Heparin-binding epidermal growth factor-like growth factor stimulates cell proliferation in cerebral cortical cultures through phosphatidylinositol 3'-kinase and mitogen-activated protein kinase.
Heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) stimulates cell proliferation in the adult mammalian brain, but the mechanism involved is unknown. To address this issue we treated mouse brain cerebral cortical cultures enriched in neuronal precursors with full-length HB-EGF, its HB or EGF-like domain alone, or both domains in combination. Labeling of cultures with bromodeoxyuridine (BrdU), a marker of cell proliferation, was increased approximately 10% by the HB domain and approximately 20% by the EGF-like domain, and the effects of the two domains were additive. Full-length HB-EGF was most effective (approximately 50% increase) in stimulating BrdU incorporation. Preincubation with heparinase III or with Na-chlorate abolished cell proliferation induced by HB-EGF, consistent with dependence on cell-surface heparan sulfate proteoglycans. The effect of HB-EGF was also blocked by the EGF receptor (EGFR/ErbB1) inhibitors PD153035 and PD158780, implicating EGFR in HB-EGF-induced cell proliferation. The phosphatidylinositol 3'-kinase (PI3K) inhibitors LY294002 and wortmannin, and the MAPK/extracellular signal-regulated kinase (ERK) kinase (MEK) inhibitors U0126 and PD98059, reduced HB-EGF-induced BrdU incorporation into cultures, and HB-EGF enhanced phosphorylation of Akt and ERK, implying a role for PI3K/Akt and MEK/ERK signaling in HB-EGF-stimulated cell proliferation. These findings help to clarify the molecular mechanisms through which HB-EGF operates.
Jin
Kunlin
K
Buck Institute for Age Research, Novato, California.
Mao
Xiao Ou
XO
Del Rio Guerra
Gabriel
G
Jin
Lan
L
Greenberg
David A
DA
D000595:Amino Acid Sequence; D000818:Animals; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D019070:Cell Lineage / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology* / Q000196:embryology; D004815:Epidermal Growth Factor / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D066246:ErbB Receptors / Q000502:physiology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology
D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D048049:Extracellular Signal-Regulated MAP Kinases; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; C587884:Hbegf protein, mouse