Biochemistry and Molecular Biology

Our long-term goals are to understand the mechanisms of neuronal cell death and deficits associated with both acute and chronic trauma to the central nervous system at a molecular and cellular level. We have developed an array of interventions ranging from modified liposomal gene transfer, endogenous receptor antagonists and gene specific “decoy” inhibition of transcription factor binding to promoter sites as intervention approaches to therapy at the transcriptional level. Our hypothesis is that oxidative stress in the nervous system, caused by chronic or acute trauma, triggers inflammatory responses that result in the uncoupling of gene networks responsible for cell viability and function that result in the altered phenotypes associated with neural deficits present in injury, aging and Alzheimer’s Disease. In addition, we hypothesize that trauma-induced phosphorylation events affect organelle occupancy by proteins regulating cell death. For example, inflammatory cascades activated by trauma have genotoxic and energetic consequences that activate stress response genes via the NF-B transcription factor. Transcription factors bind to cognate DNA sequences that regulate stress response gene expression essential to survival and function. We believe that transcription factor binding to cognate

Figure. Demonstration of intranuclear
and perinuclear BAX in CNS neurons.
Chromosome, mitochondria/ER markers.

DNA sequences is finely tuned by the specificity of the sequence, position within a promoter and protein-protein interactions with other sites on a promoter. Our ongoing studies focus on: the ß-amyloid generating BACE enzyme, the Bcl-protein family of genes, COX-2, iNOS, and the IL-1 cytokine. We rely on in vitro and working animal models for perinatal ischemia, spinal cord injury, and β-amyloid toxicity in rats, mice and guinea pigs. In vitro models used are the PC12 line and primary cultures derived from fetal and neonatal brain. We also rely on murine transgenic models of Alzheimer’s Disease and focal stroke in the aged rat. We use in vivo MRI techniques to assess damage and vascular changes in brain and spinal cordin addition to confocal immunocytochemistry to assess organelle function in response to oxidative stress. In vitro reporter constructs and transgenic models suitable to unraveling the role of the NF-kB transcription factor in transcriptional regulation of select genes are also used. In addition, we are applying genomic, proteomic and bioinformatics approaches to analyses of time course studies of post-traumatic injury response. Our animal studies look at outcomes to trauma and therapeutic molecular interventions in terms of locomotor functional recovery, cognitive and sensory outcomes, including central neuropathic pain. We also carry out gene transfer treatments for thermal trauma. Studies are supported in part by the NINDS, NICHD, NSF Israel/US Bilateral Agreement, Shriners and Clayton Foundations, and the Mission Connect Consortium and Sealy Program. Collaborative efforts include the Oregon Health Science Center, Baylor College of Medicine, University of Texas Houston Medical School, University of Leipzig, Germany, University of Montpellier, France, and Ben-Gurion University, Israel.