Phenotypic modulations of cultured canine airway smooth muscle cells and growth-arrested cells

Abstract

Vascular SMCs are known to exhibit phenotypic switching in culture. There is a paucity of data relating to the development of the type of switching in airway smooth muscle. This was the rationale for the current study the objective of which was to determine whether airway SMCs in culture modulate from a contractile to a synthetic type. As SMCs modulate from a contractile to a proliferative state, there is enhanced expression of "non-muscle" (nm)-isoforms and a concomitant reduction in smooth muscle (sm-) isoforms of various proteins. MLCK regulates acto-myosin interactions and plays a role in modulating contraction, cell motility and cytokinesis. In this study the abundance of MLCK isoforms in freshly isolated and cultured canine tracheal SMCs was determined by Western blot analysis using isoform-specific antibodies. The second hypothesis tested was that cells in culture change into a unique phenotype with serum deprivation. To study the effect of serum deprivation on phenotypic modulation in post-confluentcultured cells, long term serum deprivation (growth arrest) was used. (Abstract shortened by UMI.)