Expression of neutrophil gelatinase-associated lipocalin regulates epithelial morphogenesis in vitro.
Growth factors such as hepatocyte growth factor (HGF) are highly up-regulated during development and following renal injury and are known to induce marked morphogenic actions in cultured tubular epithelial cells, including scattering, migration, single cell branching morphogenesis, and multicellular branching tubulogenesis. In the present study, we demonstrate that HGF stimulates epithelial cells to express neutrophil gelatinase-associated lipocalin (Ngal), a member of the lipocalin family of secreted proteins that has recently been shown to participate in mesenchymal-epithelial transformation via its ability to augment cellular iron uptake. At concentrations below those found to mediate iron transport, purified Ngal can induce a promigratory and probranching effect that is dependent on ERK activation. The suppression of Ngal expression using short hairpin RNA results in increased cyst formation by tubular cells. However, the simultaneous addition of Ngal and HGF leads to direct association of the two proteins, and results in a partial inhibition of HGF-mediated activation of c-Met and the downstream MAPK and phosphatidylinositol 3-kinase signaling pathways. This inhibitory effect down-regulates HGF-stimulated single cell migration, and limits branching morphogenesis at both the single cell and multicellular level. These experiments demonstrate that the local expression of Ngal can play a regulatory role in epithelial morphogenesis by promoting the organization of cells into tubular structures while simultaneously negatively modulating the branching effects of HGF.
Gwira
Jane A
JA
Department of Medicine, Yale University, New Haven, Connecticut 06520, USA.
Wei
Feng
F
Ishibe
Shuta
S
Ueland
Joseph M
JM
Barasch
Jonathan
J
Cantley
Lloyd G
LG
D000209:Acute-Phase Proteins / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D002465:Cell Movement; D017077:Culture Media, Conditioned / Q000494:pharmacology; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004815:Epidermal Growth Factor / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology; D004848:Epithelium / Q000201:enzymology / Q000502:physiology*; D004926:Escherichia coli / Q000378:metabolism; D017228:Hepatocyte Growth Factor / Q000378:metabolism; D066298:In Vitro Techniques; D007501:Iron / Q000378:metabolism; D054835:Lipocalin 1; D000071068:Lipocalin-2; D054834:Lipocalins; D051379:Mice; D008822:Mice, Transgenic; D009024:Morphogenesis; D020411:Oligonucleotide Array Sequence Analysis; D015513:Oncogene Proteins / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D012313:RNA / Q000737:chemistry; D015398:Signal Transduction; D013997:Time Factors; D015854:Up-Regulation
D000209:Acute-Phase Proteins; D002352:Carrier Proteins; D017077:Culture Media, Conditioned; D016895:Culture Media, Serum-Free; D004815:Epidermal Growth Factor; D017228:Hepatocyte Growth Factor; D007501:Iron; D054835:Lipocalin 1; D000071068:Lipocalin-2; D054834:Lipocalins; D015513:Oncogene Proteins; D019869:Phosphatidylinositol 3-Kinases; D012313:RNA; C071332:Lcn2 protein, mouse