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Surfactant apoprotein A secretion by human tracheobronchial epithelial cells
1First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
Respiration Physiology
|June 1, 1993
Summary
Human airway epithelial cells produce surfactant apoprotein-A (SP-A). This study confirms local SP-A production in the tracheobronchial epithelium, with secretion influenced by cell number and certain stimuli.
Area of Science:
- Pulmonary Medicine
- Cell Biology
- Biochemistry
Background:
- Surfactant apoproteins are crucial for lung function.
- The local production of surfactant apoprotein-A (SP-A) within airway walls has been debated.
Purpose of the Study:
- To investigate whether human airway walls produce SP-A.
- To characterize the regulation of SP-A secretion by airway epithelial cells.
Main Methods:
- Simultaneous immunoassay with monoclonal antibodies to measure SP-A in cultured human airway explants and epithelial cells.
- Assessment of SP-A secretion under different culture conditions and in response to methacholine (MCh) and isoproterenol (ISP).
- Immunohistochemistry and Western blot analysis to confirm SP-A presence and properties in epithelial cells.
Main Results:
- Significant SP-A concentrations were detected in cultured airway explants and epithelial cells.
- SP-A secretion was dependent on cell number, increasing with confluency.
- MCh and ISP treatments altered SP-A secretion ratios, and MCh-stimulated explant supernatant reduced SP-A secretion from epithelial cells.
- Immunohistochemistry and Western blots confirmed SP-A in epithelial cells.
Conclusions:
- The tracheobronchial epithelium is capable of synthesizing and secreting SP-A.
- SP-A production is regulated by factors such as cell density and potentially by neural or inflammatory stimuli.
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