Abstract
Contraction of type I collagen gels is an in vitro model of tissue remodeling. In addition to fibroblasts, some epithelial cells can mediate this process. We therefore hypothesized that alveolar epithelial cells might contract extracellular matrices and have the potential to directly participate in the remodeling of the lung after alveolar injury. A549 cells were plated on top of collagen gels, and the gels were floated in culture medium. A549 cells contracted the gels in a time- and cell density–dependent manner. A549 cells, as well as human bronchial epithelial cells (HBEC) and rat alveolar epithelial cells (RalvEC) contracted collagen gels more when they were plated on top of the gel than when they were embedded inside, in contrast to human fetal lung fibroblast (HFL1), which contracted more when cast inside. The amount of hydroxyproline in the collagen gels remained unchanged throughout the contraction. Anti– β1 integrin antibody inhibited A549 cell–mediated contraction. Transforming growth factor β a...
