title: Basic fibroblast growth factor activates ERK and induces c-fos in human embryonic stem cell line MizhES1.
abstract: Human embryonic stem (hES) cells can be maintained in a proliferative undifferentiated state in vitro by growing them on feeder layers of mouse embryonic fibroblast (MEF) cells along with basic fibroblast growth factor (bFGF/FGF-2). To understand the molecular mechanisms involved in the requirement of bFGF in human ES cells, we investigated expression of FGF receptors and intracellular signaling events in response to bFGF in human ES cell line MizhES1. On the basis of the results of RT-PCR, clear expression of FGF receptors FGFR1, FGR2, and FGFR3 was noticed. Because MAPK, PI3K, and PKC pathways are well-known pathways triggered by bFGF in other cells, these pathways were investigated after stimulation with bFGF. bFGF did not induce activation of PI3K or PKC, but induced activation of ERK (extracellular signal-regulated kinase). To monitor the consequences of ERK activation, we examined expression of the immediate early gene c-fos, one downstream target of the MEK1/ERK pathway. mRNA and protein levels of the c-fos gene were increased by bFGF. Induction of c-Fos was dependent on MEKl. Therefore, it is likely that bFGF contributes to maintenance of human ES cells, at least in part, through the MEK1/ERK pathway.
authors.affiliation: Department of Biochemistry, Biotechnology Research Institute, College of Natural Sciences, Chungbuk National University, Cheongju, Chungbuk, 361-763, Korea.
authors.forename: Ho Bum
authors.initials: HB
authors.lastname: Kang
authors.forename: Jin Sook
authors.initials: JS
authors.lastname: Kim
authors.forename: Hyung-Joo
authors.initials: HJ
authors.lastname: Kwon
authors.forename: Ki Hoan
authors.initials: KH
authors.lastname: Nam
authors.forename: Hyun Soo
authors.initials: HS
authors.lastname: Youn
authors.forename: Dai-Eun
authors.initials: DE
authors.lastname: Sok
authors.forename: Younghee
authors.initials: Y
authors.lastname: Lee
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D002478:Cells, Cultured; D003094:Collagen / Q000494:pharmacology; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000378:metabolism; D004338:Drug Combinations; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D015151:Immunoblotting; D007797:Laminin / Q000494:pharmacology; D051379:Mice; D018613:Microscopy, Confocal; D050814:Octamer Transcription Factor-3; D027701:Organic Cation Transport Proteins / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011509:Proteoglycans / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D051496:Receptor, Fibroblast Growth Factor, Type 1; D051497:Receptor, Fibroblast Growth Factor, Type 2; D051498:Receptor, Fibroblast Growth Factor, Type 3; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology*; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D000099254:Organic Cation Transporter 3
chemical_list: D003094:Collagen; D016895:Culture Media, Serum-Free; D004268:DNA-Binding Proteins; D004338:Drug Combinations; D048049:Extracellular Signal-Regulated MAP Kinases; D016222:Fibroblast Growth Factor 2; D007797:Laminin; D050814:Octamer Transcription Factor-3; D027701:Organic Cation Transport Proteins; D019869:Phosphatidylinositol 3-Kinases; D011493:Protein Kinase C; D011505:Protein-Tyrosine Kinases; D011509:Proteoglycans; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1; D051497:Receptor, Fibroblast Growth Factor, Type 2; D051498:Receptor, Fibroblast Growth Factor, Type 3; D017468:Receptors, Fibroblast Growth Factor; D014157:Transcription Factors; D000099254:Organic Cation Transporter 3; C494173:POU5F1 protein, human; C494174:Pou5f1 protein, mouse; C059485:matrigel; C496348:FGFR1 protein, human; C496353:FGFR2 protein, human; C496365:FGFR3 protein, human; C496349:Fgfr1 protein, mouse; C496354:Fgfr2 protein, mouse; C496366:Fgfr3 protein, mouse