Neuronal apopotosis and degeneration is common to a wide range of severe diseases in the nervous system including traumatic brain injury, focal ischemia, Parkinsons's disease and Alzheimers disease. In addition to the control of basic physiological processes, the NF-kB family of transcription factors have emerged as major regulators of cell life and death in many systems. Since their recent discovery in,the nervous system, both pro- and anti-apoptotic actions have been attributed to NF-kB. Our proposal will address the possibility that different mechanisms of neuronal stimulation may result in differences in the time course, degree, and subunit composition of activated neuronal NF-kB. These differences, in turn, could explain contrasting physiologic functions of neuronal NFkB in disparate settings and might lead to the development of strategies to therapeutically regulate NF-kB activation. We have selected the hippocampus as our model system for studying neuronal NF-kB because it is a well-defined area of both physiological (learning and memory) as well as pathological (stroke, Alzheimers disease) neuronal function. Our studies will use hippocampal tissue from both adult mice and neonates as well as several transgenic and knockout lines. We will identify the NF-kB family members present in hippocampal neurons and define the types of stimulation which lead to their activation. We will investigate representative neurotransmitters, neurotrophins, and cell adhesion molecules for their ability to activate neuronal NF-kB using electromobility shift assays and a kB-reporter construct. In addition, we will use a fluorescently labeled NF-kB subunit to examine the subcellular localization of NF-kB and determine its ability to translocate to the nucleus from neuronal processes following different stimulation parameters. We will examine if levels of synaptic activity within the normal physiological range functionally regulate NFkB, or if significant activation occurs only in response to stressful stimuli, Can the pattern of NFkB activation encode information on the physiological versus toxic nature of a stimulus? Electrical stimulation will be used to assess the pattern of NFkB activation and kBdependent gene expression in response to stimuli of precisely varied intensity, duration, and frequency. Our investigations will contribute new knowledge by specifically examining the roles of NF-kB family members in the regulation of neuronal gene expression by physiological or pathophysiological stimuli. As an M.D.- Ph.D. specializing in the neurosciences, I hope to have a career as an independent investigator studying transcriptional regulation and the pathogenesis of central nervous system disease.
