The elevated CXCL5 levels in circulation are associated with lung function decline in COPD patients and cigarette smoking-induced mouse model of 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.

Microplastics dysregulate innate immunity in the SARS-CoV-2 infected lung

Introduction

Global microplastic (MP) pollution is now well recognized, with humans and animals consuming and inhaling MPs on a daily basis, with a growing body of concern surrounding the potential impacts on human health.

Methods

Using a mouse model of mild COVID-19, we describe herein the effects of azide-free 1 μm polystyrene MP beads, co-delivered into lungs with a SARS-CoV-2 omicron BA.5 inoculum. The effect of MPs on the host response to SARS-CoV-2 infection was analysed using histopathology and RNA-Seq at 2 and 6 days post-infection (dpi).

Results

Although infection reduced clearance of MPs from the lung, virus titres and viral RNA levels were not significantly affected by MPs, and overt MP-associated clinical or histopathological changes were not observed. However, RNA-Seq of infected lungs revealed that MP exposure suppressed innate immune responses at 2 dpi and increased pro-inflammatory signatures at 6 dpi. The cytokine profile at 6 dpi showed a significant correlation with the 'cytokine release syndrome' signature observed in some COVID-19 patients.

Discussion

The findings are consistent with the recent finding that MPs can inhibit phagocytosis of apoptotic cells via binding of Tim4. They also add to a growing body of literature suggesting that MPs can dysregulate inflammatory processes in specific disease settings.

Smoking changes adaptive immunity with persistent effects

Individuals differ widely in their immune responses, with age, sex and genetic factors having major roles in this inherent variability1-6. However, the variables that drive such differences in cytokine secretion-a crucial component of the host response to immune challenges-remain poorly defined. Here we investigated 136 variables and identified smoking, cytomegalovirus latent infection and body mass index as major contributors to variability in cytokine response, with effects of comparable magnitudes with age, sex and genetics. We find that smoking influences both innate and adaptive immune responses. Notably, its effect on innate responses is quickly lost after smoking cessation and is specifically associated with plasma levels of CEACAM6, whereas its effect on adaptive responses persists long after individuals quit smoking and is associated with epigenetic memory. This is supported by the association of the past smoking effect on cytokine responses with DNA methylation at specific signal trans-activators and regulators of metabolism. Our findings identify three novel variables associated with cytokine secretion variability and reveal roles for smoking in the short- and long-term regulation of immune responses. These results have potential clinical implications for the risk of developing infections, cancers or autoimmune diseases.

Expression of Inflammatory Genes in Murine Lungs in a Model of Experimental Pulmonary Hypertension: Effects of an Antibody-Based Targeted Delivery of Interleukin-9

BACKGROUND

Pathogenesis of pulmonary hypertension (PH) is a multifactorial process driven by inflammation and pulmonary vascular remodeling. To target these two aspects of PH, we recently tested a novel treatment: Interleukin-9 (IL9) fused to F8, an antibody that binds to the extra-domain A of fibronectin (EDA+ Fn). As EDA+ Fn is not found in healthy adult tissue but is expressed during PH, IL9 is delivered specifically to the tissue affected by PH. We found that F8IL9 reduced pulmonary vascular remodeling and attenuated PH compared with sham-treated mice.

PURPOSE

To evaluate possible F8IL9 effects on PH-associated inflammatory processes, we analysed the expression of genes involved in pulmonary immune responses.

METHODS

We applied the monocrotaline (MCT) model of PH in mice (n = 44). Animals were divided into five experimental groups: sham-induced animals without PH (control, n = 4), MCT-induced PH without treatment (PH, n = 8), dual endothelin receptor antagonist treatment (dual ERA, n = 8), F8IL9 treatment (n = 12, 2 formats with n = 6 each), or with KSFIL9 treatment (KSFIL9, n = 12, 2 formats with n = 6 each, KSF: control antibody with irrelevant antigen specificity). After 28 days, a RT-PCR gene expression analysis of inflammatory response (84 genes) was performed in the lung.

RESULTS

Compared with the controls, 19 genes exhibited relevant (+2.5-fold) upregulation in the PH group without treatment. Gene expression levels in F8IL9-treated lung tissue were reduced compared to the PH group without treatment. This was the case especially for CCL20, CXCL5, C-reactive protein, pentraxin related (CRPPR), and Kininogen-1 (KNG1).

CONCLUSION

In accordance with the hypothesis stated above, F8IL9 treatment diminished the upregulation of some genes associated with inflammation in a PH animal model. Therefore, we hypothesize that IL9-based immunocytokine treatment will likely modulate various inflammatory pathways.

Mitochondrial damage-associated molecular patterns in chronic obstructive pulmonary disease: Pathogenetic mechanism and therapeutic target

Chronic obstructive pulmonary disease (COPD) is a common inflammatory airway disease characterized by enhanced inflammation. Recent studies suggest that mitochondrial damage-associated molecular patterns (DAMPs) may play an important role in the regulation of inflammation and are involved in a serial of inflammatory diseases, and they may also be involved in COPD. This review highlights the potential role of mitochondrial DAMPs during COPD pathogenesis and discusses the therapeutic potential of targeting mitochondrial DAMPs and their related signaling pathways and receptors for COPD. Research progress on mitochondrial DAMPs may enhance our understanding of COPD inflammation and provide novel therapeutic targets.

Integrated procedures for accelerating, deepening, and leading genetic inquiry: A first application on human muscle secretome

PURPOSE

Beyond classical procedures, bioinformatic-assisted approaches and computational biology offer unprecedented opportunities for scholars. However, these amazing possibilities still need epistemological criticism, as well as standardized procedures. Especially those topics with a huge body of data may benefit from data science (DS)-assisted methods. Therefore, the current study dealt with the combined expert-assisted and DS-assisted approaches to address the broad field of muscle secretome. We aimed to apply DS tools to fix the literature research, suggest investigation targets with a data-driven approach, predict possible scenarios, and define a workflow.

METHODS

Recognized scholars with expertise on myokines were invited to provide a list of the most important myokines. GeneRecommender, GeneMANIA, HumanNet, and STRING were selected as DS tools. Networks were built on STRING and GeneMANIA. The outcomes of DS tools included the top 5 recommendations. Each expert-led discussion has been then integrated with an DS-led approach to provide further perspectives.

RESULTS

Among the results, 11 molecules had already been described as bona-fide myokines in literature, and 11 molecules were putative myokines. Most of the myokines and the putative myokines recommended by the DS tools were described as present in the cargo of extracellular vesicles.

CONCLUSIONS

Including both supervised and unsupervised learning methods, as well as encompassing algorithms focused on both protein interaction and gene represent a comprehensive approach to tackle complex biomedical topics. DS-assisted methods for reviewing existent evidence, recommending targets of interest, and predicting original scenarios are worth exploring as in silico recommendations to be integrated with experts' ideas for optimizing molecular studies.

Evaluating Novel Protein Phosphatase 2A Activators as Therapeutics for Emphysema

The activity of PP2A (protein phosphatase 2A), a serine-threonine phosphatase, is reduced by chronic cigarette smoke (SM) exposure and α-1 antitrypsin (AAT) deficiency, and chemical activation of PP2A reduces the loss of lung function in SM-exposed mice. However, the previously studied PP2A-activator tricyclic sulfonamide compound DBK-1154 has low stability to oxidative metabolism, resulting in fast clearance and low systemic exposure. Here we compare the utility of a new more stable PP2A activator, ATUX-792, versus DBK-1154 for the treatment of SM-induced emphysema. ATUX-792 was also tested in human bronchial epithelial cells and a mouse model of AAT deficiency, Serpina1a-e-knockout mice. Human bronchial epithelial cells were treated with ATUX-792 or DBK-1154, and cell viability, PP2A activity, and MAP (mitogen-activated protein) kinase phosphorylation status were examined. Wild-type mice received vehicle, DBK-1154, or ATUX-792 orally in the last 2 months of 4 months of SM exposure, and 8-month-old Serpina1a-e-knockout mice received ATUX-792 daily for 4 months. Forced oscillation and expiratory measurements and histology analysis were performed. Treatment with ATUX-792 or DBK-1154 resulted in PP2A activation, reduced MAP kinase phosphorylation, immune cell infiltration, reduced airspace enlargements, and preserved lung function. Using protein arrays and multiplex assays, PP2A activation was observed to reduce AAT-deficient and SM-induced release of CXCL5, CCL17, and CXCL16 into the airways, which coincided with reduced neutrophil lung infiltration. Our study indicates that suppression of the PP2A activity in two models of emphysema could be restored by next-generation PP2A activators to impact lung function.

Animal models and mechanisms of tobacco smoke-induced chronic obstructive pulmonary disease (COPD)

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide, and its global health burden is increasing. COPD is characterized by emphysema, mucus hypersecretion, and persistent lung inflammation, and clinically by chronic airflow obstruction and symptoms of dyspnea, cough, and fatigue in patients. A cluster of pathologies including chronic bronchitis, emphysema, asthma, and cardiovascular disease in the form of hypertension and atherosclerosis variably coexist in COPD patients. Underlying causes for COPD include primarily tobacco use but may also be driven by exposure to air pollutants, biomass burning, and workplace related fumes and chemicals. While no single animal model might mimic all features of human COPD, a wide variety of published models have collectively helped to improve our understanding of disease processes involved in the genesis and persistence of COPD. In this review, the pathogenesis and associated risk factors of COPD are examined in different mammalian models of the disease. Each animal model included in this review is exclusively created by tobacco smoke (TS) exposure. As animal models continue to aid in defining the pathobiological mechanisms of and possible novel therapeutic interventions for COPD, the advantages and disadvantages of each animal model are discussed.

Circadian disruption in lung fibroblasts enhances NF-κB activity to exacerbate neutrophil recruitment

Fibroblasts are stromal cells abundant throughout tissues, including the lungs. Fibroblasts are integral coordinators of immune cell recruitment through chemokine secretion. Circadian rhythms direct the recruitment of immune cells to the lung, which in turn impacts response to infection and survival. Although fibroblasts display robust circadian rhythms, the contribution of the fibroblast molecular clock to lung-specific migration of immune cells and recruitment remains to be established. Mice challenged intranasally with lipopolysaccharide (LPS) at dusk showed increased expression of the pro-inflammatory cytokine IL-1β and chemokine CXCL5 in the lung, which was accompanied by increased neutrophil recruitment. Primary lung fibroblasts with knockdown of the core clock gene Bmal1 and immortalized Bmal1-/- lung fibroblasts also displayed increased Cxcl5 expression under IL-1β stimulation. Conditioned media obtained from IL-1β-stimulated Bmal1-/- immortalized fibroblasts-induced greater neutrophil migration compared with Bmal1+/+ lung fibroblast controls. Phosphorylation of the NF-κB subunit, p65, was enhanced in IL-1β-stimulated Bmal1-/- lung fibroblasts, and pharmacological inhibition of NF-κB attenuated the enhanced CXCL5 production and neutrophil recruitment observed in these cells. Collectively, these results demonstrate that Bmal1 represses NF-κB activity in lung fibroblasts to control chemokine expression and immune cell recruitment during an inflammatory response.

Inhibition of neutrophil elastase prevents cigarette smoke exposure-induced formation of neutrophil extracellular traps and improves lung function in a mouse model of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is an important public health challenge worldwide, and is usually caused by significant exposure to noxious agents, particularly cigarette smoke. Recent studies have revealed that excessive production of neutrophil extracellular traps (NETs) in the airways is associated with disease severity in COPD patients. NETs are extracellular neutrophil-derived structures composed of chromatin fibers decorated with histones and granule proteases including neutrophil elastase (NE). However, the effective prevention of NET formation in COPD remains elusive. Here, we demonstrated that treatment with GW311616A, a potent and selective inhibitor of NE, prevented cigarette smoke extract (CSE)-induced NET formation in human neutrophils by blocking NE nuclear translocation and subsequent chromatin decondensation. Inhibition of NE also abrogated CSE-induced ROS production and migration impairment of neutrophils. Administration of GW311616A in vivo substantially reduced pulmonary generation of NETs while attenuating the key pathological changes in COPD, including airway leukocyte infiltration, mucus-secreting goblet cell hyperplasia, and emphysema-like alveolar destruction in a mouse model of COPD induced by chronic cigarette smoke exposure. Mice treated with GW311616A also showed significant attenuation of neutrophil numbers and percentages and the levels of neutrophil chemotactic factors (LTB4, KC, and CXCL5) and proinflammatory cytokines (IL-1β, and TNF-α) in bronchoalveolar lavage fluid compared to mice treated with cigarette smoke exposure only. Furthermore, GW311616A treatment considerably improved lung function in the COPD mouse model, including preventing the decline of FEV₁₀₀/FVC and delta PEF as well as inhibiting the increase in FRC, TLC, and FRC/TLC. Overall, our study suggests that NE plays a critical role in cigarette smoke-induced NET formation by neutrophils and that inhibition of NE is a promising strategy to suppress NET-mediated pathophysiological changes in COPD.

Dopamine relieves inflammatory responses through the D2 receptor after electroacupuncture at ST36 in a mouse model of chronic obstructive pulmonary disease

OBJECTIVE

To detect the role of dopamine in the anti-inflammatory effect of electroacupuncture (EA) at ST36 in a mouse model of chronic obstructive pulmonary disease (COPD).

METHODS

Twenty-eight male BALB/c mice were randomly divided into the control group, model group, sham EA (sham) group or ST36 EA (ST36) group in a 1:1:1:1 ratio (n = 7 each). The COPD mouse model was established through cigarette smoke (CS) exposure for 12 weeks. During the last 2 weeks, EA was applied at a sham point location or ST36 before CS exposure. Lung function, histopathological changes, inflammatory cell counts in bronchoalveolar lavage fluid (BALF), inflammatory cytokines in BALF, plasma, lung tissue homogenate (LTH), and plasma dopamine levels were detected in the different groups. Furthermore, the role of different dopamine receptors was explored through intraperitoneal injections of non-specific dopamine receptor antagonist chlorpromazine, specific dopamine D1 receptor antagonist SCH 23390 and specific dopamine D2 receptor antagonist eticlopride hydrochloride prior to ST36 EA and CS exposure.

RESULTS

EA at ST36 improved lung function, alleviated lung and systemic inflammatory responses by reducing inflammatory cells and cytokines including tumor necrosis factor (TNF)-α, interleukin (IL)-8 and IL-1β in BALF, plasma and lung tissue in this COPD mouse model. Plasma dopamine was greatly increased after EA at ST36, negatively correlated with lung histological lesions and inflammatory cytokine levels, and positively correlated with mice body weight and lung function indicators. Chlorpromazine and eticlopride hydrochloride inhibited the anti-inflammatory effect of EA at ST36, while SCH 23390 showed no neutralizing effect.

CONCLUSION

EA at ST36 could alleviate inflammation in this mouse model of COPD through the dopamine D2 receptor pathway.

Zhuye Shigao Decoction Combined with Qingqi Huatan Pills in Alleviating the Acute Exacerbation of Chronic Obstructive Pulmonary Disease (Phlegm-Heat Stagnating in the Lungs) via the IL-6-Mediated JAK1/STAT3 Signaling Pathway

Chronic obstructive pulmonary disease (COPD) is a chronic disease with a long course which is often induced by an acute exacerbation of the disease by a respiratory tract infection. We aimed to explore the effect of Zhuye Shigao Decoction combined with Qingqi Huatan Pills on the regulation of the interleukin (IL)-6-mediated JAK1/STAT3 signaling pathway in rats with an acute exacerbation of COPD (phlegm-heat stagnating in the lungs). A model of COPD rats with lung phlegm-heat stagnation was established by smoking and intratracheal injection of lipopolysaccharide (LPS). The rats were randomly divided into eight groups: normal control, model control, three doses of herbs group, and three doses of herbs + itacitinib groups. The lung function indexes were measured by using a lung function tester, and changes in pathological features of all groups were observed by hematoxylin-eosin (HE) staining. The mRNA expression and protein expression levels in lung tissues were determined by real-time quantitative polymerase chain reaction (RT-qPCR), western blot, and immunohistochemical assay, respectively. Following treatment, IL-6 expression in lung tissues was significantly reduced compared with the model group. The results demonstrated that the medication was effective in alleviating the persistent airflow limitation and pathological features in COPD rats. Expression of JAK1/STAT3 in lung tissues was remarkably decreased. The JAK1/STAT3 pathway was inhibited, while SOCS3 expression was upregulated in the drug-treated groups compared with model control. However, after the addition of itacitinib (JAK1 inhibitor), the efficacy in each group was evidently impaired compared with herbs alone. Taken together, Zhuye Shigao Decoction combined with Qingqi Huatan Pills could improve the persistent airflow limitation and reduce lung inflammation and pathological changes of COPD possibly by regulating the expression of the IL-6-mediated JAK1/STAT3 pathway.

Epithelial Ablation of Miro1/Rhot1 GTPase Augments Lung Inflammation by Cigarette Smoke

Mitochondrial quality control is sustained by Miro1 (Rhot1), a calcium-binding membrane-anchored GTPase during mitophagy. The exact mechanism that operates the interaction of Miro1 with mitophagy machinery and their role in cigarette smoke (CS)-induced mitochondrial dysfunction that often results in lung inflammation is unclear. We hypothesized that Miro1 plays an important role in regulating mitophagy machinery and the resulting lung inflammation by CS exposure to mice. The lung epithelial Rhot1^fl/fl (WT) and Rhot1^CreCC10 mice were exposed to mainstream CS for 3 days (acute) and 4 months (chronic). Acute CS exposure showed a notable increase in the total inflammatory cells, macrophages, and neutrophils that are associated with inflammatory mediators. Chronic exposure showed increased infiltration of neutrophils versus air controls. The effects of acute and chronic CS exposure were augmented in the Rhot1^CreCC10 group, indicating that epithelial Miro1 ablation led to the augmentation of inflammatory cell infiltration with alteration in the inflammatory mediators. Thus, Rhot1/Miro1 plays an important role in regulating CS-induced lung inflammatory responses with implications in mitochondrial quality control.

Complement factor H deficiency combined with smoking promotes retinal degeneration in a novel mouse model

Age-related macular degeneration is the leading cause of blindness in the elderly. The Y402H polymorphism in complement factor H promotes disease-like pathogenesis, and a Cfh^+/- murine model can replicate this phenotype, but only after two years. We reasoned that by combining CFH deficiency with cigarette smoke exposure, we might be able to accelerate disease progression to facilitate preclinical research in this disease. Wild-type and Cfh^+/- mice were exposed to nose-only cigarette smoke for three months. Retinal tissue morphology and visual function were evaluated by optical coherence tomography, fundus photography and autofluorescence, and electroretinogram. Retinal pigment epithelial cell phenotype and ultrastructure were evaluated by immunofluorescence staining and transmission electron microscopy. Cfh^+/- smoking mice showed a dome-like protruding lesion at the ellipsoid zone (drusen-like deposition), many retinal hyper-autofluorescence spots, and a marked decrease in A- and B-wave amplitudes. Compared with non-smoking mice, wild-type and Cfh^+/- smoking mice showed sub-retinal pigment epithelium complement protein 3 deposition, activation of microglia, metabolic waste accumulation, and impairment of tight junctions. Microglia cells migrated into the photoreceptor outer segment layer in Cfh^+/- smoking mice showed increased activation. Our results suggest that exposing Cfh^+/- mice to smoking leads to earlier onset of age-related macular degeneration than in other animal models, which may facilitate preclinical research into the pathophysiology and treatment of this disease.

Maternal smoking-induced lung injuries in dams and offspring via inflammatory cytokines

Maternal smoking during pregnancy can induce permanent changes in neonatal inflammation, which will result in lifelong implications. An original study of data from GSE96978, composed of 2 subseries (GSE96976 and GSE96977), investigated genome-wide changes in ELT cells, the lungs of mouse dams and their juvenile offspring and focused on finding an in vitro alternative as a human tissue-based replacement for the use of animals. Therefore, the study only analyzed the similarities of GO terms between ELT cells and dams. However, the relationship between differentially expressed genes (DEGs) in dams and offspring was not investigated. The present study aimed to identify the key molecules involved in maternal smoking-induced dam and offspring lung injuries. Data from GSE96977 were downloaded from Gene Expression Omnibus (GEO) data sets. In our study, differentially expressed genes (DEGs) in dams and offspring were reanalyzed using the limma package. The results of Gene Set Enrichment Analysis (GSEA) showed that the DEGs in the lungs of dams were significantly enriched in immune-related functions and those in the lungs of offspring were enriched in cell growth. Furthermore, a total of 90 DEGs shared in the dam and offspring datasets were screened out. In addition, most of these DEGs were enriched in cytokine and cytokine receptor interaction KEGG pathways. Furthermore, protein-protein interaction (PPI) network analysis screened out 4 core genes in cluster 1. In addition, the miRNAs related to these core genes were predicted, and mmu-miR-1903 was screened out. Taken together, our data indicate that inflammatory responses may play an important role in maternal smoking induced lung injuries in dams and offspring. Furthermore, mmu-miR-1903 is a potential epigenetic biomarker of lung inflammation in the offspring of dams who smoked during pregnancy. In conclusion, by screening shared differential genes, we only need to detect maternal genes to predict maternal smoking-induced lung injuries in offspring.

p300/Sp1-Mediated High Expression of p16 Promotes Endothelial Progenitor Cell Senescence Leading to the Occurrence of Chronic Obstructive Pulmonary Disease

OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is a common chronic disease and develops rapidly into a grave public health problem worldwide. However, what exactly causes the occurrence of COPD remains largely unclear. Here, we are trying to explore whether the high expression of p16 mediated by p300/Sp1 can cause chronic obstructive pulmonary disease through promoting the senescence of endothelial progenitor cells (EPCs).

METHODS

Peripheral blood EPCs were isolated from nonsmoking non-COPD, smoking non-COPD, and smoking COPD patients. The expressions of p16, p300, and senescence-related genes were detected by RT-PCR and Western Blot. Then, we knocked down or overexpressed Sp1 and p300 and used the ChIP assay to detect the histone H4 acetylation level in the promoter region of p16, CCK8 to detect cell proliferation, flow cytometry to detect the cell cycle, and β-galactosidase staining to count the proportion of senescent cells.

RESULTS

The high expression of p16 was found in peripheral blood EPCs of COPD patients; the cigarette smoke extract (CSE) led to the increase of p16. The high expression of p16 in EPCs promoted cell cycle arrest and apoptosis. The CSE-mediated high expression of p16 promoted cell senescence. The expression of p300 was increased in peripheral blood EPCs of COPD patients. Moreover, p300/Sp1 enhanced the histone H4 acetylation level in the promoter region of p16, thereby mediating the senescence of EPCs. And knockdown of p300/Sp1 could rescue CSE-mediated cell senescence.

CONCLUSION

p300/Sp1 enhanced the histone H4 acetylation level in the p16 promoter region to mediate the senescence of EPCs.

Knockout of Formyl Peptide Receptor-1 Attenuates Cigarette Smoke-Induced Airway Inflammation in Mice

Objective: The formyl peptide receptor-1 (FPR-1) has been reported to be implicated in the regulation of inflammatory disorders, while its role in cigarette smoke (CS)-induced airway inflammation has not been fully explained. In this study, we investigated the role of FPR-1 in CS-induced airway inflammation and the possible mechanism through gene knockout (KO) technology and transcriptional study. Methods: FPR-1 KO or wild-type C57BL/6 mice were exposed to mainstream CS to establish an airway inflammation model. Cell counts and pro-inflammatory cytokines were measured in bronchoalveolar lavage fluid (BALF). Lung tissues were collected for histological examination, polymerase chain reaction, Western blot, transcriptomic gene study, and related bioinformatics analysis. Results: CS exposure induced significant histological inflammatory changes, increased neutrophils, and pro-inflammatory cytokines in the BALF of wild-type mice, which were all attenuated by KO of FPR-1. The transcriptomic gene study showed a total of 198 up-regulated genes and 282 down-regulated genes in mouse lungs. Bioinformatics analysis including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) suggested these differentiated expressed genes were significantly related to the immune, chemotaxis responses, and cross-talked with a complicated network of signaling pathways including NF-κB. Western blot validated that KO of FPR-1 inhibited CS-induced NF-κB activation. Conclusion: Knockout of FPR-1 significantly ameliorates CS-induced airway inflammation in mice, possibly via its related immune-chemotaxis responses and inhibition of NF-κB activation.

CFTR Correctors and Antioxidants Partially Normalize Lipid Imbalance but not Abnormal Basal Inflammatory Cytokine Profile in CF Bronchial Epithelial Cells

A deficiency in cystic fibrosis transmembrane conductance regulator (CFTR) function in CF leads to chronic lung disease. CF is associated with abnormalities in fatty acids, ceramides, and cholesterol, their relationship with CF lung pathology is not completely understood. Therefore, we examined the impact of CFTR deficiency on lipid metabolism and pro-inflammatory signaling in airway epithelium using mass spectrometric, protein array. We observed a striking imbalance in fatty acid and ceramide metabolism, associated with chronic oxidative stress under basal conditions in CF mouse lung and well-differentiated bronchial epithelial cell cultures of CFTR knock out pig and CF patients. Cell-autonomous features of all three CF models included high ratios of ω-6- to ω-3-polyunsaturated fatty acids and of long- to very long-chain ceramide species (LCC/VLCC), reduced levels of total ceramides and ceramide precursors. In addition to the retinoic acid analog fenretinide, the anti-oxidants glutathione (GSH) and deferoxamine partially corrected the lipid profile indicating that oxidative stress may promote the lipid abnormalities. CFTR-targeted modulators reduced the lipid imbalance and oxidative stress, confirming the CFTR dependence of lipid ratios. However, despite functional correction of CF cells up to 60% of non-CF in Ussing chamber experiments, a 72-h triple compound treatment (elexacaftor/tezacaftor/ivacaftor surrogate) did not completely normalize lipid imbalance or oxidative stress. Protein array analysis revealed differential expression and shedding of cytokines and growth factors from CF epithelial cells compared to non-CF cells, consistent with sterile inflammation and tissue remodeling under basal conditions, including enhanced secretion of the neutrophil activator CXCL5, and the T-cell activator CCL17. However, treatment with antioxidants or CFTR modulators that mimic the approved combination therapies, ivacaftor/lumacaftor and ivacaftor/tezacaftor/elexacaftor, did not effectively suppress the inflammatory phenotype. We propose that CFTR deficiency causes oxidative stress in CF airway epithelium, affecting multiple bioactive lipid metabolic pathways, which likely play a role in CF lung disease progression. A combination of anti-oxidant, anti-inflammatory and CFTR targeted therapeutics may be required for full correction of the CF phenotype.

Mitoquinone ameliorates cigarette smoke-induced airway inflammation and mucus hypersecretion in mice

BACKGROUND

Cigarette smoking, which induces airway inflammation and mucus hypersecretion, is a major risk factor for the development of cigarette smoke (CS)-induced airway disorders. In this study, we investigated the effects and mechanisms of mitoquinone (MitoQ), a mitochondria-targeted antioxidant, on CS-induced airway inflammation and mucus hypersecretion in mice.

METHODS

C57BL/6J mice were exposed to CS for 75 min twice daily, 5 days per week for 4 weeks. MitoQ (2.5, 5 mg/kg/day) was administered intraperitoneally 1 h before CS exposure. Bronchoalveolar lavage fluid (BALF) was obtained for cell counting and determination of pro-inflammatory cytokine levels. Lung tissue was collected for histological examination; Western blotting was used to measure levels of Mfn2, Drp1, cytochrome c, NF-κB p65, and IκBα.

RESULTS

Pretreatment with MitoQ significantly attenuated CS-induced thickening of the airway epithelium, peribronchial inflammatory cell infiltration, goblet cell hyperplasia and Muc5ac staining. The numbers of total cells, neutrophils and macrophages, as well as levels of TNF-α and IL-6 in BALF were remarkably decreased by MitoQ in a dose-dependent manner. MitoQ attenuated oxidative stress by preventing the CS-induced increase in malondialdehyde level and decrease in superoxide dismutase activity and GSH/GSSG ratio. MitoQ decreased the expression of mitochondrial fission protein Drp1 and increased that of mitochondrial fusion protein Mfn2, as well as reduced cytochrome c release into the cytosol. Furthermore, MitoQ suppressed IκBα degradation and NF-κB p65 nuclear translocation.

CONCLUSIONS

MitoQ attenuates inflammation, mucus hypersecretion, and oxidative stress induced by CS. It may exert these effects in part by modulating mitochondrial function and the NF-κB signal pathway.

Emerging Role of Mitophagy in Inflammatory Diseases: Cellular and Molecular Episodes

Mitochondria are the crucial regulators for the major source of ATP for different cellular events. Due to damage episodes, mitochondria have been established for a plethora ofalarming signals of stress that lead to cellular deterioration, thereby causing programmed cell death. Defects in mitochondria play a key role in arbitrating pathophysiological machinery with recent evince delineating a constructive role in mitophagy mediated mitochondrial injury. Mitophagy has been known for the eradication of damaged mitochondria via the autophagy process. Mitophagy has been investigated as an evolutionarily conserved mechanism for mitochondrial quality control and homeostasis. Impaired mitophagy has been critically linked with the pathogenesis of inflammatory diseases. Nevertheless, the exact mechanism is not quite revealed, and it is still debatable. The purpose of this review was to investigate the possible role of mitophagy and its associated mechanism in inflammation-mediated diseases at both the cellular and molecular levels.

Resolution of Pulmonary Inflammation Induced by Carbon Nanotubes and Fullerenes in Mice: Role of Macrophage Polarization

Pulmonary exposure to certain engineered nanomaterials (ENMs) causes chronic lesions like fibrosis and cancer in animal models as a result of unresolved inflammation. Resolution of inflammation involves the time-dependent biosynthesis of lipid mediators (LMs)-in particular, specialized pro-resolving mediators (SPMs). To understand how ENM-induced pulmonary inflammation is resolved, we analyzed the inflammatory and pro-resolving responses to fibrogenic multi-walled carbon nanotubes (MWCNTs, Mitsui-7) and low-toxicity fullerenes (fullerene C60, C60F). Pharyngeal aspiration of MWCNTs at 40 μg/mouse or C60F at a dose above 640 μg/mouse elicited pulmonary effects in B6C3F1 mice. Both ENMs stimulated acute inflammation, predominated by neutrophils, in the lung at day 1, which transitioned to histiocytic inflammation by day 7. By day 28, the lesion in MWCNT-exposed mice progressed to fibrotic granulomas, whereas it remained as alveolar histiocytosis in C60F-exposed mice. Flow cytometric profiling of whole lung lavage (WLL) cells revealed that neutrophil recruitment was the greatest at day 1 and declined to 36.6% of that level in MWCNT- and 16.8% in C60F-treated mice by day 7, and to basal levels by day 28, suggesting a rapid initiation phase and an extended resolution phase. Both ENMs induced high levels of proinflammatory leukotriene B4 (LTB4) and prostaglandin E2 (PGE2) with peaks at day 1, and high levels of SPMs resolvin D1 (RvD1) and E1 (RvE1) with peaks at day 7. MWCNTs and C60F induced time-dependent polarization of M1 macrophages with a peak at day 1 and subsequently of M2 macrophages with a peak at day 7 in the lung, accompanied by elevated levels of type 1 or type 2 cytokines, respectively. M1 macrophages exhibited preferential induction of arachidonate 5-lipoxygenase activating protein (ALOX5AP), whereas M2 macrophages had a high level expression of arachidonate 15-lipoxygenase (ALOX15). Polarization of macrophages in vitro differentially induced ALOX5AP in M1 macrophages or ALOX15 in M2 macrophages resulting in increased preferential biosynthesis of proinflammatory LMs or SPMs. MWCNTs increased the M1- or M2-specific production of LMs accordingly. These findings support a mechanism by which persistent ENM-induced neutrophilic inflammation is actively resolved through time-dependent polarization of macrophages and enhanced biosynthesis of specialized LMs via distinct ALOX pathways.