title: Acute and chronic alterations in calcium homeostasis in 3-nitropropionic acid-treated human NT2-N neurons.
abstract: 3-Nitropropionic acid (3-NP), an irreversible inhibitor of succinate dehydrogenase, induced ATP depletion and both necrosis and apoptosis in human NT2-N neurons. Necrosis occurred predominantly within the first two days, and increased in a dose-dependent fashion with the concentration of 3-NP, whereas apoptosis was observed after 24 h or later at a similar rate in 0.1 mM and 5 mM 3-NP. We focused our efforts on intracellular calcium homeostasis during the first 48 h in 1 mM 3-NP, a period during which 10% of the neurons died by necrosis and 3% by apoptosis. All NT2-N neurons showed a stereotyped [Ca(2+)](i) rise, from 48+/-2 to 140+/-12 nM (mean +/-S.E.M.), during the first 2 h in 3-NP. Despite severe ATP depletion, however, [Ca(2+)](i) remained above 100 nM in only 17% and 25% of the NT2-N neurons after 24 and 48 h in 3-NP, respectively, indicating that most neurons were able to recover from acute [Ca(2+)](i) rise, and suggesting that chronic [Ca(2+)](i) dysregulation is a better indicator of subsequent necrosis. Blockade of N-methyl-D-aspartate-glutamate receptor by MK-801 substantially ameliorated 3-NP-induced ATP depletion, subsequent chronic [Ca(2+)](i) elevation, and survival. Moreover, xestospongin C, an inhibitor of endoplasmic reticulum Ca(2+) release, enhanced the capacity of NT2-N neurons to maintain [Ca(2+)](i) homeostasis and resist necrosis while subjected to sustained energy deprivation. As far as we know, this report is the first to employ human neurons to study the pathophysiology of 3-NP neurotoxicity.
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: W-T
authors.initials: WT
authors.lastname: Lee
authors.forename: T
authors.initials: T
authors.lastname: Itoh
authors.forename: D
authors.initials: D
authors.lastname: Pleasure
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects* / Q000378:metabolism*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D020287:In Situ Nick-End Labeling; D047028:Macrocyclic Compounds; D008928:Mitochondria / Q000378:metabolism; D009336:Necrosis; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism* / Q000473:pathology; D009498:Neurotoxins / Q000494:pharmacology*; D009574:Nitro Compounds; D010080:Oxazoles / Q000494:pharmacology; D011422:Propionates / Q000494:pharmacology*; D017470:Receptors, Glutamate / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism; D013385:Succinate Dehydrogenase / Q000037:antagonists & inhibitors; D013997:Time Factors; D014407:Tumor Cells, Cultured
chemical_list: D015220:Calcium Channels; D004791:Enzyme Inhibitors; D047028:Macrocyclic Compounds; D009498:Neurotoxins; D009574:Nitro Compounds; D010080:Oxazoles; D011422:Propionates; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C108644:xestospongin A; D016291:Dizocilpine Maleate; D000255:Adenosine Triphosphate; D013385:Succinate Dehydrogenase; C015392:3-nitropropionic acid; D002118:Calcium