title: Nitric oxide and cyclic nucleotide signal transduction modulates synaptic vesicle turnover in human model neurons.
abstract: The human Ntera2 (NT2) teratocarcinoma cell line can be induced to differentiate into post-mitotic neurons. Here, we report that the human NT2 neurons generated by a spherical aggregate cell culture method express increasing levels of typical pre-synaptic proteins (synapsin and synaptotagmin I) along the neurite depending on the length of in vitro culture. By employing an antibody directed against the luminal domain of synaptotagmin I and the fluorescent dye N-(3-triethylammoniumpropyl)-4-(4-(dibutylamino)styryl)pyridinium dibromide, we show that depolarized NT2 neurons display calcium-dependent exo-endocytotic synaptic vesicle recycling. NT2 neurons express the neuronal isoform of neuronal nitric oxide synthase and soluble guanylyl cyclase (sGC), the major receptor for nitric oxide (NO). We tested whether NO signal transduction modulates synaptic vesicle turnover in human NT2 neurons. NO donors and cylic guanosine-monophosphate analogs enhanced synaptic vesicle recycling while a sGC inhibitor blocked the effect of NO donors. Two NO donors, sodium nitroprusside, and and N-Ethyl-2-(1-ethyl-2-hydroxy-2-nitrosohydrazino) ethanamine evoked vesicle exocytosis which was partially blocked by the sGC inhibitor. The activator of adenylyl cyclase, forskolin, and a cAMP analog induced synaptic vesicle recycling and exocytosis via a parallel acting protein kinase A pathway. Our data from NT2 neurons suggest that NO/cyclic nucleotide signaling pathways may facilitate neurotransmitter release in human brain cells.
authors.affiliation: Division of Cell Biology, Institute of Physiology, University of Veterinary Medicine Hannover, Hannover, Germany.
authors.forename: Million Adane
authors.initials: MA
authors.lastname: Tegenge
authors.forename: Michael
authors.initials: M
authors.lastname: Stern
authors.forename: Gerd
authors.initials: G
authors.lastname: Bicker
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D005576:Colforsin / Q000494:pharmacology; D006152:Cyclic GMP / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005089:Exocytosis / Q000187:drug effects; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D009603:Nitroso Compounds / Q000494:pharmacology; D009712:Nucleotides, Cyclic / Q000378:metabolism*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013449:Sulfonamides / Q000494:pharmacology; D016704:Synapsins / Q000378:metabolism; D013572:Synaptic Vesicles / Q000187:drug effects / Q000378:metabolism*; D050863:Synaptotagmin I / Q000378:metabolism; D018243:Teratocarcinoma; D013997:Time Factors
chemical_list: D004791:Enzyme Inhibitors; C073804:FM1 43; D007546:Isoquinolines; C489788:MAP2 protein, human; D008869:Microtubule-Associated Proteins; C118603:NOC 12; D009603:Nitroso Compounds; D009712:Nucleotides, Cyclic; D010726:Phosphodiesterase Inhibitors; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D013449:Sulfonamides; D016704:Synapsins; D050863:Synaptotagmin I; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D009569:Nitric Oxide; D052248:Nitric Oxide Synthase Type I; D006152:Cyclic GMP; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D015056:1-Methyl-3-isobutylxanthine