PM2.5 induces pulmonary microvascular injury in COPD via METTL16-mediated m6A modification

Big picture thinking of global PM2.5-related COPD: Spatiotemporal trend, driving force, minimal burden and economic loss

Chronic obstructive pulmonary disease (COPD) is a leading global cause of morbidity and mortality, with increasing evidence linking long-term exposure to ambient fine particulate matter (PM2.5) to accelerated lung function decline and exacerbation of COPD symptoms. This study aimed to assess the global burden of PM2.5-related COPD from 1990 to 2021 and project future health and economic impacts. Using Mendelian randomization, the causal relationship between PM2.5 exposure and COPD was confirmed. Data from the Global Burden of Disease 2021 dataset was analyzed across 204 countries, considering age, gender, region, and socio-demographic index (SDI). A significant positive correlation between PM2.5 exposure and COPD was observed. In 2021, COPD deaths due to ambient PM2.5 exposure reached 841,466 globally, with an age-standardized mortality rate (ASR) of 10.23 per 100,000 people. DALYs were 17,683,776, with an ASR of 208.27 per 100,000. Both the number of deaths and DALYs significant increased since 1990, primarily driven by population aging and growth. Regional analysis revealed that Asia, especially China and India, bore the highest burden, high SDI regions managed to maintain relatively stable and lower rates, and there are large health inequities. Projections indicate a continued rise in COPD burden, with substantial economic implications, estimating global economic losses of approximately $1.246 trillion by 2050. These findings highlighted the urgent need for public health interventions to mitigate future health and economic impacts of PM2.5 exposure.

Curcumin Modulates the PTEN/PI3K/AKT Pathway to Alleviate Inflammation and Oxidative Stress in PM2.5-Induced Chronic Obstructive Pulmonary Disease

Ambient fine particulate matter (PM2.5) contributes to the onset and escalation of chronic obstructive pulmonary disease (COPD) through the induction of inflammatory reactions and oxidative stress. Curcumin is a natural polyphenolic compound renowned for the potent antioxidant and anti-inflammatory properties. This research utilized a PM2.5-induced COPD mouse model and BEAS-2B cell line to explore the protective mechanisms of curcumin. The results showed that PM2.5 impaired pulmonary function, exacerbated airway inflammation, and caused structural damage to lung tissue. Elevated levels of inflammatory cytokines such as IL-6, IL-1β, and TNF-α, increased malondialdehyde, and reduced activities of antioxidant enzymes catalase and superoxide dismutase were observed in both mice and BEAS-2B cell line. PM2.5 exposure also suppressed PTEN expression and activated PI3K/AKT signal, and the downstream molecule NF-κB was activated and FoxO1 activity was inhibited. PTEN overexpression partially reversed PM2.5-induced inflammation and oxidative stress in vitro. Curcumin enhanced PTEN expression, inhibited PI3K/AKT and NF-κB activation, and restored FoxO1 activity, alleviating airway inflammation and oxidative stress, while PTEN inhibition attenuated the ameliorating effects of curcumin in vitro and in vivo. In summary, PM2.5 exposure induces COPD inflammation and oxidative stress by disrupting PTEN/PI3K/AKT signaling and curcumin significantly alleviates these effects partially through PTEN/PI3K/AKT signal.

WTAP-mediated m6A modification of Hmgb2 contributes to spermatogenic damage induced by PM2.5 exposure

N6-methyladenosine (m6A) is extensively involved in complex spermatogenesis while being extremely sensitive to environmental exposure. Numerous studies have revealed the toxicity of fine particulate matter (PM2.5) to the male reproductive system, but the specific epigenetic mechanisms involved have been underexplored. Here, we investigated the effect of m6A modification on PM2.5-induced male reproductive impairment by establishing a real-time PM2.5-exposed mouse model and a GC-2spd cell model. PM2.5 exposure resulted in damage to the spermatogenic epithelium and mitochondrial abnormalities in spermatocytes and significantly reduced sperm motility in mice. Gene enrichment analyses of testicular tissue differential m6A modified genes were significantly enriched to spermatogenesis in the PM2.5-treated mice compared with the control group, and the expression of the methylase WTAP was markedly decreased after PM2.5 exposure. Moreover, PM2.5 exposure resulted in a significant reduction in the expression of the spermatogenesis-related gene Hmgb2, as well as in the level of the Hmgb2 m6A modification. Transcriptome sequencing and verification experiments suggested that Hmgb2 may regulate spermatocyte ATP levels. In addition, we demonstrated that the m6A methylase WTAP affects Hmgb2 mRNA stability via m6A modification. Our study provides new insights into PM2.5-induced damage to spermatogenesis and reduced sperm motility.

Fine Particulate Matter (PM2.5) and the Blood-Testis Barrier: An in Vivo and in Vitro Mechanistic Study

BACKGROUND

Fine particulate matter [particulate matter (PM) with aerodynamic diameter of ≤ 2.5 μ m (PM 2.5 )] is considered a major component of ambient PM. Exposure to PM 2.5 was shown to be associated with male reproductive system injury. Ferroptosis is regarded as an iron-dependent programmed cell death that is associated with the pathological process. It has been reported that SIRT1 has protective effects on the male reproductive system. However, the underlying mechanisms of exposure to PM 2.5 -induced testicular injury are still unexplored.

OBJECTIVES

In this study, we investigated the relationship between ferroptosis and male reproductive injury after exposure to PM 2.5 and the role of SIRT1/HIF-1 α signaling pathway in this process.

METHODS

We established a PM 2.5 exposure model in vivo and in vitro using Sertoli cell Sirt1 conditional knockout C57BL/6 (cKO) mice testes and primary Sertoli cells. Hematoxylin and eosin (H&E) staining were conducted to examine the histology of the mice testes. Sperm parameters and biotin tracer assay were conducted to evaluate the effects of exposure to PM 2.5 on the mice testes. Related markers and genes related to the blood-testis barrier (BTB) and ferroptosis were measured by quantitative real-time polymerase chain reaction (qPCR), western blot, and immunofluorescence assay. siRNA transfection was used to evaluate the potential mechanism.

RESULTS

Significant pathological damage and lower sperm quality were detected in mice testes exposed to PM 2.5 . We found that exposure to PM 2.5 damaged the BTB and inhibited the expression level of the BTB-related proteins (including Connexin 43, Occludin, Claudin 11, N-Cadherin and ZO-1). According to the enrichment analysis results, ferroptosis and HIF-1 α signaling pathway were significantly enriched in mice testes and primary Sertoli cells exposed to PM 2.5 . Subsequent experiments were conducted to verify the results of the enrichment analysis and revealed differences in the expression levels of HIF-1 α , ferroptosis-related genes (including GPX4, SLC7A11, ACSL4, and HO-1) and ferroptosis-related markers [including malondialdehyde (MDA), glutathione (GSH), and Fe 2 + ], associated with lower expression of SIRT1 after exposure to PM 2.5 . These results suggest that PM 2.5 exposure may be associated with ferroptosis and HIF-1 α signaling pathway in male reproductive dysfunction.

CONCLUSIONS

Taken together, in vivo and in vitro experiments verified that PM 2.5 exposure in mice may lead to testicular dysfunction through new pathways. https://doi.org/10.1289/EHP14447.

Transcriptome-Wide Analysis of N6-Methyladenosine-Modified Long Noncoding RNAs in Particulate Matter-Induced Lung Injury

BACKGROUND

N6-methyladenosine (m6A) modification plays a crucial role in the regulation of diverse cellular processes influenced by environmental factors. Nevertheless, the involvement of m6A-modified long noncoding RNAs (lncRNAs) in the pathogenesis of lung injury induced by particulate matter (PM) remains largely unexplored.

METHODS

Here, we establish a mouse model of PM-induced lung injury. We utilized m6A-modified RNA immunoprecipitation sequencing (MeRIP-seq) to identify differentially expressed m6A peaks on long non-coding RNAs (lncRNAs). Concurrently, we performed lncRNA sequencing (lncRNA-seq) to determine the differentially expressed lncRNAs. The candidate m6A-modified lncRNAs in the lung tissues of mice were identified through the intersection of the data obtained from these two sequencing approaches.

RESULTS

A total of 664 hypermethylated m6A peaks on 644 lncRNAs and 367 hypomethylated m6A peaks on 358 lncRNAs are confirmed. We use bioinformatic tools to analyze the potential functions and pathways of these m6A-modified lncRNAs, revealing their involvement in regulating inflammation, immune response, and metabolism-related pathways. Three key m6A-modified lncRNAs (lncRNA NR_003508, lncRNA uc008scb.1, and lncRNA ENSMUST00000159072) are identified through a joint analysis of the MeRIP-seq and lncRNA-seq data, and their validation is carried out using MeRIP-PCR and qRT-PCR. Analysis of the coding-non-coding gene co-expression network reveals that m6A-modified lncRNAs NR_003508 and uc008scb.1 participate in regulating pathways associated with inflammation and immune response.

CONCLUSIONS

This study first provides a comprehensive transcriptome-wide analysis of m6A methylation profiling in lncRNAs associated with PM-induced lung injury and identifies three pivotal candidate m6A-modified lncRNAs. These findings shed light on a novel regulatory mechanism underlying PM-induced lung injury.

METTL16 controls airway inflammations in smoking-induced COPD via regulating glutamine metabolism

The persistent airway inflammation is the main characteristic of chronic obstructive pulmonary disease (COPD), typically caused by an indoor environment pollution cigarette smoke (CS). METTL16 is an m6A methyltransferase that has been proven to be closely associated with the occurrence of various diseases. However, its exact role in smoking-induced COPD remains to be investigated. In this study, we found that the level of METTL16 was aberrantly decreased in lung tissues of COPD smokers. Similarly, murine model induced by CS and lung epithelial cell model induced by cigarette smoke extract (CSE) also confirmed this discovery. Moreover, in the Mettl16-deficient (Mettl16+/-) mice challenged with CS, airway inflammation was aggravated. To identify the potential target genes and regulatory pathways through METTL16, methylated RNA immunoprecipitation sequencing (meRIP-seq), RNA sequencing (RNA-seq) and metabolomic profiling were used. Knockdown of METTL16 significantly reduced the stability of glutamic-oxaloacetic transaminase 2 (GOT2) and downregulated its expression through m6A modification, while reprogramed glutamine metabolism in lung epithelial cells. Significant reduction in inflammation levels was observed in the 3-month COPD murine model fed a glutamine-supplemented diet. Mechanistically, METTL16 could regulate lung epithelial mitochondrial function by participating in the reprogramming of glutamine metabolism. Our study characterized the role of the METTL16/GOT2/glutamine axis in the occurrence and development of COPD, and emphasized the potential value of METTL16 and glutamine in the therapy of chronic airway inflammation in smoking-induced COPD.

Fine particulate matter‑induced cardiac developmental toxicity (Review)

Fine particulate matter (PM2.5) has become an important risk factor threatening human health. Epidemiological and toxicological investigations have revealed that PM2.5 not only leads to cardiovascular dysfunction, but it also gives rise to various adverse health effects on the human body, such as cardiovascular and cerebrovascular diseases, cancers, neurodevelopmental disorders, depression and autism. PM2.5 is able to penetrate both respiratory and placental barriers, thereby resulting in negative effects on fetal development. A large body of epidemiological evidences has suggested that gestational exposure to PM2.5 increases the incidence of congenital diseases in offspring, including congenital heart defects. In addition, animal model studies have revealed that gestational exposure to PM2.5 can disrupt normal heart development in offspring, although the potential molecular mechanisms have yet to be fully elucidated. The aim of the present review was to provide a brief overview of what is currently known regarding the molecular mechanisms underlying cardiac developmental toxicity in offspring induced by gestational exposure to PM2.5.

Impacts and potential mechanisms of fine particulate matter (PM2.5) on male testosterone biosynthesis disruption

Exposure to PM2.5 is the most significant air pollutant for health risk. The testosterone level in male is vulnerable to environmental toxicants. In the past, researchers focused more attention on the impacts of PM2.5 on respiratory system, cardiovascular system, and nervous system, and few researchers focused attention on the reproductive system. Recent studies have reported that PM2.5 involved in male testosterone biosynthesis disruption, which is closely associated with male reproductive health. However, the underlying mechanisms by which PM2.5 causes testosterone biosynthesis disruption are still not clear. To better understand its potential mechanisms, we based on the existing scientific publications to critically and comprehensively reviewed the role and potential mechanisms of PM2.5 that are participated in testosterone biosynthesis in male. In this review, we summarized the potential mechanisms of PM2.5 triggering the change of testosterone level in male, which involve in oxidative stress, inflammatory response, ferroptosis, pyroptosis, autophagy and mitophagy, microRNAs (miRNAs), endoplasmic reticulum (ER) stress, and N6-methyladenosine (m6A) modification. It will provide new suggestions and ideas for prevention and treatment of testosterone biosynthesis disruption caused by PM2.5 for future research.

Implication of m6A Methylation Regulators in the Immune Microenvironment of Bronchopulmonary Dysplasia

N6-methyladenosine (m6A) regulates gene expression and governs many important biological processes. However, the function of m6A in the development of bronchopulmonary dysplasia (BPD) remains poorly characterized. Thus, the purpose of this investigation was to evaluate the effects of m6A RNA methylation regulators on the development of BPD. BPD-related transcriptome data were downloaded from the GEO database. Differentially expressed m6A methylation regulators between BPD and control group were identified. Consensus clustering was conducted for the classification of BPD and association between clusters and BPD phenotypes were explored. Analysis of differentially expressed genes (DEGs) and immune-related DEGs was performed. The GSEA, GO and KEGG analyses were used to interpret the functional enrichments. The composition of immune cell subtypes in BPD subsets was predicted by CIBERSORT analysis. Compared with the control group, expression of most m6A regulators showed significant alteration, especially for IGF2BP1/2/3. BPD was classified into 2 subsets, and cluster 1 was correlated with severe BPD. Furthermore, the results of functional enrichment analyses showed a disturbed immune-related signaling pathway. Based on CIBERSORT analysis, we found that the proportion of immune cell subsets changed between cluster 1 and cluster 2. Our study revealed the implication of m6A methylation regulators in the development of BPD, which might provide a novel insight for the diagnosis and treatment of BPD.

Pulmonary Epithelium Cell Fate Determination: Chronic Obstructive Pulmonary Disease, Lung Cancer, or Both

The concurrence of chronic obstructive pulmonary disease (COPD) and lung cancer has been widely reported and extensively addressed by pulmonologists and oncologists. However, most studies have focused on shared risk factors, DNA damage pathways, immune microenvironments, inflammation, and imbalanced proteases/antiproteases. In the present review, we explore the association between COPD and lung cancer in terms of airway pluripotent cell fate determination and discuss the various cell types and signaling pathways involved in the maintenance of lung epithelium homeostasis and their involvement in the pathogenesis of co-occurring COPD and lung cancer.

The roles and regulatory mechanisms of cigarette smoke constituents in vascular remodeling

Vascular remodeling is a dynamic process involving cellular and molecular changes, including cell proliferation, migration, apoptosis and extracellular matrix (ECM) synthesis or degradation, which disrupt the homeostasis of endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). Cigarette smoke exposure (CSE) is thought to promote vascular remodeling, but the components are complex and the mechanisms are unclear. In this review, we overview the progression of major components of cigarette smoke (CS), such as nicotine and acrolein, involved in vascular remodeling in terms of ECs injury, VSMCs proliferation, migration, apoptosis, and ECM disruption. The aim was to elucidate the effects of different components of CS on different cells of the vascular system, to discover the relevance of their actions, and to provide new references for future studies.

Epigenetic regulation of diverse regulated cell death modalities in cardiovascular disease: Insights into necroptosis, pyroptosis, ferroptosis, and cuproptosis

Cell death constitutes a critical component of the pathophysiology of cardiovascular diseases. A growing array of non-apoptotic forms of regulated cell death (RCD)-such as necroptosis, ferroptosis, pyroptosis, and cuproptosis-has been identified and is intimately linked to various cardiovascular conditions. These forms of RCD are governed by genetically programmed mechanisms within the cell, with epigenetic modifications being a common and crucial regulatory method. Such modifications include DNA methylation, RNA methylation, histone methylation, histone acetylation, and non-coding RNAs. This review recaps the roles of DNA methylation, RNA methylation, histone modifications, and non-coding RNAs in cardiovascular diseases, as well as the mechanisms by which epigenetic modifications regulate key proteins involved in cell death. Furthermore, we systematically catalog the existing epigenetic pharmacological agents targeting novel forms of RCD and their mechanisms of action in cardiovascular diseases. This article aims to underscore the pivotal role of epigenetic modifications in precisely regulating specific pathways of novel RCD in cardiovascular diseases, thus offering potential new therapeutic avenues that may prove more effective and safer than traditional treatments.

Bisphenol C Induces Cardiac Developmental Defects by Disrupting m6A Homeostasis

Bisphenol A (BPA) is a commonly used plastic additive. Since BPA has been banned in maternal and infant food containers in many countries, BPA substitutes have been widely introduced to replace it. By systematically assessing the potential developmental toxicity of BPA substitutes, we observed that the 41-150 nM in vivo BPC exposure (around the reported concentration detected in infant urine: 6-186 nM) induced cardiac defects in zebrafish. Mechanistically, BPC disrupted m6A homeostasis by downregulation of the key m6A methyltransferase, Mettl3, thereby causing the m6A reader, Igf2bp2b, to fail in recognizing and stabilizing the inefficiently m6A-modified acox1 and tnnt2d mRNA. Then, downregulation of Acox1 (a regulator in cardiac fatty acid metabolism) and Tnnt2d (a component of cardiac troponin for muscle contraction) led to cardiac defects. Indeed, the dual cardiac functional axes regulated by the same m6A reader in response to BPC provided new insight into the regulatory mechanisms of epitranscriptomics and cardiac development. Collectively, our study not only presented evidence showing that the internal exposure levels of BPC in humans could lead to cardiac developmental defects but also demonstrated the underlying mechanism of BPC-mediated defects by disrupting the Mettl3-m6A-Igf2bp2b-Acox1/Tnnt2d pathways, which provided potential molecular markers associated with BPC exposure.

Fluoride exposure-induced gut microbiota alteration mediates colonic ferroptosis through N6-methyladenosine (m6A) mediated silencing of SLC7A11

Fluoride exposure is widespread worldwide and poses a significant threat to organisms, particularly to their gastrointestinal tracts. However, due to limited knowledge of the mechanism of fluoride induced intestinal injury, it has been challenging to develop an effective treatment. To address this issue, we used a series of molecular biology in vitro and in vivo experiments. NaF triggered m6A mediated ferroptosis to cause intestinal damage. Mechanistically, NaF exposure increased the m6A level of SLC7A11 mRNA, promoted YTHDF2 binding to m6A-modified SLC7A11 mRNA, drove the degradation of SLC7A11 mRNA, and led to a decrease in its protein expression, which eventually triggers ferroptosis. Moreover, NaF aggravated ferroptosis of the colon after antibiotics destroyed the composition of gut microbiota. 16 S rRNA sequencing and SPEC-OCCU plots, Zi-Pi relationships, and Spearman correlation coefficients verified that Lactobacillus murinus (ASV54, ASV58, and ASV82) plays a key role in the response to NaF-induced ferroptosis. Collectively, NaF-induced gut microbiota alteration mediates severe intestinal cell injury by inducing m6A modification-mediated ferroptosis. Our results highlight a key mechanism of the gut in response to NaF exposure and suggest a valuable theoretical basis for its prevention and treatment.

Involvement of M2 macrophages polarization in PM2.5-induced COPD by upregulating MMP12 via IL4/STAT6 pathway

Biomass-related airborne fine particulate matter (PM2.5) is an important risk factor for chronic obstructive pulmonary disease (COPD). Macrophage polarization has been reported to be involved in PM2.5-induced COPD, but the dynamic characteristics and underlying mechanism of this process remain unclear. Our study established a PM2.5-induced COPD mouse model and revealed that M2 macrophages predominantly presented after 4 and 6 months of PM2.5 exposure, during which a notable increase in MMP12 was observed. Single cell analysis of lung tissues from COPD patients and mice further revealed that M2 macrophages were the dominant macrophage subpopulation in COPD, with MMP12 being involved as a hub gene. In vitro experiments further demonstrated that PM2.5 induced M2 polarization and increased MMP12 expression. Moreover, we found that PM2.5 increased IL-4 expression, STAT6 phosphorylation and nuclear translocation. Nuclear pSTAT6 then bound to the MMP12 promoter region. Furthermore, the inhibition of STAT6 phosphorylation effectively abrogated the PM2.5-induced increase in MMP12. Using a coculture system, we observed a significantly reduced level of E-cadherin in alveolar epithelial cells cocultured with PM2.5-exposed macrophages, while the decrease in E-cadherin was reversed by the addition of an MMP12 inhibitor to the co-culture system. Taken together, these findings indicated that PM2.5 induced M2 macrophage polarization and MMP12 upregulation via the IL-4/STAT6 pathway, which resulted in alveolar epithelial barrier dysfunction and excessive extracellular matrix (ECM) degradation, and ultimately led to COPD progression. These findings may help to elucidate the role of macrophages in COPD, and suggest promising directions for potential therapeutic strategies.

YTHDC2 mediated RNA m6A modification contributes to PM2.5-induced hepatic steatosis

Exposure to fine particulate matter (PM2.5) is a significant risk factor for hepatic steatosis. The N6-methyladenosine (m6A) is implicated in metabolic disturbances triggered by exogenous environmental factors. However, the role of m6A in mediating PM2.5-induced hepatic steatosis remains unclear. Herein, male C57BL/6J mice were subjected to PM2.5 exposure throughout the entire heating season utilizing a real-ambient PM2.5 whole-body inhalation exposure system. Concurrently, HepG2 cell models exposed to PM2.5 were developed to delve the role of m6A methylation modification. Following PM2.5 exposure, significant hepatic lipid accumulation and elevated global m6A level were observed both in vitro and in vivo. The downregulation of YTHDC2, an m6A-binding protein, might contribute to this alteration. In vitro studies revealed that lipid-related genes CEPT1 and YWHAH might be targeted by m6A modification. YTHDC2 could bind to CDS region of them and increase their stability. Exposure to PM2.5 shortened mRNA lifespan and suppressed the expression of CEPT1 and YWHAH, which were reversed to baseline or higher level upon the enforced expression of YTHDC2. Consequently, our findings indicate that PM2.5 induces elevated m6A methylation modification of CEPT1 and YWHAH by downregulating YTHDC2, which in turn mediates the decrease in the mRNA stabilization and expression of these genes, ultimately resulting in hepatic steatosis.

Associations between long-term ambient PM2.5 exposure and the incidence of cardiopulmonary diseases and diabetes, attributable years lived with disability, and policy implication

Long-term exposure to ambient PM2.5 is known associated with cardiovascular and respiratory health effects. However, the heterogeneous concentrationresponse function (CRF) between PM2.5 exposure across different concentration range and cardiopulmonary disease and diabetes mellitus (DM) incidence, and their implications on attributable years lived with disability (YLD) and regulation policy has not been well-studied. In this retrospective longitudinal cohort study, disease-free participants (approximately 170,000 individuals, aged ≥ 30 years) from the MJ Health Database were followed up (2007-2017) regarding incidents of coronary heart disease (CHD), ischemic stroke, chronic obstructive pulmonary disease (COPD), lower respiratory tract infections (LRIs), and DM. We used a time-dependent nonlinear weight-transformation Cox regression model for the CRF with an address-matched 3-year mean PM2.5 exposure estimate. Town/district-specific PM2.5-attributable YLD were calculated by multiplying the disease incidence rate, population attributable fraction, disability weight, and sex-age group specific subpopulation for each disease separately. The estimated CRFs for cardiopulmonary diseases were heterogeneously with the hazard ratios (HRs) increased rapidly for CHD and ischemic stroke at PM2.5 concentration lower than 10 μg/m3, whereas the HRs for DM (LRIs) increased with PM2.5 higher than 15 (20) μg/m3. Women had higher HRs for ischemic stroke and DM but not CHD. Relative to the lowest observed PM2.5 concentration of 6 μg/m3 of the study population, the PM2.5 level with an extra risk of 0.1 % (comparable to the disease incidence) for CHD, ischemic stroke, DM, and LRIs were 8.59, 11.85, 22.09, and 24.23 μg/m3, respectively. The associated attributable YLD decreased by 51.4 % with LRIs reduced most (83.6 %), followed by DM (63.7 %) as a result of PM2.5 concentration reduction from 26.10 to 16.82 μg/m3 during 2011-2019 in Taiwan. The proportion of YLD due to CHD and ischemic stroke remained dominant (56.4 %-69.9 %). The cost-benefit analysis for the tradeoff between avoidable YLD and mitigation cost suggested an optimal PM2.5 exposure level at 12 μg/m3. CRFs for cardiopulmonary diseases, attributable YLD, and regulation level, may vary depending on the national/regional background and spatial distribution of PM2.5 concentrations, as well as demographic characteristics.

Epigenetic regulation of macrophage activation in chronic obstructive pulmonary disease

Macrophages in the innate immune system play a vital role in various lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), acute lung injury and pulmonary fibrosis. Macrophages involved in the process of immunity need to go through a process of activation, including changes in gene expression and cell metabolism. Epigenetic modifications are key factors of macrophage activation including DNA methylation, histone modification and non-coding RNA regulation. Understanding the role and mechanisms of epigenetic regulation of macrophage activation can provide insights into the function of macrophages in lung diseases and help identification of potential therapeutic targets. This review summarizes the latest progress in the epigenetic changes and regulation of macrophages in their development process and in normal physiological states, and the epigenetic regulation of macrophages in COPD as well as the influence of macrophage activation on COPD development.

piR-27222 mediates PM2.5-induced lung cancer by resisting cell PANoptosis through the WTAP/m6A axis

PM2.5 pollution has been associated with the incidence of lung cancer, but the underlying mechanism is still unclear. PIWI-interacting RNAs (piRNAs), initially identified in germline cells, have emerged as a novel class of small non-coding RNAs (26 - 32 nucleotides) with diverse functions in various diseases, including cancer. However, the role and mechanism of piRNAs in the development of PM2.5-induced lung cancer remain to be clarified. In the presented study, we used a PM2.5-induced malignant transformation cell model to analyze the change of piRNA profiles. Among the disturbed piRNAs, piR-27222 was identified as an oncogene that inhibited cell death in a m6A-dependent manner. Mechanistically, we found that piR-27222 could deubiquitinate and stabilize eIF4B by directly binding to eIF4B and reducing its interaction with PARK2. The enhanced expression of eIF4B, in turn, promoted the expression of WTAP, leading to increased m6A modification in the Casp8 transcript. Consequently, the stability of Casp8 transcripts was reduced, rendering lung cancer cells resistant to PANoptosis. Collectively, our findings reveal that PM2.5 exposure up-regulated piR-27222 expression, which could affect EIF4B/WTAP/m6A axis, thereby inhibiting PANoptosis of cells and promoting lung cancer. Our study provides new insights into understanding the epigenetic mechanisms underlining PM2.5-induced lung cancer.

Epigenetics and environmental health

Epigenetic modifications including DNA methylation, histone modifications, chromatin remodeling, and RNA modifications complicate gene regulation and heredity and profoundly impact various physiological and pathological processes. In recent years, accumulating evidence indicates that epigenetics is vulnerable to environmental changes and regulates the growth, development, and diseases of individuals by affecting chromatin activity and regulating gene expression. Environmental exposure or induced epigenetic changes can regulate the state of development and lead to developmental disorders, aging, cardiovascular disease, Alzheimer's disease, cancers, and so on. However, epigenetic modifications are reversible. The use of specific epigenetic inhibitors targeting epigenetic changes in response to environmental exposure is useful in disease therapy. Here, we provide an overview of the role of epigenetics in various diseases. Furthermore, we summarize the mechanism of epigenetic alterations induced by different environmental exposures, the influence of different environmental exposures, and the crosstalk between environmental variation epigenetics, and genes that are implicated in the body's health. However, the interaction of multiple factors and epigenetics in regulating the initiation and progression of various diseases complicates clinical treatments. We discuss some commonly used epigenetic drugs targeting epigenetic modifications and methods to prevent or relieve various diseases regulated by environmental exposure and epigenetics through diet.

Melatonin and mesenchymal stem cells co-administration alleviates chronic obstructive pulmonary disease via modulation of angiogenesis at the vascular-alveolar unit

Chronic obstructive pulmonary disease (COPD) is considered a severe disease mitigating lung physiological functions with high mortality outcomes, insufficient therapy, and pathophysiology pathways which is still not fully understood. Mesenchymal stem cells (MSCs) derived from bone marrow play an important role in improving the function of organs suffering inflammation, oxidative stress, and immune reaction. It might also play a role in regenerative medicine, but that is still questionable. Additionally, Melatonin with its known antioxidative and anti-inflammatory impact is attracting attention nowadays as a useful treatment. We hypothesized that Melatonin may augment the effect of MSCs at the level of angiogenesis in COPD. In our study, the COPD model was established using cigarette smoking and lipopolysaccharide. The COPD rats were divided into four groups: COPD group, Melatonin-treated group, MSC-treated group, and combined treated group (Melatonin-MSCs). We found that COPD was accompanied by deterioration of pulmonary function tests in response to expiratory parameter affection more than inspiratory ones. This was associated with increased Hypoxia inducible factor-1α expression and vascular endothelial growth factor level. Consequently, there was increased CD31 expression indicating increased angiogenesis with massive enlargement of airspaces and thinning of alveolar septa with decreased mean radial alveolar count, in addition to, inflammatory cell infiltration and disruption of the bronchiolar epithelial wall with loss of cilia and blood vessel wall thickening. These findings were improved significantly when Melatonin and bone marrow-derived MSCs were used as a combined treatment proving the hypothesized target that Melatonin might augment MSCs aiming at vascular changes.

Effects and mechanisms of N6-methyladenosine RNA methylation in environmental pollutant-induced carcinogenesis

Environmental pollution, including air pollution, plastic contamination, and heavy metal exposure, is a pressing global issue. This crisis contributes significantly to pollution-related diseases and is a critical risk factor for chronic health conditions, including cancer. Mounting evidence underscores the pivotal role of N6-methyladenosine (m6A) as a crucial regulatory mechanism in pathological processes and cancer progression. Governed by m6A writers, erasers, and readers, m6A orchestrates alterations in target gene expression, consequently playing a vital role in a spectrum of RNA processes, covering mRNA processing, translation, degradation, splicing, nuclear export, and folding. Thus, there is a growing need to pinpoint specific m6A-regulated targets in environmental pollutant-induced carcinogenesis, an emerging area of research in cancer prevention. This review consolidates the understanding of m6A modification in environmental pollutant-induced tumorigenesis, explicitly examining its implications in lung, skin, and bladder cancer. We also investigate the biological mechanisms that underlie carcinogenesis originating from pollution. Specific m6A methylation pathways, such as the HIF1A/METTL3/IGF2BP3/BIRC5 network, METTL3/YTHDF1-mediated m6A modification of IL 24, METTL3/YTHDF2 dynamically catalyzed m6A modification of AKT1, METTL3-mediated m6A-modified oxidative stress, METTL16-mediated m6A modification, site-specific ATG13 methylation-mediated autophagy, and the role of m6A in up-regulating ribosome biogenesis, all come into play in this intricate process. Furthermore, we discuss the direction regarding the interplay between pollutants and RNA metabolism, particularly in immune response, providing new information on RNA modifications for future exploration.

RNA modifications in pulmonary diseases

Threatening public health, pulmonary disease (PD) encompasses diverse lung injuries like chronic obstructive PD, pulmonary fibrosis, asthma, pulmonary infections due to pathogen invasion, and fatal lung cancer. The crucial involvement of RNA epigenetic modifications in PD pathogenesis is underscored by robust evidence. These modifications not only shape cell fates but also finely modulate the expression of genes linked to disease progression, suggesting their utility as biomarkers and targets for therapeutic strategies. The critical RNA modifications implicated in PDs are summarized in this review, including N6-methylation of adenosine, N1-methylation of adenosine, 5-methylcytosine, pseudouridine (5-ribosyl uracil), 7-methylguanosine, and adenosine to inosine editing, along with relevant regulatory mechanisms. By shedding light on the pathology of PDs, these summaries could spur the identification of new biomarkers and therapeutic strategies, ultimately paving the way for early PD diagnosis and treatment innovation.

Vascular Endothelial Damage in COPD: Where Are We Now, Where Will We Go?

BACKGROUND

Chronic obstructive pulmonary disease (COPD) has higher rates among the general population, so early identification and prevention is the goal. The mechanisms of COPD development have not been completely established, although it has been demonstrated that endothelial dysfunction plays an important role. However, to date, the measurement of endothelial dysfunction is still invasive or not fully established. Nailfold video capillaroscopy (NVC) is a safe, non-invasive diagnostic tool that can be used to easily evaluate the microcirculation and can show any possible endothelial dysfunctions early on. The aim of this review is to evaluate if nailfold microcirculation abnormalities can reflect altered pulmonary vasculature and can predict the risk of cardiovascular comorbidities in COPD patients.

METHODS

A systematic literature search concerning COPD was performed in electronic databases (PUBMED, UpToDate, Google Scholar, ResearchGate), supplemented with manual research. We searched in these databases for articles published until March 2024. The following search words were searched in the databases in all possible combinations: chronic obstructive pulmonary disease (COPD), endothelial damage, vascular impairment, functional evaluation, capillaroscopy, video capillaroscopy, nailfold video capillaroscopy. Only manuscripts written in English were considered for this review. Papers were included only if they were able to define a relationship between COPD and endothelium dysfunction.

RESULTS

The search selected 10 articles, and among these, only three previous reviews were available. Retinal vessel imaging, flow-mediated dilation (FMD), and skin autofluorescence (AF) are reported as the most valuable methods for assessing endothelial dysfunction in COPD patients.

CONCLUSIONS

It has been assumed that decreased nitric oxide (NO) levels leads to microvascular damage in COPD patients. This finding allows us to assume NVC's potential effectiveness in COPD patients. However, this potential link is based on assumption; further investigations are needed to confirm this hypothesis.

ALKBH5 SUMOylation-mediated FBXW7 m6A modification regulates alveolar cells senescence during 1-nitropyrene-induced pulmonary fibrosis

Our previous study revealed that 1-nitropyrene (1-NP) exposure evoked pulmonary fibrosis in mice. However, the exact mechanism remained elusive. We found that 1-NP induced telomere damage and cellular senescence in mice lungs, and two alveolar epithelial cells lines. 1-NP downregulated telomere repeat binding factor 2 (TRF2), and upregulated FBXW7. Mechanistically, 1-NP-caused TRF2 ubiquitination and proteasomal degradation depended on E3 ubiquitin ligase activity of FBXW7. Moreover, 1-NP upregulated FBXW7 m6A modification via an ALKBH5-YTHDF1-dependent manner. Further analysis suggested 1-NP promoted ALKBH5 SUMOylation and subsequent proteasomal degradation. Additionally, 1-NP evoked mitochondrial reactive oxygen species (mtROS) overproduction. Mito-TEMPO, a mitochondrial-targeted antioxidant, mitigated 1-NP-caused mtROS overproduction, ALKBH5 SUMOylation, FBXW7 m6A modification, TRF2 degradation, cellular senescence, and pulmonary fibrosis. Taken together, mtROS-initiated ALKBH5 SUMOylation and subsequent FBXW7 m6A modification is indispensable for TRF2 degradation and cellular senescence in alveolar epithelial cells during 1-NP-induced pulmonary fibrosis. Our study provides target intervention measures towards 1-NP-evoked pulmonary fibrosis.

The application of a self-designed microfluidic lung chip in the assessment of different inhalable aerosols

Microfluidic-based assessment platforms have recently attracted considerable attention and have been widely used for evaluating in vitro toxic effects. In the present study, we developed an original real-time aerosol exposure system, which focused on a self-designed microfluidic chip, in order to evaluate the toxicological effects following exposure to inhalable aerosols. The three-layer structured microfluidic chip enables real-time aerosol exposure at the gas-liquid interface. The comprehensive detection of toxic effect biomarkers based on this assessment platform encompasses transcriptomics, in situ fluorescence detection, and the identification of extracellular secretagogues. Correspondingly, the effects of selected inhalable aerosols such as cigarette smoke (CS), heated tobacco product smoke (HS), and electronic cigarette smoke (ES) on gene expression profiles, cell viability, intracellular biomarkers (reactive oxygen species and nitric oxide), apoptosis (caspase-3/7 activity), and extracellular biomarkers (IL-8, IL-1β, TNF-α, and malondialdehyde) in the BEAS-2B cells present on the chip were investigated. Following exposure to aerosols derived from CS, HS, and ES, the transcriptome analysis revealed differential expression in these cells. In addition, the overlapping DEGs from the different treatment groups were found to be primarily associated with stimuli and inflammatory responses. Correspondingly, each of the three categories of selected inhalable aerosols was confirmed to induce significant changes in biomarkers that were associated with toxic effects. These results suggest that the original real-time aerosol exposure system centered around a self-designed chip can be applied to the toxic effect evaluation of inhalable aerosol exposure.

Gelato: a new hybrid deep learning-based Informer model for multivariate air pollution prediction

The increase in air pollutants and its adverse effects on human health and the environment has raised significant concerns. This implies the necessity of predicting air pollutant levels. Numerous studies have aimed to provide new models for more accurate prediction of air pollutants such as CO2, O3, and PM2.5. Most of the models used in the literature are deep learning models with Transformers being the best for time series prediction. However, there is still a need to enhance accuracy in air pollution prediction using Transformers. Alongside the need for increased accuracy, there is a significant demand for predicting a broader spectrum of air pollutants. To encounter this challenge, this paper proposes a new hybrid deep learning-based Informer model called "Gelato" for multivariate air pollution prediction. Gelato takes a leap forward by taking several air pollutants into consideration simultaneously. Besides introducing new changes to the Informer structure as the base model, Gelato utilizes Particle Swarm Optimization for hyperparameter optimization. Moreover, XGBoost is used at the final stage to achieve minimal errors. Applying the proposed model on a dataset containing eight important air pollutants, including CO2, O3, NO, NO2, SO2, PM10, NH3, and PM2.5, the Gelato performance is assessed. Comparing the results of Gelato with other models shows Gelato's superiority over them, proving it is a high-confidence model for multivariate air pollution prediction.

METTL16 promotes osteosarcoma progression by downregulating VPS33B in an m6 A-dependent manner

N6-methyladenosine (m6 A) is one of the main epitranscriptomic modifications that accelerates the progression of malignant tumors by modifying RNA. Methyltransferase-like 16 (METTL16) is a newly identified methyltransferase that has been found to play an important oncogenic role in a few malignancies; however, its function in osteosarcoma (OS) remains unclear. In this study, METTL16 was found to be upregulated in OS tissues, and associated with poor prognosis in OS patients. Functionally, METTL16 substantially promoted OS cell proliferation, migration, and invasion in vitro and OS growth in vivo. Mechanistically, vacuolar protein sorting protein 33b (VPS33B) was identified as the downstream target of METTL16, which induced m6 A modification of VPS33B and impaired the stability of the VPS33B transcript, thereby degrading VPS33B. In addition, VPS33B was found to be downregulated in OS tissues, VPS33B knockdown markedly attenuated shMETTL16-mediated inhibition on OS progression. Finally, METTL16/VPS33B might facilitate OS progression through PI3K/AKT pathway. In summary, this study revealed an important role for the METTL16-mediated m6 A modification in OS progression, implying it as a promising target for OS treatment.

Characterization of risks and pathogenesis of respiratory diseases caused by rural atmospheric PM2.5

Forty-six percent of the world's population resides in rural areas, the majority of whom belong to vulnerable groups. They mainly use cheap solid fuels for cooking and heating, which release a large amount of PM2.5 and cause adverse effects to human health. PM2.5 exhibits urban-rural differences in its health risk to the respiratory system. However, the majority of research on this issue has focused on respiratory diseases induced by atmospheric PM2.5 in urban areas, while rural areas have been ignored for a long time, especially the pathogenesis of respiratory diseases. This is not helpful for promoting environmental equity to aid vulnerable groups under PM2.5 pollution. Thus, this study focuses on rural atmospheric PM2.5 in terms of its chemical components, toxicological effects, respiratory disease types, and pathogenesis, represented by PM2.5 from rural areas in the Sichuan Basin, China (Rural SC-PM2.5). In this study, organic carbon is the most significant component of Rural SC-PM2.5. Rural SC-PM2.5 significantly induces cytotoxicity, oxidative stress, and inflammatory response. Based on multiomics, bioinformatics, and molecular biology, Rural SC-PM2.5 inhibits ribonucleotide reductase regulatory subunit M2 (RRM2) to disrupt the cell cycle, impede DNA replication, and ultimately inhibit lung cell proliferation. Furthermore, this study supplements and supports the epidemic investigation. Through an analysis of the transcriptome and human disease database, it is found that Rural SC-PM2.5 may mainly involve pulmonary hypertension, sarcoidosis, and interstitial lung diseases; in particular, congenital diseases may be ignored by epidemiological surveys in rural areas, including tracheoesophageal fistula, submucous cleft of the hard palate, and congenital hypoplasia of the lung. This study contributes to a greater scientific understanding of the health risks posed by rural PM2.5, elucidates the pathogenesis of respiratory diseases, clarifies the types of respiratory diseases, and promotes environmental equity.

Multivariable Air-Quality Prediction and Modelling via Hybrid Machine Learning: A Case Study for Craiova, Romania

Inadequate air quality has adverse impacts on human well-being and contributes to the progression of climate change, leading to fluctuations in temperature. Therefore, gaining a localized comprehension of the interplay between climate variations and air pollution holds great significance in alleviating the health repercussions of air pollution. This study uses a holistic approach to make air quality predictions and multivariate modelling. It investigates the associations between meteorological factors, encompassing temperature, relative humidity, air pressure, and three particulate matter concentrations (PM10, PM2.5, and PM1), and the correlation between PM concentrations and noise levels, volatile organic compounds, and carbon dioxide emissions. Five hybrid machine learning models were employed to predict PM concentrations and then the Air Quality Index (AQI). Twelve PM sensors evenly distributed in Craiova City, Romania, provided the dataset for five months (22 September 2021-17 February 2022). The sensors transmitted data each minute. The prediction accuracy of the models was evaluated and the results revealed that, in general, the coefficient of determination (R2) values exceeded 0.96 (interval of confidence is 0.95) and, in most instances, approached 0.99. Relative humidity emerged as the least influential variable on PM concentrations, while the most accurate predictions were achieved by combining pressure with temperature. PM10 (less than 10 µm in diameter) concentrations exhibited a notable correlation with PM2.5 (less than 2.5 µm in diameter) concentrations and a moderate correlation with PM1 (less than 1 µm in diameter). Nevertheless, other findings indicated that PM concentrations were not strongly related to NOISE, CO2, and VOC, and these last variables should be combined with another meteorological variable to enhance the prediction accuracy. Ultimately, this study established novel relationships for predicting PM concentrations and AQI based on the most effective combinations of predictor variables identified.

Exploring the importance of m5c in the diagnosis and subtype classification of COPD using the GEO database

BACKGROUND

5-Methylcytosine (m5C) is an mRNA modifier that is associated with the occurrence and development of viral infection, pulmonary fibrosis, lung cancer, and other diseases. However, the role of m5C regulators in chronic obstructive pulmonary disease (COPD) remains unknown.

METHODS

In this study, by analysing the GSE42057 dataset, the differential expression of m5c regulators in the COPD group and control group was obtained, and a correlation analysis was conducted. The random forest model and support vector machine model were used to predict the occurrence of COPD. A nomogram model was also constructed to predict the prevalence of COPD. The COPD patients were divided into subtypes by consistent cluster analysis based on m5c methylation regulators. Immune cell infiltration was performed on the m5c methylation subtypes. Differentially expressed genes (DEGs) between m5c methylation subtypes were screened, and the DEGs were analysed by Gene Ontology (GO) Kyoto Encyclopedia of Genes and Genomes (KEGG). Finally, we verified the expression of several m5C regulators and related pathways using a COPD cell model.

RESULTS

Seven m5c methylation regulators were differentially expressed. The random forest model based on the above genes was the most accurate for predicting the occurrence of COPD. A nomogram model based on the above genes could also accurately predict the prevalence of COPD, and the implementation of these models could benefit COPD patients. The consistent cluster analysis divided the COPD patients into two subtypes (Cluster A and Cluster B). The main component analysis algorithm determined the m5c methylation subtypes and found that patients in Cluster A had a higher m5c score than those in Cluster B. GO analysis of the DEGs between the m5c methylation COPD patient subtypes revealed that DEGS were mainly enriched in leukocyte-mediated immunity and regulation of T-cell activation. KEGG analysis revealed that DEGS were mainly enriched in Th1 and Th2 cell differentiation, neutrophil extracellular trap formation, and the NF-κB signalling pathway. Immunocyte correlation analysis revealed that Cluster B was associated with neutrophil- and macrophage-mediated immunity, while Cluster A was associated with CD4 + T-cell- and CD8 + T-cell-mediated immunity. Cell experiments have also verified some of the above research results.

CONCLUSION

The diagnosis and subtype classification of COPD patients based on m5c regulators may provide a new strategy for the diagnosis and treatment of COPD.

The N6-methyladenosine modification in pathologic angiogenesis

The vascular system is a vital circulatory network in the human body that plays a critical role in almost all physiological processes. The production of blood vessels in the body is a significant area of interest for researchers seeking to improve their understanding of vascular function and maintain normal vascular operation. However, an excessive or insufficient vascular regeneration process may lead to the development of various ailments such as cancer, eye diseases, and ischemic diseases. Recent preclinical and clinical studies have revealed new molecular targets and principles that may enhance the therapeutic effect of anti-angiogenic strategies. A thorough comprehension of the mechanism responsible for the abnormal vascular growth in disease processes can enable researchers to better target and effectively suppress or treat the disease. N6-methyladenosine (m6A), a common RNA methylation modification method, has emerged as a crucial regulator of various diseases by modulating vascular development. In this review, we will cover how m6A regulates various vascular-related diseases, such as cancer, ocular diseases, neurological diseases, ischemic diseases, emphasizing the mechanism of m6A methylation regulators on angiogenesis during pathological process.

M6A plays a potential role in carotid atherosclerosis by modulating immune cell modification and regulating aging-related genes

RNA N6-methyladenosine (m6A) regulators play essential roles in diverse biological processes, including immune responses. Mounting evidence suggests that their dysregulation is intricately linked to numerous diseases. However, the role of m6A-associated genes in carotid atherosclerosis and their relationship with aging and immune cells remain unclear. Analyze the expression profiles of m6A-related genes in carotid atherosclerosis-related datasets. Based on the expression patterns of m6A-related genes, perform consistent clustering analysis of carotid atherosclerosis samples and investigate associated immune cell infiltration patterns and aging characteristics. Develop an m6A prediction model specific to carotid atherosclerosis and analyze the relationships between immune cells infiltration and aging features. The m6A methylation modification level exhibited a substantial decrease in early-stage carotid atherosclerosis samples compared to late-stage carotid atherosclerosis samples. Subsequently, two distinct m6A subtypes were defined through consensus clustering analysis, with the lower m6A modification level group showing associations with heightened immune cell infiltration and increased expression of aging-related genes. A model composed of five m6A-related genes was formulated, and the results indicated that this model possesses effective predictive and therapeutic capabilities for carotid atherosclerosis. Furthermore, the downregulation of YTHDC1 expression resulted in elevated expression of inflammatory factors and a decrease in the expression of the aging-related gene RGN. Single-cell data analysis suggests that the reduced expression of YTHDC1 may decrease the degradation of inflammation-related factors in macrophages, leading to a highly inflammatory state in the carotid artery wall. Furthermore, the sustained release of inflammatory factors may increase the expression of the aging-related gene RGN in vascular smooth muscle cells, further exacerbating the progression of atherosclerosis. A reduced level of m6A methylation modification could enhance inflammation and expedite cellular aging, thereby contributing to the development of carotid atherosclerosis.

The occurrence, sources, and health risks of substituted polycyclic aromatic hydrocarbons (SPAHs) cannot be ignored

Similar to parent polycyclic aromatic hydrocarbons (PPAHs), substituted PAHs (SPAHs) are prevalent in the environment and harmful to humans. However, they have not received much attention. This study investigated the occurrence, distribution, and sources of 10 PPAHs and 15 SPAHs in soil, water, and indoor and outdoor PM2.5 and dust in high-exposure areas (EAH) near industrial parks and low-exposure areas (EAL) far from industrial parks. PAH pollution in all media was more severe in the EAH than in the EAL. All SPAHs were detected in this study, with alkylated and oxygenated PAHs being predominant. Additionally, 3-OH-BaP and 1-OH-Pyr were detected in all dust samples in this study, and 6-N-Chr, a compound with carcinogenicity 10 times higher than that of BaP, was detected at high levels in all tap water samples. According to the indoor-outdoor ratio, PAHs in indoor PM2.5 in the EAH mainly originated from indoor pollution sources; however, those in the EAL were simultaneously affected by indoor-outdoor air exchange and indoor sources. Most target PAHs tended to deposit from air to dust, and this tendency was significantly negatively associated with the octanol-air partitioning coefficient of PAHs. SPAHs in the environment are primarily derived from the petroleum industry and the mixed combustion of gasoline, biomass, and coal. The toxicity equivalence factors of SPAHs were predicted using QSAR models to assess their lifetime carcinogenic risk (ILCR). The ILCRtotal from PAHs for adults in the EAH was >10-4. Though the levels of 6-N-Chr and 1-Me-Pyr in the environment were markedly lower than those of PPAHs, their ILCRs from PM2.5 inhalation and dermal contact with water exceeded 10-6. This study is significant for recognizing and controlling the health risks associated with SPAHs in humans.

METTL16 in human diseases: What should we do next?

METTL16 is a class-I methyltransferase that is responsible for depositing a vertebrate-conserved S-adenosylmethionine site. Since 2017, there has been a growing body of research focused on METTL16, particularly in the field of structural studies. However, the role of METTL16 in cell biogenesis and human diseases has not been extensively studied, with limited understanding of its function in disease pathology. Recent studies have highlighted the complex and sometimes contradictory role that METTL16 plays in various diseases. In this work, we aim to provide a comprehensive summary of the current research on METTL16 in human diseases.

Effect of acute PM2.5 exposure on PTGS2 and RNA m6A modification

Particulate matter 2.5 (PM2.5) is a prevalent risk factor in many diseases, but its molecular mechanism remains ambiguous and may be diverse. RNA m6A is an important epigenetic modification that regulates gene expression at the post-transcriptional level. Some previous animal exposure studies found that PM2.5 exposure up-regulated m6A RNA methylation in the lung, but there is no research on m6A RNA methylation in humans from PM2.5 exposure now. Here, in the present experiment, we performed a panel study of 65 students at the Chinese research academy of environmental sciences (CRAES) with 3 rounds of follow-up visits from August 2021 to January 2022. We examined m6A RNA modification profiles of peripheral blood mononuclear cells (PBMCs) from subjects after low and high concentrations of ambient PM2.5 exposure. We applied a linear mixed-effect (LME) model to investigate the association between PM2.5 exposure and global m6A RNA methylation and PTGS2 level in peripheral blood. We found that increased levels of global m6A RNA methylation and PTGS2 level were associated with higher PM2.5 exposure. Among the methylated mRNAs, PTGS2 was hyper-methylated after high concentrations of PM2.5 exposure, which coincided with the increased expression of PTGS2 mRNA. In the present study, we determined that PM2.5 exposure promoted RNA m6A modification, and PTGS2 in peripheral blood could serve as a novel regulatory factor of inflammation induced by PM2.5 exposure. Furthermore, RNA m6A modification may contribute to the altered expression of PTGS2 induced by PM2.5 exposure. Our finding provided a new perspective for the prevention and treatment of PM2.5 exposure-induced adverse health effects.

The Activation of M1 Macrophages is Associated with the JNK-m6A-p38 Axis in Chronic Obstructive Pulmonary Disease

Background

Excessive activation of M1 macrophages affects the chronic inflammatory response of the airways and leads to the development of chronic obstructive pulmonary disease (COPD). Therefore, it needs to be closely monitored and investigated. MAPK signaling pathway is involved in the activation of M1 macrophages, and N6-methyladenosine (m6A) is involved in the pathogenesis of COPD. However, it is unknown whether activation of the MAPK signaling pathway is mediated by m6A in M1 macrophages in COPD.

Methods

The GEO data were analyzed using bioinformatics techniques to assess the differences between COPD and healthy individuals in the levels of M1 macrophages, their secreted cytokines, and m6A regulators. The MAPK signaling pathway was significantly enriched in the list of differentially regulated genes between COPD and healthy individuals. We further analyzed the correlation between M1 macrophages, m6A, and the MAPK signaling pathway. Next, blood samples from COPD and healthy individuals were collected and analyzed by using flow cytometry, ELISA, and RT-PCR. Western blotting was performed using CSE-induced THP-1 cells. COPD and healthy mice were used for Me-RIP sequencing and flow cytometry experiments. Validation of the results of the above bioinformatics analysis by molecular biology experiments and sequencing techniques.

Results

We found that GEO data and blood specimens from COPD patients showed increased M1 macrophages, higher levels of IL-6 and TNF-α, and higher mRNA expression of key mediators of the MAPK signaling pathway (p38, ERK, and JNK). Western blotting showed increased expression of p38, ERK, and JNK in the CSE group. In contrast, the expression of m6A regulators was low. Also, M1 macrophages in COPD mice were hyperactivated and had reduced m6A modifications of p38, ERK, and JNK compared with control.

Conclusion

m6A may be involved in M1 macrophage hyperactivation by regulating the MAPK signaling pathway, thereby influencing the development of COPD.

Long-term PM2.5 exposure disrupts corneal epithelial homeostasis by impairing limbal stem/progenitor cells in humans and rat models

BACKGROUND

Limbal stem/progenitor cells (LSPCs) play a crucial role in maintaining corneal health by regulating epithelial homeostasis. Although PM2.5 is associated with the occurrence of several corneal diseases, its effects on LSPCs are not clearly understood.

METHODS

In this study, we explored the correlation between PM2.5 exposure and human limbal epithelial thickness measured by Fourier-domain Optical Coherence Tomography in the ophthalmologic clinic. Long- and short-term PM2.5 exposed-rat models were established to investigate the changes in LSPCs and the associated mechanisms.

RESULTS

We found that people living in regions with higher PM2.5 concentrations had thinner limbal epithelium, indicating the loss of LSPCs. In rat models, long-term PM2.5 exposure impairs LSPCs renewal and differentiation, manifesting as corneal epithelial defects and thinner epithelium in the cornea and limbus. However, LSPCs were activated in short-term PM2.5-exposed rat models. RNA sequencing implied that the circadian rhythm in LSPCs was perturbed during PM2.5 exposure. The mRNA level of circadian genes including Per1, Per2, Per3, and Rev-erbα was upregulated in both short- and long-term models, suggesting circadian rhythm was involved in the activation and dysregulation of LSPCs at different stages. PM2.5 also disturbed the limbal microenvironment as evidenced by changes in corneal subbasal nerve fiber density, vascular density and permeability, and immune cell infiltration, which further resulted in the circadian mismatches and dysfunction of LSPCs.

CONCLUSION

This study systematically demonstrates that PM2.5 impairs LSPCs and their microenvironment. Moreover, we show that circadian misalignment of LSPCs may be a new mechanism by which PM2.5 induces corneal diseases. Therapeutic options that target circadian rhythm may be viable options for improving LSPC functions and alleviating various PM2.5-associated corneal diseases.

PM2.5 leads to adverse pregnancy outcomes by inducing trophoblast oxidative stress and mitochondrial apoptosis via KLF9/CYP1A1 transcriptional axis

Epidemiological studies have demonstrated that fine particulate matter (PM2.5) is associated with adverse obstetric and postnatal metabolic health outcomes, but the mechanism remains unclear. This study aimed to investigate the toxicological pathways by which PM2.5 damaged placental trophoblasts in vivo and in vitro. We confirmed that PM2.5 induced adverse gestational outcomes such as increased fetal mortality rates, decreased fetal numbers and weight, damaged placental structure, and increased apoptosis of trophoblasts. Additionally, PM2.5 induced dysfunction of the trophoblast cell line HTR8/SVneo, including in its proliferation, apoptosis, invasion, migration and angiogenesis. Moreover, we comprehensively analyzed the transcriptional landscape of HTR8/SVneo cells exposed to PM2.5 through RNA-Seq and observed that PM2.5 triggered overexpression of pathways involved in oxidative stress and mitochondrial apoptosis to damage HTR8/SVneo cell biological functions through CYP1A1. Mechanistically, PM2.5 stimulated KLF9, a transcription factor identified as binding to CYP1A1 promoter region, which further modulated the CYP1A1-driven downstream phenotypes. Together, this study demonstrated that the KLF9/CYP1A1 axis played a crucial role in the toxic progression of PM2.5 induced adverse pregnancy outcomes, suggesting adverse effects of environmental pollution on pregnant females and putative targeted therapeutic strategies.

Emerging Roles for DNA 6mA and RNA m6A Methylation in Mammalian Genome

Epigenetic methylation has been shown to play an important role in transcriptional regulation and disease pathogenesis. Recent advancements in detection techniques have identified DNA N6-methyldeoxyadenosine (6mA) and RNA N6-methyladenosine (m6A) as methylation modifications at the sixth position of adenine in DNA and RNA, respectively. While the distributions and functions of 6mA and m6A have been extensively studied in prokaryotes, their roles in the mammalian brain, where they are enriched, are still not fully understood. In this review, we provide a comprehensive summary of the current research progress on 6mA and m6A, as well as their associated writers, erasers, and readers at both DNA and RNA levels. Specifically, we focus on the potential roles of 6mA and m6A in the fundamental biological pathways of the mammalian genome and highlight the significant regulatory functions of 6mA in neurodegenerative diseases.

Epitranscriptional Regulation: From the Perspectives of Cardiovascular Bioengineering

The central dogma of gene expression involves DNA transcription to RNA and RNA translation into protein. As key intermediaries and modifiers, RNAs undergo various forms of modifications such as methylation, pseudouridylation, deamination, and hydroxylation. These modifications, termed epitranscriptional regulations, lead to functional changes in RNAs. Recent studies have demonstrated crucial roles for RNA modifications in gene translation, DNA damage response, and cell fate regulation. Epitranscriptional modifications play an essential role in development, mechanosensing, atherogenesis, and regeneration in the cardiovascular (CV) system, and their elucidation is critically important to understanding the molecular mechanisms underlying CV physiology and pathophysiology. This review aims at providing biomedical engineers with an overview of the epitranscriptome landscape, related key concepts, recent findings in epitranscriptional regulations, and tools for epitranscriptome analysis. The potential applications of this important field in biomedical engineering research are discussed.

AHR-mediated m6A RNA methylation contributes to PM2.5-induced cardiac malformations in zebrafish larvae

A growing body of evidence indicates that ambient fine particle matter (PM_2.5) exposure inhibits heart development, but the underlying mechanisms remain elusive. We hypothesized that m⁶A RNA methylation plays an important role in the cardiac developmental toxicity of PM_2.5. In this study, we demonstrated that extractable organic matter (EOM) from PM2.5 significantly decreased global m⁶A RNA methylation levels in the heart of zebrafish larvae, which were restored by the methyl donor, betaine. Betaine also attenuated EOM-induced ROS overgeneration, mitochondrial damage, apoptosis and heart defects. Furthermore, we found that the aryl hydrocarbon receptor (AHR), which was activated by EOM_, directly repressed the transcription of methyltransferases mettl14 and mettl3. EOM also induced genome-wide m⁶A RNA methylation changes, which led us to focus more on the aberrant m⁶A methylation changes that were subsequently alleviated by the AHR inhibitor, CH223191. In addition, we found that the expression levels of traf4a and bbc3, two apoptosis related genes, were upregulated by EOM but restored to control levels by the forced expression of mettl14. Moreover, knockdown of either traf4a or bbc3 attenuated EOM-induced ROS overproduction and apoptosis. In conclusion, our results indicate that PM_2.5 induces m⁶A RNA methylation changes via AHR-mediated mettl14 downregulation, which upregulates traf4a and bbc3, leading to apoptosis and cardiac malformations.

N6-methyladenosine-methylomic landscape of lung tissues of mice with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), a common respiratory disease, can be divided into stable phase and acute exacerbation phase (AECOPD) and is characterized by inflammation and hyper-immunity. Methylation of N6-methyladenosine (m6A) is an epigenetic modification that regulates the expression and functions of genes by influencing post-transcriptional RNA modifications. Its influence on the immune regulation mechanism has attracted great attention. Herein, we present the m6Amethylomic landscape and observe how the methylation of m6A participates in the pathological process of COPD. The m6A modification of 430 genes increased and that of 3995 genes decreased in the lung tissues of mice with stable COPD. The lung tissues of mice with AECOPD exhibited 740 genes with hypermethylated m6A peak and 1373 genes with low m6A peak. These differentially methylated genes participated in signaling pathways related to immune functions. To further clarify the expression levels of differentially methylated genes, RNA immunoprecipitation sequencing (MeRIP-seq) and RNA-sequencing data were jointly analyzed. In the stable COPD group, 119 hypermethylated mRNAs (82 upregulated and 37 downregulated mRNAs) and 867 hypomethylated mRNAs (419 upregulated and 448 downregulated mRNAs) were differentially expressed. In the AECOPD group, 87 hypermethylated mRNAs (71 upregulated and 16 downregulated mRNAs) and 358 hypomethylated mRNAs (115 upregulated and 243 downregulated mRNAs) showed differential expression. Many mRNAs were related to immune function and inflammation. Together, this study provides important evidence on the role of RNA methylation of m6A in COPD.

Interaction between N6-methyladenosine (m6A) modification and environmental chemical-induced diseases in various organ systems

A wide variety of chemicals are ubiquitous in the environment and thus exposure to these environmental chemicals poses a serious threat to public health. Particularly, environmental factors such as air pollution, heavy metals, and endocrine-disrupting chemicals (EDCs) can lead to diseases in various organ systems. Recent research in environmental epigenetics has demonstrated that N6-methyladenosine (m6A) modification is a key mechanism of environment-related diseases. m6A modification is the most abundant chemical modification in mRNAs, which can specifically regulate gene expression by affecting RNA translation, stability, processing, and nuclear export. In this review, we discussed how environmental chemicals affected m6A modification and mediated environment-related disease occurrence by classifying the diseases of various systems. Here, we conclude that environmental chemicals alter the levels of m6A and its modulators, which then participate in the occurrence of diseases in various systems by regulating gene expression and downstream signaling pathways such as METTL3/m6A ZBTB4/YTHDF2/EZH2, Foxo3a/FTO/m6A ephrin-B2/YTHDF2, and HIF1A/METTL3/m6A BIRC5/IGF2BP3/VEGFA. Considering the significant role of m6A and its modulators in response to environmental chemicals, they are expected to be used as biomarkers of environment-related diseases. Additionally, targeting m6A modulators using small molecule inhibitors and activators is expected to be a new method for the treatment of environment-related diseases. This review systematically and comprehensively clarifies the important role of m6A in diseases caused by environmental chemicals, thus establishing a scientific basis for the treatment of diseases in various organ systems.

Drivers and Decoupling Effects of PM2.5 Emissions in China: An Application of the Generalized Divisia Index

Although economic growth brings abundant material wealth, it is also associated with serious PM_2.5 pollution. Decoupling PM_2.5 emissions from economic development is important for China's long-term sustainable development. In this paper, the generalized Divisia index method (GDIM) is extended by introducing innovation indicators to investigate the main drivers of PM_2.5 pollution in China and its four subregions from 2008 to 2017. Afterwards, a GDIM-based decoupling index is developed to examine the decoupling states between PM_2.5 emissions and economic growth and to identify the main factors leading to decoupling. The obtained results show that: (1) Innovation input scale and GDP are the main drivers for increases in PM_2.5 emissions, while innovation input PM_2.5 intensity, emission intensity, and emission coefficient are the main reasons for reductions in PM_2.5 pollution. (2) China and its four subregions show general upward trends in the decoupling index, and their decoupling states turn from weak decoupling to strong decoupling. (3) Innovation input PM_2.5 intensity, emission intensity, and emission coefficient contribute largely to the decoupling of PM_2.5 emissions. Overall, this paper provides valuable information for mitigating haze pollution.

Stability of SARS-CoV-2 in cold-chain transportation environments and the efficacy of disinfection measures

Background

Low temperature is conducive to the survival of COVID-19. Some studies suggest that cold-chain environment may prolong the survival of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and increase the risk of transmission. However, the effect of cold-chain environmental factors and packaging materials on SARS-CoV-2 stability remains unclear.

Methods

This study aimed to reveal cold-chain environmental factors that preserve the stability of SARS-CoV-2 and further explore effective disinfection measures for SARS-CoV-2 in the cold-chain environment. The decay rate of SARS-CoV-2 pseudovirus in the cold-chain environment, on various types of packaging material surfaces, i.e., polyethylene plastic, stainless steel, Teflon and cardboard, and in frozen seawater was investigated. The influence of visible light (wavelength 450 nm-780 nm) and airflow on the stability of SARS-CoV-2 pseudovirus at -18°C was subsequently assessed.

Results

Experimental data show that SARS-CoV-2 pseudovirus decayed more rapidly on porous cardboard surfaces than on nonporous surfaces, including polyethylene (PE) plastic, stainless steel, and Teflon. Compared with that at 25°C, the decay rate of SARS-CoV-2 pseudovirus was significantly lower at low temperatures. Seawater preserved viral stability both at -18°C and with repeated freeze-thaw cycles compared with that in deionized water. Visible light from light-emitting diode (LED) illumination and airflow at -18°C reduced SARS-CoV-2 pseudovirus stability.

Conclusion

Our studies indicate that temperature and seawater in the cold chain are risk factors for SARS-CoV-2 transmission, and LED visible light irradiation and increased airflow may be used as disinfection measures for SARS-CoV-2 in the cold-chain environment.

RNA Epigenetics in Chronic Lung Diseases

Chronic lung diseases are highly prevalent worldwide and cause significant mortality. Lung cancer is the end stage of many chronic lung diseases. RNA epigenetics can dynamically modulate gene expression and decide cell fate. Recently, studies have confirmed that RNA epigenetics plays a crucial role in the developing of chronic lung diseases. Further exploration of the underlying mechanisms of RNA epigenetics in chronic lung diseases, including lung cancer, may lead to a better understanding of the diseases and promote the development of new biomarkers and therapeutic strategies. This article reviews basic information on RNA modifications, including N⁶ methylation of adenosine (m⁶A), N¹ methylation of adenosine (m¹A), N⁷-methylguanosine (m⁷G), 5-methylcytosine (m⁵C), 2'O-methylation (2'-O-Me or Nm), pseudouridine (5-ribosyl uracil or Ψ), and adenosine to inosine RNA editing (A-to-I editing). We then show how they relate to different types of lung disease. This paper hopes to summarize the mechanisms of RNA modification in chronic lung disease and finds a new way to develop early diagnosis and treatment of chronic lung disease.

Dependence Analysis of PM2.5 Concentrations in 295 Chinese Cities in the Winter of 2019–2020

Considering the current severe atmospheric pollution problems in China, a comprehensive understanding of the distribution and spatial variability of PM2.5 is critically important for controlling pollution and improving the future atmospheric environment. This study first explored the distribution of PM2.5 concentrations in China, and then developed a methodology of “dependence analysis” to investigate the relationship of PM2.5 in different cities in China. The data of daily PM2.5 concentrations were collected from the environmental monitoring stations in 295 cities in China. This study also developed a set of procedures to evaluate the spatial dependence of PM2.5 among the 295 Chinese cities. The results showed that there was a total of 154 city pairs with dependence type “11”, under a significance level of 0.5%. Dependence type “11” mainly occurred between nearby cities, and the distance between 89.0% of the dependent city pairs was less than 200 km. Furthermore, the dependent pairs mainly clustered in the North China Plain, the Northeast Plain, the Middle and Lower Yangtze Plain and the Fen-Wei Plain. The geographic conditions of the Plain areas were more conducive to the spread of PM2.5 contaminants, while the mountain topography was unfavorable for the formation of PM2.5 dependencies. The dependent city couples with distances greater than 200 km were all located within the Plain areas. The high concentration of PM2.5 did not necessarily lead to PM2.5 dependences between city pairs. The methodology and models developed in this study will help explain the concentration distributions and spatial dependence of the main atmospheric pollutants in China, providing guidance for the prevention of large-scale air pollution, and the improvement of the future atmospheric environment.