title: Phospholipase D1 mediates bFGF-induced Bcl-2 expression leading to neurite outgrowth in H19-7 cells.
abstract: The purpose of the present study was to investigate the role of PLD (phospholipase D) in bFGF (basic fibroblast growth factor)-induced Bcl-2 expression and to examine whether overexpressed Bcl-2 influences neurite outgrowth in immortalized hippocampal progenitor cells (H19-7 cells). We found that Bcl-2 expression was maximally induced by bFGF within 24 h, and that this effect was reduced by inhibiting PLD1 expression with PLD1 small interfering RNA or by overexpressing DN (dominant-negative)-PLD1, whereas PLD1 overexpression markedly induced Bcl-2 expression. bFGF treatment activated Ras, Src, PI3K (phosphoinositide 3-kinase), PLCγ (phospholipase Cγ) and PKCα (protein kinase Cα). Among these molecules, Src and PKCα were not required for Bcl-2 expression. PLD activity was decreased by Ras, PI3K or PLCγ inhibitor, suggesting that PLD1 activation occurred through Ras, PI3K or PLCγ. We found that Ras was the most upstream molecule among these proteins, followed by the PI3K/PLCγ pathway, indicating that bFGF-induced PLD activation took place through the Ras/PI3K/PLCγ pathway. Furthermore, PLD1 was required for activation of JNK (c-Jun N-terminal kinase), which led to activation of STAT3 (signal transducer and activator of transcription 3) and finally Bcl-2 expression. When Bcl-2 was overexpressed, neurite outgrowth was stimulated along with induction of neurotrophic factors such as brain-derived neurotrophic factor and neurotrophin 4/5. In conclusion, PLD1 acts as a downstream effector of bFGF/Ras/PI3K/PLCγ signalling and regulates Bcl-2 expression through JNK/STAT3, which leads to neurite outgrowth in H19-7 cells.
authors.affiliation: Department of Surgery, College of Medicine, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Sung Nyo
authors.initials: SN
authors.lastname: Yoon
authors.forename: Kang Sik
authors.initials: KS
authors.lastname: Kim
authors.forename: Ju Hwan
authors.initials: JH
authors.lastname: Cho
authors.forename: Weina
authors.initials: W
authors.lastname: Ma
authors.forename: Hye-Jin
authors.initials: HJ
authors.lastname: Choi
authors.forename: Sung-Joon
authors.initials: SJ
authors.lastname: Kwon
authors.forename: Joong-Soo
authors.initials: JS
authors.lastname: Han
mesh_terms: D000818:Animals; D002460:Cell Line; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D048670:MAP Kinase Kinase 4 / Q000235:genetics / Q000378:metabolism; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism; D016501:Neurites / Q000502:physiology*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D051966:Phospholipase C gamma / Q000235:genetics / Q000378:metabolism; D010739:Phospholipase D / Q000235:genetics / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D009414:Nerve Growth Factors; D019253:Proto-Oncogene Proteins c-bcl-2; D050796:STAT3 Transcription Factor; C494088:Stat3 protein, rat; D005346:Fibroblast Growth Factors; D019869:Phosphatidylinositol 3-Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D048670:MAP Kinase Kinase 4; D051966:Phospholipase C gamma; D010739:Phospholipase D; C106801:phospholipase D1; D018631:ras Proteins