UBC Theses and Dissertations
Overexpression of NF-E2 related factor 2 via viral-mediated gene transfer in vivo. Imbeault, Sophie
The transcription factor NF-E2 related factor 2 (Nrf2) is responsible for the upregulation of the cellular anti-oxidant defence system. Upon stimulation by free radicals or reactive oxygen species (ROS), the cytoplasmic-bound Nrf2 translocates to the nucleus and initiates transcription of genes containing anti-oxidant response elements (AREs) within their promoter region. Many ARE-containing genes contribute to the maintenance of redox homeostasis within the cell thus promoting cell survival. To date, limited work has been done looking at Nrf2-mediated neuroprotection in vivo. Here, we use viral-mediated gene delivery via stereotaxic injection into the adult Wistar rat brain in order to overexpress Nrf2. We exploit the capacity of 3-nitropropionic acid (3-NP) to produce ROS in order to provide an oxidative challenge to our animals. Histological analyses show reduced lesion size (lesions are ∼55 % smaller than controls, p<0.05) and increased cell number (125% and 155% for ipsi- and contralateral hemispheres, respectively, p<0.001) in Nrf2 infected animals versus green fluorescent protein infected controls. Using the same viral-gene transfer technique, we also show a significant accumulation of the Nrf2 target xCT, a cystine/glutamate antiporter, on the apical membrane of ependymal cells (200% mean pixel intensity of the basolateral membrane, p<0.001). This supports the hypothesis xCT is important in maintaining cerebrospinal fluid and extracellular fluid redox state. The inability to properly process free radicals is present in many neuropathological processes (i.e. stroke). Targeting the Nrf2 pathway or its downstream gene targets may help treat and provide prophylaxis for some of these conditions.
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