Traumatic brain injury (TBI) is the leading cause of death among individuals under the age of 45 in the United States and survivors are faced with chronic brain damage leading to debilitating behavioral dysfunction. Brain damage and behavioral dysfunction may be, in part, due to neuronal death following TBI. The hypothesis to be tested in this proposal is that post-traumatic neuronal cell death is a result of activation of the pro-apoptotic caspase family of cysteine proteases. The objectives of this proposal are to elucidate (1) the association between neuronal death in experimental TBI and in postmortem tissue from head-injured patients and the activation of the """"""""executor"""""""" caspase-3, (2) whether caspase-3 activation occurs directly as a result of activation of the """"""""initiator"""""""" caspase-8, and/or indirectly as a result of mitochondrial pathway which requires Bax translocation, cytochrome c release and caspase-9 activation, (3) whether caspase-8 activation occurs as a result of activation of the tumor necrosis factor family of death receptors, (4) the role of Bax in mediating trauma-induced caspase-9 activation and subsequent caspase-3 activation and cell death, and (5) whether post-traumatic inhibition of caspases-3, -8 and -9 will reduce the extent of injury-induced cell death. Immunoblot and immunohistochemical analyses using specific and selective antibodies will be utilized to temporal and regional patterns of activation of caspases-3, -8 and -9, resdistribution of Bax and cytochrome c, and, apoptotic neuronal damage, as indicated by the presence of cellular DNA fragmentation and morphologic analyses. Mice deficient in TNF will be used to determine the role of TNF in mediating activation of caspases-8 and -3, and eventual apoptotic cell death by using immunoblot, immunohistochemical and histological analyses. The role of Bax in trauma-induced activation of caspase-9 and -3, cytochrome c redistribution, apoptotic neuronal death and behavioral dysfunction will be examined using immunoblot and immunohistochemical techniques, and by testing cognitive and motor function in brain-injured, Bax-deficient mice, followed by histological analysis of cell death. The effect of post-traumatic treatment with peptide inhibitors selective for caspases-3 (DEVD), -8 (IETD) and -9 (LEHD), on the extent of regional cell death and behavioral dysfunction will provide the mechanistic link between caspase activation and TBI-induced pathology.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS041561-03
Application #
6776390
Study Section
Special Emphasis Panel (ZRG1-BDCN-1 (01))
Program Officer
Pancrazio, Joseph J
Project Start
2002-06-01
Project End
2007-05-31
Budget Start
2004-06-01
Budget End
2005-05-31
Support Year
3
Fiscal Year
2004
Total Cost
$369,468
Indirect Cost
Name
Drexel University
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
002604817
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
DiLeonardi, Ann Mae; Huh, Jimmy W; Raghupathi, Ramesh (2009) Impaired axonal transport and neurofilament compaction occur in separate populations of injured axons following diffuse brain injury in the immature rat. Brain Res 1263:174-82
Huh, Jimmy W; Widing, Ashley G; Raghupathi, Ramesh (2008) Midline brain injury in the immature rat induces sustained cognitive deficits, bihemispheric axonal injury and neurodegeneration. Exp Neurol 213:84-92
Conte, Valeria; Raghupathi, Ramesh; Watson, Deborah J et al. (2008) TrkB gene transfer does not alter hippocampal neuronal loss and cognitive deficits following traumatic brain injury in mice. Restor Neurol Neurosci 26:45-56
Raghupathi, Ramesh; Huh, Jimmy W (2007) Diffuse brain injury in the immature rat: evidence for an age-at-injury effect on cognitive function and histopathologic damage. J Neurotrauma 24:1596-608
Serbest, Gulyeter; Burkhardt, Matthew F; Siman, Robert et al. (2007) Temporal profiles of cytoskeletal protein loss following traumatic axonal injury in mice. Neurochem Res 32:2006-14
Huh, Jimmy W; Raghupathi, Ramesh (2007) Chronic cognitive deficits and long-term histopathological alterations following contusive brain injury in the immature rat. J Neurotrauma 24:1460-74
Shimizu, Saori; Khan, Muhammad Z; Hippensteel, Randi L et al. (2007) Role of the transcription factor E2F1 in CXCR4-mediated neurotoxicity and HIV neuropathology. Neurobiol Dis 25:17-26
Huh, Jimmy W; Widing, Ashley G; Raghupathi, Ramesh (2007) Basic science;repetitive mild non-contusive brain trauma in immature rats exacerbates traumatic axonal injury and axonal calpain activation: a preliminary report. J Neurotrauma 24:15-27
Saatman, Kathryn E; Feeko, Kristofer J; Pape, Rebecca L et al. (2006) Differential behavioral and histopathological responses to graded cortical impact injury in mice. J Neurotrauma 23:1241-53
Huh, Jimmy W; Franklin, Michael A; Widing, Ashley G et al. (2006) Regionally distinct patterns of calpain activation and traumatic axonal injury following contusive brain injury in immature rats. Dev Neurosci 28:466-76

Showing the most recent 10 out of 17 publications