Supplementary Material for: Exogenous Fibroblast Growth Factor-10 Induces Cystic Lung Development with Altered Target Gene Expression in the Presence of Heparin in Cultures of Embryonic Rat Lung
2012-01-18T00:00:00Z (GMT) by
<i>Objectives:</i> Signaling by fibroblast growth factor (FGF) receptor (FGFR) 2IIIb regulates branching morphogenesis in the mammalian lung. FGFR2IIIb is primarily expressed in epithelial cells, whereas its ligands, FGF-10 and keratinocyte growth factor (KGF; FGF-7), are expressed in mesenchymal cells. <i>FGF-10</i> null mice lack lungs, whereas <i>KGF</i> null animals have normal lung development, indicating that FGF-10 regulates lung branching morphogenesis. In this study, we determined the effects of FGF-10 on lung branching morphogenesis and accompanying gene expression in cultures of embryonic rat lungs. <i>Methods:</i> Embryonic day 14 rat lungs were cultured with FGF-10 (0–250 ng/ml) in the absence or presence of heparin (30 ng/ml) for 4 days. Gene expression profiles were analyzed by Affymetrix microchip array including pathway analysis. Some of these genes, functionally important in FGF-10 signaling, were further analyzed by Northern blot, real-time PCR, in situ hybridization and immunohistochemistry. <i>Results:</i> Exogenous FGF-10 inhibited branching and induced cystic lung growth only in cultures containing heparin. In total, 252 upregulated genes and 164 downregulated genes were identified, and these included <i>Spry1</i> (Sprouty-1), <i>Spry2</i> (Sprouty-2), <i>Spred-1</i>, <i>Bmp4</i> (bone morphogenetic protein-4, BMP-4), <i>Shh </i>(sonic hedgehog, SHH), <i>Pthlh</i> (parathyroid hormone-related protein, PTHrP), <i>Dusp6</i> (MAP kinase phosphatase-3, MKP-3) and <i>Clic4</i> (chloride intracellular channel-4, CLIC-4) among the upregulated genes and <i>Igf1</i> (insulin-like growth factor-1, IGF-1), <i>Tcf21</i> (POD), <i>Gyg1</i> (glycogenin 1), <i>Sparc</i> (secreted protein acidic and rich in cysteine, SPARC), <i>Pcolce</i> (procollagen C-endopeptidase enhancer protein, Pro CEP) and <i>Lox</i> (lysyl oxidase) among the downregulated genes. <i>Gsk3</i>β and <i>Wnt2,</i> which are involved in canonical Wnt signaling, were up- and downregulated, respectively. <i>Conclusions:</i> Unlike FGF-7, FGF-10 effects on lung branching morphogenesis are heparin-dependent. Sprouty-2, BMP-4, SHH, IGF-1, SPARC and POD are known to regulate branching morphogenesis; however, potential roles of CLIC-4 and MKP-3 in lung branching morphogenesis remain to be investigated. FGF-10 may also function in regulating branching morphogenesis or inducing cystic lung growth by inhibiting Wnt2/β-catenin signaling.