Fibrosis Airway Research Articles

Different exposure modes of PM2.5 induces bronchial asthma and fibrosis in male rats through macrophage activation and immune imbalance induced by TIPE2 methylation

Exposure to PM2.5 can aggravate the occurrence and development of bronchial asthma and fibrosis. Here, we investigated the differences in bronchial injury caused by different exposure modes of PM2.5 (high concentration intermittent exposure and low concentration continuous exposure), and the mechanism of macrophage activation and respiratory immune imbalance induced by PM2.5, leading to bronchial asthma and airway fibrosis using animal and cell models. A "PM2.5 real-time online concentrated animal whole-body exposure system" was used to conduct PM2.5 respiratory exposure of Wistar rats for 12 weeks, which can enhance oxidative stress in rat bronchus, activate epithelial cells and macrophages, release chemokines, recruit inflammatory cells, release inflammatory factors and extracellular matrix, promote bronchial mucus hypersecretion, inhibit the expression of epithelial cytoskeletal proteins, destroy airway barrier, and induce asthma. Furthermore, PM2.5 induced M2 polarization in lung bronchial macrophages through JAK/STAT and PI3K/Akt signaling pathways, and compared with low concentration continuous exposure, high concentration intermittent exposure of PM2.5 could regulate significantly higher expression of TIPE2 protein through promoter methylation of TIPE2 DNA, thereby activating PI3K/Akt signaling pathway and more effectively inducing M2 polarization of macrophages. Additionally, activated macrophages release IL-23, and activated epithelial cells and macrophages released TGF-β1, which promoted the differentiation of Th17 cells, triggered the Th17 dominant immune response, and activated the TGF-β1/Smad2 signaling pathway, finally causing bronchial fibrosis. Moreover, when the total amount of PM2.5 exposure was equal, high concentration-intermittent exposure was more serious than low concentration-continuous exposure. In vitro experiments, the co-culture models of PM2.5 with BEAS-2B, WL-38 and rat primary alveolar macrophages further confirmed that PM2.5 could induce the macrophage activation through oxidative stress and TIPE2 DNA methylation, and activate the TGF-β1/Smad2 signaling pathway, leading to the occurrence of bronchial fibrosis.

Deletion of sphingosine kinase 2 attenuates cigarette smoke-mediated chronic obstructive pulmonary disease-like symptoms by reducing lung inflammation.

Cigarette smoke (CS) is the leading cause of chronic obstructive pulmonary disease (COPD), which is characterized by chronic bronchial inflammation and emphysema. Growing evidence supports the hypothesis that dysfunctional cystic fibrosis transmembrane conductance regulator (CFTR) is critically involved in the pathogenesis of CS-mediated COPD. However, the underlying mechanism remains unclear. Here, we report that supressed CFTR expression is strongly associated with abnormal phospholipid metabolism and increased pulmonary inflammation. In a CS-exposed mouse model with COPD-like symptoms, we found that pulmonary expression of sphingosine kinase 2 (SphK2) and sphingosine-1-phosphate (S1P) secretion were significantly upregulated. Therefore, we constructed a SphK2 gene knockout (SphK2-/-) mouse. After CS exposure for six months, histological lung section staining showed disorganized alveolar structure, increased pulmonary fibrosis, and emphysema-like symptoms in wild-type (WT) mice, which were less pronounced in SphK2-/- mice. Further, SphK2 deficiency also decreased CS-induced pulmonary inflammation, which was reflected by a remarkable reduction in pulmonary infiltration of CD45+CD11b+ neutrophils subpopulation and low levels of IL-6 and IL-33 in bronchial alveolar lavage fluid. However, treatment with S1P receptor agonist suppressed CFTR expression and increased Nf-κB-p65 expression and its nuclear translocation in CS-exposed SphK2-/-mice, which also aggravated small airways fibrosis and pulmonary inflammation. In contrast, inhibition of S1P signaling with the S1P receptor analogue FTY720 rescued CFTR expression, suppressed Nf-κB-p65 expression and nuclear translocation, and alleviated pulmonary fibrosis and inflammation after CS exposure. Our results demonstrate that SphK2-mediated S1P production plays a crucial role in the pathogenesis of CS-induced COPD-like disease by impairing CFTR activity and promoting pulmonary inflammation and fibrosis.

Increased CAP37 Expression in Stable Chronic Obstructive Pulmonary Disease.

Cationic antimicrobial protein of 37 kDa (CAP37), a neutrophil-derived protein originally identified for its antimicrobial activity, is now known to have many regulatory effects on host cells. However, its role in the pathogenesis of chronic obstructive pulmonary disease (COPD) has not been studied. We therefore investigated the expression of CAP37 in COPD and its effects on airway structural cells, including bronchial epithelial cells, smooth muscle cells, and fibroblasts. CAP37 was detected in the lung tissue, sputum, and plasma of COPD patients and the control subjects, as well as in the neutrophils stimulated by cigarette smoke extract (CSE). BEAS-2B cells, human bronchial smooth muscle cells (HBSMCs), and MRC-5 cells were treated with CAP37 or an anti-CAP37 antibody plus CAP37. Interleukin (IL)-6 and IL-8 were detected in the BEAS-2B cells. The cell proliferation was analyzed in the HBSMCs. Collagens were also detected in the MRC-5 cells. The expression of CAP37 was increased in the lung tissue and sputum supernatant of the COPD patients compared with the control subjects. The sputum supernatant CAP37 levels were inversely correlated with the forced expiratory volume in the first second percentage predicted in COPD. CAP37 was induced by CSE stimulation in the peripheral blood neutrophils from healthy non-smokers. CAP37 induced expression of IL-6 and IL-8 in BEAS-2B cells, and collagen expression of lung fibroblasts (MRC-5 cells). However, CAP37 did not significantly alter the proliferation of the HBSMCs. Our findings indicated that neutrophil-derived CAP37 may be involved in airway inflammation and fibrosis in COPD via affecting the bronchial epithelial cells, and fibroblasts, thus suggesting a possible role of CAP37 in the development and progression of COPD.

Cellular senescence is increased in airway smooth muscle cells of elderly persons with asthma.

Senescent cells can drive age-related tissue dysfunction partially via a senescence-associated secretory phenotype (SASP) involving proinflammatory and profibrotic factors. Cellular senescence has been associated with a structural and functional decline during normal lung aging and age-related diseases such as chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). Asthma in the elderly (AIE) represents a major healthcare burden. AIE is associated with bronchial airway hyperresponsiveness and remodeling, which involves increased cell proliferation and higher rates of fibrosis, and resistant to standard therapy. Airway smooth muscle (ASM) cells play a major role in asthma such as remodeling via modulation of inflammation and the extracellular matrix (ECM) environment. Whether senescent ASM cells accumulate in AIE and contribute to airway structural or functional changes is unknown. Lung tissues from elderly persons with asthma showed greater airway fibrosis compared with age-matched elderly persons with nonasthma and young age controls. Lung tissue or isolated ASM cells from elderly persons with asthma showed increased expression of multiple senescent markers including phospho-p53, p21, telomere-associated foci (TAF), as well as multiple SASP components. Senescence and SASP components were also increased with aging per se. These data highlight the presence of cellular senescence in AIE that may contribute to airway remodeling.

CREB1 Transcriptionally Activates LTBR to Promote the NF-κB Pathway and Apoptosis in Lung Epithelial Cells.

Bronchopulmonary dysplasia (BPD) is a prevalent chronic pediatric lung disease. Aberrant proliferation and apoptosis of lung epithelial cells are important in the pathogenesis of BPD. Lymphotoxin beta receptor (LTBR) is expressed in lung epithelial cells. Blocking LTBR induces regeneration of lung tissue and reverts airway fibrosis in young and aged mice. This study is aimed at revealing the role of LTBR in BPD. A mouse model of BPD and two in vitro models of BPD using A549 cells and type II alveolar epithelial (ATII) cells were established by exposure to hyperoxia. We found that LTBR and CREB1 exhibited a significant upregulation in lungs of mouse model of BPD. LTBR and CREB1 expression were also increased by hyperoxia in A549 and ATII cells. According to results of cell counting kit-8 assay and flow cytometry analysis, silencing of LTBR rescued the suppressive effect of hyperoxia on cell viability and its promotive effect on cell apoptosis of A549 and ATII cells. Bioinformatics revealed CREB1 as a transcriptional factor for LTBR, and the luciferase reporter assay and ChIP assay subsequently confirmed it. The NF-κB pathway was regulated by LTBR. CREB1 induced LTBR expression at the transcriptional level to regulate NF-κB pathway and further modulate A549 and ATII cells viability and apoptosis. In conclusion, this study revealed the CREB1/LTBR/NF-κB pathway in BPD and supported the beneficial role of LTBR silence in BPD by promoting viability and decreasing apoptosis of lung epithelial cells.

Lymphocytic Airway Inflammation in Lung Allografts.

Lung transplant remains a key therapeutic option for patients with end stage lung disease but short- and long-term survival lag other solid organ transplants. Early ischemia-reperfusion injury in the form of primary graft dysfunction (PGD) and acute cellular rejection are risk factors for chronic lung allograft dysfunction (CLAD), a syndrome of airway and parenchymal fibrosis that is the major barrier to long term survival. An increasing body of research suggests lymphocytic airway inflammation plays a significant role in these important clinical syndromes. Cytotoxic T cells are observed in airway rejection, and transcriptional analysis of airways reveal common cytotoxic gene patterns across solid organ transplant rejection. Natural killer (NK) cells have also been implicated in the early allograft damage response to PGD, acute rejection, cytomegalovirus, and CLAD. This review will examine the roles of lymphocytic airway inflammation across the lifespan of the allograft, including: 1) The contribution of innate lymphocytes to PGD and the impact of PGD on the adaptive immune response. 2) Acute cellular rejection pathologies and the limitations in identifying airway inflammation by transbronchial biopsy. 3) Potentiators of airway inflammation and heterologous immunity, such as respiratory infections, aspiration, and the airway microbiome. 4) Airway contributions to CLAD pathogenesis, including epithelial to mesenchymal transition (EMT), club cell loss, and the evolution from constrictive bronchiolitis to parenchymal fibrosis. 5) Protective mechanisms of fibrosis involving regulatory T cells. In summary, this review will examine our current understanding of the complex interplay between the transplanted airway epithelium, lymphocytic airway infiltration, and rejection pathologies.

MicroRNA-21 promotes epithelial-mesenchymal transition and migration of human bronchial epithelial cells by targeting poly (ADP-ribose) polymerase-1 and activating PI3K/AKT signaling.

Epithelial-mesenchymal transition (EMT) is known to be involved in airway remodeling and fibrosis of bronchial asthma. However, the molecular mechanisms leading to EMT have yet to be fully clarified. The current study was designed to reveal the potential mechanism of microRNA-21 (miR-21) and poly (ADP-ribose) polymerase-1 (PARP-1) affecting EMT through the PI3K/AKT signaling pathway. Human bronchial epithelial cells (16HBE cells) were transfected with miR-21 mimics/inhibitors and PARP-1 plasmid/small interfering RNA (siRNA). A dual luciferase reporter assay and biotin-labeled RNA pull-down experiments were conducted to verify the targeting relationship between miR-21 mimics and PARP-1. The migration ability of 16HBE cells was evaluated by Transwell assay. Quantitative real-time polymerase chain reaction and Western blotting experiments were applied to determine the expression of Snail, ZEB1, E-cadherin, N-cadherin, Vimentin, and PARP-1. The effects of the PI3K inhibitor LY294002 on the migration of 16HBE cells and EMT were investigated. Overexpression of miR-21 mimics induced migration and EMT of 16HBE cells, which was significantly inhibited by overexpression of PARP-1. Our findings showed that PARP-1 was a direct target of miR-21, and that miR-21 targeted PARP-1 to promote migration and EMT of 16HBE cells through the PI3K/AKT signaling pathway. Using LY294002 to block PI3K/AKT signaling pathway resulted in a significant reduction in the migration and EMT of 16HBE cells. These results suggest that miR-21 promotes EMT and migration of HBE cells by targeting PARP-1. Additionally, the PI3K/AKT signaling pathway might be involved in this mechanism, which could indicate its usefulness as a therapeutic target for asthma.

Downregulation of microRNA‑423‑5p suppresses TGF‑β1‑induced EMT by targeting FOXP4 in airway fibrosis.

Airway fibrosis (AF) is a common disease that can severely affect patient prognosis. Epithelial-mesenchymal transition (EMT) participates in the pathophysiological development of AF and several studies have demonstrated that some microRNAs (miRNAs) contribute to the development of EMT. The aim of this study was to investigate the function of miR-423-5p in the EMT process and its possible underlying mechanism in BEAS-2B cells. The present study utilized the BEAS-2B cell line to model EMT in AF. Online tools, fluorescence in situ hybridization analysis and an RNA pull-down assay were used to identify potential target genes of miR-423-5p. In addition, immunohistochemistry, wound healing assays, Transwell migration assays, flow cytometry, enzyme-linked immunosorbent assay, reverse transcription-quantitative PCR, western blot analysis and immunofluorescence staining were used to determine the function of miR-423-5p and its target gene in the EMT process in AF. The results indicated that the miR-423-5p expression in AF tissues and BEAS-2B cells stimulated with 10 ng/ml TGF-β1 for 24 h was significantly increased compared with that in the control group. Overexpression of miR-423-5p facilitated TGF-β1-induced EMT in BEAS-2B cells; by contrast, downregulation of miR-423-5p suppressed TGF-β1-induced EMT in BEAS-2B cells. Furthermore, forkhead box p4 (FOXP4) was identified as a potential target gene of miR-423-5p and changes in the miR-423-5p and FOXP4 expression were shown to significantly affect the expression of PI3K/AKT/mTOR pathway members. In summary, overexpression of miR-423-5P promoted the EMT process in AF by downregulating FOXP4 expression and the underlying mechanism may partly involve activation of the PI3K/AKT/mTOR pathway.

Exogenous leptin enhances markers of airway fibrosis in a mouse model of chronic allergic airways disease

BackgroundAsthma patients with comorbid obesity exhibit increased disease severity, in part, due to airway remodeling, which is also observed in mouse models of asthma and obesity. A mediator of remodeling that is increased in obesity is leptin. We hypothesized that in a mouse model of allergic airways disease, mice receiving exogenous leptin would display increased airway inflammation and fibrosis.MethodsFive-week-old male and female C57BL/6J mice were challenged with intranasal house dust mite (HDM) allergen or saline 5 days per week for 6 weeks (n = 6–9 per sex, per group). Following each HDM exposure, mice received subcutaneous recombinant human leptin or saline. At 48 h after the final HDM challenge, lung mechanics were evaluated and the mice were sacrificed. Bronchoalveolar lavage was performed and differential cell counts were determined. Lung tissue was stained with Masson’s trichrome, periodic acid-Schiff, and hematoxylin and eosin stains. Mouse lung fibroblasts were cultured, and whole lung mRNA was isolated.ResultsLeptin did not affect mouse body weight, but HDM+leptin increased baseline blood glucose. In mixed-sex groups, leptin increased mouse lung fibroblast invasiveness and increased lung Col1a1 mRNA expression. Total lung resistance and tissue damping were increased with HDM+leptin treatment, but not leptin or HDM alone. Female mice exhibited enhanced airway responsiveness to methacholine with HDM+leptin treatment, while leptin alone decreased total respiratory system resistance in male mice.ConclusionsIn HDM-induced allergic airways disease, administration of exogenous leptin to mice enhanced lung resistance and increased markers of fibrosis, with differing effects between males and females.

E-Cigarette Use, Small Airway Fibrosis, and Constrictive Bronchiolitis

BackgroundVaping, including the use of electronic cigarettes (e-cigarettes), has become increasingly prevalent, yet the associated long-term health risks are largely unknown. Given the prevalence of use, particularly among adolescents early in their lifespan, it is vital to understand the potential chronic pathologic sequelae of vaping.MethodsWe present the cases of four patients with chronic lung disease associated with e-cigarette use characterized by clinical evaluation, with pulmonary function tests (PFTs), chest high-resolution computed tomography (HRCT), endobronchial optical coherence tomography (EB-OCT) imaging, and histopathologic assessment.ResultsEach patient presented with shortness of breath and chest pain in association with a 3- to 8-year history of e-cigarette use, with mild progressive airway obstruction on PFTs and/or chest HRCT findings demonstrating evidence of air trapping and bronchial wall thickening. EB-OCT imaging performed in two patients showed small airway–centered fibrosis with bronchiolar narrowing and lumen irregularities. The predominant histopathologic feature on surgical lung biopsy was small airway–centered fibrosis, including constrictive bronchiolitis and MUC5AC overexpression in all patients. Patients who ceased vaping had a partial, but not complete, reversal of disease over 1 to 4 years.ConclusionsAfter thorough evaluation for other potential etiologies, vaping was considered to be the most likely common causal etiology for all patients due to the temporal association of symptomatic chronic lung disease with e-cigarette use and partial improvement in symptoms after e-cigarette cessation. In this series, we associate the histopathologic pattern of small airway–centered fibrosis, including constrictive bronchiolitis, with vaping, potentially defining a clinical and pathologic entity associated with e-cigarette use. (Funded in part by the National Institutes of Health.)

Hydrogen Sulfide Inhibits Bronchial Epithelial Cell Epithelial Mesenchymal Transition Through Regulating Endoplasm Reticulum Stress.

Epithelial mesenchymal transition (EMT) is a contributing factor in remodeling events of chronic obstructive pulmonary disease (COPD). Hydrogen sulfide (H2S) has been implicated in the pathogenesis of COPD, but the effect of H2S in regulating EMT and the underlying mechanisms is not clear. In this study, we assessed endoplasmic reticulum (ER) stress markers, EMT markers and associated signal molecules in rat lungs, bronchial epithelial cells, and human peripheral lung tissues to investigate the effect of H2S in regulating EMT and the underlying mechanisms. We found that EMT and ER stress occurred in lung epithelial cells, especially in the bronchial epithelial cells of smokers and COPD patients. In cigarette smoke (CS)-exposed rats, intraperitoneal injection of NaHS significantly alleviated CS-induced lung tissue damage, small airway fibrosis, ER stress, and EMT, while intraperitoneal injection of propargylglycine (cystathionine-gamma-lyase inhibitor) aggravated these effects induced by CS. In the nicotine-exposed 16HBE cells, an appropriate concentration of H2S donor not only inhibited nicotine-induced ER stress, but also inhibited nicotine-induced enhancement of cell migration ability and EMT. ER stress nonspecific inhibitors taurine and 4-phenyl butyric acid also inhibited nicotine-induced enhancement of cell migration ability and EMT. Both H2S and inositol-requiring enzyme 1 (IRE1) activation inhibitor 4μ8C inhibited nicotine-induced activation of IRE1, Smad2/3 and EMT. These results suggest that H2S inhibits CS- or nicotine-induced ER stress and EMT in bronchial epithelial cells and alleviates CS-induced lung tissue damage and small airway fibrosis. The IRE1 signal pathway and Smad2/3 may be responsible for the inhibitory effect of H2S.

Transcriptional Landscape of Chronic Lung Allograft Rejection in Humans

<h3>Purpose</h3> Chronic lung allograft dysfunction (CLAD) remains the main barrier to long-term survival after lung transplant. The main phenotypes of CLAD are bronchiolitis obliterans syndrome (BOS) with small airway fibrosis, and restrictive allograft syndrome (RAS) with extensive lung parenchymal fibrosis. Mechanisms of CLAD and the pathways active in BOS/RAS remain poorly understood. We hypothesized that bulk RNA sequencing (seq) of human CLAD lungs would help uncover pro-fibrotic pathways and phenotype-specific mechanisms. <h3>Methods</h3> At time of retransplantation, we obtained CLAD lung tissue from 27 BOS and 18 RAS. Negative controls included donor lungs (18) and lobectomy samples done for suspected cancers (14); positive controls came from patients with idiopathic pulmonary fibrosis (IPF) (19). RNA was extracted and submitted for bulk RNAseq at a depth of 50 million paired-end 100-base-pair reads. Differentially expressed genes were detected using DESeq2 and NOIseq. <h3>Results</h3> Top differentially expressed genes in CLAD vs. negative controls included genes involved in cell-matrix interactions (COL10A1, ADAM9) and cell proliferation (CST, MDK). Gene Ontology analysis showed higher expression of genes associated with fibrosis and motility, whereas genes involved in defense and immunity were decreased due to immunosuppression in CLAD vs. negative controls. Analyses to compare RAS to BOS are ongoing. As we anticipated an imperfect correlation between clinical phenotypes and transcriptomic endotypes, we performed unsupervised clustering of all samples. A subset of RAS/mixed samples clustered together and in close proximity to IPF, while other distinct clusters appeared independent of clinical phenotypes: These transcriptomic endotypes will merit further exploration. <h3>Conclusion</h3> This large cohort of lung samples allows a detailed analysis of the lung allograft transcriptome in different phenotypes of CLAD, enabling identification of the top differentially expressed genes and pathways in this poorly understood condition.

Nintedanib as an Anti-Fibrotic Therapy in a Mouse Model of Chronic Lung Allograft Dysfunction

<h3>Purpose</h3> Chronic lung allograft dysfunction (CLAD) is the leading cause of lung transplant failure, with 50% of patients developing it by five years post-transplant. CLAD is characterized by progressive fibrosis, and it has no effective therapies. Nintedanib is a multiple tyrosine kinase inhibitor used to treat idiopathic pulmonary fibrosis. Here we assess nintedanib's efficacy, with tacrolimus, as a potential preventative CLAD therapy in the heterotopic tracheal transplant mouse model of CLAD-like airway fibrosis. <h3>Methods</h3> We performed Balb/C (H-2^d)-to-C57BL/6 (H-2^b) transplants. To arrive at effective doses of nintedanib and tacrolimus alone, we treated nine groups of n=10 recipients with one of three doses of nintedanib (0, 25, 50mg/kg), or six doses of tacrolimus (0, 0.1, 0.25, 0.5, 1, 2mg/kg). Mice were given either drug daily for 28 days. Following sacrifice, tracheas underwent Masson-Trichrome staining and were graded for luminal fibrotic occlusion and epithelial necrosis. Kruskal-Wallis one-way analyses of variance were performed on both grades within drug treatments. <h3>Results</h3> We found that compared to the control (Fig. 1C), fibrotic occlusion was significantly reduced in nintedanib treatment groups, but that epithelial necrosis was unaffected (Fig. 1 A, B, D). In contrast, we found that high doses of tacrolimus eliminated both pathologies (Fig. 1 A, B, E). Lower doses of tacrolimus had a moderate effect on luminal occlusion, and no effect on epithelial necrosis. <h3>Conclusion</h3> Our results demonstrate nintedanib's potential as an anti-fibrotic drug in lung transplantation. Nintedanib caused a significant decrease in fibrotic occlusion, but epithelial necrosis was reduced only by tacrolimus. Based on this, we will examine the combined effects of the drugs to arrive at a treatment strategy with both immunosuppressive and antifibrotic components.

MNK/eIF4E Ser209 Inhibitor eFT-508 Prevents and Therapeutically Treats Fibrosis in a Murine Model of Restrictive Chronic Lung Allograft Rejection

<h3>Purpose</h3> Lung transplant is limited by poor outcomes due to chronic lung allograft dysfunction, CLAD. A fulminant CLAD phenotype, restrictive allograft syndrome (RAS), with limited therapies underscores the need to understand underlying mechanisms. MNK1 kinase is a key translational regulator of cellular functions via eIF4E serine 209 phosphorylation. Here we investigate the role of MNK/eIF4E Ser209 in mesenchymal cell activation and the therapeutic effectiveness of eFT-508 in a murine model of RAS. <h3>Methods</h3> Human lung allograft derived MCs treated with eFT-508 (10uM x 24h) were immunoblotted for collagen I, alpha smooth muscle actin, CD44, autotaxin. A modified boyden chamber assay was utilized for migration. We recently reported a murine RAS model, B6D2F1/J into C57BL6/J. Mice were administered eFT-508 5mg/kg/daily/gavage in a preventive group days 7-28, or therapeutic group days 14-28. <h3>Results</h3> Human allograft derived MCs from CLAD patients demonstrated 4-fold increase in MNK1 (Thr197/202) and eIF4E Ser209 compared to non-fibrotic MCs. Upon eFT-508 treatment, we observed reduced eIF4E Ser209, collagen I, alpha smooth muscle actin and SPARC expression, and migration (n=7; p<0.05). CD44 and autotaxin protein expression was decreased upon eFT-508 treatment, along with secreted autotaxin activity (n=9; p=0.0005). <i>In vivo</i> preventive treatment with eFT-508 decreased airway fibrosis upon histological examination utilizing trichrome staining. Pleural thickness measurements were also reduced compared to vehicle treated controls. A significant reduction in hydroxyproline content, autotaxin secretion, and activity were also noted in eFT-508 treated transplant lung homogenates (n=7; p<0.001). Therapeutic treatment with eFT-508 reduced hydroxyproline content compared to vehicle treated allografts (n=4; p=0.0252). <h3>Conclusion</h3> MNK/eIF4E Ser209 inhibition reduced fibrotic protein expression and migration, demonstrating a role for this pathway in MC activation. <i>In vivo</i> MNK/eIF4E Ser209 inhibition reduced graft fibrosis by preventive and therapeutic treatment regimens in a murine model of RAS. This data highlights a novel therapeutic option for preventing development and progression of RAS.

Inhibiting S100A8/A9 Attenuates Airway Obstruction in a Mouse Heterotopic Tracheal Transplantation Model

<h3>Purpose</h3> Chronic lung allograft dysfunction (CLAD) is a major cause of mortality after lung transplantation (LTx). The main pathogenesis of CLAD is fibrosis of the small airways or lung parenchyma. Neutralizing antibodies against S100A8/A9, an inflammatory protein, have been shown to inhibit lung fibrosis in mouse models. In the present study, we tested the hypothesis that S100A8/A9 antibodies suppress airway fibrosis in a mouse model. <h3>Methods</h3> A mouse heterotopic tracheal transplantation model was used. The anti-S100A8/A9 monoclonal antibody or control IgG were intraperitoneally administered twice a week. The rate of graft lumen occlusion, the positivity of the fibroblast marker α-smooth muscle actin (SMA), and mRNA expression of cytokines and chemokines were evaluated. <h3>Results</h3> The luminal obstruction ratio at day 21 was significantly higher in the treatment group than in the control group (p = 0.0023) (Fig.1A, 1B and 2A). The αSMA-positive area in submucosal layer was significantly smaller in the treatment group than in the control group (p = 0.0376) (Fig 1C, 1D and 2B). The expression levels of TGFβ (p = 0.0026) and Collagen 3a1 (p = 0.0238) at day 21 by qPCR were significantly lower in the treatment group than in the control group. Conversely, expression levels of inflammatory cytokines in the treatment group was equivalent to those in the control group. <h3>Conclusion</h3> S100A8/A9 antibody ameliorated airway obstruction by reducing collagen production of αSMA positive myofibroblast without suppression of inflammatory responses in a mouse model. The heterodimer S100A8/A9 can be a novel therapeutic target for CLAD after LTx.

Clusterin as a serum biomarker candidate contributes to the lung fibroblasts activation in chronic obstructive pulmonary disease.

Background:Fibrosis in the peripheral airways contributes to airflow limitation in patients with chronic obstructive pulmonary disease (COPD). However, the key proteins involved in its development are still poorly understood. Thus, we aimed to identify the differentially expressed proteins (DEPs) between smoker patients with and without COPD and elucidate the molecular mechanisms involved by investigating the effects of the identified biomarker candidate on lung fibroblasts.Methods:The potential DEPs were identified by isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic analysis. The messenger RNA and protein levels of clusterin (CLU) in COPD patients and 12% cigarette smoke extract (CSE)-treated human bronchial epithelial cells were determined at the indicated time points. Furthermore, an in vitro COPD model was established via the administration of 8% CSE to normal human lung fibroblasts (NHLFs) at indicated time points. The effects of CSE treatment and CLU silencing on proliferation and activation of lung fibroblasts were analyzed.Results:A total of 144 DEPs were identified between COPD patients and normal smokers. The iTRAQ-based proteomics and bioinformatics analyses identified CLU as a serum biomarker candidate. We also discovered that CLU levels were significantly increased (P < 0.0001) in Global Initiative for Obstructive Lung Disease II, III, and IV patients and correlated (P < 0.0001) with forced expiratory volume in 1 s (R = −0.7705), residual volume (RV) (R = 0.6281), RV/total lung capacity (R = 0.5454), and computerized tomography emphysema (R = 0.7878). Similarly, CLU levels were significantly increased in CSE-treated cells at indicated time points (P < 0.0001). The CSE treatment significantly inhibited the proliferation, promoted the inflammatory response, differentiation of NHLFs, and collagen matrix deposition, and induced the apoptosis of NHLFs; however, these effects were partially reversed by CLU silencing.Conclusion:Our findings suggest that CLU may play significant roles during airway fibrosis in COPD by regulating lung fibroblast activation.

A survey of patients with laryngotracheal stenosis on future clinical trial design.

Laryngotracheal stenosis is a rare but devastating proximal airway fibrosis that restricts a patient's ability to breathe. Treatment is primarily surgical and to date, there has never been a multi-institutional, randomized, prospective, and interventional clinical trial for a medical therapy to treat laryngotracheal stenosis. Therefore, we aimed to obtain patient feedback to guide successful trial design, recruitment, retention, and for identifying potential barriers to study participation. Over 1000 members of an international laryngotracheal stenosis online support community (the Living with Idiopathic Subglottic Stenosis Facebook group) were sent two questionnaires for a proposed interventional double-blinded, randomized, placebo-controlled clinical trial. A total of 317 and 558 participants responded to the first and second surveys, respectively. The majority of participants (77%) were willing to consider enrollment, regardless of having a 50% chance of receiving placebo versus treatment (78%). The majority (84%) of participants were willing to travel 200 miles to participate for up to six in-person visits over 50 days. Specific side effects, including anemia/thrombocytopenia (72%) or risk of infection (69.3%) had the greatest impact on clinical trial participation with other side effects (peripheral edema (53%), oral ulcers (51%), and gastrointestinal side effects (41%)) having less impact. Patients with laryngotracheal stenosis possess nuanced insight into their disease and treatment options. As a group, they are extremely motivated for better therapies. Future laryngotracheal stenosis clinical trials should focus on providing excellent side effect -related education and utilizing feedback from online advocacy groups to optimize recruitment and retention.

Targeting chronic COVID-19 lung injury; Tofacitinib can be used against tissue-resident memory T cells

Post-Covid pulmonary fibrosis is evident following severe COVID-19. There is an urgent need to identify the cellular and pathophysiological characteristics of chronic lung squeals of Covid-19 for the development of future preventive and/or therapeutic interventions. Tissue-resident memory T (TRM) cells can mediate local immune protection against infections and cancer. Less beneficially, lung TRM cells cause chronic airway inflammation and fibrosis by stimulating pathologic inflammation. The effects of Janus kinase (JAK), an inducer pathway of cytokine storm, inhibition on acute Covid-19 cases have been previously evaluated. Here, we propose that Tofacitinib by targeting the CD8+ TRM cells could be a potential candidate for the treatment of chronic lung diseases induced by acute SARS-CoV-2 infection.

Prolonged Surgical Interval Following Chemotherapy in a Patient With Idiopathic Subglottic Stenosis (iSGS): Case Report and Brief Review of Literature

Objective: To report a case of a patient with idiopathic subglottic stenosis (iSGS) who no longer required surgical intervention for her disease following a chemotherapy regimen of carboplatin and doxorubicin for ovarian cancer. A brief review of the literature and discussion on the possible mechanism of action of chemotherapy agents affecting fibrosis is included. Methods: Case report and review of literature. Results: A 71-year-old Caucasian woman with iSGS was managed with serial endoscopic excision and dilation (n = 5) from 2013 to 2017 with an average dilation interval of 12.3 months. After a course of doxorubicin and carboplatin to treat her ovarian cancer, we observed that her airway stenosis surprisingly stabilized, and has no longer required a surgical dilation for 45 months, which signifies an increase of 33 months when compared to her averaged dilation interval (12.3 months) prior to her second course of chemotherapy. Conclusion: We present an iSGS patient whose fibrosis was arrested following carboplatin/doxorubicin treatment. While a single case, a possible mechanism is carboplatin/doxorubicin’s inhibition of pathologic CD4 lymphocytes that propagate laryngotracheal fibrosis. Further investigation of like mechanisms may allow for translation of local agents with inhibitory effects on CD4+ cells and/or fibroblasts as a novel therapy for airway fibrosis.

RETRACTED ARTICLE: MicroRNA-335-5p alleviates inflammatory response, airway fibrosis, and autophagy in childhood asthma through targeted regulation of autophagy related 5

Statement of Retraction Qingbin Liang, Jingjing He, Qian Yang, Qinghua Zhang & Yingjun Xu (2022) MicroRNA-335-5p alleviates inflammatory response, airway fibrosis, and autophagy in childhood asthma through targeted regulation of autophagy related 5, Bioengineered, 13:1, 1791-1801, DOI: 10.1080/21655979.2021.1996315 Since publication, significant concerns have been raised about the integrity of the data and reported results in the article. When approached for an explanation, the authors did not provide their original data or any necessary supporting information. As verifying the validity of published work is core to the integrity of the scholarly record, we are therefore retracting the article. All authors listed in this publication have been informed. We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as ‘Retracted’.