Feasibility of nasal epithelial brushing for the study of airway epithelial functions in CF infants.

Background: For a better understanding of the early stages of cystic fibrosis (CF), it is of major interest to study respiratory epithelial cells obtained as early as possible. Although bronchoalveolar lavage has been proposed for this purpose, nasal brushing, which is a much less invasive technique, has seldom been used in CF infants. The aim of the present study was to examine in a few infants the feasibility of a nasal brushing technique for studies of airway epithelial functions in very young CF infants.

Airway epithelial repair, regeneration, and remodeling after injury in chronic obstructive pulmonary disease.

In chronic obstructive pulmonary disease (COPD), exacerbations are generally associated with several causes, including pollutants, viruses, bacteria that are responsible for an excess of inflammatory mediators, and proinflammatory cytokines released by activated epithelial and inflammatory cells. The normal response of the airway surface epithelium to injury includes a succession of cellular events, varying from the loss of the surface epithelium integrity to partial shedding of the epithelium or even complete denudation of the basement membrane. The epithelium then has to repair and regenerate to restore its functions, through several mechanisms, including basal cell spreading and migration, followed by proliferation and differentiation of epithelial cells.

Trefoil factor family 3 peptide promotes human airway epithelial ciliated cell differentiation.

Human airway surface epithelium is frequently damaged by inhaled factors (viruses, bacteria, xenobiotic substances) as well as by inflammatory mediators that contribute to the shedding of surface epithelial cells. To regain its protective function, the epithelium must rapidly repair and redifferentiate. The Trefoil Factor Family (TFF) peptides are secretory products of many mucous cells.

Basal cells of the human adult airway surface epithelium retain transit-amplifying cell properties.

In numerous airway diseases, such as cystic fibrosis, the epithelium is severely damaged and must regenerate to restore its defense functions. Although the human airway epithelial stem cells have not been identified yet, we have suggested recently that epithelial stem/progenitor cells exist among both human fetal basal and suprabasal cell subsets in the tracheal epithelium. In this study, we analyzed the capacity of human adult basal cells isolated from human adult airway tissues to restore a well-differentiated and functional airway epithelium.

Downregulation by a long-acting beta2-adrenergic receptor agonist and corticosteroid of Staphylococcus aureus-induced airway epithelial inflammatory mediator production.

Although Staphylococcus aureus is a major cause of pulmonary infection, the role played by this bacterium in the induction of inflammation of human airway epithelial cells (HAEC) is poorly understood. In this study, we investigated the inflammatory response of HAEC to S. aureus soluble virulence factors and demonstrate that the combination of a long-acting beta2-adrenergic receptor agonist (salmeterol) with a glucocorticoid (fluticasone propionate) has an anti-inflammatory effect on HAEC.

[Repair and regeneration of the airway epithelium].

Despite an efficient defence system, the airway surface epithelium, in permanent contact with the external milieu, is frequently injured by inhaled pollutants, microorganisms and viruses. The response of the airway surface epithelium to an acute injury includes a succession of cellular events varying from the loss of the surface epithelium integrity to partial shedding of the epithelium or even to complete denudation of the basement membrane. The epithelium has then to repair and regenerate to restore its functions, through several mechanisms including basal cell spreading and migration, followed by proliferation and differentiation of epithelial cells.

T cell chemotaxis and chemokine release after Staphylococcus aureus interaction with polarized airway epithelium.

In response to bacterial infection, airway epithelium releases inflammatory mediators including cytokines and chemokines that lead to immune cell efflux and could stimulate the adaptive T cell immune response. The aim of our study was to analyze, in a double chamber culture, the chemokine changes in response to Staphylococcus aureus and their consequences for T cells. Our data show that S.

Aquaporin-3 expression in human fetal airway epithelial progenitor cells.

Airway epithelium stem cells have not yet been prospectively identified, but it is generally assumed that both secretory and basal cells have the capacity to divide and differentiate. Previously, we developed a test for progenitor cells of the human airway epithelium, relying on the transplantation of fetal respiratory tissues into immunodeficient mice. In this study, we hypothesized that airway-repopulating epithelial progenitors can be marked with surface antigens, and we screened an array of such candidate markers, including lectin ligands, the CD44 and CD166 adhesion molecules, and the aquaporin-3 (AQP3) water channel.

Differential expression of matrix metalloproteinases and interleukin-8 during regeneration of human airway epithelium in vivo.

In many airway diseases, the airway epithelium is severely damaged and has to regenerate rapidly to restore its function. The regeneration process involves chronological steps of epithelial cell migration, proliferation, stratification, and differentiation. The present study has used an in vivo humanized airway xenograft model in nude mice that mimics the regeneration dynamics of human airway epithelium after severe injury, and human-specific molecular tools, to study the expression profiles of epithelial matrix metalloproteinases (MMPs)-7 and -9, of tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), and of the pro-inflammatory cytokine interleukin-8 (IL-8) during the different steps of human airway epithelium regeneration.

Live Staphylococcus aureus and bacterial soluble factors induce different transcriptional responses in human airway cells.

To characterize the response of respiratory epithelium to infection by Staphylococcus aureus (S. aureus), human airway cells were incubated for 1 to 24 h with a supernatant of a S. aureus culture (bacterial supernatant), then profiled with a pangenomic DNA microarray.

Embryonic stem cells generate airway epithelial tissue.

Embryonic stem (ES) cells are self-renewable and pluripotent cells derived from the inner cell mass of a blastocyst-stage embryo. ES cell pluripotency is being investigated increasingly to obtain specific cell lineages for therapeutic treatments and tissue engineering. Type II alveolar epithelial cells have been derived from murine ES cells, but the capacity of the latter to generate differentiated airway epithelial tissue has never been reported.

Antibodies for CFTR studies.

For most expression studies focusing on the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein, sensitive and specific antibodies (Abs) are critically needed. Several Abs have been produced commercially or by research laboratories for CFTR detection in both cell lines with heterologous or endogenous expression and native cells/tissues. Here, we review the applicability of most Abs currently in use in CF research for the biochemical and/or immunocytochemical detection of CFTR.

Reconstitution of human airway tissue in the humanized xenograft model.

Normal human airway epithelial tissue may be reconstituted in the humanized xenograft model in immunodeficient NUDE mice. Epithelial cells dissociated from human fetal or adult tissue are seeded on a denuded rat trachea and implanted in the NUDE mice. After a first step of dedifferentiation, the human epithelial cells adhere on the denuded basal lamina of the rat host trachea and progressively reconstitute a normal well-differentiated epithelium after several steps of migration, proliferation, stratification and redifferentiation.

Immunohistochemistry of CFTR in native tissues and primary epithelial cell cultures.

Studies on CFTR protein expression and localization in native tissues or in primary cultures of human epithelial cells are scarce due to the intrinsic instability of this protein, its low expression in most tissues and also to technical difficulties. However, such data are of the highest importance to understand the pathophysiology of CF. The purpose of this article is to outline several assays for the characterization of primary epithelial cultures and to review different CFTR immunostaining protocols.

Regeneration of a well-differentiated human airway surface epithelium by spheroid and lentivirus vector-transduced airway cells.

Background: Following injury to the airway epithelium, rapid regeneration of a functional epithelium is necessary in order to restore the epithelial barrier integrity. In the perspective of airway gene/cell therapy, we analyzed the capacity of human airway epithelial cells cultured as three-dimensional (3-D) spheroid structures to be efficiently transduced on long term by a pseudotyped lentiviral vector. The capacity of the 3-D spheroid structures to repopulate a denuded tracheal basement membrane and regenerate a well-differentiated airway epithelium was also analyzed.

Dynamic interaction between airway epithelial cells and Staphylococcus aureus.

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.

Airway epithelial integrity is protected by a long-acting beta2-adrenergic receptor agonist.

Airway epithelial integrity may be impaired by bacterial exoproducts, which are able to degrade tight junction-associated proteins such as zonula occludens 1 (ZO-1). We have investigated the protective effect of salmeterol, a long-acting beta(2)-adrenergic agonist, on Pseudomonas aeruginosa-induced alteration of the epithelial junctional barrier. We demonstrate in human airway epithelial cells (HAEC) that salmeterol induces a time-dependent increase in ZO-1 protein, although no significant change in ZO-1 transcripts was observed.

E-Cadherin mediates MMP down-regulation in highly invasive bronchial tumor cells.

The disorganization of E-cadherin/catenin complexes and the overexpression of matrix metalloproteinases (MMPs) are frequently involved in the capacity of epithelial cells to acquire an invasive phenotype. The functional link between E-cadherin and MMPs was studied by transfecting invasive bronchial BZR tumor cells with human E-cadherin cDNA. Using different in vitro (cell dispersion, modified Boyden chamber) and in vivo assays (human airway epithelial xenograft), we showed that E-cadherin-positive clones displayed a decrease of invasive abilities.

Chronology of cellular alterations during 7-ketocholesterol-induced cell death on A7R5 rat smooth muscle cells: analysis by time lapse-video microscopy and conventional fluorescence microscopy.

Background: Time-lapse video microscopy was used to determine whether mitochondrial and nuclear changes (decrease in mitochondrial transmembrane potential, condensation, and/or fragmentation of the nuclei, morphologic features typical of apoptosis) occurring during 7-ketocholesterol-induced cell death on A7R5 rat smooth muscle cells took place before or after the loss of cell adhesion. In addition, changes in actin organization were followed by conventional fluorescence microscopy.

Methods: Morphologic, functional, and spatial changes at the mitochondrial level were investigated with 3,3'-dihexyloxacarbocyanine iodide and/or MitoTracker Red, and nuclear morphology was characterized by staining with Hoechst 33342.

Stimulation of beta 2-adrenergic receptor increases cystic fibrosis transmembrane conductance regulator expression in human airway epithelial cells through a cAMP/protein kinase A-independent pathway.

PSD-95/Dlg-A/ZO-1 (PDZ) domains play an essential role in determining cell polarity. The Na(+)/H(+) exchanger regulatory factor (NHERF), also known as EBP50, contains two PDZ domains that mediate the assembly of transmembrane and cytosolic proteins into functional signal transduction complexes. Moreover, it has been shown that cystic fibrosis transmembrane conductance regulator (CFTR) and beta(2)-adrenergic receptor (beta(2)AR) bind equally well to the PDZ1 domain of EBP50.

Characterization of ion and fluid transport in human bronchioles.

The regulation of the volume and composition of airway surface liquid is achieved through epithelial ion transport processes. In humans, these processes have been characterized in proximal but not distal airways. Segments of human bronchioles were dissected from surgically removed lung pieces.

Airway mucus in cystic fibrosis.

Defective expression and function of the cystic fibrosis transmembrane conductance regulator (CFTR) in cystic fibrosis (CF) airway epithelial cells are associated with airway mucus hypersecretion, inflammation and infection that begin early in life and lead, at an advanced stage of the disease, to severe airway obstruction with hyperviscous and adhesive airway mucus. Whether the abnormalities of airway mucus are already present at birth before infection is debatable. In CF, the impaired Cl(-) and HCO(3)(-) secretion associated with increased epithelial Na(+) absorption results in dehydration of airway mucus, decreased antimicrobial functions and impaired mucociliary clearance.

Distribution of laminin 5, integrin receptors, and branching morphogenesis during human fetal lung development.

The role of the epithelial adhesion ligand laminin 5 (LN5) in lung development has been poorly investigated. To determine its potential involvement in lung organogenesis, we used immunofluorescence microscopy to investigate the distribution of LN5 and its integrin (Int) receptors alpha2beta1, alpha3beta1, alpha6beta1, and alpha6beta4 during human fetal airway branching morphogenesis and respiratory epithelium differentiation. At the pseudoglandular and canalicular stages of airway development, LN5 and its constituent chains were localized in the basement membrane (BM) of the proximal respiratory tubules and in the cytoplasm of the epithelial cells forming the growing epithelial buds, which expressed Int alpha2beta1, alpha3beta1, and, transiently, alpha6beta1.

Fluticasone propionate inhibits lipopolysaccharide-induced proinflammatory response in human cystic fibrosis airway grafts.

Airway inflammation, one of the major factors leading to lung damage in cystic fibrosis (CF) patients, is associated with an abnormal increase in proinflammatory cytokines. In this work, we demonstrate the increased release of the proinflammatory cytokines after lipopolysaccharide (LPS) stimulation: human interleukin (hIL)-8 in CF and non-CF airway xenografts, and hIL-6 and human growth-related oncogene-alpha (hGRO-alpha), which could be only analyzed in non-CF xenografts. Under basal conditions, we observed that hIL-8 was higher in CF xenografts compared with non-CF.

Polarized expression of cystic fibrosis transmembrane conductance regulator and associated epithelial proteins during the regeneration of human airway surface epithelium in three-dimensional culture.

We have previously shown that, in normal human airway tissue, localization of the cystic fibrosis transmembrane conductance regulator (CFTR) can be affected by epithelial maturation, polarity, and differentiation and that CFTR trafficking and apical localization depend on the integrity of the airway epithelium. In this study, we addressed the question of whether the three-dimensional (3-D) organization of adult human airway epithelial cells in suspension culture under rotation, leading to spheroid-like structures, could mimic the in vivo phenomenon of differentiation and polarization. The kinetics of the differentiation, polarity, and formation of the CFTR-ZO-1-ezrin complex was analyzed by transmission, scanning, and immunofluorescence microscopy.