Differential susceptibility to neurotoxicity mediated by neurotrophins and neuronal nitric oxide synthase.
NMDA neurotoxicity, which is mediated, in part, by formation of nitric oxide (NO) via activation of neuronal NO synthase (nNOS), is modulated by neurotrophins. nNOS expression in rat and mouse primary neuronal cultures grown on a glial feeder layer is significantly less than that of neurons grown on a polyornithine (Poly-O) matrix. Neurotrophins markedly increase the number of nNOS neurons, nNOS protein, and NOS catalytic activity and enhance NMDA neurotoxicity via NO-dependent mechanisms when neurons are grown on glial feeder layers. In contrast, when rat or mouse primary cortical neurons are grown on a Poly-O matrix, neurotrophins have no influence on nNOS neuronal number or NOS catalytic activity and reduce NMDA neurotoxicity. Primary neuronal cultures from mice lacking nNOS grown on a glial feeder layer fail to respond to neurotrophin-mediated enhancement of neurotoxicity. Together, these results indicate that nNOS expression and NMDA NO-mediated neurotoxicity are dependent, in part, on the culture paradigm, and neurotrophins regulate the susceptibility to NMDA neurotoxicity via modulation of nNOS. Furthermore, these results support the idea that NMDA neurotoxicity in culture is critically dependent on the developmental state of the neurons being assessed and suggest that, when cortical neurons are cultured on a glial feeder layer, they do not reach nearly as mature a phenotype as when grown on a Poly-O matrix.
Samdani
A F
AF
Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
Newcamp
C
C
Resink
A
A
Facchinetti
F
F
Hoffman
B E
BE
Dawson
V L
VL
Dawson
T M
TM
D000818:Animals; D001120:Arginine / Q000494:pharmacology; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology* / Q000196:embryology; D018920:Coculture Techniques; D004622:Embryo, Mammalian; D005333:Fetus; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D051100:Glial Cell Line-Derived Neurotrophic Factor; D007700:Kinetics; D051379:Mice; D008810:Mice, Inbred C57BL; D016202:N-Methylaspartate / Q000037:antagonists & inhibitors / Q000633:toxicity*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000494:pharmacology; D009457:Neuroglia / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D009498:Neurotoxins; D020933:Neurotrophin 3; D019001:Nitric Oxide Synthase / Q000096:biosynthesis / Q000172:deficiency / Q000378:metabolism*; D009599:Nitroprusside / Q000494:pharmacology; D010455:Peptides; D051381:Rats; D017207:Rats, Sprague-Dawley
D019208:Brain-Derived Neurotrophic Factor; C495040:Gdnf protein, mouse; C495041:Gdnf protein, rat; D051100:Glial Cell Line-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D009498:Neurotoxins; D020933:Neurotrophin 3; D010455:Peptides; D009599:Nitroprusside; C008973:polyornithine; D016202:N-Methylaspartate; D001120:Arginine; D019001:Nitric Oxide Synthase; C073922:neurotrophin 4; D019331:NG-Nitroarginine Methyl Ester