Bronchial epithelial cell migration, attachment, and proliferation are important processes in response to airway injury. We have shown that tumor necrosis factor (TNF)-α stimulates the migration of bovine bronchial epithelial cells (BBEC) in vitro. We hypothesized that protein kinase C (PKC) may be one of the intracellular signaling mediators of TNF-α in BBEC. In this study, we have identified multiple PKC isoforms in BBEC and measured total cellular PKC activity. Polyclonal antibodies to the PKC-α, -β2, -δ, and -ε isoforms recognized protein bands around 80–90 kDa. BBEC primary cultures treated with either 500 U/ml TNF-α for 2–4 h or 100 ng/ml 12- O-tetradecanoylphorbol 13-acetate for 15 min resulted in three- to fivefold increases in PKC activity in the particulate fractions of crude cell lysates. This activity was inhibited by 1 μM calphostin C or 10 μM H-7. Similarly, TNF-α-stimulated BBEC migration was reduced at least twofold in the presence of H-7 or calphostin C. These studies suggest that the activation of PKC is necessary for TNF-α-stimulated BBEC migration.

These results suggested that histamine may play a regulatory role in goblet cell hyperplasia in allergic airway inflammation.

No abstract

Abstract. Although histamine is a central mediator in the immediate allergic reaction, its role in goblet cell hyperplasia in the airway of asthma is not completely understood. This study was designed to examine the role of histamine in goblet cell hyperplasia using histamine-deficient mice (Hdc −/ − mice) with allergic airway inflammation. Wild-type and Hdc −/ − C57BL/ 6 mice were sensitized with ovalbumin (OVA). After two-week exposure to OVA, goblet cell hyperplasia was evaluated. Cell differentials in BALF were analyzed. The mRNAs level of MUC5AC and Gob-5 gene were quantitatively determined. The number of eosinophils in BALF increased in both the wild-type mice and Hdc −/ − mice; however, their ratio in Hdc −/ − mice was significantly lower than that in the wild-type mice. The mRNA levels of Gob-5 and MUC5AC and the ratio of the goblet cells in the airway epithelium were significantly increased in Hdc −/ − mice exposed to OVA compared to the wild-type mice under the same condition. These results suggested that histamine may play a regulatory role in goblet cell hyperplasia in allergic airway inflammation.

Repair of airway epithelium after viral infection involves migration of epithelial cells to cover injured, denuded areas. We determined whether viral infection reduces the capability of bronchial epithelial cells to migrate and to attach to extracellular matrix proteins. Inoculation of bovine bronchial epithelial cells in vitro with bovine herpesvirus-1 reduced their ability to migrate in two different assays of cell migration. When attachment assays were performed, fewer cells attached to both control wells and matrix protein-precoated wells, suggesting that general mechanisms of adherence to substrates were altered by viral infection. Focal contact points of epithelial cells with the underlying matrix were evaluated with epifluorescence microscopy and monoclonal antibodies to vinculin and alpha v, an integrin chain. Disruption of focal contact points was seen early after infection and was prevented by an inhibitor of viral DNA polymerase, phosphonoacetic acid. Cycloheximide did not cause similar disruptions of focal contacts at early time points. Viral infection thus has marked effects on the interactions of bronchial epithelial cells with extracellular matrix and the organization of matrix to cytoskeleton links. The effects appear to be dependent in part on viral replication in the cells and are not simply due to reductions in host cell protein synthesis.