Modulation of myofibroblast and smooth-muscle phenotypes in the lung.

Considerable progress has been made in defining the phenotype of contractile cells of the lung during development, in the adult and during the remodeling process. The high degree of phenotypic heterogeneity of subgroups of these cells, such as SMCs, is appreciated. Recent studies also have explored the relationship between phenotype and cell function, though this remains an important area for research in the coming years. Similarly, though our understanding of the regulation of cell phenotype is expanding rapidly, much remains to be done, particularly at the level of gene regulation. New transgenic models, coupled with gene-promotor analyses in transgenic animals and in cultured cells should allow rapid progress. Studies of the regulation of specific contractile and cytoskeletal proteins at the gene level by specific cytokines and extracellular-matrix elements will be particularly important.