title: What is the identity of fibroblast-pneumocyte factor?
abstract: Glucocorticoid induction of pulmonary surfactant involves a mesenchyme-derived protein first characterized in 1978 by Smith and termed fibroblast-pneumocyte factor (FPF). Despite a number of agents having been postulated as being FPF, its identity has remained obscure. In the past decade, three strong candidates for FPF have arisen. This review examines the evidence that keratinocyte growth factor (KGF), leptin or neuregulin-1β (NRG-1β) act as FPF or components of it. As with FPF production, glucocorticoids enhance the concentration of each of these agents in fibroblast-conditioned media. Moreover, each stimulates the synthesis of surfactant-associated phospholipids and proteins in type II pneumocytes. Further, some have unique activities, for example, KGF also minimizes lung injury through enhanced epithelial cell proliferation and NRG-1β enhances surfactant phospholipid secretion and β-adrenergic receptor activity in type II cells. However, even though these agents have attributes in common with FPF, it is inappropriate to specify any one of these agents as FPF. Rather, it appears that each contributes to separate mesenchymal-epithelial signaling mechanisms involved in different aspects of lung development. Given that the production of pulmonary surfactant is essential for postnatal survival, it is reasonable to suggest that several mechanisms independently regulate surfactant synthesis.
authors: School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia.
authors: George
authors: G
authors: King
authors: Tufts Medical School, Boston, Massachusetts.
authors: Megan E
authors: ME
authors: Smith
authors: School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia.
authors: Max H
authors: MH
authors: Cake
authors: Department of Pediatrics and Graduate Program in Cell, Molecular and Developmental Biology, Tufts Medical School, Boston, Massachusetts.
authors: Heber C
authors: HC
authors: Nielsen
mesh_terms: D056809:Alveolar Epithelial Cells / Q000166:cytology / Q000378:metabolism; D000818:Animals; D049109:Cell Proliferation / Q000502:physiology; D051523:Fibroblast Growth Factor 7 / Q000378:metabolism; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D005938:Glucocorticoids / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D020738:Leptin / Q000378:metabolism; D008168:Lung / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D020890:Neuregulin-1 / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D011663:Pulmonary Surfactants / Q000378:metabolism; D051497:Receptor, Fibroblast Growth Factor, Type 2 / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D005938:Glucocorticoids; D020738:Leptin; D020890:Neuregulin-1; D010743:Phospholipids; D011663:Pulmonary Surfactants; C044220:fibroblast pneumonocyte factor; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors; D051497:Receptor, Fibroblast Growth Factor, Type 2; C065104:keratinocyte growth factor receptor