title: Application of proteasomal inhibitors to mouse sympathetic neurons activates the intrinsic apoptotic pathway.
abstract: Proteasomal dysfunction may play a role in a number of neurodegenerative conditions, and in particular Parkinson's disease (PD) and related Lewy body (LB) diseases. Application of proteasomal inhibitors to neuronal cell culture systems is associated with survival-promoting effects or with cell death depending on the model system. We have applied pharmacological proteasomal inhibitors to cultured neonatal mouse sympathetic neurons in order to investigate whether these catecholaminergic neurons, which are affected in PD, are sensitive to proteasomal inhibition and, if so, which cell death pathway is activated. We report here that proteasomal inhibition leads to apoptotic death of mouse sympathetic neurons. This death is accompanied by caspase 3 activation and cytochrome c release from the mitochondria and is abrogated by caspase inhibition. Bax deletion prevented both cytochrome c release and caspase 3 activation, and also provided complete protection against proteasomal inhibition-induced death. Bcl-2 overexpression achieved a similar survival-promoting effect. There was no change in Bax levels following proteasomal inhibition, suggesting that Bax itself is not regulated by the proteasome in this cell culture system, and that a primary increase in Bax is unlikely to account for death. In contrast, levels of the BH3-only protein, Bim, increased with proteasomal inhibition. We conclude that proteasomal inhibition of mouse sympathetic neurons activates the intrinsic apoptotic pathway involving bcl-2 family members and the mitochondria.
authors.affiliation: Department of Neurology, Columbia University, New York, USA.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Lang-Rollin
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Vekrellis
authors.forename: Qiaohong
authors.initials: Q
authors.lastname: Wang
authors.forename: Hardy J
authors.initials: HJ
authors.lastname: Rideout
authors.forename: Leonidas
authors.initials: L
authors.lastname: Stefanis
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins; D000072224:Bcl-2-Like Protein 11; D015153:Blotting, Western / Q000379:methods; D002352:Carrier Proteins / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D045304:Cytochromes c / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005728:Ganglia, Sympathetic / Q000166:cytology*; D019254:Genes, bcl-2 / Q000502:physiology; D049452:Green Fluorescent Proteins; D007150:Immunohistochemistry / Q000379:methods; D008164:Luminescent Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors*; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D009842:Oligopeptides / Q000494:pharmacology*; D046988:Proteasome Endopeptidase Complex; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2; D012235:Rhodamines / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D013997:Time Factors; D025801:Ubiquitin / Q000378:metabolism; D051028:bcl-2-Associated X Protein
chemical_list: D051017:Apoptosis Regulatory Proteins; C494827:Bax protein, mouse; D000072224:Bcl-2-Like Protein 11; C000606776:Bcl2l11 protein, mouse; D002352:Carrier Proteins; D015853:Cysteine Proteinase Inhibitors; D004791:Enzyme Inhibitors; D008164:Luminescent Proteins; D008565:Membrane Proteins; D009097:Multienzyme Complexes; D009842:Oligopeptides; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012235:Rhodamines; D025801:Ubiquitin; D051028:bcl-2-Associated X Protein; C090535:benzyloxycarbonyl-isoleucyl-glutamyl(O-tert-butyl)-alanyl-leucinal; C401833:tetramethylrhodamine methyl ester; C067713:lactacystin; D049452:Green Fluorescent Proteins; D045304:Cytochromes c; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D000111:Acetylcysteine