Bronchial inflammation and bacterial load in stable COPD is associated with TLR4 overexpression

Pyroptosis-Related Genes as Diagnostic Markers in Chronic Obstructive Pulmonary Disease and Its Correlation with Immune Infiltration

Background

Chronic obstructive pulmonary disease (COPD) stands as a predominant cause of global morbidity and mortality. This study aims to elucidate the relationship between pyroptosis-related genes (PRGs) and COPD diagnosis in the context of immune infiltration, ultimately proposing a PRG-based diagnostic model for predicting COPD outcomes.

Methods

Clinical data and PRGs of COPD patients were sourced from the GEO database. The "ConsensusClusterPlus" package was employed to generate molecular subtypes derived from PRGs that were identified through differential expression analysis and LASSO Cox analysis. A diagnostic signature including eight genes (CASP4, CASP5, ELANE, GPX4, NLRP1, GSDME, NOD1and IL18) was also constructed. Immune cell infiltration calculated by the ESTIMATE score, Stroma scores and Immune scores were also compared on the basis of pyroptosis-related molecular subtypes and the risk signature. We finally used qRT - PCR to detect the expression levels of eight genes in COPD patient and normal.

Results

The diagnostic model, anchored on eight PRGs, underwent validation with an independent experimental cohort. The area under the receiver operating characteristic (ROC) curves (AUC) for the diagnostic model showcased values of 0.809, 0.765, and 0.956 for the GSE76925, GSE8545, and GSE5058 datasets, respectively. Distinct expression patterns and clinical attributes of PRGs were observed between the comparative groups, with functional analysis underscoring a disparity in immune-related functions between them.

Conclusion

In this study, we developed a potential as diagnostic biomarkers for COPD and have a significant role in modulating the immune response. Such insights pave the way for novel diagnostic and therapeutic strategies for COPD.

DNA of neutrophil extracellular traps promote NF-κB-dependent autoimmunity via cGAS/TLR9 in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterised by persistent airway inflammation even after cigarette smoking cessation. Neutrophil extracellular traps (NETs) have been implicated in COPD severity and acute airway inflammation induced by short-term cigarette smoke (CS). However, whether and how NETs contribute to sustained airway inflammation in COPD remain unclear. This study aimed to elucidate the immunoregulatory mechanism of NETs in COPD, employing human neutrophils, airway epithelial cells (AECs), dendritic cells (DCs), and a long-term CS-induced COPD mouse model, alongside cyclic guanosine monophosphate-adenosine monophosphate synthase and toll-like receptor 9 knockout mice (cGAS--/-, TLR9-/-); Additionally, bronchoalveolar lavage fluid (BALF) of COPD patients was examined. Neutrophils from COPD patients released greater cigarette smoke extract (CSE)-induced NETs (CSE-NETs) due to mitochondrial respiratory chain dysfunction. These CSE-NETs, containing oxidatively-damaged DNA (NETs-DNA), promoted AECs proliferation, nuclear factor kappa B (NF-κB) activation, NF-κB-dependent cytokines and type-I interferons production, and DC maturation, which were ameliorated/reversed by silencing/inhibition of cGAS/TLR9. In the COPD mouse model, blocking NETs-DNA-sensing via cGAS-/- and TLR9-/- mice, inhibiting NETosis using mitoTEMPO, and degrading NETs-DNA with DNase-I, respectively, reduced NETs infiltrations, airway inflammation, NF-κB activation and NF-κB-dependent cytokines, but not type-I interferons due to IFN-α/β receptor degradation. Elevated NETs components (myeloperoxidase and neutrophil elastase activity) in BALF of COPD smokers correlated with disease severity and NF-κB-dependent cytokine levels, but not type-I interferon levels. In conclusion, NETs-DNA promotes NF-κB-dependent autoimmunity via cGAS/TLR9 in long-term CS exposure-induced COPD. Therefore, targeting NETs-DNA and cGAS/TLR9 emerges as a potential strategy to alleviate persistent airway inflammation in COPD.

Assessment of NLRP3 inflammasome activation in patients with chronic obstructive pulmonary disease before and after lung transplantation

The interplay between purinergic receptors as well as pattern recognition receptors like Toll-like receptors (TLRs) and NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) might have a role in the pathogenesis of chronic obstructive pulmonary disease (COPD). The aim of this study was to determine and compare the concentrations of the damage-associated molecular patterns (DAMPs) heat shock protein 70 (Hsp70) and adenosine triphosphate (ATP), and gene expression of their respective receptors as well as NLRP3 inflammasome-related molecules in the peripheral blood of patients with end-stage COPD before and 1 year after lung transplantation (LT). Lung function was assessed by spirometry and diffusion capacity for carbon monoxide (DLCO). Quantitative polymerase chain reaction (qPCR) was applied for detection of TLR2, TLR4, P2X7R, P2Y2R, IL1B, CASP1, and NLRP3 expression. High-sensitivity ELISA kits were used for extracellular (e) Hsp70 and IL-1β, and luminescence assay for eATP measurements. Concentrations of eHsp70 and eATP as well as IL-1β were significantly increased in the plasma of end-stage COPD patients and significantly decreased after LT. In addition, TLR4, P2Y2R, IL1B, CASP1, and NLRP3 expression was up-regulated in COPD patients before LT, while it was significantly suppressed after LT. In conclusion, it could be assumed that NLRP3 inflammasome is activated in the peripheral blood of end-stage COPD patients and that eHsp70 and eATP could be responsible for its activation through triggering their receptors. On the other hand, previously enhanced pro-inflammatory reactions seem to be suppressed to the healthy population levels in lung recipients without allograft rejection.

Metabolic pathways in immune senescence and inflammaging: Novel therapeutic strategy for chronic inflammatory lung diseases. An EAACI position paper from the Task Force for Immunopharmacology

The accumulation of senescent cells drives inflammaging and increases morbidity of chronic inflammatory lung diseases. Immune responses are built upon dynamic changes in cell metabolism that supply energy and substrates for cell proliferation, differentiation, and activation. Metabolic changes imposed by environmental stress and inflammation on immune cells and tissue microenvironment are thus chiefly involved in the pathophysiology of allergic and other immune-driven diseases. Altered cell metabolism is also a hallmark of cell senescence, a condition characterized by loss of proliferative activity in cells that remain metabolically active. Accelerated senescence can be triggered by acute or chronic stress and inflammatory responses. In contrast, replicative senescence occurs as part of the physiological aging process and has protective roles in cancer surveillance and wound healing. Importantly, cell senescence can also change or hamper response to diverse therapeutic treatments. Understanding the metabolic pathways of senescence in immune and structural cells is therefore critical to detect, prevent, or revert detrimental aspects of senescence-related immunopathology, by developing specific diagnostics and targeted therapies. In this paper, we review the main changes and metabolic alterations occurring in senescent immune cells (macrophages, B cells, T cells). Subsequently, we present the metabolic footprints described in translational studies in patients with chronic asthma and chronic obstructive pulmonary disease (COPD), and review the ongoing preclinical studies and clinical trials of therapeutic approaches aiming at targeting metabolic pathways to antagonize pathological senescence. Because this is a recently emerging field in allergy and clinical immunology, a better understanding of the metabolic profile of the complex landscape of cell senescence is needed. The progress achieved so far is already providing opportunities for new therapies, as well as for strategies aimed at disease prevention and supporting healthy aging.

Revealing the clinical effect and biological mechanism of acupuncture in COPD: A review

BACKGROUND

To provide new ideas for the clinical and mechanism research of acupuncture in the treatment of chronic obstructive pulmonary disease (COPD), this study systematically reviews clinical research and the progress of basic research of acupuncture in the treatment of COPD.

METHODS

PubMed and Web of Science databases were searched using acupuncture and COPD as keywords in the last 10 years, and the included literature was determined according to exclusion criteria.

FINDINGS

Acupuncture can relieve clinical symptoms, improve exercise tolerance, anxiety, and nutritional status, as well as hemorheological changes (blood viscosity), reduce the inflammatory response, and reduce the duration and frequency of COPD in patients with COPD. Mechanistically, acupuncture inhibits M1 macrophage activity, reduces neutrophil infiltration, reduces inflammatory factor production in alveolar type II epithelial cells, inhibits mucus hypersecretion of airway epithelial cells, inhibits the development of chronic inflammation in COPD, and slows tissue structure destruction. Acupuncture may control pulmonary COPD inflammation through the vagal-cholinergic anti-inflammatory, vagal-adrenomedullary-dopamine, vagal-dual-sensory nerve fiber-pulmonary, and CNS-hypothalamus-orexin pathways. Furthermore, acupuncture can increase endogenous cortisol levels by inhibiting the HPA axis, thus improving airway antioxidant capacity and reducing airway inflammation in COPD. In conclusion, the inhibition of the chronic inflammatory response is the key mechanism of acupuncture treatment for COPD.

Toll-like receptor 4: A potential therapeutic target for multiple human diseases

The immune response plays a pivotal role in the pathogenesis of diseases. Toll-like receptor 4 (TLR4), as an intrinsic immune receptor, exhibits widespread in vivo expression and its dysregulation significantly contributes to the onset of various diseases, encompassing cardiovascular disorders, neoplastic conditions, and inflammatory ailments. This comprehensive review centers on elucidating the architectural and distributive characteristics of TLR4, its conventional signaling pathways, and its mode of action in diverse disease contexts. Ultimately, this review aims to propose novel avenues and therapeutic targets for clinical intervention.

Endoplasmic reticulum stress: a vital process and potential therapeutic target in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD), a chronic and progressive disease characterized by persistent respiratory symptoms and progressive airflow obstruction, has attracted extensive attention due to its high morbidity and mortality. Although the understanding of the pathogenesis of COPD has gradually increased because of increasing evidence, many questions regarding the mechanisms involved in COPD progression and its deleterious effects remain unanswered. Recent advances have shown the potential functions of endoplasmic reticulum (ER) stress in causing airway inflammation, emphasizing the vital role of unfolded protein response (UPR) pathways in the development of COPD.

METHODS

A comprehensive search of major databases including PubMed, Scopus, and Web of Science was conducted to retrieve original research articles and reviews related to ER stress, UPR, and COPD.

RESULTS

The common causes of COPD, namely cigarette smoke (CS) and air pollutants, induce ER stress through the generation of reactive oxygen species (ROS). UPR promotes mucus secretion and further plays a dual role in the cell apoptosis-autophagy axis in the development of COPD. Existing drug research has indicated the potential of UPR as a therapeutic target for COPD.

CONCLUSIONS

ER stress and UPR activation play significant roles in the etiology, pathogenesis, and treatment of COPD and discuss whether related genes can be used as biomarkers and therapeutic targets.

The Mechanisms of Resistin-Like Molecule-β-Mediated Airway Inflammation in Chronic Obstructive Pulmonary Disease via Autophagy

Background

The role of irreversible airway inflammatory damage in chronic obstructive pulmonary disease (COPD) progression is evident. Autophagy is an essential process in the cellular material metabolic cycle, and a family of resistant vegetative molecules may be involved in the COPD autophagic process. In this study, we investigated the mechanism of resistin-like molecule β (RELMβ) in COPD smoking-induced autophagy.

Methods

Firstly, the expression differences of RELMβ and autophagy markers between COPD and control groups were analyzed in the Gene Expression Omnibus (GEO) datasets and clinical specimens. Secondly, in vitro and in vivo experiments were conducted using immunoblotting, immunofluorescence, immunohistochemistry, and other methods to investigate the mechanism by which RELMβ promotes airway inflammation through autophagy in a cigarette smoke extract-induced 16HBE cell inflammation model and a cigarette smoke-induced COPD-like mouse model. In addition, immunoprecipitation was used to analyze the binding of RELMβ to the membrane protein TLR4.

Results

The expression of RELMβ and autophagy genes p62 and LC3B in lung tissue of COPD patients was significantly increased. RELMβ can mediate the activation of autophagy in 16HBE cells, and through autophagy, it increases the expression of inflammatory cytokines in a cigarette smoke extract-induced 16HBE cell inflammation model. RELMβ promotes cigarette smoke-induced COPD-like mouse airway inflammation through autophagy, and RELMβ can mediate signal transduction through the cell membrane receptor TLR4.

Conclusion

The RELMβ binds to TLR4 to encourage signal transduction and that RELMβ can promote inflammation in smoky COPD lungs through autophagy.

Bacterial load and related innate immune response in the bronchi of rapid decliners with chronic obstructive pulmonary disease

BACKGROUND

Characterization of COPD patients with rapid lung functional decline is of interest for prognostic and therapeutic reasons. We recently reported an impaired humoral immune response in rapid decliners.

OBJECTIVE

To determine the microbiota associated to markers of innate immune host response in COPD patients with rapid lung functional decline.

METHODS

In COPD patients monitored for at least 3 years (mean ± SD: 5.8 ± 3 years) for lung functional decline, the microbiota and related markers of immune response was measured in bronchial biopsies of patients with different lung functional decline (rate of FEV1% lung functional decline: no decline FEV1%, ≤20 ml/year n = 21, slow decline FEV1%, >20 ≤ 70 ml/year, n = 14 and rapid decline FEV1%, >70 ml/year, n = 15) using qPCR for microbiota and immunohistochemistry for cell-receptors and inflammatory markers.

MAIN RESULTS

Pseudomonas aeruginosa and Streptococcus pneumoniae were increased in rapid decliners vs slow decliners, S. pneumoniae was also increased compared to non decliners. In all patients, S. pneumoniae (copies/ml) positively correlated with pack-years consumption, lung function decline, TLR4, NOD1, NOD2 scored in bronchial epithelium and NOD1/mm² in lamina propria.

CONCLUSION

These data show an imbalance of microbiota components in rapid decliners which is associated to the expression of the related cell-receptors in all COPD patients. These findings may help in the prognostic stratification and treatment of patients.

The therapeutic potential of quercetin for cigarette smoking-induced chronic obstructive pulmonary disease: a narrative review

Quercetin is a flavonoid with antioxidant and anti-inflammatory properties. Quercetin has potentially beneficial therapeutic effects for several diseases, including cigarette smoking-induced chronic obstructive pulmonary disease (CS-COPD). Many studies have shown that quercetin's antioxidant and anti-inflammatory properties have positive therapeutic potential for CS-COPD. In addition, quercetin's immunomodulatory, anti-cellular senescence, mitochondrial autophagy-modulating, and gut microbiota-modulating effects may also have therapeutic value for CS-COPD. However, there appears to be no review of the possible mechanisms of quercetin for treating CS-COPD. Moreover, the combination of quercetin with common therapeutic drugs for CS-COPD needs further refinement. Therefore, in this article, after introducing the definition and metabolism of quercetin, and its safety, we comprehensively presented the pathogenesis of CS-COPD related to oxidative stress, inflammation, immunity, cellular senescence, mitochondrial autophagy, and gut microbiota. We then reviewed quercetin's anti-CS-COPD effects, performed by influencing these mechanisms. Finally, we explored the possibility of using quercetin with commonly used drugs for treating CS-COPD, providing a basis for future screening of excellent drug combinations for treating CS-COPD. This review has provided meaningful information on quercetin's mechanisms and clinical use in treating CS-COPD.

The role of HMGB1/RAGE/TLR4 signaling pathways in cigarette smoke-induced inflammation in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory disease with irreversible and continuous progression. It has become the fifth most burdensome disease and the third most deadly disease globally. Therefore, the prevention and treatment of COPD are urgent, and it is also important to clarify the pathogenesis of it. Smoking is the main and most common risk factor for COPD. Cigarette smoke (CS) can cause lung inflammation and other pathological mechanisms in the airways and lung tissue. Airway inflammation is one of the important mechanisms leading to the pathogenesis of COPD. Recent studies have shown that high mobility group box 1 (HMGB1) is involved in the occurrence and development of respiratory diseases, including COPD. HMGB1 is a typical damage-associated molecular pattern (DAMP) protein, which mainly exerts its activity by binding to the receptor for advanced glycation end products (RAGE) and toll-like receptor 4 (TLR4) and further participate in the process of airway inflammation. Studies have shown that the abnormal expression of HMGB1, RAGE, and TLR4 are related to inflammation in COPD. Herein, we discuss the roles of HMGB1, RAGE, and TLR4 in CS/cigarette smoke extract-induced inflammation in COPD, providing a new target for the diagnosis, treatment and prevention of COPD.

Occupational COPD-The most under-recognized occupational lung disease?

Chronic obstructive pulmonary disease (COPD) is caused by exposure to noxious particles and gases. Smoking is the main risk factor, but other factors are also associated with COPD. Occupational exposure to vapours, gases, dusts and fumes contributes to the development and progression of COPD, accounting for a population attributable fraction of 14%. Workplace pollutants, in particular inorganic dust, can initiate airway damage and inflammation, which are the hallmarks of COPD pathogenesis. Occupational COPD is still underdiagnosed, mainly due to the challenges of assessing the occupational component of the disease in clinical settings, especially if other risk factors are present. There is a need for specific education and training for clinicians, and research with a focus on evaluating the role of occupational exposure in causing COPD. Early diagnosis and identification of occupational causes is very important to prevent further decline in lung function and to reduce the health and socio-economic burden of COPD. Establishing details of the occupational history by general practitioners or respiratory physicians could help to define the occupational burden of COPD for individual patients, providing the first useful interventions (smoking cessation, best therapeutic management, etc.). Once patients are diagnosed with occupational COPD, there is a wide international variation in access to specialist occupational medicine and public health services, along with limitations in workplace and income support. Therefore, a strong collaboration between primary care physicians, respiratory physicians and occupational medicine specialists is desirable to help manage COPD patients' health and social issues.

Effects of Vitamin D on Respiratory Function and Immune Status for Patients with Chronic Obstructive Pulmonary Disease (COPD): A Systematic Review and Meta-Analysis

Background

Many studies have demonstrated that vitamin D has clinical benefits when used to treat patients with chronic obstructive pulmonary disease (COPD). However, most of these studies have insufficient samples or inconsistent results. The aim of this meta-analysis was to evaluate the effects of vitamin D therapy in patients with COPD.

Methods

We performed a comprehensive retrieval in the following electronic databases: PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang Data, and Chinese Scientific Journals Database (VIP). Two trained reviewers identified relevant studies, extracted data information, and then assessed the methodical quality by the Cochrane risk of bias assessment tool, independently. Then, the meta-analyses were conducted by RevMan 5.4, binary variables were represented by risks ratio (RR), and continuous variables were represented by mean difference (MD) or standardized mean difference (SMD) to assess the efficacy of vitamin D therapy in patients with COPD. Then, publication bias assessment was conducted by funnel plot analysis. Finally, the quality of evidence was assessed by the GRADE system.

Results

A total of 15 articles involving 1598 participants were included in this study. The overall results showed a statistical significance of vitamin D therapy in patients with COPD which can significantly improve forced expiratory volume in 1 second (FEV1) (MD: 5.69, 95% CI: 5.01-6.38,P < 0.00001,I2 = 51%) and FEV1/FVC (SMD:0.49, 95% CI: 0.39-0.60,P < 0.00001,I2 = 84%); and serum 25 (OH)D (SMD:1.21, 95% CI:1.07-1.34,P < 0.00001,I2 = 98%) also increase CD3+ Tcells (MD: 6.67, 95% CI: 5.34-8.00,P < 0.00001,I2 = 78%) and CD4+ T cells (MD: 6.00, 95% CI: 5.01-7.00,P < 0.00001,I2 = 65%); and T lymphocyte CD4+/CD8+ ratio (MD: 0.41, 95% CI: 0.20-0.61,P = 0.0001,I2 = 95%) obviously decrease CD8+ Tcells(SMD: -0.83, 95% CI: -1.05- -0.06,P < 0.00001,I2 = 82%), the times of acute exacerbation (RR: 0.40, 95% CI: 0.28-0.59,P < 0.00001,I2 = 0%), and COPD assessment test (CAT) score (MD: -3.77, 95% CI: -5.86 - -1.68,P = 0.0004,I2 = 79%).

Conclusions

Our analysis indicated that vitamin D used in patients with COPD could improve the lung function (FEV1 and FEV1/FVC), the serum 25(OH)D, CD3+ T cells, CD4 + T cells, and T lymphocyte CD4+/CD8+ ratio and reduce CD8+ T cells, acute exacerbation, and CAT scores.

Pathogenesis of COPD at the cellular and molecular level

Chronic inflammatory responses in the lung of patients with stable mild-to severe forms of COPD play a central role in the definition, comprehension and monitoring of the disease state. A better understanding of the COPD pathogenesis can't avoid a detailed knowledge of these inflammatory changes altering the functional health of the lung during the disease progression. We here summarize and discuss the role and principal functions of the inflammatory cells populating the large, small airways and lung parenchyma of patients with COPD of increasing severity in comparison with healthy control subjects: T and B lymphocytes, NK and Innate Lymphoid cells, macrophages, and neutrophils. The differential inflammatory distribution in large and small airways of patients is also discussed. Furthermore, relevant cellular mechanisms controlling the homeostasis and the "normal" balance of these inflammatory cells and of structural cells in the lung, such as autophagy, apoptosis, necroptosis and pyroptosis are as well presented and discussed in the context of the COPD severity.

Perilla Leaf Extract (PLE) Attenuates COPD Airway Inflammation via the TLR4/Syk/PKC/NF-κB Pathway In Vivo and In Vitro

Chronic obstructive pulmonary disease (COPD) is a complex and heterogeneous disease characterized by persistent airflow limitation but still lacking effective treatments. Perilla frutescens (L.) Britt., an important traditional medicinal plant with excellent antioxidant and anti-inflammatory properties, is widely used for the treatment of respiratory disease in China. However, its protective activity and mechanism against COPD airway inflammation have not been fully studied. Here, the anti-inflammatory effects of the PLE were investigated, and its underlying mechanisms were then elucidated. The presented results suggested a notable effect of the PLE on airway inflammation of COPD, by significantly ameliorating inflammatory cell infiltration in lung tissue, lessening leukocytes (lymphocytes, neutrophils, and macrophages) and inflammatory mediators (interleukin 4 (IL-4), IL-6, IL-17A, interferon γ (IFN-γ), and tumor necrosis factor α (TNF-α)) in the bronchoalveolar lavage fluid (BALF) of cigarette smoke (CS)/lipopolysaccharide (LPS)-induced COPD mice in vivo and inhibiting the production of inflammatory factors (nitric oxide (NO), IL-6, and TNF-α) and intracellular reactive oxygen species (ROS) in LPS-stimulated RAW264.7 cells in vitro. For further extent, PLE treatment significantly suppressed the expression and phosphorylation of TLR4, Syk, PKC, and NF-κB p65 in vivo and their mRNA in vitro. Subsequently, by co-treating with their inhibitors in vitro, its potential mechanism via TLR4/Syk/PKC/NF-κB p65 signals was disclosed. In summary, the obtained results indicated a noteworthy effective activity of the PLE on COPD inflammation, and partly, the TLR4/Syk/PKC/NF-κB p65 axis might be the potential mechanism.

Involvement of the Innate Immune System in the Pathogenesis of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a common, socially significant disease characterized by progressive airflow limitation due to chronic inflammation in the bronchi. Although the causes of COPD are considered to be known, the pathogenesis of the disease continues to be a relevant topic of study. Mechanisms of the innate immune system are involved in various links in the pathogenesis of COPD, leading to persistence of chronic inflammation in the bronchi, their bacterial colonization and disruption of lung structure and function. Bronchial epithelial cells, neutrophils, macrophages and other cells are involved in the development and progression of the disease, demonstrating multiple compromised immune mechanisms.

Dexmedetomidine alleviates airway hyperresponsiveness and allergic airway inflammation through the TLR4/NF‑κB signaling pathway in mice

Dexmedetomidine (DEX) suppresses inflammatory responses and protects against organ injury. The aim of the present study was to investigate the effect of DEX on airway hyperresponsiveness (AHR) and allergic airway inflammation, as well as its underlying mechanism of action in a murine model of ovalbumin (OVA)-induced asthma. A total of 30 female BALB/c mice were divided into 6 groups (n=5 mice/group): Control, OVA, OVA + DEX (20, 30 or 50 µg/kg) and OVA + TAK-242 [a toll-like receptor 4 (TLR4) inhibitor]. The mice were intraperitoneally injected with 20, 30 or 50 µg/kg DEX 1 h before OVA challenge. AHR to inhaled methacholine (Mch) was measured, and the mice were sacrificed 24 h after the last challenge. AHR following Mch inhalation was measured using the FlexiVent apparatus. Hematoxylin and eosin, periodic acid-Schiff and Wright-Giemsa staining was performed to evaluate inflammatory cell infiltration in the lung tissue. The levels of IL-4, IL-5 and IL-13 in the bronchoalveolar lavage fluid were analyzed using ELISA, and their mRNA expression levels in the lung tissue were examined using reverse transcription-quantitative PCR. The protein expression of TLR4, NF-κB and phosphorylated (p)NF-κB in the lung tissue was also detected using immunohistochemistry. In the murine OVA-induced asthma model, DEX decreased AHR following Mch inhalation and reduced the infiltration of inflammatory cells. IL-4, IL-5 and IL-13 levels in the bronchoalveolar lavage fluid were significantly lower following DEX treatment. Furthermore, DEX treatment inhibited the expression of TLR4, NF-κB and p-NF-κB in the lung tissue and exhibited a similar effect to TAK-242 treatment. In conclusion, DEX may attenuate AHR and allergic airway inflammation by inhibiting the TLR4/NF-κB pathway. These results suggested that DEX may represent a potential anti-inflammatory agent for the treatment and management of patients with asthma.

Bacterial and viral infections and related inflammatory responses in chronic obstructive pulmonary disease

In chronic obstructive pulmonary disease (COPD) patients, bacterial and viral infections play a relevant role in worsening lung function and, therefore, favour disease progression. The inflammatory response to lung infections may become a specific indication of the bacterial and viral infections. We here review data on the bacterial-viral infections and related airways and lung parenchyma inflammation in stable and exacerbated COPD, focussing our attention on the prevalent molecular pathways in these different clinical conditions. The roles of macrophages, autophagy and NETosis are also briefly discussed in the context of lung infections in COPD. Controlling their combined response may restore a balanced lung homeostasis, reducing the risk of lung function decline. KEY MESSAGE Bacteria and viruses can influence the responses of the innate and adaptive immune system in the lung of chronic obstructive pulmonary disease (COPD) patients. The relationship between viruses and bacterial colonization, and the consequences of the imbalance of these components can modulate the inflammatory state of the COPD lung. The complex actions involving immune trigger cells, which activate innate and cell-mediated inflammatory responses, could be responsible for the clinical consequences of irreversible airflow limitation, lung remodelling and emphysema in COPD patients.

Targeting the Toll-like receptor pathway as a therapeutic strategy for neonatal infection

Toll-like receptors (TLRs) are crucial transmembrane receptors that form part of the innate immune response. They play a role in the recognition of various microorganisms and their elimination from the host. TLRs have been proposed as vital immunomodulators in the regulation of multiple neonatal stressors that extend beyond infection such as oxidative stress and pain. The immune system is immature at birth and takes some time to become fully established. As such, babies are especially vulnerable to sepsis at this early stage of life. Findings suggest a gestational age-dependent increase in TLR expression. TLRs engage with accessory and adaptor proteins to facilitate recognition of pathogens and their activation of the receptor. TLRs are generally upregulated during infection and promote the transcription and release of proinflammatory cytokines. Several studies report that TLRs are epigenetically modulated by chromatin changes and promoter methylation upon bacterial infection that have long-term influences on immune responses. TLR activation is reported to modulate cardiorespiratory responses during infection and may play a key role in driving homeostatic instability observed during sepsis. Although complex, TLR signaling and downstream pathways are potential therapeutic targets in the treatment of neonatal diseases. By reviewing the expression and function of key Toll-like receptors, we aim to provide an important framework to understand the functional role of these receptors in response to stress and infection in premature infants.

Microbiota and IPF: hidden and detected relationships

Lung microbiota (LM) is an interesting new way to consider and redesign pathogenesis and possible therapeutic approach to many lung diseases, such as idiopathic pulmonary fibrosis (IPF), which is an interstitial pneumonia with bad prognosis. Chronic inflammation is the basis but probably not the only cause of lung fibrosis and although the risk factors are not completely clear, endogenous factors (e.g. gastroesophageal reflux) and environmental factors like cigarette smoking, industrial dusts, and precisely microbial agents could contribute to the IPF development. It is well demonstrated that many bacteria can cause epithelial cell injuries in the airways through induction of a host immune response or by activating flogosis mediators following a chronic, low-level antigenic stimulus. This persistent host response could influence fibroblast responsiveness suggesting that LM may play a role in repetitive alveolar injury in IPF. We reviewed literature regarding not only bacteria but also the role of virome and mycobiome in IPF. In fact, some viruses such as hepatitis C virus or certain fungi could be etiological agents or co-factors in the IPF progress. We aim to illustrate how the cross-talk between different local microbiotas throughout specific axis and immune modulation governed by microorganisms could be at the basis of lung dysfunctions and IPF development. Finally, since the future direction of medicine will be personalized, we suggest that the analysis of LM could be a goal to research new therapies also in IPF.

Nucleotide-Oligomerizing Domain-1 Activation Exaggerates Cigarette Smoke-Induced Chronic Obstructive Pulmonary-Like Disease in Mice

Introduction

Chronic obstructive pulmonary disease (COPD) is a progressive condition related to abnormal inflammatory responses. As an inflammatory driver, nucleotide-binding oligomerizing domain-1 (NOD1) is highly expressed in pulmonary inflammatory cells; however, the roles of NOD1 in COPD are unknown.

Methods

A COPD mouse model was established by lipopolysaccharides tracheal instillation plus cigarette smoke (CS) exposure. NOD1 activation was induced by C12-iE-DAP (iE) treatment in both control and COPD mice. Inflammatory infiltration, pulmonary histological damage and gene expression were measured to evaluate the lung function of treated mice.

Results

The results showed that NOD1 was up-regulated in COPD mice, which significantly exaggerated CS-induced impairment of lung function, demonstrated by increased airway resistance, functional residual capacity and pulmonary damages. Mechanistically, NOD1 activation strongly activated the TLR4/NF-κB signaling pathway and then increased inflammatory responses and promoted the secretion of inflammatory cytokines.

Discussion

This study demonstrates that NOD1 is an important risk factor in the progression of COPD; therefore, targeting NOD1 in lung tissues is a potential strategy for COPD treatment.

Role of Toll-Like Receptor 2 in Regulation of T-Helper Immune Response in Chronic Obstructive Pulmonary Disease

Objective

According to modern views, the differences in the clinical course of chronic obstructive pulmonary disease (COPD) are associated with certain types of T-helper (Th) immune response. Recent data have shown that toll-like receptor 2 (TLR2) is involved in the development of Th immune response. However, TLR2-mediated regulation of Th subpopulation balance in COPD needs to be elucidated. The aim of our work is to determine the mechanisms of TLR2-mediated regulation of Th immune response in COPD of varying severity.

Methods

The study included 323 smokers/ex-smokers with stable COPD (GOLD I, GOLD II, and GOLD III) and 97 healthy nonsmokers (control group). Serum levels of Th1 (TNF-α and IFN-γ), Th2 (IL-4), Th17 (IL-6 and IL-17A), Treg (IL-10) cytokines, and the percentage of peripheral blood Th cells expressing TLR2 (CD4⁺CD282⁺) were assessed by flow cytometry. Serum concentrations of IL-21 (Th17) and TGF-β1 (Treg) were measured using the ELISA method. The predominant Th cytokine profile in serum was determined by calculating the ratios between levels of Th1 and Th17 cytokines. Spearman's correlation test was performed.

Results

Patients with COPD GOLD II and III with Th1 and Th17 cytokine profiles exhibited an increase in the percentage of CD4⁺CD282⁺ cells compared to the control group. In COPD GOLD I–III, positive correlations between CD4⁺CD282⁺ cell frequency and Th17 cytokine levels (IL-6, IL-17A, and IL-21) were found. In COPD GOLD I, IL-10 concentration was negatively correlated with the percentages of studied cells; in COPD GOLD II, a positive correlation between these parameters was noted.

Conclusions

Enhanced TLR2 expression on CD4⁺ cells shifts cytokine profile toward Th17 phenotype that plays a crucial role in COPD progression. The level of TLR2 expression on peripheral blood CD4⁺ cells may be considered as a biomarker for diagnosing and predicting the progression of COPD.

Malnutrition, poor post-natal growth, intestinal dysbiosis and the developing lung

In extremely preterm infants, poor post-natal growth, intestinal dysbiosis and bronchopulmonary dysplasia are common, and each is associated with long-term complications. The central hypothesis that this review will address is that these three common conditions are interrelated. Challenges to studying this hypothesis include the understanding that malnutrition and poor post-natal growth are not synonymous and that there is not agreement on what constitutes a normal intestinal microbiota in this evolutionarily new population. If this hypothesis is supported, further study of whether "correcting" intestinal dysbiosis in extremely preterm infants reduces postnatal growth restriction and/or bronchopulmonary dysplasia is indicated.

Role of Atypical Chemokines and Chemokine Receptors Pathways in the Pathogenesis of COPD

Chronic obstructive pulmonary disease (COPD) represents a heightened inflammatory response in the lung generally resulting from tobacco smoking-induced recruitment and activation of inflammatory cells and/or activation of lower airway structural cells. Several mediators can modulate activation and recruitment of these cells, particularly those belonging to the chemokines (conventional and atypical) family. There is emerging evidence for complex roles of atypical chemokines and their receptors (such as high mobility group box 1 (HMGB1), antimicrobial peptides, receptor for advanced glycosylation end products (RAGE) or toll-like receptors (TLRs)) in the pathogenesis of COPD, both in the stable disease and during exacerbations. Modulators of these pathways represent potential novel therapies for COPD and many are now in preclinical development. Inhibition of only a single atypical chemokine or receptor may not block inflammatory processes because there is redundancy in this network. However, there are many animal studies that encourage studies for modulating the atypical chemokine network in COPD. Thus, few pharmaceutical companies maintain a significant interest in developing agents that target these molecules as potential antiinflammatory drugs. Antibody-based (biological) and small molecule drug (SMD)-based therapies targeting atypical chemokines and/or their receptors are mostly at the preclinical stage and their progression to clinical trials is eagerly awaited. These agents will most likely enhance our knowledge about the role of atypical chemokines in COPD pathophysiology and thereby improve COPD management.

Circ_0038467 regulates lipopolysaccharide-mediated cell proliferation, apoptosis, and inflammatory response by miR-195-5p/TLR4 axis through NF-κB pathway in MRC-5 cells

Infantile pneumonia (IP) is an acute lower respiratory infection and brings a heavy burden to children health. Circular RNAs (circRNAs) participate in the regulation of pneumonia process. In this research, the effects of circ_0038467 in regulating lipopolysaccharide (LPS)-induced cell injury and underlying mechanism were revealed. Results showed that circ_0038467 expression and TLR4 protein level were upregulated, while miR-195-5p expression was downregulated in LPS-induced MRC-5 cells. Circ_0038467 silencing restored LPS-mediated inhibition on cell proliferation and promotion on apoptosis and inflammatory response. Additionally, circ_0038467 acted as a sponge of miR-195-5p, which was further revealed to target TLR4. MiR-195-5p inhibitor reversed circ_0038467 silencing-mediated influences under LPS treatment. Furthermore, LPS-activated NF-κB pathway was partly blocked by circ_0038467 silencing, which was restrained by TLR4 overexpression. Circ_0038467 silencing protected MRC-5 cells from LPS-induced injury by miR-195-5p/TLR4 axis through NF-κB pathway, providing a theoretical basis for circRNA-directed IP therapy.

Sulforaphane suppresses lipopolysaccharide- and Pam3CysSerLys4-mediated inflammation in chronic obstructive pulmonary disease via toll-like receptors

Chronic obstructive pulmonary disease (COPD) is a progressive inflammatory disease of the airway that represents a large global disease burden. Inflammation is a prominent feature of COPD and represents an important target for treatment. Toll‐like receptors (TLRs) are pattern recognition receptors that detect invading microorganisms and nonmicrobial endogenous molecules to trigger inflammatory responses during host defense and tissue repair. The TLR signaling pathway is closely linked to the pathogenesis of COPD. Sulforaphane (SFN), an isothiocyanate derived from cruciferous vegetables, is well known for its anti‐inflammatory activities. However, the molecular function of SFN in inhibition of COPD inflammation has yet to be fully elucidated. In this study, we investigated the effects of SFN on lipopolysaccharide (LPS)‐ or Pam3CysSerLys4 (Pam3CSK4)‐induced inflammation in monocyte‐derived macrophages (MDMs) from patients with COPD. MDMs from patients with COPD showed higher expression levels of TLR2, TLR4 and downstream myeloid differentiation factor 88 (MyD88) than healthy controls, along with increased secretion of interleukin‐6 (IL‐6) and tumor necrosis factor‐α (TNF‐α) (P < 0.05). Stimulation with TLR ligands (Pam3CSK4 and LPS) up‐regulated the levels of TLR2, TLR4 and MyD88 in MDMs from patients with COPD and induced the release of IL‐6 and TNF‐α (P < 0.05). Pretreatment of MDMs from patients with COPD with SFN significantly suppressed Pam3CSK4‐ or LPS‐induced TLR2, TLR4 and MyD88 expression, along with a reduction in the production of IL‐6 and TNF‐α (P < 0.05). Collectively, these data indicate that SFN exerts its anti‐inflammatory activity in COPD by modulating the TLR pathway. SFN may represent a potential therapeutic agent for the treatment of COPD.

RAGE and TLR4 differentially regulate airway hyperresponsiveness: Implications for COPD

BACKGROUND

The receptor for advanced glycation end products (RAGE) and Toll-like receptor 4 (TLR4) is implicated in COPD. Although these receptors share common ligands and signalling pathways, it is not known whether they act in concert to drive pathological processes in COPD. We examined the impact of RAGE and/or TLR4 gene deficiency in a mouse model of COPD and also determined whether expression of these receptors correlates with airway neutrophilia and airway hyperresponsiveness (AHR) in COPD patients.

METHODS

We measured airway inflammation and AHR in wild-type, RAGE^-/- , TLR4^-/- and TLR4^-/- RAGE^-/- mice following acute exposure to cigarette smoke (CS). We also examined the impact of smoking status on AGER (encodes RAGE) and TLR4 bronchial gene expression in patients with and without COPD. Finally, we determined whether expression of these receptors correlates with airway neutrophilia and AHR in COPD patients.

RESULTS

RAGE^-/- mice were protected against CS-induced neutrophilia and AHR. In contrast, TLR4^-/- mice were not protected against CS-induced neutrophilia and had more severe CS-induced AHR. TLR4^-/- RAGE^-/- mice were not protected against CS-induced neutrophilia but were partially protected against CS-induced mediator release and AHR. Current smoking was associated with significantly lower AGER and TLR4 expression irrespective of COPD status, possibly reflecting negative feedback regulation. However, consistent with preclinical findings, AGER expression correlated with higher sputum neutrophil counts and more severe AHR in COPD patients. TLR4 expression did not correlate with neutrophilic inflammation or AHR.

CONCLUSIONS

Inhibition of RAGE but not TLR4 signalling may protect against airway neutrophilia and AHR in COPD.

Participation of ABCA1 Transporter in Pathogenesis of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is the important medical and social problem. According to modern concepts, COPD is a chronic inflammatory disease, macrophages play a key role in its pathogenesis. Macrophages are heterogeneous in their functions, which is largely determined by their immunometabolic profile, as well as the features of lipid homeostasis, in which the ATP binding cassette transporter A1 (ABCA1) plays an essential role. The objective of this work is the analysis of the ABCA1 protein participation and the function of reverse cholesterol transport in the pathogenesis of COPD. The expression of the ABCA1 gene in lung tissues takes the second place after the liver, which indicates the important role of the carrier in lung function. The participation of the transporter in the development of COPD consists in provision of lipid metabolism, regulation of inflammation, phagocytosis, and apoptosis. Violation of the processes in which ABCA1 is involved may be a part of the pathophysiological mechanisms, leading to the formation of a heterogeneous clinical course of the disease.

The role of mucin 1 in respiratory diseases

Recent evidence has demonstrated that mucin 1 (MUC1) is involved in many pathological processes that occur in the lung. MUC1 is a transmembrane protein mainly expressed by epithelial and hematopoietic cells. It has a receptor-like structure, which can sense the external environment and activate intracellular signal transduction pathways through its cytoplasmic domain. The extracellular domain of MUC1 can be released to the external environment, thus acting as a decoy barrier to mucosal pathogens, as well as serving as a serum biomarker for the diagnosis and prognosis of several respiratory diseases such as lung cancer and interstitial lung diseases. Furthermore, bioactivated MUC1-cytoplasmic tail (CT) has been shown to act as an anti-inflammatory molecule in several airway infections and mediates the expression of anti-inflammatory genes in lung diseases such as chronic rhinosinusitis, chronic obstructive pulmonary disease and severe asthma. Bioactivated MUC1-CT has also been reported to interact with several effectors linked to cellular transformation, contributing to the progression of respiratory diseases such as lung cancer and pulmonary fibrosis. In this review, we summarise the current knowledge of MUC1 as a promising biomarker and drug target for lung disease.

IL-32 exacerbates adenoid hypertrophy via activating NLRP3-mediated cell pyroptosis, which promotes inflammation

Adenoid hypertrophy (AH) is a common pediatric disease caused by inflammatory stimulation. The pro-inflammatory cytokine IL-32 has been reported to promote airway inflammation and also be involved in the pyroptosis pathway. However, whether IL-32 can contribute to AH by mediating pyroptosis remains to be elucidated. The present study aimed to investigate the role of IL-32 in AH and determine the potential underlying mechanisms. Adenoid tissues were collected from healthy children and children with AH, and the expression of IL-32, NACHT LRR and PYD domains-containing protein 3 (NLRP3) and IL-1β in normal and hypertrophic tissues were measured. Human nasal epithelial cells (HNEpCs) were exposed to a series of IL-32 concentrations. HNEpCs with or without IL-32 silencing were stimulated with lipopolysaccharide (LPS), and cell proliferation, cell apoptosis, gasdermin D (GSDMD) activation, production of inflammatory cytokines and the expression levels of proteins related to the potential mechanisms were evaluated by Cell Counting Kit-8, flow cytometry, immunofluorescence staining, ELISA and western blot assays, respectively. The results showed that IL-32, NLRP3 and IL-1β exhibited higher expression in adenoid tissues with AH compared with normal tissues. In HNEpC cells, treatment with IL-32 (2 and 10 ng/ml) promoted cell proliferation, while 50 ng/ml IL-32 inhibited cell proliferation at 12, 24 and 48 h post-treatment. IL-32 (2, 10 and 50 ng/ml) also resulted in differing degrees of apoptosis, GSDMD activation, release of IL-1β, IL-6 and TNF-α, and increased protein expression levels of NLRP3, cleaved-caspase-1, activated GSDMD, nucleotide-binding oligomerization domain-containing protein (NOD) 1/2 and Toll-like receptor (TLR)4 in a concentration-dependent manner. In addition, compared with the LPS group, IL-32 knockdown significantly inhibited LPS-induced enhancement of cell proliferation, cell apoptosis, GSDMD activation and production of inflammatory cytokines, and reversed the increased protein expression of NLRP3, cleaved-caspase-1, activated GSDMD, NOD1/2 and TLR4. In conclusion, IL-32 may play a role in the progression of AH via promoting inflammation, and the potential mechanism may involve the activation of NLRP3-mediated pyroptosis.

E-cig vapor condensate alters proteome and lipid profiles of membrane rafts: impact on inflammatory responses in A549 cells

Electronic cigarettes (e-cigs) are battery-operated heating devices that aerosolize e-liquid, typically containing nicotine and several other chemicals, which is then inhaled by a user. Over the past decade, e-cigs have gained immense popularity among both smokers and non-smokers. One reason for this is that they are advertised as a safe alternative to conventional cigarettes. However, the recent reports of e-cig use associated lung injury have ignited a considerable debate about the relative harm and benefits of e-cigs. The number of reports about e-cig-induced inflammation and pulmonary health is increasing as researchers seek to better understand the effects of vaping on human health. In line with this, we investigated the molecular events responsible for the e-cig vapor condensate (ECVC)-mediated inflammation in human lung adenocarcinoma type II epithelial cells (A549). In an attempt to limit the variables caused by longer ingredient lists of flavored e-cigs, tobacco-flavored ECVC (TF-ECVC±nicotine) was employed for this study. Interestingly, we observed significant upregulation of cytokines and chemokines (IL-6, IL-8, and MCP-1) in A549 cells following a 48 h TF-ECVC challenge. Furthermore, there was a significant increase in the expression of pattern recognition receptors TLR-4 and NOD-1, lipid raft-associated protein caveolin-1, and transcription factor NF-кB in TF-ECVC with and/or without nicotine-challenged lung epithelial cells. Our results further demonstrate the harboring of TLR-4 and NOD-1 in the caveolae of TF-ECVC-challenged A549 cells. Proteomic and lipidomic analyses of lipid raft fractions from control and challenged cells revealed a distinct protein and lipid profile in TF-ECVC (w/wo nicotine)-exposed A549 cells. Interestingly, the inflammatory effects of TF-ECVC (w/wo nicotine) were inhibited following the caveolin-1 knockdown, thus demonstrating a critical role of caveolae raft-mediated signaling in eliciting inflammatory responses upon TF-ECVC challenge. Graphical Abstract Graphical Abstract.

NOD2 induces VCAM-1 and ET-1 gene expression via NF-κB in human umbilical vein endothelial cells with muramyl dipeptide stimulation

OBJECTIVES

Endothelial dysfunction is involved in various aspects of vascular biology and different stages of cardiovascular diseases (CVDs). Nucleotide-binding oligomerization domain-containing protein (NOD) 2, a pivotal innate immune receptor for muramyl dipeptide (MDP), has been reported to be a central regulator in CVDs. Previously, we reported that NOD2 played a leading role in MDP-triggered oxidative stress in endothelial cells (ECs). However, whether NOD2 participates in the regulatory mechanism of vascular cell adhesion molecule‑1 (VCAM-1) and endothelin‑1 (ET-1) expression was not elucidated.

METHODS

Human umbilical vein endothelial cells (HUVECs) were stimulated with MDP for 12 h. mRNA expression of VCAM‑1 and ET‑1 was detected using real time polymerase chain reaction (PCR). Scrambled control small interfering RNA (siRNA) and NOD2 siRNA were transfected into HUVECs using Lipofectamine 2000 reagent (Invitrogen, Waltham, MA, USA). Furthermore, pyrrolidine dithiocarbamate was adopted to investigate the effect of nuclear factor κB (NF-κB) on NOD2-mediated VCAM‑1 and ET‑1 gene expression in MDP-treated HUVECs.

RESULTS

Data showed that MDP significantly increased VCAM‑1 and ET‑1 mRNA expression, which was dependent on NOD2. In addition, NF-κB inhibition suppressed NOD2-mediated gene expression of VCAM‑1 and ET‑1.

CONCLUSION

Collectively, we confirmed NOD2 aggravated VCAM‑1 and ET‑1 gene expression through NF-κB in HUVECs treated with MDP.

miRNA-486-5p Promotes COPD Progression by Targeting HAT1 to Regulate the TLR4-Triggered Inflammatory Response of Alveolar Macrophages

Purpose

The aim of this study was to investigate the role of miRNA-486-5p in chronic obstructive pulmonary disease (COPD) progression and the underlying molecular mechanisms.

Materials and Methods

Aberrant miRNA expression profiles between smokers and nonsmokers, and those between COPD patients and normal subjects were analyzed using microarray datasets and reverse-transcriptase quantitative polymerase chain reaction (qPCR). Enzyme-linked immunosorbent assay was used to determine the levels of inflammatory cytokines in cell supernatants. Expression levels of inflammatory cytokines, HAT1, TLR4, and miR-486-5p, were determined using qPCR or Western blotting. Luciferase reporter assays and fluorescence in situ hybridization were used to confirm the regulatory interaction between miR-486-6p and HAT1.

Results

miR-486-5p was significantly upregulated in the COPD and smoker groups compared to the control group, as demonstrated using bioinformatics analysis and validated using qPCR assay of alveolar macrophages and peripheral monocytes. Moreover, miR-486-5p expression was significantly correlated with the expression of IL-6, IL-8, TNF-α, and IFN-γ. Luciferase reporter assays confirmed that miR-486-5p directly targeted HAT1, and cellular localization showed that miR-486-5p and HAT1 were highly expressed in the cytoplasm. miR-486-5p overexpression led to a significant upregulation of TLR4 and a significant downregulation of HAT1. Inversely, miR-486-5p inhibition led to a significant downregulation of TLR4 and a significant upregulation of HAT1. HAT1 knockdown using siRNA significantly upregulated the expression of TLR4, IL-6, IL-8, TNF-α, and IFN-γ.

Conclusion

miR-486-5p was differentially expressed in the alveolar macrophages of COPD patients. miR-486-5p overexpression may enhance the TLR4-triggered inflammatory response in COPD patients by targeting HAT1.

Role of Lung Microbiome in Innate Immune Response Associated With Chronic Lung Diseases

Respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), lung fibrosis, and lung cancer, pose a huge socio-economic burden on society and are one of the leading causes of death worldwide. In the past, culture-dependent techniques could not detect bacteria in the lungs, therefore the lungs were considered a sterile environment. However, the development of culture-independent techniques, particularly 16S rRNA sequencing, allowed for the detection of commensal microbes in the lung and with further investigation, their roles in disease have since emerged. In healthy individuals, the predominant commensal microbes are of phylum Firmicutes and Bacteroidetes, including those of the genera Veillonella and Prevotella. In contrast, pathogenic microbes (Haemophilus, Streptococcus, Klebsiella, Pseudomonas) are often associated with lung diseases. There is growing evidence that microbial metabolites, structural components, and toxins from pathogenic and opportunistic bacteria have the capacity to stimulate both innate and adaptive immune responses, and therefore can contribute to the pathogenesis of lung diseases. Here we review the multiple mechanisms that are altered by pathogenic microbiomes in asthma, COPD, lung cancer, and lung fibrosis. Furthermore, we focus on the recent exciting advancements in therapies that can be used to restore altered microbiomes in the lungs.

Oral Primo-Colonizing Bacteria Modulate Inflammation and Gene Expression in Bronchial Epithelial Cells

The microbiota of the mouth disperses into the lungs, and both compartments share similar phyla. Considering the importance of the microbiota in the maturation of the immunity and physiology during the first days of life, we hypothesized that primo-colonizing bacteria of the oral cavity may induce immune responses in bronchial epithelial cells. Herein, we have isolated and characterized 57 strains of the buccal cavity of two human newborns. These strains belong to Streptococcus, Staphylococcus, Enterococcus, Rothia and Pantoea genera, with Streptococcus being the most represented. The strains were co-incubated with a bronchial epithelial cell line (BEAS-2B), and we established their impact on a panel of cytokines/chemokines and global changes in gene expression. The Staphylococcus strains, which appeared soon after birth, induced a high production of IL-8, suggesting they can trigger inflammation, whereas the Streptococcus strains were less associated with inflammation pathways. The genera Streptococcus, Enterococcus and Pantoea induced differential profiles of cytokine/chemokine/growth factor and set of genes associated with maturation of morphology. Altogether, our results demonstrate that the microorganisms, primo-colonizing the oral cavity, impact immunity and morphology of the lung epithelial cells, with specific effects depending on the phylogeny of the strains.

The Role of Toll-Like Receptors 2 and 4 in the Pathogenesis of Chronic Obstructive Pulmonary Disease

Currently, chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality worldwide. The determination of immune mechanisms of inflammation in the disease presents an important challenge for fundamental medical research. According to modern views, Toll-like receptors (TLRs), among which TLR2 and TLR4 play a key role, are one of the essential components of inflammatory process in COPD. This review focuses on following aspects: the role of TLR2 and TLR4 in the initiation of inflammatory process in COPD; the mechanisms of influence of various exogenous factors (cigarette smoke, suspended particulate matter, and bacteria) on the expression of TLR2 and TLR4; the contribution of these TLRs to the T-helper (Th) immune response development in COPD, in particular to the Th17 immune response, which contributes to the progression of the disease and therapeutic implications of TLR2 and TLR4 in COPD.

Evaluation of Innate Immune Mediators Related to Respiratory Viruses in the Lung of Stable COPD Patients

Background: Little is known about the innate immune response to viral infections in stable Chronic Obstructive Pulmonary Disease (COPD). Objectives: To evaluate the innate immune mediators related to respiratory viruses in the bronchial biopsies and lung parenchyma of stable COPD patients. Methods: We evaluated the immunohistochemical (IHC) expression of Toll-like receptors 3-7-8-9 (TLR-3-7-8-9), TIR domain-containing adaptor inducing IFNβ (TRIF), Interferon regulatory factor 3 (IRF3), Phospho interferon regulatory factor 3 (pIRF3), Interferon regulatory factor 7 (IRF7), Phospho interferon regulatory factor 7 (pIRF7), retinoic acid-inducible gene I (RIG1), melanoma differentiation-associated protein 5 (MDA5), Probable ATP-dependent RNA helicase DHX58 (LGP2), Mitochondrial antiviral-signaling protein (MAVS), Stimulator of interferon genes (STING), DNA-dependent activator of IFN regulatory factors (DAI), forkhead box protein A3(FOXA3), Interferon alfa (IFNα), and Interferon beta (IFNβ) in the bronchial mucosa of patients with mild/moderate (n = 16), severe/very severe (n = 1618) stable COPD, control smokers (CS) (n = 1612), and control non-smokers (CNS) (n = 1612). We performed similar IHC analyses in peripheral lung from COPD (n = 1612) and CS (n = 1612). IFNα and IFNβ were assessed in bronchoalveolar lavage (BAL) supernatant from CNS (n = 168), CS (n = 169) and mild/moderate COPD (n = 1612). Viral load, including adenovirus-B, -C, Bocavirus, Respiratory syncytial Virus (RSV), Human Rhinovirus (HRV), Coronavirus, Influenza virus A (FLU-A), Influenza virus B (FLU-B), and Parainfluenzae-1 were measured in bronchial rings and lung parenchyma of COPD patients and the related control group (CS). Results: Among the viral-related innate immune mediators, RIG1, LGP2, MAVS, STING, and DAI resulted well expressed in the bronchial and lung tissues of COPD patients, although not in a significantly different mode from control groups. Compared to CS, COPD patients showed no significant differences of viral load in bronchial rings and lung parenchyma. Conclusions: Some virus-related molecules are well-expressed in the lung tissue and bronchi of stable COPD patients independently of the disease severity, suggesting a “primed” tissue environment capable of sensing the potential viral infections occurring in these patients.

Cyclic Peptide Extracts Derived From Pseudostellaria heterophylla Ameliorates COPD via Regulation of the TLR4/MyD88 Pathway Proteins

We have explored the method of extraction and purification of cyclic-peptide extract (CPE) from Pseudostellaria heterophylla (Miq.) Pax. (Taizishen, TZS), characterized the structure about cyclic-peptide compounds and investigated the biological activity of CPE attenuating chronic obstructive pulmonary disease (COPD) in rats. The CPE from TZS was obtained by ethyl acetate, petroleum ether, hot water extraction, and alcohol-precipitation. Cyclic-peptide structures were distinguished using ultra-high performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS). Rats were induced by solid combustibles smoke (SCS) for the COPD model, and the anti-COPD activity of CPE was detected using lung airway resistance and dynamic lung compliance, as well as pulmonary tissue hematoxylin and eosin (HE) staining. The relevant inflammatory cytokines were assayed by enzyme-linked immunosorbent assay (ELISA). CPE obtained from TZS contained 12 cyclic-peptide constituents; the purity was up to 92.94%. CPE (200, 400, or 500 mg/kg/day) was given to SCS-induced COPD model rats orally for 15 days. The results showed that in rats given CPE (400 mg/kg/day) there was a sharp fall in lung airway resistance but a rise in dynamic lung compliance. The image analysis of lung tissue sections suggested that CPE could decrease the degree of alveolar destruction (p <0.05), alleviate lung inflammation, increase alveolar space, and improve the infiltration of inflammatory cells. CPE was found to reduce the levels of TNF-α, but increase IL-10, adjusting multiple cytokines in rat serum; the TLR4 mRNA, MyD88 mRNA and AP-1 mRNA levels, the expressing levels of p-JNK, p-p38 and p-TAK1 protein were significantly down regulated in rat alveolar macrophages. CPE intervention could improve the pulmonary ventilation function on COPD rats, which may be related to its effect in inhibiting the abnormal activation of the TLR4-MyD88-JNK/p38 pathway. This is the first report that the CPE of TZS lessens the severity of COPD episodes. The new preparation process of CPEs implements the anticipated goal, which is to refine CPE and actualize quality control.

Distinct anti-proliferative effects of herbal melanin on human acute monocytic leukemia THP-1 cells and embryonic kidney HEK293 cells

BACKGROUND

Herbal melanin (HM) is a dark pigment extracted from the seed coat of Nigella sativa L. and known to exert biological effects via toll-like receptor 4 (TLR4). Recently, TLR4 was described as involved in natural programmed cell death (apoptosis). Tumor and embryonic cells are used as in vitro cellular models for drug and anti-cancer agent screening. To date, no cytotoxic studies have been reported of HM in TLR4-positive acute monocytic leukemia THP-1 cells compared to TLR4-negative human embryonic kidney HEK293 cells.

METHODS

We studied the anti-proliferative effects of several HM concentrations on THP-1 and HEK293 cells by evaluating cell viability using the CellTiter-Glo® luminescent assay, assessing the TLR4 expression level, determining the apoptotic status, and analyzing the cell cycle distribution using flow cytometry. Apoptotic pathways were investigated using mitochondrial transition pore opening, caspase activity assays and immunoblot technology.

RESULTS

Low HM concentrations did not affect THP-1 cell viability, but high HM concentrations (62.5-500 μg/mL) did decrease THP-1 cell viability and induced G0/G1 phase cell cycle arrest. Only at the highest concentration (500 μg/mL), HM slightly increased the TLR4 expression on the THP-1 cell surface, concomitantly upregulated TLR4 whole protein and gene expression, and induced apoptosis in THP-1 cells via activation of the extrinsic and intrinsic pathways. No change of apoptotic status was noticed in TLR4-negative HEK293 cells, although HM decreased HEK293 cell viability and induced cell growth arrest in the G2 phase.

CONCLUSION

HM exerts distinct anti-proliferative effects on human acute monocytic leukemia and embryonic kidney cells mainly through cell cycle interference in a TLR4-independent manner and through apoptosis induction in a TLR4-dependent manner, as observed in only the THP-1 cells.

Oral feeding with probiotic Lactobacillus rhamnosus attenuates cigarette smoke-induced COPD in C57Bl/6 mice: Relevance to inflammatory markers in human bronchial epithelial cells

COPD is a prevalent lung disease with significant impacts on public health. Affected airways exhibit pulmonary neutrophilia and consequent secretion of pro-inflammatory cytokines and proteases, which result in lung emphysema. Probiotics act as nonspecific modulators of the innate immune system that improve several inflammatory responses. To investigate the effect of Lactobacillus rhamnosus (Lr) on cigarette smoke (CS)-induced COPD C57Bl/6 mice were treated with Lr during the week before COPD induction and three times/week until euthanasia. For in vitro assays, murine bronchial epithelial cells as well as human bronchial epithelial cells exposed to cigarette smoke extract during 24 hours were treated with Lr 1 hour before CSE addition. Lr treatment attenuated the inflammatory response both in the airways and lung parenchyma, reducing inflammatory cells infiltration and the production of pro-inflammatory cytokines and chemokines. Also, Lr-treated mice presented with lower metalloproteases in lung tissue and lung remodeling. In parallel to the reduction in the expression of TLR2, TLR4, TLR9, STAT3, and NF-κB in lung tissue, Lr increased the levels of IL-10 as well as SOCS3 and TIMP1/2, indicating the induction of an anti-inflammatory environment. Similarly, murine bronchial epithelial cells as well as human bronchial epithelial cells (BEAS) exposed to CSE produced pro-inflammatory cytokines and chemokines, which were inhibited by Lr treatment in association with the production of anti-inflammatory molecules. Moreover, the presence of Lr also modulated the expression of COPD-associated transcription found into BALF of COPD mice group, i.e., Lr downregulated expression of NF-κB and STAT3, and inversely upregulated increased expression of SOCS3. Thus, our findings indicate that Lr modulates the balance between pro- and anti-inflammatory cytokines in human bronchial epithelial cells upon CS exposure and it can be a useful tool to improve the lung inflammatory response associated with COPD.

Role of HSP60/HSP10 in Lung Cancer: Simple Biomarkers or Leading Actors?

Cancers are one of the major challenges faced by modern medicine both because of their impact in terms of the amount of cases and of the ineffectiveness of therapies used today. A concrete support to the fight against them can be found in the analysis and understanding of the molecular mechanisms involving molecular chaperones. In particular, HSP60 and HSP10 seem to play an important role in carcinogenesis, supporting tumours in their proliferation, survival, and metastasis. Efforts must be directed toward finding ways to eliminate or block this "mistaken" chaperone. Therefore, the scientific community must develop therapeutic strategies that consider HSP60 and HSP10 as the possible target of an anti-tumoural treatment and not only as diagnostic biomarkers, since they contribute to the evolution of pre-cancerous respiratory pathologies in lung tumours. HSP60 acts at the mitochondrial, cytoplasmic, and extracellular levels in the development of cancer pathologies. The molecular mechanisms in which these chaperones are involved concern cell survival, the restoration of a condition of absence of replicative senescence, the promotion of pro-inflammatory environments, and an increase in the ability to form metastases. In this review, we will also present examples of interactions between HSP60 and HSP10 and different molecules and ways to exploit this knowledge in anticancer therapies for lung tumours. In order to improve not only chances for an earlier diagnosis but also treatments for patients suffering from this type of disease, chaperones must be considered as key agents in carcinogenesis and primary targets in therapeutics.

Activation of NLRP3 inflammasome by lymphocytic microparticles via TLR4 pathway contributes to airway inflammation

The presence of elevated T lymphocytic microparticles (TLMPs) during respiratory illness is associated with airway and lung inflammation and epithelial injuries. Although inflammasome and IL-1β signaling are crucial in airway inflammation, little was known about their regulatory mechanism. We hypothesized that TLMPs trigger inflammasome activation and IL-1β production in bronchial and alveolar epithelial cells to induce airway and lung inflammation. In this study, TLMPs induced IL-1β and IL-18 secretion through NLRP3 inflammasome activation and upregulated TLR4 mRNA and protein expression in alveolar (A549) and human airway epithelial (16HBE) cells. Pretreatment with CLI-095, a specific inhibitor of TLR4 signaling, dramatically diminished the TLMP-induced release of IL-1β and IL-18 by inhibiting the formation of NLRP3/ASC/pro-caspase-1 inflammasome in a dose-dependent manner. The TLMP-induced autophagy inhibition in epithelial cells was dependent on the PI3K/Akt signaling pathway, which significantly increased NLRP3 expression and enhanced TLMP-induced inflammation. TLR4, IL-1β, and IL-18 proteins harbored in TLMPs were nonessential for the pro-inflammatory effect. In conclusion, TLMPs induce bronchial and alveolar epithelial cell secretion of IL-1β and IL-18 cytokines by activating the TLR4 and PI3K/Akt signaling pathways and inhibiting autophagy. These effects lead to NLRP3 inflammasome formation and accumulation. TLMPs may be regarded as deleterious markers of airway and lung damage in respiratory diseases.

The lung microbiome: clinical and therapeutic implications

The human respiratory tract, usually considered sterile, is currently being investigated for human-associated microbial communities. According to Dickson's conceptual model, the lung microbiota (LMt) is a dynamic ecosystem, whose composition, in healthy lungs, is likely to reflect microbial migration, reproduction, and elimination. However, which microbial genera constitutes a "healthy microbiome" per se remains hotly debated. It is now widely accepted that a bi-directional gut-lung axis connects the intestinal with the pulmonary microbiota and that the diet could have a role in modulating both microbiotas as in health as in pathological status. The LMt is altered in numerous respiratory disorders such as obstructive airway diseases, interstitial lung diseases, infections, and lung cancer. Some authors hypothesize that the use of specific bacterial strains, termed "probiotics," with positive effects on the host immunity and/or against pathogens, could have beneficial effects in the treatment of intestinal disorders and pulmonary diseases. In this manuscript, we have reviewed the literature available on the LMt to delineate and discuss the potential relationship between composition alterations of LMt and lung diseases. Finally, we have reported some meaningful clinical studies that used integrated probiotics' treatments to contrast some lung-correlated disorders.

Bacterial load and inflammatory response in sputum of alpha-1 antitrypsin deficiency patients with COPD

Background

Airway inflammation may drive the progression of chronic obstructive pulmonary disease (COPD) associated with alpha-1 antitrypsin deficiency (AATD), but the relationship between airway microbiota and inflammation has not been investigated.

Methods

We studied 21 non-treated AATD (AATD-noT) patients, 20 AATD-COPD patients under augmentation therapy (AATD-AT), 20 cigarette smoke-associated COPD patients, 20 control healthy smokers (CS) and 21 non-smokers (CON) with normal lung function. We quantified sputum inflammatory cells and inflammatory markers (IL-27, CCL3, CCL5, CXCL8, LTB₄, MPO) by ELISA, total bacterial load (16S) and pathogenic bacteria by qRT-PCR.

Results

AATD-AT patients were younger but had similar spirometric and DLCO values compared to cigarette smoke-associated COPD, despite a lower burden of smoking history. Compared to cigarette smoke-associated COPD, AATD-noT and AATD-AT patients had lower sputum neutrophil levels (p=0.0446, p=0.0135), total bacterial load (16S) (p=0.0081, p=0.0223), M. catarrhalis (p=0.0115, p=0.0127) and S. pneumoniae (p=0.0013, p=0.0001). Sputum IL-27 was significantly elevated in CS and cigarette smoke-associated COPD. AATD-AT, but not AATD-noT patients, had IL-27 sputum levels (pg/ml) significantly lower than COPD (p=0.0297) and these positively correlated with FEV₁% predicted values (r=0.578, p=0.0307).

Conclusions

Compared to cigarette smoke-associated COPD, AATD-AT (COPD) patients have a distinct airway inflammatory and microbiological profile. The decreased sputum bacterial load and IL-27 levels in AATD-AT patients suggests that augmentation therapy play a role in these changes.

Inflammatory endotypes in COPD

Chronic obstructive pulmonary disease (COPD) is a major global health problem that is poorly treated by current therapies as it has proved difficult to treat the underlying inflammation, which is largely corticosteroid-resistant in most patients. Although rare genetic endotypes of COPD have been recognized, despite the clinical heterogeneity of COPD, it has proved difficult to identify distinct inflammatory endotypes. Most patients have increased neutrophils and macrophages in sputum, reflecting the increased secretion of neutrophil and monocyte chemotactic mediators in the lungs. However, some patients also have increased eosinophils in sputum and this may be reflected by increased blood eosinophils. Increased blood and sputum eosinophils are associated with more frequent exacerbations and predict a good response to corticosteroids in reducing and treating acute exacerbations. Eosinophilic COPD may represent an overlap with asthma but the mechanism of eosinophilia is uncertain as, although an increase in sputum IL-5 has been detected, anti-IL-5 therapies are not effective in preventing exacerbations. More research is needed to link inflammatory endotypes to clinical manifestations and outcomes in COPD and in particular to predict response to precision medicines.

Effect of Bufei Yishen Granules Combined with Electroacupuncture in Rats with Chronic Obstructive Pulmonary Disease via the Regulation of TLR-4/NF-κB Signaling

BACKGROUND

The combined therapy of Bufei Yishen granules (BY) and electroacupuncture (EA) has shown good effects clinically in treating chronic obstructive pulmonary disease (COPD). The present study aimed to observe the effects of the BY + EA combination in a COPD rat model and dissect the potential mechanisms via Toll-like receptor (TLR) 4/nuclear factor kappa B (NF-κB) signaling.

METHODS

The COPD rats were treated with normal saline, aminophylline, Bufei Yishen granules, electroacupuncture, or Bufei Yishen granules combined with electroacupuncture. The pulmonary function; lung tissue histology; levels of inflammatory factors; expression levels of TLR-4, inhibitor of nuclear factor kappa B (IκB), and NF-κB; and activation of NF-κB in the lung tissues were evaluated.

RESULTS

Pulmonary function was markedly decreased in the COPD rats, and the lung tissue histology of the COPD rats showed severe pathological changes. The pulmonary function and lung tissue morphology in the treatment groups (APL, BY, EA, and BY + EA) were improved. The increased levels of the inflammatory cytokines interleukin (IL)-1β and IL-6 indicated a chronic inflammatory state in the COPD rats. In the BY, EA, and BY + EA groups, the levels of IL-1β and IL-6 were decreased, especially in the BY + EA group. In addition, the mRNA and protein expression levels of TLR-4, IκB, and NF-κB were obviously downregulated in the BY and BY + EA groups; and the NF-κB p65 activation was significantly decreased in the BY, EA, and BY + EA groups.

CONCLUSIONS

Bufei Yishen granules and electroacupuncture have curative effects in COPD rats, and the combination therapy of Bufei Yishen granules and electroacupuncture is superior. The TLR-4/NF-κB pathway may be involved in the potential mechanisms by which Bufei Yishen granules and electroacupuncture reduce inflammation.

Pulmonary Diseases and Ageing

Chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis are regarded as a diseases of accelerated lung ageing and show all of the hallmarks of ageing, including telomere shortening, cellular senescence, activation of PI3 kinase-mTOR signaling, impaired autophagy, mitochondrial dysfunction, stem cell exhaustion, epigenetic changes, abnormal microRNA profiles, immunosenescence and a low grade chronic inflammation due to senescence-associated secretory phenotype (SASP). Many of these ageing mechanisms are driven by exogenous and endogenous oxidative stress. There is also a reduction in anti-ageing molecules, such as sirtuins and Klotho, which further accelerate the ageing process. Understanding these molecular mechanisms has identified several novel therapeutic targets and several drugs and dietary interventions are now in development to treat chronic lung disease.