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KIT is a receptor tyrosine kinase that after binding to its ligand stem cell factor activates signaling cascades linked to biological processes such as proliferation, differentiation, migration and cell survival. Based on studies performed on SCF and/or KIT mutant animals that presented anemia, sterility, and/or pigmentation disorders, KIT signaling was mainly considered to be involved in the regulation of hematopoiesis, gametogenesis, and melanogenesis. More recently, novel animal models and ameliorated cellular and molecular techniques have led to the discovery of a widen repertoire of tissue compartments and functions that are being modulated by KIT. This is the case for the lung, heart, nervous system, gastrointestinal tract, pancreas, kidney, liver, and bone. For this reason, the tyrosine kinase inhibitors that were originally developed for the treatment of hemato-oncological diseases are being currently investigated for the treatment of non-oncological disorders such as asthma, rheumatoid arthritis, and alzheimer's disease, among others. The beneficial effects of some of these tyrosine kinase inhibitors have been proven to depend on KIT inhibition. This review will focus on KIT expression and regulation in healthy and pathologic conditions other than cancer. Moreover, advances in the development of anti-KIT therapies, including tyrosine kinase inhibitors, and their application will be discussed. [ABSTRACT FROM AUTHOR]

The article discusses a study on the effect of club cell secretory protein (CCSP) as a therapeutic strategy to restore the balance between injury and repair in chronic obstructive pulmonary disease (COPD). Topics covered include the method for obtaining endobronchial biopsy specimens, the findings of the morphometric analysis of the initial EBB, and the potential use of exogenous recombinant human CCSP (rhCCSP) exogenous supplementation for COPD patients.

Abstract: Increasing evidence of a critical role played by the bronchial epithelium in airway homeostasis is opening new therapeutic avenues. Its unique situation at the interface with the environment suggests that the subtle regulation orchestrated by the epithelium between tolerance and specific immune response might be impaired in asthma. Airway mucus is acting as a physical and a biological fluid between the environment and the epithelium, synergistically moved by the cilia. In asthma, excessive mucus production is a hallmark of airway remodeling. Since many years we tried to therapeutically target mucus hypersecretion, but actually this option is still not achieved. The present review discusses the dynamic processes regulating airway mucus production. Airway inflammation is central in current asthma management. Understanding of how the airway epithelium influences the TH2 paradigm in response to deleterious agents is improving. The multiple receptors expressed by the airway epithelium are the transducers of the biological signals induced by various invasive agents to develop the most adapted response. Airway remodeling is observed in severe chronic airway diseases and may result from ongoing disturbance of signal transduction and epithelial renewal. Chronic airway diseases such as asthma will require assessment of these epithelial abnormalities to identify phenotypic characteristics associated with predicting a clinical benefit for epithelial-directed therapies. [Copyright &y& Elsevier]

Background: Severe asthma is characterized by neutrophilic inflammation and high levels of interleukin (IL)-8. Airway epithelial cells play a pivotal role in the pathogenesis and chronicity of asthma. The objective of this work was to determine whether CXC receptors were involved in human small airway epithelial cell (SAEC) activity by incubating them with IL-8; the investigation also included a proteomic approach. Methods: IL-6 and intercellular adhesion molecule-1 (ICAM-1) were assessed by ELISA and flow cytometry, respectively. CXCR-1 and CXCR-2 receptor mRNA and protein expressions were analyzed by RT-PCR, immunocytochemistry and flow cytometry. Cells were incubated with different concentrations (0–100 ng/ml) of IL-8. The involvement of both receptors was assessed using specific antibodies. Results: Only the CXCR-1 receptor was expressed in SAECs. IL-8 (50 ng/ml, 12 h) induced the release of IL-6 and had no effect on ICAM-1. Supernatants analyzed by surface enhanced laser desorption ionization time of flight mass spectrometry (SELDI-TOF MS) showed very weak differences in peptide profiles. Interestingly, 4,820-m/z peptide release was detected in the presence of IL-8 and abolished by CXCR-1 antibody. Discussion: The present study illustrated the fact that IL-8 mediated by CXCR-1 increased IL-6. We also highlight the usefulness of SELDI ProteinChip technology to confirm the potential variation of peptide profile. Moreover, we were able to detect the 4,820-m/z peptide secreted in vitro by human airway epithelial cells induced by IL-8 via CXCR-1 receptor. Determination of the protein secretion profile in response to inflammatory stimuli could be an important therapeutic strategy in severe asthma. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Gras D, Chanez P, Urbach V, Vachier I, Godard P, Bonnans C. Thiazolidinediones induce proliferation of human bronchial epithelial cells through the GPR4O receptor. Am J Physiol Lung Cell Mol Physiol 296: L970-L978, 2009. First published April 3, 2009; doi: 10.1152/ajplung.90219.2008.-Thiazolidinediones (TZDs) are synthetic peroxisome proliferator-activated receptor-γ (PPARγ) ligands that are widely used in type 11 diabetes treatment. In addition to their ability to improve glucose homeostasis, TZDs possess antiinflammatory properties and inhibit growth of many cells, particularly cancerous airway epithelial cells. However, the functional effects of PPARγ ligands on nonmalignant human bronchial epithelial cells have never been investigated. In the present study, we questioned whether PPAR-γ ligands may regulate proliferation of human bronchial epithelial cells, and we studied their potential molecular mechanisms. We found that synthetic PPAR-γ agonists, rosiglitazone (RGZ) and troglitazone (TGZ), induced proliferation of human bronchial epithelial cells, whereas the endogenous PPARγ ligand, 15deoxy-Δ[sup12.14]-prostaglandin J[sub2] (15d-PGJ[sub2]), inhibited cell growth. RGZ and TGZ (10 μM) induced a rapid and transient intracellular Ca[sup2+] mobilization from thapsigargin-sensitive intracellular stores, whereas lsd-PGJ[sub2] (5 μM) did not induce any Ca[sup2+] signal. The PPARγ antagonist GW-9662 did not inhibit any biological responses, but it reversed the effect of 15d-PGJ[sub2] on cell growth. Using RT-PCR, we detected mRNA expression of the GPR4O receptor, a G proteincoupled receptor recently identified as a receptor for free fatty acids and TZDs, in human bronchial epithelial cells. Downregulation of GPR4O by small-interfering RNA led to a significant inhibition of TZD-induced Ca[sup2+] mobilization and proliferation. This study provides evidence for the proliferative effect of anti-diabetic drug TZDs in nonmalignant human bronchial epithelial cells through GPR40 receptor activation, involving an intracellular Ca[sup2+] signaling pathway. [ABSTRACT FROM AUTHOR]

Abstract: In this study, we investigated the synthesis of lipoxins (LXs) and their anti-inflammatory effects in different human airway epithelial cell culture models. After cell incubation with exogenous 5(S),6(R)-dihydroxy-7,9-trans-11,14-cis-eicosatetraenoic acid, LXA4 was detected in supernatants of differentiated human bronchial epithelial cells by contrast to non-differentiated cells. Exogenous LXA4 significantly inhibited tumor necrosis factor-α (TNF-α)-induced interleukin-8 (IL-8) release in the different epithelial cell types and the potency of inhibition was dependent of the accessibility of the specific LXA4 receptor, formyl-peptide receptor like-1 (FPRL-1) expressed by all these cells. Immunohistochemistry analysis on human bronchial biopsies showed a high expression of FPRL-1 in the epithelium. Finally, an FPRL-1 receptor antagonist, boc-2 peptide reversed LXA4 effect on IL-8 generation. Together, these findings indicate that differentiated human bronchial epithelium synthesizes LX in vivo which could have autocrine actions through its specific receptor FPRL-1 to promote resolution of airway inflammation. [Copyright &y& Elsevier]

Uncontrolled inflammation of the airways in chronic obstructive lung diseases leads to exacerbation, accelerated lung dysfunction and respiratory insufficiency. Among these diseases, asthma affects 358 million people worldwide. Human bronchial epithelium cells (HBEC) express both anti‐inflammatory and activating molecules, and their deregulated expression contribute to immune cell recruitment and activation, especially platelets (PLT) particularly involved in lung tissue inflammation in asthma context. Previous results supported that HLA‐G dysregulation in lung tissue is associated with immune cell activation. We investigated here HLA‐F expression, reported to be mobilised on immune cell surface upon activation and displaying its highest affinity for the KIR3DS1‐activating NK receptor. We explored HLA‐F transcriptional expression in HBEC; HLA‐F total expression in PBMC and HBEC collected from healthy individuals at rest and upon chemical activation and HLA‐F membrane expression in PBMC, HBEC and PLT collected from healthy individuals at rest and upon chemical activation. We compared HLA‐F transcriptional expression in HBEC from healthy individuals and asthmatic patients and its surface expression in HBEC and PLT from healthy individuals and asthmatic patients. Our results support that HLA‐F is expressed by HBEC and PLT under healthy physiological conditions and is retained in cytoplasm, barely expressed on the surface, as previously reported in immune cells. In both cell types, HLA‐F reaches the surface in the inflammatory asthma context whereas no effect is observed at the transcriptional level. Our study suggests that HLA‐F surface expression is a ubiquitous post‐transcriptional process in activated cells. It may be of therapeutic interest in controlling lung inflammation. [ABSTRACT FROM AUTHOR]

As opposed to surface marker staining, certain cell types can only be recognized by intracellular markers. Intracellular staining for use in cell sorting remains challenging. Fixation and permeabilization steps for intracellular staining and the presence of RNases notably affect preservation of high-quality mRNA. We report the work required for the optimization of a successful protocol for microarray analysis of intracellular target-sorted, formalin-fixed human bronchial club cells. Cells obtained from differentiated air-liquid interface cultures were stained with the most characteristic intracellular markers for club cell (SCGB1A1+) sorting. A benchmarked intracellular staining protocol was carried out before flow cytometry. The primary outcome was the extraction of RNA sufficient quality for microarray analysis as assessed by Bioanalyzer System. Fixation with 4% paraformaldehyde coupled with 0.1% Triton/0.1% saponin permeabilization obtained optimal results for SCGB1A1 staining. Addition of RNase inhibitors throughout the protocol and within the appropriate RNA extraction kit (Formalin-Fixed-Paraffin-Embedded) dramatically improved RNA quality, resulting in samples eligible for microarray analysis. The protocol resulted in successful cell sorting according to specific club cell intracellular marker without using cell surface marker. The protocol also preserved RNA of sufficient quality for subsequent microarray transcriptomic analysis, and we were able to generate transcriptomic signature of club cells. • Successful SCGB1A1 sorting according to specific intracellular marker. • Preserved RNA of sufficient quantity and quality for microarray experiment. • Pathways underlying both mucus production and ciliogenesis in SCGB1A1+ cells. • Signature of basal cells for SCGB1A1- cells. [ABSTRACT FROM AUTHOR]

Platelets are small anucleate cells derived from the fragmentation of megakaryocytes and are involved in different biological processes especially hemostasis, thrombosis, and immune response. Despite their lack of nucleus, platelets contain a reservoir of megakaryocyte-derived RNAs and all the machinery useful for mRNA translation. Interestingly, platelet transcriptome was analyzed in health and diseases and led to the identification of disease-specific molecular signatures. Platelet contamination by leukocytes and erythrocytes during platelet purification is a major problem in transcriptomic analysis and the presence of few contaminants in platelet preparation could strongly alter transcriptome results. Since contaminant impacts on platelet transcriptome remains theoretical, we aimed to determine whether low leukocyte and erythrocyte contamination could cause great or only minor changes in platelet transcriptome. Using microarray technique, we compared the transcriptome of platelets from the same donor, purified by common centrifugation method or using magnetic microbeads to eliminate contaminating cells. We found that platelet transcriptome was greatly altered by contaminants, as the relative amount of 8274 transcripts was different between compared samples. We observed an increase of transcripts related to leukocytes and erythrocytes in platelet purified without microbeads, while platelet specific transcripts were falsely reduced. In conclusion, serious precautions should be taken during platelet purification process for transcriptomic analysis, in order to avoid platelets contamination and result alteration. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus is a major cause of pulmonary infection, particularly in cystic fibrosis (CF) patients. However, few aspects of the interplay between S. aureus and host airway epithelial cells have been investigated thus far. We investigated by videomicroscopy the time- and bacterial concentration-dependent (104 , 106, and 108 CFU/ml) effect of S. aureus on adherence, internalization, and the associated damage of the airway epithelial cells. The balance between the secretion by S. aureus of the α-toxin virulence factor and by the airway cells of the antibacterial secretory leukoproteinase inhibitor (SLPI) was also analyzed. After 1 h of interaction, whatever the initial bacterial concentration, a low percentage of S. aureus (<8%) adhered to airway cells, and no airway epithelial cell damage was observed. In contrast, after 24 h of incubation, more bacteria adhered to airway epithelial cells, internalized bacteria were observed, and a bacterial concentration-dependent effect on airway cell damage was observed. At 24 h, most airway cells incubated with bacteria at 108 CFU/ml exhibited a necrotic phenotype. The necrosis was preceded by a transient apoptotic process. In parallel, we observed a time- and bacterial concentration-dependent decrease in SLPI and increase in α-toxin expression. These results suggest that airway cells can defend against S. aureus in the early stages of infection. However, in later phases, there is a marked imbalance between the bactericidal capacity of host cells and bacterial virulence. These findings reinforce the potential importance of S. aureus in the pathogenicity of airway infections, including those observed early in CF patients. [ABSTRACT FROM AUTHOR]

Purpose: Asthma exacerbations are inflammatory events that rarely result in full hospitalization following an ER visit. Unfortunately, certain patients require prolonged support, including occasional external lung support through ECMO or ECCOR (with subsequent further exposure to other life‐threatening issues), and some die. In parallel, biologics are revolutionizing severe asthma management, mostly in T2 high patients. Methods: We extensively reviewed the current unmet needs surrounding ICU‐admitted asthma exacerbations, with a focus on currently available drugs and the underlying biological processes involved. We explored whether currently available T2‐targeting drugs can reasonably be seen as potential players not only for relapse prevention but also as candidate drugs for a faster resolution of such episodes. The patient's perspective was also sought. Results: About 30% of asthma exacerbations admitted to the ICU do not resolve within five days. Persistent severe airway obstruction despite massive doses of corticosteroids and maximal pharmacologically induced bronchodilation is the main cause of treatment failure. Previous ICU admission is the main risk factor for such episodes and may eventually be considered as a T2 surrogate marker. Fatal asthma cases are hallmarked by poorly steroid‐sensitive T2‐inflammation associated with severe mucus plugging. New, fast‐acting T2‐targeting biologics (already used for preventing asthma exacerbations) have the potential to circumvent steroid sensitivity pathways and decrease mucus plugging. This unmet need was confirmed by patients who reported highly negative, traumatizing experiences. Conclusions: There is room for improvement in the management of ICU‐admitted severe asthma episodes. Clinical trials assessing how biologics might improve ICU outcomes are direly needed. [ABSTRACT FROM AUTHOR]

Summary: Background: Goblet cell hyperplasia (GCH) is a pathological finding classically reported across asthma severity levels and usually associated with smoking. Multiple biological mechanisms may contribute to excessive mucus production. Objective: We aimed to decipher the clinical meanings and biological pathways related to GCH in non‐smokers with asthma. Methods: Cough and sputum assessment questionnaire (CASA‐Q) responses at entry and 1 year later were compared to clinical and functional outcomes in 59 asthmatic patients. GCH was assessed through periodic‐acid shift (PAS) staining on endobronchial biopsies obtained at entry in a subset of 32 patients. Results: Periodic‐acid shift‐staining analysis revealed a double wave distribution discriminating patients with (>10% of the epithelial area) or without GCH. CASA‐Q scores were mostly driven by overall asthma severity (P < 0.0001). CASA‐Q scores remained stable at 1 year and were independently associated with BAL eosinophil content irrespective of the presence of GCH. GCH was unrelated to the presence of bronchiectasis at CT, GERD or chronic rhinosinusitis, but correlated well with neutrophilic inflammatory patterns observed upon BAL cellular analysis (P = 0.002 at multivariate analysis). BALF bacterial loads were unrelated to GCH or to CASA‐Q. Conclusions and Clinical Relevance: Goblet cell hyperplasia is disconnected from chronic cough and sputum when assessed by a specific questionnaire. GCH is related to neutrophilic asthma whereas symptoms are related to airway eosinophilia. The clinical counterpart of GCH is unlikely assessed by the CASA‐Q. [ABSTRACT FROM AUTHOR]

Lungs have a complex structure composed of different cell types that form approximately 17 million airway branches of gas-delivering bronchioles connected to 500 million gas-exchanging alveoli. Airways and alveoli are lined by epithelial cells that display a low rate of turnover at steady-state, but can regenerate the epithelium in response to injuries. Here, we review the key points of lung development, homeostasis and epithelial cell plasticity in response to injury and disease, because this knowledge is required to develop new lung disease treatments. Of note, canonical signaling pathways that are essential for proper lung development during embryogenesis are also involved in the pathophysiology of most chronic airway diseases. Moreover, the perfect control of these interconnected pathways is needed for the successful differentiation of induced pluripotent stem cells (iPSC) into lung cells. Indeed, differentiation of iPSC into airway epithelium and alveoli is based on the use of biomimetics of normal embryonic and fetal lung development. In vitro iPSC-based models of lung diseases can help us to better understand the impaired lung repair capacity and to identify new therapeutic targets and new approaches, such as lung cell therapy. [ABSTRACT FROM AUTHOR]

Growing up on a dairy farm protects children from allergy, hay fever, and asthma. A mechanism linking exposure to this endotoxin (bacterial lipopolysaccharide)-rich environment with protection has remained elusive. Here we show that chronic exposure to low-dose endotoxin or farm dust protects mice from developing house dust mite (HDM)-induced asthma. Endotoxin reduced epithelial cell cytokines that activate dendritic cells (DCs), thus suppressing type 2 immunity to HDMs. Loss of the ubiquitin-modifying enzyme A20 in lung epithelium abolished the protective effect. A single-nucleotide polymorphism in the gene encoding A20 was associated with allergy and asthma risk in children growing up on farms. Thus, the farming environment protects from allergy by modifying the communication between barrier epithelial cells and DCs through A20 induction. [ABSTRACT FROM AUTHOR]

The airway epithelium is a dynamic tissue that undergoes slow but constant renewal. Dysregulation of airway epithelial function related to cigarette smoke exposure plays an important role in the pathophysiology of COPD. Oct4 is a transcription factor responsible for maintaining cellular self-renewal and regeneration, and CD146 and CD105/Endoglin are adhesion molecules involved in cell proliferation, differentiation, epithelial-mesenchymal-transition and tissue remodeling. Bronchial biopsy specimens (BBs) were obtained from 7 healthy controls (HC) and 10 COPD and subjected to paraffin embedding; BBs from HC were also used for epithelial cell expansion and pHBEC/ALI (air-liquid interface) culture. pHBEC/ALI were exposed to cigarette smoke extract (CSE) for 7, 14 and 21 days. In BBs, Oct4, CD146 and CD105 were evaluated by immunohistochemistry. In pHBEC/ALI, the expression of Oct4, CD146, CD105 and acetyl-αtubulin was evaluated by Western Blot, MUC5AC and IL-8 measurements by ELISA. The Oct4 epithelial immunoreactivity was lower in COPD than in HC, whilst CD146 and CD105 expression was higher in COPD than in HC. In pHBEC/ALI, Transepithelial Electrical Resistance values, measured over 7 to 21 days of differentiation, decreased by 18% (2.5% CSE) and 29% (5% CSE) compared to untreated samples. Oct4 and acetyl-αtubulin were induced after one-week differentiation and downregulated by CSE in reconstituted epithelium; CD146, CD105, MUC5AC and IL-8 were increased by CSE. Oct4 de-regulation and CD146 and CD105 overexpression, induced by cigarette smoke exposure, might play a role in airway epithelial dysfunction by causing changes in self-renewal and mesenchymal transition mechanisms, leading to alteration of epithelium homeostasis and abnormal tissue remodeling involved in progression of COPD. • Oxidative-stress mediated mechanisms induce de-regulation of Oct4 protein expression. • De-regulation of Oct4, might play a role in reorientation of lung epithelium self-renewal process. • Overexpressio of CD146 and CD105 mesenchimal markers is associated with de-differentiation and EMT. • Altered Oct4 regulation and CD146 and CD105 expression are potentially involved in lack of lung epithelium homeostasis and abnormal tissue remodeling in COPD. [ABSTRACT FROM AUTHOR]

To cite this article: Belhocine W, Ibrahim Z, Grandné V, Buffat C, Robert P, Gras D, Cleach I, Bongrand P, Carayon P, Vitte J. Total serum tryptase levels are higher in young infants. Pediatr Allergy Immunol 2011; 22: 600-607. Abstract Background: Mast cells participate in immune defense and allergic disease. At baseline, serum tryptase levels primarily reflect mast cell burden, while mast cell degranulation leads to granule tryptase release, which may be detectable as a transitory elevation of serum tryptase levels. Thus, mast cell burden and mast cell activity are reflected by serum tryptase levels, but reports are scarce in infants under 1 yr. We aimed at defining levels of total serum tryptase levels in this population. Methods: Total serum tryptase levels (ImmunoCAP; Phadia) were measured in 372 sera from infants younger than 1 yr. Two hundred and forty-two sera came from non-atopic, non-allergic infants in good condition, who had blood drawn for routine follow-up or diagnosis of illnesses that are not known to induce changes in serum tryptase levels. Seventy-two sera were from atopic and/or allergic infants, and 58 sera were from non-atopic, non-allergic infants requiring intensive care. Results: Median serum tryptase levels were highest in infant2s under 3 months (6.12 ± 3.47 μg/l) and gradually decreased before reaching levels similar to those described in adults and older children (3.85 ± 1.8 μg/l between 9 and 12 months). Atopic/allergic status was associated with even higher tryptase levels (14.20 ± 10.22 μg/l in infants younger than 3 months). Intensive care patients had lower levels of serum tryptase (4.12 ± 3.38 μg/l in infants younger than 3 months). Longitudinal follow-up was performed in 27 patients and showed tryptase levels decrease over time in individual patients. Infants'sex was not found to interfere with serum tryptase levels. Conclusion: Total serum tryptase levels are significantly higher in younger infants compared with older ones. In infants of the same age, serum tryptase levels may vary according to the clinical condition and thus suggest mast cell involvement in the physiologic as well as in the allergic immune responses of young infants. [ABSTRACT FROM AUTHOR]

Estrogens are mitogenic in human breast cancer cells, but the presence of estrogen receptor α (ERα) is associated with a favorable prognosis in primary tumors and the molecular basis for this paradoxical relationship remains unknown. Here we show that ERα and ERα mutants devoid of ligand and DNA-binding domains inhibit cell growth in three-dimensional matrix as well as tumor formation in nude mice. Using in vitro and intracellular approaches, we have found that ERα, via its amino acids 184-283, interacts with cyclin-dependent kinase inhibitor p21WAF1. Both proteins exhibit mutual interactions in the absence of estrogens or in the presence of pure antiestrogen ICI182,780, whereas estradiol treatment disrupts their interactions. Cross-linking experiments reveal that these proteins are present in a larger complex of ~200 kDa that also contains cdk2 and cyclin E. We further demonstrate that the unliganded full-length ERα or the variant having the p21WAF1 interaction region significantly increases p21WAF1 expression, whereas ERα silencing reduces p21WAF1 levels and silencing of p21WAF1 is sufficient to prevent ERα-induced growth inhibition. Taken together, our results point to an antiproliferative function of the unliganded ERα through its physical interactions with p21WAF1 that may also explain the favorable prognosis of ERα-positive breast cancers. [ABSTRACT FROM AUTHOR]

A summary is presented of an article published online at http://dx.doi.org/10.1126/science.aaw4295 on the role of Charcot-Ledyen crystals (CLCs) in airway disease and type 2 immunity which found activated eosinophils result in the release of galectin-10 proteins which enter a crystalline state which actively promotes asthma symptoms.