title: Functional role of JNK in neuritogenesis of PC12-N1 cells.
abstract: JNKs, also known as SAPKs, are activated in response to a wide variety of factors including growth factors, cytokines, UV radiation, and heat shock. In the rat pheochromocytoma PC12 cells, the JNK signaling pathway mediates diverse functions such as differentiation and apoptosis. We have previously shown that activated JNK is required for later stages of neuritogeneis induced by NGF in a variant PC12 cell line (N1). Here, the functional role of JNK in N1 cells is further investigated. We show that NGF treatment, which induces extensive neurite branching and cell soma enlargement in the N1 cells, stimulates a biphasic activation of JNK. The first phase of activation is rapid and transient, beginning at 15 min after NGF exposure and lasting approximately 45 min. The second phase of activation is sustained, beginning at 9-12 h of NGF treatment and lasting for at least 24 h. Similar biphasic pattern of JNK activation is also observed in the parental PC12 cells. Using the specific JNK inhibitor SP600125, we show that the biphasic activation is necessary for neurite outgrowth and branching, and that inhibition of either phase suppresses neuritogenesis in the N1 cells. These results suggest that dynamic JNK activation may play a key role in neurite outgrowth during neuronal development.
authors.affiliation: Department of Pathology, University of Oklahoma Health Sciences Center, PO Box 26901, 975 NE 10th St. BRC-256, Oklahoma City, 73190, USA.
authors.forename: Jingnan
authors.initials: J
authors.lastname: Xiao
authors.forename: Anuradha
authors.initials: A
authors.lastname: Pradhan
authors.forename: Yuechueng
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002454:Cell Differentiation / Q000187:drug effects; D002531:Cerebellum / Q000166:cytology; D004789:Enzyme Activation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology; D020932:Nerve Growth Factor / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D016716:PC12 Cells; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D013997:Time Factors
chemical_list: D020932:Nerve Growth Factor; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases