title: Tumor necrosis factor alpha stimulates NMDA receptor activity in mouse cortical neurons resulting in ERK-dependent death.
abstract: Multiple cytokines are secreted in the brain during pro-inflammatory conditions and likely affect neuron survival. Previously, we demonstrated that glutamate and tumor necrosis factor alpha (TNFalpha) kill neurons via activation of the N-methyl-d-aspartate (NMDA) and TNFalpha receptors, respectively. This report continues characterizing the signaling cross-talk pathway initiated during this inflammation-related mechanism of death. Stimulation of mouse cortical neuron cultures with TNFalpha results in a transient increase in NMDA receptor-dependent calcium influx that is additive with NMDA stimulation and inhibited by pre-treatment with the NMDA receptor antagonist, DL-2-amino-5-phosphonovaleric acid, or the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate/kainate receptor antagonist, 6,7-dinitroquinoxaline-2,3-dione. Pre-treatment with N-type calcium channel antagonist, omega-conotoxin, or the voltage-gated sodium channel antagonist, tetrodotoxin, also prevents the TNFalpha-stimulated calcium influx. Combined TNFalpha and NMDA stimulation results in a transient increase in activity of extracellular signal-regulated kinases (ERKs) and c-Jun N-terminal kinases (JNKs). Specific inhibition of ERKs but not JNKs is protective against TNFalpha and NMDA-dependent death. Death is mediated via the low-affinity TNFalpha receptor, TNFRII, as agonist antibodies for TNFRII but not TNFRI stimulate NMDA receptor-dependent calcium influx and death. These data demonstrate how microglial pro-inflammatory secretions including TNFalpha can acutely facilitate glutamate-dependent neuron death.
authors.affiliation: Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202, USA.
authors.forename: Javier H
authors.initials: JH
authors.lastname: Jara
authors.forename: Brij B
authors.initials: BB
authors.lastname: Singh
authors.forename: Angela M
authors.initials: AM
authors.lastname: Floden
authors.forename: Colin K
authors.initials: CK
authors.lastname: Combs
mesh_terms: D000818:Animals; D016923:Cell Death; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000502:physiology; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology / Q000502:physiology*
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; C506236:Tnfrsf1a protein, mouse; D014409:Tumor Necrosis Factor-alpha; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases