ATF3 expression precedes death of spinal motoneurons in amyotrophic lateral sclerosis-SOD1 transgenic mice and correlates with c-Jun phosphorylation, CHOP expression, somato-dendritic ubiquitination and Golgi fragmentation.
To obtain insight into the morphological and molecular correlates of motoneuron degeneration in amyotrophic lateral sclerosis (ALS) mice that express G93A mutant superoxide dismutase (SOD)1 (G93A mice), we have mapped and characterized 'sick' motoneurons labelled by the 'stress transcription factors' ATF3 and phospho-c-Jun. Immunocytochemistry and in situ hybridization showed that a subset of motoneurons express ATF3 from a relatively early phase of disease before the onset of active caspase 3 expression and motoneuron loss. The highest number of ATF3-expressing motoneurons occurred at symptom onset. The onset of ATF3 expression correlated with the appearance of ubiquitinated neurites. Confocal double-labelling immunofluorescence showed that all ATF3-positive motoneurons were immunoreactive for phosphorylated c-Jun. Furthermore, the majority of ATF3 and phospho-c-Jun-positive motoneurons were also immunoreactive for CHOP (GADD153) and showed Golgi fragmentation. A subset of ATF3 and phosphorylated c-Jun-immunoreactive motoneurons showed an abnormal appearance characterized by a number of distinctive features, including an eccentric flattened nucleus, perikaryal accumulation of ubiquitin immunoreactivity, juxta-nuclear accumulation of the Golgi apparatus and the endoplasmic reticulum, and intense Hsp70 immunoreactivity. These abnormal cells were not immunoreactive for active caspase 3. We conclude that motoneurons in ALS-SOD1 mice prior to their death and disappearance experience a prolonged sick phase, characterized by the gradual accumulation of ubiquitinated material first in the neurites and subsequently the cell body.
Vlug
Angela S
AS
Department of Neuroscience, Erasmus University Rotterdam, PO Box 1738, 3000 DR Rotterdam, Netherlands.
Teuling
Eva
E
Haasdijk
Elize D
ED
French
Pim
P
Hoogenraad
Casper C
CC
Jaarsma
Dick
D
D051700:Activating Transcription Factor 3 / Q000235:genetics / Q000378:metabolism*; D000690:Amyotrophic Lateral Sclerosis / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D001324:Autoantigens; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D002452:Cell Count / Q000379:methods; D016923:Cell Death / Q000235:genetics; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000235:genetics; D006056:Golgi Apparatus / Q000473:pathology*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009046:Motor Neurons / Q000378:metabolism*; D010766:Phosphorylation; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D051096:Proto-Oncogene Proteins c-ret / Q000378:metabolism; D013116:Spinal Cord / Q000473:pathology*; D013482:Superoxide Dismutase / Q000235:genetics; D051742:Transcription Factor CHOP / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000378:metabolism
D051700:Activating Transcription Factor 3; C103002:Atf3 protein, mouse; D001324:Autoantigens; C097741:Golgin subfamily A member 2; D018840:HSP70 Heat-Shock Proteins; D008565:Membrane Proteins; D016755:Proto-Oncogene Proteins c-jun; C094135:Rab6 protein; D025801:Ubiquitin; D051742:Transcription Factor CHOP; C109415:SOD1 G93A protein; D013482:Superoxide Dismutase; D051096:Proto-Oncogene Proteins c-ret; D020691:rab GTP-Binding Proteins; D015740:Calcitonin Gene-Related Peptide