Growth and differentiation of primary tracheal epithelial cells in culture: regulation by extracellular calcium.
Growth and differentiation of primary monkey tracheal epithelial (MTE) cells maintained on collagen gel substrata were studied in a defined serum-free culture medium containing 0.03 to 3.0 mM extracellular calcium. Cell attachment efficiency (40-60%) was not altered by different calcium levels. Growth of primary MTE cells on collagen gel substrata, which was vitamin A dependent, was enhanced 50% in the medium supplemented with high calcium (greater than 0.3 mM). High calcium medium also increased cell-cell interactions, formation of desmosomes, and multi-cell layering. The relative content of mucous cells, which were identified by a mucin-specific monoclonal antibody and the presence of mucus-secreting granules at the ultrastructural level, was greater in the high-calcium medium. Furthermore, the secretion of mucin into the medium, determined either by an ELISA or by the incorporation of 3H-glucosamine into mucous glycoprotein fractions, was also increased more than 5-fold in media containing high calcium content (greater than 0.6 mM). In contrast, MTE cells cultured in low calcium medium (less than 0.15 mM) were squamous-like with prominent tonofilaments, and their secretory product was mainly hyaluronate. These results demonstrate that media containing a high calcium content promote conducting airway epithelium to express mucous cell differentiation, while media with low calcium content promote squamous cell differentiation.
Martin
W R
WR
Department of Internal Medicine, School of Medicine, University of California, Davis 95616.
Brown
C
C
Zhang
Y J
YJ
Wu
R
R
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells; D006001:Glycoconjugates / Q000378:metabolism; D066298:In Vitro Techniques; D008253:Macaca mulatta; D008854:Microscopy, Electron; D009077:Mucins / Q000378:metabolism*; D014132:Trachea / Q000166:cytology*; D014801:Vitamin A / Q000494:pharmacology
D006001:Glycoconjugates; D009077:Mucins; D014801:Vitamin A; D002118:Calcium