Cancer Genome Atlas (TCGA). We found that high expressions of SNORD15B and SNORA5C were significantly associated with age, lymphatic invasion, and history of colon polyps, and they were proved to be independent risk factors for survival of CRC patients. This study confirms that SNORD15B and SNORA5C have oncogenic effects in carcinogenesis of CRC. The findings suggest the two genes as potential diagnostic and prognostic biomarkers for CRC.

Reliability of Portable Spirometry Performed in the Korea National Health and Nutrition Examination Survey Compared to Conventional Spirometry

Background

The Korea National Health and Nutrition Examination Survey (KNHANES) is a well-designed survey to collect national data, which many researchers have used for their studies. In KNHANES, although portable spirometry was used, its reliability has not been verified.

Methods

We prospectively enrolled 58 participants from four Korean institutions. The participants were classified into normal pattern, obstructive pattern, and restrictive pattern groups according to their previous spirometry results. Lung function was estimated by conventional spirometry and portable spirometry, and the results were compared.

Results

The intraclass correlation coefficients of forced vital capacity (FVC) (coefficient, 9.993; 95% confidence interval [CI], 0.988–0.996), forced expiratory volume in 1 second (FEV₁) (coefficient, 0.997; 95% CI, 0.995–0.998), FEV₁/FVC ratio (coefficient, 0.995; 95% CI, 0.992–0.997), and forced expiratory flow at 25–75% (FEF25–75%; coefficient, 0.991; 95% CI, 0.984–0.994) were excellent (all p<0.001). In the subgroup analysis, the results of the three parameters were similar in all groups. In the overall and subgroup analyses, Pearson’s correlation of all the parameters was also excellent in the total (coefficient, 0.986–0.994; p<0.001) and subgroup analyses (coefficient, 0.915–0.995; p<0.001). In the paired t-test, FVC, FEV₁/FVC, and FEF25–75% estimated by the two instruments were statistically different. However, FEV₁ was not significantly different.

Conclusion

Lung function estimated by portable spirometry was well-correlated with that estimated by conventional spirometry. Although the values had minimal differences between them, we suggest that the spirometry results from the KNHANES are reliable.