transforming-growth-factor-alpha and Hypersensitivity

To investigate the effect of Asian sand dust (ASD) on mucin production in human respiratory epithelial cells in vitro and in allergic murine nasal epithelial cells.. Controlled, in vitro.. Academic research laboratory.. Human NCI-H292 cells were treated with ASD and analyzed by immunostaining, reverse transcriptase-polymerase chain reaction for MUC5AC mRNA expression, and Periodic Acid Schiff (PAS) staining. Forty female BALB/c mice were classified into 4 groups. Two groups were sensitized with ovalbumin (OVA), and 1 of these was treated with ASD (ASD+OVA). The 2 nonsensitized groups were treated with ASD or saline. Then the murine nasal mucosal tissues were evaluated by hematoxylin and eosin (H&E) staining, PAS staining, and immunostaining for MUC5AC and transforming growth factor (TGF)-α proteins.. The numbers of MUC5AC-immunopositive NCI-H292 cells and PAS-positive NCI-H292 cells were significantly higher in the ASD-treated cells than in the control cells (P = .039 and P = .029, respectively). MUC5AC mRNA expression in the cells increased with increasing concentrations of ASD. In the murine nasal epithelial tissues, the numbers of eosinophils and PAS-positive cells were significantly higher in the ASD+OVA group than in the OVA group (H&E staining, P = .037; PAS staining, P = .019). At 2 weeks, the numbers of MUC5AC- and TGF-α-positive cells in the nasal epithelial tissue were significantly higher in the ASD+OVA group than in the OVA group (P = .031 and P = .033, respectively).. ASD can induce mucin production in respiratory epithelial cells.

Topics: Animals; Cell Culture Techniques; Disease Models, Animal; Dust; Epithelial Cells; Female; Humans; Hypersensitivity; Mice; Mice, Inbred BALB C; Mucin 5AC; Ovalbumin; Respiratory Mucosa; Silicon Dioxide; Transforming Growth Factor alpha

Eosinophil recruitment and mucus hypersecretion are characteristic of asthmatic airway inflammation, but eosinophils have not been shown to induce mucin production. Because an epidermal growth factor receptor (EGFR) cascade induces MUC5AC mucin in airways, and because EGFR is up-regulated in asthmatic airways, we examined the effect of eosinophils on MUC5AC mucin production in NCI-H292 cells (a human airway epithelial cell line that produces mucins). Eosinophils were isolated from the peripheral blood of allergic patients, and their effects on MUC5AC mucin gene and protein synthesis were assessed using in situ hybridization and ELISAs. When IL-3 plus GM-CSF or IL-3 plus IL-5 were added to eosinophils cultured with NCI-H292 cells, MUC5AC mucin production increased; eosinophils or cytokines alone had no effect. Eosinophil supernatant obtained by culturing eosinophils with IL-3 plus GM-CSF or IL-3 plus IL-5 also increased MUC5AC synthesis in NCI-H292 cells, an effect that was prevented by selective EGFR inhibitors (AG1478, BIBX1522). Supernatant of activated eosinophils induced EGFR phosphorylation in NCI-H292 cells. Supernatant of activated eosinophils contained increased concentrations of TGF-alpha protein (an EGFR ligand) and induced up-regulation of TGF-alpha expression and release in NCI-H292 cells. A blocking Ab to TGF-alpha reduced activated eosinophil-induced MUC5AC synthesis in NCI-H292 cells. These results show that activated eosinophils induce mucin synthesis in human airway epithelial cells via EGFR activation, and they implicate TGF-alpha produced by eosinophils and epithelial cells in the EGFR activation that results in mucin production in human airway epithelium.

Topics: Adult; Asthma; Cells, Cultured; Culture Media, Conditioned; Enzyme Inhibitors; Eosinophils; ErbB Receptors; Humans; Hypersensitivity; Middle Aged; Mucin 5AC; Mucins; Phosphorylation; Pulmonary Eosinophilia; Quinazolines; Respiratory Mucosa; RNA, Messenger; Transforming Growth Factor alpha; Tumor Cells, Cultured; Tyrphostins; Up-Regulation