Airway Epithelial Repair Research Articles

Delayed airway epithelial repair is correlated with airway obstruction in young adults born very preterm

Delayed airway epithelial repair is correlated with airway obstruction in young adults born very preterm

P039 Lactonase benefits to counteract the impacts of Pseudomonas aeruginosa virulence on the early phases of airway epithelial wound repair in cystic fibrosis

P039 Lactonase benefits to counteract the impacts of Pseudomonas aeruginosa virulence on the early phases of airway epithelial wound repair in cystic fibrosis

Distinct Effects of Respiratory Viral Infection Models on miR-149-5p, IL-6 and p63 Expression in BEAS-2B and A549 Epithelial Cells.

Respiratory viruses cause airway inflammation, resulting in epithelial injury and repair. miRNAs, including miR-149-5p, regulate different pathological conditions. We aimed to determine how miR-149-5p functions in regulating pro-inflammatory IL-6 and p63, key regulators of airway epithelial wound repair, in response to viral proteins in bronchial (BEAS-2B) and alveolar (A549) epithelial cells. BEAS-2B or A549 cells were incubated with poly (I:C, 0.5 µg/mL) for 48 h or SARS-CoV-2 spike protein-1 or 2 subunit (S1 or S2, 1 μg/mL) for 24 h. miR-149-5p was suppressed in BEAS-2B challenged with poly (I:C), correlating with IL-6 and p63 upregulation. miR-149-5p was down-regulated in A549 stimulated with poly (I:C); IL-6 expression increased, but p63 protein levels were undetectable. miR-149-5p remained unchanged in cells exposed to S1 or S2, while S1 transfection increased IL-6 expression in BEAS-2B cells. Ectopic over-expression of miR-149-5p in BEAS-2B cells suppressed IL-6 and p63 mRNA levels and inhibited poly (I:C)-induced IL-6 and p63 mRNA expressions. miR-149-5p directly suppressed IL-6 mRNA in BEAS-2B cells. Hence, BEAS-2B cells respond differently to poly (I:C), S1 or S2 compared to A549 cells. Thus, miR-149-5p dysregulation may be involved in poly (I:C)-stimulated but not S1- or S2-stimulated increased IL-6 production and p63 expression in BEAS-2B cells.

Competitive-like binding between carbon black and CTNNB1 to ΔNp63 interpreting the abnormal respiratory epithelial repair after injury

Airway epithelium is extraordinary vulnerable to damage owning to continuous environment exposure. Subsequent repair is therefore essential to restore the homeostasis of respiratory system. Disruptions in respiratory epithelial repair caused by nanoparticles exposure have been linked to various human diseases, yet implications in repair process remain incompletely elucidated. This study aims to elucidate the key stage in epithelial repair disturbed by carbon black (CB) nanoparticles, highlighting the pivotal role of ΔNp63 in mediating the epithelium repair. A competitive-like binding between CB and beta-catenin 1 (CTNNB1) to ΔNp63 is proposed to elaborate the underlying toxicity mechanism. Specifically, CB exhibits a remarkable inhibitory effect on cell proliferation, leading to aberrant airway epithelial repair, as validated in air-liquid culture. ΔNp63 drives efficient epithelial proliferation during CB exposure, and CTNNB1 was identified as a target of ΔNp63 by bioinformatics analysis. Further molecular dynamics simulation reveals that oxygen-containing functional groups on CB disrupt the native interaction of CTNNB1 with ΔNp63 through competitive-like binding pattern. This process modulates CTNNB1 expression, ultimately restraining proliferation during respiratory epithelial repair. Overall, the current study elucidates that the diminished interaction between CTNNB1 and ΔNp63 impedes respiratory epithelial repair in response to CB exposure, thereby enriching the public health risk assessment on CB-related respiratory diseases.

Panax notoginseng saponin R1 improves glucocorticoid-inhibited airway epithelium repair via glucocorticoid receptor β

BackgroundPanax notoginseng saponin R1(PNS-R1), derived from Panax notoginseng roots, promotes wound repair, whereas glucocorticoids can inhibit the repair of airway epithelial damage in asthma. ObjectiveThis study investigated whether PNS-R1 counteracts the inhibitory effects of glucocorticoids on the repair of airway epithelial damage in asthma. MethodsIn vivo, female C57BL/6 mice were sensitized, challenged with house dust mites (HDM), and treated with dexamethasone, PNS-R1, and/or adenovirus GRβ-shRNA. Airway epithelium damage was examined using pathological sections of the trachea and bronchi, markers of airway inflammation, epithelial cells in bronchoalveolar lavage fluid, and expression of the E-cadherin protein. In vitro, we treated 16HBE cells with dexamethasone, PNS-R1, and/or GRβ-siRNA and detected cell proliferation and migration. The expression of GRβ and key components of MKP-1 and Erk1/2 were detected by western blotting. ResultsIn vivo, PNS-R1 reduced airway inflammation, hyperresponsiveness, and mucus hypersecretion; the combination of PNS-R1 and dexamethasone promoted airway epithelial integrity and reduced cell detachment. In vitro, PNS-R1 alleviated the inhibition of bronchial epithelial cell growth, migration, and proliferation by dexamethasone; PNS-R1 promoted GRβ expression, inhibited MKP-1 protein expression, and activated MAPK signaling, thereby promoting airway epithelial cell proliferation and repair. ConclusionsPanax notoginseng saponin R1 alleviated the inhibitory effect of dexamethasone on the repair of airway epithelial damage in asthmatic mice, likely by promoting the proliferation of airway epithelial cells by stimulating GRβ expression and activating the MAPK pathway.

Formononetin ameliorates airway inflammation by suppressing ESR1/NLRP3/Caspase-1 signaling in asthma

Since inhaled glucocorticoids are the first-line treatment for asthma, asthma management becomes extremely difficult when asthma does not react well to glucocorticoids. Formononetin, a bioactive isoflavone and typical phytoestrogen, has been shown to have an anti-inflammatory impact while alleviating epithelial barrier dysfunction, which plays a role in the pathogenesis of allergic illnesses like asthma. However, the biological mechanisms behind this impact are unknown. As a result, we set out to investigate the effects of formononetin on airway inflammation and epithelial barrier repair in house dust mite (HDM)-induced asthmatic mice. We further expanded on formononetin's putative mode of action in reducing airway inflammation by modifying epithelial barrier dysfunction. In the current study, researchers discovered that formononetin significantly lowered total IgE levels in serum and interleukin (IL)-4, IL-6, and IL-17A levels in bronchoalveolar lavage fluid (BALF) in HDM-challenged asthmatic mice. Experiments on cell proliferation, migration, and apoptosis were performed in vitro to determine the effect of formononetin on bronchial epithelial barrier repair. Furthermore, in lipopolysaccharide (LPS)-stimulated 16HBE cells, formononetin increased cell proliferation and migration while preventing apoptosis and lowering the Bax/Bcl-2 ratio. In vitro and in vivo, formononetin significantly inhibited toll-like receptor 4 (TLR4) and estrogen receptor (ESR1)/Nod-like receptor family pyrin domain-containing protein 3 (NLRP3)/Caspase-1 signaling. These findings show that formononetin can reduce airway inflammation in HDM-challenged asthmatic mice by promoting epithelial barrier repair and possibly by inhibiting ESR1/NLRP3/Caspase-1 signaling as the underlying mechanism; formononetin could be a promising alternative treatment for asthma.

173 Role of CFTR in airway epithelial regeneration and repair: Studies from novel human basal cell lines

173 Role of CFTR in airway epithelial regeneration and repair: Studies from novel human basal cell lines

Mechanisms of airway epithelial injury and abnormal repair in asthma and COPD.

The airway epithelium comprises of different cell types and acts as a physical barrier preventing pathogens, including inhaled particles and microbes, from entering the lungs. Goblet cells and submucosal glands produce mucus that traps pathogens, which are expelled from the respiratory tract by ciliated cells. Basal cells act as progenitor cells, differentiating into different epithelial cell types, to maintain homeostasis following injury. Adherens and tight junctions between cells maintain the epithelial barrier function and regulate the movement of molecules across it. In this review we discuss how abnormal epithelial structure and function, caused by chronic injury and abnormal repair, drives airway disease and specifically asthma and chronic obstructive pulmonary disease (COPD). In both diseases, inhaled allergens, pollutants and microbes disrupt junctional complexes and promote cell death, impairing the barrier function and leading to increased penetration of pathogens and a constant airway immune response. In asthma, the inflammatory response precipitates the epithelial injury and drives abnormal basal cell differentiation. This leads to reduced ciliated cells, goblet cell hyperplasia and increased epithelial mesenchymal transition, which contribute to impaired mucociliary clearance and airway remodelling. In COPD, chronic oxidative stress and inflammation trigger premature epithelial cell senescence, which contributes to loss of epithelial integrity and airway inflammation and remodelling. Increased numbers of basal cells showing deregulated differentiation, contributes to ciliary dysfunction and mucous hyperproduction in COPD airways. Defective antioxidant, antiviral and damage repair mechanisms, possibly due to genetic or epigenetic factors, may confer susceptibility to airway epithelial dysfunction in these diseases. The current evidence suggests that a constant cycle of injury and abnormal repair of the epithelium drives chronic airway inflammation and remodelling in asthma and COPD. Mechanistic understanding of injury susceptibility and damage response may lead to improved therapies for these diseases.

EPs® 7630 Stimulates Tissue Repair Mechanisms and Modifies Tight Junction Protein Expression in Human Airway Epithelial Cells

Airway epithelium repair after infection consists of wound repair, re-synthesis of the extracellular matrix (ECM), and tight junction proteins. In humans, EPs® 7630 obtained from Pelargonium sidoides roots reduces the severity and duration of acute respiratory tract infections. The effect of EPs® 7630 on tissue repair of rhinovirus-16 (RV-16) infected and control human airway epithelial cells was assessed for: (i) epithelial cell proliferation by manual cell counts, (ii) epithelial wound repair by “scratch assay”, (iii) ECM composition by Western-blotting and cell-based ELISA, and (iv) epithelial tight junction proteins by Western-blotting. EPs® 7630 stimulated cell proliferation through cAMP, CREB, and p38 MAPK. EPs® 7630 significantly improved wound repair. Pro-inflammatory collagen type-I expression was reduced by EPs® 7630, while fibronectin was increased. Virus-binding tight junction proteins desmoglein2, desmocollin2, ZO-1, claudin1, and claudin4 were downregulated by EPs® 7630. The RV16-induced shift of the ECM towards the pro-inflammatory type was prevented by EPs® 7630. Most of the effects of EPs® 7630 on tissue repair and regeneration were sensitive to inhibition of cAMP-induced signaling. The data suggest that EPs® 7630-dependent modification of epithelial cell metabolism and function might underlie the faster recovery time from viral infections, as reported by others in clinical studies.

151 TRPA1/V3-Dependent Regulation of Airway Epithelial Cell Damage and Repair Triggered by wood/Biomass Smoke Particulate

Abstract Wood/biomass smoke particulate material (WBSPM) is a pervasive environmental pollutant. Acute high-dose inhalation exposure can cause airway epithelial cell (AEC) damage and respiratory dysfunction. We hypothesized that AEC damage is limited by compensatory signaling to allow epithelial repair. RNA sequencing, proteomics, targeted interventions, and cultured human AECs treated with WBSPM and Transient Receptor Potential Ankyrin-1 (TRPA1) agonists revealed TRPA1-driven endoplasmic reticulum stress (ERS) and oxidative stress (OS) as contributory pathways to cytotoxicity. Alternatively, TRP vanilloid-3 (TRPV3) counteracted these events despite also being activated by WBSPM. Using the TRPA1 agonist AITC (and others) as a surrogate for WBSPM, morphological distortion indicative of AEC damage was observed 2-4h post-treatment; at >6h cells recovered. Strikingly, at 2h, the abundance of only 6 proteins changed including loss of fibronectin and tubulin and increased heme oxygenase 1. At 6h, 36 proteins changed, including ER chaperones and transcriptional/cell cycle regulatory proteins, OS-response, and structural/matrix proteins. Analysis of the phosphoproteome revealed changes in 2672 and 1886 unique phosphosites at 2 and 6h, attributable to PKC, p38 MAPK, EGFR, Akt and other kinase activities based on “phosphosite-GSEA” analysis. A kinase inhibitor screen linked PKC, p38 MAPK, GSK3b and ERK1/2 with cytotoxicity, while EGFR, MEK1/2, JNK1/2/3 and Akt were protective. Considering that TRPV3 expression is regulated by EGFR following WBSPM injury and TRPV3 enhanced adhesion and slowed proliferation via attenuated EGFR signaling, we propose a mechanism whereby the balance of TRPA1, TRPV3, and calcium/growth factor receptor-dependent kinase signaling coordinates WBSPM injury, compensation and repair.

Vitamin A-regulated ciliated cells promote airway epithelium repair in an asthma mouse model.

Asthma is a chronic inflammatory airway disease that causes damage to and exfoliation of the airway epithelium. The continuous damage to the airway epithelium in asthma cannot be repaired quickly and generates irreversible damage, repeated attacks, and aggravation. Vitamin A (VA) has multifarious biological functions that include maintaining membrane stability and integrity of the structure and function of epithelial cells. Our research explored the role of VA in repairing the airway epithelium and provided a novel treatment strategy for asthma. A mouse asthma model was established by house dust mite (HDM) and treated with VA by gavage. Human bronchial epithelial (16HBE) cells were treated with HDM and all-trans retinoic acid (ATRA) in vitro. We analyzed the mRNA and protein expression of characteristic markers, such as acetyl-α-tubulin (Ac-TUB) and FOXJ1 in ciliated cells and MUC5AC in secretory cells, mucus secretion, airway inflammation, the morphology of cilia, and the integrity of the airway epithelium. Findings showed destruction of airway epithelial integrity, damaged cilia, high mucus secretion, increased MUC5AC expression, and decreased Ac-TUB and FOXJ1 expression in asthmatic mice. The VA intervention reversed the effect on Ac-TUB and FOXJ1 and promoted ciliated cells to repair the damage and maintain airway epithelial integrity. In 16HBE cells, we could confirm that ATRA promoted the expression of Ac-TUB and FOXJ1. These results demonstrated that VA-regulated ciliated cells to repair the damaged airway epithelium caused by asthma and maintain airway epithelial integrity. VA intervention is a potential adjunct to conventional treatment for asthma.

The role of mast cells in the pathogenesis of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is one of major causes of chronic noncommunicable diseases and mortality worldwide. The roles of macrophages, T-lymphocytes, neutrophils, and other cells in the development of chronic inflammation in this disease are well studied, but more and more researchers have focused on mast cells (MC) in recent years.The aim of this work is to summarize the data of experimental and clinical studies on the possible role of MCs in the pathogenesis of COPD. To this end, the review analyzed data on the relationship between MCs and respiratory function parameters in COPD, as well as the distribution of MCs subpopulations in different parts of the respiratory tract. The involvement of proteases (chymase and tryptase) in the development of inflammatory and fibrotic changes in COPD is discussed. The review presents research findings that indicate the possible involvement of chymase in pulmonary artery remodeling, increased secretion of mucins, and slowing down the airway epithelial repair. The role of MC tryptase in the development of fibrotic changes in the lungs and airways in COPD is also highlighted. A separate section of the review is devoted to chemokines that promote MC migration and their specific receptor. Chemokines play a special role in the development of inflammation in COPD.Conclusion. The available data suggest that MCs play a major role in the pathogenesis of COPD. Because of the inconsistency of some results, further clinical studies in larger cohorts of patients are needed.

GLI1+ cells are a source of repair-supportive mesenchymal cells (RSMCs) during airway epithelial regeneration

Repair-supportive mesenchymal cells (RSMCs) have been recently reported in the context of naphthalene (NA)-induced airway injury and regeneration. These cells transiently express smooth muscle actin (Acta2) and are enriched with platelet-derived growth factor receptor alpha (Pdgfra) and fibroblast growth factor 10 (Fgf10) expression. Genetic deletion of Ctnnb1 (gene coding for beta catenin) or Fgf10 in these cells using the Acta2-Cre-ERT2 driver line after injury (defined as NA-Tam condition; Tam refers to tamoxifen) led to impaired repair of the airway epithelium. In this study, we demonstrate that RSMCs are mostly captured using the Acta2-Cre-ERT2 driver when labeling occurs after (NA-Tam condition) rather than before injury (Tam-NA condition), and that their expansion occurs mostly between days 3 and 7 following NA treatment. Previous studies have shown that lineage-traced peribronchial GLI1+ cells are transiently amplified after NA injury. Here, we report that Gli1 expression is enriched in RSMCs. Using lineage tracing with Gli1Cre−ERT2 mice combined with genetic inactivation of Fgf10, we show that GLI1+ cells with Fgf10 deletion fail to amplify around the injured airways, thus resulting in impaired airway epithelial repair. Interestingly, Fgf10 expression is not upregulated in GLI1+ cells following NA treatment, suggesting that epithelial repair is mostly due to the increased number of Fgf10-expressing GLI1+ cells. Co-culture of SCGB1A1+ cells with GLI1+ cells isolated from non-injured or injured lungs showed that GLI1+ cells from these two conditions are similarly capable of supporting bronchiolar organoid (or bronchiolosphere) formation. Single-cell RNA sequencing on sorted lineage-labeled cells showed that the RSMC signature resembles that of alveolar fibroblasts. Altogether, our study provides strong evidence for the involvement of mesenchymal progenitors in airway epithelial regeneration and highlights the critical role played by Fgf10-expressing GLI1+ cells in this context.

Cigarette Smoke Impairs Airway Epithelial Wound Repair: Role of Modulation of Epithelial-Mesenchymal Transition Processes and Notch-1 Signaling.

Cigarette smoke (CS) induces oxidative stress and chronic inflammation in airway epithelium. It is a major risk factor for respiratory diseases, characterized by epithelial injury. The impact of CS on airway epithelial repair, which involves epithelial-mesenchymal transition (EMT) and the Notch-1 pathway, is incompletely understood. In this study, we used primary bronchial epithelial cells (PBECs) to evaluate the effect of CS on epithelial repair and these mechanisms. The effect of CS and/or TGF-beta1 on wound repair, various EMT and Notch-1 pathway markers and epithelial cell markers (TP63, SCGB1A) was assessed in PBECs cultured submerged, at the air–liquid interface (ALI) alone and in co-culture with fibroblasts. TGF-beta1 increased epithelial wound repair, activated EMT (shown by decrease in E-cadherin, and increases in vimentin, SNAIL1/SNAIL2/ZEB1), and increased Notch-1 pathway markers (NOTCH1/JAGGED1/HES1), MMP9, TP63, SCGB1A1. In contrast, CS decreased wound repair and vimentin, NOTCH1/JAGGED1/HES1, MMP9, TP63, SCGB1A1, whereas it activated the initial steps of the EMT (decrease in E-cadherin and increases in SNAIL1/SNAIL2/ZEB1). Using combined exposures, we observed that CS counteracted the effects of TGF-beta1. Furthermore, Notch signaling inhibition decreased wound repair. These data suggest that CS inhibits the physiological epithelial wound repair by interfering with the normal EMT process and the Notch-1 pathway.

Restoring airway epithelial homeostasis in Cystic Fibrosis

Cystic fibrosis (CF), the most common life-threatening genetic disorder in Caucasians, is caused by recessive mutations in the Cystic Fibrosis Transmembrane Regulator (CFTR) gene encoding a chloride ion channel. Aberrant function of CFTR involves mucus- and sweat-producing epithelia affecting multiple organs, including airways and lungs. This condition facilitates the colonization of fungi, bacteria, or viruses. Recurrent antibiotic administration is commonly used to treat pathogen infections leading to the insurgence of resistant bacteria and to a chronic inflammatory state that jeopardizes airway epithelium repair. The phenotype of patients carrying CFTR mutations does not always present a strict correlation with their genotype, suggesting that the disease may occur because of multiple additive effects. Among them, the frequent microbiota dysbiosis observed in patients affected by CF, might be one cause of the discrepancy observed in their genotype-phenotype correlation. Interestingly, the abnormal polarity of the CF airway epithelium has been observed also under non-infectious and non-inflammatory conditions, suggesting that CFTR dysfunction “per se” perturbs epithelial homeostasis. New pathogen- or host-directed strategies are thus needed to counteract bacterial infections and restore epithelial homeostasis in individuals with CF. In this review, we summarized alternative cutting-edge approaches to high-efficiency modulator therapy that might be promising for these patients.

Diacetyl inhalation impairs airway epithelial repair in mice infected with influenza A virus.

Bronchiolitis obliterans (BO) is a debilitating disease of the small airways that can develop following exposure to toxic chemicals as well as respiratory tract infections. BO development is strongly associated with diacetyl (DA) inhalation exposures at occupationally relevant concentrations or severe influenza A viral (IAV) infections. However, it remains unclear whether lower dose exposures or more mild IAV infections can result in similar pathology. In the current work, we combined these two common environmental exposures, DA and IAV, to test whether shorter DA exposures followed by sublethal IAV infection would result in similar airways disease. Adult mice exposed to DA vapors 1 h/day for 5 consecutive days followed by infection with the airway-tropic IAV H3N2 (HKx31) resulted in increased mortality, increased bronchoalveolar lavage (BAL) neutrophil percentage, mixed obstruction and restriction by lung function, and subsequent airway remodeling. Exposure to DA or IAV alone failed to result in significant pathology, whereas mice exposed to DA + IAV showed increased α-smooth muscle actin (αSMA) and epithelial cells coexpressing the basal cell marker keratin 5 (KRT5) with the club cell marker SCGB1A1. To test whether DA exposure impairs epithelial repair after IAV infection, mice were infected first with IAV and then exposed to DA during airway epithelial repair. Mice exposed to IAV + DA developed similar airway remodeling with increased subepithelial αSMA and epithelial cells coexpressing KRT5 and SCGB1A1. Our findings reveal an underappreciated concept that common environmental insults while seemingly harmless by themselves can have catastrophic implications on lung function and long-term respiratory health when combined.

AI-Driven Cell Tracking to Enable High-Throughput Drug Screening Targeting Airway Epithelial Repair for Children with Asthma.

The airway epithelium of children with asthma is characterized by aberrant repair that may be therapeutically modifiable. The development of epithelial-targeting therapeutics that enhance airway repair could provide a novel treatment avenue for childhood asthma. Drug discovery efforts utilizing high-throughput live cell imaging of patient-derived airway epithelial culture-based wound repair assays can be used to identify compounds that modulate airway repair in childhood asthma. Manual cell tracking has been used to determine cell trajectories and wound closure rates, but is time consuming, subject to bias, and infeasible for high-throughput experiments. We therefore developed software, EPIC, that automatically tracks low-resolution low-framerate cells using artificial intelligence, analyzes high-throughput drug screening experiments and produces multiple wound repair metrics and publication-ready figures. Additionally, unlike available cell trackers that perform cell segmentation, EPIC tracks cells using bounding boxes and thus has simpler and faster training data generation requirements for researchers working with other cell types. EPIC outperformed publicly available software in our wound repair datasets by achieving human-level cell tracking accuracy in a fraction of the time. We also showed that EPIC is not limited to airway epithelial repair for children with asthma but can be applied in other cellular contexts by outperforming the same software in the Cell Tracking with Mitosis Detection Challenge (CTMC) dataset. The CTMC is the only established cell tracking benchmark dataset that is designed for cell trackers utilizing bounding boxes. We expect our open-source and easy-to-use software to enable high-throughput drug screening targeting airway epithelial repair for children with asthma.

SLC6A14 Impacts Cystic Fibrosis Lung Disease Severity via mTOR and Epithelial Repair Modulation.

Cystic fibrosis (CF), due to pathogenic variants in CFTR gene, is associated with chronic infection/inflammation responsible for airway epithelium alteration and lung function decline. Modifier genes induce phenotype variability between people with CF (pwCF) carrying the same CFTR variants. Among these, the gene encoding for the amino acid transporter SLC6A14 has been associated with lung disease severity and age of primary airway infection by the bacteria Pseudomonas aeruginosa. In this study, we investigated whether the single nucleotide polymorphism (SNP) rs3788766, located within SLC6A14 promoter, is associated with lung disease severity in a large French cohort of pwCF. We also studied the consequences of this SNP on SLC6A14 promoter activity using a luciferase reporter and the role of SLC6A14 in the mechanistic target of rapamycin kinase (mTOR) signaling pathway and airway epithelial repair. We confirm that SLC6A14 rs3788766 SNP is associated with lung disease severity in pwCF (p = 0.020; n = 3,257, pancreatic insufficient, aged 6–40 years old), with the minor allele G being deleterious. In bronchial epithelial cell lines deficient for CFTR, SLC6A14 promoter activity is reduced in the presence of the rs3788766 G allele. SLC6A14 inhibition with a specific pharmacological blocker reduced 3H-arginine transport, mTOR phosphorylation, and bronchial epithelial repair rates in wound healing assays. To conclude, our study highlights that SLC6A14 genotype might affect lung disease severity of people with cystic fibrosis via mTOR and epithelial repair mechanism modulation in the lung.

Targeting Interleukin-10 Restores Graft Microvascular Supply and Airway Epithelium in Rejecting Allografts.

Interleukin-10 (IL-10) is a vital regulatory cytokine, which plays a constructive role in maintaining immune tolerance during an alloimmune inflammation. Our previous study highlighted that IL-10 mediated immunosuppression established the immune tolerance phase and thereby modulated both microvascular and epithelial integrity, which affected inflammation-associated graft malfunctioning and sub-epithelial fibrosis in rejecting allografts. Here, we further investigated the reparative effects of IL-10 on microvasculature and epithelium in a mouse model of airway transplantation. To investigate the IL-10 mediated microvascular and epithelial repair, we depleted and reconstituted IL-10, and monitored graft microvasculature, airway epithelium, and associated repair proteins. Our data demonstrated that both untreated control allografts and IL-10 (−) allografts showed a significant early (d6) increase in microvascular leakiness, drop-in tissue oxygenation, blood perfusion, and denuded airway epithelium, which is associated with loss of adhesion protein Fascin-1 and β-catenin on vascular endothelial cells at d10 post-transplantation. However, IL-10 (+) promotes early microvascular and airway epithelial repair, and a proportional increase in endothelial Fascin-1, and β-catenin at d10 post-transplantation. Moreover, airway epithelial cells also express a significantly higher expression of FOXJ1 and β-catenin in syngrafts and IL-10 (+) allografts as compared to IL-10 (−) and untreated controls at d10 post-transplantation. Collectively, these findings demonstrated that IL-10 mediated microvascular and epithelial changes are associated with the expression of FOXJ1, β-catenin, and Fascin-1 proteins on the airway epithelial and vascular endothelial cells, respectively. These findings establish a potential reparative modulation of IL-10 associated microvascular and epithelial repair, which could provide a vital therapeutic strategy to facilitate graft repair in clinical settings.

Dysregulated Notch Signaling in the Airway Epithelium of Children with Wheeze.

The airway epithelium of children with wheeze is characterized by defective repair that contributes to disease pathobiology. Dysregulation of developmental processes controlled by Notch has been identified in chronic asthma. However, its role in airway epithelial cells of young children with wheeze, particularly during repair, is yet to be determined. We hypothesized that Notch is dysregulated in primary airway epithelial cells (pAEC) of children with wheeze contributing to defective repair. This study investigated transcriptional and protein expression and function of Notch in pAEC isolated from children with and without wheeze. Primary AEC of children with and without wheeze were found to express all known Notch receptors and ligands, although pAEC from children with wheeze expressed significantly lower NOTCH2 (10-fold, p = 0.004) and higher JAG1 (3.5-fold, p = 0.002) mRNA levels. These dysregulations were maintained in vitro and cultures from children with wheeze displayed altered kinetics of both NOTCH2 and JAG1 expression during repair. Following Notch signaling inhibition, pAEC from children without wheeze failed to repair (wound closure rate of 76.9 ± 3.2%). Overexpression of NOTCH2 in pAEC from children with wheeze failed to rescue epithelial repair following wounding. This study illustrates the involvement of the Notch pathway in airway epithelial wound repair in health and disease, where its dysregulation may contribute to asthma development.