BMAL1/p53 mediating bronchial epithelial cell autophagy contributes to PM2.5-aggravated asthma

Fudosteine attenuates lung inflammation in mice with PM2.5-induced asthma exacerbation by inhibiting pyroptosis via the NLRP3/caspase-1/GSDMD pathway

This study aimed to explore the potential preventive effects of fudosteine (Fud) on PM2.5-induced asthma exacerbations in a murine model. BALB/c mice were randomly allocated into six groups: control, Fud, ovalbumin (OVA), OVA+Fud, OVA+PM2.5, and OVA+PM2.5 + Fud. An asthma model was established through OVA sensitization and challenge. Compared to the OVA group, PM2.5 exposure exacerbated allergic asthma, as evidenced by increased collagen fiber deposition, goblet cell metaplasia, mucus secretion, heightened airway inflammation, elevated total cell and eosinophil counts, and upregulated levels of interleukin (IL)-1β, IL-18, and NLRP3 expression in lung tissues. Notably, fudosteine treatment mitigated these pathological changes. Western blot analysis revealed that fudosteine significantly reduced the expression of NLRP3, caspase-1, gasdermin D (GSDMD), cleaved-caspase-1, and cleaved-GSDMD in lung tissues. In conclusion, fudosteine alleviated lung inflammation, collagen deposition, and mucus secretion in PM2.5-induced asthma exacerbation, potentially by inhibiting the NLRP3 inflammasome-mediated pyroptosis pathway.

Analysis of Pediatric Acute Upper Airway Pathology During Local Wildfires and Increased PM 2.5 Burden

OBJECTIVE

As wildfires worldwide increase in severity and frequency, fine particulate matter (PM 2.5), generated as a component of wildfire smoke, increasingly impacts air quality. Children are particularly vulnerable to poor air quality in numerous ways, including inhalation of more air in proportion to their body size than adults. Though its adverse impacts on the lower airway are well demonstrated, the clinical effects of PM 2.5 on the pediatric upper airway are poorly understood and warrant investigation.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary academic medical center.

METHODS

From 2014 to 2023, patient presentations to a pediatric emergency department in Northern California during exposure periods of elevated PM 2.5 burden associated with nearby wildfires were identified. Patient diagnoses, presenting symptoms, and management were analyzed. Comparison group patients were evaluated during date-matched control periods with confirmed normal air quality. Chi-squared analyses determined significance.

RESULTS

During periods of increased wildfire-generated PM 2.5 burden, a significantly greater proportion of pediatric patients presented to the emergency department with upper airway pathology compared to matched control periods of healthy air quality. Further, a significantly greater proportion of patients were diagnosed with croup during wildfires. Of patients presenting with upper airway pathology, a significantly greater proportion experienced dysphonia during wildfires and had a negative strep test.

CONCLUSION

Wildfire-generated PM 2.5 may contribute to increased rates of croup presentations, and PM 2.5 may disproportionately affect the larynx in the pediatric upper airway. Larger population-based studies and preclinical models may clarify these clinical manifestations of a growing public health threat.

PERK/Sestrin2 Signaling Pathway Mediated Autophagy Regulates Human Cardiomyocytes Apoptosis Induced by Traffic-Related PM2.5 and Diverse Constituents

Although the strong causal association between PM2.5 and cardiovascular disease has been extensively studied, the latent molecular mechanisms have not been entirely explained. The objective of this research was to assess the cardiotoxicity of Traffic-related PM2.5 (TRPM2.5), water-soluble components (WSC), and water-insoluble components (WIC) in human cardiomyocytes (AC16) and to investigate the underlying molecular mechanisms. Endoplasmic reticulum stress (ERS), autophagy, and apoptosis were activated 24 h after exposure to total-TRPM2.5, WSC, or WIC. WIC was predominantly related to cardiotoxicity compared to WSC. Sestrin2 is an upstream molecule in several signaling pathways, including those involved in autophagy and apoptosis. In this study, we found that the knockdown of Protein Kinase RNA-like Endoplasmic Reticulum Kinase (PERK) suppressed the expression of PERK, Sestrin2, Caspase-12, Caspase-3, LC3, and p62 in TRPM2.5-treated AC16 cells. These results indicate that ERS participates in the activation of autophagy and apoptosis through the PERK/Sestrin2 pathway. We found that inhibiting autophagy with 3-methyladenine (3-MA) decreased the expression of autophagy-related factors and aggravated apoptosis. These observations suggest that protective autophagy was initiated. Finally, our findings provide valuable insights into the molecular mechanism by which ERS might regulate autophagy through the PERK/Sestrin2 signaling pathway, and protective autophagy may be activated to relieve TRPM2.5 and component-mediated apoptosis in AC16 cells.

The Common Hallmarks and Interconnected Pathways of Aging, Circadian Rhythms, and Cancer: Implications for Therapeutic Strategies

The intricate relationship between cancer, circadian rhythms, and aging is increasingly recognized as a critical factor in understanding the mechanisms underlying tumorigenesis and cancer progression. Aging is a well-established primary risk factor for cancer, while disruptions in circadian rhythms are intricately associated with the tumorigenesis and progression of various tumors. Moreover, aging itself disrupts circadian rhythms, leading to physiological changes that may accelerate cancer development. Despite these connections, the specific interplay between these processes and their collective impact on cancer remains inadequately explored in the literature. In this review, we systematically explore the physiological mechanisms of circadian rhythms and their influence on cancer development. We discuss how core circadian genes impact tumor risk and prognosis, highlighting the shared hallmarks of cancer and aging such as genomic instability, cellular senescence, and chronic inflammation. Furthermore, we examine the interplay between circadian rhythms and aging, focusing on how this crosstalk contributes to tumorigenesis, tumor proliferation, and apoptosis, as well as the impact on cellular metabolism and genomic stability. By elucidating the common pathways linking aging, circadian rhythms, and cancer, this review provides new insights into the pathophysiology of cancer and identifies potential therapeutic strategies. We propose that targeting the circadian regulation of cancer hallmarks could pave the way for novel treatments, including chronotherapy and antiaging interventions, which may offer important benefits in the clinical management of cancer.

PM2.5 exposure deteriorates Th1/Th2 balance in pediatric asthma by downregulating ALKBH5 and enhancing SRSF1 m6A methylation

Accumulating evidence has shown that long-term exposure to particulate matter with aerodynamic diameter of less than 2.5 μm (PM2.5) causes Th1/Th2 imbalance and increases the risk of allergic asthma (AA) in children. However, the mechanism underlying such effect remains elusive. Here, an AA mouse model was developed by intranasal administration of ovalbumin (OVA) and uncovered that OVA-sensitized mice exhibited pathological damage of lung tissues, mucus production, augmented serum IgE levels, enhanced Th2 cells and associated cytokine levels, and diminished Th1 cells and associated cytokine levels. Meanwhile, OVA induction led to upregulation of SRSF1 in mice. Moreover, shRNA-mediated knockdown of SRSF1 suppressed AA and Th1/Th2 imbalance in OVA-sensitized mice. After PM2.5 exposure, AA and Th1/Th2 imbalance were exacerbated and SRSF1 expression was increased in OVA-sensitized mice. Mechanistic experiments demonstrated that PM2.5-mediated inhibition of ALKBH5 expression augmented SRSF1 m6A modification in human bronchial epithelial cells treated with house dust mite. In this process, the m6A-reading protein YTHDF1 bound to SRSF1 mRNA and increased its stability. Furthermore, ALKBH5 overexpression neutralized PM2.5-aggravated Th1/Th2 imbalance in OVA-sensitized mice. Altogether, PM2.5 fosters Th1/Th2 imbalance in pediatric asthma by increasing SRSF1 m6A methylation through ALKBH5 downregulation.

Midkine, a novel MCP-1 activator mediated PM2.5-aggravated experimental pulmonary fibrosis

Exposure to fine particulate matter (PM2.5) is associated with increased morbidity and mortality among patients with idiopathic pulmonary fibrosis (IPF). Pathological alterations in IPF typically originate in the subpleural regions of the lungs. However, it was unclear how PM2.5 affected subpleural pulmonary fibrosis. In this study, atmospheric PM2.5 and carbon blacks were utilized as representative particulate matter to investigate these effects. Mouse models and cell models were made to investigate macrophage chemotaxis changes under PM2.5 exposure in vivo and in vitro. The findings indicated that PM2.5 promoted macrophage aggregation in the subpleural region of lung and aggravated bleomycin-induced pulmonary fibrosis in mice. At the same time, we uncovered for the first time that PM2.5 exposure led to an upregulation of midkine, which subsequently enhanced the production of monocyte chemotactic protein-1 (MCP-1) through the cell surface receptor Syndecan 4 (SDC4) in pleural mesothelial cells (PMCs), thereby, inducing macrophage aggregation in subpleural region of lung. Furthermore, our results indicated that PM2.5 and bleomycin facilitated macrophage M1 polarization and the production of profibrotic inflammatory factors, culminating in fibrotic alterations in PMCs, lung fibroblasts, and alveolar epithelial cells. Finally, we demonstrated that inhibition of midkine ameliorated lung function and mitigated pulmonary fibrosis in vivo. In conclusion, our findings elucidated that midkine acted as a novel MCP-1 activator, mediating PM2.5-aggravated experimental pulmonary fibrosis, and suggested that the midkine/SDC4/MCP-1 signal should be a new therapeutic target for the treatment of PM2.5-related IPF.

Therapeutic Evaluation of Wumei Pill (WP) for Nocturnal Asthma in Bmal1 Gene Knockout Mice

OBJECTIVE

Previous clinical studies have demonstrated that Wumei Pill (WP), a traditional Chinese medicine formula, can effectively alleviate nocturnal asthma-related anxiety and improve nighttime symptoms. The therapeutic mechanism of WP may involve regulation of inflammatory chemokines in peripheral blood. This mechanism is potentially linked to modulation of the circadian clock gene ARNT-like protein-1 (Bmal1), but precise pathways underlying this interaction remain unclear, requiring further investigation.

METHODS

Bmal1 knockout and wild-type mice were utilized to establish asthma models. Techniques such as flow cytometry, RT-PCR, and ELISA were employed to measure the levels of serum inflammatory mediators, specifically IFN-γ, CXCL16, I-TAC, and PARC. Furthermore, the pathological alterations in airway thickness were assessed. Additionally, we investigated the regulation of the Bmal1 gene and its influence on the circadian rhythm-related recruitment of leukocytes, as well as the expression patterns of downstream mediators.

RESULTS

Compared to the wild-type (WT) group, the model group showed significantly higher levels of CXCL16, I-TAC, and PARC (p < 0.05), as well as a notable decrease in IFN-γ expression. WP treatment effectively normalized the levels of these inflammatory factors in the model group, indicating a regulatory effect of WP on inflammatory chemokines.

CONCLUSION

The knockout of the Bmal1 gene, a crucial regulator of circadian rhythms, disrupts the circadian expression of inflammatory chemokines. Treatment with WP modulated Bmal1 expression, influencing the release of these mediators, offering a promising strategy for managing nocturnal asthma. Notably, wild-type nocturnal asthma mice exhibited significantly better control of airway inflammation compared to their Bmal1-deficient counterparts, highlighting the importance of circadian regulation in the pathophysiology of asthma.

Lung proteomic and metabolomic changes induced by carbon black nanoparticles and high humidity in a mouse asthma model

Allergic asthma is a significant international concern in respiratory health, which can be exacerbated by the increasing levels of non-allergenic pollutants. This rise in airborne pollutants is a primary driver behind the growing prevalence of asthma, posing a health emergency. Additionally, climatic risk factors can contribute to the onset and progression of asthma. Understanding the complex interplay between pollution, climate, and asthma induction is crucial to elucidate how environmental changes intensify asthma. In this study, we investigated the proteomic and metabolomic changes in the lungs of a mouse asthma model following co-exposure to carbon black nanoparticles and high humidity, which represent airborne and climatic factors, respectively. An asthma model was established using ovalbumin, and mice were intratracheally instilled with 15 or 30 μg/kg of carbon black and simultaneously exposed to either 70% or 90% relative humidity. Protein and metabolite profiles from the lung were used to analyze the most significantly changed clusters, and potential biomarkers and enriched pathways were identified to dissect the adverse effects of the two risk factors. The lung proteome and metabolome are significantly altered by the co-exposure, with the effects modulated by carbon black concentration and humidity level. This study proposes 10 proteins and 18 metabolites as candidate biomarkers. The significantly enriched KEGG pathways include one protein pathway (primary immunodeficiency) and six metabolic pathways (ABC transporters, nucleotide metabolism, Parkinson's disease, purine metabolism, choline metabolism in cancer, and biosynthesis of cofactors). A joint proteomic and metabolomic analysis identifies five common pathways across both omics, namely, ABC transporters, central carbon metabolism in cancer, EGFR tyrosine kinase inhibitor resistance, glioma, and NF-kappa B signaling pathway, disturbed by the co-exposure. We provide a multi-omic basis for the health risk assessment and management of co-exposures to environmental risk factors.

Efficacy and mechanism of Qianjinweijing Decoction for asthma: Integrating systematic review with meta-analysis and network pharmacology

BACKGROUND

Asthma seriously affects people's survival and quality of life, causing a huge economic burden on society. Modern clinical use of Qianjinweijing Decoction (QJWJ) for the treatment of asthma has achieved good results. However, there is still a lack of research on its efficacy and mechanism of action. Therefore, the purpose of this study is to evaluate the efficacy of QJWJ in the treatment of asthma by systematic review and meta-analysis, and to explore its potential mechanism by network pharmacology.

METHODS

The meta-analysis was performed to search for studies published before May 2023 in 7 databases, and Revman 5.4 and R language softwares were used for analysis. Network pharmacology was based on open databases and softwares such as Cytoscape, Perl, Autoduck Vina, and R language.

RESULTS

A total of 14 studies were included, involving 1200 patients. The results of the meta-analysis showed that QJWJ could significantly improve the clinical efficacy of asthma patients compared with routine pharmacotherapy (risk ratio = 1.22, 95% CI [1.16, 1.28], P < .00001), enhance lung function, such as FEV1/FVC (mean difference [MD] = 5.63, 95% CI [1.45, 9.81], P = .008), FEV1% (MD = 5.03, 95% CI [4.32, 5.74], P < .00001), PEF (standardized mean difference = 1.37, 95% CI [1.03, 1.71], P < .00001), and increase traditional Chinese medicine syndrome score (MD = -2.50, 95% CI [-4.81, -0.19], P = .03). The results of network pharmacology suggested that the 4 traditional Chinese medicines in QJWJ included 35 active ingredients and 34 potential targets for the treatment of asthma. The core ingredients involved were stigmasterol, β-sitosterol, hederagenin, and gibberellin 7. The core targets were PTGS2, BCL2, and CASP3. The interaction pathway between QJWJ and asthma was mainly enriched in p53, cyclic guanosine monophosphate-protein kinase G, IL-17, and advanced glycation end products-receptor for advanced glycation end products signaling pathways. Molecular docking showed that the core ingredients had good binding activity with the core targets.

CONCLUSION

QJWJ is effective in the treatment of asthma, and the therapeutic mechanism may be related to its regulation of inflammation, immunity, and apoptosis.

Ambient fine particulate matter provokes multiple modalities of cell death via perturbation of subcellular structures

Fine particulate matter (PM2.5) is increasingly recognized for its detrimental effects on human health, with substantial evidence linking exposure to various forms of cell death and dysfunction across multiple organ systems. This review examines key cell death mechanisms triggered by PM2.5, including PANoptosis, necroptosis, autophagy, and ferroptosis, while other forms such as oncosis, paraptosis, and cuprotosis remain unreported in relation to PM2.5 exposure. Mitochondria, endoplasmic reticulum, and lysosomes emerge as pivotal organelles in the disruption of cellular homeostasis, with mitochondrial dysfunction particularly implicated in metabolic dysregulation and the activation of pro-apoptotic pathways. Although PM2.5 primarily affects the nucleus, cytoskeleton, mitochondria, endoplasmic reticulum, and lysosomes, other organelles like ribosomes, Golgi apparatus, and peroxisomes have received limited attention. Interactions between these organelles, such as endoplasmic reticulum-associated mitochondrial membranes, lysosome-associated mitophagy, and mitochondria-nuclei retro-signaling may significantly contribute to the cytotoxic effects of PM2.5. The mechanisms of PM2.5 toxicity, encompassing oxidative stress, inflammatory responses, and metabolic imbalances, are described in detail. Notably, PM2.5 activates the NLRP3 inflammasome, amplifying inflammatory responses and contributing to chronic diseases. Furthermore, PM2.5 exposure disrupts genetic and epigenetic regulation, often resulting in cell cycle arrest and exacerbating cellular damage. The composition, concentration, and seasonal variability of PM2.5 modulate these effects, underscoring the complexity of PM2.5-induced cellular dysfunction. Despite significant advances in understanding these pathways, further research is required to elucidate the long-term effects of chronic PM2.5 exposure, the role of epigenetic regulation, and potential strategies to mitigate its harmful impact on human health.

DEC1 is involved in circadian rhythm disruption-exacerbated pulmonary fibrosis

BACKGROUND

The alveolar epithelial type II cell (AT2) and its senescence play a pivotal role in alveolar damage and pulmonary fibrosis. Cell circadian rhythm is strongly associated with cell senescence. Differentiated embryonic chondrocyte expressed gene 1 (DEC1) is a very important circadian clock gene. However, the role of DEC1 in AT2 senescence and pulmonary fibrosis was still unclear.

RESULTS

In this study, a circadian disruption model of light intervention was used. It was found that circadian disruption exacerbated pulmonary fibrosis in mice. To understand the underlying mechanism, DEC1 levels were investigated. Results showed that DEC1 levels increased in lung tissues of IPF patients and in bleomycin-induced mouse fibrotic lungs. In vitro study revealed that bleomycin and TGF-β1 increased the expressions of DEC1, collagen-I, and fibronectin in AT2 cells. Inhibition of DEC1 mitigated bleomycin-induced fibrotic changes in vitro and in vivo. After that, cell senescence was observed in bleomycin-treated AT2 cells and mouse models, but these were prevented by DEC1 inhibition. At last, p21 was confirmed having circadian rhythm followed DEC1 in normal conditions. But bleomycin disrupted the circadian rhythm and increased DEC1 which promoted p21 expression, increased p21 mediated AT2 senescence and pulmonary fibrosis.

CONCLUSIONS

Taken together, circadian clock protein DEC1 mediated pulmonary fibrosis via p21 and cell senescence in alveolar epithelial type II cells.

Knockdown of KIF23 alleviates the progression of asthma by inhibiting pyroptosis

BACKGROUND

Asthma is a chronic disease affecting the lower respiratory tract, which can lead to death in severe cases. The cause of asthma is not fully known, so exploring its potential mechanism is necessary for the targeted therapy of asthma.

METHOD

Asthma mouse model was established with ovalbumin (OVA). H&E staining, immunohistochemistry and ELISA were used to detect the inflammatory response in asthma. Transcriptome sequencing was performed to screen differentially expressed genes (DEGs). The role of KIF23 silencing in cell viability, proliferation and apoptosis was explored by cell counting kit-8, EdU assay and flow cytometry. Effects of KIF23 knockdown on inflammation, oxidative stress and pyroptosis were detected by ELISA and western blot. After screening KIF23-related signalling pathways, the effect of KIF23 on p53 signalling pathway was explored by western blot.

RESULTS

In the asthma model, the levels of caspase-3, IgG in serum and inflammatory factors (interleukin (IL)-1β, KC and tumour necrosis factor (TNF)-α) in serum and bronchoalveolar lavage fluid were increased. Transcriptome sequencing showed that there were 352 DEGs in the asthma model, and 7 hub genes including KIF23 were identified. Knockdown of KIF23 increased cell proliferation and inhibited apoptosis, inflammation and pyroptosis of BEAS-2B cells induced by IL-13 in vitro. In vivo experiments verified that knockdown of KIF23 inhibited oxidative stress, inflammation and pyroptosis to alleviate OVA-induced asthma mice. In addition, p53 signalling pathway was suppressed by KIF23 knockdown.

CONCLUSION

Knockdown of KIF23 alleviated the progression of asthma by suppressing pyroptosis and inhibited p53 signalling pathway.

Effects of PM2.5 exposure on clock gene BMAL1 and cell cycle in human umbilical vein endothelial cells

Background

Fine particulate matter (PM2.5) exposure has been closely associated with cardiovascular diseases, which are relevant to cell cycle arrest. Brain and muscle aryl-hydrocarbon receptor nuclear translocator-like protein 1 (BMAL1) not only participates in regulating the circadian clock but also plays a role in modulating cell cycle. However, the precise contribution of the circadian clock gene BMAL1 to PM2.5-induced cell cycle change remains unclear. This study aims to explore the impact of PM2.5 exposure on BMAL1 expression and the cell cycle in human umbilical vein endothelial cells (HUVECs).

Methods

HUVECs was exposed to PM2.5 for 24 hours at different concentrations ((0, 12.5, 25, 75 and 100 μg.mL-1) to elucidate the potential toxic mechanism. Following exposure to PM2.5, cell viability, ROS, cell cycle, and the expression of key genes and proteins were detected.

Results

A remarkable decrease in cell viability is observed in the PM2.5-exposed HUVECs, as well as a significant increase in ROS production. In addition, PM2.5-exposed HUVECs have cycle arrest in G0/G1 phase, and the gene expression of p27 is also markedly increased. The protein expression of BMAL1 and the gene expression of BMAL1 are increased significantly. Moreover, the protein expressions of p-p38 MAPK and p-ERK1/2 exhibit a marked increase in the PM2.5-exposed HUVECs. Furthermore, following the transfection of HUVECs with siBMAL1 to suppress BMAL1 expression, we observed a reduction in both the protein and gene expression of the MAPK/ERK pathway in HUVECs exposed to PM2.5.

Conclusions

Overall, our results indicate that PM2.5 exposure significantly upregulates the circadian clock gene expression of BMAL1 and regulates G0/G1 cell cycle arrest in HUVECs through the MAPK/ERK pathway, which may provide new insights into the potential molecular mechanism regarding BMAL1 on PM2.5-induced cardiovascular diseases.