Expression of cellular FLICE inhibitory proteins (cFLIP) in normal and traumatic murine and human cerebral cortex.
Cellular Fas-associated death domain-like interleukin-1-beta converting enzyme (FLICE) inhibitory proteins (cFLIPs) are endogenous caspase homologues that inhibit programmed cell death. We hypothesized that cFLIPs are differentially expressed in response to traumatic brain injury (TBI). cFLIP-alpha and cFLIP-delta mRNA were expressed in normal mouse brain-specifically cFLIP-delta (but not cFLIP-alpha) protein was robustly expressed. After controlled cortical impact (CCI), cFLIP-alpha expression increased initially then decreased to control levels at 12 h, increasing again at 24-72 h (P<0.05). cFLIP-delta expression was decreased in brain homogenates by 12 h after CCI, then increased again at 24 to 72 h (P<0.05). cFLIP-delta immunostaining was markedly reduced in injured cortex, but not hippocampus, at 3 to 72 h after CCI. In cortex, reduced cFLIP-delta staining was found in TUNEL-positive cells, but in hippocampus TUNEL-positive cells expressed cFLIP-delta immunoreactivity. cFLIP-delta was increased in a subset of reactive astrocytes in pericontusional cortex and hippocampus at 48 to 72 h. Low levels of both cFLIP isoforms were detected in human cortical tissue with no TBI, from four patients undergoing brain surgery for epilepsy and <24 h post mortem from three patients without CNS pathologic assessment. In cortical tissue surgically removed <18 h after severe TBI (n=3), cFLIP-alpha expression was increased relative to epilepsy controls (P<0.05) but not relative to post-mortem controls. The data suggest differential spatial and temporal regulation of cFLIP-alpha and cFLIP-delta expression that may influence the magnitude of cell death and further implicate programmed mechanisms of cell death after TBI.
Hainsworth
Atticus H
AH
Neuroscience Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA.
Bermpohl
Daniela
D
Webb
Tania E
TE
Darwish
Ribal
R
Fiskum
Gary
G
Qiu
Jianhua
J
McCarthy
Deirdre
D
Moskowitz
Michael A
MA
Whalen
Michael J
MJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D015153:Blotting, Western; D001923:Brain Chemistry / Q000502:physiology; D001930:Brain Injuries / Q000378:metabolism*; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D002540:Cerebral Cortex / Q000293:injuries* / Q000378:metabolism*; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007202:Indicators and Reagents; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D007536:Isomerism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008875:Middle Aged; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction
D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; C506387:Cflar protein, mouse; D018076:DNA, Complementary; D007202:Indicators and Reagents; D047908:Intracellular Signaling Peptides and Proteins; D012333:RNA, Messenger