Pseudomonas aeruginosa-induced apoptosis in airway epithelial cells is mediated by gap junctional communication in a JNK-dependent manner.

Chronic infection and inflammation of the airways is a hallmark of cystic fibrosis (CF), a disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. The response of the CF airway epithelium to the opportunistic pathogen Pseudomonas aeruginosa is characterized by altered inflammation and apoptosis. In this study, we examined innate immune recognition and epithelial responses at the level of the gap junction protein connexin43 (Cx43) in polarized human airway epithelial cells upon infection by PAO1.

Approaches to study differentiation and repair of human airway epithelial cells.

One of the main functions of the airway mucosa is to maintain a mechanical barrier at the air-surface interface and to protect the respiratory tract from external injuries. Differentiation of human airway epithelial cells (hAECs) to polarized airway mucosa can be reproduced in vitro by culturing the cells on microporous membrane at the air-liquid interface. Here, we describe approaches to study differentiation as well as repair of the hAECs by using a commercially available airway cell culture model called MucilAir™.

Prostaglandin E₂regulation of cystic fibrosis transmembrane conductance regulator activity and airway surface liquid volume requires gap junctional communication.

Stimulation of the cystic fibrosis transmembrane conductance regulator (CFTR) by protease-activated receptors (PARs) at the basolateral membranes and by adenosine receptors (ADO-Rs) at the apical membrane maintain airway surface liquid (ASL) volume, which is required to ensure hydrated and clearable mucus. Both pathways involve the release of prostaglandin E₂ (PGE₂) and the stimulation of their basolateral receptors (EP-Rs). We sought to determine whether gap junctions contribute to the coordination of these pathways for modulating CFTR activity and mucus hydration.

CFTR in a lipid raft-TNFR1 complex modulates gap junctional intercellular communication and IL-8 secretion.

Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) cause a chronic inflammatory response in the lung of patients with Cystic Fibrosis (CF). We have showed that TNF-alpha signaling through the Src family tyrosine kinases (SFKs) was defective as determined by an inability of TNF-alpha to regulate gap junctional communication (GJIC) in CF cells. Here, we sought to elucidate the mechanisms linking TNF-alpha signaling to the functions of CFTR at the molecular level.

Functional expression of connexin30 and connexin31 in the polarized human airway epithelium.

Gap junctions are documented in the human airway epithelium but the functional expression and molecular identity of their protein constituents (connexins, Cx) in the polarized epithelium is not known. To address this question, we documented the expression of a family of epithelial Cx (Cx26, Cx30, Cx30.3, Cx31, Cx31.

Gap junctional communication does not contribute to the interaction between neutrophils and airway epithelial cells.

Cystic fibrosis (CF) is characterized by intense neutrophil migration into the airways. Increasing evidence indicates that interaction between neutrophils and airway epithelial cells contributes to the modulation of the inflammatory response. Blood neutrophils were reported to express connexins and form gap junctions with endothelial cells, thereby establishing gap junctional communication.

Long-term cultures of polarized airway epithelial cells from patients with cystic fibrosis.

The poor ability of respiratory epithelial cells to proliferate and differentiate in vitro into a pseudostratified mucociliated epithelium limits the general use of primary airway epithelial cell (AEC) cultures generated from patients with rare diseases, such as cystic fibrosis (CF). Here, we describe a procedure to amplify AEC isolated from nasal polyps and generate long-term cultures of the respiratory epithelium. AEC were seeded onto microporous permeable supports that carried on their undersurface a preformed feeder layer of primary human airway fibroblasts.

Gap junctional communication in tissue inflammation and repair.

Local injury induces a complex orchestrated response to stimulate healing of injured tissues, cellular regeneration and phagocytosis. Practically, inflammation is defined as a defense process whereby fluid and white blood cells accumulate at a site of injury. The balance of cytokines, chemokines, and growth factors is likely to play a key role in regulating important cell functions such as migration, proliferation, and matrix synthesis during the process of inflammation.

Defective activation of c-Src in cystic fibrosis airway epithelial cells results in loss of tumor necrosis factor-alpha-induced gap junction regulation.

Tumor necrosis factor-alpha (TNF-alpha) signaling is central to the transmission of the innate immune response and subsequent activation of the adaptive immune system. The functioning of both systems is required for optimal clearance of pathogens from the airways. In cystic fibrosis (CF), dysfunction of the CF transmembrane conductance regulator (CFTR) is associated with recurrent pulmonary infections despite an intense inflammatory and immune response.

Characterization of a novel chemotactic factor for neutrophils in the bronchial secretions of patients with cystic fibrosis.

Chronic airway inflammation is a hallmark of cystic fibrosis (CF). Biological products with chemotactic activity are essential for neutrophil recruitment to sites of inflammation. The presence of a factor with chemotactic activity higher than that of interleukin (IL)-8 in the bronchial secretions of patients with CF has recently been reported.