Differential beta(3) Integrin Expression Regulates the Response of Human Lung and Cardiac Fibroblasts to Extracellular Matrix and Its Components

摘要

Extracellular matrix (ECM) derived from whole organ decellularization has been successfully used in a variety of tissue engineering applications. ECM contains a complex mixture of functional and structural molecules that are ideally suited for the tissue from which the ECM is harvested. However, decellularization disrupts the structural properties and protein composition of the ECM, which may impact function when cells such as the fibroblast are reintroduced during recellularization. We hypothesized that the ECM structure and composition, fibroblast source, and integrin expression would influence the fibroblast phenotype. Human cardiac fibroblasts (HCFs) and normal human lung fibroblasts (NHLFs) were cultured on intact cardiac ECM, collagen gels, and coatings composed of cardiac ECM, lung ECM, and individual ECM components (collagen and fibronectin [FN]) for 48h. COL1A expression of HCFs and NHLFs cultured on ECM and FN coatings decreased to <50% of that of untreated cells; COL1A expression for HCFs cultured on ECM coatings was one- to twofold higher than HCFs cultured on intact ECM. NHLFs cultured on ECM and FN coatings expressed 12- to 31-fold more alpha-smooth muscle actin (SMA) than HCFs; the SMA expression for HCFs and NHLFs cultured on ECM coatings was approximate to 2- to 5-fold higher than HCFs and NHLFs cultured on intact ECM. HCFs expressed significantly higher levels of (3) and (4) integrins when compared to NHLFs. Inhibition of the (3) integrin, but not (4), resulted in a 16- to 26-fold increase in SMA expression in HCFs cultured on ECM coatings and FN. Our results demonstrate that (3) integrin expression depends on the source of the fibroblast and that its expression inhibits SMA expression (and thus the myofibroblast phenotype). We conclude that the fibroblast source and integrin expression play important roles in regulating the fibroblast phenotype.