The effect of ingredients commonly used in nasal and inhaled solutions on the secretion of mucus in vitro.

Hypersecretion of mucus is associated with impaired mucociliary clearance that can influence the retention of active pharmaceutical ingredients in the airway but is also linked with recurrent airway disease. Therefore, the effect on mucin secretion of a range of ingredients used in solutions delivered to the nose and lung was studied. Mucin secretion from explants of ovine epithelium was quantified using an enzyme-linked lectin assay (ELLA) or sandwich ELLA depending on the compatibility of the ingredients with the assay.

A comparison of three mucus-secreting airway cell lines (Calu-3, SPOC1 and UNCN3T) for use as biopharmaceutical models of the nose and lung.

The aim of this work was to compare three existing mucus-secreting airway cell lines for use as models of the airways to study drug transport in the presence of mucus. Each cell line secreted mature, glycosylated mucins, evidenced by the enzyme-linked lectin assay. The secretagogue, adenylyl-imidodiphosphate, increased mucin secretion in SPOC1 (3.

Baseline Goblet Cell Mucin Secretion in the Airways Exceeds Stimulated Secretion over Extended Time Periods, and Is Sensitive to Shear Stress and Intracellular Mucin Stores.

Airway mucin secretion studies have focused on goblet cell responses to exogenous agonists almost to the exclusion of baseline mucin secretion (BLMS). In human bronchial epithelial cell cultures (HBECCs), maximal agonist-stimulated secretion exceeds baseline by ~3-fold as measured over hour-long periods, but mucin stores are discharged completely and require 24 h for full restoration. Hence, over 24 h, total baseline exceeds agonist-induced secretion by several-fold.

Endothelin increases the ciliary beat frequency of ovine airway epithelium via its interaction with endothelin a receptors.

Ovine airway epithelial explants, cultured at an air-liquid interface, were used to determine whether endothelin (ET-1) acts via ET(A)- or ET(B)-receptors to increase ciliary beat frequency (CBF). Further, the role of prostanoids and nitric oxide (NO) downstream of receptor activation was explored. CBF was measured using an image analysis system with a sampling rate of 224 frames s(-1).

A2B adenosine receptors regulate the mucus clearance component of the lung's innate defense system.

Adenosine (ADO) signaling is altered in both asthma and chronic obstructive pulmonary disease, and the A(2B) adenosine receptor (A(2B)-R) may drive pulmonary inflammation. Accordingly, it has been proposed that specific inhibition of the A(2B)-R could treat inflammatory lung diseases. However, stimulation of the cystic fibrosis transmembrane conductance regulator (CFTR) by ADO may be crucial in permitting the superficial epithelium to maintain airway surface liquid (ASL) volume, which is required to ensure hydrated and clearable mucus.

Novel quartz crystal microbalance based biosensor for detection of oral epithelial cell-microparticle interaction in real-time.

Recent applications of quartz crystal resonant sensor technology to monitor cell adhesion and specific ligand interaction processes has triggered the development of a new category of quartz crystal microbalance (QCM) based biosensors. In this study human oral epithelial cells (H376) were cultured on quartz sensors and their response to microspheres investigated in situ using the QCM technique. The results demonstrated that this novel biosensor was able to follow cell-microsphere interactions in real-time and under conditions of flow as would occur in the oral cavity.

Endothelin-1 inhibits mucin secretion from ovine airway epithelial goblet cells.

Mucus hypersecretion is a feature of several respiratory diseases and frequently leads to obstruction of small airways where the principal source of mucous glycoproteins (mucins), the major macromolecular constituents of mucus, are goblet cells. Hence, inhibition of mucin secretion from these cells may be clinically beneficial. In this study, we have developed a lectin-based assay for mucin secretion from ovine airway goblet cells and used this assay to investigate the regulation of these cells by endothelin (ET)-1.

Expression of nucleotide-regulated Cl(-) currents in CF and normal mouse tracheal epithelial cell lines.

The dominant route for Cl(-) secretion in mouse tracheal epithelium is via Cl(-) channels different from the cystic fibrosis (CF) transmembrane conductance regulator (CFTR), the channel that is defective in CF. It has been proposed that the use of purinergic agonists to activate these alternative channels in human airways may be beneficial in CF. In the present study, two conditionally immortal epithelial cell lines were established from the tracheae of mice possessing the tsA58 T antigen gene, one of which [MTE18-(-/-)] was homozygous for a knockout of CFTR and the other [MTE7b-(+/-)] heterozygous for CFTR expression.

Permeabilization via the P2X7 purinoreceptor reveals the presence of a Ca2+-activated Cl- conductance in the apical membrane of murine tracheal epithelial cells.

Calcium-activated Cl(-) secretion is an important modulator of regulated ion transport in murine airway epithelium and is mediated by an unidentified Ca(2+)-stimulated Cl(-) channel. We have transfected immortalized murine tracheal epithelial cells with the cDNA encoding the permeabilizing P2X(7) purinoreceptor (P2X(7)-R) to selectively permeabilize the basolateral membrane and thereby isolate the apical membrane Ca(2+)-activated Cl(-) current. In P2X(7)-R-permeabilized cells, we have demonstrated that UTP stimulates a Cl(-) current across the apical membrane of CF and normal murine tracheal epithelial cells.

Nucleotide regulation of goblet cells in human airway epithelial explants: normal exocytosis in cystic fibrosis.

The regulation of mucin secretion by airway goblet cells is poorly understood and the receptor-based regulatory mechanisms have not been described in human airways. In the present study, we report that extracellular triphosphate nucleotides regulate the rate of granule release from goblet cells in both normal and cystic fibrosis (CF) airway epithelial explants. Explants isolated from nasal and tracheobronchial tissues were mounted in perfusion chambers and the secretory activity was assessed by videomicroscopic determination of degranulation in single goblet cells and by ELISA determination of mucins secreted into the mucosal perfusate.

Impaired stimulus-evoked mucus secretion in cystic fibrosis bronchi.

Baseline and agonist-stimulated secretion of fucose, hexose, and protein (markers of mucus secretion) was investigated in vitro in 45 bronchial segments from 14 patients with cystic fibrosis (CF) (three after heart-lung transplant, the remainder < 4.5 h after autopsy), in 51 segments from 26 patients with carcinoma (24 resection, 2 after autopsy), and in 4 segments from 3 patients with bronchiectasis (resection). Basal rates of secretion of each mucus marker by CF bronchi were not significantly different from those by carcinoma bronchi bronchiectatic bronchi.

Goblet cell degranulation in isolated canine tracheal epithelium: response to exogenous ATP, ADP, and adenosine.

Mucin secretion by goblet cells was determined by quantifying degranulation events (DE) in isolated, superficial epithelium from canine trachea. The epithelium was isolated and explanted to a novel transparent, permeable support, and the goblet cells were visualized by video microscopy. Baseline degranulation events were quantified at 0.

The role of mucous glycoproteins in the rheologic properties of cystic fibrosis sputum.

Cystic fibrosis (CF) is characterized by excessive amounts of thick and tenacious mucous secretions that obstruct organ ducts and passages. In the respiratory tract this is associated with chronic infection resulting in the hypersecretion of purulent sputum, which the patient finds difficult to clear. We have studied the rheologic properties of purulent sputum from six patients with CF and five patients with chronic bronchitis to assess whether CF is associated with increased sputum viscoelasticity.

The origin of DNA associated with mucus glycoproteins in cystic fibrosis sputum.

The relative importance of host and bacteria-derived deoxyribonucleic acid (DNA) in the increased viscoelasticity of purulent sputum in cystic fibrosis (CF) and other airway diseases is unclear. We report the identification of the DNA associated with mucus glycoproteins purified from the purulent sputum of 9 patients with CF. Mucus glycoproteins were purified from CF sputum by gel exclusion chromatography and the co-purifying DNA isolated by phenol extraction.