Regional and temporal alterations in DNA fragmentation factor (DFF)-like proteins following experimental brain trauma in the rat.
DNA fragmentation, an early event in neuronal death following traumatic brain injury, may be triggered by the 40-kDa subunit of DNA fragmentation factor (DFF40). DFF40 is typically bound to the 45-kDa subunit of DFF (DFF45), and activation of DFF40 may occur as a result of caspase-3-mediated cleavage of DFF45 into 30- and 11-kDa fragments. In this study, the intracellular distribution of DFF45 and DFF40 was examined following lateral fluid percussion brain injury of moderate severity (2.4-2.7 atm) in male Sprague-Dawley rats. In the cytosolic fraction (S1) of the injured cortex at 2 and 24 h postinjury, significant decreases in the intensities of DFF45-like proteins at 45- and 32-kDa bands and a concomitant increase in the 11-kDa bands were observed (p < 0.05 vs. uninjured controls). A significant decrease in the intensities of the 32-kDa band in the nuclear (P1) fraction of the injured cortex was observed at 30 min and 2 h postinjury (p < 0.01). Concomitantly, a decrease in DFF40 was observed in the cortical S1 fraction at 2 and 24 h (p < 0.05) and in the P1 fraction at 30 min and 2 h postinjury (p < 0.01). In the hippocampus, DFF45 decreased at 30 min in the P1 and 2 h in the S1 fraction (p < 0.05) and recovered by 24 h postinjury, whereas DFF40 was significantly decreased in the S1 and increased in the P1 fraction at both 2 and 24 h (p < 0.01), which indicated a translocation of DFF40 from cytosol to nucleus. These data are the first to demonstrate that changes in DFF proteins occur after brain trauma and suggest that these changes may play a role in apoptotic cell death via caspase-3-DFF45/DFF40-DNA cleavage observed following traumatic brain injury.
Zhang
C
C
Department of Neurosurgery, University of Pennsylvania School of Medicine, Philadelphia 19104-6316, USA.
Raghupathi
R
R
Saatman
K E
KE
LaPlaca
M C
MC
McIntosh
T K
TK
D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D001921:Brain / Q000378:metabolism* / Q000473:pathology*; D001930:Brain Injuries / Q000378:metabolism* / Q000473:pathology*; D002467:Cell Nucleus / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism / Q000473:pathology; D003600:Cytosol / Q000378:metabolism; D053938:DNA Fragmentation; D003851:Deoxyribonucleases / Q000378:metabolism*; D007839:Functional Laterality; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology; D008297:Male; D009928:Organ Specificity; D000075223:Poly-ADP-Ribose Binding Proteins; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D051017:Apoptosis Regulatory Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; D011506:Proteins; C109664:caspase-activated DNase inhibitor; D003851:Deoxyribonucleases; C491882:Dffb protein, rat