title: Tumor necrosis factor alpha and interferon gamma cooperatively induce oxidative stress and motoneuron death in rat spinal cord embryonic explants.
abstract: The accumulation of reactive microglia in the degenerating areas of amyotrophic lateral sclerosis (ALS) tissue is a key cellular event creating a chronic inflammatory environment that results in motoneuron death. We have developed a new culture system that consists in rat spinal cord embryonic explants in which motoneurons migrate outside the explant, growing as a monolayer in the presence of glial cells. The proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) have been proposed to be involved in ALS-linked microglial activation. In our explants, the combined exposure to these cytokines resulted in an increased expression of the pro-oxidative enzymes inducible nitric oxide synthase (iNOS), the catalytic subunit of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, gp91(phox) and cyclooxygenase-2 (COX-2), as compared to each cytokine alone. This effect was related to their cooperation in the activation of the transcription factor nuclear factor kappa B (NF-kappaB). TNF-alpha and IFN-gamma also cooperated to promote protein oxidation and nitration, thus increasing the percentage of motoneurons immunoreactive for nitrotyrosine. Apoptotic motoneuron death, measured through annexin V-Cy3 and active caspase-3 immunoreactivities, was also found cooperatively induced by TNF-alpha and IFN-gamma. Interestingly, these cytokines did not affect the viability of purified spinal cord motoneurons in the absence of glial cells. It is proposed that the proinflammatory cytokines TNF-alpha and IFN-gamma have cooperative/complementary roles in inflammation-induced motoneuron death.
authors.affiliation: Grup de Neurobiologia Cel.lular, Institut Universitari d'Investigacions en Ciències de la Salut/Departament de Biologia, Universitat de les Illes Balears, Cra. de Valldemossa, km 7.5, E-07122 Palma de Mallorca, Illes Balears, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Mir
authors.forename: V J
authors.initials: VJ
authors.lastname: Asensio
authors.forename: L
authors.initials: L
authors.lastname: Tolosa
authors.forename: M
authors.initials: M
authors.lastname: Gou-Fabregas
authors.forename: R M
authors.initials: RM
authors.lastname: Soler
authors.forename: J
authors.initials: J
authors.lastname: Lladó
authors.forename: G
authors.initials: G
authors.lastname: Olmos
mesh_terms: D000818:Animals; D017209:Apoptosis; D002465:Cell Movement; D002470:Cell Survival; D003470:Culture Media; D004622:Embryo, Mammalian; D007371:Interferon-gamma / Q000494:pharmacology / Q000502:physiology*; D017628:Microglia / Q000187:drug effects / Q000502:physiology; D009046:Motor Neurons / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000166:cytology* / Q000187:drug effects; D046509:Tissue Culture Techniques; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology / Q000502:physiology*
chemical_list: D003470:Culture Media; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D007371:Interferon-gamma