6 research outputs found
ICAM-1 and ICAM-2 Are Differentially Expressed and Up-Regulated on Inflamed Pulmonary Epithelium, but Neither ICAM-2 nor LFA-1: ICAM-1 Are Required for Neutrophil Migration Into the Airways In Vivo
Neutrophil migration into the airways is an important process to fight infection and is mediated by cell adhesion molecules. The intercellular adhesion molecules, ICAM-1 (CD54) and ICAM-2 (CD102) are known ligands for the neutrophil integrins, lymphocyte function associated antigen (LFA)-1 (αLβ2; CD11a/CD18), and macrophage-1 antigen (Mac-1;αMβ2;CD11b/CD18) and are implicated in leukocyte migration into the lung. However, it is ill-defined how neutrophils exit the lung and the role for ICAMs in trans-epithelial migration (TEpM) across the bronchial or alveolar epithelium. We found that human and murine alveolar epithelium expressed ICAM-1, whilst the bronchial epithelium expressed ICAM-2, and both were up-regulated during inflammatory stimulation in vitro and in inflammatory lung diseases such as cystic fibrosis. Although β2 integrins interacting with ICAM-1 and -2 mediated neutrophil migration across human bronchial epithelium in vitro, neither ICAM-2 nor LFA-1 binding of ICAM-1 mediated murine neutrophil migration into the lung or broncho-alveolar space during LPS-induced inflammation in vivo. Furthermore, TEpM of neutrophils themselves resulted in increased epithelial junctional permeability and reduced barrier function in vitro. This suggests that although β2 integrins interacting with ICAMs may regulate low levels of neutrophil traffic in healthy lung or early in inflammation when the epithelial barrier is intact; these interactions may be redundant later in inflammation when epithelial junctions are disrupted and no longer limit TEpM
Effets des macrolides et des glucocorticoïdes sur l'inflammation pulmonaire dans la mucoviscidose
La mucoviscidose (ou CF pour Cystic Fibrosis) est la maladie génétique la plus fréquente en France. Le gène responsable de la maladie code pour un canal chlorure nommé CFTR pour cystic fibrosis transmembrane conductance regulator. La principale cause de décès des patients est liée à l inflammation et aux infections pulmonaires chroniques. Cette inflammation est caractérisée, entre autres, par la production excessive de médiateurs inflammatoires tels que l interleukine (IL)-8. Afin de mieux orienter les stratégies thérapeutiques utilisées actuellement, nous avons étudié les mécanismes moléculaires impliqués dans la réponse anti-inflammatoire des macrolides et des glucocorticoïdes dans des cellules bronchiques CF. Dans un premier temps, nous avons montré que l azithromycine n inhibe pas la sécrétion d'IL-8 dans les cellules CF, et qu elle n a aucun effet sur les voies pro-inflammatoires NF- B et MAPK. De manière intéressante, nous avons démontré que l azithromycine active et restaure les efflux chlorure dans les cellules CF. Dans la seconde partie de notre travail, nous avons mis en évidence que la dexaméthasone inhibe la sécrétion d IL-8 dans les cellules CF, en agissant sur les voies NF- B et MAPK. Nous avons également démontré l effet synergique de la dexaméthasone et d un inhibiteur de p38 MAPK sur la sécrétion d IL-8. L ensemble de ces résultats souligne l importance d étudier précisément les mécanismes moléculaires impliqués dans l inflammation pulmonaire dans la mucoviscidose afin d optimiser les stratégies thérapeutiques pour les patientsPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF
miR-636: A Newly-Identified Actor for the Regulation of Pulmonary Inflammation in Cystic Fibrosis
International audienceCystic fibrosis (CF) results from deficient CF transmembrane conductance regulator (CFTR) protein activity leading to defective epithelial ion transport. Pulmonary degradation due to excessive inflammation is the main cause of morbidity and mortality in CF patients. By analysing miRNAs (small RNAseq) in human primary air-liquid interface cell cultures, we measured the overexpression of miR-636 in CF patients compared to non-CF controls. We validated these results in explant biopsies and determined that the mechanism underlying miR-636 overexpression is linked to inflammation. To identify specific targets, we used bioinformatics analysis to predict whether miR-636 targets the 3 ′-UTR mRNA regions of IL1R1 and RANK (two pro-inflammatory cytokine receptors), IKBKB (a major protein in the NF-κB pathway), and FAM13A (a modifier gene of CF lung phenotype implicated in epithelial remodelling). Using bronchial epithelial cells from CF patients to conduct a functional analysis, we showed a direct interaction between miR-636 and IL1R1, RANK, and IKBKB, but not with FAM13A. These interactions led to a decrease in IL1R1 and IKKβ protein expression levels, while we observed an increase in RANK protein expression levels following the overexpression of miR-636. Moreover, NF-κB activity and IL-8 and IL-6 secretions decreased following the transfection of miR-636 mimics in CF cells. Similar but opposite effects were found after transfection with an antagomiR-636 in the same cells. Furthermore, we demonstrated that miR-636 was not regulated by Pseudomonas aeruginosa in our model. We went on to show that miR-636 is raised in the blood neutrophils, but not in the plasma, of CF patients and may have potential as a novel biomarker. Collectively, our findings reveal a novel actor for the regulation of inflammation in CF, miR-636, which is able to reduce constitutive NF-κB pathway activation when it is overexpressed
Restoration of Chloride Efflux by Azithromycin in Airway Epithelial Cells of Cystic Fibrosis Patients▿
Azithromycin (AZM) has shown promising anti-inflammatory properties in chronic obstructive pulmonary diseases, and clinical studies have presented an improvement in the respiratory condition of cystic fibrosis (CF) patients. The aim of this study was to investigate, in human airway cells, the mechanism by which AZM has beneficial effects in CF. We demonstrated that AZM did not have any anti-inflammatory effect on CF airway cells but restored Cl− efflux
Azithromycin fails to reduce inflammation in cystic fibrosis airway epithelial cells
Cystic fibrosis is a hereditary disease caused by a mutation in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene that encodes a chloride (a) channel. Cystic fibrosis pulmonary pathophysiology is characterised by chronic inflammation and bacterial infections. Azithromycin, a macrolide antibiotic, has shown promising anti-inflammatory properties in some inflammatory pulmonary diseases. Moreover, all clinical studies have presented an improvement of the respiratory condition of cystic fibrosis patients, but the molecular and cellular mechanisms remain unknown. The aim of this study was to investigate, in bronchial epithelial cells, the effects of azithromycin on inflammatory pathways involved in cystic fibrosis. We have analysed the effects of azithromycin on cystic fibrosis and non-cystic fibrosis bronchial epithelial cell lines but also in non-immortalized non-cystic fibrosis human glandular cells. To create an inflammatory context, cells were treated with Tumor Necrosis Factor (TNF)-alpha or Interleukin (IL)1-beta. Activation of the NF-kappa B pathway was investigated by luciferase assay, western blotting, and by Forster Resonance Energy Transfer imaging, allowing the detection of the interaction between the transcription factor and its inhibitor in live cells. In all conditions tested, azithromycin did not have an anti-inflammatory effect on the cystic fibrosis human bronchial epithelial cells and on CFTR-inhibited primary human bronchial glandular cells. More, our data showed no effect of azithromycin on IL-1 beta- or TNF-alpha-induced IL-8 secretion and NF-kappa B pathway activation. Taken together, these data show that azithromycin is unable to decrease in vitro inflammation in cystic fibrosis cells from airway
Opposite expression of hepatic and pulmonary corticosteroid-binding globulin in cystic fibrosis patients
International audienceCystic fibrosis (CF) is characterized by a chronic pulmonary inflammation. In CF, glucocorticoids (GC) are widely used, but their efficacy and benefit/risk ratio are still debated. In plasma, corticosteroid-binding globulin (CBG) binds 90% of GC and delivers them to the inflammatory site. The main goal of this work was to study CBG expression in CF patients in order to determine whether CBG could be used to optimize GC treatment. The expression of CBG was measured in liver samples from CF cirrhotic and non-CF cirrhotic patients by qPCR and Western blot and in lung samples from non-CF and CF patients by qPCR. CBG binding assays with H-3-cortisol and the measurement of the elastase/alpha 1-antitrypsin complex were performed using the plasmas. CBG expression increased in the liver at the transcript and protein level but not in the plasma of CF patients. This is possibly due to an increase of plasmatic elastase. We demonstrated that pulmonary CBG was expressed in the bronchi and bronchioles and its expression decreased in the CF lungs, at both levels studied. Despite the opposite expression of hepatic and pulmonary CBG in CF patients, the concentration of CBG in the plasma was normal. Thus, CBG might be useful to deliver an optimized synthetic GC displaying high affinity for CBG to the main inflammatory site in the context of CF, e.g., the lung