Airway mucins promote immunopathology in virus-exacerbated chronic obstructive pulmonary disease

Emerging cell and molecular targets for treating mucus hypersecretion in asthma

Mucus provides a protective barrier that is crucial for host defense in the lungs. However, excessive or abnormal mucus can have pathophysiological consequences in many pulmonary diseases, including asthma. Patients with asthma are treated with agents that relax airway smooth muscle and reduce airway inflammation, but responses are often inadequate. In part, this is due to the inability of existing therapeutic agents to directly target mucus. Accordingly, there is a critical need to better understand how mucus hypersecretion and airway plugging are affected by the epithelial cells that synthesize, secrete, and transport mucus components. This review highlights recent advances in the biology of mucin glycoproteins with a specific focus on MUC5AC and MUC5B, the chief macromolecular components of airway mucus. An improved mechanistic understanding of key steps in mucin production and secretion will help reveal novel potential therapeutic strategies.

Coarse-grained modeling and dynamics tracking of nanoparticles diffusion in human gut mucus

The gastrointestinal (GI) tract's mucus layer serves as a critical barrier and a mediator in drug nanoparticle delivery. The mucus layer's diverse molecular structures and spatial complexity complicates the mechanistic study of the diffusion dynamics of particulate materials. In response, we developed a bi-component coarse-grained mucus model, specifically tailored for the colorectal cancer environment, that contained the two most abundant glycoproteins in GI mucus: Muc2 and Muc5AC. This model demonstrated the effects of molecular composition and concentration on mucus pore size, a key determinant in the permeability of nanoparticles. Using this computational model, we investigated the diffusion rate of polyethylene glycol (PEG) coated nanoparticles, a widely used muco-penetrating nanoparticle. We validated our model with experimentally characterized mucus pore sizes and the diffusional coefficients of PEG-coated nanoparticles in the mucus collected from cultured human colorectal goblet cells. Machine learning fingerprints were then employed to provide a mechanistic understanding of nanoparticle diffusional behavior. We found that larger nanoparticles tended to be trapped in mucus over longer durations but exhibited more ballistic diffusion over shorter time spans. Through these discoveries, our model provides a promising platform to study pharmacokinetics in the GI mucus layer.

Selected updates on chronic obstructive pulmonary disease

PURPOSE OF REVIEW

Chronic obstructive pulmonary disease (COPD) is preventable disease and yet it remains the third greatest cause of death worldwide. This review focuses on recent updates in COPD research which have had an impact on our understanding of the epidemiology and pathophysiology of COPD.

RECENT FINDINGS

Epidemiological studies of COPD have moved towards trying to understand the global impact of COPD particularly in low- and middle-income countries where disease prevalence continues to increase. In addition, we are beginning to uncover the impact of air pollution on COPD development with recent work showing a relationship between air pollution and COPD exacerbations. Advances in understanding early origins and early development of COPD have the potential to intervene earlier in the disease course to prevent disease progression. Although biomarkers such as peripheral blood eosinophilia have led to trials of biologic agents in COPD suggesting we may be entering an exciting new biologic era in COPD.

SUMMARY

Recent advances suggest there may be a relationship between air pollution and COPD exacerbations. This requires further research to influence environmental policy. New clinical trials of biologics targeting TH2 inflammation in COPD suggest that targeted treatments with biologics may be a possibility COPD.

NLRP3 inflammasome mediates abnormal epithelial regeneration and distal lung remodeling in silica‑induced lung fibrosis

NOD-like receptor protein 3 (NLRP3) inflammasome is closely related to silica particle‑induced chronic lung inflammation but its role in epithelial remodeling, repair and regeneration in the distal lung during development of silicosis remains to be elucidated. The present study aimed to determine the effects of the NLRP3 inflammasome on epithelial remodeling and cellular regeneration and potential mechanisms in the distal lung of silica‑treated mice at three time points. Pulmonary function assessment, inflammatory cell counting, enzyme‑linked immunosorbent assay, histological and immunological analyses, hydroxyproline assay and western blotting were used in the study. Single intratracheal instillation of a silica suspension caused sustained NLRP3 inflammasome activation in the distal lung. Moreover, a time‑dependent increase in airway resistance and a decrease in lung compliance accompanied progression of pulmonary fibrosis. In the terminal bronchiole, lung remodeling including pyroptosis (membrane‑distributed GSDMD+), excessive proliferation (Ki67+), mucus overproduction (mucin 5 subtype AC and B) and epithelial‑mesenchymal transition (decreased E‑Cadherin+ and increased Vimentin+), was observed by immunofluorescence analysis. Notably, aberrant spatiotemporal expression of the embryonic lung stem/progenitor cell markers SOX2 and SOX9 and ectopic distribution of bronchioalveolar stem cells were observed in the distal lung only on the 7th day after silica instillation (the early inflammatory phase of silicosis). Western blotting revealed that the Sonic hedgehog/Glioma‑associated oncogene (Shh/Gli) and Wnt/β‑catenin pathways were involved in NLRP3 inflammasome activation‑mediated epithelial remodeling and dysregulated regeneration during the inflammatory and fibrotic phases. Overall, sustained NLRP3 inflammasome activation led to epithelial remodeling in the distal lung of mice. Moreover, understanding the spatiotemporal profile of dysregulated epithelial repair and regeneration may provide a novel therapeutic strategy for inhalable particle‑related chronic inflammatory and fibrotic lung disease.

Reduced miR-513a-5p expression in COPD may regulate airway mucous cell hyperplasia through TFR1-dependent signaling

Airway mucous cell metaplasia and mucous hypersecretion is one of the key characteristic pathophysiological status of chronic obstructive pulmonary disease (COPD). micro(mi)RNAs are acknowledged as non-encoding RNA molecules playing important roles in gene expression regulation. In this study, we searched the Gene Expression Omnibus (GEO) database for the differentially expressed miRNAs between COPD and non-COPD controls with bioinformatics analysis. Finally, we focused on miR-513a-5p and investigated the potential mechanism by which miR-513a-5p regulates airway mucous hypersecretion and goblet cell metaplasia. A dual-luciferase reporter assay was then showing that miR-513a-5p targeted the 3'-UTR of TFR1 and inhibited its expression in vitro. In vivo transfection demonstrated that TFR1 downregulation partially blocked MUC5AC hypersecretion and goblet cell hyperplasia in COPD model rats. In vitro study, CSE increased the intracellular expression and secretion of MUC5AC by BEAS-2B branchial epithelial cells in the BEAS-2B cell and THP-1 cell coculture system. Coculture with either miR-513a-5p mimic-pretreated or TFR1-deficient THP-1 cells attenuated intracellular MUC5AC expression in BEAS-2B cells exposed to CSE. ELISA demonstrated that transfection of TFR1 siRNA or pretreatment with miR-513a-5p mimic reduced the secretion of inflammatory factors that are responsible for airway goblet cell hyperplasia, such as IL-1β, IL-13, and IL-17, by THP-1 cells after CSE stimulation. Our findings supported that miR-513a-5p/TFR1 signaling axis might activate macrophages as well as promote airway inflammation and airway mucous cell hyperplasia in COPD.

The mechanism of Sanzi Yangqin decoction for asthma treatment based on network pharmacology and experimental verification

BACKGROUND

Asthma is a chronic airway inflammatory disease characterized by airway inflammation, mucus hypersecretion, airway hyper-reactivity. Sanzi Yangqin Decoction (SZYQD) is widely prescribed for asthma treatment. Its anti-asthma activities have been reported in animal model, but the exact mechanism and targets of SZYQD in asthma treatment have not been fully elucidated.

METHODS

A network pharmacological approach was used to predict the active components, targets, and signalling pathways of SZYQD in asthma, including potential target prediction, protein‒protein interaction (PPI) network construction and analysis, and Gene Ont (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. The active ingredients were identified from the SZYQD, and were molecular docked according to the results of network pharmacology. A mouse model of asthma induced by ovalbumin (OVA) and lipopolysaccharide (LPS) was constructed to evaluate the therapeutic effect of SZYQD. Furthermore, the effects of SZYQD and its active ingredients were tested in vitro for regulating inflammation and MUC5AC expression (two main pathophysiologic abnormalities of asthma) in macrophages and airway epithelial cells by using Real-time PCR and western blotting.

RESULTS

A total of 28 active ingredients and 111 HUB genes were screened in the relevant databases, including three key ingredients (luteolin, β-carotene, and Sinapine) and nine core target genes (JUN, CTNNB1, IL10, TP53, AKT1, STAT3, TNF, IL6 and EGFR). KEGG and GO analysis indicated that the potential anti-asthmatic mechanisms of SZYQD were related to PI3K-Akt signalling pathway and response to lipopolysaccharide, etc. In the in vivo asthmatic model, our findings demonstrated that SZYQD exerted a protective effect against asthmatic mice induced by OVA and LPS through the inhibition of inflammation and mucus overproduction. Consistently, cell experiments showed that the SZYQD extract or the key active ingredients luteolin significantly decreased lipopolysaccharide (LPS)-induced IL-6 expression and activation of the NF-κB pathway in macrophages. In addition, SZYQD extract or luteolin inhibited activation of the AKT pathway and expression of MUC5AC induced by EGF in airway epithelial cells.

CONCLUSION

The anti-asthmatic mechanism of SZYQD might be associated with inhibiting inflammation and airway mucus hypersecretion by regulating the NF-κB and AKT signalling pathways as predicted by network pharmacology, which provides more evidence for the application of SZYQD in asthma treatment.

PDZ Peptide of the ZO-1 Protein Significantly Increases UTP-Induced MUC8 Anti-Inflammatory Mucin Overproduction in Human Airway Epithelial Cells

Mucus hyperproduction and hypersecretion are observed often in respiratory diseases. MUC8 is a glycoprotein synthesized by epithelial cells and generally expressed in the respiratory track. However, the physiological mechanism by which extracellular nucleotides induce MUC8 gene expression in human airway epithelial cells is unclear. Here, we show that UTP could induce MUC8 gene expression through P2Y2-PLCβ3-Ca2+ activation. Because the full-length cDNA sequence of MUC8 has not been identified, a specific siRNA-MUC8 was designed based on the partial cDNA sequence of MUC8. siRNA-MUC8 significantly increased TNF-α production and decreased IL-1Ra production, suggesting that MUC8 may downregulate UTP/P2Y2-induced airway inflammation. Interestingly, the PDZ peptide of ZO-1 protein strongly abolished UTP-induced TNF-α production and increased IL-1Ra production and MUC8 gene expression. In addition, the PDZ peptide dramatically increased the levels of UTP-induced ZO proteins and TEER (trans-epithelial electrical resistance). These results show that the anti-inflammatory mucin MUC8 may contribute to homeostasis, and the PDZ peptide can be a novel therapeutic candidate for UTP-induced airway inflammation.

Phenotypes, Etiotypes, and Endotypes of Exacerbations of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease is a major health problem with a high prevalence, a rising incidence, and substantial morbidity and mortality. Its course is punctuated by acute episodes of increased respiratory symptoms, termed exacerbations of chronic obstructive pulmonary disease (ECOPD). ECOPD are important events in the natural history of the disease, as they are associated with lung function decline and prolonged negative effects on quality of life. The present-day therapy for ECOPD with short courses of antibiotics and steroids and escalation of bronchodilators has resulted in only modest improvements in outcomes. Recent data indicate that ECOPD are heterogeneous, raising the need to identify distinct etioendophenotypes, incorporating traits of the acute event and of patients who experience recurrent events, to develop novel and targeted therapies. These characterizations can provide a complete clinical picture, the severity of which will dictate acute pharmacological treatment, and may also indicate whether a change in maintenance therapy is needed to reduce the risk of future exacerbations. In this review we discuss the latest knowledge of ECOPD types on the basis of clinical presentation, etiology, natural history, frequency, severity, and biomarkers in an attempt to characterize these events.

The Role of Mucin Expression in the Diagnosis of Oesophago-Gastric Cancer: A Systematic Literature Review

Survival in oesophago-gastric cancer (OGC) is poor due to early diagnostic challenges. Non-invasive risk stratification may identify susceptible patients with pre-malignant or benign disease. Following diagnostic confirmation with endoscopic biopsy, early OGC may be treated sooner. Mucins are transmembrane glycoproteins implicated in OGC with potential use as biomarkers of malignant transformation. This systematic review defines the role of mucins in OGC diagnosis. A literature search of MEDLINE, Web of Science, Embase and Cochrane databases was performed following PRISMA protocols for studies published January 1960-December 2022. Demographic data and data on mucin sampling and analysis methods were extracted. The review included 124 studies (n = 11,386 patients). Gastric adenocarcinoma (GAc) was the commonest OG malignancy (n = 101) followed by oesophageal adenocarcinoma (OAc, n = 24) and squamous cell carcinoma (OSqCc, n = 10). Mucins MUC1, MUC2, MUC5AC and MUC6 were the most frequently implicated. High MUC1 expression correlated with poorer prognosis and metastases in OSqCc. MUC2 expression decreases during progression from healthy mucosa to OAc, causing reduced protection from gastric acid. MUC5AC was upregulated, and MUC6 downregulated in GAc. Mucin expression varies in OGC; changes may be epigenetic or mutational. Profiling upper GI mucin expression in OGC, with pre-malignant, benign and healthy controls may identify potential early diagnostic biomarkers.

Multi-strain probiotics alleviate loperamide-induced constipation by adjusting the microbiome, serotonin, and short-chain fatty acids in rats

Constipation is one of the most common gastrointestinal (GI) disorders worldwide. The use of probiotics to improve constipation is well known. In this study, the effect on loperamide-induced constipation by intragastric administration of probiotics Consti-Biome mixed with SynBalance® SmilinGut (Lactobacillus plantarum PBS067, Lactobacillus rhamnosus LRH020, Bifidobacterium animalis subsp. lactis BL050; Roelmi HPC), L. plantarum UALp-05 (Chr. Hansen), Lactobacillus acidophilus DDS-1 (Chr. Hansen), and Streptococcus thermophilus CKDB027 (Chong Kun Dang Bio) to rats was evaluated. To induce constipation, 5 mg/kg loperamide was intraperitoneally administered twice a day for 7 days to all groups except the normal control group. After inducing constipation, Dulcolax-S tablets and multi-strain probiotics Consti-Biome were orally administered once a day for 14 days. The probiotics were administered 0.5 mL at concentrations of 2 × 10⁸ CFU/mL (G1), 2 × 10⁹ CFU/mL (G2), and 2 × 10¹⁰ CFU/mL (G3). Compared to the loperamide administration group (LOP), the multi-strain probiotics not only significantly increased the number of fecal pellets but also improved the GI transit rate. The mRNA expression levels of serotonin- and mucin-related genes in the colons that were treated with the probiotics were also significantly increased compared to levels in the LOP group. In addition, an increase in serotonin was observed in the colon. The cecum metabolites showed a different pattern between the probiotics-treated groups and the LOP group, and an increase in short-chain fatty acids was observed in the probiotic-treated groups. The abundances of the phylum Verrucomicrobia, the family Erysipelotrichaceae and the genus Akkermansia were increased in fecal samples of the probiotic-treated groups. Therefore, the multi-strain probiotics used in this experiment were thought to help alleviate LOP-induced constipation by altering the levels of short-chain fatty acids, serotonin, and mucin through improvement in the intestinal microflora.

IL-1 receptor antagonist attenuates proinflammatory responses to rhinovirus in airway epithelium

BACKGROUND

Rhinoviruses (RVs) are the most common trigger for asthma exacerbations, and there are currently no targeted therapies for viral-induced asthma exacerbations. RV infection causes neutrophilic inflammation, which is often resistant to effects of glucocorticoids. IL-1 receptor antagonist (IL-1RA) treatment reduces neutrophilic inflammation in humans challenged with inhaled endotoxin and thus may have therapeutic potential for RV-induced asthma exacerbations.

OBJECTIVE

We sought to test the hypothesis that IL-1RA treatment of airway epithelium reduces RV-mediated proinflammatory cytokine production, which is important for neutrophil recruitment.

METHODS

Human bronchial epithelial cells from deceased donors without prior pulmonary disease were cultured at air-liquid interface and treated with IL-13 to approximate an asthmatic inflammatory milieu. Human bronchial epithelial cells were infected with human RV-16 with or without IL-1RA treatment.

RESULTS

RV infection promoted the release of IL-1α and the neutrophil-attractant cytokines IL-6, IL-8, and CXCL10. Proinflammatory cytokine secretion was significantly reduced by IL-1RA treatment without significant change in IFN-β release or RV titer. In addition, IL-1RA reduced MUC5B expression after RV infection without impacting MUC5AC.

CONCLUSIONS

These data suggest that IL-1RA treatment significantly reduced proinflammatory cytokines while preserving the antiviral response. These results provide evidence for further investigation of IL-1RA as a novel targeted therapy against neutrophil-attractant cytokine release in RV-induced airway inflammatory responses.

A novel thiol-saccharide mucolytic for the treatment of muco-obstructive lung diseases

BACKGROUND

Mucin disulfide cross-links mediate pathologic mucus formation in muco-obstructive lung diseases. MUC-031, a novel thiol-modified carbohydrate compound, cleaves disulfides to cause mucolysis. The aim of this study was to determine the mucolytic and therapeutic effects of MUC-031 in sputum from patients with cystic fibrosis (CF) and mice with muco-obstructive lung disease (βENaC-Tg mice).

METHODS

We compared the mucolytic efficacy of MUC-031 and existing mucolytics (N-acetylcysteine (NAC) and recombinant human deoxyribonuclease I (rhDNase)) using rheology to measure the elastic modulus (G') of CF sputum, and we tested effects of MUC-031 on airway mucus plugging, inflammation and survival in βENaC-Tg mice to determine its mucolytic efficacy in vivo.

RESULTS

In CF sputum, compared to the effects of rhDNase and NAC, MUC-031 caused a larger decrease in sputum G', was faster in decreasing sputum G' by 50% and caused mucolysis of a larger proportion of sputum samples within 15 min of drug addition. Compared to vehicle control, three treatments with MUC-031 in 1 day in adult βENaC-Tg mice decreased airway mucus content (16.8±3.2 versus 7.5±1.2 nL·mm-2, p<0.01) and bronchoalveolar lavage cells (73 833±6930 versus 47 679±7736 cells·mL-1, p<0.05). Twice-daily treatment with MUC-031 for 2 weeks also caused decreases in these outcomes in adult and neonatal βENaC-Tg mice and reduced mortality from 37% in vehicle-treated βENaC-Tg neonates to 21% in those treated with MUC-031 (p<0.05).

CONCLUSION

MUC-031 is a potent and fast-acting mucolytic that decreases airway mucus plugging, lessens airway inflammation and improves survival in βENaC-Tg mice. These data provide rationale for human trials of MUC-031 in muco-obstructive lung diseases.

Pneumocystis Exacerbates Inflammation and Mucus Hypersecretion in a Murine, Elastase-Induced-COPD Model

Inflammation and mucus hypersecretion are frequent pathology features of chronic respiratory diseases such as asthma and COPD. Selected bacteria, viruses and fungi may synergize as co-factors in aggravating disease by activating pathways that are able to induce airway pathology. Pneumocystis infection induces inflammation and mucus hypersecretion in immune competent and compromised humans and animals. This fungus is a frequent colonizer in patients with COPD. Therefore, it becomes essential to identify whether it has a role in aggravating COPD severity. This work used an elastase-induced COPD model to evaluate the role of Pneumocystis in the exacerbation of pathology, including COPD-like lung lesions, inflammation and mucus hypersecretion. Animals infected with Pneumocystis developed increased histology features of COPD, inflammatory cuffs around airways and lung vasculature plus mucus hypersecretion. Pneumocystis induced a synergic increment in levels of inflammation markers (Cxcl2, IL6, IL8 and IL10) and mucins (Muc5ac/Muc5b). Levels of STAT6-dependent transcription factors Gata3, FoxA3 and Spdef were also synergically increased in Pneumocystis infected animals and elastase-induced COPD, while the levels of the mucous cell-hyperplasia transcription factor FoxA2 were decreased compared to the other groups. Results document that Pneumocystis is a co-factor for disease severity in this elastase-induced-COPD model and highlight the relevance of STAT6 pathway in Pneumocystis pathogenesis.

Airway-delivered short-chain fatty acid acetate boosts antiviral immunity during rhinovirus infection

BACKGROUND

Microbiota are recognized to play a major role in regulation of immunity through release of immunomodulatory metabolites such as short-chain fatty acids (SCFAs). Rhinoviruses (RVs) induce upper respiratory tract illnesses and precipitate exacerbations of asthma and chronic obstructive pulmonary disease through poorly understood mechanisms. Local interactions between SCFAs and antiviral immune responses in the respiratory tract have not been previously investigated.

OBJECTIVE

We sought to investigate whether pulmonary metabolite manipulation through lung-delivered administration of SCFAs can modulate antiviral immunity to RV infection.

METHODS

We studied the effects of intranasal administration of the SCFAs acetate, butyrate, and propionate on basal expression of antiviral signatures, and of acetate in a mouse model of RV infection and in RV-infected lung epithelial cell lines. We additionally assessed the effects of acetate, butyrate, and propionate on RV infection in differentiated human primary bronchial epithelial cells.

RESULTS

Intranasal acetate administration induced basal upregulation of IFN-β, an effect not observed with other SCFAs. Butyrate induced RIG-I expression. Intranasal acetate treatment of mice increased interferon-stimulated gene and IFN-λ expression during RV infection and reduced lung virus loads at 8 hours postinfection. Acetate ameliorated virus-induced proinflammatory responses with attenuated pulmonary mucin and IL-6 expression observed at day 4 and 6 postinfection. This interferon-enhancing effect of acetate was confirmed in human bronchial and alveolar epithelial cell lines. In differentiated primary bronchial epithelial cells, butyrate treatment better modulated IFN-β and IFN-λ gene expression during RV infection.

CONCLUSIONS

SCFAs augment antiviral immunity and reduce virus load and proinflammatory responses during RV infection.

Mucolytics for acute exacerbations of chronic obstructive pulmonary disease: a meta-analysis

This meta-analysis explored the safety and effectiveness of mucolytics as an add-on treatment for chronic obstructive pulmonary disease (COPD) exacerbations. Based on a pre-registered protocol and following Cochrane methods, we systematically searched for relevant randomised or quasi-randomised controlled trials (RCTs). We used the Risk of Bias v2 tool for appraising the studies and performed random-effect meta-analyses when appropriate. We assessed certainty of evidence using GRADE. This meta-analysis included 24 RCTs involving 2192 patients with COPD exacerbations, entailing at least some concerns of methodological bias. We demonstrated with moderate certainty that mucolytics increase the rate of treatment success (relative risk 1.37, 95% CI 1.08-1.73, n=383), while they also exert benefits on overall symptom scores (standardised mean difference 0.86, 95% CI 0.63-1.09, n=316), presence of cough at follow-up (relative risk 1.93, 95% CI 1.15-3.23) and ease of expectoration (relative risk 2.94, 95% CI 1.68-5.12). Furthermore, low or very low certainty evidence suggests mucolytics may also reduce future risk of exacerbations and improve health-related quality of life, but do not impact on breathlessness, length of hospital stay, indication for higher level of care or serious adverse events. Overall, mucolytics could be considered for COPD exacerbation management. These findings should be validated in further, rigorous RCTs.

The Pathology of Asthma: What Is Obstructing Our View?

Despite the advent of sophisticated and efficient new biologics to treat inflammation in asthma, the disease persists. Even following treatment, many patients still experience the well-known symptoms of wheezing, shortness of breath, and coughing. What are we missing? Here we examine the evidence that mucus plugs contribute to a substantial portion of disease, not only by physically obstructing the airways but also by perpetuating inflammation. In this way, mucus plugs may act as an immunogenic stimulus even in the absence of allergen or with the use of current therapeutics. The alterations of several parameters of mucus biology, driven by type 2 inflammation, result in sticky and tenacious sputum, which represents a potent threat, first due to the difficulties in expectoration and second by acting as a platform for viral, bacterial, or fungal colonization that allows exacerbations. Therefore, in this way, mucus plugs are an overlooked but critical feature of asthmatic airway disease.

Effective Component Compatibility of Bufei Yishen Formula III Which Regulates the Mucus Hypersecretion of COPD Rats via the miR-146a-5p/EGFR/MEK/ERK Pathway

Background

The effective-component compatibility of Bufei Yishen formula III (ECC-BYF III) with 5 ingredients (ginsenoside Rh1, astragaloside, icariin, nobiletin, and paeonol) has been shown to protect against chronic obstructive pulmonary disease (COPD). The present study aimed to observe the effects of ECC-BYF III in a COPD rat model and dissect its potential mechanisms in regulating mucus hypersecretion via the miR-146a-5p/epidermal growth factor receptor (EGFR)/MEK/ERK pathway.

Methods

COPD model rats were treated with normal saline, ECC-BYF III, or N-acetylcysteine (NAC). Pulmonary function, lung tissue histology with H & E and AB-PAS staining, expression levels of interleukin (IL)-4, IL-6, IL-1β, MUC5AC, MUC5B, and FOXA2 in lung tissues and the mRNA and proteins involved in the miR-146a-5p/EGFR/MEK/ERK pathway were evaluated.

Results

The COPD rats showed a significant decrease in the pulmonary function and serious pathological damage to the lung tissue. ECC-BYF III and NAC significantly improved the ventilation function and small airway pathological damage in the COPD rats. The goblet cells and the expression levels of IL-1β, IL-6, MUC5AC, and MUC5B were increased in the COPD rats and were significantly decreased after ECC-BYF III or NAC intervention. The expression levels of IL-4 and FOXA2 in the COPD rats were markedly decreased and were improved in the ECC-BYF III and NAC groups. ECC-BYF III appeared to have a potent effect in restoring the reduced expression of miR-146a-5p. The increased phosphorylation levels of EGFR, MEK, and ERK1/2 and the protein expression levels of SPDEF in the lungs of COPD rats could be significantly reduced by ECC-BYF III.

Conclusions

ECC-BYF III has a significant effect in improving the airway mucus hypersecretion in COPD model rats, as well as a protective effect against limited pulmonary function and injured lung histopathology. The protective effect of ECC-BYF III in reducing airway mucus hypersecretion in COPD may involve the miR-146a-5p/EGFR/MEK/ERK pathway.

Prevalence and Mechanisms of Mucus Accumulation in COVID-19 Lung Disease

Rationale: The incidence and sites of mucus accumulation and molecular regulation of mucin gene expression in coronavirus (COVID-19) lung disease have not been reported. Objectives: To characterize the incidence of mucus accumulation and the mechanisms mediating mucin hypersecretion in COVID-19 lung disease. Methods: Airway mucus and mucins were evaluated in COVID-19 autopsy lungs by Alcian blue and periodic acid-Schiff staining, immunohistochemical staining, RNA in situ hybridization, and spatial transcriptional profiling. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected human bronchial epithelial (HBE) cultures were used to investigate mechanisms of SARS-CoV-2-induced mucin expression and synthesis and test candidate countermeasures. Measurements and Main Results: MUC5B and variably MUC5AC RNA concentrations were increased throughout all airway regions of COVID-19 autopsy lungs, notably in the subacute/chronic disease phase after SARS-CoV-2 clearance. In the distal lung, MUC5B-dominated mucus plugging was observed in 90% of subjects with COVID-19 in both morphologically identified bronchioles and microcysts, and MUC5B accumulated in damaged alveolar spaces. SARS-CoV-2-infected HBE cultures exhibited peak titers 3 days after inoculation, whereas induction of MUC5B/MUC5AC peaked 7-14 days after inoculation. SARS-CoV-2 infection of HBE cultures induced expression of epidermal growth factor receptor (EGFR) ligands and inflammatory cytokines (e.g., IL-1α/β) associated with mucin gene regulation. Inhibiting EGFR/IL-1R pathways or administration of dexamethasone reduced SARS-CoV-2-induced mucin expression. Conclusions: SARS-CoV-2 infection is associated with a high prevalence of distal airspace mucus accumulation and increased MUC5B expression in COVID-19 autopsy lungs. HBE culture studies identified roles for EGFR and IL-1R signaling in mucin gene regulation after SARS-CoV-2 infection. These data suggest that time-sensitive mucolytic agents, specific pathway inhibitors, or corticosteroid administration may be therapeutic for COVID-19 lung disease.

Revealing lncRNA Biomarkers Related to Chronic Obstructive Pulmonary Disease Based on Bioinformatics

Background

Chronic obstructive pulmonary disease (COPD) is a common chronic disease of the respiratory tract, with high prevalence, high disability, and poor prognosis. However, the molecular mechanism of COPD needs to be further revealed.

Methods

We obtained the gene expression profile and miRNA expression profile of COPD patients from Gene Expression Omnibus (GEO) database, and the differentially expressed genes (DEGs) and differentially expressed miRNAs (DEmis) in COPD were identified. Subsequently, the COPD-related ceRNA network was constructed based on the interaction between lncRNA, miRNA, and mRNA using the lncACTdb database. Finally, the Cytoscape software was used to analyze the network topology and COPD-related lncRNAs.

Results

Firstly, the 519 DEGs and 17 DEmis were identified from COPD GEO datasets. GO enrichment showed that leukocyte chemotaxis, cell chemotaxis, and myeloid leukocyte migration were upregulated, and muscle and membrane repolarization-related biological progress were downregulated in COPD. KEGG pathway enrichment shows that the p53 pathway was upregulated in COPD. Hallmark enrichment showed that chronic neutrophil inflammation was a sign of the pathogenesis of COPD. Next, a ceRNA network including 93 DEGs, 2 DEmi, 463 lncRNAs, and 1157 DEG-lncRNA, DEmi-lncRNA, and DEmi-DEG interactions were obtained. The hub-lncRNA (the network is ranked in the top 10) as the core marker of COPD, including SNHG12, SLFNL1-AS1, KCNQ1OT1, XIST, EAF1-AS1, FOXD2-AS1, NORAD, PINK1-AS and RP11-69E11.4. And the cytoHubba analysis identified ATM, SMAD7 and HIF1A as hub genes of ceRNA network.

Conclusion

This study provides a landscape of ceRNA network of COPD, which help to reveal the underlying pathophysiological mechanisms of COPD and shed light on novel therapeutic strategies for COPD.

The emerging role of NOTCH3 receptor signalling in human lung diseases

The mammalian respiratory system or lung is a tree-like branching structure, and the main site of gas exchange with the external environment. Structurally, the lung is broadly classified into the proximal (or conducting) airways and the distal alveolar region, where the gas exchange occurs. In parallel with the respiratory tree, the pulmonary vasculature starts with large pulmonary arteries that subdivide rapidly ending in capillaries adjacent to alveolar structures to enable gas exchange. The NOTCH signalling pathway plays an important role in lung development, differentiation and regeneration post-injury. Signalling via the NOTCH pathway is mediated through activation of four NOTCH receptors (NOTCH1-4), with each receptor capable of regulating unique biological processes. Dysregulation of the NOTCH pathway has been associated with development and pathophysiology of multiple adult acute and chronic lung diseases. This includes accumulating evidence that alteration of NOTCH3 signalling plays an important role in the development and pathogenesis of chronic obstructive pulmonary disease, lung cancer, asthma, idiopathic pulmonary fibrosis and pulmonary arterial hypertension. Herein, we provide a comprehensive summary of the role of NOTCH3 signalling in regulating repair/regeneration of the adult lung, its association with development of lung disease and potential therapeutic strategies to target its signalling activity.

Advances in chronic obstructive pulmonary disease: management of exacerbations

Exacerbations of chronic obstructive pulmonary disease are important events to people living with this condition and a common cause of emergency hospital admission. In the absence of a confirmatory biomarker, an exacerbation remains a clinical diagnosis of exclusion and clinicians must be alert to alternative diagnoses. Most exacerbations are caused by airway infection, particularly with respiratory viruses. The mainstay of exacerbation treatment is an increase in the dose and/or frequency of short-acting beta-agonists, with short-course oral corticosteroids and/or antibiotics. Although there have been no new interventions to treat exacerbations in many years, there is still much variation in care and opportunity to improve outcomes. There has been a new focus on both the management of comorbidities and the optimisation of future care to reduce the risk of further events. This review summarises advances in managing exacerbations of chronic obstructive pulmonary disease, focusing on hospitalised patients.

The EGFR/ErbB inhibitor neratinib modifies the neutrophil phosphoproteome and promotes apoptosis and clearance by airway macrophages

Dysregulated neutrophilic inflammation can be highly destructive in chronic inflammatory diseases due to prolonged neutrophil lifespan and continual release of histotoxic mediators in inflamed tissues. Therapeutic induction of neutrophil apoptosis, an immunologically silent form of cell death, may be beneficial in these diseases, provided that the apoptotic neutrophils are efficiently cleared from the tissue. Previous research in our group identified ErbB inhibitors as able to induce neutrophil apoptosis and reduce neutrophilic inflammation both in vitro and in vivo. Here, we extend that work using a clinical ErbB inhibitor, neratinib, which has the potential to be repurposed in inflammatory diseases. We show that neratinib reduces neutrophilic migration o an inflammatory site in zebrafish larvae. Neratinib upregulates efferocytosis and reduces the number of persisting neutrophil corpses in mouse models of acute, but not chronic, lung injury, suggesting that the drug may have therapeutic benefits in acute inflammatory settings. Phosphoproteomic analysis of human neutrophils shows that neratinib modifies the phosphorylation of proteins regulating apoptosis, migration, and efferocytosis. This work identifies a potential mechanism for neratinib in treating acute lung inflammation by upregulating the clearance of dead neutrophils and, through examination of the neutrophil phosphoproteome, provides important insights into the mechanisms by which this may be occurring.