Coal dust exposure triggers heterogeneity of transcriptional profiles in mouse pneumoconiosis and Vitamin D remedies

Lsm2 is critical to club cell proliferation and its inhibition aggravates COPD progression

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a prevalent respiratory condition, with its severity inversely related to the levels of Club cell 10 kDa secretory protein (CC10). The gene Lsm2, involved in RNA metabolism and cell proliferation, has an unclear role in COPD development.

METHODS

An in vitro COPD model was developed by stimulating 16HBE cells with cigarette smoke extract (CSE). To establish an in vivo COPD model, mice with defective Lsm2 gene expression in lung or club cells were exposed to cigarette smoke for 3 months. Multiplexed immunohistochemistry (mIHC) was employed to identify the specific cells where Lsm2 gene expression is predominant. RNA sequencing and single-nucleus RNA sequencing were conducted to investigate the role of Lsm2 in the pathogenesis of COPD.

RESULTS

In this study, we found that cigarette smoke extract increases Lsm2 expression, and knocking down Lsm2 in 16HBE cells significantly reduces cell viability in vitro. mIHC showed that Lsm2 is primarily expressed in Club cells. Knockout of Lsm2, either in the lungs or specifically in Club cells, exacerbated lung injury and inflammation caused by cigarette smoke exposure in vivo. Single-nucleus RNA sequencing analysis revealed that Club cell-specific knockout of Lsm2 leads to a reduction in the Club cell population, particularly those expressing Chia1+/Crb1+. This decrease in Club cells subsequently reduces the number of ciliated epithelial cells.

CONCLUSION

Knocking out Lsm2 in Club cells results in a significant decrease in Club cell numbers, which subsequently leads to a reduction in ciliated epithelial cells. This increased lung vulnerability to cigarette smoke and accelerating the progression of COPD. Our findings highlight that Lsm2 is critical to club cell proliferation and its inhibition aggravates COPD progression.

TFEB/LAMP2 contributes to PM0.2-induced autophagy-lysosome dysfunction and alpha-synuclein dysregulation in astrocytes

Atmospheric particulate matter (PM) exacerbates the risk factor for Alzheimer's and Parkinson's diseases (PD) by promoting the alpha-synuclein (α-syn) pathology in the brain. However, the molecular mechanisms of astrocytes involvement in α-syn pathology underlying the process remain unclear. This study investigated PM with particle size <200 nm (PM0.2) exposure-induced α-syn pathology in ICR mice and primary astrocytes, then assessed the effects of mammalian target of rapamycin inhibitor (PP242) in vitro studies. We observed the α-syn pathology in the brains of exposed mice. Meanwhile, PM0.2-exposed mice also exhibited the activation of glial cell and the inhibition of autophagy. In vitro study, PM0.2 (3, 10 and 30 µg/mL) induced inflammatory response and the disorders of α-syn degradation in primary astrocytes, and lysosomal-associated membrane protein 2 (LAMP2)-mediated autophagy underlies α-syn pathology. The abnormal function of autophagy-lysosome was specifically manifested as the expression of microtubule-associated protein light chain 3 (LC3II), cathepsin B (CTSB) and lysosomal abundance increased first and then decreased, which might both be a compensatory mechanism to toxic α-syn accumulation induced by PM0.2. Moreover, with the transcription factor EB (TFEB) subcellular localization and the increase in LC3II, LAMP2, CTSB, and cathepsin D proteins were identified, leading to the restoration of the degradation of α-syn after the intervention of PP242. Our results identified that PM0.2 exposure could promote the α-syn pathological dysregulation in astrocytes, providing mechanistic insights into how PM0.2 increases the risk of developing PD and highlighting TFEB/LAMP2 as a promising therapeutic target for antagonizing PM0.2 toxicity.

Associations of coal mine dust exposure with arterial stiffness and atherosclerotic cardiovascular disease risk in chinese coal miners

OBJECTIVE

Whether coal mine dust exposure increases cardiovascular diseases (CVDs) risk was rarely explored. Our objective was to examine the association between coal mine dust exposure and cardiovascular risk.

METHODS

We estimated cumulative coal mine dust exposure (CDE) for 1327 coal miners by combining data on workplace dust concentrations and work history. We used brachial-ankle pulse wave velocity (baPWV, a representative indicator of arterial stiffness) and ten-year atherosclerotic cardiovascular disease (ASCVD) risk to assess potential CVD risk, exploring their associations with CDE.

RESULTS

Positive dose-response relationships of CDE with baPWV and ten-year ASCVD risk were observed after adjusting for covariates. Specifically, each 1 standard deviation (SD) increase in CDE was related to a 0.27 m/s (95% CI: 0.21, 0.34) increase in baPWV and a 1.29 (95% CI: 1.14, 1.46) elevation in OR (odds ratio) of risk of abnormal baPWV. Moreover, each 1 SD increase in CDE was associated with a 0.74% (95% CI: 0.63%, 0.85%) increase in scores of ten-year ASCVD and a 1.91 (95% CI: 1.62, 2.26) increase in OR of risk of ten-year ASCVD. When compared with groups unexposed to coal mine dust, significant increase in the risk of arterial stiffness and ten-year ASCVD in the highest CDE groups were detected.

CONCLUSION

The study suggested that cumulative exposure to coal mine dust was associated with elevated arterial stiffness and ten-year ASCVD risk in a dose-response manner. These findings contribute valuable insights for cardiovascular risk associated with coal mine dust.

Coal mining environment causes adverse effects on workers

Background

The objective of this study is to study the adverse effects of coal mining environment on workers to discover early effective biomarkers.

Methods

The molecular epidemiological study was conducted with 502 in-service workers, who were divided into miner and auxiliary. We measured the individual levels of dust exposure for participants. Clinical examinations were conducted by qualified doctors. Peripheral blood was collected to measure biochemistry, hemogram, and karyocyte apoptosis.

Results

All workers were healthy who have not found with any diseases that can be diagnosed medically in the physical examination and showed no difference in dust exposure level, age, height, weight, and body mass index between groups. The working years of miners were lower than that of auxiliaries (p < 0.001). Compared with auxiliaries, the concentration and percentage of lymphocytes (p = 0.040, p = 0.012), basophils (p = 0.027, p = 0.034), and red blood cells (p < 0.001) and the concentration of hemoglobin of miners were lower (p < 0.001). The percentage of neutrophils (p = 0.003), the concentration of mean corpuscular hemoglobin concentration (p = 0.002), and the proportion of karyocyte apoptosis in miners were higher (p < 0.001). Miners presented higher blood urea nitrogen (p < 0.001), ratio of blood urea nitrogen to creatinine (p < 0.001), the high density lipoprotein cholesterol (p < 0.001), lower creatinine (p < 0.05), and cholesterol (p < 0.001).

Conclusion

The coal mining environment impacted mining workers' immune function, renal function, and the hematopoietic system, including BUN/CRE, HGB, RBC, and LYMPH, which could be used as early biomarkers to screen the health of coal miners.

Vitamin D3 reverses immune tolerance and enhances the cytotoxicity of effector T cells in coal pneumoconiosis

Coal worker's pneumoconiosis (CWP) is a common occupational disease that coal miners are highly susceptible due to long-term exposure to coal dust particles (CDP). CWP can induce the accumulation of immune cells surrounding the bronchioles and alveoli in the lungs, resulting in pulmonary fibrosis and compromised immune function. Using single-cell RNA sequencing (scRNA-Seq), our previous studies disclose that CDP exposure triggers heterogeneity of transcriptional profiles in mouse pneumoconiosis, while Vitamin D3 (VitD3) supplementation reduces CDP-induced cytotoxicity; however, the mechanism by which how VitD3 regulates immune status in coal pneumoconiosis remains unclear. In this study, we elucidated the heterogeneity of pulmonary lymphocytes in mice exposed to CDP and demonstrated the therapeutic efficacy of VitD3 using scRNA-Seq dataset. The validation of key lymphocyte markers and their functional molecules was performed using immunofluorescence. The results demonstrated that VitD3 increased the number of naive T cells by modulating CD4 + T cell differentiation and decreased the number of Treg cells in CDP-exposed mice, thereby enhancing the cytotoxic activity of CD8 + effector T cells. These effects markedly alleviated lung fibrosis and symptoms. Taken together, the mechanism by which VitD3 regulates the functions of lymphocytes in CWP provides a new perspective for further research on the prevention and treatment of CWP.

Machine Learning Demonstrates Dominance of Physical Characteristics over Particle Composition in Coal Dust Toxicity

Mine dust has been linked to the development of pneumoconiotic diseases such as silicosis and coal workers' pneumoconiosis. Currently, it is understood that the physicochemical and mineralogical characteristics drive the toxic nature of dust particles; however, it remains unclear which parameter(s) account for the differential toxicity of coal dust. This study aims to address this issue by demonstrating the use of the partial least squares regression (PLSR) machine learning approach to compare the influence of D50 sub 10 μm coal particle characteristics against markers of cellular damage. The resulting analysis of 72 particle characteristics against cytotoxicity and lipid peroxidation reflects the power of PLSR as a tool to elucidate complex particle-cell relationships. By comparing the relative influence of each characteristic within the model, the results reflect that physical characteristics such as shape and particle roughness may have a greater impact on cytotoxicity and lipid peroxidation than composition-based parameters. These results present the first multivariate assessment of a broad-spectrum data set of coal dust characteristics using latent structures to assess the relative influence of particle characteristics on cellular damage.

The role of macrophage polarization and related key molecules in pulmonary inflammation and fibrosis induced by coal dust dynamic inhalation exposure in Sprague-Dawley rats

Coal dust is the main occupational hazard factor during coal mining operations. This study aimed to investigate the role of macrophage polarization and its molecular regulatory network in lung inflammation and fibrosis in Sprague-Dawley rats caused by coal dust exposure. Based on the key exposure parameters (exposure route, dose and duration) of the real working environment of coal miners, the dynamic inhalation exposure method was employed, and a control group and three coal dust groups (4, 10 and 25 mg/m3) were set up. Lung function was measured after 30, 60 and 90 days of coal dust exposure. Meanwhile, the serum, lung tissue and bronchoalveolar lavage fluid were collected after anesthesia for downstream experiments (histopathological analysis, RT-qPCR, ELISA, etc.). The results showed that coal dust exposure caused stunted growth, increased lung organ coefficient and decreased lung function in rats. The expression level of the M1 macrophage marker iNOS was significantly upregulated in the early stage of exposure and was accompanied by higher expression of the inflammatory cytokines TNF-α, IL-1β, IL-6 and the chemokines IL-8, CCL2 and CCL5, with the most significant trend of CCL5 mRNA in lung tissues. Expression of the M2 macrophage marker Arg1 was significantly upregulated in the mid to late stages of coal dust exposure and was accompanied by higher expression of the anti-inflammatory cytokines IL-10 and TGF-β. In conclusion, macrophage polarization and its molecular regulatory network (especially CCL5) play an important role in lung inflammation and fibrosis in SD rats exposed to coal dust by dynamic inhalation.

Prevalence and associations between occupational diseases, emotional exhaustion, and dust mask anxiety among coal miners in Northern China

This study examined the prevalence and associations between occupational-related diseases, emotional exhaustion, and dust mask anxiety among coal miners in Northern China. The study sampled 506 miners from two coal mines in Northern China. Descriptive (frequency, percentages, and chi-square tests) and inferential (complementary log-log logistic regression) analyses were carried out to assess prevalence and associations. The prevalence of coal mining-related pulmonary diseases was 94%, with 40% and 37% reporting pneumoconiosis and bronchitis respectively. Emphysema and tuberculosis were less prevalent with a total prevalence of 5% while 12% of the miners reported two, three, or four of these diseases. For cardiovascular diseases, 66% of the miners reported 3H (hypertension, hyperlipemia, and hyperglycemia) while heart disease and cerebral infarction were reported by 6% and 2% of the miners respectively. Also, 5% and 2% of the miners reported two or all three of 3H, heart condition, and cerebral infarction. The overall prevalence of cardiovascular diseases was 81% while 82% and 63% of the miners reported experiencing some frequency of emotional exhaustion and dust mask anxiety respectively. The study also identified associations between mining-related diseases, emotional exhaustion, dust mask anxiety, and other demographic, personal habits and work-related factors. Miners with pulmonary diseases were more likely to experience emotional exhaustion and dust mask anxiety. Contrariwise, miners with cardiovascular diseases were less likely to experience dust mask anxiety. Factors such as age, engaging in physical exercises, rhinitis, source of pressure and shift system were also associated with emotional exhaustion and dust mask anxiety. These findings highlight the prevalence of occupational diseases, emotional exhaustion, and dust mask anxiety among coal miners in China. The study emphasizes the need for interventions to address health risks, improve work conditions, and support miners' well-being in the coal mining industry.

Nicotine exposure exacerbates silica-induced pulmonary fibrosis via STAT3-BDNF-TrkB-mediated epithelial-mesenchymal transition in alveolar type II cells

The addictive substance nicotine, found in cigarettes and some e-cigarettes, plays a vital role in pro-inflammatory and fibrotic processes. However, the part played by nicotine in the progression of silica-induced pulmonary fibrosis is poorly understood. We used mice exposed to both silica and nicotine to investigate whether nicotine synergizes with silica particles to worsen lung fibrosis. The results revealed that nicotine accelerated the development of pulmonary fibrosis in silica-injured mice by activating STAT3-BDNF-TrkB signalling. Mice with a history of exposure to nicotine showed an increase in Fgf7 expression and alveolar type II cell proliferation if they were also exposed to silica. However, newborn AT2 cells could not regenerate the alveolar structure and release pro-fibrotic factor IL-33. Moreover, activated TrkB induced the expression of p-AKT, which promotes the expression of epithelial-mesenchymal transcription factor Twist, but no Snail. In vitro assessment confirmed activation of the STAT3-BDNF-TrkB pathway in AT2 cells, exposed to nicotine plus silica. In addition, TrkB inhibitor K252a downregulated p-TrkB and the downstream p-AKT and restricted the epithelial-mesenchymal transition caused by nicotine plus silica. In conclusion, nicotine activates the STAT3-BDNF-TrkB pathway, which promotes epithelial-mesenchymal transition and exacerbates pulmonary fibrosis in mice with combined exposure to silica particles and nicotine.

Potential targeted therapy based on deep insight into the relationship between the pulmonary microbiota and immune regulation in lung fibrosis

Pulmonary fibrosis is an irreversible disease, and its mechanism is unclear. The lung is a vital organ connecting the respiratory tract and the outside world. The changes in lung microbiota affect the progress of lung fibrosis. The latest research showed that lung microbiota differs in healthy people, including idiopathic pulmonary fibrosis (IPF) and acute exacerbation-idiopathic pulmonary fibrosis (AE-IPF). How to regulate the lung microbiota and whether the potential regulatory mechanism can become a necessary targeted treatment of IPF are unclear. Some studies showed that immune response and lung microbiota balance and maintain lung homeostasis. However, unbalanced lung homeostasis stimulates the immune response. The subsequent biological effects are closely related to lung fibrosis. Core fucosylation (CF), a significant protein functional modification, affects the lung microbiota. CF regulates immune protein modifications by regulating key inflammatory factors and signaling pathways generated after immune response. The treatment of immune regulation, such as antibiotic treatment, vitamin D supplementation, and exosome micro-RNAs, has achieved an initial effect in clearing the inflammatory storm induced by an immune response. Based on the above, the highlight of this review is clarifying the relationship between pulmonary microbiota and immune regulation and identifying the correlation between the two, the impact on pulmonary fibrosis, and potential therapeutic targets.

Exosomal miRNAs contribute to coal dust particle-induced pulmonary fibrosis in rats

Coal workers' pneumoconiosis (CWP) is a fatal occupational disease caused by inhalation of coal dust particles, which leads to progressive pulmonary fibrosis. Recently, as new signal carriers for intercellular communication, exosomal miRNAs have been validated in the pathogenesis of multiple diseases. However, the research on exosomal miRNAs in CWP is still in the preliminary stage. Here, using miRNA sequencing, exosomal miRNA profiles in bronchoalveolar lavage fluid (BALF) from rats with pulmonary fibrosis induced by coal dust particles were analyzed, and the underlying biological function of putative target genes was explored by GO term analysis and KEGG pathway enrichment analysis. According to the results, intratracheal instillation of coal dust particles can alter the exosomal miRNAs expression in the BALF of rats. Further bioinformatics analysis provided some clues to reveal their function in pathological process of pneumoconiosis. More importantly, we identified 4 differentially expressed exosomal miRNAs (miRNA-21-5p, miRNA-29a-3p, miRNA-26a-5p, and miRNA-34a-5p) by qRT‑PCR and further verified the temporal changes in the expression of these exosomal miRNAs in animal models from 2 weeks to 16 weeks postexposure. In addition, we conducted a preliminary study on Smad7 as a potential target of miRNA-21-5p and found that exosomal miRNA 21-5p/Smad7 may contribute to the pulmonary fibrosis induced by coal dust particles. Our study confirmed the contribution of exosomal miRNAs to coal dust particle-induced pulmonary fibrosis and provided new insights into the pathogenesis of CWP.

Understanding the pathogenesis of occupational coal and silica dust-associated lung disease

Workers in the mining and construction industries are at increased risk of respiratory and other diseases as a result of being exposed to harmful levels of airborne particulate matter (PM) for extended periods of time. While clear links have been established between PM exposure and the development of occupational lung disease, the mechanisms are still poorly understood. A greater understanding of how exposures to different levels and types of PM encountered in mining and construction workplaces affect pathophysiological processes in the airways and lungs and result in different forms of occupational lung disease is urgently required. Such information is needed to inform safe exposure limits and monitoring guidelines for different types of PM and development of biomarkers for earlier disease diagnosis. Suspended particles with a 50% cut-off aerodynamic diameter of 10 µm and 2.5 µm are considered biologically active owing to their ability to bypass the upper respiratory tract's defences and penetrate deep into the lung parenchyma, where they induce potentially irreversible damage, impair lung function and reduce the quality of life. Here we review the current understanding of occupational respiratory diseases, including coal worker pneumoconiosis and silicosis, and how PM exposure may affect pathophysiological responses in the airways and lungs. We also highlight the use of experimental models for better understanding these mechanisms of pathogenesis. We outline the urgency for revised dust control strategies, and the need for evidence-based identification of safe level exposures using clinical and experimental studies to better protect workers' health.

Glycogen metabolism reprogramming promotes inflammation in coal dust-exposed lung

Long-term coal dust exposure triggers complex inflammatory processes in the coal workers' pneumoconiosis (CWP) lungs. The progress of the inflammation is reported to be affected by disordered cell metabolism. However, the changes in the metabolic reprogramming associated with the pulmonary inflammation induced by the coal dust particles are unknown. Herein, we show that coal dust exposure causes glycogen accumulation and the reprogramming of glucose metabolism in the CWP lung. The glycogen accumulation caused by coal dust is mainly due to macrophages, which reprogram glycogen metabolism and trigger an inflammatory response. In addition, 2-deoxy-D-glucose (2-DG) reduced glycogen content in macrophages, which was accompanied by mitigated inflammation and restrained NF-κB activation. Accordingly, we have pinpointed a novel and crucial metabolic pathway that is an essential regulator of the inflammatory phenotype of coal dust-exposed macrophages. These results shed light on new ways to regulate CWP inflammation.

Inflammation and fibrosis in the coal dust-exposed lung described by confocal Raman spectroscopy

Background

Coal workers' pneumoconiosis (CWP) is an occupational disease that severely damages the life and health of miners. However, little is known about the molecular and cellular mechanisms changes associated with lung inflammation and fibrosis induced by coal dust. As a non-destructive technique for measuring biological tissue, confocal Raman spectroscopy provides accurate molecular fingerprints of label-free tissues and cells. Here, the progression of lung inflammation and fibrosis in a murine model of CWP was evaluated using confocal Raman spectroscopy.

Methods

A mouse model of CWP was constructed and biochemical analysis in lungs exposed to coal dust after 1 month (CWP-1M) and 3 months (CWP-3M) vs control tissues (NS) were used by confocal Raman spectroscopy. H&E, immunohistochemical and collagen staining were used to evaluate the histopathology alterations in the lung tissues.

Results

The CWP murine model was successfully constructed, and the mouse lung tissues showed progression of inflammation and fibrosis, accompanied by changes in NF-κB, p53, Bax, and Ki67. Meanwhile, significant differences in Raman bands were observed among the different groups, particularly changes at 1,248, 1,448, 1,572, and 746 cm^-1. These changes were consistent with collagen, Ki67, and Bax levels in the CWP and NS groups.

Conclusion

Confocal Raman spectroscopy represented a novel approach to the identification of the biochemical changes in CWP lungs and provides potential biomarkers of inflammation and fibrosis.

Geochemical and Morphological Evaluations of Organic and Mineral Aerosols in Coal Mining Areas: A Case Study of Santa Catarina, Brazil

Numerous researchers have described the correlation between the short-term contact of nano-particulate (NP) matter in diverse coal phases and amplified death or hospitalizations for breathing disorders in humans. However, few reports have examined the short-term consequences of source-specific nanoparticles (NPs) on coal mining areas. Advanced microscopic techniques can detect the ultra-fine particles (UFPs) and nanoparticles that contain potential hazardous elements (PHEs) generated in coal mining areas. Secondary aerosols that cause multiple and complex groups of particulate matter (PM10, PM2.5, PM1) can be collected on dry deposition. In this study, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) were employed to detect and define the magnitude of particulate matters on restaurants walls at coal mines due to weathering interactions. The low cost self-made passive sampler (SMPS) documented several minerals and amorphous phases. The results showed that most of the detected coal minerals exist in combined form as numerous complexes comprising significant elements (e.g., Al, C, Fe, K, Mg, S, and Ti), whereas others exist as amorphous or organic compounds. Based on the analytical approach, the study findings present a comprehensive understanding of existing potential hazardous elements in the nanoparticles and ultrafine particles from coal mining areas in Brazil.