title: Long term proteasome inhibition does not preferentially afflict motor neurons in organotypical spinal cord cultures.
abstract: Ubiquitinated inclusions are a constant feature of amyotrophic lateral sclerosis (ALS). It has been hypothesised that these inclusions reflect overload or failure of the ubiquitin-proteasome system, and that this failure contributes to the degeneration of motor neurons. In the present study we have examined the effect of low concentrations of proteasome inhibitors on protein aggregation and viability of neurons in organotypical spinal cord cultures. We found a dose-dependent degeneration of neurons after a one-week exposure to the proteasome inhibitors lactacystin and epoxomicin. Neuronal degeneration was associated with an increase in poly-ubiquitination, consistent with failure of the ubiquitin-proteasome system. Proteasome inhibition caused degeneration of both motor neurons and interneurons, and no difference in survival between motor neurons and interneurons was observed. Since protein aggregation may particularly play a role in ALS patients with superoxide dismutase 1 (SOD1) mutations, we have compared the effect of proteasome inhibition between spinal cord cultures from non-transgenic and SOD1(G93A) transgenic mice. There was no difference between the viability of motor neurons from transgenic and non-transgenic mice.
authors.affiliation: Department of Neuroscience, Erasmus MC, PO Box 1738, 3000 DR Rotterdam, The Netherlands.
authors.forename: Angela S
authors.initials: AS
authors.lastname: Vlug
authors.forename: Dick
authors.initials: D
authors.lastname: Jaarsma
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D051700:Activating Transcription Factor 3; D000818:Animals; D002452:Cell Count; D002470:Cell Survival / Q000187:drug effects; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D007150:Immunohistochemistry / Q000379:methods; D007395:Interneurons / Q000187:drug effects; D051379:Mice; D008822:Mice, Transgenic; D009046:Motor Neurons / Q000187:drug effects* / Q000502:physiology; D016900:Neurofilament Proteins / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology*; D009924:Organ Culture Techniques; D011480:Protease Inhibitors / Q000494:pharmacology*; D013116:Spinal Cord / Q000166:cytology*; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D051700:Activating Transcription Factor 3; C103002:Atf3 protein, mouse; D016900:Neurofilament Proteins; D009842:Oligopeptides; D011480:Protease Inhibitors; D014157:Transcription Factors; D025801:Ubiquitin; C067713:lactacystin; C109415:SOD1 G93A protein; D013482:Superoxide Dismutase; D002795:Choline O-Acetyltransferase; D000111:Acetylcysteine; C078846:epoxomicin