title: Trophic factors attenuate nitric oxide mediated neuronal and axonal injury in vitro: roles and interactions of mitogen-activated protein kinase signalling pathways.
abstract: Inflammation in the central nervous system occurs in diseases such as multiple sclerosis and leads to axon dysfunction and destruction. Both in vitro and in vivo observations have suggested an important role for nitric oxide (NO) in mediating inflammatory axonopathy. The purposes of this study were to model inflammatory axonopathy in vitro and identify modulators of the process. Rat cortical neurones were cultured and exposed to an NO-donor plus potential protective factors. Cultures were then assessed for neuronal survival, axon survival and markers of intracellular signalling pathways. The NO-donor produced dose-dependent neuronal loss and a large degree of axon destruction. Oligodendrocyte conditioned medium (OCM) and insulin-like growth factor type-1 (IGF-1), but not glial cell line-derived neurotrophic factor (GDNF), improved survival of neurones exposed to NO donors. In addition p38 MAP kinase was activated by NO exposure and inhibition of p38 signalling led to neuronal and axonal survival effects. OCM and IGF-1 (but not GDNF) reduced p38 activation in NO-exposed cortical neurones. OCM, IGF-1 and GDNF improved axon survival in cultures exposed to NO, a process dependent on mitogen-activated protein kinase/extracellular signal-related kinase signalling. This study emphasizes that different mechanisms may underlie neuronal/axonal destructive processes, and suggests that trophic factors may modulate NO-mediated neurone/axon destruction via specific pathways.
authors.affiliation: Department of Clinical Neurosciences and Centre for Brain Repair, University of Cambridge, Forvie Site, Robinson Way, Cambridge CB2 2PY, UK. aw255@cam.ac.uk
authors.forename: Alastair
authors.initials: A
authors.lastname: Wilkins
authors.forename: Alastair
authors.initials: A
authors.lastname: Compston
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D018920:Coculture Techniques; D017077:Culture Media, Conditioned / Q000494:pharmacology; D019610:Cytoprotection / Q000187:drug effects / Q000502:physiology; D003711:Demyelinating Diseases / Q000378:metabolism* / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D004660:Encephalitis / Q000378:metabolism* / Q000503:physiopathology; D051100:Glial Cell Line-Derived Neurotrophic Factor; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D008959:Models, Neurological; D009414:Nerve Growth Factors / Q000378:metabolism* / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000037:antagonists & inhibitors / Q000633:toxicity; D051381:Rats; D014855:Wallerian Degeneration / Q000378:metabolism* / Q000503:physiopathology; D048051:p38 Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism
chemical_list: D017077:Culture Media, Conditioned; C495041:Gdnf protein, rat; D051100:Glial Cell Line-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; D020030:Nitric Oxide Donors; D009569:Nitric Oxide; D007334:Insulin-Like Growth Factor I; D048051:p38 Mitogen-Activated Protein Kinases