title: Time-lapse imaging of p65 and IκBα translocation kinetics following Ca2+-induced neuronal injury reveals biphasic translocation kinetics in surviving neurons.
abstract: The transcription factor nuclear factor-κB (NF-κB) regulates neuronal differentiation, plasticity and survival. It is well established that excitatory neurotransmitters such as glutamate control NF-κB activity. Glutamate receptor overactivation is also involved in ischemic- and seizure-induced neuronal injury and neurodegeneration. However, little is known at the single cell-level how NF-κB signaling relates to neuronal survival during excitotoxic injury. We found that silencing of p65/NF-κB delayed N-methyl-d-aspartate (NMDA)-induced excitotoxic injury in hippocampal neurons, suggesting a functional role of p65 in excitotoxicity. Time-lapse imaging of p65 and its inhibitor IκBα using GFP and Cerulean fusion proteins revealed specific patterns of excitotoxic NF-κB activation. Nuclear translocation of p65 began on average 8±3min following 15min of NMDA treatment and was observed in up to two thirds of hippocampal neurons. Nuclear translocation of IκBα preceded that of p65 suggesting independent translocation processes. In surviving neurons, the onset of p65 nuclear export correlated with mitochondrial membrane potential recovery. Dying neurons exhibited persistent nuclear accumulation of p65-eGFP until plasma membrane permeabilization. Our data demonstrate an important role for p65 activation kinetics in neuronal cell death decisions following excitotoxic injury.
authors.affiliation: Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin 2, Ireland.
authors.forename: Robert
authors.initials: R
authors.lastname: Schwamborn
authors.affiliation: Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin 2, Ireland.
authors.forename: Heiko
authors.initials: H
authors.lastname: Düssmann
authors.affiliation: Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin 2, Ireland. Electronic address: hgkoenig@rcsi.ie.
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: König
authors.affiliation: Department of Physiology and Medical Physics, Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland, 123 Saint Stephen's Green, Dublin 2, Ireland. Electronic address: prehn@rcsi.ie.
authors.forename: Jochen H M
authors.initials: JHM
authors.lastname: Prehn
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects; D002466:Cell Nucleolus / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D057809:HEK293 Cells; D006624:Hippocampus / Q000166:cytology; D006801:Humans; D016202:N-Methylaspartate / Q000494:pharmacology; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D029543:Nucleocytoplasmic Transport Proteins / Q000235:genetics / Q000378:metabolism*; D016716:PC12 Cells; D021381:Protein Transport / Q000187:drug effects / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction
chemical_list: D018690:Excitatory Amino Acid Agonists; D016328:NF-kappa B; D009363:Neoplasm Proteins; D029543:Nucleocytoplasmic Transport Proteins; D034741:RNA, Small Interfering; C063447:p65 oncofetal mRNA transport protein, rat; D016202:N-Methylaspartate; D002118:Calcium
keywords: Excitotoxicity; NF-κB; NMDA; Single cell imaging; TMRM