Distribution of phenotypically disparate myocyte subpopulations in airway smooth muscle
Loading...
Date
2005-01-31
Authors
Halayko, AJ
Stelmack, GL
Yamasaki, A
McNeill, K
Unruh, H
Rector, E
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Phenotype and functional heterogeneity of airway smooth muscle (ASM) cells in vitro is well known, but there is limited understanding of these features in vivo. We tested whether ASM is composed of myocyte subsets differing in contractile phenotype marker expression. We used flow cytometry to compare smooth muscle myosin heavy chain (smMHC) and smooth muscle-alpha-actin (sm-alpha-actin) abundance in myocytes dispersed from canine trachealis. Based on immunofluorescent intensity and light scatter characteristics (forward and 90 degrees side scatter), 2 subgroups were identified and isolated. Immunoblotting confirmed smMHC and sm-alpha-actin were 10- and 5-fold greater, respectively, in large, elongate myocytes that comprised -60% of total cells. Immunohistochemistry revealed similar phenotype heterogeneity in human bronchial smooth muscle. Canine tracheal myocyte subpopulations isolated by flow cytometry were used to seed primary subcultures. Proliferation of subcultures established with myocytes exhibiting low levels of smMHC and sm-alpha-actin was 2 x faster than subcultures established with ASM cells with a high marker protein content. These studies demonstrate broad phenotypic heterogeneity of myocytes in normal ASM tissue that is maintained in cell culture, as demonstrated by divergent proliferative capacity. The distinct roles of these subgroups could be a key determinant of normal and pathological lung development and biology.
Description
Keywords
flow cytometry, phenotype, heterogeneity, asthma, differentiation, EXTRACELLULAR-MATRIX PROTEINS, BRONCHIAL FIBROBLASTS, CELL-PROLIFERATION, ASTHMATIC SUBJECTS, MOLECULAR-MECHANISMS, FLOW-CYTOMETRY, HETEROGENEITY, PATHOGENESIS, INFLAMMATION, HYPERPLASIA
Citation
0008-4212; CAN J PHYSIOL PHARMACOL, JAN 2005, vol. 83, no. 1, p.104 to 116.