Increase in neurite formation and acetylcholine release by transfection of growth-associated protein-43 cDNA into NG108-15 cells.
We previously reported that growth-associated protein-43 (GAP-43) could be involved in the maintenance of elongated neurites and that a decline in protein kinase C activity may be involved in accumulation of GAP-43. In the present study, to clarify the functional significance of GAP-43 for neurite maintenance and acetylcholine (ACh) release, we prepared NG-G11 cells by transfection of GAP-43 cDNA into NG108-15 cells. NG-G11 cells expressed GAP-43 mRNA at levels approximately twice that in nontransfected or vector-transfected cells under control conditions and after treatment with dibutyryl cyclic AMP (diBu-cAMP) or 12-O-tetradecanoylphorbol 13-acetate (TPA) plus diBu-cAMP. Neurite outgrowth after addition of diBu-cAMP was greater in NG-G11 than in control cells. In NG-G11 cells, neurites elongated by treatment with diBu-cAMP for 72 h were maintained after removal of the drug. Treatment with TPA plus diBu-cAMP for 24 h induced neurite outgrowth in NG-G11 cells, although control cells required 72 h. Depolarization by 50 mM KCl induced ACh release in both NG-G11 and control cells treated with diBu-cAMP or TPA/diBu-cAMP. Although removal of the drugs following diBu-cAMP treatment reversed ACh release to nontreated levels in control cells, a high-K(+)-induced level of ACh release remained in NG-G11 cells after removal of diBu-cAMP. ACh release induced by TPA plus diBu-cAMP for 24 h was further enhanced after removal of the drugs in NG-G11 cells, but it was not seen in control cells. These results suggest that levels of GAP-43 mRNA are correlated with neurite maintenance and the level of ACh release. Thus, GAP-43 may be involved in neuronal differentiation in NG108-15 cells.
Kumagai-Tohda
C
C
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Tohda
M
M
Nomura
Y
Y
D000109:Acetylcholine / Q000378:metabolism*; D003994:Bucladesine / Q000494:pharmacology; D002460:Cell Line; D004247:DNA / Q000235:genetics*; D019922:GAP-43 Protein; D008562:Membrane Glycoproteins / Q000235:genetics / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000502:physiology*; D016501:Neurites / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D011189:Potassium Chloride / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection
D019922:GAP-43 Protein; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D003994:Bucladesine; D011189:Potassium Chloride; D004247:DNA; D000109:Acetylcholine; D013755:Tetradecanoylphorbol Acetate