Article

Proteasomal inhibition-induced inclusion formation and death in cortical neurons require transcription and ubiquitination.

Department of Neurology, Columbia University, New York, New York 10032, USA.
Molecular and Cellular Neuroscience (impact factor: 3.66). 11/2002; 21(2):223-38. DOI:10.1006/mcne.2002.1173 pp.223-38
Source: PubMed

ABSTRACT Increasing evidence suggests that proteasomal dysfunction plays a role in the pathogenesis of Lewy body diseases. We have used pharmacological inhibitors of the proteasome to model proteasomal dysfunction in cultured rat cortical neurons. Proteasomal inhibition induced apoptotic death and formation of cytoplasmic ubiquitinated inclusions, which were present only in viable neurons. Actinomycin D, but not a caspase inhibitor, prevented inclusion formation, whereas both agents inhibited cell death. alpha-Synuclein and thioflavin S staining were found within the inclusions. alpha-Synuclein, however, did not appear to be ubiquitinated or aggregated. A dominant-negative mutant of an E2 ubiquitin-conjugating enzyme, cdc34, prevented inclusion formation and attenuated cell death. Our results suggest that in cortical neurons: (a) proteasomal dysfunction plays a role in formation of ubiquitin/alpha-synuclein-positive inclusions, (b) inclusion formation is an active cell process requiring transcription, and (c) ubiquitination of certain proteins is required for inclusion formation and may participate in neuronal death.

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Keywords

Actinomycin D
 
active cell process
 
agents inhibited cell death
 
attenuated cell death
 
certain proteins
 
cortical neurons
 
cultured rat cortical neurons
 
cytoplasmic ubiquitinated inclusions
 
dominant-negative mutant
 
E2 ubiquitin-conjugating enzyme
 
inclusion formation
 
Increasing evidence
 
Lewy body diseases
 
model proteasomal dysfunction
 
neuronal death
 
pharmacological inhibitors
 
proteasomal dysfunction
 
Proteasomal inhibition induced apoptotic death
 
ubiquitinated
 
viable neurons
 

Hardy J Rideout