Role of neuregulin-1ß in dexamethasone-enhanced surfactant synthesis in fetal type II cells.

It is well established that glucocorticoids elevate the production of fibroblast-pneumocyte factor (FPF), which induces type II cells to synthesize surfactant phospholipids. FPF, however, has not been identified and it is not clear whether it is a single factor or a complex mixture of factors. In this study it has been shown that, when lung fibroblasts are exposed to dexamethasone, the concentration of neuregulin-1ß (NRG1ß) in conditioned medium is elevated 2-fold (P<0.05), even though NRG1ß gene expression is unaffected. This, together with the finding that exposure of type II cells to NRG1ß directly stimulates by 3-fold the rate of phospholipid synthesis (P<0.05), suggests that NRG1ß is a component of FPF that promotes lung development.