Delayed neuronal death occurs in experimental models of traumatic brain injury (TBI) and may contribute to secondary brain injury in humans as well. In response to brain injury, several endogenous neuroprotective genes and proteins are induced and may play important roles in neuronal survival. We have shown that members of the stress protein and bcl-2- related apoptosis-suppressor gene families are expressed in brain after TBI. Furthermore, members of these gene families have been shown to have beneficial effects in vitro, and thus are logical candidate neuroprotective genes. Our HYPOTHESIS is that neuroprotective genes and proteins are expressed and promote neuronal survival. and reduce secondary damage after TBI.
Our specific AIMS are: 1) Further characterize the cellular, regional, and temporal expression of the stress proteins (hsp72, grp 75, and grp 78); and the anti-apoptotic genes (bcl-2, bcl-x-long, and bc-beta; after TBI, using in situ hybridization, Norther and Western analysis, and immunocytochemistry; (2) Determine if specific overexpression of bcl-2 using herpes simplex virus- vector gene transfer in vivo reduces neuropathology (contusion, volume, histology) and improves functional outcomes (motor and cognitive testing) after TBI; and 3) Determine if specific inhibition of translation of bcl-2 protein using intraventricular antisense oligodeoxynucleotide treatment in vivo exacerbates secondary brain injury as assessed by neuropathologic (contusion, volume, histology) and functional outcome (motor and cognitive testing) measurements after TBI. Based on our preliminary data, we have chosen to initially study the role of bcl-2. Other endogenous neuroprotective genes like play a role after TBI as well, therefore we further aim to similarly study other candidate genes. These studies will allow us to confirm the role of candidate neuroprotective genes, and to determine whether their expression, alone or in combination, is sufficient to affect morbidity following TBI in vivo. Confirming the ability of these candidate endogenous neuroprotective genes to prevent secondary brain injury in vivo may lead to the development of novel and contemporary neuroprotective agents for treatment of head injury. This proposal is intended to provide for the research experience and career development of the applicant involving the mechanisms of, and novel, targeted therapeutic strategies for, the treatment of acute brain injury. The Departments of Neurology and Anesthesiology/Critical Care Medicine, Safar Center for Resuscitation Research, and Brain Trauma Research Center at the University of Pittsburgh provide a rich environment for the study of experimental and clinical brain injury, and have a strong commitment to foster meaningful and contemporary research in this field.
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