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Effect of platelet-activating factor on secretion of mucous glycoprotein from chinchilla middle ear epithelial cells
1Department of Otolaryngology, University of innesota Otitis Media Research Center, University of Minnesota Medical School, Minneapolis 55455, USA.
Abstract:
Platelet-activating factor (PAF) is a naturally occurring phospholipid that acts as a pleiotropic mediator and mediates cell-cell reactions under physiological and pathological conditions. Recently, it has been shown that PAF is a strong secretagogue of mucous glycoprotein in the airways, suggesting its role in mucous glycoprotein secretion and the pathogenesis of otitis media with effusion. In the current study, we examined the effect of PAF on mucous glycoprotein secretion in cultured chinchilla middle ear epithelial cells. PAF at 1 microM significantly stimulated mucous glycoprotein secretion from cultured chinchilla middle ear epithelial cells. This action was concentration-dependent, with secretions reaching near maximum when the cells were incubated with PAF at 100 microM. In a time-dependent study, PAF demonstrated an initial rapid stimulation of mucous glycoprotein secretion, followed by a gradual increase thereafter. A six-fold increase was seen in the first 2 h compared with controls. Cycloheximide, a protein synthesis inhibitor, demonstrated an inhibitory effect on PAF-stimulated mucous glycoprotein secretion in this study. These findings suggest that PAF plays an important role in the pathogenesis of otitis media with effusion by stimulating mucous glycoprotein secretion in vitro.
Insights
Platelet-activating factor (PAF) significantly increases mucous glycoprotein secretion in middle ear cells. This finding suggests PAF
Area of Science:
- Otorhinolaryngology
- Immunology
- Cell Biology
Background:
- Platelet-activating factor (PAF) is a phospholipid mediator involved in physiological and pathological cell-cell reactions.
- PAF is a potent secretagogue for mucous glycoprotein in airways, implicating it in otitis media with effusion pathogenesis.
Purpose of the Study:
- To investigate the effect of Platelet-activating factor (PAF) on mucous glycoprotein secretion in cultured chinchilla middle ear epithelial cells.
Main Methods:
- Cultured chinchilla middle ear epithelial cells were treated with varying concentrations of PAF.
- Mucous glycoprotein secretion was measured over time.
- The effect of cycloheximide (protein synthesis inhibitor) on PAF-stimulated secretion was assessed.
Main Results:
- PAF significantly stimulated mucous glycoprotein secretion in a concentration-dependent manner.
- PAF induced a rapid and sustained increase in secretion, with a six-fold rise in the first 2 hours.
- Cycloheximide inhibited PAF-stimulated mucous glycoprotein secretion.
Conclusions:
- Platelet-activating factor (PAF) stimulates mucous glycoprotein secretion in middle ear epithelial cells.
- These findings support a significant role for PAF in the pathogenesis of otitis media with effusion via enhanced mucous secretion.