Amphiregulin potentiates airway inflammation and mucus hypersecretion induced by urban particulate matter via the EGFR-PI3Kα-AKT/ERK pathway

Cell Culture Differentiation and Proliferation Conditions Influence the In Vitro Regeneration of the Human Airway Epithelium

The human airway mucociliary epithelium can be recapitulated in vitro using primary cells cultured in an air-liquid interface (ALI), a reliable surrogate to perform pathophysiological studies. As tremendous variations exist among media used for ALI-cultured human airway epithelial cells, the aim of our study was to evaluate the impact of several media (BEGM, PneumaCult, Half & Half, and Clancy) on cell type distribution using single-cell RNA sequencing and imaging. Our work revealed the impact of these media on cell composition, gene expression profile, cell signaling, and epithelial morphology. We found higher proportions of multiciliated cells in PneumaCult-ALI and Half & Half, stronger EGF signaling from basal cells in BEGM-ALI, differential expression of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry factor ACE2, and distinct secretome transcripts depending on the media used. We also established that proliferation in PneumaCult-Ex Plus favored secretory cell fate, showing the key influence of proliferation media on late differentiation epithelial characteristics. Altogether, our data offer a comprehensive repertoire for evaluating the effects of culture conditions on airway epithelial differentiation and will aid in choosing the most relevant medium according to the processes to be investigated, such as cilia, mucus biology, or viral infection. We detail useful parameters that should be explored to document airway epithelial cell fate and morphology.

Particulate matter 2.5 accelerates aging: Exploring cellular senescence and age-related diseases

Exposure to Particulate matter 2.5 (PM2.5) accelerates aging, causing declines in tissue and organ function, and leading to diseases such as cardiovascular, neurodegenerative, and musculoskeletal disorders. PM2.5 is a major environmental pollutant and an exogenous pathogen in air pollution that is now recognized as an accelerator of human aging and a predisposing factor for several age-related diseases. In this paper, we seek to elucidate the mechanisms by which PM2.5 induces cellular senescence, such as genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, and mitochondrial dysfunction, and age-related diseases. Our goal is to increase awareness among researchers within the field of the toxicity of environmental pollutants and to advocate for personal and public health initiatives to curb their production and enhance population protection. Through these endeavors, we aim to promote longevity and health in older adults.

New markers in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), a global healthcare and socioeconomic burden, is a multifaceted respiratory disorder that results in substantial decline in health status and life quality. Acute exacerbations of the disease contribute significantly to increased morbidity and mortality. Consequently, the identification of reliable and effective biomarkers for rapid diagnosis, prediction, and prognosis of exacerbations is imperative. In addition, biomarkers play a crucial role in monitoring responses to therapeutic interventions and exploring innovative treatment strategies. Although established markers such as CRP, fibrinogen and neutrophil count are routinely used, a universal marker is lacking. Fortunately, an increasing number of studies based on next generation analytics have explored potential biomarkers in COPD. Here we review those advances and the need for standardized validation studies in the appropriate clinical setting.

Active AKT2 stimulation of SREBP1/SCD1-mediated lipid metabolism boosts hepatosteatosis and cancer

Due to soared obesity population worldwide, hepatosteatosis is becoming a major risk factor for hepatocellular carcinoma (HCC). Undertaken molecular events during the progression of steatosis to liver cancer are thus under intensive investigation. In this study, we demonstrated that high-fat diet potentiated mouse liver AKT2. Hepatic AKT2 hyperactivation through gain-of-function mutation of Akt2 (Akt2E17K) caused spontaneous hepatosteatosis, injury, inflammation, fibrosis, and eventually HCC in mice. AKT2 activation also exacerbated lipopolysaccharide and D-galactosamine hydrochloride-induced injury/inflammation and N-Nitrosodiethylamine (DEN)-induced HCC. A positive correlation between AKT2 activity and SCD1 expression was observed in human HCC samples. Activated AKT2 enhanced the production of monounsaturated fatty acid which was dependent on SREBP1 upregulation of SCD1. Blockage of active SREBP1 and ablation of SCD1 reduced steatosis, inflammation, and tumor burden in DEN-treated Akt2E17K mice. Therefore, AKT2 activation is crucial for the development of steatosis-associated HCC which can be treated with blockage of AKT2-SREBP1-SCD1 signaling cascade.

Impact of particulate air pollution on airway injury and epithelial plasticity; underlying mechanisms

Air pollution plays an important role in the mortality and morbidity of chronic airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD). Particulate matter (PM) is a significant fraction of air pollutants, and studies have demonstrated that it can cause airway inflammation and injury. The airway epithelium forms the first barrier of defense against inhaled toxicants, such as PM. Airway epithelial cells clear airways from inhaled irritants and orchestrate the inflammatory response of airways to these irritants by secreting various lipid mediators, growth factors, chemokines, and cytokines. Studies suggest that PM plays an important role in the pathogenesis of chronic airway diseases by impairing mucociliary function, deteriorating epithelial barrier integrity, and inducing the production of inflammatory mediators while modulating the proliferation and death of airway epithelial cells. Furthermore, PM can modulate epithelial plasticity and airway remodeling, which play central roles in asthma and COPD. This review focuses on the effects of PM on airway injury and epithelial plasticity, and the underlying mechanisms involving mucociliary activity, epithelial barrier function, airway inflammation, epithelial-mesenchymal transition, mesenchymal-epithelial transition, and airway remodeling.

Disease burden of COPD attributable to PM2.5 in China, Japan and South Korea from 1990 to 2019: a comparative study based on Global Burden of Disease Study 2019

OBJECTIVE

We hope to reveal the changing trends of chronic obstructive pulmonary disease (COPD) burden attributable to particulate matter pollution (PM2.5) and its age, period and cohort effects in China, Japan and Korea.

DESIGN

We analysed the trend of COPD disease burden attributable to PM2.5 from 1990 to 2019 based on the latest Global Burden of Disease Database (GBD 2019) using JoinPoint model and analysed the effect of age, period and cohort on COPD burden attributable to PM2.5 in China, Japan and Korea from 1990 to 2019 using age-period-cohort model (model).

SETTING

GBD data from 1990 to 2019.

PARTICIPANTS

Data were publicly available and individuals were not involved.

MAIN OUTCOMES

Outcomes included the age standardised mortality rate (ASMR), the age-standardised disability-adjusted life year (DALY), average annual per cent change (AAPC), net drift, local drift, longitudinal age curves, period (cohort) rate ratios, age (period, cohort) bias coefficient.

RESULTS

From 1990 to 2019, the ASMR of COPD attributable to PM2.5 in China (AAPC=-5.862), Japan (AAPC=-1.715) and Korea (AAPC=-1.831) showed a downward trend. The age-standardised DALY of COPD attributable to PM2.5 in China (AAPC=-5.821), Japan (AAPC=-1.39) and Korea (AAPC=-1.239) showed a downward trend. Mortality of COPD attributable to PM2.5 increased slowly with age in Korea and Japan. Mortality of COPD attributable to PM2.5 in China decreased after rising (95% CI: 404.66 to 466.01). Mortality of COPD attributable to PM2.5 decreased over time in China and Korea, while it increased in Japan from 2015 to 2019. In China and Japan, mortality of COPD attributable to PM2.5 was approximately lower the later the birth, while in Korea it decreased after an increase (95% CI: 2.13 to 2.40) in the 1900-1910.

CONCLUSIONS

Most COPD burden attributable to PM2.5 is on the decline; COPD mortality attributable to PM2.5 both increased with age and decreased with time and cohort. Countries with high burden should develop targeted measures to control PM2.5.

High sucrose intake exacerbates airway inflammation through pathogenic Th2 and Th17 response in ovalbumin (OVA)-induced acute allergic asthma in C57BL/6 mice

Asthma is an inflammatory disease characterized by chronic inflammation in lung tissues and excessive mucus production. High-fat diets have long been assumed to be a potential risk factor for asthma. However, to date, very few direct evidence indicating the involvement of high sucrose intake (HSI) in asthma progression exists. In this study, we investigate the effect of HSI on ovalbumin (OVA)-sensitized allergic asthma mice. We observed that HSI increased the expression of inflammatory genes (IL-1β, IL-6, TNF-α) in adipose tissues and led to reactive oxygen species generation in the liver and lung. In addition, HSI accelerated the TLR4/NF-κB signaling pathway leading to MMP9 activation, which promotes the chemokines and TGF-β secretion in the lungs of OVA-sensitized allergic asthma mice. More importantly, HSI significantly promoted the pathogenic Th2 and Th17 responses. The increase of IL-17A secretion by HSI increased the expression of chemokines (MCP-1, CXCL1, CXCL5, CXCL8). It resulted in eosinophil and mast cell infiltration in the lung and trachea. We also demonstrated that HSI increased mucus hypersecretion, which was validated by increased main mucin protein (MUC5AC) secreted in the lungs. Our findings suggest that HSI exacerbates the development of Th2/Th17-predominant asthma by upregulating the TLR4-mediated NF-κB pathway, leading to excessive MMP9 production.

Network pharmacology and experimental evidence: MAPK signaling pathway is involved in the anti-asthma roles of Perilla frutescens leaf

Perilla frutescens (PF) leaf is a traditional Chinese medicine and food with beneficial effects on allergic asthma. We sought to elucidate the active compounds, the targets, and underlying mechanisms of PF leaf in the treatment of allergic asthma by using experimental pharmacology and network pharmacology. An OVA-allergic asthma murine model was constructed to evaluate the effect of PF leaf on allergic asthma. And the network pharmacology and western blotting were performed to evaluate its underlying mechanisms in allergic asthma. PF leaf treatment significantly improved the lung function of OVA model mice and mitigated lung injury by significantly reducing of OVA-specific immunoglobulin E in serum, and interleukin 4, interleukin 5 and tumor necrosis factor alpha in the bronchoalveolar lavage fluid. 50 core targets were screened based on 8 compounds (determined by high performance liquid chromatography) through compound-target- disease network. Furthermore, MAPK signaling pathway was identified as the pathway mediated by PF leaf with the most potential against allergic asthma. And the WB results showed that PF leaf could down-regulate the expression of p-ERK, p-JNK and p-p38, which was highly consistent with the predicted targets and pathway network. In conclusion, this study provides the evidence to support the molecular mechanisms of PF leaf on the treatment of allergic asthma using network pharmacology and in vivo experiments.

Amphiregulin Exerts Proangiogenic Effects in Developing Murine Lungs

Interrupted lung angiogenesis is a hallmark of bronchopulmonary dysplasia (BPD); however, druggable targets that can rescue this phenotype remain elusive. Thus, our investigation focused on amphiregulin (Areg), a growth factor that mediates cellular proliferation, differentiation, migration, survival, and repair. While Areg promotes lung branching morphogenesis, its effect on endothelial cell (EC) homeostasis in developing lungs is understudied. Therefore, we hypothesized that Areg promotes the proangiogenic ability of the ECs in developing murine lungs exposed to hyperoxia. Lung tissues were harvested from neonatal mice exposed to normoxia or hyperoxia to determine Areg expression. Next, we performed genetic loss-of-function and pharmacological gain-of-function studies in normoxia- and hyperoxia-exposed fetal murine lung ECs. Hyperoxia increased Areg mRNA levels and Areg+ cells in whole lungs. While Areg expression was increased in lung ECs exposed to hyperoxia, the expression of its signaling receptor, epidermal growth factor receptor, was decreased, indicating that hyperoxia reduces Areg signaling in lung ECs. Areg deficiency potentiated hyperoxia-mediated anti-angiogenic effects. In contrast, Areg treatment increased extracellular signal-regulated kinase activation and exerted proangiogenic effects. In conclusion, Areg promotes EC tubule formation in developing murine lungs exposed to hyperoxia.

Progression of the PI3K/Akt signaling pathway in chronic obstructive pulmonary disease

Chronic Obstructive Pulmonary Disease (COPD) is a chronic respiratory disease characterized by a slow progression and caused by the inhalation of harmful particulate matter. Cigarette smoke and air pollutants are the primary contributing factors. Currently, the pathogenesis of COPD remains incompletely understood. The PI3K/Akt signaling pathway has recently emerged as a critical regulator of inflammation and oxidative stress response in COPD, playing a pivotal role in the disease's progression and treatment. This paper reviews the association between the PI3K/Akt pathway and COPD, examines effective PI3K/Akt inhibitors and novel anti-COPD agents, aiming to identify new therapeutic targets for clinical intervention in this disease.

Schwann cell-derived amphiregulin enhances nerve regeneration via supporting the proliferation and migration of Schwann cells and the elongation of axons

Peripheral nerves have limited regeneration ability following nerve injury. Applying growth factors with neurotrophic roles is beneficial for accelerating peripheral nerve regeneration. Here we show that after rat sciatic nerve injury, growth factor amphiregulin (AREG) is upregulated in Schwann cells of sciatic nerves. Elevated AREG stimulates the proliferation and migration of Schwann cells by activating ERK1/2 cascade. Schwann cell-secreted AREG further facilitates the outgrowth of neurites and the elongation of injured axons. Administration of AREG to injured sciatic nerves stimulates the proliferation of Schwann cells to replace lost cell population, encourages the migration of Schwann cells to form cell cords, and facilitates the regrowth of axons. Overall, our results identify AREG as an important neurotrophic factor and thus provide a promising therapeutic avenue towards peripheral nerve injury.

Effects of brake wear nanoparticles on the protection and repair functions of the airway epithelium

Long term exposure to particulate air pollution is known to increase respiratory morbidity and mortality. In urban areas with dense traffic most of these particles are generated by vehicles, via engine exhaust or wear processes. Non-exhaust particles come from wear processes such as those concerning brakes and their toxicity is little studied. To improve our understanding of the lung toxicity mechanisms of the nanometric fraction of brake wear nanoparticles (BWNPs), we studied whether these particles affect the barrier properties of the respiratory epithelium considering particle translocation, mucus production and repair efficiency. The Calu-3 cell line grown in two-compartment chambers was used to mimic the bronchial epithelial barrier. BWNPs detected by single-particle ICP-MS were shown to cross the epithelial tissue in small amounts without affecting the barrier integrity properties, because the permeability to Lucifer yellow was not increased and there was no cytotoxicity as assessed by the release of lactate-dehydrogenase. The interaction of BWNPs with the barrier did not induce a pro-inflammatory response, but increased the expression and production of MU5AC, a mucin, by a mechanism involving the epidermal growth factor receptor pathway. During a wound healing assay, BWNP-loaded cells exhibited the same ability to migrate, but those at the edge of the wound showed higher 5-ethynyl-2'-deoxyuridine incorporation, suggesting a higher proliferation rate. Altogether these results showed that BW. NPs do not exert overt cytotoxicity and inflammation but can translocate through the epithelial barrier in small amounts and increase mucus production, a key feature of acute inflammatory and chronic obstructive pulmonary diseases. Their loading in epithelial cells may impair the repair process through increased proliferation.

Perturbation of arachidonic acid and glycerolipid metabolism promoted particulate matter-induced inflammatory responses in human bronchial epithelial cells

Particulate matter (PM) has become the main risk factor for public health, being linked with an increased risk of respiratory diseases. However, the potential mechanisms underlying PM-induced lung injury have not been well elucidated. In this study, we systematically integrated the metabolomics, lipidomics, and transcriptomics data obtained from the human bronchial epithelial cells (HBECs) exposed to PM to reveal metabolic disorders in PM-induced lung injury. We identified 170 differentially expressed metabolites (82 upregulated and 88 downregulated metabolites), 218 differentially expressed lipid metabolites (125 upregulated and 93 downregulated lipid metabolites), and 1417 differentially expressed genes (643 upregulated and 774 downregulated genes). Seven key metabolites (prostaglandin E2, inosinic acid, L-arginine, L-citrulline, L-leucine, adenosine, and adenosine monophosphate), and two main lipid subclasses (triglyceride and phosphatidylcholine) were identified in PM-exposed HBECs. The amino acid metabolism, lipid metabolism, and carbohydrate metabolism were the significantly enriched pathways of identified differentially expressed genes. Then, conjoint analysis of these three omics data and further qRT-PCR validation showed that arachidonic acid metabolism, glycerolipid metabolism, and glutathione metabolism were the key metabolic pathways in PM-exposed HBECs. The knockout of AKR1C3 in arachidonic acid metabolism or GPAT3 in glycerolipid metabolism could significantly inhibit PM-induced inflammatory responses in HBECs. These results revealed the potential metabolic pathways in PM-exposed HBECs and provided a new target to protect from PM-induced airway damage.

Effects of Pendrin Protein in Nasal Epithelial Cells on Mucin Production in the Context of Type 2 Inflammation

Background: Chronic rhinosinusitis (CRS) is a heterogeneous disease. The pathogenesis of chronic sinusitis is still unclear; however, the nasal cavity and paranasal sinuses are commonly affected by type 2 inflammation, which is caused by Th2 cytokines such as interleukin (IL)-5, IL-4, and IL-13. Previous studies have shown that pendrin promotes local infiltration of neutrophils through the production of human neutrophil elastase (HNE), which is essential for the secretion of mucin 5AC (MUC5AC) in chronic inflammatory diseases of the lower respiratory tract. This study investigated pendrin expression and its relationship to mucin in type 2 inflammation. Methods: A total of 40 patients (10 CRS patients with nasal polyps,10 CRS patients without nasal polyps, and 20 nasal septum deviation patients) were included in this study and were divided into the CRS group and the NC group. A normal nasal mucosa tissue culture model was established in vitro. IL-13 was used to stimulate primary cultures of human nasal epithelial cells (HNECs). Western blot (WB), enzyme-linked immunosorbent assay (ELISA), and quantitative real-time polymerase chain reaction (qRT-PCR) were used to detect the expression of pendrin, MUC5AC, and MUC5B. After transfecting HNECs with siRNA pendrin or negative control (NC), EGF receptor (EGFR), HNE, MUC5AC, and MUC5B expression were analyzed using qRT-PCR, WB, or ELISA in terms of their relationships with pendrin. Pendrin expression in the tissue was also analyzed. Results: After IL-13 stimulation, pendrin, MUC5AC, and MUC5B expression levels were upregulated; the optimal concentration of IL-13 was 50 ng/mL. The expression levels of HNE, EGFR, MUC5AC, and MUC5B were downregulated after transfection with siRNA pendrin-1650. Pendrin expression in the NC group was lower than in the CRS group. Conclusion: IL-13 is implicated in the inflammation of nasal mucosa, and pendrin is closely related to the excessive secretion of mucin. The expression of mucin is downregulated after transfection with siRNA pendrin. There is a positive relationship between pendrin and EFGR/HNE. Moreover, pendrin plays an important role in type 2 inflammation.

The Road to Malignant Cell Transformation after Particulate Matter Exposure: From Oxidative Stress to Genotoxicity

In cells, oxidative stress is an imbalance between the production/accumulation of oxidants and the ability of the antioxidant system to detoxify these reactive products. Reactive oxygen species (ROS), cause multiple cellular damages through their interaction with biomolecules such as lipids, proteins, and DNA. Genotoxic damage caused by oxidative stress has become relevant since it can lead to mutation and play a central role in malignant transformation. The evidence describes chronic oxidative stress as an important factor implicated in all stages of the multistep carcinogenic process: initiation, promotion, and progression. In recent years, ambient air pollution by particulate matter (PM) has been cataloged as a cancer risk factor, increasing the incidence of different types of tumors. Epidemiological and toxicological evidence shows how PM-induced oxidative stress could mediate multiple events oriented to carcinogenesis, such as proliferative signaling, evasion of growth suppressors, resistance to cell death, induction of angiogenesis, and activation of invasion/metastasis pathways. In this review, we summarize the findings regarding the involvement of oxidative and genotoxic mechanisms generated by PM in malignant cell transformation. We also discuss the importance of new approaches oriented to studying the development of tumors associated with PM with more accuracy, pursuing the goal of weighing the impact of oxidative stress and genotoxicity as one of the main mechanisms associated with its carcinogenic potential.

The Effects and Pathogenesis of PM2.5 and Its Components on Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD), a heterogeneous disease, is the leading cause of death worldwide. In recent years, air pollution, especially particulate matter (PM), has been widely studied as a contributing factor to COPD. As an essential component of PM, PM2.5 is associated with COPD prevalence, morbidity, and acute exacerbations. However, the specific pathogenic mechanisms were still unclear and deserve further research. The diversity and complexity of PM2.5 components make it challenging to get its accurate effects and mechanisms for COPD. It has been determined that the most toxic PM2.5 components are metals, polycyclic aromatic hydrocarbons (PAHs), carbonaceous particles (CPs), and other organic compounds. PM2.5-induced cytokine release and oxidative stress are the main mechanisms reported leading to COPD. Nonnegligibly, the microorganism in PM 2.5 may directly cause mononuclear inflammation or break the microorganism balance contributing to the development and exacerbation of COPD. This review focuses on the pathophysiology and consequences of PM2.5 and its components on COPD.

Mesenchymal stem cell-derived extracellular vesicles protect retina in a mouse model of retinitis pigmentosa by anti-inflammation through miR-146a-Nr4a3 axis

Background

Retinitis pigmentosa is a rod-cone degenerative disease that induces irreversible vision loss. This study probed the protective capacity of mesenchymal stem cell-derived small EVs (MSC-EVs) on the retinas of rd10 mice and the underlying mechanism.

Methods

MSC-EVs were injected into the vitreous of rd10 mice at postnatal day 14 and P21; morphology and function were examined at P28. The mechanism of action was explored by using co-culture of photoreceptor cell line 661 W and microglia cell line BV2.

Results

Treatment with MSC-EVs increased the survival of photoreceptors and preserved their structure. Visual function, as reflected by optomotor and electroretinogram responses, was significantly enhanced in MSC-EVs-treated rd10 mice. Mechanistically, staining for Iba1, GFAP, F4/80, CD68 and CD206 showed that MSC-EVs suppressed the activation of microglial, Müller glial and macrophages. Furthermore, western blotting showed that the treatment inhibited the NF-κB pathway. RNA-seq and qPCR showed that MSC-EVs upregulated anti-inflammatory cytokines while downregulating pro-inflammatory cytokines. MSC-EVs application in vitro decreased the number of TUNEL-positive 661 W cells co-cultured with LPS-stimulated BV2, with similar impact on the cytokine expression as in vivo study. Genetic screening predicted miR-146a to be the downstream target of MSC-EVs, which was detected in MSC-EVs and upregulated in co-cultured 661 W cells and BV2 cells after MSC-EVs treatment. Upregulation of miR-146a by using its mimic decreased the expression of the transcription factor Nr4a3, and its downregulation inhibition promoted Nr4a3 expression in both 661 W and BV2 cells. Nr4a3 was further identified as the target gene of miR-146a by dual-luciferase assay. Furthermore, overexpressing miR-146a significantly decreased the expression of LPS-induced pro-inflammatory cytokines in BV2 cells.

Conclusions

MSC-EVs delays retinal degeneration in rd10 mice mainly by its anti-inflammatory effect via the miR-146a-Nr4a3axis. Hence, MSC-EVs may be used in the treatment of neurodegenerative diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03100-x.

Comprehensive analysis of transcriptome-wide m6A methylome in the lung tissues of mice with acute particulate matter exposure

Particulate matter (PM) exposure is identified as a critical risk factor for chronic airway diseases, but the biological mechanism of PM-induced lung damage was not fully elucidated. The m⁶A methylation, as the main member of epigenetic modifications, has been found to play an important role in different pulmonary diseases, but its regulatory effect on PM-induced lung damage remains unknown. This study firstly used the methylated RNA immunoprecipitation sequencing (MeRIP-seq) to reveal the m⁶A methylome profiles in the lung tissues of mice with acute PM exposure. Compared with the normal control, a total of 2210 differentially hypermethylated m⁶A peaks within 1879 genes and 1278 differentially hypomethylated m⁶A peaks within 1153 genes were identified in the PM-exposed group. Conjoint analysis of MeRIP-seq and high-throughput sequencing for RNA (RNA-seq) data predicated several potential pathways including MAPK signaling pathway, cell senescence, and cell cycle. Four m⁶A-modified differentially expressed genes (IL-1a, IL-1b, ADAM-8, and HMOX-1) were selected for validation using MeRIP-qPCR. Furthermore, the m⁶A-modified IL-1a promoted PM-induced inflammation via regulating MAPK signaling pathway. These results provide a new insight into the biological mechanism of PM-induced lung damage, and help us to develop new methods to prevent and treat PM-induced adverse health effects.

Particulate matter in COPD pathogenesis: an overview

Chronic obstructive pulmonary disease (COPD) is a progressive lung disorder with substantial patient burden and leading cause of death globally. Cigarette smoke remains to be the most recognised causative factor behind COPD pathogenesis. Given the alarming increase in prevalence of COPD amongst non-smokers in recent past, a potential role of air pollution particularly particulate matter (PM) in COPD development has gained much attention of the scientists. Indeed, several epidemiological studies indicate strong correlation between airborne PM and COPD incidence/exacerbations. PM-induced oxidative stress seems to be the major player in orchestrating COPD inflammatory cycle but the exact molecular mechanism(s) behind such a process are still poorly understood. This may be due to the complexity of multiple molecular pathways involved. Oxidative stress-linked mitochondrial dysfunction and autophagy have also gained importance and have been the focus of recent studies regarding COPD pathogenesis. Accordingly, the present review is aimed at understanding the key molecular players behind PM-mediated COPD pathogenesis through analysis of various experimental studies supported by epidemiological data to identify relevant preventive/therapeutic targets in the area.

Establishment of Repeated In Vitro Exposure System for Evaluating Pulmonary Toxicity of Representative Criteria Air Pollutants Using Advanced Bronchial Mucosa Models

There is mounting evidence that shows the association between chronic exposure to air pollutants (particulate matter and gaseous) and onset of various respiratory impairments. However, the corresponding toxicological mechanisms of mixed exposure are poorly understood. Therefore, in this study, we aimed to establish a repeated exposure setting for evaluating the pulmonary toxicological effects of diesel exhaust particles (DEP), nitrogen dioxide (NO2), and sulfur dioxide (SO2) as representative criterial air pollutants. Single, combined (DEP with NO2 and SO2), and repeated exposures were performed using physiologically relevant human bronchial mucosa models developed at the air−liquid interface (bro-ALI). The bro-ALI models were generated using human primary bronchial epithelial cells (3−4 donors; 2 replicates per donor). The exposure regime included the following: 1. DEP (12.5 µg/cm2; 3 min/day, 3 days); 2. low gaseous (NO2: 0.1 ppm + SO2: 0.2 ppm); (30 min/day, 3 days); 3. high gaseous (NO2: 0.2 ppm + SO2: 0.4 ppm) (30 min/day, 3 days); and 4. single combined (DEP + low gaseous for 1 day). The markers for pro-inflammatory (IL8, IL6, NFKB, TNF), oxidative stress (HMOX1, GSTA1, SOD3,) and tissue injury/repair (MMP9, TIMP1) responses were assessed at transcriptional and/ or secreted protein levels following exposure. The corresponding sham-exposed samples under identical conditions served as the control. A non-parametric statistical analysis was performed and p < 0.05 was considered as significant. Repeated exposure to DEP and single combined (DEP + low gaseous) exposure showed significant alteration in the pro-inflammatory, oxidative stress and tissue injury responses compared to repeated exposures to gaseous air pollutants. The study demonstrates that it is feasible to predict the long-term effects of air pollutants using the above explained exposure system.

Edaravone Attenuated Particulate Matter-Induced Lung Inflammation by Inhibiting ROS-NF-κB Signaling Pathway

Background

Particulate matter (PM) exposure is related to mitochondria dysfunction and airway inflammation. Antioxidant drug edaravone (EDA) is reported to improve the occurrence and development of oxidative stress-related diseases. At present, there is no data on whether EDA can alleviate lung inflammation caused by PM.

Methods

The anti-inflammatory effects of EDA were investigated in urban PM-induced human bronchial epithelial cells (HBECs) and C57/BL6J mouse models. In vitro, its effects on the production of intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and inflammatory cytokines were assessed by DCFH-DA staining, JC-1 assay, and real-time PCR, respectively. In vivo, the oxidant stress in lung tissues was assessed by dihydroethidium (DHE) staining and malondialdehyde (MDA) activity, and inflammatory cytokines in bronchoalveolar lavage fluid (BALF) were assessed by ELISA, respectively. Furthermore, the potential signaling pathways were studied by siRNA transfection and western blot.

Results

PM increased the expression of inflammatory cytokines and protein, including IL-6, IL-1α, IL-1β, and COX-2, while these alternations were significantly alleviated following EDA treatment in a dose-dependent manner. EDA treatment also alleviated the inflammatory responses in lung tissues of PM-exposed mice. We further showed mitochondrial dysfunction in PM-exposed HBECs and mice, which were reversed by EDA treatment. Moreover, the phosphorylation of NF-κB p65 in PM-exposed HBECs and mice was weakened by EDA. Transfection with NF-κB p65 siRNA further inhibited PM-induced inflammation in HBECs.

Conclusion

We demonstrated that EDA treatment had a protective role in PM-induced lung inflammation through maintaining mitochondrial balance and regulating the ROS-NF-κB p65 signaling pathway. This provided a new therapeutic method for PM-induced lung inflammation in the future.

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

Environmental Exposures and Lung Aging: Molecular Mechanisms and Implications for Improving Respiratory Health

PURPOSE OF REVIEW

Inhaled environmental exposures cause over 12 million deaths per year worldwide. Despite localized efforts to reduce environmental exposures, tobacco smoking and air pollution remain the urgent public health challenges that are contributing to the growing prevalence of respiratory diseases. The purpose of this review is to describe the mechanisms through which inhaled environmental exposures accelerate lung aging and cause overt lung disease.

RECENT FINDINGS

Environmental exposures related to fossil fuel and tobacco combustion and occupational exposures related to silica and coal mining generate oxidative stress and inflammation in the lungs. Sustained oxidative stress causes DNA damage, epigenetic instability, mitochondrial dysfunction, and cell cycle arrest in key progenitor cells in the lung. As a result, critical repair mechanisms are impaired, leading to premature destruction of the lung parenchyma. Inhaled environmental exposures accelerate lung aging by injuring the lungs and damaging the cells responsible for wound healing. Interventions that minimize exposure to noxious antigens are critical to improve lung health, and novel research is required to expand our knowledge of therapies that may slow or prevent premature lung aging.

Effects of ozone and particulate matter on airway epithelial barrier structure and function: a review of in vitro and in vivo studies

The airway epithelium represents a crucial line of defense against the spread of inhaled pathogens. As the epithelium is the first part of the body to be exposed to the inhaled environment, it must act as both a barrier to and sentinel against any inhaled agents. Despite its vital role in limiting the spread of inhaled pathogens, the airway epithelium is also regularly exposed to air pollutants which disrupt its normal function. Here we review the current understanding of the structure and composition of the airway epithelial barrier, as well as the impact of inhaled pollutants, including the reactive gas ozone and particulate matter, on epithelial function. We discuss the current in vitro, rodent model, and human exposure findings surrounding the impact of various inhaled pollutants on epithelial barrier function, mucus production, and mucociliary clearance. Detailed information on how inhaled pollutants impact epithelial structure and function will further our understanding of the adverse health effects of air pollution exposure.

Resveratrol inhibits MUC5AC expression by regulating SPDEF in lung cancer cells

BACKGROUND

MUC5AC was recently identified to play important roles in the proliferation and metastasis of malignant mucinous lung tumor cells. Resveratrol (Res), a natural compound with anticancer effects in lung cancer cells, has been reported to inhibit mucin production in airway epithelial cells. This study aimed to investigate the inhibitory effect of Res on MUC5AC expression in lung mucinous adenocarcinoma cells and the potential mechanisms.

METHODS

Mucus-producing A549 human lung carcinoma cells were used to test the effects of Res on SPDEF and MUC5AC expression. Gene and protein expression was assessed by real-time quantitative PCR (qPCR), immunofluorescence and western blotting assays. SPDEF lentivirus was used to upregulate SPDEF expression levels in mucus-producing A549 human lung carcinoma cells. Cell proliferation was assessed by Cell Counting Kit-8 (CCK-8) assay.

RESULTS

Res decreased MUC5AC expression in an SPDEF-dependent manner in mucus-producing A549 human lung carcinoma cells, and this change was accompanied by decreased ERK expression and AKT pathway activation. Moreover, SPDEF was found to be overexpressed in lung adenocarcinoma (LUAD), especially in mucinous adenocarcinoma. In-vitro functional assays showed that overexpression of SPDEF reduced the chemosensitivity of A549 cells to cisplatin (DDP). In addition, Res treatment increased A549 cell chemosensitivity to DDP by inhibiting the SPDEF-MUC5AC axis.

CONCLUSION

Our results indicate that the SPDEF-MUC5AC axis is associated with DDP sensitivity, and that Res decreases SPDEF and MUC5AC expression by inhibiting ERK and AKT signaling in A549 cells, which provides a potential pharmacotherapy for the prevention and therapeutic management of mucinous adenocarcinoma.

TPD7 inhibits the non-small cell lung cancer HCC827 cell growth by regulating EGFR signalling pathway

Non-small cell lung cancer (NSCLC) accounts for 85% of lung cancer cases, and is characterized by more insensitivity to chemotherapy and poor prognosis. Epidermal growth factor receptor (EGFR) has been confirmed as a tumorigenic driving factor of NSCLC. Taspine has been proved effective in the inhibition of malignant tumours. Here, we found TPD7, a novel taspine derivative, exerted most inhibitory effect on EGFR-dependent HCC827 cells and investigated the underling mechanism. In addition, TPD7 could block cell cycle at G0/G1 phase of HCC827 cells by regulating the expression of cyclin D1 and cyclin E. Furthermore, TPD7 induced HCC827 cell apoptosis by regulating the expression of BCL-2 family proteins. Further study revealed that TPD7 could down-regulate the phosphorylation of EGFR and downstream members. TPD7 might present a potential EGFR inhibitor in the treatment of NSCLC.

Aberrant Methylation of Aging-Related Genes in Asthma

Background: Asthma is a complex pulmonary inflammatory disease which is common among older adults. Aging-related alterations have also been found in structural cells and immune cells of asthma patients. Nonetheless, the underlying mechanism by which differenced aging-related gene contributes to asthma pathology remains unclear. Of note, DNA methylation (DNAm) has been proven to play a critical mechanism for age-related gene expression changes. However, the methylation changes of aging-related genes in asthma patients are still obscure.

Methods: First, changes in DNAm and gene expression were detected with multiple targeted bisulfite enrichment sequencing (MethTarget) and qPCR in peripheral blood of 51 healthy controls (HCs) and 55 asthmatic patients. Second, the correlation between the DNAm levels of specific altered CpG sites and the pulmonary function indicators of asthma patients was evaluated. Last, the receiver operator characteristic (ROC) curve and principal component analysis (PCA) were used to identify the feasibility of the candidate CpG sites as biomarkers for asthma.

Results: Compared with HCs, there was a differential mRNA expression for nine aging-related genes in peripheral blood of asthma patients. Besides, the methylation levels of the nine aging-related genes were also altered in asthma patients, and a total of 68 CpG sites were associated with the severity of asthma. Notably, 9 of the 68 CpG sites were significantly associated with pulmonary function parameters. Moreover, ROC curve and PCA analysis showed that the candidate differential methylation sites (DMSs) can be used as potential biomarkers for asthma.

Conclusions: In summary, this study confirmed the differentially expressed mRNA and aberrant DNAm level of aging-related genes in asthma patients. DMSs are associated with the clinical evaluation indicators of asthma, which indicate the involvement of aging-related genes in the pathogenesis of asthma and provide some new possible biomarkers for asthma.

sRAGE Inhibits the Mucus Hypersecretion in a Mouse Model with Neutrophilic Asthma

Background: Neutrophilic asthma (NA) may result in irreversible airflow limitations. Soluble advanced glycosylation receptor (sRAGE) has been shown to be associated with neutrophilic airway inflammation. However, the association between sRAGE and mucus hypersecretion in NA remains unknown. This study aims to assess the function of sRAGE on mucus hypersecretion.Methods: A NA mouse model was established and treated with adeno-associated virus 9 (AAV9)-sRAGE and inhibitors. Collagen deposition and goblet cell hyperplasia in the lungs were evaluated by periodic acid-Schiff (PAS) and Masson staining. sRAGE and mucin levels in bronchoalveolar lavage fluid were measured by ELISA. Pathway molecule expression levels were determined by RT-qPCR and western blotting.Results: The results showed that the NA mouse model exhibited airway mucus hypersecretion. Mice can be effectively transfected by AAV9-sRAGE via tail-vein injection and intranasal drip. AAV9-sRAGE increased the sRAGE levels but it inhibited the collagen deposition, the PAS score, as well as the expression of MUC5AC and MUC5B. Inhibitors of high-mobility group protein 1 (HMGB1), receptor for advanced glycation end product (RAGE) and phosphatidylinositol 3-kinase (PI3K) suppressed the MUC5AC levels in NA mice as well as in cultured HMGB1-induced human bronchial epithelial cells. Furthermore, the phospho- extracellular signal-regulated kinase (ERK) protein in NA was increased while the sRAGE intervention inhibited this elevation.Conclusions: These results suggest that sRAGE may be a potential target for the treatment of mucus hypersecretion in NA.

The transition of M-CSF-derived human macrophages to a growth-promoting phenotype

Stimulated macrophages are potent producers of inflammatory mediators. This activity is highly regulated, in part, by resolving molecules to prevent tissue damage. In this study, we demonstrate that inflammation induced by Toll-like receptor stimulation is followed by the upregulation of receptors for adenosine (Ado) and prostaglandin E2 (PGE2), which help terminate macrophage activation and initiate tissue remodeling and angiogenesis. Macrophages can be hematopoietically derived from monocytes in response to 2 growth factors: macrophage colony-stimulating factor (M-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF). We examine how exposure to either of these differentiation factors shapes the macrophage response to resolving molecules. We analyzed the transcriptomes of human monocyte-derived macrophages stimulated in the presence of Ado or PGE2 and demonstrated that, in macrophages differentiated in M-CSF, Ado and PGE2 induce a shared transcriptional program involving the downregulation of inflammatory mediators and the upregulation of growth factors. In contrast, macrophages generated in GM-CSF fail to convert to a growth-promoting phenotype, which we attribute to the suppression of receptors for Ado and PGE2 and lower production of these endogenous regulators. These observations indicate that M-CSF macrophages are better prepared to transition to a program of tissue repair, whereas GM-CSF macrophages undergo more profound activation. We implicate the differential sensitivity to pro-resolving mediators as a contributor to these divergent phenotypes. This research highlights a number of molecular targets that can be exploited to regulate the strength and duration of macrophage activation.

Sargassum horneri extract containing mojabanchromanol attenuates the particulate matter exacerbated allergic asthma through reduction of Th2 and Th17 response in mice

Airborne particulate matter (PM) has become a serious health issue causing pulmonary diseases such as asthma. Due to the side effects and non-specificity of conventional drugs, there is a need to develop natural-product-based alternative treatments. Sargassum horneri is a brown alga shown to have anti-oxidant, anti-inflammatory, and anti-allergic effects. Thus, we sought to determine whether ethanol extract of Sargassum horneri (SHE) mitigates the effect of PM exposure on asthma development. To establish a mouse model of asthma, BALB/c mice were sensitized with ovalbumin (OVA, 10 μg) and challenged with PM (5 mg/m3) for 7 days consecutively. SHE (200, 400 mg/kg), Prednisone (5 mg/kg), or PBS was daily administrated orally before PM exposure. SHE mitigated PM exacerbated dendritic cell activation. More importantly, SHE restrained Th2 polarization by attenuating transcription factors GATA3 and STAT5, which further mitigated the expression of Th2 cytokines interleukin (IL)-4, IL-5, and IL-13 in the lung homogenates of PM-exacerbated asthmatic mice. SHE further attenuated PM-exacerbated eosinophil infiltration in the lung, trachea, and BALF. In addition, SHE markedly mitigated the activation of mast cells and the IgE level in serum. Concomitantly, SHE further restrained the Th17 cell response in PM-exposed allergic mice through attenuating expression of transcription factors RORγT, STAT3 and expression of relevant effector cytokines IL-17a. This resulted in mitigated neutrophil infiltration in the lung. Taken together, SHE significantly suppressed PM-exacerbated hypersecretion of mucus in asthmatic mice. These results suggest that SHE has therapeutic potential for treating PM-exacerbated allergic asthma through concomitantly inhibiting Th2/Th17 responses.

Prenatal smoke exposure dysregulates lung epithelial cell differentiation in mouse offspring: role for AREG-induced EGFR signaling

Prenatal smoke exposure is a risk factor for impaired lung development in children. Recent studies have indicated that amphiregulin (AREG), which is a ligand of the epidermal growth factor receptor (EGFR), has a regulatory role in airway epithelial cell differentiation. In this study, we investigated the effect of prenatal smoke exposure on lung epithelial cell differentiation and linked this with AREG-EGFR signaling in 1-day-old mouse offspring. Bronchial and alveolar epithelial cell differentiations were assessed by immunohistochemistry. Areg, epidermal growth factor (Egf), and mRNA expressions of specific markers for bronchial and alveolar epithelial cells were assessed by RT-qPCR. The results in neonatal lungs were validated in an AREG-treated three-dimensional mouse lung organoid model. We found that prenatal smoke exposure reduced the number of ciliated cells and the expression of the cilia-related transcription factor Foxj1, whereas it resulted in higher expression of mucus-related transcription factors Spdef and Foxm1 in the lung. Moreover, prenatally smoke-exposed offspring had higher numbers of alveolar epithelial type II cells (AECII) and lower expression of the AECI-related Pdpn and Gramd2 markers. This was accompanied by higher expression of Areg and lower expression of Egf in prenatally smoke-exposed offspring. In bronchial organoids, AREG treatment resulted in fewer ciliated cells and more basal cells when compared with non-treated bronchiolar organoids. In alveolar organoids, AREG treatment led to more AECII cells than non-treated AECII cells. Taken together, the observed impaired bronchial and alveolar cell development in prenatally smoke-exposed neonatal offspring may be induced by increased AREG-EGFR signaling.

Fine particulate matter reduces the pluripotency and proliferation of human embryonic stem cells through ROS induced AKT and ERK signaling pathway

Epidemiological investigations have found that air fine particulate matter (PM) exposure not only causes respiratory and cardiovascular diseases in adults and children, but also affects embryonic development during pregnancy, leading to poor pregnancy outcomes. However, its exact molecular mechanism is still unclear. In this study, human embryonic stem cells (hESCs) were treated with PM at different concentrations then the morphology and proliferation capacity were measured. The mRNA and protein expression of NANOG and OCT4 were detected using quantitative PCR, immunofluorescence, western blotting, and flow cytometry. Reactive oxygen species (ROS) generation and AKT/ERK activation were also measured. Meanwhile, changes in ROS, the expression of NANOG, OCT4, and the AKT/ERK pathways were measured in the hESCs with or without pretreatment of ROS scavenger N-acetylcysteine (NAC) prior to PM exposure. After PM exposure, the proliferation capacity and expression of OCT4 and NANOG at the mRNA and protein levels were downregulated. The ROS level in the hESCs increased after PM exposure, but this increase in ROS was attenuated by pretreatment with NAC. Further analysis showed that the levels of phosphorylated AKT and ERK increased after PM exposure. After pretreatment with NAC, the phosphorylation levels of AKT and ERK, which are crucial for regulating the proliferation, pluripotency, and differentiation of hESC, were significantly attenuated compared with the non-NAC pretreated exposure group. These results suggest that PM exposure may reduce the proliferation and pluripotency of hESC through ROS-mediated AKT/ERK pathways, thereby affecting the long-term development of embryos.

Effective-component compatibility of Bufei Yishen formula II inhibits mucus hypersecretion of chronic obstructive pulmonary disease rats by regulating EGFR/PI3K/mTOR signaling

ETHNOPHARMACOLOGICAL RELEVANCE

The effective-component compatibility of Bufei Yishen formula I (ECC-BYF I), a combination of 10 compounds, including total ginsenosides, astragaloside IV, icariin, and paeonol, etc., is derived from Bufei Yishen formula (BYF). The efficacy and safety of ECC-BYF I is equal to BYF. However, the composition of ECC-BYF I needs to be further optimized. Based on the beneficial effects of BYF and ECC-BYF I on chronic obstructive pulmonary disease (COPD), this study aimed to optimize the composition of ECC-BYF I and to explore the effects and mechanisms of optimized ECC-BYF I (ECC-BYF II) on mucus hypersecretion in COPD rats.

MATERIALS AND METHODS

ECC-BYF I was initially optimized to six groups: optimized ECC-BYF I (OECC-BYF I)-A~F. Based on a COPD rat model, the effects of OECC-BYF I-A~F on COPD rats were evaluated. R-value comprehensive evaluation was used to evaluate the optimal formula, which was named ECC-BYF II. The changes in goblet cells and expression of mucins and the mRNA and proteins involved in the epidermal growth factor receptor/phosphoinositide-3-kinase/mammalian target of rapamycin (EGFR/PI3K/mTOR) pathway were evaluated to explore the effects and mechanisms of ECC-BYF II on mucus hypersecretion.

RESULTS

ECC-BYF I and its six optimized groups, OECC-BYF I-A~F, had beneficial effects on COPD rats in improving pulmonary function and lung tissue pathology, reducing inflammation and oxidative stress, and improving the protease/anti-protease imbalance and collagen deposition. R-value comprehensive evaluation found that OECC-BYF I-E (paeonol, icariin, nobiletin, total ginsenoside, astragaloside IV) was the optimal formula for improving the comprehensive effects (lung function: V_T, MV, PEF, EF50, FVC, FEV 0.1, FEV 0.1/FVC; histological changes: MLI, MAN; IL-1β, IL-6, TNF-α, MMP-9, TIMP-1, T-AOC, LPO, MUC5AC, Collagen I and Collagen III). OECC-BYF I-E was named ECC-BYF II. Importantly, the effect of ECC-BYF II showed no significant difference from BYF and ECC-BYF I. ECC-BYF II inhibited mucus hypersecretion in COPD rats, which manifested as reducing the expression of MUC5AC and MUC5B and the hyperplasia rate of goblet cells. The mRNA and protein expression levels of EGFR, PI3K, Akt, and mTOR were increased in COPD rats and were obviously downregulated after ECC-BYF II administration.

CONCLUSION

ECC-BYF II, which consists of paeonol, icariin, nobiletin, total ginsenoside and astragaloside IV, has beneficial effects equivalent to BYF and ECC-BYF I on COPD rats. ECC-BYF II significantly inhibited mucus hypersecretion, which may be related to the regulation of the EGFR/PI3K/mTOR pathway.

A SNP in the 3'UTR of the porcine IGF-1 gene interacts with miR-new14 to affect IGF-1 expression, proliferation and apoptosis of PK-15 cells

The kidney of miniature pigs has been considered the most likely potential kidney source for patients needing kidney transplantation. Insulin-like growth factor 1 (IGF-1) is involved in regulating the growth of miniature pigs and inducing growth of kidneys. There are evidences showing that the SNPs in the 3'UTR of a gene may affect the gene expression by affecting the binding to a miRNA target site. In this study, one SNP (rs34142920) was screened in the IGF-1 3'UTR between 2 different body types of porcine breeds, Bama Xiang (BX) pigs, a miniature pig breed, and Large White (LW) pigs by sequencing. The secondary structure of the IGF-1 3'UTR mRNA containing the SNP in BX pigs is different from that of LW pigs. We then verified that there was a porcine miRNA (miR-new14) binding to this SNP in the 3'UTR of IGF-1 via cotransfecting the 3'UTR from the 2 breeds and miR-new14. We further found that the SNP downregulated mRNA and protein levels of IGF-1 by affecting the binding of miR-new14. To understand the function of miR-new14 in porcine kidney (PK-15) cells and its mechanism, cell proliferation and cell apoptosis assays were employed and results showed that proliferation viability of PK-15 cells was weakened and the apoptotic percentage of PK-15 cells was higher in the miR-new14 group. Porcine miRNA reduced the mRNA expression of AKT/ERK and protein levels of p-AKT/p-ERK. These results suggested that the expression of IGF-1 is influenced by this SNP and miR-new14 and that miR-new14 may suppress cell proliferation and promote cell apoptosis in PK-15 cells through regulating AKT and ERK signaling pathways, in which IGF-1 is involved.

MiR-29b-3p promotes particulate matter-induced inflammatory responses by regulating the C1QTNF6/AMPK pathway

Inflammatory responses are considered to be the critical mechanism underlying particulate matter (PM)-induced development and exacerbation of chronic respiratory diseases. MiR-29b-3p has been found to participate in various biological processes, but its role in PM-induced inflammatory responses was previously unknown. Here, we constructed a miRNA PCR array to find that miR-29b-3p was the most highly expressed in human bronchial epithelial cells (HBECs) exposed to PM. MiR-29b-3p promoted PM-induced pro-inflammatory cytokines (IL-1β, IL-6, and IL-8) expression via inhibiting the AMPK signaling pathway in HBECs. RNA sequencing and luciferase reporter assay identified that miR-29b-3p targeted complement C1q tumor necrosis factor-related protein 6 (C1QTNF6), a protein that protected from PM-induced inflammatory responses via activating the AMPK signaling pathway. In vivo, miR-29b-3p antagomirs delivered via the tail vein prior to PM exposure significantly counteracted PM-induced miR-29b-3p upregulation and C1QTNF6 downregulation in lung tissues. Furthermore, miR-29b-3p inhibition alleviated inflammatory cells infiltration and pro-inflammatory cytokines secretion in the lung of PM-exposed mice. These findings firstly revealed that miR-29b-3p acted as a novel modulator of PM-induced inflammatory responses by targeting the C1QTNF6/AMPK signaling pathway, which contributes to a better understanding of the biological mechanisms underlying adverse PM-induced respiratory health effects.

The Role and Potential Pathogenic Mechanism of Particulate Matter in Childhood Asthma: A Review and Perspective

Asthma, the most common chronic respiratory disease in children, affects numerous people worldwide. Accumulating evidence suggests that exposure to high levels of particulate matter (PM), either acutely or chronically, is associated with the exacerbation and incidence of pediatric asthma. However, the detailed pathogenic mechanisms by which PM contributes to the incidence of asthma remain largely unknown. In this short review, we summarize studies of relationships between PM and pediatric asthma and recent advances on the fundamental mechanisms of PM-related asthma, with emphases on cell death regulation and immune system responses. We further discuss the inadequacy of current studies and give a perspective on the prevention strategies for pediatric asthma.

Docosahexaenoic Acid Serving As Sensitizing Agents And Gefitinib Resistance Revertants In EGFR Targeting Treatment

Objective

Due to the resistance of cancer cells, chemotherapy has been severely restricted. Docosahexaenoic acid (DHA) has been broadly identified as the chemo-sensitizing agent and revertant of multidrug resistance owing to its pleiotropic characteristics; however, it has not been well interpreted. The purpose of this research was to identify the anticancer role of DHA and its combination with the chemotherapeutic agent Gefitinib in non-small cell lung cancer (NSCLC).

Methods

Human chemo-sensitive NSCLC PC-9 cells and the Gefitinib-resistant counterpart PC-9/GR cells were adopted to assess the effects of the integrated DHA and Gefitinib treatments in vitro and vivo, for which the combination index (CI), apoptosis rate and the epithelial growth factor receptor (EGFR) pathway were analyzed.

Results

Comparing with the control cells, the DHA-treated PC-9/GR cells triggered the increase of drug absorption and sensitivity, suggesting that the sensitivity of chemotherapeutic drug could be induced by DHA. Moreover, the elevation of phosphorylation levels of EGFR and the downstream extracellular signal-regulated kinase (ERK) in the cellular lysates were induced by the DHA+Gefitinib treatment. Additionally, the long-term Gefitinib stimulated PC-9 model revealed that DHA could revert the Gefitinib resistance.

Conclusion

This is the first research that indicated the novel biochemical effect of DHA, which can help in overcoming the resistance of EGFR-TKI in NSCLC cells and broaden the horizon of the DHA supplementation during the NSCLC therapy.

Nuclear Factor κB Signaling and Its Related Non-coding RNAs in Cancer Therapy

Nuclear factor κB (NF-κB) acts as a nuclear factor that is composed of five main subunits. It is a pluripotent and crucial dimer transcription factor that has a close relationship with many serious illnesses, especially its influences on cell proliferation, inflammation, and cancer initiation and progression. NF-κB acts as part of the signaling pathway and determines its effect on the expression of several other genes, such as epidermal growth factor receptor (EGFR), p53, signal transducer and activator of transcription 3 (STAT3), and non-coding RNA (ncRNA). Continuous activation of the NF-κB signaling pathway has been seen in many cancer types. While the NF-κB signaling pathway is tightly regulated in physiological settings, quite frequently it is constitutively activated in cancer, and the molecular biology mechanism underlying the deregulated activation of NF-κB signaling remains unclear. In this review, we discuss the regulatory role and possible clinical significance of ncRNA (microRNA [miRNA] and long non-coding RNA [lncRNA]) in NF-κB signaling in cancer, including in the conversion of inflammation to carcinogenesis. Non-coding RNA plays an essential and complex role in the NF-κB signaling pathway. NF-κB activation can also induce the ncRNA status. Targeting NF-κB signaling by ncRNA is becoming a promising strategy of drug development and cancer treatment.

Particulate matter and the airway epithelium: the special case of the underground?

Airborne particulate matter (PM) is a leading driver of premature mortality and cardiopulmonary morbidity, associated with exacerbations of asthma and chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, and lung cancer. The airway epithelium, as the principal site of PM deposition, is critical to the effects of, and initial response to, PM. A key mechanism by which PM exerts its effects is the generation of reactive oxygen species (ROS), inducing antioxidant and inflammatory responses in exposed epithelial cells. However, much of what is known about the effects of PM is based on research using particulates from urban air. PM from underground railways is compositionally highly distinct from urban PM, being rich in metals associated with wheel, rail and brake wear and electrical arcing and component wear, which endows underground PM with potent ROS-generating capacity. In addition, underground PM appears to be more inflammogenic than urban PM in epithelial cells, but there is a lack of research into effects on exposed individuals, especially those with underlying health conditions. This review summarises current knowledge about the effects of PM on the airway epithelium, how the effects of underground PM may be different to urban PM and the potential health consequences and mitigation strategies for commuters and workers in underground railways.

Airborne particulate matter in underground railways is much more concentrated and metal-rich than that found above ground. The evidence surrounding what this might mean for effects on the airways of exposed commuters and staff is limited and inconsistent.http://bit.ly/2KtcorT

The Role of Fgf Signaling on Epithelial Cell Differentiation in Mouse Vagina

BACKGROUND/AIM

The mouse vagina exhibits stratified squamous epithelium, which is comprised of multiple cell layers. We previously showed that erbB signaling, induced by epithelial estrogen receptor 1 (ESR1), is required for the initial differentiation of the epithelium. However, the downstream effector that mediates terminal differentiation in the apical layers remains elusive. The contribution of fibroblast growth factor (FGF) to vaginal epithelial cell differentiation was investigated.

MATERIALS AND METHODS

Vaginas from wild-type or epithelium-specific Esr1 conditional knockout (cKO) mice were analyzed using immunohistochemistry and quantitative real-time RT-PCR.

RESULTS

Of the FGF ligands examined, Fgf22 mRNA was significantly induced following estrogen treatment. Furthermore, FGF downstream signaling, phosphorylated FRS2 and ERK1/2 were exclusively expressed in the apical layers of the vaginal epithelium. No changes in such expression were observed in the Esr1 cKO mice.

CONCLUSION

FGF-ERK/MAPK pathway may be a main inducer of terminal differentiation in the mouse vaginal epithelium.

Human Neutrophil Elastase Induces MUC5AC Overexpression in Chronic Rhinosinusitis Through miR-146a

Background

The pathogenesis of chronic rhinosinusitis (CRS) is not yet clear. microRNAs are widely involved in a number of physiological and pathological processes, of which microRNA-146a (miR-146a) plays an important role in innate immunity, inflammatory response, and other pathophysiological processes. Mucins (MUCs) are important components of secreted mucus, of which MUC5AC is the major MUC secreted in the normal airway.

Objective

This study was performed to examine human neutrophil elastase (HNE)-induced MUC5AC overexpression in CRS via miR-146a.

Methods

miR-146a, HNE, epidermal growth factor receptor (EGFR), and MUC5AC expression in the sinonasal mucosa were determined using quantitative real-time polymerase chain reaction (qRT-PCR). EGFR, phosphorylated EGFR (pEGFR), and MUC5AC expression were determined in primary cultures of human nasal epithelial cells (HNECs). We examined the expression of miR-146a, MUC5AC, EGFR, and pEGFR by transfecting HNECs with miR-146a mimics and negative control (NC). Moreover, dual-luciferase reporter gene assays were used to validate EGFR as an hsa-miR-146a target gene.

Results

miR-146a was significantly downregulated, and HNE, EGFR, and MUC5AC were upregulated in CRS patients both with and without nasal polyps. In the in vitro cell experiment, MUC5AC was significantly downregulated after use of an EGFR-specific inhibitor (AG1478). Upon addition of miR-146a inhibitor, miR-146a was downregulated, while MUC5AC was upregulated. MUC5AC was suppressed in normal primary HNECs by miR-146a mimic and pEGFR was downregulated. The results of dual-luciferase reporter assays showed that the luciferase activities were markedly inhibited in the pGL3-EGFR-3′ UTR+miR-146a mimic group compared with the pGL3+ miR-146a mimic group, suggesting that EGFR is a target gene for miR-146a.

Conclusion

In HNE-induced CRS, miR-146a downregulates the expression of MUC5AC by inhibiting the activation of EGFR, and EGFR is a target gene of miR-146a.

Osteopontin potentiates PM-induced IL-1α and IL-1β production via the ERK/JNK signaling pathway

Ambient particulate matter (PM) poses a great threat to global health and contributes to pulmonary inflammation. However, the potential mechanism of PM-induced inflammation of the lung remains unclear. Osteopontin (OPN) is a multifunctional protein that reportedly regulates inflammatory responses in different diseases. Here, we explored the expression of OPN with PM exposure in vivo and in vitro and attempted to elucidate the regulatory role of OPN in PM-induced airway inflammation. Our results showed that PM exposure increased the expression of OPN in the bronchial epithelium, serum, and bronchoalveolar lavage fluid (BALF) of mice. Moreover, PM induced OPN expression in human bronchial epithelial cells (HBECs) in a dose and time-dependent manner. In vitro, inflammatory cytokines such as IL-1α and IL-1β were increased in HBECs with PM exposure via the ERK and JNK signaling pathways. Recombinant human OPN could potentiate PM-induced expression of IL-1α and IL-1β, while OPN siRNA could alleviate PM-induced inflammatory responses in HBECs. Furthermore, we showed that OPN regulated PM-induced inflammatory cytokines via the ERK and JNK pathways in HBECs. This study shows for the first time the positive effect of OPN on PM-induced airway inflammation and contributes to a better understanding of its potential mechanism of action.