Rapid upregulation of caspase-3 in rat spinal cord after injury: mRNA, protein, and cellular localization correlates with apoptotic cell death.
Although the precise mechanisms explaining loss of, and failure to regain, function after spinal cord injury are unknown, there is increasing interest in the role of "secondary cell death." One prevalent theme in cell loss in other regions of the CNS involves apoptosis executed by the intracellular caspase proteases. A recent study demonstrated that spinal cord injury rapidly increased the activation of caspase-3. Our previous studies demonstrated peak apoptosis in three of four cellular compartments 3 days after controlled contusion in the rat. We have extended these analyses to include enzyme and substrate studies of caspase subfamilies both in rostral and in caudal adjacent segments compared to the lesion site. Although presumed activation of programmed proenzyme is considered the mechanism for enhanced caspases, our novel analyses were designed to detect upregulation of gene expression. We surveyed traumatically injured spinal cord for caspase family messages with a modified differential mRNA display approach and found that the caspase-3 (CASP3) message was present and upregulated severalfold after injury. Our results clearly demonstrate that cell death in the spinal cord occurs after posttranslational activation of caspases that follow, at least for caspase-3, initial upregulation of CASP3 mRNA levels.
Citron
B A
BA
Neurobiology Research Laboratory, Department of Veterans Affairs Medical Center, Kansas City, Missouri, 64128, USA.
Arnold
P M
PM
Sebastian
C
C
Qin
F
F
Malladi
S
S
Ameenuddin
S
S
Landis
M E
ME
Festoff
B W
BW
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D001710:Biotin; D002352:Carrier Proteins / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000235:genetics / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D017403:In Situ Hybridization; D008297:Male; D008840:Microfilament Proteins / Q000378:metabolism; D017628:Microglia / Q000378:metabolism; D009046:Motor Neurons / Q000201:enzymology / Q000473:pathology; D009842:Oligopeptides; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D011506:Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000201:enzymology* / Q000473:pathology*; D013119:Spinal Cord Injuries / Q000378:metabolism* / Q000473:pathology*; D013379:Substrate Specificity; D013049:Spectrin
D001710:Biotin; D002352:Carrier Proteins; D053148:Caspase 3; D020169:Caspases; D015853:Cysteine Proteinase Inhibitors; D008840:Microfilament Proteins; D009842:Oligopeptides; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D011506:Proteins; D012333:RNA, Messenger; D013049:Spectrin; C110772:benzoylcarbonyl-aspartyl-glutamyl-valyl-aspartyl-fluoromethyl ketone; C499322:Parp1 protein, rat; C505410:Casp3 protein, rat