Human surface respiratory epithelial (HSRE) cells from nasal polyps have been cultured within collagen lattices in a serum-free defined medium. Cell growth observed over a period of 12 days showed a population doubling time of 36 h. Under these culture conditions, we observed a contraction of the lattices. Phase-contrast light microscopy and transmission electron microscopy demonstrated that the HSRE cells formed tubular ductlike structures. Lumens formed by HSRE cells were surrounded by cuboidal-shaped polarized cells with numerous ciliated cells, secretory cells, and undifferentiated cells. Epidermal growth factor (EGF) was observed to stimulate the tubule formation and the contraction of the lattices. Videomicroscopic observations and analysis of the ciliary beating frequency (CBF) demonstrated that the cilia were homogeneously distributed on the whole apical surface of the ciliated cells and that their movement was well coordinated, with a CBF similar to that observed in outgrowth cells from cultured human nasal and tracheal epithelia. Immunofluorescent staining of basement membrane components synthesized and secreted by cells revealed the presence of type III collagen around the tubules. Type IV collagen and laminin were present in the cytoplasm and at the periphery of the cells. The biotin-streptavidin-gold immunocytochemical technique with monoclonal anti-mucin antibody showed intracellular localization of mucins in secretory granules of the secretory cells. With the use of substrate gel electrophoresis polyacrylamide gels impregnated with gelatin, collagenase activity was detected in the conditioned medium of the cultured HSRE cells. These results suggest that both three-dimensional collagen gel and soluble factors such as EGF regulate tubule formation by HSRE cells. Moreover, the capacity of the epithelial cells to contract the gel suggests they may be involved in the wound healing process.
We have investigated the effect of both adenosine triphosphate (ATP) and uridine triphosphate (UTP) on the fluid transport, transepithelial electric potential difference (PD), and unidirectional chloride flux when applied apically to cultured human surface respiratory epithelial (HSRE) cells in a double-compartment chamber. The effects of ATP and UTP (both 100 microM) were examined in cells either untreated or pretreated with 100 microM amiloride in lactated Ringer's solution. ATP or UTP was added to the apical solution in a 100 microliters final volume. After a 2-h incubation period, the change in fluid transport was measured by weighing the apical fluid. Compared with control, amiloride blocked the fluid absorption by HSRE cells. The addition of ATP or UTP, either alone or after pretreatment with amiloride, induced a similar and significant increase in the apical fluid and chloride flux (P < 0.001 and P < 0.005, respectively). The changes in both fluid transport and chloride flux were accompanied by changes in PD. A blocker for chloride transport, 4,4'-diisothiocyano-2,2'-stilbene disulfonate, at 500 microM significantly blocked the ATP-stimulated fluid transport (P < 0.05) and chloride flux (P < 0.01). These results support the hypothesis that extracellular ATP and UTP increase the fluid transport by respiratory epithelial cells and may be useful in the hydration of mucus and respiratory mucosa.
Inflammation and epithelial damage of the bronchial mucosa are frequently identified in children with bronchial diseases. Nevertheless, until now the quantitative assessment of the epithelial damage has never been studied in relation to clinical or respiratory function or mucus abnormalities. Bronchial biopsies and brushings were performed in 31 children with recurrent bronchitis and without atopia. The quantitative histologic data were compared with clinical results, the endoscopic appearance of the mucosa, ciliary beating frequency, mucus transport capacity, leukocyte count, and protein concentration in mucus samples. Most of the biopsies (87%) collected in this group of children without recent acute infections showed extensive epithelial damage. A significant correlation was observed between the degree of shedding and edema (p < 0.01). Bronchial epithelial edema was associated with a significantly decreased (p < 0.01) mucus transport rate. Inflammation of the submucosa was significantly correlated with lymphocyte epithelial infiltration (p < 0.01), total mucus protein content (p < 0.01), and local airway inflammation estimated by bronchoscopy. These results demonstrate that children with recurrent bronchitis develop a severe bronchial inflammation associated with an increased mucus protein content and a reduction in the mucociliary function.
We describe a method for establishing the culture of bovine tracheal submucosal gland (BTG) cells, in which we have also examined the influence of a reconstituted basement membrane matrix derived from the Engelbreth-Holm-Swarm tumor (EHS) on the growth and morphological differentiation of these cells. BTG cells have been isolated by tissue enzymatic digestion using trypsin, deoxyribonuclease I, elastase, hyaluronidase and EGTA for 1 hr at 37 degrees C. Afterwards, cells and tissue were collected by centrifugation and were incubated for 15 min with 15% newborn calf serum to inactivate the proteolytic enzymes. Enzymatic digestion using only trypsin, centrifugation and inactivation steps were repeated three times. Using this protocol, we obtained 15 +/- 4 (X 10(6] cells per g of tracheal submucosa with 72 +/- 2% (n = 5) cell viability. On microscopic observation, isolated cells were mainly composed of serous type glandular cells. Cells were cultured in a 1:1 medium of Dulbecco's Modified Eagle's/Ham's F12 supplemented with 10% fetal calf serum and subcultured in either plastic flasks or flasks coated with EHS matrix. On the plastic, the BTG cells exhibited at confluency an epithelioid appearance. They stained positively with the immunofluorescent anticytokeratin antibody and contained PAS-staining granules. By electron microscopy, lactoferrin, a protein marker specific to the serous cells, was demonstrated immunocytochemically in small secretory vesicles. BTG cells cultured on EHS matrix revealed a significantly increased growth in comparison to those cultured on plastic. In post-confluent culture of BTG cells on EHS matrix, we observed numerous dome-like structures formed by differentiated cells which were joined together around luminal spaces.
Bovine tracheal submucosal gland serous cells were cultured in medium supplemented with either 10% fetal calf serum or 2% Ultroser G, a commercial serum substitute for cell culture. The proteins synthesized and secreted into the culture medium during PsS]methionine pulse, chase and isoproterenol-stimulated periods were analyzed. Marked differences in the patterns of secretory radiolabeled proteins with M, values ranging from 15080 to 95000 were observed between pulse and chase media of cells cultured in fetal calf serum and Ultroser G. In the presence of Ultroser G, albumin-like protein production was inhibited 9596 as compared to cultures incubated with fetal calf serum. A bovine lysoxyme-type enzymatic activity was detected only in medium from stimulated cells cultured in Ultroser G. The results suggest that bovine tracheal serous cells synthesize different proteins according to the composition of culture medium and release certain proteins when adrenergically stimulated.
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