Fine particulate matter 2.5 exerted its toxicological effect by regulating a new layer, long non-coding RNA

PM10 dysregulates epithelial barrier function in human corneal epithelial cells that is restored by antioxidant SKQ1

Exposure to airborne particulate <10 μm (PM10) adversely affects the ocular surface. This study tested PM10 on epithelial barrier integrity in immortalized human corneal epithelial cells (HCE-2) and mouse cornea, and whether antioxidant SKQ1 is restorative. HCE-2 were exposed to 100 μg/ml PM10 ± SKQ1 for 24 h. An Electric Cell-Substrate Impedance Sensing (ECIS) system monitored the impact of PM10. RT-PCR, western blotting and immunofluorescence measured levels of barrier and associated proteins, stanniocalcin 2 (STC2), and a kit measured total calcium. In vivo, female C57BL/6 mice were exposed to either control air or PM10 (±SKQ1) in a whole-body exposure chamber, and barrier associated proteins tested. Tight junction and mucins proteins in the cornea were tested. In HCE-2, PM0 vs control significantly reduced mRNA and protein levels of tight junction and adherence proteins, and mucins. ECIS data demonstrated that PM10 vs control cells exhibited a significant decrease in epithelial barrier strength at 4000 Hz indicated by reduced impedance and resistance. PM10 also upregulated STC2 protein and total calcium levels. In vivo, PM10 vs control reduced zonula occludens 1 and mucins. SKQ1 pre-treatment reversed PM10 effects both in vitro and in vivo. In conclusion, PM10 exposure reduced tight junction and mucin proteins, and compromised the seal between cells in the corneal epithelium leading to decreased epithelial barrier strength. This effect was reversed by SKQ1. Since the corneal epithelium forms the first line of defense against air pollutants, including PM10, preserving its integrity using antioxidants such as SKQ1 is crucial in reducing the occurrence of ocular surface disorders.

Exosomal miR-196b secreted from bronchial epithelial cells chronically exposed to low-dose PM2.5 promotes invasiveness of adjacent and lung cancer cells

Fine particulate matter (PM2.5) is a risk factor for pulmonary diseases and lung cancer, and inhaled PM2.5 is mainly deposited in the bronchial epithelium. In this study, we investigated the effect of long-term exposure to low-dose PM2.5 on BEAS-2B cells derived from the normal bronchial epithelium. BEAS-2B cells chronically exposed to a concentration of 5 µg/ml PM2.5 for 30 passages displayed the phenotype promoting epithelial-mesenchymal transition (EMT) and cell invasion. Cellular internalization of exosomes (designated PM2.5 Exo) extracted from BEAS-2B cells chronically exposed to low-dose PM2.5 promoted cell invasion in vitro and metastatic potential in vivo. Hence, to identify the key players driving phenotypic alterations, we analyzed microRNA (miRNA) expression profiles in PM2.5 Exo. Five miRNAs with altered expression were selected: miRNA-196b-5p, miR-135a-2-5p, miR-3117-3p, miR-218-5p, and miR-497-5p. miR-196b-5p was the most upregulated in both BEAS-2B cells and isolated exosomes after PM2.5 exposure. In a functional validation study, genetically modified exosomes overexpressing a miR-196b-5p mimic induced an enhanced invasive phenotype in BEAS-2B cells. Conversely, miR-196b-5p inhibition diminished the PM2.5-enhanced EMT and cell invasion. These findings indicate that exosomal miR-196b-5p may be a candidate biomarker for predicting the malignant behavior of the bronchial epithelium and a therapeutic target for inhibiting PM2.5-triggered pathogenesis.

Beyond the genome: MALAT1's role in advancing urologic cancer care

Urologic cancers (UCs), which include bladder, kidney, and prostate tumors, account for almost a quarter of all malignancies. Long non-coding RNAs (lncRNAs) are tissue-specific RNAs that influence cell growth, death, and division. LncRNAs are dysregulated in UCs, and their abnormal expression may allow them to be used in cancer detection, outlook, and therapy. With the identification of several novel lncRNAs and significant exploration of their functions in various illnesses, particularly cancer, the study of lncRNAs has evolved into a new obsession. MALAT1 is a flexible tumor regulator implicated in an array of biological activities and disorders, resulting in an important research issue. MALAT1 appears as a hotspot, having been linked to the dysregulation of cell communication, and is intimately linked to cancer genesis, advancement, and response to treatment. MALAT1 additionally operates as a competitive endogenous RNA, binding to microRNAs and resuming downstream mRNA transcription and operation. This regulatory system influences cell growth, apoptosis, motility, penetration, and cell cycle pausing. MALAT1's evaluation and prognosis significance are highlighted, with a thorough review of its manifestation levels in several UC situations and its association with clinicopathological markers. The investigation highlights MALAT1's adaptability as a possible treatment target, providing fresh ways for therapy in UCs as we integrate existing information The article not only gathers current knowledge on MALAT1's activities but also lays the groundwork for revolutionary advances in the treatment of UCs.

Dynamic relationship between the aryl hydrocarbon receptor and long noncoding RNA balances cellular and toxicological responses

The aryl hydrocarbon receptor (AhR) is a cytosolic transcription factor activated by endogenous ligands and xenobiotic chemicals. Once the AhR is activated, it translocates to the nucleus, dimerizes with the AhR nuclear translator (ARNT) and binds to xenobiotic response elements (XRE) to promote gene transcription, notably the cytochrome P450 CYP1A1. The AhR not only mediates the toxic effects of environmental chemicals, but also has numerous putative physiological functions. This dichotomy in AhR biology may be related to reciprocal regulation of long non-coding RNA (lncRNA). lncRNA are defined as transcripts more than 200 nucleotides in length that do not encode a protein but are implicated in many physiological processes such as cell differentiation, cell proliferation, and apoptosis. lncRNA are also linked to disease pathogenesis, particularly the development of cancer. Recent studies have revealed that AhR activation by environmental chemicals affects the expression and function of lncRNA. In this article, we provide an overview of AhR signaling pathways activated by diverse ligands and highlight key differences in the putative biological versus toxicological response of AhR activation. We also detail the functions of lncRNA and provide current data on their regulation by the AhR. Finally, we outline how overlap in function between AhR and lncRNA may be one way in which AhR can be both a regulator of endogenous functions but also a mediator of toxicological responses to environmental chemicals. Overall, more research is still needed to fully understand the dynamic interplay between the AhR and lncRNA.

Fine particulate matter exposure disturbs autophagy, redox balance and mitochondrial homeostasis via JNK activation to inhibit proliferation and promote EMT in human alveolar epithelial A549 cells

Epidemiologic studies have demonstrated a direct correlation between fine particulate matter (FPM) exposure and the high risk of respiratory diseases. FPM can penetrate deep into the lung and deposit in the alveoli with breath, where it directly interacts with alveolar epithelial cell (APC). However, we know little about the effects nor mechanisms of FPM on APC. Here, using human APC A549 cells, we found that FPM resulted in blockade of autophagic flux, redox imbalance and oxidative stress, mitochondrial fragmentation, increased mitophagy and impaired mitochondrial respiration. Further we showed that activation of JNK signaling (c-Jun N-terminal kinase) and excessive ROS (reactive oxygen species) release contribute to these adverse effects, with the former being upstream of the latter. More importantly, we found that scavenging ROS or inhibiting JNK activation could restore those effects as well as ameliorate FPM-induced inhibition of cell proliferation, and epithelial-mesenchymal transformation (EMT) in A549 cells. Taken together, our findings indicate that FPM leads to toxicity in alveolar type II cells via JNK activation, and JNK-targeting or antioxidant strategies might be beneficial for prevention or treatment of FPM-related pulmonary diseases.

Identification and characterization of circular RNA in the model of autism spectrum disorder from PM2.5 exposure

PM_2.5 induces a series of effects on neurological disorders, including autism spectrum disorder (ASD), however, the mechanism is not completely clear yet. Circular RNAs (circRNAs) are a class of closed-loop structures that can be stably expressed in vivo. In our experiments, rats exposed to PM_2.5 exhibited autism-like phenotypes, such as anxiety, and memory loss. To explore the etiology, we performed transcriptome sequencing and found significant differences in the expression of circRNA. A total of 7770 circRNAs were identified between the control and experimental groups, 18 of which were differentially expressed, we selected ten circRNAs and performed qRT-PCR and Sanger sequencing to validate them. By GO and KEGG enrichment analysis, we found differentially expressed circRNAs that were mainly enriched in processes related to placental development and reproduction. Finally, using bioinformatics, we predicted miRNAs and mRNAs that circ-Mbd5 and circ-Ash1l might regulate and constructed circRNA-miRNA-mRNA networks involving genes associated with ASD, suggesting that circRNAs might regulate the occurrence of ASD.

Unique regulatory roles of ncRNAs changed by PM2.5 in human diseases

PM_2.5 is a type of particulate matter with an aerodynamic diameter smaller than 2.5 µm, and exposure to PM_2.5 can adversely damage human health. PM_2.5 may impair health through oxidative stress, inflammatory reactions, immune function alterations and chromosome or DNA damage. Through increasing in-depth studies, researchers have found that noncoding RNAs (ncRNAs), particularly microRNAs (miRNAs), circular RNAs (circRNAs) as well as long noncoding RNAs (lncRNAs), might play significant roles in PM_2.5-related human diseases via some of the abovementioned mechanisms. Therefore, in this review, we mainly discuss the regulatory function of ncRNAs altered by PM_2.5 in human diseases and summarize the potential molecular mechanisms. The findings reveal that these ncRNAs might induce or promote diseases via inflammation, the oxidative stress response, cell autophagy, apoptosis, cell junction damage, altered cell proliferation, malignant cell transformation, disruption of synaptic function and abnormalities in the differentiation and status of immune cells. Moreover, according to a bioinformatics analysis, the altered expression of potential genes caused by these ncRNAs might be related to the development of some human diseases. Furthermore, some ncRNAs, including lncRNAs, miRNAs and circRNAs, or processes in which they are involved may be used as biomarkers for relevant diseases and potential targets to prevent these diseases. Additionally, we performed a meta-analysis to identify more promising diagnostic ncRNAs as biomarkers for related diseases.

Lnc-IL7R alleviates PM2.5-mediated cellular senescence and apoptosis through EZH2 recruitment in chronic obstructive pulmonary disease

BACKGROUND

Long-term exposure to PM_2.5 (particulate matter with an aerodynamic diameter of ≤ 2.5 μm) is associated with pulmonary injury and emphysema in patients with chronic obstructive pulmonary disease (COPD). We investigated mechanisms through which the long noncoding RNA lnc-IL7R contributes to cellular damage by inducing oxidative stress in COPD patients exposed to PM_2.5.

METHODS

Associations of serum lnc-IL7R levels with lung function, emphysema, and previous PM_2.5 exposure in COPD patients were analyzed. Reactive oxygen species and lnc-IL7R levels were measured in PM_2.5-treated cells. The levels of lnc-IL7R and cellular senescence-associated genes, namely p16^INK4a and p21^CIP1/WAF1, were determined through lung tissue section staining. The effects of p16^INK4a or p21^CIP1/WAF1 regulation were examined by performing lnc-IL7R overexpression and knockdown assays. The functions of lnc-IL7R-mediated cell proliferation, cell cycle, senescence, colony formation, and apoptosis were examined in cells treated with PM_2.5. Chromatin immunoprecipitation assays were conducted to investigate the epigenetic regulation of p21^CIP1/WAF1.

RESULTS

Lnc-IL7R levels decreased in COPD patients and were negatively correlated with emphysema or PM_2.5 exposure. Lnc-IL7R levels were upregulated in normal lung epithelial cells but not in COPD cells exposed to PM_2.5. Lower lnc-IL7R expression in PM_2.5-treated cells induced p16^INK4a and p21^CIP1/WAF1 expression by increasing oxidative stress. Higher lnc-IL7R expression protected against cellular senescence and apoptosis, whereas lower lnc-IL7R expression augmented injury in PM_2.5-treated cells. Lnc-IL7R and the enhancer of zeste homolog 2 (EZH2) synergistically suppressed p21^CIP1/WAF1 expression through epigenetic modulation.

CONCLUSION

Lnc-IL7R attenuates PM_2.5-mediated p21^CIP1/WAF1 expression through EZH2 recruitment, and its dysfunction may augment cellular injury in COPD.

Particulate Matters Affecting lncRNA Dysregulation and Glioblastoma Invasiveness: In Silico Applications and Current Insights

With a reported rise in global air pollution, more than 50% of the population remains exposed to toxic air pollutants in the form of particulate matters (PMs). PMs, from various sources and of varying sizes, have a significant impact on health as long-time exposure to them has seen a correlation with various health hazards and have also been determined to be carcinogenic. In addition to disrupting known cellular pathways, PMs have also been associated with lncRNA dysregulation-a factor that increases predisposition towards the onset or progression of cancer. lncRNA dysregulation is further seen to mediate glioblastoma multiforme (GBM) progression. The vast array of information regarding cancer types including GBM and its various precursors can easily be obtained via innovative in silico approaches in the form of databases such as GEO and TCGA; however, a need to obtain selective and specific information correlating anthropogenic factors and disease progression-in the case of GBM-can serve as a critical tool to filter down and target specific PMs and lncRNAs responsible for regulating key cancer hallmarks in glioblastoma. The current review article proposes an in silico approach in the form of a database that reviews current updates on correlation of PMs with lncRNA dysregulation leading to GBM progression.

Correlation between lung cancer markers and air pollutants in western China population

The relationship between serum lung cancer markers and the air pollution remains unclear. To further reveal the correlation between air pollutants and lung cancer, a retrospective analysis of 446,032 asymptomatic healthy people and symptomatic healthy people from the Health Management Center of the First Affiliated Hospital of Chongqing Medical University from 2014 to 2019 was performed. The distribution characteristics of serum lung cancer markers, cancer embryo antigens (CEA), cytokeratin 19 fragment (CYFRA211), squamous cell carcinoma antigen (SCC), and nerve-specific enolase (NSE) was analyzed in these population. Two independent sample man-Whitney U test was used to analyze the correlation of lung cancer markers and age, and a Chi-square test was used to analyze the relationship between lung cancer markers and gender. The daily change trend was profiled for six main air quality indicators PM₁₀, PM_2.5, SO₂, NO₂, CO, O₃ during the same period. The correlation between lung markers and air pollutants was investigated by Spearman and multiple linear regression. The results showed that CYFRA211 had the highest excess rate in the screening population. There were differences in the number of cases with concentrated expression of lung cancer markers in the different age groups. Among them, the people with NSE exceeding the standard were the youngest, and most of them were 40-55 years old. Besides SCC, the expression levels of other markers increased with age, and the expression levels of the four markers in males were significantly higher than those in females. Although the levels of PM₁₀ and PM_2.5 exceeded the WHO standard (World Health Organization. 2011), they were not correlated with lung cancer markers. Multiple comparisons showed that the air pollutants SO₂ and CYFRA211, as well as NO₂ and NSE were closely related, but there was no significant linear relationship between CEA, SCC, and air pollutants. In conclusion, among the four lung cancer markers, CYFRA211 had the highest abnormal excess rate in total screening population, and the expression levels of these markers varied by gender and age, with males showing significantly higher expression levels than females, and they increased significantly with age except for SCC. The differential expression of these lung cancer markers may provide more strategies for lung cancer screening in the corresponding population. Lung cancer markers, CYFRA211 and NSE, can be used as sensitive biomarkers for exposure to certain air pollutants and provide references for the prevention and management of air pollution.

Polycyclic aromatic hydrocarbons, long non-coding RNA expression, and DNA damage in coke oven workers

Exposure to polycyclic aromatic hydrocarbons (PAHs) was associated with DNA damage, while the roles of long non-coding RNAs (lncRNAs) in the associations were unclear. We aimed to assess the association of lncRNA NR_024564 with urinary monohydroxy PAHs (OH-PAHs) and DNA damage among 332 coke oven workers. We determined 12 OH-PAHs by gas chromatography-mass spectrometry, and the expression level of NR_024564 by droplet digital RT-PCR and DNA damage by the comet assay. In total participants, we found that NR_024564 was not significantly associated with OH-PAHs or comet parameters. However, among workers with ≥ 20 working years, multiple OH-PAHs including urinary 1-hydroxyphenanthrene (1-OHPh), 2-OHPh, 3-OHPh, 9-OHPh, 1‑hydroxypyrene, and total PAH metabolites were related to increased comet parameters. Moreover, NR_024564 was significantly associated with 2-OHPh and four comet parameters. Each 1% increase in 2-OHPh was associated with 0.35% reduction (95% CI: 0.16%, 0.55%) in NR_024564 (P-_FDR = 0.005), and 2-OHPh was marginally interacted with working years in relation to NR_024564 decrease. Also, each 1% increment of NR_024564 was related to 0.04-0.13% decrease of Olive tail moment, percent DNA in the comet tail, tail length, and tail moment (all P-_FDR < 0.05). Furthermore, low NR_024564 level combined with high levels of 1-OHPh and 2-OHPh or ≥ 20 working years was positively associated with the comet parameters among the total participants. Our results indicated that NR_024564 might be linked to the adverse associations of PAHs with the DNA damage of coke oven workers who worked for ≥ 20 years.

The human long noncoding RNAs CoroMarker, MALAT1, CDR1as, and LINC00460 in whole blood of individuals after controlled short-term exposure with ultrafine metal fume particles at workplace conditions, and in human macrophages in vitro

Background

Short-term inhalation of occupationally relevant ultrafine zinc/copper (Zn/Cu) containing welding fumes has been shown to induce subclinical systemic inflammation, associated with an elevated risk for cardiovascular diseases. The involvement of noncoding RNAs (lncRNAs) in this setting is currently unknown. However, lncRNAs have been reported to fulfill essential roles in, e.g., cardiovascular diseases, inflammation, infectious diseases, and pollution-related lung disorders.

Methods

In this study, the specific lncRNAs levels of the 4 lncRNAs CoroMarker, MALAT1, CDR1as and LINC00460 were determined by RT-qPCR in THP-1 macrophages exposed to Zn/Cu metal fume suspensions for 1, 2, and 4 hours in vitro. Furthermore, 14 subjects were exposed to Zn/Cu containing welding fumes (at 2.5 mg/m³) for 6 hours. Before, 6, 10, and 29 hours after exposure start, whole blood cell lncRNAs levels were determined by RT-qPCR.

Results

In THP-1 macrophages, we observed a 2.3-fold increase of CDR1as at 1 h (Wilcoxon p = 0.03), a non-significant increase of CoroMarker at 1 h, and an increase of LINC00460 at 2 h (p = 0.03) and at 4 h (p = 0.06). In whole blood cells, we determined a non-significant upregulation of CDR1as at 6 h (p = 0.2), a significant downregulation of CoroMarker at 6 h (p = 0.04), and a significant upregulation of LINC00460 levels at 10 h (p = 0.04) and 29 h (p = 0.04). MALAT-1 remained unchanged in both settings.

Conclusion

The orientation of regulation of the lncRNAs is (except for CoroMarker) similar in the in vitro and in vivo experiments and in line with their described functions. Therefore, these results, e.g. the upregulation of the potential risk marker for cardiovascular diseases, CDR1as, contribute to understanding the underlying mechanisms of Zn/Cu-induced subclinical inflammation in metal workers.

Role of air pollutants in airway epithelial barrier dysfunction in asthma and COPD

Chronic exposure to environmental pollutants is a major contributor to the development and progression of obstructive airway diseases, including asthma and COPD. Understanding the mechanisms underlying the development of obstructive lung diseases upon exposure to inhaled pollutants will lead to novel insights into the pathogenesis, prevention and treatment of these diseases. The respiratory epithelial lining forms a robust physicochemical barrier protecting the body from inhaled toxic particles and pathogens. Inhalation of airborne particles and gases may impair airway epithelial barrier function and subsequently lead to exaggerated inflammatory responses and airway remodelling, which are key features of asthma and COPD. In addition, air pollutant-induced airway epithelial barrier dysfunction may increase susceptibility to respiratory infections, thereby increasing the risk of exacerbations and thus triggering further inflammation. In this review, we discuss the molecular and immunological mechanisms involved in physical barrier disruption induced by major airborne pollutants and outline their implications in the pathogenesis of asthma and COPD. We further discuss the link between these pollutants and changes in the lung microbiome as a potential factor for aggravating airway diseases. Understanding these mechanisms may lead to identification of novel targets for therapeutic intervention to restore airway epithelial integrity in asthma and COPD.

Exposure to air pollution induces airway epithelial barrier dysfunction through several mechanisms including increased oxidative stress, exaggerated cytokine responses and impaired host defence, which contributes to development of asthma and COPD. https://bit.ly/3DHL1CA

Involvement of m6A regulatory factor IGF2BP1 in malignant transformation of human bronchial epithelial Beas-2B cells induced by tobacco carcinogen NNK

Nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a Group 1 human carcinogen, as classified by the International Agency for Research of Cancer (IARC), and plays a significant role in lung carcinogenesis. However, its carcinogenic mechanism has not yet been fully elucidated. In this study, we performed colony formation assays, soft-agar assays, and tumor growth in nude mice to show that 100 mg/L NNK facilitates the malignant transformation of human bronchial epithelial Beas-2B cells. Transcriptome sequencing showed that insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), a post-transcriptional regulator, was differentially expressed in NNK-induced malignant transformed Beas-2B cells (2B-NNK cells). Small interfering RNA (SiRNA) was used to downregulate the expression of the IGF2BP1 gene. The reduction in protein expression, cell proliferation rate, and colony-forming ability and the increase in the apoptosis rate of Beas-2B cells transfected with the SiRNA indicated a role for IGF2BP1 in NNK-induced malignant transformation. IGF2BP1 is an N6-methyladenosine (m6A) regulatory factor, but it is not known whether its association with m6A mediates the malignant transformation of cells. Therefore, we measured the overall levels of m6A in Beas-2B cells. We found that the overall m6A level was lower in 2B-NNK cells, and knocking down IGF2BP1, the overall level of m6A was restored. Hence, we concluded that IGF2BP1 is involved in the NNK-induced malignant transformation of Beas-2B cells, possibly via m6A modification. This study therefore contributes novel insights into the environmental pathogenesis of lung cancer and the gene regulatory mechanisms of chemical carcinogenesis.

lncRNA AABR07005593.1 potentiates PM2.5-induced interleukin-6 expression by targeting MCCC1

BACKGROUND

Fine particle pollution, specifically pollution by fine particulate matter (PM_2.5), remains a significant concern in developing countries and plays an important role in the development and progression of respiratory diseases. Increasing evidences have demonstrated that long non-coding RNAs (lncRNAs) may act as vital molecules by binding to specific RNA-binding protein (RBP); however, their relationship with PM_2.5 pollution is largely unexplored.

OBJECTIVE

We investigated the association between lncRNA and respiratory system inflammation caused by PM_2.5.

METHODS

PM_2.5 components were detected by gas chromatography-mass spectrometry (GC-MS), inductively coupled plasma-mass spectrometry (ICP-MS), and ionic chromatography. We established an inflammation model of PM_2.5-induced toxicity in vivo (male and female SD rats, 0, 25, 50 and 100 mg/k PM_2.5, 1, 7 and 14 days, single non-invasive tracheal instillation) and in vitro (rat alveolar macrophage cell line (NR8383), 0, 50, 100, 200, 400 μM PM_2.5 for 24, 48, and 72 h). lncRNA high-throughput sequencing (lncRNA-seq) was used to investigate lncRNA profiles in PM_2.5-treated NR8383 cells, and RNA interference (RNAi) was applied to explore the function of the target lncRNA. The mechanisms associated with specific lncRNAs were explored using comprehensive identification of RNA-binding proteins by mass spectrometry (ChIRP-MS) and western blot.

RESULTS

PM_2.5-treated NR8383 cells and SD rats exhibited respiratory inflammation. lncRNA AABR07005593.1 was a pro-inflammatory factor that regulated IL-6 levels. Mechanistically, ChIRP-MS and western blot analyses revealed that highly expressed lncRNA AABR07005593.1 interacted with MCCC1 to involve in the activation of NF-κB pathway, and ultimately promoted the expression of IL-6.

CONCLUSION

This study demonstrated that PM_2.5 induced inflammation in vivo and in vitro. Furthermore, lncRNA AABR07005593.1 bound to MCCC1 to potentiated IL-6 expression. Therefore, lncRNA AABR07005593.1 may act as a potential biomarker for PM_2.5 inflammation.

Novel Insights Into MALAT1 Function as a MicroRNA Sponge in NSCLC

The long non-coding RNA metastasis-associated lung adenocarcinoma transcript-1 (MALAT1) was initially found to be overexpressed in early non-small cell lung cancer (NSCLC). Accumulating studies have shown that MALAT1 is overexpressed in the tissue or serum of NSCLC and plays a key role in its occurrence and development. In addition, the expression level of MALAT1 is significantly related to the tumor size, stage, metastasis, and distant invasion of NSCLC. Therefore, MALAT1 could be used as a biomarker for the early diagnosis, severity assessment, or prognosis evaluation of NSCLC patients. This review describes the basic properties and biological functions of MALAT1, focuses on the specific molecular mechanism of MALAT1 as a microRNA sponge in the occurrence and development of NSCLC in recent years, and emphasizes the application and potential prospect of MALAT1 in molecular biological markers and targeted therapy of NSCLC.

Research advances in pathogenic mechanisms underlying air pollution-induced ocular surface diseases

Background

The harmful effect of aerial fine particulate matter（PM2.5）has been a serious public health issue and has attracted worldwide attention, especially in developing countries.

Main Text

Numerous previous clinical and experimental studies have demonstrated that PM2.5 has a clear pathogenic effect on diseases related to the respiratory and cardiovascular systems. Recent researches have pointed out that PM2.5 plays a pivotal role in the occurrence and progression of ocular surface diseases. The current studies have shown that PM2.5 may promote the appearance of conjunctivitis, keratitis, blepharitis, dry eye, meibomian gland dysfunction（MGD） and other ocular surface diseases through regulating a series of mechanisms such as inflammation, immune reaction, oxidative stress, autophagy, cell migration, and epigenetics.

Conclusions

This review aims to summarize the current research progress on the pathogenic mechanism of PM2.5-related ocular surface diseases.

Polycyclic aromatic hydrocarbons associated long non-coding RNAs and heart rate variability in coke oven workers

Epidemiological studies have showed that polycyclic aromatic hydrocarbons (PAHs) were associated with heart rate variability (HRV), but the role of long non-coding RNAs (lncRNAs) in the association is unknown. We aimed to identify PAHs-related lncRNAs and assess their associations with HRV among coke oven workers. Differential lncRNAs expression between 12 exposed workers and 12 controls was tested by Human 8X60k LncRNA Arrays in discovery stage, then selected NR_024564 was validated in 353 workers using droplet digital RT-PCR. Microarray results showed that 1234 lncRNAs were downregulated with 805 lncRNAs upregulated in exposed group (≥ 2-fold change). In validation stage, no significant association was observed between NR_024564 and PAH exposure or HRV in total subjects, while urinary 2-hydroxyfluorene (2-OHFlu) was inversely related to root mean square successive difference (RMSSD). However, in current smokers, NR_024564 was inversely related to urinary 2-OHFlu, 2-hydroxyphenanthrene, 1-hydroxypyrene (1-OHP), and total PAHs metabolites (ΣOH-PAHs), of which 1-OHP accounted for the strongest estimation for interaction with smoking status (P_interaction = 0.011). Also, the positive associations of NR_024564 with RMSSD and high frequency power showed an interaction with smoking status (P_interaction = 0.034 and 0.023, respectively). Also, urinary 2-OHFlu and ΣOH-PAHs were inversely associated with RMSSD in current smokers. In addition, elevated NR_024564 was dose-responsive related to increased RMSSD in above high-PAHs groups among smokers (all P_trend < 0.05). Our results revealed that NR_024564 and its interactions with smoking status might act as novel mechanisms regulating the adverse effects of PAHs on HRV.

lncRNA SOX2-OT ceRNA network enhances the malignancy of long-term PM2.5-exposed human bronchial epithelia

Exposure to fine particulate matter (PM_2.5) in outdoor air is carcinogenic and associated with the development of lung cancer; however, the underlying mechanism remains unclear. In the present study, the profiles of lncRNA, microRNA and mRNA expression profiles in human bronchial epithelia (HBE) following exposure to PM_2.5, diesel exhaust particles (DEPs), or aluminum oxide nanoparticles (Al₂O₃ NPs) were explored by microarray to reveal the lncRNA-microRNA-mRNA network participating in the malignant transformation of HBE cells following long-term PM_2.5 exposure. The results showed that lncRNA SOX2 overlapping transcript (SOX2-OT) was significantly induced in HBE cells exposed to PM_2.5, DEPs, or Al₂O₃ NPs, acting as a sponge to microRNA-345-5p, which subsequently increased the expression levels of epidermal growth factor receptor (EGFR). EGFR is a therapeutic target in non-small cell lung cancer. Here, we found that SOX2-OT is an upstream trigger of EGFR in HBE cells during long-term PM_2.5 exposure. Importantly, SOX2-OT knockdown effectively reduced the colony formation and migration capacities of HBE cells, compared to the wild type control. Collectively, SOX2-OT/microRNA-345-5p/EGFR is a ceRNA mechanism underlying the malignant transformation of bronchial epithelia exposed to PM_2.5, which improves our understanding of the association between ambient PM_2.5 exposure and the development of lung cancer.

The identify role and molecular mechanism of the MALAT1/hsa-mir-20b-5p/TXNIP axis in liver inflammation caused by CHB in patients with chronic HBV infection complicated with NAFLD

BACKGROUND/AIMS

To identify the inflammatory damage caused by chronic hepatitis B (CHB) in patients of chronic hepatitis B virus (HBV) infection complicated with non-alcoholic fatty liver disease (NAFLD), then guiding clinicians to carry out antiviral treatment.

METHODS

According to the pathological features of liver biopsy, treatment-naïve obese patients of chronic HBV infection complicated with NAFLD who had elevated alanine transaminase (ALT) were divided into CHB group and NASH group. Transcriptome chips were used to analyze the expression profiles of long non-coding RNA (lncRNA) and mRNA in liver puncture tissues from the two groups. The chip data of CHB and NASH groups were analyzed for differential expression analysis, gene function analysis, signal pathway analysis, target gene prediction and competing endogenous RNAs (ceRNA) network analysis.

RESULTS

By comparing CHB group with NASH group, a total of 44 differentially expressed lncRNAs and 567 differentially expressed mRNAs were screened. GO analysis predicted that the differentially expressed mRNAs may affect monooxygenase activity and oxidoreductase activity. KEGG analysis predicted that the differentially expressed mRNAs may be related to signaling pathways involved in oxidative phosphorylation, phagosomes, and NAFLD. Differential analysis of lncRNA shown that the expression of metastasis associated in lung adenocarcinoma transcript 1 (MALAT1) in CHB group was significantly upregulated. Subsequently, through target gene prediction and ceRNA network analysis, we found thioredoxin interacting protein (TXNIP), which was significantly upregulated in the CHB group and had a ceRNA relationship with MALAT1. It is predicted that there may be a ceRNA regulation relationship of MALAT1/hsa-miR- 20b-5p/TXNIP.

CONCLUSION

The MALAT1/hsa-miR-20b-5p/TXNIP axis may mediate CHB-induced inflammatory damage in chronic HBV infection complicated with NAFLD, and the mechanism may be related to the activation of NLRP3 inflammatory bodies and downstream inflammatory responses.

lncRNA Gm16410 Mediates PM2.5-Induced Macrophage Activation via PI3K/AKT Pathway

PM₂.₅ refers to atmospheric particulate matters with a diameter of less than 2.5 μm. The deposit of PM₂.₅ in lung cells can cause oxidative stress, leading to changes in macrophage polarity, which can subsequently cause pulmonary inflammation. Long-chain non-coding RNA (lncRNA) is a class of transcripts that regulate biological processes through multiple mechanisms. However, the role of lncRNA in PM₂.₅-induced lung inflammation has not been established. In this study, the biological effects and associated mechanism of lncRNA in PM₂.₅-induced change in macrophage polarity were investigated. The lncRNA-mediated PM₂.₅-induced macrophage inflammation and lung inflammation-associated injury were also determined. Mice were exposed to chronic levels of PM₂.₅, and changes in the expression of lncRNA in the lung were measured by lncRNA microarray. lncRNAs that showed significant changes in expression in response to PM₂.₅ were identified. lncRNA showing the biggest change was subjected to further analysis to determine its functional roles and mechanisms with respect to macrophage activation. The result showed that a significant reduction in expression of one lncRNA, identified as lncGm16410, was observed in the lung of mice and RAW264.7 cells following exposure to PM₂.₅. lncGm16410 suppressed PM₂.₅-induced macrophage activation via the SRC protein-mediated PI3K/AKT signaling pathway. PM₂.₅ promoted lung inflammation by downregulating the expression of lncGm16410, enhancing the activation of macrophages. Thus, lncGm16410 might provide new insight into the prevention of PM₂.₅ injury.

Long non-coding RNA NORAD upregulation induced by airborne particulate matter (PM10) exposure leads to aneuploidy in A549 lung cells

Air pollution is a worldwide problem that affects human health predominantly in the largest cities. Particulate matter of 10 μm or less in diameter (PM₁₀) is considered a risk factor for multiple diseases, including lung cancer. The long non-coding RNA NORAD and the components of the spindle assembly checkpoint (SAC) ensure proper chromosomal segregation. Alterations in the SAC cause aneuploidy, a feature associated with carcinogenesis. In this study, we demonstrated that PM₁₀ treatment increased the expression levels of NORAD as well as those of SAC components mitotic arrest deficient 1 (MAD1L1), mitotic arrest deficient 2 (MAD2L1), BubR1 (BUB1B), aurora B (AURKB), and survivin (BIRC5) in the lung A549 cell line. We also demonstrated that MAD1L1, MAD2L1, and BUB1B expression levels were reduced when cells were transfected with small interfering RNAs (siRNAs) against NORAD. Interestingly, the expression levels of AURKB and BIRC5 (survivin) were not affected by transfection with NORAD siRNAs. Cells treated with PM₁₀ exhibited a decrease in mitotic arrest and an increase in micronuclei frequency in synchronized A549 cells. PM₁₀ exposure induced aneuploidy events as a result of SAC deregulation. We also observed a reduction in the protein levels of Pumilio 1 after PM₁₀ treatment. Our results provide novel clues regarding the effect of PM₁₀ in the generation of chromosomal instability, a phenotype observed in lung cancer cells.

Atmospheric fine particulate matter and epithelial mesenchymal transition in pulmonary cells: state of the art and critical review of the in vitro studies

Exposure to fine particulate matter (PM_2.5) has been associated with several diseases including asthma, chronic obstructive pulmonary disease (COPD) and lung cancer. Mechanisms such as oxidative stress and inflammation are well-documented and are considered as the starting point of some of the pathological responses. However, a number of studies also focused on epithelial-mesenchymal transition (EMT), which is a biological process involved in fibrotic diseases and cancer progression notably via metastasis induction. Up until now, EMT was widely reported in vivo and in vitro in various cell types but investigations dealing with in vitro studies of PM_2.5 induced EMT in pulmonary cells are limited. Further, few investigations combined the necessary endpoints for validation of the EMT state in cells: such as expression of several surface, cytoskeleton or extracellular matrix biomarkers and activation of transcription markers and epigenetic factors. Studies explored various cell types, cultured under differing conditions and exposed for various durations to different doses. Such unharmonized protocols (1) might introduce bias, (2) make difficult comparison of results and (3) preclude reaching a definitive conclusion regarding the ability of airborne PM_2.5 to induce EMT in pulmonary cells. Some questions remain, in particular the specific PM_2.5 components responsible for EMT triggering. The aim of this review is to examine the available PM_2.5 induced EMT in vitro studies on pulmonary cells with special emphasis on the critical parameters considered to carry out future research in this field. This clarification appears necessary for production of reliable and comparable results.

PM2.5, Fine Particulate Matter: A Novel Player in the Epithelial-Mesenchymal Transition?

Epithelial-mesenchymal transition (EMT) refers to the conversion of epithelial cells to mesenchymal phenotype, which endows the epithelial cells with enhanced migration, invasion, and extracellular matrix production abilities. These characteristics link EMT with the pathogenesis of organ fibrosis and cancer progression. Recent studies have preliminarily established that fine particulate matter with an aerodynamic diameter of less than 2.5 μm (PM_2.5) is correlated with EMT initiation. In this pathological process, PM_2.5 particles, excessive reactive oxygen species (ROS) derived from PM_2.5, and certain components in PM_2.5, such as ions and polyaromatic hydrocarbons (PAHs), have been implicated as potential EMT mediators that are linked to the activation of transforming growth factor β (TGF-β)/SMADs, NF-κB, growth factor (GF)/extracellular signal-regulated protein kinase (ERK), GF/phosphatidylinositol 3-kinase (PI3K)/Akt, wingless/integrated (Wnt)/β-catenin, Notch, Hedgehog, high mobility group box B1 (HMGB1)-receptor for advanced glycation end-products (RAGE), and aryl hydrocarbon receptor (AHR) signaling cascades and to cytoskeleton rearrangement. These pathways directly and indirectly transduce pro-EMT signals that regulate EMT-related gene expression in epithelial cells, finally inducing the characteristic alterations in morphology and functions of epithelia. In addition, novel associations between autophagy, ATP citrate lyase (ACLY), and exosomes with PM_2.5-induced EMT have also been summarized. However, some debates and paradoxes remain to be consolidated. This review discusses the potential molecular mechanisms underlying PM_2.5-induced EMT, which might account for the latent role of PM_2.5 in cancer progression and fibrogenesis.

Divergently expressed RNA identification and interaction prediction of long non-coding RNA and mRNA involved in Hu sheep hair follicle

Hair follicles are the basis of the formation of Hu sheep pattern. This study was to employ whole transcriptome sequencing to screen differentially expressed long non-coding RNAs (lncRNAs) between three wave patterns in lambskin. In this study, three groups of 2-day-old Hu sheep were selected from full-sib individuals that included small, medium, and large waves, and hair follicle tissues were collected from dorsal side of Hu sheep. LncRNA and mRNA expression profiles were analyzed by whole transcriptome sequencing technology. 33, 31, and 41 differentially expressed lncRNAs were selected between large and medium, medium and small, and large and small, respectively. 458, 481, and 498 differentially expressed mRNAs were found between large and medium, medium and small, and large and small, respectively, by RNA-seq analysis. qRT-PCR results of 16 randomly selected lncRNAs and mRNAs were similar to the sequencing results. Correlation analysis of lncRNA and mRNA expression showed that, several lncRNAs may be enriched for hair follicle such as Wnt, mTOR, Notch signaling pathways. Our results aid in excavation of mRNAs and lncRNAs in hair follicle, and providing a basis for future study on pattern formation mechanisms.

Aryl hydrocarbon receptor mediates the cardiac developmental toxicity of EOM from PM2.5 in P19 embryonic carcinoma cells

Ambient fine particulate matter (PM_2.5) has been found to be associated with congenital heart defects, but the molecular mechanisms remain to be elucidated. Our previous study revealed that extractable organic matter (EOM) from PM_2.5 exerted cardiac developmental toxicity in zebrafish embryos. The aim of the current study is to explore the effects of EOM on cardiac differentiation of P19 mouse embryonic carcinoma stem cells. We found that EOM at 10 μg/ml (a non-cytotoxic dose level) significantly reduced the proportion of cardiac muscle troponin (cTnT) positive cells and the percentage of spontaneously beating embryoid bodies, indicating a severe inhibition of cardiac differentiation. Immunofluorescence and qPCR data demonstrated that EOM increased the expression levels of the aryl hydrocarbon receptor (AhR) and its target gene Cyp1A1 and diminished the expression level of β-catenin. Furthermore, EOM treatment significantly upregulated cell proliferation rate and elevated the percentage of γH2A.X positive cells without affecting apoptosis. It is worth noting that the EOM-induced changes in gene expression, cellular proliferation and DNA double strain breaks were attenuated by the AhR antagonist CH223191. In conclusion, our data indicate that AhR mediates the inhibitory effects of EOM (from PM_2.5) on the cardiac differentiation of P19 cells.

Changes in long non-coding RNA expression profiles related to the antagonistic effects of Escherichia coli F17 on lamb spleens

Sheep colibacillosis is one of the most common bacterial diseases found at large-scale sheep farms. The aim of this study was to employ RNA-seq to screen differentially expressed (DE) long non-coding RNAs (lncRNAs) that impart antagonistic or sensitive effects on Escherichia coli F17. In this study, individuals who had antagonistic or sensitive responses to E. coli F17 were identified by feeding E. coli F17 strains to Hu lambs. The sensitive group had higher levels of intestinal bacteria than that in the antagonistic group (P < 0.05), the jejunum showed various levels of mucosal tissue damage and had a dark colour, and disintegration of part of the small intestinal villi was observed. Totals of 34 DE lncRNAs and 703 DE mRNAs in two groups were identified. qRT-PCR results for 12 randomly selected DE lncRNAs and DE mRNAs were consistent with the RNA-seq data. Gene Ontology (GO), KEGG Pathway enrichment and lncRNA-mRNA interaction analyses identified 6 co-expressed genes, namely, MYO1G, TIMM29, CARM1, ADGRB1, SEPT4, and DESI2. This is the first study that has performed expression profiling of lncRNAs in the spleen of antagonistic and sensitive lambs. The identification of DE lncRNAs can facilitate investigations into the molecular mechanism underlying resistance to diarrhoea in sheep.

miRNAs deregulation in lung cells exposed to airborne particulate matter (PM10) is associated with pathways deregulated in lung tumors

Particulate matter (PM) is an environmental pollutant that has been associated with an increased risk for lung cancer. PM exposure induces cellular alterations and the deregulation of cell signaling pathways. However other mechanisms such as microRNAs deregulation, might be involved in the development and progression of some types of epithelial cancer. The aim of this work was to evaluate miRNA expression in epithelial lung cells after exposure to PM₁₀ and to identify the possible gene targets of deregulated miRNAs. We measured the expression of 2538 miRNAs using a microarray platform after 72 h of PM₁₀ exposure; the potential biological function was inferred with bioinformatics analysis and we validated the relative expression of 10 selected miRNAs with real-time PCR. We found that the expression of 74 miRNAs was significantly changed: 45 miRNAs were downregulated and were involved in proliferation, cell cycle, cytoskeleton modification and autophagy; meanwhile, 29 miRNAs related to apoptosis, DNA damage repair and xenobiotic metabolism were upregulated.

Emerging roles of long non-coding RNAs in the toxicology of environmental chemicals

Environmental chemicals (ECs) are drawing great attention to their effects on health and their toxicological mechanisms are being investigated. Long non-coding RNA (lncRNA) is a class of RNA with more than 200 nucleotides and does not have protein coding potential. Recently, it is emerging as a star molecule that participates in a wide range of physiological and pathological processes. It has been reported to be abnormally expressed in diseases. As an epigenetic factor, lncRNAs play an important role in the response of organisms to environmental stress. Their roles in the toxicity of ECs are being identified. Altered expression profiles of lncRNAs have been explored after exposure to ECs. Various kinds of ECs are reported to disturb the expression of lncRNAs in vitro and in vivo. Then, dysregulated lncRNAs can affect the expression of target genes directly or indirectly via regulating the level of microRNAs. The network among lncRNAs, microRNAs and mRNAs can initiate or impede specific signaling pathway and lead to adverse outcome upon exposure to ECs. Recovery of the lncRNAs level by overexpression or knockdown technology diminished the effect induced by ECs. In the review, biological roles of lncRNAs are depicted. The lncRNAs involved in the toxicology are summarized. Types of ECs that have been reported to affect the expression of lncRNAs are categorized. The interaction between various types of ECs and lncRNAs is discussed.

Rosiglitazone inhibits PM2.5-induced cytotoxicity in human lung epithelial A549 cells

Background

Exposure to fine particulate matter <2.5 µm in diameter (PM2.5) leads to global adverse health effects, including increases in morbidity and mortality of respiratory diseases. PM2.5 increases production of reactive oxygen species (ROS) in the lung, which further lead to oxidative stress, cell apoptosis and cell death. According to results of previous studies, oxidative stress and subsequent cell apoptosis can be reduced by peroxisome proliferator-activated receptor gamma (PPARγ) in various cell types, however, its role in oxidative stress-related cell apoptosis caused by PM2.5 in respiratory systems is unclear.

Methods

Human lung alveolar epithelial A549 cells were exposed to PM2.5 with or without rosiglitazone (an agonist of PPARγ) treatment. Cellular apoptosis and intracellular oxidative stress were determined by flow cytometry based on FITC Annexin V and DCFH-DA fluorescence, respectively. Western blot was conducted to determine the expression of Bax, Bcl2, PPARγ, P-ERK1/2, ERK1/2, P-STAT3, and STAT3.

Results

PPARγ was downregulated in PM2.5-treated A549 cells, and application of rosiglitazone reduced PM2.5-mediated ROS generation and cell apoptosis. In addition, our results indicated that rosiglitazone treatment suppressed PM2.5-induced ERK1/2 and STAT3 activation.

Conclusions

Collectively, these data suggested that rosiglitazone protects against PM2.5-induced ROS production and cell apoptosis and represses activation of ERK1/2 and STAT3 signaling in A549 cells. Our results indicated that rosiglitazone is a potential therapeutic agent for PM2.5-induced lung diseases.