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Proteinases release mucin from airways goblet cells
Abstract:
The mucin-release effect of proteinases on airways epithelium was assessed in vitro. Using explants of rabbit tracheal mucosa-submucosa we determined that elastase and alkaline proteinase from Pseudomonas aeruginosa, pancreatic trypsin and elastase and the microbial proteinases subtilisin, thermolysin and pronase, all stimulate mucin release from goblet cells. On the other hand Streptomyces caespitosus proteinase pancreatic chymotrypsin and collagenase fail to trigger mucin release. Bovine trachea and human nasal polyp epithelium also release mucins in response to proteinases. Mucin release activity is dependent on proteolytic activity of enzymes which have a fairly broad, but generally similar, substrate specificity. The cellular mechanism of action is not known. We propose that mucin secretion in response to proteinases represents a useful defence mechanism but also forms the basis for hypersecretory states and airways obstruction in chronic endobronchial inflammatory states.
Insights
Certain proteinases stimulate mucin release from airway goblet cells, potentially aiding defense but also contributing to airway obstruction in chronic inflammation.
Area of Science:
- Respiratory physiology
- Enzymology
- Cell biology
Background:
- Airway epithelium secretes mucins, crucial for defense and lubrication.
- Proteinases are implicated in inflammatory airway diseases.
- The specific role of proteinases in mucin secretion is not fully understood.
Purpose of the Study:
- To investigate the in vitro effect of various proteinases on mucin release from airway epithelium.
- To identify which proteinases stimulate mucin secretion and explore enzyme characteristics.
Main Methods:
- In vitro assessment using explants of rabbit tracheal mucosa-submucosa.
- Testing proteinases from Pseudomonas aeruginosa, pancreas, and microbial sources.
- Examining bovine trachea and human nasal polyp epithelium responses.
Main Results:
- Elastase, alkaline proteinase (Pseudomonas aeruginosa), pancreatic trypsin and elastase, subtilisin, thermolysin, and pronase stimulated mucin release.
- Streptomyces caespitosus proteinase, pancreatic chymotrypsin, and collagenase did not trigger mucin release.
- Mucin release activity correlated with enzyme proteolytic activity and broad substrate specificity.
Conclusions:
- Proteinases can induce mucin secretion from airway goblet cells.
- This response may serve as a defense mechanism.
- Aberrant proteinase-induced mucin secretion could underlie hypersecretory states and airway obstruction in chronic inflammatory conditions.